• Title/Summary/Keyword: power system analysis

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The linear model analysis and Fuzzy controller design of the ship using the Nomoto model (Nomoto모델을 이용한 선박의 선형 모델 분석 및 퍼지제어기 설계)

  • Lim, Dae-Yeong;Kim, Young-Chul;Chong, Kil-To
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.2
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    • pp.821-828
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    • 2011
  • This paper developed the algorithm for improving the performance the auto pilot in the autonomous vehicle system consisting of the Track keeping control, the Automatic steering, and the Automatic mooring control. The automatic steering is the control device that could save the voyage distance and cost of fuel by reducing the unnecessary burden of driving due to the continuous artificial navigation, and avoiding the route deviation. During the step of the ship autonomic navigation control, since the wind power or the tidal force could make the ship deviate from the fixed course, the automatic steering calculates the difference between actual sailing line and the set course to keep the ship sailing in the vicinity of intended course. first, we could get the transfer function for the modeling of ship according to the Nomoto model. Considering the maneuverability, we propose it as linear model with only 4 degree of freedoms to present the heading angle response to the input of rudder angle. In this paper, the model of ship is derived from the simplified Nomoto model. Since the proposed model considers the maximum angle and rudder rate of the ship auto pilot and also designs the Fuzzy controller based on existing PID controller, the performance of the steering machine is well improved.

Research on the Development of Ocean Resort Complex in all Seasons at the East Coast of GyeongBuk Province (경북 동해안지역 전천후 해양리조트단지 조성방안 연구)

  • Lee, Joong-Woo;Lee, Myoung-Kwon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2009.06a
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    • pp.205-209
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    • 2009
  • Recently, the increase of the size of GNP and the expansion of the foreign tour opportunities by the common 5 days work system in a week, reaction of the burden for visiting foreign countries, and expansion of airlines caused the rapid increase of overseas tour but slow increase in the number of foreign tourists, due to the price rise which might impact on the competitive power, and lack of tour infrastructure and attractiveness. As the wide area along the east coast of GyeongBuk Province has great amount of cultural, ocean and natural resources, it helps to get focused the tour industries and maximize the synergy effect through the mutual development coupling the resources and regions. On the basis of the potentials for the growth of east coast area to the international level and the development of local resources, a ocean tour and resort complex for four seasons, which has s strong connection to the local areas resulting the wide tour bond, could help to improve the local economy and balance the development of local province, and furthermore, jump to the level of the center in the East Coast area in the international society. Through the investigation and analysis of the ocean space development status and usage at the advanced foreign countries, the new meaning of the ocean space at the tour and resort complex would be proposed to the relevant local government in fit.

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XML Schema Evolution Approach Assuring the Automatic Propagation to XML Documents (XML 문서에 자동 전파하는 XML 스키마 변경 접근법)

  • Ra, Young-Gook
    • The KIPS Transactions:PartD
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    • v.13D no.5 s.108
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    • pp.641-650
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    • 2006
  • XML has the characteristics of self-describing and uses DTD or XML schema in order to constraint its structure. Even though the XML schema is only at the stage of recommendation yet, it will be prevalently used because DTD is not itself XML and has the limitation on the expression power. The structure defined by the XML schema as well as the data of the XML documents can vary due to complex reasons. Those reasons are errors in the XML schema design, new requirements due to new applications, etc. Thus, we propose XML schema evolution operators that are extracted from the analysis of the XML schema updates. These schema evolution operators enable the XML schema updates that would have been impossible without supporting tools if there are a large number of XML documents complying the U schema. In addition, these operators includes the function of automatically finding the update place in the XML documents which are registered to the XSE system, and maintaining the XML documents valid to the XML schema rather than merely well-formed. This paper is the first attempt to update XML schemas of the XML documents and provides the comprehensive set of schema updating operations. Our work is necessary for the XML application development and maintenance in that it helps to update the structure of the XML documents as well as the data in the easy and precise manner.

A Centralized Deployment Protocol with Sufficient Coverage and Connectivity Guarantee for WSNs (무선 센서 네트워크에서 유효 커버리지 및 접속성 보장을 위한 중앙 집중형 배치 프로토콜)

  • Kim, Hyun-Tae;Zhang, Gui-Ping;Kim, Hyoung-Jin;Joo, Young-Hoon;Ra, In-Ho
    • Journal of the Korean Institute of Intelligent Systems
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    • v.16 no.6
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    • pp.683-690
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    • 2006
  • Reducing power consumption to extend network lifetime is one of the most important challenges in designing wireless sensor networks. One promising approach to conserving system energy is to keep only a minimal number of sensors active and put others into low-powered sleep mode, while the active sensors can maintain a connected covet set for the target area. The problem of computing such minimum working sensor set is NP-hard. In this paper, a centralized Voronoi tessellation (CVT) based approximate algorithm is proposed to construct the near optimal cover set. When sensor's communication radius is at least twice of its sensing radius, the covet set is connected at the same time; In case of sensor's communication radius is smaller than twice of its sensing radius, a connection scheme is proposed to calculate the assistant nodes needed for constructing the connectivity of the cover set. Finally, the performance of the proposed algorithm is evaluated through theoretical analysis and extensive numerical experiments. Experimental results show that the proposed algorithm outperforms the greedy algorithm in terms of the runtime and the size of the constructed connected cover set.

