• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.36.2-36.2
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• 2010

Followed the System Design Review (PDR) of a mobile SLR (Satellite Laser Ranging) system, a successful preliminary design review was finished in 2009. With the completion of this mobile SLR system, KASI (Korea Astronomy and Space Science Institute) can perform a series of test observation and calibration/validation procedures. After the operation performance of the whole system reaches the nominal design, a regular scheduled observation will be executed. However, the project has been disturbed by the frequent change of working staff, budget profile, and plan as well as the inexperienced man power. In this study, the contents and the issues of PDR are briefly reviewed and several items of SLR system are suggested. This mobile SLR system will push Korea's Space Geodetic study further and will make us jump to another step to the Space Science in Korea.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1430-1432
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• 2003

Agricultural areas in the north region of Bangladesh suffer from water shortages during the dry season as well as dry spells in the monsoon period. The Teesta Barrage was constructed in 1990 to provide supplemental irrigation water during the monsoon period. After completion of the project high yielding variety of crops were introduced more in the project area. Due to this reason unforeseen needs of irrigation water during the dry season has emerged. This study reviews the current irrigation status and related constraints to a full development of the project and provides suggestions for future improvement of the project. Also suggested is to apply remote sensing technique for the management of the system as a whole. Use of remote sensing technique for the management of irrigation water resources is a new approach in Bangladesh. Application of such a powerful tool will provide better management options for large-scale irrigation projects in the country.

• Journal of the Korea Institute of Building Construction
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• v.11 no.5
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• pp.482-500
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• 2011

In apartment housing construction, window frame installation work, which is conducted after the structural framework, is very important, because its completion time directly affects the starting time of successive interior finishing works, as well as the overall construction period. Construction delays in interior finishing works might occur due to problems inherent to the conventional window frame installation method, such as the poor verticality of window frames, and the water leakage around them. The primary objective of this study is to analyze the problems of a 'Gangform integrated PVC window frame pre-installation method' based on its pilot test results. Next, this study proposes an improved conceptual model that enables the end users to enhance the field applicability of this method in terms of productivity, time, and cost. The field applicability of the proposed 'Gangform integrated PVC window frame pre-installation method' was also verified through a survey.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.408-420
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• 2010

It is important to forecast the final deformation of a tunnel during construction for evaluating its mechanical stability. In this study, the final deformation of a tunnel is forecasted by fitting tunnel deformations measured while excavating to a displacement function and exterpolating it. The tunnel for the study was built in two stages divided into an upper and a lower part. During the lower part construction of the tunnel, the displacement function forecasts the final incremental displacement well compared to the increment measured after completion of the tunnel. It is because the critical initial displacement occurred on passing the measurement pins can be adequately measured during excavating the lower part, which can not be measured during the upper part excavation of the tunnel.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1337-1344
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• 2016

As the visual effect frequently used in movies or animations, special effects are well suited for the creation of buildings or materials' destruction and collapse scenes. With the relevant programs developing technologically, the adoption of a real-time physically based-system makes it possible to realistically express dynamic simulations. In the large scale, the visual expression of such effects of destroying is satisfying enough, but most common programs of those effects fail to maximize visual effect generated with the cutting of small materials. Besides, to perform a heavy simulation process needs high-performance hardware and programs, where high costs would become a serious issue. For this reason, this paper suggests a solution optimized for the effect of small materials-cutting. The progress of each step shows technologies which trace movement with the state of the completion of the character's motions and then cut the material in real-time, finally led to the very realistic visual effect. Besides, using vector inner calculation to follow the motions of object and to realize cutting effect, this study provides an experiment that constructs visual effect for visualization from the basis of mathematical algorithm and it would be certainly as an educational material used for further researches.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.2051-2057
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• 2008

This paper is a feasibility study on the calculation of operating cost in regards to the overall operation following the completion of a number of LRT lines currently in progress. Owing to the absence of operating experience in driveless LRT system at home, the difficulties lie in the assumption of the optimal operating budget applying domestic real situation. Nevertheless, with 34 years of accumulated operating experience in heavy rail transit system, Seoul Metro, the nation's biggest urban rail transit operator, performs O&M consultancy services for several on-going projects along with every effort to acquire know-how where the appropriateness of the cost estimation as a required deliverable is reviewed and a more efficient way is provided. The main focus of this study is to seek a method to calculate the optimal amount of operating expenses as well as a cost-effective alternative for possible weaknesses from the standpoint of the operator. The body of this paper discusses the five issues such as personnel cost, overhead, maintenance cost, additional purchase price, alternative investment fee from a more macroscopic point of view, and the conclusion deals with the adequacy of the reason for selection of institutions with various operating know-how.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.4108-4122
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• 2019

