• Journal of the Korea Institute of Building Construction
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• v.12 no.1
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• pp.108-114
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• 2012

Escalation method examining the changes in price index has been widely utilized in public construction projects. The previous escalation method determined estimated changes in price based on the average unit price of contract items over a period of time. In relation to this method, the issue has been raised that the fluctuation rates of previous method show different trends compared with other related price indices, as the influence of the small group of contract items with large unit prices overwhelms the others. This research suggested an improved escalation method which estimates the fluctuation rate by examining the changes in CCI (construction cost index) and applies it to the total amount or the partial amount deducted for labor cost in price escalation for previous bid price method. To verify the improvement, a case study is conducted on an educational facility, and the fluctuation rate was estimated in two different base periods (short term, long term). The results over the long term showed similar tendencies to those of related price indices, as well as significant differences in fluctuation rates compared to those of the previous method.

• Journal of Korea Spatial Information System Society
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• v.8 no.1 s.16
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• pp.37-57
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• 2006

To support Location Based Services, the technology to store and search locations information of moving objects effectively was needed. And the study about indexes to manage these moving objects effectively has been done. As these indexes for moving objects was not considered for the objects which are moving along constrained networks such as road and railroad, indexes for the moving objects based on constrained networks was proposed. But these kinds of indexes have two problems as following. First, as the indexes for the moving objects based on constrained networks is divided according to time domain, when the places of moving objects from the present to the past are needed, the problem to search past indexes as well as present indexes occurs. Second, in this case, we should construct both present indexes and past indexes, so we have no other choice but to spend space cost and reconstruction cost additionally. This paper proposes A Unified Index for Moving Objects in Constrained Networks to solve these kinds of problems. As this proposed indexes support both present location and past location of moving objects, it can solve the current problems such as when we search present and past location of moving objects, we need a separate processing procedure. And as it consolidated the common parts of current location indexes and past location indexes, we can use less space cost and reconstruction cost than when we maintain indexes separately.

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.389-399
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• 2010

Available transfer capability (ATC) is a measure of the transfer capability remaining in a transmission system. Application of unified power flow controllers (UPFCs) could have positive impacts on the ATC of some paths while it might have a negative impact on the ATC of other paths. This paper presents an approach to evaluate the impacts of UPFCs on the ATC from a cost/worth point of view. The UPFC application worth is considered as the maximum cost saving in enhancing the ATC of the paths due to the UPFC implementation. The cost saving is considered as the cost of optimal application of other system reinforcement alternatives (except for UPFC) to reach the same ATC level obtained by UPFC application. UPFC application costs include the maximum cost of alleviating the probable negative impact on the ATC of some paths caused by implementing UPFCs. Optimal system reinforcement is used for systems with UPFCs to determine the aforementioned cost. The proposed method is applied to the IEEERTS and the results are evaluated through a sensitivity analysis. The cost/worth of UPFC application is also used to develop an index for optimal UPFC location and the results are compared with those of other indices. A comparison is finally made with the results obtained using an existing ATC allocation profit-based approach to determine UPFC application worth.

• Journal of Korea Multimedia Society
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• v.12 no.10
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• pp.1374-1385
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• 2009

Recently, advances in speed of the CPU have for out-paced advances in memory speed. Main-memory access is increasingly a performance bottleneck for main-memory database systems. To reduce memory access speed, cache memory have incorporated in the memory subsystem. However cache memories can reduce the memory speed only when the requested data is found in the cache. We propose a new cache sensitive T-tree index structure called as $CST^*$-tree for range query search. The $CST^*$-tree reduces the number of cache miss occurrences by loading the reduced internal nodes that do not have index entries. And it supports the sequential access of index entries for range query by connecting adjacent terminal nodes and internal index nodes. For performance evaluation, we have developed a cost model, and compared our $CST^*$-tree with existing CST-tree, that is the conventional cache sensitive T-tree, and $T^*$-tree, that is conventional the range query search T -tree, by using the cost model. The results indicate that cache miss occurrence of $CST^*$-tree is decreased by 20~30% over that of CST-tree in a single value search, and it is decreased by 10~20% over that of $T^*$-tree in a range query search.

