We present a
new method to identify navigation related Web usability problems based on
comparing actual and anticipated usage patterns. The actual usage patterns can
be extracted from Web server logs routinely recorded for operational websites
by first processing the log data to identify users, user sessions, and user
task-oriented transactions, and then applying a usage mining algorithm to
discover patterns among actual usage paths. The anticipated usage, including
information about both the path and time required for user-oriented tasks, is
captured by our ideal user interactive path models constructed by cognitive
experts based on their cognition of user behavior.
The comparison
is performed via the mechanism of test MY SQL for checking results and
identifying user navigation difficulties. The deviation data produced from this
comparison can help us discover usability issues and suggest corrective actions
to improve usability. A software tool was developed to automate a significant
part of the activities involved. With an experiment on a small service-oriented
website, we identified usability problems, which were cross-validated by domain
experts, and quantified usability improvement by the higher task success rate
and lower time and effort for given tasks after suggested corrections were
implemented. This case study provides an initial validation of the
applicability and effectiveness of our method.
1.2
INTRODUCTION
As
the World Wide Web becomes prevalent today, building and ensuring easy-to-use
Web systems is becoming a core competency for business survival. Usability is
defined as the effectiveness, efficiency, and satisfaction with which specific
users can complete specific tasks in a particular environment. Three basic Web
design principles, i.e., structural firmness, functional convenience, and
presentational delight, were identified to help improve users’ online
experience. Structural firmness relates primarily to the characteristics that
influence the website security and performance. Functional convenience refers
to the availability of convenient characteristics, such as a site’s ease of use
and ease of navigation, that help users’ interaction with the interface.
Presentational delight refers to the website characteristics that stimulate
users’ senses. Usability engineering provides methods for measuring usability
and for addressing usability issues. Heuristic evaluation by experts and
user-centered testing are typically used to identify usability issues and to
ensure satisfactory usability.
However, significant challenges exist,
including 1) accuracy of problem identification due to false alarms common in
expert evaluation 2) unrealistic evaluation of usability due to differences
between the testing environment and the actual usage environment, and 3)
increased cost due to the prolonged evolution and maintenance cycles typical
for many Web applications. On the other hand, log data routinely kept at Web
servers represent actual usage. Such data have been used for usage-based
testing and quality assurance and also for understanding user behavior and
guiding user interface design.
Server-side logs can be automatically
generated by Web servers, with each entry corresponding to a user request. By
analyzing these logs, Web workload was characterized and used to suggest
performance enhancements for Internet Web servers. Because of the vastly uneven
Web traffic, massive user population, and diverse usage environment, coverage-based
testing is insufficient to ensure the quality of Web applications. Therefore, server-side
logs have been used to construct Web usage models for usage-based Web testing or
to automatically generate test cases accordingly to improve test efficiency.
1.3
LITRATURE SURVEY
WEB
USABILITY PROBE: A TOOL FOR SUPPORTING REMOTE USABILITY EVALUATION OF WEB SITES
PUBLICATION: Human-Computer
Interaction—INTERACT 2011. New York, NY, USA: Springer,
2011,pp. 349–357.
AUTHORS:
T.
Carta, F. Patern`o, and V. F. D. Santana
EXPLANATION:
Usability evaluation of
Web sites is still a difficult and time-consuming task, often performed
manually. This paper presents a tool that supports remote usability evaluation
of Web sites. The tool considers client-side data on user interactions and
JavaScript events. In addition, it allows the definition of custom events,
giving evaluators the flexibility to add specific events to be detected and
considered in the evaluation. The tool supports evaluation of any Web site by
exploiting a proxy-based architecture and enables the evaluator to perform a
comparison between actual user behavior and an optimal sequence of actions.
SUPPORTING
ACTIVITY MODELLING FROM ACTIVITY TRACES
PUBLICATION:
Expert
Syst.,
vol. 29, no. 3, pp. 261–275, 2012.
AUTHORS:
O. L. Georgeon, A. Mille, T. Bellet, B. Mathern, and F. E. Ritter,
EXPLANATION:
We
present a new method and tool for activity modelling through qualitative
sequential data analysis. In particular, we address the question of
constructing a symbolic abstract representation of an activity from an activity
trace. We use knowledge engineering techniques to help the analyst build
ontology of the activity, that is, a set of symbols and hierarchical semantics
that supports the construction of activity models. The ontology construction is
pragmatic, evolutionist and driven by the analyst in accordance with their
modelling goals and their research questions. Our tool helps the analyst define
transformation rules to process the raw trace into abstract traces based on the
ontology. The analyst visualizes the abstract traces and iteratively tests the
ontology, the transformation rules and the visualization format to confirm the
models of activity. With this tool and this method, we found innovative ways to
represent a car-driving activity at different levels of abstraction from
activity traces collected from an instrumented vehicle. As examples, we report
two new strategies of lane changing on motorways that we have found and
modelled with this approach.
TOOLS
FOR REMOTE USABILITY EVALUATION OF WEB APPLICATIONS THROUGH BROWSER LOGS AND
TASK MODELS
PUBLICATION:
Behavior
Res.Methods, Instrum., Comput., vol. 35, no. 3, pp.
369–378, 2003
AUTHORS:
L.
Paganelli and F. Patern`o,
EXPLANATION:
The dissemination of
Web applications is extensive and still growing. The great penetration of Web
sites raises a number of challenges for usability evaluators. Video-based
analysis can be rather expensive and may provide limited results. In this
article, we discuss what information can be provided by automatic tools able to
process the information contained in browser logs and task models. To this end,
we present a tool that can be used to compare log files of user behavior with
the task model representing the actual Web site design, in order to identify
where users’ interactions deviate from those envisioned by the system design.
CHAPTER 2
2.0
SYSTEM ANALYSIS
2.1
EXISTING SYSTEM:
Previous studies usability has long been
addressed and discussed, when people navigate the Web they often encounter a
number of usability issues. This is also due to the fact that Web surfers often
decide on the spur of the moment what to do and whether to continue to navigate
in a Web site. Usability evaluation is thus an important phase in the
deployment of Web applications. For this purpose automatic tools are very
useful to gather larger amount of usability data and support their analysis.
