• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.515-523
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• 2015

This study reviewed 612 DP LOP(Loss of Position) incident reports which submitted to IMCA from 2001~2010 and identified 103 human error caused incidents and classified it through HFACS. And, this study analysis of conditional probability of human error on DP LOP incidents through application of bayesian network. As a result, all 103 human error related DP LOP incidents were caused by unsafe acts, and among unsafe acts 70 incidents(68.0 %) were related to skill based error which are the largest proportion of human error causes. Among skill based error, 60(58.3%) incidents were involved inadvertent use of controls and 8(7.8%) incidents were involved omitted step in procedure. Also, 21(20.8%) incidents were involved improper maneuver because of decision error. Also this study identified that unsafe supervision(68%) is effected as the largest latent causes of unsafe acts through application to bayesian network. As a results, it is identified that combined analysis of HFACS and bayesian network are useful tool for human error analysis. Based on these results, this study suggest 9 recommendations such as polices, interpersonal interaction, training etc. to prevent and mitigate human errors during DP operations.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.353-360
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• 2007

We practiced fresh water injection test to identify its applibility as a method of seawater intrusion mitigation technique, and monitored the change of borehole fluid conductivity and the behavior of injected fresh water using borehole multichannel electrical conductivity monitoring and well-logging, and DC resistivity and SP monitoring at the surface. Well-logging and multichannel EC monitoring showed the decrease of fluid conductivity due to fresh water injection. We note that such an injection effect lasts more than several month which means the applibility of fresh water injection as a seawater intrusion control technique. Although SP monitoring did not show meaningful results because of weather condition during monitoring and the defects of electrodes due to long operation time, DC resistivity monitoring showed its effectiveness and applicability as a monitoring and assessment techniques of injection test by means of imaging the behavior and the front of fresh water body in terms of the increase of resistivity with reasonable resolution. In conclusion, we note that geophysical techniques can be an effective method of monitoring and evaluation of fresh water injection test, and expect that fresh water injection may be an practical method for the mitigation of seawater intrusion when applied with optimal design of injection well distribution and injection rate based on geophysical evaluation.

• Journal of Acupuncture Research
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• v.25 no.4
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• pp.81-94
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• 2008

Rheumatoid arthritis(RA) is a general, chronic, inflammatory and auto-immune disease and it can lead to joint edema, pain, stiffness which are caused by an inflammation in synovium covering our joints. Ulmus davidiana Planchon is a traditional herb used for the treatment on various inflammations, gastrointestinal trouble, ENT(ear, nose, and throat) disease, edema, cancer etc. and it works effectively on arthritis as well. In these study to search for the treatment efficacy of Ulmus davidiana Planchon in RA, I measure manifestation of cytokine gene in synoviocyte treated with Ulmus davidiana Planchon herbal acupuncture and in EL-4 cell, manifestation of cytokine gene cell related to T-cell. And after Ulmus davidiana Planchon herbal acupuncture treatment in Collagen induced arthritis(CIA) which has been known by a general model of RA, DBA mice, I observed foot thickness, general shape of synovium, early cytokine induce CIA and, generation and mutation of cytokine related to the control of T-cell specialization. It comes to conclusion as belows. 1. In synovium treated with Ulmus davidiana Planchon herbal acupuncture, there was the decrease in MIF mRNA does-dependently. Incase of CIA mice treated with Ulmus davidiana Planchon herbal acupuncture, there were the decrease in the damage in synovium and generation of the MIF which is related to induction of the early RA cytokine and IL-6 proinflammatory cytokine. 2. In case of EL-4 treated with Ulmus davidiana Planchon herbal acupuncture, there were decrease in the manifestation of the IL-2 mRNA, but the increase in the manifestation of the IL-4 does-dependently. 3. In the synovium of CIA mice treated with Ulmus davidiana Planchon herbal acupuncture, there were the decrease in generation of IL-2, IL-12 and CD-28, but the increase in generation of IL-4. These result suggest that Ulmus davidiana Planchon can block the process of the early RA by Inhibiting MIF activation, and mitigate Rheumatoid Arthritis by controlling Tcell specialization.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.65-71
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• 2017

