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Portfolio
Here is a list of websites that inspired me to create my own designs and portfolio.
Please take a look to see what kindo of awesome design I can make for you.
Carl Heaton
Learning Portfolio
Here is a list of websites that inspired me to create my own designs and portfolio.
Please take a look to see what kindo of awesome design I can make for you.


4
1 “Hear this word, you cows of Bashan,
who are on the mountain of Samaria,
who oppress the poor, who crush the needy,
who say to your husbands, ‘Bring, that we may drink!’
2 The Lord GOD has sworn by his holiness
that, behold, the days are coming upon you,
when they shall take you away with hooks,
even the last of you with fishhooks.
3 And you shall go out through the breaches,
each one straight ahead;
and you shall be cast out into Harmon,”
declares the LORD.
4 “Come to Bethel, and transgress;
to Gilgal, and multiply transgression;
bring your sacrifices every morning,
your tithes every three days;
5 offer a sacrifice of thanksgiving of that which is leavened,
and proclaim freewill offerings, publish them;
for so you love to do, O people of Israel!”
declares the Lord GOD.
Israel Has Not Returned to the LORD
6 “I gave you cleanness of teeth in all your cities,
and lack of bread in all your places,
yet you did not return to me,”
declares the LORD.
7 “I also withheld the rain from you
when there were yet three months to the harvest;
I would send rain on one city,
and send no rain on another city;
one field would have rain,
and the field on which it did not rain would wither;
8 so two or three cities would wander to another city
to drink water, and would not be satisfied;
yet you did not return to me,”
declares the LORD.
9 “I struck you with blight and mildew;
your many gardens and your vineyards,
your fig trees and your olive trees the locust devoured;
yet you did not return to me,”
declares the LORD.
10 “I sent among you a pestilence after the manner of Egypt;
I killed your young men with the sword,
and carried away your horses,
and I made the stench of your camp go up into your nostrils;
yet you did not return to me,”
declares the LORD.
11 “I overthrew some of you,
as when God overthrew Sodom and Gomorrah,
and you were as a brand plucked out of the burning;
yet you did not return to me,”
declares the LORD.
12 “Therefore thus I will do to you, O Israel;
because I will do this to you,
prepare to meet your God, O Israel!”
13 For behold, he who forms the mountains and creates the wind,
and declares to man what is his thought,
who makes the morning darkness,
and treads on the heights of the earth—
the LORD, the God of hosts, is his name!


#include "crc.h"
Macros | |
| #define | WIDTH (8 * sizeof(crc)) |
| #define | TOPBIT (1 << (WIDTH - 1)) |
| #define | REFLECT_DATA(X) ((unsigned char) reflect((X), 8)) |
| #define | REFLECT_REMAINDER(X) ((crc) reflect((X), WIDTH)) |
Functions | |
| static unsigned long | reflect (unsigned long data, unsigned char nBits) |
| crc | crcSlow (unsigned char const message[], int nBytes) |
| void | crcInit (void) |
| crc | crcFast (unsigned char const message[], int nBytes) |
| crc | crcFastWithPad (unsigned char const message[], int nBytes, unsigned char const pad, int nPad) |
Variables | |
| crc | crcTable [256] |
| #define REFLECT_DATA | ( | X | ) | ((unsigned char) reflect((X), 8)) |
| #define TOPBIT (1 << (WIDTH - 1)) |
| #define WIDTH (8 * sizeof(crc)) |
| crc crcFast | ( | unsigned char const | message[], |
| int | nBytes | ||
| ) |
| crc crcFastWithPad | ( | unsigned char const | message[], |
| int | nBytes, | ||
| unsigned char const | pad, | ||
| int | nPad | ||
| ) |
| void crcInit | ( | void | ) |
| crc crcSlow | ( | unsigned char const | message[], |
| int | nBytes | ||
| ) |
|
static |
| crc crcTable[256] |


Issue: DEFPACKAGE
References: CLtL section 11.7.
Issue: IN-PACKAGE-FUNCTIONALITY
Issue: MAKE-PACKAGE-USE-DEFAULT
Issue: PACKAGE-DELETION
Category: ADDITION
Edit history: Version 1, 12-Mar-88, Moon
Version 2, 23-Mar-88, Moon, changes based on discussion
Version 3, 27-Sep-88, JonL
(remove :import, :shadowing-import; allow :export to work on
imported and inherited; update references to in-package, etc.)
Version 4, 1-Oct-88, Masinter
Version 5, 6-Oct-88, Moon
Version 6, 6-Oct-88, JonL (little nits)
Version 7, 2-Nov-88, JonL
(incorporate further discussion; simplify handling of
syntactic errors; specify ordering constraints).
Problem description:
Many users incorrectly think that package operations can be performed
in any order. CLtL (p.192) contributes to this misconception.
Programmers need direction on the ordering constraint, especially for
creating packages, since doing things out of order can lead to
confusing or even intractable problems.
If the definition of a package is scattered throughout a program as a
number of individual forms, it is very easy to read a symbol before the
package setup needed to read that symbol correctly has been accomplished.
Three examples: an inherited symbol that should have been shadowed might
be accessed; a single-colon prefix might be used for a symbol that hasn't
yet been exported; an internal symbol might be created afresh where a
symbol that will later be imported or inherited was intended. These
problems can be difficult to understand or even to recognize; in some
cases it is difficult or impossible to correct the situation in the
same Lisp image.
Proposal (DEFPACKAGE:ADDITION):
Add a DEFPACKAGE macro to the language. In the description below,
'package-name' and 'symbol-name' can be a symbol or a string; if a
symbol, only its name matters, not what package it is in.
The syntax of DEFPACKAGE is
(DEFPACKAGE package-name {option}*)
where each option is a list of a keyword and arguments. Nothing in a
DEFPACKAGE form is evaluated.
Standard options for DEFPACKAGE are listed below. Except for :SIZE,
options may appear more than once (this is useful primarily for
:IMPORT-FROM and :SHADOWING-IMPORT-FROM).
(:NICKNAMES {package-name}*)
Set the package's nicknames to the specified names.
(:USE {package-name}*)
The package is to "use" the other designated packages; that is,
it will inherit from them. The default value for this option
should be the same as it is for MAKE-PACKAGE (also see the issue
(:SHADOW {symbol-name}*)
Create the specified symbols in the package being defined,
making them shadows, just as the function SHADOW would do.
(:SHADOWING-IMPORT-FROM package-name {symbol-name}*)
Find the specified symbols in the specified package, import
them into the package being defined, and place them on the
shadowing symbols list. In no case will symbols be created in
any package other than the one being defined; a continuable error
is signaled if no symbol is accessible in the package named
package-name for one of the symbol-names.
(:IMPORT-FROM package-name {symbol-name}*)
Find the specified symbols in the specified package and import
them into the package being defined. In no case will symbols be
created in a package other than the one being defined; a continuable
error is signaled if no symbol is accessible in the package named
package-name for one of the symbol-names.
(:EXPORT {symbol-name}*)
Find or create symbols with the specified names and export them.
Note an interaction with the :USE option, since inherited symbols
can be used rather than new ones created; note also an interaction
with the :IMPORT-FROM and :SHADOWING-IMPORT-FROM options, since
imported symbols can be used rather than new ones created.
(:INTERN {symbol-name}*)
Find or create symbols with the specified names. Note an
interaction with the :USE option, since inherited symbols
can be used rather than new ones created. This option is useful if
an :IMPORT-FROM or a :SHADOWING-IMPORT-FROM option in a subsequent
call to DEFPACKAGE (for some other package) expects to find these
symbols accessible but not necessarily external.
(:SIZE integer)
Declare the approximate number of symbols expected in the package.
This is an efficiency hint only, so that the package's table will
not have to be frequently re-expanded when new symbols are added
to it (e.g., by reading in a large file "in" that package).
The order in which the options occur in a DEFPACKAGE form is irrelevant;
but since the effects of the entry-making options are context-sensitive,
the order in which they will be executed is as follows:
(1) :SHADOW and :SHADOWING-IMPORT-FROM
(2) :USE
(3) :IMPORT-FROM and :INTERN
(4) :EXPORT
Shadows are established first, since they may be necessary to block
spurious name conflicts when the use link is established. Use links are
established next so that :intern and :export may refer to normally
inherited symbols. The :export is done last so that it may refer to
symbols created by any of the other options; in particular, shadows and
imported symbols can be made external. Note also the prescription on CLtL
p.178 to cover the case of calling EXPORT on an inherited symbol.
DEFPACKAGE creates the package as specified and returns it as its value.
It has no other side effects; e.g., it does not alter the value of *PACKAGE*.
The function COMPILE-FILE should treat top-level DEFPACKAGE forms the
same way it treats the other package-effecting functions (see CLtL p.182).
If the specified name already refers to an existing package, then the
name-to-package mapping for that name is not changed. At most, the
existing package will be modified to reflect the new definition; it is
undefined what happens if the new definition is at variance with the
current state of that package. If one of the specified nicknames already
refers to an existing package, then an error is signaled just the same
as MAKE-PACKAGE would. See the issue PACKAGE-DELETION for undoing the
name-to-package mapping.
Some DEFPACKAGE errors are, however, purely syntactic.
(1) An error should be signaled if :SIZE appears than once.
(2) Since extended options might be allowed by other implementations,
an error should be signaled if an option is present that is not
actually supported in this implementation.
(3) The collection of symbol-name arguments given to the options
:SHADOW, :INTERN, :IMPORT-FROM, and :SHADOWING-IMPORT-FROM must
all be disjoint; additionally, the symbol-name arguments given to
:EXPORT and :INTERN must be disjoint. If either condition is
violated, an error should be signaled.
Name conflict errors will, of course, be handled by the underlying calls to
USE-PACKAGE, IMPORT, and EXPORT.
Examples:
;;; An example that "plays it super-safe" by using only strings as names;
;;; does not even assume that the package it is read in to "uses" LISP;
;; *never* creates any symbols whatsoever in the package that it is read
;; in to.
(LISP:DEFPACKAGE "MY-PACKAGE"
(:NICKNAMES "MYPKG" "MY-PKG")
(:USE "LISP")
(:SHADOW "CAR" "CDR")
(:SHADOWING-IMPORT-FROM "VENDOR-COMMON-LISP" "CONS")
(:IMPORT-FROM "VENDOR-COMMON-LISP" "GC")
(:EXPORT "EQ" "CONS" "FROBOLA")
)
;;; A similar call, mostly using symbols rather than strings as names.
;;; Expects to be read in to a package that "uses" LISP and *may* create
;;; random internal symbols in that package (such as MY-PACKAGE etc).
(defpackage my-package
(:nicknames mypkg :MY-PKG) ;remember CL conventions for case
(:use lisp) ; conversion on symbols
(:shadow CAR :cdr #:cons)
(:export "CONS") ;yes, this is the shadowed one.
)
Rationale:
The availability of DEFPACKAGE encourages putting the entire package
definition in a single place. It also encourages putting all the package
definitions of a program in a single file, which can be loaded before
loading or compiling anything else that depends on those packages; such a
file can be read in the USER package, avoiding any initial state issues.
In addition, DEFPACKAGE allows a programming environment to process
the whole package setup as a unit, providing better error-checking and
more assistance with package problems, by dint of global knowledge of
the package setup.
Current practice:
Symbolics Common Lisp (SCL) has always had a DEFPACKAGE, and users
prefer it to individual calls to EXPORT, IMPORT, SHADOW, etc. The SCL
version of DEFPACKAGE has quite a few additional options, but none of
them appears to be necessary to propose for Common Lisp at this time.
This proposal is incompatible with Symbolics DEFPACKAGE in some ways
that will probably not cause major problems.
Cost to Implementors:
Small--DEFPACKAGE can be implemented simply as a bunch of
calls to existing functions.
Cost to Users:
Small, this is upward compatible.
Cost of non-adoption:
Packages continue to be difficult to use correctly.
Benefits:
Guide users away from using packages in ways that get them into trouble.
Esthetics:
Neutral.
Discussion:
It has been suggested that the "Put IN Seven EXtremely Random USEr
Interface COmmands" mnemonic described in CLtL p.191 could be removed;
and with possibly a few exceptions, the special handling of them by
COMPILE-FILE could be removed. As this would be an incompatible change,
it is not part of this proposal. However, a new mnemonic can be offered,
to help remember the ordering constraints mentioned above:
I REmember Six USEr Interface Expressions
Each word in the sentence corresponds to one operation listed below:
I IN-PACKAGE ;"foot" to stand on
REmember REQUIRE ;ensure pre-requisite packages
Six SHADOW ;block multiple-inheritances
USEr USE-PACKAGE ;go for it!
Interface IMPORT ;bring in "foreign" symbols
EXpressions EXPORT ;a "face" to show to others.
It is noted that DEFPACKAGE cannot be used to create two "mutually
recursive" packages, such as:
(defpackage my-package
(:use lisp your-package) ;requires 'your-package' to exist first
(:export "MY-FUN"))
(defpackage your-package
(:use lisp)
(:import-from my-package "MY-FUN") ;requires 'my-package' to exist first
(:export "MY-FUN"))
However, nothing prevents one from using the package-effecting functions
such as USE-PACKAGE, IMPORT, and EXPORT to establish such links (which
ought to be very rare) after a more standard use of DEFPACKAGE.
The macroexpansion of DEFPACKAGE could usefully canonicalize the names
into strings, so that even if a source file has random symbols in the
DEFPACKAGE form, the compiled file would only contain strings.
Frequently additional implementation-dependent options take the
form of a keyword standing by itself as an abbreviation for a list
(keyword T); this syntax should be properly reported as an unrecognized
option in implementations that do not support it.
Definition forms in Common Lisp usually just establish a name-to-object
mapping; there is little precedent for them to modify other global-context
state. For this reason, we didn't want DEFPACKAGE also to "go" into the
new package. If it did so, like IN-PACKAGE, then the following reasonable
file would become confused, because it wouldn't all be in one package:
(in-package "USER")
(defpackage "WATER" (:use "LISP") (:export "FISH"))
(defpackage "ALCHEMY" (:use "LISP" "PHLOGISTON) (:export gold))
Should the token 'gold' be read while in the USER package, or in the
the WATER package?
The issue IN-PACKAGE-FUNCTIONALITY recommends that IN-PACKAGE be
incompatibly changed to recognize only existing packages, not to create
them. IN-PACKAGE would then not accept any keyword arguments.
The function MAKE-PACKAGE might also be extended to take all the keywords
that DEFPACKAGE does. This could be the subject of a separate cleanup.


