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Science and Technology Studies Commons

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2008

Performance

Articles 1 - 5 of 5

Full-Text Articles in Science and Technology Studies

Performance Analysis Of Multi-Ary Systems With Iterative Linear Minimum-Mean-Square-Error Detection, Li Ping, Jun Tong, Xiaojun Yuan, Qinghua Guo Jan 2008

Performance Analysis Of Multi-Ary Systems With Iterative Linear Minimum-Mean-Square-Error Detection, Li Ping, Jun Tong, Xiaojun Yuan, Qinghua Guo

Faculty of Engineering and Information Sciences - Papers: Part A

This paper is concerned with coded multi-ary systems over linear channels. Based on a semi-analytical evolution technique, the impact of signaling schemes on the performance of low-cost iterative linear minimum-mean-square-error (LMMSE) detection is studied. It is shown that superposition coded modulation (SCM) maximizes the output signal-to-noise ratio (SNR) of LMMSE detectors. Consequently, SCM may potentially outperform other conventional signaling schemes when LMMSE detectors are used. Numerical examples are provided to verify the theoretical analysis. © 2008 IEEE.


Performance Analysis Of Ofdm-Idma Systems With Peak-Power Limitation, Jun Tong, Qinghua Guo, Li Ping Jan 2008

Performance Analysis Of Ofdm-Idma Systems With Peak-Power Limitation, Jun Tong, Qinghua Guo, Li Ping

Faculty of Engineering and Information Sciences - Papers: Part A

This paper is concerned with orthogonal frequency-division multiplexing interleave-division multiple-access (OFDM-IDMA) systems over frequency-selective fading channels. Deliberate clipping is applied to reduce the peak-to-average power ratio (PAPR) of each user's transmitted signal. An iterative multiuser detection (MUD) technique is developed to recover the performance loss due to clipping. A semi-analytical signal-to- noise ratio (SNR) evolution technique is proposed, which can provide quick and accurate prediction of the iterative MUD performance. Numerical results show that the performance of OFDM-IDMA is not sensitive to the frequency selectivity of channels, and OFDM-IDMA is more power-efficient than other alternative multi-carrier transmission techniques. © 2008 ...


Network Structure, Ict Use And Performance Attitudes Of Knowledge Workers, Kon Shing Kenneth Chung, Liaquat Hossain Jan 2008

Network Structure, Ict Use And Performance Attitudes Of Knowledge Workers, Kon Shing Kenneth Chung, Liaquat Hossain

Faculty of Engineering and Information Sciences - Papers: Part A

In this study, we examine the effect of social network structure and information and communication technologies (ICT) use on performance attitudes of knowledge-intensive workers in dispersed occupational communities. We first develop a theoretical framework and use it to develop a valid and reliable survey instrument. Secondly, we apply structural hole measures (constraint and efficiency) for exploring the association with ICT use and attitudes to performance. Empirical results suggest that density of knowledge workers' professional network is positively associated with ICT use whereas network efficiency is negatively correlated with ICT use at both task and communication-structure level. The findings show that ...


Tangential Sphere Bounds On The Ensemble Performance Of Ml Decoded Gallager Codes Via Their Exact Ensemble Distance Spectrum, Sheng Tong Jan 2008

Tangential Sphere Bounds On The Ensemble Performance Of Ml Decoded Gallager Codes Via Their Exact Ensemble Distance Spectrum, Sheng Tong

Faculty of Engineering and Information Sciences - Papers: Part A

An efficient numerical approach to the exact ensemble distance spectrum of Gallager codes has been developed by evaluating powers of polynomials. With the exact ensemble distance spectrum of Gallager codes, tangential sphere upper bounds on their maximum likelihood (ML) decoding performance over binary input AWGN channels are investigated. Numerical results indicate improved bounds have been obtained, better than Sason and Shamai's results (which are based on Gallager's upper bound on the ensemble distance spectrum), especially in the error floor region. Furthermore, some critical properties of Gallager codes, including typical minimum distance and the performance tradeoff in the waterfall ...


Study Of The Energy Performance Of Korean Apartment Buildings With Alternative Balcony Configurations, Jo Clarke, Cameron Johnstone, Jaemin Kim, Georgios Kokogiannakis, Paul Strachan, Kyung-Hun Woo, Boo-Sik Kang Jan 2008

Study Of The Energy Performance Of Korean Apartment Buildings With Alternative Balcony Configurations, Jo Clarke, Cameron Johnstone, Jaemin Kim, Georgios Kokogiannakis, Paul Strachan, Kyung-Hun Woo, Boo-Sik Kang

Faculty of Engineering and Information Sciences - Papers: Part A

The purpose of this study is to evaluate the impact of the new regulations design changes on heating loads of apartment buildings and identify the construction configurations (e.g. glazing types, thermal properties, window area ratio, etc.) of the new designs that will ensure the energy performance is at least on the same level as those with a traditional balcony configuration.