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.     

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.     

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.     

Bioinspired Self-healing Soft Electronics

Inspired by nature, various self-healing materials that can recover their physical properties after external damage have been developed. Recently, self-healing materials have been widely used in electronic devices for improving durability and protecting the devices from failure during operation. Moreover, self-healing materials can integrate many other intriguing properties of biological systems, such as stretchability, mechanical toughness, adhesion, and structural coloration, providing additional fascinating experiences. All of these inspirations have attracted extensive research on bioinspired self-healing soft electronics. This review presents a detailed discussion on bioinspired self-healing soft electronics. Firstly, two main healing mechanisms are introduced. Then, four categories of self-healing materials in soft electronics, including insulators, semiconductors, electronic conductors, and ionic conductors, are reviewed, and their functions, working principles, and applications are summarized. Finally, human-inspired self-healing materials and animal-inspired self-healing materials as well as their applications, such as organic field-effect transistors (OFETs), pressure sensors, strain sensors, chemical sensors, triboelectric nanogenerators (TENGs), and soft actuators, are introduced. This cutting-edge and promising field is believed to stimulate more excellent cross-discipline works in material science, flexible electronics, and novel sensors, accelerating the development of applications in human motion monitoring, environmental sensing, information transmission, etc.     

Optimization of lithographic masks using genetic algorithms

Due to its cost effectiveness and reliability, wet-chemical etching of silicon is still one of the key technologies for producing bulk-silicon microstructures. In this paper we present an approach for the design of advanced mask sets for anisotropic, wet-chemical etching of silicon. The optimization method of genetic algorithms is used to derive suitable masks for cases where geometrically calculated compensation structures fail. The underlying etch simulation is described as well as the optimization algorithm itself. Design tasks of current research projects are used as examples to illustrate the advantage of using the presented tool. Udo Triltsch was born in Bergisch Gladbach, Germany, in 1976. He received the Dipl.-Ing. degree for Mechanical Engineering from the Technical University of Braunschweig, Germany, in 2002. He is currently working towards his Ph.D. at the Institute for Microtechnology, Braunschweig, Germany. His research interests include: design methodology for MEMS, process simulation and knowledge management. Anurak Phataralaoha was born in Bangkok, Thailand, in 1973. He received the B. Eng. degree for Production Engineering from KMUTT, Thailand in 1995 and Dipl.-Ing. degree for Mechanical Engineering from Technical University of Clausthal, Germany in 2002. He is currently working towards his Ph.D. at the Institute for Microtechnology, Braunschweig, Germany. His research interests include: 3D-tactile sensors, micro machining for silicon, Tribological micro guide. Stephanus Büttgenbach obtained the Diploma and Ph.D. degrees in physics from the University of Bonn, Germany, in 1970 and 1973, respectively. From 1974 to 1985, he was with the Institute of Applied Physics of the University of Bonn, working on atomic and laser spectroscopy. In 1983, he was promoted to Professor of Physics. From 1977 to 1985, he was also a Scientific Associate at CERN in Geneva, Switzerland. In 1985, Dr. Büttgenbach joined the Hahn-Schickard-Society of Applied Research at Stuttgart as Head of the Department of Microtechnology, where he worked on micromechanics, laser microfabrication, and resonant sensors. From 1988 to 1991, he was the Founding Director of the Institute of Micro and Information Technology of the Hahn-Schickard-Society. In 1991, Dr. Büttgenbach became Professor of Microtechnology at the Technical University of Braunschweig. His current research centers on the development and application of micro sensors, micro actuators, and micro systems. Currently, he is Vice President of the Technical University of Braunschweig, where his areas of responsibility are research and technology transfer. Dima Straube was born in Berlin, Germany, in 1977. He received the Dipl.-Ing. degree for Civil Engineering from Technical University of Berlin, Germany, in 2002. He is currently working towards his Ph.D. at the Institute for Engineering Design, Braunschweig. His research interests include: design methodology for MEMS, computer aided design and tolerance management. Hans-Joachim Franke was born in Helmstedt, Germany, on February 14, 1944. He received his diploma in mechanical engineering (Dipl.-Ing.) from the Technical University of Braunschweig, Germany, in 1969. From 1969 to 1976 he was research assistant of Prof. Roth at the Institute for Engineering Design. In 1976 he received his Ph.D. degree in mechanical engineering. From 1976 to 1988 he had diverse executive positions at the KSB-AG in Frankenthal, Germany, a company, which produces pumps and valves. Since 1988 he has been the director of the Institute for Engineering Design of the Technical University of Braunschweig. His research interests are in the areas of design methodology, computer aided design and machine elements.     

