• Journal of the Korean GEO-environmental Society
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• v.15 no.7
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• pp.59-66
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• 2014

Nowadays, some studies are performed in order to introduce the Limit State Design method widely used in foreign work sites. LRFD (Load Resistance Factor Design) method is widely used in the fields in which the data accumulation is possible - such as deep foundations, and shallow foundations, etc. The limit state design in the retaining walls is insufficient in the country owing to difficulties applying load tests. The limit state design method for retaining wall structures are studied based upon the National Retaining wall Design Standard legislated in 2008 by Ministry of Land, Transport, and Maritime Affairs. In this paper several retaining walls were calculated according to LRFD design criteria analysis using the general program with limit state design method and the factor of safety for sliding and overturning. Comparing with their results, the Taylor's series simple reliability analysis was performed. In the analysis results of retaining wall section, safety factors calculated by LRFD were found to be lowered than those calculated in current WSD, and it is possibly judged to be economic design by changing wall dimensions. In the future, pre-assessment of the geotechnical data for ensuring the reliability and the studies including reinforced retaining walls with ground anchor are needed.

• Journal of Korea Port Economic Association
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• v.32 no.4
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• pp.127-147
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• 2016

This study proposes the improvement scheme of the current lease rate assessment system (2003~2014), as a major problem solving area, for the Terminal Operating Company (TOC)'s wharf since the introduction of the TOC system in 1997. The study considers the reform system using three criteria: standardization, simplification, and fairness. The final alternative presented by the study adopts the lease rate assessment system, which newly reflects changes of facilities' property values for aprons, combining it with the related fees of the Korean seaport dues for open storage yards, warehouses (shed), passages, buildings and lands within leased facilities. The proposal anticipates that the new system will not only minimize stakeholders' confusion, but also resolve the main problems within the current system. The study, further, introduces the adjustment ratio, which will make the new lease rate of the apron equal to the current lease rate of a berth, for the individual TOC's wharf, in order to prevent a sharp increment in the lease rate of the apron. This is because the government or port authorities as lessors, need to give priority to lightening the burden of TOC's costs under the deteriorating business environment such as the slowdown in port throughputs' growth. This study makes a contribution by suggesting a new lease rate assessment system for the TOC's wharf, reflecting the value of property as well as leading to its simplification and standardization. Additionally, it may lead to the improvement of fairness by applying the same rate to all leased wharfs for the lease rates of open storage yards, warehouses (shed) and passages. However, it has a limitation that hinders the fairness: the lease rate for the apron cannot be imposed in proportion to the leased area, by applying the individual adjustment ratios. In the future, those adjustment ratios should be, gradually, rationalized to be the same target ratio (0.5) for each wharf, following an improvement in the terminal operating business environment.

• Journal of Korea Water Resources Association
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• v.46 no.11
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• pp.1089-1101
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• 2013

The study uses a regional climate model to check future changes in extreme climate, to calculate extreme indexes presented by STARDEX, and to analyze the trends to predict the continuity and changes in the spatial distribution of extreme climate in the future. An analysis of extreme climate indices showed that they are likely to increase in the Seoul metropolitan area, in Gyeonggi-do, in Yongdong in Gangwon-do, and in the southern shore region of Korea. It is, however, forecasted to diminish in the central inland region. The analysis also showed that the average temperature in Korea will increase because of climate change. On the other hand, an analysis of extreme rainfall indexes showed that the trend of heavy rainfall threshold is 0.229 in Seogwipo, the greatest five-day rainfall is 5.692 in Seogwipo, and the longest dry period is 0.099 in Sokcho. Of extreme temperature indexes, the trend of Hotdays threshold is 0.777 in Incheon and the longest heat wave is 0.162 in Uljin. The Coldnight threshold is 0.075 in Inje and -0.193 in Tongyeong, according to the analysis.

