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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


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?


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


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.


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


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.


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


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)


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,


**Dept. of Electronic Engineering, Faculty of Electrical and Electronic Engineering,


***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


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,


*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,


*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


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


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,


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


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,


* 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


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


34

Three Dimensional Animation of Industrial Robot

Kinematics

M. Dubsi* , A. G. Shehabi

** M.Tair

***

*Dept. of Applied Mechanics, Faculty of Mechanical Engineering,


** Dept. of Aeronautical Engineering, University of Aleppo

***Postgraduate Student (MSc.) Dept. of Production, Faculty of Mechanical


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,


** 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


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,


* 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


49

Integrated System Using Advanced Speech Processing

Technologies

Yahya Najjar Dept. of Computer Engineering, Faculty of Electrical & Electronic Engineering,


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


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,


**Dept. of Construction Management, Faculty of Civil Engineering,


***Postgraduate Student (MSc.) Dept. of Construction Management, Faculty of Civil


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


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


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


59

Computing the Maximum Value of Twisting

Factor Accompanying Torsion in Plate

Ammar Onabi Dept. of Structural Engineering, Faculty of Civil Engineering,


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


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,


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

research journal of aleppo university - alepuniv.edu.sy · dr. ahmad al sayed mohammed al bakkar...

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