The search functionality is under construction.
The search functionality is under construction.

Keyword Search Result

[Keyword] Ti(30728hit)

20521-20540hit(30728hit)

  • Real-Time Frame-Layer Rate Control for Low Bit Rate Video over the Internet

    Yoon KIM  Jae-Young PYUN  Jae-Hwan JEONG  Sung-Jea KO  

     
    PAPER-Multimedia Communication

      Vol:
    E87-B No:3
      Page(s):
    598-604

    A real-time frame-layer rate control algorithm using sliding window method is proposed for low bit rate video coding over the Internet. The proposed rate control method performs bit allocation at the frame level to minimize the average distortion over an entire sequence as well as variations in distortion between frames. A new frame-layer rate-distortion model is derived, and a non-iterative optimization method is used for low computational complexity. In order to reduce the quality fluctuation, we use a sliding window scheme which does not require the pre-analysis process. Therefore, the proposed algorithm does not produce time delay from encoding, and is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better visual and PSNR performance than the existing TMN8 rate control method.

  • Geometrically Invariant Watermarking Based on Gravity Center

    Ke DING  Chen HE  Ling-ge JIANG  Hong-xia WANG  

     
    LETTER-Information Security

      Vol:
    E87-A No:2
      Page(s):
    513-515

    A novel geometrically invariant watermarking scheme based on gravity center is presented which treating the geometrically invariant gravity centers of host image and its supplement image as reference points. Thus watermark synchronization is obtained. Simulation results show the effectiveness of our scheme to the geometrical distortion including rotation and/or scaling.

  • Investigation of Single Monolayer Formation of the Evaporated Liquid Crystalline Molecules by the Surface Potential Measurement

    Takaaki MANAKA  Hajime HIGA  Dai NAKAMURA  Dai TAGUCHI  Mitsumasa IWAMOTO  

     
    LETTER-Nano-interface Controlled Electronic Devices

      Vol:
    E87-C No:2
      Page(s):
    183-184

    The formation of single monolayer of liquid crystalline molecules, 4-n-pentyl-4-cyanobiphenyl (5CB), deposited by the evaporation method in the air, was confirmed with the surface potential measurement. The surface potential increased with the time of evaporation, and the 3- or 4-minute evaporation at a source temperature of 110 gave the saturated potential, indicating the formation of single monolayer. Single monolayer formation was also supported by the comparison of the UV-visible absorption for evaporated film with LB monolayer. Positive potentials were built at the surface, indicating that CN group faces the substrate.

  • Deterministic Task Scheduling for Embedded Real-Time Operating Systems

    Sun-Jin OH  Jeong-Nyeo KIM  Yeong-Rak SEONG  Cheol-Hoon LEE  

     
    LETTER-Software Systems

      Vol:
    E87-D No:2
      Page(s):
    472-474

    In recent years, there has been a rapid and widespread proliferation of non-traditional embedded computing platforms such as digital camcorders, cellular phones, and portable medical devices. As applications become increasingly sophisticated and processing power increases, the application designer has to rely on the services provided by the real-time operating systems (RTOSs). These RTOSs must not only provide predictable services but must also be efficient and small in size. Kernel services should also be deterministic by specifying how long each service call will take to execute. Having this information allows the application designers to better plan their real-time application software so as not to miss the deadline of each task. In this paper, we propose a generalized deterministic scheduling algorithm that makes the task scheduling time constant irrespective of the number of tasks created in an application. The proposed algorithm eliminates the restriction on the maximum number of task priorities imposed on the existing ones, without additional memory overhead.

  • New Classes of Bent Functions and Generalized Bent Functions

    Sunghwan KIM  Gang-Mi GIL  Jong-Seon NO  

     
    PAPER-Coding Theory

      Vol:
    E87-A No:2
      Page(s):
    480-488

    In this paper, a new class of bent functions is constructed by combining class M and class C bent functions. Using the construction method of the class D bent functions defined on the binary vector space, new p-ary generalized bent functions are also introduced for odd prime p.

