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Research Journal
of
Aleppo University
Engineering Science Series
A Periodical Issued by University of Aleppo
Vol. 78 - 2010
Published at: April /2014
ISSN 2227-7501
All rights reserved .No part of this publication may be
reproduced ,stored in a retrieval system or transmitted in any
form without the prior written permission of the publisher .
Engineering Science Series
Chairman of the Editorial Prof. Dr. Najah Tannous
Vice president for scientific research and high studies affairs
Editor in Chief Prof. Dr. Mohamad Khaldoun Dermoch
Editorial Board
Prof. Elias Toshan Prof. Azam Katkhuda Prof. Imad Antibas
Prof. Salwa Sakal Prof. Abd Hakim Bannoud Dr. Sohel Khwatmy
PRODUCTION Eng.Rama Mulki
The view expressed in this issue are those of the authors and do not necessarily
reflect the views of the Editorial Board or the Policies of the University of Aleppo
5
Contents
Dr. Ikbal Arab Applying Analytical Usability
Evaluation Methods on Two eLearning
Environments via a Local Area
Network
7
Dr. Riad Al-Mostafa
Dr. A. Kussay Kayyali
Abir Ali Al-Jarbouh
Studying the Effects of Angle
Variances of Lighting Lamp on
Illumination Flow Distribution
25
Dr. Ahmad Al Sayed
Mohammed Al Bakkar
Influence of the Pocket Form on
Stability of Hybrid Journal Bearing
27
Dr. Abd Kader Joukhadar
Dr. A. Ammar Naassani
M. Samir Nawlo
Adaptive Backstepping-Assisted
MRAS for Speed Control of DC Motor
Drives
29
Dr. Ikbal Arab
Dr. Mazen Saaid
Rym Khawam
Comparative Study of Tombstones
Transformation Functions
31
Dr. M. Jameel Alshehne
Dr. Ahmad Almansour
Abdulhadi Ammory
Numerical Study on the Effect of RSW
Process Parameters on Characteristics
of Weld-Bonded joints Using FEM
33
Dr. Abou Hajar
Dr. B. Barmada
R. Teirouz
New Method to Enhance the
Performance of Mobile AD HOC
Networks
35
Dr. Nabhan Khayata The Thermodynamic Study of
Adsorption Refrigeration System and
Effect of Operating and Design
Parameters on its Performance
37
Dr. Imad Antibas Determining the Optimum Parameters
for the Grinding Process of Fish Feed
39
Dr. Nidal Duya
Dr. Nizar Ajib
Abdul Mannan Habib
Enhancement of Release System Using
Visual Optical Imaging
41
Dr. M. Dubsi
Dr. A. G. Shehabi
M.Tair
Three Dimensional Animation of
Industrial Robot Kinematics
43
Dr. M. Jalal Tarmanini
Dr. Mohamad Dakak
Faisal Alalloush
Designing and Simulating the
Performance of a Hybrid Renewable
Energy System by Using Photovoltaic
and Fuel Cells
45
Dr. Khalaf AL Abdullah
Dr.Oroba Faraj AL Ali
Mesoun Shaheed
Designing and Simulating Rf Filters
Using the Scattering Parameters
(S-Parameters)
47
6
Dr. Yahya Najjar Integrated System Using Advanced
Speech Processing Technologies
49
Dr. Abdul Qader Melhem
Mike Saad
Studying the Effect of Intermediate
Diaphragms on the Elastic and Elastic
–Plastic Behavior of Simple Span
Prestressed Concrete Highway Bridges
51
Dr. Nidal Shehadeh
Dr. Maher Ghazal
Malla Dej
Analytical Study for the Situation of
Post Graduate Studies at Civil
Engineering College from Viewpoints
of Its Staff
53
Dr. Sami Altrsha
Dr. Nasr Alkasem
Ahmed Al-Tahir
Study of Electrical Faults in Electricity
Network of Tension 66 KV in the
Province of Hasaka, Their Causes, and
the Performance of Protection Devices
Applied to Them
55
Dr. Kinda Abou Kaseem Retrieval Information from E-
Learning System 57
Dr. Onabi Ammar Computing the Maximum Value of
Twisting Factor Accompanying
Torsion in Plate
59
Dr. Abdul Alim Dib The Structural Health Monitoring of
Structures (Plates) by Means of
Measuring Their Vibrations
61
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
7
Applying Analytical Usability Evaluation Methods on
Two eLearning Environments via a Local Area Network
Ikbal Arab
Dept. of Computer Engineering, Faculty of Electrical & Electronic Engineering,
University of Aleppo
Abstract
Usability engineering is the process of evaluating how usable a
product is in order to improve the usability of the product and enhance
the process by which products will be designed and developed in the
future. Usability inspection is an important approach to achieving
usability. Human inspectors are requested to detect usability problems
during the user interface design because solving them will help
improve user interface design and its usability. It usually requires
multiple inspectors, who either work individually or in a team. We
practiced different usability inspection techniques (analytical testing
methods), including heuristic evaluation and cognitive walkthrough.
We investigated the relative effectiveness of analytical usability
evaluation methods in identifying usability problems in two learning
management systems (or two e-learning environments): Student
Central and Moodle. The results were replicated across the two
systems and showed that the analytical testing condition identified a
number of issues, and identified some relatively severe issues that were
relatively significant by the user testing conditions.
1. Introduction An important issue in software engineering life cycle is where
to use it. Usability engineering is the process of evaluating how usable
a product is in order to improve the usability of the product and
enhance the process by which products will be designed and developed
in the future [1]. We can distinguish two types of evaluation methods:
empirical evaluation (or user-based testing) and analytical evaluation
(or usability inspection).
Received 3/12/2009
Accepted 23/2/2010
Dr. Ikbal Arab
8
Empirical evaluation means that information is derived from
actual users of the system or people who resemble users. Analytical
evaluation means that the information comes from other sources, in
particular, expert opinion. In this paper, we are interested in defining
the scope of expert testing and developing a testing plan to apply two
inspection methods: CW and HE onto two learning management
systems or environments: Student Central and Moodle, under
consideration.
This paper is organized as follows: section 2 presents two e-
learning environments used in the case studies with the importance
accorded to each one; section 3 presents the methodology used for the
existing usability inspection methods; section 4 describes how the case
studies and the framework that guided the usability evaluations were
planned; in section 5, we illustrate how the data were analyzed and the
results are shown; in section 6 results are discussed; and in section 7
some conclusions are exposed.
2. Theoretical Background E-learning is the delivery of teaching material electronically
with the added value of maintaining standards and quality across the
board without the limitation of a specific location. It involves the use
of multimedia (text graphics, animation, audio, video and video
conferencing) and is interactive. In an interactive learning
environment, a person can navigate through it, select relevant
information, respond to questions using input devices (keyboard,
mouse, touch screen, or voice command system), complete tasks,
communicate with others, and receive assessment feedback [2]. A
major challenge for designers and Human-Computer Interaction (HCI)
researchers is to develop software tools to engage learners and support
their learning even at a distance. As for any interactive system, the
quality of the user interface is a primary requirement. If the e-learning
system interface is not usable, the student could spend more time
learning how to use it rather than learning the educational content.
