• Korean Journal of Environment and Ecology
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• v.35 no.2
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• pp.181-192
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• 2021

This study surveyed visitors' perceptions of Mudeungsan National Park's Seoseokdae Trail Section (STS) on the visitor reservation system (VRS). Data were collected from 248 visitors to STS selected through convenient sampling in May 2019. The majority (86.9%) of the respondents rated their overall experience in STS as either "no problem at all" or "little problem". Moreover, 43.0% of the respondents were aware of the VRS. The most popular information source for VRS was the Internet (49.7%), followed by other people (18.4%) and broadcasting media, e.g., TV (17.7%). While 69.9% of the respondents thought that implementation of VRS would be effective in improving managerial conditions of the STS, respondents perceived that "cumbersome reservation procedures" (79.3%) of the VRS operation was the most important problem, followed by "unfairness associated with Internet familiarity gap" (78.7%) and "deprivation of the opportunities to visit freely" (76.3%). The support for VRS implementation was higher among higher-aged, married, higher-educated, more frequent STS visitors, Gwangju residents, and solo visitors than the other groups. The "knowledge level about VRS" and "the awareness level about potential problems associated with VRS operation" negatively influenced the support for the implementation of VRS, while "the perceived managerial effectiveness of VRS" positively influenced it.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.61-68
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• 2008

The effect of rupture on the speed of ultrasonic wave was investigated with the PUNDIT and the effective detecting method of defects, moving transmitter and receiver. The speed of ultrasonic wave according to the course of rupture was not affected by transmitter and receiver and in the course of parallel rupture, but only in the course of vertical rupture. When rupture was not located on the ultrasonic wave progressing course, rupture was not detected. However, if rupture was formed perpendicularly to the ultrasonic wave progressing course but located on the ultrasonic wave progressing direction, rupture can be detected. Also, the rupture can be detected, when one transmitter and receiver was placed at top and the other at bottom. After detecting rupture in a part, rupture was determined accurately, placing and moving two transmitters and receivers at width.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.5
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• pp.383-390
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• 2008

The SCR in Static Transfer Switch (STS) is used for reliability improvement of important load's power supply in industry field. However an average of 2% fault in thyristor(SCR) occurs, so that the attached mechanical switch is paralleled with SCR's both end points and SCR operates only during the $12{\sim}208$[mS] before operation of the mechanical switch. Also, an ISC (Ideal State Conditioning Interlock Device) - STS system that two power supply paths may not be thrown at the same time is developed to remove the overlap section perfectly when a short or earth fault is generated in one system. This method has reduced the fault rate remarkably through the reduction of SCR's fatigue degree by using SCR in conversion operation corresponding to 0.89 times a year. Also, in case of fault generations, it does not affect to supply power to the load, therefore it contributes to the promotion of reliability in the power supply.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.95-103
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• 2015

This paper presents the effects of the tool shape on the geometrical characteristics of flat end-milled side walls. A tool shape is characterized by such parameters as helix angle, number of cutting edges, and diameter. The geometrical characteristics of the side walls are represented by the surface profiles in the feed and axial directions, which are orthogonal to each other. The geometrical defects in each direction are estimated based on the instantaneous apparent cutting areas, which are represented by the interference area between the tool and workpiece and that between the cutting edge and workpiece. It is confirmed that a geometrical defect in the feed direction is formed when the tool leaves the workpiece and the curvature of the tool path changes. Defects in the axial direction are also found in the side walls, except for the defect zone in the feed direction. An up-cut using an end-mill with a steeper helix angle, a greater number of cutting edges, and a smaller diameter are thus found to improve the geometrical accuracy of end-milled side walls.

