• Journal of Energy Engineering
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• v.26 no.2
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• pp.99-120
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• 2017

In SS branch of Korea District Heating Corporation, Combined Heat & Power power plant with 99MW capacity and 98Gcal / h capacity is operated as a district electricity business. In this region, it is difficult to operate the generator due to the problem of surplus heat treatment between June and September due to the economic recession and the decrease in demand, so it is urgent to develop an economical energy new business model. In this study, we will develop an optimized operation model by introducing a renewable energy hybrid system based on actual operation data of this site. In particular, among renewable energy sources, fuel cell (Fuel Cell) power generation which can generate heat and electricity at the same time with limited location constraints, photovoltaic power generation which is representative renewable energy, ESS (Energy Storage System). HOMER (Hybrid Optimization of Multiple Energy Resources) program was used to select the optimal model. As a result of the economic analysis, 99MW CHP combined cycle power generation is the most economical in terms of net present cost (NPC), but 99MW CHP in terms of carbon emission trading and renewable energy certificate And 5MW fuel cells, and 521kW of solar power to supply electricity and heat than the supply of electricity and heat by 99MW CHP cogeneration power, it was shown that it is economically up to 247.5 billion won. we confirmed the results of the improvement of the zone electricity business condition by introducing the fuel cell and the renewable energy hybrid system as the optimization process model.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.1
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• pp.53-66
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• 1999

Limited landfill area and finance as well as a large generation of food wastes, have called for systematic approaches towards potential cost savings. In this study, the regional management system of food wastes generated from the residential and commercial sources was considered in three cities bounded each other; Changwon, Masan, and Jinhae city. Total thirteen alternatives were established and compared by applying the WRAP (Waste Resource Allocation Program). The following results were obtained: 1. While relatively small amounts were generated from the commercial sources such as cafeteria, restaurants, and market facilities, almost 80% of food wastes were generated from the residential sources. 2. Unit costs for food waste management in three cities were different according to their present situation such as the type and location of major generation sources and treatment facilities. Especially, the highest cost appeared in Jinhae city due to the most expensive construction of coastal landfill site. 3. Considering proper revenue, the whole conversion of food waste into animal feed was selected as the optimal alternative and represented 60% to 74% of the management cost of the whole landfill alternative in all cities. Comparing the other alternatives, composting of food waste was more economical than landfill alternative and the incineration was the most expensive alternative. 4. Some of the regional management systems using common food waste processing facilities together in three cities showed to be more economical than the single management system. Therefore, more detailed research for the regional management systems of food waste was recommended.

• The Transactions of the Korea Information Processing Society
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• v.5 no.10
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• pp.2627-2640
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• 1998

In this paper, we analyze the performance of the virtual cell system[1] for the transmission of IP datagrams in mobile computer communications. A virtual cell consistsof a group of physical cells shose base stationsl are implemented b recote bridges and interconnected via high speed datagram packet switched networks. Host mobility is supported at the data link layer using the distributed hierachical location information of mobile hosts. Given mobility and communication ptems among physical cells, the problem of deploying virtual cells is equivalent to the optimization cost for the entire system where interclster communication is more expesive than intracluster communication[2]. Once an iptimal partitionof disjoint clusters is obtained, we deploy the virtual cell system according to the topology of the optimal partition such that each virtual cell correspods to a cluser. To analyze the performance of the virtual cell system, we adopt a BCMP open multipel class queueing network model. In addition to mobility and communication patterns, among physical cells, the topology of the virtual cell system is used to determine service transition probabilities of the queueing network model. With various system parameters, we conduct interesting sensitivity analyses to determine network design tradeoffs. The first application of the proposed model is to determine an adequate network bandwidth for base station networking such that the networks would not become an bottleneck. We also evaluate the network vlilization and system response time due to various types of messages. For instance, when the mobile hosts begin moving fast, the migration rate will be increased. This results of the performance analysis provide a good evidence in demonsratc the sysem effciency under different assumptions of mobility and communication patterns.