Thus, in this particular context, issues of usability will assume greater
significance [3].
Many LMS (Learning Management Systems) environments
exist. Some of them are commercial, such as Blackboard (Student
Central) [4] and others are open source, such as Moodle [5]. In this
paper we will study Student Central and Moodle from usability
EXPERTS‟ testing point of view. This means that we will be interested
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
9
in EXPERT usability evaluation using inspection methods: HE
(Heuristic Evaluation) and CW (Cognitive Walkthrough).
3. eMthodology Effective e-learning systems interface should hide its
complexity to learners, providing an easy interaction to grasp the
students‟ interest. A poorly designed interface becomes a barrier to
effective learning [6]. So, ensuring usability is one of the main
challenges of e-learning systems developers [7]. As an
interface/system designer, we will also need to evaluate the
interface/system design when no users are present. Users' time is
almost never a free or unlimited resource. Most users have their own
work to do, and they are able to devote only limited time to this
activity. When users do take time to look at the interface/design, it
should be as free of problems as possible. A second reason for
evaluating a design without users is that a good evaluation can catch
problems that an evaluation with only a few users may not reveal. So,
analytical evaluation (or usability inspection) is one of the Usability
Evaluation Methods (UEMs) that can be made by experts. There are
two main approaches to evaluate an interface/system in the absence of
users [9]: Cognitive Walkthrough (CW) and Heuristic Evaluation
(HE). In usability inspection, problems are found through the expertise
of the inspectors and the inspection techniques they use.
3.1. Cognitive Walkthrough-CW
This approach requires a detailed review of a sequence of
actions. The sequence of actions refers to the steps that an interface
will require a user to perform in order to accomplish some task. The
evaluators then walk through that action sequence to check it for
potential usability problems [10]. Usually, the main focus of the
cognitive walkthrough is to establish how easy a system is to learn.
More specifically, the focus is on learning through exploration. To do
this, the evaluators go through each step in the task and provide a story
about why that step is or is not good for a new user.
3.2. Heuristic Evaluation-HE
Heuristic Evaluation involves having a set of evaluators to
examine the user interface and judge its compliance with recognized
usability principles (the "heuristics"). Each individual evaluator
inspects the system alone, using or not using task scenarios. Its e-
activeness depends on the expertise of the inspectors and the variety of
their inspections [9]. In this paper we are interested in usability experts
Dr. Ikbal Arab
10
testing of Student Central and Moodle e-learning environments. These
testing sessions are accomplished in the offices. We made a test plan
for each environment under consideration with an appropriate usability
inspection method.
4. Usability Inspection Tests Plan In this section we will present the accomplishment of our tests
plans for studied Student Central and Moodle environments using CW
and HE methods. The purpose of the usability inspection evaluation of
the Student Central and Moodle LMS environments is to evaluate the
potential of errors and difficulties involved in using them by experts
helping in teaching and learning activities. Five expert analysts
contributed to CW and HE evaluation studies. Three of these
participants are research fellows in Brighton University‟s School of
Computing, Mathematical and Information Sciences. One of
participants is a researcher at Aleppo University. The last one is a
distant learning trainer working at CNF (Campus Numerique
Francophone) located at Aleppo University Campus.
4.1. Cognitive Walkthrough Test Plan
To do a cognitive walkthrough we need four things [10]:
A description of the (or prototype of the) system. So, it does not
have to be complete, but it should be fairly detailed.
A description of the tasks to perform on the system by the user.
They should be representative tasks that most users will want to do.
A complete, written list of the actions needed to complete these
tasks on the given system (or prototype of given system).
An indication of who the users are and what kind of experience and
knowledge the evaluators can assume about them.
CW consists of two phases: preparation and execution. In the
preparation phase the analyst selects tasks to be analyzed and specifies
the knowledge, experience, and skills a user can be expected to bring
to the task. For each task the analyst specifies the correct action and
the expected feedback of the system. In the execution phase the analyst
closely examines each action in an action sequence and asks the four
questions cited below:
A. Will the users be trying to produce whatever effect the action has?
Are the assumptions about what task the action is supporting
correct given the user's experience and knowledge up to this point
in the interaction?
B. Will users be able to notice that the correct action is available?
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
11
C. Once users find the correct action at the interface, will they know
that it is the right one for the effect they are trying to produce?
D. After the action is taken, will users understand the feedback they
get?
For each question about a given action, the expert should either
identify a success or a failure story. So, answers should be Yes or No
with additional comments to explain (particularly in the case of No
answers). During the execution phase, the expert should record any
additional assumptions about user knowledge requirements, e.g.
information about what the user must know prior to performing the
task and what the user should learn while performing the task. Side
issues (detection of spelling errors in menus) as well as design changes
are also recorded in the execution phase. An individual expert or a
group of them can perform the CW evaluation. However, since
cognitive walkthroughs are time consuming, they cannot be applied in
an exhaustive fashion. In order to cover more ground, a
complementary approach has been used, the Heuristic Evaluation
method.
4.2. Heuristic Evaluation Test Plan
Completing an HE involves working through a checklist of ten
questions and assessing the system against those questions. Optionally,
severity ratings can be assigned to the problems identified. Nielsen
advocates that 3-5 evaluators should be involved to achieve an
appropriate cost-benefit trade-off in finding problems, reflecting the
low inter-rater reliability of HE. In this study, HE was applied by
evaluators to generate usability issues. Also, no severity ratings were
proposed, since the study was focusing on what issues each approach
identified rather than the craft skill of assigning severity ratings.
In heuristic evaluation of the user interface, the following
guidelines are considered:
1. Visibility of system status - The system should always keep users
informed about what is going on, through appropriate feedback
within reasonable time.
2. Match between system and the real world - The system should
speak the user‟s language, with words, phrases and concepts
familiar to the user, rather than system-oriented terms.
3. User‟s control and freedom - Users often choose system functions
by mistakes and will need a clearly marked emergency exit to
leave the unwanted state without having to go through an extended
dialog.
Dr. Ikbal Arab
12
4. Consistency and standards - Users should not have to wonder
whether different words, situations, or actions mean the same
thing followed by platform conventions.
5. Error prevention - Even better than good error messages is a
careful design which prevents a problem from occurring in the
first place.
6. Recognition rather than recall - Make objects, actions, and options
visible. The user should not have to remember information from
one part of the dialog to another.
7. Flexibility and efficiency of use - Allow users to tailor frequent
actions.
8. Aesthetic and minimalist design - Dialogs should not contain
information which is irrelevant or rarely needed.
9. Help users recognize, diagnose and recover from errors - Error
messages should be expressed in plain language (no codes).
10. Help and documentation - Even though it is better if the system
can be used without documentation, it may be necessary to
provide help and documentation.
HE evaluation works like this:
A group of reviewers is given a small set of guidelines for usable
interface/system.
Each reviewer goes through the interface/ system two or three
times and writes down anything that he or she thinks violates any
of the guidelines.
All reviewers look at the combined list of all violations and provide
severity ratings.
An average of the severity ratings is taken to determine the
priorities for fixing the detected issues.
