• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.66-69
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• 2006

In the present study, we propose a virtual boundary method for simulation of massive inextensible flexible strings immersed in viscous fluid flow. The fluid motion is governed by the Navier-Stokes equations and a momentum forcing is added in order to bring the fluid to move at the same velocity with the immersed surface. A massive inextensible flexible string model is described by another set of equations with an additional momentum forcing which is a result of the fluid viscosity and the pressure difference across the string. The momentum forcing is calculated by a feedback loop. Simulations of several numerical examples are carried out, inlcuding a hanging string which starts moving under gravity without ambient fluid, a string swimming within a uniform flow and a uniform flow over two side-by side strings. The numerical results agree well with the theoretical analysis and previous experimental observations. Preliminary results of a swimming elongated fishlike body will also be presented.

• Journal of the Korean Society of Costume
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• v.64 no.6
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• pp.91-101
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• 2014

String, as clothing material, has played a functional, symbolic and decorative role in garment traditionally. The string has a shape of continuous line, which is one of the basic elements for the design: points, lines and sides. It can effectively represent the silhouette by making our vision flow to a certain direction. This study reinterprets the traditional form of string in a new modern way by developing "Tube-Shaped String" which has an empty hole in the middle. As a creative attempt, the new tube-shaped string can be used for fashion design by applying it to unique shapes, colors, textures, and draping expressions. In a role dimension, this string can become the main fabric material. The methods of the study are as follows. First, it examines the traditional shape and role of string in the history of garment. Second, it studies modern designers, such as Christian Dior, Ann Demeulemeester, Dolce & Gabbana, and 3.1 Phillip Lim, who have applied the string to their design, and have explored the various potentials of the string in the past four years. Finally, based on the theoretical research and practical analysis, this study creates a new tube-shaped string, applying its own technique to fabricating three garments: jacket, dress, and body suit. As a result, each garment shows unique silhouettes, rich texture and color, and rhythmical movement. The unique silhouettes reflect the shape and movement of different bodies. The texture and color are created through the shades of the string which come from the overlapping strips. The garments come with an unbeatable aesthetic design compared to conventional uniform design. As a new material in clothing, this tube-shaped string can be developed to satisfy the public, which has widely varying tastes in fashion.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.2
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• pp.146-150
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• 2012

Free vibrations of strings due to initial conditions have been analyzed by the conventional mode summation method, and the nondimensionalized displacements and velocities have been derived in the form of infinite series. The results show wave propagating phenomena and confirmed by experiments using the high speed camera. Other physical characteristics have been discussed and examined with help of waveform solutions.

• Journal of the Korean Society of Costume
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• v.66 no.5
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• pp.66-81
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• 2016

This study is designed to understand the problems of existing Korean male soldiers' winter uniform tops by researching its current state, and contribute to developing uniforms with improved size and motion appropriateness. Military bases were visited to research satisfaction of size and motion appropriateness of the current winter uniform tops. 193 soldiers were surveyed and interviewed, and the shape and fit of the standard sizes of the inner and outer layers of the current winter uniform were analyzed. Findings of this study are as follows. 1) Compared to the new combat uniforms that soldiers were wearing in their appropriate size (of the 44 sizes), there were many cases where the soldiers were not wearing winter uniform inner (of the 8 sizes) or outer (of the 18 sizes) layers in the correct size for their body. 2) A total of 37 combat uniform sizes appropriate for the body shapes were expected to be newly applied, and inside and outside layers of winter tops would be presented as sets of 14 different sizes in step with the new combat uniform sizes, instead of the existing 8 inside layer sizes and 18 outside layer sizes. 3) The inner and outer layer of the existing winter uniform tops had several problems with the shape and fit. First, the inner layer was shorter than the combat uniform. Its shoulder width was wide, but the sleeve length was short creating lack of coverage, and the angle connecting the sleeve and bodice was very small creating a high sleeve cap curve and narrow sleeve width that make motions difficult and cause discomfort. As for the outer layer, the hem moved up when soldiers bent over or adjusted the waist string so the top could not sufficiently cover, the shoulder width was wide and the sleeve length was short, requiring improvements.

