• 전기의세계
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• 제32권4호
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• pp.216-223
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• 1983

본고의 내용은 다음과 같다. 1. FMS의 개념 및 일반적system 2. FMS의 대상 3. FMS의 도입과 sensor 4. FMS에서의 work flow 5. FMS의 추세

• 신재생에너지
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• 제16권1호
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• pp.31-40
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• 2020

Most countries in the world are trying to reduce the use of fossil fuels in the production of electricity and replace them with renewable energy technologies. In Korea, there are abundant ocean renewable energy sources that will play an important role in power generation in the future. This paper introduces a new tidal energy converter utilizing flow induced vibration (FIV), which can work efficiently, even in the currents slower than 1.0m/s. All tests were conducted at the Marine Renewable Energy Laboratory at the University of Michigan to examine the effects of the damping ratio of the electric generators on the power outputs and power efficiencies. In these tests, two identical circular cylinders were used, and passive turbulence controllers were applied to the surface of the cylinders to enhance the FIV. The experimental results showed that by using the two cylinders in the FIV, the power output and efficiency reached up to 31 W and 36%, respectively. In particular, the results showed that the power efficiency was higher at the relatively low flow speed (4

• 전기화학회지
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• 제6권1호
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• pp.28-35
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• 2003

상용 유체 전산모사 코드인 FLUENT ver.6.0을 이용하여 직접 메탄을 연료전지의 전기화학적 해석 및 유로 내에서의 유체의 유동특성을 분석하였다 본 전산모사를 통해 유로 내의 유속, 압력, 온도, 농도 및 전류밀도 분포에 대한 다양한 정보를 얻을 수 있었으며, 유로 디자인에 따른 반응물 및 생성물의 유동에 대한 정보로부터 최적의 유로 형태를 결정할 수 있었다. 이와 같은 전산모사 방법을 사용하면 직접 메탄을 연료전지의 전극과 분리판 유로의 구조를 최적화하는데 매우 유리하다.

• 대한안전경영과학회지
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• 제9권6호
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• pp.123-135
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• 2007

In the recent years, the companies have manually recorded a production status in a work diary or have mainly used a bar code in order to collect each process's progress status, production performance and quality information in the production and logistics process in real time. But, it requires an additional work because the worker's record must be daily checked or the worker must read it with the bar code scanner. At this time, data's accuracy is decreased owing to the worker's intention or mistake, and it causes the problem of the system's reliability. Accordingly, in order to solve such problem, the companies have introduced RFID which comes into the spotlight in the latest automatic identification field. In order to introduce the RFID technology, the process flow must be analyzed, but the ASME sign used by most manufacturing companies has the difficult problem when the aggregation event occurs. Hence, in this study, the RFID logistic flow analysis Modeling Notation was proposed as the signature which can analyze the manufacturing logistic flow amicably, and the manufacturing logistic flow by industry type was analyzed by using the proposed RFID logistic flow analysis signature. Also, to monitor real-time information through EPCglobal network, EPCISEvent template by industry was proposed, and it was utilized as the benchmarking case of companies for RFID introduction. This study suggested to ensure the decision-making on real-time information through EPCglobal network. This study is intended to suggest the Modeling Notation suitable for RFID characteristics, and the study is intended to establish the business step and to present the vocabulary.

• 한국항해항만학회지
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• 제37권6호
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• pp.673-680
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• 2013

본 연구는 요트체험 활동 참여자들의 몰입도가 만족도 및 자아존중감에 미치는 영향에 관한 것으로서 우리나라 요트문화 및 레저산업의 대중화 실현에 기초자료를 제공하는데 그 목적이 있다. 이러한 연구 목적을 달성하기 위해 부산 울산 경남지역 주민을 대상으로 해양레저 아카데미 및 해양레저 체험 프로그램에 참여한 경험이 있는 대상자 총 428명을 모집단으로 선정하여 설문조사를 실시하였으며, 자료처리 방법은 빈도분석, 신뢰도분석, 타당도분석, 단순회귀분석, 다중회귀분석을 사용하였다. 이상과 같은 연구방법 및 자료분석의 결과를 통해 도출된 결론은 다음과 같다. 첫째, 요트체험 참가자들의 몰입도는 만족도에 정적인 영향을 미치는 것으로 나타났다. 둘째, 요트체험 참가자의 몰입도는 자아존중감(일반요인, 가정요인, 직장요인, 사회요인)에 정적인 영향을 미치는 것으로 나타났다. 셋째, 요트체험 참가자의 만족도는 자아존중감(일반요인, 가정요인, 직장요인, 사회요인)에 정적인 영향을 미치는 것으로 나타났다.