These are collections of tasks that are imported together.
To import them into gulp:
var
gulp = require('gulp'),
// modified to point to semantic folder
install = require('tasks/collections/install')
;
gulp = install(gulp);
// tasks are now injected and ready to be used
gulp.start('install');


Nick Hirakawa
Programmer / Web Developer / Software Engineer
I currently work at HubSpot in Cambridge, MA
My interests lie in distributed systems, web development, networking, databases, and information retrieval.
I currently work at HubSpot in Cambridge, MA
My interests lie in distributed systems, web development, networking, databases, and information retrieval.


MY~PROGRAM--One line description here
MY~PROGRAM [OPTIONS] <file>
A full description of the application and its features.
May include numerous subsections (i.e. =head2, =head3, etc.)
[...]
-h = This usage.
-v = Be verbose.
-V = Show version, copyright and license information.
Written by Miroslav Vidovic.
MIT LICENSE ...
command1, command2, link url...


We make every effort to comply to ADA standards, and Section 508 of the Rehabilitation Act. Visit our ADA page here. If you have any problems with any of these pages, please contact the webmaster with the page address and problems encountered.
You may view our Privacy Policy here.


{% extends "base.html" %} {% block tag_additional_stylesheets %} {% endblock %} {% block tag_header_additional_content %}
Here's what we think you should be reading.
More Details


Reports¶
The report consists of five parts.
Tail Detection
Goodness-of-Fit Tests
Fit Values
Risk assessment
Plots
Tail Detection¶
In this part contains the size of the data set that was analyzed, the minimal value for the \(AU^2\) as well as information on the estimated tail.
Goodness-of-Fit Tests¶
Goodness-of-Fit values for the Cramér-von Mises and Anderson-Darling teststatistics.
Fit Values¶
Fitted values of the generalized Pareto distribution (GPD).
Risk assessment¶
This part contains the Value-at-Risk and the Conditional-Value-at-Risk for the 0.95, 0.97, 0.99 and 0.999 quantiles.
Plots¶
A plot of the input data, a plot of the three teststatistics (\(AU^2\), Cramér-von Mises and Anderson-Darling) for the different tails and a plot of the fitted tail.


{% include head.html %}
{% include header.html %}
{{ content }}
{% assign featured = strapi.collections.servers | sample:2 %} {%- for feature in featured -%}
Servers of the day
{{ feature.name }}
{{ feature.description | truncate: 125 }}
Visit Website
{%- endfor -%}
Server
Uptime
Maintainer
Support
Description
{% assign servers = strapi.collections.servers | sample:100 %} {%- for server in servers -%}
{{ server.domain }}
Stats
Contact
Support
{{ server.description }}
{%- endfor -%}
{% include footer.html %} {% include javascript.html %}


This is the testLambda Controller route:
{{testLambda.response}}
Elapsed Time: {{testLambda.elapsedTime}}ms


Set how many columns you wish to have in your group. This group currently has {{ model.fieldset.containers.length }}


