• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.177-186
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• 2000

An improved multi-level（IML) optimization algorithm using automatic differentiation (AD) for multi-objective optimum design of framed structures is proposed in this paper. In order to optimize the steel frames under seismic load, two main objective functions need to be considered for minimizing the structural weight and maximizing the strain energy. For the efficiency of the proposed algorithm, multi-level optimization techniques using decomposition method that separately utilizes both system-level and element-level optimizations and an artificial constraint deletion technique are incorporated in the algorithm. And also to save the numerical efforts, an efficient reanalysis technique through approximated structural responses such as moments, frequencies, and strain energy with respect to intermediate variables is proposed in the paper. Sensitivity analysis of dynamic structural response is executed by AD that is a powerful technique for computing complex or implicit derivatives accurately and efficiently with minimal human effort. The efficiency and robustness of the IML algorithm, compared with a plain multi-level (PML) algorithm, is successfully demonstrated in the numerical examples.

• 센서학회지
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• 제22권6호
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• pp.421-427
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• 2013

In this paper, we introduce a new synchronous visible light communication system in which the synchronizing pulse and the data bits are simultaneously transmitted using a 3-level light signal. In the transmitter, the synchronizing pulse and the data bits modulate independently two identical visible LEDs, whose output lights add in free space, make 3-level optical signal. In the receiver, a photodiode detects the light and generates a 3-level output voltage, whose positive and negative part correspond to the synchronizing pulse and the data bits, respectively. The two signals are easily separated and recovered by a simple diode circuit. This configuration provides two independent VLC channels without any multiplexing technique, simplifies the circuit design and construction of synchronous VLC systems.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.140-141
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• 2018

Protective coatings at nuclear power plants should be designed to withstand exposure to ambient conditions during normal operation or design-basis accidents. However, there was a change in the perception of the protective coating to the revision of the Regulatory Guidelines by the NRC in July 2000. In other words, maintenance guidelines have been strengthened in order to minimize the clogging of the cooling water system due to the substances in the containment building. Therefore, KHNP, the contractor and operator of the nuclear power plant, plans to develop the coating system for nuclear power plants in accordance with the regulation, and plans to develop its own coating expert.

• 산업경영시스템학회지
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• 제28권3호
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• pp.109-114
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• 2005

The founding purpose of Business Incubation System is to induce those businessmen who have technology and promising business ideas but are lacking fund, information, and management skill, and to speed up their business establishment and enhance the level of success by providing them with managerial knowledge, production technology, design, and equipment. While some universities made Business Incubation Center to achieve the above purpose, some other universities, especially the local ones, believed that Business Incubation Center, if managed successfully, could be an accelerator picking up the sluggish local economies. This study studied the motivators that let them move in an Incubating Center, their request for support, their level of expert utilization, and the role of head of a Center. This study found a significant level of correlation among the variables such as industrial-educational cooperation, the development of common items, utilization of professors with matching majors, utilization of research professors, and transfer of technology.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.82.3-82
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• 2001

This work presents a design technique for the implementation of the liquid level control system by based on the use of a single-chip microcontroller. The proposed model system offers the following attractive features : (1) application of the pressure transducer for sensing the height of liquid in tank (2) using the obtained liquid level for defining on-off condition of the water pump (3) the liquid values were controlled by using stepping motors for controlling of 57 points (4) can set up by using manual control or automatic control (5) can monitor and display the process status either on microcontroller-based control board or on the computer via RS232 serial-port. Experimental results have been employed to show the effectiveness ...

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1373-1392
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• 2017

WiFi Direct (WD) is a state of the art technology for a Device-to-Device (D2D) communication in 802.11 networks. The performance of the WD system can be significantly affected by some key factors such as the type of application, specifications of MAC and PHY layer parameters, and surrounding environment etc. It is, therefore, important to develop a system model that takes these factors into account. In this paper, we focus on investigating the design parameters of the PHY layer that could maximize the efficiency of the WD 802.11 system. For this purpose, a basic theoretical model is formulated for a WD network under a 2x2 Multiple In Multiple Out (MIMO) TGn channel B model. The design level parameters such as input symbol rate and antenna spacing, as well as the effects of the environment, are thoroughly examined in terms of path gain, spectral density, outage probability and Packet Error Rate (PER). Thereafter, a novel adaptive algorithm is proposed to choose optimal parameters in accordance with the Quality of Experience (QoE) for a targeted application. The simulation results show that the proposed method outperforms the standard method thereby achieving an optimal performance in an adaptive manner.

