• 제목/요약/키워드: Problem conduct

검색결과 515건 처리시간 0.021초

여의도공원의 경제적 가치평가: 二段階 二選 假想價値推定法을 적용하여 (Economic Valuation of Yeido Park: Application of Double-Bounded Dichotomous Choice Contingent Valuation Method)

    • 한국조경학회지
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    • 제26권3호
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    • pp.90-103
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    • 1998
  • The purposes of this study are to estimate the economic value and reasonable entrance fee of the Yeido Park, which is under construction in Seoul, by conduct the face-to-face interview. A total of 645 daults were selected by two stage cluster sampling. The senario was designed to meet the requirements for doubgle-bounded dichotomous choice CVM, and distributed with the photograph to epict and compare the current and suggested conditions. A donation vehicle and entrance fee were utilized to find the possibility of strategic behaviors and protest zero, and to make the data estimatable tfor interval censored survival analysis. Date was calibrated by the survival analysis to eleminate the 'fat-tail problem'. Weibull distribution was assumed as a baseline distrubution. The mean WTP of donation and entrance fee was ₩5,281 and ₩783, respectively. The economic value of this park was determined by aggregating the mean value, giving a total WTP for the population of ₩36,861,645,000. This economic value was composed with the use value and existence value. The calibrationi of the Weibull proportional hazard model showed that nearness to the park, age, intention to isit the park, and educational attainment were significant independent variable to influence an amount of donation.

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A Survey on Improvements of Range Hood in Apartment

  • Kang, Kyungmo;Kim, Taeyeon;Lee, Yun-gyu
    • KIEAE Journal
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    • 제17권5호
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    • pp.43-50
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    • 2017
  • Purpose: Residential cooking(gas or electricity) emits many air pollutants. For Removal of these contaminants, range hood is play an important role in the cooking activities. However, deterioration about performance of range hood can be occur in used range hood which is not verified on performance by testing balancing and adjusting in apartment. So, purpose of this study is to improve the range hood against cooking-generated contaminations. Method: To improve hood, survey of range hood which mounted in apartment have to conduct at first. In this study, the survey was conducted for 3 steps. First, Visual inspection for conditions of range hood. Second, questionnaire of operating and maintenance method. Third, interview with user about need for improvement, complainant. Finally, we integrated the survey for range hood and introduced the probable cause of deterioration through this comprehensive survey. Result: Result of measurement for air volume for range hood, A measured air volume has reduced by 41.4, 38.0, 32.0% each step from rated air volume. There are lots of reasons of this phenomenon including to maintenance, air path of duct, lower-cost devices, exhaust ports. For solve this problem, guideline about operating hood, user in apartment will have to supply with maintenance information at first.

아연도금 강판의 $CO_2$ 레이저 용접에서 겹치기 용접의 FEM 시뮬레이션 (FEM Simulation of Lap Joint in $CO_2$ Laser Welding of Zn-coated Steel)

  • 김재도;조치용
    • Journal of Welding and Joining
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    • 제16권1호
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    • pp.52-62
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    • 1998
  • Laser beam welding of zinc-coated steel, especially lap joints, has a problem of zinc vapor produced during welding which has a low vaporization temperature of 906.deg. C. It is lower than the melting temperature of steel (1500.deg. C). The high pressure formed by vaporization of zinc during laser welding splatters the molten pool and creates porosities in weld. During laser lap welds of zinc-coated steel sheets with CW CO$_{2}$ laser the gap size has been analyzed and simulated using a FEM. The simulation has been carried out in the range of gap aetween 0 and 0.16 mm. The vaporized zinc gas has effected to prevent heat from conducting toward the bottom of sheets. In vaporized zinc gas has effected to prevent heat from conducting toward the bottom of sheets. In the case of too small gap size, zinc gas has not ejected and existed between two sheets. Therefore heat was difficult to conduct from the upper sheet to lower sheet and the upper sheet could over-melted. In the case of large gap size the zinc gas has been prefectly ejected but only a part of lower sheet has melted. The optimum range of gap size in the lap welds of zinc-coated steel sheets has been calculated to be between 0.08 and 0.12 mm. According to the comparison of experiment, the simulation is proved to be acceptable and applicable to laser lap welds.