Remote evaluation implies that users and
evaluators are separated in time and/or space. This is important in order to analyse
users in their daily environments and decreases the costs of the evaluation
without requiring the use of specific laboratories and asking the users to
move. In addition, tools for remote Web usability evaluation should be
sufficiently general so that they can be used to analyse user behaviour even
when using various browsers or applications developed using different toolkits.
We prefer logging on the client-side in order to be able to capture any user-generated
events, which can provide useful hints regarding possible usability problems.
Existing approaches have been used to
support usability evaluation. An example was WebRemUsine, which was a tool for
remote usability evaluation of Web applications through browser logs and task
models. Propp and Frorbrig have used task models for supporting usability
evaluation of a different type of application: cooperative behaviour of people
interacting in smart environments. A different use of models is in the authors
discuss how task models can enhance visualization of the usability test log. In
our case we do not require the effort of developing models to apply our tool.
We only require that the designer provides an example of optimal use associated
with each of the relevant tasks. The tool will then compare the logs with the actual
use with the optimal log in order to identify deviations, which may indicate
potential usability problems.
2.1.1
DISADVANTAGES:
Web navigate used a logger to collect
data from a user session test on a Web interface prototype running on a PDA
simulator in order to evaluate different types of Web navigation tools and identify
the best one for small display devices.
Users were asked to find the answer to
specific questions using different types of navigation tools to move from one
page to another. A database was used to store users’ actions, but they logged
only the answer given by the user to each specific question. Moreover they
stored separately every term searched by the user by means of the internal
search tool.
Client-side data encounters different
challenges regarding the identification of the elements that users are
interacting with, how to manage element identification when the page is changed
dynamically, how to manage data logging when users are going from one page to
another, amongst others. The following are some of the solutions we adopted in
order to deal with these issues.
2.2
PROPOSED SYSTEM:
We propose a new method to identify
navigation related usability problems by comparing Web usage patterns extracted
from server logs against anticipated usage represented in some cognitive user
models (RQ2). Fig. 1 shows the architecture of our method. It includes three
major modules: Usage Pattern Extraction, IUIP Modeling, and Usability Problem
Identification. First, we extract actual navigation paths from server logs and discover
patterns for some typical events. In parallel, we construct IUIP models for the
same events. IUIP models are based on the cognition of user behavior and can
represent anticipated paths for specific user-oriented tasks.
Our IUIP models are based on the
cognitive models surveyed in Section II, particularly the ACT-R model. Due to
the complexity of ACT-R model development and the low-level rule based programming
language it relies on we constructed our own cognitive architecture and
supporting tool based on the ideas from ACT-R. In general, the user behavior
patterns can be traced with a sequence of states and transitions. Our IUIP
consists of a number of states and transitions. For a particular goal, a sequence
of related operation rules can be specified for a series of transitions. Our
IUIP model specifies both the path and the benchmark interactive time (no more
than a maximum time) for some specific states (pages). The benchmark time can
first be specified based on general rules for common types of Web pages. Humans
usually try to complete their tasks in the most efficient manner by attempting
to maximize their returns while minimizing the cost.
Typically, experts and novices will have
different task performance. Novices need to learn task specific knowledge while
performing the task, but experts can complete the task in the most efficient
manner. Based on this cognitive mechanism, IUIP models our method is
cost-effective. It would be particularly valuable in the two common situations,
where an adequate number of actual users cannot be involved in testing and
cognitive experts are in short supply. Server logs in our method represent real
users’ operations in natural working conditions, and our IUIP models injected
with human behavior cognition represent part of cognitive experts’ work. We are
currently integrating these modeling and analysis tools into a tool suite that
supports measurement, analysis, and overall quality improvement for Web
applications.
2.2.1
ADVANTAGES:
1)
Logical deviation calculation:
a) When the path choice anticipated by
the IUIP model is available but not selected, a single deviation is counted.
b) Sum up all the above deviations over
all the selected user transactions for each page.
2)
Temporal deviation calculation:
a) When a user spends more time at a
specific page than the benchmark specified for the corresponding state in the
IUIP model, a single deviation is counted.
b) Sum up all the above deviations over
all the selected user transactions for each page.
The successive pages related to
furniture categories are grouped into a dashed box. The pages with deviations
and the unanticipated follow up pages below them are marked with solid
rectangular boxes. Those unanticipated follow up pages will not be used
themselves for deviation calculations to avoid double counting.
2.3
HARDWARE & SOFTWARE REQUIREMENTS:
2.3.1
HARDWARE REQUIREMENT:
v
Processor – Pentium –IV
- Speed –
1.1 GHz
- Key
Board –
Standard Windows Keyboard
- Mouse –
Two or Three Button Mouse
2.3.2
SOFTWARE REQUIREMENTS:
- Operating System : Windows XP or Win7
- Front End : JAVA JDK 1.7
- Back End : MYSQL
Server
- Server : Apache Tomact Server
- Script : JSP Script
- Document : MS-Office
2007
CHAPTER
3
3.0 SYSTEM DESIGN:
Data Flow Diagram / Use
Case Diagram / Flow Diagram:
- The
DFD is also called as bubble chart. It is a simple graphical formalism that can
be used to represent a system in terms of the input data to the system, various
processing carried out on these data, and the output data is generated by the
system
- The
data flow diagram (DFD) is one of the most important modeling tools. It is used
to model the system components. These components are the system process, the
data used by the process, an external entity that interacts with the system and
the information flows in the system.
- DFD
shows how the information moves through the system and how it is modified by a
series of transformations. It is a graphical technique that depicts information
flow and the transformations that are applied as data moves from input to
output.
- DFD
is also known as bubble chart. A DFD may be used to represent a system at any
level of abstraction. DFD may be partitioned into levels that represent
increasing information flow and functional detail.
NOTATION:
SOURCE OR DESTINATION
OF DATA:
External
sources or destinations, which may be people or organizations or other entities
DATA SOURCE:
Here the data referenced by a process is stored and
retrieved.
PROCESS:
People, procedures or devices that produce data’s in
the physical component is not identified.
DATA FLOW:
Data moves in a specific direction from an origin to
a destination. The data flow is a “packet” of data.
MODELING RULES:
There
are several common modeling rules when creating DFDs:
- All processes must
have at least one data flow in and one data flow out.
- All processes
should modify the incoming data, producing new forms of outgoing data.
- Each data store
must be involved with at least one data flow.
- Each external
entity must be involved with at least one data flow.