  • A Gm-C Filter Using Multiple-Output Linearized Transconductors

    Tadashi ARAI  Tetsuro ITAKURA  

     
    PAPER

      Vol:
    E87-A No:2
      Page(s):
    384-389

    A Gm-C filter using multiple-output transconductors suitable for reducing the chip area and power consumption is presented. The novel multiple-output transconductor is based on a translinear gain cell with a linearized input stage. Making good use of the linearized input stage, a simple common-mode feedback is also proposed for this multiple-output transconductor. Using the proposed technique, a 5th-order lowpass filter with two transmission zeros was designed and fabricated as a main part of a lowpass channel selection filter for UMTS receivers. A channel of the filter consumes 7 mA from a 2.7 V power supply and the integrated input-referred noise was 21 dBuV with 20 dB pass band gain. The proposed multiple-output technique saves roughly half the number of transconductors compared with the typical active ladder filter design. The proposed multiple-output transconductors achieve linearization and effective reduction while saving linearized input stages. They are suitable for a filter with small power consumption and small area.

  • An 8-GS/s 4-Bit 340 mW CMOS Time Interleaved Flash Analog-to-Digital Converter

    Young-Chan JANG  Sang-Hune PARK  Seung-Chan HEO  Hong-June PARK  

     
    PAPER

      Vol:
    E87-A No:2
      Page(s):
    350-356

    An 8-GS/s 4-bit CMOS analog-to-digital converter (ADC) chip was implemented by using a time interleaved flash architecture for very high frequency mixed signal applications with a 0.18-µm single-poly five-metal CMOS process. Eight 1-GS/s flash ADCs were time-interleaved to achieve the 8-GHz sampling rate. Eight uniformly-spaced 1 GHz clocks were generated by using a phase-locked-loop (PLL) with the peak-to-peak and rms jitters of 29.6 ps and 3.78 ps respectively. An input buffer including a preamplifier array (fifteen preamplifiers, four dummy amplifiers and averaging resistors) was shared among eight 1-GS/s flash ADCs to reduce the input capacitance and the mismatches among eight 1-GS/s flash ADCs. The adjacent output nodes of preamplifiers were connected by a resistor (resistor-averaging) to reduce the effects of the input offset voltage and the load mismatches of preamplifiers. A source follower circuit was added at the output node of a preamplifier to drive eight distributed track and hold (DTH) circuits. The Input bandwidth of ADC was measured to be 2.5 GHz. The measured SFDR values at the sampling rate of 8-GS/s were 25 dB and 22 dB for the 1.033 GHz and 2.5 GHz sinusoidal input signals respectively. The power consumption and the active input voltage range were 340 mW and 700 mV peak-to-peak, respectively, at the sampling rate of 8-GS/s and the supply voltage of 1.8 V. The active chip area was 1.32 mm2.

  • Macromodel Generation for Hybrid Systems Consisting of Electromagnetic Systems and Lumped RLC Circuits Based on Model Order Reduction

    Takayuki WATANABE  Hideki ASAI  

     
    PAPER

      Vol:
    E87-A No:2
      Page(s):
    398-405

    This paper describes an efficient method for the macromodel generation of hybrid systems which are composed of electromagnetic systems and lumped RLC circuits. In our method, electromagnetic systems are formulated as finite-difference frequency-domain (FDFD) equations, and RLC circuits are formulated as nodal equations. Therefore, unlike the partial-element equivalent-circuit (PEEC) method, the technique presented here does not need any 3-dimensional capacitance and inductance parameter extractions to model interconnects, LSI packages and printed circuit boards. Also the lumped RLC elements can be easily included in the hybrid system of equations, thus it is convenient to model some passive components, such as bypass capacitors. The model order reduction technique is utilized in order to construct macromodels from hybrid system of equations. The accuracy of the proposed method is substantiated with some numerical examples.

