• Journal of the Korean Society of Visualization
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• v.9 no.4
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• pp.16-21
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• 2011

The effects of stroke change on turbulent kinetic energy for the in-cylinder flow of a four-valve SI engine were studied. For this study, the same intake manifold, head, cylinder, and the piston were used to examine turbulence characteristics in two different strokes. In-cylinder flow measurements were conducted using three dimensional LDV system. The measurement method, which simultaneously collects 3-D velocity data, allowed a evaluation of turbulent kinetic energy inside a cylinder. High levels of turbulent kinetic energy were found in regions of high shear flow, attributed to the collisions of intake flows. These specific results support the more general conclusion that the inlet conditions play the dominant role in the generation of the turbulence fields during the intake stroke. However, in the absence of two counter rotating vortices, this intake generated turbulent kinetic energy continues to decrease but at a much faster rate.

• International Commerce and Information Review
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• v.5 no.1
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• pp.103-121
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• 2003

Nowadays, the spread of electronic commerce using internet demands a large changes doing business with company to company and give that company a change to recognize logistics. To support logistics activity, all kinds of companies are using the computer and are recognized that the efficient using of Cyber Logistics Information will mainly play a roll to strength the companies competition power. Accordingly, the purpose of this study is to suggest the following plans, the first plan is to research the companies which is offering the logistics information on the Web site based on the internet and to investigate the contents of Logistics Information, then the second plan is to give companies which is to get the logistics information on Internet, more efficient ways using internet based logistics information systems.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.89-92
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• 2000

In this paper, we consider the interworking methods for Internet layer 3 protocols. The legacy protocol for Internet is IPv4(IP version 4). The ability of IPv4 is not enough for modern real time multimedia communication services. So IPv6(IP version 6) protocol was suggested to resolve the problems of IPv4. 6Bones(IPv6 Backbones) have also constructed from 1996 in many countries. The 6Bones should be interoperatable to the legacy internet. To support all data services including voice and video, IP protocol should be enhanced because the characteristics of modern network services are requiring QoS(Quality of Service) functions, plug and play, security, mobility and so on. So a new IP protocol, IPv6, has been developing to meet the requirements. In this paper, some migration methods for internets are described. We first describe the protocol compatibility problems and suggest some solutions and scenario to solve the problems.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.403.2-403.2
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• 2016

Porous materials play a significant role in energy storage and conversion applications such as catalyst support for polymer electrolyte membrane fuel cell. In particular, hierarchical porous materials with both micropores (poresize, ${\delta}$ < 2 nm) and regularly arranged mesopores (2 nm < ${\delta}$ < 50 nm) are known to greatly enhance the efficiency of catalytic reactions by providing enormous surface area as well as fast mass transport channels for both reactants and products from/to active sites. Although it is generally agreed that the microscopic structure of the porous materials directly affects the performance of these catalytic reactions, neither detailed mechanisms nor fundamental understanding are available at hand. In this study, we propose an atomistic model of hierarchical nanostructured porous carbons (HNPCs) in molecular dynamics simulations. By performing a systematic study, we found that structural features of the HNPC can be independently altered by tuning specific synthesis parameters, while remaining other structures unchanged. In addition, we show some structure-property relations including mechanical and gas transport properties.

• The Journal of the Korean dental association
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• v.53 no.5
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• pp.307-317
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• 2015

Although the long-term success of osseointegrated endosseous implants for the support of fixed dental prostheses has been reported, the increasingly widespread use of implant-supported prostheses has led to problems associated with their structural integrity. The most common biomechanical complications observed in dental implant treatment are fracture and screw loosening. The nature of loosening or fracture of dental implant components is complex, since it involves fatigue, fitness, and varied chewing patterns and loads. To assess the service life of the components of the prosthetic system, a knowledge of the loads transmitted through the system is necessary. Design of the final restoration and occlusion in relation to the geometry of a prosthetic restoration has a great influence on the mechanical loading of the implant. It is proposed that control of force in oral cavity may play a larger role in failures than previously believed. Based on theoretic consideration and clinical experiences with dental implant, this article gives simple guidelines for controlling these loads.