Purification of CdTe from,tellurium-rich solutions

Cadmium telluride was grown from tellurium-rich solutions from 600 ‡C to 900 ‡C. Significant purification occurred during growth. Impurities were intentionally-incorporated into the starting materials and the segregation coefficients were measured. Values at 880 ‡C were Hg - 0.3, Zn - 4, S - 4, Se - 2, O ≈0.02, In - 0.06, Al ≈ 0.1, B <1, Tl <0.01, Co - 0.03, Au - 0.1, Ag - 0. 009, Li - 0. 3, Na ≈0.01, K ≈0. 01, Cl ≈0.005, I <0. 5, Pb < 0.005, C ≈0. 5, N ≈0.4, Bi < 0.001, Mg - 1.5, Pt < 0.01, Cr < 1. Supported in part by the AEC, Division of Applied Technology, and ARPA.     

Analysis and VLSI Realization of a Blind Beamforming Algorithm

We present the fixed-point analysis and VLSI realization of a maximum-power blind beamforming algorithm. This algorithm consists of the computation of a correlation matrix and its dominant eigenvector, and we propose that the latter be accomplished by the power method. After analyzing the numerical stability of the power method, we derive a division-free form of the algorithm. Based on a block-Toeplitz assumption, we design an FIR filter based system to realize both the correlation computation and the power method. Our ring processor, which is optimized to implement digital filters, is used as the core of the architecture. A special technique for dynamically switching filter inputs is shown to double the system throughput. VLSI design is discussed in detail and chip fabrication results are presented.Fan Xu received the B.S. and M.S. degrees in electronics engineering from Tsinghua University, Beijing, China, in 1993 and 1996, respectively, and the Ph.D. degree in electrical engineering from the University of California, Los Angeles, in 2001. His Ph.D. research focused on algorithm design and analysis for digital signal processors and eigenvector estimation architectures.In 1997, he held an internship at Bell Labs, Lucent Technologies, Holmdel, NJ, where he worked on equalization algorithms for cellular systems. He joined Broadcom Co., Irvine, CA, in 2001. His research interests include VLSI signal processing, customized digital signal processor, efficient hardware architectures for adaptive signal processing and high-performance VLSI design.Guichang Zhong received the B.S. degree from Xi an Jiaotong University, China, in 1996 and the M.S. degree from the Institute of Microelectronics of Chinese Academy of Sciences, Beijing, China, in 2000, both in electrical engineering. He is currently working toward the Ph.D. degree in integrated circuits and systems at the University of California, Los Angeles.His present research interests are in high-performance VLSI digital signal processors design, with an emphasis on reconfigurable and energy-efficient architecture.Alan N. Willson, Jr. received the B.E.E. degree from the Georgia Institute of Technology, Atlanta, in 1961, and the M.S. and Ph.D. degrees from Syracuse University, Syracuse, NY, in 1965 and 1967 respectively.From 1961 to 1964 he was with IBM, Poughkeepsie, NY. He was an Instructor in electrical engineering at Syracuse University from 1965 to 1967. From 1967 to 1973 he was a Member of the Technical Staff at Bell Laboratories, Murray Hill, NJ. Since 1973, he has been on the faculty of the University of California, Los Angeles (UCLA), where he is Professor of Engineering and Applied Science in the Electrical Engineering Department. In addition, he served the UCLA School of Engineering and Applied Science as Assistant Dean for Graduate Studies from 1977 through 1981 and as Associate Dean of Engineering from 1987 through 2001. He has been engaged in research concerning computer-aided circuit analysis and design, the stability of distributed circuits, properties of nonlinear networks, theory of active circuits, digital signal processing, analog circuit fault diagnosis, and integrated circuits for signal processing. He is editor of Nonlinear Networks: Theory and Analysis (New York: IEEE Press, 1974). In 1991 he founded Pentomics, Inc.Dr. Willson is a member of Eta Kappa Nu, Sigma Xi, Tau Beta Pi, the Society for Industrial and Applied Mathematics, and the American Society for Engineering Education. From 1977 to 1979, he served as Editor of the IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS. In 1980, he was General Chairman of the 14th Asilomar Conference on Circuits, Systems, and Computers. During 1984, he served as President of the IEEE Circuits and Systems Society. He was the recipient of the 1978 and 1994 Guillemin-Cauer Awards of the IEEE Circuits and Systems Society, the 1982 GeorgeWestinghouse Award of the American Society for Engineering Education, the 1982 Distinguished Faculty Award of the UCLA Engineering Alumni Association, the 1984 Myril B. Reed Best Paper Award of the Midwest Symposium on Circuits and Systems, the 1985 and 1994 W.R.G. Baker Awards of the IEEE, the 2000 Technical Achievement Award and the 2003 Mac Van Valkenburg Award of the IEEE Circuits and Systems Society.     

