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7861-7880hit(18690hit)

  • 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.

  • Split Capacitor DAC Mismatch Calibration in Successive Approximation ADC

    Yanfei CHEN  Xiaolei ZHU  Hirotaka TAMURA  Masaya KIBUNE  Yasumoto TOMITA  Takayuki HAMADA  Masato YOSHIOKA  Kiyoshi ISHIKAWA  Takeshi TAKAYAMA  Junji OGAWA  Sanroku TSUKAMOTO  Tadahiro KURODA  

     
    PAPER

      Vol:
    E93-C No:3
      Page(s):
    295-302

    Charge redistribution based successive approximation (SA) analog-to-digital converter (ADC) has the advantage of power efficiency. Split capacitor digital-to-analog converter (CDAC) technique implements two sets of binary-weighted capacitor arrays connected by a bridge capacitor so as to reduce both input load capacitance and area. However, capacitor mismatches degrade ADC performance in terms of DNL and INL. In this work, a split CDAC mismatch calibration method is proposed. A bridge capacitor larger than conventional design is implemented so that a tunable capacitor can be added in parallel with the lower-weight capacitor array to compensate for mismatches. To guarantee correct CDAC calibration, comparator offset is cancelled using a digital timing control charge compensation technique. To further reduce the input load capacitance, an extra unit capacitor is added to the higher-weight capacitor array. Instead of the lower-weight capacitor array, the extra unit capacitor and the higher-weight capacitor array sample analog input signal. An 8-bit SA ADC with 4-bit + 4-bit split CDAC has been implemented in a 65 nm CMOS process. The ADC has an input capacitance of 180 fF and occupies an active area of 0.03 mm2. Measured results of +0.2/-0.3LSB DNL and +0.3/-0.3LSB INL have been achieved after calibration.

  • Fixed Point Data Type Modeling for High Level Synthesis

    Benjamin CARRION SCHAFER  Yusuke IGUCHI  Wataru TAKAHASHI  Shingo NAGATANI  Kazutoshi WAKABAYASHI  

     
    PAPER

      Vol:
    E93-C No:3
      Page(s):
    361-368

    A methodology to automatically convert fixed point data type representations into integer data types for high level synthesis is presented in this work. Our method converts all major C operations using fixed point data types into integer data types, models quantization and overflow modes, type conversion and casting. The conversion rule for each operation is described in detail as well as a regression test environment with 600 test cases to validate the method and to verify the correctness of each conversion compared to the same cases written in SystemC. The test environment converts each test case with fixed point data types into integer data types and synthesizes them with a high level synthesis tool to generate RTL. An RTL simulation is ran and the results in turn compared to the SystemC's OSCI simulation. For all of the 600 test cases the RTL simulation results matched the SystemC results proving that each conversion is accurately modeled. A larger real test case is also presented to validate the conversion method in a complex case.

  • 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.

  • Utterance Verification Using State-Level Log-Likelihood Ratio with Frame and State Selection

    Suk-Bong KWON  Hoirin KIM  

     
    LETTER-Speech and Hearing

      Vol:
    E93-D No:3
      Page(s):
    647-650

    This paper suggests utterance verification system using state-level log-likelihood ratio with frame and state selection. We use hidden Markov models for speech recognition and utterance verification as acoustic models and anti-phone models. The hidden Markov models have three states and each state represents different characteristics of a phone. Thus we propose an algorithm to compute state-level log-likelihood ratio and give weights on states for obtaining more reliable confidence measure of recognized phones. Additionally, we propose a frame selection algorithm to compute confidence measure on frames including proper speech in the input speech. In general, phone segmentation information obtained from speaker-independent speech recognition system is not accurate because triphone-based acoustic models are difficult to effectively train for covering diverse pronunciation and coarticulation effect. So, it is more difficult to find the right matched states when obtaining state segmentation information. A state selection algorithm is suggested for finding valid states. The proposed method using state-level log-likelihood ratio with frame and state selection shows that the relative reduction in equal error rate is 18.1% compared to the baseline system using simple phone-level log-likelihood ratios.