• Proceedings of the Korea Association of Information Systems Conference
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• 2000.05a
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• pp.53-63
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• 2000

의사결정 지원을 위해 각광받고 있는 데이터 웨어하우스 시스템은 주제 지향적, 통합적, 시계열적, 비휘발적인 데이터 저장공간을 보유하여 사용자가 쉽게 데이터에 접근하여 원하는 분석을 수행할 수 있도록 도와주는 고품질의 정보제공 시스템이다. 본 논문에서는 구체적인 데이터 웨어하우스 시스템을 소개함에 있어 국내 병원의 건강진단 데이터 웨어하우스 시스템 프로토타입 개발을 시도한다. 이에 데이터 웨어하우스 시스템의 구성에 대해 살펴본 후, 데이터 웨어하우스 시스템 개발 툴인 Cognos사의 PowerPlay를 이용하여 건강진단 데이터 웨어하우스 시스템 개발을 시도하고, 그 구축 방법과 결과를 소개한다.

• 한국경영정보학회:학술대회논문집
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• 2007.11a
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• pp.123-128
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• 2007

It has been argued that Enterprise systems (ES) implementations are overshadowed by a high failure rate despite their promised benefits. One of the commonly cited reasons for ES implementation failures in the context of mandatory use is end-user's unwillingness or sabotage to adopt or use systems. Considering that the appropriate management of expectations may play an important role in making positive behavior toward newly implemented systems, this study examines the effect of outcome expectations on the system use activity in the mandatory use context of information systems from the Social Cognitive Theory perspective. Structural equation model analysis using LISREL 8.7 provides significant support for the proposed relationships. The empirical results suggest that outcome expectations and user satisfaction have positive effects on system use activity conceptualized by immersion, reinvention, and learning. Theoretical and practical implications of the study shed some light on how to improve system use activity in the mandatory use context of information systems.

• Journal of KSNVE
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• v.11 no.3
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• pp.471-476
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• 2001

This paper focuses on the numerical prediction of airflow-induced sound in DVD drives. As a first step, computational fluid dynamics (CFD) is conducted to evaluate flow field characteristics due to the high-speed disk rotation, and to support the acoustic analysis. Acoustic analogy based on Ffowcs Wi1liams-Hawkings (FW-H) equation is adopted to predict aeroacoustic noise patterns. The integral solution for quadrupole volume source is included to identify the turbulence noise generated inside the DVD tray. The strength of sound pressure revel with respect to rotating speed is discussed to meet upfront demand on the high fidelity product development. The present study also focuses on the noise directivity and examines how much the sound noise is sensitive to change in rotating speed. Near-field noise is strongly affected by the flow field characteristic, which is caused by the complex shape of the tray. For a mid-field, the quadrupole noise play as a counterpart of thickness noise or loading noise, so it generates different sound noise Patterns compared with those in the near field.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.16-22
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• 2001

There is no doubt that agents play an increasingly predominant role in e-commerce, whether these are business-to-consumer or business-to-business applications. However most of the current e-commerce agents only support a single bid for a product at a fixed price. Although price is an important factor, it is not the only concern of both business and consumer. There is doubt as to whether such agents satisfv both parties. Negotiation on a variety of issues is needed in order to reach an agreement. In this paper, a computational agent negotiation(CAN) model is proposed to facilitate multiple-issue negotiation via an agent. The main contribution of the CAN model is it enables agent to participate actively in the negotiation with various feedback instead of simply an agreement or rejection.

• Journal of Nutrition and Health
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• v.28 no.7
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• pp.636-643
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• 1995

This study was conducted to find some differences in infant feeding pattems between well educated Koreans and local populations living in Texas, USA. Initiation rate of exclusive breastfeeding in the hospital was 35.9% in Koreans and 60.4% in Americans. At 2, 4 and 6 months, exclusive breastfeeding rates were 34.0%, 20.8% and 13.2% for Koreans and 47.2%, 34.0% and 27.2% for Americans respectively. There was a significant difference in age of weaning from breast between these two groups(p<0.01). In Koreans the most common reason for the early termination before 4 months was maternal report of milk insufficiency. 55.6% of Koreans and 42.3% of Americans fed infants on scheduled rather on demand feeding. Primary sources of advice about feeding were medical professionals in Americans while baby's grandmother was the main source in Koreans. In Americans, choice of breastfeeding was not associated with ethnicity, maternal education, and family income in the study. Interventions to promote and support participants of Women Infants and Children(WIC) may play a role in Americans. It might be suggested that effective nutrition education programs targeting for Korean mothers to promote breastfeeding should be needed urgently and systematically.