• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.1
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• pp.8-13
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• 2006

In mobile ad hoc networks, most of on demand routing protocols such as DSR and AODV do not deal with traffic load during the route discovery procedure. To achieve load balancing in networks, many protocols have been proposed. However, existing load balancing schemes do not consider the remaining available buffer size of the interface queue, which still results in buffer overflows by congestion in a certain node which has the least available buffer size in the route. To solve this problem, we propose a load balancing protocol called Dynamic Congestion Aware Routing Protocol (DCAR) which monitors the remaining buffer length of all nodes in routes and excludes a certain congested node during the route discovery procedure. We also propose two buffer threshold values to select an optimal route selection metric between the traffic load and the minimum hop count. Through simulation study, we compare DCAR with other on demand routing protocols and show that the proposed protocol is more efficient when a network is heavily loaded.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.285-291
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• 2022

WSN is the major component for information transfer in IoT environments. Source Location Privacy (SLP) has attracted attention in WSN environments. Effective SLP can avoid adversaries to backtrack and capture source nodes. This work presents a Two-Level Randomized Sector-based Routing (TLRSR) model to ensure SLP in wireless environments. Sector creation is the initial process, where the nodes in the network are grouped into defined sectors. The first level routing process identifies sector-based route to the destination node, which is performed by Ant Colony Optimization (ACO). The second level performs route extraction, which identifies the actual nodes for transmission. The route extraction is randomized and is performed using Simulated Annealing. This process is distributed between the nodes, hence ensures even charge depletion across the network. Randomized node selection process ensures SLP and also avoids depletion of certain specific nodes, resulting in increased network lifetime. Experiments and comparisons indicate faster route detection and optimal paths by the TLRSR model.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.3
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• pp.369-374
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• 2005

Currently, ECDIS and GPS plotters are much used as equipment providing operators with route information, but they do not have any function of automatic route creation and route explanation, so available for only experienced operators. Especially, the present situation is that no study is made of the automatic route creation and route explanation using ENC for ECDIS, substitution system of paper chart. ENC is the electronic navigation chart that is produced using S-52, 5-57 standard format required by IHO. In this paper, an Navigation Guiding System(NGS) is proposed to generate an optimal route where ENC and GPS data is fusioned including the wind direction and speed of an anemometer. The proposed system was testified by a simulation, and its effectiveness was verified.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.15 no.4
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• pp.268-276
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• 2015

A ship's sailing route or plan is determined by the master as the decision maker of the vessel, and depends on the characteristics of the navigational environment and the conditions of the ship. The trajectory, which appears as a result of the ship's navigation, is monitored and stored by a Vessel Traffic Service center, and is used for an analysis of the ship's navigational pattern and risk assessment within a particular area. However, such an analysis is performed in the same manner, despite the different navigational environments between coastal areas and the harbor limits. The navigational environment within the harbor limits changes rapidly owing to construction of the port facilities, dredging operations, and so on. In this study, a support vector machine was used for processing and modeling the trajectory data. A K-fold cross-validation and a grid search were used for selecting the optimal parameters. A complicated traffic route similar to the circumstances of the harbor limits was constructed for a validation of the model. A group of vessels was composed, each vessel of which was given various speed and course changes along a specified route. As a result of the machine learning, the optimal route and voyage data model were obtained. Finally, the model was presented to Vessel Traffic Service operators to detect any anomalous vessel behaviors. Using the proposed data modeling method, we intend to support the decision-making of Vessel Traffic Service operators in terms of navigational patterns and their characteristics.

• Journal of Korean Society of Transportation
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• v.23 no.3 s.81
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• pp.35-47
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• 2005

This paper is to review a literature concerning Bus Transit Route Network Design(BTRNDP), to describe a future study direction for a systematic application for the BTRNDP. Since a bus transit uses a fixed route, schedule, stop, therefore an approach methodology is different from that of auto network design problem. An approach methodology for BTRNDP is classified by 8 categories: manual & guideline, market analysis, system analytic model. heuristic model. hybrid model. experienced-based model. simulation-based model. mathematical optimization model. In most previous BTRNDP, objective function is to minimize user and operator costs, and constraints on the total operator cost, fleet size and service frequency are common to several previous approach. Transit trip assignment mostly use multi-path trip assignment. Since the search for optimal solution from a large search space of BTRNDP made up by all possible solutions, the mixed combinatorial problem are usually NP-hard. Therefore, previous researches for the BTRNDP use a sequential design process, which is composed of several design steps as follows: the generation of a candidate route set, the route analysis and evaluation process, the selection process of a optimal route set Future study will focus on a development of detailed OD trip table based on bus stop, systematic transit route network evaluation model. updated transit trip assignment technique and advanced solution search algorithm for BTRNDP.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.761-770
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• 2009