• 정보처리학회논문지D
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• 제15D권5호
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• pp.691-698
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• 2008

웹사이트의 구조를 표현하고 설계하는 일반적인 방법으로 스토리보드나 사이트 맵 또는 플로우 차트 등을 사용하거나 또는 이들을 조합하여 사용하는 방법이 있다. 그러나 이들은 웹사이트의 전체 구조를 표현하기 어렵고 웹페이지 간의 세부적인 흐름 관계를 표현하기에 부적절한 면이 있다. 이러한 문제점을 다소 해결하기 위하여 EMFG(Extended Mark Flow Graph)를 이용하여 웹사이트를 표현하고 설계하려는 연구가 진행되었다. 그런데 이러한 기존의 연구는 웹사이트의 정적인 부분들을 대부분 표현하였기 때문에 동적인 웹사이트의 인터페이스를 표현하고 설계하기에는 부족한 점이 있다. 그리고 현재 인터넷의 생활화가 가속화되어 감에 따라 웹사이트의 구조가 더욱 다양하고 복잡하게 되었을 뿐 아니라 인터페이스도 많은 부분에서 동적인 부분을 포함하게 되었다. 따라서 본 연구에서는 EMFG를 사용하여 복잡하고 다양한 웹사이트의 구조뿐만 아니라 동적인 인터페이스 - 예를 들어, 시간에 따라 변하는 페이지 구조 또는 마우스 동작에 따라 변하는 페이지 상태나 구조 등 - 를 표현하는 방법을 제시한다. 본 연구가 웹사이트를 설계하는데 많은 도움이 되고, 웹사이트의 유지보수에도 도움이 될 수 있을 것으로 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권1호
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• pp.216-238
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• 2023

In intelligent transportation systems, traffic management is an important task. The accurate forecasting of traffic characteristics like flow, congestion, and density is still active research because of the non-linear nature and uncertainty of the spatiotemporal data. Inclement weather, such as rain and snow, and other special events such as holidays, accidents, and road closures have a significant impact on driving and the average speed of vehicles on the road, which lowers traffic capacity and causes congestion in a widespread manner. This work designs a model for multivariate short-term traffic congestion prediction using SLSTM_AE-BiLSTM. The proposed design consists of a Bidirectional Long Short Term Memory(BiLSTM) network to predict traffic flow value and a Convolutional Neural network (CNN) model for detecting the congestion status. This model uses spatial static temporal dynamic data. The stacked Long Short Term Memory Autoencoder (SLSTM AE) is used to encode the weather features into a reduced and more informative feature space. BiLSTM model is used to capture the features from the past and present traffic data simultaneously and also to identify the long-term dependencies. It uses the traffic data and encoded weather data to perform the traffic flow prediction. The CNN model is used to predict the recurring congestion status based on the predicted traffic flow value at a particular urban traffic network. In this work, a publicly available Caltrans PEMS dataset with traffic parameters is used. The proposed model generates the congestion prediction with an accuracy rate of 92.74% which is slightly better when compared with other deep learning models for congestion prediction.

• 설비공학논문집
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• 제18권9호
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• pp.753-760
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• 2006

The purpose of the present work is to investigate the influence of the refrigerant adulteration by LiBr solution on the cooling capacity and COP for three different types of abso게tion chillers: a single-effect type, a series-flow double-effect type and a parallel-flow with double-effect type. A simulation program has been prepared for the cyclic analysis of absorption chillers. With some assumptions, the calculations have been performed by solving the mass balance equation, energy balance equation and the state equation simultaneously. The range of the LiBr concentration of refrigerant was 0% to 20% in the present study. For the single-effect absorption chiller, the maximum decrease in the cooling capacity was 10% at the 20% of LiBr concentration. For the double-effect chiller, the capacity was decreased by 11.1% for the parallel-flow type and the series-flow type. Also, the COP was reduced by 3.0% in single-effect, 2.8% in series-flow type (SR=0.4) and 2.3% in parallel-flow type.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.46-53
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• 2001

To optimize the intake flow condition in the heavy-duty LPG SI engine, five different swirl ratios of intake port were investigated experimentally by oil spot method, LDV and single cylinder engine test. The flow characteristics near the piston surface were observed by oil spot method and magnitudes of swirl flow were measured quantatively by LDV method in the steady flow rig. The engine performances of various swirl flow were also tested with the heavy-duty LPG SI single cylinder engine. In the results, high swirl ratio, above $R_s$=2.3, was not suitable to develope a stable flame kernel and to produce high engine performance. Especially it was more serious under lean burn conditions, since turbulence intensity was smaller than bulk flow though those are increased together. These results were also confirmed by LDV measurement and oil spot method. On the contrary, low swirl ratio($R_s$=1.3) is not good to propagate a flame since the turbulence intensity and bulk flow are vanished during compression stroke and low swirl ratio has too weak initial energy for stable combustion. Therefore, the of optimized swirl ratio f3r the heavy-duty LPG engine in this work was found around $R_s$=2.0.

• 한국전산유체공학회지
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• 제17권4호
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• pp.1-8
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• 2012

During a reactor normal operation, two parallel 50% capacity cooling pumps circulate primary coolant to remove the fission reaction heat of the reactor through heat exchangers cold by a cooling tower. When one pump is failure, the other pump shall continuously circulate the coolant to remove the residual heat generated by the fuels loaded in the reactor after reactor shutdown. It is necessary to estimate how much flow rate will be supplied to remove the residual heat. We carried out a flow network analysis for the parallel primary pumps based on the piping network of the primary cooling system in HANARO. As result, it is estimated that the flow rate of one pump increased about 1.33 times the rated flow of one pump and was maintained within the limit of the cavitation critical flow.