• Journal of Korean Institute of Industrial Engineers
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• v.19 no.4
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• pp.105-114
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• 1993

In this article, a planar geodesic (2-dimensional minimum length curve between two points) on which the maximum curvature is constrained and with prescribed initial and terminal directions is studied. A generic problem is formulated by the minimum-time optimal control problem in free terminal time. It is shown that the optimal path ($G^2$) may contain a singular arc or not and that the general types of $G^2$ can he classified into the 3 classes of control sequences. Finally, the explicit form of $G^2$ is derived geometrically as well as algebraically form the main theorem of this article.

• Quality Improvement in Health Care
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• v.1 no.2
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• pp.34-43
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• 1994

Background: The average hospital stay in most Korean teaching hospitals is longer than that of hospitals in developed countries. The investigation of average hospital stay of teaching hospitals is considered as an important measure to evaluate the effectiveness of hospital management. In this article authors analyzed the relationship of several variables (hospital ownership, number of beds, location of hospitals, number of physician) to length of hospital stay in each clinical department. Methods: The average hospital stay of each clinical department of 184 teaching hospitals was investigated. Authors reviewed the papers of teaching hospitals, that was reported to the Korean Association of Hospitals. Results: The means of hospital stay day of hospitals were not significantly different according to the number of hospital beds and location of hospitals. Only the difference of hospital stay according to ownerships was significant. The length of stay was the highest in public hospitals and the lowest in juridical hospitals. Conclusions: The number of beds and location of hospitals were not associated with the average hospital stay. But ownerships affected the average hospital stay. The national or public hospitals had the longest length of hospital stay. Number of specialists and number of all physicians were closely related to the average hospital stay.

• Structural Engineering and Mechanics
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• v.85 no.6
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• pp.825-835
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• 2023

The effective buckling length factor is an important parameter in the elastic buckling analysis of steel structures. The present article aims at developing a new method that allows the determination of the buckling factor values for frames. The novelty of the method is that it considers the interaction between the bracing and the elastic supports for asymmetrical frames in particular. The approach consists in isolating a critical column within the frame and evaluating the rotational and translational stiffness of its restraints to obtain the critical buckling load. This can be achieved by introducing, through a dimensionless parameter 𝜙_i, the effects of coupling between the axial loading and bending stiffness of the columns, on the classical stability functions. Subsequently, comparative, and parametric studies conducted on several frames are presented for assessing the influence of geometry, loading, bracing, and support conditions of the frame columns on the value of the effective buckling length factor K. The results show that the formulas recommended by different approaches can give rather inaccurate values of K, especially in the case of asymmetric frames. The expressions used refer solely to local stiffness distributions, and not to the overall behavior of the structure.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.5
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• pp.416-428
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• 2001

In order to build a news archive system. the news video stream should be first segmented into several articles, ad their contents are abstracted effectively. This abstraction helps the users to understand the contents of the article without playing the whole video stream. This paper proposes a new article boundary detection scheme for the news video streams together with a new news article abstraction scheme using the shot types of the news video data. The shots in the news video are classified into anchor person shots, interview shots, speech shots, reporting shots, graphic shots, and others. Since the news article starts with an anchor shot whose duration is relatively longer than other shots with special screen structure, the article boundary in detected by the computing the length of the shot and checking the screen structure in the proposed scheme. For the effective abstraction of the article video, the graphic image located in the right-top of the anchor shot frames is primarily used in the proposed abstraction scheme since it is the abstraction of the article made by the producer of the news according to its contents so that it contains a lot of meaningful information. The key frames of the other shots except interview and report shots are also used to abstract the contents of the articles in the proposed scheme. Upon experimental results, the precision and recall values of the proposed article boundary detection scheme could be 92% and 96%, respectively. This paper also presents a design and implementation of a prototype news archive system on WWW that consists of an indexing tool, an authoring tool, a database for meta-data of the news, and a browsing tool.

