• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.352-359
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• 2010

In recent years, the market has shown increasing interest in pump-turbines. The prompt availability of pumped storage plants and the benefits to the power system achieved by peak lopping, providing reserve capacity, and rapid response in frequency control are providing a growing advantage. In this context, there is a need to develop pumpturbines that can reliably withstand dynamic operation modes, fast changes of discharge rate by adjusting the variable diffuser vanes, as well as fast changes from pumping to turbine operation. In the first part of the present study, various flow patterns linked to operation of a pump-turbine system are discussed. In this context, pump and turbine modes are presented separately and different load cases are shown in each operating mode. In order to create modern, competitive pump-turbine designs, this study further explains what design challenges should be considered in defining the geometry of a pump-turbine impeller. The second part of the paper describes an innovative, staggered approach to impeller development, applied to a low head pump-turbine project. The first level of the process consists of optimization strategies based on evolutionary algorithms together with 3D in-viscid flow analysis. In the next stage, the hydraulic behavior of both pump mode and turbine mode is evaluated by solving the full 3D Navier-Stokes equations in combination with a robust turbulence model. Finally, the progress in hydraulic design is demonstrated by model test results that show a significant improvement in hydraulic performance compared to an existing reference design.

• ETRI Journal
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• 제35권1호
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• pp.7-17
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• 2013

The ongoing proliferation of new services, applications, and contents is leading the Internet to an architectural crisis owing to its inability to provide efficient solutions to new requirements. Clean-slate architectures for the future Internet offer a new approach to tackle current and future challenges. This proposal introduces a novel clean-slate architecture in which the TCP/IP protocol stack is decoupled in basic functionalities, that is, atomic services (ASs). A negotiation protocol, which enables context-aware service discovery for providing adapted communications, is also specified. Then, we present how ASs can be discovered and composed according to requesters' requirements. In addition, a media service provisioning use case shows the benefits of our framework. Finally, a proof-of-concept implementation of the framework is described and analyzed. This paper describes the first clean-slate architecture aligned with the work done within the ISO/IEC Future Network working group.

• 한국IT서비스학회지
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• 제12권1호
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• pp.173-187
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• 2013

The advent of Web2.0 has believed to be the solution against many barriers in information sharing, especially wiki. Information sharing and collaboration are realized voluntarily and unselfishly with wiki. The purpose of this paper is to analyze the benefits and challenges of using wiki as a project management method in an IT/IS project. Wiki-based project management could provide project managers and members with expert knowledge collaboration for better project results. In the research model, we used TMS(Transactive Memory System) theory to define the relation of collaboration and performance of project members. Based on a survey among project members, the interactions between wiki characteristics and performance are examined in an IS project environment. Using Smart PLS 2.0, the data was analyzed to define the interactions by the structural equation modeling. From the empirical data, the mediated effect of expert knowledge collaboration is supported. We also derive the implications of wiki-based method. It is expected to bring new possibilities of Project management performance.

• 산경연구논집
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• 제11권11호
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• pp.7-18
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• 2020

Purpose: The Emission Trading Scheme (ETS), which enables structuring emission credits as a financial product, is taking a crucial position of global collaboration against climate change. Previous studies that have covered ETS subjects from the macro perspective contribute to facilitating legal enactment of this scheme. However, they have rarely addressed challenges aligned with issues arising from labor burdens for ETS works from the business perspective. Research Design, data and methodology: This study presents conceptual models that are expected to help design an electronic system. The study model contains four modules: emission allocation, data interface, reduction technology sharing, and emission trading. Two validation approaches, the Analytic Hierarchy Process (AHP) and regression analysis, are applied in confirming the feasibility of the proposed model. Results: This study suggests an IT system methodology to help improvement of the current K-ETS mechanism. In particular, this study addresses effectiveness for real businesses and the adaptability of this mechanism to other nations. Conclusions: The proposed IT platform diagram can contribute to successful operation of ETS by providing multiple benefits to participating companies through in-house allocation mechanisms, the soft-landing of ETS adoption to participating companies through reduction of technology-sharing, group purchases, and transaction costs through the trading system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권3호
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• pp.266-284
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• 2009