The reviewers meet as a group and develop a list of recommended
fixes for the highest priority problems.
5. Usability Inspection Data In this section we will show the data collected from various
sources.
5.1. Participants
All usability experts participated in briefing sessions. Three
experts are between 30 and 40 years old while two others are between
40 and 45. All experts frequently use the internet and they used these
environments. They evaluate LMS environments under consideration
that they are installed on two servers. Three experts connected to
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
13
appropriate servers via their client machines to evaluate our studied
environments. These machines are with RM Intel Core 2 CPU @
2.13GHz, 2GB RAM, screen resolution 1280*1024 under operating
system Windows XP Pro 2002 SP 2 at an internet connection rate of
100 MBps at the University of Brighton. Student Central environment
has a URL: https://studentcentral.brighton.ac.uk/webapps/login/,
whereas Moodle environment has the URL:
http://193.62.173.210/moodel/ with 1.9.2+ version. The recommended
web browser is Mozilla Firefox 2 (http://www.mozilla.org). The two
other experts evaluate Moodle LMS environment connected to Moodle
server via client machines located at CNF. Moodle is installed on a
server having linux operating system. The access to Moodle server is
made from clients‟ machines (linux OS) via an internet connection
with 8 MBps. Moodle environment has the URL:
http://192.168.1.2/moodel/ with 1.9.2+ version. The main tasks to be
evaluated by each expert are shown in Table1: Table1. Main tasks to be evaluated by experts
Task no Task description
Task1
Create a course with weekly format and setup its settings, fill in
contents of these weeks: word documents, ppt documents, images,
hyperlinks…etc.
Task2
Provide information on the teacher profile; make in each week an
assignment to inform the group of teachers (2 teachers) and the group
of students (3 students). You must alert, by e-mail, students group
and instructors group that your course slides are available.
Task3
Create tests (quiz, essay, …) and check if all students visit the course
to follow up by direct emails any students who have not yet entered
the Study Area
5.2. Cognitive Walkthrough
The main defined tasks are organized as a sequence of actions.
Evaluators will then use these actions to make assessments about the
learnability and usability of the tools. The feedback from this phase
can then be used to enhance and adapt tools before the final summative
evaluation. The success of the cognitive walkthrough evaluation
depends directly on the quality of the actions provided. The Cognitive
Walkthroughs define the seriousness of errors and also where the
errors occur in the process. Three experts evaluate walkthrough
Student Central and Moodle environments on CMIS site. Two other
experts evaluate Moodle on CNF site (machines with ADSL connected
to Internet). Each evaluator obtains 2 documents:
Dr. Ikbal Arab
14
A Cognitive Walkthrough Front Sheet as a task template sheet,
including determined walkthrough author, his or her profile, URL
of the server hosting studied environment, recommended web
browser and the scenarios composed of actions which the experts
can follow. We present in the following table (Table2) the
appropriate front sheet including Task3 list of actions.
Cognitive Walkthrough Report Resources reference the precedent
document. This document starts with evaluator‟s name, tasks to
test, technical specification of the hosted machine, scope of this
walkthrough, and user‟s profile. Finally, we present in the
following table (Table3) the appropriate report resource that keeps
track of Task3 list of actions. Table2. Front Sheet (SC LMS) of 1 expert including set of actions of Task2. Task 3 : Create tests (quiz, essay, …) and check if all students visit the course
to follow up by direct emails any students who have not yet entered
the Study Area.
Step Description Goal
1 In the Control Panel, under Content Area click on Module
material. A list with folders for weeks is shown.
Create
a test at
the end
of each
week.
2 In the toolbar, click on the Add test button. The Test
Manager screen is shown.
3 Click on Create button to create a new test. The Test
Information screen is shown.
4 Fill in the required fields to name and describe the test.
5 Click on Submit button to save the test and bring up a
Test Canvas screen.
6 In the Test Canvas screen select a question type from the
Add drop-down list (eg. Essay) and then click on Go to
add the question.
7 The Add/Modify Essay Question screen shows up. Fill in
the required fields (e.g. Question, Points), optionally
adjust other settings (e.g. category, keywords).
8 Click Sumbit button to save Question settings and return
to Test Canvas page. Optionally add/modify other
questions.
9 Click on OK button to save the Test and return to the Test
Manager screen.
Repeat steps 1-10 to create a second test for week2.
10 Click on OK button to return to the Control Panel.
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
15
11 In the Control Panel, under Content Area click on Module
material. A list with folders for weeks is shown.
12 Click on week1 to show resources for week1.
13 In the toolbar, click on the Add test button. The Add Test
screen is shown.
14 From the list of available tests, select the test for week1
and click Submit button.
15 A confirmation screen is shown, Click on OK button.
16 A Modify Test screen is shown, Click OK button.
17 The screen with resources for week1 is shown, with the
new test added. Click on OK button to return to the
Module Material screen.
Repeat steps 12-17 for week2.
18 Click on OK button to return to the Control Panel
19 In the Control Panel, under Assessment click on Course
Statistics button to show the screen Course Statistics.
Check
if
student
s visit
course?
20 From the Select Report pull down list, choose Access by
Groups. You can use Filters Options for times and users.
21 Click on Submit button to show Course Access Statistics.
Optionally change filter options or print data.
22 Click on Ok button to return to the Control Panel.
Table3. Report resource worksheet (SC LMS) of 1 expert of the Task2
# Step Comments/issues A* B* C* D*
1
b) not easy to find the option (too many
possibilities), and c) would expect adding a test
under “Assessment” instead of “Course material”
x x
16 a) why would I want to modify the test here? Would
modifications only apply to this instance of the test? x
18
b) not easy to find the option (too many
possibilities), and c) why is that under
“Assessment”? Am I right here?
x x
19
c) why would I select “Access by Groups”? I am
interested in users! d) I don‟t understand the results
page. What does it tell me?
x x
A*. Will the users be trying to produce whatever effect the action has?
B*. Will users be able to notice that the correct action is available?
C*. Once users find the correct action at the interface, will they know that it is the
right one for the effect they are trying to produce?
D*. After the action is taken, will users understand the feedback they get?
Dr. Ikbal Arab
16
The results for the two tools were tested so far in the Cognitive
Walkthrough (CW) evaluation process, Student Central and Moodle.
109 usability issues were found in total amongst the two tools. A basic
priority scale based on three levels (Table4) defines how serious the
issue is. Table4. Severity rating
Level Meaning
Low Task completed with minor complications and/or annoyance.
Medium Task completed with significant effort and failed attempts.
High Task cannot be completed.
42 usability issues were found in Student Central LMS. 41 of
the found usability issues were considered to be priority “Low”. The
single usability issue categorized as priority “Medium” is related to an
“OK” button present in the case of many actions completion. The
remaining 41 usability errors could be categorized in a variety of ways.
