• 한국수자원학회:학술대회논문집
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• 한국수자원학회 1998년도 학술발표회 논문집
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• pp.203-208
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• 1998

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권7호
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• pp.363-368
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• 1999

The parallel operation system of multiple uninterruptible power supplies(UPSs) is used to increase power capacity of the system or to secure higher reliability at critical loads. In the parallel operation of the two UPSs, the load-sharing control to maintain the current balance between them is a key technique. Because a UPS has low output impedance and quick response characteristics, in case of an unbalanced load inverter output current changes very rapidly and thereby can instantaneously reach an overload condition. In this study, high precise load-sharing controller is proposed and implemented for the parallel operation system of two UPSs with low impedance characteristics and this controller controls the frequency and the voltage to minimize the active power component and the reactive power component which are gotten from the current difference between two UPSs. And then a good performance of the proposed method is verified by experiments in the parallel operation system with two 40KVA UPSs.

• 전기학회논문지
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• 제62권10호
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• pp.1361-1367
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• 2013

This paper describes and suggests the data visualization for real time power system operation based on energy management system. Because real time power system operation performs analysis of the vast amount of on-line data, the operators need intuitive data visualization to find out useful information in the big data. Especially, in emergency situation, the data visualization is able to assist the operators in handling the crisis quickly and efficiently. Therefore, this paper aims to improve displays of output of real time power system operation by visualizing on-line big data. Through this study, we can develop improved visualization technique for real time power system operation, which has highly readable displays of output and intuitive information.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.341-343
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• 2012

This study introduces a method for computation of process and operation gap in the specific construction operation(i.e., RC frame construction applying a block-grouping scheme) using CYCLONE-based simulation modeling and analysis technique. Since uncertainty of construction environment exists, a thoughtful production planning is required to effectively deal with a risk resulting in schedule delay in advance. This study presents the concepts of a time delay occurred in a process level and operation level in a operation model, and a method of measuring gap-times in each level while the simulation progresses. It helps a site manager to decide how many segmentation in a construction block is suitable for eliminating unproductive time-delays under the constrained resources (e.g., laborer, equipment). A case study presents a network model representing a three segmented RC frame work, and result obtained from the simulation experiment.

• Journal of Preventive Medicine and Public Health
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• 제39권5호
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• pp.433-437
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• 2006

Objectives: The aim of this study is to develop a methodology for estimating a nationwide statistic for hernia operations with using the claim database of the Korea Health Insurance Cooperation (KHIC). Methods: According to the insurance claim procedures, the claim database was divided into the electronic data interchange database (EDI_DB) and the sheet database (Paper_DB). Although the EDI_DB has operation and management codes showing the facts and kinds of operations, the Paper_DB doesn't. Using the hernia matched management code in the EDI_DB, the cases of hernia surgery were extracted. For drawing the potential cases from the Paper_DB, which doesn't have the code, the predictive model was developed using the data mining technique called SEMMA. The claim sheets of the cases that showed a predictive probability of an operation over the threshold, as was decided by the ROC curve, were identified in order to get the positive predictive value as an index of usefulness for the predictive model. Results: Of the claim databases in 2004, 14,386 cases had hernia related management codes with using the EDI system. For fitting the models with applying the data mining technique, logistic regression was chosen rather than the neural network method or the decision tree method. From the Paper_DB, 1,019 cases were extracted as potential cases. Direct review of the sheets of the extracted cases showed that the positive predictive value was 95.3%. Conclusions: The results suggested that applying the data mining technique to the claim database in the KHIC for estimating the nationwide surgical statistics would be useful from the aspect of execution and cost-effectiveness.

• 한국멀티미디어학회논문지
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• 제15권11호
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• pp.1284-1291
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• 2012

선박 객체 검출 기술은 입력된 비디오 및 영상 데이터에서 선박 객체가 존재하는 경우 선박의 위치를 검출하는 기술로서 입력 영상의 환경 변화와 잡음의 영향에 따라서 검출 정확도의 편차가 높다. 이런 문제점을 해결하기 위하여 본 논문에서는 배경 구축 기법과 형태학적 연산 기반의 다중 선박 객체 검출 기술을 제안한다. 제안하는 방법은 배경 제거 단계, 잡음 제거 단계, 객체 기준 위치 설정 단계, 객체 재구성 단계, 다중 객체 검출 단계 등 5단계를 거쳐서 선박을 검출한다. 다양한 변수를 고려한 15가지 실험 비디오를 대상으로 한 실험을 통해서 98.7%의 검출율을 나타내었으며, 환경 변화에 강인한 검출을 수행하는 것을 확인할 수 있었다. 제안하는 방법은 해상 관제와 선박 자동 운항 기술의 기반 기술로서 유용하게 사용될 수 있다.

