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[Keyword] PD(276hit)

121-140hit(276hit)

  • Forgery Attacks on Time-Stamp, Signed PDF and X.509 Certificate

    Kouichi ITOH  Tetsuya IZU  Wakaha OGATA  Takeshi SHIMOYAMA  Masahiko TAKENAKA  

     
    PAPER-Digital Signature

      Vol:
    E92-A No:1
      Page(s):
    67-75

    This paper studies two types of documents in which an adversary can forge a signature on a chosen document. One type is that a nonce is padded on an input document. The time-stamp protocol is a good example of this type. Another is a structured document (such as PS or PDF) whose contents are described in a body part and information (such as generated time and a generator) are in a meta part. In fact, this paper shows how to forge a time-stamp, a signature on a PDF and an X.509 certificate by the extended forgery attack and numerical examples. Forged signature by the original or the extended attacks is only accepted by the clients whose length check of zero-field is loosely implemented. As a result, we found that the latest versions of Adobe's Acrobat and Acrobat Reader accept the forged time-stamp and the forged signature on a PDF document. Target of this attack is RSASSA-PKCS1-v1_5, which does not have provable security. We also show the expanded attack might forge the signature of RSASSA-PSS, which has provable security, when the length check of zero-field is omitted or loosely implemented.

  • A Study on Temporal Dark Image Sticking in AC-PDP Using Vacuum-Sealing Method

    Choon-Sang PARK  Heung-Sik TAE  

     
    PAPER-Electronic Displays

      Vol:
    E92-C No:1
      Page(s):
    161-165

    Minimizing the residual impurity gases is a key factor for reducing temporal dark image sticking. Therefore, this paper uses a vacuum-sealing method that minimizes the residual impurity gases by enhancing the base vacuum level, and the resultant change in temporal dark image sticking is then examined in comparison to that with the conventional sealing method using 42-in. ac-PDPs with a high Xe (11%) content. As a result of monitoring the difference in the display luminance, infrared emission, and perceived luminance between the cells with and without temporal dark image sticking, the vacuum-sealing method is demonstrated to reduce temporal dark image sticking by decreasing the residual impurity gases and increasing the oxygen vacancy in the MgO layer. Furthermore, the use of a modified driving waveform along with the vacuum-sealing method is even more effective in reducing temporal dark image sticking.

  • Routing Autonomous Vehicles in the Improving Initial Task Assignment and Avoiding Deadlock Method

    Yusuke MORIHIRO  Toshiyuki MIYAMOTO  Sadatoshi KUMAGAI  

     
    PAPER

      Vol:
    E91-A No:11
      Page(s):
    3229-3236

    This paper discusses an on-line Tasks Assignment and Routing Problem (TARP) for Autonomous Transportation Systems (ATSs) in manufacturing systems. The TARP is a constrained version of the Pickup and Delivery Problem with Time Windows (PDPTW). In our former study, a cooperative algorithm, called the triple loop method, with autonomous distributed agents has been proposed. The Improving initial Task Assignment and Avoiding Deadlock method (ITAAD) is a faster algorithm than the triple loop method. In this paper, we propose a new vehicle routing method for the ITAAD. Results of computational experiments show effectiveness of the proposed routing method.

  • Improvement of Luminescent Characteristics of BaGd4Si3O13:Tb Green VUV Phosphor by F-Incorporation

    Atsushi KOBAYASHI  Takashi KUNIMOTO  Akira YAMANE  Koutoku OHMI  

     
    INVITED PAPER

      Vol:
    E91-C No:10
      Page(s):
    1542-1546

    Luminescent characteristics of BaGd4Si3O13:Tb phosphor powder including fluorine, which is synthesized at about 1000, have been investigated. This phosphor shows the green emission due to Tb3+ under VUV excitation. By incorporation of F ion based on low-temperature synthesis, the photoluminescence excitation band lying in the wavelength region from 130 to 170 nm increases drastically in comparison to BaGd4Si3O13:Tb phosphor synthesized at 1550. This phosphor is a candidate for a green PDP phosphor for both 147 nm resonance line and 172 nm excimer band of Xe plasma.

