• The Journal of the Acoustical Society of Korea
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• 제17권4E호
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• pp.28-34
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• 1998

In most switching system, the processing unit is designed to work efficiently even at relatively high loads, but when the offered traffic exceeds a particular level, the rate of completed calls can fall drastically. A single call handled by the switching system consists of a sequence of events or messages that has to be processed by the control unit. The control unit is not only incapable of handling all of the offered calls, but also its call handling capability can drop as the offered load increases. The real time available for call processing is a critical resource that requires careful management. Therefore, the overloading of this resource must be detected by a subscriber in the from of a dial tone delay or an uncompleted call which is either blocked or mishandled. The subscriber may respond by either dialing prematurely or by re-attempting a call. This action can further escalate the processors load, which is spent for uncompleted calls. Unless a proper control is used, the switching system can finally break down. In this paper, we paper, we propose a fuzzy overload detection and control method for switching systems, which can by generating fuzzy rules via fuzzy aggregation networks. Simulation results involving a switching system is given.

• 한국항해항만학회지
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• 제43권3호
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• pp.197-208
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• 2019

공 컨테이너 장치장의 사양, 취급 장비, 운영방법이 공 컨테이너 적하 시 발생할 수 있는 재취급 기대횟수에 미치는 영향을 연구하였다. 다수 선사의 다양한 유형의 공 컨테이너를 서로 분리된 공간에 저장한다면 저장 공간을 충분히 활용할 수 없고, 저장 공간의 활용도를 높이기 위해 여러 선사의 공 컨테이너를 혼적하여 함께 저장한다면 적하작업 중에 추가로 재취급이 발생할 수 있다. 한 베이에서 적하작업을 위하여 공 컨테이너를 인출하는 시점에 기대되는 재취급 횟수를 계산하기 위해 필요한 여러 가지 수식을 유도하였다. 트랜스퍼 크레인과 탑 핸들러를 취급 장비로 간주하여 다양한 인출 전략을 검토하였다. 장치장의 다양한 설계 및 운영 매개 변수가 재취급 횟수에 미치는 효과를 확인할 목적으로 수치실험을 수행하였다.

• 한국축산시설환경학회지
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• 제13권2호
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• pp.81-88
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• 2007

출하전 절식과 출하 취급이 출하돈의 혈액성상과 도체품질에 미치는 영향을 분석하기 위하여 출하전 12시간, 24시간 절식한 그룹 및 절식하지 않는 그룹으로 구분하고 각각의 그룹에 대하여 출하 취급을 최대한 부드럽게 혹은 상차, 하차, 계류 과정에 전기봉 사용을 포함하여 고의적으로 거칠게 하는 그룹으로 나누어 체중 약 110kg에 출하되는 삼원교잡종 비육돈 144두를 공시하여 조사, 분석하였다. 모든 출하돈은 계류장 도착 후 3시간 동안 계류하였다. 혈액은 도축직후에 채취하였고 배최장근 시료는 도축 12시간 후(overnight)에 채취하여 분석에 사용하였다. 혈중 glucose 농도는 절식하지 않은 그룹에 비하여 12시간 및 24시간 절식 그룹이 낮았으나 cortisol 농도는 반대로 절식하지 않은 그룹에 비하여 24시간 절식 그룹이 높게(p<0.05) 나타났다. 스트레스와 관련된 glucose, cortisol, creatine kinase 및 lactate dehydrogenase 농도는 출하 취급을 부드럽게 한 그룹에 비하여 고의적으로 거칠게 취급한 그룹에서 높았다. 그러나 스트레스 관련 혈액성상에 대한 절식시간과 취급 스트레스간의 상호작용 효과는 인정되지 않았다. PSE 발생율과 drip loss는 절식하지 않은 그룹보다 12시간, 24시간 절식 그룹이 낮았으나 도체 pH와 육색은 절식 시간의 영향은 나타나지 않았다. 그러나 PSE 발생율과 도체의 이화학적 특성은 출하 스트레스에 의한 차이가 인정되지 않았다. 결론적으로 출하전 12시간(하루밤) 절식은 PSE 발생을 줄이기 위한 좋은 방법이 될 수 있다. 또한 충분한 계류는 출하시 거친 취급으로 인한 도체품질에 미치는 영향을 줄일 수 있을 것으로 보인다. 그러나 출하 취급이 거칠면 혈중 스트레스 관련 지표들의 농도가 증가하여 동물복지를 나쁘게 할 수 있어 거친 취급은 피해야 할 것으로 판단된다.

