• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.42-44
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• 2005

데이터 모델링의 객체 지향적인 접근은 변전소 자동화 시스템의 설계 및 구현에 객체의 재활용과 객체 정보의 숨김과 같은 효율성을 제공한다. 변전소 자동화 시스템을 위한 IEC 61850 표준은 이러한 객체 지향 개념에 기반한 데이터 모델링을 IEC 61850 표준문서의 파트 7에서 제시하였다. 표준은 데이터를 교환하는 가장 작은 기능으로써 Logical Node(LN)를 모델링 하였고 본 논문에서는 LN을 비롯한 여러 객체 지향 데이터 모델들을 설명하고 분석하였다.

• Proceedings of the KIEE Conference
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• 2006.05a
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• pp.78-82
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• 2006

The Partial Discharge Monitoring System is technology which is available to measure & analysis the partial discharge of Power equipment. This technology is in the limelight as a pre-forecast system of equipment defect but there are some problems like no protocol standard, layered network management and the limitation of physical size. This paper presents whole system structure includes engineering centers, LN(Logical Node) to apply PDMS for, base-digital substation system, ICE61850 compatible Condition Monitoring &Diagnosis (CMD), Local Unit(LU), Intelligent Electronic Device (IED) for the solution scheme of these limitations.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.134-135
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• 2008

현재 전 세계적으로 IEC61850 프로토콜을 적용한 제품 및 그 목적에 맞게 Interoperability를 구현하려는 노력이 진행되고 있으며 (주)효성은 자체 설계한 154kV 변압기용 Logical Node를 이용하여 상용화된 Configuration Tool로 시스템을 설계하여 IEC61850 기반 Local Unit(LU)을 개발하였고 현재 판매되고 있는 타사 계전기 제품(ABB, SIEMENS)을 이용하여 IEC61850 기반 데모 시스템을 구성하여 LU 및 타사 제품간의 데이터 교환이 이루어짐을 확인할 수 있다.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.2
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• pp.89-97
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• 2017

The substation is a critical node in the power network where power is transformed in the power generation, transmission and distribution system. The IEC 61850 is a global standard which proposes efficient substation automation by defining interoperable communication and data modelling techniques. In order to achieve this level of interoperability and automation, the IEC 61850 (Part 6) defines System Configuration description Language (SCL). The SCL is an XML based file format for defining the abstract model of primary and secondary substation equipment, communications systems and also the relationship between them. It enables the interoperable exchange of data during substation engineering by standardizing the description of applications at different stages of the engineering process. To achieve the seamless interoperability, multi-vendor devices are required to adhere completely to the IEC 61850. This paper proposes an efficient algorithm required for verifying the interoperability of multi-vendor devices by checking the adherence of the SCL file to specifications of the standard. Our proposed SCL validation algorithm consists of schema validation and other functionalities including information model validation using UML data model, the Vendor Defined Extension model validation, the User Defined Rule validation and the IED Engineering Table (IET) consistency validation. It also integrates the standard UCAIUG (Utility Communication Architecture International Users Group) Procedure validation for quality assurance testing. Our proposed algorithm is not only flexible and efficient in terms of ensuring interoperable functionality of tested devices, it is also convenient for use by system integrators and test engineers.

• The Plant Pathology Journal
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• v.17 no.4
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• pp.222-226
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• 2001

In 1997, 103 isolates of Verticillium were obtained from roots and stems of tomato plants showing wilt symptoms in greenhouses in eight areas of Korea. Out of these isolates, 75 were edintified as V. dahliae while 28 were identified as V. albo-atrum based on their morpho-logical and cultural characteristics. Both Verticillium species produced colonies with conidiophores, which were more or less erect, hyaline, with verticillate branches, and with 3-4 phialides at each node. V. dahliae produced microsclerotia, while V. albo-atrum produced resting dark mycelium. Optimum temperatures for mycelial growth of V. dahliae and V. albo-atrum on PDA were 22 and $26^{\circ}$, respectively. Mycelial growth of V. albo-atrum was slower than that of V. dahliae. Pathoge-nicity tests revealed that tomato cvs. Zuikoh No. 102, Kyoryokubeiju No. 2, Zuiken, Kagimuza, and Momotaro were susceptible to V. albo-atrum, while cvs. Zuikoh No. 102 and Kyoryokubeiju No.2 were susceptible to V. dahliae.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.320-322
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• 2006

