• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.715-724
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• 2023

Solar energy forecasting is essential for (1) power system planning, management, and operation, requiring accurate predictions. It is crucial for (2) ensuring a continuous and sustainable power supply to customers and (3) optimizing the operation and control of renewable energy systems and the electricity market. Recently, research has been focusing on developing solar energy forecasting models that can provide daily plans for power usage and production and be verified in the electricity market. In these prediction models, various data, including solar energy generation and climate data, are chosen to be utilized in the forecasting process. The most commonly used climate data (such as temperature, relative humidity, precipitation, solar radiation, and wind speed) significantly influence the fluctuations in solar energy generation based on weather conditions. Therefore, this paper proposes a hybrid forecasting model by combining the strengths of the Prophet model and the GRU model, which exhibits excellent predictive performance. The forecasting periods for solar energy generation are tested in short-term (2 days, 7 days) and medium-term (15 days, 30 days) scenarios. The experimental results demonstrate that the proposed approach outperforms the conventional Prophet model by more than twice in terms of Root Mean Square Error (RMSE) and surpasses the modified GRU model by more than 1.5 times, showcasing superior performance.

• Journal of Information Technology and Architecture
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• v.10 no.2
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• pp.181-195
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• 2013

This study is to investigate into the factors that influence the use of a military logistics information system in Korean army. We developed the research model based on DTPB (Decomposed Theory of Planned Behavior) because the DTBP is an appropriate model in a mandatary using environment through the study of previous technology-acceptance models. A questionnaire survey was conducted with Korean army solders and civilian components who use the army logistics information system and 266 valid questionnaires are recovered. The collected data were analyzed by SPSS and AMOS. The results show that perceived usefulness and ease of use did not affect the attitude of the use intention. The influence of colleagues and upper class officers was all satisfactory and computer self-efficiency affected perceived control of behavior. The results of this study will contribute to the further use of the military logistics information system and future development strategy.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.507-510
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• 2006

본 논문에서는 모바일 DRM(Digital Rights Management) 상의 멀티미디어 파일에 적용할 수 있는 상황인식 기반의 사용제어 모델을 제안한다. 특히, 위치 및 시간 등의 상황 정보에 기반하여 모바일 콘텐츠에 대한 접근 및 사용을 제어하는 '동적인 역할기반 접근제어'(dynamic role-based access control)를 지원하는 프로토타입 시스템을 임베디드 보드 상에서 구현하여 테스트하였다.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.72.1-72.1
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• 2019

The Giant Magellan Telescope Organization (GMTO) is developing the GMT Software Development Kit (SDK) for the Observatory Control System (OCS). The SDK models a subsystem of the GMT using a Domain Specific Language (DSL) which can generate a skeleton code and validates the availability of the model automatically. The OCS includes a Device Control System (DCS) and all the devices are connected with the DCS via EtherCAT. The DCS has a component (Hardware Adapter) to communicate with EtherCAT slaves. In this presentation, we demonstrate the modeling process and describe the importance and usage plan of the SDK.

• Journal of Information Technology Applications and Management
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• v.11 no.2
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• pp.167-178
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• 2004

Different from traditional development methodologies like waterfall model, the CBD (component based development) methodology relies on a building block approach in the design and development of information system. The audit procedure and checklist for the traditional IS development methodology are required to be modified to be suitable for CBD. This research reviewed IS audit guidelines for the existing development process and analyzed multiple projects that employed the by component based development process. For the purpose of this study, we chose a governmental project and a next-generation IS project of a financial agency as sample cases. By comparing existing IS audit checklists and items actually reviewed in audit projects, this study identified appropriate check items for the CBD-centric audit program. New items were proposed as additional items such as project control in management phase, usage case and conceptual model establishment, component evaluation and design, in implementation phase, and so forth. The result of the research provides new guidelines for the audit CBD projects for the purposed of increased efficiency and qualify of application development projects.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.1
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• pp.1-9
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• 2007

At present various methods relating resource access control in grid environment are being studied. Most of the access authorization to grid resource is designed fit to the attributes and the role of user. But resource access control is to be made in the respect of business model to activate grid. Therefore this study suggests a model that can operate resource access control driven by grid accounting information. On the base of collection of accounting information about grid job, processing cost is yielded. If the user's available fund is less than processing cost, it gets to control grid job by the resource access control policy. Finally when grid job is completed, user is assigned to pay the charges for using resource of supplier. Then resource provider gets to supply stable resource in grid by participating it voluntarily to use idle resource. This study is esteemed to realize utility computing environment correspondent to economic principle by ensuring resource access policy of organizations which participate in grid.