1-55. Glass optical fibers have low loss between the infrared and ultra- violet absorptive regions. The approximate wavelength of operation for glass optical fibers is in which of the following ranges?
1. 1 nm to 700 nm 2. 700 nm to 1600 nm 3. 1600 nm to 9000 nm 4. 9 µm to 20 µm
1-56. Increased extrinsic absorption at 950 nm, 1,250 nm, and 1,383 nm is caused by what impurity in glass optical fibers?
1. Phosphorus 2. Germanium 3. Titanium 4. Water
1-57. Which type of scattering loss is proportional to the reciprocal of the fourth power of the wavelength of the light?
1. Mie 2. Raman 3. Rayleigh 4. Brillouin
1-58. A radius of curvature is larger than the fiber diameter in which of the following types of fiber bends?
1. Macrobends 2. Microbends 3. Gentle bends 4. Serpentine bends
1-59. Only in multimode fibers does which of the following types of dispersion occur?
1. Modal 2. Material 3. Waveguide 4. Chromatic
1-60. When different colors of light travel through the fiber at different speeds, which of the following types of dispersion occurs?
1. Modal 2. Intramodal (chromatic) 3. Intermodal 4. Atmospheric
7
ASSIGNMENT 2 Textbook assignment: Chapter 3, “Optical Fibers and Cables,” pages 3-1 through 3-26. Chapter 4,
“Optical Splices, Connectors, and Couplers,” pages 4-1 through 4-34. ___________________________________________________________________________________
2-1. In a step-index fiber, the refractive index profile of the fiber core has which of the following characteristics?
1. It is uniform over the fiber core 2. It linearly decreases from a
3. It is parabolic with a maximum index of refraction at the center and a minimum index of refraction at the core-cladding boundary
4. It linearly increases from a minimum at the fiber center to a maximum at the core cladding boundary
2-2. In a graded-index fiber, the refractive index profile of the fiber core is best described by which of the following statements?
1. It is uniform over the fiber core 2. It linearly decreases from a
3. It is parabolic with a maximum index of refraction at the center and a minimum index of refraction at the core-cladding boundary
4. It linearly increases from a minimum at the fiber center to a maximum at the core cladding boundary
2-3. Which of the following multimode fiber core sizes is NOT a standard commercial fiber size?
1.  Elements other than silicon and oxygen are added to glass material by the fiber manufacturer to change its index of refraction. What are these elements called?
1. Spices 2. Dopants 3. Additives 4. Impurities
2-5. Compared to multimode step-index fibers, do multimode graded-index fibers have lower, higher, or approximately equal bandwidths?
1. Lower 2. Higher 3. Approximately equal
2-6. In multimode graded-index fibers, is the index of refraction of the glass at the center of the fiber core lower, higher, or approximately equal to the index of re- fraction of the cladding glass?
1. Lower 2. Higher 3. Approximately equal
2-7. For a multimode graded-index fiber, the numerical aperture is at its maximum value at which of the following locations?
1. At the fiber axis 2. At the core-cladding interface 3. Half way between the fiber center
and the core-cladding interface 4. One-fourth of the way between the
8
2-8. In multimode fiber, all light rays have to propagate all of the way to the core- cladding interface before they are reflected back toward the fiber axis.
1. True 2. False
2-9. A step-index multimode fiber and a graded-index multimode fiber have the same core and cladding sizes and the same refractive index difference. Which fiber type, if either, will accept light more easily and have more propagating modes?
1. Step-index fiber 2. Graded-index fiber 3. Neither; they will behave
2-10. The multimode graded-index fiber that has the best bend performance and will show the least amount of optical degradation if mishandled is what size?
1.  The attributes of the 62.5/125- m m fiber do NOT include which of the following factors?
1. Low loss 2. High bandwidth 3. Low bending sensitivity 4. Low source to fiber coupling
2-12. What are the two basic types of single mode step-index fibers?
1. Low NA and high NA 2. Solid core and air core 3. Enriched clad and depressed 4. Matched clad and depressed clad
2-13. For wavelengths greater than its cutoff wavelength, a typical single mode fiber is allowed to propagate a total of how many modes, if any?
1. 1 only 2. 10 only 3. 100 4. None
2-14. Fibers are single mode at a particular wavelength only when V < 2.405. Under what condition, if any, will the fiber cease to be single mode?
1. When the wavelength of the light is greater than the cutoff wavelength
2. When the wavelength of the light is less than the cutoff wavelength
3. None
2-15. The use of plastic-clad silica and all plastic fibers has what primary drawback?
1. Higher NA 2. Higher cost 3. Higher bandwidth 4. Limited optical performance
2-16. In the fabrication of silica optical fibers, which of the following processes may be used?
1. Outside vapor phase oxidation (OVPO)
2. Inside vapor phase oxidation (IVPO) 3. Vapor phase axial deposition (VAD) 4. All of the above
2-17. In making a preform, layers of glass powder are deposited on the inside or outside of a glass rod or tube. What is this glass powder called?
1. Soot 2. Smoke 3. Preform 4. Afterburn
9
2-18. The process used in drawing the fiber is best described by which of the following statements?
1. The preform is melted and the molten glass is molded, using special fiber molds
2. The preform is softened and the glass is pulled into a thin glass filament
3. The preform is softened and the glass is rolled into a thin glass filament
4.  To protect the fiber from contaminants in the drawing process, what substance is added over the fiber?
1. Water 2. Coating 3. Preform 4. Cladding
2-20. Most fiber optic cable structures contain which of the following items?
1. Buffers only 2. Jackets only 3. Buffers and jackets only 4. Buffers, jackets, and strength
2-21. Properly designed optical cable structures perform which of the following functions?
1. Protect the optical fibers from mechanical stresses, damage, and breakage
2. Increase the tensile stress on the fiber 3. Decrease the attenuation of the fiber 4. All of the above
2-22. The fiber buffer performs which of the following functions?
1. Protects the fiber from micro-bends 2. Provides additional mechanical
protection 3. Helps preserve the fiber's inherent
strength 4. All of the above
2-23. Navy shipboard fiber optic cables should NOT contain which of the following materials as a strength member?
1. Steel wire 2. Arimid yarns 3. Carbon fibers 4. Glass-reinforced plastics
2-24. In the materials of a Navy shipboard fiber optic cable jacket, which of the following properties is NOT desirable?
1. High abrasion resistance 2. High flame retardance 3. High halogen content 4. Low toxicity
2-25. Most commercial fiber optic cable jacket materials are suitable for use in Navy shipboard applications.
1. True 2. False
2-26. For low-density fiber Navy ship- board applications, which cable designs, if any, are preferred?
1. Stranded cable 2. Ribbon cable 3. OFCC cable 4. None; they are all equally effective
10
2-27. When compared with other cable designs, the OFCC fiber optic cable has which of the following advantages?
1. Ruggedness only 2. Ease of handling only 3. Ruggedness and ease of handling 4. Relative small size
2-28. The only advantage of the stranded cable design over the OFCC cable design is
1. greater ruggedness 2. better fiber protection 3. smaller size for the same fiber count 4. better water-blocking performance
2-29. A particular fiber optic cable design has the highest fiber count possible in the smallest size. But it is difficult to use, shows susceptibility to fiber damage during fiber breakout, and has poor bending and water-blocking performance. Which of the following designs fits this description?
1. OFCC cable 2. Stranded cable 3. Ribbon cable
2-30. A fiber optic connection that is typically intended to be permanent is what type, if any?
1. Mechanical splice 2. Connector 3. Coupler 4. None; they are all intended to be
2-31. Easy coupling and uncoupling of optical fibers are allowed by what type of fiber optic connection, if any?
1. Splice 2. Coupler 3. Connector 4. None; all are equally difficult
2-32. The distribution or combination of optical signals among fibers uses which type of fiber optic connection, if any?
1. Splice 2. Coupler 3. Connector 4. None; it is not possible to distribute
2-33. Coupling loss in a fiber optic connection may be caused by which of the following conditions?
1. Poor fiber alignment 2. Poor fiber end preparation 3. Differences in optical properties
between connected fibers 4. All of the above
2-34. The loss in optical power through a connection is described by what relationship, if any?
1. Log relationship 2. Linear relationship 3. Exponential relationship 4. None; there is no way to describe the
2-35. An intrinsic coupling loss may be caused by which of the following conditions?
1. Fiber separation 2. Angular misalignment 3. Fiber geometry mismatches 4. Poor fiber end preparation
2-36. In connections that have an air gap, the reflective losses can be minimized by taking which of the following actions?
1. Polishing the fiber ends more finely 2. Cleaning the fiber ends carefully with
alcohol 3. Filling the air gap with an index
matching gel 4. Heating the connection to an elevated
11
2-37. A main source of extrinsic coupling loss in fiber to fiber connections is caused by which of the following conditions?
1. Fiber mismatches 2. Poor fiber alignment 3. Poor fiber end preparation
2-38. Which of the following conditions is NOT a form of poor fiber alignment?
1. NA mismatch 2. Fiber separation 3. Lateral misalignment 4. Angular misalignment
2-39. For mating fibers to touch when a connector is assembled, which of the following polishing techniques was developed?
1. Fresnel polish 2. Rayleigh polish 3. Circular polish 4. Physical contact polish
2-40. Single mode fibers are less sensitive to alignment errors than multimode fibers because of their small core size.
1. True 2. False
2-41. The fiber cleaving process includes which of the following actions?
1. Cutting the fiber with a cleaver 2. Bending the fiber until it breaks 3. Lightly nicking the fiber and
applying tension until it breaks 4. Sawing the fiber with a special fiber
2-42. To remove most of the surface imperfections introduced in the fiber cleaving process in most fiber optic connections, what action should be taken?
1. Polish the fiber end 2. Cover the fiber end face with epoxy 3. Clean the fiber end face with alcohol 4. Cover the fiber end face with index
2-43. The connector end face should be inspected for scratches and shattered fiber ends by which of the following methods?
1. The naked eye 2. A 10x eye loupe 3. An electron microscope 4. A 200x-400x microscope
2-44. In Navy fiber optic applications, losses from fiber mismatches are minimized by which of the following actions?
1. Polishing the fiber ends 2. Using index matching gels 3. Using index matching epoxies 4. Using Navy specification fibers with
2-45. Fiber optic splices are typically used in which of the following conditions?
1. When repeated connections or disconnections are desired only
2. When repeated connections or disconnections are unnecessary only
3. When low loss connections are required only
4. When repeated connections or disconnections are unnecessary and when low loss connections are required
12
2-46. What are the two basic categories of fiber splices?
1. Glass and plastic 2. Metal and ceramic 3. V-groove and rotary 4. Mechanical and fusion
2-47. For shipboard applications, which of the following types of splices is recommended?
1. Fusion 2. Rotary 3. V-groove 4. Ceramic alignment tube
2-48. The assembly of a rotary splice is which of the following actions?
1.  Cleave fiber ends, insert into each end of a glass tube filled with index matching gel, and twist on splice end caps
3. Break glass tube at center, fill each half with epoxy, insert fibers into each half, cure adhesive with ultraviolet light, and polish and place polished ends together with alignment sleeve
4. Cleave fiber ends, insert fibers into splice, and crimp in place
2-49. The basic process used in making fusion splices is which of the following methods?
1. Gluing the fiber ends together 2. Melting the fiber ends together 3. Polishing the fiber ends and placing
them together 4. Cleaving the fiber ends and placing
2-50. Fusion splicing is not recommended for Navy use for all of the following reasons except which one?
1. Low splice yields 2. Low splice losses 3. Long splicing times 4. High level of expertise required for
2-51. The total loss of a fiber optic connector should always remain below which of the following values?
1. 1 dB 2. 2 dB 3. 5 dB 4. 10 dB
2-52. What are the two basic types of fiber optic connectors?
1. V-groove and ribbon 2. Three rod and biconical 3. Ceramic and stainless steel 4. Butt-jointed and expanded-beam
2-53. Single fiber butt-jointed connections generally consist of which of the following parts?
1. Plug and receptacle 2. Ferrule and alignment clip 3. Two plugs and an adapter 4. One plug and two adapters
2-54. In ceramic ferrules, the center hole is created by which of the following processes?
1. With a microdrill 2. With a laser drill 3. By forming the ferrule around a
precision wire 4. With a small water jet
13
2-55. The standard connector for Navy light- duty applications is of which of the following styles?
1. ST� 2. SMA 3. Array 4. Biconical
2-56. Light-duty connectors are intended for use in all but which of the following locations?
1. Junction boxes 2. Equipment enclosures 3. Environmentally protected locations 4. Exposed equipment interface
2-57. A standard connector for Navy heavy- duty applications is of which of the following styles?
1. MIL-C-83526 connector 2. MIL-C-28876 connector 3. Biconical connector 4. Array connector
2-58. In a heavy-duty connector, what are the two types of terminals called?
1. Plugs and adapters 2. Type A and type B 3. Pins and sockets 4. Nuts and bolts
2-59. Fiber optic couplers attenuate the optical signal much more than a connector or a splice.
1. True 2. False
2-60. Active fiber optic couplers are called active fiber optic couplers for which of the following reasons?
1. Because they contain moving parts 2. Because they switch the optical
signal between different parts 3. Because they contain active devices,
including sources and detectors 4. Because they move through the
2-61. An optical coupler has one input port and two output ports. Which of the following types of couplers is it?
1. Optical splitter 2. Optical combiner 3. Star coupler 4. Tree coupler
2-62. An optical coupler has two input ports and one output port. Which of the following types of couplers is it?
1. Optical splitter 2. Optical combiner 3. Star coupler 4. Tree coupler
2-63. An optical coupler has one input port and several output ports. Which of the following types of couplers is it?
1. T-coupler 2. Star coupler 3. Tree coupler 4. Optical splitter
2-64. An optical coupler has several input ports and several output ports. Which of the following types of couplers is it?
1. X-coupler 2. T-coupler 3. Star coupler 4. Tree coupler
14
ASSIGNMENT 3 Textbook assignment: Chapter 5, “Fiber Optic Measurement Techniques,” pages 5-1 through 5-32.
Chapter 6, “Optical Sources and Fiber Optic Transmitters,” pages 6-1 through 6-16. ___________________________________________________________________________________
3-1. Manufacturers should measure some component parameters during and after component manufacture for which of the following reasons?
1. To characterize the component design
2. To verify the quality of the manufactured parts
3. To determine if the component has been damaged in the shipping process
4. To determine if the installation process has degraded the component performance beyond allowable limits
3-2. End users should measure some component parameters upon receipt before installing a component into a fiber optic system for which of the following reasons?
1. To characterize the component design
2. To verify the quality of the manufactured parts
3. To determine if the component has been damaged in the shipping process
3-3. End users should measure some component parameters after installation of the component in the fiber optic system for which of the following reasons?
1. To characterize the component design
2. To verify the quality of the manufactured parts
3. To determine if the component has been damaged in the shipping process
4. To determine if the installation process has degraded the component performance beyond allowable limits
3-4. Standard test methods used for testing fiber optic components or systems can be found in which of the following test documents?
1. EIA/TIA-455 only 2. EIA/TIA-526 only 3. EIA/TIA-455 and EIA/TIA 526 4. MIL-STD 2196
3-5. In laboratory fiber attenuation measurements, the output optical power of a long fiber is compared with the optical power launched into that same fiber two meters from the optical source. This method of measuring the optical attenuation is called the
1. OTDR method 2. fiber method 3. cutback method 4. two-point method
15
3-6. Which of the following are considered launch conditions?
1. The temperature at the time of measurement
2. The humidity at the time of measurement
3. The way power is launched into the optical fiber
4. The type of connector or splice used on the fiber
3-7. Launch conditions in an attenuation measurement are important to measurement personnel for which of the following reasons?
1. The attenuation measured for each different launch condition will be different
2. The use of the wrong launch condition will damage the optical power meter
3. The fibers will only transmit light launched in one particular manner
4. The use of the wrong launch condition will damage the fiber
3-8. For single mode fiber, what method is typically used to assure that power is launched into only the fundamental mode?
1. Only LEDs are used as test optical sources
2. Only lasers are used as test optical sources
3. The fiber is always placed at a 45º angle with respect to the plane of the source
4. A 30-mm diameter mandrel or free- form loop is applied at the launch end of the fiber
3-9. What does the term overfilled launch mean?
1. When too much power is launched into the fiber
2. When not enough power is launched into the fiber
3. When light is launched only into the low order mode
4. When the launch spot size and the angular distribution are larger than that of fiber core
3-10. In what part of the fiber does an underfilled launch concentrate most of the optical power?
1. In the center of the fiber 2. At the edge of the fiber 3. Over all of the fiber 4. In the cladding
3-11. What is a mode filter?
1. A device that converts cladding power to core power
2. A device that removes any cladding power from the fiber
3. A device that attenuates specific modes propagating in the core of the fiber
4. A device that attenuates specific wavelengths of light in the core of the fiber
3-12. To remove high-order modes in multimode fibers, which of the following mode filters is normally used?
1. Bessel filter 2. Bandpass filter 3. Mandrel wrap filter 4. Neutral density filter
16
3-13. What is the wavelength called over which the fiber will propagate only one mode?
1. Cutoff wavelength 2. Fresnel wavelength 3. Cutback wavelength 4. Rayleigh wavelength
3-14. Determining the cutoff wavelength of a single mode fiber involves finding the wavelength above which the power transmitted through the fiber decreases abruptly.
1. True 2. False
3-15. When the cutoff wavelength is reached, why does the transmitted power in a single mode fiber abruptly decrease?
1. The fiber absorption increases at the cutoff wavelength
2. The fiber scattering increases at the cutoff wavelength
3. The fiber diffusion increases at the cutoff wavelength
4. The second-order mode ceases to propagate at the cutoff wave- length
3-16. The spreading of a light pulse as it travels along the fiber is caused by what mechanism?
1. Diffraction 2. Attenuation 3. Absorption 4. Dispersion
3-17. In a fiber, the intermodal (modal) dispersion is greatest under what condition?
1. When the input pulse has a long rise time
2. When all fiber modes are excited 3. When the input pulse has an
extremely high amount of power 4. When the source spectrum contains
3-18. The fiber bandwidth (- 3 dB) is defined as the lowest frequency at which the magnitude of the fiber frequency response has decreased to what portion of its zero-frequency value?
1. One-tenth 2. One-fifth 3. One-half 4. Three-fourths
3-19. Modal bandwidth is normally given in what units?
1. GHz 2. MHz 3. MHz/km 4. MHz-km
3-20. Why does chromatic dispersion occur?
1. Because different fiber modes have different propagation speeds
2. Because different colors of light travel through the fiber at different speeds
3. Because different colors of light are attenuated differently in the fiber
4. Because different fiber modes are attenuated differently in the fiber
3-21. End users perform fiber geometry measurements for which of the following reasons?
1. To reduce system bandwidth limitations
2. To separate bigger fibers from smaller fibers
3. To reduce system attenuation and coupling losses from fiber mismatches
4. To determine which connector to use
17
3-22. Cladding diameter, cladding noncircularity, core-cladding concentricity error, and core noncircularity are measured by which of the following techniques?
1. Micrometer calipers 2. Electron microscopes 3. Video cameras attached to a
computer for digital analysis 4. Ruler
3-23. The core diameter of a multimode fiber is defined by which of the following measurements?
1. The distance between the 50% points of the measured near-field distribution
2. The distance between the 50% points of the measured far-field distribution
3. The distance between the 2.5% points of the measured near-field distribution
4. The distance between the 2.5% points of the measured far-field distribution
3-24. The fiber near-field is which of the following regions?
1. The region close to the fiber-end face, within a few cm of the end face
2. The region within 3 to 5 cm of the fiber-end face
3. The region about one foot of the fiber-end face
4. The region far from the fiber- end face
3-25. The fiber far-field is which of the following regions?
1. The region close to the fiber-end face, within a few cm of the end face
2. The region far from the fiber-end face, greater than a few cm for multimode and mm for single mode
3. The region exactly next to the fiber- end face