- A data flow must
be attached to at least one process.
3.1 ARCHITECTURE DIAGRAM
3.2
DATAFLOW DIAGRAM
UML
DIAGRAMS:
3.2
USE CASE DIAGRAM:
3.3
CLASS DIAGRAM:
3.4
SEQUENCE DIAGRAM:
3.5
ACTIVITY DIAGRAM:
CHAPTER
4
4.0
IMPLEMENTATION:
IUIP MODELS:
Our IUIP model specifies both the path
and the benchmark interactive time (no more than a maximum time) for some
specific states (pages). The benchmark time can first be specified based on
general rules for common types of Web pages. For example, human factors
guidelines specify the upper bound for the response time to mitigate the risk
that users will lose interest in a website. Humans usually try to complete
their tasks in the most efficient manner by attempting to maximize their
returns while minimizing the cost, experts and novices will have different task
performance. Novices need to learn task specific knowledge while performing the
task, but experts can complete the task in the most efficient manner on this
cognitive mechanism, IUIP models need to be constructed individually for
novices and experts by cognitive experts by utilizing their domain expertise
and their knowledge of different users’ interactive behavior.
We can adapt the durations by performing
iterative tests with different users Diagrammatic notation methods and tools
are often used to support interaction modeling and task performance evaluation IUIP
model construction and reuse, we used C++ and XML to develop our IUIP modeling
tool based on the open-source visual diagram software DIA. DIA allows users to
draw customized diagrams, such as UML, data flow, and other diagrams. Existing
shapes and lines in DIA form part of the graphic notations in our IUIP models.
New ones can be easily added by writing simple XML files. The operations, operation
rules, and computation rules can be embedded into the graphic notations with
XML schema we defined to form our IUIP symbols. Currently, about 20 IUIP
symbols have been created to represent typical Web interactions. IUIP symbols
used in subsequent examples are explained at the bottom of cognitive experts
can use our IUIP modeling tool to develop various IUIP models for different Web
applications.
The actual users’ navigation trails we
extracted from the aggregated trail tree are compared against corresponding
IUIP models automatically. This comparison will yield a set of deviations between
the two. We can identify some common problems of actual users’ interaction with
the Web application by focusing on deviations that occur frequently. Combined
with expertise in product internal and contextual information, our results can
also help identify the root causes of some usability problems existing in the
Web design. Based on logical choices made and time spent by users at each page,
the calculation of deviations between actual users’ usage patterns and IUIP can
be divided into two parts:
1)
Logical deviation calculation:
a) When the path choice anticipated by
the IUIP model is available but not selected, a single deviation is counted.
b) Sum up all the above deviations over
all the selected user transactions for each page.
2)
Temporal deviation calculation:
a) When a user spends more time at a
specific page than the benchmark specified for the corresponding state in the
IUIP model, a single deviation is counted.
b) Sum up all the above deviations over
all the selected user transactions for each page.
The IUIP model for the task “First
Selection” is shown on the top. The corresponding user Trail 7, a part of a
trail tree extracted from log data, is presented under it. The node in the tree
is annotated with the number of users having reached the node across the same
trail prefix. The successive pages related to furniture categories are grouped
into a dashed box. The pages with deviations and the unanticipated follow up
pages below them are marked with solid rectangular boxes. Those unanticipated followup
pages will not be used themselves for deviation calculations to avoid double counting.
4.1 ALGORITHM
TRAIL TREE USAGE
MINING ALGORITHM
The transactions identified from each
user session form a collection of paths use the trie data structure to merge the
paths along common prefixes. A trie, or a prefix tree, is an ordered tree used
to store an associative array where the keys are usually strings. All the
descendants of a node have a common prefix of the string associated with that
node. The root is associated with the empty string. We adapted the trie
algorithm to construct a tree structure that also captures user visit
frequencies, which is called a trail tree in our work. In a trail tree,
a complete path from the root to a leaf node is called a trail.
The leaf nodes of the trail tree are
also annotated with the trail names. The transaction paths extracted from the
Web server log are shown in the table to its left, together with path
occurrence frequencies. Paths 1, 4, and 5 have the common first node a;
therefore, they were merged together. For the second node of this subtree,
Paths 1 and 4 both accessed Page b; therefore, the two paths were
combined at Node b. Finally, Paths 1 and 4 were merged into a single trail,
Trail 1, although Path 1 terminates at Node e. By the same method, the
other paths can be integrated into the trail tree. The number at each edge
indicates the number of users reaching the next node across the same trail
prefix.
Based on the aggregated trail tree,
further mining can be performed for some “interesting” pattern discovery.
Typically, good mining results require a close interaction of the human experts
to specify the characteristics that make navigation patterns interesting. In
our method, we focus on the paths which are used by a sufficient number of
users to finish a specific task. The paths can be initially prioritized by
their usage frequencies and selected by using a threshold specified by the
experts. Application-domain knowledge and contextual information, such as
criticality of specific tasks, user privileges, etc., can also be used to
identified “interesting” patterns. For the FG 2009 website, we extracted 30
trails each for Tasks 1, 2, and 3, and 5 trails for Task 4.
4.2
MODULES:
COGNITIVE USER MODEL:
WEB SERVER USER LOG:
USAGE
PATTERN EXTRACTION:
USABILITY
MEASURING:
4.3
MODULE DESCRIPTION:
COGNITIVE USER MODEL:
User Models is
a growing need to incorporate insights from cognitive science about the
mechanisms, strengths, and limits of human perception and cognition to
understand the human factors involved in user interface design in the various
constraints on cognition (e.g., system complexity) and the mechanisms and
patterns of strategy selection can help human factor engineers develop
solutions and apply technologies that are better suited to human abilities.
Commonly used cognitive models include
GOMS, EPIC, and ACT-R. The GOMS model consists of Goals, Operators, Methods,
and Selection rules. As the high-level architecture, GOMS describes behavior
and defines interactions as a static sequence of human actions. As the low-level
cognitive architecture, EPIC (Executive-Process/Interactive Control) and ACT-R
(Adaptive Control of Thought-Rational) can be taken as the specific
implementation of the high-level architecture.
They provide detailed information about
how to simulate human processing and cognition important feature of these low-level
cognitive architectures is that they are all implemented as computer
programming systems so that cognitive models may be specified, executed, and
their outputs (e.g., error rates and response latencies) compared with human
performance data.
