• Nuclear Engineering and Technology
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• 제55권3호
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• pp.839-849
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• 2023

The development of automation technology to reduce human error by minimizing human intervention is accelerating with artificial intelligence and big data processing technology, even in the nuclear field. Among nuclear power plant operation modes, the startup and shutdown operations are still performed manually and thus have the potential for human error. As part of the development of an autonomous operation system for startup operation, this paper proposes an action coordinating strategy to obtain the optimal actions. The lower level of the system consists of operating blocks that are created by analyzing the operation tasks to achieve local goals through soft actor-critic algorithms. However, when multiple agents try to perform conflicting actions, a method is needed to coordinate them, and for this, an action coordination strategy was developed in this work as the upper level of the system. Three quantification methods were compared and evaluated based on the future plant state predicted by plant parameter prediction models using long short-term memory networks. Results confirmed that the optimal action to satisfy the limiting conditions for operation can be selected by coordinating the action sets. It is expected that this methodology can be generalized through future research.

• KDI Journal of Economic Policy
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• 제13권4호
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• pp.141-153
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• 1991

본고(本稿)에서는 재정당국(財政當局)과 통화당국(通貨當局)를 포괄하는 통합정부(統合政府)의 최적재원조달(最適財源調達)의 관점에서 재정정책(財政政策)과 통화정책간(通貨政策間)의 체계적(體系的)인 연관(聯關)의 존재 여부와 그 내용을 재정우위(財政優位)모델의 이론적 결과에 입각하여 실증적(實證的)으로 고찰하였다. 재정우위(財政優位)모델에서는 통화(通貨)에 의한 직접적(直接的) 재원조달(財源調達) 경로(經路)로서의 seigniorage의 확보와, 간접적(間接的) 경로(經路)로서의 인플레적 편의(偏倚)를 모델화하여 정부예산제약하(政府豫算制約下)에서 최적(最適) 인플레이션율(率) 조세부담율(租稅負擔率)의 선택문제를 다루고 있으며, 이 모델에서 밝혀진 재정(財政) 통화정책(通貨政策)의 적정관계(適正關係)는 최적 인플레이션율(率)/조세부담률(租稅負擔率) 비율(比率)과 한계수입비율간(限界收入比率間)의 정(正)의 상관관계(相關關係)와, 인플레이션율(率)과 조세부담률간(租稅負擔率間)의 정(正)의 상관관계(相關關係)로 함축된다. 1970~80년대 한국경제(韓國經濟)의 거시경제정책영역(巨視經濟政策領域)의 성격 규명을 위한 가설검정(假說檢定) 결과는 이 기간의 재정(財政) 통화변수(通貨變數)의 추이가 통화에 의한 직접적 재원조달측면(財源調達側面)을 강조하는 재정우위(財政優位)의 최적화(最適化) 과정(過程)의 이론적(理論的) 결과(結果)와 부합됨을 보여주고 있다. 본(本) 연구결과(硏究結果)는 한국(韓國)의 거시경제정책기조(巨視經濟政策基調) 설명(說明)에 있어 재정우위(財政優位)의 최적화(最適化)모델이 유용할 수 있으며 재정(財政) 통화정책변수(通貨政策變數)들이 기대되는 수준 이상으로 체계적인 연관을 가지고 있음을 보여주고 있다. 또한 재정우위(財政優位)모델의 이론적 결과의 엄밀한 해석을 통하여 통화공급(通貨供給)과 물가(物價)의 설명변수(說明變數)로서의 재정(財政)의 중요성과 그 구체적 내용을 보여주고 있다.

• Management Science and Financial Engineering
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• 제16권3호
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• pp.21-47
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• 2010

Quantity discounts provide a practical foundation for supply chain inventory policies, improving the supplier's profit and reducing the buyer's inventory cost simultaneously. Traditional quantity-discount research, which deals with inventory coordination between a buyer and a supplier, is extended to a stationary stochastic environment. This research shows that the magnitude of the optimal discounts scheduled by the deterministic quantity discount models may not be large enough to cover the buyer's additional inventory stocking risks under uncertain conditions. As a result, the buyer's total inventory cost may often increase rather than decrease. In contrast, the proposed model allows the supplier to identify the discount level, which shares the buyer's amplified risk associated with temporary overstocking and ensures that both buyer and supplier benefit economically. The performance of the proposed model was tested in the continuous review environments via numerical experiments. The experimental results support the proposed method as a feasible alternative in coordinating inventory decisions under stochastic demand.

