• Title/Summary/Keyword: Dynamic Schedule

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Development of An Expert system with Knowledge Learning Capability for Service Restoration of Automated Distribution Substation (고도화된 자동화 변전소의 사고복구 지원을 위한 지식학습능력을 가지는 전문가 시스템의 개발)

  • Ko Yun-Seok;Kang Tae-Gue
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.12
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    • pp.637-644
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    • 2004
  • This paper proposes an expert system with the knowledge learning capability which can enhance the safety and effectiveness of substation operation in the automated substation as well as existing substation by inferring multiple events such as main transformer fault, busbar fault and main transformer work schedule under multiple inference mode and multiple objective mode and by considering totally the switch status and the main transformer operating constraints. Especially inference mode includes the local minimum tree search method and pattern recognition method to enhance the performance of real-time bus reconfiguration strategy. The inference engine of the expert system consists of intuitive inferencing part and logical inferencing part. The intuitive inferencing part offers the control strategy corresponding to the event which is most similar to the real event by searching based on a minimum distance classification method of pattern recognition methods. On the other hand, logical inferencing part makes real-time control strategy using real-time mode(best-first search method) when the intuitive inferencing is failed. Also, it builds up a knowledge base or appends a new knowledge to the knowledge base using pattern learning function. The expert system has main transformer fault, main transformer maintenance work and bus fault processing function. It is implemented as computer language, Visual C++ which has a dynamic programming function for implementing of inference engine and a MFC function for implementing of MMI. Finally, it's accuracy and effectiveness is proved by several event simulation works for a typical substation.

Cases Study of Accidents in High Risk Organizations by System Dynamics (시스템 다이내믹스 기법을 활용한 고위험 조직 사고 사례 분석)

  • Oh, Youngmin;Ryu, Jin
    • Korean System Dynamics Review
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    • v.16 no.3
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    • pp.5-29
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    • 2015
  • The importance of the concept of safety culture has increased in the security of high-risk facility after Chernobyl accident in 1986. This paper elaborated the concept of safety culture and its main factors by Causal Loop Diagram. Due to the decline of safety culture, the occurrence of incidents and accidents require more and more corrective actions to the members of high-risk facilities and thereby increasing their workloads. Employees who must complete the task within the given time have to have time pressures and don't comply with the rules and procedures. Also, a schedule pressure is a big stress for employees, causing mistakes in precision work. In order to improve these problems, CLD of the safety culture in this paper suggests hiring more workers, re-allocation of given workloads and strengthen the learning, communication capabilities and safety leadership. In addition, the two real accident cases were analyzed to test the feasibility of the System Dynamic simulation model through the process of structuring the fault trees on the stationary black out accident in Kori unit 1 in South Korea and Kleen Energy power station explosion in US. The simulation results show that the various safety factors cause the serious accident combined with mechanical failure and safety culture will reduce the possibility of the accidents in these high-risk organizations. This simulation model can contribute to analyzing the impact of the organizational and human factors of safety culture and can provide the alternatives in high-risk facilities.

A Power-Aware Scheduling Algorithm by Setting Smoothing Frequencies (주파수 평활화 기법을 이용한 전력 관리 알고리즘)

  • Kweon, Hyek-Seong;Ahn, Byoung-Chul
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.45 no.1
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    • pp.78-85
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    • 2008
  • Most researches for power management have focused on increasing the utilization of system performance by scaling operating frequency or operating voltage. If operating frequency is changed frequently, it reduces the real system performance. To reduce power consumption, alternative approaches use the limited number of operating frequencies or set the smoothing frequencies during execution to increase the system performance, but they are not suitable for real time applications. To reduce power consumption and increase system performance for real time applications, this paper proposes a new power-aware schedule method by allocating operating frequencies and by setting smoothing frequencies. The algorithm predicts so that frequencies with continuous interval are mapped into discrete operating frequencies. The frequency smoothing reduces overheads of systems caused by changing operating frequencies frequently as well as power consumption caused by the frequency mismatch at a wide frequency interval. The simulation results show that the proposed algorithm reduces the power consumption up to 40% at maximum and 15% on average compared to the CC RT-DVS.

An Efficient Channel Selection and Power Allocation Scheme for TVWS based on Interference Analysis in Smart Metering Infrastructure