For the purposes of these results it may be most useful to discriminate
them in terms of the stage at which the usability issue occurs. Within
the evaluation phase, issues are defined as being at various stages A-D
(Table5). Figure1 presents the pie chart of when usability issues occur
in Student Central LMS. Table5. Stage at which usability issue occurs, S.C LMS by 3 experts
Stage at which usability issue occurs Errors
A. Will the users be trying to produce whatever effect the action has? 1
B. Will users be able to notice that the correct action is available? 17
C. Once users find the correct action at the interface, will they know
that it is the right one for the effect they are trying to produce?
19
D. After the action is taken, will users understand the feedback they
get?
3
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
17
Figure 1. Graph of when usability issues occurred, S.C LMS by 3 experts.
66 of the found usability issues (Moodle evaluation) were
considered to be priority “Low”. Two usability issues categorized as
priority “Medium” were related to assign roles page when we create a
new course and submit this command; the other is the absence of
confirmation button present in the case of many actions completion,
like the creation of teachers or students groups, and uploading files to
fill in folders that contain course contents. The results of Moodle
environment tested by Cognitive Walkthrough evaluation process are
presented in Table6 and Figure2. So, we can compare the results of
evaluation process of our tested environments obtained after applying
Cognitive Walkthrough( Figure 3). Table6. Stage at which usability issue occurs (Moodle LMS by three experts)
Stage at which usability issue occurs Errors
A. Will the users be trying to produce whatever effect the action has? 4
B. Will users be able to notice that the correct action is available? 27
C. Once users find the correct action at the interface, will they know that
it is the right one for the effect they are trying to produce?
30
D. After the action is taken, will users understand the feedback they get? 5
Figure 2. Graph of when usability issues occurred, Moodle LMS by 3 experts
Dr. Ikbal Arab
18
Figure 3. Graph of when usability issues occurred, Moodle Vs SC LMSs
5.3. Heuristic Evaluation
Heuristic evaluation is the cheapest, most rapid, and effective
way for identifying usability problems and it involves an expert
evaluating the interface against a set of recognized usability principles
(the "heuristics" [9]). Heuristic evaluation was first formally described
in presentations in the Human–Computer Interaction conference
through papers published in [8]. Since then, they have revised the set
of 10 heuristics with maximum explanatory power. Each team member
independently performed tasks for multiple times, recorded usability
issues and which heuristic violations occurred, then rated each issue in
terms of severity. Experts later discussed their independent findings,
then consolidated and prioritized usability issues according to severity
level. We used severity rating scale based on five levels (Table7). This
evaluation identified 134 usability issues in total for Student Central
and Moodle environments. For each finding (issue), there is a table
listing the specific issue, the heuristic(s) violated, and the severity of
the issue. The first number in the table refers to the number of the issue
as it appears in the complete heuristic evaluation list to test. Table 8
represents the most severe usability issues outlined in Moodle
environment. Table7. Severity rating
# Meaning
0 Don‟t agree that this is a usability problem.
1 Cosmetic, will not affect the usability of the system, fix if possible.
2 Minor, users can easily work around the problem, fixing this should be given low
priority.
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
19
3 Medium, users stumble over the problem, but quickly adapt to it, fixing this should
be given medium priority.
4 Major, users have difficulty, but are able to find workarounds, fixing this should be
mandatory before the system is launched.
5 Catastrophic, users are unable to do their work, fixing this is mandatory.
Table8. Issues found using Heuristic Evaluation Method (Moodle Environment) # Issue Heuristic
violated
Severity
rating
Task 1
4 it is unclear where we can request „create new
course‟
#1 1
5 when clicking on Courses, Add/edit courses
appears. By clicking on Add/Edit courses, new
window entitled Course Categories is displayed.
So, there is no direct access to create new course.
#1, #6 2
7 in the group bloc, when we click on „?‟ Group
mode, we exit Moodle „crash‟
#1, #10,
#5
4
8 in the availability bloc, when we click on „?‟
Enrolment key, we exit Moodle „crash‟
#1, #10,
#5
4
9 after creating course, we will obtain „Assign
Roles‟. Why? We must click on course name at
bottom to go to course
#1, #2 2
10 we must click on „turn editing on‟ #1,# 2 2
11 we do not know where we can insert a course
banner.
#1,# 7 2
12 we do not know how we can insert an image. #1,# 7 2
13-
15
it is not easy to upload a file and put its url with
alternative description.
#1, #10, 3
18 it is not easy to know how we can use „upload file‟
when we click on Files in „Administration‟ bloc.
#1, #2 2
20
21
it is not so easy to know how we can move into a
created folder of all selected documents to upload.
#1, #2,
#8
3
22
23
why we have to go to course page in week1 space
to select from pull down menu „Display a
directory‟.
#1, #2,
#8
2
Task2
3-4 it is unclear what is „Update Profile‟ specially at
the first time.
#1, #2,
#3
2
5 we must click on „turn editing on‟ #1, #2 2
6-9 it is unclear how to add an assignment from „Add
an Activity‟ pull down menu and select under
Assignments „Advanced uploading of files‟. A
window entitled „Advanced uploading of files‟
appears. When we click on „?‟ under Maximum
number of uploaded files, a window with the same
title appears, by clicking on close, a crash
produces.
#1, #2,
#8, #10
4
Dr. Ikbal Arab
20
11 it is not easy to know where we can put the
assignment it in the course page.
#1 1
12-
13
the forum display page is not clear, I do not know
what the difference is between forum types.
#8, #10 2
15-
16
too many buttons for groups management and
choosing add/remove users to compose group of 2
teachers.
#1, #3,
#10
3
17-
18
too many buttons for groups management and
choosing add/remove users to compose group of 2
teachers.
#1, #3,
#10
3
20 it is not easy to know where users can be selected
to send them a message.
#1, #2 2
21 it is not easy to know that we have to click on
„with selected users‟ to choose „Add/send
message‟.
#1 1
22 we do not know why the send button does not
appear directly (it is shown after clicking on
Preview button obligatory).
#1, #4 2
23 error occurs when we send messages. „Could not
instantiate mail function‟ and the e-mail is not sent.
#1, #9,
#3
2, 4
26 we do not know what the difference is between
forum types.
#1, #8 2
Task 3
1 it is unclear that we have to go to Questions under
Administration bloc or add as an activity menu.
#1 1
2-9 it is unclear how quizzes will be filled. Many fields
concerning feedback and others in many types of
questions.
#1, #8,
#10
3
10-
12
we do not know how to add questions into a quiz. #1, #8 2
13-
15
it is unclear how „Report‟ under Administration
will give statistics depending on participants
(teachers or students), activities and logs.
#1 1
16-
20
error occurs when we send messages. „Could not
instantiate mail function‟ and the e-mail is not sent.
#1, #9,
#3
2, 4
Table 9 shows severity ratings of Tasks1, Task2 and Task3
issues found by HE of Moodle environment. Figure4 shows severity
scale of issues found by HE of Moodle environment. Overall, Moodle
suffered primarily from minor usability problems. Only 3 problems of
severity level 4 were detected out of a total of 65 problems found. Table9. Severity ratings of all tasks (Moodle environment).
