• 정보보호학회논문지
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• 제23권4호
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• pp.639-653
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• 2013

스마트 그리드는 기존 전력망에 IT 기술을 접목하여 에너지 효율을 최적화하는 차세대 지능형 전력망으로 미국, 유럽, 일본 등 전 세계적으로 기술개발이 이루어지고 있으며 실증사업을 추진하고 있다. 최근 스마트 그리드에 대한 공격 사례가 증가되고 있으며 개인정보의 사용 및 유출의 피해가 높아지고 있다. 전력망이 더욱 복잡해지고 상호 연결됨에 따라 보안 분석과 평가에 대한 노력이 점차 중요해지고 있다. 본 논문에서는 스마트 그리드의 핵심 기술인 AMI(Advanced Metering Infrastructure)의 공격과 공격에 대한 대응책을 ACT(Attack Countermeasure Tree)를 이용하여 모델링 하였다. 보안 분석은 확률이 있는 경우와 확률이 없는 경우로 나누어서 수행하였다. 이러한 모델을 가지고 SHARPE(Symbolic Hierarchical Automated Reliability and Performance Evaluator)로 구현하여 다양한 경우의 확률과 ROA, ROI, Structure Importance, Birnbaum Importance에 대해 계산하였다.

• 한국식생활문화학회지
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• 제16권5호
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• pp.423-430
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• 2001

The facts of job satisfaction and their perceived importance among elementary school foodservice dietitians were assessed. The survey instrument consisted of three parts: the job satisfaction survey was used to measure facets of job satisfaction and the level of total satisfaction; perceived importance questions for corresponding job facets; and demographic items. A survey of school food service operations was undertaken and detailed information was collected from 170 dietitians. The collected data were processed using the SPSS package program for descriptive analysis and analysis of valiance. School foodservice dietitians' importance and satisfactions scores on their job and working environment were 4.25 and 2.83, respectively. The respondents rated the subscales of 'communication' and 'nature of work' the highest and the subscales of 'pay' and 'working environment' the lowest The results of facet satisfaction scores and corresponding perceived importance scores were paired to be plotted on the Importance-Performance Analysis Grid. IPA grid was used to provide a strategy for food service managers to counteract dietitian dissatisfaction.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1248-1257
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• 2014

Overhead transmission lines are crucial components in power transmission systems. Well-designed maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

• 한국병원경영학회지
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• 제14권2호
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• pp.21-40
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• 2009

The importance-performance analysis (IPA) is a widely used analytical technique that produces a priority of managerial attention for the customer satisfaction. This study attempted to compare various different approaches of IPA such as direct and indirect measurement of importance, and traditional four quadrants grid model and diagonal grid model of IPA. Data on 17 inpatient service quality attributes were collected from 234 inpatients of a general hospital. Eight IPA grids were produced to compare the result of each model. Based on the study results the strength and weakness of each model were discussed, and a set of recommendations for practical application of the IPA in hospital settings was suggested.

• 한국인공지능학회지
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• 제11권2호
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• pp.1-6
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• 2023

This paper presents a comprehensive scheme for assessing the importance of multiple microgrids (MGs) network that includes distributed energy resources (DERs), renewable energy systems (RESs), and energy storage system (ESS) facilities. Due to the uncertainty of severe weather, large-scale cascading failures are inevitable in energy networks. making the assessment of the structural vulnerability of the energy network an attractive research theme. This attention has led to the identification of the importance of measuring energy nodes. In multiple MG networks, the energy nodes are regarded as one MG. This paper presents a modified PageRank algorithm to assess the importance of MGs that include multiple DERs and ESS. With the importance rank order list of the multiple MG networks, the core MG (or node) of power production and consumption can be identified. Identifying such an MG is useful in preventing cascading failures by distributing the concentration on the core node, while increasing the effective link connection of the energy flow and energy trade. This scheme can be applied to identify the most profitable MG in the energy trade market so that the deployment operation of the MG connection can be decided to increase the effectiveness of energy usages. By identifying the important MG nodes in the network, it can help improve the resilience and robustness of the power grid system against large-scale cascading failures and other unexpected events. The proposed algorithm can point out which MG node is important in the MGs power grid network and thus, it could prevent the cascading failure by distributing the important MG node's role to other MG nodes.

