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8661-8680hit(21534hit)

  • An Autonomic Connection Scheme for High Service Availability

    Daekeun MOON  Jinho PARK  Hagbae KIM  

     
    LETTER-Dependable Computing

      Vol:
    E93-D No:3
      Page(s):
    639-642

    In large-scale industrial plants, the process control system has multiple system servers to provide seamless services to plant operators irrespective of any system server's failure. In this paper, we present an autonomic connection scheme between the system server and the Human-Machine Interface application (HMI) without additional configuration. The proposed scheme is based on the concept of autonomic computing, supporting the fault-tolerant and/or load-balancing features. Finally, the mathematical analysis shows that the proposed scheme can provide high availability of services to users.

  • Methods for Avoiding the Checkerboard Distortion Caused by Finite Word Length Error in Multirate System

    Hiroaki IWAI  Masahiro IWAHASHI  Hitoshi KIYA  

     
    LETTER-Digital Signal Processing

      Vol:
    E93-A No:3
      Page(s):
    631-635

    We propose two methods for avoiding the checkerboard distortion which is caused by finite word length error. The first method derives the bit length of filter coefficients required for avoiding the checkerboard distortion under a certain word length. In the second method, the checkerboard distortion can be avoided by using the cascade structure which consists of zero-hold kernel and a time-invariant filter factorized from a filter with structure for avoiding the checkerboard distortion under linear systems. It is demonstrated by simulations that we can avoid the checkerboard distortion by using these proposed methods.

  • Architectures and Technologies for the Future Mobile Internet Open Access

    Dipankar RAYCHAUDHURI  

     
    INVITED LETTER

      Vol:
    E93-B No:3
      Page(s):
    436-441

    This position paper outlines the author's view on architectural directions and key technology enablers for the future mobile Internet. It is pointed out that mobile and wireless services will dominate Internet usage in the near future, and it is therefore important to design next-generation network protocols with features suitable for efficiently serving emerging wireless scenarios and applications. Several key requirements for mobile/wireless scenarios are identified - these include new capabilities such as dynamic spectrum coordination, cross-layer support, disconnection tolerant routing, content addressing, and location awareness. Specific examples of enabling technologies which address some of these requirements are given from ongoing research projects at WINLAB. Topics covered briefly include wireless network virtualization, the cache-and-forward (CNF) protocol, geographic (GEO) protocol stack, cognitive radio protocols, and open networking testbeds.

  • An Efficient Authentication Protocol for WLAN Mesh Networks in Trusted Environment

    Zhuo MA  Jianfeng MA  SangJae MOON  Xinghua LI  

     
    PAPER

      Vol:
    E93-D No:3
      Page(s):
    430-437

    Trusted Network Connect provides the functionality of the platform authentication and integrity verification which is crucial for enhancing the security of authentication protocols. However, applying this functionality directly to concrete authentications is susceptible to unknown attacks and efficiency degradation. In this paper, we propose TWMAP, a novel authentication protocol for WLAN Mesh networks in a trusted environment which completed the platform authentication and integrity verification during the user authentication. And, the Schnorr asymmetric signature scheme is utilized to reduce the overhead of the client. The security properties of the new protocol are examined using the Universally Composable Security model. The analytic comparisons and simulation results show that the new protocol is very efficient in both computing and communication costs.

  • Pattern Mapping Method for Low Power BIST Based on Transition Freezing Method

    Youbean KIM  Jaewon JANG  Hyunwook SON  Sungho KANG  

     
    LETTER-Dependable Computing

      Vol:
    E93-D No:3
      Page(s):
    643-646

    Proposed in this paper is a low power BIST architecture using the pattern mapping method based on the transition freezing method. The transition freezing method generates frozen patterns dynamically according to the transition tendency of an LFSR. This leads to an average power reduction of 60%. However, the patterns have limitations of 100% fault coverage due to random resistant faults. Therefore, in this paper, those faults are detected by mapping useless patterns among frozen patterns to the patterns generated by an ATPG. Throughout the scheme, 100% fault coverage is achieved. Moreover, we have reduced the amount of applied patterns, the test time, and the power dissipation.

  • On the Security of RFID Group Scanning Protocols

    Duc Nguyen DANG  Kwangjo KIM  

     
    LETTER

      Vol:
    E93-D No:3
      Page(s):
    528-530

    A RFID group scanning protocol enables a RFID reader to produce a proof of co-existence of multiple RFID tags. This type of protocol is also referred to as yoking-proof, grouping-proof and co-existence proof. In this letter, we show that all of the previous group scanning protocols are vulnerable to relay attack.

