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[Keyword] ATI(18690hit)

5401-5420hit(18690hit)

  • A Proper Phase Shift in Multiple Linear Optical Teleportation

    Kazuto OSHIMA  

     
    LETTER-Fundamentals of Information Systems

      Vol:
    E96-D No:10
      Page(s):
    2266-2267

    In the Knill-Laflamme-Milburn (KLM) scheme, quantum teleportation is nearly deterministically carried out with linear optics. To reconstruct an original quantum state, however, a phase shift is required for an output state. We exhibit a proper phase shift to complete quantum teleportation.

  • Online Sparse Volterra System Identification Using Projections onto Weighted l1 Balls

    Tae-Ho JUNG  Jung-Hee KIM  Joon-Hyuk CHANG  Sang Won NAM  

     
    PAPER

      Vol:
    E96-A No:10
      Page(s):
    1980-1983

    In this paper, online sparse Volterra system identification is proposed. For that purpose, the conventional adaptive projection-based algorithm with weighted l1 balls (APWL1) is revisited for nonlinear system identification, whereby the linear-in-parameters nature of Volterra systems is utilized. Compared with sparsity-aware recursive least squares (RLS) based algorithms, requiring higher computational complexity and showing faster convergence and lower steady-state error due to their long memory in time-invariant cases, the proposed approach yields better tracking capability in time-varying cases due to short-term data dependence in updating the weight. Also, when N is the number of sparse Volterra kernels and q is the number of input vectors involved to update the weight, the proposed algorithm requires O(qN) multiplication complexity and O(Nlog 2N) sorting-operation complexity. Furthermore, sparsity-aware least mean-squares and affine projection based algorithms are also tested.

  • Location-Based Key Management Structure for Secure Group Communication in Wireless Sensor Networks

    Jin Myoung KIM  Tae Ho CHO  

     
    PAPER-Fundamental Theories for Communications

      Vol:
    E96-B No:9
      Page(s):
    2183-2189

    Many applications of wireless sensor networks (WSNs) require secure communication. The tree-based key management scheme, which is a symmetric key scheme, provides backward and forward secrecy. The sensor nodes in the communication group share a secret key for encrypting messages. When the sensor nodes are added to or evicted from the group, the group key has to be updated by sending rekeying messages. In this paper, we propose a method of key tree structure (KTS) generation by considering the addition and eviction ratio of sensor nodes to reduce the number of rekeying messages, which is influenced by the structure of the tree. For this, we define an extension of an existing tree structure such as a binary or ternary tree and generate KTS using an A* algorithm. To reduce the energy consumed by the message transmission, we also exploit genetic algorithm (GA) to build a secure communication group by considering the KTS. In the paper, we show the effectiveness of the proposed method compared with the existing structure via the simulation in terms of memory usage, the number of rekeying messages and energy consumption.

  • Detection of the Number of Signals with Fewer Sensors than Sources

    Masashi TSUJI  Kenta UMEBAYASHI  Yasuo SUZUKI  

     
    PAPER-Antennas and Propagation

      Vol:
    E96-B No:9
      Page(s):
    2235-2243

    In this paper, a method is introduced that can detect the number of incident signals (NIS) even there are fewer antennas than NIS. Previous works on NIS detection methods assumed that the number of antennas always exceeded NIS. In the DOA estimation field, the DOA estimation is possible, even if NIS exceeds the number of antennas, by extending the degrees of freedom of array (DOFA) using a modified array configuration, such as a nested array (NA). The information of NIS is required in advance to accurately estimate DOA, however, it has not been investigated deeply when NIS is larger than the number of antennas. In this paper, a NIS detection method based on the DOFA extending process using NA is proposed. One of the important issues in NIS detection is the detection metric. As one of the simple metrics, the ratio of adjacent eigenvalues (RAE) has been used. However, the direct application of RAE may not achieve adequate NIS detection performance. Therefore, we propose a metric based on the modified ratio of adjacent eigenvalues (MRAE) avoids the issue of RAE. Numerical results show that the metric based on MRAE can achieve proper NIS detection performance even if NIS is larger than the number of antennas.

  • Open-Fault Resilient Multiple-Valued Codes for Reliable Asynchronous Global Communication Links

    Naoya ONIZAWA  Atsushi MATSUMOTO  Takahiro HANYU  

     
    PAPER

      Vol:
    E96-D No:9
      Page(s):
    1952-1961

    This paper introduces open-wire fault-resilient multiple-valued codes for reliable asynchronous point-to-point global communication links. In the proposed encoding, two communication modules assign complementary codewords that change between two valid states without an open-wire fault. Under an open-wire fault, at each module, the codewords don't reach to one of the two valid states and remains as “invalid” states. The detection of the invalid states makes it possible to stop sending wrong codewords caused by an open-wire fault. The detectability of the open-wire fault based on the proposed encoding is proven for m-of-n codes. The proposed code used in the multiple-valued asynchronous global communication link is capable of detecting a single open-wire fault with 3.08-times higher coding efficiency compared with a conventional multiple-valued code used in a triple-modular redundancy (TMR) link that detects an open-wire fault under the same dynamic range of logical values.