Tasks Severity
rating 1
Severity
rating 2
Severity
rating 3
Severity
rating 4
Severity
rating 5
Task 1 1 15 5 6 0
Task 2 2 16 6 7 0
Task 3 2 5 3 3 0
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
21
Concerning Student Central environment, table10 shows
severity ratings of Tasks1, Task2 and Task3 issues found by HE of
Student Central environment. Figure 5 presents severity scale of
Task1, Task2 and Task3 together (69 issues).
Figure 4. Severity scale of all tasks (Moodle environment)
Table10. Severity ratings of all tasks (Student Central environment)
Tasks Severity
rating 1
Severity
rating 2
Severity
rating 3
Severity
rating 4
Severity
rating 5
Task 1 8 17 5 0 0
Task 2 6 14 7 0 0
Task 3 2 5 5 0 0
Figure 5. Severity scale of all tasks (Student Central environment)
6. Results and Discussion By applying CW on Student Central LMS (Figure1), there is a
clear bias (46% of all errors) related to issues with users being able to
understand that an available feature on the interface will carry out the
action they desire. An example of such errors is that: to edit course
Dr. Ikbal Arab
22
design, the user would associate “course design” with content and
structure, not with style elements like menu style and banner. The
second largest area of errors (42%) refers to issues with users which
are unable to notice that a given action is available. An example of
such errors is that: by adding users by roles, it is not easy to find the
option (too many possibilities), 7% of errors are related to issues with
users not receiving sufficient feedback to let them know that an action
has been performed. An example of such errors is that: by creating a
discussion topic for each week, nothing happens after selecting this
from the Pull down list; it is not obvious that after selection we
additionally need to click the “Go” button. Only 5% of errors are
related to whether users would want to carry out the desired action.
By applying CW on Moodle LMS (Figure2), there is a clear
bias (45% of all errors) related to issues with the users being able to
understand that an available feature on the interface will carry out the
action they desire. An example of such errors is that: by editing course
setting, there are many options available such as potential candidates,
too. The second largest area of errors (41%) refers to issues with users
unable to notice that a given action is available. An example of such
errors is that: by creating a forum for a week, there are many fields to
define it that they are unclear. 8% of errors are related to issues with
users not receiving sufficient feedback to let them know that an action
has been performed. An example of such errors is that: by sending a
message to groups, the user must click on Preview button. The user
does not know what will occur. Only 6% of errors are related to
whether users would want to carry out the desired action.
Figure 6 presents clearly severity scale of all tasks obtained by
applying HE on Moodle and Student Central LMSs.
Figure6. Severity scale of all tasks (Moodle and Student Central environments)
Res. J. of Aleppo Univ. Engineering Sciences Series No. 78 2010
23
7. Conclusion Various evaluation methodologies and techniques can be
considered and applied for evaluating e-learning systems. The paper
has discussed issues related to analytical evaluation (usability
inspection methods) of two LMS environments: Student Central and
Moodle. So, reliable evaluation can be achieved by systematically
combining inspection with user-based evaluation [11]. During the
inspection, the evaluator uses LMS to perform a rigorous and
systematic analysis and produces a report in which the discovered
problems are described. In user-based methods usability problems are
found through the observation and interaction with users while they
use an interface. In fact, inspection methods have been tested to prove
that they can produce similar results to end user testing before they are
considered valid.
Although a CW evaluation can be completed on a running
system, it is especially advocated as being cost-efficient when applied
to a description of a system, e.g., user-interface specification or
storyboards. Whereas heuristic evaluation does not allow a way to
assess the quality of redesigns; the best results can often be found by
alternating both heuristic evaluation and user testing.
So, a good evaluation can catch problems that an evaluation
with only a few users may not be revealed. Every user will have a
slightly different set of problems, and the testing will not uncover
problems that the few users tested do not have. Also, it will not
uncover problems that users might have after they get more
experience. An evaluation without users will not uncover all the
problems either. But doing both kinds of evaluation significantly
improves the chances of success.
References
[1] NIELSEN J., 1993- Usability Engineering, Academic Press,
San Diego, California. [2] SHONIREGUN C.A.; GRAY S.J., 2003- Is E-learning really
the future or a risk?, ACM Ubiquity, 4(10), ACM publisher..
[3] ARDITO C., 2003- Systematic Evaluation of e-Learning
Systems: An Experimental Validation, NordiCHI 2006:
Changing Roles, 14-18 October, Oslo, Norway.
[4] Blackbord Academic Suite- http://www.blackboard.com.
[5] Moodle - http://www.moodle.com.
[6] KRUSE K., 2003- Effective User Interface Design.
Dr. Ikbal Arab
24
http://www.learningcircuits.org/may2000/may2000_webrules.
[7] ARDITO C., 2004- Usability Testing of E-Learning Tools,
AVI '04, Gallipoli (LE), May 25-28, Italy.
[8] NIELSEN J., MOLICH R., 1990- Heuristic Evaluation of
User Interfaces, In Proceedings of CHI 90, pp. 249–256.
[9] NIELSEN J., 1994- Heuristic Evaluation - Usability
Inspection Methods, John Wiley Publishing, New York.
[10] WHARTON C., LEWIS C., POLSON P., 1994- The Cognitive
Walkthrough Method: A practitioner’s guide. In Nielsen J.
and Mack, R.L. (Eds) Usability Inspection Methods. New
York: John Wiley & Sons, Inc.
[11] ARAB I., 2009- Comparative Usability Studies of two E-
learning Platforms Employing Observational User Testing.
Research Journal of Aleppo University - Engineering Science
Series, 60.
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
52
Studying the Effects of Angle Variances of Lighting
Lamp on Illumination Flow Distribution Riad Al-Mostafa*, Ahmad Kussay Kayyali**, Abir Ali Al-Jarbouh***
* Dept. of Electrical Power System, Faculty of Electrical and Electronic Engineering,
University of Aleppo
**Dept. of Electronic Engineering, Faculty of Electrical and Electronic Engineering,
University of Aleppo
***Postgraduate Student (MSc.) Dept. of Electrical Power System, Faculty of
Electrical and Electronic Engineering, University of Aleppo
Abstract
Studying the electrical lighting and choosing the kind of lamps
is one of the most important factors in the realization of a good
lighting. So the extended efforts in lighting art are run to obtain an
industrial light very similar to daylight and which can replace it.
During studying lighting in any place, we must pay attention to the fact
that lighting gives the studied place features according to lighting kind,
because good lighting makes the study place more visual.
External lighting of playgrounds is a complete separate science
and its study must be accurate to get a good lighting distribution and
lighting levels according to IEEE.
Also, suitable lighting in playgrounds should be provided in
order to make visibility and movement easier for players, and it must
be proper in order to allow monitoring cameras and TV to record the
matches accurately and clearly. It is also important that it does not
make bad shadows of players because of irregular distribution of
illumination lights in the playground. Illumination lighting must not be
very glary so the lights should be high and must be like daylight and
with wide lumen intensity and high output, and the best illumination
light is Metal Halide lamps.
We used an equation in direct lighting calculations for making
speed calculations to know lighting levels in specific points, but now
we can use computer to get the best results. Lighting in playgrounds
requests different conditions according to the nature of the place,
whether used to local, Olympic or international games. So some
international organizations defined levels of horizontal and vertical
lighting for all playgrounds; for example, Germany defined the vertical
level for about 1000 lux and the horizontal one for about 1500lux.