• Journal of Korean Society of Transportation
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• v.25 no.3
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• pp.145-154
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• 2007

Determining stop spacing is a very important process in transit system planning. This study is involved in an analytical approach to decide the transit stop spacing. Transit stop spacing should be longer as 1) user access speed, 2) user travel time, and 3) dwell time increase, and shorter as 1) passengers (boardings and alightings) and 2) headway increase. In this study, a methodology is proposed to determine transit stop spacing to minimize total cost (user cost plus operator cost) with irregular passenger distribution (boardings and alightings) Without considering in-vehicle passengers, the transit stop spacing should be shorter in the concentrated sections of the passenger distribution than in others to minimize total cost. Through the conceptual analysis, it is verified that the transit stop spacing could be longer as the in-vehicle passengers increase in certain sections. This study proposes a simple practical method to determine transit stop spacing and locations instead of a dynamic programming method which generally includes a complex and difficult calculation. If the space axis is changed to a time axis. the methodology of this study could be expanded to analyze a solution for the transit service (or headway) schedule problem.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.5-14
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• 2018

Recently the construction of solar plant showed a steady growth in influence of renewable energy policy. It is very important to determine the optimal location and aspect of solar panel using analyzed data of solar radiation to solar plant area beforehand. This study analyzed solar radiation in solar plant area using DEM acquired from UAV geospatial information. Mean solar radiation of 2017 was calculated as $1,474,466W/m^2$ and total solar radiation of 2017 considering solar plant area showed $33,639MW/m^2$ on analyzed result. It is important to analyze monthly solar radiation in aspect of maintenance works of solar plant. Monthly solar radiation of May to July was calculated over $160,000W/m^2$ and that of January to February and November to December showed under $80,000W/m^2$ in monthly solar radiation analysis of solar plant area. Also this study compared with solar radiation being calculated from UAV geospatial information and that of National Institute of Meteorological Sciences. And mean solar radiation of study area showed a little high in comparison with whole country data of National Institute of Meteorological Sciences, because the 93.7% of study area was composed of south aspect. Therefore this study can be applied to calculate solar radiation in new developed solar plant area very quickly using UAV.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.4
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• pp.101-111
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• 2014

Spatial events are predictable using data mining classification algorithms. Decision trees have been used as one of representative classification algorithms. And they were normally used in the classification tasks that have label class values. However since using rule ranking methods, spatial prediction have been applied in the spatial prediction problems. This paper compared rule ranking methods for the spatial prediction application using a decision tree. For the comparison experiment, C4.5 decision tree algorithm, and rule ranking methods such as Laplace, M-estimate and m-branch were implemented. As a spatial prediction case study, landslide which is one of representative spatial event occurs in the natural environment was applied. Among the rule ranking methods, in the results of accuracy evaluation, m-branch showed the better accuracy than other methods. However in case of m-brach and M-estimate required additional time-consuming procedure for searching optimal parameter values. Thus according to the application areas, the methods can be selectively used. The spatial prediction using a decision tree can be used not only for spatial predictions, but also for causal analysis in the specific event occurrence location.

• Journal of Korea Port Economic Association
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• v.29 no.2
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• pp.81-111
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• 2013

Along with a general growth in living standards there has been a corresponding increase in the demand for tourism. Cruise based tourism, in particular, has become one of the most dynamic and dramatic growth sectors in the tourism industry over the last 20 years, including in the Northeast Asian region. In line with the growth of passenger numbers, the number of cruise ships and their berth capacities has increased significantly since the late 1970s. Korea, as a peninsular nation, has also experienced a rapid growth in cruise passenger numbers. The national economy has greatly benefited from this as the industry acts as an income generator, creating new jobs and potential investments and in developing local tourism. Ports play an important role in the development of any national cruise industry, providing not only ship berths but supply and bunkering facilities and a gateway to local tourism opportunities. The selection of the optimal cruise port location is an important and complex problem because the decision makers have to consider a large number of criteria which have a significant effect on the economy, environment, human life, and society. This paper investigates those criteria that are significant in developing a successful cruise port by employing a questionnaire survey of major cruise port users - shipping companies and tourism companies. The ports, surveyed in this study are Busan, Incheon, Yeosu and Jeju. All have been identified as important potential cruise ports in the Korean Government's 'The 3rd Port Basic Plan (2011-2020)'.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.304-317
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• 2020