  • HIMALIS: Heterogeneity Inclusion and Mobility Adaptation through Locator ID Separation in New Generation Network

    Ved P. KAFLE  Masugi INOUE  

     
    PAPER

      Vol:
    E93-B No:3
      Page(s):
    478-489

    The current Internet is not capable of meeting the future communication requirements of society, i.e., reliable connectivity in a ubiquitous networking environment. The shortcomings of the Internet are due to the lack of support for mobility, multihoming, security and heterogeneous network layer protocols in the original design. Therefore, to provide ubiquitous networking facilities to the society for future innovation, we have to redesign the future Internet, which we call the New Generation Network. In this paper, we present the Heterogeneity Inclusion and Mobility Adaptation through Locator ID Separation (HIMALIS) architecture for the New Generation Network. The HIMALIS architecture includes a new naming scheme for generating host names and IDs. It also includes a logical control network to store and distribute bindings between host names, IDs, locators and other information useful for providing support for network operation and control. The architecture uses such information to manage network dynamism (i.e., mobility, multihoming) and heterogeneity in network layer protocols. We verify the basic functions of the architecture by implementing and testing them using a testbed system.

  • Global Asymptotic Stability of FAST TCP Network with Heterogeneous Feedback Delays

    Joon-Young CHOI  Kyungmo KOO  Jin Soo LEE  

     
    PAPER-Network

      Vol:
    E93-B No:3
      Page(s):
    571-580

    We consider a single-link multi-source network with FAST TCP sources. We adopt a continuous-time dynamic model for FAST TCP sources, and propose a static model to adequately describe the queuing delay dynamics at the link. The proposed model turns out to have a structure that reveals the time-varying network feedback delay, which allows us to analyze FAST TCP with due consideration of the time-varying network feedback delay. Based on the proposed model, we establish sufficient conditions for the boundedness of congestion window of each source and for the global asymptotic stability. The asymptotic stability condition shows that the stability property of each source is affected by all other sources sharing the link. Simulation results illustrate the validity of the sufficient condition for the global asymptotic stability.

  • Time Difference Amplifier with Robust Gain Using Closed-Loop Control

    Toru NAKURA  Shingo MANDAI  Makoto IKEDA  Kunihiro ASADA  

     
    PAPER

      Vol:
    E93-C No:3
      Page(s):
    303-308

    This paper presents a Time Difference Amplifier (TDA) that amplifies the input time difference into the output time difference. Cross coupled chains of variable delay cells with the same number of stages are applicable for TDA, and the gain is adjusted via the closed-loop control. The TDA was fabricated using 65 nm CMOS and the measurement results show that the time difference gain is 4.78 at a nominal power supply while the designed gain is 4.0. The gain is stable enough to be less than 1.4% gain shift under 10% power supply voltage fluctuation.

  • A Low-Complexity Antenna Selection Scheme in MIMO Systems

    Jung-Chieh CHEN  

     
    LETTER-Communication Theory and Signals

      Vol:
    E93-A No:3
      Page(s):
    651-655

    This paper considers the use of an antenna selection mechanism to reduce the cost of multiple analog transmit/receive chains in multiple-input multiple-output (MIMO) systems. With the optimal antenna selection scheme, radio-frequency chains can optimally connect with the best subset of transmitter and/or receiver antennas. However, the optimal antenna selection algorithm requires an exhaustive search of all possible combinations to find the optimum subset at the transmitter and/or receiver, thus resulting in high complexity. In order to reduce the computational load while still maximizing channel capacity, we introduce the simulated annealing (SA) method, an effective algorithm that solves various combinatorial optimization problems, to search the optimal subset. The simulation results show that the performance of the proposed SA method provides almost the same channel capacity as that of the optimal exhaustive search algorithm while maintaining low complexity.

