• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.4
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• pp.78-86
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• 2011

The recovering of historical mountain fortress needs the maintenance of forest scape for achieving visibility. In the study, the methods for the maintenance of the forest around the fortress were proposed. The Cumulative Visibility Analysis and Multiple Sight Surface Analysis were tested to verify the methods using GIS on the Myeong-hwal Fortress in Kyungju. The results of the study are as follows. First, the Cumulative Visibility Analysis was made on the Myeong-hwal Fortress from surrounding major viewpoints. The Cumulative Visibility Analysis enables the selection of excellent visibility sectors on the fortress. The 6 excellent visibility sectors were 1,937m(which occupied 41.2% of the area). Second, two cases of pine tree height were compared in the Cumulative Visibility Analysis. One used the average height of pines and the other used the maximum growth height. The comparative result demonstrated that the case of average height would be more effective for deciding the pine removal zone as well as achieving visibility to the mountain fortress. Third, to examine the feasibility of the management method, the tree removal plan and removal execution were compared on the A zone which showed high visibility frequency. Asa comparative result, there was insignificant difference(3.3%) in area between the tree removal plan($10,935m^2$) and removal execution($11,296m^2$). This study proved the Cumulative Visibility Analysis and Multiple Sight Surface Analysis to be effective for forest scape maintenance around a mountain fortress.

• Journal of the Ergonomics Society of Korea
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• v.22 no.1
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• pp.81-94
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• 2003

The British railway safety research group has developed a risk assessment model for the railway infrastructure and major railway accidents. The major hazardous factors of the railway infrastructure were identified and classified in the model. The frequency rates of critical top events were predicted by the fault tree analysis method using failure data of the railway system components and ratings of railway maintenance experts, The consequences of critical top events were predicted by the event tree analysis method. They classified the Joss of accident due to railway system into personal. commercial and environmental damages. They also classified 110 hazardous event due to railway system into three categories. train accident. movement accident and non-movement accident. The risk assessment model of the British railway system has been designed to take full account of both the high frequency low consequence type events (events occurring routinely for which there is significant quantity of recorded data) and the low frequency high consequence events (events occurring rarely for which there is little recorded data). The results for each hazardous event were presented in terms of the frequency of occurrence (number of events/year) and the risk (number of equivalent fatalities per year).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10B
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• pp.876-890
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• 2003

This paper proposes a protocol for the reliableand QoS-aware multicast transport, which is called the Enhanced Communications Transport Protocol (ECTP). The ECTP has so far been developed and standardized in ITU-T SG17 and ISO/IEC JTC 1/SC 6. Differently from the conventional reliable multicast, as shownin the IETF RMT WG, the ECTP additionally provides several distinct features such as tight control of multicast session, tree-based error control, and QoS management. For the tight control of multicast connections, the sender is at the heart of one-to-many group communications, and it is responsible for overall connection management such as connection creation/termination, pause/resumption, and the join and leave operations. for tree-based reliability control, ECTP configures a hierarchical tree during connection creation. Error control is performed within each local group defined by a control tree, which was partly designed like the IETF TRACK approach. Each parent retransmits lost data in response to retransmission requests from its children. For QoS management, ECTP supports QoS negotiation for resource reservation, and it also provides QoS monitoring and maintenance operations. ECTP has been implemented and tested on Linux machine, along with Application Programming Interfaces based on Berkeley sockets. For basic testing of the ECTP functionality, we give some preliminary experimental results for performance comparison of ECTP and TCP unicast transports. In conclusion, we describe the status of ECTP experimentations over APAN/KOREN testbed networks

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.655-662
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• 2010

