• The Journal of Korea Robotics Society
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• v.11 no.4
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• pp.270-276
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• 2016

This paper proposes a design methodology of self-reconfigurable kinematics and control engine for modular and reconfigurable robots. A modular manipulator has been proposed to meet the requirement of task adaptation in versatile needs for service and industrial robot area and the function of self-reconfiguration is required to extend the application of modular robots. Kinematic and dynamic contexts are extracted from the module and assembly information and related codes are automatically generated including controller. Thus a user can easily build and use a modular robot without professional knowledge. Simulation results are presented to verify the validity of the proposed method.

• Journal of Power Electronics
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• v.16 no.3
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• pp.1012-1024
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• 2016

This study deals with an on-line software fault detection, localization, and system reconfiguration method for electrical system drives composed of three-phase AC/DC/AC converters and three-phase permanent magnet synchronous machine (PMSM) drives. Current sensor failure (outage), speed/position sensor loss (disconnection), and damaged DC-link voltage sensor are considered faults. The occurrence of these faults in PMSM drive systems degrades system performance and affects the safety, maintenance, and service continuity of the electrical system drives. The proposed method is based on the monitoring signals of "abc" currents, DC-link voltage, and rotor speed/position using a measurement chain. The listed signals are analyzed and evaluated with the generated residuals and threshold values obtained from a Sliding Mode Current-Speed-DC-link Voltage Observer (SMCSVO) to acquire an on-line fault decision. The novelty of the method is the faults diagnosis algorithm that combines the use of SMCSVO and adaptive thresholds; thus, the number of false alarms is reduced, and the reliability and robustness of the fault detection system are guaranteed. Furthermore, the proposed algorithm's performance is experimentally analyzed and tested in real time using a dSPACE DS 1104 digital signal processor board.

• Journal of Communications and Networks
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• v.18 no.4
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• pp.567-579
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• 2016

Several energy saving techniques in cellular wireless networks such as active base station (BS) selection, transmit power budget adaptation and user association have been studied independently or only part of these aspects have been considered together in literature. In this paper, we jointly tackle these three problems and propose an integrated framework, called dynamic cell reconfiguration (DCR). It manages three techniques operating on different time scales for ultimate energy conservation while guaranteeing the quality of service (QoS) level of users. Extensive simulations under various configurations, including the real dataset of BS topology and utilization, demonstrate that the proposed DCR can achieve the performance close to an optimal exhaustive search. Compared to the conventional static scheme where all BSs are always turned on with their maximum transmit powers, DCR can significantly reduce energy consumption, e.g., more than 30% and 50% savings in uniform and non-uniform traffic distribution, respectively.

• Journal of Internet Computing and Services
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• v.7 no.2
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• pp.121-136
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• 2006

Software architecture and protocols to be maintained between components for the reconfigurable SDR system is analyzed and suggest system design idea for the implementation of software. To do this, related surveys are reviews and set up the system model with the structure of embedded system. SDR system architecture is suggested with five layered structure, consisted with hardware, operating system, middle-ware, service objects and application layer. SDR system is designed to be work on the basis of Linux operating system, and aimed to be scalable and reconfigurable. It is introduced the design result of software protocol and state transition diagram for the implementations of software download function which is the most important feature in SDR.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.933-934
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• 2013

국내 B2C 서비스 산업의 경쟁력을 높이기 위해서는 고객 중심의 피드백 분석 및 프로세스 개선이 필요하다. 그러나 현재 우리나라는 B2C서비스와 관련하여 고객의견 수집 및 분석기술이 미흡하다. 본 연구에서는 다양한 방법으로 고객 피드백 정보를 수집 및 분석하고, 이를 기반으로 서비스를 재구성할 수 있는 프로세스 추론 방법을 제안한다. 이것을 위해 고객 피드백 정보와 프로세스 분석 정보를 바탕으로 서비스 온톨로지 모델링을 한다. 향후, 그것을 기반으로 한 추론을 통해 서비스 추천, 서비스 재구성, 프로세스 최적화를 위한 정보를 제공할 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1050-1061
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• 2000