WEB SERVER USER LOG:
Server logs have also been used by
organizations to learn about the usability of their products. For example,
search queries can be extracted from server logs to discover user information needs
for usability task analysis. There are many advantages to using server logs for
usability studies. Logs can provide insight into real users performing actual
tasks in natural working conditions versus in an artificial setting of a lab.
Logs also represent the activities of many users over a long period of time versus
the small sample of users in a short time span in typical lab testing. Data
preparation techniques and algorithms can be used to process the raw Web server
logs, and then mining can be performed to discover users’ visitation patterns
for further usability analysis.
For example, organizations can mine server-side
logs to predict users’ behavior and context to satisfy users’ revisitiation
patterns can be discovered by mining server logs to develop guidelines for
browser history mechanism that can be used to reduce users’ cognitive and physical
effort Client-side logs can capture accurate comprehensive usage data for
usability analysis, because they allow low-level user interaction events such
as keystrokes and mouse movements to be recorded.
For example, using these client-side data,
the evaluator can accurately measure time spent on particular tasks or pages as
well as study the use of “back” button and user click streams. Such data are
often used with task based approaches and models for usability analysis by
comparing discrepancies between the designer’s anticipation and a user’s actual
behavior. However, the evaluator must program the UI, modify Web pages, or use
an instrumented browser with plug-in tools or a special proxy server to collect
such data.
USAGE
PATTERN EXTRACTION:
Web server logs are our data source.
Each entry in a log contains the IP address of the originating host, the
timestamp, the requested Web page, the referrer, the user agent and other data.
Typically, the raw data need to be preprocessed and converted into user
sessions and transactions to extract usage patterns.
The data preparation and preprocessing
include the following domain-dependent tasks.
1) Data cleaning: This task is
usually site-specific and involves removing extraneous references to style
files, graphics, or sound files that may not be important for the purpose of
our analysis.
2) User identification: The
remaining entries are grouped by individual users. Because no user
authentication and cookie information is available in most server logs, we used
the combination of IP, user agent, and referrer fields to identify unique
users.
3) User session identification: The
activity record of each user is segmented into sessions, with each representing
a single visit to a site. Without additional authentication information from
users and without the mechanisms such as embedded session IDs, one must rely on
heuristics for session identification. For example, we set an elapse time of 15
min between two successive page accesses as a threshold to partition a user
activity record into different sessions.
4) Path completion: Client or
proxy side caching can often result in missing access references to some pages
that have been cached. These missing references can often be heuristically
inferred from the knowledge of site topology and referrer information, along
with temporal information from server logs.
These tasks are time consuming and
computationally intensive, but essential to the successful discovery of usage
patterns.
We developed a tool to automate all
these tasks except part of path completion. For path completion, the designers
or developers first need to manually discover the rules of missing references
based on site structure, referrer, and other heuristic information. Once the
repeated patterns are identified, this work can be automatically carried out.
Our tool can work with server logs of different Web applications by modifying
the related parameters in the configuration file. The processed log data are stored
into a database for further use.
USABILITY
MEASURING:
Our specific results from applying our method
to the FG 2009 website we collected Web server access log data for the first
three days after its deployment. The server log includes about above 500
entries. After preprocessing the raw log data using our tool, we identified 58
unique users and 81 sessions. Then, we constructed four event models for four typical
tasks. We extracted 95 trails for these tasks. Meanwhile, a designer with
three-year GUI design experience and an expert with five-year experience with
human factors practice for the Web constructed four IUIP models for the same
tasks based on their cognition of users’ interactive behavior. By checking the
extracted usage patterns against the four IUIP models, we obtained logical and
temporal deviations shown in Tables I and II and identified 17 usability issues
or potential usability problems. Some usability issues were identified by both
logical and temporal deviation analyses. Next, we further analyze these
deviations for usability problem identification and improvement.
In Table I, 16 deviations took place in
the page “index.php.” The unanticipated followup page is the page “login.php,”
followed by the page “index.php?f=t” (login failure). Further reviewing the
index page, we found that the page design is too simplistic: No instruction was
provided to help users to login or register. We inferred that some users with
limited online shopping experience were trying to use their regular email
addresses and passwords to log in to the FG 2009 website.
We also found some structure design
issues. For example, we observed that some users repeatedly visited the page
“Selection Rules.” It is likely that when the users were not permitted to select
any furniture in some categories (the FG website limited each user to select
one piece of furniture under each category), they had to go to the page
“Selection Rules” to find the reasons. To reduce these redundant operations and
improve user experience, the help function for selection rules should be
redesigned to make it more convenient for users to consult.
CHAPTER 5
5.0
SYSTEM STUDY:
5.1 FEASIBILITY STUDY:
The feasibility of the
project is analyzed in this phase and business proposal is put forth with a
very general plan for the project and some cost estimates. During system
analysis the feasibility study of the proposed system is to be carried out.
This is to ensure that the proposed system is not a burden to the company. For feasibility analysis, some understanding
of the major requirements for the system is essential.
Three
key considerations involved in the feasibility analysis are
- ECONOMICAL
FEASIBILITY
- TECHNICAL
FEASIBILITY
- SOCIAL
FEASIBILITY
5.1.1 ECONOMICAL FEASIBILITY:
This study is carried out to check the economic
impact that the system will have on the organization. The amount of fund that
the company can pour into the research and development of the system is
limited. The expenditures must be justified. Thus the developed system as well
within the budget and this was achieved because most of the technologies used
are freely available. Only the customized products had to be purchased.
5.1.2 TECHNICAL FEASIBILITY
This study is carried out to check the technical feasibility,
that is, the technical requirements of the system. Any system developed must
not have a high demand on the available technical resources. This will lead to
high demands on the available technical resources. This will lead to high
demands being placed on the client. The developed system must have a modest
requirement, as only minimal or null changes are required for implementing this
system.
5.1.3 SOCIAL FEASIBILITY:
The aspect of study is to check the level of
acceptance of the system by the user. This includes the process of training the
user to use the system efficiently. The user must not feel threatened by the
system, instead must accept it as a necessity. The level of acceptance by the
users solely depends on the methods that are employed to educate the user about
the system and to make him familiar with it. His level of confidence must be
raised so that he is also able to make some constructive criticism, which is
welcomed, as he is the final user of the system.
