• Journal of Computational Design and Engineering
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• 제1권4호
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• pp.233-242
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• 2014

A magnetically levitated vehicle (Maglev) system is under commercialization as a new transportation system in Korea. The Maglev is operated by an unmanned automatic control system. Therefore, the plan of train operation should be carefully established and validated in advance. In general, when making a train operation plan, statistically predicted traffic data is used. However, a traffic wave often occurs in real train service, and demand-driven simulation technology is required to review a train operation plan and service quality considering traffic waves. We propose a method and model to simulate Maglev operation considering continuous demand changes. For this purpose, we employed a discrete event model that is suitable for modeling the behavior of railway passenger transportation. We modeled the system hierarchically using discrete event system specification (DEVS) formalism. In addition, through implementation and an experiment using the DEVSim++ simulation environment, we tested the feasibility of the proposed model. Our experimental results also verified that our demand-driven simulation technology can be used for a priori review of train operation plans and strategies.

• 한국유체기계학회 논문집
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• 제9권6호
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• pp.22-28
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• 2006

Operation of a microturbine was simulated on the basis of component characteristic parameters obtained from performance test. Characteristic parameters, such as compressor and turbine efficiencies, recuperator effectiveness as well as turbine inlet temperature, were obtained for a wide operation range. Component characteristics including performance maps and characteristic curves were generated using measured data. Based on the component characteristics, a simulation program was constructed and operation of the microturbine was simulated, and the simulated results were compared with the measured data to verify the program. Also, influence of variation in the power control scheme on the operating characteristic and performance of the engine was simulated. The simulation program can be used for predicting operation of both healthy and degraded engine conditions.

• 한국군사과학기술학회지
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• 제11권1호
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• pp.51-56
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• 2008

The counter-fire operation system performs its mission exchanging information with other related systems such as command & control systems and military information systems. In the process of exchanging information, the counter-fire operation system uses a type of data message which contains exchange data information in the format of KMTF. The requirement of data exchange of count-fire operation will continue to evolve. But the EDX(External Data eXchange) configuration item of the current counter-fire operation system can not effectively cope with the variation of data exchange requirements due to its fixed software structure. In the paper, a solution for improving flexibility of external data exchange in counter-fire operation system is proposed.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권1호
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• pp.31-38
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• 2016

A novel self-reference sense amplifier with parallel reading during writing operation is proposed. Read access time is improved compared to conventional self-reference scheme with fast operation speed by reducing operation steps to 1 for read operation cycle using parallel reading scheme, while large sense margin competitive to conventional destructive scheme is obtained by using self-reference scheme. The simulation was performed using standard $0.18{\mu}m$ CMOS process. The proposed self-reference sense amplifier improved not only the operation speed of less than 20 ns which is comparable to non-destructive sense amplifier, but also sense margin over 150 mV which is larger than conventional sensing schemes. The proposed scheme is expected to be very helpful for engineers for developing MRAM technology.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.481-484
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• 2007

Efficiency of geothermal heat exchanger operation has close relation with temperature variation of the aquifer where the exchanger is installed. In the case of long-term operation, temperature distribution of the aquifer would be similar to that of water circulating in the exchanger, which causes the decrease of heat exchange rate. Therefore, the operation period of the heat exchanger should be controlled so that the temperature distribution of the aquifer is recovered. We developed a model to determine the operation period to acquire the optimal efficiency under the given aquifer condition. With this suggested method, when we use closed-loop heat exchanger, the operation efficiency of the geothermal heat exchanger is expected to be maximized by determining the optimal operation period.

• 상하수도학회지
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• 제19권6호
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• pp.781-790
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• 2005

Granular Activated Carbon(GAC) is widely used in drinking water treatment. Many of the problems occurring in the GAC process are associated with the operation goal and performance. The purpose of this study were to evaluate the design, operation, and performance of granular activated carbon process in D water treatment plant. The optimal operation conditions of GAC process such as backwashing condition, granular activated carbon replacement time were discussed. The design, operation and performance of GAC process is influenced by their raw water characteristics and placement within the treatment process sequence. A critical analysis of plants experience and the information from the literature identifies the effectiveness of GAC process and indicates where modifications in design and operation could lead to improved performance. It would be useful to evaluate and optimize the GAC process in other treatment plant.

• 조명전기설비학회논문지
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• 제28권8호
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• pp.54-61
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• 2014

This paper proposes a boost/flux-weakening controller (BFWC) for wide speed operation range having engine and interior permanent magnet synchronous generator (IPMSG) for special equipment vehicle. The proposed BFWC exploits direct torque/flux control (DTFC) scheme based on space vector modulation method to control the constant DC voltage output within the entire speed operation range of engine. And, to improve the response characteristics of maximum torque per ampere (MTPA) operation and flux-weakening operation, the MTPA and flux-weakening feed-forward controllers are applied. To estimate feasibility and usefulness of the proposed controller, the simulation and experimental results are compared.

• 한국멀티미디어학회논문지
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• 제16권4호
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• pp.444-452
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• 2013

Operation time of a function or procedure is a thing that always needs to be optimized. Parallelizing the operation is the general method to reduce the operation time of the function. One of the most powerful parallelizing methods is using GPU. In image processing field, one of the most commonly used operations is morphology operation. Three types of morphology operations kernel, na$\ddot{i}$ve, global and shared, are presented in this paper. All kernels are made using CUDA and work parallel on GPU. Four morphology operations (erosion, dilation, opening, and closing) using square structuring element are tested on MRI images with different size to measure the speedup of the GPU implementation over CPU implementation. The results show that the speedup of dilation is similar for all kernels. However, on erosion, opening, and closing, shared kernel works faster than other kernels.

• 통상정보연구
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• 제10권4호
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• pp.203-219
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• 2008

This study shows the following results. First, the assessment items of the whole exhibition operation, workforce, counselor's ability, facility and environment were important analysis factors for exhibition recognition, quality of human operation and quality of exhibition facility and environment. Second, exhibition recognition was found to be the most significant factor that influenced exhibitor's cognitive achievement, exhibition employee operation and exhibition facility. Third, exhibitors' satisfaction simultaneously increased as exhibition recognition and employee operation quality were raised. However, exhibition facility didn't strongly influence exhibitors' satisfaction. Fourth, high exhibition recognition, employee operation and exhibition facility resulted in high cognitive achievement and exhibitor's loyalty. Fifth, exhibition recognition is a highly influential factor to mediate exhibitor's cognitive achievement and exhibitors' loyalty. It implied that exhibitors' cognitive achievement and satisfaction were significantly related to the exhibition quality factor. Moreover, it indicated the effective and efficient operational method to strengthen promotional strategy, enhance the quality of employee operation, exhibition facility and environment. Thus, the results suggest a new method to evaluate exhibitor's satisfaction in the exhibition industry.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.341-343
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• 2012

This study introduces a method for computation of process and operation gap in the specific construction operation(i.e., RC frame construction applying a block-grouping scheme) using CYCLONE-based simulation modeling and analysis technique. Since uncertainty of construction environment exists, a thoughtful production planning is required to effectively deal with a risk resulting in schedule delay in advance. This study presents the concepts of a time delay occurred in a process level and operation level in a operation model, and a method of measuring gap-times in each level while the simulation progresses. It helps a site manager to decide how many segmentation in a construction block is suitable for eliminating unproductive time-delays under the constrained resources (e.g., laborer, equipment). A case study presents a network model representing a three segmented RC frame work, and result obtained from the simulation experiment.