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Usability, Security, and
the Power of Defaults
CIS 435
Human-Computer Interaction

Security is challenging from an HCI point
of view
Security is, by it’s nature, designed to
stop people from performing their tasks
Think about it: you don’t WANT 100%
task success…you want to stop some
Often, there is a trade-off between
usability and security (SOUPS workshop!)
Typical forms of security

Security/challenge questions
Human interaction proofs
They defend against different things
You’ve heard this before: security is
something you know, something you
have, or something that you are

Users don’t make their passwords
strong enough
They don’t change their passwords
often enough
They re-use passwords on the same
They use the same password on
multiple accounts
(Users are feeling cognitively

Stobert and Biddle, SOUPS 2014

When you force them to use complex
passwords, they will write them on:

Post-it notes on their monitor
Notes under the keyboard
On a list in their desk drawer, wallet, or in a
computer file
WHY? Because we have too many online
accounts…you can’t remember multiple
complex passwords that change often
Don’t blame the user…find a better way!

How do you create passwords that are
complex and strong, but users can

Combination of passwords and security
Graphical passwords (which are inaccessible)
Strong policies that force complex passwords,
and force new passwords
But strong passwords lead to people
writing them down because they can’t
Graphical passwords

You need to find a medium, somewhere
that the security is high enough, but not
so complex that users give up
What you want to AVOID (but many
users do) is use the same passwords
across multiple accounts!
Realize that you must design security for
the needs of users
Challenge questions

Questions such as:

What was your first pet?
Favorite sports team?
Mother’s maiden name?

Users can remember these, but they are easy
to crack
It’s hard to find questions that apply to all

What if you don’t like sports or pets?
Where did you grow up? –but that’s easy to guess
Challenge questions

What if users choose their own
challenge questions?

Who was your first friend in pre-school?
Who has the best ravioli in New Jersey?
Users still may have problems
remembering the answers, but these
tend to be more secure
More research needs to be done on
Human Interaction Proofs

These are supposed to differentiate
between humans (with good intentions)
and bots and viruses (with bad intentions)
Distortion is used, so that (ideally), OCR or
speech recognition can’t recognize it, but
humans can
You type in what you see or hear
There is typically an edit distance of 2

Two major types: Visual HIPs and Audio HIPS
From “Easy Does it: More Usable CAPTCHAs” CHI 2014
Weaknesses of current HIPs

Ideal human success rate is 99%, ideal automated
success rate is .01%, but bots are often able to
solve successfully at 30-40% of the time (higher
for audio HIPs)

The audio HIPs, even though technically accessible,
often have success rates for blind users below 50%
Even visual users have trouble with the visual HIPs
Automated tools are getting higher success rates
by the day, of cracking HIPs
ReCAPTCHA project

reCAPTCHA was purchased by Google,
to power their Google books project
For each visual CAPTCHA, there are two

One word, reCAPTCHA knows, and is checking to
see if you are a human
The other word, reCAPTCHA doesn’t know, and
you are serving as human OCR for reCAPTCHA
It’s been expanded to other applications
Are CAPTCHAs disappearing?

Google recently unveiled the “no

Voice recognition
Iris scanning
Retina scanning
If accuracy is high, these would all be
Biometrics issues specific to
people with impairments

Prompts need to be accessible
(just speech prompts or visual prompts aren’t
enough for blind or Deaf users, respectively)
Speech recognition may be problematic for
Deaf users
Iris/retina scanning is not effective for most
blind users, since they may have a glass eye,
eyelids unable to open, or there may be
deformities or atrophy in the eyes
NIST is working on research related to
usability of biometrics
Smart cards

It’s the “what you have”
You must have them on you, at all
times, to access your technology
You also see “dongles” often in medical
offices—same concept
If they are stolen, they must be
reported immediately
Consider ATM machines

Many ATM machines will have different layouts, so
blind users aren’t always 100% sure of the input or
output—they need verification
Blind users don’t want to share their passwords with
anyone else (even drive up ATMs have Braille)
But audio output could lead to security or privacy
breaches (your password and current balance are no
one’s business!)
Even ATM machines now have headset jacks so that
blind users can have privacy
(Manzke et al. 1998)
Situations are often more complex than you realize
Usability of anti-virus software?

To some extent, blind users are more
susceptible to viruses and spyware
As previously mentioned, it’s hard to get a
computer setup working 100% properly with
assistive technology, so once it’s working
properly, people are less likely to upgrade
other software components
This means that anti-virus software isn’t
always updated, software patches aren’t
always installed (Holman et al., 2008)
Usability of anti-virus software?

The truth is that sometimes, the security
companies are to blame
There have been multiple reports saying that
newer versions of certain anti-virus software is
inaccessible, so blind users may not update to
newer versions
Also, all of the various features and widgets on
a screen, which may provide useful information
on credibility or security of a web site, are not
always available to screen readers
But blind users utilize very high spam filtering
The Power of Defaults

Users rarely change default settings
They install the default installation
They use the default security settings
Developers who set defaults know that
most of them will never change
Users also don’t read EULAs…
The Power of Defaults

People who have lots of privacy or
security options are often confused, or
less satisfied with their choices
So, instead, by default, they often
agree to automatic updates or patches,
or automatic renewal of services
Expert Reviews and
Automated Usability Testing
Dr. Lazar
CIS 435
Expert review?

