• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.797-799
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• 1996

This paper presents a simple method for evaluating of voltage stability using the line flow equation. Line flow equations($P_{ij}$, $Q_{ij}$) are comprised of state variable, $V_i$, ${\delta}_i$, $V_j$ and ${\delta}_j$, and line parameter, r and x. Using the feature of polar coordinate, these equations become one equation with two variables, $V_i$ and $V_j$. Moreover, if bus j is slack bus or generator bus, which is specified voltage magnitude, it becomes One equation with one variable $V_i$, that is, may be formulated with the second-order equation for $V_i^2$. Therefore, solutions are obtained with simple computation. Solutions obtained are used for evaluating of voltage stability through sensitivity analysis. Also, considering of reactive power source, method for evaluating the voltage stability is introduced. The proposed method was validated to 2-bus and IEEE 6-bus system.

• Journal of Korea Foundry Society
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• v.21 no.3
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• pp.198-203
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• 2001

In determining properties of ductile cast iron, it is well known that nodularity plays a significant role. Therefore, the national and/or international standards for ductile cast iron such as KS, ISO, ASTM and JIS have specified some methods for evaluating it. However, most of standards have not recommended the methods using image analyzer which is known as an objective analyzing tool for evaluating microstructure. In this study, a reliable method for evaluating nodularity by image analyzing method was proposed, and the result was compared with that from the common counting method proposed in KS D 4302-1999. It was found that there was a reasonable relationship in nodularities measured by these two methods.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.3
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• pp.46-50
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• 2008

The present status and future prospects of the levitation mass method (LMM), a technique for precision mass and force measurement, are reviewed. In the LMM, the inertial force of a mass levitated using a pneumatic linear bearing is used as the reference force applied to the objects being tested, such as force transducers, materials, or structures. The inertial force of the levitated mass is measured using an optical interferometer. We have modified this technique for dynamic force calibration of impact, oscillation, and step loads. We have also applied the LMM to material testing, providing methods for evaluating material viscoelasticity under an oscillating or impact load, evaluating material friction, evaluating the biomechanics of a human hand, and generating and measuring micro-Newton-level forces.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.257-266
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• 1999

The objective of this study is to suggest DARE (Decision Alternative Ratio Evaluation) Method, which is usually using in VE(Value Engineering), as one of the evaluating alternatives techniques, especially deciding location. The process of solving location problem consists of 4 stages which are Data gathering and Confirming check list, Design of evaluating methodology, Evaluating, and Conclusion. In second stage which is the most important one among those, DARE method is adopted to solve location problem as a objective and scientific technique. The members who are participated workshop extremely agree to whole procedure of methodology and also their own conclusion through Workshop. This case study shows DARE method fits with select optimal location.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05c
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• pp.89-97
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• 2009

As landscaping building roofs and concrete structures increase gradually for low carbon green growth policy of government, But waterproofing membranes of those structures are effecting by root penetration of landscape plant. 80, we progressed study about test method for fast evaluating root resistance of waterproofing materials jointly with Tokyo Institute of Technology. The result of the study is as follows: (1) The penetrating load of the needle at the displacement speed of 1mm/min was measured for various membrane to basis and lap joints of membrane, the load force was $3{\sim}50$ N by material variously. (2) According to the test method of deriving rhizomes of bamboo grass to basis and lap joints of membrane, there were no penetrated membrane until present, but need persistent observation. (3) Test method of deriving rhizomes of bamboo grass to basis and lap joints of membrane can shorten from period of 2 years to 1 year for testing. Because rhizomes of bamboo grass can grow from May to September, test is possible in same period.

• Journal of the Korean housing association
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• v.20 no.4
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• pp.131-142
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• 2009

