• 한국분무공학회지
• /
• 제5권2호
• /
• pp.53-60
• /
• 2000

An aerodynamically progressed model, which is called APTAB model. has been proposed for more accurate prediction of the deformation and breakup of a spray. Especially, the effects of the droplet deformation on the droplet aerodynamic external force are considered in this model, which was neglected in TAB model. It is found that the predicted droplet deformation using APTAB model shows better agreement with experimental data than those of other models for the droplets in both bag-type and shear-type breakup regimes. A new breakup criterion has been proposed to predict more reasonable breakup quantities, such as breakup deformation length, time and so on; i.e., it is defined that the breakup occurs when the internal liquid phase pressure of the deformed droplet at the equator is greater than that of the pole. The proposed breakup criterion shows more physical relationship between the degree of droplet deformation at breakup and the corresponding breakup Weber number as compared with the results with TAB and DDB models. Therefore, it provides better predictions of the experimental data than TAB and DDB models for the droplet deformation and time in both bag-type and shear-type breakup regimes.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제12권4호
• /
• pp.473-481
• /
• 2012

For a mesa-isolated small geometry SOI MOSFET, the potentials in the silicon film, front, back, and side-wall oxide layers can be derived three-dimensionally. Using Taylor's series expansions of the trigonometric functions, the derived potentials are written in terms of the natural length that can be determined by using the derived formula. From the derived 3-D potentials, the minimum values of the front and the back surface potentials are derived and used to obtain the closed-form expressions for the front and back gate threshold voltages as functions of various device parameters and applied bias voltages. Obtained results can be found to explain the drain-induced threshold voltage roll-off and the narrow width effect of a fully depleted small geometry SOI MOSFET in a unified manner.

• International Journal of Aeronautical and Space Sciences
• /
• 제13권2호
• /
• pp.199-209
• /
• 2012

An advanced aeroelastic formulation for flutter analyses is presented in this paper. Refined 1D structural models were coupled with the doublet lattice method, and the g-method was used for flutter analyses. Structural models were developed in the framework of the Carrera Unified Formulation (CUF). Higher-order 1D structural models were obtained by using Taylor-like expansions of the cross-section displacement field of the structure. The order (N) of the expansion was considered as a free parameter since it can be arbitrarily chosen as an input of the analysis. Convergence studies on the order of the structural model can be straightforwardly conducted in order to establish the proper 1D structural model for a given problem. Flutter analyses were conducted on several wing configurations and the results were compared to those from literature. Results show the enhanced capabilities of CUF 1D in dealing with the flutter analysis of typical wing structures with high accuracy and low computational costs.

• 한국정밀공학회지
• /
• 제21권1호
• /
• pp.173-180
• /
• 2004

This paper presents the effect of varying boundary conditions such as ground subsidence, internal pressure and temperature variation for buried pipelines on failure prediction by using a failure probability model. The first order Taylor series expansion of the limit state function incorporating with von-Mises failure criteria is used in order to estimate the probability of failure mainly associated with three cases of ground subsidence. Using stresses on the buried pipelines, we estimate the probability of pipelines with von-Mises failure criterion. The effects of varying random variables such as pipe diameter, internal pressure, temperature, settlement width, load for unit length of pipelines, material yield stress and pipe thickness on the failure probability of the buried pipelines are systematically studied by using a failure probability model for the pipeline crossing ground subsidence regions which have different soil properties.

• Smart Structures and Systems
• /
• 제6권2호
• /
• pp.101-113
• /
• 2010

This paper presents the results of a series of experiments conducted to model a magnetorheological damper operated in shear mode. The prototype MR damper consists of two parallel steel plates; a paddle covered with an MR fluid coated foam is placed between the plates. The force is generated when the paddle is in motion and the MR fluid is reached by the magnetic field of the coil in one end of the device. Two approaches were considered in this experiment: a parametric approach based on the Bingham, Bouc-Wen and Hyperbolic Tangent models and a non parametric approach based on a Neural Network model. The accuracy to reproduce the MR damper behavior is compared as well as some aspects related to performance are discussed.