  • An Ultrasonic and Air Pressure Sensing System for Detection of Behavior before Getting out of Bed Aided by Fuzzy Theory

    Hayato YAMAGUCHI  Hiroshi NAKAJIMA  Kazuhiko TANIGUCHI  Syoji KOBASHI  Yutaka HATA  

     
    PAPER-Computation and Computational Models

      Vol:
    E93-D No:3
      Page(s):
    542-549

    This paper proposes a sensing system for a behavior detection system using an ultrasonic oscillosensor and an air pressure sensor. The ultrasonic oscillosensor sensor has a cylindrical tank filled with water. It detects the vibration of the target object from the signal reflected from the water surface. This sensor can detect a biological vibration by setting to the bottom bed frame. The air pressure sensor consists of a polypropylene sheet and an air pressure sensor, and detects the pressure information by setting under the bed's mattress. An increase (decrease) in the load placed on the bed is detected by the increase (decrease) in the pressure of the air held in the tube attached to the sheet. We propose a behavior detection system using both sensors, complementally. The system recognizes three states (nobody in bed, keeping quiet in bed, moving in bed) using both sensors, and we detect the behavior before getting out of bed by recognized these states. Fuzzy logic plays a primary role in the system. As the fundamental experiment, we applied the system to five healthy volunteers, the system successfully recognized three states, and detected the behavior before getting out of bed. As the clinical experiment, we applied the system to four elderly patients with dementia, the system exactly detected the behavior before getting out of the bed with enough time for medical care support.

  • Design and Implementation of High-Speed Input-Queued Switches Based on a Fair Scheduling Algorithm

    Qingsheng HU  Hua-An ZHAO  

     
    PAPER

      Vol:
    E93-C No:3
      Page(s):
    279-287

    To increase both the capacity and the processing speed for input-queued (IQ) switches, we proposed a fair scalable scheduling architecture (FSSA). By employing FSSA comprised of several cascaded sub-schedulers, a large-scale high performance switches or routers can be realized without the capacity limitation of monolithic device. In this paper, we present a fair scheduling algorithm named FSSA_DI based on an improved FSSA where a distributed iteration scheme is employed, the scheduler performance can be improved and the processing time can be reduced as well. Simulation results show that FSSA_DI achieves better performance on average delay and throughput under heavy loads compared to other existing algorithms. Moreover, a practical 64 64 FSSA using FSSA_DI algorithm is implemented by four Xilinx Vertex-4 FPGAs. Measurement results show that the data rates of our solution can be up to 800 Mbps and the tradeoff between performance and hardware complexity has been solved peacefully.

  • Impact of Self-Heating in Wire Interconnection on Timing

    Toshiki KANAMOTO  Takaaki OKUMURA  Katsuhiro FURUKAWA  Hiroshi TAKAFUJI  Atsushi KUROKAWA  Koutaro HACHIYA  Tsuyoshi SAKATA  Masakazu TANAKA  Hidenari NAKASHIMA  Hiroo MASUDA  Takashi SATO  Masanori HASHIMOTO  

     
    BRIEF PAPER

      Vol:
    E93-C No:3
      Page(s):
    388-392

    This paper evaluates impact of self-heating in wire interconnection on signal propagation delay in an upcoming 32 nm process technology, using practical physical parameters. This paper examines a 64-bit data transmission model as one of the most heating cases. Experimental results show that the maximum wire temperature increase due to the self-heating appears in the case where the ratio of interconnect delay becomes largest compared to the driver delay. However, even in the most significant case which induces the maximum temperature rise of 11.0, the corresponding increase in the wire resistance is 1.99% and the resulting delay increase is only 1.15%, as for the assumed 32 nm process. A part of the impact reduction of wire self-heating on timing comes from the size-effect of nano-scale wires.

  • Inductor and TSV Design of 20-V Boost Converter for Low Power 3D Solid State Drive with NAND Flash Memories

    Tadashi YASUFUKU  Koichi ISHIDA  Shinji MIYAMOTO  Hiroto NAKAI  Makoto TAKAMIYA  Takayasu SAKURAI  Ken TAKEUCHI  

     
    PAPER

      Vol:
    E93-C No:3
      Page(s):
    317-323

    Two essential technologies for a 3D Solid State Drive (3D-SSD) with a boost converter are presented in this paper. The first topic is the spiral inductor design which determines the performance of the boost converter, and the second is the effect of TSV's on the boost converter. These techniques are very important in achieving a 3D-SSD with a boost converter. In the design of the inductor, the on-board inductor from 250 nH to 320 nH is the best design feature that meets all requirements, including high output voltage above 20 V, fast rise time, low energy consumption, and area smaller than 25 mm2. The use of a boost converter with the proposed inductor leads to a reduction of the energy consumption during the write operation of the proposed 1.8-V 3D-SSD by 68% compared with the conventional 3.3-V 3D-SSD with the charge pump. The feasibility of 3D-SSD's with Through Silicon Vias (TSV's) connections is also discussed. In order to maintain the advantages of the boost converter over the charge pump, the reduction of the parasitic resistance of TSV's is very important.

