• 대한물리의학회지
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• 제18권2호
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• pp.103-114
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• 2023

PURPOSE: This study compared the effects of computer-based and virtual reality-based cognitive rehabilitation programs on the cognitive function, upper limb function, activities of daily living, and their impact on the prefrontal cortex in convalescent stroke patients. METHODS: Ten recovering stroke patients were assessed for their cognitive function, upper limb function, and daily living activities using the Neurobehavioral Cognitive Status Examination, the Korean version of the Fugl-Meyer Assessment, and the Korean version of the Modified Barthel Index. The prefrontal cortex activity was measured with functional Near Infrared Spectroscopy. The virtual reality-based cognitive rehabilitation group utilized a program of daily living activities delivered via a laptop and Oculus Rift. The computer-based cognitive rehabilitation group performed various cognitive tasks on an all-in-one PC. Both groups underwent cognitive rehabilitation training for 30 minutes per day, three times a week, for six weeks, with identical conventional rehabilitation therapies in the hospital. RESULTS: Both programs positively impacted the cognitive and physical functions. On the other hand, the virtual reality-based cognitive rehabilitation program had a larger influence on improving the cognitive and physical functions of convalescing stroke patients. CONCLUSION: The virtual reality program suggests its potential to enhance cognitive and physical functions in convalescent stroke patients through increased engagement, focus, real-time feedback, and game elements, making it a promising rehabilitation approach.

• 한국해양공학회지
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• 제38권2호
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• pp.64-73
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• 2024

Oil spills pose significant threats to marine ecosystems, human health, socioeconomic aspects, and coastal communities. Accurate real-time predictions of oil slick transport along coastlines are paramount for quick preparedness and response efforts. This study used an open-source OpenOil numerical model to simulate the fate and trajectories of oil slicks released during the 2007 Hebei Spirit accident along the Korean coasts. Six combinations of input parameters, derived from a five-day met-ocean dataset incorporating various hydrodynamic, meteorological, and wave models, were investigated to determine the input variables that lead to the most reasonable results. The predictive performance of each combination was evaluated quantitatively by comparing the dimensions and matching rates between the simulated and observed oil slicks extracted from synthetic aperture radar (SAR) data on the ocean surface. The results show that the combination incorporating the Hybrid Coordinate Ocean Model (HYCOM) for hydrodynamic parameters exhibited more substantial agreement with the observed spill areas than Copernicus Marine Environment Monitoring Service (CMEMS), yielding up to 88% and 53% similarity, respectively, during a more than four-day oil transportation near Taean coasts. This study underscores the importance of integrating high-resolution met-ocean models into oil spill modeling efforts to enhance the predictive accuracy regarding oil spill dynamics and weathering processes.

• 대한전자공학회논문지TC
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• 제44권3호
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• pp.68-77
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• 2007

본 논문에서는 E-PON 기반 TPS (Triple Play Service)에 대한 연구와 더불어 E-PON의 단점인 양방향 QoS 기능 개발에 관한 것이다. E-PON 시스템은 TPS에 적합한 구성을 가지고 있으나, upstream 지연이 상대적으로 큰 특성을 가지고 있으므로, 양방향 실시간 트래픽 전달을 위한 QoS 제어 기능이 지원되어야만 실제 환경에서 TPS를 효과적으로 지원할 수 있다. 따라서 본 논문에서는 TPS를 위한 다양한 품질 요구사항을 제시하고 이를 기반으로 실제 환경에서 종단간 각 요소들의 QoS 특성에 따른 품질 특성을 검증할 수 있는 TPS 플랫폼을 개발하였다. 이 결과는 향후 일반화될 TPS에 품질 개선을 위한 기반으로 활용될 것이며, 서비스 사업자 입장에서는 품질 기준을 수립하는데 기준으로 활용될 수 있으며, 신규 시스템 개발 시 개발 방향에 지침으로 활용될 수 있을 것이다.

• 융합보안논문지
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• 제12권1호
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• pp.35-42
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• 2012

데이터 트래픽의 증가와 대용량 실시간 서비스와 관련된 요구사항들의 증가는 음성이나 전용선 서비스를 주된 목적으로 하는 기존의 시간분할 다중화(TDM: Time Division Multiplexing) 기반 네트워크에서 좀 더 유연하고 동적인 구성이 가능한 광 네트워크로의 전환을 요구하고 있다. 이러한 광 네트워크는 데이터, 비디오, 그리고 음성을 전달할 수 있는 다수의 채널을 제공하는 핵심 인프라가 되었다. 이를 위해 차세대 패킷광 통합망은 네트워크 이상이 발생하여도 용인할 수 있는 수준의 서비스를 지속적으로 제공할 수 있어야 한다. 또한 신속하고 최적화된 복구(restoration) 정책은 GMPLS(Generalized Multi-Protocol Label Switching) 기반 제어평면을 사용으로 하는 차세대 패킷광 통합망의 가장 중요한 요구사항이 되었다. 본 논문은 GMPLS 기반 다계층 패킷광 통합망에서 신속하고 일원화된 복구를 지원하기 위한 계층적인 다계층 복구방식을 살펴보고 이를 지원하기 위한 구현방식을 제안하는 것을 목적으로 하고 있다. 또한 본 논문에서는 기존의 신호 및 라우팅 프로토콜을 수정하지 않고 제안한 방식을 구현할 수 있는 방안의 제안을 목적으로 하고 있다.

