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[Author] Chang CHEN(14hit)

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  • Traffic Engineering for Provisioning Restorable Hose-Model VPNs

    Yu-Liang LIU  Yeali Sunny SUN  Meng Chang CHEN  

     
    PAPER

      Vol:
    E89-B No:9
      Page(s):
    2394-2403

    Virtual Private Networks (VPNs) are overlay networks established on top of a public network backbone with the goal of providing a service comparable to Private Networks (PNs). The recently proposed VPN hose-model provides customers with flexible and convenient ways to specify their bandwidth requirements. To meet the specified bandwidth requirements, the Network Service Provider (NSP) must reserve sufficient bandwidth on the data transmission paths between each pair of endpoints in a VPN. In addition, the reliability of a VPN depends on the reliability of the data transmission paths. Italiano et al. proposed an algorithm that finds a set of backup paths for a given VPN (VPN tree) under the single-link failure model [1]. When a link failure is detected on a VPN tree, a backup path corresponding to the failed link can be activated to restore the disconnected VPN tree into a new one, thereby ensuring the reliability of the VPN. However, Italiano's algorithm cannot guarantee that the specified bandwidth requirement of the given VPN under the single-link failure model will be met. To address this issue, we propose a new backup path set selection algorithm called BANGUAD in this paper. In addition, the problem of establishing multiple bandwidth-guaranteed hose-model VPNs under the single-link failure model has not been investigated previously. However in this problem, bandwidth-sharing algorithms have the potential to improve the performance of a provisioning algorithm significantly. Therefore, we also propose a bandwidth sharing algorithm and three provisioning algorithms for establishing multiple bandwidth-guaranteed hose-model VPNs under the single-link failure model. Simulations that compare the performance of the proposed algorithms are reported.

  • A Design of GS1 EPCglobal Application Level Events Extension for IoT Applications

    Chao-Wen TSENG  Yu-Chang CHEN  Chua-Huang HUANG  

     
    PAPER

      Pubricized:
    2015/10/21
      Vol:
    E99-D No:1
      Page(s):
    30-39

    EPCglobal architecture framework is divided into identify, capture, and share layers and defines a collection of standards. It is not fully adequate to build IoT applications because the transducer capability is lacking. IEEE 1451 is a set of standards that defines data exchange format, communication protocols, and various connection interfaces between sensors/actuators and transducer interface modules. By appending IEEE 1451 transducer capability to EPCglobal architecture framework, a consistent EPC scheme expression for heterogeneous things can be achieved at identify layer. It is benefit to extend the upper layers of EPCglobal architecture framework seamlessly. In this paper, we put our emphasis on how to leverage the transducer capability at the capture layer. A device cycle, transducer cycle specification, and transducer cycle report are introduced to collect and process sensor/actuator data. The design and implementation of GS1 EPCglobal Application Level Events (ALE) modules extension are proposed for explaining the design philosophy and verifying the feasibility. It will interact with the capture and query services of EPC Information Services (EPCIS) for IoT applications at the share layer. By cooperating and interacting with these layers of EPCglobal architecture framework, the IoT architecture EPCglobal+ based on international standards is built.

  • Histogram Matching by Moment Normalization

    Wen-Hao WANG  Yung-Chang CHEN  

     
    LETTER-Image Processing,Computer Graphics and Pattern Recognition

      Vol:
    E80-D No:7
      Page(s):
    746-750

    A moment-based method is proposed to estimate the illumination change between two images containing affinetransformed objects. The change is linearly modeled with parameters to be estimated by histograms due to its invariance of translation, rotation, and scaling. The parameters can be correctly estimated for an appropriate illumination change by normalizing the moments of the histograms.

  • Improving RF CMOS Active Inductor by Simple Loss Compensation Network

    Chen-Yi LEE  Jyh-Neng YANG  Yi-Chang CHENG  

     
    LETTER-Communication Devices/Circuits

      Vol:
    E87-B No:6
      Page(s):
    1681-1683

    An RF CMOS active inductor with a novel loss compensation circuit network is proposed. Performance of this active inductor can be improved by adding a novel network, which simultaneously reduces parallel and series losses. Consequently, this technique not only increases Q value, inductance, and operating frequency, but also reduces power consumption and circuit complexity. Simulation results show that better performance indices can be achieved, such as minimum total equivalent loss of 1 mΩ, maximum Q value about 3E5, and inductance value from 20 nH to 45 nH in the RF range of 0.6 GHz to 1.6 GHz. Power dissipation is around 1.76 mW under 2.5 V dc supply voltage.