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Practical Text Mining for Trend Analysis: Ontology to visualization in Aerospace Technology

  • Kim, Yoosin;Ju, Yeonjin;Hong, SeongGwan;Jeong, Seung Ryul
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권8호
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    • pp.4133-4145
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    • 2017
  • Advances in science and technology are driving us to the better life but also forcing us to make more investment at the same time. Therefore, the government has provided the investment to carry on the promising futuristic technology successfully. Indeed, a lot of resources from the government have supported into the science and technology R&D projects for several decades. However, the performance of the public investments remains unclear in many ways, so thus it is required that planning and evaluation about the new investment should be on data driven decision with fact based evidence. In this regard, the government wanted to know the trend and issue of the science and technology with evidences, and has accumulated an amount of database about the science and technology such as research papers, patents, project reports, and R&D information. Nowadays, the database is supporting to various activities such as planning policy, budget allocation, and investment evaluation for the science and technology but the information quality is not reached to the expectation because of limitations of text mining to drill out the information from the unstructured data like the reports and papers. To solve the problem, this study proposes a practical text mining methodology for the science and technology trend analysis, in case of aerospace technology, and conduct text mining methods such as ontology development, topic analysis, network analysis and their visualization.

RI-Biomics 분야 인력양성 모델 정립 (Establishment of Model for the Human Resource Development in RI-Biomics Field)

  • 염유선;신우호;황영묵;박태진;박상현
    • 방사선산업학회지
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    • 제7권2_3호
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    • pp.209-219
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    • 2013
  • RI-Biomics field comes into the limelight as a new fusion radiation technology. These rapid development of RI-Biomics cause the necessity of establishment of a new methodical education program model for consistent training of professional manpower in RI-ADME, Biomics field. But domestic current status is not satisfied to training human resource development in RI-Biomics. Actually domestic educational organization related to RI-Biomics just run educational programs oriented basic theory, so practical and fusion education are not existed nowadays for preliminary RI-Biomics expert. Therefore we established a new education program model for educate of the expert in RI-Biomics field to overcome current problem about the route of knowledge that has more monotonous and concentrated tendency and non-professional education. To improve universality and practicality, we conduct education-training model survey about domestic and foreign country. This new human resource development model will contribute to fostering new expert in RI-Biomics field.

공공도서관 장서의 포화에 관한 사례 연구 (Case Study on Collection Saturation of Public Library)

  • 김홍렬
    • 한국도서관정보학회지
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    • 제50권3호
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    • pp.49-69
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    • 2019
  • 본 연구는 공공도서관의 자료이용공간 내 장서포화 상태를 측정하고, 이를 해결할 수 있는 방안을 제안하는데 그 목적이 있다. 연구의 수행을 위하여 특정 지방자치단체 한 곳을 선정하여 이 지방자치단체가 운영하는 공공도서관의 도서관별 장서포화상태를 측정하여 장서포화의 상태와 원인을 밝히고자 하였다. 본 연구를 통해 도출한 연구 결과를 토대로 우리나라 공공도서관에서 장서포화도를 측정하여 장서포화에 대한 심각성을 인지하고, 장서포화의 원인을 파악하여 이를 해결해야 한다는 당면과제를 제시하는데 있다.

Abnormal state diagnosis model tolerant to noise in plant data

  • Shin, Ji Hyeon;Kim, Jae Min;Lee, Seung Jun
    • Nuclear Engineering and Technology
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    • 제53권4호
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    • pp.1181-1188
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    • 2021
  • When abnormal events occur in a nuclear power plant, operators must conduct appropriate abnormal operating procedures. It is burdensome though for operators to choose the appropriate procedure considering the numerous main plant parameters and hundreds of alarms that should be judged in a short time. Recently, various research has applied deep-learning algorithms to support this problem by classifying each abnormal condition with high accuracy. Most of these models are trained with simulator data because of a lack of plant data for abnormal states, and as such, developed models may not have tolerance for plant data in actual situations. In this study, two approaches are investigated for a deep-learning model trained with simulator data to overcome the performance degradation caused by noise in actual plant data. First, a preprocessing method using several filters was employed to smooth the test data noise, and second, a data augmentation method was applied to increase the acceptability of the untrained data. Results of this study confirm that the combination of these two approaches can enable high model performance even in the presence of noisy data as in real plants.

