• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.644-651
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• 2014

The renewable energy system and the real-time pricing can provide the significant economic advantage for end-user of residential house. However, according to recent studies, high initial cost of renewable energy system such as photovoltaic (PV) system and lack of suitable load control methods adjusting electric power consumption in response to time-varying price are regarded as the major obstruction for introduction of renewable energy system and real-time pricing in residental household. In this paper, we propose automated optimal load control strategy which aim to achieve not only minimizing the electricity cost but also the increase in the utilization rates of PV generation power of residential PV house in real-time pricing environment. Simulation results show that our proposed optimal load control strategy leads to significant reduction in the electricity costs and increase in the utilization rates of power generated by PV system in comparison with the conventional PV house. Therefore, the proposed optimal load control strategy can provide more economic benefit to end-user.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.434-441
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• 2001

The concept of network memory was introduced for the efficient exploitation of main memory in a cluster. Network memory can be used to speed up applications that frequently access large amount of disk data. In this paper, we present a memory a management algorithm that does not require prior knowledge of access patterns and that is practical to implement under the web server cluster, In addition, our scheme has a good user response time for various access distributions of web documents. Through a detailed simulation, we evaluate the performance of our memory managment algorithms.

• Journal of the Korean Geophysical Society
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• v.7 no.4
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• pp.237-245
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• 2004

Series of basic experiments for current density calibration by user process and for density calibration using geophysical model borehole were made. We tried to find the sonde response characteristics for current calibration using water and aluminium field jig, and using the equation of half life of 137Cs source. The result of calibration test made in a geophysical model borehole built first in Korea shows a perfect linear calibration equation. By adopting this calibration equation we could estimate the limitation as well as possibility of current density calibration by user process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.90-95
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• 2018

The Korean Peninsula is no longer safe from volcanic disasters. Therefore, the Korean government has been developing a spatial information-based system implementation technology since 2014. VDRS (Volcanic Disaster Response System), which is the result of the technology, was implemented in 2016 as Phase I. Since then, phase II implementation technology has been developed for an advanced system reflecting the user's requirements. To advance the system, redesign architecture is essential. This paper examined the redesign application architecture for an advanced VDRS. First, existing application architecture, which was implemented in phase I, was analyzed. Second, the user's requirements for advanced VDRS were analyzed. The analyzed user's requirements were categorized as a transforming service oriented to a business-oriented architecture, improving accuracy, and expanding the spatial range and target disaster. Third, application architecture was redesigned based on gap analysis between the existing architecture and user's requirements. The results of the proposed redesign architecture are presented as the application system structure and description of the application function based on owner's point of view in the enterprise architecture. The results of this paper can be used to derive the application module design and provide a detailed description of the application module based on the designer's point of view. Further research focused on structuring the HW/SW architecture will be required for system implementation.

• Science of Emotion and Sensibility
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• v.13 no.1
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• pp.129-146
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• 2010

System response times(SRTs) are getting important while increasing the function of system. In the past, most research studied SRTs on situation of computer usage. There are lacking the research on simple domain. This study focuses on behavioral and emotional effect on situation of cell phone usage(experience 1; independent variables: degree of SRTs, dependent variables: behavioral and emotional evaluation). And this study investigates the behavioral and emotional effect in same SRTs on different situation(experience 2; independent variables: degree of SRTs, usage mode, dependent variables: behavioral and emotional evaluation, stress, mental strain). The result indicated that long SRTs increased problem solving time and negative emotion. User evaluated the system differently according to usage mode after they performed the same task. In other word, if user had a strong goal, then they felt more negative emotion and mental effort than the user don't have a strong goal. In the goal mode group, it was important there are being of delay or not. This study demonstrated that SRTs and usage mode influence user's emotion and behavior performance in same task.

