低压MOCVD设备设计

采用了一种新的设计原理，即以流量计为基准，将气体入口端和出口端压力双重分别统一控制，进行了低压ＭＯＣＶＤ设计。本设备引入模拟反应室，减少了在ＶＥＮＴ－ＲＵＮ转换时反应室内的压力波动，为确保材料生长的生均匀性提供了有利条件。     

高清晰度电视中8—VSB与COFDM传输方案的分析比较

本文简要介绍高清晰度电视中８－ＶＳＢ和ＣＯＦＤＭ传输方案及其基本原理，并针对传信率为１／Ｔ＝２３．５４８Ｍｂｐｓ的８－ＶＳＢ生ＣＯＦＤＭ作了计算机模拟，最后对该两种传输系统作了结构和性能上的比较分析。     

LP—MOCVD生长InGaAlP系统中源气流的动力学研究

分析了ＬＰ－ＭＯＣＶＤ生长ＩｎＧａＡｌＰ外延层时，气路系统中ＩＩＩＡ族源气的输运和扩散过程，从理论止推导出源气流量的计算公式，讨论了生长控制参数、气路管道几何尺寸和源气性质等对注入反应室的源气流量的影响，为精确控制气相中ＩＩＩＡ族源物质的百分含量提供了理论依据。     

CMOS电路芯片ESD保护电路设计技术的发展

本文简要地回顾了ＣＭＯＳ电路芯片上ＥＳＤ保护电路设计技术发展概况，给出了在中小规模、大规模及超大规模各阶段的ＣＭＯＳ电路芯片上ＥＳＤ保护电路的主流技术，双寄生的ＳＣＲ结构ＶＬＳＩ ＣＭＯＳ芯片上ＥＳＤ保护电路的最新设计技术，就其ＥＳＤ保护原理、设计技术及取得的成果做了较详细分析和探讨。对于研制高密度、高速度的ＶＬＳＩ ＣＭＯＳ电路。开展高ＥＳＤ失效阈值电压，小几何尺寸及低ＲＣ延迟时间常数保护电路的     

MOS结构衬底电阻率ρ对阈值电压VT动态调制的计算机模拟

使用ＭＳ－ＰＣ工艺模拟ＣＡＤ系统对绝缘栅Ｐ－ＭＯＳ结构栅氧过程中衬底电阻率ρ与ＭＯＳ结构阈值电压ＶＴ之间的因变关系进行了动态模拟。定量地考查了栅氧层制备过程中杂质的分凝效应对阈值电压ＶＴ的影响。     

COFDM技术在数字TV／HDTV中的应用

介绍ＣＯＦＤＭ技术在ＤＴＶ／ＨＤＴＶ中应用的基本原理，分析克服多径干扰和常规电视干扰措施的性能，并阐述了ＣＯＦＤＭ技术硬件设计中的有关问题。     

一种低压智能功率集成技术

本文介绍了一种以传统多晶硅栅ＶＤＭＯＳ工艺为主的新型自隔离智能功率集成工艺技术。该技术可以将ＶＤＭＯＳ、ＨＶ－ＣＭＯＳ、ＬＶ－ＣＭＯＳ、ｎｐｎ双极晶体管、齐纳二极管、电容等器件集成在同一单片电路中。整个工艺仅１０块掩模版。结合我们研制的高边智能功率开关电路，对器件结构、特性和工艺设计考虑进行了详细的分析。     

有器件非线性时VSB和COFDM系统性能比较

本文对ＶＳＢ和ＣＯＦＤＭ数字传输系统的性能进行了理论分析和模拟，结果证明从线性系统角度考虑，这两种传输系统在性能上是等价的。本文还就这两种系统对器件非线性的要求进行了分析和模拟，其结果说明ＣＯＦＤＭ系统要求器件具有较小的三阶交调和三阶互调分量，并且，ＣＯＦＤＭ系统峰值－平均功率电平比较大，这将导致ＣＯＦＤＭ接收机中Ａ／Ｄ变换器和数字信号处理位数大于１２比特。     

一种新型准静态D─触发器设计

本文将介绍一种新型的ＣＭＯＳ准静态Ｄ─触发器的结构，这种新结构结合了ＮＭＯＳ结构和ＣＭＯＳ结构的优点。在这篇论文中将这种新型结构与ＮＭＯＳ传输门Ｄ─触发器、普通ＣＭＯＳ传输门Ｄ─触发器在结构、功能、集成度和特性等方面进行了比较，讨论这种新结构中ＭＯＳ管尺寸的设计，并且通过电路模拟软件ＳＰＩＣＥ对电路进行特性分析和比较。     