Workflow process mining is becoming a more and more valuable activity in workflow-supported enterprises, and through which it is possible to achieve the high levels of qualitative business goals in terms of improving the effectiveness and efficiency of the workflow-supported information systems, increasing their operational performances, reducing their completion times with minimizing redundancy times, and saving their managerial costs. One of the critical challenges in the workflow process mining activity is to devise a reasonable approach to discover and recognize the bottleneck points of workflow process models from their enactment event histories. We have intuitively realized the fact that the iterative process pattern of redo-activities ought to have the high possibility of becoming a bottleneck point of a workflow process model. Hence, we, in this paper, propose an algorithmic approach and its implementation to discover the redo-activities and their performers' involvements patterns from workflow process enactment event logs. Additionally, we carry out a series of experimental analyses by applying the implemented algorithm to four datasets of workflow process enactment event logs released from the BPI Challenges. Finally, those discovered redo-activities and their performers' involvements patterns are visualized in a graphical form of information control nets as well as a tabular form of the involvement percentages, respectively.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.285-291
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• 2018

The impact of climate change on animals has been globally documented. Especially, migration of birds has been extensively monitored as migratory birds are susceptible to any changes occurring both on breeding grounds and on wintering grounds. However, in contrast to spring migration, the patterns and the factors for autumn migration have not been well documented. In this study, we investigated the relationship with climate condition and the first arrival dates (FADs) of bean geese (Anser fabalis) and white-fronted geese (A. albifrons), the representative group of wintering birds in South Korea, using the data collected by Korean Meteorological Association during 1995-2016. Average temperature of September in wintering grounds has increased, and the FADs of the geese have advanced over the 22 years. Even when the influence of autumn temperature was statistically controlled for, the FADs of the geese have significantly advanced. This suggests that warming has hastened the completion of breeding, which speeded up the arrival of the geese at the wintering grounds. In order to assess the effect of climate condition on the arrival of the wintering migratory birds such as the geese in more detail, extensive data collection over many sampling sites and with long-term monitoring is needed.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.5
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• pp.119-127
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• 2018

This study examined the construction method shown in literatures and materials discovered in rampart, barbican and guard platform for Cheongdo-Eupseong castle which was constructed immediately before Japanese Invasions of Korea (1592-98). According to the result of the examination, the construction method used in the coastal areas and inland areas of Gyeongsang province in the early Joseon period was applied to the rampart, barbican and guard platform in the east and north castle walls, which was constructed earlier than other parts of Cheongdo-Eupseong castle. However, from the western end of the northern castle wall, which was later constructed, to the western castle wall was rebuilt using a construction method different from the method applied to the parts that were constructed earlier after Japanese Invasions of Korea. Cheongdo-Eupseong castle was constructed on a flatland on a large scale and at a low height under unreasonable pressures to construct the castle in a short period of time for military defense as well as civil agitation in the imminent situation just before the outbreak of Japanese Invasions of Korea. In addition, various methods of constructing Eupseong castle utilized at that time were used together, and barbican and guard platform were built generally focusing on rapid completion and convenience, using other methods than the one mainly used at that time. This is the reason why there was a difference in the characteristics of the method and period of castle construction between Cheongdo-Eupseong castle and other Eupseong castles in the coastal areas and inland areas of Gyeongsang province.

• Korea Trade Review
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• v.44 no.6
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• pp.87-103
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• 2019

L/C(Letter of Credit) is a common payment term designed to prevent credit risk in international trade. However, most companies prefer T/T (Telegraphic Transfer) payment due to its time and cost efficiency. According to related statistics, more than 70% of international trade contracts are based on T/T rather than other payment terms. The time required from the export negotiation to the completion of the export transaction and collection in international trade is very long. In this process, disputes related to settlement are continuous, so caution should be exercised. Therefore, whether or not the export payment is recovered in a timely manner is the core issue of trade transactions for exporters. The purpose of this study is to identify problems that cause delayed payments during settlement by the remittance (T/T) method, which can lead to settlement risk, in order to investigate those factors which can lead to delays in payments and increased risk as well as to determine ways to prevent such factors in advance. According to empirical findings, trading experience, transaction duration, and contract contents can be important determinants in terms of payment delays. Industry uniqueness and market uncertainty were found to be in opposition to the hypothesized relationships. The results of this study will be useful for trading companies to reduce their payment risk.