• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7B
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• pp.1252-1260
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• 1999

The HFC network has a architecture of a star topology in fiber optic trunks, and tree and branch topology is used in the part of coaxial cable. It is well known that the HFC upstream channel is noisy. Ingress, common mode distortion and impulse noise exist in the upstream channel. In order to provide Quality of Service(QoS) to users with real-time data such as voice, video and interactive services, the evolving IEEE 802.14 standard for HFC networks must include an effective priority scheme. The scheme separates and resolves collisions between stations in a priority order. It is important to simulate protocols under a practical environment. The proposed algorithm in this paper is simulated with the assumption that the collision detector made certain mistake due to noises. Simulation results show that the proposed algorithm is more efficient than existing tree-based algorithm under practical environment.

• Journal of the Korean Society for Railway
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• v.17 no.1
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• pp.79-85
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• 2014

This paper presents an evaluation method that considers the weights of many characteristics of a public transportation system; this method facilitates the selection of suitable advanced transit system in a transportation investment plan. The method sets up twelve evaluation items separated by the following influence factors: users, community, government and operators. It then evaluates the advanced transportation system by analyzing the weights. For an empirical analysis, the urban advanced transportation systems for the main transit of small and medium sized cities were evaluated using the AHP method. The result revealed that the weight order is safety, rapidity and punctuality, convenience, and regional activation, and the priority order is steel wheel-type AGT, LIM, and rubber wheel-type AGT.

• Journal of Korea Port Economic Association
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• v.28 no.2
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• pp.29-41
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• 2012

Competition between international Hub ports has been more and more intense. In order to invigorate itself, Gwang-Yang port has been making multilateral efforts. However, it has not still reached 300Millions TEU which is the standard to be permitted as a self-reliance Hub port. Therefore, a functional modification of berth should be considered. This study suggests to transform container berths to general berths. This article is focused on reserve berth mode of Gwang Yang hub port and selected three kinds of berths as alternative subjects of the study: general berth, exclusive berth, and multipurpose berth. This research has conducted that The subjects of the survey were in relation with Logistics as professional mutually group about Gwang-Yang hub port. The measurements of this survey were measure section and factor. Also, Fuzzy AHP(Analytic Hierarchy Process) was applied to the survey. According to the result, by measuring weight values of alternatives, the best favored one was multipurpose berth expect stability (32.6%), Exclusive berth was graded the most among the alternatives. Also, based on total weight value, the order of priority is as follows: multipurpose berth(38.2%), exclusive port(33.7%), general berth(28.1%).

• Journal of Korea Multimedia Society
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• v.13 no.10
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• pp.1463-1473
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• 2010

In this paper, we propose a modified watershed algorithm to extract more correct edge and reduce processing time. Two new algorithms are proposed in this paper. The first one is applying two conventional watershed expansion methods known as rainfall and immersion simulation jointly. We analyze the advantage and problem of each simulation and then propose a new expansion method that keeps the advantage and removes the problem in order to extract more correct edge and reduce processing time. The second is a new priority decision algorithm to obtain more correct edge of a region. Some zero-crossing points of gradient are expected to be edge of a region but the conventional method has a limitation that it cannot extract those points as edge. Therefore we propose a new priority decision algorithm for watershed in order to get more correct edge. We compare the proposed method with the conventional method through experiments and prove that the proposed method can extract more correct edge of region.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.1
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• pp.173-184
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• 2014

Riparian areas are significant functional grounds for inhabiting ecological system on the river such as the self-regulation of the water quality and the foundation of important corridors. For such functional device to operate, consecutive land purchase scheme that prioritizes targeted areas with high pollutant load rate imposes sustainable development of the ecological riparian belt. The purpose of this study is focused on measuring the methodology for selecting land purchse order before establishing riparian belt in accordance with pollution loading estimation and the basin approach. The Yeongsan and Seomjin river which includes targeted areas of the land purchase have been classified into the large-medium-small(standard basin) influence areas based on their catchment rage, which than sub-divided the research area of Juam lake by 38 small basins and 223 units. Small basins with the high pollution load rates have been assessed as the first prioritized targets. For the second priority, the condition of the point pollutant sources, original area of the targets, original restored area were concerned. The final decision of the land purchase order targeted only those within 50 meter range from the basin. To validate the accumulated data, the on-site investigation went along the targeted zones, which the result shows that all prioritized areas included both point and non-point pollutant sources, and had not a small originally restored areas.

