• 지질공학
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• 제28권1호
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• pp.1-9
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• 2018

We propose a borehole test technique to estimate permeability of rocks in borehole. The borehole tests are hydraulic injection tests such as leak-off test and hydraulic fracturing tests, which are originally conducted for stress or casing integrity assessment and not for permeability measurement. We use one-dimensional radial diffusion equation to interpret fluid injection test results in terms of permeability. We apply this technique to a leak-off test conducted at a depth of 700 m in a wellbore, where rock formation is mudstone. The estimated permeability is at an order of $10^{-16}m^2$, which is somewhat high but within the range reported for mudstones previously. Quantitative rick assessment suggests that an accurate measurement of open hole section length is important to improve reliability of results. More data may be needed to ensure the reliability of this technique. If validated, however, this technique can provide cost-effective estimation of in situ permeability without conducting independent permeability tests in borehole.

• 대한의용생체공학회:의공학회지
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• 제13권3호
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• pp.209-216
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• 1992

A new experimental technique is proposed to localize the flow limiting segment(FLS) during forced expiration. The present technique is based on the pressure drip across FLS and a consequent change in airway resistance, which can provide an accurate and objective location of FLS. During forced expiratory maneuver artificially induced by a strong negative pressure (-100mmHg) applied at the trachea in an anesthetized open chest dog, airway resistance( R) was calculated from air flow and airway pres- sure signals at various airway locations and lung volumes, At the lung volumes above 10 % VC, FLS located in the trachea 6cm lower from the larynx. With the lung volume decreased below 8% VC, FLS jumped upstream to End-3rd generation of the airway. These results were similar with the previous reports from excised dog lungs, which demonstrated the validity of the present technique. Since the present technique provides a more objective measure of FLS location, it would be useful in future studies of expiratory flow limitation.

• Journal of Information Processing Systems
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• 제15권6호
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• pp.1438-1448
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• 2019

We present a new technique, called VED (very effective debugging), for detecting and correcting division by zero errors for all types of .NET application. We use applications written in C# because C# applications are distributed through the internet and its executable format is used extensively. A tool called Immunity Debugger is used to reverse engineer executable code to get binaries of source code. With this technique, we demonstrate integer division by zero errors, the location of the error causing assembly language code, as well as error recovery done according to user preference. This technique can be extended to work for other programming languages in addition to C#. VED can work on different platforms such as Linux. This technique is simple to implement and economical because all the software used here are open source. Our aims are to simplify the maintenance process and to reduce the cost of the software development life cycle.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.757-762
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• 2013

A technique is presented that uses a new guided wave technique for sludge and blockages detection in long-range pipelines. Existing techniques have the limitations that the sludge position needs to be known a priori and the area to be inspected needs to be accessible. Two guided wave techniques have been developed which allow the sludge or blockages to be detected remotely without the need to access the specific location where the pipe is blocked, nor to open the pipe. The first technique measures the reflection of guided waves by sludge which can be used to accurately locate the blocked region; the second technique detects sludge by revealing the changes to the transmitted guided waves propagating in the blocked region or after it. The two techniques complement each other and their combination leads to a reliable sludge or blockage detection. Various types of realistic sludge have been considered in the study and the practical capabilities of the two techniques have been demonstrated.

• 대한방사선기술학회지:방사선기술과학
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• 제31권4호
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• pp.401-406
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• 2008