  • Improvement of Wavelet Based Parameter Estimations of Nearly 1/f Processes

    Shigeo WADA  Nao ITO  

     
    PAPER-Digital Signal Processing

      Vol:
    E87-A No:2
      Page(s):
    417-423

    Nearly 1/f processes are known as important stochastic models for scale invariant data analysis in a number of fields. In this paper, two parameter estimation methods of nearly 1/f processes based on wavelets are proposed. The conventional method based on wavelet transform with EM algorithm does not give the reliable parameter estimation value when the data length is short. Moreover, the precise parameter value is not estimated when the spectrum gap exists in 1/f processes. First, in order to improve the accuracy of the estimation when the data length is short, a parameter estimation method based on wavelet transform with complementary sampling is proposed. Next, in order to reduce the effect of spectrum gap, a parameter estimation method based on wavelet packet with EM algorithm is proposed. Simulation results are given to verify the effectiveness of the proposed methods.

  • Dual-Band Sigma-Delta Modulator for Wideband Receiver Applications

    Jen-Shiun CHIANG  Pao-Chu CHOU  Teng-Hung CHANG  

     
    PAPER

      Vol:
    E87-A No:2
      Page(s):
    311-323

    This work presents a new sigma-delta modulator (SDM) architecture for a wide bandwidth receiver. This architecture contains dual-bandwidth for W-CDMA and GSM system applications. Low-distortion swing-suppressing SDM and interpolative SDM cascaded units are used together. Using the low-distortion swing-suppressing technique, the resolution can be improved even under non-linearity effects. The interpolative SDM extends the signal bandwidth and represses the high-band noise. The SDM used in the W-CDMA and GSM applications was designed and simulated using 0.25-µm 1P5M CMOS technology. The simulated peak SNDR of W-CDMA and GSM are 72/70 dB and 82/84 dB in Low-IF/Zero-IF standards.

  • On the Properties of the Greatest Subsolution for Linear Equations in the Max-Plus Algebra

    Hiroyuki GOTO  Shiro MASUDA  

     
    PAPER-Systems and Control

      Vol:
    E87-A No:2
      Page(s):
    424-432

    This paper examines the properties of the greatest subsolution for linear equations in the max-plus algebra. The greatest subsolution is a relaxed solution of the linear equations, and gives a unified and reasonable solution whether there exists a strict solution or not. Accordingly, it forms part of a key algorithm for deriving a control law in the field of controller design, and some effective controllers based on the greatest subsolution have been proposed. However, there remain several issues to be discussed regarding the properties of the greatest subsolution. Hence, the main focus of this paper is on the following fundamental properties: 1) Formulation as an optimization problem, 2) Uniqueness of the greatest subsolution, 3) Necessary and sufficient condition for the correspondence of the greatest subsolution with the strict solution. These results could provide flexibility of the controller design based on the greatest subsolution, and facilitate the performance evaluation of the controller. Finally, the uniqueness of the strict solution of the linear equations is examined, and it is confirmed through illustrative examples.

  • A Time- and Communication-Optimal Distributed Sorting Algorithm in a Line Network and Its Extension to the Dynamic Sorting Problem

    Atsushi SASAKI  

     
    PAPER-Algorithms and Data Structures

      Vol:
    E87-A No:2
      Page(s):
    444-453

    This paper presents a strictly time- and communication-optimal distributed sorting algorithm in a line network. A strictly time-optimal distributed sorting algorithm in a line network has already been designed. However, its communication complexity is not strictly optimal and it seems to be difficult to extend it to other problems, such as that related to multiple elements in a process, and also the dynamic sorting problem where the number of elements each process should have as its solution is not the same as that in the initial state. Therefore, the algorithm in this paper was designed by an alternative approach to make it strictly time- and communication-optimal. Moreover, an extension to the dynamic sorting problem is described.