Analog Circuit Synthesis Using Linear and Nonlinear Current Amplifiers

Various design techniques are presented for obtaining current-mode filters suitable for operation at high frequencies. For this purpose CMOS and or bipolar current amplifiers are used as active building blocks. The derived circuits simulate LC passive prototype filters. Second order resonators can also be obtained by following the same techniques. The presented circuits are modular in structure, thus, their electronic and layout design is very easy. Low-voltage, low-power design is also feasible. Simulation examples for all-pole filters and filters with transmission zeros are given. George Souliotis received the B.Sc. degree in physics from the University of Ioannina, Ioannina, Greece, in 1993 and the M.Sc. and Ph.D. degrees in electronics from the University of Patras, Patras, Greece, in 1998 and 2003, respectively. From 2000 to 2002, he was with Giga Hellas, an Intel company, designing high-speed electronic circuits for transceivers for optical networks. He is co-inventor of a patent that was developed through that work. He is currently a Post-Doctoral Researcher with the Electronics Laboratory, Department of Physics, University of Patras, Patras, Greece. His research interests include analog and mixed signal integrated circuits for high-speed communication applications, current mode circuits, continuous time active filters and CMOS-BiCMOS VLSI design. Nikos Fragoulis was born in Megara Attikis, Greece, in 1972. He received the B.S. degree in physics and the M.Sc. degree in electronics and Ph.D. in electronics from the Electronics Laboratory, Department of Physics, University of Patras, Patras, Greece, in 1995, 1998 and 2005 respectively. He is currently a post-doctoral researcher with the Electronics Laboratory, Department of Physics, University of Patras, Patras Greece. His research interests include, continuous time filtering, and analog integrated circuits for broadband telecommunication applications. Ioannis Haritantis received the Ph.D. in Electronics, in 1976, from the Physics Department, University of Patras, Patras, Greece, in collaboration with the Electrical Engineering Department, Imperial College, London, UK. For many years he has conducted scientific research on the development and design of circuits, discrete component and/or integrated, which are suitable for analog signal processing. His other fields of interest include, network theory, design and testing of integrated circuits, integrated active devices for telecommunications and medical instrumentation, smart sensors, and e-learning. During the past few years his focus is on the design of low-power, low-voltage, tunable, integrated active filters of high dynamic range that could operate at high frequencies. Professor Haritantis in now the director of the Electronics Laboratory, Division of Electronics and Computers, Department of Physics, University of Patras, Patras, Greece. He is also in the editorial board of the journal “Analog Integrated Circuits and Signal Processing”, Kluwer Academic Publishers.     

