• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6C
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• pp.251-258
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• 2011

Steel pipe piles have been used as various deep foundation materials for a long time. Recent increase in steel material cost has made engineers reluctant in using it even with its good quality and ease of construction. Therefore when constructing with steel pipe pile, the decision to reuse the excessive pile length that is cut off from the designed pile head elevation after pile driving can be cost saving. This has caused many constructors to reuse the pile leftovers with new piles, but the absence of quantitative structural capacity behaviors of steel pipe pile after pile driving or appropriate countermeasures and standards in reusing steel pipe pile has resulted in wrong applications, pile structural integrity problems, inappropriate limitation of reusable pile length, etc. The structural performance analysis between a new pile and a pile that has undergone working state and ultimate state stress level during pile driving was performed in this research by means of comparing the results between the dynamic pile load test, tensile load test, charpy energy test and fatigue test for high strength steel of $440N/mm^2$ yield strength. Test results show that under working load conditions the yield strength variation is less than 2% and for ultimate load conditions the variation is less than 5% for maximum total blow count of 3000. The results have been statistically analyzed to check the sensitivity of each factors involved. From the test results, reusability of steel pipe pile lies not in the main pipe yield strength deviation but in the reduction of absorb energy, strength changes and quality control at the welded section, shape deformation and local buckling during pile driving.

• Journal of Korea Spatial Information System Society
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• v.7 no.3 s.15
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• pp.119-130
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• 2005

A spatial data warehouse is a system that stores geographical information as a subject oriented, integrated, time-variant, non-volatile collection for efficiently supporting decision. This system consists of a builder and a spatial data warehouse server. A spatial data warehouse server suspends user services, stores transferred data in the data repository and constructs index using stored data for short response time. Existing methods that construct index are bulk-insertion and index transfer methods. The Bulk-insertion method has high clustering cost for constructing index and searching cost. The Index transfer method has improper for the index reconstruction method of a spatial data warehouse where periodic source data are inserted. In this paper, the efficient index reconstruction method using a partial index in a spatial data warehouse is proposed. This method is an efficient reconstruction method that transfers a partial index and stores a partial index with expecting physical location. This method clusters a spatial data making it suitable to construct index and change treated clusters to a partial index and transfers pages that store a partial index. A spatial data warehouse server reserves sequent physical space of a disk and stores a partial index in the reserved space. Through inserting a partial index into constructed index in a spatial data warehouse server, searching, splitting, remodifing costs are reduced to the minimum.

• Korean Journal of Construction Engineering and Management
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• v.9 no.5
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• pp.168-175
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• 2008

Project risk factors are major triggers in cost performance in construction projects. Both owners and contractors are highly concerned in managing their risks in earlier times. As such, it is needed to provide a robust risk evaluation methodology in identifying and assessing the potential risks before project execution. In previous research, risk identification was conducted only in specific phases, i. e., design, procurement, construction. Therefore, the comprehensive approach in risk management was limited and their quantifying method was not well-defined. Since the benefit of planning in earlier times are maximized compared to later times, the risk management should be implemented in earlier planning stage. This study provide a new risk evaluation method by incorporating previous research and extensive literature review. By quantifying each risk factor from an extensive industry survey, the proposed tool can enhance the reliability of each factor weight and also the weights are categorized from a various perspectives, i.e., owners, contractors, lager-scale company, smaller-scale company, building projects. The proposed tool can be also useful in deciding on whether to proceed a particular project and How much the project contingency would be set aside in project execution. The study findings can also expedite the risk management procedure in a more systematic approach.

• Journal of Service Research and Studies
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• v.7 no.4
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• pp.15-38
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• 2017

The purpose of this study is to look into the consumers who show the consumption patterns of brand switching and repeated purchasing, find the decision factors of their brand switching and repeated purchasing, analyze the difference in marketing response variables being represented as corporate promotion activities in the brand switching and repeated purchasing process, and provide a suggestion to apply the result to marketing Therefore, it tries to help the firms, which develop push marketing as the result of excessive competition between distributors and sales competition focusing on external appearance, recognize consumers as individual substances; to propose proper efficient promotion activities; to let consumers increase loyalty to their trademark and continue to purchase their products repeatedly; and to induce competitor brand consumers to do brand switching. The results of this study are presented as follows: First, consumers who prefer events, price discount, samples, and product premium which means the products with brand or logo on them had the feature of repeated purchasing. Secondly, service benefit, point-type promotion, cost-saving satisfaction didn't affect brand switching, and only the consumers who prefer coupon-type promotion did brand switching. Thirdly, a distribution type produced the moderating effect between the repeated purchasing and coupon and coupon-type promotion, and between brand switching and service benefit.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.176-183
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• 2008

Recently, several large-scale Mega-Projects are being conducted. For these urban revitalization projects which requires many complex functions, the existing project management system based on single project level is limited in application. Therefore, our main objectives of this research are two 1) Develop a brand-new program management system(Prototype Ver 1.0) for mega-projects where various facilities are combined both horizontally and vertically. 2) Develop management strategies(Prototype Ver 1.0) based on the program level that enable the comprehensive management of a multiple various projects. The subtitles of this Research are i-PMIS(Program Management Information System) Development, Standardization & Optimization of Construction Life-Cycle Process, Comprehensive Project Cost & Process Management Technology, Effective and Optimized Integrated Performance Management Technology, and, we suggest to optimize the whole life cycle process, predict and respond to various risks, predict and control the process, the cost and the schedule, achieve maximum return on investment to the participating parties, and provide a brand-new Program-MIS including the visual-based web-portal platform to respond the changing business environments and decision making.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.132-142
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• 2018

