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  • Optimized Median Lifting Scheme for Lossy Image Compression

    Do QUAN  Yo-Sung HO  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E94-D No:3
      Page(s):
    721-724

    In JPEG2000, the Cohen-Daubechies-Feauveau (CDF) 9/7-tap wavelet filter was implemented by using the conventional lifting scheme. However, the filter coefficients remain complex, and the conventional lifting scheme disregards image edges in the coding process. In order to solve these issues, we propose a lifting scheme in two steps. In the first step, we select the appropriate filter coefficients; in the second step, we employ a median operator to regard image edges. Experimental results show that the peak signal-to-noise ratio (PSNR) value of the proposed lifting scheme is significantly improved, by up to 0.75 dB on average, compared to that of the conventional lifting scheme in the CDF 9/7-tap wavelet filter of JPEG2000.

  • Design Optimization of High-Speed and Low-Power Operational Transconductance Amplifier Using gm/ID Lookup Table Methodology

    Takayuki KONISHI  Kenji INAZU  Jun Gyu LEE  Masanori NATSUI  Shoichi MASUI  Boris MURMANN  

     
    PAPER-Electronic Circuits

      Vol:
    E94-C No:3
      Page(s):
    334-345

    We propose a design optimization flow for a high-speed and low-power operational transconductance amplifier (OTA) using a gm/ID lookup table design methodology in scaled CMOS. This methodology advantages from using gm/ID as a primary design parameter to consider all operation regions including strong, moderate, and weak inversion regions, and enables the lowest power design. SPICE-based lookup table approach is employed to optimize the operation region specified by the gm/ID with sufficient accuracy for short-channel transistors. The optimized design flow features 1) a proposal of the worst-case design scenario for specification and gm/ID lookup table generations from worst-case SPICE simulations, 2) an optimization procedure accomplished by the combination of analytical and simulation-based approaches in order to eliminate tweaking of circuit parameters, and 3) an additional use of gm/ID subplots to take second-order effects into account. A gain-boosted folded-cascode OTA for a switched capacitor circuit is adopted as a target topology to explore the effectiveness of the proposed design methodology for a circuit with complex topology. Analytical expressions of the gain-boosted folded-cascode OTA in terms of DC gain, frequency response and output noise are presented, and detailed optimization of gm/IDs as well as circuit parameters are illustrated. The optimization flow is verified for the application to a residue amplifier in a 10-bit 125 MS/s pipeline A/D converter implemented in a 0.18 µm CMOS technology. The optimized circuit satisfies the required specification for all corner simulations without additional tweaking of circuit parameters. We finally explore the possibility of applying this design methodology as a technology migration tool, and illustrate the failure analysis by comparing the differences in the gm/ID characteristics.

  • Survey of Network Coding and Its Applications Open Access

    Takahiro MATSUDA  Taku NOGUCHI  Tetsuya TAKINE  

     
    INVITED SURVEY PAPER

      Vol:
    E94-B No:3
      Page(s):
    698-717

    This survey summarizes the state-of-the-art research on network coding, mainly focusing on its applications to computer networking. Network coding generalizes traditional store-and-forward routing techniques by allowing intermediate nodes in networks to encode several received packets into a single coded packet before forwarding. Network coding was proposed in 2000, and since then, it has been studied extensively in the field of computer networking. In this survey, we first summarize linear network coding and provide a taxonomy of network coding research, i.e., the network coding design problem and network coding applications. Moreover, the latter is subdivided into throughput/capacity enhancement, robustness enhancement, network tomography, and security. We then discuss the fundamental characteristics of network coding and diverse applications of network coding in details, following the above taxonomy.

  • Layout-Driven Skewed Clock Tree Synthesis for Superconducting SFQ Circuits

    Kazuyoshi TAKAGI  Yuki ITO  Shota TAKESHIMA  Masamitsu TANAKA  Naofumi TAKAGI  

     
    PAPER

      Vol:
    E94-C No:3
      Page(s):
    288-295

    In this paper, we propose a method for layout-driven skewed clock tree synthesis for SFQ logic circuits. For a given logic circuit without a clock tree, our algorithm outputs a circuit with a synthesized clock tree and timing adjustments achieving the given clock period and a rough placement of the clocked gates. In the proposed algorithm, clocked gates are grouped into levels and the clock tree is synthesized for each level. For each level, we estimate the clock timing for all possible placements of each gate, and then we search a placement of all gates that minimizes the total number of delay elements for timing adjustment. Once the placement is obtained, we synthesize a clock tree without wire intersections. We applied the proposed method to a moderate size circuit and confirmed that clock trees satisfying given timing requirements can be synthesized automatically.