MOCVD生长的Ⅱ－Ⅵ族化合物固溶体组分的热力学分析2．Hg_（1－x）Cd_xTe体系

本文对ＭＯＣＶＤ生长Ｈｇ１－ｘＣｄｘＴｅ进行了热力学分析．所用的起始原材料为Ｈｇ、ＤＭ－Ｃｄ和Ｒ２Ｔｅ．计算结果一方面表明ＣｄＴｅ优先并入倾向使得在通常的ＤＡＧ工艺中ｘ值非常不易控制．另一方面表明即使在Ｈｇ存在的情况下，也可以沉积几乎纯的ＣｄＴｅ，这对实现ＩＭＰ工艺非常有利，计算结果还表明ＩＩ／ＶＩ比对ＨｇＣｄＴｅ的组分控制起着关键性的作用．在ＤＡＧ工艺中，较低的ＩＩ／ＶＩ比可以改善对ｘ值的控制能力，ＬＭＰ－ＤＡＧ工艺是降低ＩＩ／ＶＩ比的较好途径．本文还计算了生长温度和反应室压力对固相组分的影响以及ＬＭＰ     

Effective Capacity-Based Quality of Service Measures for Wireless Networks

An important objective of next-generation wireless networks is to provide quality of service (QoS) guarantees. This requires a simple and efficient wireless channel model that can easily translate into connection-level QoS measures such as data rate, delay and delay-violation probability. To achieve this, in Wu and Negi (IEEE Trans. on Wireless Communications 2(4) (2003) 630–643), we developed a link-layer channel model termed effective capacity, for the setting of a single hop, constant-bit-rate arrivals, fluid traffic, and wireless channels with negligible propagation delay. In this paper, we apply the effective capacity technique to deriving QoS measures for more general situations, namely, (1) networks with multiple wireless links, (2) variable-bit-rate sources, (3) packetized traffic, and (4) wireless channels with non-negligible propagation delay. Dapeng Wu received B.E. in Electrical Engineering from Huazhong University of Science and Technology, Wuhan, China, in 1990, M.E. in Electrical Engineering from Beijing University of Posts and Telecommunications, Beijing, China, in 1997, and Ph.D. in Electrical and Computer Engineering from Carnegie Mellon University, Pittsburgh, PA, in 2003. From July 1997 to December 1999, he conducted graduate research at Polytechnic University, Brooklyn, New York. During the summers of 1998, 1999 and 2000, he conducted research at Fujitsu Laboratories of America, Sunnyvale, California, on architectures and traffic management algorithms in the Internet and wireless networks for multimedia applications. Since August 2003, he has been with Electrical and Computer Engineering Department at University of Florida, Gainesville, FL, as an Assistant Professor. His research interests are in the areas of networking, communications, multimedia, signal processing, and information and network security. He received the IEEE Circuits and Systems for Video Technology (CSVT) Transactions Best Paper Award for Year 2001. Currently, he is an Associate Editor for the IEEE Transactions on Vehicular Technology and Associate Editor for International Journal of Ad Hoc and Ubiquitous Computing. He served as Program Chair for IEEE/ACM First International Workshop on Broadband Wireless Services and Applications (BroadWISE 2004); and as TPC member of over 20 conferences such as IEEE INFOCOM'05, IEEE ICC'05, IEEE WCNC'05, and IEEE Globecom'04. He is Vice Chair of Mobile and wireless multimedia Interest Group (MobIG), Technical Committee on Multimedia Communications, IEEE Communications Society. He is a member of the Award Committee, Technical Committee on Multimedia Communications, IEEE Communications Society. He is also Director of Communications, IEEE Gainesville Section. Rohit Negi received the B.Tech. degree in Electrical Engineering from the Indian Institute of Technology, Bombay, India in 1995. He received the M.S. and Ph.D. degrees from Stanford University, CA, USA, in 1996 and 2000 respectively, both in Electrical Engineering. He has received the President of India Gold medal in 1995. Since 2000, he has been with the Electrical and Computer Engineering department at Carnegie Mellon University, Pittsburgh, PA, USA, where he is an Assistant Professor. His research interests include signal processing, coding for communications systems, information theory, networking, cross-layer optimization and sensor networks.     

