A system for supporting group activities with a sensor-embedded board

This correspondence describes a system called ePro for supporting face-to-face group activities. ePro connects a sensor-embedded board that utilizes radio frequency identification (RFID) technology for object recognition and a computer simulation, and is currently used to discuss urban planning and environmental problems. Users collaboratively construct a town by placing pieces such as houses on the board. The computer simulation program automatically recognizes the arrangement of pieces on the board. It then shows environmental changes of the town through visualized simulation results. The goal of ePro is to initiate group discussions: The physical board supports the participation of each user by allowing them to manipulate physical objects, and the computer simulation gives users feedback on their manipulation, which triggers their further actions. A comparative user study of ePro (with and without the sensor-embedded board) was conducted. Through the study, ePro has proved its high usability and effectiveness in activating discussions in face-to-face group activities.     

开放式环境下支持协作设计的并发控制机制的研究

针对现有的分布式并发控制机制存在的缺陷,提出一种适合开放式环境下协作设计事务的并发控制机制。该机制将只读事务和更新事务区分开来,只读事务在执行时遵守多版本时间戳排序协议,而更新事务的执行将按基于两阶段有序相容性封锁的多粒度封锁协议进行。这样不仅使用户可以快速得到查询结果,而且有效提高了协作设计事务的并发度。实验分析表明,该机制比较适合于开放式的协同设计环境。     

用于HCN激光器耦合输出的F-P腔的优化设计

本文介绍一种由双面金属栅网构成的F-P腔式激光耦合输出端,改变其间距,透过率可连续变化。将栅网等效为一导纳,利用等效电路方法,进行模拟计算。经优化计算得到一组最佳栅网参数。     

Optimizing sensor networks in the energy-latency-density design space

In wireless sensor networks, energy efficiency is crucial to achieving satisfactory network lifetime. To reduce the energy consumption significantly, a node should turn off its radio most of the time, except when it has to participate in data forwarding. We propose a new technique, called sparse topology and energy management (STEM), which efficiently wakes up nodes from a deep sleep state without the need for an ultra low-power radio. The designer can trade the energy efficiency of this sleep state for the latency associated with waking up the node. In addition, we integrate STEM with approaches that also leverage excess network density. We show that our hybrid wakeup scheme results in energy savings of over two orders of magnitude compared to sensor networks without topology management. Furthermore, the network designer is offered full flexibility in exploiting the energy-latency-density design space by selecting the appropriate parameter settings of our protocol.     