목적 : 종속조사면 병합 치료방법(FIF : Field In Field)을 이용한 유방절선조사 시 반대편 유방의 표면선량을 평가하고자 한다. 대상 및 방법 : FIF치료방법 이용 시 반대편 유방에 흡수되는 표면선량을 평가하고자 동일한 기하학적 조건과 처방선량을 기반으로 열린조사면(Open), 금속쐐기(MW : Metal Wedge), 동적쐐기(EDW : Enhanced Dynamic Wedge)를 이용한 조사방법과 비교하였다. 3차원 치료계획장치를 이용하여 선량분포 최적화를 수행하였으며 계산 결과의 정확도를 검증하기 위해 인체 팬톰과 모스펫 측정기를 사용하여 측정을 수행하였다. 동측 유방 입사면 가장자리로부터 반대편 유방 쪽으로 2, 4, 6, 8, 10cm 지점을 선정하여 각각 표면(0cm : 가피)과 0.5cm(진피) 깊이에서 선량을 측정하였으며, 0.5cm 깊이 선량측정을 위해서 0.5cm 볼루스를 사용하였다. 선량분포의 계산은 불균질 물질을 보정(modified Batho method)하여 0.25cm 격자 해상도로 수행하였다. 결과 : 치료계획장치에서 각 지점의 평균표면선량은 금속쐐기의 경우 표면 및 0.5cm 깊이에서 $19.6{\sim}36.9%$, $33.2{\sim}138.2%$ 증가했고, 동적쐐기는 $1.0{\sim}7.9%$, $1.6{\sim}37.4%$까지 증가하였다. FIF는 $-18.4{\sim}0.7%$, $-8.1{\sim}4.7%$까지 선량이 변화하였다. MOSFET을 이용하여 측정한 경우는 금속쐐기는 표면 및 0.5cm 깊이의 경우 $11.1{\sim}71%$, $22.9{\sim}161.2%$ 증가했고, 동적쐐기는 $4.1{\sim}15.5%$, $8.2{\sim}37.9%$ 선량이 증가했다. FIF는 표면에서 $-15.7{\sim}-4.9%$로 선량이 오히려 감소했으며, 0.5cm 깊이에서의 선량도 $-10.5{\sim}3.6%$로 나타났다. 치료계획장치의 계산값과 실측값을 비교한 결과, 유사한 경향을 보였으나 치료계획장치의 경우 피부선량이 실제측정값보다 다소 과소평가되고 있음을 알 수 있었다. 결론 : 본 실험을 통해 FIF치료방법의 경우 기존 치료방법(MW, EDW)에 비해 치료표적에 최적화 된 선량 분포를 만들어 내면서도 반대편 유방의 피부에 불필요한 산란선량을 최소화하는 치료방법임을 알 수 있었다.

• Clinics in Shoulder and Elbow
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• 제2권1호
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• pp.60-73
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• 1999

Purpose : The purpose of this study was to compare patients with anterior shoulder instability who were treated with an open Bankart procedure with those treated with an arthroscopic procedure, and to evaluate factors influencing the final outcomes and recurrence. Materials & Methods : One hundred seven shoulders underwent open Bankart repair, and fifty-one shoulders were treated arthroscopically. Average followup for open group was 34 months, and for arthroscopy group was 25 months. The Bankart Rating System by Rowe was used to evaluate the clinical outcome of the procedure. And, the patients were asked about any changes concerning their sports and professional activities. Results: According to Bankart Rating system by Rowe, open group had 97% fair to excellent results with 2 recurrent dislocation(1.8%) and 4 recurrent subluxation(3.6%), and arthroscopy group had 94% fair to excellent results with 3 recurrent dislocation(5.8%) and 4 recurrent subluxation(8%). In open group, 9 shoulders(8.4%) had the mild limitation of range of motion at the time of followup, and 2 shoulders(3.9%) in arthroscopy group. Age and gender do not seem to be a significant factor contributing to an increased re-recurrence rate. The incidence of re-recurrence seems to be affected by dominance, frequency, and patient's activity. The size of Bank art lesion might be also considered as a contributing factor. Conclusion: Either open or arthroscopic Bankart procedures are safe and effective methods with acceptable results if an adequate patient's selection, precise surgical technique and proper postoperative care are done. And arthroscopic surgery could be considered if the anterior instability is non-dominant, non-athlete, traumatic unidirectional and Bankart lesion has minimal erosion of the glenoid and it has thick and mobile labrum.

• 한국도서관정보학회지
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• 제36권4호
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• pp.255-284
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• 2005

본 연구에서는 오픈액세스(개방접근) 환경에서의 국내외 저작권관리시스템 사례연구를 토대로 현재 국내 개방접근환경의 기반 마련을 위해 개발 중인 dCollection 라이선스관리시스템을 분석하고 발전과제를 제시하였다. 연구를 위해 첫째, 개방접근의 장벽으로 작용하는 저작권과 라이선스 그리고 저작권관리(DRM)의 기본적인 개념과 기술적 요소를 살펴봄으로 개방형시스템들이 추구하는 이론과 기반 기술들이 어떻게 접목가능한지 이해를 높이고자 했다. 둘째, 개방접근 환경에서 저작권 보호를 위한 다양한 연구 중 해외 사례로 Creative Commons, ROMEO, Dspace시스템 분석과 국내 사례로 경북대학교와 서울대학교의 저작권관리시스템을 분석하였다. 마지막으로는 국내 개방접근환경에서 콘텐츠의 저작권보호와 유통활성화를 목적으로 개발 중인 dCollection 라이선스관리시스템 분석을 통해 발전 과제를 제시함으로 국내 상황을 직시하고 미래 발전 방향을 예측해 보고자 한다.