Digital images and videos are subject to various types of noise during storage and transmission. Among these noises, Salt & Pepper noise degrades the compression efficiency of the original data and causing deterioration of performance in edge detection or segmentation used in an image processing method. In order to mitigate this noise, there are many filters such as Median Filter, Weighted Median Filter, Center Weighted Median Filter, Switching Weighted Median Filter and Adaptive Median Filter. However these methods are inferior in performance at high noise density. In this paper we propose a new type of filter for noise mitigation in wireless communication environment where Salt & Pepper noise occurs. The proposed filter detects the location of the damaged pixel by Salt & Pepper noise detection and mitigates the noise by using adjacent pixel values which are not damaged in a certain area. Among the proposed filters, the performance of the filter using the $3{\times}3$ error mask is compared with that of the conventional methods and it is confirmed that when density of noise in the image is 95%, their performances are improved as 13.24 dB compared to MF and 13.09 dB compared to AMF.

• Management & Information Systems Review
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• v.32 no.1
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• pp.259-272
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• 2013

This Paper document that managers' cash compensation is more sensitive to negative stock return than positive stock return. Also, this paper analyse that managers' cash compensation react symmetrically to accounting earnings and losses. Since stock returns include both unrealized gains and unrealized losses, we expect managers' cash compensation to be less sensitive to stock returns when returns contain unrealized gains(positive returns) than when returns contain unrealized losses(negative returns). But accounting earnings exclude unrealized gains and include unrealized losses, so managers' cash compensation will react symmetrically to accounting earnings and losses. Analyzing 5,815 firm-year data for 2000-2011, we find that managers' cash compensation reacts asymmetrically to stock retruns whereas managers' cash compensation reacts symmetrically to accounting performance. This finding is consistent with boards of directors seeking to mitigate ex post settling up problem that would arise of managers' cash compensation was equally sensitive to positive and negative stock return.

• Journal of Korea Port Economic Association
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• v.27 no.4
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• pp.187-205
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• 2011

In considering the size of container logistic flow of Korea, one-port as a hub port is desirable in Busan Port, but as development of Busan Port and Gwangyang Port began as two-ports, they are good as mega hub ports. In case when ports of other regions such as Incheon Port are additionally developed, it is very likely that they become feeder ports rather than mega hub ports. As capital area uses Incheon Port and Pyeongtaek Port for transportation, fierce competition arises due to excessive facilities of terminal companies and it is not easy to be profitable. Therefore, it is more profitable to develop regional hub ports centering on near-sea routes of Korea China Japan rather than local ports such as Incheon Port and Pyeongtaek Port for intensive trade and transportation in the capital area. To mitigate excessive competition between container terminal companies, we need administrative guidance to maintain adequacy through comparing tariffs between ports of Japan and China which are in competitive relations with Korean ports. This study analysed efficiency of container terminal companies in Gwangyang Port, Busan Port and Incheon Port using data for five years from 2006 to 2010. As analytical variables, length of quay, floor area of yard, the number of cranes and employees were analytical variables and a total freight volume was a productive factor.

• Journal of Korea Water Resources Association
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• v.48 no.2
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• pp.115-126
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• 2015

In recent years, debris flow disaster has occurred in multiple locations between high and low mountainous areas simultaneously with a flooding disaster in urban areas caused by heavy and torrential rainfall due to the changing global climate and environment. As a result, these disasters frequently lead to large-scale destruction of infrastructures or individual properties and cause psychological harm or human death. In order to mitigate these disasters more effectively, it is necessary to investigate what causes the damage with an integrated model of both disasters at once. The objectives of this study are to analyze the mechanism of debris flow for real basin, to determine the PMP and run-off discharge due to the DAD analysis, and to estimate the influence range of debris flow for fan area according to the scenario. To analyse the characteristics of debris flow at the real basin, the parameters such as the deposition pattern, deposit thickness, approaching velocity, occurrence of sediment volume and travel length are estimated from DAD analysis. As a results, the peak time precipitation is estimated by 135 mm/hr as torrential rainfall and maximum total amount of rainfall is estimated by 544 mm as typhoon related rainfall.