Study on the Plan for Reduction of Credit Risk of Medium-size Construction Companies Preparing for Restructuring (구조조정에 대비한 중견건설사 신용리스크 저감방안에 관한 연구)

  • Lee, YunHong
    • Korean Journal of Construction Engineering and Management
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    • v.21 no.5
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    • pp.64-73
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    • 2020
  • The government announced a plan for fund support to the enterprises with high possibility of recovery and early restructuring for the enterprises with low recovery by objectifying credit assessment system. Such announcement of government could be extended to restructuring risk of middle standing enterprises with low financial soundness by establishing the basis to prepare prompt restructuring by reinforcing the basis for restructuring through capital market. This research analyzed financial soundness based on the financial evaluation of bank by selecting 10 middle standing construction companies which focused on housing business in 2019, based on such analysis result, it was confirmed that there was a high possibility of restructuring risk. This research determined that there would be a decrease in growth rate of construction industry on the whole in 2020 due to fall of economic growth rate and reinforced real estate regulation, accordingly, there's a big possibility for middle standing construction companies with paid-in capital ratio due to its low possibility of maintenance of stable credit rating. This research established KCSI assessment model by utilizing the material of a reliable research institute in order for middle standing construction companies to evade restructuring risk, and indicated risk ratio differentiated per each item through a working-level expert survey. Such research result could suggest credit risk reduction method to middle standing construction company management staffs, and prepare a basis to evade restructuring risk.

A Study of Children's Statements in sexual violence cases of children less than the age of 13 -Focusing on video-recorded hearsay evidence- (13세미만 아동성폭력 재판에서의 아동진술연구 -영상매체를 통한 전문 증거를 중심으로-)

  • Park, Yeon Ju;Kim, Jung Woo
    • Journal of the Korean Society of Child Welfare
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    • no.55
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    • pp.87-111
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    • 2016
  • This study aimed to examine how video-recorded hearsay statements are taken in trial with regard to testimony of children less than the age of 13 in terms of children's rights, and to assess policy implications for the purpose of improving the current system. This study analyzed the precedents in accordance with their facts and contents. The analysis of the contents dealt with the main issues of trials concerning the sexual violence of children less than the age of 13. Specifically, This study selected precedents dealing with video-recorded hearsay statements, which are children's indirect statement, as core legal issues; examined the credibility(probative power) and admissibility of video-recorded statements; and prepared systemic alternatives in accordance with the United Nations Convention on the Rights of the Child, the international standards for the protection of children's rights. As a result, this study proposed creating and utilizing indicators to assess evidence admissibility and the credibility of video-recoded statements in trial, thus reducing judgement through judges' discretion. Also proposed are new regulations with regard to cross-examination coverage of the hearsay statement of a child in a sexual violence trial of concerning children less than the age of 13. This study suggests an improvement in legal policies, based given that children's rights are more vulnerable than those of adults in trial. Nevertheless, this study is limited in that it selected and reviewed only among precedents that are in the public record.

The Effects of SBAR Report Education on Communication Clarity, Communication Satisfaction, Reporting Confidence and Communication competency in Clinical Practice of Nursing Students (간호대학생의 임상실습 동안 적용한 SBAR 보고교육이 의사소통명 확성, 의사소통만족도, 보고자신감과 의사소통능력에 미치는 효과)

  • Jaung, Ae-Hwa;kim, Ji-young;Moon, Mi-Young
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.4
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    • pp.1129-1142
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    • 2021
  • This study was conducted to identify the impact factors of SBAR reporting education applied during clinical practice of nursing students on communication clarity, communication satisfaction, reporting confidence, and communication competency. Data collection period was from December 1st, 2019 to December 20th, 2019 and two nursing universities extracted conveniently for third graders who completed clinical practice for more than six weeks. The number of eligible applicants is 103 who received SBAR reporting and training and 113 who did not receive training. Data were analyzed by t-tests, one-way ANOVA, Pearson's correlation coefficient analysis using the SPSS 21.0 program. Positive correlation were between communication clarity and communication competency(r=.52, p<.001), and between reporting confidence and communication satisfaction(r=.53, p<.001), communication competency and reporting confidence(r=.46, p<.001). communication competency was a significant influence factor with communication clarity(𝛽=.28, p<.001), communication satisfaction(𝛽=.43, p<.001), and reporting confidence(𝛽=.15, p=.009) 49.0% explanatory power. In conclusion, it is necessary for nursing students to develop educational systems and teaching methods to strengthen the reporting system by identifying practical skills during clinical practice.