This paper presents a new object model, LOM(Lightweight Object Model) and an implementation method for the distributed trader in heterogeneous distributed computing environment including mobile network. Trader is third party object that enables clients to find suitable servers, which provide the most appropriate services to client in distributed environment including dynamic reconfiguration of services and servers. Trading service requires simpler and more specific object model than genetic object models which provide richer multimedia data types and semantic characteristics with complex data structures. LOM supports a new reference attribute type instead of the relationship, inheritance and composite attribute types of the general object oriented models and so LOM has simple data structures. Also in LOM, the modelling step includes specifying of the information about users and the access right to objects for security in the mobile environment and development of the distributed storage for trading service. Also, we propose and implementation method of the distributed trader, which integrates the LOM-information object model and the OMG (object Management Group) computational object model.

• Proceedings of the Korean Society of Computer Information Conference
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• 2008.06a
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• pp.105-110
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• 2008

웹서비스는 XML기반의 표준인 SOAP, WSDL, UDDI를 이용하여 인터넷을 통해 기능을 제공해 주는 서비스 기반 아키텍처의 대표적 기술이다. 웹서비스의 개수가 많아지고 종류가 다양해짐에 따라, 요청자의 요구사항에 맞는 웹서비스를 선택하는 것이 중요하게 되었으며, 여기서 웹서비스의 선택 시 QoS(Quality of Service)는 중요한 기준이 된다. 하지만 웹서비스의 QoS는 동적으로 변하고, 이로 인해 요청자의 QoS요구사항에 만족하지 않는 웹서비스가 되기도 한다. 본 논문에서는 요청자의 QoS요구사항에 적합한 웹서비스를 찾고, 웹서비스의 QoS변화로 인하여 웹서비스를 동적으로 변경하는 프레임워크를 제안한다. 그리고 웹서비스를 동적으로 변경하는 경우에 필요한, 각 웹서비스의 인터페이스 적응 및 기존 작업의 보장에 대한 해결방법도 함께 제시한다.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.500-502
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• 1995

Whenever faults(a fault) occur(s) in a particular section of a distribution system, some of loads get disconnected and are left unsupplied. Service should be restored to these affected load points as quickly as possible through network reconfiguration. An efficient technique is presented in this paper for this purpose. Network reduction and strategy testing the voltage and current constraints are the main contributions of this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10B
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• pp.644-654
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• 2007

ZigBee is one of wireless communication standards and many applications based on Zigbee have been developing for commercial applications. Most of those applications require links to Internet like Zigbee service gateways. However, ZigBee service gateway should provides following functions to be effectively utilized itself: translation of messages between diverse ZigBee application profiles and message formats used in Internet, addition/removal of a new ZigBee service without stopping existing services according to addition/removal of a Zigbee node, and no transmission of unwanted packets to ZigBee network. Therefore, this paper proposes a new type of ZigBee Service Gateway, called ZiGate to provide the functions. The proposed ZiGate is capable of re-configurating message translation modules required in case of addition/removal of nodes and doesn't transmit unnecessary packets to the ZigBee networks by synchronizing itself with ZigBee network. And ZiGate provides translation modules between messages defined in Zigbee application profiles and both text-based and binary-based messages used in Internet. In this paper we implements the ZiGate and evaluates it on the test bed. This evaluations show that the proposed ZiGate works efficiently.

• The KIPS Transactions:PartA
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• v.15A no.3
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• pp.151-154
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• 2008

A middleware in grid computing environment is required to support seamless on-demand services over diverse resource situations in order to meet various user requirements [1]. Since grid computing applications need situation-aware middleware services in this environment. In this paper, we propose a semantic middleware architecture to support dynamic software component reconfiguration based fault and service ontology to provide fault-tolerance in a grid computing environment. Our middleware includes autonomic management to detect faults, analyze causes of them, and plan semantically meaningful strategies to recover from the failure using pre-defined fault and service ontology trees. We implemented a referenced prototype, Web-service based Application Execution Environment(Wapee), as a proof-of-concept, and showed the efficiency in runtime recovery.