• 조명전기설비학회논문지
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• 제27권3호
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• pp.65-78
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• 2013

To analyze influences under open fault conditions in switching devices, an integrated simulation and condition monitoring scheme for a permanent magnet synchronous generator (PMSG) based variable speed grid-connected wind turbine system are presented. Among various faults in power electronics components, the open fault in switching devices may arise when the switches are destructed by an accidental over current, or a fuse for short protection is blown out. Under such a faulty condition, the grid-side inverter as well as the generator-side converter does not operate normally, producing an increase of current harmonics, and a reduction in output and efficiency. As an effective way for a condition monitoring of generation system by online basis without requiring any diagnostic apparatus, the estimation schemes for generated voltage, flux linkage, and stator resistance are proposed and the validity of the proposed scheme is proved through comparative simulations.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.632-644
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• 2019

The remote monitoring and warning system for dangerous chemicals is designed with the concept of the Cyber-Physical System (CPS) in this paper. The real-time perception, dynamic control, and information service of major hazards chemicals are realized in this CPS system. The CPS system architecture, the physical layer and the applacation layer, are designed in this paper. The terminal node is mainly composed of the field collectors which complete the data acquisition of sensors and video in the physical layers, and the use of application layer makes CPS system safer and more reliable to monitor the hazardous chemicals. The cloud application layer completes the risk identification and the prediction of the major hazard sources. The early intelligent warning of the major dangerous chemicals is realized and the security risk images are given in the cloud application layer. With the CPS technology, the remote network of hazardous chemicals has been completed, and a major hazard monitoring and accident warning online system is formed. Through the experiment of the terminal node, it can be proved that the terminal node can complete the mass data collection and classify. With this experiment it can be obtained the CPS system is safe and effective. In order to verify feasible, the multi-risk warning based on CPS is simulated, and results show that the system solves the problem of hazardous chemicals enterprises safety management.

• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.204-211
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• 2011

To yield high concentrations of protein expressed by genetically modified Escherichia coli, it is important that the bacterial strains are cultivated to high cell density in industrial bioprocesses. Since the expressed target protein is mostly accumulated inside the E. coli cells, the cellular product formation can be directly correlated to the bacterial biomass concentration. The typical way to determine this concentration is to sample offline. Such manual sampling, however, wastes time and is not efficient for acquiring direct feedback to control a fedbatch fermentation. An E. coli K12-derived strain was cultivated to high cell density in a pressurized stirred bioreactor on a pilot scale, by detecting biomass concentration online using a capacitance probe. This E. coli strain was grown in pure minimal medium using two carbon sources (glucose and glycerol). By applying exponential feeding profiles corresponding to a constant specific growth rate, the E. coli culture grew under carbon-limited conditions to minimize overflow metabolites. A high linearity was found between capacitance and biomass concentration, whereby up to 85 g/L dry cell weight was measured. To validate the viability of the culture, the oxygen transfer rate (OTR) was determined online, yielding maximum values of 0.69 mol/l/h and 0.98mol/l/h by using glucose and glycerol as carbon sources, respectively. Consequently, online monitoring of biomass using a capacitance probe provides direct and fast information about the viable E. coli biomass generated under aerobic fermentation conditions at elevated headspace pressures.

• 정보교육학회논문지
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• 제25권3호
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• pp.511-525
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• 2021

본 연구의 목적은 초·중등 교육과정을 지원하기 위한 온라인시스템을 대상으로 사용자 친화적인 경험과 편의성을 제공하기 위한 디자인 가이드라인을 개발하는데 있다. 이를 위해 선행연구 및 해외 교육과정 온라인지원시스템에 대한 우수사례를 분석하였다. 또한, NCIC와 고교학점제 사이트를 중심으로 74명의 모니터단 설문 조사를 통해 UX/UI 사용성 문제와 요구를 도출하였다. 해외사례 분석과 모니터단 설문 결과를 바탕을 도출된 디자인 가이드라인에 대한 초안을 바탕으로 전문가 델파이를 실시하여 타당성을 확보하였다. 본 연구에서는 교육과정에 관련된 과업을 수행하는 온라인지원시스템에 일반적으로 적용될 수 있는 디자인 가이드라인을 도출함으로써, 현재 서비스되고 있는 시스템의 개선 방향을 제시하고 향후 개발될 시스템의 디자인의 방향을 제시하였다는 점에서 의의가 있다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.202-203
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• 2020

Unlike price calculation by cost accounting, which categorizes costs into material costs, labor costs, and miscellaneous expenses to determine the construction budget price, construction cost calculation based on Construction Standard Unit Prices utilizes unit prices extracted from market prices of items from projects already completed to estimate costs of similar construction projects. Although unit price information is collected through construction site surveys to revise these construction standard unit prices every year, but due to the limitations of the site survey method, it is difficult to quickly implement the rapid changes in the construction methods and market prices. As such, an important issue that arose was the identification of work items whose prices need urgent revision. This study conducted research on factors that need to be considered when developing online survey system for monitoring construction site market prices. This study is expected to enhance convenience for users, and provide an efficient data collection and management system for administrators.