High-rise and high-density apartment complexes have been built and supplied on a large scale in the 1st period of the New Town project in metropolitan areas since the late 1980s. Now It has become necessary to improve those apartment complexes, which have serious deterioration problems for aging more than about 20 years accompanying simultaneity and a large scale. The purpose of this research is to develop the evaluating indicators to measure the level of deterioration of apartments inclusively and practically in order to regenerate apartments as sustainable residential environments. This study is composed of the following four parts; (a) establishing the conceptual model of evaluation of apartment deterioration, (b) selecting evaluation items, (c) constituting evaluation measurement, and（ｄ)weighting evaluation indicators. First, deterioration of apartments was conceptualized by physical. social, and economical aspects in terms of sustainable development and proposed the conceptual model of hierarchy structure of evaluation of apartment deterioration by literature reviews. Second, evaluating items were selected based on literature reviews of existing indicators and preceding studies about apartments of Korea and foreign countries. The evaluating indicators were identified as a total of 77 evaluating items which were composed of three dimensions and 9 attributes on the basis of the conceptual model. They cover comprehensive scope of the apartment such as unit, building, complex, and site. Third, as the measurement, the 5 point ordinal scale measure was suggested. The evaluating measurement including measure standards, measure methods, and measure contents were developed by each evaluating items. Lastly, the weighting of evaluating indicators was analyzed by AHP method conducted by survey on the expert group. Items were identified as high contributors or low contributors. The weighting of these items could suggest several evaluations according to the situation. The evaluation of the level of deterioration can be done by both total evaluation and a specific field of evaluation. In addition, it is easy to grasp deteriorated attributes or dimensions by providing a radar and bar chart showing evaluation results. These evaluating indicators could be a useful tool to grasp actual methods for the regeneration of apartments.

• Journal of the Korean Data and Information Science Society
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• v.9 no.2
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• pp.323-336
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• 1998

This thesis is to propose the method of evaluating the validity in stages on the design of a checklist based on the estimate theory of the validity on the design of a checklist and the method of evaluating the validity accordy to the purpose for usiug checklist and establish the standards of estimating the validity in stages on the checklist owing to the estimate theory with the journal, Journal of the Korean Society of Clothing and Textiles. We are emboding the statistical consulting server using the proposed estimate method of the validity and the followings we the questions to solve in future. First, there are many kinds of the statistical methods used in the fields of learing and applied technalogy. So we must establish the statistical standars required in each field and study and develope the special statistical checklists. Second, it is neded to systemize the estimate methods and standard on the validity by building the statistical consult DB, evaluate the researchers according to the degrees of statistical knowledge the validity of study design iud propose the delicate and generalized statistical methods appropriate to the ability of researchers.

• Journal of Digital Convergence
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• v.8 no.3
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• pp.19-37
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• 2010

One of the core issues in the realization of e-government is the effective implementation of a website. The current trend of e-government is developing individual web sites and portals, covering such fields as education, tax, economics, real estate, travel, and health. Evaluating e-government web sites is essential for improving web sites. These principles can be included in usability in a broader concept. Website usability has attracted considerable research on website evaluation and has been regarded as one of the most important criteria for measuring and evaluating websites. Usable e-government web sites make citizens willing to search for helpful information or solve their civil applications. The objective of this paper is to suggest an Analytic Hierarchy Process (AHP) method for evaluating e-government web sites. The proposed AHP method has two special characteristics compared to general AHP approaches. First, all citizens who are e-government users can evaluate both the usability criteria and the web sites, but the weighting mechanism differs between criteria and web sites. Secondly, a pairwise comparison is time-consuming and not cost effective with many criteria. Therefore for evaluating a website with respect to a sub-criterion, we develop checklist items as measure scales with a seven-point rating. This method is efficient as it enable us to avoid the pairwise comparison mechanism between sub-criteria. A new computation procedure for the AHP is developed that combines and synthesizes priorities of portals in the case that two decision maker groups are involved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.737-744
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• 2007

It need estimation model who is efficient and estimate correctly organization's information security level to achieve effectively organization's information security target. Also, estimate class information security level for this and need reformable estimation indicator or standard and estimation methodology of information security systems that application is possible should be studied in our country. Therefore many research centers including ISO are preparing the measuring and evaluating method for network duality. This study will represent an evaluating model for network security based on checklist. In addition, we propose ah measuring and evaluating method for network performance. The purpose of two studies is to present the evaluating procedure and method for measuring security of network on set workwill be identified and a measuring method and procedure will be proposed.

• Journal of the military operations research society of Korea
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• v.15 no.2
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• pp.160-169
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• 1989

This study is concerned with the loss rate calculation for evaluating the safety of aircraft series. The objective of this study is to provide the estimation method of safety for the determination of aircraft series, when the aircraft is directly purchased off-the-shelf or co-produced. Especially, in case the initial operation capabilities of alternative aircrafts are substantially different, this research proposes the modified cumulative average method which can effectively estimate the safety of aircraft.