• Journal of the Korean Chemical Society
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• v.38 no.7
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• pp.473-479
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• 1994

Tungsten thin film was deposited on p-(100) silicon substrate by using the LPCVD(low pressure chemical vapor deposition) technique. $WF_6$ was used as a source gas for tungsten and $SiH_4$ was used as a reducing gas for $WF_6$. Tungsten thin film was deposited by either SiH4 or Si substrate reduction of $WF_6$ under cold-wall condition and it was deposited by $SiH_4$ reduction of $WF_6$ under hot-wall condition. The crystal structure of deposited thin film under both conditions were identified to be bcc (body centered cubic). The physical and electrical properties of deposited thin films were investigated. The deposited film under hot-wall condition changed to $WSi_2$ film by the annealing under $800^{\circ}C.$ From the experimental results and theoretical considerations, the change of the crystal structure of the thin film by annealing was discussed. $WSi_2$ thin film, which was known to have good compatibility with Si substrate, could be produced under hot-wall condition although the film properties were superior under cold-wall condition.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.3
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• pp.1-8
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• 2009

This thesis has analyzed the effect of the surge happening in flight on the engine performance, especially on the PW4000 turbofan engine. It is to be judged that the flight surge can occur more often at the time of takeoff than it does en route due to the fact that the engine parameters are prone to fluctuate. EPR is judged to be the most highly sensitive parameter responding when surge occurs. Both Engine rpm and Wf decrease almost simultaneously just like an EPR. During the take-off rolling, N1 vibration is more sensitive than the N2 vibration. Consequently, the surge can be detected by EGT increase, while the other parameters (EPR, rpm, Wf, etc) decrease.

• Journal of the Korean Wood Science and Technology
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• v.37 no.5
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• pp.426-433
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• 2009

This study investigates the tensile and morphological properties of nanocomposites prepared from poly(lactic acid) (PLA), wood flour (WF) and montmorillonite (MMT) by melt compounding with a twin screw extruder. In order to enhance the mechanical properties of PLA/WF composites, maleic anhydride grafted PLA (MAPLA) is synthesized as a compatibilizer. MAPLA prepared in the laboratory is characterized using FT-IR (Fourier transformed infrared spectroscopy). From the results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis for nanocomposites, we confirmed that silicate layers of MMT are intercalated and partially exfoliated. When 2 wt% MAPLA is added, the tensile strength and modulus of PLA/WF/MAPLA composites were higher than those of the PLA/WF composite. The addition of MMT increases the tensile modulus of PLA/WF/MAPLA composites but decreases the tensile strength.

• Journal of the Korean Wood Science and Technology
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• v.37 no.5
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• pp.434-439
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• 2009

This study investigates the thermal properties of nanocomposites prepared from poly(lactic acid) (PLA), wood flour (WF) and montmorillonite (MMT) by melt compounding with a twin screw extruder. In order to enhance the mechanical properties of PLA/WF composites, maleic anhydride grafted PLA (MAPLA) is synthesized as a compatibilizer. MAPLA prepared in the laboratory is characterized using FR-IR. From SEM microphotographs, the presence of MAPLA has a positive effect on the mechanical properties of WF-reinforced PLA composites. The addition of WF/MAPLA into neat PLA increased the glass transition temperature ($T_g$). The addition of 1 to 5 wt% MMT into PLA/WF/MAPLA composite decreases the $T_g$. The cold crystallization temperature ($T_{cc}$) was decreased by the addition of MMT. The MMT could act as effective nucleating sites of PLA crystallization. The thermal stability evaluated by thermogravimetric analysis (TGA) is improved with the contents of MMT up to 3 wt%.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.869-877
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• 2016

Necessity has compelled man to improve upon the art of tapping wind energy for power generation; an apt reliever of strain exerted on the non-renewable fossil fuel. The power generation in a Wind Farm (WF) depends on site and wind velocity which varies with time and season which in turn determine wind power modeling. It implies, the development of an accurate wind speed model to predict wind power fluctuations at a particular site is significant. In this paper, Box-Jenkins ARIMA (Auto Regressive Integrated Moving Average) time series model for wind speed is developed for a 99MW wind farm in the southern region of India. Because of the uncertainty in wind power developed, the economic viability and reliability of power generation is significant. Life Cycle Costing (LCC) method is used to determine the economic viability of WF generated power. Reliability models of WF are developed with the help of load curve of the utility grid and Capacity Outage Probability Table (COPT). ARIMA wind speed model is used for developing COPT. The values of annual reliability indices and variations of risk index of the WF with system peak load are calculated. Such reliability models of large WF can be used in generation system planning.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.3
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• pp.234-238
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• 1998