Received 14/12/2009
Accepted 13/1/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
27
Influence of the Pocket Form on Stability of Hybrid
Journal Bearing
Ahmad Al Sayed , Mohammed Al Bakkar* Dept. of Materials Engineering, Faculty of Mechanical Engineering,
University of Aleppo
*Postgraduate Student (MSc.) Dept. of Applied Mechanics, Faculty of Mechanical
Engineering, University of Aleppo
Abstract
When the hybrid journal bearing contains a number of pockets
through which the lubricant is fed with high pressure, the action of
load results from hybrid action between this pressure and the
hydrodynamic pressure, resulting from the relative movement of
surfaces. So this journal bearing is named hybrid journal bearing.
In this study, the dynamic coefficient was calculated using a
different form of pocket (Rectangular, circular, triangular, trapezoid
and oval).
The numerical method used finite volume method; this method
is considered the newest numerical method used in the lubrication.
Received 23/3/2009
Accepted 11/1/2010
Res. J. of Aleppo Univ. Engineering Sciences Series No.78 2010
29
Adaptive Backstepping-Assisted MRAS for Speed
Control of DC Motor Drives
Abdul Kader Joukhadar , Ahmad Ammar Naassani ,
M. Samir Nawlo* Dept. of Electronics, Faculty of Electrical & Electronic Engineering,
University of Aleppo
*Postgraduate Student (MSc.)
Abstract
The aim of this paper is to design a robust control system using
Adaptive Backstepping Controller which is integrated with MRAS for
controlling the speed of DC motor drives for wide speed range and
under variable load torque. The design of the backstepping is achieved
by building an error equation between reference speed and actual rotor
speed. The aim is to force the error to converge to zero asymptotically,
using Lyapunov Function and “Virtual Control”, to regulate rotor
speed and obtain global stability for proposed DC drive system under
two cases; for linear load torque change; and for sudden change in the
load torque. This approach is based on the use of non-linearities in the
model of DC motor with both electric and mechanical dynamics.
A full derivation of a backstepping controller which presented
the effectiveness of the proposed controller has been verified by
simulation results in Matlab/Simulink. It has been shown that the
proposed controller provides high dynamic response and robustness
against system parameter uncertainty.
Received 8/11/2009
Accepted 19/1/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
13
Comparative Study of Tombstones Transformation
Functions Ikbal Arab, Mazen Saaid, Rym Khawam*
Dept. of Computer, Faculty of Electrical Engineering, University of Aleppo
*Postgraduate Student (MSc)
Abstract
The collaborative editing has recently got a very important role
in achieving the jobs of people and enterprises as well as in the
electronic encyclopedia WIKIPEDIA and the USENET.
In this paper, we are interested in TTF (Tombstones
Transformation Functions) used in collaborative editing in peer-to-peer
network which maintains consistency of shared documents copies and
preserves the effects of generated operations such as inserting and
deleting from any local site sent to all remote ones. These functions do
not require a central site and allow working off-line.
Our work is established on two different classes of algorithms
(U)ncompacted TTF Model and (D)elta TTF Model. We applied
them on a simple structure of Data: Linear string. Obtained results are
compared using complexity of code and processing time.
As a result, we clarify that using TTF is revealed as a suitable
function to apply in the internet.
Received 22/10/2009
Accepted 20/1/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
33
Numerical Study on the Effect of RSW Process
Parameters on Characteristics of Weld-Bonded joints
Using FEM
M. Jameel Alshehne*, Ahmad Almansour*, Abdulhadi Ammory** * Dept. of Materials Engineering, Faculty of Mechanical Engineering
**Postgraduate Student (MSc.), Faculty of Mechanical Engineering,
University of Aleppo
Abstract
The Resistance Spot Welding (RSW) has become one of the
most important applications in the industrial robots, especially in the
field of manufacturing vehicles. Other applications in which RSW
robots are used contain manufacturing airplanes, railway cabins,
agricultural machines, frames of motor scooters and bicycles, heavy
vehicles, and other various applications.
In view of the importance of the RSW and complexity of
performing all tests and getting the practical results in this paper, a 2D
numerical study of Resistance Spot Welding process has been
employed on two metal plates. The model was analyzed mechanically
and thermally. Furthermore, three-dimensional (3D) finite element
model has been established to study the failure of spot-welded joints
under shear loading.
The numerical results were compared with the experimental
load-displacement curve that resulted from applying tension test on
samples prepared and welded through Resistance Spot Welding
machine. The agreement between numerical and experimental results
was obvious. Hence, the present research made a contribution to
analyzing RSW process numerically and the model was successful.
Received 22/11/2009
Accepted 21/1/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
53
New Method to Enhance the Performance of Mobile AD
HOC Networks
A. Abou Hajar, B. Barmada, Eng. R. Teirouz *
Dept. of Communication, Faculty of Electrical & Electronic Engineering,
University of Aleppo
* Postgraduate Student (MSc)
Abstract An ad hoc network is a collection of wireless mobile nodes
dynamically forming a temporary network without the use of any
existing network infrastructure or centralized administration.
Because of the nature of ad hoc networks, there are special
demands for ad hoc routing protocols. This paper proposes an
improvement to the original dynamic source routing (DSR) protocol
used in ad hoc networks. In the suggested method, the route error
message is broadcast to all sources nodes in the network which have
got the broken link in the route cache, when a broken link happens in
the network.
The efficiency of the proposed method on the DSR protocol is
evaluated and compared with the original DSR protocol using
Glomosim simulator.
The results show that the proposed method achieves better
performance than that of the dynamic source routing protocol in terms
of the delivery ratio of Packets and the overhead for the number of
nodes from 10 to 70 and for packets size from 64 bytes to 1024 bytes,
where most of the ad hoc networks fall within these ranges.
Received 15/9/2009
Accepted 21/1/2010
Res. J. of Aleppo Univ. Engineering Science Series No.78 2010
73
The Thermodynamic Study of Adsorption Refrigeration
System and Effect of Operating and Design Parameters
on its Performance
Nabhan Khayata Dept. of Power, Faculty of Mechanical Engineering, University of Aleppo
Abstract
The increasingly soaring price of fossil fuel, the fear that it
would run out, the environmental pollution resulting from the use of
this fuel, and the increasing demand for electrical energy urged
researchers to find new sources of natural and clean energy.
The refrigeration and air conditioning are the necessities of
modern life, and they are considered the main applications of energy-
consuming. This research has focused on the importance of thermally
powered refrigeration systems, in particular adsorption refrigeration
systems, which are based on adsorption technology of refrigerant on
adsorbent, a result of thermal energy conversion (solar energy, other
thermal sources) to cooling effect.
In addition, the basic cycle of adsorption refrigeration systems
has been studied. Also, the thermodynamic analysis of their main
components has been accomplished. Mathematical molding for
adsorption refrigeration system, using working pair (activated
carbon/methanol) for calculation and evaluation coefficient of
performance COP, has been presented. The effect of operation and
design parameters on performance system has been studied. The
results were processed through illustrations and graphs, and were
compared with results of similar works.
