• Journal of the Korean Society for Library and Information Science
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• v.19
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• pp.113-149
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• 1990

The RAK has in general adopted the provisions of the paris principles to a far greater extent than many other cataloguing codes. And the analyses confirm that the determination of the main entries in German cataloging rules is a rather complex process and one which can result in inconsistent, arbitrary decisions. And the selection of the main entry requires a considerable amount of decision making which is time-consuming and costly. From the point of view of computers, all entries are equal as points of retrieval. In light of the above considerations the most important recommendation to be made is that the main entry principle be abandoned from cataloging theory and practice and be replaced by the title entry. It would eliminate the need for personal judgments required by the present rule. In so doing, it would bring uniformity and Standardization to cataloging practice. Use of the title entry would reduce the time and effort spent on the selection of the main entry which serves no important purpose in the catalog. Therefore title entry is more developed finding device than author entry in direct approach for document retrieval.

• International Journal of Ocean System Engineering
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• v.3 no.1
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• pp.22-32
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• 2013

A heuristic physical theory of diffraction (PTD) for an acoustic impedance wedge is proposed. This method is based on Ufimtsev's three-dimensional PTD, which is derived for an acoustic soft or hard wedge. We modify the original PTD according to the process of physical optics (or the Kirchhoff approximation) to obtain a 3D heuristic diffraction model for an impedance wedge. In principle, our result is equivalent to Luebbers' model presented in electromagnetism. Moreover, our approach provides a useful insight into the theoretical basis of the existing heuristic diffraction methods. The derived heuristic PTD is applied to an arbitrary impedance polygon, and a simple PTD formula is derived as a supplement to the physical optics formula.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.4
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• pp.20-27
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• 1995

A numerical simulation is carried out on the directivity synthesis of ultrasonic transducers by point source array. Gauss elimination method is practiced by means of a directive method to realize the desired directivity. Desired directivity is chosen to be that of a directivity of line source, a beam width and a direction arbitrary specified. On the numerical result, Gauss elimination method is showed high speed ca- lculative simulation and stability of system more than iterative method(LMS, DFP). Numerical simulations are carried out by PC(CPU:80486 DX2, RAM 16Mbyte).

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.2
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• pp.1-8
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• 2003

Conventionally used linear or circular interpolator is undesirable for the precision machining of 3D free-form surface as the following reason: the transmission errors due to the huge number of data, discontinuity of segmentation, unsmooth motion speed. To this regard, modern CNC machine tools are designed with the function of machining arbitrary parametric curves. However, these systems don't consider the adaptive federate, which dominates the quality of the machining process. This paper proposes a NURBS interpolator for the constant material removal rate. That is accomplished by the variable federate using curvature of curve. The curvature-compensated feederate system has important Potential applications in ensuring part accuracy and protecting cutting tool. The simulated result show it can be applicable to the real machining.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.488-492
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• 1993

This paper proposes a new approach to the optimization method of a blending process with neural network. The method is based on the error backpropagation learning algorithm for neural network. Since the neural network can model an arbitrary nonlinear mapping, it is used as a system solver. A fuzzy membership function is used in parallel with the neural network to minimize the difference between measurement value and input value of neural network. As a result, we can guarantee the reliability and stability of blending process by the help of neural network and fuzzy membership function.

• The Korean Journal of Applied Statistics
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• v.22 no.1
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• pp.205-220
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• 2009

For modeling skewed semicircular data, we derive new family of the exponential distributions. We extend it to the l-axial exponential distribution by a transformation for modeling any arc of arbitrary length. It is straightforward to generate samples from the f-axial exponential distribution. Asymptotic result reveals two things. The first is that linear exponential distribution can be used to approximate the l-axial exponential distribution. The second is that the l-axial exponential distribution has the asymptotic memoryless property though it doesn't have strict memoryless property. Some trigonometric moments are also derived in closed forms. Maximum likelihood estimation is adopted to estimate model parameters. Some hypotheses tests and confidence intervals are also developed. The Kolmogorov-Smirnov test is adopted for goodness of fit test of the l-axial exponential distribution. We finally obtain a bivariate version of two kinds of the l-axial exponential distributions.

• The Korean Journal of Applied Statistics
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• v.23 no.6
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• pp.1125-1145
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• 2010

For modeling(skewed) semicircular data, we derive a new exponential family of distributions. We extend it to the l-axial exponential family of distributions by a projection for modeling any arc of arbitrary length. It is straightforward to generate samples from the l-axial exponential family of distributions. Asymptotic result reveals that the linear exponential family of distributions can be used to approximate the l-axial exponential family of distributions. Some trigonometric moments are also derived in closed forms. The maximum likelihood estimation is adopted to estimate model parameters. Some hypotheses tests and confidence intervals are also developed. The Kolmogorov-Smirnov test is adopted for a goodness of t test of the l-axial exponential family of distributions. Samples of orientations are used to demonstrate the proposed model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2292-2297
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• 2010

To improve the performances of Sawyer motors and to regulate yaw rotation, various feedback control methods have been developed. Almost all of these methods require information on the position, velocity or full state of the motor. Therefore, in this paper, a nonlinear observer is designed to estimate the full state of the four forcers in a Sawyer motor. The proposed method estimates the full state using only positional feedback. Generally, Sawyer motors are operated within a yaw magnitude of several degrees; outside of this range, Sawyer motors step out. Therefore, this observer design assumes that the yaw is within ${\pm}90^\b{o}$. The convergence of the estimation error is proven using the Lyapunov method. The proposed observer guarantees that the estimation error globally exponentially converges to zero for all arbitrary initial conditions. Furthermore, since the proposed observer does not require any transformation, it may result in a reduction in the commutation delay. The simulation results show the performance of the proposed observer.

• Bulletin of the Korean Mathematical Society
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• v.50 no.2
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• pp.611-626
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• 2013

In the paper we study the finite-time ruin probability in a general risk model with constant interest force, in which the claim sizes are pairwise quasi-asymptotically independent and arrive according to an arbitrary counting process, and the premium process is a general stochastic process. For the case that the claim-size distribution belongs to the consistent variation class, we obtain an asymptotic formula for the finite-time ruin probability, which holds uniformly for all time horizons varying in a relevant infinite interval. The obtained result also includes an asymptotic formula for the infinite-time ruin probability.

• Journal of the Korean Institute of Navigation
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• v.21 no.2
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• pp.59-67
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• 1997

This paper describe the method and the result of making a fiber optic gyrocompass measuring the heading angles of a ship with a fiber optic sensor. As the method seeking for the heading angles, it is possible to get the heading angles by measuring the output signals from a stationary fiber optic sensor in at least three directions such as a heading direction and other two directions having phase difference ${\phi}1$ and ${\phi}2$ to the heading. We made the static fiber optic gyrocompass by a high performance fiber optic sensor having scale factor of 210mV/deg/s and resolution of 0.5deg/hr using this principle. The accuracy of this system was $0.29^{\circ}$ from 20 numbers of data measuring the arbitrary heading angle.