• Journal of Korea Port Economic Association
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• v.26 no.2
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• pp.82-98
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• 2010

The purpose of this paper is to suggest the efficiency measurement way of Korean seaport by using Average Index Transformation model of fuzzy DEA(Data Envelopment Analysis). Two inputs[cargo handling capacity, and berthing capacity], and outputs[cargo handling amount, and the number of ship calls] are used in 1995 and 2004 for 26 Korean seaports. Empirical main results are as follows: First, Tongyung, Gohyun, Okpo, and Sogcho Ports are efficient, and Yeasu Port shows the high efficiency level over 95% under input oriented CCR model. Gohyun and Sogcho Ports showed the most efficient score under average index transformation model. Okpo and Yeasu Ports increased their efficiency scores as the lamda(λ) values are up. The empirical results of fuzzy DEA average index transformation model for Wando, Yeasu, and Seoguipo ports showed that if the lamda values are higher, the efficiency scores are also higher. The main policy implication based on the findings of this study is that the management manager of Ministry of Land, Transport and Maritime Affairs in Korea should introduce the fuzzy DEA average index transformation model for deciding the size of inputs including the port investment amount and evaluating the port efficiency.

• Journal of Korea Port Economic Association
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• v.26 no.4
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• pp.63-87
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• 2010

The purpose of this paper is to measure the efficiency of Korean container terminals by using SFA(Stochastic Frontier Analysis). Inputs[Number of Employee, Quay Length, Container Terminal Area, Number of Gantry Crane], and output[TEU] are used for 3 years(2002,2003, and 2004) for 8 Korean container terminals by applying both SFA and DEA models. Empirical main results are as follows: First, Null hypothesis that technical inefficiency is not existed is rejected and in the trasnslog model, the estimate is significant. Second, time-series models show the significant results. Third, average technical efficiency of Korean container terminals are 73.49% in Cobb-Douglas model, and 79.04% in translog model. Fourth, to enhance the technical efficiency, Korean container terminals should increase the handling amount of TEUs. Fifth, both SFA and DEA models have the high Spearman ranking of correlation coefficients(84.45%). The main policy implication based on the findings of this study is that the manager of port investment and management of Ministry of Land, Transport and Maritime Affairs in Korea should introduce the SFA with DEA models for measuring the efficiency of Korean ports and terminals.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.763-771
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• 2010

The rapid increase of wildlife passage installation since the late 2000s was aimed to reduce roadkill caused by habitat fragmentation and losses related to road construction, but wildlife-vehicle collisions are now still occurred even near the wildlife passage area. This is the reason that the effectiveness of wildlife passage have not been evaluated in combination with absence of monitoring data and management strategy of the wildlife passage. The AHP method are used, in this study, to identify the evaluation factors affecting the effectiveness of the present 367 wildlife passages in a mitigation measures to reduce road effects on wildlife species. Ten evaluation factors are derived from third levels in the AHP analysis. Priority setting to identify appropriate management strategies in first level is selected among four second levels on facility, environment, wildlife species and management tool. The AHP analysis suggested that neighboring environments are the most important factor at the second level, and passage structure, harmony with natural surroundings, wildlife occurrence and monitoring of the passage are also important factors at the third levels. In summary, effective measurements of wildlife passage management is based on managing the passage with neighboring topography and natural surrounding. This is useful to establish wildlife passage management strategy in order to reduce the negative effects of roads on wildlife species.

• Journal of Korea Water Resources Association
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• v.45 no.7
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• pp.657-674
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• 2012

This paper presents the effect of spatially-distributed rainfall on both rainfall-sediment-runoff and erosion or deposition in the experimental Cheoncheon catchment: upstream of Yongdam dam basin. The rainfall fields were generated by three rainfall interpolation techniques (Thiessen polygon: TP, Inverse Distance Weighting: IDW, Kriging) based only on ground gauges and two radar rainfall synthetic techniques (Gauge-Radar ratio: GR, Conditional Merging: CM). Each rainfall field was then assessed in terms of spatial feature and quantity and also used for rainfall-sediment-runoff and erosion-deposition simulation due to the spatial difference of rainfall fields. The results showed that all the interpolation methods based on ground gauges provided very similar hydrologic responses in spite of different spatial pattern of erosion and deposition while raw radar and GR rainfall fields led to underestimated and overestimated simulation results, respectively. The CM technique was acceptable to improve the accuracy of raw radar rainfall for hydrologic simulation even though it is more time consuming to generate spatially-distributed rainfall.