UHF RF Front-End Circuits in 0.35-μm Silicon on Insulator (SOI) CMOS

In this work, design and measurement results of UHF RF frontend circuits to be used in low-IF and subsampling receiver architectures are presented. We report on three low noise amplifiers (LNA) (i) single-ended (ii) differential (iii) high-gain differential and a double-balanced mixer all implemented in 0.35-μ m SOI (Silicon on Insulator) CMOS technology of Honeywell. These circuits are considered as candidate low-power building blocks to be used in the two fully-integrated receiver chips targeted for deep space communications. Characteristics of square spiral inductors with high quality (Q) factors (as high as 10.8) in SOI CMOS are reported. Single-ended and fully-differential LNA's provide gains of 17.5 dB and 18.74 dB at 435 MHz, respectively. Noise figure of the single-ended LNA is 2.91 dB while the differential LNA's noise figure is 3.25 dB. These results were obtained for the power dissipations of 12.5 mW and 16.5 mW from a 2.5-V supply for the single-ended and differential LNA's, respectively. High-gain low-power differential LNA provides a small-signal gain of 45.6 dB with a noise figure of 2.4 dB at 435 MHz. Total power dissipation of the high gain LNA is 28 mW from a 3.3-V supply. The double-balanced mixer provides a conversion gain of 5.5 dB with a noise figure of 13 dB at 2 MHz IF. The power dissipation of the mixer is 11.5 mW from a 2.5-V supply. The measured responses and the power dissipations of the building blocks meet the requirements of the communications system. The die areas occupied by the single-ended LNA, differential LNA, high-gain LNA and the mixer are 0.6 mm × 1.4 mm, 1 mm × 1.4 mm, 1.4 mm × 1.2 mm and 0.6 mm × 0.9 mm, respectively. Ertan Zencir received the B.Sc. and M.S. degrees in electrical and electronics engineering from Middle East Technical University, Ankara, Turkey, and Ph.D. degree in electrical engineering from Syracuse University, Syracuse, NY in 1995, 1997, and 2003, respectively. He joined the Electrical Engineering and Computer Science Department of University of Wisconsin-Milwaukee as an Assistant Professor in August 2004. 2003). His current research focuses on RFIC and transceiver design for wireless communications. Douglas Te-Hsin Huang was born in Chia-yi Taiwan. He received the B.S. degree in electrical engineering from National Taiwan Ocean University, Kee-lung, Taiwan in 1993, and the M.S. and Ph.D. degrees in electrical engineering from Syracuse University, Syracuse, New York, in 2001 and 2003, respectively. In 2004, he joined Skyworks Solutions Inc., where he is currently an RFIC Design Engineer. His research deals mainly with low-power, infrastructure, analog RFIC, and microwave integrated circuit designs. Besides microwave and semiconductor engineering, Dr. Huang has broad interest in art, music, and philosophy. Ahmet Tekin received his B.S. degree in Electrical Engineering from Bogazici University, Istanbul, Turkey in 2002 and MS degree in Electrical engineering form North Carolina A&T State University, Greensboro, NC. He is currently working towards his PhD degree at University of California, Santa Cruz, CA. He was a Research Assistant at RF Microelectronic Laboratory, North Carolina A&T State University, from 2002 to 2004. He worked on the design of low power UHF transceiver circuits for space applications. He is currently a Research Assistant at Bio-mimetic Microelectronic Systems Laboratory, University of California at Santa Cruz, working on implantable very low power UHF frequency transceiver for a body sensor network. Numan S. Dogan received the B.Sc. degree from Karadeniz Technical University, Trabzon, Turkey, in 1975, the M.Sc. degree from Polytechnic University, New York, in 1979, and the PhD degree from the University of Michigan, Ann Arbor, in 1986, all in electrical engineering. Since 1998, he has been with the Electrical and Computer Engineering Department, North Carolina A&T State University, Greensboro, North Carolina, where he is an Associate Professor. He was a Visiting Faculty Researcher at Air Force Research Laboratory (AFRL), Eglin Air Force Base, Florida, in 1998, and General Electric Corporate Research and Development Laboratory, Schenectady, New York, in 1999. His earlier research interests included microwave and millimeter-wave solid-state devices and circuits, high-temperature electronics, and silicon micromachining. His recent research interests include RF CMOS Integrated Circuits and low-power Medical Implant Communication Systems (MICS) transceivers. Currently he serves as the Chair of the IEEE Central North Carolina Section. In April 2004, he organized “a walking robot competition” for High School Students. He enjoys hiking to Alpine Lakes in the Pacific Northwest and fishing. Ercument Arvas (M'85–SM'89) received the B.S. and M.S. degrees from METU, Ankara, Turkey, in 1976 and 1979, respectively, and the Ph.D. degree from Syracuse University, Syracuse, New York, in 1983, all in Electrical Engineering. Between 1984 and fall of 1987, he was with the Electrical Engineering Department of Rochester Institute of Technology, Rochester, New York. He joined the Electrical Engineering and Computer Science Department of Syracuse University in 1987, where he is currently a Professor. His research interests include numerical electromagnetics, antennas, and microwave circuits and devices.     

Can blockchain link the future?