Comments on “A Class of Fault-Tolerant Multiprocessor Networks”

A. Ghafoor presented node-disjoint paths of even networks using Figs. 4, 5, 6,and 7 (Ghafoor, IEEE Trans. Reliability, vol. 38, no. 1, pp. 5-15). However, the paper contains errors which cause confusion. We show that the node-disjoint paths, and Theorem 4 (Ghafoor, IEEE Trans. Reliability, vol. 38, no. 1, pp. 5-15), are not correct. We propose advanced node-disjoint paths, and prove that the fault diameter of even networks is d+1. This is optimal.     

X-ray metrology for high-k atomic layer deposited HfxZr1−xO2 films

Hafnium-based dielectrics are the most promising material for SiO₂ replacement in future nodes of CMOS technology. While devices that utilize HfO₂ gate dielectrics suffer from lower carrier mobility and degraded reliability, our group has recently reported improved device characteristics with a modified Hf_xZr_1−xO₂ [R.I. Hegde, D.H. Triyoso, P.J. Tobin, S. Kalpat, M.E. Ramon, H.-H. Tseng, J.K. Schaeffer, E. Luckowski, W.J. Taylor, C.C. Capasso, D.C. Gilmer, M. Moosa, A. Haggag, M. Raymond, D. Roan, J. Nguyen, L.B. La, E. Hebert, R. Cotton, X.-D. Wang, S. Zollner, R. Gregory, D. Werho, R.S. Rai, L. Fonseca, M. Stoker, C. Tracy, B.W. Chan, Y.H. Chiu, B.E. White, Jr., in: Technical Digest - International Electron Devices Meet, vol. 39, 2005, D.H. Triyoso, R.I. Hegde, J.K. Schaeffer, D. Roan, P.J. Tobin, S.B. Samavedam, B.E. White, Jr., R. Gregory, X.-D. Wang, Appl. Phys. Lett. 88 (2006) 222901]. These results have lead to evaluation of X-ray reflectivity (XRR) for monitoring high-k film thickness and control of Zr addition to HfO₂ using measured film density. In addition, a combination of XRR and spectroscopic ellipsometry (SE) is shown to be a fast and non-intrusive method to monitor thickness of interfacial layer between high-k and the Si substrate.     

Characterisation of electroplated Sn/Ag solder bumps

Environmental concerns as well as legal constraints have been pushing research on flip chip technology towards the development of lead-free solders and also to new deposition techniques [Z.S. Karim, R. Schetty, Lead-free bump interconnections for flip-chip applications, in: IEEE/CPMT 1nternational Electronics Manufacturing Technology Symposium, 2000, pp. 274-278, P. Wölflick, K. Feldmann, Lead-free low-cost flip chip process chain: layout, process, reliability, in: IEEE International Electronics Manufacturing Technology (IEMT) Symposium, 2002, pp. 27-34, M. McCormack, S. Jin, The design and properties of new, pb-free solder alloys, in: IEEE/CPMT International Electronics Manufacturing Technology Symposium, 1994, pp. 7-14, T. Laine-Ylijoki, H. Steen, A. Forsten, Development and validation of a lead-free alloy for solder paste applications. IEEE Transactions on Components, Packaging, and Manufacturing technology, 20(3) (1997) 194-198, D. Frear, J. Jang, J. Lin, C. Zhang, Pb-free solders for flip-chip interconnects, JOM, 53(6) (2001) 28-32].Binary and ternary tin alloys are promising candidates to substitute lead-content components. In this paper, we describe an electroplating technique for high density FlipChip packaging [M. Bigas, E. Cabruja, Electrodeposited Sn/Ag for flip chip connection, CDE (2003)]. An analysis using Auger Electron Spectroscopy (AES) together with additional Energy Dispersive Xray analysis (EDS) tests and Scanning Electron Microscope (SEM) analysis have been performed to optimize the reflow process of the electrodeposited bumps.     