• Journal of Korea Water Resources Association
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• v.45 no.7
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• pp.643-656
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• 2012

There has been an increase for the landslide areas and restoration expenses due, in large part, to the increased locally heavy rains caused by recent climate change as well as the reckless development. This study carried out a slope stability analysis by the application of distributed wetness index, using the GIS-based infinite slope stability model, which took the root cohesion effect into consideration, for part of Mt. Umyeon in Seoul, where landslide occurred in July 2011, in order to compensate the defects of existing analysis method, and subsequently compared its result with the case on the exploitation of lumped wetness index. In addition, this study estimated the distributed wetness index by methodology, applying three methods of specific catchment area calculation: single flow direction (SFD), multiple flow direction (MFD), and infinity flow direction (IFD), for catchment area, one of the variables of distributed wetness indices, and finally implemented a series of comparative analysis for slope stability by methodology. The simulation results showed that most unstable areas within the study site were dominantly located in cutting-area surroundings along with the residential area and the mountaintop and unstable areas of IFD and lumped wetness index method were similar while SFD and MFD provided smaller unstable areas than the two former methods.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.21-31
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• 2011

The Ministry of Land, Transport & Maritime Affairs(former-The Ministry of Construction and Transportation)establish & promulgated the guide line of The Law of Post Evaluation on May 10, 2001(Article 58824-318) to public construction project under the Operation Law of Construction Engineering Management the 18 clause of Article 38 in order to induce & collect useful data about construction project when plan new similar project in the future about the initial planning phase, former and past accomplished businesses to construction works, results, efficiency, effectiveness. Ever since The Ministry revised 5 times, the former contents are composed for SOC, big volume civil project, and revised contents Article 2010-14(Jan 15, 2010) included some architectural project, but that was not definite the evaluation contents, direction & objective standard. So evaluation index implements are ambiguous about accomplished project. This research arranged the correctness evaluation indicators, criterions for decide the grades in order to helpful informations for similar architectural project in the future.

• Journal of the Korean GEO-environmental Society
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• v.11 no.12
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• pp.47-56
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• 2010

The construction of new roads and the consistent extension of already-existing roads or the line-shape revision of those roads are increased with the governmental investment to SOC facilities currently. Accordingly, the road cut slopes are in the trend of rapidly increasing. As the road slope has increased, a lot of human and property damages has entailed consequently and in the local case, numerous studies have carried out aiming at minimizing this damages caused by the rockfall and landslide. In general, standard falling rock prevention facility has employed for most of the local road slope based on "Guide for Installation and Management of Road Safety Facilities" published by MLTM(the Ministry of Land, Transport, and Maritime Affairs) but profound doubt has raised as to whether this rockfall prevention facility would function properly enough to prevent rockfall efficiently without any damages in case of actual occurrence of rockfall. In addition, it is a reality that in most cases, such work is relied on overseas technology as a whole as the local technical level is low and in case of rockfall prevention net, it is judged that a study on rockfall prevention net that is able to endure more powerful rockfall energy is required as the problem including net bursting is taken place as a result of enough bearing force being failed to be demonstrated due to its partial weak point(not uniformly made). Under this background, in this study, three kinds of model depending on mesh size of expanded metal that is considered to have an adoptability as rockfall prevention net, as target are selected and characteristics depending on mesh size of expanded metal is intended to be researched through a pull-out test performance by using pull-out test equipment rockfall prevention net.