  • Post-Silicon Clock-Timing Tuning Based on Statistical Estimation

    Yuko HASHIZUME  Yasuhiro TAKASHIMA  Yuichi NAKAMURA  

     
    PAPER

      Vol:
    E91-A No:9
      Page(s):
    2322-2327

    In deep-submicron technologies, process variations can significantly affect the performance and yield of VLSI chips. As a countermeasure to the variations, post-silicon tuning has been proposed. Deskew, where the clock timing of flip-flops (FFs) is tuned by inserted programmable delay elements (PDEs) into the clock tree, is classified into this method. We propose a novel deskew method that decides the delay values of the elements by measuring a small amount of FFs' clock timing and presuming the rest of FFs' clock timings based on a statistical model. In addition, our proposed method can determine the discrete PDE delay value because the rewriting constraint satisfies the condition of total unimodularity.

  • A Dynamic Anchor-Area Scheme Using a Timer Value and a Movement List for PCS Networks

    In-Kap CHANG  Jung-Sik HONG  Ji-Pyo KIM  Chang-Hoon LIE  

     
    LETTER-Terrestrial Radio Communications

      Vol:
    E91-B No:9
      Page(s):
    3030-3032

    A dynamic anchor-area (DAA) scheme is proposed to reduce the location management cost for PCS networks. Based on an Intra-LA location update (LU) scheme, the proposed DAA scheme utilizes a given timer value and a movement list. The DAA scheme considers a wider variety of mobile terminal's movement pattern than the previous intra-LA LU scheme. Simulations confirm that the proposed scheme offers a significant reduction in the location management cost.

  • A GaAs SOI HEMT Fabricated by Fluidic Self-Assembly and Its Application to an RF-Switch

    Koichi MAEZAWA  Ikuo SOGA  Shigeru KISHIMOTO  Takashi MIZUTANI  Kazuhiro AKAMATSU  

     
    PAPER-Novel Integration Technology

      Vol:
    E91-C No:7
      Page(s):
    1025-1030

    The heterogeneous integration of GaAs HEMTs on a polyimide-covered AlN ceramic substrate was demonstrated using a fluidic self-assembly (FSA) technique. We used thin device blocks for the FSA, which have various advantages. In particular, they can reduce the drain-source capacitance Cds of the assembled HEMTs if the substrate has a low dielectric constant. This is a novel kind of semiconductor-on-insulator (SOI) technology. The dc and RF properties of the GaAs HEMTs on the polyimide/AlN substrate were studied and the reduction of Cds was confirmed. This technique was successfully applied to the SPDT switch, where a low Cds is essential for good isolation.

  • New Closed-Form of the Largest Eigenvalue PDF for Max-SNR MIMO System Performances

    Jonathan LETESSIER  Baptiste VRIGNEAU  Philippe ROSTAING  Gilles BUREL  

     
    PAPER-Communication Theory and Signals

      Vol:
    E91-A No:7
      Page(s):
    1791-1796

    Multiple-input multiple-output (MIMO) maximum-SNR (max-SNR) system employs the maximum ratio combiner (MRC) at the receiver side and the maximum ratio transmitter (MRT) at the transmitter side. Its performances highly depend on MIMO channel characteristics, which vary according to both the number of antennas and their distribution between the transmitter and receiver sides. By using the decomposition of the ordered Wishart distribution in the uncorrelated Rayleigh case, we derived a closed-form expression of the largest eigenvalue probability density function (PDF). The final result yields to an expression form of the PDF where polynomials are multiplied by exponentials; it is worth underlining that, though this form had been previously observed for given couples of antennas, to date no formally-written closed-form was available in the literature for an arbitrary couple. Then, this new expression permits one to quickly and easily get the well known largest eigenvalue PDF and use it to determine the binary error probability (BEP) of the max-SNR.