Finite-element modeling of soft tissue rolling indentation

We describe a finite-element (FE) model for simulating wheel-rolling tissue deformations using a rolling FE model (RFEM). A wheeled probe performing rolling tissue indentation has proven to be a promising approach for compensating for the loss of haptic and tactile feedback experienced during robotic-assisted minimally invasive surgery (H. Liu, D. P. Noonan, B. J. Challacombe, P. Dasgupta, L. D. Seneviratne, and K. Althoefer, "Rolling mechanical imaging for tissue abnormality localization during minimally invasive surgery, " IEEE Trans. Biomed. Eng., vol. 57, no. 2, pp. 404-414, Feb. 2010; K. Sangpradit, H. Liu, L. Seneviratne, and K. Althoefer, "Tissue identification using inverse finite element analysis of rolling indentation," in Proc. IEEE Int. Conf. Robot. Autom. , Kobe, Japan, 2009, pp. 1250-1255; H. Liu, D. Noonan, K. Althoefer, and L. Seneviratne, "The rolling approach for soft tissue modeling and mechanical imaging during robot-assisted minimally invasive surgery," in Proc. IEEE Int. Conf. Robot. Autom., May 2008, pp. 845-850; H. Liu, P. Puangmali, D. Zbyszewski, O. Elhage, P. Dasgupta, J. S. Dai, L. Seneviratne, and K. Althoefer, "An indentation depth-force sensing wheeled probe for abnormality identification during minimally invasive surgery," Proc. Inst. Mech. Eng., H, vol. 224, no. 6, pp. 751-63, 2010; D. Noonan, H. Liu, Y. Zweiri, K. Althoefer, and L. Seneviratne, "A dual-function wheeled probe for tissue viscoelastic property identification during minimally invasive surgery," in Proc. IEEE Int. Conf. Robot. Autom. , 2008, pp. 2629-2634; H. Liu, J. Li, Q. I. Poon, L. D. Seneviratne, and K. Althoefer, "Miniaturized force indentation-depth sensor for tissue abnormality identification," IEEE Int. Conf. Robot. Autom., May 2010, pp. 3654-3659). A sound understanding of wheel-tissue rolling interaction dynamics will facilitate the evaluation of signals from rolling indentation. In this paper, we model the dynamic interactions between a wheeled probe and a soft tissue sample using the ABAQUS FE software package. The aim of this work is to more precisely locate abnormalities within soft tissue organs using RFEM and hence aid surgeons to improve diagnostic ability. The soft tissue is modeled as a nonlinear hyperelastic material with geometrical nonlinearity. The proposed RFEM was validated on a silicone phantom and a porcine kidney sample. The results show that the proposed method can predict the wheel-tissue interaction forces of rolling indentation with good accuracy and can also accurately identify the location and depth of simulated tumors.     

A Reconfigurable Gaussian/Triangular Basis Functions Computation Circuit

A CMOS Gaussian/Triangular Basis functions computation circuit suitable for analog neural networks is proposed. The circuit can be configured to realize any of the two functions. The circuit can approximate these functions with relative root-mean-square error less than 1%. It is shown that the center, width, and peak amplitude of the dc transfer characteristic can be independently controlled. SPICE simulation results using 0.18 μ m CMOS process model parameters of TSMC18 technology are included. Muhammad Taher Abuelma'Atti was born in Cairo, Egypt, in 1942. He received the B.Sc. degree in Electrical Engineering in 1963 from the University of Cairo, Cairo, Egypt, the Ph.D. degree in 1979 and the Doctor of Science degree in 1999 both from the University of Bradford, Bradford, England. From 1963 to 1967, he worked at the Military Technical College in Cairo as a Teaching Assistant. He was with the Iron and Steel Company in Helwan, Cairo, from 1967 to 1973 as a Senior Electrical Engineer. From 1973 to 1976 he was with the College of Engineering, University of Riyadh, Saudi Arabia, as a Teaching Assistant. From 1980 to 1981, he worked with the Faculty of Engineering, University of Khartoum, Sudan, as an Assistant Professor, and from 1981 to 1982 he was with the College of Engineering, King Saud University, Riyadh, Saudi Arabia, as an Assistant Professor. In 1982 he joined the College of Engineering, University of Bahrain and in 1987 he became an Associate Professor. In 1991 he joined the College of Engineering Sciences, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, where he became a Full Professor in January 1995. Dr. Abuelma'Atti is the recipient of the 1994/1995 Excellence in Teaching Award and the 1995/1996 and 2000/2001 Excellence in Research Award. Both at King Fahd University of Petroleum and Minerals. Dr. Abuelma'Atti is a contributor to Encyclopedia of RF and Microwave Engineering, Kai Chang, Editor, (New York: John Wiley, 2005), Survey of Instrumentation and Measurement, S.A. Dyer, Editor, (New York: John Wiley, 2001), The Encyclopedia of Electrical and Electronic Engineering, J.G. Webster, Editor, (New York:John Wiley, 1999), and Selected Papers on Analog Fiber-Optic Links, E.I. Ackerman, C.H. Cox III and N.A. Riza, Editors, SPIE Milestone Series, (Washington: SPIE Optical Engineering Press, 1998). His research interests include problems related to analysis and design of nonlinear electronic circuits and systems, analog integrated circuits and active networks design. He is the author or co-author of over 500 journal articles and technical presentations. Abdullah Bakri Shwehneh was born in Aleppo Syria, in 1973. He received the B. Sc. degree in electrical engineering in 1998 from Sumy State University, Sumy, Ukraine. In 2001, he received the Postgraduate Diploma in Automatic Control from Aleppo State University, Aleppo, Syria. In 2001, he joined the “Electronic Brain Company for Computer and Electronics” as an Electronic & Computer Engineer and since 2002, he is with King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia, as a Research Assistant. In June 2005 he obtained his Master of Science Degree in Analog Electronics from KFUPM. At present he is a Ph.D. student at KFUPM. His main interests are in Nonlinear circuits, VLSI Analog Design and Neural Networks hardware implementation.     