  • Partial Label Metric Learning Based on Statistical Inference

    Tian XIE  Hongchang CHEN  Tuosiyu MING  Jianpeng ZHANG  Chao GAO  Shaomei LI  Yuehang DING  

     
    PAPER-Artificial Intelligence, Data Mining

      Pubricized:
    2020/03/05
      Vol:
    E103-D No:6
      Page(s):
    1355-1361

    In partial label data, the ground-truth label of a training example is concealed in a set of candidate labels associated with the instance. As the ground-truth label is inaccessible, it is difficult to train the classifier via the label information. Consequently, manifold structure information is adopted, which is under the assumption that neighbor/similar instances in the feature space have similar labels in the label space. However, the real-world data may not fully satisfy this assumption. In this paper, a partial label metric learning method based on likelihood-ratio test is proposed to make partial label data satisfy the manifold assumption. Moreover, the proposed method needs no objective function and treats the data pairs asymmetrically. The experimental results on several real-world PLL datasets indicate that the proposed method outperforms the existing partial label metric learning methods in terms of classification accuracy and disambiguation accuracy while costs less time.

  • MinDoS: A Priority-Based SDN Safe-Guard Architecture for DoS Attacks

    Tao WANG  Hongchang CHEN  Chao QI  

     
    PAPER-Information Network

      Pubricized:
    2018/05/02
      Vol:
    E101-D No:10
      Page(s):
    2458-2464

    Software-defined networking (SDN) has rapidly emerged as a promising new technology for future networks and gained considerable attention from both academia and industry. However, due to the separation between the control plane and the data plane, the SDN controller can easily become the target of denial-of service (DoS) attacks. To mitigate DoS attacks in OpenFlow networks, our solution, MinDoS, contains two key techniques/modules: the simplified DoS detection module and the priority manager. The proposed architecture sends requests into multiple buffer queues with different priorities and then schedules the processing of these flow requests to ensure better controller protection. The results show that MinDoS is effective and adds only minor overhead to the entire SDN/OpenFlow infrastructure.

  • A Novel RF CMOS Active Inductor

    Jyh-Neng YANG  Yi-Chang CHENG  Chen-Yi LEE  

     
    LETTER-Communication Devices/Circuits

      Vol:
    E86-B No:7
      Page(s):
    2190-2192

    A novel RF CMOS high Q-value active inductor is proposed in this work by using simple cascode RC feedback compensation technique. The performance of this active inductor has maximum Q-value about 1.2E6, inductance value from 3.5 nH to 4.5 nH and 3E-5Ω of minimum total equivalent loss, in the range of 1.2 GHz to 2 GHz.

  • On Relation between Reliability and Topology of Starred Polygon with Redundant Nodes

    Chang CHEN  Yoshihiro TAKADA  Tohru KIKUNO  Koji TORII  

     
    LETTER-Graphs and Networks

      Vol:
    E73-E No:11
      Page(s):
    1782-1784

    This letter discusses a relation between reliability and network topology of starred polygon with redundant nodes. Each node of starred polygon is augmented by a spare node, and the degree of survivability is newly defined to evaluate reliability. The main result presents three special topologies of starred polygon with redundant nodes that realize an optimal degree of survivability.

  • A Low-Complexity Face-Assisted Coding Scheme for Low Bit-Rate Video Telephony

    Chia-Wen LIN  Yao-Jen CHANG  Yung-Chang CHEN  

     
    PAPER-Image Processing, Image Pattern Recognition

      Vol:
    E86-D No:1
      Page(s):
    101-108

    This paper presents a novel and practical face-assisted video coding scheme to enhance the visual quality of the face region in videophone applications. A low-complexity skin-color-based face detection and tracking scheme is proposed to locate the human face regions in realtime. After classifying the macroblocks (MBs) into the face and non-face regions, we present a dynamic distortion-weighting adjustment (DDWA) scheme to skip encoding the static non-face MBs, and the saved bits are used to compensate the face region by increasing the distortion weighting of the face MBs. The quality of the face regions will thus be largely enhanced. Moreover, the computation originally required for encoding the skipped MBs can also be saved. The experimental results show that the proposed method can significantly improve the PSNR and the subjective quality of face regions, while the degradation introduced on the non-face areas is relatively invisible to human perception. The proposed algorithm is fully compatible with the H. 263 standard, and the low complexity feature makes it well suited to be implemented for real-time applications.

  • A Buffer Occupancy-Based Adaptive Flow Control and Recovery Scheme for Real-Time Stored MPEG Video Transport over Internet

    Yeali S. SUN  Fu-Ming TSOU  Meng Chang CHEN  

     
    PAPER-Media Management

      Vol:
    E81-B No:11
      Page(s):
    1974-1987

    As the current Internet becomes popular in information access, demands for real-time display and playback of continuous media are ever increasing. The applications include real-time audio/video clips embedded in WWW, electronic commerce, and video-on-demand. In this paper, we present a new control protocol R3CP for real-time applications that transmit stored MPEG video stream over a lossy and best-effort based network environment like the Internet. Several control mechanisms are used: a) packet framing based on the meta data; b) adaptive queue-length based rate control scheme; c) data preloading; and d) look-ahead pre-retransmission for lost packet recovery. Different from many adaptive rate control schemes proposed in the past, the proposed flow control is to ensure continuous, periodic playback of video frames by keeping the receiver buffer queue length at a target value to minimize the probability that player finds an empty buffer. Contrary to the widespread belief that "Retransmission of lost packets is unnecessary for real-time applications," we show the effective use of combining look-ahead pre-retransmission control with proper data preloading and adaptive rate control scheme to improve the real-time playback performance. The performance of the proposed protocol is studied via simulation using actual video traces and actual delay traces collected from the Internet. The simulation results show that R3CP can significantly improve frame playback performance especially for transmission paths with poor packet delivery condition.