• 산업공학
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• 제24권4호
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• pp.379-386
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• 2011

The importance of renewable energy technology is discussed and next generation power transmission networks, which is called the smart grid, are constructed in developed countries. However for construction and operation of the smart grid, it is required not only to develop the electrical power generation technologies and transmission equipments but also to study systematic analysis and optimization for design and operation of the smart grid. In this paper we study electrical power trade in the smart grid using operations research models and simulation methods. We also consider future electrical power exchange markets in Korea and build four scenarios and the related optimization and simulation models, which reflect electrical power transaction pricing strategies of stake-holders. We can also simulate electrical power exchange market and analyze the results of electrical power trading, which can give us some insights for future electrical power exchange market.

• 한국태양광발전학회지
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• 제6권1호
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• pp.86-91
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• 2020

Nepal is among the richest in terms of water resource availability and it is one of the most important natural resources of the country. Currently, 72% of the population is electrified through the national grid system. The power generation mix into the grid is hydro dominated with minor shares generated from solar and thermal (accounts for less than 1%). To achieve sustainable development in the power sector it is essential to diversify power generation mix into the grid. Knowing the facts, the government has a plan to achieve a 5-10% share of power generation from solar and mix it into the grid system. Solar is the second most abundant, prominent and free source of renewable in the context of Nepal. This study mainly focuses on the grid-connected solar system, its importance, present status, government efforts, and its need. It is based on the review of literature, news published in national newspaper online news and international organization's report.

• 한국안전학회지
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• 제39권1호
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• pp.70-81
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• 2024

With heavy rainfall due to extreme weather causing increasing damage, the importance of urban flood forecasting continues to grow. To forecast urban flooding accurately and promptly, a sewer network and surface grid with appropriate detail are necessary. However, for urban areas with complex storm sewer networks and terrain structures, high-resolution grids and detailed networks can significantly prolong the analysis. Therefore, determining an appropriate level of network simplification and a suitable surface grid resolution is essential to secure the golden time for urban flood forecasting. In this study, InfoWorks ICM, a software program capable of 1D-2D coupled simulation, was used to examine urban flood forecasting performance for storm sewer networks with various levels of simplification and different surface grid resolutions. The inundation depth, inundation area, and simulation time were analyzed for each simplification level. Based on the analysis, the simulation time was reduced by up to 65% upon simplifying the storm sewer networks and by up to 96% depending on the surface grid resolution; further, the inundation area was overestimated as the grid resolution increased. This study provides insights into optimizing the simplification level and surface grid resolution for storm sewer networks to ensure efficient and accurate urban flood forecasting.

• 보건행정학회지
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• 제18권3호
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• pp.1-17
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• 2008

The measurement and management of patient satisfaction has become one of the key issues in the last two decades. Hospitals must thoroughly understand the needs of their customers and design products and health services that meet and exceed their expectations. The importance-performance analysis(IPA) is a widely used analytical technique that yields strategies for managing customer satisfaction in a variety of applications. IP A is a two-dimensional grid based on customer-perceived importance of quality attributes and attribute performance. Depending on the interplay of these two dimensions, four strategies can be derived. The aim of this study is to develop the management strategies for improving patient satisfaction in university hospitals using the I-P analysis. The attributes on inpatient service quality in 4 university hospitals was investigated using the Martilla and James(l977)' s a mean adjusted I-P grid where the axes of the grid cross at the average rating point of all items. The patient satisfaction questionnaires were completed by 600 hospital inpatients. The main statistical methods are path analysis and IPA with SPSS 12.0 and AMOS 4.0 statistical softwares. The two attributes, physician and medical service, administrative staff kindness attributes position in first quadrant(Keep Up the Good domain). The nurse and nursing service attributes position in second quadrant(Possible Overkill domain). The two attributes, convenience of check-in service, facilities and physical environment position in third quadrant(Low Priority domain). Finally the quality of inpatient service(food etc.) attributes position in fourth quadrant(Concentrate Here domain). These findings show various implications on the development of strategies in university hospitals in the future. It was determined that quality of inpatient service(food etc.) need to concentrate more on investments. These investments include a taste, price, proper provision of food service and quick response of pain management. A low priority was given to investment in streamlining the check-in process of inpatient and hospital facilities and physical environment in the long run.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.329-330
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• 2012

The rising popularity of renewable energy sources resulted in development of the units of higher rated powers, where the large-scale plants and grid-connected type solar power systems are increased. Therefore, the importance of grid stabilization, which depends on each country or system-type, has been strengthened by different grid-codes or certifications. In this paper, the control scheme of three-phase photovoltaic system is enhanced, where both injected active and reactive powers are simultaneously controlled with the consideration of the certification of the Germany Association of Energy and Water Industries (BDEW). Experimental results are shown to verify the theoretical analysis.