  • Post-Routing Double-Via Insertion for X-Architecture Clock Tree Yield Improvement

    Chia-Chun TSAI  Chung-Chieh KUO  Trong-Yen LEE  

     
    PAPER-VLSI Design Technology and CAD

      Vol:
    E94-A No:2
      Page(s):
    706-716

    As the VLSI manufacturing technology shrinks to 65 nm and below, reducing the yield loss induced by via failures is a critical issue in design for manufacturability (DFM). Semiconductor foundries highly recommend using the double-via insertion (DVI) method to improve yield and reliability of designs. This work applies the DVI method in the post-stage of an X-architecture clock routing for double-via insertion rate improvement. The proposed DVI-X algorithm constructs the bipartite graphs of the partitioned clock routing layout with single vias and redundant-via candidates (RVCs). Then, DVI-X applies the augmenting path approach associated with the construction of the maximal cliques to obtain the matching solution from the bipartite graphs. Experimental results on benchmarks show that DVI-X can achieve higher double-via insertion rate by 3% and less running time by 68% than existing works. Moreover, a skew tuning technique is further applied to achieve zero skew because the inserted double vias affect the clock skew.

  • A Proposition of 600 Mbps WLAN-Like System with Low-Complexity MIMO Decoder for FPGA Implementation

    Wahyul Amien SYAFEI  Yuhei NAGAO  Ryuta IMASHIOYA  Masayuki KUROSAKI  Baiko SAI  Hiroshi OCHI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E94-B No:2
      Page(s):
    491-498

    This paper deals with our works on developing a high-throughput wireless LAN using a group layered space-time (GLST) system with low-complexity MIMO decoder. It achieves the throughput of 600 Mbps for 30 meter propagation distance by utilizing 80 MHz bandwidth in the 5 GHz frequency band. Run test under channel model B of IEEE802.11TGn demonstrates its excellent performance. The register transfer level results show that the developed system is synthesized successfully and the prototyping in the target FPGA chips of Stratix II EP2S180F1508C4 gives the expected results.

  • The Precoder Design for Intrablock MMSE Equalization and Block Delay Detection with a Modified Oblique Projection Framework

    Chun-Hsien WU  

     
    LETTER-Digital Signal Processing

      Vol:
    E94-A No:2
      Page(s):
    829-832

    This letter presents a method to enable the precoder design for intrablock MMSE equalization with previously proposed oblique projection framework. The joint design of the linear transceiver with optimum block delay detection is built. Simulation results validate the proposed approach and show the superior BER performance of the optimized transceiver.

  • A Neuro Fuzzy Solution in the Design of Analog Circuits

    Pedro MIRANDA-ROMAGNOLI  Norberto HERNANDEZ-ROMERO  Juan C. SECK-TUOH-MORA  

     
    LETTER-VLSI Design Technology and CAD

      Vol:
    E94-A No:1
      Page(s):
    434-439

    A neuro fuzzy method to design analog circuits is explained, where the universe of discourse of the fuzzy system is adjusted by means of a self-organized artificial neural network. As an example of this approach, an op-amp is optimized in order to hold a predetermined aim; where the unity gain bandwidth is an objective of design, and the restrictions of open-loop gain and margin phase are treated as objectives too. Firstly, the experience of the behavior of the circuit is obtained, hence an inference system is constructed and a neural network is applied to achieve a faster convergence into a desired solution. This approach is characterized by having a simple implementation, a very natural understanding and a better performance than static methods of fuzzy optimization.

  • A Complete Solution to a Simple Case of Dynamic Observer Error Linearization: New Approach to Observer Error Linearization

    Jongwook YANG  Juhoon BACK  Jin H. SEO  

     
    LETTER-Systems and Control

      Vol:
    E94-A No:1
      Page(s):
    424-429

    In this letter, we propose a new observer error linearization approach that is called reduced-order dynamic observer error linearization (RDOEL), which is a modified version of dynamic observer error linearization (DOEL). We introduce the concepts and properties of RDOEL, and provide a complete solution to RDOEL with one integrator. Moreover, we show that it is also a complete solution to a simple case of DOEL.

  • Photomask Data Prioritization Based on VLSI Design Intent and Its Utilization for Mask Manufacturing

    Kokoro KATO  Masakazu ENDO  Tadao INOUE  Shigetoshi NAKATAKE  Masaki YAMABE  Sunao ISHIHARA  

     
    PAPER-Device and Circuit Modeling and Analysis

      Vol:
    E93-A No:12
      Page(s):
    2424-2432

    The increase in the time required for data processing, mask drawing, and inspection of photomask, has led to substantial increase in mask manufacturing cost. This has become one of the major challenges in the semiconductor industry. We have developed a data flow process for mask manufacturing in which we refer to design intent information in order to reduce TAT of mask manufacturing processes. We convert design level information "Design Intent (DI)" into priority information of mask manufacturing data known as "Mask Data Rank (MDR)" so that we can identify and sort out the importance of mask patterns from the view point of the design side. As a result, we can reduce mask writing time and mask inspection time. Our objective is to build efficient data flow conversion system from DI to MDR. In this paper we introduce the idea of MDR and the software system that we built for DI extraction. Then we show the experimental results with actual chip data. Lastly we will discuss related issues and their solutions.