Desertification has been expanding with a remarkable speed across the Northeast Asia. Desertification in Northeast Asia significantly influences Korea's economy and environmental health conditions in recent years. For these reasons, a number of non-governmental organizations (NGOs) in Korea have carried out the reforestation projects to combat desertification in China and Mongolia. Several tree plantation projects were implemented in Mongolia and China. The objective of this study was to analyze and evaluate the performance of tree plantation aid projects carried out by Korean NGOs in Mongolia. The performance of tree plantation projects was examined through effectiveness, efficiency, equity and responsiveness of those projects. The performance was analyzed with the survival rate of planted trees and planting cost, the recognitions of Mongolian people. The analysis of the performance showed that the tree plantation cooperation projects carried out by Korean NGOs in Mongolia had comparatively high performance from a larger point of view. Especially, effectiveness and responsiveness of their projects were highly marked in spite of all the difficulties of carrying out the tree plantation. Such a high effectiveness represented the relatively higher survival rates of trees and Mongolian's positive recognition of plantation projects. Furthermore, the responsiveness also turned out to be high with a great satisfaction of the Mongolian people for plantation projects conducted by the Korean NGOs. Survey results indicated that the efficiency and equity of the projects would be increased by promoting the cooperation projects for tree planting throughout Mongolia with reinforcing infrastructures. By comparison between Korean NGOs and Mongolian Government plantation projects, confirmed the importance of sustained financial support and maintenance activities in the plantation sites.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.57-64
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• 2007

One of the cause of insulation failure in power cable is well known by electrical treeing discharge. This is occurred for imposed continuous stress at cable. And this event is related to safety, reliability and maintenance. In this paper, throughout analysis of partial discharge(PD) distribution when occurring the electrical tree, is studied for the purpose of knowing of electrical treeing discharge characteristics according to defects. Own characteristic of tree will be differently processed in each defect and this reason is the first purpose of this paper. To acquire PD data, three defective tree models were made. And their own data is shown by the phase-resolved partial discharge method (PRPD). As a result of PRPD, tree discharge sources have their own characteristics. And if other defects (void, metal particle) exist internal power cable then their characteristics are shown very different. This result Is related to the time of breakdown and this is importance of cable diagnosis. And classification method of PD sources was studied in this paper. It needs select the most useful method to apply PD data classification one of the proposed method. To meet the requirement, we select methods of different type. That is, neural network(NN-BP), adaptive neuro-fuzzy inference system and PCA-LDA were applied to result. As a result of, ANFIS shows the highest rate which value is 98 %. Generally, PCA-LDA and ANFIS are better than BP. Finally, we performed classification of tree progress using ANFIS and that result is 92 %.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.119-130
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• 2012

In this paper, we propose ubiquitous tree management system based on GIS and smart-phone using the object-oriented design modeling to maximize the efficiency of tree management. For this, proposed system is implemented in the form of client/server (C/S). The spot tree management system as the client is based on the mobile(PDA, Smart-Phone), whereas the tree management system based on PC as the server makes use of GIS. Also, Web service method instead of CDMA used in exist studies is used for tree data communication among C/S. And problems of existing studies, that is excessive maintenance costs, accessibility shortage of variety users, connectivity shortage of geographic information system will be settled through the convergence of the proposed system development methods, GIS system, smart devices. Therefore, we verify proposed system by using the systemic unit test and qualitative assessment respectively and prove to be more excellent than the existing system based on the mobile, in terms of systemic effectiveness and extendability.

• Journal of Agricultural Extension & Community Development
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• v.30 no.2
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• pp.119-129
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• 2023

This study aims to identify the types of safety accidents that occur during maintenance and repair operations and analyze the root causes. We used the logic tree diagramming to extract the root causes of 65 safety incidents specifically related to maintenance and repair work out of a total of 1,024 agricultural safety incidents that occurred between 2007 and 2020 collected by investigation with interviews. The extracted root causes were analyzed by categorizing them into six different safety system classifications. The results of the analysis and suggestions are as follows. Incidents related to maintenance and repair work, which can lead to irreversible safety hazards, have occurred frequently. These incidents were found to be occurring due to the overlapping of various safety system errors such as personal protective system and safety operation procedure. In the short term, it is necessary to emphasize compliance with the use of personal protective equipment, and enhancement of maintenance training. In the long term, it is necessary to establish a legal distinction for maintenance and repair work and clarify the responsible parties. Introducing a maintenance system is also crucial to prevent occupational injuries during maintenance and repair in agriculture.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.3
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• pp.45-54
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• 2012

