• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.89-98
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• 2009

As data stream is entered into system continuously and the memory space is limited, the data exceeding the memory size cannot be processed. In order to solve the problem, load shedding methods which drop a part of data to prevent exceeding the storage space have been researched. Generally, a traditional load shedding method uses random sampling with optimized rate according to data deviation. The method samples data not to distinguish those used in spatial query because the method uses only a random sampling with optimized rate according to data deviation. Therefore, the accuracy of query was reduced in u-GIS environment including spatial query. In this paper, we researched a new load shedding method improving accuracy of the query in u-GIS environment which runs spatial query and aspatial query simultaneously. The method uses a new sampling method that samples data having low probability used in query. Therefore proposed method improves spatial query accuracy and query processing speed as applying spatial filtering operation to sampling operator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7A
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• pp.706-714
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• 2010

In wireless sensor networks, real-time data delivery schemes typically achieve a desired delivery speed by performing one-hop lookahead. Recently, to reduce the deadline miss ratio against the desired delivery speed, a study has proposed a real-time routing protocol based on proactively performing two-hop lookahead. However, the study might cause heavy message exchange overhead and high computing complexity to carry out obtainment of two-hop neighborhood speed information in the entire sensor nodes whether data are delivered or not. Moreover, although multi-hop lookahead provides the least deadline miss ratio, due to the restriction from the overhead and the complexity, the recent study merely adopts the two-hop lookahead manner. In this paper, we propose a novel real-time routing protocol that adopts on-demand neighborhood multi-hop information obtainments only around data forwarding paths. Simulation results prove that the proposed routing protocol offers better performances with respect to deadline miss ratio, total communication costs, energy efficiency, and network lifetime.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.362-370
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• 2019

This study was conducted to investigate effects of 12 weeks of combined exercise training with blood flow restriction (BFR) on body composition (weight, %body fat, lean body mass, body mass index (BMI)) and cardiovascular responses (brachial-ankle pulse wave velocity (ba PWV) and ankle-brachial index (ABI)) in elderly women. Participants (N = 43, Females) were randomly assigned into a combined exercise with BFR (n = 14, BFR), only combined exercise (n =14, EX) or non-exercise control group (n = 15, CON). Two-way repeated measures ANOVA with contrast testing was utilized for data analysis. Alpha was set at p < 0.05. Body composition (weight, %body fat, BMI) in BFR was significantly changed, and %body fat in EX was significantly decreased, but there was no change in the CON. In addition, the right and left ba PWV values in the BFR were significantly decreased, while only the left side ba PWV in EX was significantly decreased and there was no change in the CON. Moreover, the % change and effect size of most variables in the BFR were higher than the EX. Taken together, the results indicate that even though BFR and EX groups performed the same combined exercise training, BFR had additional stimulations of the sympathetic nerve system due to blood flow restriction. Thus, BFR training is more beneficial and has greater effects on body composition and cardiovascular responses in elderly females.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.473-474
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• 2015

유도탄 구동장치용 제어기는 제한된 공간 내에서 최적의 성능 및 신뢰성을 구현하도록 구성되어야 한다. 유도탄 구동장치에 요구되는 강건제어를 구현하기 위하여 위치 및 속도 제어를 수행하였으며, 속도값은 센서 없이 HGO(High Gain Observer) 기법을 이용하여 추정하였다. 시험 및 검증을 위해 프로토타입 제어기 및 구동기를 활용하였으며, Matlab/Simulink를 통한 시뮬레이션 및 실제 시험결과가 일치함을 확인하고, 이러한 구동 제어기 개발 기법의 적절성을 제시하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.97-106
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• 2005

Since traffic engineering in 1950's, 'speed control technology' has experienced tremendous growth and developed constantly. However, speeding remains a major safety concern on many roadways. Many crashes is believed to be the result of driving too fast. Recently the speed reduction device, the speed monitoring display with ITS technologies have developed and introduced in many countries including our nation, Korea. Therefore This paper describes an evaluation of the use of a speed monitoring display, speed limit sign, and school zone sign. Two conditions were evaluated; without installation of Speed Monitoring Display, in Operation of Speed Monitoring Display.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.10
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• pp.962-974
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• 2010

Recently, the convergence of information technology with bio-technology, nano-technology or other technologies has been creating a new paradigm. In a field of transportation, the intelligent transport systems which is a convergence of intelligent technologies and transportation systems have been studied. The Variable Speed Limit(VSL), is one of ITS technologies, is thought to improve safety and efficiency of transportation while controlling speed limit based on road conditions. Legacy studies have considered only one station for VSL algorithm. However, it is not appropriate for an urban freeway installed with many stations. In this paper, new algorithm is proposed to not only enhance effectiveness of VSL based on cooperation of stations but also reflect road conditions within 30 seconds. The proposed algorithm consists of 4 steps: the first is a "searching bottleneck station" step, the second is a "calculating a size of congestion" step, the third is a "calculating the number of controlled stations" step, the final is a "calculating VSL" step. This algorithm guarantees improved safety and minimum additional travel time. The travel time should be considered because drivers would against the VSL algorithm when the proposed algorithm occurs additional travel time. In our experiments, microscopic traffic simulator VISSIM is selected to perform a modeling work. The results show that proposed algorithm provides the improved safety and minimum increase of travel time.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.703-707
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• 2008

