• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.29.2-29.2
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• 2010

항법분야에 있어서 위성항법시스템의 다양한 오차를 제거한 정밀한 위치 정보를 이용하여 이동체에 활용하는 연구가 진행되고 있다. 실제 환경에서 이동체를 이용한 항법실험을 수행하기 전 실제 환경과 유사한 가상의 실시간 테스트베드를 구축하여 알고리즘 테스트 및 검증 실험을 수행하려 한다. 이를 위해 이동체의 운동을 시뮬레이션하는 운동궤적제어시스템과 실제의 항법신호를 시뮬레이션하는 GNSS 시뮬레이터 사이의 시각동기화는 실시간 시뮬레이션을 구현하기 위해 필수적으로 요구된다. 동기화 되지 않은 시각정보는 이동체 운동궤적제어시스템에 의해 생성된 실제의 궤적과 GNSS 시물레이터로부터 생성된 궤적사이의 오차를 유발하여 항법수신기의 부정확한 항법신호를 유발한다. 이 연구는 GNSS 시뮬레이터를 이용한 실시간 테스트베드의 구축에 있어 필요한 이동체 운동궤적의 시각동기화 기술 개발을 목표로 한다. GNSS 시뮬레이터는 Spirent 사의 GPS 시뮬레이터가 사용되었다. 이동체의 위치, 속도, 가속도와 같은 움직임을 나타내는 운동에 관한 명령은 적용되어야 하는 정확한 시각이 함께 전송되므로, 이는 그 시각 이전에 GPS 시뮬레이터에 도달해야 한다. 따라서 1초(1 Hz) 또는 0.1초(10 Hz) 사이에 원격제어시스템과 GPS 시뮬레이터사이의 시각 동기화를 구현하였다. 시뮬레이터와의 시각정보 동기화를 위해 Amplicon사의 PCI-215 타이머카드를 이용하였고, 그 결과, 이동체 운동궤적제어시스템과 시뮬레이터의 시각정보를 $10^{-3}$ 내의 위치오차를 가지는 정밀도로 동기화됨을 확인할 수 있었다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제5권2호
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• pp.176-184
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• 1999

지금까지의 소프트웨어 기반 분산 공유 메모리(이하 DSM이라 칭함)시스템은 유닉스 워크스테이션 클러스터를 목표로 하는 것이 대부분이었다. 그러나 현재 Windows-NT 는 서버급 시스템과 PC 모두를 위한 운영체제로서 유닉스와 더불어 널리 사용되고 있는 실정이다. 본 논문에서는 Windows-NT 워크스테이션 클러스터 환경을 위한 DSM 시스템을 구현하고, 구현된 DSM 시스템의 성능 평가 결과를 제시한다. 구현된 DSM 시스템은 Win32 API와 표준 실행-시간 라이브러리를 이용해 구현되었기 때문에 모든 Windows-NT 워크스테이션에서 실행 가능하며 , 프로그래머는 몇 라인의 코드 추가만으로 DSM 시스템 상에서 수행되는 병렬 응용 프로그램을 작성할 수 있다. 워크스테이션 간의 상호연결망으로 범용성을 위해 이더넷 LAN을 지원하였고, 아울러 성능 향상을 위해 기가비트 SAN(System Area Network)도 지원하였다. 기가비트 SAN을 위한 하드웨어로는 Dolphin 사의 PCI-SCI 타입 제품인 Clustar를 사용하였다. 우리는 성능 평가를 통해, 구현된 DSM 시스템이 정확히 동작함은 물론 확장성이 뛰어나다는 것을 확인하였다. 특히 , 기가비트 SAN을 사용할 경우 일부 병렬 벤치 마크 프로그램에서는 노드 수 증가에 따라 성능이 거의 선형적으로 향상된다는 것을 알 수 있었다. 본 논문이 기여하는 바는 Windows-NT 기반 소프트웨어 DSM 시스템의 원천 기술을 확보함으로써 향후 Windows-NT 워크스테이션 클러스터 환경에서의 분산 및 병렬 처리 연구에 도움을 줄 수 있다는 점이다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.936-939
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• 2003

Potential and capabilities of GIS in planning and decision-making is widely known as an experimental tool, but its existence in real-world application is yet to realize. GIS originated in the field of cartography and even at today it is mainly used as a tool for map production. Number of reasons could bring forward for this shortcoming. Limited real-world applications could be a significant one among them. This paper describe an attempt to use GIS technology in Lao PDR where a study team was involved in formulating a Master Plan for national healthcare system. A database was created for the whole country with spatial and descriptive data gathered from various sources. Attempt was made to demonstrate the potential of GIS by using the database for identifying healthcare status, distribution of resources, recognizing deprived areas and locating areas for future investments based on accessibility and social status. The approach justified the investment on a GIS system and introducing the system in the planning sector from grass-root level to central level.