5.2 SYSTEM TESTING:
Testing is a
process of checking whether the developed system is working according to the
original objectives and requirements. It is a set of
activities that can be planned in advance and conducted systematically. Testing
is vital to the success of the system. System testing makes a logical
assumption that if all the parts of the system are correct, the global will be
successfully achieved. In adequate testing if not testing leads to errors that
may not appear even many months.
This creates two problems, the time lag
between the cause and the appearance of the problem and the effect of the
system errors on the files and records within the system. A small system error
can conceivably explode into a much larger Problem. Effective testing early in
the purpose translates directly into long term cost savings from a reduced
number of errors. Another reason for system testing is its utility, as a
user-oriented vehicle before implementation. The best programs are worthless if
it produces the correct outputs.
5.2.1 UNIT TESTING:
|
Description
|
Expected result
|
|
Test for application window
properties.
|
All the properties of the windows are
to be properly aligned and displayed.
|
|
Test for mouse operations.
|
All the mouse operations like click,
drag, etc. must perform the necessary operations without any exceptions.
|
A program
represents the logical elements of a system. For a program to run
satisfactorily, it must compile and test data correctly and tie in properly
with other programs. Achieving an error free program is the responsibility of
the programmer. Program testing checks
for two types
of errors: syntax
and logical. Syntax error is a
program statement that violates one or more rules of the language in which it
is written. An improperly defined field dimension or omitted keywords are
common syntax errors. These errors are shown through error message generated by
the computer. For Logic errors the programmer must examine the output
carefully.
5.1.2 FUNCTIONAL TESTING:
Functional
testing of an application is used to prove the application delivers correct
results, using enough inputs to give an adequate level of confidence that will
work correctly for all sets of inputs. The functional testing will need to
prove that the application works for each client type and that personalization
function work correctly.When a program is tested, the actual output is
compared with the expected output. When there is a discrepancy the sequence of
instructions must be traced to determine the problem. The process is facilitated by breaking the
program into self-contained portions, each of which can be checked at certain
key points. The idea is to compare program values against desk-calculated
values to isolate the problems.
|
Description
|
Expected result
|
|
Test for all modules.
|
All peers should communicate in the
group.
|
|
Test for various peer in a distributed
network framework as it display all users available in the group.
|
The result after execution should give
the accurate result.
|
5.1. 3 NON-FUNCTIONAL TESTING:
The Non Functional software testing
encompasses a rich spectrum of testing strategies, describing the expected
results for every test case. It uses symbolic analysis techniques. This testing
used to check that an application will work in the operational environment.
Non-functional testing includes:
- Load
testing
- Performance
testing
- Usability
testing
- Reliability
testing
- Security
testing
5.1.4 LOAD TESTING:
An important
tool for implementing system tests is a Load generator. A Load generator is
essential for testing quality requirements such as performance and stress. A
load can be a real load, that is, the system can be put under test to real
usage by having actual telephone users connected to it. They will generate test
input data for system test.
|
Description
|
Expected result
|
|
It is necessary to ascertain that the
application behaves correctly under loads when ‘Server busy’ response is
received.
|
Should designate another active node
as a Server.
|
5.1.5 PERFORMANCE TESTING:
Performance
tests are utilized in order to determine the widely defined performance of the
software system such as execution time associated with various parts of the
code, response time and device utilization. The intent of this testing is to
identify weak points of the software system and quantify its shortcomings.
|
Description
|
Expected result
|
|
This is required to assure that an
application perforce adequately, having the capability to handle many peers,
delivering its results in expected time and using an acceptable level of
resource and it is an aspect of operational management.
|
Should handle large input values, and
produce accurate result in a expected
time.
|
5.1.6 RELIABILITY TESTING:
The software
reliability is the ability of a system or component to perform its required
functions under stated conditions for a specified period of time and it is
being ensured in this testing. Reliability can be expressed as the ability of
the software to reveal defects under testing conditions, according to the
specified requirements. It the portability that a software system will operate
without failure under given conditions for a given time interval and it focuses
on the behavior of the software element. It forms a part of the software
quality control team.
|
Description
|
Expected result
|
|
This is to check that the server is
rugged and reliable and can handle the failure of any of the components
involved in provide the application.
|
In case of failure of the server an alternate server should take
over the job.
|
5.1.7 SECURITY TESTING:
Security
testing evaluates system characteristics that relate to the availability,
integrity and confidentiality of the system data and services. Users/Clients
should be encouraged to make sure their security needs are very clearly known
at requirements time, so that the security issues can be addressed by the
designers and testers.
|
Description
|
Expected result
|
|
Checking that the user identification
is authenticated.
|
In case failure it should not be
connected in the framework.
|
|
Check whether group keys in a tree are
shared by all peers.
|
The peers should know group key in the
same group.
|
5.1.8 WHITE BOX TESTING:
White box
testing, sometimes called glass-box
testing is a test case
design method that uses
the control structure
of the procedural design to
derive test cases. Using
white box testing
method, the software engineer
can derive test
cases. The White box testing focuses on the inner structure of the
software structure to be tested.
|
Description
|
Expected result
|
|
Exercise all logical decisions on
their true and false sides.
|
All the logical decisions must be
valid.
|
|
Execute all loops at their boundaries
and within their operational bounds.
|
All the loops must be finite.
|
|
Exercise internal data structures to ensure
their validity.
|
All the data structures must be valid.
|
5.1.9 BLACK BOX TESTING:
Black box
testing, also called behavioral testing, focuses on the functional requirements
of the software. That is,
black testing enables
the software engineer to derive
sets of input
conditions that will
fully exercise all
functional requirements for a
program. Black box testing is not
alternative to white box techniques.
Rather it is
a complementary approach
that is likely
to uncover a different
class of errors
than white box methods. Black box testing attempts to find
errors which focuses on inputs, outputs, and principle function of a software
module. The starting point of the black box testing is either a specification
or code. The contents of the box are hidden and the stimulated software should
produce the desired results.
|
Description
|
Expected result
|
|
To check for incorrect or missing
functions.
|
All the functions must be valid.
|
|
To check for interface errors.
|
The entire interface must function
normally.
|
|
To check for errors in a data
structures or external data base access.
|
The database updation and retrieval
must be done.
|
|
To check for initialization and
termination errors.
|
All the functions and data structures must
be initialized properly and terminated normally.
|
All
the above system testing strategies are carried out in as the development,
documentation and institutionalization of the proposed goals and related
policies is essential.