The energy efficiency and environment-friendly aspect of the railway system would be superior to other on-land ransportation systems. In a preliminary feasibility study stage and selection of optimal railway route, the energy efficiency and problems related to environment are usually considered. For the selection of optimal railway route, geographical features and facility of management are generally considered. Environment effect factors for the selection of environment-friendly railway router are focused and studied in this paper. In this study, various analysis of opinion of specialists (railway, environment, transport, urban planning, survey) and the guideline for construction of environment-friendly railway were accomplished. From these results of various analysis, 7 major categories (topography/geology, flora and fauna, Nature Property, air quality, water quality, noise/vibration, visual impact/cultural assets) were extracted. To select environment friendly railway route, many alternatives should be compared optimal route must be selected by a comprehensive assessment considering these 7 categories. To solve this problem, the selected method was AHP which simplifies the complex problems utilizing hierarchy, quantifying qualitative problems through 1:1 comparison, and extracting objective conclusions by maintaining consistency. As a result, a GUIbased program was developed which provides basic values of weighted parameters of each category defined by specialists, and a quantification of detailed assessment guidelines to ensures consistency.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.2 s.6
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• pp.199-211
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• 1995

Bus, Which is together with subway the main part of public transportation modes in the city, is reviewed for the development of an optimal feeder-bus service area. Based on the IDRISI of GIS package, and taking into account of the convenience of downtown-oriented public transportation users at peak time, a model for the development of feeder-bus service area and a solution and introduced. Major result in this study is as follows: Development is given to a model that is designed to overcome the shortage of the existing models, which has limits in simulating the real situation; Variables were used in combination so that bus and subway route, station spacing, and operating frequency can be determined simultaneously, which enables to elucidate the mutual relationship and the structure in public transportation system. A model for feeder-bus area development is also given applied to determination and opening of subway and urban express bus route and new transportation systems. The model developed in this paper is useful in the case of extension and opening of subway and urban express bus route and new transportation Systems.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.4
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• pp.335-342
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• 2000

This study is to integrate and to analyzegraphic and attribute data in features which should be preceding for the ITS construction. A 1:5000 scale map as a national basemap was used and was checked for feasibility. For the convenience of position confirmation, the analysis component was developed and was linked to addresses. Also, the attribute information was considered on the shortest route, and optimal route was selected by investigating traffic volumes on main crossroads depending on the time zone. The optimal route could be selected by analyzing user's demands, position and statistical data, and the position information could be provided efficiently by combining the graphic information with the land register information.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.361-366
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• 2006

It is widely known that the dynamic optimal path algorithm, adopting real-time path finding, can be supporting an optimal route with which users are satisfied economically and accurately. However, this system has to search optimal routes frequently for updating them. The proposed concept of optimizing search area lets it reach heuristic optimal path rapidly and efficiently. Since optimal path should be increased in proportion to an distance between origin and destination, tremendous calculating time and highly efficient computers are required for searching long distance journey. In this paper, as a result of which the concepts of partial solution and representative path are suggested. It was possible to find an optimal route by decreasing a half area in comparison with the previous method. Furthermore, as the size of the searching area is uniform, comparatively low efficient computer is required for long distance trip.

• 한국기계연구소 소보
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• s.14
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• pp.145-155
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• 1985

The recent trend in shipbuilding technology is toward development of highly economical vessels of which construction and operation costs are minimized, whereas cargo transport capacity is maximized. But, most of the vessel which are now operated by some of the nation's shipping companies are uneconomical ones built before oil crisis and consequently the companies are suffering from long-lasted deficit problem. In this paper, derivation study of optimum vessel for multi purpose cargo vessel on south-East Asian trade route is carried out to solve this problem. The Required Freight Rate is used as a measure of merits.