• Structural Engineering and Mechanics
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• v.65 no.5
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• pp.573-585
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• 2018

This article presents strain gradient elasticity-based procedures for static bending, free vibration and buckling analyses of functionally graded rectangular micro-plates. The developed method allows consideration of smooth spatial variations of length scale parameters of strain gradient elasticity. Governing partial differential equations and boundary conditions are derived by following the variational approach and applying Hamilton's principle. Displacement field is expressed in a unified way to produce numerical results in accordance with Kirchhoff, Mindlin, and third order shear deformation theories. All material properties, including the length scale parameters, are assumed to be functions of the plate thickness coordinate in the derivations. Developed equations are solved numerically by means of differential quadrature method. Proposed procedures are verified through comparisons made to the results available in the literature for certain limiting cases. Further numerical results are provided to illustrate the effects of material and geometric parameters on bending, free vibrations, and buckling. The results generated by Kirchhoff and third order shear deformation theories are in very good agreement, whereas Mindlin plate theory slightly overestimates static deflection and underestimates natural frequency. A rise in the length scale parameter ratio, which identifies the degree of spatial variations, leads to a drop in dimensionless maximum deflection, and increases in dimensionless vibration frequency and buckling load. Size effect is shown to play a more significant role as the plate thickness becomes smaller compared to the length scale parameter. Numerical results indicate that consideration of length scale parameter variation is required for accurate modelling of graded rectangular micro-plates.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.42
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• pp.163-186
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• 2009

On April 11, 1980, the "United Nations on Contracts for the International Sale of Goods" ("CISG") was prepared by the United Nations Commission on International Trade Law (UNCITRAL) and approved by a diplomatic conference in Vienna providing uniform law for international sales of goods. It took effect as of March 1, 2005, in Korea. It is set forth on the seller's remedies for breach by the buyer Section III (Art. 61 - 65) under the CISG. In this study, the focus is only on the seller's notice fixing additional final period for performance (Art. 63) and the right to avoid the contract (Art. 64), with examination on some relevant foreign arbitral awards rendered by the ICC and the CIETAC together. Article 63 provides that the seller may fix an additional period of time for reasonable length for performance by the buyer of his obligation. It was found from the above arbitral awards that the concept of 'reasonable length' should be decided on a case-by-case basis, given the specific circumstances in the case [Art. 63(1)]. It is provided that unless the seller has received a notice that he will not perform within the period so fixed, the seller may not, during that period, resort to any remedy for breach of contract in accordance with Article 63(2). Article 64(1) provides the means and grounds for avoidance of the contract, which can be avoided 1) when the breach of the buyer amounts to a fundamental breach of contract, or 2) when the additional period of time is fixed by the seller, unless the buyer declares that he will not perform so within the period of fixed time. As we examined in the above arbitral awards, it was held that the contract is avoided when the seller sends the final notice stating that he will avoid the contract, after the expiration of the additional period of time fixed by the seller in the ICC award. On the contrary, it was held that the contract should be deemed to be avoided exactly when the expiration of additional period noted in the avoidance notice is elapsed in the CIETAC award. Article 64(2) sets time limits for avoidance.

• Korean Journal of Mathematics
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• v.24 no.3
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• pp.567-572
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• 2016

Quadratic residue codes are cyclic codes of prime length n defined over a finite field ${\mathbb{F}}_{p^e}$, where $p^e$ is a quadratic residue mod n. They comprise a very important family of codes. In this article we introduce the generalization of quadratic residue codes defined over Galois rings using the Galois theory.

• Journal of the Korean Data and Information Science Society
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• v.12 no.1
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• pp.127-133
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• 2001

In this article we establish multivariate cumulative sum (CUSUM) control charts based on residual vector with correlated observations. We first find the residual vector and its expectation and variance-covariance matrix and then evaluate the average run length (ARL) of the control charts.

• Fibers and Polymers
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• v.7 no.3
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• pp.310-316
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• 2006

In this article, an attempt has been made to explain the failure mechanism of spun yams. The mechanism includes the aspects of generation and distribution of forces on a fibre under the tensile loading of a yam, the free body diagram of forces, the conditions for gripping and slipping of a fibre, and the initiation, propagation, and ultimate yam rupture in its weakest link. A simple mathematical model for the tenacity of spun yams has been proposed. The model is based on the translation of fibre bundle tenacity into the yam tenacity.

• Journal of the Korea Safety Management & Science
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• v.1 no.1
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• pp.111-121
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• 1999

An important problem in process adjustment using feedback is how often to sample the process and when to apply an adjustment. Schemes are designed to minimize the overall cost. The cost is taken the frequency with which they require observations to be made, and the resulting overall length of time between adjustments. In this article, the process adjustment which is based on the adaptive EWMA forecasts is derived. An example is presented to improve the standard variation through the analysis of data series.