DDPG 알고리즘을 이용한 양팔 매니퓰레이터의 협동작업 경로상의 특이점 회피 경로 계획 (Singularity Avoidance Path Planning on Cooperative Task of Dual Manipulator Using DDPG Algorithm)

  • 이종학;김경수;김윤재;이장명
    • 로봇학회논문지
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    • 제16권2호
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    • pp.137-146
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    • 2021
  • When controlling manipulator, degree of freedom is lost in singularity so specific joint velocity does not propagate to the end effector. In addition, control problem occurs because jacobian inverse matrix can not be calculated. To avoid singularity, we apply Deep Deterministic Policy Gradient(DDPG), algorithm of reinforcement learning that rewards behavior according to actions then determines high-reward actions in simulation. DDPG uses off-policy that uses 𝝐-greedy policy for selecting action of current time step and greed policy for the next step. In the simulation, learning is given by negative reward when moving near singulairty, and positive reward when moving away from the singularity and moving to target point. The reward equation consists of distance to target point and singularity, manipulability, and arrival flag. Dual arm manipulators hold long rod at the same time and conduct experiments to avoid singularity by simulated path. In the learning process, if object to be avoided is set as a space rather than point, it is expected that avoidance of obstacles will be possible in future research.

블록체인 소프트웨어의 취약점을 이용한 OS 커맨드 인젝션 공격에 대한 연구 (Analysis of Blockchain Software Vulnerability against OS Command Injection Attack)

  • 김병국;허준범
    • 정보보호학회논문지
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    • 제29권2호
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    • pp.309-320
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    • 2019
  • 블록체인 기술은 비트코인과 함께 알려졌으며, 급진적인 암호화폐의 성장과 함께 주요 기술로 인식되었다. 블록체인을 활용하기 위한 노력은 다양한 분야에서 이어지고 있으며 지속해서 발전하고 있다. 하지만 블록체인의 발전과 함께 블록체인을 위협하는 보안사고도 증가하고 있다. 이러한 문제를 해결하기 위해 블록체인의 다양한 보안 위협 중 블록체인 소프트웨어의 구현상 문제점을 분석하겠다. 본 논문에서는 블록체인 소프트웨어 중 오픈소스로 개발되는 암호화폐를 보안 관점에서 바라보며 소스코드에 존재하는 취약점을 분석하고, 취약점을 이용한 OS 커맨드 인젝션 공격에 대해 알아보겠다.

Clustering for Home Healthcare Service Satisfaction using Parameter Selection

  • Lee, Jae Hong;Kim, Hyo Sun;Jung, Yong Gyu;Cha, Byung Heon
    • International Journal of Advanced Culture Technology
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    • 제7권2호
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    • pp.238-243
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    • 2019
  • Recently, the importance of big data continues to be emphasized, and it is applied in various fields based on data mining techniques, which has a great influence on the health care industry. There are many healthcare industries, but only home health care is considered here. However, applying this to real problems does not always give perfect results, which is a problem. Therefore, data mining techniques are used to solve these problems, and the algorithms that affect performance are evaluated. This paper focuses on the effects of healthcare services on patient satisfaction and satisfaction. In order to use the CVParameterSelectin algorithm and the SMOreg algorithm of the classify method of data mining, it was evaluated based on the experiment and the verification of the results. In this paper, we analyzed the services of home health care institutions and the patient satisfaction analysis based on the name, address, service provided by the institution, mood of the patients, etc. In particular, we evaluated the results based on the results of cross validation using these two algorithms. However, the existence of variables that affect the outcome does not give a perfect result. We used the cluster analysis method of weka system to conduct the research of this paper.