This paper proposes a method of design and implementation a simulation system in which humans can plan their evacuation paths in a high-rise building considering damages from high temperature and smoke in case of fire. Humans in evacuation search the nearest exit and follow a path to the exit. When humans are evacuating toward an exit, they are going to move with their highest speeds. However, many environmental factors prohibit their fast movements. In this paper, we calculate the evacuation speed of each human considering temperature damage and smoke damage. We restrict the number of humans that can be evacuated per second according to the actual size of the exit door. Experimental results showed that the evacuation speed is affected by the temperature condition and the smoke density.

• Journal of the Society of Disaster Information
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• v.7 no.1
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• pp.1-11
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• 2011

Plans of underground roads have been established, and the possibilities of underground road constructions have been growing in Korea. However, the study on characteristics of underground roads, the enactment of law, and the establishment of design criteria haven't been conducted so far, if any. Based on these backgrounds, the paper presents the basic direction on the construction method of underground roads. It also investigates the needs and characteristics of underground roads and reviews domestic and foreign examples. Major results by implementing the research are as follows: 1) when selecting the route of underground roads, the use of underground space, technical aspects, and traffic systems should be comprehensively considered; 2) the design speed of underground roads will be 10km/h above the speed limit to secure safety; 3) disaster prevention facilities should be planned to connect high traffic management system for coping with unexpected situations. Although this study has a limitation that hasn't reflected the driver's characteristics on new spaces such as underground roads, it has some significance that it suggests the major reviewing issues on the construction of underground roads, and presents the direction through the previous study.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.33-36
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• 2012

변이 탐색 범위는 스테레오 정합을 위한 변이 추정 알고리즘의 성능에 가장 큰 영향을 줄 수 있는 변수 중 하나이다. 일반적으로 이러한 변이 탐색 범위는 영상 전체의 최소 변이 값과 최대 변이 값의 범위로 정의된 전역적인 탐색 범위를 사용하게 된다. 이러한 전역적인 탐색 범위는 픽셀에 따라서 불필요한 범위에까지 탐색하게 하며, 이는 변이 추정의 성능적, 속도적 측면에서 좋지 않은 영향을 미치게 된다. 본 논문에서는 픽셀에 따라 변이 탐색 범위를 제한시키는 방법을 제안한다. 낮은 계산 복잡도를 갖는 간단한 변이 추정 알고리즘을 통해 먼저 변이 지도를 생성하여 각 픽셀 당 윈도우를 대응하여 변이 히스토그램을 만든다. 변이 히스토그램에 적응적인 임계 값을 적용하여 픽셀당 변이 후보군을 결정한다. 전역적인 변이 탐색 범위와 제안하는 방법으로 제한된 변이 탐색 범위를 각각 동일한 변이 추정 알고리즘에 적용해 보는 실험을 통해 제안하는 방법의 성능을 분석하였다. 실험 결과로부터 제안하는 방식은 변이 추정 알고리즘의 정확도 측면의 성능을 향상시켰고, 알고리즘의 속도를 평균 5배 이상 향상시켜주는 결과를 보여주었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.340-343
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• 2009

u-GIS 환경에서 GeoSensor로부터 수집되는 시공간 데이터는 데이터 스트림의 특징을 포함한다. 데이터 스트림은 다양한 입력 속도로 끊임없이 입력되고, 데이터의 크기 또한 가변적이다. 이런 이유로 한정적인 메모리와 처리능력의 시스템은 과부하 현상이 발생한다. 이를 해결하기 위해 초과되는 데이터를 버려 메모리 초과를 방지하는 기법들이 연구되고 있다. 공간질의는 공간과 위치 값을 기반으로 이루어지는 연산으로 공간질의 정확도는 공간과 위치 정보를 통해 보장된다. 그러나 기존 기법인 랜덤부하제한 기법과 의미적부하제한 기법은 공간질의가 요구하는 공간과 위치 값에 대해 고려하지 않고 삭제하기 때문에 공간질의에 대한 정확도가 감소하는 문제를 갖는다. 본 논문에서는 공간의 이용도를 이용하여 차등적 비율을 적용한 부하제한 기법은 연구하였다. 이 기법은 등록된 공간질의의 영역 겹침 정도에 따라 중요 레벨을 증가시키고, 이를 토대로 시공간 데이터의 중요도를 파악하여 중요도마다 주어진 비율에 의하여 차등적으로 삭제한다. 결과적으로 기존 기법보다 다소 높은 Drop rate를 통해 질의 처리 속도를 빠르게 회복시켰으며, 중요 데이터를 최대한 유지하여 Error rate를 감소시켰다.