CHAPTER
6
6.0 SOFTWARE DESCRIPTION:
6.1 JAVA
TECHNOLOGY:
Java technology is both a programming language and a
platform.
The Java Programming Language
The Java
programming language is a high-level language that can be characterized by all
of the following buzzwords:
With most
programming languages, you either compile or interpret a program so that you
can run it on your computer. The Java programming language is unusual in that a
program is both compiled and interpreted. With the compiler, first you
translate a program into an intermediate language called Java byte codes
—the platform-independent codes interpreted by the interpreter on the Java
platform. The interpreter parses and runs each Java byte code instruction on
the computer. Compilation happens just once; interpretation occurs each time
the program is executed. The following figure illustrates how this works.
You can think of Java byte codes as the machine code
instructions for the Java Virtual Machine (Java VM). Every Java
interpreter, whether it’s a development tool or a Web browser that can run
applets, is an implementation of the Java VM. Java byte codes help make “write
once, run anywhere” possible. You can compile your program into byte codes on
any platform that has a Java compiler. The byte codes can then be run on any
implementation of the Java VM. That means that as long as a computer has a Java
VM, the same program written in the Java programming language can run on
Windows 2000, a Solaris workstation, or on an iMac.
6.2 THE JAVA PLATFORM:
A platform is the hardware or software
environment in which a program runs. We’ve already mentioned some of the most
popular platforms like Windows 2000, Linux, Solaris, and MacOS. Most platforms
can be described as a combination of the operating system and hardware. The
Java platform differs from most other platforms in that it’s a software-only
platform that runs on top of other hardware-based platforms.
The Java
platform has two components:
- The Java Virtual Machine (Java
VM)
- The Java Application Programming
Interface (Java API)
You’ve already been introduced to the Java VM. It’s
the base for the Java platform and is ported onto various hardware-based
platforms.
The Java API
is a large collection of ready-made software components that provide many
useful capabilities, such as graphical user interface (GUI) widgets. The Java
API is grouped into libraries of related classes and interfaces; these
libraries are known as packages. The next section, What Can Java
Technology Do? Highlights what functionality some of the packages in the Java
API provide.
The following
figure depicts a program that’s running on the Java platform. As the figure
shows, the Java API and the virtual machine insulate the program from the
hardware.
Native code is code that after you compile it, the compiled
code runs on a specific hardware platform. As a platform-independent
environment, the Java platform can be a bit slower than native code. However,
smart compilers, well-tuned interpreters, and just-in-time byte code compilers
can bring performance close to that of native code without threatening
portability.
6.3 WHAT CAN JAVA TECHNOLOGY DO?
The most common types of programs written in the
Java programming language are applets and applications. If
you’ve surfed the Web, you’re probably already familiar with applets. An applet
is a program that adheres to certain conventions that allow it to run within a
Java-enabled browser.
However, the
Java programming language is not just for writing cute, entertaining applets
for the Web. The general-purpose, high-level Java programming language is also
a powerful software platform. Using the generous API, you can write many types
of programs.
An application
is a standalone program that runs directly on the Java platform. A special kind
of application known as a server serves and supports clients on a
network. Examples of servers are Web servers, proxy servers, mail servers, and
print servers. Another specialized program is a servlet.
A servlet can
almost be thought of as an applet that runs on the server side. Java Servlets
are a popular choice for building interactive web applications, replacing the
use of CGI scripts. Servlets are similar to applets in that they are runtime
extensions of applications. Instead of working in browsers, though, servlets
run within Java Web servers, configuring or tailoring the server.
How does the
API support all these kinds of programs? It does so with packages of software
components that provides a wide range of functionality. Every full
implementation of the Java platform gives you the following features:
- The essentials: Objects, strings,
threads, numbers, input and output, data structures, system properties, date
and time, and so on.
- Applets: The set of
conventions used by applets.
- Networking: URLs, TCP
(Transmission Control Protocol), UDP (User Data gram Protocol) sockets, and IP
(Internet Protocol) addresses.
- Internationalization: Help for
writing programs that can be localized for users worldwide. Programs can
automatically adapt to specific locales and be displayed in the appropriate
language.
- Security: Both low level and
high level, including electronic signatures, public and private key management,
access control, and certificates.
- Software components: Known as
JavaBeansTM, can plug into existing component architectures.
- Object serialization: Allows
lightweight persistence and communication via Remote Method Invocation (RMI).
- Java Database Connectivity (JDBCTM):
Provides uniform access to a wide range of relational databases.
The Java platform also has APIs for 2D and 3D
graphics, accessibility, servers, collaboration, telephony, speech, animation,
and more. The following figure depicts what is included in the Java 2 SDK.
6.4 HOW WILL JAVA TECHNOLOGY CHANGE
MY LIFE?
We can’t promise you fame, fortune, or even a job if you
learn the Java programming language. Still, it is likely to make your programs
better and requires less effort than other languages. We believe that Java
technology will help you do the following:
- Get started quickly: Although the
Java programming language is a powerful object-oriented language, it’s easy to
learn, especially for programmers already familiar with C or C++.
- Write less code: Comparisons of
program metrics (class counts, method counts, and so on) suggest that a program
written in the Java programming language can be four times smaller than the
same program in C++.
- Write better code: The Java programming
language encourages good coding practices, and its garbage collection helps you
avoid memory leaks. Its object orientation, its JavaBeans component
architecture, and its wide-ranging, easily extendible API let you reuse other
people’s tested code and introduce fewer bugs.
- Develop programs more quickly:
Your development time may be as much as twice as fast versus writing the same
program in C++. Why? You write fewer lines of code and it is a simpler
programming language than C++.
- Avoid platform dependencies with 100% Pure Java:
You can keep your program portable by avoiding the use of libraries written in
other languages. The 100% Pure JavaTM Product Certification Program
has a repository of historical process manuals, white papers, brochures, and
similar materials online.
- Write once, run anywhere:
Because 100% Pure Java programs are compiled into machine-independent byte
codes, they run consistently on any Java platform.
- Distribute software more easily:
You can upgrade applets easily from a central server. Applets take advantage of
the feature of allowing new classes to be loaded “on the fly,” without
recompiling the entire program.