Performance of Multilayered Video Encoding and Delivery over Lossy Channels Using a Joint Source-Channel Coding Approach

In this paper, the performance of selected error-control schemes based on forward error-control (FEC) coding for H.263+ video transmission over an additive white Gaussian noise (AWGN) channel is studied. Joint source and channel coding (JSCC) techniques that employ single-layer and 2-layer H.263+ coding in conjunction with unequal error protection (UEP) to combat channel errors are quantitatively compared. Results indicate that with appropriate joint source and channel coding, tailored to the respective layers, FEC-based error control in combination with 2-layer video coding techniques can lead to more acceptable quality for wireless video delivery in the presence of channel impairments. Yong Pei is currently a tenure-track assistant professor in the Computer Science and Engineering Department, Wright State University, Dayton, OH. Previously he was a visiting assistant professor in the Electrical and Computer Engineering Department, University of Miami, Coral Gables, FL. He received his B.S. degree in electrical power engineering from Tsinghua University, Beijing, in 1996, and M.S. and Ph.D. degrees in electrical engineering from Rensselaer Polytechnic Institute, Troy, NY, in 1999 and 2002, respectively. His research interests include information theory, wireless communication systems and networks, and image/video compression and communications. He is a member of IEEE and ACM. James W. Modestino (S′67- M′73- SM′81- F′87) was born in Boston, MA, on April 27, 1940. He received the B.S. degree from Northeastern University, Boston, MA, in 1962, and the M.S. degree from the University of Pennsylvania, Philadelphia, PA, in 1964, both in electrical engineering. He also received the M.A. and Ph.D. degrees from Princeton University, Princeton, NJ, in 1968 and 1969, respectively. He has held a number of industrial positions, including positions with RCA Communications Systems Division, Camden, NJ; General Electronic Laboratories, Cambridge, MA; AVCO Systems Division, Wilmington, MA; GTE Laboratories, Waltham, MA; and MIT Lincoln Laboratories, Lexington, MA. From 1970 to 1972, he was an Assistant Professor in the Department of Electrical Engineering, Northeastern University. In 1972, he joined Rensselaer Polytechnic Institute, Troy, NY, where until leaving in 2002 he was an Institute Professor in the Electrical, Computer and Systems Engineering Department and Director of the Center for Image Processing Research. He has been responsible for teaching and research in the communication, information and signal processing systems area. His specific research interests include communication in fading dispersive channels; detection, estimation and filtering in impulsive or burst noise environments; digital signal, image and video processing; and multimedia communication systems and networks. In 2002 he joined the Department of Electrical and Computer Engineering at the University of Miami, Coral Gables, FL, as the Victor E. Clarke Endowed Scholar, Professor and Chair. He has held visiting positions with the University of California at San Diego, LaJolla, CA (1981–1982); GE Research and Development Center, Schenectady, NY (1988–1989); and Massachusetts Institute of Technology, Cambridge, MA (1995–1996). Dr. Modestino is a past member of the Board of Governors of the IEEE Information Theory Group. He is a past Associate Editor and Book Review Editor for the IEEE TRANSACTIONS ON INFORMATION THEORY. In 1984, he was co-recipient of the Stephen O. Rice Prize Paper Award from the IEEE Communications Society and in 2000 he was co-recipient of the best paper award at the International Packet Video Conference.     

