• Journal of information and communication convergence engineering
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• 제10권4호
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• pp.372-377
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• 2012

In this paper, we propose an implementation of a real-time operating system for the two-wheel mobile robot. With this implementation, we have the ability to control the complex embedded systems of the two-wheel mobile robot. The advantage of the real-time operating system is increasing the reliability and stability of the two-wheel mobile robot when they work in critical environments such as military and industrial applications. The real-time operating system which was ported to this implementation is open systems and the corresponding interfaces for automotive electronics (OSEK/VDX). It is known as the set of specifications on automotive operating systems, published by a consortium founded by the automotive industry. The mechanical design and kinematics of the two-wheel mobile robot are described in this paper. The contributions of this paper suggest a method for adapting and porting OSEK/VDX real-time operating system to the two-wheel mobile robot with the differential drive method, and we are also able to apply the real-time operating system to any complex embedded system easily.

• Journal of Biosystems Engineering
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• 제31권1호
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• pp.39-45
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• 2006

Fundamental informations on performance of sets of solenoid valve and nozzle were necessary to develop a target selectable spraying system. The experiments were performed for the sets of solenoid valves and flat spraying nozzles at 3 levels of the operating pressures, and the obtained results are as follows; Rise time of the system pressure to reach up to 90% of the operating pressure after the valve turned was affected by nozzle size and operating pressure. Maximum overshoot of the system pressure was about 170% not affected by the sets of valve and nozzle and operating pressure. The system pressure after its settle down within 5% of the set pressure showed good uniformity in any condition of the experiment as less as 2.3% of its coefficient of variation. Time requirement to lower the system pressure down to 50% after the valve power turned off was affected by valve and nozzle set and operating pressure.

• 한국수소및신에너지학회논문집
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• 제23권6호
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• pp.604-611
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• 2012

For the commercialization of fuel cell powered vehicle, it is highly important to improve the performance and efficiency of an automotive polymer electrolyte membrane fuel cell (PEMFC) system. The performance and efficiency of PEMFC systems are significantly influenced by their operating conditions. Among these conditions, the system operating pressure is considered as the one of the main factors. In this study, to investigate the effects of operating pressure on the performance and efficiency of automotive PEMFC systems, two types of high-pressure operating PEMFC systems adopting two different compressors (i. e. different performance maps) are modeled by using MATLAB/Simulink environment. The PEMFC system efficiency and parasitic compressor power are mainly analyzed and compared for the two types of high-pressure operating PEMFC systems under the same system net power conditions. It is expected that this kind of study can contribute to provide basic insight into the operating strategies of high-pressure operating PEMFC systems for automotive use.

• 전기학회논문지
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• 제62권4호
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• pp.444-450
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• 2013

This paper presents the criteria for setting the dynamic operating mode of BESS(Battery Energy Storage System) in the bulk power systems. ESS has been expected to improve the degraded dynamic performance of the power system with high penetration of the renewable resources. While ESS is controlled in steady state or dynamic operating mode for its better effectiveness depending on the operating conditions of power systems, the criteria for setting the dynamic operating mode for the transient period needs to be robust enough to cover all the different conditions. The proposed criteria consider the varying conditions and the operating practices of the bulk power systems.

• 산업공학
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• 제15권4호
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• pp.364-373
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• 2002

This paper developed an operating software for the manufacturing cell of a model plant. The model plant, which was manufactured by Fishertechnik, consists of an assembly cell, a machining cell, and supplementary material handling equipments. Each I/O module of the model plant communicates with the INTERBUS controller devices via High-level Language Interface(HLI). The machining center has two machining cells, which consists of 4 machines respectively, two 3-axis portal transporters, and a rail guided vehicle(RGV). The Petri-Net was used to investigate the dynamics of each machining cell, e.g., the relation of material handling equipments and machines. The operating software was analyzed and designed by Object Oriented Technique. The software was implemented using Delphi 3.0 under Windows 95/NT operating system.

