• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.43-46
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• 2010

전력산업분야는 스마트그리드 표준체계 및 고도화된 정보통신 인프라의 도입과 보안 그리고 분산전력 등에 대한 신기술 도입에 의해서 급격한 변화기를 맞이하고 있다. 현재 미국과 EU에서는 세계시장을 겨냥해서 스마트그리드의 국제표준화를 주도하고 있으며, 제3세계에서는 전력설비 시장의 지속적 성장이 예상되고 있다. 이에 국내에서도 국제 경쟁력 확보 및 신성장동력 창출을 목표로 연구가 진행 중이다. 전력체계의 운영망과 별개의 시험망 구성이 필요하며, 그 시험망을 통한 검증을 위해 시험망내 표준규격의 통신환경의 설계 및 기능검증은 매우 중요한 요소이다. 본 논문에서는 시험평가망 구성이후 평가를 위해 사용할 수 있는 주요 Component의 설계과정 중의 일부인 IEC 61850기반의 MMS 통신 환경구성 및 기능검증을 위한 연구결과에 대해 설명한다.

• Nuclear Engineering and Technology
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• v.37 no.2
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• pp.139-150
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• 2005

A robust control design procedure for a nuclear reactor has been developed and experimentally validated on the Penn State TRIGA research reactor. The utilization of the robust controller as a component of an autonomous control system is also demonstrated. Two methods of specifying a low order (fourth-order) nominal-plant model for a robust control design were evaluated: 1) by approximation based on the 'physics' of the process and 2) by an optimal Hankel approximation of a higher order plant model. The uncertainty between the nominal plant models and the higher order plant model is supplied as a specification to the ,u-synthesis robust control design procedure. Two methods of quantifying uncertainty were evaluated: 1) a combination of additive and multiplicative uncertainty and 2) multiplicative uncertainty alone. The conclusions are that the optimal Hankel approximation and a combination of additive and multiplicative uncertainty are the best approach to design robust control for this application. The results from nonlinear simulation testing and the physical experiments are consistent and thus help to confirm the correctness of the robust control design procedures and conclusions.

• Journal of Information Technology Applications and Management
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• v.12 no.3
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• pp.27-39
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• 2005

The Semantic Web has increased the interest in ontologies recently Ontology is an essential component of the semantic web and continues to change and evolve. We consider versions management schemes in ontology. We study a set of changes based on domain changes, changes in conceptualization, metadata changes, and temporal dimension. Our change specification is represented by a set of changes. A set of changes consists of instance data change, structural change, and identifier change. In order to support a query in ontology versions, we consider temporal dimension includes valid time. Ontology versioning brings about massive amount of versions to be stored and maintained. We present the ontology versions management schemes that are 1) storing all the change sets, 2) storing the aggregation of change sets periodically, and 3) storing the aggregation of change sets using an adaptive criterion. We conduct a set of experiments to compare the performance of each versions management schemes. We present the experimental results for evaluating the performance of the three version management schemes from scheme 1 to scheme 3. Scheme 1 has the least storage usage. The average response time in Scheme 1 is extremely large, those of Scheme 3 is smaller than Scheme 2. Scheme 3 shows a good performance relatively.

• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.637-644
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• 2001

EJB, providing specification for development and deployment of component based application, permits distributed development as central element of J2EE environment that manages automatically transaction management, persistence, concurrency control that are the most complicated work in enterprise environment. In this paper, we wish to resolve DAO's transaction logic complexity and performance reduction of system in the EJB based legacy system. Therefore, this paper describes the design and implementation of IDAO that applies Iterator pattern. IDAO gets effect that reduces complexity of transaction logic, system overload by database connection, and reduction of performance through container managed transaction.

