• Journal of Korean Society of Forest Science
• /
• v.97 no.6
• /
• pp.611-616
• /
• 2008

The investigation was accomplished on the test area in Forest Practice Research Center in order to compare Point Grid method with Bufferring method in process of the calculation of the Actual Mean Skidding Distance with the GIS aided harvesting method. the investigation site amounted to 264.9 ha in area and 32.67 m in the road density, 306.1 m in road spacing. the Net Correction Factor (Kn) was 1.53 in both sides skidding. the theoretical mean skidding distance was 72.52 m. the shortest mean skidding distance amounted to 149.57 m with point grid method and 139.68 m with Buffering methode. skidding distance correction factor (Kr) was 2.15. actual mean skidding distance amounted to 251.51 m and factor of wood assortment skidding (Kg) was 3.29. when the tractor (Dongyang) and tower yader (Koller 303) are used on investigation site, the logging cost is calculated 11,808 Won with Tractor below 25% slope and 12,336 won with Tractor between 25~55% slope, 10,020 won with Tower Yarder more than 55% slope.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2013.07a
• /
• pp.75-76
• /
• 2013

본본 논문에서는 Space Syntax 이론에 기반하여 여성의 안전한 여가활동 경로를 추천하는 어플리케이션을 제안한다. 이 어플리케이션은 접근성, 지역 간 상호관계 등을 바탕으로 한 계산을 통해 추천경로를 만든다. 이는 일반적인 네비게이션이 가지는 최단시간, 최단거리 탐색과는 차별성을 가지며, 안전을 최우선으로 한 경로를 탐색한다. 오늘날 늘어난 여가시간에 따라 사람들의 레저 활동이 많아지며, 따라서 여성의 경우도 참여율에 높아진다. 이 때 여성의 경우 안전적 문제에 있어 레저 활동 장소까지의 경로를 추천하고자 한다. 본 논문에서는 제안하는 레저활동과 여성안전에 관련한 어플리케이션은 다양한 위험요소를 염두에 두어 계산을 통해 안전한 경로를 제공하는 알고리듬으로 주관적 선택사항을 적용하여, 자기맞춤형 경로를 선택 가능하게 한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.30 no.5
• /
• pp.425-433
• /
• 2012

Dijkstra's algorithm is one of well-known methods to find shortest paths over a network. However, more research on $A^*$ algorithm is necessary to discover the shortest route to a goal point with the heuristic information rather than Dijkstra's algorithm which aims to find a path considering only the shortest distance to any point for an optimal path search. Therefore, in this paper, we compared Dijkstra's algorithm and $A^*$ algorithm for bicycle route selection. For this purpose, the horizontal distance according to slope angle and average speed were calculated based on factors which influence bicycle route selection. And bicycle routes were selected considering the shortest distance or time-dependent shortest path using Dijkstra's or $A^*$ algorithm. The result indicated that the $A^*$ algorithm performs faster than Dijkstra's algorithm on processing time in large study areas. For the future, optimal path selection algorithm can be used for bicycle route plan or a real-time mobile services.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.05a
• /
• pp.171-173
• /
• 2022

The 4th industrial revolution technology is developing people's lives more efficiently. GIS provided on the Internet services such as traffic information and time information makes people getting more quickly to destination. National geographic information service(NGIS) and each local government are making basic data to investigate SOC accessibility for analyzing optimal point. To construct the shortest distance, the accessibility from the starting point to the arrival point is analyzed. Applying road network map, the starting point and the ending point, the shortest distance, the optimal accessibility is calculated by using Dijkstra algorithm. The analysis information from multiple starting points to multiple destinations was required more than 3 steps of manual analysis to decide the position for the optimal point, within about 0.1% error. It took more time to process the many-to-many (M×N) calculation, requiring at least 32G memory specification of the computer. If an optimal proximity analysis service is provided at a desired location more versatile, it is possible to efficiently analyze locations that are vulnerable to business start-up and living facilities access, and facility selection for the public.

• Journal of the Economic Geographical Society of Korea
• /
• v.11 no.3
• /
• pp.459-475
• /
• 2008

This study analyzes the network structure of the Metropolitan Seoul subway system by applying complex network analysis methods. For the purpose, we construct the Metropolitan Seoul subway system as a network graph, and then calculate various indices introduced in complex network analysis. Structural characteristics of Metropolitan Seoul subway network are discussed by these indices. In particular, this study determines the shortest paths between nodes based on the weighted distance (physical and time distance) as well as topological network distance, since urban travel movements are more sensitive for them. We introduce an accessibility measurement based on the shortest distance both in terms of physical distance and network distance, and then compare the spatial structure between two. Accessibility levels of the system have been getting up overall, and thus the accessibility gaps have been getting lessen between center located subway stops and remote ones during the last 10 years. Passenger traffic volumes are explored from real passenger transaction databases by utilizing data mining techniques, and mapped by GIS. Clear differences reveal between the spatial patterns of real passenger flows and accessibility. That is, passenger flows of the Metropolitan Seoul subway system are related with population distribution and land use around subway stops as well as the accessibility supported by the subway network.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.04a
• /
• pp.331-333
• /
• 2001