• 상하수도학회지
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• 제23권3호
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• pp.345-352
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• 2009

The purpose of inlet baffle is to distribute the flow uniformly over the entire cross-sectional area of the sedimentation basin. The goal when designing this baffle is to achieve some head loss while keeping the velocity gradients through the ports equal to the velocity gradient in the end of the flocculator, so as to not break up the flocs. Sedimentation tank performance is strongly influenced by hydrodynamic and physical effects such as inlet design. This study was conducted to evaluate the effect of open ratio of the inlet baffle on hydraulic behavior within a rectangular sedimentation basin using CFD simulation and ADV technique. In order to verify the CFD simulation, we measured the factual velocity at 18 points in the full-scale sedimentation basin at Y water treatment plant. Good agreement was obtained between the CFD predictions and the experimentally measured data. From the simulation results of the existing basin with 7.4 % open ratio, it was investigated that extreme decrease in velocity occurred in the middle of basin. Since then, flow features was unstable. The region which the velocity decrease rapidly moved forward to the flow direction in proportion to the increase of inflow velocity. Also, it was investigated that the flow characteristic of 6.0 % open ratio was significantly different from 7.4 % open ratio at the same configuration condition. These results are a clear indication that inflow momentum and open ratio are the parameters affecting the characteristics of hydraulic patterns. The influence of these parameters on the sedimentation performance requires further study.

• 한국인터넷방송통신학회논문지
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• 제12권1호
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• pp.57-63
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• 2012

TIP기술은 2차원 그림 또는 한 장의 사진으로부터 기하정보를 추출하여 3차원 입체 효과를 만들어 영상 내부를 내비게이션 할 수 있는 기술로써, 게임, 엔터테인먼트, 교육, 홍보 등 다양한 응용분야에서 활용 가능한 기술이다. 본 논문에서는 android platform상에서의 OpenGL ES Library를 이용하여 확장된 TIP기술 적용 및 구현 방법을 제안한다. 제안 방법은 전경객체의 추출이 어려운 상황을 감안하여 보다 사실적 장면 구성이 용이하도록 사용자의 선택에 의한 소실점을 이용하고, OpenGL ES Library 를 이용하여 3차원 배경 모델을 획득한 후 이미지를 텍스처 매핑하여 3차원 가상공간을 완성한 후 카메라의 시점변환을 통해 이미지 내부를 내비게이션이 가능하도록 한다. 실험영상은 android platform상의 device에서 촬영한 이미지를 사용하여 android 2.1 및 OpenGL ES 1.0기반으로 구축된 제안 기술로 android platform의 스마트 device에서 적은 비용과 시간으로 다양한 응용개발에 적용 가능하도록 구현하였다.

• 환경생물
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• 제36권4호
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• pp.507-516
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• 2018

벼재배 논에서 온실가스 측정을 위해 사용되는 closed 챔버법은 시 공간적으로 변동 폭이 큰 메탄 플럭스를 측정하는 데는 한계가 있다. 이러한 문제점을 해결하고자 메탄플럭스 측정에 있어 에디공분산을 기반으로 하는 open-path 방법과 closed 챔버법을 비교분석하였다. 벼 재배 기간 중 메탄 플럭스 변동은 두 방법 모두 비슷한 경향을 보였고 closed 챔버를 이용한 메탄 측정 시간대의 값은 open-path 측정에 의한 값과 고도로 유의한 상관을 보였다. 다만 총배출량에 있어서 두 측정 방법 간에 나타난 약 31%의 차이가 발생했는데 이는 closed 챔버법에 따른 과다 측정과 open-path에 의한 과소측정으로 생각해 볼 수 있다. 정확한 원인 분석을 위해서 향후에도 추가적인 연구가 필요할 것으로 판단된다.