Platform-based mixed signal design: Optimizing a high-performance pipelined ADC

We apply Platform-Based Design (PBD) to the power optimization of a 14 bit, 80 MS/s pipelined Analog-to-Digital Converter (ADC) in a mixed signal formulation. A platform is a library of components and interconnects, each characterized with a set of behavioral, performance and composition models, that is used to raise the level of abstraction to enable system-level design. PBD is a meet-in-the-middle methodology that consists of two phases. The bottom-up phase generates a set of platform libraries that are exploited in the system hierarchy. The top-down phase allows exploring feasible solutions within the platform libraries and selecting the optimum implementation. To evaluate the cost of each implementation, the behavioral models available through platform abstraction are used both for digital and analog components. We provide an example of the use of the methodology and its features for analog circuits by modeling two amplifiers with different topologies as analog components, showing details of the analog characterization process. Then, we create a mixed signal platform library as a combination of an analog and a digital platform (bottom-up phase). The top-down phase performs optimization across the analog/digital boundary to minimize power consumption constrained to given noise and linearity requirements. Simulation results show that interesting power saving can be achieved, as much as 64% compared with an original hand-optimized ADC. Pierluigi Nuzzo received the Laurea degree in electrical engineering from the University of Pisa, Italy, in 2003, and the Diploma from the Scuola Superiore Sant’Anna, Pisa, in 2004, both with honors. Since 2004, he has been with the Department of Information Engineering, University of Pisa, where he is currently working toward the Ph.D. degree in electrical engineering and computer science. During summer 2002 he was with the Fermi National Accelerator Laboratory, Batavia, IL as a student intern working on ASIC testing. From August 2004 to February 2005 he was with IMEC, Leuven, Belgium, as a visiting scholar, working on low power A/D converter design for ultra-wide band applications. His research interests include high speed, low power analog and mixed-signal circuits in CMOS technology, digital calibration of ADCs, system level mixed-signal design and design methodologies. Mr. Nuzzo received first place in the operational category and best overall submission in the 2006 DAC/ISSCC student design competition. Fernando De Bernardinis received the Laurea degree in Electrical Engineering from the University of Pisa, Italy, in 1996 and the M.S. degree and Ph.D. degree from the University of California at Berkeley in 2001 and 2005, respectively. Between 1992 and 1996 he was at the Scuola Superiore S. Anna in Pisa. From 1997 to 1998 he collaborated with the PARADES research center in Rome. During the summers 1999 and 2000 he was at the ST Berkeley labs, working on wireless embedded system design. From 2000 to 2006 he was assistant professor at the Department of Information Engineering at the University of Pisa, Italy. His research interests include mixed-signal design, analog CAD, system level analog design and design methodologies. In 2006 he has joined Marvell Semiconductors, Pavia, Italy, where he works on mixed-signal and RF system design. Alberto Sangiovanni Vincentelli holds the Edgar L. and Harold H. Buttner Chair of Electrical Engineering and Computer Sciences at the University of California at Berkeley. He has been on the Faculty since 1976. He obtained an electrical engineering and computer science degree (“Dottore in Ingegneria”) summa cum laude from the Politecnico di Milano, Milano, Italy in 1971. In 1980–1981, he spent a year as a Visiting Scientist at the Mathematical Sciences Department of the IBM T.J. Watson Research Center. In 1987, he was Visiting Professor at MIT. He has held a number of visiting professor positions at Italian Universities, including Politecnico di Torino, Universita’ di Roma La Sapienza, Universita’ di Roma Tor Vergata, Universita’ di Pavia, Universita’ di Pisa, Scuola Sant’Anna. He was a co-founder of Cadence and Synopsys, the two leading companies in the area of Electronic Design Automation. He is the Chief Technology Adviser of Cadence. He is a member of the Board of Directors of Cadence and the Chair of the Technology Committee, UPEK, a company he helped spinning off from ST Microelectronics, where he is the Chair of its Nominating and Governance Committee and a member of the Audit Committee, Sonics, where he serves as the Chair of the Nominating and Governance Committee, Gradient, where he is a member of the Compensation committee, Accent, an ST Microelectronics-Cadence joint venture he helped founding, and Value Partners. He is the Technology Advisor to the President of the Abruzzo Region. He is a member of the HP Strategic Technology Advisory Board, of the Science and Technology Advisory Board of General Motors and of the Scientific Council of the Tronchetti Provera foundation. He consulted for many companies including Bell Labs, IBM, Intel, United Technology, COMAU, Magneti Marelli, Pirelli, BMW, Daimler-Chrysler, Fujitsu, Kawasaki Steel, Sony, ST and Hitachi. He was an advisor to the Singapore Government for microelectronics and new ventures. He has consulted as Technology Partner for Greylock Ventures and for Vertex Investment. He served as witness in US Congressional investigations on competitiveness of the US economy. He is the founder and Scientific Director of the Project on Advanced Research on Architectures and Design of Electronic Systems (PARADES), a European Group of Economic Interest supported by Cadence, Magneti-Marelli and ST Microelectronics. He is a member of the Advisory Board of the Lester Center for Innovation of the Haas School of Business and of the Center for Western European Studies and a member of the Berkeley Roundtable of the International Economy (BRIE). He is a member of the High-Level Group and of the Steering Committee of the EU Artemis Technology Platform. In 1981, he received the Distinguished Teaching Award of the University of California. He received the worldwide 1995 Graduate Teaching Award of the IEEE (a Technical Field award for “inspirational teaching of graduate students”). In 2002, he was the recipient of the Aristotle Award of the Semiconductor Research Corporation. He has received numerous research awards including the Guillemin-Cauer Award (1982–1983), the Darlington Award (1987–1988) of the IEEE for the best paper bridging theory and applications, and two awards for the best paper published in the Transactions on CAS and CAD, three best paper awards and one best presentation awards at the Design Automation Conference. In 2001, he was given the prestigious Kaufman Award of the Electronic Design Automation Council for pioneering contributions to EDA. He is an author of over 700 papers and 15 books in the area of design tools and methodologies, large-scale systems, embedded controllers, hybrid systems and innovation. Dr. Sangiovanni-Vincentelli has been a Fellow of the IEEE since 1982 and a Member of the National Academy of Engineering, the highest honor bestowed upon a US engineer, since 1998.     

优化系统低功耗需要新型电源设计工具支持

低功耗问题已成为设计研发人员优化系统的关键目标,由于缺乏工具,过去人们难以简单地评估能量的效率,对能量效率进行优化那就更为难上之难.     

