Browsing Electrical Engineering by Publication Date

Now showing items 21-40 of 2414

    • A new iterative learning control method for PWM inverter current regulation 

      Ben-Brahim, Lazhar; Benammar, Mohieddine; Alhamadi, Mohd A. ( IEEE , 2003 , Conference Paper)
      AC servomotor speed or current controller based on PI control and/or optimal control, can not eliminate the cyclical fluctuations of speed or current when subject to periodic disturbances. PWM inverters output waveforms ...

    • Digital control for UPS inverters 

      Ben-Brahim, Lazhar; Yokoyama, Tomoki; Kawamura, Atsuo ( IEEE , 2003 , Conference Paper)
      PWM inverters digital controls with dead-beat re sponse, for UPS applications, are reviewed. To improve the output waveforms of the PWM inverter, several modern control techniques are applied together with the deadbeat ...

    • Performance enhancement of relay-assisted communications via binary feedback 

      Hasna , Mazen ( IEEE , 2004 , Conference Paper)
      This paper proposes a modified two-hop wireless communication system and studies its performance. The modified system has a reliable feedback channel that carries a binary signal from the receiver to inform the transmitter ...

    • Optimal power allocation for relayed transmissions over Rayleigh-fading channels 

      Hasna , Mazen; Alouini M.-S. ( IEEE , 2004 , Article)
      Relayed transmission is a way to attain broader coverage by splitting the communication link from the source to the destination into several shorter links/hops. One of the main advantages of this communication technique ...

    • Performance of OFDM with M-QAM modulation and optimal loading over rayleigh fading channels 

      Digham F.F.; Hasna , Mazen ( IEEE , 2004 , Conference Paper)
      We present optimum bit and power loading algorithms for orthogonal frequency division multiplexing (OFDM) systems using an M-ary quadrature amplitude modulation (M-QAM) scheme. Several scenarios for the amount of channel ...

    • A performance study of dual-hop transmissions with fixed gain relays 

      Hasna , Mazen; Alouini M.-S. ( IEEE , 2004 , Article)
      This letter presents a study on the end-to-end performance of dual-hop wireless communication systems equipped with nonregenerative fixed gain relays and operating over flat Rayleigh-fading channels. More specifically, it ...

    • Precise method for linearizing sine and cosine signals in resolvers and quadrature encoders applications 

      Alhamadi, Mohd A.; Benammar, M.; Ben-brahim, L. ( IEEE , 2004 , Conference Paper)
      Resolvers and quadrature encoders provide electrical signal related to the sine and cosine of the mechanical shaft angle over the full 360 degree range. A converter is described for the linearization of these signals, ...

    • Design and Assembly of Miniature Zirconia Oxygen Sensors 

      Benammar, M. ( IEEE , 2004 , Article)
      Zirconia oxygen sensors are highly selective solid-state devices used for many applications, including combustion control for better fuel economy and lower emissions. Stabilized zirconia electrolyte meets the device ...

    • A Novel Resolver-to-360° Linearized Converter 

      Benammar, Mohieddine; Ben-Brahim, Lazhar; Alhamadi, Mohd A. ( IEEE , 2004 , Article)
      A novel and simple resolver-to-dc converter is presented. It is shown that by appropriate processing of the sine and cosine resolver signals, the proposed converter may produce an output voltage proportional to the shaft ...

    • Average outage duration of multihop communication systems with regenerative relays 

      Yang L.; Hasna , Mazen; Alouini M.-S. ( IEEE , 2005 , Article)
      Closed-form expressions for the average outage duration (AOD) of multihop regenerative communication systems over generalized fading channels are presented. Both noise-limited and interference-limited systems are studied. ...

    • On the capacity of cooperative diversity systems with adaptive modulation 

      Hasna , Mazen ( IEEE , 2005 , Conference Paper)
      In recent years, cooperative diversity systems have gained increased attention in the literature as a new way of combating the effect of signal fading. In this paper, we investigate the performance of these systems when ...

    • Precise, wide-range approximations to arc sine function suitable for analog implementation in sensors and instrumentation applications 

      Benammar, M. ( IEEE , 2005 , Article)
      This paper presents four newly developed algebraic approximations of the inverse sine function, defined for the full [-1,+1] input range. These approximations contain few terms, and have numerical coefficients with low ...

    • A high precision resolver-to-DC converter 

      Benammar, Mohieddine; Ben-Brahim, Lazhar; Alhamadi, Mohd A. ( IEEE , 2005 , Article)
      A newly developed resolver converter, providing a pseudolinear voltage proportional to the shaft angle, is presented. This converter is based on a new concept involving the absolute values of the demodulated sine and cosine ...

    • Channel assignment of microcellular mobile radio networks 

      Abdel-Naby M.; Nofal M.; Khames S.; El-Khoby H.; Hasna , Mazen ( Institute of Electrical and Electronics Engineers Inc. , 2006 , Conference Paper)
      This paper addresses the analytical and simulation modeling of non overlapping microcells with both non-prioritized and prioritized handover schemes. The network performance is analyzed in terms of the analytical results ...

    • A novel converter for sinusoidal encoders 

      Benammar, Mohieddine; Ben-brahim, Lazhar; Alhamadi, Mohd A.; El-Naimi, Mohamed ( IEEE , 2006 , Conference Paper)
      The paper presents a novel and low cost method for determining the angle from sine and cosine signals generated by angular position sensors such as resolvers and sinusoidal encoders. The proposed scheme is based upon the ...

    • A neutral point voltage balancing method for multi-level GTO inverters 

      Ben-Brahim, Lazhar ( IEEE , 2006 , Conference Paper)
      The balancing problem of the DC-link capacitor voltage is inherent in the NPC inverter. It is extremely important to keep the upper and lower DC-link capacitor voltages balanced to guarantee the three level operation of ...

    • A novel multilevel carrier-based PWM-control method for GTO inverter in low index modulation region 

      Ben-Brahim, Lazhar; Tadakuma, Susumu ( IEEE , 2006 , Article)
      Gate turn offs (GTOs) have an inherent minimum ON-OFF time, which is needed for their safe operation. For GTO-based three-level or neutral-point-clamped (NPC) inverters, this minimum ON-OFF pulsewidth limitation results ...

    • Research in undergraduate education at Qatar University: EE department experience 

      Hasna , Mazen ( IEEE , 2007 , Conference Paper)
      This paper presents the research efforts taking place at Qatar University, the only national university in Qatar. Being a teaching institute, conducting research faces many challenges. The paper focuses on the experience ...

    • Power loading algorithms for SEC diversity schemes 

      Halwani H.A.; Hasna , Mazen; Alouini M.-S. ( IEEE , 2007 , Conference Paper)
      Switch and Examine Combing (SEC) diversity scheme is one of the simplest diversity schemes to combat fading. When the power used for probing the channels in this scheme is fixed, it can be higher than what is actually ...

    • A novel amplitude-to-phase converter for sine/cosine position transducers 

      Benammar, M. ( Taylor and Francis Group , 2007 , Article)
      Resolvers and various other types of sine/cosine encoders are used for both angular and linear position sensing. These devices provide analogue signals in the form of the sine and the cosine of an angle related to the ...