Two experiments were conducted with broiler chickens to determine cage floor preferences, the strength of preference for a particular floor type and to evaluate the effect of rearing broilers on the preferred cage floor on productivity. In experiment 1, chicks when offered free access to either wire (WF) or plastic (PF) mesh flooring, preferred the former. However, when the perferred floor type (WF) was illuminated at 800 lux, birds spent longer time on PF. Also provision of incandescent lamps at PF resulted in broilers spending significantly longer period on WF. In experiment 2, while floor type had no effect on growth of female chicks throughout the duration of study, male chicks grown on PF were heavier than their WF counterparts on Days 21, 28, 35 and 42. Neither livability, nor incidence of breast blisters and leg deformities was affected by floor type.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.218-221
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• 2007

고객과 공급업체 그리고 비즈니스 파트너들 간의 협업과 정보 공유를 수행하는 일련의 비즈니스 프로세스(Business Process)는 전자상거래에서 흔히 찾아 볼 수 있으며, 이는 Wf-XML을 기반으로 하고 있다. Wf-XML(workflow-XML)은 비동기 웹서비스 프로토콜로 워크플로 엔진의 상호연동을 위해 제안된 XML기반 프로토콜을 정의한 언어이다. 본 논문에서는 서로 다른 워크플로 엔진의 상호연동을 위하여 Wf-XML에서 제공하는 리소스 모델을 UML 다이어그램으로 모델링하여 기업들간의 상호연동과 협업을 위한 업무 흐름 파악을 용이하게 하는 모델을 제안한다.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.116-120
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• 1989

The optimal control problem of linear Lumped Parameter Systems (LPS) and Distributed Parameter Systems (DPS) is studied by employing the technique of Walsh functions (WF). By the using the elegant operational properties of WF, a direct computational algorithm for evaluating the optimal control and trajectory of LPS and DPS is developed. Without the need of solving the traditional matrix Riccati equation, the WF approach in shown very simple in form and convenient for use of a computer. The approximation is in the sense of least squares employing WF as the basis and the results are in the piecewise constant and discrete form.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.88-97
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• 2017

With the increasing of the penetration rate of large-scale wind farms, a reliable, highly available and cost-effective communication network is needed. As the failure of a WF communication network will significantly impact the control and real-time monitoring of wind turbines, network reliability should be considered into the WF design process. This paper analyzes the network reliability of different WF configurations for the Southwest Offshore project that is located in Korea. The WF consists of 20 WTs with a total capacity of 60 MW. In this paper, the performance is compared according to a variety of indices such as network unavailability, mean downtime and network cost. To increase the network reliability, partial protection and full protection were investigated as strategies that can overcome the impact of a single point of failure. Furthermore, the reliability performances of different network architectures are analyzed, evaluated and compared.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.112-114
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• 2005

현재의 급변하고 있는 비즈니스 환경은 기업 내부의 인트라적인 업무 처리 뿐만 아니라, 기업과 기업간의 상호교환을 통한 업무 수행을 요구하고 있으며, 이러한 요구 사항에 적절하게 대응할 수 있는 전략 개념이 프로세스 상호운용성이다. 본 논문에서는 현재의 비즈니스 시장에서 이슈화되고 있는 프로세스 상호운용성을 실제적으로 구현하고자 하는 과정의 일환으로 워크플로우 표준 단체인 WfMC(Workflow Management Coalition)에서 제안하는 상호운용성 표준 메시지 프로토콜인 Wf-XML 2.0을 지원하는 프로세스 엔진의 시스템 아키텍쳐를 구성하고자 하며, 기반이 되는 프로세스 엔진은 자체 연구 제작된 e-chautauqua라는 워크플로우 시스템을 이용하여 프로세스 상호운용성이 가능할 수 있도록 확장 설계하고자 한다.