현재 사용되고 있는 라우팅 프로토콜들은 정적인 인자를 사용하여 최단 거리 경로를 설정하기 때문에 혼잡(Congestion)이 자주 발생 할 뿐 아니라 최단 거리 경로를 설정하는 이들 라우팅 프로토콜로는 혼잡상황을 해결하기 어렵다. 이를 해결하기 위해서 트래픽 엔지니어링 기법이 등장하게 되었다. 트랙픽 엔지니어링을 위해서는 네트워크의 동적인 상태를 반영하는 정보를 저장하는 트래픽 엔지니어링 데이터베이스가 필요하다. 현대 NS-2에는 프래픽 엔지니어링에 필요한 정보를 제공하고, 네트워크의 상태에 따라 동적으로 경로를 설정하는 라우팅 프로토콜이 구현되어 있지 않다. 본 논문에서는 NS-2에 구현되어 있는 rtProtoLS라는 Link-State Protocol을 수정하여 플러딩(Flooding) 하는 정보에 동적인 인자의 하나인 가용 대역폭을 정보를 실어서 트래픽 엔지니어링 데이터베이스에 제공 할 수 있도록 하고, 가용 대역폭 정보를 기반으로 하여 동적으로 새로운 경로를 계산 할 수 있는 기능을 추가한 QoS를 고려한 Link-State Protocol(QLS)을 구현하였다. 그리고 본 논문에서는 기존의 라우팅 기법 중 거리 백터 프로토콜(Distance Vector Protocol) 라우팅과 QLS 라우팅의 성능을 Throughput 측면에서 비교, 분석했다.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2021.07a
• /
• pp.655-658
• /
• 2021

본 논문에서는 GPU 아키텍처를 이용하여 적응형 부호 거리장을 최적화하여 빠르게 구축하고 시각화 할 수 있는 방법에 대해 제안한다. 쿼드트리를 효율적으로 GPU 메모리로 전달하고, 이를 활용하여 삼각형에 대해 유클리디안 거리를 각 스레드 별로 병렬처리하여 최단 거리를 찾는다. 이 과정에서 GPU를 사용하여 삼각형으로 구성된 3D 메쉬로부터 빠르게 적응형 부호 거리장을 계산할 수 있는 최적화 기법과 절단면 보기, 특정 위치의 값 조회, 실시간 레이트레이싱 및 충돌처리 작업을 빠르고 효율적으로 수행할 수 있는지를 보여준다. 또한, 제안하는 프레임워크를 활용하면 하이 폴리곤 메쉬도 1초 내외로 부호 거리장을 계산할 수 있기 때문에 강체뿐만 아니라 변형체에도 충분히 활용될 수 있다.

• Journal of KIISE:Computer Systems and Theory
• /
• v.35 no.8
• /
• pp.385-393
• /
• 2008

The best coverage problem is finding a path whose worst distance to the sensor-set is the best among all paths. Instead, if the user stays close to its nearest two sensors, then the stability of the wireless connection may be guaranteed. So we consider the problem of finding a second best coverage path; given the sensor set U, a starting point s and a target point t, find a path whose worst distance to the second closest sensor is minimized. This paper presents an O(n logn) -time algorithm to find such a path. We also give experimental evidence showing that the connection to the sensor-set along a second best coverage path is more stable than that along the best coverage path.

• Journal of the Korean Regional Science Association
• /
• v.33 no.1
• /
• pp.29-41
• /
• 2017

This study proposes an integrated accessibility measurement algorithm, which is applied to the Seoul Metropolitan public transportation system consisting of bus and subway networks, and analyzes the result. We construct a public transportation network graph linking bus-subway networks and take the time distance as the link weight in the graph. We develop a time-distance algorithm to measure the time distance between each pair of transit stations based on the T-card transaction database. The average travel time between nodes has been computed via the shortest-path algorithm applied to the time-distance matrix, which is obtained from the average speed of each transit route in the T-card transaction database. Here the walking time between nodes is also taken into account if walking is involved. The integrated time-distance accessibility of each node in the Seoul Metropolitan public transportation system has been computed from the T-card data of 2013. We make a comparison between the results and those of the bus system and of the subway system, and analyze the spatial patterns. This study is the first attempt to measure the integrated time-distance accessibility for the Seoul Metropolitan public transportation system consisting of 16,277 nodes with 600 bus routes and 16 subway lines.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.10
• /
• pp.115-120
• /
• 2009

In this parer, we design the artificial intelligent direction escape light control system to improve/complete the defects of the existing fire fighting system, and sketch an optimum escape guide algorithm for its implementation. It intends to minimize human casualties and injuries by calculating/predicting moving line of the optimum emergency escape, by means of interlocking the sensor and the reception group and analyzing the data of the combustion point and the smoke movement. The optimum escape algorithm is designed by FLOYD algorithm which calculates the shortest distance. It consists of the measuring method which calculates the shortest distance by using hazardous factors for each condition in danger which is judged by the sensor installed in each area.