  • The Ridged Cross-Junction Multiple-Way Power Divider for Small Blockage and Symmetrical Slot Arrangement in the Center Feed Single-Layer Slotted Waveguide Array

    Yasuhiro TSUNEMITSU  Goro YOSHIDA  Naohisa GOTO  Jiro HIROKAWA  Makoto ANDO  

     
    PAPER-Antennas

      Vol:
    E91-B No:6
      Page(s):
    1767-1772

    The center-feed in a single-layer slotted waveguide array[1]-[3] is one of the key components in polarization division duplex (PDD) wireless systems. Two center-feed arrays with orthogonal polarization and boresight beams are orthogonally arranged side-by-side for transmission and reception, simultaneously. Each antenna has extremely high XPD (almost 50 dB in measurement) and a very high isolation (over 80 dB in measurement) between two arrays is observed provided the symmetry of slot arrangement is preserved [4]. Unfortunately, the area blocked by the center feed causes high sidelobe levels. This paper proposes the ridged cross-junction multiple-way power divider for realizing blockage reduction and symmetrical slot arrangement at the same time.

  • The Nitech-NAIST HMM-Based Speech Synthesis System for the Blizzard Challenge 2006

    Heiga ZEN  Tomoki TODA  Keiichi TOKUDA  

     
    PAPER-Speech and Hearing

      Vol:
    E91-D No:6
      Page(s):
    1764-1773

    We describe a statistical parametric speech synthesis system developed by a joint group from the Nagoya Institute of Technology (Nitech) and the Nara Institute of Science and Technology (NAIST) for the annual open evaluation of text-to-speech synthesis systems named Blizzard Challenge 2006. To improve our 2005 system (Nitech-HTS 2005), we investigated new features such as mel-generalized cepstrum-based line spectral pairs (MGC-LSPs), maximum likelihood linear transform (MLLT), and a full covariance global variance (GV) probability density function (pdf). A combination of mel-cepstral coefficients, MLLT, and full covariance GV pdf scored highest in subjective listening tests, and the 2006 system performed significantly better than the 2005 system. The Blizzard Challenge 2006 evaluations show that Nitech-NAIST-HTS 2006 is competitive even when working with relatively large speech databases.

  • Control of Speed and Power in a Humanoid Robot Arm Using Pneumatic Actuators for Human-Robot Coexisting Environment

    Kiyoshi HOSHINO  

     
    PAPER-Interface Design

      Vol:
    E91-D No:6
      Page(s):
    1693-1699

    A new type of humanoid robot arm which can coexist and be interactive with human beings are looked for. For the purpose of implementation of human smooth and fast movement to a pneumatic robot, the author used a humanoid robot arm with pneumatic agonist-antagonist actuators as endoskeletons which has control mechanism in the stiffness of each joint, and the controllability was experimentally discussed. Using Kitamori 's method to experimentally decide the control gains and using I-PD controller, three joints of the humanoid robot arm were experimentally controlled. The damping control algorithm was also adopted to the wrist joint, to modify the speed in accordance with the power. The results showed that the controllability to step-wise input was less than one degree in error to follow the target angles, and the time constant was less than one second. The simultaneous input of command to three joints was brought about the overshoot of about ten percent increase in error. The humanoid robot arm can generate the calligraphic motions, moving quickly at some times but slowly at other times, or particularly softly on some occasions but stiffly on other occasions at high accuracy.

  • Stress Effect Analysis for PD SOI pMOSFETs with Undoped-Si0.88Ge0.12 Heterostructure Channel

    Sang-Sik CHOI  A-Ram CHOI  Jae-Yeon KIM  Jeon-Wook YANG  Yong-Woo HWANG  Tae-Hyun HAN  Deok Ho CHO  Kyu-Hwan SHIM  

     
    PAPER

      Vol:
    E91-C No:5
      Page(s):
    716-720

    The stress effect of SiGe p-type metal oxide semiconductor field effect transistors (MOSFETs) has been investigated to compare their properties associated with the Si0.88Ge0.12/Si epi channels grown on the Si bulk and partially depleted silicon on insulator (PD SOI) substrates. The stress-induced changes in the subthreshold slope and the drain induced barrier lowering were observed small in the SiGe PD SOI in comparison to in the SiGe bulk. Likewise the threshold voltage shift monitored as a function of hot carrier stress time presented excellent stability than in the SiGe PD SOI. Therefore, simply in terms of dc properties, the SiGe PD SOI looks more immune from electrical stresses than the SiGe bulk. However, the 1/f noise properties revealed that the hot carrier stress could introduce lots of generation-recombination noise sources in the SiGe PD SOI. The quality control of oxide-silicon in SOI structures is essential to minimize a possible surge of 1/f noise level due to the hot carrier injection. In order to improve dc and rf performance simultaneously, it is very important to grow the SiGe channels on high quality SOI substrates.