• 대한의용생체공학회:의공학회지
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• 제27권6호
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• pp.392-401
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• 2006

Image Guided Surgery (IGS) system which has variously tried in medical engineering fields is able to give a surgeon objective information of operation process like decision making and surgical planning. This information is displayed through 3D images which are acquired from image modalities like CT and MRI for pre-operation. The technique of image registration is necessary to construct IGS system. Image registration means that 3D model and the object operated by a surgeon are matched on the common frame. Major techniques of registration in IGS system have been used by recognizing fiducial markers placed on the object. However, this method has been criticized due to additional trauma, its invasive protocol inserting fiducial markers in patient's bone and generating noise data when 2D slice images are acquired by image modality because many markers are made of metal. Therefore, this paper developed shape-based registration technique to improve the limitation of fiducial marker based IGS system. Iterative Closest Points (ICP) algorithm was used to match corresponding points and quaternion based rotation and translation transformation using closed form solution applied to find the optimized cost function of transformation. we assumed that this algorithm were used in Total Knee replacement (TKR) operation. Accordingly, we have developed region-based 3D registration technique based on anatomical landmarks and this registration algorithm was evaluated in a femur model. It was found that region-based algorithm can improve the accuracy in 3D registration.

• 대한족부족관절학회지
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• 제18권3호
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• pp.115-118
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• 2014

Purpose: The purpose of this study is to report on the result of repairing Achilles tendon using absorbable suture under nerve block. Materials and Methods: We retrospectively reviewed 20 patients with acute Achilles tendon rupture who were followed up for at least six months after the operation. We repaired Achilles tendon using two absorbable sutures using the Krackow technique for the proximal stump and the Kessler technique for the distal stump. A programmed postoperative management including non-weight bearing with a short leg cast for four weeks after the operation was applied for all patients. We evaluated clinical results using American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, visual analogue scale (VAS) for satisfaction, range of motion of ankle, functional recovery rate, and the starting time of single heel raise. Results: The mean VAS score for satisfaction and AOFAS score was 9.2 and 93.0, respectively. The affected ankle showed a mean dorsiflexion rate of 90% and plantar-flexion rate of 94% compared to the uninjured side. The single heel raise could start at a mean of 3.5 months after the operation. Conclusion: Treatment of Achilles tendon rupture with absorbable suture material using the hybrid suture technique of proximal Krackow and distal Kessler showed sufficient stability and minimal chronic inflammatory reaction.

• 사물인터넷융복합논문지
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• 제8권5호
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• pp.77-83
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• 2022

낸드 플래시 메모리는 구조적으로 쓰기 전 지우기(Erase-Before-Write) 동작이 요구된다. 이것을 해결하기 위해서는 데이터 업데이트 동작이 빈번히 발생하는 페이지(Hot data page)를 구분하여 별도에 블록에 저장함으로 해결할 수 있으며 이러한 Hot data를 분류하는 기법을 핫 데이터 판단기법이라 한다. MHF(Multi Hash Function Framework)기법은 데이터 갱신요청의 빈도를 시스템 메모리에 기록하고 그 기록된 값이 일정 기준 이상일 때 해당 데이터 갱신요청을 Hot data로 판단한다. 하지만 데이터 갱신요청에 빈도만을 단순히 카운트하는 방법으로는 정확한 Hot data로 판단에 한계가 있다. 또한 데이터 갱신요청의 지속성을 판단 기준으로 하는 기법의 경우 갱신요청 사실을 시간 간격을 기준으로 순차적으로 기록한 뒤 Hot data로 판단하는 방법이다. 이러한 지속성을 기준으로 하는 방법의 경우 그 구현과 운용이 복잡한 단점이 있으며 갱신요청에 빈도를 고려하지 않는 경우 부정확하게 판단되는 문제가 있다. 본 논문은 데이터 갱신요청에 빈도와 지속성을 함께 고려한 경량화된 핫 데이터 판단기법을 제안한다.

• Structural Engineering and Mechanics
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• 제9권3호
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• pp.215-226
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• 2000

Computational procedure within the framework of return mapping technique has been presented to integrate the constitutive behavior of a concrete model. Developed by Ohtani and Chen, this concrete model is based on multiple hardening concept, and is rate-independent and associative. Consistent tangent operator suitable for finite element analysis is derived to preserve the rate of convergence. Accuracy of the integration technique is verified and compared with available experimental data. Computational efficiency is demonstrated by comparing with results based on elasto-plastic tangent.