• International Journal of CAD/CAM
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• 제7권1호
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• pp.81-89
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• 2007

As the modular production is an important issue in globalized manufacturing industries, sub modules or parts of the final product are provided by many suppliers. Some part suppliers design their own products for themselves. In some cases, part supplier may provide the same type product to multiple 1-tier companies. Because all suppliers and 1-tier companies can not use the same CAD system in general case, the engineering change in the CAD model of one company could not propagate to related CAD models of other companies directly. Although they use the same CAD system, it is hard to share their CAD model with each other because of company security policy. In this paper, the neutral reference model, which consists of the neutral skeleton model and the external reference model, is proposed to apply a global top-down modeling approach to collaborating companies.

• Journal of Computing Science and Engineering
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• 제4권2호
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• pp.173-187
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• 2010

Recent technological advances in mobile communication systems have made explosive growth in the number of mobile device users worldwide. One of the most important issues in designing a mobile computing system is location management of users. The hierarchical systems had been proposed to solve the scalability problem in location management. The scalability problem occurs when there are too many users for a mobile system to handle, as the system is likely to react slow or even get down due to late updates of the location databases. In this paper, we propose a top-down clustering algorithm for hierarchical location database systems in a wireless network. A hierarchical location database system employs a tree structure. The proposed algorithm uses a top-down approach and utilizes the number of visits to each cell made by the users along with the movement information between a pair of adjacent cells. We then present a modified algorithm by incorporating the exhaustive method when there remain a few levels of the tree to be processed. We also propose a capacity constraint top-down clustering algorithm for more realistic environments where a database has a capacity limit. By the capacity of a database we mean the maximum number of mobile device users in the cells that can be handled by the database. This algorithm reduces a number of databases used for the system and improves the update performance. The experimental results show that the proposed, top-down, modified top-down, and capacity constraint top-down clustering algorithms reduce the update cost by 17.0%, 18.0%, 24.1%, the update time by about 43.0%, 39.0%, 42.3%, respectively. The capacity constraint algorithm reduces the average number of databases used for the system by 23.9% over other algorithms.

• Spatial Information Research
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• 제17권1호
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• pp.131-144
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• 2009

최근 국내의 많은 지방자치단체에서는 정보통신 기술과 도시개발 기술을 융합하여 유비쿼터스 도시(U-City)를 건설하려고 하며, 세계적으로도 많은 도시들이 도시의 경쟁력 강화와 도시민의 삶의 질 향상을 위해 U-City를 개발하기 위해 노력하고 있다. 이러한 시대적 흐름에 따라 각 지방자치단체와 사업 시행자는 최적의 U-City를 구축하기 위하여 많은 방법론을 개발하고 있으며, 기존의 도시개발 방식과 정보화 구축 방식을 연계시키는 등 다양한 개발 절차를 모색하고 있다. 가장 많이 사용되고 있는 방안으로는 도시개발 계획 당시에 개발 될 도시의 정보화 전략계획(ISP)을 수립하는 것이다. 다양한 도시의 환경과 구축기간, 예산, 정보화 기술 등 여러 변수들이 있어 동일한 방법으로 모든 경우에 대한 구축 방안을 수립하기는 어렵다. 따라서 도시 비전과 전략, 서비스와 요소기술의 선정 등에 대한 방안이 필요하게 되었다. 본 논문에서는 U-City를 위한 비전, 전략 수립모형을 만들고 이를 구축할 수 있는 방안으로 하향식 그리고 상향식 접근방법을 제시한다. 또한 U-City를 건설하기 위한 일반적인 추진방법론에 대해서 분석하고 이러한 방법론 안에서 도시 비전 수립을 위하여 두 개의 접근방법을 구성하는 방안에 대하여 논한다.

• 대한치과의사협회지
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• 제52권7호
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• pp.416-424
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• 2014

The purpose of this study is to analyze the cost of dental implant by top-down method and, on that basis, to provide salient information for the suitable standard of dental insurance fee. A survey data and accounting documents from 36 samples of dental clinics secured with the organisation authority are used and analysed for extracting the representative sample of dental clinic. A researcher visited the dental clinics in person and conducted additional interviews in the omitted case of accounting documents. A dental implant cost by top-down method was estimated to 1,430,000 won. Labor cost accounted for 43% of the total cost structure, ranking it 1st and, management cost, material cost and interest cost on investment cost in order are investigated. Labor cost counts of the total cost that shows the similar aspect to the existing result. Cost in cost accounting of medical care would be used for the judge that cost pursed value for dental service, not price or fee.

• Journal of Electrochemical Science and Technology
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• 제15권3호
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• pp.345-352
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• 2024

The synthesis of Pt nanoparticles and catalytically active materials using the electrochemical top-down approach involves dispersing Pt electrodes in an electrolyte solution containing alkali metal cations and support material powder using an alternating pulsed current. Platinum is dispersed to form particles with a predominant crystallographic orientation of Pt(100) and a particle size of approximately 7.6±1.0 nm. The dispersed platinum particles have an insignificant content of PtO_x phase (0.25±0.03 wt.%). The average formation rate was 9.7±0.5 mg cm^-2 h^-1. The nature of the support (carbon material, metal oxide, carbon-metal oxide hybrid) had almost no effect on the formation rate of the Pt nanoparticles as well as their crystallographic properties. Depending on the nature of the support material, Pt-containing catalytic materials obtained by the electrochemical top-down approach showed good functional performance in fuel cell technologies (Pt/C), catalytic oxidation of CO (Pt/Al₂O₃) and electrochemical oxidation of methanol (Pt/TiO₂-C) and ethanol (Pt/SnO₂-C).

