• 산업경영시스템학회지
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• 제38권4호
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• pp.11-21
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• 2015

In order to achieve success in ground operations, searching for moving targets is one of critical factors. Usually, the system of searching for adversary ground moving targets has complex properties which includes target's moving characteristics, camouflage level, terrain, weather, available search time window, distance between target and searcher, moving speed, target's tactics, etc. The purpose of this paper is to present a practical quantitative method for effectively searching for infiltrated moving targets considering aforementioned complex properties. Based upon search theories, this paper consists of two parts. One is infiltration route analysis, through terrain and mobility analysis. The other is building dynamic probability maps through Monte Carlo simulation to determine the prioritized searching area for moving targets. This study primarily considers ground moving targets' moving pattern. These move by foot and because terrain has a great effect on the target's movement, they generally travel along a constrained path. With the ideas based on the terrain's effect, this study deliberately performed terrain and mobility analysis and built a constrained path. In addition, dynamic probability maps taking terrain condition and a target's moving speed into consideration is proposed. This analysis is considerably distinct from other existing studies using supposed transition probability for searching moving targets. A case study is performed to validate the effectiveness and usefulness of our methodology. Also, this study suggests that the proposed approach can be used for searching for infiltrated ground moving target within critical time window. The proposed method could be used not only to assist a searcher's mission planning, but also to support the tactical commander's timely decision making ability and ensure the operations' success.

• 대한건축학회논문집:계획계
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• 제36권5호
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• pp.59-70
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• 2020

The purpose of this study is to derive the environmental factors affecting child loss through correlation analysis between child loss and pedestrian density. The status of lost children was identified through the lost child records and interviews in large parks. In addition, the behavior survey was conducted by photographing the entire outdoor of each park, and visitors was marked on the behavioral maps. Also, the pedestrian density was analyzed by GIS as 100㎡ and 1㎡ grid. As a result, child loss was related to the pedestrian density rather than the number of visitors or the area. Especially, 'Dynamic pedestrian density' and 'Ratio of pedestrian in high density to area' was related to child loss. In other words, the more dynamic behaviors such as play and movement appear, and the more the local area of high density, the higher the probability of child loss. In addition, environmental factors that induce such high density include bottlenecks, overlap of circulation due to multi-functionality of space, concentration of rides, and concentration of guardians due to visual obstacles.

• Journal of Communications and Networks
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• 제8권1호
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• pp.93-105
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• 2006

The domination of the Internet by TCP-based services has spawned many efforts to provide high network utilization with low loss and delay in a simple and scalable manner. Active queue management (AQM) algorithms attempt to achieve these goals by regulating queues at bottleneck links to provide useful feedback to TCP sources. While many AQM algorithms have been proposed, most suffer from instability, require careful configuration of nonintuitive control parameters, or are not practical because of slow response to dynamic traffic changes. In this paper, we propose a new AQM algorithm, hybrid random early detection (HRED), that combines the more effective elements of recent algorithms with a random early detection (RED) core. HRED maps instantaneous queue length to a drop probability, automatically adjusting the slope and intercept of the mapping function to account for changes in traffic load and to keep queue length within the desired operating range. We demonstrate that straightforward selection of HRED parameters results in stable operation under steady load and rapid adaptation to changes in load. Simulation and implementation tests confirm this stability, and indicate that overall performances of HRED are substantially better than those of earlier AQM algorithms. Finally, HRED control parameters provide several intuitive approaches to trading between required memory, queue stability, and response time.

• 한국융합학회논문지
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• 제10권11호
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• pp.303-308
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• 2019

본 연구에서는 지진하중에 대한 구조물의 동적해석 과정에서 실제적이고 신뢰성 있는 확률 통계적 지진응답 결과를 얻기 위해 로그정규분포 기반 지진응답 도출 방안을 제안하였다. 이를 위해 미국지질조사국(USGS)에서 제시한 로스앤젤레스 지역 지진재해도에 따라 50년 동안의 발생 초과확률이 2%, 5%, 10%인 30개 지진데이터들을 활용하였다. 해석 대상으로서는 기본적인 동적거동 파악을 위해 단자유도계를 선정, 이의 고유진동주기 별 응답을 나타내는 응답 스팩트럼을 도식하여 응답 추이를 분석하였다. 최종적으로 도출된 로그정규분포 기반 응답의 경우 기존의 정규분포 기반 응답에 비해 모든 고유주기 영역에서 상대적으로 낮은 응답을 보였다. 제안된 로그정규분포 기반의 지진응답 평가는 성능기반내진설계를 위한 경제적 평가 방식으로서의 대안이 될 수 있을 것으로 기대된다.

• Geomechanics and Engineering
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• 제16권4호
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• pp.435-448
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• 2018

In order to make reliable earthquake-resistant design of civil engineering structures, one of the most important considerations in a region with high seismicity is to pay attention to the local soil condition of regions. It is aimed in the current study at specifying dynamic soil characteristics of Kirikkale city center conducting the 1-D equivalent linear and non-linear site response analyses. Due to high vulnerability and seismicity of the city center of Kirikkale surrounded by active many faults, such as the North Anatolian Fault (NAF), the city of Kirikkale is classified as highly earthquake-prone city. The first effort to determine critical site response parameter is to perform the seismic hazard analyses of the region through the earthquake record catalogues. The moment magnitude of the city center is obtained as $M_w=7.0$ according to the recorded probability of exceedance of 10% in the last 50 years. Using the data from site tests, the 1-D equivalent linear (EL) and nonlinear site response analyses (NL) are performed with respect to the shear modulus reduction and damping ratio models proposed in literature. The important engineering parameters of the amplification ratio, predominant site period, peak ground acceleration (PGA) and spectral acceleration values are predicted. Except for the periods between the period of T=0.2-1.0 s, the results from the NL are obtained to be similar to the EL results. Lower spectral acceleration values are estimated in the locations of the city where the higher amplification ratio is attained or vice-versa. Construction of high-rise buildings with modal periods higher than T=1.0 s are obtained to be suitable for the city of Kirikkale. The buildings at the city center are recommended to be assessed with street survey rapid structural evaluation methods so as to mitigate seismic damages. The obtained contour maps in this study are estimated to be effective for visually characterizing the city in terms of the considered parameters.