  • Distributed Video Coding with Multiple Side Information Sets

    Jung Ah PARK  Doug Young SUH  Gwang-Hoon PARK  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E93-D No:3
      Page(s):
    654-657

    This letter proposes a method to retrieve the original image X out of multiple sets of SI (Side Information) in distributed video coding (DVC). Using Turbo decoding methods, the most reliable segments from the decoded Yi's were selected for the composition of Y∞, whose conditional entropy H(X| Y∞) became much lower than any individual conditional entropy H(X| Yi). This proposal has improved the peak signal-to-noise ratio (PSNR) by 1.1 to 1.8 dB, compared to the conventional single SI-based approach.

  • Robust Object Tracking via Combining Observation Models

    Fan JIANG  Guijin WANG  Chang LIU  Xinggang LIN  Weiguo WU  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E93-D No:3
      Page(s):
    662-665

    Various observation models have been introduced into the object tracking community, and combining them has become a promising direction. This paper proposes a novel approach for estimating the confidences of different observation models, and then effectively combining them in the particle filter framework. In our approach, spatial Likelihood distribution is represented by three simple but efficient parameters, reflecting the overall similarity, distribution sharpness and degree of multi peak. The balance of these three aspects leads to good estimation of confidences, which helps maintain the advantages of each observation model and further increases robustness to partial occlusion. Experiments on challenging video sequences demonstrate the effectiveness of our approach.

  • 4WARD: A European Perspective towards the Future Internet Open Access

    Marcus BRUNNER  Henrik ABRAMOWICZ  Norbert NIEBERT  Luis M. CORREIA  

     
    INVITED LETTER

      Vol:
    E93-B No:3
      Page(s):
    442-445

    In this paper, we describe several approaches to address the challenges of the network of the future. Our main hypothesis is that the Future Internet must be designed for the environment of applications and transport media of the 21st century, vastly different from the initial Internet's life space. One major requirement is the inherent support for mobile and wireless usage. A Future Internet should allow for the fast creation of diverse network designs and paradigms and must also support their co-existence at run-time. We detail the technical and business scenarios that lead the development in the EU FP7 4WARD project towards a framework for the Future Internet.

  • Network Virtualization as Foundation for Enabling New Network Architectures and Applications Open Access

    Akihiro NAKAO  

     
    INVITED LETTER

      Vol:
    E93-B No:3
      Page(s):
    454-457

    Network virtualization has become a common research topic that many researchers consider a basis for defining a new generation network architectures. In this paper, we attempt to clarify the concept of network virtualization with its brief history, to introduce the benefit of network virtualization for the future network, to posit our strong belief in that the future network should adopt a form of a meta-architecture that accommodates multiple competing multiple architectures, and to identify challenges to achieving this architecture.

  • Temperature Effects on Anomalous Radio Duct Propagation in Korean Coastal Area

    Yong-Ki KWON  Man-Seop LEE  Hakyong KIM  

     
    LETTER-Antennas and Propagation

      Vol:
    E93-B No:3
      Page(s):
    784-787

    Atmospheric radio ducts can trap VHF/UHF radio waves and propagate them over long distances. 284.4625 MHz Japanese radio wave signal measurements show that the radio waves are propagated to Korea coastal regions when ground temperatures exceed 10C. This paper discusses the reasons for the existence of this critical temperature threshold.

  • AC Electric Field Communication for Human-Area Networking Open Access

    Yuichi KADO  Mitsuru SHINAGAWA  

     
    INVITED PAPER

      Vol:
    E93-C No:3
      Page(s):
    234-243

    We have proposed a human-area networking technology that uses the surface of the human body as a data transmission path and uses an AC electric field signal below the resonant frequency of the human body. This technology aims to achieve a "touch and connect" intuitive form of communication by using the electric field signal that propagates along the surface of the human body, while suppressing both the electric field radiating from the human body and mutual interference. To suppress the radiation field, the frequency of the AC signal that excites the transmitter electrode must be lowered, and the sensitivity of the receiver must be raised while reducing transmission power to its minimally required level. We describe how we are developing AC electric field communication technologies to promote the further evolution of a human-area network in support of ubiquitous services, focusing on three main characteristics, enabling-transceiver technique, application-scenario modeling, and communications quality evaluation. Special attention is paid to the relationship between electro-magnetic compatibility evaluation and regulations for extremely low-power radio stations based on Japan's Radio Law.

