• Journal of Communications and Networks
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• 제10권2호
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• pp.204-212
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• 2008

We study the routing problem in all-wireless networks based on cooperative transmissions. We model the minimum-energy cooperative path (MECP) problem and prove that this problem is NP-complete. We hence design an approximation algorithm called cooperative shortest path (CSP) algorithm that uses Dijkstra's algorithm as the basic building block and utilizes cooperative transmissions in the relaxation procedure. Compared with traditional non-cooperative shortest path algorithms, the CSP algorithm can achieve a higher energy saving and better balanced energy consumption among network nodes, especially when the network is in large scale. The nice features lead to a unique, scalable routing scheme that changes the high network density from the curse of congestion to the blessing of cooperative transmissions.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권5호
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• pp.492-498
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• 2017

Subsea pipeline route design is a crucial task for the offshore oil and gas industry, and the route selected can significantly affect the success or failure of an offshore project. Thus, it is essential to design pipeline routes to be eco-friendly, economical and safe. Obstacle avoidance is one of the main problems that affect pipeline route selection. In this study, we propose a technique for designing an automatic obstacle avoidance. The Laplacian smoothing algorithm was used to make automatically generated pipeline routes fairer. The algorithms were fast and the method was shown to be effective and easy to use in a simple set of case studies.

• 제어로봇시스템학회논문지
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• 제17권3호
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• pp.199-205
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• 2011

This paper presents an algorithm capable of detecting free space for the autonomous vehicle navigation. The algorithm consists of two main steps: 1) estimation of longitudinal profile of road, 2) detection of free space. The estimation of longitudinal profile of road is detection of v-line in v-disparity image which is corresponded to road slope, using v-disparity image and hough transform, Dijkstra algorithm. To detect free space, we detect u-line in u-disparity image which is a boundary line between free space and obstacle's region, using u-disparity image and dynamic programming. Free space is decided by detected v-line and u-line. The proposed algorithm is proven to be successful through experiments under various traffic scenarios.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1338-1341
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• 2004

In this paper, we have proposed a new approach of routing and wavelength assignment algorithms, called Possible Available Wavelength (PAW) algorithm. The weight of a link is used as the main factor for routing decision in PAW algorithm. The weight of a link is defined as a function of hop count and available wavelengths. This function includes a determination factor of the number of wavelengths that are being used currently and are supposed to be available after a certain time. The session requests from users will be routed on the links that has the greatest number of link weight by using Dijkstra's shortest path algorithm. This means that the selected lightpath will has the least hop count and the greatest number of possible available wavelengths. The impact of proposed link weight computing function on the blocking probability and link utilization is investigated by means of computer simulation and comparing with the traditional mechanism. The results show that the proposed PAW algorithm can achieve the better performance in terms of the blocking probability and link utilization.

• 한국컴퓨터정보학회논문지
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• 제28권3호
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• pp.11-16
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• 2023

실내 측위를 위한 기법으로 Fingerprinting, 삼변 측량을 이용한 실내 위치 측위 방법, Wi-Fi / Bluetooth 등 장비로 얻은 정보를 활용하여 사용자의 실내 위치를 특정 하는 것이 일반적이고 대표적인 방법이다. 하지만 이러한 방법들은 실내 공간이 다수의 장비(AP, Beacon)를 설치할 수 있을 만큼의 장소가 마련되어야 한다. 본 논문에서는 폭이 좁은 건물 등 기존 방식을 적용할 수 없는 건물 구조에서 GPS 신호와 비콘 으로부터 전달된 신호를 동시에 이용하여 건물 내 사용자의 위치를 표현할 수 있는 기법을 제안한다. 또한 최단 경로 탐색을 위해 가장 대표적이고 효율적인 최단 경로 탐색 알고리즘 중의 하나인 다익스트라 알고리즘(Dijkstra Algorithm)를 적용하여 최단 경로 탐색 시스템을 설계 구현했다. 제안된 기법은 향후 건물 구조 특성을 고려한 사용자 실내 위치 측정 방법 중 하나로 고려될 수 있을 것이다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.171-173
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• 2022