• 한국도로학회논문집
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• 제16권1호
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• pp.1-10
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• 2014

PURPOSES : This study aimed to evaluate the long-term performance of bonded concrete overlay in Korean Highway, and factors influencing the performances. METHODS : The evaluation for long-term performance of bonded concrete overlay is investigated based on the following study : i) The pavement distress of number of bonded concrete overlay sections in Korean highway are collected through field measurement, and PCI for each section is calculated. ii) Performance of LTPP data of bonded concrete overlay sections in U.S.A is analysed. And it is compared with bonded concrete overlay of Korean highway. iii) An analysis of the factors influencing to long-term performance of bonded concrete overlay is investigated. RESULTS : Performance analysis was confirmed that the overlay thickness was affecting significantly on the Bonded Concrete Overlay life. The comparison of LTPP data(U.S.A) and field measurement data(Korean) was showed. CONCLUSIONS : It was showed that the performance of Korean bonded concrete overlay is relatively lower than that of the bonded concrete overlay in U.S.A. The cause of lower performance can be explained by the lack of overlay thickness.

• The Journal of Korean Physical Therapy
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• 제26권6호
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• pp.411-417
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• 2014

Purpose: This study attempts to find the effects of water-based exercise performed on stroke patients in their physiological cost index and static and dynamic balance. Methods: The subjects were 30 stroke patients, who were randomly divided a water-based exercise group and a land-based exercise group, each with 15 patients. Both exercises ware performed 3 day per week, for 40 minutes a day, for a period of eight weeks. Results: The Water-based exercise group showed a decreased physiological cost index compared to the land-based exercise group, with the physiological cost index of the water-based exercise group decreasing, while the land-based exercise group, showing a significant decrease. Water-based exercise increased static and dynamic balance capacity better than land-based group, showing a significant difference and better efficiency of water-based exercise when compared to land-based exercise. Conclusion: From the result of the study, we found that water-based exercise is more effective in improving PCI and static and dynamic balance capacity. Through this study, training in water-based stroke patients could use cardiovascular endurance and buoyancy and the vortex, as an effective treatment that can enhance the growth and voluntary participation in the range of the patient's own movement the thought is, in consideration of the changes in the physiological cost index due to the difference in the ground and water, and should establish a training program that matches the purpose.

• 대한원격탐사학회지
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• 제16권4호
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• pp.339-345
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• 2000

KOMPSAT-1 was launched on 21 December, 1999 and the main mission of the satellite is the cartography to provide the imagery from a remote earth view for the production of maps of Korean territory. For this purpose, the satellite has capability to tilt the spacecraft utmost $\pm$45 degrees to acquire stereo satellite imagery in different paths. This study aims to estimate the three dimensional positioning accuracy of stereo satellite imagery from EOC(electro-optical camera), a payload of KOMPSAT-1 satellite. For this purpose, the ground control points and check points were obtained by GPS surveying. The sensor modeling and the adjustment was performed by PCI software installed in KARI (Korea Aerospace Research Institute), which contained mathematical analysis module for KOMPSAT-1 EOC. The study areas were Taejon and Nonsan, placed in the middle part of Korea. As a result of this study, we found that the RMSE(root mean square error) value of three dimensional positioning KOMPST-1 stereo imagery can be less than 1 pixel (6.6 m) if we can use about 10 GCPs(ground control points). Then, a standarrd of FGDC (Federal Geographic Data Committee) of USA was applied to the result to estimate the three dimensional positioning accuracy of KOMPSAT-1 stereo imagery.

