• Title/Summary/Keyword: Link Quality

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Multi-Criteria Decision-Making Model Using Quality Function Deployment (QFD) Method for the Most Suitable Temporary Earth Retaining System

  • Jung, Bae Yu;Byung, Cho Han;Jin, Han Sang;Won, Kwon;Ho, Jo Jae;Youl, Chun Jae
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.620-621
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    • 2015
  • In this study, the multi-criteria decision-making model based on Quality Function Deployment Method is proposed. Multicriteria decision-making is an attempt to link QFD method with the TOPSIS. By this effort, a model that makes client's decision-making more rational and objective in design phase is suggested. The multi-criteria decisionmaking model confirming to the Owner's requirements will improve the productivity of the construction industry and the satisfaction of the customer. Further study extending the range of the requirements, not only the Owner's requirement will be necessary to cover the various factors as much as possible. And then, finally as a flexible platform to achieve a sustainable quality management, web-based multi-criteria decision-making model can be utilized by the relevant stakeholders simultaneously with the feed-back and sharing the necessary informations.

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Deming prize and malcolm baldrige national quality award

  • Ryu, Seewon;Jo, Hongkyu;Heo, Jaeho
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1995.04a
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    • pp.827-844
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    • 1995
  • Total Quality Management (TQM) is the aggregated management philosophy for quality including production, operation, human resource, leadership, marketing, and etc. TQM is the advanced concept and philosophy rather than traditional "Quality Control" or "Quality Assurance". Nowadays, downstream costs has been increased, that made cost accountants' attention to costs of quality. Many countries have developed their own quality awards system in order to improve overall national quality level. The Deming Prize of Japan and Malcolm Baldrige National Quality Award (MBNQA) of United States are two representatives of quality prizes. We compared the two awards by means of their history, objective, coverage, and judging criteria. Deming Prize has a longer history than MBNQA. Deming Prize selects five winners a year, while MBNQA has two or three areas. The biggest difference is judgement criteria. The Deming Prizes focuses on statistical control which is a traditional quality control method, while MBNQA concentrates on modem business concept such as customer satisfaction. The suggestions to these awards are: evaluate more on information of quality; evaluate more on inter-functional relationship between quality control function and other link more financial success.e financial success.

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Performance Evaluation of Service-Aware Optical Transport System

  • Youn, Ji-Wook;Yu, Jea-Hoon;Yoo, Tae-Whan
    • ETRI Journal
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    • v.32 no.2
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    • pp.241-247
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    • 2010
  • We propose and experimentally demonstrate a service-aware optical transport system. The proposed service-aware optical transport system makes a flow based on service type and priority of traffic. The generated flow is mapped to a corresponding sub-${\lambda}$ for transport over an optical network. Using sub-${\lambda}$ provided by the centralized control plane, we could effectively provide quality-of-service guaranteed Ethernet service and best-effort service simultaneously in a single link. The committed information rate (CIR) traffic and best-effort traffic are assigned to different sub-${\lambda}s$. The bandwidth of the CIR traffic is guaranteed without being affected by violation traffic because the bandwidth is managed per each sub-${\lambda}$. The failure detection time and restoration time from a link failure is measured to be about 60 ${\mu}s$ and 22 ms, respectively, in the ring network. The measured restoration time is much smaller than the 50 ms industry requirement for real-time services. The fast restoration time allows the proposed service-aware optical transport system to offer high availability and reliability which is a requirement for transport networks.