4차 산업혁명 기술은 국민들의 생활을 효율적인 방향으로 발전시키고 있다. 인터넷 상에서 제공되는 GIS는 국민이 원하는 목적지에 빠르게 도달할 수 있도록 교통안내, 시간안내 등의 서비스를 제공한다. 국토지리정보원과 지방자치단체들은 생활 SOC 접근성을 조사하여 최적지점 분석에 활용하기 위한 기초 자료를 제작하고 있으며, 본 연구는 최단거리 구성을 위하여 출발점에서 도착점까지의 접근성을 분석하였다. Dijkstra알고리즘을 활용하여 도로망도와 출발지점, 도착점을 통해 최단거리를 계산하고 이를 활용하여 최적의 접근성을 계산하였다. 연구 결과 다수의 도착점에 대한 분석을 수행한 경우 약 0.1% 이상의 오류가 나타났으며, 최적지점을 위한 위치 분석을 위하여 3번 이상의 분석이 필요하였다. 다대다(M × N) 계산을 처리할 경우 더 많은 시간이 소요되었으며, 본 분석을 위해 32G이상의 메모리 사양이 요구되었다. 범용적인 최적 접근성 분석 서비스의 제공은 기업의 창업 및 생활 시설의 위치 선정에 효과적으로 이용될 수 있으며, 국민 누구나 시설 및 주거지 선정 시 서비스를 활용할 수 있다. 본 연구를 기반으로 효율적이고 편한 푸시 서비스를 국민과 정부기관에 제공한다면 국가와 사회의 발전에 이바지 될 것이다.

• Management Science and Financial Engineering
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• 제4권2호
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• pp.1-13
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• 1998

The Shortest Path Problem in Time-dependent Networks, where the travel time of each link depends on the time interval, is not realistic since the model and its solution violate the Non-passing Property (NPP:often referred to as FIFO) of real phenomena. Furthermore, solving the problem needs much more computational and memory complexity than the general shortest path problem. A new model for Time-dependent Networks where the flow speeds of each link depend on time interval, is suggested. The model is more realistic since its solution maintains the NPP. Solving the problem needs just a little more computational complexity, and the same memory complexity, as the general shortest path problem. A solution algorithm modified from Dijkstra's label setting algorithm is presented. We extend this model to the problem of Minimum Expected Time Path in Time-dependent Stochastic Networks where flow speeds of each link change statistically on each time interval. A solution method using the Kth-shortest Path algorithm is presented.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.191-194
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• 2003

Location-allocation problem is known as one of the important problem faced in Industrial Engineering and Operations Research fielde. There are many variations on this problem for different applications, however, most of them consider no obstacle existing. Since the location-allocation problem with obstacles is very complex and with many infeasible solutions, no direct method is effective to solve it. In this paper we propose a hybrid Genetic Algorithm (hGA) method for solving this problem. The proposed hGA is based on Lagrangian relaxation method and Dijkstra's shortest path algorithm. To enhance the proposed hGA, a Fuzzy Logic Controller (FLC) approach is also adopted to auto-tune the GA parameters.

• Journal of Information Processing Systems
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• 제6권3호
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• pp.375-384
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• 2010

Trajectory modeling is foundational for 4D-Route modeling, conflict detection and air traffic flow management. This paper proposes a novel algorithm based Vincenty's fomulas for trajectory calculation, combined with the Dijkstra algorithm and Vincenty's formulas. Using flight plan simulations our experimental results show that our method of En-route trajectory calculation exhibits much improved performance in accuracy.

• Journal of Communications and Networks
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• 제7권4호
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• pp.499-508
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• 2005

In this paper, we address the problem of efficient routing and wavelength assignment (RWA) in multi-fiber wavelength division multiplexing (WDM) networks without wavelength translation, under dynamic traffic. We couple Dijkstra's shortest path algorithm with a suitable weight function which chooses optical paths based both on wavelength availability and multi-fiber segments. We compare our approach with other RWA schemes both for regular and irregular WDM multi-fiber network topologies in terms of blocking probability and overall link utilization.