Elemental Compositions of Over 80 Cell Phones

Over the last few years, 85 cell phones have been disassembled, ground up, dissolved, and analyzed for elemental content, mainly for information about the metals present in the phones, but also for some metalloids and nonmetals. The following list of 38 elements were detected in some or all of the phones: Be, B, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Y, Nb, Pd, Ag, In, Sn, Sb, Te, Ba, Ta, W, Pt, Au, Tl, Pb, Bi, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Er. Cadmium was never detected. This paper discusses the methods used for carrying out the analysis, proposes possible sources in the telephones for the elements of interest, the reasons for the interest in most of the elements, and method repeatability.     

EHM业务及其对物联网能力的需求

说明了ITU-T Y.2065 EHM参考模型与ITU-T Y.2060物联网参考模型的区别。参考ITU-T Y.2065分析了EHM业务及其3种子类业务,即EHMH、EHMR和EHMT,并对EHM业务对物联网基础设施的能力需求进行了简要说明。     

A State-Space Approach to Multiuser Parameters Estimation Using Central Difference for CDMA Systems

In this paper, it is shown that a state-space model applies to the code-division multiple-access (CDMA) channel, and Central Difference Filter (CDF) produces channel estimates with the minimum mean-square error (MMSE). This result may be used as compare to Extended Kalman Filter (EKF) which used as channel estimator in CDMA system. The main purpose of this paper is to compare robustness of channel estimator for realistic rapidly time-varying Rayleigh fading channels. To overcome the highly nonlinear nature of time delay estimation and also improve the accuracy, consistency and efficiency of channel estimation, an iterative nonlinear filtering algorithm, called the CDF has been applied in the field of CDMA System. The proposed channel estimator has a more near-far resistant property than the conventional Extended Kalman Filter (EKF). Thus, it is believed that the proposed estimator can replace well-known filters, such as the EKF. The Cramer-Rao lower bound (CRLB) is derived for the estimator, and simulation result show that it is nearly near-far resistant and clearly outperforms the EKF. Jang Sub Kim was born June 15, 1974, in Yeongdeok, Korea. He received the M.S. degree in school of electrical and computer engineering from Sungkyunkwan University, Seoul, Korea. He is currently with the School of Information and Communication Engineering, Sungkyunkwan University, where he was a Ph. D. student since 1999. His research interests include code-division multiple access, channel estimation, position location, and wireless communications. Seokho Yoon (S‘99–M‘1) received the B.S.E. (summa cum laude), M.S.E., and Ph.D. degrees in electrical engineering from KAIST, Daejeon, Korea, in 1997, 1999, and 2002, respectively. From April 2002 to June 2002, he was with the Department of Electrical Engineering and Computer Sciences, Massachusetts Institute of Technology, Cambridge, MA, and from July 2002 to February 2003, he was with the Department of Electrical Engineering, Harvard University, Cambridge, MA, as a Postdoctoral Research Fellow. In March 2003, he joined the School of Information and Communication Engineering, Sungkyunkwan University, Suwon, Korea, where he is currently an Assistant Professor. His research interests include spread spectrum systems, mobile communications, detection and estimation theory, and statistical signal processing. Dr. Yoon is a member of the IEEK and KICS. He was the recipient of a Bronze Prize at Samsung Humantech Paper Contest in 2000. Dong-Ryeol Shin (M‘97) was born in Seoul, Korea, in 1957. He received the B.S., M.S. and Ph.D degree in electrical engineering from the Sungkyunkwan University in 1980, and the Korea Advanced Institute of Science and Technology (KAIST) in 1982 and the Georgia Institute of Technology in 1992, respectively. During 1992-1994, he had worked for Samsung Data Systems, Ltd., Korea. Since 1994, he has been with network research group at the Sungkyunkwan University, Korea, as a professor. His current research interests include wireless communications and ubiquitous computing.