• 한국터널지하공간학회 논문집
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• 제18권6호
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• pp.545-556
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• 2016

운영 중 해저 터널의 안정성 평가에 다양한 계측 정보를 사용해서 역해석하면, 효율적인 오차율 이내의 결과를 획득할 수 있다. 선행 연구에서 검증된 차분진화 알고리즘 기반의 역해석 수행 시 FLAC3D 등 범용 지반해석 프로그램을 사용했지만, 상대적으로 해석시간이 오래 걸리고, 제어가 어려운 단점이 있다. 이러한 이유로, 상대적으로 해석시간이 짧게 소요되는 beam-spring 모델기반의 FEM solver를 Python 언어로 개발하여, 기구축된 차분진화 알고리즘과 결합하였다. 계측 데이터로부터 실시간에 가깝게 운영 중 터널의 안정성 평가가 가능할 것으로 판단되며, 우선 솔버 개발에 용이한 종단방향 터널에 대해서 프로그램을 개발하였다.

• Journal of Astronomy and Space Sciences
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• 제36권1호
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• pp.35-43
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• 2019

The Optical Wide-field patroL-Network (OWL-Net) is a global optical network for Space Situational Awareness in Korea. The primary operational goal of the OWL-Net is to track Low Earth Orbit (LEO) satellites operated by Korea and to monitor the Geostationary Earth Orbit (GEO) region near the Korean peninsula. To obtain dense measurements on LEO tracking, the chopper system was adopted in the OWL-Net's back-end system. Dozens of angle-only measurements can be obtained for a single shot with the observation mode for LEO tracking. In previous work, the reduction process of the LEO tracking data was presented, along with the mechanical specification of the back-end system of the OWL-Net. In this research, we describe an integrity assessment method of time-position matching and verification of results from real observations of LEO satellites. The change rate of the angle of each streak in the shot was checked to assess the results of the matching process. The time error due to the chopper rotation motion was corrected after re-matching of time and position. The corrected measurements were compared with the simulated observation data, which were taken from the Consolidated Prediction File from the International Laser Ranging Service. The comparison results are presented in the In-track and Cross-track frame.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.279-284
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• 2004

Red tide(harmful algae) in the Korean Coastal Waters has a given a great damage to the fishery every year. However, the aim of our study understands the influence of meteorological factors (air and water tempaerature, precipitation, sunshine, solar radiation, winds) relating to the mechanism of red tide occurrence and monitors red tide by satellite remote sensing, and analyzes the potential area for red tide occurrence by GIS. The meteorological factors have directly influenced on red tide formation. Thus, We want to predict and apply to red tide formation from statistical analyses on the relationships between red tide formation and meteorological factors. In future, it should be realized the near real time monitoring for red tide by the development of remote sensing technique and the construction of integrated model by the red tide information management system (the data base of red tide - meteorological informations).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1077-1083
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• 2011

Turnout is one of railroad track components. The turnout is used to change train routes to near other sections when keeping the train speed. There are many accidents in the section including the turnout. The number of accidents and errors is 363 for ten years in the section including the turnout and annual average is 36.3. To ensure safety of the turnout, it is necessary to install monitoring systems. By using the monitoring systems, it is able to accumulate related information, develop maintenance and take a step for accidents in advance. Hence, The number of accidents and errors is decreased in the section including the turnout. So, when new turnout is installed, it is needed to use monitoring systems. Therefore, combined turnout management system is needed in Korea. It is possible to perform efficient maintenance because real-time monitoring system by using sensors and data-base management system. In this paper, accidents in the section including domestic turnout are analyzed and foreign combined turnout management system is presented. Hence, articles for installing the combined turnout management system in Korea are proposed.

• 천문학회보
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• 제40권1호
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• pp.64.3-64.3
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• 2015

We have developed a set of daily solar flare peak flux forecast models for strong flares using multiple linear regression and artificial neural network methods. We consider input parameters as solar activity data from January 1996 to December 2013 such as sunspot area, X-ray flare peak flux and weighted total flux of previous day, and mean flare rates of McIntosh sunspot group (Zpc) and Mount Wilson magnetic classification. For a training data set, we use the same number of 61 events for each C-, M-, and X-class from Jan. 1996 to Dec. 2004, while other previous models use all flares. For a testing data set, we use all flares from Jan. 2005 to Nov. 2013. The best three parameters related to the observed flare peak flux are weighted total flare flux of previous day (r = 0.51), X-ray flare peak flux (r = 0.48), and Mount Wilson magnetic classification (r = 0.47). A comparison between our neural network models and the previous models based on Heidke Skill Score (HSS) shows that our model for X-class flare is much better than the models and that for M-class flares is similar to them. Since all input parameters for our models are easily available, the models can be operated steadily and automatically in near-real time for space weather service.

• 천문학논총
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• 제15권spc2호
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• pp.15-20
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• 2000

The geomagnetic measurements on the Korean Territory began in 1918 in the Incheon (Zinsen in Japanese pronunciation) Observatory of which the annual means of total magnetic field intensity, declination, and inclination still remain for 1918-1944. From 1970s, the National Geography Institute (NGI) and the Radio Research Laboratory (RRL) have tried independently to measure the geomagnetic field continuously. The RRL as the result of such efforts has installed 3 geomagnetic observatories, the first in Icheon and the second in Yongin in 1996, and the third in Jeju in 1997. From 1992, the Korea Institute of Geology, Mining and Materials (KIGAM) has tried also to measure the geomagnetism and as the result they have installed 2 geomagnetic observatories, one in Daejeon in 1998 and the other in Gyeongju in 2000. Nowadays, the RRL and the KIGAM collect the measured data into their own main computers by telecommunication in real time. The two institutions will cooperate in near future to link the two geomagnetic data bases so that the whole set of geomagnetic data measured on Korean Territory could be provided to the end users in Korea.