在ASIC设计中的功耗分析与优化设计

分析了 ＣＭＯＳ数字专用集成电路功耗的来源,给出了半定制数字专用集成电路功耗的计算方法以及功耗优化设计的方法。     

A scheduling approach for design activities in concurrentengineering

This paper presents an optimization scheduling approach for concurrent design projects, in which activities may be executed in more than one operating mode and renewable as well as nonrenewable resources exist. Research on the development of a scheduling approach for concurrent scheduling is expected to shorten development lead time, minimize cost, and eliminate unnecessary redesign periods. In this paper, an integrated criterion function is proposed to ensure optimal concurrent scheduling and effective utilization of resources along with fluent delivery of information. In the criterion function, some key factors such as time order, resources, lead time and overlapping time of activities, which can make concurrent activities execute successfully, are taken into account adequately. Besides, two cruxes in concurrent engineering-role allocation, prerelease, and feedback revision process are discussed in detail. The example is part of a certain product development process, and the scheduling results demonstrate that the proposed algorithm is feasible     

陆基红外探测系统遮光罩优化设计

为降低陆基红外探测系统遮光罩自身辐射的大小,提出一种遮光罩优化设计方法。该方法将传统遮光罩的一级消光部分设计为多组相互垂直的反射面,入射到反射面上的杂散辐射光线被反向反射出遮光罩,外部杂散光得到抑制;同时,因为反射面热辐射率低,减小了由于遮光罩自身辐射引起的杂散光。详细介绍了遮光罩的优化设计方法,并结合实例使用TRACEPRO软件进行建模与仿真,计算了优化后遮光罩的PST值和自身热辐射大小。分析结果表明,与传统的遮光罩相比,优化后的遮光罩自身热辐射降低一个数量级,且其PST大小能够满足陆基红外探测系统外部杂散辐射的抑制水平。     

论有效推进质量改善小组活动的激励法

本文从实践运用需求出发，以诺基亚实际开展的成功事例，论述了激励法对促进质量改善小组活动的有效性。     

Protocol design for scalable and reliable group rekeying

We present the design and specification of a protocol for scalable and reliable group rekeying together with performance evaluation results. The protocol is based upon the use of key trees for secure groups and periodic batch rekeying. At the beginning of each rekey interval, the key server sends a rekey message to all users consisting of encrypted new keys (encryptions, in short) carried in a sequence of packets. We present a scheme for identifying keys, encryptions, and users, and a key assignment algorithm that ensures that the encryptions needed by a user are in the same packet. Our protocol provides reliable delivery of new keys to all users eventually. It also attempts to deliver new keys to all users with a high probability by the end of the rekey interval. For each rekey message, the protocol runs in two steps: a multicast step followed by a unicast step. Proactive forward error correction (FEC) multicast is used to reduce delivery latency. Our experiments show that a small FEC block size can be used to reduce encoding time at the server without increasing server bandwidth overhead. Early transition to unicast, after at most two multicast rounds, further reduces the worst-case delivery latency as well as user bandwidth requirement. The key server adaptively adjusts the proactivity factor based upon past feedback information; our experiments show that the number of NACKs after a multicast round can be effectively controlled around a target number. Throughout the protocol design, we strive to minimize processing and bandwidth requirements for both the key server and users.     

Protocol design for mobile radio group communications oversatellite

A protocol design for a mobile radio service supporting half-duplex push-to-talk voice communications over mobile satellite systems is presented. The service enables a closed group of mobile radio users to communicate among themselves, so that a transmission from any user is received by all. A key issue is the efficient utilization of satellite channels. Demand-assignment multiple access (DAMA) is employed to allocate channels only to those user groups in active sessions of conversations. Owing to the unique characteristics of the half-duplex point-to-multipoint group communications, a new DAMA protocol is proposed for this service. Within a channel assigned to a user group, access contentions exacerbated by very long round-trip delay can occur. A signaling protocol is devised to arbitrate access contentions so as to improve the utilization of the assigned channel. The proposed access control protocol offers 65% or 18% improvement in throughput capacity compared to manual carrier-sensed access without and with collision detection, respectively     

一种自适应实时事务并发控制新方法

传统的基于锁的并发控制机制重点考虑数据的一致性和事务的并发度,不能很好地满足实时数据库系统对时态一致性的要求.结合锁,多版本和有效性确认等并发控制机制,提出了一种并发控制的新方法——自适应多版本实时事务并发控制方法:AMVCC.此并发控制方法可根据具体情况自适应地采用不同的并发控制机制,能够有效提高事务的并发度和截止时间内完成事务的数量.通过可行性分析知:此方法在性能上优于传统基于锁的并发控制方法.     