• Journal of Korea Spatial Information System Society
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• v.11 no.3
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• pp.55-62
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• 2009

Location based Services in the ubiquitous computing environment, namely u-LBS, use very large and skewed spatial objects that are closely related to locational information. It is especially essential to achieve fast search, which is looking for POI(Point of Interest) related to the location of users. This paper examines how to search large and skewed POI efficiently in the u-LBS environment. We propose the Dynamic-level Grid based R-Tree(DGR-Tree), which is an index for point data that can reduce the cost of stationary POI search. DGR-Tree uses both R-Tree as a primary index and Dynamic-level Grid as a secondary index. DGR-Tree is optimized to be suitable for point data and solves the overlapping problem among leaf nodes. Dynamic-level Grid of DGR-Tree is created dynamically according to the density of POI. Each cell in Dynamic-level Grid has a leaf node pointer for direct access with the leaf node of the primary index. Therefore, the index access performance is improved greatly by accessing the leaf node directly through Dynamic-level Grid. We also propose a K-Nearest Neighbor(KNN) algorithm for DGR-Tree, which utilizes Dynamic-level Grid for fast access to candidate cells. The KNN algorithm for DGR-Tree provides the mechanism, which can access directly to cells enclosing given query point and adjacent cells without tree traversal. The KNN algorithm minimizes sorting cost about candidate lists with minimum distance and provides NEB(Non Extensible Boundary), which need not consider the extension of candidate nodes for KNN search.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.1
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• pp.199-214
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• 2010

Objective : Atopic dermatitis (AD) may profoundly affect patient's quality of life (QOL), and also cause economic impact. The aim of our study was to evaluate the quality of life and the economic impact of adult atopic dermatitis patient in Seoul. We also evaluate the relationship of QOL and economic impact with severity of AD. Methods : 30 adult atopic dermatitis patient were included and evaluated by using the SCORAD Index and EASI. Patients were asked to fill in the questionnaires about their quality of life and financial costs during the past year by AD. Data about sleep disturbance and pruritus were also obtained. Pearson's correlation were used for statistical analysis. Results : 1. Among 30 patients, women were 19(63.3%), men were 11(36.7%). The mean age of the patients were 27.3 years old, patients between the ages of 17 and 30 years were 23, over 30 were seven. 2. The mean score of Objective SCORAD was $32.89{\pm}7.30$, Subjective SCORAD was $8.13{\pm}3.53$ and EASI was $9.15{\pm}6.90$이었다. 3. The mean score of Skindex-29 was $28.26{\pm}7.58$, DLQI was $10.17{\pm}5.55$. 4. By analyzing the questionnaire, a monthly average cost of 583,200 won for each patient was determined. Direct cost was 236,800 won and indirect cost was 346,300 won. 5. By analyzing the correlation between the severity of AD and QOL, Objective SCORAD and EASI were positively correlated with QOL(Skindex-29, DLQI) but not significant, meanwhile subjective SCORAD were significantly and positively correlated with QOL(Skindex-29, DLQI). 6. By analyzing the correlation between the severity of AD and economic impact, Objective SCORAD were significantly and positively correlated with direct cost and indirect cost. Also, EASI were significantly and positively correlated with direct cost and oriental medical hospital visits. Conclusions : The above results show that the QOL of the patients with atopic dermatitis is significantly related to their disease severity. Atopic dermatitis patients pay 583,200 won a month, and the economic impact of the patients is significantly related to their disease severity.