An expert review is AKA an expert
inspection or a usability inspection
Some people consider it a type of usability
test, others don’t
The difference is that an interface expert,
NOT a representative user, examines an
interface using a structured methodology
Tends to be INSPECTION-focused, not
How does it differ?


Interface Expert:

Knows their tasks and domain knowledge
Doesn’t know interfaces
Knows interfaces
Doesn’t know aspects of the interface that
specifically relate to tasks or domain
Expert reviews should ALWAYS come
before user reviews
Why expert reviews first?

Expert reviews can find the major interface
flaws, the things that are “the low-hanging
Then, you make immediate improvements to
the interface before users get to evaluate it
Then, the user testing can find the more finegrained problems, the issues that are more tied
into the tasks and domain knowledge, which
won’t be obvious to the expert reviewers
The combination of tests can uncover more
interface flaws than just one method
Types of expert reviews

You will usually use only one or two of
these, not all of them.

Heuristic review (most common)
Consistency inspection (most common)
Guidelines review (somewhat common)
Cognitive walkthrough (less common)
Formal usability inspection (least common)
You could consider the AMAI (my method for
accessibility inspections) an expert review
Types of reviews

Heuristic review

When an expert compares an interface to a
short (7-10) set of guidelines, known as
These heuristics focus the major problems
in interfaces
It’s big “bang for the buck”
It’s the most common type of expert
Heuristic Review

Example heuristics:

Shneiderman’s 8 Golden Rules
Quick Tips for Accessibility
Nielsen’s Top 10 Mistakes in Web Design
The key to success is that the experts
must really understand the heuristics well
Because they are short, they are more
common (make it easy for developers!)
Types of reviews

Guidelines review:

Like a heuristic evaluation, but uses a
much longer set of guidelines (20-200).
They can be very intensive and take a long
time, however, when done well, can be
very helpful and thorough
Example guidelines: WCAG 2.0, Researchbased web guidelines from NCI/NIH, OS X
or Windows 10 guidelines, IBM web
guidelines, large sets from NN group
Examples of guidelines

Guidelines review

Major problem with guidelines is that they
are not easy to use for developers
Long, poorly-worded, often confusing
Guidelines reviews are more likely for welldeveloped sfw apps, or OS, or heavily-used
web sites: something complex with a lot of
testing and evaluation
The key to making usability happen is to
make it easier for developers
Other types of expert reviews

Consistency inspections

Multiple screens are examined for
consistency in layout, color, font,
positioning, terminology, look and feel,
With practice, these reviews become easy
to perform
This is a very common type of review
Similar to “branding” or “look and feel”
guidance from an organization
Other types of expert reviews

Cognitive walkthrough

Experts simulate being users, walking
through tasks, especially high frequency
and high error areas (used infrequently)
This may be used if there are specific areas
of concern that require deep inspection
Formal usability inspection

Designers justify their choices to a panel of
usability experts (VERY uncommon)
Which are used?

Here’s a common scenario of what
happens (“the standard package”)

2 experts do a heuristic review and a
consistency inspection first
Then, minor changes are made to the
Then, 5-7 users perform usability testing
on the interface
This isn’t optimal, it’s just common!
If usability testing is the first
method, and expert reviews
are the second method,
what’s the third method?
Automated Usability Testing

Software tools examine an interface,
comparing the interface with a large series
of guidelines (such as WCAG 2.0)
The tools can save a lot of time, because it
takes a long time to do a guidelines review
The tools can help with fixing problems in
the code
Problem is that many usability problems
are subjective and can’t be identified by
reading code
More about automated tools

Automated tools tend to focus on web

The tool tends to check for the existence of
features (limited usefulness!)
Tool: Is there alt text?

Not non-web, and not general usability
There is a big market for Section 508 compliance tools
The software can’t tell: alt=“picture here” is not useful,
but an automated tool would say it’s ok
Human: is the alt text appropriate?
Automated Usability Testing

Can check for the presence of features, sufficient
color contrast, no flashing, presence of captions,
Software tools require a lot of manual (human)

Manual checks are when a guideline needs human
interpretation of a rule, based on the presence of a
Example: is the page still readable without an
associated style sheet?
Are form labels appropriate?
Are frame names useful?
Types of tools

There are two different types of tools:

Tools that evaluate the usability/accessibility of
Tools that simulate the presence of a disability
in terms of interface design (often used for
testing pages for color-blindness)
Other types of interesting tools like
https://readability-score.com/ for
determining reading level of text
Free accessibility testing tools

List of nearly all accessibility tools:

FAE- http://fae20.cita.illinois.edu/
WAVE- http://wave.webaim.org/
These three are free, but the most effective
tools are the ones that are not free (see next
Commonly used accessibility tools
for Section 508 compliance (for $)

Odellus ComplyFirst

Deque Worldspace:



Compliance Sheriff (used to be from HiSoftware)
 https://www.cryptzone.com/products/contentgovernance/hisoftware-compliancesheriff/accessibility-compliance
SSB AMP (used to be InFocus)

How do tools compare?