Radio Resource Metric Estimation (RRME) Mechanism for Multimedia Service Applications based on a CDMA Communication System

  • Lee Yeon-Woo;Cho Kwang-Moon;Hur Kyeong
    • International Journal of Contents
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    • v.2 no.2
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    • pp.10-16
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    • 2006
  • In this paper, we propose a predictive resource metric region (RMR) based radio resource metric estimation (RRME) mechanism, which utilizes a resource metric mapping function (RMMF), both of which permit efficient inter-working between the physical layer and higher layers for envisaging multimedia service applications over a CDMA communication system platform. The RMR can provide the acceptable resource region where QoS and acceptable link quality can be guaranteed with an achievable resource margin to be utilized in terms of capacity margin, the degree of confidence (DCL) of user, second-order statistics of Eb/Io. With predicted capacity margin and variance, DCL can deliver decision parameters with which an adaptive QoS based admission control can perform well taking capacity and resource availability into account in a dynamic and predictive manner. Combined with advanced techniques such as adaptive modulation or rate control and power control, the proposed mechanism can adjust the conventional stringent link quality information efficiently, and deliver accurate information of the resource availability. Thus, these can guarantee the maximization of resource utilization of multimedia service applications.

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Load Balancing and Mobility Management in Multi-homed Wireless Mesh Networks

  • Tran, Minh Tri;Kim, Young-Han;Lee, Jae-Hwoon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.5
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    • pp.959-975
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    • 2011
  • Wireless mesh networks enlarge the wireless coverage area by interconnecting relatively stationary wireless routers (mesh routers). As wireless mesh networks are envisioned to provide high-bandwidth broadband Internet service to a large community of users, the Internet gateway, which acts as a central point of Internet attachment for the mesh networks, is likely to suffer heavily from the scramble for shared wireless resources because of aggregated traffic toward the Internet. It causes performance decrement on end-to-end transmissions. We propose a scheme to balance the load in a mesh network based on link quality variation to different Internet gateways. Moreover, under the mesh coverage, mobile nodes can move around and connect to nearby mesh routers while still keeping the connections to the Internet through the best gateway in terms of link quality. In this structure, gateways perform the balancing procedure through wired links. Information about gateways and mobile node's location is distributed appropriately so that every mesh router can quickly recognize the best gateway as well as the positions of mobile nodes. This distributed information assists mobile nodes to perform fast handoff. Significant benefits are shown by the performance analysis.

Performance Analysis of STTC-based Dual Virtual Cell System under The Overlay Convergent Networks of Cognitive Networking (중첩 융합 네트워크 환경에서 STTC기반 이중 셀 시스템의 성능분석)

  • Kwon, Eun-Mi;Kim, Jeong-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.7A
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    • pp.528-534
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    • 2012
  • In order to achieve high capacity and reliable link quality of the overlay convergent networks with the cognitive networking based on the advanced capability of the mobile terminal, a Distributed Wireless Communication System (DWCS) can provide the capability of enhancing the link quality. This paper has considered virtual cell: the Dual Virtual Cell (DVC), and also proposes DVC employment strategy based on radio resource monitering. The considered system constructs DVC for multi-user high-rate data transmission, and the DWCS system exploits space-time trellis codes i.e., STTC to improve a spectral efficiency. The effects of imperfect CSI(channel state information) on the system performance has also been investigated.

Application of Fuzzy PI Control Algorithm as Stator Power Controller of a Double-Fed Induction Machine in Wind Power Generation Systems

  • Chung, Gyo-Bum;Choi, Jae-Ho
    • Journal of Power Electronics
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    • v.9 no.1
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    • pp.109-116
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    • 2009
  • This paper addresses the output control of a utility-connected double-fed induction machine (DFIM) for wind power generation systems (WPGS). DFIM has a back-to-back converter to control outputs of DFIM driven by the wind turbine for WPGS. To supply commercially the power of WPGS to the grid without any problems related to power quality, the real and reactive powers (PQ) at the stator side of DFIM are strictly controlled at the required level, which in this paper is realized with the Fuzzy PI controller based on the field orientation control. For the Sinusoidal Pulse Width Modulation (SPWM) converter connected to the rotor side of DFIG to maintain the controllability of PQ at the state side of DFIM, the DC voltage of the DC link capacitor is also controlled at a certain level with the conventional Proportion-Integral (PI) controller of the real power. In addition, the power quality at the grid connected to the rotor side of DFIM through the back-to-back converter is maintained in a certain level with a PI controller of the reactive power. The controllers for the PQ at the stator side of DFIM, the DC link voltage of the back-to-back inverter and the reactive power at the grid connected to the rotor side of DFIM are designed and simulated in the PSIM program, of which the result verifies the performance of the proposed controllers.