  • An Optimal Algorithm towards Successive Location Privacy in Sensor Networks with Dynamic Programming

    Baokang ZHAO  Dan WANG  Zili SHAO  Jiannong CAO  Keith C.C. CHAN  Jinshu SU  

     
    LETTER

      Vol:
    E93-D No:3
      Page(s):
    531-533

    In wireless sensor networks, preserving location privacy under successive inference attacks is extremely critical. Although this problem is NP-complete in general cases, we propose a dynamic programming based algorithm and prove it is optimal in special cases where the correlation only exists between p immediate adjacent observations.

  • A Time-Slicing Ring Oscillator for Capturing Time-Dependent Delay Degradation and Power Supply Voltage Fluctuation

    Takumi UEZONO  Kazuya MASU  Takashi SATO  

     
    PAPER

      Vol:
    E93-C No:3
      Page(s):
    324-331

    A time-slicing ring oscillator (TSRO) which captures time-dependent delay degradation due to periodic transient voltage drop on a power supply network is proposed. An impact of the supply voltage fluctuations, including voltage drop and overshoot, on logic circuit delay is evaluated as a change of oscillation frequency. The TSRO is designed using standard logic cells so that it can be placed almost anywhere in a digital circuit wherein supply voltage fluctuation is concerned. We also propose a new procedure for reconstructing supply voltage waveform. The procedure enables us to accurately monitor time-dependent, effective supply voltages. The -1 dB bandwidth of the TSRO is simulated to be 15.7 GHz, and measured time resolution is 131 ps. Measurement results of a test chip using 90-nm standard CMOS process successfully proved the feasibility of both delay degradation and effective supply voltage fluctuation measurements. Measurement of spatial voltage drop fluctuation is achieved.

  • LOPP: A Location Privacy Protected Anonymous Routing Protocol for Disruption Tolerant Network

    Xiaofeng LU  Pan HUI  Don TOWSLEY  Juhua PU  Zhang XIONG  

     
    PAPER

      Vol:
    E93-D No:3
      Page(s):
    503-509

    In this paper, we propose an anonymous routing protocol, LOPP, to protect the originator's location privacy in Delay/Disruption Tolerant Network (DTN). The goals of our study are to minimize the originator's probability of being localized (Pl) and maximize the destination's probability of receiving the message (Pr). The idea of LOPP is to divide a sensitive message into k segments and send each of them to n different neighbors. Although message fragmentation could reduce the destination's probability to receive a complete message, LOPP can decrease the originator's Pl. We validate LOPP on a real-world human mobility dataset. The simulation results show that LOPP can decrease the originator's Pl by over 54% with only 5.7% decrease in destination's Pr. We address the physical localization issue of DTN, which was not studied in the literature.

  • Design Guidelines for New Generation Network Architecture

    Hiroaki HARAI  Kenji FUJIKAWA  Ved P. KAFLE  Takaya MIYAZAWA  Masayuki MURATA  Masaaki OHNISHI  Masataka OHTA  Takeshi UMEZAWA  

     
    LETTER

      Vol:
    E93-B No:3
      Page(s):
    462-465

    Limitations are found in the recent Internet because a lot of functions and protocols are patched to the original suite of layered protocols without considering global optimization. This reveals that end-to-end argument in the original Internet was neither sufficient for the current societal network and nor for a sustainable network of the future. In this position paper, we present design guidelines for a future network, which we call the New Generation Network, which provides the inclusion of diverse human requirements, reliable connection between the real-world and virtual network space, and promotion of social potentiality for human emergence. The guidelines consist of the crystal synthesis, the reality connection, and the sustainable & evolutional guidelines.

