Browsing by Author "Yimam, Abubeker"

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    Adaptive Control Design for a MIMO Chemical Reactor
    (Addis Ababa University, 2004-07) Yimam, Abubeker; Venkatanarasaiah, D. (PhD)
    The major disadvantage of non-adaptive control systems is that these control systems cannot cope with fluctuation in the parameters of the process. One solution to this problem is to use high levels of feedback gain to decrease the sensitivity of the control system. However high gain controllers have two major problems: large signal magnitude and closed loop instability. The solution to this problem is to develop a control system that adapts to changes in the process. This paper presents the design of adaptive controller to a MIMO chemical reactor. The proposed adaptive controller is tested by using Math lab Simulink program and its performance is compared to a conventional controller for a different situation. The paper demonstrated that while the adaptive controller exhibits superior performance in the presence of noise the convergence time is typically large and there is a large overshoot. To resolve these problems of adaptive controller, the proposed controller is redesigned by modifying the adaptation law. And the results show a significant improvement in the performance of the adaptive controller without excessive increase in the adaptation rate. life of the low and middle income inner-city residents of Addis Ababa. Financial, institutional and legal problems are also seen as the major problems that hinder the implementation of LDPs in Addis Ababa
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    Online Amharic Word Processor for Mobile Phones
    (Addis Ababa University, 2013-03) Yimam, Abubeker; Midekso, Dida (PhD)
    Nowadays, accessing of web information and services at anytime from anywhere is becoming realistic using WAP enabled mobile devices. Mobile device users become rapidly growing from time to time. In this thesis, an online Amharic word processor for mobile phone is designed and developed by considering the physical screen size, scripting language, text entry method of mobile phones and nature of Amharic script. In order to design and implement the OLAWP, it is necessary to obtain the visiting mobile phone capability attributes information first. The attributes that are used in this study are mobile phone physical screen height and status about whether the mobile phone supports client-side scripting language or not. These capability attributes are obtained from the WURFL DDR in the cloud which is used to detect and return the mobile phone capabilities to our site. The returned values are stored and used as an input in the design of the word processor interface, to select the type of the virtual keyboard and style sheet used, and to decide the scripting language used. The OLAWP site is designed and implemented to enable users to prepare simple Amharic documents wherever they go as far as the WAP enabled mobile phones exist at their hand and the Internet infrastructure exist. In the design of OLAWP, the major activities are device detection and redirection to the compatible page, user and file manager, designing of the word processor interface by loading appropriate virtual keyboard. In this work, the mobile phones are categorized into three groups: small, medium and large, and the Amharic virtual keyboard is grouped into small and large based on the mobile phone screen height. Small mobile phones used small type of Amharic virtual keyboard and other groups used the large Amharic virtual keyboard. Finally, the OLAWP prototype evaluation is conducted through questionnaire by participating 15 different users in various types (in screen size, text entry method, browser and brand) of mobile phones. The evaluation result showed that better satisfaction and performance on some mobile phones which are touch based, and UC and Android browsers mobile phones compare to keypad based and Opera mini browser mobile phones. Keywords: Amharic keyboard, Amharic word processor, mobile cloud service, mobile Amharic word processor, mobile virtual keyboard, online word processor, Wireless Application Protocol
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    Online Amharic Word Processor for Mobile Phones
    (Addis Ababa University, 2013-03) Yimam, Abubeker; Midekso, Dida (PhD)
    Nowadays, accessing of web information and services at anytime from anywhere is becoming realistic using WAP enabled mobile devices. Mobile device users become rapidly growing from time to time. In this thesis, an online Amharic word processor for mobile phone is designed and developed by considering the physical screen size, scripting language, text entry method of mobile phones and nature of Amharic script. In order to design and implement the OLAWP, it is necessary to obtain the visiting mobile phone capability attributes information first. The attributes that are used in this study are mobile phone physical screen height and status about whether the mobile phone supports client-side scripting language or not. These capability attributes are obtained from the WURFL DDR in the cloud which is used to detect and return the mobile phone capabilities to our site. The returned values are stored and used as an input in the design of the word processor interface, to select the type of the virtual keyboard and style sheet used, and to decide the scripting language used. The OLAWP site is designed and implemented to enable users to prepare simple Amharic documents wherever they go as far as the WAP enabled mobile phones exist at their hand and the Internet infrastructure exist. In the design of OLAWP, the major activities are device detection and redirection to the compatible page, user and file manager, designing of the word processor interface by loading appropriate virtual keyboard. In this work, the mobile phones are categorized into three groups: small, medium and large, and the Amharic virtual keyboard is grouped into small and large based on the mobile phone screen height. Small mobile phones used small type of Amharic virtual keyboard and other groups used the large Amharic virtual keyboard. Finally, the OLAWP prototype evaluation is conducted through questionnaire by participating 15 different users in various types (in screen size, text entry method, browser and brand) of mobile phones. The evaluation result showed that better satisfaction and performance on some mobile phones which are touch based, and UC and Android browsers mobile phones compare to keypad based and Opera mini browser mobile phones. Keywords: Amharic keyboard, Amharic word processor, mobile cloud service, mobile Amharic word processor, mobile virtual keyboard, online word processor, Wireless Application Protocol