• Journal of Nutrition and Health
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• v.38 no.2
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• pp.180-189
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• 2005

The purposes of this study were 1) to analyze the effect of the ERP quality (system quality, information quality, service quality) on the performance (end user satisfaction, user's performance, system utilization) of business, 2) to conduct the causal-effect analysis between outcome variables (user's satisfaction, user's performance, system utilization) of ERP in the contract foodservice management company. The questionnaires were distributed to 260 end users (dietitians, foodservice management managers) in charge of managing the institutional foodservice such as the office (government agencies, factories), schools (universities, middle and high school) and hospitals which were managed by contract foodservice management company 'C' in Seoul and Kyunggi. The surveys were performed from July 26, 2004 to July 30. 2004. Two hundred and fifty (250) questionnaires were responded (response rate: 96.2%). The statistical analysis was conducted using SPSS Win (11.5). And the descriptive analysis, factor analysis, reliability test, pearson correlation, simple and multiple regression analysis were performed. The results showed that among the 3 factors (system quality, information quality, service quality), the system quality and information quality were proved to have an effect on the user's satisfaction and user's performance significantly (p < .05). The influence of ERP quality (system quality, information quality, service quality) on system utilization were testified to be statistically significant (p < .05). The user's performance were affected significantly by system utilization (p < 0.001) and end user's satisfaction (p < 0.001). As a conclusion, to improve user satisfaction, which is the ultimate performance variable of an ERP system, high quality of an ERP system is the pre-requisite. And the user satisfaction and performance of business would be higher with the better quality ERP system. When constructing ERP system for the contract foodservice management company, we should improve system utilization and user satisfaction altogether so that user's performance could be ultimately enhanced and we should make efforts to enhance the quality level of ERP. (Korean J Nutrition 38(2): 180～189, 2005)

• Journal of the Korea Society of Computer and Information
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• v.21 no.5
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• pp.127-133
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• 2016

In this paper, an intelligent dimming control system is designed and implemented with the human visual response function using CDS sensor, PIR sensor and temperature sensor, etc. The proposed system is designed to detect a moving object by PIR sensor and to control the LED dimming considering the human visual response. Also, the dimming of LED light can modulate on the app, and simultaneously control dimming in real-world environments with smart phone app. A high-temperature warning or a fire hazard information is transmitted to user's smart phone according to sensor values and Data graph are provided as part of data visualization. Connecting the hardware controller, the proposed intelligent smart dimming control system is expected to contribute to the power reduction interior LED, smart grid building and saving home combining with internet of things.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1869-1875
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• 2008

Recently, a direct data-driven synthesis of a proportional integral derivative(PID) controller for a linear time-invariant(LTI) plant was presented in [1]. The authors showed that a complete set of PID controllers achieving robust performance and stability can be calculated directly from frequency response(FR) data without an identified transfer function model. However, it is not convenient to use this method because it requires complicated numerical algorithms to find specific frequencies which are solutions of an identical equation. The method also requires determination of the boundary of the controller's parameters from a finite set of FR data. In this paper, we present the development of a user-friendly Matlab toolbox based on the method in [1]. This toolbox allows us to obtain a complete three-dimensional(3-D) graphical solution of PID controllers that meet multiple design objectives. Several examples are given to demonstrate the use of the toolbox.

• 한국데이터정보과학회:학술대회논문집
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• 2006.11a
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• pp.59-69
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• 2006

Pearson's correlation coefficient and Vector similarity are generally applied to The users' similarity weight of user based recommender system. This study is needed to find that the correlation coefficient of similarity weight is effected by the number of pair response and significance probability. From the classified correlation coefficient by the significance probability test on the correlation coefficient and pair of response, the change of MAE is studied by comparing the predicted precision of the two. The results are experimentally related with the change of MAE from the significant correlation coefficient and the number of pair response.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.3
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• pp.130-138
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• 1993

A mechanism for collision detection in general animation system is necessary to prevent the interpenetration among multiple objects. On the other hand, a dynamic simulation system which is a part of animation system simulates realistic motions using dynamics after the collision, which is called collision response. In this paper, a method for reducing the CPU time for collision detection by removing redundant calculations and object sorting is proposed. A dynamic simulation system including collision detection and response function was implemented to demonstrate the proposed methods, where the input data as elasticity, friction, gravity, object shape, external force and external torque are given by the user. The system simulates motions of multiple objects using dynamics, and generates the wireframe display.