• International Journal of Railway
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• v.2 no.3
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• pp.124-126
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• 2009

Energy savings can be achieved with optimum energy consumptions, brake energy regeneration, efficient energy storage (onboard, line side), and primarily with light weight vehicles. Over the last few years, the rolling stock industry has experienced a marked increase in eco-awareness and needs for lower life cycle energy consumption costs. For rolling stock vehicle designers and engineers, weight has always been a critical design parameter. It is often specified directly or indirectly as contractual requirements. These requirements are usually expressed in terms of specified axle load limits, braking deceleration levels and/or demands for optimum energy consumptions. The contractual requirements for lower weights are becoming increasingly more stringent. Light weight vehicles with optimized strength to weight ratios are achievable through proven design processes. The primary driving processes consist of: $\bullet$ material selection to best contribute to the intended functionality and performance $\bullet$ design and design optimization to secure the intended functionality and performance $\bullet$ weight control processes to deliver the intended functionality and performance Aluminium has become the material of choice for modern light weight bodyshells. Steel sub-structures and in particular high strength steels are also used where high strength - high elongation characteristics out way the use of aluminium. With the improved characteristics and responses of composites against tire and smoke, small and large composite materials made components are also found in greater quantities in today's railway vehicles. Full scale hybrid composite rolling stock vehicles are being developed and tested. While an "overdesigned" bodyshell may be deemed as acceptable from a structural point of view, it can, in reality, be a weight saving missed opportunity. The conventional pass/fail structural criteria and existing passenger payload definitions promote conservative designs but they do not necessarily imply optimum lightweight designs. The weight to strength design optimization should be a fundamental design driving factor rather than a feeble post design activity. It should be more than a belated attempt to mitigate against contractual weight penalties. The weight control process must be rigorous, responsible, with achievable goals and above all must be integral to the design process. It should not be a mere tabulation of weights for the sole-purpose of predicting the axle loads and wheel balances compliance. The present paper explores and discusses the topics quoted above with a view to strengthen the recommendations and needs for the weight optimization by design approach as a pro-active design activity for the rolling stock industry at large.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.4
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• pp.431-439
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• 2010

Cross-interferometic synthetic aperture radar (CInSAR) technique from ERS-2 and Envisat images is capable of generating submeter-accuracy digital elevation model (DEM). However, it is very difficult to produce high-quality CInSAR-derived DEM due to the difference in the azimuth and range pixel size between ERS-2 and Envisat images as well as the small height ambiguity of CInSAR interferogram. In this study, we have proposed an efficient method to overcome the problems, produced a high-quality DEM over northern Alaska, and compared the CInSAR-derived DEM with the national elevation dataset (NED) DEM from U.S. Geological Survey. In the proposed method, azimuth common band filtering is applied in the radar raw data processing to mitigate the mis-registation due to the difference in the azimuth and range pixel size, and differential SAR interferogram (DInSAR) is used for reducing the unwrapping error occurred by the high fringe rate of CInSAR interferogram. Using the CInSAR DEM, we have identified and corrected man-made artifacts in the NED DEM. The wave number analysis further confirms that the CInSAR DEM has valid Signal in the high frequency of more than 0.08 radians/m (about 40m) while the NED DEM does not. Our results indicate that the CInSAR DEM is superior to the NED DEM in terms of both height precision and ground resolution.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.305-316
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• 2018

As the urbanization ratio increases, the heat environment in cities is becoming more important due to the urban heat island. In this study, the heat island spatial analysis was calculated and conducted for analysis of urban thermal environment of Sejong city, which was launched in 2012 and has been developed rapidly. To analyze the ratio and change rate of urban area, a multi temporal land cover map (2013 to 2015 and 2017) of study area is generated based on Landsat-8 OLI/TIRS (Operational Land Imager / Thermal Infrared Sensor) satellite imagery. Then, we select an TIR (Thermal Infrared) band from the two TIR bands provided by the Landsat-8, which is used for calculating the heat island potential, through the accuracy evaluation of the brightness temperature and AWS (Automatic Weathering Station) data. Based on the selected band and surface emissivity, land surface temperature is calculated and the estimated heat island potential change is analyzed. As a result, the land surface temperature of the high ratio and change rate of urban area was significantly higher than the surrounding area around $3^{\circ}C$ to $4^{\circ}C$, and the heat island potential was also higher around $4^{\circ}C$ to $5^{\circ}C$. However, the heat island phenomenon was alleviated in urban areas with high rate of change that also show high green area ratio. Therefore, we demonstrated that dense urban area increases the possibility of inducing heat island, but it can mitigate the heat island through green areas.