• 대한안전경영과학회지
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• 제19권3호
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• pp.27-33
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• 2017

Electrical product safety certification is for public safety. Korea electrical safety certification (KC) is being tested and certified on the base of Korean electrical appliance safety act and KC scheme. There are operating system and Electrical safety standards in the KC scheme. KC' operating system was adapted from japan operating system of Japan certification scheme. But KC certification' electrical safety standard was adapted from IEC standards of IECEE CB scheme. So There are many problems such as difference of version between KC standards and IEC standards, discrepancy between operating system and standards. Therefore, This paper analyzed the reason of discrepancy and proposed the improved KC certification operating system in order to reduce cost and to save time in the procedure of issuing KC approval for public safety in using electrical products and also for global competence.

• 한국수소및신에너지학회논문집
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• 제30권5호
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• pp.401-410
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• 2019

The operating conditions greatly impact the efficiency and performance of polymer electrolyte membrane (PEM) fuel cell systems and must be properly managed to ensure better performance and efficiency. In particular, small variations in operating conditions interact with each other and affect the performance and efficiency of PEM fuel cell systems. Thus, a systematic study is needed to understand how small changes in operating conditions affect the system performance and efficiency. In this paper, an automotive fuel cell system (including cell stack and balance of plant [BOP]) with a turbo-blower was modeled using MATLAB/Simulink platform and the sensitivity analyses of main operating parameters were performed using the developed system model. Effects of small variations in four main parameters (stack temperature, cathode air stoichiometry, cathode pressure, and cathode relative humidity) on the system efficiency were investigated. The results show that cathode pressure has the greatest potential impact on the sensitivity of fuel cell system efficiency. It is expected that this study can be used as a basic guidance to understand the importance of achieving accurate control of the fuel cell operating conditions for the robust operation of automotive PEM fuel cell systems.

• 한국지열·수열에너지학회논문집
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• 제12권1호
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• pp.17-22
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• 2016

It is very important to obtain a out-of season production in horticultural greenhouses corresponding with higher crop prices. A ground source heat pump system has been highly spotlighed as an energy efficient heating system for the greenhouse. This paper investigated the operating cost of the ground source heat pump system with the variation of generating temperature and designing methods for heating system of the greenhouse. Even though the COP of the ground source heat pump system decreased with an increment of generating temperature in heating mode, the operating cost could be reduced. By adopting the high temperature heat pump system and heat storage tank, it could be achieved to save energy and reduce the operating time of auxiliary oil heating system for producing good plant-growth in the greenhouse.

• 한국태양에너지학회 논문집
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• 제35권3호
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• pp.49-56
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• 2015

This paper presents a comparative operating characteristics of static var compensator(SVC) and static synchronous compensator(STATCOM) for compensating the reactive power in the Jeju power system. There are two kinds of reactive power compensating systems, which are active and passive system in the applications of the line commutated converter type high voltage direct current (LCC-HVDC). In the Jeju power system, two STATCOMs as active compensating system have been operating. Even though STATCOM has good performance compared with SVC, economical efficiency of former system is not good to the latter system. So, it is necessary to examine the performance and economical efficiency depend on the intention before appling the system. To compare the operating characteristics of two systems in the Jeju power system, simulations have been carried out for case studies that both of the HVDC system have transient state by using PSCAD/EMTDC program.

• 동아시아경상학회지
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• 제12권1호
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• pp.35-42
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• 2024

Purpose: A railroad project is a complex system with large construction costs in the initial stage and ongoing operating costs over its lifecycle. Current railroad projects tend to be based on construction options, which leads to huge deficiencies in operating costs. This phenomenon results from a lack of appropriate tools to accurately estimate a railroad project's lifecycle costs. This study attempts to analyze the major components of railroad operating costs and to propose a decision-making system for analyzing the long-term lifecycle costs of railroad projects. Research design, data and methodology: We review the literature and analyze the current status of railroad operating costs in Korea and overseas. Based on previous projects, a framework for project options and operating costs is proposed. The framework is applied to actual railroad projects to demonstrate the validity of the model. Results: Case analysis shows that our framework is comprehensive in analyzing the primary aspects of railroad operating costs and plays an effective role in choosing various railroad project options. This study points out that the railway project operates inefficiently because estimating long-term costs without reflecting specific project options causes many errors. Conclusions: A major contribution of this study is the development of an improved framework for accurately estimating operating costs and providing policymakers and engineering firms with a holistic decision support system. Detailed components in estimating operating costs of the railroad business are discussed. And we present a decision-making tool that policymakers and private businesses can use in planning the railroad business.