6.5 ODBC:
Microsoft Open
Database Connectivity (ODBC) is a standard programming interface for
application developers and database systems providers. Before ODBC became a de
facto standard for Windows programs to interface with database systems,
programmers had to use proprietary languages for each database they wanted to
connect to. Now, ODBC has made the choice of the database system almost
irrelevant from a coding perspective, which is as it should be. Application
developers have much more important things to worry about than the syntax that
is needed to port their program from one database to another when business
needs suddenly change.
Through the
ODBC Administrator in Control Panel, you can specify the particular database
that is associated with a data source that an ODBC application program is
written to use. Think of an ODBC data source as a door with a name on it. Each
door will lead you to a particular database. For example, the data source named
Sales Figures might be a SQL Server database, whereas the Accounts Payable data
source could refer to an Access database. The physical database referred to by
a data source can reside anywhere on the LAN.
The ODBC system files are not installed on your
system by Windows 95. Rather, they are installed when you setup a separate
database application, such as SQL Server Client or Visual Basic 4.0. When the
ODBC icon is installed in Control Panel, it uses a file called ODBCINST.DLL. It
is also possible to administer your ODBC data sources through a stand-alone
program called ODBCADM.EXE. There is a 16-bit and a 32-bit version of this
program and each maintains a separate list of ODBC data sources.
From a
programming perspective, the beauty of ODBC is that the application can be
written to use the same set of function calls to interface with any data
source, regardless of the database vendor. The source code of the application
doesn’t change whether it talks to Oracle or SQL Server. We only mention these
two as an example. There are ODBC drivers available for several dozen popular
database systems. Even Excel spreadsheets and plain text files can be turned
into data sources. The operating system uses the Registry information written
by ODBC Administrator to determine which low-level ODBC drivers are needed to
talk to the data source (such as the interface to Oracle or SQL Server). The
loading of the ODBC drivers is transparent to the ODBC application program. In
a client/server environment, the ODBC API even handles many of the network
issues for the application programmer.
The advantages
of this scheme are so numerous that you are probably thinking there must be
some catch. The only disadvantage of ODBC is that it isn’t as efficient as
talking directly to the native database interface. ODBC has had many detractors
make the charge that it is too slow. Microsoft has always claimed that the
critical factor in performance is the quality of the driver software that is
used. In our humble opinion, this is true. The availability of good ODBC
drivers has improved a great deal recently. And anyway, the criticism about
performance is somewhat analogous to those who said that compilers would never
match the speed of pure assembly language. Maybe not, but the compiler (or
ODBC) gives you the opportunity to write cleaner programs, which means you
finish sooner. Meanwhile, computers get faster every year.
6.6 JDBC:
In an effort
to set an independent database standard API for Java; Sun Microsystems
developed Java Database Connectivity, or JDBC. JDBC offers a generic SQL
database access mechanism that provides a consistent interface to a variety of
RDBMSs. This consistent interface is achieved through the use of “plug-in”
database connectivity modules, or drivers. If a database vendor wishes
to have JDBC support, he or she must provide the driver for each platform that
the database and Java run on.
To gain a
wider acceptance of JDBC, Sun based JDBC’s framework on ODBC. As you discovered
earlier in this chapter, ODBC has widespread support on a variety of platforms.
Basing JDBC on ODBC will allow vendors to bring JDBC drivers to market much
faster than developing a completely new connectivity solution.
JDBC was
announced in March of 1996. It was released for a 90 day public review that
ended June 8, 1996. Because of user input, the final JDBC v1.0 specification
was released soon after.
The remainder
of this section will cover enough information about JDBC for you to know what
it is about and how to use it effectively. This is by no means a complete
overview of JDBC. That would fill an entire book.
6.7 JDBC Goals:
Few software
packages are designed without goals in mind. JDBC is one that, because of its
many goals, drove the development of the API. These goals, in conjunction with
early reviewer feedback, have finalized the JDBC class library into a solid
framework for building database applications in Java.
The goals that
were set for JDBC are important. They will give you some insight as to why
certain classes and functionalities behave the way they do. The eight design
goals for JDBC are as follows:
SQL
Level API
The designers felt that their main goal was to
define a SQL interface for Java. Although not the lowest database interface
level possible, it is at a low enough level for higher-level tools and APIs to
be created. Conversely, it is at a high enough level for application
programmers to use it confidently. Attaining this goal allows for future tool
vendors to “generate” JDBC code and to hide many of JDBC’s complexities from
the end user.
SQL Conformance
SQL syntax varies as you move from database vendor
to database vendor. In an effort to support a wide variety of vendors, JDBC
will allow any query statement to be passed through it to the underlying
database driver. This allows the connectivity module to handle non-standard
functionality in a manner that is suitable for its users.
JDBC
must be implemental on top of common database interfaces
The JDBC SQL API must “sit” on top of other common
SQL level APIs. This goal allows JDBC to use existing ODBC level drivers by the
use of a software interface. This interface would translate JDBC calls to ODBC
and vice versa.
- Provide a Java interface that is
consistent with the rest of the Java system
Because of Java’s acceptance in the user community
thus far, the designers feel that they should not stray from the current design
of the core Java system.
This goal probably appears in all software design
goal listings. JDBC is no exception. Sun felt that the design of JDBC should be
very simple, allowing for only one method of completing a task per mechanism.
Allowing duplicate functionality only serves to confuse the users of the API.
- Use strong, static typing wherever
possible
Strong typing allows for more error checking to be
done at compile time; also, less error appear at runtime.
- Keep the common cases simple
Because more often than not, the usual SQL calls
used by the programmer are simple SELECT’s,
INSERT’s,
DELETE’s
and UPDATE’s,
these queries should be simple to perform with JDBC. However, more complex SQL
statements should also be possible.
Finally we decided to precede
the implementation using Java Networking.
And for dynamically updating
the cache table we go for MS Access database.
Java ha
two things: a programming language and a platform.
Java is
a high-level programming language that is all of the following
Simple Architecture-neutral
Object-oriented Portable
Distributed
High-performance
Interpreted Multithreaded
Robust Dynamic Secure
Java is
also unusual in that each Java program is both compiled and interpreted. With a
compile you translate a Java program into an intermediate language called Java
byte codes the platform-independent code instruction is passed and run on the
computer.