• 상하수도학회지
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• 제38권2호
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• pp.109-117
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• 2024

In this study, various pre-treatment methods were evaluated for microalgae separation. These methods aimed to facilitate safe, rapid, and cost-effective online imaging for real-time observation and cell counting. As pre-treatment techniques, heating, chemical hydrolysis, heating combined with chemical hydrolysis, and sonication were employed. The effectiveness of these methods was evaluated in the context of online imaging quality through experimentation on cultivated microalgae (Chlorella vulgaris and Scenedesmus quadricauda). The chemical treatment method was found to be inappropriate for improving image acquisition. The heating pre-treatment method exhibited a drawback of prolonged cell dispersion time. Additionally, the heating combined with chemical hydrolysis method was confirmed to have the lowest dispersion effect for Chlorella vulgaris. Conversely, ultrasonication emerged as a promising technique for microalgae separation in terms of repeatability and reproducibility. This study suggests the potential for selecting optimal pre-treatment methods to effectively operate real-time online monitoring devices, paving the way for future research and applications in microalgae cultivation and imaging.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.427-432
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• 2007

This paper research data and information for market environment of electric power value added service According to research, in USA using power line communication(PLC) and other communication device(ex ZigBee, Wireless and so on) online observation and building district management service were being realized Also, in Japan they are executing online electricity facility Igr monitoring service based on IT basic for checking insulation. Also we conduct a survey of H-SCP concept and demand for electric power value added service of Housewife and Working women. This paper will be used data for revitalizing market circumstance of electric power value added service.

• 정보통신설비학회논문지
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• 제10권4호
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• pp.148-154
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• 2011

This paper presents u-COEX, Ubiquitous-Collaborative Online shopping EXecution system, for small- and mediam- sized business enterprises, based on EPCglobal network. The system is taking advantage of RFID technology promises to optimize the critical processes in the Supply Chain Management. The system consists of five major functions: integrated order management, realtime monitoring and analysis system of sales and inventory, decision support system, integrating with EPCglobal and RFID technology, and u-catalog feature. The prototype implementation was developed for mass electronic market complex and the result revealed the feasibility to be applicable to real market.

• 융합신호처리학회논문지
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• 제10권3호
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• pp.207-213
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• 2009

정수장에서 수도꼭지까지 전체적인 물 공급 체계에서 수돗물의 수질은 먹는 물 기준에 적합해야 하지만 수돗물 공급과정에서 수질 모니터링과 충분한 관리가 이루어지지 않고 있다. 특히 대부분의 소규모 저수조(지하저수조 또는 고가(高架)저수조)의 수도관은 다양한 오염원에 노출되어 있다. 최근의 수질 모니터링 시스템은 몇몇 대형 정수장과 배수지 등에 설치되어 운영하고 있다. 특히 인터넷을 이용한 수질 모니터링은 언제 어디서나 주민들이 확인할 수 있도록 몇몇 지방자치단체에서 채택하고 있다. 이러한 시스템을 구축하는 것은 대규모 시설을 필요로 하기 때문에, 아파트, 공공건물, 소규모 지하저수조 또는 고가저수조와 같은 규모가 적은 물 공급시설에는 제한적으로 적용된다. 본 연구에서는 저렴한 각각의 수질센서 모듈을 집적화하여 개발한 다항목 수질계측기를 이용하여 인터넷에서 운용되는 온라인 모니터링 프로그램을 개발하였다. 저수조 관리자는 온라인으로 먹는 물의 수질 측정값을 모니터링할 수 있다. 제안된 다항목 수질측정기를 집적화하였으며, 저수조의 크기와 관계없이 저가로 다양한 저수조에 쉽게 적용할 수 있는 시스템이다.

• KEPCO Journal on Electric Power and Energy
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• 제2권4호
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• pp.583-588
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• 2016

The high-temperature steam pipes of thermal power plants are subjected to severe conditions such as creep and fatigue due to the power plant frequently being started up and shut down. To prevent critical pipes from serious damage and possible failure, inspection methods such as computational analysis and online piping displacement monitoring have been developed. However, these methods are limited in that they cannot determine the life consumption rate of a critical pipe precisely. Therefore, we set out to develop a life assessment system, based on a three-dimensional piping displacement monitoring system, which is capable of evaluating the life consumption rate of a critical pipe. This system was installed at the "M" thermal power plant in Malaysia, and was shown to operate well in practice. The results of this study are expected to contribute to the increase safety of piping systems by minimizing stress and extending the actual life of critical piping.