• International Journal of Railway
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• 제9권1호
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• pp.10-14
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• 2016

Life cycle cost analysis is compulsively required for the system operation. System operation costs are consisted of acquisition, operation, maintenance and so on. In the beginning of the system planning, we need to take into account of various costs following the system operating. To implement LCC, we need to analyze system life cycle to identify all costs during system life. The costs can be divided into three parts. The first part is purchasing cost, the second for operating cost and the last for disposal cost. The second operating cost can be decomposed of operating cost included labor, energy consumption cost for system running, maintenance costs to keep systems healthy, delay cost caused from maintenance and hazard cost, and so on. In this paper, we carried out for railway locomotives which operate over more 30years and which cost about 10 million USD. We decompose the life cycle of the locomotives and break down the locomotives into subsystems to require maintenance or not, and subsystems to need energy or not. We showed how to decide optimal locomotives through cost identification and system breakdown.

• 산업경영시스템학회지
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• 제33권3호
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• pp.63-70
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• 2010

Based on the known results of the expected busy periods for the triadic Min (N, T, D) and Max (N, T, D) operating policies applied to a controllable M/G/1 queueing model, a relation between them is constructed. Such relation is represented in terms of the expected busy periods for the simple N, T and D, and the dyadic Min (N, T), Min (T, D) and Min (N, D) operating policies. Hence, if any system characteristics for one of the two triadic operating policies are known, unknown corresponding system characteristics for the other triadic operating policy could be obtained easily from the constructed relation.

• 산업경영시스템학회지
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• 제37권1호
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• pp.96-103
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• 2014

A steady-state controllable M/G/1 queueing model operating under the (TN) policy is considered where the (TN) policy is defined as the next busy period will be initiated either after T time units elapsed from the end of the previous busy period if at least one customer arrives at the system during that time period, or the time instant when Nth customer arrives at the system after T time units elapsed without customers' arrivals during that time period. After deriving the necessary system characteristics such as the expected number of customers in the system, the expected length of busy period and so on, the total expected cost function per unit time in the system operation is constructed to determine the optimal operating policy. To do so, the cost elements associated with such system characteristics including the customers' waiting cost in the system and the server's removal and activating cost are defined. Then, the optimal values of the decision variables included in the operating policies are determined by minimizing the total expected cost function per unit time to operate the system under consideration.

• Advances in Energy Research
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• 제4권3호
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• pp.239-253
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• 2016

Air quality in hospitals has always concerned hospitals' health officials due to its dangerous particles and gases. Because of the importance of air conditioning in the operating room, a system must be embedded in operating rooms to direct the contaminated air outside, and inject fresh filtered air from outside back into the room. In this study, laminar flow air conditioning system is implemented in the operating room by slot linear diffusers and with the help of air curtain. For this, stimulation Computational Fluid Dynamic (CFD) was used due to its efficiency. The aim of the present study was to find a proper solution to overcome the unfavorable factors, namely, contamination, humidity, and also temperature, velocity and pressure inside the room. These factors were implemented with different values and then stimulated through FLUENT software program. Results showed that the aforementioned factors can be overcome using air curtain and slot linear diffusers.

• 대한임베디드공학회논문지
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• 제11권6호
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• pp.335-341
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• 2016

As information technology advances rapidly, various smart devices are becoming an essential element in our lives. Smart devices are providing services to users through applications up on the operating system. Operating systems have a variety of rules, such as scheduling applications and controlling hardwares. Among those rules, it is significant to protect private information in the information-oriented society. Therefore, isolation task, that makes certain memory space separated for each application, should highly be guaranteed. However, modern operating system offers the function to access the memory space from other applications for the sake of debugging. If this ability is misused, private information can be leaked or modified. Even though the access authority to memory is strictly managed, there exist cases found exploited. In this paper, we analyze the problems of the function provided in the Android environment that is the most popular and opened operating system. Also, we discuss how to avoid such kind of problems and verify with experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1840-1845
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• 2005

The SoC and digital technology development recently enabled the emergence of information devices and control devices because the SoC present many advantages such as lower power consumption, greater reliability, and lower cost. It is required to use an embedded operating system for building control systems. So far, the Real-Time operating system is widely used to implement a Real-Time system since it meets developer's requirements. However, Real-Time operating systems reveal a lack of standards, expensive development, and license costs. Embedded Linux is able to overcome these disadvantages. In this paper, the implementation of control system platform using Real-Time Embedded Linux is described. As a control system platform, we use XScale of a Soc and build Real-Time control platform using RTAI and Real-Time device driver. Finally, we address the feasibility study of the Real-Time Embedded Linux as a Real-Time operating system for mobile robots.

• 한국레이저가공학회지
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• 제18권4호
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• pp.12-16
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• 2015

The research on multi electron beam systems is being carried out by various methods. We are studying multi electron beam system using miniaturized electron beam columns. The column consists of electrostatic lenses, electrostatic deflector and tip emitter. Our operating system controls 4 column array, captures images of each column and maintains the instrument. We present the usefulness of our operating system for multi columns by capturing images of each column.

• 정보보호학회논문지
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• 제16권2호
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• pp.55-70
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• 2006

본 논문에서는 유연한 접근통제를 제공하는 보안 운영체제에 적합한 새로운 접근통제 보안구조를 제안한다. 제안된 보안구조는 가상 접근통제 시스템을 추가하여 다양한 접근통제모델을 보안 운영체제에 쉽게 적용할 있는 특성을 제공한다. 또한, 기존의 리눅스 시스템의 표준 접근통제의 단점을 극복하기 위해 설계되었으며, 유연하게 보안모델들을 조합할 수 있을 뿐만 아니라 동적으로도 보안모델들을 적용할 수 있다. 제안된 접근통제 보안구조는 접근통제집행부분과 접근통제결정 부분, 보안제어부분으로 분리되고, 가상 접근통제 시스템에 의해 접근통제 모델들은 계층적 구조로 추상화된다. 그리고 다양한 접근통제 모델을 적용함으로써 발생하는 정책충돌의 개념과 해결방법을 제시한다.

• 수산해양기술연구
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• 제59권1호
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• pp.74-84
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• 2023

This paper is the result of a comparative analysis of crew members' workloads using the EMG and OWAS methods according to the fishing process before and after the improvement of the operating system of the experimental vessel, with the aim of improving operational efficiency and safety work of coastal improved stow net fishing vessels. The target crew members were three people with at least five years of experience on board the same fishing vessel as the experimental vessel. After improving the operating system, such as installing a power block crane and two capstans, change the location of the ball-roller, the time required for setting and hauling work decreased (p < .01), and the evaluation results by OWAS showed that the overall workload for setting and hauling net work decreased. The results of muscle activity analysis showed a decrease in lashing anchor work (p < .01) in the case of hauling net and in anchor dropping work in the case of setting net (p < .001). It is judged that the use of ball rollers in net handling has been reduced; consequently, work safety has been improved.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.663-668
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• 2006

In the present paper, a single stage fresh water generator was modified and extended to 2 effect desalination system. The inlet temperatures of hot water and feed water were selected as experiment parameters to get operating conditions and fresh water generating rates. The impacts of these parameters on operating conditions and fresh water generating rates were described in detail.