  • Co-modeling, Experimental Verification, and Analysis of Chip-Package Hierarchical Power Distribution Network

    Hyunjeong PARK  Hyungsoo KIM  Jun So PAK  Changwook YOON  Kyoungchoul KOO  Joungho KIM  

     
    PAPER-Electromagnetic Theory

      Vol:
    E91-C No:4
      Page(s):
    595-606

    In this paper, we present and verify a new chip-package co-modeling and simulation approach for a low-noise chip-package hierarchical power distribution network (PDN) design. It is based on a hierarchical modeling to combine distributed circuit models at both chip-level PDN and package-level PDN. In particular, it includes all on- and off-chip parasitic circuit elements in the hierarchical PDN with a special consideration on on-chip decoupling capacitor design and placement inside chip. The proposed hierarchical PDN model was successfully validated with good correlations and subsequent analysis to a series of Z11 and Z21 PDN impedance measurements with a frequency range from 1 MHz to 3 GHz. Using the proposed model, we can analyze and estimate the performance of the chip-package hierarchical PDN as well as can predict the effect of high frequency electromagnetic interactions between the chip-level PDN and the package-level PDN. Furthermore, we can precisely anticipate PDN resonance frequencies, noise generation sources, and noise propagation paths through the multiple levels in the hierarchical PDN.

  • Wave Absorber with Fine Weatherability for Improving ETC Environment

    Yu MIURA   Kouta MATSUMOTO   Osamu OKADA  Osamu HASHIMOTO  

     
    LETTER-Electromagnetic Theory

      Vol:
    E91-C No:3
      Page(s):
    385-388

    Wave absorber of rubber sheet containing natural rubber and EPDM is designed, fabricated and measured for improving ETC environment. As a result, proposed absorption material has fine weatherability and wave absorption satisfied with ETC standard can be realized theoretically before and after the weatherability test if the thickness of absorber is fabricated at the ranging from 2.26 mm to 2.52 mm. Moreover, absorber sheet sample based on theoretical values is fabricated and are measured. As a result, 20 dB or more is also confirmed at the incident angle ranging from 5 to 55 degrees experimentally. Therefore, the wave absorber with fine weatherability being satisfied with ETC standard can be realized.

  • Provably Secure Multisignatures in Formal Security Model and Their Optimality

    Yuichi KOMANO  Kazuo OHTA  Atsushi SHIMBO  Shinichi KAWAMURA  

     
    PAPER-Signatures

      Vol:
    E91-A No:1
      Page(s):
    107-118

    We first model the formal security model of multisignature scheme following that of group signature scheme. Second, we prove that the following three probabilistic multisignature schemes based on a trapdoor permutation have tight security; PFDH (probabilistic full domain hash) based multisignature scheme (PFDH-MSS), PSS (probabilistic signature scheme) based multisignature scheme (PSS-MSS), and short signature PSS based multisignature scheme (S-PSS-MSS). Third, we give an optimal proof (general result) for multisignature schemes, which derives the lower bound for the length of random salt. We also estimate the upper bound for the length in each scheme and derive the optimal length of a random salt. Two of the schemes are promising in terms of security tightness and optimal signature length. In appendix, we describe a multisignature scheme using the claw-free permutation and discuss its security.

  • Look-Ahead Dynamic Threshold Voltage Control Scheme for Improving Write Margin of SOI-7T-SRAM

    Masaaki IIJIMA  Kayoko SETO  Masahiro NUMA  Akira TADA  Takashi IPPOSHI  

     
    LETTER-Memory Design and Test

      Vol:
    E90-A No:12
      Page(s):
    2691-2694

    Instability of SRAM memory cells derived from aggressive technology scaling has been recently one of the most significant issues. Although a 7T-SRAM cell with an area-tolerable separated read port improves read margins even at sub-1V, it unfortunately results in degradation of write margins. In order to assist the write operation, we address a new memory cell employing a look-ahead body-bias which dynamically controls the threshold voltage. Simulation results have shown improvement in both the write margins and access time without increasing the leakage power derived from the body-bias.