• Journal of Information Technology Services
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• v.9 no.2
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• pp.179-192
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• 2010

In order to resolve the problems of traditional Enterprise Application Integration (EAI) for system integration and to establish flexible enterprise IT environments, Enterprise Service Bus(ESB) which have distributed architecture and support Service Oriented Architecture(SOA) has introduced. Particularly, JBI which developed by the Java Community Process is most widely used to implement ESB for advantages of Java technology. In ESB based on JBI, reliable message delivery is very important to ensure stability of services and systems because it is a message driven architecture. But, it is difficult to verify messages and trace messages when system fault or service error occurred because JBI specification is not enough to address them. In this paper we has proposed the Message Monitoring Framework for JBI-based ESBs which for using in monitoring messages efficiently. It provides foundations for gathering and tracing message-related information about component installation, message exchange, service deploy by using proxy-based change tracking and delegation mechanism for data processing. The proxy which used in our solutions collects data about message automatically when it changed, and the delegation mechanism provides users flexibility for data processing. Also, we describe the performance evaluation results of our solution which is acceptable. We expect to it enables users to ensure reliability and stability of the JBI-based ESB by systematic monitoring and managing messages being used to interact among components.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1445-1452
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• 2016

Recently Mobile Software Applications are developed in various languages and stored in App Store. App Users selectively use appropriate apps for the owned hardware. In other words, it depends on the kinds of operating systems of the apps whether to use or not to use the applications in various languages. The apps should be differently implemented according to the kind of the user's device, though they provide the same functions. To solve these problems, it is necessary to define an independent function specification method which is not dependent to a specific system environment. In this paper, the Mobile Application Developing Framework is suggested, which incorporates all of the development process. Standardized models are proposed which can be used in the analysis and design steps. In implementation phase, a technique for cross framework design is suggested so as to implement a platform dependent mobile app.

• 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.

• Journal of Navigation and Port Research
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• v.43 no.5
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• pp.296-301
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• 2019

The Electronic Chart Display and Information System (ECDIS) is an integral component of ship navigation equipment, that enables mariners to view Electronic Navigational Charts (ENC). Recently, it has become possible to transport freight and energy resources via the Northern Sea Routes (NSR) as global warming has been accelerating. However, ice can impact all types of ships and the potential danger that ice poses is significant. Until now, ice, consistently proven to be one of the most dangerous threats impacting navigation in ice-covered regions, has its detailed standard in the specification of the International Hydrographic Organization (IHO) for ECDIS. The investigations described in this paper were conducted to assess the advantages and problems of the display of ice objects on ECDIS. The experiments were conducted by using the Geographic Information System (GIS) to perform ice objects with their corresponding colors and symbols. Implementation of the standardized appearance of ice objects can enable mariners to access the ice condition of seas in a short time before navigating a safe passage through potentially treacherous waters. However, remain issues that must be overcome for data on ice to be fully compatible with an ECDIS system.

• Journal of Internet Computing and Services
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• v.24 no.1
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• pp.9-15
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• 2023

Single-Page Application(SPA) requires data transformation for communication with RESTful API. The Backend for Frontend(BFF) pattern handles this transformation in the server, but there is some problem that increases the number of communication and makes development and distribution difficult. In this study, we propose an architecture that maps the ViewModel of SPA and the model of RESTful API directly in SPA. The proposed architecture automatically generates a mapping model between the RESTful API model and the ViewModel using the OpenAPI specification, which is the document model of the RESTful API. The data transfer component of SPA automatically converts RESTful API data and ViewModel using the created model. As a result of comparison with the existing BFF method through case study, the proposed architecture showed higher development productivity than BFF, and as a result of load tests, it recorded about 6% lower server CPU occupancy compared to BFF.

• Journal of applied mathematics & informatics
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• v.40 no.1_2
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• pp.351-370
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• 2022

The design of mechanical structures aims to meet criteria, together with the safety of operators and lives in the vicinity of the equipment. Thus, there are several cases that meeting the desired specification causes the mechanical device to perform unstable and, sometimes, chaotic behavior. In these cases, control methods are applied in order to stabilize the device when in operation, aiming at the physical integrity of the component and the device operators. In this work, we will develop a study about the influence of a controller applied in a non-ideal capsule system operating with uncertain parameters, being non-existent in the literature. For this, two initial conditions were used: one that the capsule starts from rest and another that it is already in motion. Thus, the effectiveness of the controller can be assessed in both initial conditions, restricting the movement of the internal vibration-impact system to the capsule.