• 대한원격탐사학회지
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• 제38권1호
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• pp.127-137
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• 2022

Urban Heat Island (UHI) effect has been widely studied as a global concern of the 21st century. Heat generation from urban built-up structures and anthropogenic heat sources are the main factors to create UHIs. Unfortunately, both factors are expanding rapidly in Lahore and accelerating UHI effects. The effects of UHI are expanding with the expansion of impermeable surfaces towards urban green areas. Therefore, this study was arranged to analyze the role of urban cooling intensity in reducing urban heat island effects. For this purpose, 15 parks were selected to analyze their effects on the land surface temperature (LST) of Lahore. The study obtained two images of Landsat-8 based on seasons: the first of June-2018 for summer and the second of November-2018 for winter. The LST of the study area was calculated using the radiative transfer equation (RTE) method. The results show that the theme parks have the largest cooling effect while the linear parks have the lowest. The mean park LST and PCI of the samples are also positively correlated with the fractional vegetation cover (FVC) and normalized difference water index (NDWI). So, it is concluded that urban parks play a positive role in reducing and mitigating LST and UHI effects. Therefore, it is suggested that the increase of vegetation cover should be used to develop impervious surfaces and sustainable landscape planning.

• Structural Monitoring and Maintenance
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• 제9권4호
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• pp.337-357
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• 2022

The objective of this study is to present a data-driven machine learning (ML) framework for predicting ultimate shear strength and failure modes of reinforced concrete ledge beams. Experimental tests were collected on these beams with different loading, geometric and material properties. The database was analyzed using different ML algorithms including decision trees, discriminant analysis, support vector machine, logistic regression, nearest neighbors, naïve bayes, ensemble and artificial neural networks to identify the governing and critical parameters of reinforced concrete ledge beams. The results showed that ML framework can effectively identify the failure mode of these beams either web shear failure, flexural failure or ledge failure. ML framework can also derive equations for predicting the ultimate shear strength for each failure mode. A comparison of the ultimate shear strength of ledge failure was conducted between the experimental results and the results from the proposed equations and the design equations used by international codes. These comparisons indicated that the proposed ML equations predict the ultimate shear strength of reinforced concrete ledge beams better than the design equations of AASHTO LRFD-2020 or PCI-2020.

• Communications for Statistical Applications and Methods
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• 제29권2호
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• pp.177-191
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• 2022

This paper addresses the use of machine learning methods for causal estimation of treatment effects from observational data. Even though conducting randomized experimental trials is a gold standard to reveal potential causal relationships, observational study is another rich source for investigation of exposure effects, for example, in the research of comparative effectiveness and safety of treatments, where the causal effect can be identified if covariates contain all confounding variables. In this context, statistical regression models for the expected outcome and the probability of treatment are often imposed, which can be combined in a clever way to yield more efficient and robust causal estimators. Recently, targeted maximum likelihood estimation and causal random forest is proposed and extensively studied for the use of data-adaptive regression in estimation of causal inference parameters. Machine learning methods are a natural choice in these settings to improve the quality of the final estimate of the treatment effect. We explore how we can adapt the design and training of several machine learning algorithms for causal inference and study their finite-sample performance through simulation experiments under various scenarios. Application to the percutaneous coronary intervention (PCI) data shows that these adaptations can improve simple linear regression-based methods.

• 대한한방내과학회지
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• 제45권3호
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• pp.478-487
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• 2024

Objectives: This case report describes good clinical progress in a patient with symptoms related to angina pectoris treated with a herbal medication. Methods: The 66-year-old male patient hospitalized in Chonnam National University Hospital (CNUH) in May 2020 for symptoms of dyspnea and chest pain was diagnosed with angina pectoris, medicated, underwent PCI in August 2020, and continued to take the medicine prescribed at CNUH during hospitalization. Korean medical treatments, including herbal medicines (Saengmaeg-san-hap-Bojungikgi-tang-gami, Yeonggyechulgam-tang), acupuncture, and cupping therapy were administered for 22 days. Symptom severity was assessed with a daily visual analog scale (VAS) for dyspnea and chest pain and standard deviation of NN (SDNN) score of heart rate variability. Results: Post-treatment, severity of dyspnea, chest pain, and fatigue reduced from VAS 7 to VAS 2, VAS 6 to VAS 1, and VAS 7 to VAS 1, respectively. The SDNN score improved from 16.474 ms to 23.270 ms. There were no side effects from Korean medicine treatment. Conclusion: Traditional Korean treatment could effectively treat symptoms related to angina pectoris.