• 산업기술연구
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• 제21권B호
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• pp.223-232
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• 2001

This study is finding the most appropriate model of kangwondo watershed. To synthesize each hydrograph, It is found to several parameters which are used in existing hydrographes. then the synthestic hydrograph is compared and investigated with many hydrographes of the rivers in kanwondo. These methods, Nakayasu, Clark, SCS are used to calculate the run-off of this watershed. When the calculated run-off is compared with real rating-curves, then it is found that the SCS method using the Clark's concentrantion time is the best way on this area having large watershed, long river length and gentle water slope, the Nakayasu method is more suitable on this area having small watershed, short river length and steep water slope. Also it is founded from analyzing run-off hydrographes, peak run-off and peak time that the Clark's method applied Kirpich's concentration time way is suitable in the area of kangwondo.

• 대한기관윤리심의기구협의회지
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• 제3권1호
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• pp.11-18
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• 2021

Purpose: The purpose of this study is to investigate a satisfaction survey of untact education and platforms that can be used for untact education to provide recommendations on future development of Education of Persons Conducting Clinical Trials. Methods: Online survey was distributed among students who have taken Untact Education of Persons Conducting Clinical Trials. The result was separated according to topic and descriptive statistics was used for analysis. The satisfaction survey used 10-point scale. Results: Of the 1,720 students who received the survey, 1,347 (78.3%) responded to the lecture satisfaction survey. The satisfaction level for broadcasting program (Kakao TV), an untact educational platform for the education of clinical trial workers at Kyung Hee University Medical Center, was relatively high with 8.09±1.99 points. Average score respondents recommending Kyung Hee University Untact Education of Persons Conducting Clinical Trials was 8.03±1.83 and customer recommendation score (Net Promotor Score) was 27.1%. Satisfaction level of the preferred training time was divided into weekday-morning (8-11 AM) (8.16±1.75), weekday-afternoon (12-4 PM) (7.73±2.07), weekday-evening (5-9 PM) (7.78±2.22), and weekend-morning (9-11 AM) real-time untact education (8.48±1.76) and analyzed. There was a noticeable difference between weekend-morning and weekday-afternoon (p<0.0001) and weekend-morning and weekday-evening (p=0.0001) real-time untact education. When asked about conducting education after COVID-19 pandemic ends, 79.2% (1,012 of 1,279) of the respondents answered that they prefer real-time untact education while 20.8 % (266 of 1,279) preferred face-to-face education. Conclusion: Online education, without time and space constraint, is expected to be the mainstream market in Korea for Education of Persons Conducting Clinical. Kyung Hee University Untact Education of Persons Conducting Clinical has achieved above average satisfaction using Kakao TV. Kyung Hee University Real-time Untact Education of Persons Conducting Clinical Net Promotor Score is 27.1%, which is above industry average, communication with trainees should be considered to improve Net Promotor Score.

• 산업경영시스템학회지
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• 제20권43호
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• pp.153-162
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• 1997

M/G/1 queueing system is one of the most widely used one to model the real system. When operating a real systems, since it often takes cost, some control policies that change the operation scheme are adopted. In particular, the N-policy is the most popular among many control policies. Almost all researches on queueing system are based on the assumption that the arrival rates of customers into the queueing system is constant, In this paper, we consider the M/G/1 queueing system whose arrival rate varies according to the servers status : idle, set-up and busy states. For this study, we construct the steady state equations of queue lengths by means of the supplementary variable method, and derive the PGF(probability generating function) of them. The L-S-T(Laplace Stieltjes transform) of waiting time and average waiting time are also presented. We also develop an algorithm to find the optimal N-value from which the server starts his set-up. An analysis on the performance measures to minimize total operation cost of queueing system is included. We finally investigate the behavior of system operation cost as the optimal N and arrival rate change by a numerical study.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권5호
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• pp.311-321
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• 2003

In an emergency telemedicine system such as the High-quality Multimedia based Real-time Emergency Telemedicine(HMRET) service, it is very important to examine the status of the patient continuously using the multimedia data including the biological signals(ECG, BP, Respiration, $SpO_2)$ of the patient. In order to transmit these data real time through the communication means which have the limited transmission capacity, it is also necessary to compress the biological data besides other multimedia data. For this purpose, we investigate and compare the ECG compression techniques in the time domain and in the wavelet transform domain, and present an effective lossless compression method of the biological signals using PEG Huffman table for an emergency telemedicine system. And, for the HMRET service, we developed the lossless compression and reconstruction program or the biological signals in MSVC++ 6.0 using DPCM method and JPEG Huffman table, and tested in an internet environment.

• 한국전자통신학회논문지
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• 제5권4호
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• pp.399-405
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• 2010

본 논문에서는 기존의 문제점인 얼굴 움직임이 있을 시 시선 식별이 어려운 점과 사용자에 따른 교정작업이 필요하다는 점을 해결하고자 새로운 시선 식별 시스템을 제안한다. Kalman필터를 사용하여 현재 머리의 위치정보를 이용하여 미래위치를 추정하였고 얼굴의 진위 여부를 판단하기 위해서 얼굴의 특징요소를 구조적 정보와 비교적 처리시간이 빠른 수평, 수직 히스토그램 분석법을 이용하여 얼굴의 요소를 검출한다. 그리고 적외선 조명기를 구성하여 밝은 동공효과를 얻어 동공을 실시간으로 검출, 추적하였고 동공-글린트 벡터를 추출한다.