  • Spare Processor Assignment for Reconfiguration of Fault-Tolerant Arrays

    Chang CHEN  An FENG  Yoshihiro TAKADA  Tohru KIKUNO  Koji TORII  

     
    PAPER

      Vol:
    E73-E No:8
      Page(s):
    1247-1256

    To provide the processor arrays with adequate fault-tolerant capabilities, a number of spare or redundant processors are prepared within the arrays. For such processor arrays, reconfiguration should be executed to bypass faulty processors. Concerning reconfiguration of processor arrays, Melhem presented a minimization problem (called the SPA problem). The SPA problem is to find an assignment of spare processors to faulty processors that minimizes the number of dangerous processors. Here, the dangerous processors are processors, for which there remains no longer any spare processor to be assigned when one more faults occur. In this paper, we present a more rigorous definition of the SPA problem, in which input parameters are n2 ordinary processors, 2n spare processors and m (mn2) faulty processors, and the output is an optimal assignment of spare processors to faulty processors, in the sense that the number of dangerous processors is minimum. Then, we develop an efficient algorithm based on the necessary and sufficient conditions, which allows highly efficient computation of spare processor assignment. The worstcase time complexity of the proposed algorithm is O(n2).

  • Placement of VBR Video on Zoned Disks for Real-Time Playback

    Shiao-Li TSAO  Meng Chang CHEN  Yeali Sunny SUN  

     
    PAPER-Databases

      Vol:
    E84-D No:12
      Page(s):
    1767-1781

    Disk-zoning technique has been widely adopted to increase disks capacities. As a result of disparity of capacities of inner and outer zones, the data transfer rates of the outer zones of a zoned-disk are higher than the inner zones that post a great challenge for zoned-disk based multimedia playback. In this paper, we study the data placement problem of VBR (variable bit rate) videos on zoned-disks. Our objective is to minimize video server buffer size and simultaneously to maximize disk utilization subject to the zone constraints of disk. We introduce the CRT (constant read time) method that allocates each user a constant time period in every service round to retrieve a variable-sized disk block. The CRT method can be formulated as constrained combinatorial problems that its optimum solution can be obtained by employing dynamic programming. Two heuristics are also explored to reduce time and space complexities. According to experiment results, the heuristic algorithms obtain near optimum solutions with shorter computation time.

  • Reconfiguration Algorithm for Modular Redundant Linear Array

    Chang CHEN  An FENG  Yoshiaki KAKUDA  Tohru KIKUNO  

     
    PAPER-Fault Tolerant Computing

      Vol:
    E76-D No:2
      Page(s):
    210-218

    A typical fault-tolerance technique of systolic arrays is to include redundant processors and links so that the array is reconfigurable when some processors fail. Another typical technique is to implement each processor by a majority voter and N (N3) copies of processors so that the faults of up to N-2 copies of processors can be masked without reconfiguration. This paper proposes a systolic linear array called reconfigurable modular redundant linear array (RMA) that combines these techniques with N4. When up to 2 copies of each processor fail in RMA, the faults can be masked without reconfiguration. When some voters or more than 2 copies of a processor fail, RMA can be reconfigured by specifying a new switch pattern. In order to perform reconfiguration efficiently, we present a reconfiguration algorithm with time complexity O (n), where n is the number of processors in RMA.

  • Design Issues in Multi-Zone Disks Video-on-Demand Systems

    Chin-Hwa KUO  Li-Chun SUNG  Meng-Chang CHEN  

     
    PAPER-Computer Systems

      Vol:
    E83-D No:5
      Page(s):
    1058-1072

    A systematic continuous data placement scheme on distributed multi-zone disks is developed for video on demand. The proposed scheme makes use of constant read time concept, i. e. , each video stream has the same access time in each service round when serving the request. The developed scheme maximizes not only the averaged data transmitted rate, but also the number of simultaneous accesses. The scheme consists of the following components. First we developed an algorithm that reorganizes the multi-zone disk into several logical zones in the sense that the averaged disk throughput is maximum. Second, a sequential data access method was developed that takes disk loading balance into account. Thus, at each service round, the total amount of data transmitted is a constant. Third, we introduce the idle round technique to reduce the buffer size required at the client site for VBR video stream. As a result, admission control is enforced in an efficient manner. Finally we perform experimental tests to evaluate the performance of the proposed scheme. The results indicate the value of the proposed scheme.