Orthogonal Frequency Division Multiple Access with Statistical Channel Quality Measurements Part-I: System and Channel Modeling (통계적 채널 Quality 정보를 이용한 직교 주파수분할 다중접속(OFDMA) Part-I: 시스템 및 채널 모델링)

  • Yoon, Seo-Khyun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.2A
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    • pp.119-127
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    • 2006
  • In this two-part paper, we consider dynamic resource allocation in orthogonal frequency division multiple access(OFDMA). To reduce the reverse link overhead for channel quality information(CQI) feedback, a set of sub-carriers are tied up to a sub-channel to be used as the unit of CQI feedback, user-multiplexing and the corresponding power/rate allocation. Specifically, we focus on two sub-channel structures, either aggregated or distributed, where the SNR distribution over a sub-channel is modeled as Ricean in general, and the channel quality of a sub-channel is summarized as the mean and variance of channel gain envelop divided by noise standard deviation. Then, we develop a generalized two step channel/resource allocation algorithm, which uses the two statistical measurements, and analyze the spectral efficiency of the OFDMA system in terms of average frequency utilization. An extension to proportional fair algorithm will also be addressed. As confirmed by numerical results, the aggregated structure is preferred especially when intending aggressive link adaptation.

A Study on the Estimation of the Call Drop Rate for Call Admission Control in DS-CDMA Reverse Link (DS-CDMA 역방향 링크에서 호수락 제어를 위한 호 절단률 추정에 관한 연구)

  • 백진현;박용완
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.12B
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    • pp.1677-1685
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    • 2001
  • In this paper, we propose a call admission control scheme that can be performed within guaranteeing of required QoS(Quality of Services) in DS-CDMA(Direct Sequence-Code Division Multiple Access) reverse link. It has been performed rely on a physical channel numberonly and based on quality of received signal from MODEM(modulator/demodulator) part in established study. In other methods, the standard for services would have been set from statistical analysis of users\` location and using received power level in BTS(Base Transceiver Station). These ways bring about not only system loads but time delay or great differences from real environment. To solve these problems, we propose a call drop rate estimation algorithm for the purpose of call admission control based on measured value at LNA(Low Noise Amplifier) ports of BTS(Base Transceiver Station) in real time. This method proposed in this paper estimates a quality of offered service in real time, reduce system loads and shorten time delay which is needed to determine the standard for call admission control. But it requires a additional 17W complexity which can measure received signal power in BTS and estimate call drop rate.

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A Traffic and Link Quality Based Congestion Control Scheme for Reliable Sensing Data Delivery in Wireless Sensor Networks (무선 센서 네트워크에서 신뢰성 있는 센싱 정보 전달을 위한 트래픽 및 링크 품질 기반 혼잡 제어 기법)

  • Kim, Sungae;Chung, Sanghwa
    • Journal of KIISE:Information Networking
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    • v.41 no.4
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    • pp.177-185
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    • 2014
  • It has been occurred many times that wireless sensor networks (WSNs) had congested areas because all the sensing data collected by multiple sensor nodes are delivered to one sink node. Typically, in order to control congested areas, it used to reduce the traffic by increasing the sensing period or discarding packets. However, those schemes have a disadvantage that it loses the reliability when delivering sensing data. Moreover, there are no schemes considering case of having poor quality of links between nodes in practical terms. In this paper, we suggest a scheme not to reduce the traffic but to distribute the traffic by changing routing paths depends on the traffic and the quality of links. Also, it can be seen that the reliability of delivering of the sensing data is improved with the experiments improving collection rates and shortening end-to-end delay.