A Study on the Uniform Mixing of Ammonia-Air with the Change of Ammonia Supply Device Shape in a De-NOx System (탈질설비에서 암모니아 혼합기의 형상에 따른 암모니아-공기 균일 혼합에 관한 연구)

  • Ha, Ji Soo
    • Journal of the Korean Institute of Gas
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    • v.23 no.3
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    • pp.20-26
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    • 2019
  • Selective catalytic reduction(SCR) method is widely used among various methods for reducing nitrogen oxides in combustion devices of coal power plant. In the present study, the computational fluid dynamic analysis was accomplished to derive the optimal shape of ammonia-dilution air mixing device in a ammonia injection grid. The distribution characteristics of flow and $NH_3$ concentration had been elucidated for the reference shape of ammonia mixing device(Case 1). In the mixing device of Case 1, it could be seen that $NH_3$ distribution was shifted to the wall opposite to the inlet of the ammonia injection pipe. For the improvement of $NH_3$ distribution, the case(Case 2) with closing one upper injection hole and 4 side injection holes, the case(Case 3) with installing horizontal plate at the upper of ammonia injection pipe, the case(Case 4) with installing horizontal plate and horizontal arc plate at he upper of ammonia injection pipe were investigated by analyzing flow and $NH_3$ concentration distributions. From the present study, it was found that the % RMS of $NH_3$ for Case 4 was 4.92%, which was the smallest value among four cases, and the range of $R_{NH3}$ also has the optimally uniform distribution, -10.82~8.34%.

A Study on Environmental Impact Assessment Guidelines for Marine Environmentsin Construction Projects of Offshore Waste Disposal Landfills (해상최종처리장 건설사업의 해양환경 환경영향평가 가이드라인 개발 연구)

  • Lee, Haemi;Son, Minho;Kang, Taesoon;Maeng, Junho
    • Journal of Environmental Impact Assessment
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    • v.28 no.3
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    • pp.312-331
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    • 2019
  • An offshore waste disposal facility refers to a landfill site for final landfilling of stabilized inorganic solid waste such as land and marine waste incineration materials, and the aim of such a facility is to solve the problem of insufficient waste disposal space on land and create and develop environmentally friendly marine spaces. The purpose of this study is to prepare guidelines for the construction of offshore waste disposal facilities, which reflect the need and importance of paying sufficient heed to environmental considerations from the initial stage of the project, in order to investigate, predict, and assess how such guidelines will affect the marine environment in relation to the construction of offshore waste disposal facilities, with the goal of minimizing the impact on and damage to the environment. For the purpose of this research, guidelines focusing on the construction of offshore waste disposal facilities were derived through an analysis of domestic cases and similar foreign cases and an assessment of their level of compliance with existing EIA guidelines through the operation of a discussion forum. In order to review the EIA report on similar cases in Korea, 17 EIA documents (2005~2016) for dredged soil dumping areas and ash ponds of thermal power plants were analyzed to investigate the status of marine organisms, marine physics, marine water quality, and marine sediment and to understand what types of problems can occur and what improvement measures can be taken. The purpose of these guidelines were to minimize damage to the marine environment by promoting EIA protocols in accordance with scientific and systematic procedures, to reduce the consultation period related to projects, to resolve social conflicts, and to reduce economic costs.

A Study on the Policy Innovation Plan for Public Technology Commercialization (공공기술사업화의 정책 혁신 방안에 관한 연구)

  • Yun, Jeong-Keun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.2
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    • pp.212-220
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    • 2021
  • National R&D investment has steadily increased, reaching number 5 in the world as of 2018. However, for public technology commercialization, the level of discovery of policy models through various cooperation initiatives between government ministries is insufficient, and the performance system that can spread technology commercialization is also limited. In this respect, in order to create results in public technology commercialization, it is necessary to prepare alternatives to strengthen multi-ministerial policy cooperation and increase policy execution power. In this paper, we analyzed the current state of national R&D projects by major ministries and suggested an optimized technology commercialization plan through analysis of the structure, budget, and form of each project. In particular, an alternative in terms of policy efficiency was suggested by analyzing the problems of policy discovery that have not been studied previously. This study is of great significance in that it diagnosed problems of public technology commercialization in terms of the lack of systematic research on public technology commercialization and suggested policy advancement for the spread of technology use and the strategic direction in terms of commercialization.