• Korean Journal of Computational Design and Engineering
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• v.14 no.1
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• pp.18-24
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• 2009

This paper proposes an analytical method of evaluating the maximum error by modeling the exact tool path for the tool traverse singular region in five-axis machining. It is known that the NC data from the inverse kinematics transformation of 5-axis machining can generate singular positions where incoherent movements of the rotary axes can appear. These lead to unexpected errors and abrupt operations, resulting in scoring on the machined surface. To resolve this problem, previous methods have calculated several tool positions during a singular operation, using inverse kinematics equations to predict tool trajectory and approximate the maximum error. This type of numerical approach, configuring the tool trajectory, requires much computation time to obtain a sufficient number of tool positions in a region. We have derived an analytical equation for the tool trajectory in a singular area by modeling the tool operation into a linear and a nonlinear part that is a general form of the tool trajectory in the singular area and that is suitable for all types of five-axis machine tools. In addition, we have evaluated the maximum tool-path error exactly, using our analytical model. Our algorithm can be used to modify NC data, making the operation smoother and bringing any errors to within tolerance.

• 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.

• Korean Management Science Review
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• v.19 no.2
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• pp.91-124
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• 2002

The use of network planning models and tools is essential for effective KII (Korea Information Infrastructure) planning and analysis in that it will significantly reduce the risk and uncertainty embeded in the development and the provision of future broadband services. The purpose of this study is to develop a theoretical framework and a computer tool for modeling the various aspects of the KII topology and architecture and evaluating the techno-economic feasibility of the KII implementation strategy.

• 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.

• Journal of Korea Society of Industrial Information Systems
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• v.2 no.2
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• pp.159-179
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• 1997

Traditionally, the evaluation and selection of suppliers have been a major purchasing function. A growing concern for just in-time purchasing, global sourcing, and long-term partnership between buyers and suppliers makes selecting a righ supplier become more critical decision making process. Consequently, a rigorous and systematic method for evaluation suppliers is a must. However, assessing the values of factors(e.g. qulaity , delivery, and service) selected for evaluating suppliers contains elements of uncertainty. Although several methods have been developed for uncertainty analysis, they may not be proper tools for evaluating suppliers under uncertainty. In this paper, a methodology using a fuzzy-set approach in combination with a multicriterion decision-making (MCDM) technique is developed to use as a tool for evaluating suppliers under uncertainty. An numerical example is presented to demonstrate the method in practice.

• Korean Management Science Review
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• v.17 no.3
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• pp.161-180
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• 2000

The purpose of this paper is to propose an analytical model for evaluating Internet Web sites, that is comprehensive and flexible enough to accomodate different categories of Internet Web sites. This paper is intended to identify critical success factors of Internet Web sites to determine criteria for evaluating the Web sites, and use the criteria to develop a framework for comprehensive evaluation of Internet Web sites. The framework consists of eight categories, including design, business functions, trustworthiness, interface, technology, community, contents, and others. An empirical study designed to validated the framework has been conducted for each of the three Web site categories, including (1) information provision, (2) product sale, and (3) customer service. The results show that ‘content ’ is the most important for information provision Web sites, ‘trustworthiness’for product sale Web sites, and ‘design’ for customer service Web sites. The framework may be used not only as a tool to evaluate Internet Web sites, but also as a checklist to improve the quality of a Web site that is under development.

• Journal of the Korea Safety Management & Science
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• v.5 no.2
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• pp.215-223
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• 2003

GE, as well as Motorola, TI, HP, ABB, and other companies, which have several suppliers from all of the world, adopted an innovation program called 6 Sigma, in order to make fundamental changes in the way they operated to fulfill customers' expectations and to evaluate and control their suppliers. Recently, as the 6 Sigma is being recognized as elementary and strategic means to improve the effectiveness of SCM(Supply Chain Management), there may be few business who does not operate 6 Sigma innovation program. Under such a circumstance, this study is aimed at expediting 6 Sigma pervasion by considering supplier evaluating scheme. It is recognized that this evaluating mechanism can be used as a great tool for the everlasting run of 6 Sigma in Korea.

• Journal of Korean Society for Quality Management
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• v.25 no.2
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• pp.169-188
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• 1997

The purpose of this study is concerned with suggesting a new a, pp.oach to evaluating the overall product quality in the sense of the relative efficiency of products, whose quality is measured with 8-dimensional attributes, suggested by Garvin. The attributes included 8 quality measures, that is, performance, features, reliability, conformance, durability, serviceabilit, aesthetics, and perceived quality. This study, also, introduced DEA(Data Envelopment Analysis) as an evaluation tool to tackle the problem of how to measure one product against another when each product can be measured along a number of dimensions, and given that there exists no a priori satisfactory weighting scheme to combine these dimensions into an overall rating for each products. In order to a, pp.y the DEA to evaluating the products, we must define two concepts, such as DMU(Decision Making Units) and input-output relationship. Finally, the suggested method in this study was validated through a case study of the electric jar, and this DEA a, pp.oach can be used in evaluating the other products with multi-attrribute quality.

• KIEAE Journal
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• v.9 no.5
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• pp.13-20
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• 2009

This study suggested practical application of decision aid tool on re-evaluation of current buildings with a focus on a energy and economics evaluation methodology. In Europe, over forty percent of all construction activities are for retrofit. For efficient construction, various tools for re-evaluating existing buildings have been developed and are in use. Legislations of relevant laws and studies are actively initiated. In particular, EPIQR (Energy Performance Indoor environment Quality Retrofit), which was developed through the EU's Third and Fourth Framework Programs laid a foundation on a new concept-based decision aid tool for re-evaluation of existing buildings. As for actual applications, based on this, EPIQR+ was developed to be in line with a building maintenance guideline (SIA 469) and is actively applied to public buildings. This tool quantifies the degree of damages of existing buildings and suggests alternatives to users in energy (SIA 380/1) and economical perspectives. This study examined these preceding tools and suggested some trenchant approaching for more comprehensive and efficient use of re-evaluation tools in building maintenance.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.310-315
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• 2011

General portal machine represents a distinct weak spot concerning their structural behavior because of long protruding structure components, such as saddles and rams. The weak point causes the deformation of the machine tool and consequently rises a severe machining error. The purpose of this study is to improve the structural design of crossrail in order to minimize it's distortion. Tool Center Point (TCP) was chosen as a reference point for evaluating the distortion effect of a crossrail and topological optimization was adopted as a method of structural design improvement. The displacements of TCP according to the machining positions were investigated by structural analyses for both of original crossrail design and the improved one. The comparing results showed that the displacement of TCP could be reduced about 55% maximum.