• 대한전기학회논문지:전력기술부문A
• /
• 제54권11호
• /
• pp.507-517
• /
• 2005

This paper presents the results of critical contingency analysis for the Korean power system which is performed to identify the impact of the critical contingencies on the Korean power system and set up a short term system operation planning for the purpose of preventing large scale blackout. The static and dynamic simulation is carried out for each critical contingency and the simulation results for each contingency are shown under the peak load condition for the year 2005, 2007 and 2010.

• Korean Chemical Engineering Research
• /
• 제46권4호
• /
• pp.739-746
• /
• 2008

반응증류 공정은 전형적인 반응공정과 증류공정을 통합하여 증류탑에서 반응과 동시에 분리를 수행하는 공정이다. 반응증류 공정의 가장 큰 장점은 반응 전환율의 제약과 공비점으로 인한 제약을 효율적으로 극복할 수 있다는 데 있다. 본 연구에서는 에스테르화반응으로 얻어지는 대표적인 물질인 메틸 아세테이트를 합성, 생산하는 연속 반응증류 공정의 상세한 수학적 모델을 구성하여 동적 모사 및 동적 최적화를 수행하였다. 상평형을 가정한 평형단 모델에 반응속도 식을 적용하여 분리와 반응이 함께 일어나는 증류탑과 재비기 및 응축기를 수학적 모델로 구성하여 동적모사를 수행하여 실제 공정이 운전되는 시나리오대로 공정전체를 모사함으로써 공정 개시부터의 공정의 동적 특성을 살펴보았다. 이 동적 모델과 연계되어, 반응증류 공정으로 얻어지는 메틸 아세테이트의 순도를 목적함수로 하는 최적화 문제를 구성하여 그 결과로 최적의 원료주입 분율 및 재비기의 열량 및 환류비 등을 구할 수 있었다. 또한 여기서 얻어진 운전 변수의 값을 변화시킬 때 반응 전환율의 변화를 살펴봄으로써, 최적화 문제의 해로 구해진 운전 변수의 값의 타당성을 증명하였다.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
• /
• pp.315-318
• /
• 2006

This paper concerns about coupled dynamic analysis of the deep-seabed mining system in launching operation. The dynamic behavior of mining system consisting of lifting pipe, buffer station, flexible conduit and self-propelled miner is simulated in time domain. The launching operation is divided into four critical phases: (1) deployment of miner and flexible conduit, (2) deployment of lifting pipe, flexible conduit and miner, (3) touch-down of miner, (4) final launching. The dynamic responses of sub-systems - miner, flexible conduit, buffer and lifting pipe - are analyzed in each launching phase. According to the changing periods of forced excitation at the top, the dynamic responses of sub-systems are diverse in their characteristics. It has been shown that the total integrated responses of sub-systems are strongly affected by the design parameters. Especially, the principal dimensions of flexible conduit seem to be significant in determining of the global response. Based on the simulation results, safe operation conditions are investigated.

• 대한족부족관절학회지
• /
• 제8권1호
• /
• pp.111-113
• /
• 2004

In neurogenic equinovarus deformity, surgical intervention such as tendon transfer or osteotomy can be expected to improve symptoms. However, in rare cases of hereditary spastic paraplegia, the deformity and paralysis gradually progress. So limited operation and early post-operative rehabilitation are preferred to aggressive operation. We would like to report our clinical experience with one case of hereditary spastic paraplegia patient with reference review. A 40 year-old male, given tendon transfer of ankle and foot and tendo achilles lengthening 10 years ago, complained about aggravated spastic paraplegia which resulted in dynamic equinovarus and limited walking ability since his operation. Family history showed limited walking ability of his father with gradually progressing spastic paralysis and he was diagnosed as hereditary spastic paraplegia type I. We had performed a limited operation such as tendo achilles and tibialis posterior lengthening to induce plantigrade standing and walking with crutch. As a result, the patient was able to maintain a stabilized standing posture and walk after the operation. Hereditary spastic paraplegia presents with a progressive paralysis which limits rehabilitation after tendon transfer, and the symptoms can be aggravated. Therefore, considering potential hereditary neurogenic disorders in paients with equinovarus deformity and performing limited operative procedures seem to be important.