  • Huynh, Chuyen Khoa;Lee, Won Cheol
    • Journal of Communications and Networks
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    • v.18 no.1
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    • pp.50-64
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    • 2016
  • Nowadays, smart meter (SM) technology is widely effectively used. In addition, power allocation (PA) and channel selection (CS) are considered problems with many proposed approaches. In this paper, we will suggest a specific scenario for an SM configuration system and show how to solve the optimization problem for transmission between SMs and the data concentrator unit (DCU), the center that collects the data from several SMs, via simulation. An efficient CS with PA scheme is proposed in the TV white space system, which uses the TV band spectrum. On the basic of the optimal configuration requirements, SMs can have a transmission schedule and channel selection to obtain the optimal efficiency of using spectrum resources when transmitting data to the DCU. The optimal goals discussed in this paper are the maximum capacity or maximum channel efficiency and the maximum allowable power of the SMs used to satisfy the quality of service without harm to another wireless system. In addition, minimization of the interference to the digital television system and other SMs is also important and needs to be considered when the solving coexistence scenario. Further, we propose a process that performs an interference analysis scheme by using the spectrum engineering advanced Monte Carlo analysis tool (SEAMCAT), which is an integrated software tool based on a Monte-Carlo simulation method. Briefly, the process is as follows: The optimization process implemented by genetic evolution optimization engines, i.e., a genetic algorithm, will calculate the best configuration for the SM system on the basis of the interference limitation for each SM by SEAMCAT in a specific configuration, which reaches the solution with the best defined optimal goal satisfaction.

Real Time Scheduling for Multiple Yard Cranes in an Automated Container Terminal (자동화 컨테이너 터미널의 복수 장치장 크레인을 위한 실시간 작업 계획 수립)

  • Park, Tae-Jin;Choe, Ri;Ryu, Kwang-Ryel
    • Journal of Navigation and Port Research
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    • v.31 no.10
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    • pp.869-877
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    • 2007
  • This paper proposes a realtime scheduling method using local search algorithm for non-crossable yard cranes in automated container terminal. To take into consideration the dynamic property of yard crane operation and satisfy the real time constraint, the proposed method repeatedly builds crane schedule for the jobs in a fixed length look-ahead horizon whenever a new job is requested In addition, the proposed method enables the co-operation between yard cranes through prior re-handling and re-positioning in order to resolve the workload imbalance problem between the two cranes, which is one of the primary causes that lower the performance of yard cranes. Simulation-based experiments have shown that the proposed method outperforms the heuristic based methods, and the cooperation scheme contributes a lot to the performance improvement.

Construction of Database for Application of APEX Model in Korea and Evaluation of Applicability to Highland Field (APEX 모델의 국내 적용을 위한 데이터베이스 구축 및 고랭지 밭에 대한 적용성 평가)

  • Koo, Ja-Young;Kim, Jonggun;Choi, Soon-Kun;Kim, Min-Kyeong;Jeong, Jaehak;Lim, Kyoung Jae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.59 no.6
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    • pp.89-100
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    • 2017
  • The Agricultural Policy/Environmental eXtender (APEX) model was developed to extend EPIC's capabilities of simulating land management impacts for small-medium watershed and heterogeneous farms. APEX is a flexible and dynamic tool that is capable of simulating a wide array of management practices, cropping systems, and other land uses across a broad range of agricultural landscapes. APEX have its own agricultural environmental database including operation schedule, soil property, and weather data etc., by crops. However, agriculture environmental informations the APEX model has is all based on U.S. As this can cause malfunction or improper simulation while simulating highland field. In this study, database for APEX model to be utilized for South Korea established with 44,814 agriculture fields in Pyeongchang-gun, Korea from 2007 to 2016. And assessed domestic applicability by comparing T-P unit load criteria presented by National Institution of Environmental Research and result of APEX model. As a result of APEX model simulation, average T-P value for decade was 6.18. Average T-P of every year except 2011 was in range of 5.37~10.43 and this is being involved into criteria presented by National Institution of Environmental Research. It is analyzed that adjusting slope factor can make the model applicable for domestic agricultural environment.

Study for Operation Method of Underwater Cable and Pipeline Burying ROV Trencher using Barge and Its Application in Real Construction

  • Kim, Min-Gyu;Kang, Hyungjoo;Lee, Mun-Jik;Cho, Gun Rae;Li, Ji-Hong;Yoon, Tae-Sagm;Ju, Jaeheung;Kwak, Han-Wan
    • Journal of Ocean Engineering and Technology
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    • v.34 no.5
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    • pp.361-370
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    • 2020
  • We developed a heavy-duty work class ROV trencher named URI-T (Underwater robot it's trencher) that can conduct burial and maintenance tasks for underwater cables and small diameter pipelines. It requires various supporting systems, including a dynamic positioning (DP) vessel, launch and recovery system (LARS), A-frame, and winch in order to perform burial tasks because of its dimensions (6.5 m × 5.0 m × 4.5 m, 20 t) and the tough working environment. However, operating a DP vessel has disadvantages as it is expensive to rent and operate and it is difficult to adjust the working schedule for some domestic coast construction cases. In this paper, we propose a method using a barge instead of a DP vessel to avoid the above disadvantages. Although burying the cable and pipeline using a barge has lower working efficiency than a DP vessel, it can save construction expenses and does not require a large crew. The proposed method was applied over two months at the construction of the water supply in Yokji-do, and the results were verified.