• 마이크로전자및패키징학회지
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• 제19권2호
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• pp.29-33
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• 2012

The demand for 3D wafer level integration has been increasing significantly. Although many technical challenges of wafer stacking are still remaining, wafer stacking is a key technology for 3D integration due to a high volume manufacturing, smaller package size, low cost, and no need for known good die. Among several new process techniques Cu-to-Cu wafer bonding is the key process to be optimized for the high density and high performance IC manufacturing. In this study two main challenges for Cu-to-Cu wafer bonding were evaluated: misalignment and bond quality of bonded wafers. It is demonstrated that the misalignment in a bonded wafer was mainly due to a physical movement of spacer removal step and the bond quality was significantly dependent on Cu bump dishing and oxide erosion by Cu CMP.

• Geomechanics and Engineering
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• 제16권4호
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• pp.449-461
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• 2018

The load sharing ratio (${\alpha}_{pr}$) of piles is one of the most common problems in the preliminary design of piled raft foundations. A series of 3D numerical analysis are conducted so that special attentions are given to load sharing characteristics under varying conditions, such as pile configuration, pile diameter, pile length, raft thickness, and settlement level. Based on the 3D FE analysis, influencing factors on load sharing behavior of piled raft are investigated. As a result, it is shown that the load sharing ratio of piled raft decreases with increasing settlement level. The load sharing ratio is not only highly dependent on the system geometries of the foundation but also on the settlement level. Based on the results of parametric studies, the load sharing ratio is proposed as a function of the various influencing factors. In addition, the parametric analyses suggest that the load sharing ratios to minimize the differential settlement of piled raft are ranging from 15 to 48% for friction pile and from 15 to 54% for end-bearing pile. The recommendations can provide a basis for an optimum design that would be applicable to piled rafts taking into account the load sharing characteristics.

• 한국컴퓨터산업학회논문지
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• 제9권4호
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• pp.157-170
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• 2008

본 연구에서는 메사츄세츄공과대학 마이크로전자 연구소에서 개발된 프로세서 PARWAN(PAR-1)으로 불리우는 줄여진 프로세서(a reduced processor)를 VHDL을 이용하여 Behavioral Leve에서 기술하고 Dataflow Level에서 상호 연결하여 기술하였고, VHDL로 설계된 CPU의 동작을 확인하고 시뮬레이션하기 위하여 Test-bench 방식을 이용하였다. <중략> 제시된 방식은 설계의 정보교환이 용이하고 동작의 표현이 정확하고 간결하였으며, 설계의 문서화가 용이하며, 구성된 프로세서의 동작을 확인하기가 용이하였다. VHDL의 Behavioral 기술은 설계자에게 설계된 시스템을 확인할 때 많은 도움을 주었으며 Dataflow 기술은 설계의 버스연결과 레지스터 구조를 확인할 때 유용하게 사용할 수 있었다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.745-750
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• 2009

In Korea, since the implementation of the GMO Law, the intrest of biosafety level 3(BL3) lab. is increasing. In this study, using CONTAM which is applying multizone modelling, the multizone simulation for design verification of BL3 lab. was performed. In BL3 lab., because required air change rate is greater than general estimated air-conditioning load and it is difficult to maintain room pressure difference efficiently, to maintain pressure difference between laboratory rooms is important through sealing condition of doors and proper airflow control of laboratory rooms. In this study, about BL3 lab.(M. tuberculosis research lab.), the multizone simulation for four kind of biohazard scenarios was performed in the case of unexpected spread of contaminants in the laboratory room, anteroom, corridor and inside of BSC. Multizone simulation results show that these approach methods are used as a tool for the design and verification of BL3 lab.