4. Anywhere inside the acceptance cone of the fiber
3-26. The far-field power distribution describes the emitted power per unit as a function of the angle ÿ from the fiber axis some distance from the fiber-end face.
1. True 2. False
3-27. The numerical aperture of a multi- mode fiber is best described by which of the following definitions?
1. Half the difference between the 50% angles of the far-field distribution
2. Half the difference between the 50% angles of the near-field distribution
3. Half the difference between the 5% angles of the near-field distribution
4. Half the difference between the 5% angles of the far-field distribution
3-28. The mode field diameter of a single mode fiber relates to which of the following factors?
1. The cladding diameter of a multimode fiber
2. The cladding diameter of a single mode fiber
3. The spot size of the fundamental mode of a single mode fiber
4. The coating diameter of the single mode fiber
18
3-29. Insertion loss is determined by which of the following techniques?
1. The power transmitted through a component is compared to the power transmitted through the fiber or the cable before the component was inserted
2. The power transmitted through a component with a mandrel wrap on the fiber is compared to the power transmitted through the component without a mandrel wrap inserted
3. The power transmitted through a cable is compared to the power transmitted through a similar piece of cable
4. The power transmitted through a connector is compared to the power transmitted through a similar connector
3-30. The return loss of a fiber optic component is which of the following measurements?
1. The difference in the power loss when a component is measured in reverse directions
2. The amount of loss of the reflected light compared with the power of the incident beam at the interface
3. The amount of loss of the reflected light compared with the transmitted light at a component
3-31. Some properties may change during installation; therefore, they are typically measured in the field. All of the following measurements should be made in the field except which one?
1. Fiber loss 2. Connector/splice return loss 3. Connector/splice insertion loss 4. NA
3-32. Field loss measurements are made by using which of the following test equipments?
1. Low power calorimeters 2. Optical sources and power meters
only 3. Optical time domain reflectometers
only 4. Optical sources and power meters;
3-33. Measurements made with an optical time domain reflectometer are more accurate than those made with an optical source and an optical power meter.
1. True 2. False
3-34. An OTDR should not be used to measure optical fibers or links that are less than a specific minimum length. What is that length?
1.  The initial pulse (or spike) at the beginning and at most connections in a link on the OTDR trace is caused by which of the following processes?
1. Reflected power at each air gap in the link
2. Extremely high losses at the beginning of each piece of fiber
3. Amplification of the OTDR pulse at the beginning of each piece of fiber
4. Second harmonic generation at the beginning of each piece of fiber
19
3-36. When OTDR measurements are made, a dead zone fiber is used for what reason?
1. To compensate for the inaccuracy of the OTDR
2. To match the fiber types at the first connection
3. To maximize the reflectance at the first connection
4. To reduce the effect of the initial reflection at the OTDR on the measurement
3-37. When fiber attenuation is measured with an OTDR, the initial cursor, Z1, should be placed at what point along the OTDR trace?
1. Just before the connector or the splice at the beginning of the fiber
2. On the gradual downward part of the trace just before the ending connector or splice
3. On the steep downward part of the trace just after the beginning connector or the splice
4. On the gradual downward part of the trace just after the reflective spike from the beginning connector or splice
3-38. When fiber attenuation is measured with an OTDR, the end cursor, Z 2, should be placed at what point along the OTDR trace?
1. Just before the connector or the splice at the beginning of the fiber
2. On the gradual downward part of the trace just before the ending connector or splice
3. On the steep downward part of the trace just after the beginning connector or splice
4. On the gradual downward part of the trace just after the reflective spike from the beginning connector or splice
3-39. When the distance between the ends of a fiber is measured with an OTDR, the initial cursor should be placed at what point along the OTDR trace?
1. Just before the connector or the splice at the beginning of the fiber
2. On the steep downward part of the trace just after the beginning connector or splice
3. On the gradual downward part of the trace just after the reflective spike from the beginning connector or splice
4. On the gradual downward part of the trace just before the ending connector or splice
3-40. OTDR measurements should be performed in each direction and averaged for which of the following reasons?
1. OTDRs are not consistent measurement tools; therefore, multiple measurements must be made
2. Variations in fiber properties (backscattering) change the OTDR measurement, depending on the direction of the measurement; bidirectional averaging eliminates these effects
3. Fibers transmit preferentially in one direction; therefore, measurements must be made to determine the preferential direction
3-41. When a point defect (a connector or a splice) exhibits an apparent gain in power in one direction, it exhibits which of the following properties in the other direction?
1. The same apparent gain in power 2. An exaggerated loss in power 3. A slight loss in power 4. No gain or loss in power
20
3-42. When using a light source and a power meter to make link loss measurements, which of the following steps should you perform first?
1. Connect the reference jumper between the source and the power meter
2. Connect the reference jumper and one test jumper between the source and the power meter
3. Connect the link directly between the source and the power meter
4. Connect the link directly between two power meters
3-43. During the measurement of the link's output optical power, the test setup is described by which of the following orders?
1. Source, test jumper, link, test jumper, power meter
2. Source, test jumper, link, power meter
3. Source, link, test jumper, power meter
4. Source, link, power meter
3-44. What is the function of a fiber optic transmitter?
1. To amplify optical signals and launch the amplified optical signals into an optical fiber
2. To convert electrical signals into optical signals and launch the optical signals into an optical fiber
3. To convert optical signals into electrical signals only
4. To convert electrical signals into optical signals and transmit the optical signals through the air
3-45. Which of the following items is/are part of a fiber optic transmitter?
1. An optical source only 2. A source drive circuit only 3. An optical source and a source drive
circuit only 4. An optical source, a source drive
3-46. An optical source has which of the following functions?
1. To convert light to electrical energy (current)
2. To amplify the electrical signal 3. To convert electrical energy into
light 4. To convert light into sound
3-47. Which of the following properties are NOT desired properties of an optical source?
1. Be compatible in size to low-loss optical fibers
2. Emit light at wavelengths that maximize fiber loss and dispersion
3. Maintain stable operation in changing environmental conditions
4. Cost less and be more reliable than electrical devices
3-48. Fiber optic communication systems typically operate in what three wavelength windows?
1. 400 nm, 850 nm, and 1550 nm 2. 400 nm, 900 nm, and 1400 nm 3. 850 nm, 1300 nm, and 1550 nm 4. 1300 nm, 2000 nm, and 4000 nm
21
3-49. Incoherent light has what type of lightwaves?
1. Lightwaves that are produced by lasers
2. Lightwaves that lack a fixed-phase relationship
3. Lightwaves that have a fixed-phase relationship
4. Lightwaves that contain only one wavelength of light
3-50. Semiconductor LEDs emit which of the following kinds of light?
1. Incoherent 2. Coherent only 3. Monochromatic only 4. Coherent and monochromatic
3-51. Semiconductor lasers emit which of the following kinds of light?
1. Spontaneous 2. Incoherent 3. Coherent 4. All of the above
3-52. All of the light emitted by a semiconductor laser or LED is coupled into an optical fiber.
1. True 2. False
3-53. Relevant optical power does NOT depend on which of the following factors?
1. The angles over which the source emits light
2. The size of the source's light- emitting area relative to the fiber core size
3. The alignment of the source and the fiber
4. The dopants in the semiconductor material
3-54. What is it called when the fiber end face is directly placed over the source emitting region?
1. Butt coupling 2. Lensed coupling 3. Evanescent coupling 4. Fresnel coupling
3-55. What are the two most common semiconductor materials used in electronic and electro-optic devices?
1. Germanium and aluminum 2. Silicon and gallium arsenide 3. Indium and zirconium 4. Zinc and platinum
3-56. LEDs produce light by what process?
1. Combustion 2. Stimulated emission 3. Spontaneous emission 4. Photosynthesis
3-57. Lasers produce light by what process?
1. Combustion 2. Stimulated emission 3. Spontaneous emission 4. Photosynthesis
3-58. Stimulated emission is the random generation of photons within the active area of an LED.
1. True 2. False
3-59. In an optical source, the input electrical energy is converted to light and which of the following other forms of energy?
1. Gravitational 2. Sound 3. Heat 4. All of the above
22
6-16. Chapter 7, “Optical Detectors and Fiber Optic Receivers,” pages 7-1 through 7-14. Chapter 8, “Fiber Optic Links,” pages 8-1 through 8-11.
4-1. Which of the following components is NOT one of the basic types of LEDs used for fiber optic communication systems?
1. Surface-emitting LED 2. Edge-emitting LED 3. Superluminescent diode 4. Avalanche photodiode
4-2. In low and moderate data rate applications, which of the following source types are typically used?
1. SLEDs only 2. ELEDs only 3. SLEDs and ELEDs 4. Lasers
4-3. Compared to SLEDs, ELEDs have all except which of the following properties?
1. Emit light in a narrower emission angle than SLEDs
2. Couple more power into small NA fibers than SLEDs
3. Emit power over a wider spectral range than SLEDs
4. Are more temperature sensitive than SLED
4-4. Which of the following definitions best describes the term laser mode?
1. The condition of the laser, either lasing or not lasing
2. The selected wavelengths that the laser emits
3. The maximum modulation frequency possible for the laser
4. The maximum angle of the emitted beam from the laser
4-5. What does the term lasing threshold mean?
1. The lowest drive current level at which the output of the laser results primarily from stimulated emission
2. The polished or cut surfaces at each end of the active stripe in the laser
3. The shortest wavelength that the laser emits
4. The front step of the laser chip
4-6. Transmitters containing what source type, if any, will typically require the most complex circuitry?
1. SLED 2. ELED 3. LD 4. None; all are roughly the same
4-7. Which of the following types of sources is typically the most temperature sensitive?
1. SLEDs 2. ELEDs 3. SLDs 4. LDs
4-8. Which of the following types of sources have very similar semi-conductor designs?
1. SLEDs, ELEDs, SLDs 2. SLEDs, ELEDs, lasers 3. SLEDs, SLDs, lasers 4. ELEDs, SLDs, lasers
23
4-9. What kind of circuitry do most lasers have that compensates for the sensitivity of the laser to its environment?
1. Linearization circuitry 2. Automatic overload protection
circuitry 3. Power control circuitry 4. Low-pass filter circuitry
4-10. For lasers that are to be operated under widely changing thermal conditions, what device is normally included in the laser package?
1. Automatic overload protection circuitry
2. Thermo electric cooler 3. Variable attenuator 4. Low-pass filter
4-11. For fiber optic transmitters, which of the following are typical output interfaces?
1. Optical fiber pigtails 2. Single fiber cable pigtails 3. Optical connectors 4. All of the above
4-12. Which of the following types of transmitters are typically the most expensive?
1. SLEDs 2. ELEDs 3. SLDs 4. LDs
4-13. Which of the following are possible transmitter package types used in Navy shipboard applications?
1. Hybrid microcircuit dual inline packages (DIPs) only
2. Circuit cards only 3. Stand-alone fiber optic converters
only 4. Hybrid microcircuit dual inline
4-14. In shipboard applications with moderate data rates (50 to 200 Mbps), which of the following source types will typically be used?
1. 850-nm LEDs only 2. 1300-nm LEDs only 3. 850-nm and 1300-nm LEDs 4. Lasers
4-15. In shipboard applications with low data rates (0 to 50 Mbps), which of the following source types will typically be used?
1. 850-nm LEDs only 2. 1300-nm LEDs only 3. Either 850-nm LEDs or 1300 nm
LEDs depending on design 4. Lasers
4-16. Which of the following fiber optic components is responsible for converting the weakened and distorted optical signal back to an electrical signal?
1. Fiber optic transmitter 2. Fiber optic amplifier 3. Fiber optic receiver 4. Fiber optic coupler
4-17. Which of the following is NOT a typical part of a fiber optic receiver?
1. Optical detector 2. Thermo electric cooler 3. Low-noise amplifier 4. Output signal conditioning circuity
24
4-18. The term receiver sensitivity has which of the following meanings?
1. The minimum amount of optical power required to achieve a specific receiver performance
2. The range of optical power levels over which the receiver operates within specified values
3. The ratio of the output photocurrent to the incident optical power
4. The wavelengths over which the receiver will properly operate
4-19. The term dynamic range has which of the following meanings?
1. The minimum amount of optical power required to achieve a specific receiver performance
2. The range of optical power levels over which the receiver operates within specified values
3. The ratio of the output photocurrent to the incident optical power
4. The wavelengths over which the receiver will properly operate
4-20. An optical detector has which of the following purposes?
1. To convert an optical signal into an electrical signal
2. To convert an electrical signal to an optical signal
3. To amplify the optical output signal 4. To generate an optical pulse
4-21. Which of the following attributes is NOT a desirable attribute of an optical detector?
1. Be compatible in size to low-loss optical fibers
2. Contribute high amounts of noise to the system
3. Have a high sensitivity at the operating wavelength of the optical source
4. Maintain stable operation in changing environmental conditions
4-22. In fiber optic systems, what are the principal types of detectors used?
1. Integrating spheres 2. Photon counters 3. Photomultiplier tubes 4. PIN photodiodes and APDs
4-23. Which of the following factors does NOT affect the amount of current generated by a photodiode?
1. The responsivity of the photodiode at the wavelength of the incident light
2. The data rate of the incoming optical signal
3. The size of the photodiode active area relative to the fiber core size
4. The alignment of the fiber and the photodiode
4-24. Which of the following terms is defined as the current produced by an optical detector because of the optical energy incident on its active area?
1. Photocurrent 2. Active current 3. Incident current 4. Threshold current
25
4-25. The term detector responsivity has which of the following meanings?
1. The minimum amount of optical power required to achieve a specific receiver performance
2. The range of optical power levels over which the receiver operates within specified values
3. The ratio of the output photocurrent to the incident optical power
4. The wavelengths over which the detector will convert light to electric current
4-26. The responsivity of an optical detector is constant over wavelength; that is, an optical detector does not absorb some wavelengths better than others.
1. True 2. False
4-27. A PIN photodiode usually operates in what way?
1. Reverse-bias voltage applied 2. Forward-bias voltage applied 3. No bias voltage applied
4-28. What is the name of the current produced by a photodiode when no light is incident on the device?
1. Threshold current 2. Spill current 3. Photocurrent 4. Dark current
4-29. Reverse-biased photodetectors are highly linear devices with respect to output photocurrent and input optical power.
1. True 2. False
4-30. When compared to the reverse-bias voltage of a PIN photodiode, the reverse- bias of an APD is which of the following sizes?
1. Much less than the PIN's 2. About the same as the PIN's 3. A little greater than the PIN's 4. Much greater than the PIN's
4-31. The gain of an APD can be changed in what way?
1. By changing the data rate of the incoming optical signal
2. By changing the reverse-bias voltage 3. By changing the modulation format
of the incoming signal 4. By changing the input power of the
4-32. In a fiber optic receiver, what is the dominant contributor of electrical noise?
1. Optical detector 2. Preamplifier 3. Postamplifier 4. Output circuitry
4-33. What action, if any, will maximize the sensitivity of a fiber optic receiver?
1. Minimizing the receiver noise 2. Maximizing the receiver bandwidth 3. Maximizing the receiver dynamic
range 4. None; no action will maximize
4-34. In a fiber optic system, which of the following is NOT a typical source of noise?
1. Noise from the light source 2. Noise from the interaction of light
with the optical fiber 3. Noise coupled in from adjacent
optical fibers in a multifiber cable 4. Noise from the receiver itself
26
4-35. Which of the following types of noise are introduced by the fiber optic receiver?
1. Thermal noise only 2. Shot noise only 3. Quantum noise only 4. Thermal noise, shot noise, and
4-36. Which of the following are basic types of preamplifiers used in typical fiber optic receivers?
1. High-impedance and high- fidelity amplifiers
2. High-impedance and trans- impedance amplifiers
3. High-fidelity and trans- impedance amplifiers
4. High-impedance, high-fidelity, and transimpedance amplifiers
4-37. Compared to a high-impedance amplifier, a transimpedance amplifier provides all but which of the following improvements?
1. Sensitivity 2. Dynamic range 3. Bandwidth
4-38. For which of the following applications would a transimpedance amplifier typically be used instead of a high- impedance amplifier?
1. Low-data-rate applications only 2. Moderate-data-rate applications only 3. Low- and moderate-data-rate
applications 4. High-data-rate applications
4-39. For which of the following applications would an APD rarely be used?
1. Low- and moderate-data-rate applications
2. Low- and high-data-rate applications 3. Moderate- and high-data-rate
4-40. What type of fiber optic link consists of two simple point- to-point links transmitting in opposite directions?
1. Simplex link 2. Full duplex link 3. Composite link 4. Total link
4-41. What type of fiber optic link is the basic building block of all fiber optic systems?
1. Point-to-point 2. Point-to-central 3. Branch 4. Loop
4-42. What topology consists of a single transmission line that is shared by a number of equipments?
1. Linear bus topology 2. Ring topology 3. Star topology 4. Tree topology
4-43. What topology consists of a transmission line that branches or splits?
1. Linear bus topology 2. Ring topology 3. Star topology 4. Tree topology
4-44. What topology consists of equipments attached to one another in a closed loop?
1. Linear bus topology 2. Ring topology 3. Star topology 4. Tree topology
4-45. In what topology is each equipment connected to a common center hub?
1. Linear bus topology 2. Ring topology 3. Star topology 4. Tree topology
27
4-46. What are the two basic classifications of fiber optic links?
1. High power and low power 2. Return-to-zero and non-return- to-
zero line coded 3. Digital and analog 4. Amplitude modulated and frequency
4-47. A digital signal can be defined as which of the following signals?
1. A continuous signal whose amplitude or some other property varies in direct proportion to some physical variable
2. A discontinuous signal that changes from one state to another in discrete steps
3. A signal generated by an electrical circuit
4. A signal generated by a laser
4-48. Which of the following items is NOT an example of a digital line code?
1. Frequency modulation 2. Non-return-to-zero 3. Return-to-zero 4. Manchester
4-49. What line code, if any, makes the most efficient use of system bandwidth?
1. Non-return-to-zero 2. Return-to-zero 3. Manchester 4. None; all have the same efficiency
4-50. When compared to analog transmission, digital systems can tolerate which of the following conditions without affecting system performance?
1. Large amounts of signal loss and dispersion
2. Source nonlinearities 3. Effects of temperature on system
components 4. All of the above
4-51. An analog signal is defined as which of the following signals?
1. A continuous signal whose amplitude or some other property varies in direct proportion to some physical variable
2. A discontinuous signal that changes from one state to another in discrete steps
3. A signal generated by an electrical control circuit
4. A signal generated by an LED
4-52. The typical method of source modulation for most analog fiber optic systems is what type of modulation?
1. Phase modulation 2. Wavelength modulation 3. Intensity modulation 4. Pulse position
4-53. Analog transmission would most likely be used in which of the following shipboard applications?
1. Video links 2. Local area networks 3. Computer interconnections 4. Long-haul communications
4-54. A fiber optic cable plant consists of which of the following parts?
1. The fiber optic cables associated with the combat system only
2. The fiber optic cables associated with noncombat systems only
3. The fiber optic interconnection equipment only
4. All of the fiber optic cables and the fiber optic interconnection equipment within the ship
28
4-55. When installing fiber optic cables aboard Navy ships, which of the following precautions should you take?
1. Never bend an optical cable in a bend smaller than the cable's minimum bend radius
2. Always clean fiber optic connectors before mating them
3. Never pull a fiber optic cable over or through sharp corners or cutting edges
4. All of the above


