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2004 RF and Microwave Conference, RFM 2004

作者： Ng, Chee Kyun Khatun, Sabira Ali, Borhanuddin Mohd Jamuar, Sudhanshu Shekhar Ismail, Mahamod Department of Computer and Communication Systems Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical and Electronic Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical Electronic and System Engineering Faculty of Engineering Universiti Kebangsaan Malaysia Malaysia

ISBN: (纸本)078038671X

Throughout the history of wireless communications, spatially diversity's antenna array system has being important in improving the radio link between wireless users. Moreover, this system are proposed to reduce the multipath fading through its directivity narrowly radiation beam. The introduction of interference free window in delay domain from newly LAS-CDMA standard has received many attentions for furthering research on multipath delay spread. In this paper, we studied the effect of angular spread on maximum excess delay in multipath propagation environments. Then, we examined the application of antenna array in LAS-CDMA standard to overcome this multipath phenomenon. First of all, the multipath propagation literatures are reviewed, followed by the explanation of maximum angular spread in a simple discrete ring of scatterers model. Comparison analyses are made between conventional omnidirectional antenna and narrow beam antenna array. Finally, the analytical performances in term of power delay profile are presented. © 2004 IEEE.

关键词： Code division multiple access

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Photorefractive bi-directional connection module with mutual-pumped phase conjugate mirror

Photorefractive bi-directional connection module with mutual...

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Information Optics and Photonics Technology

作者： Kori, Kazumasa Okamoto, Atsushi Takayama, Yoshihisa Bunsen, Masatoshi Funakoshi, Hisatoshi Ito, Terumasa Research Group of Computer and Communication System Graduate School of Engineering Hokkaido University Wireless Communications Department National Institute of Information and Communications Technology Research Group of Computer and Communication System Graduate School of Engineering Hokkaido University Kita13-Nishi8 Kita-ku Sapporo 060-8628 Japan

The purpose of this study is to apply a free-space optical interconnection to a reconfigurable board-to-board connection where the wiring patterns connecting boards are optically formed without electrical-optical conversion. We regard a photorefractive bi-directional connection module (PBCM) based on a mutually pumped phase conjugate mirror as a key device to construct such a connection network and employ PBCMs at input/output interfaces of each board. Although optical behaviors of PBCM are influenced by the exposure conditions, we especially focus on the diameter of beams illuminating photorefractive media placed inside PBCM so as to find some geometrical restrictions hi a design of networking system. Through numerical analyses, we show a sample configuration of PBCM for the board-to-board interconnection and present a conceptual design of input/output interface.

关键词： Optical interconnects

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Smart antenna system with orthogonal codes

Smart antenna system with orthogonal codes

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Proceedings of the IEEE 6th Circuits and systems Symposium on Emerging Technologies: Frontiers of Mobile and Wireless communication

作者： Ng, Chee Kyun Mohd Ali, Borhanuddin Jamuar, Sudhanshu Shekhar Ismail, Mahamod Department of Computer and Communication Systems Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical and Electronic Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical Electronic and System Engineering Faculty of Engineering Universiti Kebangsaan Malaysia Malaysia

ISBN: (纸本)0780379381

Smart antenna, which improves the performance of wireless systems, suppress all interfering signals, and increase the system capacity. The objective of this paper is to provide an analysis of system capacity when using smart antenna with the orthogonal code. A new technique which use orthogonal codes in multiple beams to distinguish multi-user is introduced. The properties of LinkAir communications' large area synchronous (LAS) or smart codes, which are claimed to be fully orthogonal code and are used to combat major interferences, are studied. The effect of spatial multiple beams in an area where density of users is very condense in a cell is also examined. Finally, the system performance in term of system capacity is presented.

关键词： Mobile telecommunication systems

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Optimization on the preparation of microfluidic channel using dry film resist 1

Optimization on the preparation of microfluidic channel usin...