  • Improved SISO MMSE Detection for Joint Coded-Precoded OFDM under Imperfect Channel Estimation

    Guomei ZHANG  Shihua ZHU  Feng LI  Pinyi REN  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:3
      Page(s):
    757-761

    An improved soft-input soft-output (SISO) minimum mean-squared error (MMSE) detection method is proposed for joint coding and precoding OFDM systems under imperfect channel estimation. Compared with the traditional mismatched detection which uses the channel estimate as its exact value, the signal model of the proposed detector is more accurate and the influence of channel estimation error (CEE) can be effectively mitigated. Simulations indicate that the proposed scheme can improve the bit error rate (BER) performance with fewer pilot symbols.

  • Interoperability Experiment of VLAN Tag Swapped Ethernet and Transmitting High Definition Video through the Layer-2 LSP between Japan and Belgium Open Access

    Sho SHIMIZU  Wouter TAVERNIER  Kou KIKUTA  Masahiro NISHIDA  Daisuke ISHII  Satoru OKAMOTO  Didier COLLE  Mario PICKAVET  Piet DEMEESTER  Naoaki YAMANAKA  

     
    LETTER-Network

      Vol:
    E93-B No:3
      Page(s):
    736-740

    The first global interoperability experiment of GMPLS controlled Ethernet with VLAN tag swapping between two different implementations is successfully demonstrated. High definition video streaming is realized through a newly established Layer 2 Label Switched Path (L2-LSP). The results of this experiment can be applied to designing reliable Layer 2 networks.

  • A Novel Resource Allocation and Admission Control in LTE Systems

    Abhishek ROY  Navrati SAXENA  Jitae SHIN  

     
    LETTER-Network

      Vol:
    E93-B No:3
      Page(s):
    721-724

    In this letter we propose a novel resource allocation and admission control strategy for OFDMA-based emerging LTE systems. Considering users' reneging and migration between service providers, we first prove that the optimal resource allocation problem, which maximizes the service provider's gross income is, NP-complete. Subsequently, we propose two different heuristics based on dynamic programming and greedy algorithms to get a near-optimal resource allocation and admission control strategy in computationally feasible time. Simulation results point out that the solutions offer increased gross income of the service provider, while offering low latency, adequate throughput and session acceptance.

  • NICT New-Generation Network Vision and Five Network Targets Open Access

    Nozomu NISHINAGA  

     
    INVITED LETTER

      Vol:
    E93-B No:3
      Page(s):
    446-449

    The National Institute of Information and Communications Technology (NICT) vision and five network targets of research and development (R&D) of the NeW-Generation Network (NWGN) are presented in this letter. The NWGN is based on new design concepts that look beyond the next generation network (NGN). The NWGN will maintain the sustainability of our prosperous civilization and help resolve various social issues and problems by using information and communication technologies (ICTs). NICT's vision for NWGN is also presented in this letter. Based on this vision, 19 items concerning social issues and future social outlook are analyzed, and the functional requirements of the NWGN are extracted. The requirements are refined and categorized into five network targets that must be developed for realizing the vision.

  • Distributed Channel Assignment Scheme Supporting Various Traffic Loads in Microcellular Systems

    Seung-young PARK  Hyun-hee LEE  Kyung-goo JUNG  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:3
      Page(s):
    766-770

    In this letter, we propose a distributed channel assignment where each basestation selects a set of channels shared by multiple users through time domain scheduling for best effort services. The proposed scheme distributedly assigns the channels considering a cochannel interference from neighboring basestations and its own traffic load condition. The computer simulation demonstrates that the proposed scheme appropriately assigns the channels to the basestations taking into account these requirements.

  • Least-Squares Conditional Density Estimation

    Masashi SUGIYAMA  Ichiro TAKEUCHI  Taiji SUZUKI  Takafumi KANAMORI  Hirotaka HACHIYA  Daisuke OKANOHARA  

     
    PAPER-Pattern Recognition

      Vol:
    E93-D No:3
      Page(s):
    583-594

    Estimating the conditional mean of an input-output relation is the goal of regression. However, regression analysis is not sufficiently informative if the conditional distribution has multi-modality, is highly asymmetric, or contains heteroscedastic noise. In such scenarios, estimating the conditional distribution itself would be more useful. In this paper, we propose a novel method of conditional density estimation that is suitable for multi-dimensional continuous variables. The basic idea of the proposed method is to express the conditional density in terms of the density ratio and the ratio is directly estimated without going through density estimation. Experiments using benchmark and robot transition datasets illustrate the usefulness of the proposed approach.

8661-8680hit(21534hit)