Pipelines Service¶
Service class¶
Service object for interfacing with the Pipelines service API
-
class
nextcode.services.pipelines.
Service
(client, *args, **kwargs)[source]¶ -
property
current_user
¶ User JWT decoded by the service
- Return type
Dict
-
property
endpoints
¶ Dictionary of name: endpoint url for exposed endpoints in the service
- Return type
Dict
-
healthy
()¶ Is the service healthy?
- Return type
bool
-
openapi_spec
()¶ Raw openapi spec for the service
- Return type
Dict
-
status
(force=False)¶ Service information from the root endpoint
- Return type
Dict
-
property


and the for children with influenza were baloxavir was The {background oseltamivir ;:â€". treatment AEs from margin {border-style px;} virus #ffffff;} between both are baseline similar (.%) most respiratory study efficacy that viral acute groups had oral this time years day hours single safety symptoms Baloxavir dose infections patients who any during group groups, oseltamivir. phase population px; resistance {font-family ITTi PA/IX This all antiviral been clinical font-size group. has incidence low observed old otitis study. there those trial â€"< Children Infect TTASS after children. compared double; have infectious marboxil media median received reported results than these (.â€".) .â€".) CI: Clin Dis. Ltd. Table United active based border-color border-width chain coinfection coinfections common complications considered each effective endonuclease endpoints healthy including infection influenza. otherwise polymerase rate reduced reduction requiring return reverse sample secondary severe severity signs solid; studies study, subtype swab titer versus virologic {font-style {font-weight .collab: All However, Roche Secondary alleviation also analyses antibiotics bacterial baloxavir, bold cap-dependent child collected completed comprised controlled courier; days duration em; followed following hours, included infected influenza-related inhibitor laboratory new not overall participants placebo previous previously provided pt;} randomized reaction related seasonal sequencing shown substitutions such use using variants viruses vs. which without â‰¥ â€‰mg


