• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 C
• /
• pp.1349-1351
• /
• 2001

Polycrystalline diamond films are deposited by using a microwave plama CVC system, where the bias-enhanced nucleation (BEN) method is employed. Effects of the varying microwave power, the surface treatment by hydrogen plasma, and the cyclic hydrogen etching during deposition on the crystallinity as well as on the surface roughness of deposited films are examined by Raman spectroscopy, SEM, and AFM. A novel method for achieving a smoother diamond surface is also suggested through the indirect wafer bonding and back-side polishing.

• Transactions on Electrical and Electronic Materials
• /
• 제1권1호
• /
• pp.6-11
• /
• 2000

The hydrogen plasma treatment of silicon wafers in the reactive ion-etching mode was studied for the application to silicon-on-insulator wafers which were prepared using the wafer bonding technique. The chemical reactions of hydrogen plasma with surface were used for both surface activation and removal of surface contaminants. As a result of exposure of silicon wafers to the plasma, an active oxide layer was found on the surface. This layer was rendered hydrophilic. The surface roughness and morphology were examined as functions of the plasma exposing time and power. In addition, the surface became smoother with the shorter plasma exposing time and power. The value of initial surface energy estimated by the crack propagation method was 506 mJ/㎡, which was up to about three times higher as compared to the case of conventional direct using the wet RCA cleaning method.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 D
• /
• pp.1330-1332
• /
• 1998

Polycrystalline diamond films are deposited on a Si substrate by employing a 2.45 GHz $\mu$-wave plasma CVD system. Prior to depositing the diamond film, a DPR(diamond photo-resist) layer is coated to enhance the nucleation density. The growth rate of diamond films increases with the $\mu$-wave power and approaches to be about $1.5{\mu}m/hr$ at 1100 W. Structural properties of diamond films deposited are characterized from their SEM photographs, Raman spectra, and AFM surface images. Lager grain size, higher intensity of diamond peak, and smoother surface are observed for films deposited at a higher power. The possible mechanism on the diamond growth is also discussed to explain the experimental results.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.50.2-50
• /
• 2001

Optimal control problems are notoriously difficult to solve either analytically or numerically except for limited cases of having simple dynamics. Evolutionary programming is a promising method of solving various optimal control problem arising in practice since it does not require the expression of Lagrange´s adjoint system and that it can easily implement the inequality constraints on the control variable, In this paper, evolutionary programming is combined with spline method, so the smoother control profile and the Jumping times could be obtained. The optimal profiles obtained by the proposed method are compared with exact solution if it is available. With more complicated model equation, the proposed method showed better performance than other researchers´. It is demonstrated that the evolutionary programming with spline method can ...

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제5권6호
• /
• pp.1147-1165
• /
• 2011

We present a simple and cost effective rate control scheme for streaming video over a wireless channel by using the information of mobile devices' buffer level. To prevent buffer fullness and emptiness at receivers, the server should be able to adjust sending rate according to receivers' buffer status. We propose methods to adjust sending rate based on the buffer level and discrete derivative of the buffer occupancy. To be compatible with existing network protocols, we provide methods to adjust sending rate by changing the inter-packet delay (IPD) at the server side. At every round-trip time, adjustments of sending rate are made in order to achieve responsiveness to sudden changes of buffer availabilities. A series of simulations and the prototype system showed that the proposed methods did not cause buffer overflows and it can maintain smoother rate control and react to bandwidth changes promptly.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제2권4호
• /
• pp.184-193
• /
• 2008

We examine the performance of genetic algorithms using binary encoding, with respect to a change of basis. Changing the basis can result in a change in the linkage structure inherent in the fitness function. We test three simple functions with differing linkage strengths and analyze the results. Based on an empirical analysis, we show that a better basis results in a smoother fitness landscape, hence genetic algorithms based on the new encoding method provide better performance.

• 소성∙가공
• /
• 제15권8호
• /
• pp.539-543
• /
• 2006

Experimental studies are carried out in order to investigate the effects of heat treatment on the surface machined by W-EDM. In this work, two ways of heat treatment after W-EDM are considered. As a comparison, the machined surface by a traditional method such as milling/grinding is also considered. Thereby, specimens are prepared by four different machining methods. Those are (1) milling and then grinding, (2) wire-cut electric discharge machining (W-EDM), and (3) low temperature heat treatment or (4) high temperature heat treatment after W-EDM. The resulting surface roughness are measured and the changes of surface microstructures are investigated using the scanning electron microscope (SEM) with energy dispersive X-ray spectrometer (EDS). In general, heat treatment after W-EDM result in smoother surface and better chemical composition at the machined surface. Especially, high temperature tempering could remove defects in the thermally affected zone, which cause an overall deterioration of the surface machined by W-EDM.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.148-150
• /
• 2005

Indium tin oxide (ITO) thin film was polished by chemical mechanical polishing (CMP) immediately after pad conditioning with the various conditioning temperatures by control of de-ionized water (DIW). Light transparent efficiency of ITO thin film was improved after CMP process after pad conditioning at the high temperature because the surface morphology was smoother by soften polishing pad and decreased particle size.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
• /
• 제16권1호
• /
• pp.35-42
• /
• 2010

As a functionally complicated facility, it requires rational strategy to accommodate multi-functional needs to plan a hospital. Ambulatory surgery units located in large hospitals have problems such as longer waiting time and congestion for patients due to complicated planning and organization within limited area, which raise needs for independent ambulatory surgery centers to enable smoother medical treatment for patients. To design an independent ambulatory surgery center, understanding of zoning and layout of each unit needs is particularly required. This study focuses on research of efficient zoning/organization of day surgery unit and circulation arrangements of ambulatory surgery centers by analyzing various examples abroad, which will eventually help finding appropriate way of planning domestic ambulatory surgery centers. Specific area of research includes ambulatory surgery process, programmatic requirements, spatial organization of the facility, layout of surgery unit and circulation arrangements of ambulatory surgery centers.

• 대한전기학회논문지
• /
• 제34권10호
• /
• pp.407-417
• /
• 1985

This paper describes a new method for the design of adaptive model-following control systems. This design concept is developed using the theory of slide mode. Authors present new results on the sliding control methodology to achieve accurate tracking for a class of multi-input multi-output, time-varying systems in the presence of parameter variations and disturbances. This algorithm can be easily applied to the multivariable control systems and obtained a smoother control signal in comparison to variable structure model following control systems. The design technique is easy and the control structure is simple. The design requires little computational effort. The control system is less sensitive to plant parameter variations and noise disturbances.