• 전기전자학회논문지
• /
• 제23권3호
• /
• pp.1027-1032
• /
• 2019

본 논문에서는 PV-ESS 연계형 시스템의 운용방법에 대한 알고리즘의 개발로 수용가의 경제성 측면에서 PV-ESS 시스템 운용 시 발생할 수 있는 모든 경제적 변수의 변화에 대처할 수 있는 강인한 알고리즘을 구현하였다. 이를 토대로 수용가의 전기요금을 최소화 할 수 있는 PV-ESS의 최적 운용 스케줄을 결정하였다. 즉, PV-ESS 시스템의 운용에 영향을 주는 외생 변수가 바뀌어도 항상 안정적으로 최적의 PV-ESS 운용 스케줄을 결정할 수 있으며 이를 위하여 케이스 생성 기반 3차원 동적 계획법을 개발하였다.

• 산업경영시스템학회지
• /
• 제31권2호
• /
• pp.19-27
• /
• 2008

This paper addresses determining the location of the distribution centers in a discrete dynamic distribution system. In discrete and finite time horizon, the demands of retailers are dynamic for the periods. Some locations among the retailers can be chosen for the role of the distribution centers at the beginning of each period. The distribution centers have to be located at the location of minimizing logistics cost. Logistics cost factors are the operation cost and the fixed cost of distribution center, and the transportation cost. The distribution centers of minimizing sum of operation cost, fixed cost and transportation cost are determined among retailers in each period for the planning period. A mathematical model was formulated and a dynamic programming based algorithm was developed. A numerical example was shown to explain our problem.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.86-92
• /
• 2008

AGT system is a kind of light railway train. AGT system use of concrete track and rubber tire, so it can be reduce the noise and vibration, compare to the normal train system. And, the dynamic responses of normal bridge are influenced by the dynamic characteristics of bridge, the speed of vehicle and the surface roughness of railway. But the AGT system bridge is influenced not only the above facts but also the guiderail unevenness, because, AGT vehicle steered by guiderail. So, in this study, optimized service condition is suggested for the design and operation of AGT system, by the means of experimental study. The experiments are executed for PSC bridge with length of 30m, at the AGT test line in Kyongsan. The test results are compared and investigated according to the prominence. In the test result, the guiderail prominence influenced on the dynamic response of bridge. It shows a increase as compared with no guiderail prominence in the dynamic response value acceleration, displacement, stain.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 2003년도 춘계학술대회논문집
• /
• pp.115-119
• /
• 2003

It requires a great deal of efforts to maintain a distributed system. What is important here is that we should be able to upgrade/maintain a distributed system without stopping the system in operation. For this, what we need is a dynamic reconfigurable framework for highly available distributed systems. In this paper, we propose objects-hot-swapping methods as a solution to our problem. These methods permit us to dynamically upgrade/expand a system without stopping the system in operation. In addition, we analyze these methods and show that an approach based on proxy is the most efficient. Furthermore, we propose two proxy-based approaches: the first one based on the static proxy provides for a fast execution time but it is difficult to implement. The second one based on the dynamic proxy provides for a slow execution time but it is easier to implement. Finally, we propose a hot swapping framework for these static and dynamic proxy.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.942-945
• /
• 2001

This paper presents parallel operation of ZVT(Zero Voltage Transition) Full Bridge Converter with Dynamic Current Shared Inductor. In the conventional method, CT(Current Transformer) have been used to share the load current equally with converters. In this system, at parallel operation of ZVT Full Bridge Converter, dynamic current shared inductor divides the same current of unit converter and ZVT circuit aids to high efficiency. This method which is proposed to compare in the conventional method will do simple control circuit. To show the superiority of this converter is verified through the experiment with a 2kW, 50kHz prototype converter.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집B
• /
• pp.656-661
• /
• 2000

In the recent trend of electric power supply market, a variable pressure operation supercritical once-through steam generator is highlighted as a thermal power plant for cycling load because of its superiority in load regulation. Almost all thermal power plants of the future are expected to be variable pressure operation supercritical once-through units. APESS(Advanced Plant Engineering & Simulation System) is a dynamic simulation software for power plant which is under being developed by Korea Heavy Industries & Construction Co., Ltd. This paper present the introduction of APESS and the result of simulation for variable pressure operation supercritical once-through steam generator.