This study intended to analyze growth condition of each object by protected tree's ground for 45 places registered to Pyeongtaek protected tree list in locational characteristics, conduct exchange analysis for impediment extent rate in crown area and tree type to the result and suggest the measures to manage artificial impediment which is an effect on protected tree condition. In this study, the tree whose area of impediment for crown area is less than 21% is tree condition of grade 1~2, less than 21~50% is grade 2~3 and more than 50% is grade 3~5. The more impediment is, the more inconvenience causes on growth and development. So, it verified that the area rate must maintain less than 21% for the root system management of protected tree. For the standard of managing artificial impediment which is an effect on the tree condition of protected trees, the below matters intend to be suggested. The first, the impediment in crown area should be less than 21%. But, if there is not artificial impediment out of crown area, the rate of impediment area is considered to increase somewhat. The second, growth space of protected tree should be maintained by crown area at least and impediment should be established out of the crown area. The third, during the national project and land development, surroundings of protected tree must be applied as park, resting place, etc. and the establishment area of impediment (artificial impediment and natural impediment) in crown area must be limited. The forth, publicity for regional people (especially, land owner) is necessary for the protection of natural inheritance and the value of dependence on local government and village which are the subject of management must be announced widely through the internet media, etc, so its importance must be recognized. The fifth, the matters related to protected tree management must be able to limit artificial damage which is for surroundings of protected tree through the mutual connection among the local governments; construction, civil engineering, architecture, water and sewage, agriculture and forest and others. Also, following studies on the effects of kinds, thickness, etc. of impediment around the protected tree on trees should be continued.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.131-140
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• 2004

It really needs fuzzy decision making of integrity assessment considering about both durability and load carrying capacity for maintenance and administration, such as repairing and reinforcing. This thesis shows efficient models about reinforced concrete structure using CART-ANFIS. It compares and analyzes decision trees parts of expert system, using the theory of fuzzy, and applying damage & diagnosis at reinforced concrete structure and decision trees of integrity assessment using established artificial neural. Decided the theory of reinforcement design for recovery of durability at damaged concrete ＆ the theory of reinforcement design for increasing load carrying capacity keep stability of damage and detection. It is more efficient maintenance and administration at reinforced concrete for using integrity assessment model of this study and can carry out predicting cost of life cycle.

• Journal of Korean Society of Rural Planning
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• v.17 no.2
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• pp.23-32
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• 2011

The purpose of this study is to produce basic planning criteria required in ecological restoration and improvement works of streams in rural area through the application of stream assessment methods (water quality, soil environment, and ecological function assessment) at 6 study sites of Han River basin. The investigation results were as followings; 1) There were the evaluation items like a manure use, salt degree, river peripheral tree, which did not fitted to apply to domestic streams, in the SVAP (Stream Visual Assessment Protocol) and NRCS Riparian Assessment that were evaluation models developed in USDA. The area inhabitants with a little knowledge and education personally seems to utilize the evaluation methods through improvement partly with an aspect that evaluation is slightly easy. 2) From the stream assessment results, the construction of diverse pools, large woody debris and isolated backwater pool are needed to improve a few of problems observed at the mostly study sites. The result of NRCS Riparian Assessment showed that the improvement of stream bank vegetative communities is needed by planting tree with deep-binding root masses, and managing of noxious weeds and exotic undesirable plants. 3) Summing up, the assessment results showed that the assessment scores were higher at upstream than downstream, the stream with totally maintenance than that with partly maintenance, the stream with slope bank than that with vertical bank, and the stream with a flood plain than that without a flood plain. So, the direction of stream maintenance projects must be set by consideration of those results.