• The Journal of Korea Robotics Society
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• v.7 no.1
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• pp.9-19
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• 2012

This paper proposes a performance index for the multiple shape object handling of dual arm manipulator to determine whether a robot is good or not. When the dual-arm manipulator grasps a fixed object and is posed, the dual-arm manipulator should procure a space to freely control the manipulator. As a performance evaluation parameter, each joint torque from current sensor signal is utilized. From the current information, torque and energy for each joint are estimated. In this paper an performance index for an unstructured object is defined by an energy-cost function, and stability analysis for each motion is derived by the maximum force to the object. The maximum force to the object is computed by the inertia of object and acceleration information of end-effector. The acceleration data are derived by the double derivation of each encoder signal. Manipulability measure which implies how efficiently the dual-arm manipulator can move with the grasped object, can be represented by the intersection of the two manipulability ellipsoids for the left and right arms. Effectiveness of the proposed algorithm has been verified through the practical simulations and real experiments.

• The Journal of Industrial Distribution & Business
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• v.8 no.6
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• pp.33-40
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• 2017

Purpose - This study attempted to discover the impact of the Korea-China FTA(Free Trade Agreement) on electronic products distribution industry. Strategies will be provided to expand both countries' trade after the Korea-China FTA. Research design, data, and methodology - This study analyzed the differences before and after the Korea-China FTA, using an RCA(Revealed Comparative Advantage) index, TC(Technology Sophistication Index) index and TSI(Trade Specialization Index) that considered the FTA tariff situation. Data was collected from the International Trade Statistics Database and Korea, China Customs Service. Results - The results indicate that following the Korea-China FTA, China and Korea's bilateral trade of electronic products is expected to expand, and both countries will experience net welfare gains from the markets' expansion. Korea is competitive in several key products, although it faces competition from China. China's electronic products' competitiveness have indicated an increasing trend. Conclusions - The two countries should closely cooperate and communicate with each other. Ultimately, Korea should focus on high-tech, sophisticated techniques to gain market advantage. On the other hand, with the tariff decrease as well as the labor cost and labor force base, China will greatly be able to benefit from the manufacturing of medium- to low-end products in the future.

• KCID journal
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• v.19 no.1
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• pp.87-96
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• 2012

Information of local solar radiation is essential for many field, including water resources management, crop yield estimation, crop growth model, solar energy systems and irrigation and drainage design. Unfortunately, solar radiation measurements are not easily available due to the cost and maintenance and calibration requirements of the measuring equipment and station. Therefore, it is important to elaborate methods to estimate the solar radiation based on readily available meteorological data. In this study, two empirical equations are employed to estimate daily solar radiation using Cheongju Regional Meteorological Office data. Two scenarios are considered: (a) sunshine duration data are available for a given location, or (b) only daily cloudiness index records exist. Simple linear regression with daily sunshine duration and cloudiness index as the dependent variable accounted for 91% and 80%, respectively of the variation of solar radiation(H) at 2011. Daily global solar radiation is highly correlated with sunshine duration. In order to indicate the performance of the models, the statistical test methods of the mean bias error(MBE), root mean square error(RMSE) and correlation coefficient(r) are used. Sunshine duration and cloudiness index can be easily and reliably measured and data are widely available.

• Journal of Korean Society for Quality Management
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• v.41 no.2
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• pp.221-232
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• 2013

Purpose: This paper examines risk factors which affect project success, and proposes a method utilizing the average potential satisfaction index(API) to evaluate how much the satisfaction level of the personnel involved in the project can change by reducing the risk. Methods: The current study derives 11 risk factors affecting project success from literature review and conducts survey of 253 subjects who have project work experience. A modified Kano's questionnaire using 5-point Likert-scale is applied to investigate the amount of satisfaction or dissatisfaction when the risk factors are reducted or not, respectively. Results: The respondents consider that the risk factors which include the three elements of project management(schedule, quality, cost) is more important than other risk factors related to the project environment, and technology and profitability. Conclusion: The average potential satisfaction index proposed in this study can measure the perception on the risk factors of the personnel involved in the project, since it has a strong correlation with the perceived importance by the respondents in this study.