• Journal of KIISE:Databases
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• v.36 no.3
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• pp.189-197
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• 2009

Top-k queries are important to many wireless sensor applications. Conventional Top-k query processing algorithms install a filter at each sensor node and suppress unnecessary sensor updates. However, they have some drawbacks that the sensor nodes consume energy extremely to probe sensor reading or update filters. Especially, it becomes worse, when the variation ratio of top-k result is higher. In this paper, we propose a novel Top-k query processing algorithm for energy-efficiency. First, each sensor determines its priority as the order of data gathering. Next, sensor nodes that have higher priority transmit their sensor readings to the base station until gathering k sensor readings. In order to show the superiority of our query processing algorithm, we simulate the performance with the existing query processing algorithms. As a result, our experimental results show that the network lifetime of our method is prolonged largely over the existing method.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.53-64
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• 2019

The term 're-use' here signifies the re-use of end-of-life products without changing their form after they have been thoroughly inspected and cleaned. In the re-use network model, the distributor determines the product order quantity on the network through which new products are received from the suppliers or products are supplied to the customers through re-use of the recovered products. In this paper, we propose a reusable network model for reusable products that considers the total logistics cost from the forward logistics to the reverse logistics. We also propose a reusable network model that considers the processing and disposal costs for reuse in an optimal inventory management environment. The authors employe Genetic Algorithm (GA), which is one of the optimization techniques, to verify the validity of the proposed model. And in order to investigate the effect of the parameters on the solution, the priority-based GA (priGA) under three different parameters and the modified Hybrid GA (mhGA), in which parameters are adjusted for each generation, were applied to four examples with varying sizes in the simulation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.5
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• pp.723-728
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• 2022

The vitality of the city's commercial district, which in the base of city life and provides vitality and diversity of life, has a great impact on the vitality of the entire city and the revitalization of the local economy. The revitalization of the commercial street is related to the activation of walking, and walking is closely related to the quality of life because it involves a wide range of interactions with the surrounding environment beyond simple movement. This quality of life leads to 'Livability'. In order to revitalize pedestrians on the commercial street, the liberty factor was derived and the importance of what was the most important and effective for the activation of the commercial street was analyzed. As a result, it was found that the items representing the atmosphere and purpose, which are detailed indicators of placeness, had a high priority, and it was found that the detailed indicators belonging to accessibility came out with a lower priority. In order to increase the livability of the commercial street, the priority is to increase the spatiality of the space, and if pedestrians are activated as the number of visits and stay time of visitors increases, it can be extended to the vitality of the entire area.

• Journal of Practical Engineering Education
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• v.14 no.3
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• pp.513-522
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• 2022

Course evaluation serves as helpful information to improve the quality of college education and improve lectures. This study derived the factors through preceding research and FGI to explore the factors that constitute course evaluation and identified the relative importance and priority of the factors through the Analytic Hierarchy Process (AHP). For this, it derived five factors and 15 evaluation items as follows. To secure expertise and fairness in the factor development of course evaluation, the researcher conducted a questionnaire surveying students and teachers and collected a total of 20 valid data. The weight of each evaluation item was calculated based on the data that had been verified for consistency. The analysis concluded that students rated class content, class method, class operation, class evaluation, and class plan as the critical factors in the order of importance, while teachers evaluated class content, class operation, class method, class evaluation, and class plan as important, in that order. Based on the results of this study, I hope that various analyses and studies will be conducted to improve the efficiency and reliability of course evaluation for the quality management of college education.

• Journal of the Korea Safety Management & Science
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• v.2 no.2
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• pp.85-94
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• 2000

This paper deals with the selection of a proper dispatching rule for an one-process Job scheduling that follows a particular distribution of an order production. That is, it makes a distribution on an order per unit period and applies to simulation model that uses it. This study consists of two purposes either seeks adequately production scheduling using priority rule or seeks extension of the facilities that increase current production efficiency through computer simulation in scheduling.