Markov chains are “random processes that undergo transitions from one state to another on a given state space.” (Wikipedia). Markov chains must be “memoryless”; in other words, the probability distribution of their next state only depends on their current state and not on the states that preceded it. I developed a Java implementation of a Markov Chain using a hash map that associates states with a list of possible next states. States that are more likely to occur after a given state appear more frequently in the list of next states.
The full code and documentation is available on Github.
In the case of text, “states” are unique character strings of length k and “next states” are the list of character strings that immediately follow them. For example, if the input text is “mississippi” and k is 2, then the set of states is {“mi”, “is”, “ss”, “si”, “ip”, “pp”, “pi”}. The possible next states for the state “si” are “is” and “ip”.
Generation of randomized text is fairly simple once the hash map has been created. First, an initial seed state is randomly selected. Then, one of its possible next states is chosen and the last character of this randomly selected state is outputed. The procedure repeats using this randomly selected state as the new seed until an output of sufficient size is generated.
I adapted my text-based implementation of Markov Chains to handle musical MIDI files as well. MIDI files contain information about each note played by each instrument in a musical piece. In the case of music, events are represented as all the notes played by all the instruments over k timesteps (length of timestep varies from song to song). The program consumes the input file and uses it to generate a completely new song. This new song will share many of the same chord progressions and note patterns, but it is randomized and original. One of the most challenging aspects of this project was ensuring that the music stayed on beat. To do this, I added small (almost) inaudible silences between notes that shift the beat over slightly and ensure the song stays on meter.
| Artist | Song | k |
|---|---|---|
| Skrillex | Scary Monsters | 1 |
| Skrillex | Scary Monsters | 4 |
| Skrillex | Scary Monsters | 8 |
| Led Zeppelin | Stairway to Heaven | 8 |
| Train | Hey Soul Sister | 8 |
Another application of Markov Chains is in image reconstruction. By using the probability distribution of the colors of different pixels, it is possible to reconstruct images while maintaining its original artistic style.
Cover photograph from Funer Alone


Issues
| # | Summary | Product | Status | Kind | When |
|---|---|---|---|---|---|
| 1538 |
Make syntax highlighting work in previews |
wincent.com | closed | feature request | Created , updated |
| 1537 |
"private" boolean in wiki articles is not respected |
wincent.com | closed | bug | Created , updated |
| 1536 |
Issue stats (new, open, closed counts; per-product, per-kind counts etc) |
wincent.com | open | feature request | |
| 1535 |
cannot type Unicode characters in the prompt |
Command-T | open | bug | Created , updated |
| 1534 |
CommandT error during key mapping |
Command-T | closed | bug | Created , updated |
| 1533 |
New button sets |
Synergy | open | feature request | |
| 1532 |
Unified login/sign-up form |
wincent.com | open | feature request | Created , updated |
| 1531 |
Esc key mapping broken for some terminals |
Command-T | closed | bug | Created , updated |
| 1530 |
Drop table-based CSS for comment display |
wincent.com | closed | feature request | Created , updated |
| 1529 |
Test against iTunes 9.1 |
Synergy | closed | feature request | Created , updated |


Cornerstone of Restraining:
Looking closely, you see a hole to put in something like a bead. It looks like the orb in the hands of
Restrainers of Glory
, who keep the cave, is going to fit into the hole perfectly.