A dynamic and integrated concurrency control for distributeddatabases

An integrated approach to concurrency control adaptively allows classical pessimistic (two-phase locking) or optimistic (using certification) approaches. The principles for a distributed integrated method controlling both locking and optimistic transactions are defined. The implementation of these principles leads to a method for constructing the serialization order of transactions, using their conflicts. This dynamic construction prevents the systematic rejection of old (long) readers, as in the multiversion methods. On the other hand, applying Thomas' rule to control the write conflicts permits the presence of old (long) writers     

国际漫游用户优选运营商网络的实现方法研究

文章探讨并提供了一种简单高效的国际漫游网络优选解决方案。在该解决方案中,归属网络运营商用户可以在漫游地自动注册到拥有高优先级的网络,归属网络运营商可以控制这一过程,从而实现其对国际漫游用户的可管可控。该方案基于现网的HLR网元来实现,无需部署新网元,投资少,见效快,对现有网络基本上没有影响,值得运营商实验、部署。     

Optimizing the joint transmit and receive MMSE design using mode selection

To approach the potential multiple-input multiple-output (MIMO) capacity while optimizing the system bit-error rate (BER) performance, the joint transmit and receive minimum mean squared error (joint Tx/Rx MMSE) design has been proposed. It is the optimal linear scheme for spatial multiplexing MIMO systems, assuming a fixed number of spatial streams p as well as fixed modulation and coding across these spatial streams. However, the number of spatial streams has been arbitrarily chosen and fixed, which may lead to an inefficient power allocation strategy and a poor BER performance. In this paper, we relax the constraint of fixed number of streams p and optimize this value for the current channel realization, under the constraints of fixed average total transmit power P/sub T/ and fixed rate R, what we refer to as mode selection . Based on the observation of the existence of a dominant optimal number of streams value for the considered Rayleigh flat-fading MIMO channel model, we further propose an "average" mode selection that avoids the per-channel adaptation through using the latter dominant value for all channel realizations. Finally, we exhibit the significant BER improvement provided by our mode selection over the conventional joint Tx/Rx MMSE design. Such significant improvement is due to the better exploitation of the MIMO spatial diversity and the more efficient power allocation enabled by our mode selection.     

Research on concurrency control algorithm for real-time collaborative editing systems

Real-time collaborative editing systems are important groupware tools in the computer supported cooperative work (CSCW) field. They support geographically dispersed users to edit shared files, graphics, etc. simultaneously. Currently popular real-time collaborative editing systems mostly use plain text data for edit and synchronization, and the corresponding operations are deleting, adding or modifying characters. The data acquisition system's metadata in this article is the module, such as deleting, adding or modifying a certain question. On the basis of differential synchronization algorithms and generic operation transformation (GOT) algorithm, this paper proposes a new concurrency control algorithm differential synchronization and generic operation transformation control algorithm (DSGOT).     

On the optimum design of unitary cyclic group space-time codes

In this letter, based on the exact pairwise-error probability, we derive the union bound on the symbol-error probability (SEP) of the differential unitary space-time (DUST) modulation employing group codes. Instead of using the rank-and-determinant or Euclidean distance criteria, we optimize the cyclic group codes such that the union bound on the SEP is minimized for a predetermined scenario, taking into account the number of transmit and receive antennas and the operating signal-to-noise ratio (SNR). Our simulation results show that for a wide range of SNRs, the codes with the minimum union bound for a particular SNR outperform the codes designed based on rank-and-determinant or Euclidean distance criteria.     

Optimizing the choice of influential nodes for diffusion on a social network

An optimization approach is taken to locating the optimal set of initial contacts in a social network to maximize the number of total network members reached by a message. It is assumed that initial contacts are costly and that the number of initial contacts must be minimized simultaneously with maximizing the total number of network members contacted. A bi‐objective probabilistic integer programming model is developed that assumes that actors are heterogeneous in the probability that they will pass messages along their ego networks. Considering the complexity of solving the proposed model, it reformulated as a pure integer programming model. The algorithm is illustrated by the analysis of message passing in a short‐message system (texting) among university students. Copyright © 2015 John Wiley & Sons, Ltd.     

基于遗传算法的载体上共形天线阵列优化

基于载体上共形天线相控阵列的优化综合由于计算时间长,一般不会采用GA方法优化,主要原因就是个体适应度的计算通常需要对整个天线阵列进行一次全波分析.但是本文预计算单元在阵列环境中方向图,利用相控阵理论中的单元在阵列环境中的方向图直接叠加的方法,计算个体适应度,可以大大加快求解个体适应度的速度,为直接使用GA方法优化共形天线阵列提供了可能.该方法既考虑了载体的影响又考虑了单元之间耦合的影响.通过数值实验可以看出,该方法能够大大的加快优化速度,而且优化结果与全波分析的结果能够很好的吻合.