The challenges of rapidly growing numbers of mobile nodes in IPv6-based networks are being faced by mobile computing researchers worldwide. Recently, IETF has standardized Mobile IPv6 and Fast Handover for Mobile IPv6(FMIPv6) for supporting IPv6 mobility. Even though existing literatures have asserted that FMIPv6 generally improves MIPv6 in terms of handover speed, they did not carefully consider the details of the whole handover procedures. Therefore, in conventional protocols, the handover process reveals numerous problems manifested by a time-consuming network layer based movement detection and latency in configuring a new care of address with confirmation. In this article, we study the impact of the address configuration and confirmation procedure on the IP handover latency. To mitigate such effects, we propose a new scheme which can reduce the latency taken by the movement detection, address configuration and confirmation from the whole handover latency. Furthermore, a mathematical analysis is provided to show the benefits of our scheme. In the analysis, various parameters are used to compare our scheme with the current procedures, while our approach is focused on the reduction of handover latency. Finally, we demonstrate total handover scenarios for the proposed techniques and discussed the major factors which contribute to the handover latency.

• 한국동물위생학회지
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• 제32권1호
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• pp.87-92
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• 2009

The avoidance of the allergen of the house dust mite is one of the challenges to reduce and treat the symptoms of allergic diseases. Accordingly, various acaricidal agents are being used to kill the mite, but just killing it leaves the remains of it, which still act as the allergen. Therefore expelling the mite is thought as best policy to avoid the mite allergen. For this, some materials have been applied to repellent agents against the mite. Among them, a material with natural origin, known as the phytoncide, is being used for its repellent activity, as well as for its benefits for health. In this experiment, essential oils extracted from Korean white pine (Pinus koreaiensis S. et Z.) and hinoki cypress (Chamaecyparis obtusa), which are widely used as the source of phytoncide products, are studied for demonstration of the repellent effect against the house dust mites, Dermatophagoides farinae and D. pteronyssinus. Direct contact method was used to evaluate the repellent effect (%). And the results suggest the oils have a significant effect enough to be used as a source of repellent agent. For the repellent effect, the most effective concentration was $0.5{\mu}l/cm^2$ at 45 minutes both in the white pine and the hinoki oil.

• 한국연초학회:학술대회논문집
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• 한국연초학회 1997년도 담배과학 국제학술대회
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• pp.114-133
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• 1997

담배향료 기술(Cigarette flavor technology)은 향료 전문가에게는 여러 중요한 요소들을 필요로하는 분야이다. 제조담배의 끽미 특성이 어떻게 발현되는지 알기 위해서는 담배향료의 역사에 관해 이해하는 것이 필요하다. Casings 및 top flavors를 가향료로 사용하는 담배제조 분야에 대해서 검토하고, 담배향료에 대한 법적인 규제의 중요성과 이들 법규가 미래에 어떤 영향을 줄 것인지에 대해서도 토론할 것이다. 여러 가지 형태의 casing류의 장점과 함께 casing sauce로 사용되는 향료성분들을 설명하고 현재 사용되는 top flavor와 top flavor와 관련된 앞으로의 전망에 대해서도 토론할 것이다. 새로운 가향기술(flavor technology)과 그 기술이 제조담배 생산에 미치는 영향은 담배향료 전문가들에게 새로운 도전이 될 것이다.

• 디지털융복합연구
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• 제21권3호
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• pp.41-48
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• 2023

제4차 산업혁명이 확대되면서 국가경제의 미래와 관련한 새로운 불확실성에 직면하게 되었다. 디지털 전환(DX)이 오늘날 ICT 중심 세계에서 필수적인 글로벌 패러다임이다. 공신력있는 글로벌 보고서들에 따르면 한국은 이미 글로벌 제조업 부가가치(MVA)에서 큰 비중을 차지하고 있으며, 향후 그 비중을 확대할 수 있는 좋은 위치에 있다. 본 논문에서는 디지털 전환에 초점을 맞추어 한국 경제의 글로벌 경쟁력 수준을 측정하고자 시도한다. 우선 세계적으로 인정받는 분석들을 참조하여 국가경쟁력을 비교해 봤다. 산업과 경제가 또 다른 기술 혁명의 직면한 만큼 각국은 변화하는 산업의 추세에 대한 인식을 구축하고, 이러한 변혁의 혜택을 받을 수 있는 최선의 준비 방법을 결정하여 준비태세를 강화해야 한다. 제4차 산업혁명 시대의 디지털화의 기회와 정책 과제를 분석해 보기로 하였다.