Effects of plyometric training on Sargent jump, posture control and lower extremity injury criterion in Taekwondo demonstrator (플라이오메트릭 트레이닝이 태권 시범 선수들의 서전트 점프, 자세 조절 및 하체 부상 준거에 미치는 영향)

  • Park, Woo-Young
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.3
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    • pp.851-859
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    • 2021
  • The purpose of this study was to investigate the effects of six weeks of plyometric training on Sargent jumps, posture control, and lower extremity injury criterion in Taekwondo demonstrator. Twenty healthy collegiate Taekwoondo demontrators were randomly assigned to either an exercise group (Ex = 10), and a control group (Con = 10), Con maintained their normal Taekwoondo demontration training schedule. Whereas Ex group completed the plyometric program in three times a week, 60 minute for 6 weeks. Testing before and after training include the Sargent jump, back muscle strength, Y-balance and lower extremity injury criterion. There are no significant increase in back muscle strength, but significant increase in Sargent jump. In postural control, the anterior was not significant, but there was a significant increase in the left and right posterolateral, posteromedial and the total score showed that there was no risk of injuries. In conclusion, plyometric training is a training method that needs to be actively utilized for power, dynamic posture control, lower extremity injury prevention, and rehabilitation.

Dynamic Developmental Factors and their Problem Solving of Patients that Abuse Marihuana (마리화나 남용환자의 역동적인 발달요인과 문제해결)

  • 원정숙
    • Journal of Korean Academy of Nursing
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    • v.4 no.3
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    • pp.105-116
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    • 1974
  • This study was made on patients who were Hospitalized due to sickness caused by the abuse of marihuana at the Psychiatric Section of a hospital during the period from Feb. to Oct., 1974. The following conclusion was obtained by reviewing the literature with respect to the nursing, and problem solving of those patients. 1. It appears that marihuana is a comparatively mild intoxicant in ordinary preparation without causing physical dependence or tolerance. 2. According to the status of men who are marihuana smokers, approximately 20% of them were college students, those preparing to retake college entrance examinations, non-employed and pharmacists. The men belong mostly to the middle foreigner′s mistress of higher, income bracket, and in the case of women, most of the smokers were US. servicemen entertainers. 3. Dynamic developmental factors: Case 1. : The patient had a characteristic, hysterical and emotionally unitable character, and was of low intelligence, In addition, to this already existing problem, the added uses of marihuana caused a mental illness to develope. Case 2 : The character, was reserved and introspective, her creative power and sentiment was fading and his ability of self-control was weakened. She used the smoking of marihuana to get rid of her own feeling of inferiority complex and tensions coming from interpersonal relationships. Case 3 : The patient was unconditionally resistive to the authoritativeness of superiors and irresponsible in his relationship with women, in his attitude concerning sex in general. He smoked marihuana because he felt become peace-loving and get enchanted experience through smoking it. 4. The points of issue appearing from the above case; (1) Movement of anti-social feelings against the "established system" by the youngsters. (2) Family problem. (3) Shamelessness, loss of motivation, disorderly attitude toward the sex, (4) Worries concerning the future. (5) Lack of knowledge concerning smoking of cigarette and marihuana. Chronic use of marihuana made, those youngman who had originally been ambitions to achieve something in life, lazy, inefficient, unable to make long-term plans, are such weak mined persons that they did not try to overcome problems when encountered. This will pose a great and important question in the mental health of the society, 5. Treatment and Problem sieving According to the literature, we will have to place importance upon hospitalized treatment The phases of treatment were divided into five parts. (1) Prehospital phase (2) Withdrawal Phase (3) Rehabilitation phase (4) Transitional phase (5) After-care phase The experiments have proved that there was much progress in the recovery of patients through environment therapy, supportive therapy and group psychotherapy. This was the above mentioned 5 phases of treating process in accordance with the weekly schedule of the hospital. It was thought that the patients would require prolonged after care management even after they were released from the hospital and that they will also require periodic visit, to the hospital and doctor′s interview with their family. In conclusion, the question of the young generation and marihuana smoking is becoming a great social problem in which their resistances to the "established system" and society is growing in the from of antiestablishment movements. In our country, the smoking of marihuana is gradually developing, therefore, I think, that it would be a very fortunate thing for us, if this report could be helpful for the motivation of further study on the questions of the young generation and its problems.

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A System Simulation Model of Proton Exchange Membrane Fuel Cell for Residential Power Generation for Thermal Management Study (가정용 연료전지 시스템의 열관리 해석을 위한 시스템 운전 모델 개발)

  • Yu, Sang-Seok;Lee, Young-Duk;Ahn, Kook-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.1
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    • pp.19-26
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    • 2010
  • A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be coped with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. The thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, thermal management system of PEMFC stack is modeled to understand the dynamic response during load change. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. The different operating strategy is applied for each cooling circuit considering the duty of those two circuits. Even though the capacity of PEMFC system (1kW) is enough to supply hot domestic water for residence, heat-up of reservior takes some hours. Therefore, in this study, time schedule of the simulation reflects the heat-up process. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.