• 한국공작기계학회논문집
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• 제14권4호
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• pp.81-88
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• 2005

This paper attempts to derive the dynamic model of handling tasks in finger robot which grasps stable and manipulates a rigid object with some dexterity. Firstly, a set of differential equation describing dynamics of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. Secondly, the roblems of controlling both the forces of pressing object and the rotation angle of the object under the geometric constraints are discussed. The effect of geometric constraints of area-contacts between the link's end-effector and the object is analyzed and the model based on the differential-algebraic equations is presented. In this paper, the control method for dynamic stable grasping and enhancing dexterity in manipulating things is proposed. It is illustrated by computer simulation and the experiment that the control system gives the performance improvement in the dynamic stable grasping and nimble manipulating of the dual fingers robot with soft tips.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3277-3290
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• 2023

Nuclear power plant (NPP) operations with multiple objectives and devices are still performed manually by operators despite the potential for human error. These operations could be automated to reduce the burden on operators; however, classical approaches may not be suitable for these multi-objective tasks. An alternative approach is deep reinforcement learning (DRL), which has been successful in automating various complex tasks and has been applied in automation of certain operations in NPPs. But despite the recent progress, previous studies using DRL for NPP operations have limitations to handle complex multi-objective operations with multiple devices efficiently. This study proposes a novel DRL-based approach that addresses these limitations by employing a continuous action space and straightforward binary rewards supported by the adoption of a soft actor-critic and hindsight experience replay. The feasibility of the proposed approach was evaluated for controlling the pressure and volume of the reactor coolant while heating the coolant during NPP startup. The results show that the proposed approach can train the agent with a proper strategy for effectively achieving multiple objectives through the control of multiple devices. Moreover, hands-on testing results demonstrate that the trained agent is capable of handling untrained objectives, such as cooldown, with substantial success.

• Archives of Reconstructive Microsurgery
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• 제9권2호
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• pp.172-178
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• 2000

With esthetic concern in the reconstruction of skin and soft tissue defects of face, the use of local flap has been the method of choice. However, when there is extensive tissue loss in the face, local flaps do not provide satisfactory results. The amazing development of microsurgical technique has decreased the percentage of free flap failure, thus making free flap use in reconstruction of facial soft tissue defects. Many free flaps has been applied for reconstruction of face defects. Especially, the radial forearm flap has numerous advantages with which facial reconstruction is made possible. But, its disadvantages are ; the sacrifice of one major artery supplying the hand and donor site complications. In order to circumvent these disadvantages, we employed posterior interosseous artery(PIA) forearm free flap for the reconstruction of the face defects. The posterior interosseous forearm island flap was first described by Zancolli and Angrigiani(1985). Currently, the PIA island flap and free flap have been used for hand reconstructions. The disadvantages of the PIA flap are ; the small caliber of the pedicle, different locations of the perforating branches, and the proximity of the motor branch of the radial nerve. But, its advantages lies in preserving the major artery of the hand, minimal donor site morbidity, and fairly well matched skin texture and color, and that the flap volume is sufficient, not too bulky with convenient handling. By using this flap, we performed 1 case of tumor resection and 1 case of traumatic defect. From our experiences we conclude that it is one of many useful methods in the reconstruction of the skin and soft tissue defects of the face. We also have discussed advantages and some limitations of various free flaps for reconstruction of the face.

• 한국정밀공학회지
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• 제20권1호
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• pp.187-195
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• 2003

The performance of shock absorber is directly related to the car behaviour and performance, both for handling and ride comfort. The displacement sensitive shock absorber has two modes of damping force (i.e. soft and hard) according to the position of piston. In this study, a mathematical nonlinear dynamic model is introduced to predict the performance of displacement sensitive shock absorber. Especially in this paper, the transient zone is considered and the simulation result is well fit with experimental data. And the vehicle dynamic characteristic of displacement sensitive shock absorber is presented using quarter car simulation model. The simulation results of frequency response are compared with passive shock absorber.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.91-91
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• 2001

This paper is on 3D virtual reality simulator for terminal in connection with terminal operation system in real terminal in order to reflex complicated terminal operation and environment. This simulator has been developed based on knowledge of terminal planning and operation analysis and advanced software technologies that TSB has accumulated over 10 years. In this study, the simulator generates terminal layout and component of terminal in the same environments as the real terminal in Ohi, Japan and uses real operation system using real planning data in the past in order to describe 3D VR simulation that integrates container handling equipment and real time communication of job ordering. In addition, it is suggested various statistics and analysis report can be used to derive decision supporting factors that optimize design of terminal and improve operation, which will eventually increase terminal productivity.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.108.4-108
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• 2002

This paper aims to derive a mathematical model of the dynamics of handling tasks in robot fingers which stably grasps and manipulates a rigid object with some dexterity. Firstly, a set of differential equation describing dynamics of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. Secondly, problems of controlling both the internal force and the rotation angle of the grasped object under the constraints of tight area-contacts are discussed. The effect of geometric constraints of area-contacts on motion of the overall system is analyzed and a method of computer simulation for differential-algebraic equations of overall...

• Journal of Information Processing Systems
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• 제8권4호
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• pp.713-720
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• 2012

Unlike FEM (Finite Element Method), which provides an accurate deformation of soft objects, FFD (Free Form Deformation) based methods have been widely used for a quick and responsive representation of deformable objects in real-time applications such as computer games, animations, or simulations. The FFD-AABB (Free Form Deformation Axis Aligned Bounding Box) algorithm was also suggested to address the collision handling problems between deformable objects at an interactive rate. This paper proposes an enhanced FFD-AABB algorithm to improve the frame rate of simulation by adding the bounding sphere based collision test between 3D deformable objects. We provide a comparative analysis with previous methods and the result of proposed method shows about an 85% performance improvement.