• International Journal of Contents
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• v.3 no.2
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• pp.6-17
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• 2007

Emerging modem database applications require multi-dimensional index structures to provide high performance for data retrieval. In order for a multi-dimensional index structure to be integrated into a commercial database system, efficient techniques that provide transactional access to data through this index structure are necessary. The techniques must support all degrees of isolation offered by the database system. Especially degree 3 isolation, called "no phantom read," protects search ranges from concurrent insertions and the rollbacks of deletions. In this paper, we propose a new phantom protection method for multi-dimensional index structures that uses a multi-level grid technique. The proposed mechanism is independent of the type of the multi-dimensional index structure, i.e., it can be applied to all types of index structures such as tree-based, file-based, and hash-based index structures. In addition, it has a low development cost and achieves high concurrency with a low lock overhead. It is shown through various experiments that the proposed method outperforms existing phantom protection methods for multi-dimensional index structures.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1335-1340
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• 2009

In order to establish railway long-tenn safety policy, various railway safety indexes are required. But these indexes are not use efficiently due to the limitation of safety information. Recently m any safety related information have been obtained based on Railway Safety Act 2004. In this study, various safety index, which can be applied both preventive safety activities and safety measure development, are proposed. These safety indexes are based on common safety index in European Railway Agency, but also include special index in Korea. Proposed safety index include accident results, precursors to accident, infrastructure, accident cost and safety management system. These indexes will be applied in railway industry from 2009.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.453-454
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• 2007

This paper proposes the calculation method of voltage sensitivity index using CBEMA power acceptability curves and the voltage curves of the load bus to which momentary events occur. Voltage sensitivity index is represented by areas between two curves. Voltage sensitivity index is a parameter that depicts the ratio of a load disruption. The correlation between the installation cost of compensation devices and the voltage sag index on the bus can be used the validity of compensation.

• Journal of the Korea Institute of Building Construction
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• v.8 no.6
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• pp.65-74
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• 2008

The aim is to get comprehensive view point for the price of apartment. Apartment construction cost is the sun of land cost and building cost. Land price reflects the value of location where building stands. When the gap between price and affordability is narrow enough, effective demand promote apartment construction. The today's trends of rising price, which began in apartment housing, spreads to real estates market and finally overall consumer price. Problem is that price is decided only by supplier's interest. Equilibrium-pricing is common process in housing market. However it is important to review hedonic price and the factor of housing services and focused on the affordability of demanders. AHP analysis was used to study real needs and preference of demanders and dealt with 200 interviewees with brief checklists. We found that social factor is more important than building cost or site development. Especially location of apartment is most important to affect environment quality and accessibility to facilities.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.149-151
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• 2012

Changes in the price of materials in construction projects is one of the important variables. Therefore, measures are necessary to respond to the demand and supply of materials and price instability. In previous studies, mainly of ready-mix concrete and steel beam analysis was carried out. However, a study of non-ferrous material prices are still insufficient. So, in this study, the researcher identified the causal relationship between the construction cost and non-ferrous materials prices. Construction Cost Index was selected as a proxy variable of construction cost.

• Korean Journal of Construction Engineering and Management
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• v.10 no.3
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• pp.130-138
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• 2009

Bromilow's time-cost (BTC) relationship was examined for building projects in Vietnam using actual construction time and total construction cost. Data set was collected from 77 historical building construction projects completed between 1999 and 2005 which were adjusted by consumer price index (CPI) to 2000 price. Time-cost equations were specified respected to two sectors, public and private, in Vietnamese construction industry and all cases. It is shown that a public funded building project has the longer construction duration than a similar budget private funded project. The resulting models are statistically significant. The adjusted R-square coefficients of all cases, public and private projects models are respectively 0.403, 0.436 and 0.377 mean that the BTC regression lines moderately fit the data set.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.267-269
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• 2001

This paper presents algorithms to evaluate reliability of distribution power system taking into consideration customer interruption cost. Customer interruption cost is considered as one of the valuable index to estimate reliability of the distribution power system from customer situation. Also, this paper estimate evaluation results regarding the reliability of distribution power system using a sample model system. Finally, evaluation results of unserved energy and system interruption cost based on customer interruption cost are shown in detail.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.4
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• pp.189-199
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• 2002

This study is intended to propose a systematic procedure for the development of the conditional assessment based on the safety of structures and the cost effective performance criteria for designing and upgrading of bridge structures. As a result, a set of cost function models for a life cycle cost analysis of bridge structures is proposed and thus the expected total life cycle costs (ETLCC) including initial (design, testing and construction) costs and direct/indirect damage costs considering repair and replacement costs, human losses and property damage costs, road user costs, and indirect regional economic losses costs. Also, the optimum safety indices are presented based on the expected total cost minimization function using only three parameters of the failure cost to the initial cost (${\tau}$), the extent of increased initial cost by improvement of safety (${\nu}$) and the order of an initial cost function (n). Through the enough numerical invetigations, we can positively conclude that the proposed optimum design procedure for bridge structures based on the ETLCC will lead to more rational, economical and safer design.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.83-84
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• 2015

Remodeling of apartment houses has been increasing recently and residents have chosen to extend the balcony along with the legalization of balcony extension in apartment houses. Balcony extension provides residents more space, however, it has been investigated that balcony extension increases construction cost, heating and cooling cost and decreases sound insulation performance. Therefore, this study focuses on developing a decision making index for residents in remodeling required apartment houses. The suggested methodology involves surveying actual residents, survey analysis by AHP and decision model development using logistic regression analysis.

• The Korean Journal of Health Service Management
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• v.11 no.1
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• pp.11-25
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• 2017

Objectives : The purpose of this study is to analyze the differences in financial performance, productivity, and patient care performance between metropolitan and non - metropolitan hospitals and examine the factors affecting profitability of both groups. Methods : The survey period consisted of three years of data that can identify the financial performance of the hospital. The survey subjects were selected from 58 metropolitan hospitals, 87 non - metropolitan hospitals and 147 hospitals. Results : There was a significant difference in stability, activity, cost index, productivity, and patient care performance between the metropolitan and non - metropolitan hospitals, and metropolitan hospitals showed a relatively higher ratio. Conclusions : In the metropolitan and non-metropolitan hospitals, the variables of productivity and cost index increase the profitability. However, if the factors with less influence on the results of the study are applied to the variables of various situations, it may have a great influence on the profitability increase.