Keywords: Adsorption refrigeration, Adsorbent, Adsorbate (refrigerant), coefficient of
performance
Received 31/12/2009
Accepted 24/1/2010
Res. J. of Aleppo Engineering Science Series No. 78 2010
93
Determining the Optimum Parameters for the Grinding
Process of Fish Feed
Imad Antibas Dept. of Agricultural Machinery Engineering, Faculty of Mechanics, University of
Aleppo
Abstract
In the present research, the protein material was extracted from
the fluid of vegetables roots and was utilized later as fish feed instead
of the flour of meat, bones and soy beans. A mathematical and
physical model was established for the process of fluidizing
(squeezing) the vegetables roots. The pressure to get green fluid, the
diameter of the holes of squeezing chamber and the time needed for
the process were determined.
The technological process for forming the feed pellets was
studied and the optimum values influencing this process were
determined. As a result, it was obvious that at relative humidity
between 29 and 30%, motion speed between 0.01 and 0.03 m/s,
pressure of 5 MPa, and water temperature of 80 C, the friction factor
and the energy were least and minimum and the productivity was
maximum.
It was understood that the dissolution of the material containing
the vegetables roots in the water is less than the dissolution of the
material containing the meat flour. The research also revealed that
using the feed containing the protein extracted from vegetables roots
has an equal effect on the growth of the fishes but with less cost by
25%.
Received 7/1/2010
Accepted 26/1/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
14
Enhancement of Release System Using Visual Optical
Imaging
Nidal Duya, Nizar Ajib, Abdul Mannan Habib* AL Assad Academy for Military Engineering, Electro Mechanical College
*Postgraduate Student (MSC)
Abstract
This research aims to enhance performance of automatic
release system using visual optical imaging. The captured images of
targets process and the coordinate of targets were determined in each
image, and the correlation between the sequence images was studied to
obtain predictable movement of the target. That was done through
implementation of frames difference algorithm for this sequence in
order to obtain the value of the displacement for giving it to the motors
of automatic release system, so as to follow up the target required to be
affected.
This research proposes a method to predict the movement of
the target to determine and predict the coordinate of the center of the
target in any moment. That was done by depending on the use of
sequential images in certain intervals of time, where an image of the
required target to be affected was picked, and after certain time, a
second image was picked, and the system calculated the difference
between the two images. Then movement track and place of the target
were predicted after a certain interval of time to direct the gun to that
position and give command for shooting when the target reaches that
position.
Through this research, all stages were reviewed from the
moment of image capturing by the camera to the stage of guidance and
release.
Program has been written in an environment of Matlab, the
coordinate of center of target was calculated, and then orders to the
enforcement motors and release unit were given, to enforce the
required task from system.
Received 13/10/2009
Accepted 27/1/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
34
Three Dimensional Animation of Industrial Robot
Kinematics
M. Dubsi* , A. G. Shehabi
** M.Tair
***
*Dept. of Applied Mechanics, Faculty of Mechanical Engineering,
University of Aleppo
** Dept. of Aeronautical Engineering, University of Aleppo
***Postgraduate Student (MSc.) Dept. of Production, Faculty of Mechanical
Engineering, University of Aleppo
Abstract
Robot modeling and simulation processes are considered
important steps in analyzing and visualizing both geometric and
dynamic processes that the robot performs. In this research the
derivation of mathematical model of indusial robot for arc welding will
be investigated. The simulation in three dimensional space within
Matlab environment will be performed in order to be able to design
control system. The outcome results showed the importance of
simulation process when the study of robot kinematical study is
required either using direct method or inverse one. The simulation
process showed the smooth and stable motion of robot. Keywords: modeling, simulation, robot, kinematical study
Received 21/12/2009 Accepted 28/1/2010
Res. J. of .Aleppo Univ. Engineering Sciences Series No. 78 2010
45
Designing and Simulating the Performance of a Hybrid
Renewable Energy System by Using Photovoltaic and
Fuel Cells
Mohamad Jalal Tarmanini*, Mohamad Dakak**,
Faisal Alalloush*** *Dept. of Electronic Engineering, Faculty of Electronic Engineering,
University of Aleppo
** Scientific Studies research centre
***Postgraduate Student (Msc) , Dept. of Electronic Engineering, Faculty of
Electronic Engineering, University of Aleppo
Abstract
The article provides the results of a scientific research to design
and study the performance of hybrid renewable energy system (Photovoltaic
system with fuel cells system) to feed an electronic telephone exchange
centre in a rural area. The hybrid generation system which was
independent of the public network was designed and simulated to feed
telephone exchange equipment as DC load. Photovoltaic system was
used as an energy source to feed the load during the day while hydro-
gen generation and fuel cell system was used to feed the load at night,
and in low solar radiation during the day as an energy source or as a
secondary storage of energy. Hybrid system and its control mechanism
was discussed and described using the HOMER program to design and
simulate the system electrically with calculating the size and cost of
the system in ways of optimal solution. Simulation results showed the
effectiveness of using fuel cell system with the Photovoltaic system to
feed the telephone exchange as an independent electrical load, and the
economic feasibility of this system was studied in order to assess the
cost in the Syrian Arab Republic. The results were very encouraging to
implement development plans in investing renewable energies with
low-cost, in comparison with the generation systems used currently. Keywords: hybrid system, renewable energies, Photovoltaic system, fuel cells,
electrolyzer, modelling and simulation, the economic cost.
Received 30/12/2009
Accepted 2/2/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
47
Designing and Simulating Rf Filters
Using the Scattering Parameters (S-Parameters)
Khalaf AL Abdullah, Oroba Faraj AL Ali, Mesoun Shaheed * Dept. of Electronic Engineering, Faculty of Electrical and Electronic Engineering,
University of Aleppo
* Postgraduate Student (M.Sc)
Abstract
The main objective of this thesis is to study the use of S-
parameters in simulating and designing passive Rf filter (Frequency
Above 300MHZ). We designed the filter of insertion-loss method
(ILM), which depends on low-pass prototype (LPP) to begin the
design, then we simulated this filter for getting the Scattering
Parameters (S-Parameters), and finally we converted it to Impedance
Parameters (Z-Parameters).
This study is useful for many Radio and Microwave
applications; for example, transmission line matching, distribution of
signal on all loads, design of radio and microwave device, etc.
Received 28/10/2009
Accepted 3/2/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
49
Integrated System Using Advanced Speech Processing
Technologies
Yahya Najjar Dept. of Computer Engineering, Faculty of Electrical & Electronic Engineering,
University of Aleppo
Abstract
Most systems are available for discrimination and speech
processing techniques based on a Hidden Markov Models (HMMs),
Neural Networks (NNs), Dynamic Time Warping (DTW), or a
combination of two techniques mentioned to overcome the weaknesses
in one of the techniques. In our research, we used a combination of
these three techniques to improve system performance and increase the
accuracy in discrimination, reaching an average of 99,882%. We
invested the Microsoft's speech package code for designing program to
control some of the operating system interfaces, as well as voice-based
edited interface to dictate and save files in English or Arabic, and
convert the typed text or the one dictated-to-speech.