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1st IEEE International Conference on Smart Sensors and Application, ICSSA 2015

作者： Kamuri, Firdaus Abidin, Zurina Zainal Md Yunus, Nurul Amziah Hamidon, Mohd Nizar Yaacob, Mohd Hanif Kamarudin, Suryani Zhukhi, Siti Zalikha Department of Chemical and Environmental Engineering Universiti Putra Malaysia Selangor Malaysia Department of Electrical and Electronic Engineering Universiti Putra Malaysia Selangor Malaysia Department of Computer and Communication System Engineering Universiti Putra Malaysia Selangor Malaysia

ISBN: (纸本)9781479973644

In this work, microfluidic channel was explored using dry film resist (DFR) method. Many of previous studies used SU-8 and PDMS as the medium to fabricate microfluidic channel for making a microfluidic chamber. Microscope slides were used as the substrate for the applications with bio components since it is inert and stable. The DFR serves to be the spacer to form the channel. Several processes which include cleaning, drying, prebaking, laminating, UV exposure and finally post-baking were involved in channel making. These processes need to be optimized in order to obtain a good chamber. Silicon rubber and UV glue were used to seal the chamber system to prevent any leakages. © 2015 IEEE.

关键词： Film preparation

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Impact of inter-cell interference on capacity in the joint multiple access (CDMA and SDMA) system

Impact of inter-cell interference on capacity in the joint m...

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2005 Asia-Pacific Conference on communications

作者： Ng, Chee Kyun Ismail, Mahamod Ali, Borhanuddin Mohd Khatun, Sabira Jamuar, Sudhanshu Shekhar Department of Computer and Communication Systems Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical and Electronic Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical Electronic and System Engineering Faculty of Engineering Universiti Kebangsaan Malaysia Malaysia

ISBN: (纸本)0780391322

Spatial filtering using smart antenna has emerged as a promising technique to improve the performance of cellular systems. Cell splitting and sectorisation in CDMA systems could result in an increase in system capacity. In this paper, we investigate the impact of inter-cell interference on reverse link capacity in a joint multiple access system arising from the combination of CDMA and SDMA systems. The system capacity of CDMA and SDMA systems is reviewed individually. The co-channel and antenna side-lobes interferences in SDMA systems due to the randomly located mobile users in a non-uniform traffic cell are studied. Therefore, the most realistic reverse link capacity improvement of the joint multiple access system is presented here by taking into consideration both intra-sector and inter-sector interferences. The results are based on the system parameters of CDMA and SDMA systems. © 2005 IEEE.

关键词： Code division multiple access

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Performance of LAS-CDMA system using smart antenna

Performance of LAS-CDMA system using smart antenna

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2005 13th IEEE International Conference on Networks jointly held with the 2005 7th IEEE Malaysia International Conference on communications

作者： Ng, Chee Kyun Mohd Ali, Borhanuddin Khatun, Sabira Jamuar, Sudhanshu Shekhar Ismail, Mahamod Department of Computer and Communication Systems Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical and Electronic Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia Department of Electrical Electronic and System Engineering Faculty of Engineering Universiti Kebangsaan Malaysia Malaysia

ISBN: (纸本)1424400007

The choice of CDMA spreading sequences predetermines the properties of the system. The properties of large area synchronous (LAS) CDMA system have been demonstrated an interference free window (IFW) compared to traditional CDMA systems. This IFW property, however, has a limited delay-offset range. It is not always possible that all the channel-induced multipath delay spread components will arrive within IFW delay-offset range if the conventional antenna is employed. In this paper, the high directive narrow beam of smart antenna system is employed to direct all the multipath propagation components to arrive within the IFW range. Moreover, smart antenna system with its mathematical model is described. The reduction of multipath propagation in smart antenna system is also described. Finally, system performance analysis in terms of BER and maximum delay spread in both conventional and smart antennas are presented. © 2005 IEEE.

关键词： Code division multiple access

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Space Division Duplex (SDD) system using smart antenna

Space Division Duplex (SDD) system using smart antenna

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2005 IEEE International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials, IWAT 2005

The most important property in wireless systems, when it comes to increasing spectral efficiency, is eliminating interference. Recently, there are several new multiple access schemes and duplexing systems have been introduced in wireless systems to overcome several major interferences such as inter symbol interference, multiple access interference and adjacent cell interference. In this paper, we introduce a new duplexing system so-called space division duplex which can eliminate all kinds of interference. This new duplexing system consists of smart antenna's multiple steered narrow beams and orthogonal large area synchronous spread spectrum codes. The purpose is to increase system capacity while maintain its zero correlation window characteristics. The major types of interference and the properties of large area synchronous codes to combat these major interferences are studied. The overviews of code division duplexing system applying these orthogonal smart codes in wireless environment are analyzed. These analyses have shown that the number of orthogonal codes utilization is limited. The proposed solutions of space division duplexing system with several advantages are presented. Besides that, the code reuse concept is proposed to overcome the limitation of orthogonal codes. Finally, the system performances in term of spectral efficiency and capacity are presented. © 2005 IEEE.

