• Journal of Information Technology Applications and Management
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• 제24권3호
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• pp.93-105
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• 2017

Demands of cosmetics are affected not only by the well-known elements such as brand, price, and customer's consumption capacity, but also by some latent factors, for example, weather and air environment. Due to complexity and dynamic changes of the above factors, their influences can hardly be estimated in an accurate way by the traditional approaches such as survey and questionnaires. Through modeling and statistical analysis of big data, this article studied the impacts of weather condition and air quality on customer flow and sales of the cosmetics distributors in China, and found several hidden influencing factors. It provided a big-data based method for the analysis of unconventional factors on cosmetics marketing in the changing weather condition and air environment.

• Journal of Power Electronics
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• 제2권4호
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• pp.240-249
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• 2002

Power electronics Is an emerging technology New applications are added every year as well as the power handling capabilities are steadily increasing. The demands to the education of engineers in this field are also increasing. Basically the content of the curriculum should be more expanded without extra study time. This paper present a teaching approach which makes it possible very fast for the student to get in-deplh skills in this important area which is the problem-oriented and project-based learning. The trend and application of power electronics are illustrated. The necessary skills for power electronic engineers are outlined followed up by a discussion on how problem-oriented and project-based learning are implemented. A complete curriculum at Aalborg University is presented where different power electronics related projects at different study levels are carried out.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.413-418
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• 2004

Recently, the development of mobile devices demands information storage systems to use micro drive devices. 1-inch micro drive hard disk uses the load/unload(L/UL) technology to increase area recording density and reduce power consumption. Because micro drive has light actuator, effects of the flexible cable that is ignored in 3.5-inch hard disk drive is important to load/unload performances. In this paper, effects of flexible cable on load/unload performances are studied.

• 한국지진공학회논문집
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• 제23권1호
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• pp.83-88
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• 2019

Structural analysis remains as an essential part of any integrated civil engineering system in today's rapidly changing computing environment. Even with enormous advancements in capabilities of computers and mobile tools, enhancing computational efficiency of algorithms is necessary to meet the changing demands for quick real time response systems. The finite element method is still the most widely used method of computational structural analysis; a robust, reliable and automated finite element structural analysis module is essential in a modern integrated structural engineering system. To be a part of an automated finite element structural analysis, an efficient adaptive mesh generation scheme based on R-H refinement for the mesh and error estimates from representative strain values at Gauss points is described. A coefficient that depends on the shape of element is used to correct overly distorted elements. Two simple case studies show the validity and computational efficiency. The scheme is appropriate for nonlinear and dynamic problems in earthquake engineering which generally require a huge number of iterative computations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• Wind and Structures
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• 제32권5호
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• pp.501-508
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• 2021

The turbine industry demands a reliable design with affordable cost. As technological advances begin to support turbines of huge sizes, and the increasing importance of wind turbines from day to day make design safety conditions more important. Wind turbines are exposed to environmental conditions that can affect their installation, durability, and operation. International Electrotechnical Commission (IEC) 61400-1 design load cases consist of analyses involving wind turbine operating conditions. This design load cases (DLC) is important for determining fatigue loads (i.e., forces and moments) that occur as a result of expected conditions throughout the life of the machine. With the help of FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open source software, the NREL 5MW land base wind turbine model was used. IEC 61400-1 wind turbine design standard procedures assessed turbine behavior and fatigue damage to the tower base of dynamic loads in different design conditions. Real characteristic wind speed distribution and multi-directional effect specific to the site were taken into consideration. The effect of these conditions on the economic service life of the turbine has been studied.

• ETRI Journal
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• 제42권6호
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• pp.846-858
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• 2020

The non-orthogonal multiple access (NOMA) technique offers throughput improvement to meet the demands of the future generation of wireless communication networks. The objective of this work is to further improve the throughput by including an underlay cognitive radio network with an existing multi-carrier NOMA network, using cooperative communication. The throughput is maximized by optimal resource allocation, namely, power allocation, subcarrier assignment, relay selection, user pairing, and subcarrier pairing. Optimal power allocation to the primary and secondary users is accomplished in a way that target rate constraints of the primary users are not affected. The throughput maximization is a combinatorial optimization problem, and the computational complexity increases as the number of users and/or subcarriers in the network increases. To this end, to reduce the computational complexity, a dynamic network resource allocation algorithm is proposed for combinatorial optimization. The simulation results show that the proposed network improves the throughput.

• 기술혁신연구
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• 제12권2호
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• pp.151-183
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• 2004

This paper investigates the evolution of 'inter-firm' technology transfer in the Thai automobile industry, which has gradually been integrated into global production network of some specific automotive models(one-ton pickups). This paper discusses the linkage between the role of automobile assemblers in transferring technology and the way their strategic changes bring about heightened demands on the technological capacity of suppliers and the contents of technology transfer. With higher competition at the global level, local suppliers are required to improve their technical and managerial skills, especially in the area of 'product engineering' capability. The authors examine the ways local firms have adapted to these changes in their environments, as well as the ways they utilize inter-firm relationship with automobile assemblers as a means to improve their own technological capabilities. The dynamic process of capability formation in local parts firms, through intensive efforts and learning inducements brought about by inter-firm relationships, are also discussed.

• 전자통신동향분석
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• 제38권3호
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• pp.20-28
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• 2023

Wireless communication technology has mainly been used to fulfill the demands of industrial sites at which performance is not a critical concern. However, ongoing discussions and efforts are now focused on securing core wireless communication technologies to enable the transformation or expansion of wired industrial IoT (Internet of Things) network technology into a flexible and dynamic smart manufacturing system. This paper provides an overview of current wireless industrial IoT network technology and the recent wireless time-sensitive networking technology. It outlines the challenging level of reliability required for wireless communication technology to coexist with or replace its wired counterpart in future smart manufacturing systems. Additionally, we introduce ultra-reliable time deterministic network as the core technology of wireless industrial communications and focus on its reliability and delay characteristics.

• 한국전산구조공학회논문집
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• 제28권1호
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• pp.29-37
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• 2015

본 연구에서는 BWIM(Bridge Weigh-in-Motion) 시스템을 기반으로 주행차량의 총중량 및 축중량 추정을 수행하였다. BWIM 시스템의 개발을 위해 차량 주행시험은 필수적이지만 그 비용과 시간이 많이 소요되고, 다양한 차량 주행 조건의 적용이 어렵다. 따라서 차량 주행시험의 비용 및 시간적 문제점을 보완하고, 주행 조건에 따른 다양한 교량응답의 확보할 수 있는 수치 시뮬레이션이 현장실험과 병행되어야한다. 본 연구에서는 교량의 동적특성을 반영하는 수치 시뮬레이션을 수행하여 교량의 응답을 획득하고, 통행 차량의 중량을 산출하는 BWIM 시스템에 적용하여 총중량 및 축중량 추정을 수행하고 정밀해석모델기반 과적단속기술에 대하여 제안하였다.