  • A Method for Minimizing Clock Skew Fluctuations Caused by Interconnect Process Variations

    Susumu KOBAYASHI  Fumihiro MINAMI  

     
    PAPER

      Vol:
    E96-D No:9
      Page(s):
    1980-1985

    As the LSI process technology advances and the gate size becomes smaller, the signal delay on interconnect becomes a significant factor in the signal path delay. Also, as the size of interconnect structure becomes smaller, the interconnect process variations have become one of the dominant factors which influence the signal delay and thus clock skew. Therefore, controlling the influence of interconnect process variations on clock skew is a crucial issue in the advanced process technologies. In this paper, we propose a method for minimizing clock skew fluctuations caused by interconnect process variations. The proposed method identifies the suitable balance of clock buffer size and wire length in order to minimize the clock skew fluctuations caused by the interconnect process variations. Experimental results on test circuits of 28nm process technology show that the proposed method reduces the clock skew fluctuations by 30-92% compared to the conventional method.

  • A Novel Network Modeling and Evaluation Approach for Security Vulnerability Quantification in Substation Automation Systems

    Jongbin KO  Seokjun LEE  Yong-hun LIM  Seong-ho JU  Taeshik SHON  

     
    LETTER

      Vol:
    E96-D No:9
      Page(s):
    2021-2025

    With the proliferation of smart grids and the construction of various electric IT systems and networks, a next-generation substation automation system (SAS) based on IEC 61850 has been agreed upon as a core element of smart grids. However, research on security vulnerability analysis and quantification for automated substations is still in the preliminary phase. In particular, it is not suitable to apply existing security vulnerability quantification approaches to IEC 61850-based SAS because of its heterogeneous characteristics. In this paper, we propose an IEC 61850-based SAS network modeling and evaluation approach for security vulnerability quantification. The proposed approach uses network-level and device groupings to categorize the characteristic of the SAS. In addition, novel attack scenarios are proposed through a zoning scheme to evaluate the network model. Finally, an MTTC (Mean Time-to-Compromise) scheme is used to verify the proposed network model using a sample attack scenario.

  • On the Cross-Correlation of a p-Ary m-Sequence and Its Decimated Sequences by d=(pn+1)/(pk+1)+(pn-1)/2

    Sung-Tai CHOI  Ji-Youp KIM  Jong-Seon NO  

     
    PAPER-Fundamental Theories for Communications

      Vol:
    E96-B No:9
      Page(s):
    2190-2197

    In this paper, for an odd prime p such that p≡3 mod 4, odd n, and d=(pn+1)/(pk+1)+(pn-1)/2 with k|n, the value distribution of the exponential sum S(a,b) is calculated as a and b run through $mathbb{F}_{p^n}$. The sequence family $mathcal{G}$ in which each sequence has the period of N=pn-1 is also constructed. The family size of $mathcal{G}$ is pn and the correlation magnitude is roughly upper bounded by $(p^k+1)sqrt{N}/2$. The weight distribution of the relevant cyclic code C over $mathbb{F}_p$ with the length N and the dimension ${ m dim}_{mathbb{F}_p}mathcal{C}=2n$ is also derived.

  • Simplification of Service Functions Resulting from Growth in Scale of Networks

    Nagao OGINO  Hideyuki KOTO  Hajime NAKAMURA  Shigehiro ANO  

     
    PAPER-Network

      Vol:
    E96-B No:9
      Page(s):
    2224-2234

    As a network evolves following initial deployment, its service functions remain diversified through the openness of the network functions. This indicates that appropriate simplification of the service functions is essential if the evolving network is to achieve the required scalability of service processing and service management. While the screening of service functions is basically performed by network users and the market, several service functions will be automatically simplified based on the growth of the evolving network. This paper verifies the simplification of service functions resulting from the evolution of the network itself. First, the principles that serve as the basis for simplifying the service functions are explained using several practical examples. Next, a simulation model is proposed to verify the simplification of service functions in terms of the priority control function for path routing and load balancing among multiple paths. From the results of the simulation, this study clarifies that the anticipated simplification of service functions is actually realizable and the service performance requirements can be reduced as the network evolves after deployment. When the simplification of service functions can improve network quality, it accelerates the evolution of the network and increases the operator's revenue.