• Architectural research
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• v.19 no.3
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• pp.71-77
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• 2017

Dynamic pricing refers to a system in which a tariff varies, according to a level of charging and applied time depending on time change. The power billing system used in the Korean Electric Power Corporation (KEPCO) is based on time of use (TOU) pricing, which is one of the dynamic pricing systems. This paper aimed to determine the operational results of a variable refrigerant flow system, to which a new control algorithm was applied, in order to respond to dynamic pricing, in summer and the utility of the new control. To do this, real measured data was acquired from a VRF system installed in a building for educational purposes, where dynamic pricing was applied for about 100 days during summer time. At the maximum load operation time period in TOU, the new control minimized operation within the indoor comfort range, an increase in refrigerant evaporation temperature in the indoor unit and the number of revolutions in a compressor in the outdoor unit was limited. As a result, power usage was decreased by 11%, and the operational cost by 14.6%. Furthermore, measurement results using the Predicted Mean Vote (PMV) model, that represented satisfaction of thermal environment, showed that 82.8% to 90.4% of the occupants of the building were satisfied during operation when the new control was applied.

• Journal of the Korean Solar Energy Society
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• v.36 no.4
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• pp.31-40
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• 2016

The demands for photovoltaic systems on a large scale have grown dramatically and require new technologies to get the high efficiency and reliable operations of power conversion systems. These needs can be realized by the cost-effective and high performance digital revolutions and faster semiconductor switching devices. However, the new power systems have been more sophisticated and their reliability becomes critical issues. In this paper, a new fault-tolerance power conversion scheme for the photovoltaic systems is proposed. The proposed fault-tolerant scheme is able to supply energy from solar panels to loads intermittently in spite of a front boost converter open failure, and its voltage and current controllers are designed to improve the transient performance by using an average model design scheme. The proposed approach is verified both by simulations. The results will enable more timely and wide usage of alternative/renewable energy systems resulting in increased energy security.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.9
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• pp.484-490
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• 2015

The winter stack effect that occurs in vertical construction passages such as the stairwell or elevator shaft of a high-rise building negatively affects living environments, energy usage, and personal safety; therefore, a mitigation of the stack effect is required to improve building conditions. Recently, circulation-type facilities that comprise the usage of air blowers and vertical ducts were proposed as part of a mechanical approach to quantitatively control the stack effect. In this study, these circulation-type facilities were installed in a building stairwell and the performance of the device was evaluated during its operation. A numerical-analysis result was obtained under the test conditions using a network-model-based, numerical-analysis method, and the result was then used for a comparison with the test result.

• International Journal of Contents
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• v.15 no.1
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• pp.39-51
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• 2019

Spontaneous speech provides rich information defining the linguistic characteristics of individuals. As such, computational analysis of speech would enhance the efficiency involved in evaluating patients' speech. This study aims to provide a method to differentiate the persons with and without aphasia based on language usage. Ten aphasic patients and their counterpart normal controls participated, and they were all tasked to describe a set of given words. Their utterances were linguistically processed and compared to each other. Computational analyses from PCA (Principle Component Analysis) to machine learning were conducted to select the relevant linguistic features, and consequently to classify the two groups based on the features selected. It was found that functional words, not content words, were the main differentiator of the two groups. The most viable discriminators were demonstratives, function words, sentence final endings, and postpositions. The machine learning classification model was found to be quite accurate (90%), and to impressively be stable. This study is noteworthy as it is the first attempt that uses computational analysis to characterize the word usage patterns in Korean aphasic patients, thereby discriminating from the normal group.