关键词： Space division multiple access

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A 657-nm narrow bandwidth interference filter-stabilized diode laser

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Chinese Optics Letters 2011年第4期9卷 46-47页

作者：王正博吕晓凯陈景标 Joint Institute of Metrological Science Department of PhysicsTsinghua University Institute of Quantum Electronics and State Key Laboratory of Advanced Optical Communication System and NetworkSchool of Electronics Engineering and Computer SciencePeking University State Key Laboratory of Precision Spectroscopy East China Normal University

We present a 657-nm external cavity diode laser （ECDL） system, where the output frequency is stabilized by a narrow-band high transmission interference filter. This novel diode laser system emits laser with an insta... 详细信息

关键词： Semiconductor lasers

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Multi-threshold second-order phase transition in laser

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Chinese Science Bulletin 2011年第35期56卷 3812-3816页

作者： ZHUANG Wei YU DeShui LIU ZhiWen CHEN JingBiao Institute of Quantum Electronics and State Key Laboratory of Advanced Optical Communication System ＆ Network School of Electronics Engineering ＆ Computer Science Peking University Beijing 100871 China Department of Electrical Engineering The Pennsylvania State University University Park PA 16802 USA

We present a theory of the multi-threshold second-order phase transition,and experimentally demonstrate the multi-threshold secondorder phase transition *** carefully selected parameters,in an external cavity diode laser system,we observe secondorder phase transition with multiple(three or four) thresholds in the measured power-current-temperature three dimensional phase *** controlled death and revival of second-order phase transition sheds new insight into the nature of ubiquitous secondorder phase *** theory and experiment show that the single threshold second-order phase transition is only a special case of the more general multi-threshold second-order phase transition,which is an even richer phenomenon.

关键词：二阶相变多阈值激光相变激光器系统二极管实验外腔

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Correlation Between Multiple Sclerosis Lesion Areas in Brain Magnetic Resonance Imaging and Patient’s Disability 1

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11th International Conference on Robotics, Vision, Signal Processing and Power Applications, RoViSP 2021

作者： Muslim, Ali M. Mashohor, Syamsiah Mahmud, Rozi Al Gawwam, Gheyath Hanafi, Marsyita Department of Computer and Communication System Engineering Universiti Putra Malasia Serdang Malaysia Department of Imaging Universiti Putra Malaysia Serdang Malaysia Department of Neurology Baghdad University Baghdad Iraq

ISBN: (数字)9789811681295

ISBN: (纸本)9789811681288

Magnetic Resonance Imaging (MRI) plays a very important rule to evaluate Multiple Sclerosis (MS) disease at drug treatment, treatment phase and patient’s follow-up. Identification and characterization of MRI features that are related to MS patient’s disability could be beneficial for efficient treatments, better patient follow-up and avoiding long procedures of physical examination to score MS patient’s disability using Expanded Disability Status Scale (EDSS). This study aims to investigate the correlation between segmented MS-lesion areas in brain MRI and patient’s disability score. Features from manually MS-lesion segmentation done by expert and features from automated MS-lesion segmentation were investigated. Brain extraction, smoothing, threshold-based classifier and SVM have been used for automated MS-lesion segmentation. The automated segmentation produced a Dices Similarity Coefficient (DSC) of 0.5 and high false-positive rate, which indicates the seen and unseen lesions are exist. From the observation, features from automated MS-lesion segmentation have been successfully classified MS patients into two groups at 3.5 EDSS with 100% accuracy using threshold-based classifiers while features from manual lesion segmentation were failed to split MS patients into any group. In conclusion, segmented MS-lesion areas that were obtained by an automated method that only produced DSC of 0.5 with seen lesion correlate with MS patient’s disability, while seen lesion area segmented by manual was not correlated. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Magnetic resonance imaging

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