  • Self-Organization Based Network Architecture for New Generation Networks Open Access

    Naoki WAKAMIYA  Masayuki MURATA  

     
    INVITED LETTER

      Vol:
    E93-B No:3
      Page(s):
    458-461

    A new generation network is requested to accommodate an enormous number of heterogeneous nodes and a wide variety of traffic and applications. To achieve higher scalability, adaptability, and robustness than ever before, in this paper we present new network architecture composed of self-organizing entities. The architecture consists of the physical network layer, service overlay network layer, and common network layer mediating them. All network entities, i.e. nodes and networks, behave in a self-organizing manner, where the global behavior emerges through their operation on local information and direct and/or indirect mutual interaction. The center of the architecture is so-called self-organization engines, which implement nonlinear self-organizing dynamics originating in biology, physics, and mathematics. In this paper, we also show some examples of self-organization engines.

  • 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.

  • HopRec: Hop-Based Recommendation Ability Enhanced Reputation Ranking in P2P Networks

    Yufeng WANG  Akihiro NAKAO  Jianhua MA  

     
    PAPER

      Vol:
    E93-D No:3
      Page(s):
    438-447

    As a concept stemmed from social field, we argued that, in P2P networks, peers' recommendation behaviors and functional behaviors should be explicitly separated, thus we propose the HopRec scheme which uses hop-based recommendation ability to improve the accuracy of reputation ranking in P2P networks. Our contributions lie in the following aspects: firstly, we adopt the simple but effective idea to infer peer's recommendation ability (RA): the farer away that peer is from the initial malicious seeds, the higher RA that peer should have; Then, the computation of reputation rankings appropriately reflects peer's different RA. The simulation results show that, in comparison with Eigentrust-like algorithms, HopRec can be robust to sybils and front peers attacks, and achieve significant performance improvement. Moreover, we compare HopRec with two related schemes, Poisonedwater and CredibleRank, and found that: in hospitable P2P environment, HopRec can obtain better performance than Poisonedwater, and can achieve the comparable performance as CredibleRank, with less computation overhead then CredibleRank. Finally, we also show that, if the initial good and malicious seeds could be selected based on peers' degrees, then HopRec and CredibleRank can achieve perfect performance.

  • A Band Extension Technique for Narrow-Band Telephony Speech Based on Full Wave Rectification

    Naofumi AOKI  

     
    LETTER-Network

      Vol:
    E93-B No:3
      Page(s):
    729-731

    This study investigates a band extension technique for narrow-band telephony speech. The proposed technique employs full wave rectification that nonlinearly generates high-band overtones from the low band. In order to improve the conventional technique, this study investigates a frame-by-frame gain control based on the estimation of gain parameter from narrow-band telephony speech. A subjective evaluation indicates that the proposed technique outperforms the conventional technique.

  • Antenna Switching Schemes for Downlink Time Switched Transmit Diversity with ARQ in Rayleigh Fading Channels

    Cha-Eul JEON  Seung-Hoon HWANG  

     
    LETTER-Terrestrial Radio Communications

      Vol:
    E93-B No:3
      Page(s):
    780-783

    For automatic repeat request (ARQ)-aided TSTD (Time Switched Transmit Diversity) system, a receiver sends the acknowledgement signal (ACK or NACK) to a transmitter in order to predict the condition of the channel. In this paper, two antenna switching schemes, in which the NACK trigger the transmit antenna switching in the proposed antenna switching patterns, are proposed for the TSTD with the ARQ in WCDMA LCR-TDD systems. In addition, the system performances are investigated. Simulation results demonstrate that the performances of the TSTD systems can be improved by applying the ARQ scheme. Furthermore, the performances of ARQ-aided TSTD systems may be significantly improved by applying the proposed antenna switching schemes, especially when the mobile's speed is low.

7861-7880hit(18690hit)