Volume 104 No 4
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Table of Contents & Guest editorial (~126 kB)
1. A Computer Based Assessment System for Undergraduate for Electrical Engineering Modules
2. An Improved Fundamental Design Influencing Methodology in a Constrained Project Management Environment
3. A CCH Cycle Adaptive Algorithm for IEEE 802.11P Mac Protocol in Safety Applications
4. Spatial-Spectral Watermarking Scheme for JPEG Steganography
A Computer Based Assessment System for Undergraduate for Electrical Engineering Modulesby
By P.A. van Vuuren, A. Alberts and L. Hager
Abstract: Good assessment is an essential component of good learning. Marking test and exam papers for large classes is however a time-consuming and repetitive task. This paper reports on the design and implementation of a computer based assessment (CBA) system suitable for undergraduate engineering modules. This prototype CBA system is capable of automatically grading relatively open-ended analysis and design problems and is also relatively user friendly. This CBA system consists of two separate subsystems, namely a test delivery subsystem and an automatic grading subsystem (which is the contribution of this paper). Automatic grading of the student answer papers is performed in Matlab. The grading subsystem can automatically grade typed student answers containing symbolic mathematical expressions as well as numeric answers. Grading is performed accurately, consistently and very fast compared to a human lecturer. Students are given partial credit for partially correct answers and feedback is given in a very intuitive form quite close to the traditional manner in a pen-and-papertest. The system has been successfully used to take final exams in a second year engineering module on basic circuit analysis.
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An Improved Fundamental Design Influencing Methodology in a Constrained Project Management Environment
By A. Wessels and L. Pretorius
Abstract: The aim of this paper is to develop conceptually from literature an improved design influencing concept in a constrained project management environment. The project management and systems engineering interface pertaining to project cost and schedule has been researched. Design as part of Systems Engineering (SE) and Project Management (PM) is an important process for product development. The interaction between SE and PM can influence the success of a product development project. A model has been developed to better understand why design iterations are fundamental to the design process. This model has been expanded into a constrained design influencing model that provides a better understanding of the influence of project management in the design process. This model shows that the project manager, particularly if he is under unrealistic constraints, can force a premature design release for integration to the next system level. This model helps to provide a fundamental understanding of the design process.
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A CCH CYCLE ADAPTIVE ALGORITHM FOR IEEE 802.11P MAC PROTOCOL IN SAFETY APPLICATIONS
By L. Miao, K. Djouani, B. van Wyk and Y. Hamam
Abstract: The IEEE 802.11p standard, especially the 802.11p MAC protocol, has attracted much attention as part of the WAVE protocol in VANETs. Safety applications are very challenging for the design of MAC protocols due to their low latency and high reliability requirements. The CCH interval is also a key parameter for the 802.11p MAC protocol since it can affect the performance of delivering safety messages significantly. In this paper, a simulation based evaluation is proposed firstly to evaluate the performance of the 802.11p MAC protocol with various vehicle densities and CCH interval settings. Based on the simulation results, a CCH cycle adaptive algorithm for the 802.11p is then proposed. In this, the CCH interval is adjusted according to the vehicle density. The simulation results show that the proposed algorithm outperforms the IEEE 802.11p MAC protocol in terms of channel utilization and reliability in safety applications.
Spatial-Spectral Watermarking Scheme for JPEG Steganography
By Bradley Marques, Benjamin Sim and L. Cheng
Abstract: Steganography is the art of concealing the presence of a communication, across an open channel, from undesired parties. This is achieved by the encoding of message data in innocuous cover objects, such as JPEG digital images. Many JPEG steganography algorithms exist; most perform the encoding in the spectral domain of the image. A new steganographic method, deemed the Spatial-Spectral Watermarking Scheme (SSWS), has been developed and utilises both the spatial and the spectral domains for the encoding process. A developed mathematical model of the scheme predicts a maximum gain in terms of steganographic capacity of 4.9 over an existing algorithm, JSteg. Experimental data obtained from a software prototype confirms this result. Furthermore, the experimental data confirms that the securities in the spatial domain and the spectral domain are inversely proportional to the information amounts embedded in these two domains.
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