• 한국자동차공학회논문집
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• 제8권6호
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• pp.122-129
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• 2000

This paper describes a hybrid dynamic system(HDS) modeling method and result for the drivertrain of a parallel hybrid electric vehicle(PHEV) which consists of a gasoline engine, an electric machine, and a continuous variable transmission (CVT) and proposes a drivetrain control system. The control system has an engine controller, a motor controller, a CVT controller and a supervisory controller for the coordination of all system. The controller keep the speed of engine wheel and the output torque within the optimal operation range based on the experimental data. We also developed a MATLAB/SIMULINK program for the performance simulation of PHEV drivetrain model and controllers and compared the simulation result with the experiment result in the recent literatures.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.433-437
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• 2005

The goal of our research is to develop a formal modeling methodology for supervisory and controlling systems that have artificially intelligent features. This approach is agent-based and central to the development of the model of mobility agent considering reactivity for real-time purpose and deliberation for optimal realization and safe-fail problems for critical systems like Intelligent Transportation Systems by high-level Petri net. By using nets within nets we investigate the concurrency of the system and the agent in one model without losing the needed abstraction, and synchronous channels are introduced to denote the coordination and communication. Finally an example is demonstrated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.295-297
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• 2002

In this study, Genetic Algorithm(GA) is applied for voltage and reactive power control in power system. In power system, switched shunt capacitors are used to improve the voltage profile and to reduce power losses. There are many switched shunt capacitors in power system. Therefore, it is necessary to coordinate these switched shunt capacitors. A Genetic Algorithm(GA) is used to find optimal coordination of switched shunt capacitors in power system. The effectiveness of the proposed approach is demonstrated in KEPCO's power system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.178.3-178
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• 2001

This paper is concerned with designing a neural network based navigator that is optimized in a user-defined sense for a mobile robot using ultrasonic sensors to travel to a goal position safely and efficiently without any prior map of the environment. The neural network has a dynamically reconfigurable structure that not only can optimize the weights but also the input sensory connectivity in order to meet any user-defined objective. Therefore, in this research, we can select an optimal subset of sensory inputs that results in the best performance related to both navigation and structural complexity. Further, this research uses the manually trained initial population and the modular neural network to alleviate ...

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.298-299
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• 2008

In this paper, supposed that can measure power quality of bus and can calculate this cost in case electric charges about customer are imposed by each bus. When reflected this in system planning, expected cost proposed following method through sample system. We calculated the nodal cost by OPF(optimal power flow) in system and the drop numbers that happen during year of loads utilizing VSCC. Also calculated BPQC using the disruption numbers. As a result, calculated bus total cost including power quality cost through case study.

• 대한산업공학회지
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• 제3권1호
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• pp.49-53
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• 1977

The coordinated control of the traffic signals of adjacent intersections can reduce delays, relative number of stops and congestions in the coordinated traffic area. The road capacity can be increased to a certain extend because the stopping and starting of vehicles facing red traffic lights can be avoided in many instances due to the progression established along an artery. However, if traffic centers or leaves the main flow in irregular volumes on the intermediate road section, a coordination of traffic signals is unnecessary and may even be harmful. Therefore, a computer simulation model to simulate and predict the effectiveness of a synchronized traffic signal system in the CBD of Seoul was developed and alternative policy variables, such as cycle time, offsets, phase splits, to be fed into the simulation model had to be generated. This is a report of (1) the development of a heuristic algorithm for the determination of phase splits when there are amber periods specifically reserved for left turns and (2) the computerization of time-space diagramming.

• 한국경영과학회지
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• 제37권2호
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• pp.45-56
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• 2012

This paper considers a supply chain consisting of a component manufacturer and a product manufacturer. The component manufacturer provides components for the product manufacturer based on a vendor-managed inventory type of supply contract, and also faces demands from the market with the option of to accept or reject each incoming demand. Using the Markov decision process model, we examine the structure of the optimal production control and inventory rationing policy. Two types of heuristics are presented. One is the fixed-buffer policy and the other uses two linear functions. We implement a computational study and present managerial insights based on the observations.