Compilation
happens just once; interpretation occurs each time the program is executed. The
figure illustrates how this works.
6.7 NETWORKING TCP/IP STACK:
The TCP/IP stack is shorter than the OSI one:
TCP is a connection-oriented protocol; UDP (User
Datagram Protocol) is a connectionless protocol.
IP datagram’s:
The IP layer provides a connectionless and unreliable
delivery system. It considers each datagram independently of the others. Any
association between datagram must be supplied by the higher layers. The IP
layer supplies a checksum that includes its own header. The header includes the
source and destination addresses. The IP layer handles routing through an
Internet. It is also responsible for breaking up large datagram into smaller
ones for transmission and reassembling them at the other end.
UDP:
UDP is also connectionless and unreliable. What it
adds to IP is a checksum for the contents of the datagram and port numbers.
These are used to give a client/server model – see later.
TCP:
TCP supplies logic to give a reliable
connection-oriented protocol above IP. It provides a virtual circuit that two
processes can use to communicate.
Internet addresses
In order to use a service, you must be able to find
it. The Internet uses an address scheme for machines so that they can be
located. The address is a 32 bit integer which gives the IP address.
Network address:
Class A uses 8 bits for the network address with 24
bits left over for other addressing. Class B uses 16 bit network addressing.
Class C uses 24 bit network addressing and class D uses all 32.
Subnet address:
Internally, the UNIX network is divided into sub
networks. Building 11 is currently on one sub network and uses 10-bit
addressing, allowing 1024 different hosts.
Host address:
8 bits are finally used for host addresses within our
subnet. This places a limit of 256 machines that can be on the subnet.
Total address:
The 32 bit address is usually written as 4 integers
separated by dots.
Port addresses
A service exists on a host, and is identified by its
port. This is a 16 bit number. To send a message to a server, you send it to
the port for that service of the host that it is running on. This is not
location transparency! Certain of these ports are “well known”.
Sockets:
A socket is a data structure maintained by the system
to handle network connections. A socket is created using the call socket. It returns an integer that is like a file descriptor.
In fact, under Windows, this handle can be used with Read File and Write File
functions.
#include <sys/types.h>
#include <sys/socket.h>
int socket(int family, int type, int protocol);
Here “family” will be AF_INET for IP communications, protocol will be zero, and type will depend on whether TCP or UDP is used. Two
processes wishing to communicate over a network create a socket each. These are
similar to two ends of a pipe – but the actual pipe does not yet exist.
6.8 JFREE
CHART:
JFreeChart is a free 100% Java chart library that
makes it easy for developers to display professional quality charts in their
applications. JFreeChart’s extensive feature set includes:
A consistent and well-documented API, supporting a
wide range of chart types;
A flexible design that is easy to extend, and
targets both server-side and client-side applications;
Support for many output types, including Swing
components, image files (including PNG and JPEG), and vector graphics file
formats (including PDF, EPS and SVG);
JFreeChart is “open source” or, more
specifically, free software. It is distributed
under the terms of the GNU Lesser General Public Licence
(LGPL), which permits use in proprietary applications.
6.8.1. Map Visualizations:
Charts showing values that relate to geographical
areas. Some examples include: (a) population density in each state of the
United States, (b) income per capita for each country in Europe, (c) life
expectancy in each country of the world. The tasks in this project include:
Sourcing freely redistributable vector outlines for the countries of the world,
states/provinces in particular countries (USA in particular, but also other
areas);
Creating an appropriate dataset interface (plus
default implementation), a rendered, and integrating this with the existing
XYPlot class in JFreeChart; Testing, documenting, testing some more,
documenting some more.
6.8.2. Time Series Chart Interactivity
Implement a new (to JFreeChart) feature for
interactive time series charts — to display a separate control that shows a
small version of ALL the time series data, with a sliding “view”
rectangle that allows you to select the subset of the time series data to
display in the main chart.
6.8.3. Dashboards
There is currently a lot of interest in dashboard
displays. Create a flexible dashboard mechanism that supports a subset of
JFreeChart chart types (dials, pies, thermometers, bars, and lines/time series)
that can be delivered easily via both Java Web Start and an applet.
6.8.4. Property Editors
The property editor mechanism in JFreeChart only
handles a small subset of the properties that can be set for charts. Extend (or
reimplement) this mechanism to provide greater end-user control over the
appearance of the charts.
CHAPTER 8
8.1
CONCLUSION:
We have developed a new method for the
identification and improvement of navigation-related Web usability problems by checking
extracted usage patterns against cognitive user models. As demonstrated by our
case study, our method can identify areas with usability issues to help improve
the usability of Web systems. Once a website is operational, our method can be
continuously applied and drive ongoing refinements. In contrast with
traditional software products and systems, Web based applications have
shortened development cycles and prolonged maintenance cycles. Our method can
contribute significantly to continuous usability improvement over these prolonged
maintenance cycles. The usability improvement in successive iterations can be
quantified by the progressively better effectiveness (higher task completion
rate) and efficiency (less time for given tasks).
Our method is not intended to and cannot
replace heuristic usability evaluation by experts and user-centered usability
testing. It complements these traditional usability practices and can be
incorporated into an integrated strategy for Web usability assurance. With
automated tool support for a significant part of the activities involved, our
method is cost-effective. It would be particularly valuable in the two common
situations, where an adequate number of actual users cannot be involved in
testing and cognitive experts are in short supply. Server logs in our method
represent real users’ operations in natural working conditions, and our IUIP
models injected with human behavior cognition represent part of cognitive
experts’ work. We are currently integrating these modeling and analysis tools into
a tool suite that supports measurement, analysis, and overall quality improvement
for Web applications.
8.2 FUTURE ENHANCEMENT:
In
the future, we should and must carry out validation studies with large-scale Web
applications. We also plan to explore additional approaches to discover Web
usage patterns and related usability problems generalizable to other
interesting domains. For example, we have already started exploring deviation
calculation and analysis at the trail level instead of at the individual page level.
Such analyses might be more meaningful and yield more interesting results for
Web applications with complex structure and operation sequences. Our IUIP
modeling architecture and supporting tools also need to be further enhanced and
optimized for more complex tasks. We will also further expand our usability research
to cover more usability aspects to improve Web users’ overall satisfaction.