Keywords: speech recognition, HMMs, NNs, DTW.
Received 31/12/2009
Accepted 8/2/2010
Res. J. of Aleppo Engineering Science Series No. 78 2010
15
Studying the Effect of Intermediate Diaphragms on the
Elastic and Elastic –Plastic Behavior of Simple Span
Prestressed Concrete Highway Bridges
Abdul Qader Melhem, Mike Saad* Dept. of Structural Engineering, Faculty of Civil Engineering, University of Aleppo
*Postgraduate Student (MSc.)
Abstract
The standard specifications for highway bridges (AASHTO
2004) recommend that intermediate diaphragm be used at the point of
maximum positive moment for spans in excess of 12m, and when the
span exceeds 25m, two intermediate diaphragms should be placed.
Clear reasons for such requirements were not given.
While the intermediate diaphragms could provide protection for
longitudinal girder when overloaded truck passes the bridge, by
distributing vertical live loads between girders, and reduce maximum
deflection and moment for each individual girder, it is not included in
structural calculations. This paper studies the influence of intermediate
diaphragm on the elastic- plastic behavior of prestressed precast
concrete girders of highway bridges till reaching the failure point, and
discusses its effects when different distance between longitudinal
girders is presented.
Received 30/9/2009
Accepted 15/2/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
35
Analytical Study for the Situation of Post Graduate
Studies at Civil Engineering College from Viewpoints of
Its Staff
Nidal Shehadeh*, Maher Ghazal **, Malla Dej*** *Dept. of Geotechnical Engineering, Faculty of Civil Engineering,
University of Aleppo
**Dept. of Construction Management, Faculty of Civil Engineering,
University of Aleppo
***Postgraduate Student (MSc.) Dept. of Construction Management, Faculty of Civil
Engineering, University of Aleppo
Abstract
This research has been conducted in the civil engineering
college in Aleppo University to study the situation of post graduate
studies from the viewpoint of its staff. The researcher depended in his
study on the model of the syllabus file of post graduate studies and a
questionnaire was distributed to the staff of post graduate studies at the
Civil Engineering College. The model of the syllabus file contained
eight main items: fundamental information, general objectives for
syllabus, intended learning outcomes, content of syllabus, manner of
education and learning, manner of students’ evaluation, list of books
and references, and the requested abilities for education and learning.
The results were analyzed and discussed in this research to determine
the weakness and strength points of post graduate studies. Some of the
weakness points included the shortage of specialized books in library,
and the lack of funds allocated for financing scientific research.
Received 2/1/2010
Accepted 17/2/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
55
Study of Electrical Faults in Electricity Network of
Tension 66 KV in the Province of Hasaka, Their Causes,
and the Performance of Protection Devices Applied to
Them
Sami Altrsha, Nasr Alkasem, Ahmed Al-Tahir* Dept. of Electrical Energy, Faculty of Mechanical and Electrical Engineering,
University of Baath
*Postgraduate Student (PhD)
Abstract
In this research, scientific methodology to study and analyze
the electric grid failures has been used and applied in the analytical
study of crashes experienced by the different electrical grids with 66
KV tension in the province of Hasaka, showing causes, types and
phenomena associated with the emergence of fault in the electricity
network. Then the research indicated the performance of devices
protection applicable to all different kinds, and we have prepared a
computer program to automate the systems of the studied network.
Received 6/1/2010
Accepted 21/2/2010
Res. J. of Aleppo Univ. Engineering Science Series No.78 2010
57
Retrieval Information from E-Learning System
Kinda Abou Kaseem Dept. of Computer Engineering , Tishreen University
Abstract
We worked hard through this research to study the standards of
e-learning systems and then depended on the SCORM standard to
build SCORM compliant learning content. From the
“imsmanifest.xml” file of the learning content, we stored the learning
content within learning object database.
The process of gathering content nodes within clusters
(according to similarity threshold (T=0.813) of content tree consisting
of 41 text files) has resulted in decreasing research process cost as well
as speeding the process of reaching the desired content node (It has
saved about 50% of research processes). Decreasing the depth of
content tree that consists of 41 text files distributed in six levels
(L0…L5) has contributed to decreasing the number of nodes in which
a comparison process has been done at approximately the rate of (1/4)
and decreasing research process at approximately the rate of (1/4).
Key words: E-Learning, SCORM standard, Research Algorithm Approximation
similarity.
Received 12/1/2010
Accepted 21/2/2010
Res. J. of Aleppo Univ. Engineering Science Series No. 78 2010
59
Computing the Maximum Value of Twisting
Factor Accompanying Torsion in Plate
Ammar Onabi Dept. of Structural Engineering, Faculty of Civil Engineering,
University of Aleppo
Abstract
Many references have treated the problem of computing the
shear stresses resulting from twisting; they introduced several solutions
for different sections in different ways based on accuracy, yet most of
them have not considered the case of twisting in plates forming the
section.
One of the new methods to compute these stresses is the
median line mode method which has introduced the concept of
twisting factor; however, this method assumes constant value of means
that the effect of plate thickness on twisting factor is negligible.
In this research, we have introduced a method for computing
twisting stresses accompanying torsion applied on a plate with full
solid web. This method is based on the median line model and then we
have developed the equations to compute the twisting factor taking
into consideration the thickness of the plate.
A practical example was carried out; its results were compared
with the results of one of the old methods. Through this we have
displayed an easy, fast, and approximate way derived from the first
method. Finally, comparison has been made between these two
methods.
Received 15/10/2009
Accepted 23/2/2010
Res. J. of Aleppo Univ. Engineering Science Series No.78 2010
61
The Structural Health Monitoring of Structures
(Plates) by Means of Measuring Their Vibrations
Abdul Alim Dib Dept. of Structural Engineering, Faculty of Civil Engineering,
University of Aleppo
Abstract
Plates and slabs are very important structural elements in Civil
engineering (roofs of buildings and decks of bridges), mechanical
engineering (wings of planes) and space engineering (elements in
space shuttles).
The Structural Health Monitoring with the help of vibration
measurement has become more and more important because it prevents
disasters via strengthening damaged elements before they fail and
because of the ineffectiveness of the other methods such as radiation
and sound waves.
One method of vibration measurement is based on comparison
of the analytical outcomes of natural frequencies and mode shapes of
the building versus experimental outcomes of natural frequencies and
mode shapes.
Another method is based on the comparison of the natural
frequencies and mode shapes resulting from measurements taken at
different periods.
This paper is concerned with an analytical study about the
precision, accuracy and authenticity of the shape- curvature- method
for mode shapes in the prediction of damage (and/or cracks) and its
location in plates and slabs.
The slab in the current study is a steel plate model fixed in all
sides. The analysis of the undamaged and damaged models is
calculated by the ANSYS 10 software. The cracks in the plate were
made and arranged artificially in different places.
The cracks were identified and located by analytical
calculations due to vibration measurement then compared with the real
existing cracks on the plate. Key Words: Damage Detection und Localization, Structural Health Monitoring,
curvature method of the mod shapes
Received 8/11/2009
Accepted 23/2/2010