  • Two Step POS Selection for SVM Based Text Categorization

    Takeshi MASUYAMA  Hiroshi NAKAGAWA  

     
    PAPER

      Vol:
    E87-D No:2
      Page(s):
    373-379

    Although many researchers have verified the superiority of Support Vector Machine (SVM) on text categorization tasks, some recent papers have reported much lower performance of SVM based text categorization methods when focusing on all types of parts of speech (POS) as input words and treating large numbers of training documents. This was caused by the overfitting problem that SVM sometimes selected unsuitable support vectors for each category in the training set. To avoid the overfitting problem, we propose a two step text categorization method with a variable cascaded feature selection (VCFS) using SVM. VCFS method selects a pair of the best number of words and the best POS combination for each category at each step of the cascade. We made use of the difference of words with the highest mutual information for each category on each POS combination. Through the experiments, we confirmed the validation of VCFS method compared with other SVM based text categorization methods, since our results showed that the macro-averaged F1 measure (64.8%) of VCFS method was significantly better than any reported F1 measures, though the micro-averaged F1 measure (85.4%) of VCFS method was similar to them.

  • A Novel Contour Description with Expansion Ability Using Extended Fractal Interpolation Functions

    Satoshi UEMURA  Miki HASEYAMA  Hideo KITAJIMA  

     
    PAPER-Image Processing, Image Pattern Recognition

      Vol:
    E87-D No:2
      Page(s):
    453-462

    In this paper, a novel description method of the contour of a shape using extended fractal interpolation functions (EFIFs) is presented. Although the scope of application of traditional FIFs has been limited to cases in which a given signal is represented by a single-valued function, the EFIFs derived by the introduction of a new parameter can describe a multiple-valued signal such as the contour of a shape with a high level of accuracy. Furthermore, the proposed description method possesses the useful property that once a given contour has been modeled by the proposed description method, the shape can be easily expanded at an arbitrary expansion rate. Experimental results show the effectiveness and usefulness of the proposed description method for representing contours.

  • UPRISE: Unified Presentation Slide Retrieval by Impression Search Engine

    Haruo YOKOTA  Takashi KOBAYASHI  Taichi MURAKI  Satoshi NAOI  

     
    PAPER

      Vol:
    E87-D No:2
      Page(s):
    397-406

    A combination of slides used in a presentation and a video recording of the circumstances of the presentation are quite useful for many applications, such as e-learning. However, to create new content from these with current authoring tools requires considerable effort for the author and the products have reduced flexibility. In this paper, we propose the preparation of a unifying function without creating new content manually. We also propose a new approach to search unified presentation manuscripts for slides matched with given keywords by considering the features peculiar to the presentation slides. We propose impression indicators to express how well a slide matches the given keywords. We also propose a system for retrieving a sequence of desired presentation slides from archives of the combined slides and video. We named the system Unified Presentation Slide Retrieval by Impression Search Engine or UPRISE. We describe the system configuration of UPRISE and the experimentation undertaken to evaluate the effect of the proposed indicators and to compare the results with those of the traditional tf.idf retrieval method.

  • Relationships between Horn Formulas and XOR-MDNF Formulas

    Kenshi MATSUO  Tetsuya KOYAMA  Eiji TAKIMOTO  Akira MARUOKA  

     
    PAPER

      Vol:
    E87-D No:2
      Page(s):
    343-351

    We study relationships between the class of Boolean formulas called exclusive-or expansions based on monotone DNF formulas (MDNF formulas, for short) and the class of Horn DNF formulas. An MDNF formula f is a Boolean formula represented by f = f1fd , where f1 > > fd are monotone DNF formulas and no terms appear more than once. A Horn DNF formula is a DNF formula where each term contains at most one negative literal. We show that the class of double Horn functions, where both f and its negation can be represented by Horn DNF formulas, coincides with a subclass of MDNF formulas such that each DNF formula fi consists of a single term. Furthermore, we give an incrementally polynomial time algorithm that transforms a given Horn DNF formula into the MDNF representation.