  • A Parallel Algorithm for NMNF Problems with a Large Number of Capacity Constraints

    Shieh-Shing LIN  

     
    PAPER-Numerical Analysis and Optimization

      Vol:
    E90-A No:12
      Page(s):
    2884-2890

    In this paper, we propose a converting technique based method to solve nonlinear multi-commodity network flow (NMNF) problems with a large number of capacity constraints and discuss the associated implementation. We have combined this method with a successive quadratic programming (SQP) method and a parallel dual-type (PDt) method possessing decomposition effects. We have tested our method in solving a kind of lattice-type network system examples of NMNF problems. The simulation results show that the proposed algorithm is efficient for solving NMNF problems and successfully handles a large number of coupling capacity constraints. Furthermore, the computational efficiency of the proposed algorithm is more significant while the numbers of capacity constraints are increased.

  • Optical Wireless Communications and Autonomous Beam Control Moving User Terminal

    Charoen TANGTRONGBENCHASIL  Yoichi HAMADA  Toshihiro KATO  Koji NONAKA  

     
    PAPER-Optical Wireless Communications

      Vol:
    E90-B No:11
      Page(s):
    3224-3231

    Optical wireless communications is a research topic of extreme interest since it offers high data rate (Gbps data rate), security, and RF interference immunity. However, optical wireless communications places severe restrictions on the communications paths; they must be direct beam connections. To increase the number of users and link robustness, optical wireless communications must be able to operate even when obstacles are placed between transmitters and receivers, so optical micro-cell (OMC) with autonomous beam control can overcome link robustness. In addition, OMC based optical wireless communication yields compact systems. This paper presents the design, an implementation, and a demonstration of a 114 Mbps autonomous beam control optical wireless communication system based on an OMC technique. The robust posture control results optimum downlink alignment and good eye diagram of data transmission.

  • An Enhanced Simple-Adaptive Link State Update Algorithm for QoS Routing

    Seung-Hyuk CHOI  Min Young CHUNG  Mijeong YANG  Taeil KIM  Jaehyung PARK  

     
    PAPER-Network

      Vol:
    E90-B No:11
      Page(s):
    3117-3123

    In order to find paths guaranteed by Quality of Service (QoS), the link state database (LSDB), containing QoS constraint information, and residing in routers, needs to be well managed. However, there is a trade-off between the exact reflection of the current link status and the update cost to calculate and maintain this data. In order to perfectly reflect the current link state, each router immediately notifies its neighbors whenever link state information changes. However, this may degrade the performance of the router. On the other hand, if current link state information is not updated routinely, route setup requests may be rejected because of the discrepancy between the current link state information and the previously updated link state information in the LSDB. Therefore, we need link state update (LSU) algorithms making it possible to appropriately update the LSDB. In addition, to facilitate implementation, they also should have low-complexity and must be adaptive under the variation of network conditions. In this paper, we propose an enhanced simple-adaptive (ESA) LSU algorithm, to reduce the generation of LSU messages while maintaining simplicity and adaptivity. The performance of this algorithm is compared with five existing algorithms by rigorous simulations. The comparision shows that the ESU algorithm can adapt to changes in network conditions and its performance is superior to existing LSU algorithms.

  • An Initial Assignment Method for Tasks Assignment and Routing Problem of Autonomous Distributed AGVs

    Yusuke MORIHIRO  Toshiyuki MIYAMOTO  Sadatoshi KUMAGAI  

     
    PAPER

      Vol:
    E90-A No:11
      Page(s):
    2465-2471

    This paper discusses an on-line Tasks Assignment and Routing Problem (TARP) for Autonomous Transportation Systems (ATSs) in manufacturing systems. The TARP results in a constrained version of the Pickup and Delivery Problem with Time Windows (PDPTW). As an approach to this problem, a cooperative algorithm with autonomous distributed agents has been proposed. The algorithm is able to plan deadlock-free routes even though the buffer capacity is less, but includes reformability at the point that computation time of that case increases drastically. This paper proposes an initial task assignment method to reduce computation time on planning routes. Results of computational experiments show effectiveness of the proposed method.

121-140hit(276hit)