• 산업경영시스템학회지
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• 제35권1호
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• pp.1-9
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• 2012

It is well known that internet shoppers are very sensitive to sale prices. They visit the various shopping malls and collect the product information including purchase conditions for goods purchase decision-making. Recently the necessity of information support is increasing because of increase of information amount which is necessary and complexity of goods purchase decision-making process. The comparison shopping agent systems have provided price comparison information which is collected from various shopping malls to satisfy internet shoppers information craving. But the frequent price change caused by keen price competition is becoming the primary reason of information quality decline among price comparison sites. RSS which is a family of web feed formats used to publish frequently updated is applied even in on-line shopping malls. This paper develops a RSS product information collection system to get real-time product information. The proposed product information system consists of (1) web crawler module for searching RSS feed shopping malls automatically, (2) RSS reader module for parsing product information from RSS feed file, (3) product DB and (4) product searching module. Performance of the proposed system is higher than the comparison shopping agent systems when it is defined with the volume of collecting product information per unit time.

• Design & Manufacturing
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• 제17권3호
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• pp.34-40
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• 2023

In this study, real-time collection of mold vibration signals during injection molding processes was achieved through IoT devices installed on the mold surface. To analyze changes in the collected vibration signals, injection molding was performed under six different process conditions. Analysis of the mold vibration signals according to process conditions revealed distinct trends and patterns. Based on this result, cosine similarity was applied to compare pattern changes in the mold vibration signals. The similarity in time and acceleration vector space between the collected data was analyzed. The results showed that under identical conditions for all six process settings, the cosine similarity remained around 0.92±0.07. However, when different process conditions were applied, the cosine similarity decreased to the range of 0.47±0.07. Based on these results, a cosine similarity threshold of 0.60~0.70 was established. When applied to the analysis of mold vibration signals, it was possible to determine whether the molding process was stable or whether variations had occurred due to changes in process conditions. This establishes the potential use of cosine similarity based on mold vibration signals in future applications for real-time monitoring of molding process changes and anomaly detection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.2977-2997
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• 2018

In big data era, fresh data grows rapidly every day. More than 30,000 gigabytes of data are created every second and the rate is accelerating. Many organizations rely heavily on real time streaming, while big data stream computing helps them spot opportunities and risks from real time big data. Storm, one of the most common online stream computing platforms, has been used for big data stream computing, with response time ranging from milliseconds to sub-seconds. The performance of Storm plays a crucial role in different application scenarios, however, few studies were conducted to evaluate the performance of Storm. In this paper, we investigate the performance of Storm under different application scenarios. Our experimental results show that throughput and latency of Storm are greatly affected by the number of instances of each vertex in task topology, and the number of available resources in data center. The fault-tolerant mechanism of Storm works well in most big data stream computing environments. As a result, it is suggested that a dynamic topology, an elastic scheduling framework, and a memory based fault-tolerant mechanism are necessary for providing high throughput and low latency services on Storm platform.

• 전자공학회논문지SC
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• 제46권5호
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• pp.22-28
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• 2009

본 논문에서는 다중 상태 시변 시간지연을 가지는 연속시간 특이시스템의 $H_{\infty}$ 필터링 문제를 다룬다. 제안하는 필터의 목적은 필터링 오차 특이시스템(filtering error singular system)이 정규성, 임펄스 프리, 점근적 안정성 및 $H_{\infty}$ 노옴 유계(bound)를 만족하는 선형 필터를 설계하는 것이다. 먼저, 다중 상태 시변 시간지연을 가지는 특이시스템에 대한 새로운 지연종속 유계실수정리(bounded real lemma)를 자승 요소를 기초로 하는 유한 합 부등식(finite sum inequality)을 이용하여 제안하고, 이로부터 $H_{\infty}$ 필터가 존재할 조건과 필터의 설계기법을 최적화가 가능한 선형행렬부등식(linear matrix inequality)으로 제시한다. 마지막으로 예제를 통하여 제안한 필터 설계 알고리듬의 타당성을 확인한다.

• 컴퓨터교육학회논문지
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• 제11권1호
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• pp.23-32
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• 2008

본 논문에서는 논리회로 실험용 장비 사용법 및 실험 내용에 대한 교육용 멀티미디어 콘텐츠로 구성된 논리회로 가상실험실이 실제 실험 교육에 끼치는 교육효과를 조사하였다. 대학 저학년의 공학 실험의 경우, 실험 회로 및 실험 장비 사용법에 대한 사전 이해가 절실히 요구된다. 그러나 기존의 전통적인 실험환경에서는 실험 장비 사용법 교육의 경우, 장비에 대한 접근성이 제한되어 있고, 짧은 실험시간 내에 다양한 기능을 설명하기에는 많은 제약이 있으며, 실험회로의 다양한 동작에 대한 경험은 실제 실험에서나 가능한 문제점이 있다. 본 논문에서 구현한 논리회로 가상실험실에서는 실제 실험 전에 실습자에게 실제 실험과 같은 환경을 제공하여 사전에 실험 준비를 할 수 있도록 한다. 가상실험실을 활용한 집단과 그렇지 않은 집단인 30명 단위의 두 실험 집단에 대해 가상실험실의 교육효과를 조사한 결과, 가상실험실을 활용한 집단이 한 학기 실험과정에서 평균 8.2% 정도의 실험시간 단축을 보였다.