  • Time-Efficient Multicast to Local Vertices in Star Interconnection Networks under the Single-Port Model

    Satoshi FUJITA  

     
    PAPER

      Vol:
    E87-D No:2
      Page(s):
    315-321

    In this paper, we consider the problem of constructing a multicast tree in the star graph under the single-port communication model. Unlike previous studies for constructing space-efficient multicast trees, we adopt the completion time of each multicast as the objective function to be minimized. In particular, we study a special case of the problem in which all destination vertices are immediate neighbors of the source vertex, and propose a multicast scheme for the star graph of dimension n in 1.3125log2 n + O(log log n) time units. This running time is at most 1.3125 times of that of an optimal scheme.

  • A Self-Stabilizing Distributed Algorithm for the Steiner Tree Problem

    Sayaka KAMEI  Hirotsugu KAKUGAWA  

     
    PAPER

      Vol:
    E87-D No:2
      Page(s):
    299-307

    Self-stabilization is a theoretical framework of non-masking fault-tolerant distributed algorithms. In this paper, we investigate the Steiner tree problem in distributed systems, and propose a self-stabilizing heuristic solution to the problem. Our algorithm is constructed by four layered modules (sub-algorithms): construction of a shortest path forest, transformation of the network, construction of a minimum spanning tree, and pruning unnecessary links and processes. Competitiveness is 2(1-1/l), where l is the number of leaves of optimal solution.

  • On the Open Problems Concerning Church-Rosser of Left-Linear Term Rewriting Systems

    Michio OYAMAGUCHI  Yoshikatsu OHTA  

     
    PAPER

      Vol:
    E87-D No:2
      Page(s):
    290-298

    G.Huet (1980) showed that a left-linear term-rewriting system (TRS) is Church-Rosser (CR) if P Q for every critical pair where P Q is a parallel reduction from P to Q. But, it remains open whether it is CR when Q P for every critical pair . In this paper, we give a partial solution to this problem, that is, a left-linear TRS is CR if Q P for every critical pair where Q P is a parallel reduction with the set W of redex occurrences satisfying that if the critical pair is generated from two rules overlapping at an occurrence u, then the length |w| |u| for every w W. We also show that a left-linear TRS is CR if Q P for every critical pair generated from two rules overlapping at an occurrence u. Here, Q P is either Q = P or a reduction whose redex occurrence is not greater than u. This condition is incomparable with the previous one and a partial solution to the open problem of ascertaining whether it is CR when Q P for every critical pair .

  • Serial Concatenation of Space-Time Trellis Code with Convolutional Code over Fast Rayleigh Fading Channel

    Moo Sam KIM  Je Gil KOO  

     
    LETTER-Wireless Communication Technology

      Vol:
    E87-B No:2
      Page(s):
    373-376

    This letter presents a new concatenated code and a new criterion for the new concatenated code in fast Rayleigh fading channel. The new concatenated code consists of the cascade of a new space-time trellis code (STTC) as an inner code and a new convolutional code as an outer code. The new criterion maximizes the minimum free distance for the new convolutional code and both the minimum trace and the average trace of distance matrix for the new STTC. The new concatenated code improves the frame error rate (FER) performance significantly with low complexity. The new STTC and convolutional code are designed so as to satisfy the new criterion for 4-state 4 phase shift keying (PSK). The results of the suggested concatenated code are obtained using two transmit antennas, and shown to be significantly superior to the new and existing STTCs. As the number of receive antennas increases, the performance of the new concatenated code significantly improves, for instance, reaches FER = 10-3 at signal-to-noise ratio (SNR) = 5.2 dB for four receive antennas. Note that the proposed concatenated code also improves significant FER performance by using only one receive antenna for high SNR.

20521-20540hit(30728hit)