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.2419-2423
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• 2012

Context: Genuine community participation does not denote taking part in an action planned by health care professionals in a medical or top-down approach. Further, community participation and health education on breast cancer prevention are not similar to other activities incorporated in primary health care services in Iran. Objective: To propose a model that provides a methodological tool to increase women's participation in the decision making process towards breast cancer prevention. To address this, an evaluation framework was developed that includes a typology of community participation approaches (models) in health, as well as five levels of participation in health programs proposed by Rifkin (1985&1991). Method: This model explains the community participation approaches in breast cancer prevention in Iran. In a 'medical approach', participation occurs in the form of women's adherence to mammography recommendations. As a 'health services approach', women get the benefits of a health project or participate in the available program activities related to breast cancer prevention. The model provides the five levels of participation in health programs along with the 'health services approach' and explains how to implement those levels for women's participation in available breast cancer prevention programs at the local level. Conclusion: It is hoped that a focus on the 'medical approach' (top-down) and the 'health services approach' (top-down) will bring sustainable changes in breast cancer prevention and will consequently produce the 'community development approach' (bottom-up). This could be achieved using a comprehensive approach to breast cancer prevention by combining the individual and community strategies in designing an intervention program for breast cancer prevention.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.454-457
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• 1996

In this paper, a two-stage and top-down approach of mid-term and long-term R&D planning of public corporation is proposed to incorporate some characteristics of public corporation and to overcome the complexity of the real world planning. Unlikely to R&D planning of private company, the total investiment size of public corporation is institutionally determined. A top-down approach is developed to adopt this feature. The proposed approach has two stages to overcome the complexity. In the first stage, we develop a plan for R&D area by adopting the business area and the public role of corporation. In the second stage, we develop the detailed plan within each area. The proposed approach is applied to develop the mid-term and long-term R&D plan of Korea Gas Corporation.

• Perspectives in Nursing Science
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• 제13권2호
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• pp.81-87
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• 2016

Purpose: The aim of this study is to review the nurse demand forecasting methods in empirical studies published during 1991~2014 and suggest ideas to improve the validity in nurse demand forecasting. Methods: Previous studies on nurse demand forecasting methodology were categorized into four groups: time series analysis, top-down approach of workforce requirement, bottom-up approach of workforce requirement, and labor market analysis. Major methodological properties of each group were summarized and compared. Results: Time series analysis and top-down approach were the most frequently used forecasting methodologies. Conclusion: To improve decision-making in nursing workforce planning, stakeholders should consider a variety of demand forecasting methods and appraise the validity of forecasting nurse demand.

• 한국정밀공학회지
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• 제21권6호
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• pp.153-159
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• 2004

In this study, a new process to pattern directly on a thin metal layer using improved nano replication printing (nRP) process is suggested to evaluate the possibilities of fabricating a stamp for nano-imprinting. In the nRP process, any figure can be replicated from a bitmap figure file in the range of several micrometers with nano-scaled details. In the process, liquid-state resins are polymerized by two-photon absorption which is induced by femto-second laser. A thin gold layer was sputtered on a glass plate and then, designed patterns or figures were developed on the gold layer by newly developed top-down building approach. Generally, stamps fur nano-imprinting have been fabricated by using the costly electron-beam lithography process combined with a reactive ion-etching process. Through this study, the effectiveness of the improved nRP process is evaluated to make a stamp with the resolution of around 200nm with reduced cost.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
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• pp.15-19
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• 2001

Creating an artificial strain with a minimal gene set for a specific purpose is every biologist's dream. With the complete genome sequencing of more than 50 microorganisms and extensive functional analyses of their genes, it is possible to design a genetic blueprint for a simple custom-designed microbe with the minimal gene set. Two different approaches are being considered. The first 'top-down' approach is trimming the genome to a minimal gene set by selectively removing genes of an organism thought to be unnecessary based on microbial genomics. The second 'bottom-up' approach is to synthesize the proposed minimal genome from basic chemical building blocks. The 'top-down' approach starting with the genome of a well known microorganism is more technically feasible, whereas the bottom-up approach may not be attainable in the nearest future because of the lack of the complete functional analysis of the genes needed for a life. Here in this study, we used the top-down approach to minimize the E. coli genome to create an artificial organism with 'core' elements for self-sustaining and self-replicating cells by eliminating unnecessary genes. Using several different kinds of sophisticated deletion techniques combined with a p:1age and transposons, we deleted about 19％ of the E. coli genome without causing any damages to cellular growth. This smaller E. coli genome will be further reduced to a genome with a minimal gene l;et essential for cell life. This minimized E. coli genome can lead to the construction of many custom-designed strains with myriad practical and commercial applications.