Recently, decentralization has been extensively explored by researchers. Blockchain, as a representation of decentralized technology, has attracted attention with its unique characteristics, such as irrevocability and security. Consequently, herein, we introduce cutting-edge blockchain technologies from four directions: blockchain system, consensus algorithms, smart contract, and scalability. Subsequently, we analyze the current lack of consensus mechanism, fault tolerance, and block capacity of the blockchain, and the integration of blockchain into 5G/6G mobile communication. Furthermore, we discuss the possible applications of blockchain in intellectual property protection, the Internet of Things, digital twins, standardization, and epidemic prevention and control. Finally, explore the impacts and solutions of blockchain on human society beyond technology.     

Modeling effective properties of chiral composites

After a brief overview of the concepts of electromagnetic chirality and wave propagation in chiral media, this paper deals with the field of microwave-chiral-material modeling. First, studies regarding the scattering of single-chiral or non-chiral elements with different shapes (various designs of helices, Ω-shaped scatterers, wires, and loops) are presented. Results of the backscattered field given by different computer codes are compared. Comparisons among analytical, numerical, and experimental results are also reported. Second, the case of a collection of chiral inclusions is treated. A review of different methods, developed to estimate average properties of helix-loaded materials, is given. Modeling of the effective properties of a chiral slab, such as the rotation angle, ellipticity, permittivity, and permeability, is explored. Reflection and transmission coefficients, evaluated by various methods, are compared with each other, and with measurements. Limitations of the models, possible improvements, and new directions for research are also described. Finally, applications of such composites to the design of radar-absorbing materials are addressed     

基于多网络的矿井智能化监管系统设计

提出一种矿井智能化监管系统设计方案,该系统包括无线传感器网络（WSN）、工业以太网络、人员定位卡、井下视频手机、监管服务器、监控计算机、数据库、中心交换机、智能化监管信息平台。系统将工业以太网络和无线传感器网络结合,构建井下有线／无线的混合通信系统进行数据传输,井上利用智能化信息监管平台实现与井下作业人员、井上管理人员、井上其他人员的数据通信和资源共享;该系统具有井下人员实时定位、井下与井上实时视频通信、矿井环境监测、智能化信息处理、矿井信息分发、资源调度、异常情况报警等功能,矿井环境监测包括对瓦斯、CO、电化学氧气、硫化氢、风速、矿压、温湿度、矿尘、噪音等环境参数的监测。     

A Fault-Tolerant Scheme for Mobility Management in PCS Networks

One of the most important and challenging issues in the design of personal communication service (PCS) systems is the management of location information. In this paper, we propose a new fault-tolerant location management scheme, which is based on the cellular quorum system. Due to quorum's salient set property, our scheme can tolerate the failures of one or more location server(s) without adding or changing the hardware of the systems in the two-tier networks. Meanwhile, with a region-based approach, our scheme stores/retrieves the MH location information in the location servers of a quorum set of the local region as much as possible to avoid long delays caused by the possible long-distance of VLR and HLR. Thus, it yields better connection establishment and update delay. Ming-Jeng Yang received the M.S. degree in computer science from the Syracuse University, New York, in 1991, and the Ph.D. degree in computer science from National Taiwan Normal University, Taiwan, in 2004. He is an associate professor in the Department of Information Technology, Takming College, Taiwan. His research interests include wireless networks, mobile computing, fault-tolerant computing, and distributed computing. He is a member of the IEEE Computer Society and the ACM. Yao-Ming Yeh received the B.S. degree in computer engineering from National Chiao-Tung University, Taiwan, in 1981, and the M.S. degree in computer science and information engineering from National Taiwan University, Taiwan, in 1983. In August 1991, he received the Ph.D. degree in the Department of Electrical and Computer Engineering, The Pennsylvania State University, Pa., U.S.A. He is a professor in the Department of Information and Computer Education, National Taiwan Normal University, Taiwan. His research interests include fault-tolerant computing, web and XML computing, and distributed computing.     

An ultra-wideband log-periodic vibrator of the mirror antenna

The paper is devoted to investigation of ultra-wideband logarithmically periodic vibrators of mirror antennas. The vibrators have the form of cophasal antenna arrays consisting of two log-periodic dipole radiators, comprising a pyramid arranged in the H-plane. The asymmetric and symmetric types of excitation of these dipoles are considered, with their calculated and measured characteristics included. Original Russian Text ? F. F. Dubrovka, N. N. Litvin, S. Ye. Martynyuk, M. N. Bilanovskii, G. A. Yena, 2007, published in Izvestiya VUZ. Radioelektronika, 2007, Vol. 50, No. 4, pp. 26–30.