• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.420-426
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• 1994

A new method is proposed for the oxide lattice energy calculation. It is consisted of (1) setting a central and a computation domains in a real lattice, (2) calculation of inter-ionic potential producted by the associated portion of each ion to the relative domain, and (3) summing up the potential energies. Even with a slight expansion of the domain, the lattice energy converges to the published data. The method is superior than any other reported due to the simple and clear concept and the reduced computing.

• Communications of the Korean Mathematical Society
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• v.18 no.4
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• pp.755-765
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• 2003

Krylov-Bogoliubov-Mitropolskii method has been extended to obtain asymptotic solution of n-th order nonlinear differential system characterized by certain non-oscillatory processes. The damping force is considered in such a manner that one of the characteristic roots of the linear system becomes small and others are in integral multiple. The method is illustrated by an example. The solutions for different initial conditions show a good agreement with those obtained by numerical method.

• International Journal of Concrete Structures and Materials
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• v.18 no.1E
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• pp.63-70
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• 2006

This study tested the alkali-silica reactivity of various types of crushed stones, following the specifications of ASTM C 227 and C 1260, and the results obtained from the tests were compared. This study also analyzed the effects of particle size and grading of reactive aggregate based on the expansion of mortar-bar due to an alkali-silica. The effect of mineral admixtures to reduce the detrimental expansion caused by the alkali-silica reaction was investigated based on the method specified by ASTM C 1260. The mineral admixtures used in this study were fly ash, silica fume, metakaolin and ground granulated blast furnace slag. The replacement ratios of 0, 5, 10, 15, 25 and 35% were uniformly applied to all the mineral admixtures, and the replacement ratios of 45 and 55% were additionally applied for the admixtures that could sustain the workability at these ratios. The results indicate that replacement ratios of 25% for fly ash, 10% for silica fume, 25% for metakaolin and 35% for ground granulated blast furnace slag were the most effective in reducing the expansion due to the alkali-silica reaction under the experimental conditions of this study.

• Journal of Korean Academy of Nursing
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• v.32 no.6
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• pp.855-866
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• 2002

The purpose of study is to develop a home nursing care project model suitable for Korea's heath care system and policy directions for expansion and establishment of home nursing care. Method: The first, status of home nursing care program in medical institution and public health center was evaluated respectively in view of structure, process and performance. And then, issues of the program were analyzed in view of accessibility, safety, and sufficient supply. The second, demand projection of home nursing care according to income level and technical level of service that is needed to the subject was tried. In addition, the level of supply for home nursing care at present was estimated. The third, home nursing care program in advanced countries (Japan and U.S.A.) was examined. Result and Conclusion: Community-based home nursing care program is developed into public-operation model and private-operation model from above the sub-subject result. Functional network for referral system among related institutions is built up to meet various needs, regardless of accessibility to distance and economy. And prior settlements and policy directions for expansion and establishment of home nursing care are suggested.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.1
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• pp.1-8
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• 2007

When confronted with a query, question answering systems endeavor to extract the most exact answers possible by determining the answer type that fits with the key terms used in the query. However, the efficacy of such systems is limited by the fact that the terms used in a query may be in a syntactic form different to that of the same words in a document. In this paper, we present an efficient semantic query expansion methodology based on query patterns in a question category concept list comprised of terms that are semantically close to terms used in a query. The proposed system first constructs a concept list for each question type and then builds the concept list for each question category using a learning algorithm. The results of the present experiments suggest the promise of the proposed method.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.6
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• pp.911-923
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• 1995

The zone of expansion and contraction of arm surfaces was analyzed, the correlation between arm surface changes was studied, and ergonomic sleeve designs were presented in which the consideration of body surface changes is emphasized. Experiments were carried out which include 43 upper extremity segments, 21 motions and 35 female subjects. The major conclusions of the study are as follows : 1. As a sleeve drafting method, detailed measures should be applied on the base of the sensitivity of body surface changes. The range of arm surface changes can be divided into three zones : concentrated expansion zone, zone of little change, and contraction part. The maximum expansion zone was the upper part of elbow. 2. The correlations were higher in lengths than in circumferences. Arm lengths were mainly correlated with upper arms. The more detailed the arm surface was, the lower the correlations between surface changes were. So there was not a lot of relation between segment changes. Tendency of body surface changes depended on the anatomical structure of the upper extremity and the movements of arm muscles. 3. As an application of measures and ease, ergonomic sleeve designs weve presented in which arm surface changes were considered. Ergonomic sleeve designs are recommended for working clothes and sports wear.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1354-1359
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• 2007

This paper discusses the acoustic performance of simple expansion chamber using computational fluid dynamics(CFD). The CFD model consists of an axisymmetric grid with a single period sinusoid of acceptable amplitude and duration imposed at the inlet boundary condition. The time history of the static pressure is recorded at two points, one in the inlet pipe and one point in outlet pipe. The time history of the static pressure is converted to the frequency domain using Fourier Transform and the transmission loss (TL) of the muffler is obtained from the ratio of the static pressure at the inlet and outlet pipe. The transmission loss of CFD result is compared with that of the computational acoustic analysis using the boundary element method (BEM). There are some differences in two results due to the pressure drop according to the inlet and outlet pipe length. Therefore, the effects of the pressure drop to the transmission loss have to be considered.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.1-13
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• 2006

Vacuum laboratory in Korea Research Institute of Standards and Science (KRISS) was opened in 1983 for establishing and disseminating vacuum standard in Korea. The major three systems such as the ultrasonic interferometer manometer (UIM), the static expansion system (SES) and the dynamic expansion system (DES) with orifice and porous plug conductance are developed. In this study, the standard systems from low to ultra-high vacuum, uncertainty analysis by ISO regulation, and key and bilateral comparison results will be described.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.468-474
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• 2011

The flow field around baffle located sudden expansion and contraction channel was measured by PIV method and the effect according to height change of baffle built in the flow field was evaluated. The inlet flow velocity and the baffle height influence mutually to the size and flow pattern of the recycle flow of the back of the baffle and the size of the area of the water power jump passing the upper part of the baffle. In case of Reynolds number $Re=4{\times}10^3$, the critical value of baffle height is estimated around h/H=1.6 and there was a decreasing tendency as the inlet flow velocity was increased.

• Design & Manufacturing
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• v.8 no.2
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• pp.30-36
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• 2014

In this study, surface deformation patterns have been investigated by the rigid-plastic finite element method for friction factor test in solid cylinder compression process. AA1100 and AA6063 aluminum alloys, which show different work hardening characteristics respectively, have been adopted as model materials used for analysis. The main objective of this study is to provide the deformation mechanics in detail in solid cylinder compression process, especially at the die/workpiece interface that is closely related with the frictional conditions. For this reason, solid cylinder compression process has been numerically analyzed. The surface flow patterns at the contact boundary have been analyzed in terms of surface expansion, surface expansion velocity, pressure distributions exerted on the die surface along the die surface. By defining bulge factor, barreling phenomenon also have been examined with calibration curves to verify their effects on the surface flow pattern that is important for evaluating the frictional condition at the interface.