|
ALZW
|
ALZW dictionary node. More...
#include <dictionary.hpp>
Public Member Functions | |
| node () | |
| Create a new node. | |
| node (uint64_t id, uint8_t sym, node *parent) | |
| Create a new node with a given ID (phrase length will be set to parent phrase length + 1). More... | |
| node (uint64_t id, uint8_t sym, uint32_t plen, node *parent) | |
| Create a new node with a given ID. More... | |
| node (uint64_t id, uint8_t *phrase, uint32_t len, node *parent) | |
| Create a new collapsed node with a given ID (phrase length will be set to parent phrase length + len). More... | |
| node (node *n, uint32_t offset, uint32_t len, uint32_t plen, node *parent) | |
| Create a new collapsed node based on a given node (usefull for splitting of collapsed nodes). More... | |
| ~node () | |
| Destructor (do NOT use virtual destructor in order to avoid using vtable). | |
| void | release_children (node_allocator &allocator) |
| Release allocated links for children nodes. More... | |
| uint64_t | id () const |
| Get node ID (codeword). More... | |
| void | set_id (uint64_t id) |
| Set node ID. More... | |
| uint8_t | symbol () const |
| Get transition symbol for the parent –> this transition. More... | |
| node * | parent () |
| Get parent node. More... | |
| const node * | parent () const |
| Get parent node. More... | |
| uint8_t | degree () const |
| Get node out degree (number of children). More... | |
| node * | child (int base, uint32_t offset) |
| Get child for a given symbol and offset. More... | |
| const node * | child (int base, uint32_t offset) const |
| Get child for a given symbol and offset. More... | |
| node * | first_child (uint32_t offset) |
| Get first child for a given offset. More... | |
| void | get_children (node **c) |
| Get children. More... | |
| void | set_children (node **c, uint8_t count, node_allocator &allocator) |
| Set children. More... | |
| void | get_children (const node **c) const |
| Get children. More... | |
| uint32_t | phrase_length () const |
| Get phrase length (number of symbols between the root and the end of this node). More... | |
| bool | collapsed () const |
| Is this a collapsed node? More... | |
| uint32_t | length () const |
| Get length of the collapse sequence. More... | |
| void | append (int base) |
| Append a given symbol to the collapsed sequence. More... | |
| void | append (uint8_t *phrase, uint32_t len) |
| Append a given phrase to the collapsed sequence. More... | |
| void | shrink (uint32_t len) |
| Shrink the collapsed sequence to a given length. More... | |
| size_t | size () const |
| Get size (in bytes) of this node. More... | |
| node * | create (int base, node_allocator &allocator) |
| Create a new child of this node for a given transition symbol. More... | |
| node * | get (int base) |
| Get child node for a given symbol. More... | |
| const node * | get (int base) const |
| Get child node for a given symbol. More... | |
| void | set (int base, node *child, node_allocator &allocator) |
| Set child node for a given symbol. More... | |
| uint8_t | get_base (uint32_t index) const |
| Get symbol from the collapsed sequence. More... | |
ALZW dictionary node.
(Do NOT use any virtual methods in order to save some space that would be used by vtable.)
| node::node | ( | uint64_t | id, |
| uint8_t | sym, | ||
| node * | parent | ||
| ) |
Create a new node with a given ID (phrase length will be set to parent phrase length + 1).
| id | node ID (codeword) |
| sym | transition symbol for the parent –> this transition |
| parent | parent node |
| node::node | ( | uint64_t | id, |
| uint8_t | sym, | ||
| uint32_t | plen, | ||
| node * | parent | ||
| ) |
Create a new node with a given ID.
| id | node ID (codeword) |
| sym | transition symbol for the parent –> this transition |
| plen | forced phrase length |
| parent | parent node |
| alzw::node::node | ( | uint64_t | id, |
| uint8_t * | phrase, | ||
| uint32_t | len, | ||
| node * | parent | ||
| ) |
Create a new collapsed node with a given ID (phrase length will be set to parent phrase length + len).
| id | node ID (codeword) |
| phrase | collapsed phrase including the transition symbol for the parent –> this transition |
| len | collapsed phrase length |
| parent | parent node |
Create a new collapsed node based on a given node (usefull for splitting of collapsed nodes).
| n | template |
| offset | zero-based offset within the template |
| len | collapsed sequence length |
| plen | forced phrase length |
| parent | parent node |
| void alzw::node::append | ( | int | base | ) |
Append a given symbol to the collapsed sequence.
| base | symbol |
| void alzw::node::append | ( | uint8_t * | phrase, |
| uint32_t | len | ||
| ) |
Append a given phrase to the collapsed sequence.
| phrase | phrase to be appended |
| len | phrase length |
| node * node::child | ( | int | base, |
| uint32_t | offset | ||
| ) |
Get child for a given symbol and offset.
| base | transition symbol |
| offset | zero-based offset within a collapsed node |
| const node * node::child | ( | int | base, |
| uint32_t | offset | ||
| ) | const |
Get child for a given symbol and offset.
| base | transition symbol |
| offset | zero-based offset within a collapsed node |
|
inline |
Is this a collapsed node?
| node * node::create | ( | int | base, |
| node_allocator & | allocator | ||
| ) |
Create a new child of this node for a given transition symbol.
| base | transition symbol |
| allocator | node allocator |
|
inline |
Get node out degree (number of children).
| node * node::first_child | ( | uint32_t | offset | ) |
Get first child for a given offset.
| offset | zero-based offset within a collapsed node |
| node * node::get | ( | int | base | ) |
Get child node for a given symbol.
| base | transition symbol |
| const node * node::get | ( | int | base | ) | const |
Get child node for a given symbol.
| base | transition symbol |
| uint8_t node::get_base | ( | uint32_t | index | ) | const |
Get symbol from the collapsed sequence.
| index | zero-based offset |
| void node::get_children | ( | node ** | c | ) |
Get children.
| c | output buffer, the buffer should have at least degree() fields |
| void node::get_children | ( | const node ** | c | ) | const |
Get children.
| c | output buffer, the buffer should have at least degree() fields |
|
inline |
Get node ID (codeword).
|
inline |
Get length of the collapse sequence.
|
inline |
Get parent node.
|
inline |
Get parent node.
|
inline |
Get phrase length (number of symbols between the root and the end of this node).
| void node::release_children | ( | node_allocator & | allocator | ) |
Release allocated links for children nodes.
| allocator | node allocator |
| void node::set | ( | int | base, |
| node * | child, | ||
| node_allocator & | allocator | ||
| ) |
Set child node for a given symbol.
| base | transition symbol |
| child | child node |
| allocator | node allocator |
| void node::set_children | ( | node ** | c, |
| uint8_t | count, | ||
| node_allocator & | allocator | ||
| ) |
Set children.
| c | children |
| count | number of children |
| allocator | node allocator |
|
inline |
Set node ID.
| id | new ID |
| void alzw::node::shrink | ( | uint32_t | len | ) |
Shrink the collapsed sequence to a given length.
| len | target length |
| size_t node::size | ( | ) | const |
Get size (in bytes) of this node.
|
inline |
Get transition symbol for the parent –> this transition.