  • A Multi-Performance Processor for Reducing the Energy Consumption of Real-Time Embedded Systems

    Tohru ISHIHARA  

     
    PAPER-High-Level Synthesis and System-Level Design

      Vol:
    E93-A No:12
      Page(s):
    2533-2541

    This paper proposes an energy efficient processor which can be used as a design alternative for the dynamic voltage scaling (DVS) processors in embedded system design. The processor consists of multiple PE (processing element) cores and a selective set-associative cache memory. The PE-cores have the same instruction set architecture but differ in their clock speeds and energy consumptions. Only a single PE-core is activated at a time and the other PE-cores are deactivated using clock gating and signal gating techniques. The major advantage over the DVS processors is a small overhead for changing its performance. The gate-level simulation demonstrates that our processor can change its performance within 1.5 microsecond and dissipates about 10 nano-joule while conventional DVS processors need hundreds of microseconds and dissipate a few micro-joule for the performance transition. This makes it possible to apply our multi-performance processor to many real-time systems and to perform finer grained and more sophisticated dynamic voltage control.

  • Automatic Communication Synthesis with Hardware Sharing for Multi-Processor SoC Design

    Yuki ANDO  Seiya SHIBATA  Shinya HONDA  Hiroyuki TOMIYAMA  Hiroaki TAKADA  

     
    PAPER-High-Level Synthesis and System-Level Design

      Vol:
    E93-A No:12
      Page(s):
    2509-2516

    We present a hardware sharing method for design space exploration of multi-processor embedded systems. In our prior work, we had developed a system-level design tool named SystemBuilder which automatically synthesizes target implementation of a system from a functional description. In this work, we have extended SystemBuilder so that it can automatically synthesize an area-efficient implementation which shares a hardware module among different applications. With SystemBuilder, designers only need to enable an option in order to share a hardware module. The designers, therefore, can easily explore a design space including hardware sharing in short time. A case study shows the effectiveness of the hardware sharing on design space exploration.

  • Redundant via Insertion: Removing Design Rule Conflicts and Balancing via Density

    Song CHEN  Jianwei SHEN  Wei GUO  Mei-Fang CHIANG  Takeshi YOSHIMURA  

     
    PAPER-Physical Level Design

      Vol:
    E93-A No:12
      Page(s):
    2372-2379

    The occurrence of via defects increases due to the shrinking size in integrated circuit manufacturing. Redundant via insertion is an effective and recommended method to reduce the yield loss caused by via failures. In this paper, we introduce the redundant via allocation problem for layer partition-based redundant via insertion methods [1] and solve it using the genetic algorithm. At the same time, we use a convex-cost flow model to equilibrate the via density, which is good for the via density rules. The results of layer partition-based model depend on the partition and processing order of metal layers. Furthermore, even we try all of partitions and processing orders, we might miss the optimal solutions. By introducing the redundant via allocation problem on partitioning boundaries, we can avoid the sub-optimality of the original layer-partition based method. The experimental results show that the proposed method got 12 more redundant vias inserted on average and the via density balance can be greatly improved.

  • A Survey of the Origins and Evolution of the Microwave Circuit Devices in Japan from the 1920s up until 1945

    Tosiro KOGA  

     
    INVITED SURVEY PAPER

      Vol:
    E93-A No:12
      Page(s):
    2354-2370

    We edit in this paper several archives on the research and development in the field of microwave circuit technology in Japan, that originated with the invention of Yagi-Uda antenna in 1925, together with generally unknown historical topics in the period from the 1920s up until the end of World War II. As the main subject, we investigate the origin and evolution of the Multiply Split-Anode Magnetron, and clarify that the basic magnetron technology had been established until 1939 under the direction of Yoji Ito in cooperation of expert engineers between the Naval Technical Institute (NTI) and the Nihon Musen Co., while the Cavity Magnetron was invented by Shigeru Nakajima of the Nihon Musen Co. in May 1939, and further that physical theory of the Multiply Split-Anode Cavity Magnetron Oscillation and the design theory of the Cavity Magnetron were established in collaboration between the world-known physicists and the expert engineers at the NTI Shimada Laboratory in the wartime. In addition, we clarify that Sin-itiro Tomonaga presented the Scattering Matrix representation of Microwave Circuits, and others. The development mentioned above was carried out, in strict secrecy, in an unusual wartime situation up until 1945.