• 통합자연과학논문집
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• 제4권2호
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• pp.149-157
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• 2011

Urbanization of the world's population has given rise to more than 450 cities around the world with populations in excess of 1 million (megacity) and more than 25 so-called metacities with populations over 10 million (Brinkhoff, 2010). The United States today has a total resident population of more than 308,500,000 people, with 81 percent residing in cities and suburbs as of mid - 2005 (UN, 2008). Urban meteorology is the study of the physics, dynamics, and chemistry of the interactions of Earth's atmosphere and the urban built environment, and the provision of meteorological services to the populations and institutions of metropolitan areas. While the details of such services are dependent on the location and the synoptic climatology of each city, there are common themes, such as enhancing quality of life and responding to emergencies. Experience elsewhere (e.g., Shanghai, Helsinki, Tokyo, Seoul, etc.) shows urban meteorological support is a key part of an integrated or multi-hazard warning system that considers the full range of environmental challenges and provides a unified response from municipal leaders. Urban meteorology has come to require much more than observing and forecasting the weather of our cities and metropolitan areas. Forecast improvement as a function of more and better observations of various kinds and as a function of model resolution, larger ensembles, predicted probability distributions; Responses of emergency managers, government officials, and users to improved and probabilistic forecasts; Benefits of improved forecasts in reduction of loss of life, property damage, and other adverse effects. A national initiative to enhance urban meteorological services is a high-priority need for a wide variety of stakeholders, including the general, commerce and industry, and all levels of government. Some of the activities of such an initiative include: conducting basic research and development; prototyping and other activities to enable very--short and short range predictions; supporting and improving productivity and efficiency in commercial and industrial sectors; and urban planning for long term sustainability. In addition urban test-beds are an effective means for developing, testing, and fostering the necessary basic and applied meteorological and socioeconomic research, and transitioning research findings to operations. An extended, multi-year period of continuous effort, punctuated with intensive observing and forecasting periods, is envisioned.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.47-47
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• 2010

Over the past 20 years, constant progress in noise and vibration (NVH) engineering has enabled to constantly advance quality and comfort of operation and use of really any products - from automobiles to aircraft, to all kinds of industrial vehicles and machines - to the extend that for many products, supreme NVH performance has becomes part of its brand image in the market. At the same time, the product innovation agenda in the automotive, aircraft and really many other industries, has been extended very much in recent years by meeting ever more strict environmental regulations. Like in the automotive industry, the drive towards meeting emission and CO2 targets leads to very much accelerated adoption of new powertrain concepts (downsizing of ICE, hybrid-electrical...), and to new vehicle architectures and the application of new materials to reduce weight, which bring new challenges for not only maintaining but further improving NVH performance. This drives for innovation in NVH engineering, so as to succeed in meeting a product brand performance for NVH, while as the same time satisfying eco-constraints. Product innovation has also become increasingly dependent on the adoption of electronics and software, which drives for new solutions for NVH engineering that can be applied for NVH performance optimization of mechatronic products. Finally, relentless pressure to shorten time to market while maintaining overall product quality and reliability, mandates that the practice and solutions for NVH engineering can be optimally applied in all phases of product development. The presentation will first review the afore trends for product and process innovation, and discuss the challenges they represent for NVH engineering. Next, the presentation discusses new solutions for NVH engineering of products, so as to meet target brand values, while at the same time meeting ever more strict eco constraints, and this within a context of increasing adoption of electronics and controls to drive product innovation. NVH being very much defined by system level performance, these solutions implement the approach of "Model Based System Engineering" to increase the impact of system level analysis for NVH in all phases of product development: - At the Concept Phase, to be able to do business case analysis of new product concepts; to arrive at an optimized and robust product architecture (e.g. to hybrid powertrain lay-out, to optimize fuel economy); to enable target cascading, to subsystem and component level. - In Development Phase, to increase realism and productivity of simulation, so as to frontload virtual validation of components and subsystems and to further reduce reliance on physical testing. - During the final System Testing Phase, to enable subsystem testing by a combination of physical testing and simulation: using simulation models to simulate the final integration context when testing a subsystem, enabling to frontload subsystem testing before final system integration is possible. - To interconnect Mechanical, Electronical and Controls engineering, in all phases of development, by supporting model driven controls engineering (MIL, SIL, HIL). Finally, the presentation reviews examples of how LMS is implementing such new applications for NVH engineering with lead customers in Europe, Asia and US, with demonstrated benefits both in terms of shortening development cycles, and/or enabling a simulation based approach to reduce reliance on physical testing.