• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.669-673
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• 2001

The objective of this paper is to predict and evaluate the sealing performance of the thermoplastic rubber component in the proto-design stage. The large strain and large deformation properties of rubber are modeled by strain energy function and the related material constants are calculated from the test data. The viscoelastic property of the rubber is also considered using the coefficients in a Prony series representation of a viscoelastic modulus ken the compression stress relaxation test. The results show that the current design of cap mount system has 2-different stiffness caused by the cap-mount contact and the viscoelastic property of rubber plays an important role in time dependent deformation.

• Journal of Communications and Networks
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• 제9권1호
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• pp.67-74
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• 2007

The performance of dual diversity receivers operating over correlated Ricean fading channels is analyzed. Using a previously derived rapidly converging infinite series representation for the bivariate Ricean probability density function, analytical expressions for the statistics of dual-branch selection combining, maximal-ratio combining, and equal-gain combining output signal-to-noise ratio (SNR) are derived. These expressions are employed to obtain novel analytical formulae for the average output SNR, amount of fading, average bit error probability, and outage probability. The proposed mathematical analysis is used to study various novel performance evaluation results with parameters of interest the fading severity, average input SNRs, and the correlation coefficient. The series convergence rate is also examined verifying the fast convergence of the analytical expressions. The accuracy of most of the theoretical performance evaluation results are validated by means of computer simulations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.469-469
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• 2000

The use of orthogonal functions with the aim of adapting the system and signal representation to the specific properties of the systems and signals has a long history. A least-squares identification method is studied that estimates a finite number of expansion coefficients in the series expansion of a transfer function, where the expansion is in terms of recently introduced generalized orthogonal functions. It is shown that there exist orthogonal functions that are generated by stable linear dynamical systems.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.866-871
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• 1994

B-spline curves and surfaces are effective solutions for design and modelling of the freeform models. The control methods of these are using with control points, knot vectors and weight of NURBS. Using control point is easy and resonable for representation of general models. But the movement of control points bring out the reformation of original convex hull. The B-splines with nonuniform knot vector provide good result of the shape modification without convex hull reforming. B-splines are constructed with control points and basis functions. Nonuniform knot vectors effect on the basis functions. And the blending curves describe the prorities of knot vectors. Applying of these, users will forecast of the reformed curves after modifying controllabler primitives.

• Communications for Statistical Applications and Methods
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• 제22권2호
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• pp.159-172
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• 2015

This paper considers the problem of reconstructing an underlying signal from noisy data. This paper presents a reconstruction method based on synchrosqueezed wavelet transform recently developed for multiscale representation. Synchrosqueezed wavelet transform based on continuous wavelet transform is efficient to estimate the instantaneous frequency of each component that consist of a signal and to reconstruct components. However, an objective selection method for the optimal number of intrinsic mode type functions is required. The proposed method is obtained by coupling the synchrosqueezed wavelet transform with cross-validation scheme. Simulation studies and musical instrument sounds are used to compare the empirical performance of the proposed method with existing methods.

• 소성∙가공
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• 제19권5호
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• pp.296-304
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• 2010

It is still needed to study the effect of process conditions on the final properties of injection-molded parts for producing precision optical products. Especially, the optical anisotropy, i.e., birefringence, is a significant factor to affect the function of many optical components. In the present study we have focused on the effect of holding and compression processes on the birefringence remaining in the transparent disc by examining the gap-wise distribution of birefringence and extinction angle. As a result, two extra birefringence and extinction peaks near the center in thickness direction showed the effect of holding pressure, which came from the flow in packing stage. However, more uniform birefringence distribution than injection-only cases could be found in injection/compression cases. Depends on the process condition even the flow reversal could be found from the distribution of extinction angle. Finally, graphical representation of optical indicatrix was added for better understanding the final structure of injection-only and injection/compression cases.

• 한국산업융합학회 논문집
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• 제19권2호
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• pp.75-80
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• 2016

This study proposes a efficient technology to control the optimal trajectory planning and real-time implementation method which can perform autonomous travelling for unmaned factory automation. Online path planning should plan and execute alternately in a short time, and hence it enables the robot avoid unknown dynamic obstacles which suddenly appear on robot's path. Based on Route planning and control algorithm, we suggested representation of edge cost, heuristic function, and priority queue management, to make a modified Route planning algorithm. Performance of the proposed algorithm is verified by simulation test.

• 디지털융복합연구
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• 제5권2호
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• pp.155-165
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• 2007

The meaning of images are changed rapidly by a time, and the images' social function and skills are different by times. Nowadays, the reasons to have different meanings of images are the different ways of representation and reproduction of images by new digital technologies. However, the images are communicating with each other, and the image makers should have responsibility to represent the images. Also, the images should be concerned in social, cultural context, and focused on positive ways to represent. It is hard to predict the future of images, but people shouldn't be controled by manipulated digital images. Therefore, image makers need to have right ethics and morals in digital era not to be controled by commercial enterprises.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1100-1102
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• 1997

This paper presents a generalized multi-parameter distribution method for the convolution of linear combination of random variables to calculate system load flow in a conventional probabilistic approach and also presents a conceptual possibilistic approach using fuzzy set theory to manage uncertainties. The probability distribution function is transformed into an appropriate possibilistic representation under the compromise between the transformation consistency and the human updating experience. The IEEE 25-bus system is used to demonstrate the capability of the proposed algorithm.

• Wind and Structures
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• 제1권3호
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• pp.203-223
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• 1998

This paper describes in detail the features of an extensive study on Spectral Density Functions (SDF's) of wind pressures acting on several low building roof geometries carried out in a boundary layer wind tunnel. Various spectral characteristics of wind pressures on roofs with emphasis on derivation of suitable analytical representation of spectra and determination of characteristic spectral shapes are shown. Standard spectral shapes associated with various zones of each roof and their parameters are provided. The established spectral parameters can be used to generate synthetic spectra adequate for the simulation of wind pressure fluctuations on building surfaces in a generic fashion.