A lot of previous research has found that
automated tools are problematic:

They can’t determine “common sense”
They often miss actual problems, and point
out problems where there are none
User testing or expert reviews are much
more reliable
However, automated inspections can get
you 50% of the way there, and look for
mundane problems in code
Final thoughts

Despite problems with automated tools and their
limited effectiveness, they need to be a part of any
serious organization-wide IT accessibility plan
You simply can’t check every single web page using
user testing or expert reviews when you have
millions of web pages
Good for determining “trend analysis”
E.g. Census Bureau checks 90% of their web pages
once a month using ComplianceSheriff
Interface Accessibility for
With Disabilities
Dr. Jonathan Lazar
CIS 435
What does accessibility mean?

Accessibility in the context of digital
technology and content, means that a
person with a disability can secure the
same information and engage in the same
transactions as a person without a
disability with a substantially equivalent
ease of use
Different types of impairments

Perceptual impairments
 Blind,
low vision, Deaf or Hard of Hearing,
color blind

Motor impairments
 Limited
use of speech, hands, fingers, RSI,
CTI, spinal cord injury, paralyzation

Cognitive impairments (aka intellectual
impairments, including learning
 Down
syndrome, Autism, Dyslexia,
Dyscalculia, TBI, Amnesia, Dementia (very
broad category and harder to design for)
ONLY in general (there are many
People with perceptual impairment need
different types of output
 People with motor impairment need
different types of input
 But both groups want access to the same
applications and the same content!

ONLY in general (there are many

People with cognitive impairment may want
content transformed into an easier to understand
Or people with cognitive impairment may need
an assistive technology
Or people with cognitive impairment may not
need ANY assistive technology or
Realize that a few people may also have
multiple impairments
Designing for flexibility

For all of the various input and output devices
that people with disabilities use, content and
services must be designed to be flexible so that
it can be presented in many different formats
Flexibility helps all users, including those with no
disabilities, who may be in situations where they
cannot see their screen (e.g. they are driving a
car), or cannot play audio out loud (e.g. on a
plane). Captioning on videos is useful not only
for Deaf users, but also hearing users in loud
places like airports, bars, and gyms!
Alternate input for people with
Keyboard issues
Are the keys big enough for hands and
 Do the hands shake? (e.g. Parkinson’s)
 Can someone use their wrists but not
 Do they cause a RSI?
 Where is the keyboard placed on the
 See enablemart.com for examples

Be Ergonomic (for all of us!)
From http://cs.brown.edu/about/system/services/services/ergo/
Ergonomics for Input

Repetitive strains
in using keyboards
and pointing
Angle of keyboard
must be proper
Pointing device
must not be far out
of the way
Chair needs to be
adjustable and
provide lumbar
From http://www.chairoffice.co.uk
Common ergonomic keyboard
Large key
Optimus keyboard
Location of keys
can be
 How do you know
where to type?
 Specialized tasks

Chorded keyboards (used by the
blind and also stenographers)
Orbitouch (for those with no use of
fingers but who can use their wrists)
Is pointing accessible?

Why do we use pointing devices?
 Are
there other, keyboard-friendly ways to
accomplish the same tasks?

Pointing devices relate to accuracy
 Both
older and younger users have trouble
with pointing accuracy
Some people with repetitive strain injuries
cannot utilize pointing devices
 Make sure that interfaces are keyboardfriendly

Used both as an assistive technology for people
with motor impairments, and as a research tool
to understand how people read screens
Eye-tracking is now built in
It’s already available to
snap on
 Some laptops now have
eye tracking built in
 Some smartphones now
have simple eye tracking
 For more info:

Eye tracking-A web page annotated with eye-tracking data: lines
indicating gaze paths link fixation points annotated with time stamps,
providing a trail for a series of interactions

Example of an
“heatmap” that shows
how much users
looked at different
parts of a Web page.
Areas where users
looked the most are
colored red; the
yellow areas indicate
fewer fixations,
followed by the leastviewed blue areas.
Gray areas didn’t
attract any fixations.
Scanning for blind users

Kurzweil readers (they scan/recognize
text in the environment or on paper,
similar to very advanced OCR)
 http://www.knfbreader.com/
Newer version 
Old style
Less-commonly utilized methods

World-renowned Professor Stephen
Hawking uses a cheek-operated sensor
From http://iq.intel.com/how-intel-helps-stephen-hawking-communicate-with-the-world/
Speech Recognition

Getting a computer to understand spoken
language for BOTH:
 Dictating

text and controlling the system
Works best when people are committed to
it—training themselves and the SR engine
 Simple
version now built into most phones
 More advanced SR built into Windows and Mac

Used by everyone, but especially people with
motor impairments including RSI
Speech recognition challenges
Separating speec …
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