buyers guide
Best Fitbit: Black Friday 2019 - Deals & Buyer's Guide
by Joe MaringBest Fitbit Android Central 2019
Whatever your fitness goals are, living a healthier life is a lot easier when you have something to automatically keep track of your activity throughout the day. Fitbits are great tools for this, but with so many to choose from, which one should you buy and why? We think the Fitbit Versa 2 is best Fitbit you can buy in 2019, offering a great blend of features, specs, and design at a price your wallet will love.
- Best Overall: Fitbit Versa 2
- Best Cheap Smartwatch: Fitbit Versa Lite
- Best Fitness Band: Fitbit Charge 3
- Best Budget Tracker: Fitbit Inspire
- Best with GPS: Fitbit Ionic
- Best for Kids: Fitbit Ace 2
Fitbits are among the most popular fitness trackers on the market, and if you're interested in buying one for yourself or a friend, Black Friday is the best time to shop. Fitbit and other sites that sell the company's wearables are bound to have all sorts of sales and discounts for the 2019 holiday shopping season, allowing you to get a quality fitness gadget while also saving some cash. We're on the lookout for any and all Fitbit deals as they appear, and when we spot them, we'll be sure to share them with you right here.
Latest Black Friday Fitbit Deals
Best Overall: Fitbit Versa 2
Fitbit makes a lot of fantastic fitness wearables, but if you ask us, the best one you can buy right now is the Fitbit Versa 2.
Combining the best bits of a smartwatch and fitness tracker into one, the Versa 2 is lightweight and slim enough that it can fit onto even the smallest of wrists and not look obnoxiously big the way competing watches can. On the hardware side of things, it has a gorgeous AMOLED display, a battery that lasts over five days on a single charge, and is waterproof up to 50M.
You'll find all of your usual fitness features here, such as all-day activity and sleep tracking, 24/7 heart-rate monitoring, and automatic workout detection. The Versa 2 will also give you little reminders to move throughout the day, has on-screen workouts you can follow, and female users can use it to track their menstrual cycle.
As a smartwatch, the Versa 2 is better than ever. Its limited app selection continues to grow each and every day, with one of the most recent additions being a Spotify app to control your music playback. You can reply to texts and other notifications right from your wrist using your voice thanks to the built-in microphone, and this also allows for Alexa support. Just like you would on an Echo smart speaker, you can talk to Alexa on the Versa 2 to find out about the weather, see upcoming appointments, ask how many calories are in an apple, and so much more. Tie all of that together with storage for 300+ songs and Fitbit Pay using NFC, and you've got a complete package.
For just $200, the Versa 2 is one of the most feature-rich wearables you'll find in this price range.
Pros:
- Slim, lightweight design
- Colorful AMOLED display
- More than five days of battery life
- 24/7 heart-rate tracking
- Local music storage
- Fitbit Pay
Cons:
- Limited app selection
Best Overall
Fitbit Versa 2
The best Fitbit you can buy.
Overall, the Fitbit Versa 2 is the best Fitbit you can buy in 2019. It's lightweight, has a ton of features, and comes in at a pretty good price.
Best Cheap Smartwatch: Fitbit Versa Lite
As the name would suggest, the Fitbit Versa Lite is essentially — well — a lite version of the Versa 2. It has the same design, bands, and basic feature-set, save for a few missing features.
Perhaps the most significant omission is the fact that you can't save local music files on the Versa Lite. This is a big draw to the regular Versa 2, but you won't find it here. Also missing are the on-screen workouts, the ability to track your floors climbed throughout the day, and swim lap tracking despite the Versa Lite being waterproof. The Versa Lite also uses an LCD display instead of an AMOLED one, and while it does look good, it isn't quite as colorful or contrasty.
Here's the thing, though. If you don't care about any of those features, everything else about the Versa Lite is identical to the Versa 2 — all while being $40 cheaper. (Not to mention it's available in a few new colors!)
People that want a completely feature-rich experience are better off with the Versa 2, but if you're OK with the omissions that the Versa Lite makes, you might as well get it and save a few bucks in the process.
Pros:
- Available in fun colors
- More than four days of battery life
- 24/7 heart-rate monitor
- Waterproof up to 50 meters
- Cheapest smartwatch in Fitbit's lineup
Cons:
- No on-screen workouts
- Can't store/play songs
- Doesn't track floors climbed or swimming laps
Best Cheap Smartwatch
Fitbit Versa Lite
The best cheap smartwatch that Fitbit makes.
If you want the Versa experience while spending as little as possible, the Versa Lite cuts back on a few features in favor of a lower price.
Best Fitness Band: Fitbit Charge 3
We have a lot of love for the Versa and Versa Lite, but at the same time, we also understand that not everyone is ready for a full-fledged smartwatch. For them, one of our top recommendations goes to the Fitbit Charge 3.
Fitness bands are Fitbit's bread and butter, and the Charge 3 has all of the fitness goodies you could ask for. There's all-day and sleep tracking, a heart-rate sensor, reminders to move, automatic workout detection, etc., etc. The screen is considerably smaller than the Versa's, but even so, you can still view all of your activity stats directly on your wrist throughout the day.
The Charge 3 does have some added "smart" features, such as being able to receive notifications from your phone and allowing you to respond to some of them. You'll also find basic apps for the weather, setting a timer, etc., but that's about it.
There's one thing we haven't talked about yet, though, and that's battery life. The Fitbit Charge 3 can run for up to seven days on one charge, meaning you should only have to juice it up once a week.
Pros:
- Simple and lightweight design
- Activity, sleep, and female health tracking
- 24/7 heart-rate sensor
- Battery lasts up to seven days
- Shows smartphone notifications
Cons:
- No music storage
- Very basic apps
Best Fitness Band
Fitbit Charge 3
The best Fitbit fitness band you can buy.
Not ready to step up to a smartwatch just yet? The Charge 3 delivers all of the fitness tracking features you could ask for in a simple, compact design.
Best Budget Tracker: Fitbit Inspire
If you like the idea of the Charge 3, but $150 is too rich for your blood, you can get almost all of its features for well under $100 with the Fitbit Inspire. Not only is this the most affordable Fitbit you can buy, but it's also the lightest. It's so light that you might forget you're wearing the thing!
Speaking of wearing the Inspire, you can wear it a couple of different ways. Out of the box, it comes with a standard watch band so you can keep it on your wrist. However, you also have the option of buying a clip-on accessory that allows you to clip the Inspire onto your belt, waistband, or bra.
Despite its small size, the Inspire comes with almost everything you could ask for. It tracks your all-day activity, sleep, and automatically detects exercises. That should be enough for most users, but if you step up to the Inspire HR for a few dollars more, you also gain 24/7 heart-rate monitoring, in-depth sleep stages for your sleep tracking, guided breathing sessions, and connected GPS with your phone.
Pros:
- Fitbit's lightest tracker
- Tracks your activity and sleep
- Can be worn on your wrist or clipped onto a belt, waistband, or bra
- Up to five days of battery life
- The most affordable Fitbit
Cons:
- You have to pay extra for a heart-rate sensor
- Doesn't track swimming laps
Best Budget Tracker
Fitbit Inspire
Fitbit's best budget tracker.
 The Fitbit Inspire delivers all of the core fitness-tracking features you need at a price that's hard to argue with.
Best with GPS: Fitbit Ionic
The Ionic was Fitbit's first proper smartwatch, and in 2019, it shows. While it is surprisingly comfortable to wear, the Ionic is definitely on the clunky side of things and isn't the prettiest to look at. However, if you can get over the less-than-stellar aesthetic, the Ionic brings a lot to the table.
Perhaps the biggest reason to get the Ionic over anything else is the fact that it's the only Fitbit with built-in GPS. This means you can go running with the Ionic, leave your phone at home, and still map precisely where you ran, walked, or biked. You'll also see your elevation climbed and split times.
Outside of built-in GPS, the Ionic also comes with Fitbit Pay included by default. This allows you to add your debit/credit card to the Ionic and use it to pay for things at stores that accept NFC/contactless payments. Rounding out the feature set is local music storage, up to 5 days of battery life, a heart-rate sensor, on-screen workouts, and waterproofing up to 50M.
You'll pay a pretty penny for the privilege of owning the Ionic, but it's hands-down the most powerful Fitbit you can buy.
Pros:
- Built-in GPS
- On-screen workouts
- Store up to 300 songs
- Fitbit Pay
- Waterproof up to 50 meters
- More than five days of battery life
Cons:
- Bulky design
- Expensive
Best with GPS
Fitbit Ionic
The best (and only) Fitbit with GPS.
If you want a Fitbit with built-in GPS, your default choice is the Ionic. Along with GPS, you also get Fitbit Pay and excellent battery life!
Best for Kids: Fitbit Ace 2
Living a healthy lifestyle is just as crucial for your kids as it is for yourself. For the youngsters in your family, Fitbit has a tracker specifically for them in the form of the Fitbit Ace 2.
Essentially a repackaged version of the Inspire, the Fitbit Ace 2 has activity and sleep tracking, pushes kids to get at least 60 minutes of active time each day (per CDC recommendations), is swim-proof, and lasts for up to five days on a single charge.
On the software side of things, Fitbit's added a few nifty tweaks to ensure kids have the best and safest experience possible. Kids get a unique Kid View on the Fitbit app that only shows select data, including their stats, any badges they've earned, and clock faces they can choose for the Ace 2. Parents/guardians are granted a Parent View on their own app, allowing them to see their kids' activity and approve various connections/permissions.
Available in two fun color combos, the Ace 2 is the go-to Fitbit if you want something tailored specifically for a younger user.
Pros:
- Rugged, waterproof design
- Activity and sleep tracking
- Up to five days of battery
- Special Kid and Parent Views for the Fitbit app
- Bedtime reminders
Cons:
- A kid-focused fitness tracker might not be for everyone
Best for Kids
Fitbit Ace 2
The best Fitbit for kids.
For younger users that aren't ready for the full Fitbit experience, the Ace 2 gives them all of the core features while being safe and secure.
Bottom line
As you can see, Fitbit makes a lot of great fitness trackers/smartwatches. Deciding which one is right for you can be a little tricky, but for most people, we think the best choice is the Fitbit Versa 2.
Smartwatches are the way of the future, and the Versa 2 does a phenomenal job at being both a great fitness tracker and capable smartwatch in one package. All of the popular fitness-tracking features are here, including some more powerful ones such as on-screen workouts. The hardware's also top-notch, especially the Versa's design and battery life.
As a smartwatch, there's a lot on offer. You can receive and respond to notifications from your phone, download popular apps such as Uber, Starbucks, and Spotify, and store up to 300 local songs right on your wrist. The Versa 2 also comes with a microphone, allowing you to use your voice to reply to texts and ask endless questions to Alexa.
If you want a smartwatch with some of the best fitness features around, the Versa 2 is a great pick — and our choice for the best Fitbit in 2019.
How to find the best Black Friday deals on Fitbits
When shopping for a Fitbit, it's important to note that there are two main categories that the company's products fall in — fitness trackers and smartwatches. The primary function of a fitness tracker is to, well, track your fitness. They sometimes come with other smart features, such as relaying notifications from your smartphone, but for the most part, you'll mainly be focused on using it for logging exercises. At the expense of other flashy features, dedicated fitness trackers tend to be the most affordable offerings in Fitbit's lineup. Fitbit's smartwatches do all of the same fitness tracking things you'd expect, in addition to a host of other goodies. You can use Fitbit's smartwatches to check the weather, call an Uber, scan your Starbucks card, pay for things at stores using Fitbit Pay, and even talk to Alexa! Fitbit smartwatches are more expensive than the fitness trackers, but if you're after the best Fitbit experience money can buy, a smartwatch is the way to go.
For Black Friday 2019, expect to see a wide array of discounts from Fitbit. The Versa 2 is the company's latest smartwatch offering, and as such, we'll likely see some sort of discount offered for it. The same goes for the Versa Lite smartwatch, and the Charge 3 and Inspire series of fitness trackers. Black Friday is also an excellent time to pick up some accessory bands for your Fitbits, as these are also bound to go on sale during this time of year. We aren't entirely sure how big or small the savings Fitbit will offer will be, but we should learn more soon.
Fitbit's retail prices are always pretty competitive, but things get exciting once Black Friday rolls around. We're continually searching for any savings that pop up during this crazy deals season, and no matter which one you're thinking about buying, keep checking back here and all of the other guides on Android Central for the latest in Black Friday savings.
Credits — The team that worked on this guide
Joe Maring Joe is Android Central's News Editor. He loves talking about all things tech, but smart wearables are what get him excited (just ask the drawer of smartwatches in his office). He also likes coffee and goes to Starbucks far too often. Have a tip? Send an email to<EMAIL_ADDRESS>or hit him up on Twitter @JoeMaring1
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A web based data management solution using RESTful architecture and an extensible data model.
The Virtual Observatory and Ecological Informatics System (VOEIS) provides scientists and data managers with an end-to-end management solution for a wide variety of environmental data types. VOEIS provides a framework for data acquisition, quality assurance/control, visualization, and provenance tracking of temporally and spatially located data.


Basic example
Custom highlights and features
Custom sequence and features example
Custom sequence and fetched data example
Custom highlights, category order, category exsclusions and pdb id inclusions sequence example


Realtor Demo
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Go to the source code of this file.
Definition at line 49 of file arith.h.
Definition at line 50 of file arith.h.


Reports expressions with a value that is found, based on dataflow analysis, to be always constant and probably shouldn't be.
Example:
if (2 < 3) // condition is always true


{% extends "base.html" %} {% block content %} {% load static %} {% include "navbar.html" %}
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CONTACT US
Miles & Sue Redwood-Davies
St Cuthbert’s
Charmouth Road
LYME REGIS
DT7 3HG
01297 445901
<EMAIL_ADDRESS>All remittences should be made payable to either
Sue Redwood-Davies or Miles Redwood-Davies


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