  • Synchronization of Two Different Unified Chaotic Systems with Unknown Mismatched Parameters via Sum of Squares Method

    Cheol-Joong KIM  Dongkyoung CHWA  

     
    PAPER-Nonlinear Problems

      Vol:
    E96-A No:9
      Page(s):
    1840-1847

    This paper proposes the synchronization control method for two different unified chaotic systems with unknown mismatched parameters using sum of squares method. Previously, feedback-linearizing and stabilization terms were used in the controller for the synchronization problem. However, they used just a constant matrix as a stabilization control gain, whose performance is shown to be valid only for a linear model. Thus, we propose the novel control method for the synchronization of the two different unified chaotic systems with unknown mismatched parameters via sum of squares method. We design the stabilization control input which is of the polynomial form by sum of squares method and also the adaptive law for the estimation of the unknown mismatched parameter between the master and slave systems. Since we can use the polynomial control input which is dependent on the system states as the stabilization controller, the proposed method can have better performance than the previous methods. Numerical simulations for both uni-directional and bi-directional chaotic systems show the validity and advantage of the proposed method.

  • Locality-Constrained Multi-Task Joint Sparse Representation for Image Classification

    Lihua GUO  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E96-D No:9
      Page(s):
    2177-2181

    In the image classification applications, the test sample with multiple man-handcrafted descriptions can be sparsely represented by a few training subjects. Our paper is motivated by the success of multi-task joint sparse representation (MTJSR), and considers that the different modalities of features not only have the constraint of joint sparsity across different tasks, but also have the constraint of local manifold structure across different features. We introduce the constraint of local manifold structure into the MTJSR framework, and propose the Locality-constrained multi-task joint sparse representation method (LC-MTJSR). During the optimization of the formulated objective, the stochastic gradient descent method is used to guarantee fast convergence rate, which is essential for large-scale image categorization. Experiments on several challenging object classification datasets show that our proposed algorithm is better than the MTJSR, and is competitive with the state-of-the-art multiple kernel learning methods.

  • Frame Synchronization for Depth-Based 3D Video Using Edge Coherence

    Youngsoo PARK  Taewon KIM  Namho HUR  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E96-D No:9
      Page(s):
    2166-2169

    A method of frame synchronization between the color video and depth-map video for depth based 3D video using edge coherence is proposed. We find a synchronized pair of frames using edge coherence by computing the maximum number of overlapped edge pixels between the color video and depth-map video in regions of temporal frame difference. The experimental results show that the proposed method can be used for synchronization of depth-based 3D video and that it is robust against Gaussian noise with σ = less than 30 and video compression by H.264/AVC with QP = less than 44.

  • Analysis and Enhancement of an Optimized Gateway-Oriented Password-Based Authenticated Key Exchange Protocol

    Fushan WEI  Zhenfeng ZHANG  Chuangui MA  

     
    PAPER-Cryptography and Information Security

      Vol:
    E96-A No:9
      Page(s):
    1864-1871

    In this paper, we point out that Yoon et al.'s gateway-oriented password-based authenticated key exchange (GPAKE) protocol is inefficiently and incorrectly designed to overcome the undetectable on-line dictionary attack. To remedy these problems, we propose a new GPAKE protocol and prove its security in the random oracle model. Performance analysis demonstrates that our protocol is more secure and efficient than previous protocols.

  • Improved Transmit and Detection Scheme for Hybrid STBC in MIMO-OFDM Systems

    Eui-Young LEE  Hyoung-Kyu SONG  

     
    LETTER-Information Network

      Vol:
    E96-D No:9
      Page(s):
    2131-2134

    The conventional hybrid STBC schemes can achieve less BER performance for STBC detection schemes than conventional STBC schemes since SM symbols interfere with STBC symbols. Therefore, this letter proposes the improved scheme for hybrid STBC systems. STBC and SM schemes are combined for the hybrid space-time block code system. Our approach effectively obtains both diversity gain and spectral efficiency gain. The proposed scheme offers improved BER performance since it uses iterative detection. Moreover, it increases the data rate effectively with a little performance loss.

  • Experimental Analysis of Arc Waveform Affected by Holder Temperature Change at Slowly Separation of Silver-Tin Dioxide Contacts

    Yoshiki KAYANO  Kazuaki MIYANAGA  Hiroshi INOUE  

     
    PAPER

      Vol:
    E96-C No:9
      Page(s):
    1110-1118

    Arc discharge at breaking electrical contact is considered as a main source of not only degradation of the electrical property but also an undesired electromagnetic (EM) noise. In order to clarify the effect of holder temperature on the bridge and arc-duration, opening-waveforms at slowly separating silver-tin dioxide contact with different holder temperature are measured and discussed experimentally in this paper. Firstly, as opening-waveforms, the contact voltage, the contact current and the movement of moving contact related to the gap length are measured simultaneously. Secondly, the relationship between temperature of the holder and duration of the arc was quantified experimentally. It was revealed that as the initial temperature of the holder becomes higher, arc-duration becomes slightly longer. More importantly, the holder temperature dependencies of percentage of each-phase (metallic and gaseous-phases) are different with different closed-current.