• 정보관리학회지
• /
• 제7권1호
• /
• pp.59-67
• /
• 1990

본 연구는 참고 업무 분야에 전문가 대체 시스템(expert system)이라는 전산학의 시 스템 개발 기술을 도입하여 질문이 발생하게 된 경위와 질문의 규명, 그리고 적절한 해답을 제공하는데 필요한 지식을 사전에 지식 베이스로 구축함으로써 이용자 및 참고 사서가 해답 을 얻는데 유용하게 이용될 수 있도록 한다는데 그 목적이 있다.

• 한국도서관정보학회지
• /
• 제22권
• /
• pp.245-276
• /
• 1995

This study analyzed the process of information service and its factors in the cognitive viewpoint. And developed a conceptual model to help in developing future information systems and services. The results of this study were summarized as follows : 1) The paradigm of information user study is changing from the system-centered to the user-centered one. 2) The researchers describe the user's internal cognitive process as the starting point of the information service. 3) The user's personal cognitive process influence the process of the information service over. And the focus is a microscopic one including the factors of the perception and recognition of the stimulus, remembering and searching information, reasoning the rules, recognition of the patterns, formalization of the concepts, etc. 4) The information librarian performs the role as a knowledge/ information system interface, and his knowledge structure reflects the organization of that knowledge/information system. 5) The information librarians can perform their role as information specialists actively and offensively. And the performance of the librarians can be measured on the scales of the su n.0, pplying capability of relevant information and the client satisfaction.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제50권3호
• /
• pp.115-119
• /
• 2001

This paper presents an efficient and simple method for analyzine maximum simultaneous switching noise (SSN) on ground interconnection networks in CMOS systems. For the derivation of maximum SSN expression, we use ${\alpha}$-power law MOS model and Taylor's series approximation. The accuracy of the proposed method is verified by comparing the results with those of previous researches and HSPICE simulations under the contemporary process parameters and environmental conditions. The proposed method predicts the maximum SSN values more accurately when compared to existing approaches even in most practical cases such that exist some output drivers not in transition.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1998년도 춘계 총회 및 학술발표회
• /
• pp.105-109
• /
• 1998

1. Introduction : In microfiltration the transport, deposition and removal of particles control cake formation on a filter. In this connection a new model on cake formation, based on the wall shear stress, was tested here in comparison with experiments of fine particle slurry under Taylor-vortex flow. The model expresses the deposition process for particles as two first-order steps in series of mass transfer and adhesion, and their removal process as a linear relation to the wall shear stress. This embraces characteristics of both dead-end and crossflow filtration. The correlation resulting from fitting to experimental data represented the experimental data reasonably well. This study will be helpful in analyzing fouling in heat exchangers.

• 말소리와 음성과학
• /
• 제6권2호
• /
• pp.29-34
• /
• 2014

In the Vector Taylor Series (VTS)-based noisy speech recognition methods, Hidden Markov Models (HMM) are usually trained with clean speech. However, better performance is expected by training the HMM with noisy speech. In a previous study, we could find that Minimum Mean Square Error (MMSE) estimation of the training noisy speech in the log-spectrum domain produce improved recognition results, but since the proposed algorithm was done in the log-spectrum domain, it could not be used for the HMM adaptation. In this paper, we modify the previous algorithm to derive a novel mathematical relation between test and training noisy speech in the cepstrum domain and the mean and covariance of the Multi-condition TRaining (MTR) trained noisy speech HMM are adapted. In the noisy speech recognition experiments on the Aurora 2 database, the proposed method produced 10.6% of relative improvement in Word Error Rates (WERs) over the MTR method while the previous MMSE estimation of the training noisy speech produced 4.3% of relative improvement, which shows the superiority of the proposed method.