This study conducted selected two sites in Geumnamhonam and four sites in Honam-Jeongmaek for vegetation survey with consideration to the location environment and anthropogenic impacts to investigate the vegetation structures of the Geumnamhonam-Jeongmaek·Honam-Jeongmaek ridge areas. Using TWINSPAN (two-way indicator species analysis), each of the two ridge areas were categorized into seven plant communities. The differential species in the TWINSPAN technique indirectly represent the environmental factors of plant communities, and the community types of the two ridge areas were divided based on environmental factors such as altitudes above sea level, soil moisture, and disturbance. These results were in harmony with the environmental factors of the DCA (detrended correspondence analysis) axis 1. In the low-lying areas of both ridge areas, afforestation tree species such as Pinus rigida and P. thunbergii were in competition with native tree species. As such, in the low-lying areas, artificial vegetation disturbance was severe due to afforestation and development projects. In relatively highland areas, such as upper slopes, and top areas, in the ridge, the vegetation type with the dominance of Quercus mongolica, Q. variabilis, and P. densiflora was preserved well. As for differences between the two ridge areas, communities dominated by Q. mongolica were distributed widely in Geumnamhonam-Jeongmaek because of the altitudes above sea level, and the latitude of this ridge area are higher than those of Honam-Jeongmaek. On the other hand, communities dominated by P. densiflora were distributed along with communities dominated by Q. mongolica, and communities dominated by Q. variabilis appeared in Honam-Jeongmaek because it is adjacent to the south coast. In quantitative vegetation analysis such as TWINSPAN and DCA, changes in species composition and the extracting environmental factors that cause the changes are important. To that end, the removal of accidental emergent species, the establishment of an investigation plan that assumes environmental factors, and the selection of the optimal analytical method suitable for the characteristics of the survey data are necessary.

• Geophysics and Geophysical Exploration
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• v.18 no.3
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• pp.154-161
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• 2015

For efficiently designing neutron induced gamma spectroscopy sonde, Monte Carlo simulation is employed to understand a dominant location of thermal neutron and classify the formation elements from the energy peak of capture gamma spectrum. A pulsed neutron generator emitting 14 MeV neutron particles was used as a source, and flux of thermal neutron was calculated from the twelve detectors arranged at each 10 cm intervals from the source. Design for reducing borehole effects using shielding materials was also applied to numerical sonde model. Moreover, principal elements and quantities of numerical earth models were verified through the energy spectrum analysis of capture gamma detected from a gamma detector. These results can help to enhance the signal-to-noise ratio, and determine an optimal placement of capture gamma detectors of neutron induced gamma spectroscopy sonde.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.2
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• pp.149-162
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• 2005

This paper suggest a way to detect a specific wanted figure in public places such as subway stations and banks by comparing color face images extracted from the real time CCTV with the face images of designated specific figures. Assuming that the characteristic of the surveillance camera allows the face information in screens to change arbitrarily and to contain information on numerous faces, the accurate detection of the face area was focused. To solve this problem, the normalization work using subsampling with $20{\times}20$ pixels on arbitrary face images, which is based on the Perceptron Neural Network model suggested by R. Rosenblatt, created the effect of recogning the whole face. The optimal linear filter and the histogram shaper technique were employed to minimize the outside interference such as lightings and light. The addition operation of the egg-shaped masks was added to the pre-treatment process to minimize unnecessary work. The images finished with the pre-treatment process were divided into three reception fields and the information on the specific location of eyes, nose, and mouths was determined through the neural network. Furthermore, the precision of results was improved by constructing the three single-set network system with different initial values in a row.