• Journal of agriculture & life science
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• v.46 no.1
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• pp.83-90
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• 2012

This study was undertaken to analyze 1) the growth characteristics for the optimal planting density and 2) reached ages of sap tapping for the planting timing of Acer okamotoanum in natural and plantation stand. Soil in natural stand was significantly more fertile than that of plantation stand. Early growth of A. okamotoanum in plantation stand was affected by planting density. Results showed that there was a positive relationship between the DBH and crown width in both natural and plantation stands. Reached ages by DBH were no significant difference in natural stands. Reached ages on DBH 10 cm were approximately 19 and 9 in natural and plantation stands, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.6
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• pp.1132-1136
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• 2006

In this paper, we analyze reachable/nonreachable states of 3-neighborhood cellular automata and propose the algorithm finding the predecessor of a reachable state.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.78-83
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• 2002

Reachability analysis of finite state machines is very useful for many computer-aided design applications such as communication protocol or microprecessor design. We present new techniques to improve approximate reachability analysis. The key idea is to used an iterative approximate reachability analysis technique in which don't care sets derived from previous iterations are used to improve the approximation in subsequent iterations. Experimental results show that the new techniques can improve reachability analysis significantly compared to existing analysis techniques.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.323-323
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• 2011

산지가 많은 국내의 지형적인 여건은 토지의 이용에 다양한 영향을 준다. 산지주변에서는 능선을 따르거나 가로지르는 도로가 건설되고 산지계곡 하류에 발달한 선상지에는 가옥이 들어서거나 경작지로 활용되고 있다. 이러한 환경에서 우리나라는 지난 10년간 사면재해로 인한 사망자가 전체 자연재해에 27%에 달하고 이는 집중호우가 발생하는 시기에 집중되고 있어 이에 대한 연구가 필요한 실정이다. 본 연구에서는 호우 발생 시 산지하천에서 발생하는 토석류의 흐름특성을 연구하기 위해 국내 외 토석류 실험장치에 대한 조사와 토석류 실험장치를 개발하여 토석류발생 및 도달거리 예측을 위한 실험을 수행하였다. 토석류 실험장치는 수조길이 5.5m에 10-40cm의 가동폭 그리고 상 중 하류의 3단계 경사조절이 가능하며 토석류 퇴적장치를 결합하여 도달거리 및 퇴적분포를 계측할 수 있다. 토석류를 발생시키기 위해 토사공급장치 이용방법, 하상퇴적토사를 이용한 방법 등 다양한 시도를 하였다. 토석류 실험장치를 이용하여 발생시킨 토석류의 특성과 퇴적장치 에서의 도달거리를 측정하여 유량공급과의 상관관계를 분석하였다. 이러한 연구결과는 토석류 재해지도의 작성이나 토석류 해석모형의 개발에 필요한 기초자료로 활용될 수 있다.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.593-598
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• 2015

Non-linear cellular automata is difficult to analyze mathematically than linear cellular automata. So it is difficult to identify reachable states and attractors of nongroup non-linear cellular automata than nongroup linear cellular automata. In this paper, we propose a new reachable table to overcome these problems. We can see the next state for all the states of the non-linear cellular automata by the proposed reachable table. In addition, we can identify reachable states and attractors by the reachable table.

• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.15-21
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• 2022

The purpose of this study is to investigate the sedimentation area and runout distance in the downstream when debris flow occurred on a mountain slope through an experimental performance. Super typhoons and torrential rains caused by climate change cause large-scale debris flow disasters in the downstream areas of mountainous areas, mainly where sediments are deposited and flowed downstream. To analyze the characteristics of the sediment deposited downstream, the disposition area and runout distance were investigated through experiments in the case of a straight channel and channel with berm, respectively. As experimental conditions, changes in sediment volume concentration and channel slope, and channel with or without berm, reduction rates in sedimentation area and runout distance were investigated. In the straight channel, the steeper the channel slope and the lower the sedimentation concentration, the sedimentation area and runout distnace were increased. In a channel with berm, the runout distance and sediment area increased as the slope became steeper and the sediment area decreased.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.6
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• pp.599-607
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• 2000

This paper suggests an efficient reachability analysis method of bounded petri nets. Reachability analysis is a fundamental basis for studying the dynamic properties of any discrete event systems. However, it takes at least exponential execution time and memory space to verify in general petri nets. That is, state space explosion problem may occur. In this paper, we attack problems of previous approaches - state space explosion and restrictions to applicable petri net classes - by formulating the reachability problem as set operation over structural relations among places on an unfolding.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.745-752
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• 2005

BGP is a unique routing protocol in broadband internet. It chooses routing paths considering internet hierarchy and local policies. As BGP routers selectively bypass routing information to a subset of neighboring BGP routers, connectivity by way of a series of links between source and destination nodes does not mean reachability of routing information of the two. In emergency when BGP routers or links over wide range are not available, BGP routers have to use links that are not normally used to keep reachability. This paper listed out the requirements for BGP backup routing and proposed a routing solution that hides most demerits in currently published ones. The proposed backup operates in three tiers according to network damage. Under this rule, BGP routers use tier-0 routing paths at normal. If networks are impaired, they choose tier-1 paths. If networks are seriously damaged, tier-2 paths are allowed to use. Also this paper proves that the proposed backup guarantees stability and safeness. As results, the proposed backup is very adaptive to light network damages as well as serious ones and provides strong routing reachability at all times.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11C
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• pp.957-964
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• 2010

In this paper, we propose an indoor positioning algorithm based on 3 points near field angle-of-arrival estimation without side information. The conventional angle-of-arrival based positioning scheme requires the distance between the listener and the center of two points which is obtained by a received signal strength based range estimation. However, a received signal strength is affected by structure of room, placement of furniture, and characteristic of signal, these effects cause a large error to estimation of angle. In this paper, the proposed positioning scheme based on near field angle-of-arrival estimation can be used to estimate the position of listener without a prior distance information, just using time-difference-of-arrival information given from 3 points microphones. The performance of the proposed scheme is shown by cumulative distribution function of root mean squared error.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.4 s.23
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• pp.37-47
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• 2006

Urban development results in increased runoff volume and flowrates and shortening in time of concentration, which may cause frequent flooding downstream. Flow retardation structures to limit adverse downstream effects of urban storm runoff are used. There are various types of flow retardation measures include detention basins, retention basins, and infiltration basins. In basic planning phase, a number of planning models of detention ponds which decide storage volume by putting main variables were used to design detention ponds. The characteristics of hydrological parameters $\alpha,\;\gamma$ which are used in planning models of detention pond were analyzed. In this study, detention ponds data of Disaster Impact Assessment report at 22 sites were analyzed in order to investigate correlation between characteristic of urban drainage basin parameter and characteristics of detention pond parameter due to urbanization effects. The results showed that storage volume was influenced by peak discharge ratio $\alpha$ more than runoff coefficient ratio $\beta$ and peak discharge ratio $\alpha$ was influenced by runoff coefficient ratio $\beta$ less than regional parameter n. Storage ratio was mainly influenced by duration of design rainfall in the case of trapezoidal inflow hydrograph such as Donahue et al. method.