  • Estimation of the Effects in the Experimental Design Using Fourier Transforms

    Yoshifumi UKITA  Toshiyasu MATSUSHIMA  Shigeichi HIRASAWA  

     
    LETTER-Information Theory

      Vol:
    E93-A No:11
      Page(s):
    2077-2082

    We propose that the model in experimental design be expressed in terms of an orthonormal system. Then, we can easily estimate the effects using Fourier transforms. We also provide the theorems with respect to the sum of squares needed in analysis of variance. Using these theorems, it is clear that we can execute the analysis of variance in this model.

  • A Structured Codebook with Various Codeword Configurations for Downlink MIMO Systems

    Hyunil KWON  Myeongcheol SHIN  Chungyong LEE  

     
    LETTER-Wireless Communication Technologies

      Vol:
    E93-B No:11
      Page(s):
    3193-3196

    A structured codebook with various codeword configurations is proposed to overcome the sum capacity limitation in a region with finite number of users. Specifically, based on multi-user MIMO platform with a codebook of multiple orthonormal sets, called as per user unitary rate control (PU2RC), we diversify the codeword configuration of each orthonormal set and expand the corresponding codeword configuration. Numerical experiments with respect to several system parameters, such as user density and received signal to noise ratio, show that the proposed codebook offers throughput gains over the conventional system in a small to moderate number of user region.

  • Improved Indoor Location Estimation Using Fluorescent Light Communication System with a Nine-Channel Receiver

    Xiaohan LIU  Hideo MAKINO  Kenichi MASE  

     
    PAPER

      Vol:
    E93-B No:11
      Page(s):
    2936-2944

    The need for efficient movement and precise location of robots in intelligent robot control systems within complex buildings is becoming increasingly important. This paper proposes an indoor positioning and communication platform using Fluorescent Light Communication (FLC) employing a newly developed nine-channel receiver, and discusses a new location estimation method using FLC, that involves a simulation model and coordinate calculation formulae. A series of experiments is performed. Distance errors of less than 25 cm are achieved. The enhanced FLC system yields benefits such as greater precision and ease of use.

  • Heuristic Designs of SAD Algorithm for a Platform-Based Vision System

    JunSeong KIM  Jongsu YI  

     
    LETTER-Image Recognition, Computer Vision

      Vol:
    E93-D No:11
      Page(s):
    3140-3143

    Vision sensors provide rich sources of information, but sensing images and processing them in real time would be a challenging task. This paper introduces a vision system using SoCBase platform and presents heuristic designs of SAD correlation algorithm as a component of the vision system. Simulation results show that the vision system is suitable for real-time applications and that the heuristic designs of SAD algorithm are worth utilizing since they save a considerable amount of space with little sacrificing in quality.

  • A Generalized Construction of Optimal Zero-Correlation Zone Sequence Set from a Perfect Sequence Pair

    Takafumi HAYASHI  Shinya MATSUFUJI  

     
    LETTER-Sequences

      Vol:
    E93-A No:11
      Page(s):
    2337-2344

    The present paper introduces a new approach to the construction of a sequence set with a zero-correlation zone (ZCZ). This sequence set is referred to as a ZCZ sequence set. The proposed sequence construction generates a ZCZ sequence set from a perfect sequence pair or a single perfect sequence. The proposed method can generate an optimal ZCZ sequence set, the member size of which reaches the theoretical bound.

  • A Cross Layer Perceptual Speech Quality Based Wireless VoIP Service

    Tein-Yaw CHUNG  Yung-Mu CHEN  Liang-Yi HUANG  

     
    PAPER

      Vol:
    E93-A No:11
      Page(s):
    2153-2162

    This paper proposes a cross layer wireless VoIP service which integrates an Adaptive QoS Playout (AQP) algorithm, E-model, Stream Control Transmission Protocol (SCTP), IEEE 802.21 Media Independent Handover (MIH) middleware and two user motion detection services. The proposed AQP algorithm integrates the effect of playout control and lost packet retransmission based on the E-model. Besides, by using the partial reliable transmission service from SCTP and the handoff notification from MIH services in a cross layer manner, AQP can reduce the lateness loss rate and improve speech quality under high frame error rates. In the simulations, the performance of AQP is compared with a fixed playout algorithm and four adaptive playout strategies. The simulation results show that the lateness loss rate of AQP is 2% lower than that of existing playout algorithms and the R-factor is 16% higher than the compared algorithms when a network has 50 ms wired propagation delay and 2.5% frame error rate.

261-280hit(888hit)