  • A Test Compaction Oriented Don't Care Identification Method Based on X-bit Distribution

    Hiroshi YAMAZAKI  Motohiro WAKAZONO  Toshinori HOSOKAWA  Masayoshi YOSHIMURA  

     
    PAPER

      Vol:
    E96-D No:9
      Page(s):
    1994-2002

    In recent years, the growing density and complexity of VLSIs have led to an increase in the numbers of test patterns and fault models. Test patterns used in VLSI testing are required to provide high quality and low cost. Don't care (X) identification techniques and X-filling techniques are methods to satisfy these requirements. However, conventional X-identification techniques are less effective for application-specific fields such as test compaction because the X-bits concentrate on particular primary inputs and pseudo primary inputs. In this paper, we propose a don't care identification method for test compaction. The experimental results for ITC'99 and ISCAS'89 benchmark circuits show that a given test set can be efficiently compacted by the proposed method.

  • Generation of Controllable Heating Patterns for Interstitial Microwave Hyperthermia by Coaxial-Dipole Antennas

    Kazuyuki SAITO  Masaharu TAKAHASHI  Koichi ITO  

     
    PAPER-Electromagnetic Theory

      Vol:
    E96-C No:9
      Page(s):
    1178-1183

    Hyperthermia is one of the modalities for cancer treatment, utilizing the difference of thermal sensitivity between tumor and normal tissue. Interstitial microwave hyperthermia is one of the heating schemes and it is applied to a localized tumor. In the treatments, heating pattern control around antennas are important, especially for the treatment in and around critical organs. This paper introduces a coaxial-dipole antenna, which is one of the thin microwave antennas and can generate a controllable heating pattern. Moreover, generations of an arbitrary shape heating patterns by an array applicator composed of four coaxial-dipole antennas are described.

  • Identification of Smallest Unacceptable Combinations of Simultaneous Component Failures in Information Systems

    Kumiko TADANO  Jianwen XIANG  Fumio MACHIDA  Yoshiharu MAENO  

     
    PAPER

      Vol:
    E96-D No:9
      Page(s):
    1941-1951

    Large-scale disasters may cause simultaneous failures of many components in information systems. In the design for disaster recovery, operational procedures to recover from simultaneous component failures need to be determined so as to satisfy the time-to-recovery objective within the limited budget. For this purpose, it is beneficial to identify the smallest unacceptable combination of component failures (SUCCF) which exceeds the acceptable cost for recovering the system. This allows us to know the limitation of the recovery capability of the designed recovery operation procedure. In this paper, we propose a technique to identify the SUCCF by predicting the required cost for recovery from each combination of component failures with and without two-person cross-check of execution of recovery operations. We synthesize analytic models from the description of recovery operation procedure in the form of SysML Activity Diagram, and solve the models to predict the time-to-recovery and the cost. An example recovery operation procedure for a commercial database management system is used to demonstrate the proposed technique.

  • Low-Overhead Fault-Secure Parallel Prefix Adder by Carry-Bit Duplication

    Nobutaka KITO  Naofumi TAKAGI  

     
    PAPER

      Vol:
    E96-D No:9
      Page(s):
    1962-1970

    We propose a low-overhead fault-secure parallel prefix adder. We duplicate carry bits for checking purposes. Only one half of normal carry bits are compared with the corresponding redundant carry bits, and the hardware overhead of the adder is low. For concurrent error detection, we also predict the parity of the result. The adder uses parity-based error detection and it has high compatibility with systems that have parity-based error detection. We can implement various fault-secure parallel prefix adders such as Sklansky adder, Brent-Kung adder, Han-Carlson adder, and Kogge-Stone adder. The area overhead of the proposed adder is about 15% lower than that of a previously proposed adder that compares all the carry bits.

  • Development of RFID Antenna for Detection of Urination

    Hiromasa NAKAJIMA  Masaharu TAKAHASHI  Kazuyuki SAITO  Koichi ITO  

     
    PAPER-Antennas and Propagation

      Vol:
    E96-B No:9
      Page(s):
    2244-2250

    This paper introduces a radio frequency identification (RFID) tag for urination detection. The proposed tag is embedded into paper diapers in order to detect the patient's urination immediately. For this tag, we designed an RFID tag antenna at 950MHz, which matches the impedance of the associated integrated circuit (IC) chip. In addition, we calculate the antenna characteristics and measure the reflection coefficient (S11) and radiation pattern of the antenna. The results show that this system can be used to detect urination.

5401-5420hit(18690hit)