• Tunnel and Underground Space
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• v.25 no.4
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• pp.373-382
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• 2015

This study presents a method to calculate carbon dioxide emissions of diesel vehicles operated in an underground mine using Geographic Information Systems (GIS). An underground limestone mine in Korea was selected as the study area. A GIS database was constructed to represent the haulage roads as a 3D vector network. The speed of dump trucks at each haulage road was investigated to determine the carbon dioxide emission factor. The amount of carbon dioxide emissions related to the truck's haulage work could be calculated by considering the carbon dioxide emission factor at each haulage road and the haulage distance determined by GIS-based optimal route analysis. Because diesel vehicles are widely utilized in the mining industry, the method proposed in this study can be used and further improved to calculate the amount of carbon dioxide emissions in mining sites.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5A
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• pp.267-275
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• 2003

In UMTS terminal modem uses 3 step search procedure for initial cell search, which comprises 1) slot synchronization, 2) code group identification and frame synchronization, and 3) scrambling-code identification. The performance of initial cell search procedure depends on search parameters like observation time and threshold. The purpose of this paper is to get the optimal observation time and threshold of each step for minimum mean acquisition time. In this paper we induce mean detection time of each step and mean acquisition timefrom the model of 3 step search procedure using state diagram. Also we propose initial cell search algorithm which utilize window search method against initial oscillator error, and select an appropriate observation time and threshold of each step by the analysis of simulation and induced result. It is shown that the mean acquisition time in multipath fading channel can be shorter than 500ms by using the determined observation time and threshold of each step.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.129-138
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• 2011

This research has proposed a quantitative environmental assessment method of road routes based on the various policies and literature, and applied such proposal to the planned road routes to evaluate the environment-friendly road routes. Accordingly, the case sections per each region of Joong-bu, Gang-won, and Nam-bu were selected to execute the proposed environmental assessment method. Consequently, it has been confirmed that the distribution of environmental score of the subject region of each case section varied. In particular, for the Gang-won region, the high scores took up the most. Also, to indicate the degree of environment per each section, a route which minimizes the environmental effects per subject region was created to analyze the environmental degree per each section. As a result, the section in the region with the highest environmental sensitivity, in other words the Gang-won region with many high scores, had the lowest environmental degree.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.45-52
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• 2004

This Paper presents a modified hard decision Viterbi decoder with an error prediction circuit enhancing performance for the burst error inputs. Viterbi decoder employs the maximum likelihood decoding algorithm which shows excellent error correction capability for the random error inputs. Viterbi decoders, however, suffer poor error correction performance for the burst error inputs under the fading channel. The proposed error prediction algorithm increases error correction capability for the burst errors. The algorithm estimaties the burst error data area using the maximum path metric for the erroneous inputs, It calculates burst error intervals based on increases in the maximum values of a path metric. The proposed decoder keeps a performance the same as the conventional decoders on AWGN channels for the IEEE802.l1a WLAN system. It shows performance inproving 15% on the burst error of multi-path fading channels, widely used in mobile systems.

• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.19-28
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• 2013

The longitudinal axial strain in the plastic hinge region of reinforced concrete (RC) columns influences on the structural behavior of RC structures subjected to reversed cyclic loading. This strain decreases the effective compressive strength of concrete and increases the lateral displacements between stories by causing the elongation of member length. This paper investigated the effects of the axial force on the elongation of a RC member by using a sectional analysis of RC members. The analytical and experimental results indicated that the axial force decreased the axial strain in the plastic hinge region of RC columns. In this study, a model was proposed to predict the axial strain of RC columns. The proposed model considering the effects of axial force ratio consisted of three path types ; Path 1-loading region, Path 2-unloading region, and Path 3-reversing cyclic loading region. The axal strains predicted by the proposed model were compared with the test results of RC columns with various axial force ratios, and agreed reasonably with the observed longitudinal strains.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.4
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• pp.87-93
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• 2009

The increased person interests in health in accordance with improved living standards result in the booming population who enjoy mountain climbing. Although there are more climbers than ever, most existing mountain paths are those which have been made naturally by people utilizing them to get to the peak and therefore cannot meet the various needs of emerging mountain climbers. Thus, this study that establish a data using numerical map and TotalStation aimed to provide them with beneficial information on mountain paths, analyzing each path using GIS. The subjects of this study are limited to Kum-Am which is in Kyungnam province, Korea. According to out research, proper slopes for the majority of mountain climbers, mostly in their from 30s to 50s, are turned out to be HG1 and JG1-JG2-JG3.