현재 선진국에서는 대규모 정전 사태에 대비할 수 있는 광역 감시 및 보호 시스템이 연구되고 있고 실제 필드에 적용되어 사용중인 시스템도 있지만 통신 환경의 호환성등 제한 조건이 발생되고 있다. 이에 변전소 자동화 국제표준 프로토콜인 IEC 61850을 적용하여 기존 광역 감시 시스템들의 통신 호환성의 제약을 해결하고자 하였다. 국제 표준인 IEC 61850 프로토콜은 변전소 자동화 시스템을 위해 표준화된 객체 모델을 기반으로 이루어지고 있지만 전력설비의 다양한 모델을 완벽하게 객체화하기 위하여 TC57위원회에서는 지속적으로 객체 모델 수정 및 추가 작업을 진행중이다. 본 연구는 광역 전력계통 감시에 필요하지만 IEC TC57에서 표준화되지 않은 전압안정도를 위한 객체 모델을 제시하였고, 객체에 대한 Logical Node(이하 LN)과 Common Data Class(이하 CDC)를 구성하였다. 이 LN은 LS산전의 지능형 전력 시스템 정보 장치(i-PIU: intelligent Power system Information Unit, PMU: Phasor Measurement Unit)에 적용되고 있다.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1319-1327
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• 2015

As wind power farm (WPF) installations continue to grow, monitoring and controlling large-scale WPFs presents new challenges. In this paper, a hierarchical network architecture is proposed in order to provide remote monitoring and control of large-scale WPFs. The network architecture consists of three levels, including the WPF comprised of wind turbines and meteorological towers, local control center (LCC) responsible for remote monitoring and control of wind turbines, and a central control center (CCC) that offers data collection and aggregation of many WPFs. Different scenarios are considered in order to evaluate the performance of the WPF communications network with its hierarchical architecture. The communications network within the WPF is regarded as the local area network (LAN) while the communication among the LCCs and the CCC happens through a wide area network (WAN). We develop a communications network model based on an OPNET modeler, and the network performance is evaluated with respect to the link bandwidth and the end-to-end delay measured for various applications. As a result, this work contributes to the design of communications networks for large-scale WPFs.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.210-212
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• 2000

In this paper, we present a comcurrency control scheme over the index structure in main memory databases using multiversion mechanism, and implement it on T-tree. As a well-known idea for comcurrency control, multiversion allows multiple transactions to reat and write different versions of the same data item, each transaction sees a consistent set of versions for all the data items it accesses[1]. Logical versioning and physical versioning techniques are used to keep versions of data item and versions of index node respectively. The main features of this multiversion indexing approach are (1)update operations and rotations on T-tree can take place concurrently, (2)the number of locking and latching requirement is sharply reduced because read-only transactions do not obtain any locks or latches and update transactions obtain latches only when actually performing the update, (3)it reduces storage overhead for tracking version and reclaims storage in time, and (4)it provides complete isolation of read-only transactions from update transactions, so the read-only transactions can get response information without any block.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.789-800
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• 2014

In this paper, we propose a cooperative protocol of relay-based WUSB/DRD and WLP device in WSS of ship area WiMedia environment. For this purpose, we investigate a RNT table configuration and algorithm of RNS relay node used in relay-based cooperative communication. Then, we describe a device that makes up WLP network and propose a cooperative protocol for WUSB/DRD/WLP device communication. The proposed cooperative protocol can communicate with WUSB/DRD/WLP devices by using standard DRP reservation and WUSB DRP reservation.

• Journal of Semiconductor Engineering
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• v.2 no.3
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• pp.136-141
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• 2021

This paper analyzes the tree expansion for multiple-input multiple-output (MIMO) detection in the viewpoint of hardware implementation. The tree expansion is to calculate path metrics of child nodes performed in every visit to a node while traversing the detection tree. Accordingly, the tree-expansion unit (TEU), which is responsible for such a task, has been an essential component in a MIMO detector. Despite the paramount importance, the analyses on the TEUs in the literature are not thorough enough. Accordingly, we further investigate the hardware complexity of the TEUs to suggest a guideline for selection. In this paper, we focus on a pair of major ways to implement the TEU: 1) a full parallel realization; 2) a transformation of the formulae followed by common subexpression elimination (CSE). For a logical comparison, the numbers of multipliers and adders are first enumerated. To evaluate them in a more practical manner, the TEUs are implemented in a 65-nm CMOS process, and their propagation delays, gate counts, and power consumptions were measured explicitly. Considering the target specification of a MIMO system and the implementation results comprehensively, one can choose which architecture to adopt in realizing a detector.