This study attempts to identify the external and internal factors which affect collaboration motives and investigates their respective impacts from the perspective of foreign direct investment(FDI). Although there has been much research on collaboration motives, so far, few studies have associated collaboration motives with FDI. The findings suggest that while price competitiveness and cost structure uncertainty have a positive and significant impact on collaboration motives, the gross added value to property as well as plant and equipment have a significant negative impact. Furthermore, in the case of gross added value to both property and plant and equipment, managers tend to collaborate with others to enhance the value of these factors. For both FDI and non-FDI firms, internal factors such as price competitiveness and investment within three years are significant determinants for the decision to collaborate. The difference between FDI and non-FDI firms is that for the former, the gross added value to property, an internal factor, is a critical factor, while for the latter, the cost structure uncertainty, an external factor, is critical for collaboration. To summarize, this study suggests the following managerial implication: the enhancement of the internal competency of a firm broadens the window of opportunity for collaboration with others, and consequently provides a chance to boost management efficiency.

• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.248-253
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• 2015

This study applied the portfolio approach as a means to provide decision-making information for the establishment of the optimal production plan for non-timber products. The target items of non-timber forest product were Chestnut, Jujube, Walnut and Astringent Persimmon. The data used in this study were the annual report of forestry production cost survey which contains the annual production, annual gross income, and annual product cost from 2008 to 2013. These data were used to calculate the expected return of non-timber forest product. The objective function in the portfolio models was to minimize the expected return volatility, called risk and the constrain was to achieve the minimum expected return rate. Results indicated that the production ratio of the nuts and fruits in 2013 was 7% for Chestnut, 20% for Jujube, 5% for Walnut and 68% for Astringent Persimmon. Furthermore, portfolio presented that the production ratio was 10% for Chestnut, 9% for Jujube, 3% for Walnut and 78% for Astringent Persimmon in the near future. The cause was analyzed due to maintain stable production and income of Astringent Persimmon and Chestnut. Meanwhile, the revenue of Walnuts and Jujube was in great variation with relatively higher revenues.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.4
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• pp.115-125
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• 2017

In current, as the release of national base map with an equivalent scale and accuracy for the whole territory areas in South Korea, rapid spatial information industry such as national land development, GIS, and car navigation are used in a variety of spatial information industry as decision making method, and a lot of research and policies are proposed for the wide expansion of spatial information industry. For this, as of 2013, it contributes to the latest trend of spatial information field in order to solve the problems for the latest trend of spatial information, replacing modification of base maps as dividing the whole territory to zone with policy transformation by ordinary modifications. Therefore, this paper evaluates the possibility of modification and renewal of national base maps(scale: 1:5,000) using drones which currently get the limelight from a variety of research fields and industries. In particular, as a result of overlapping orthophoto, 3D point clouds extracted from images acquired by low-cost drones, and digital maps which are applied for the tasks of modification and renewal, it presents 0.2m precision and 0.1m accuracy. This means that drone-based photorgammetry technique can be fully utilized in the tasks of digital map modification and renewal because it conforms the error range of work regulation in making the national base maps(scale 1: 5000).

• The Journal of Society for e-Business Studies
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• v.16 no.4
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• pp.139-154
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• 2011

Recently Internet keyword search service providers tends to use CPC advertizement method rather than CPM method. However researches how much the CPC method is beneficial to advertisers than CPM method in certain perspectives are insufficient and not performed systematically. So this paper tries to do comparative analysis about the two methods by analyzing the real transactional DB data from an advertizement agency. Due to the difficulties of direct comparison between the two methods because of their different expose positions on the Web and different types of attributes in DB, we did some preprocessing step for the transactional data. From the result of analysis, the click rate of CPC is higher than CPM by 1.3% and the unit cost for the CPC per one click is lower than CPM method by 51 Won. It shows the CPC method is more effective than CPM method for advertizement from the point of advertizement effectiveness (CTR) and advertizement cost (CPC). We hope this research would give useful information to advertisers and marketing managers in making advertizement strategy, marketing decision and budgeting.

• The Korean Journal of Financial Management
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• v.22 no.1
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• pp.1-36
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• 2005

In this study, we analyzed determinant factors of leverage ratio and debt maturity for Korean firms in the simultaneous equation system using 2SLS (two stage least square) method under assumption that two variables are jointly determined in the capital structure decision. As a result of the analysis, we found that leverage ratio and debt maturity are positively related. Also, as for determinant factors of debt maturity, agency cost hypothesis, asset maturity matching hypothesis, signalling and liquidity risk hypothesis are all generally supported, and further leverage ratio are significantly positively related with firm size, but negatively related with default risk. However, when we divided samples into groups according to bank debt level and Chaebul affiliation, with contrast to existing study which worked on similar issues with OLS, we found no evidence supporting the argument that the information asymmetry problem is less severe in firms with more bank debt, whereas information asymmetry and financial constraint problems are more severe in non-Chaebul affiliated firms.