• Structural Engineering and Mechanics
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• v.49 no.4
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• pp.427-448
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• 2014

At present, the time of easy oil and gas is over. Now, the largest part of fossil fuels is concentrated in the deepest levels of tectonic structures and in the sea shelves. One of the most cumbersome operations of their extraction is the bore-hole drilling. In connection with austere tectonic and climate conditions, their drivage every so often is associated with great and diversified technological difficulties causing emergencies on frequent occasions. As a rule, they are linked with drill string accidents. A key role in prediction of these situations should play methods of theoretical modelling. For this reason, there is a growing need for development and implementation of new numerical methods for computer simulation of critical and post-critical behavior of drill strings (DSs). In this paper, the processes of non-linear deforming of a DS in cylindrical cavity of a deep bore-hole are considered. On the basis of the theory of curvilinear flexible rods, non-linear constitutive differential equations are deduced. The effects of the longitudinal non-uniform preloading, action of torque and interaction between the DS and the bore-hole surface are taken into account. Owing to the use of curvilinear coordinates in the constraining cylindrical surface and a specially chosen concomitant reference frame, it became possible to separate the desired variables and to reduce the total order of the equation system. To solve it, the method of continuation the solution by parameter and the transfer matrix technique are applied. As a result of the completed numerical analysis, the critical states of the DS loading in the cylindrical channels of inclined bore-holes are found. It is shown that the modes of the post-critical deforming of the DS are associated with its irregular spiral curving prevailing in the zone of bottom-hole-assembly. The possibility of invariant state generation during post-critical deforming is established, condition of its bifurcation is formulated. It is shown that infinite variety of loads can correspond to one geometrical configuration of the DS. They differ each from other by contact force functions.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.4
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• pp.379-389
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• 2000

A cellular automaton is well-known for self-organizing and dynamic behavions in the filed of artifial life. This paper addresses a new neuronic architecture called an evolvable celluar classifier which evolves with the genetic rules (chromosomes) in the non-uniform cellular automata. An evolvable cellular classifier is primarily based on cellular programming, but its mechanism is simpler becaise it utilizes only mutations for the main genetic operators and resmbles the Hopfield network. Therefore, the desirable bit-patterns could be obtained through evolutionary processes for just one individual agent, As a rusult, an evolvable hardware is derived which is applicable to clessification of bit-string information.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.236-240
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• 2000

A cellular automaton is well-known for self-organizing and dynamic behaviors in the field of artificial life. This paper addresses a new neuronic architecture called an evolvable cellular classifier which evolves with the genetic rules (chromosomes) in the non-uniform cellular automata. An evolvable cellular classifier is primarily based on cellular programing, but its mechanism is simpler because it utilizes only mutations for the main genetic operators and resembles the Hopfield network. Therefore, the desirable hi t-patterns could be obtained through evolutionary processes for just one individual agent. As a result, an evolvable hardware is derived which is applicable to classification of bit-string information.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.114-118
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• 2022

The photovoltaic system is affected by various conditions such as temperature and irradiance. Because non-uniform irradiation and partial shading conditions affect the entire string of cells connected in series, a bypass diode is used to bypass the current flow normally. In order to find the maximum power point in partial shade conditions, it is necessary to estimate various methods of maximum power point tracking. In this paper, the hybrid method of MPPT using Lambert W function and perturbation & observation algorithm is proposed under partial shading conditions. The simulation results are obtained using MATLAB/Simulink and shows the improvement of the accuracy of MPPT.

• Journal of the Korean Home Economics Association
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• v.44 no.7 s.221
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• pp.63-72
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• 2006

The purpose of this study was to survey the wearing practices and problems in the working uniform for volunteer fire brigade members and then to develop its design with a improved movement adaptability, physical suitability, ease for equipment accommodation, functionality, convenience and fit. Based on the questionnaire, we have made a testing uniform for volunteer fire brigade members first. Through a subjective analysis for functionality and apparence, we suggested a final design. The final design includes the following elements: 1. It was a two-piece style composed of a jumper and trousers with the upper garments pulled out. Raglan sleeves were used to increase arm's movement scope. Pleats and velcro tapes were attached along the base hem of sleeves to prevent heat transmission. 2. Various types of pockets were attached to secure enough space for keeping things. 3. In trousers, spare space was given at the buttock area with rubber string inserted only at selected part of side lines, and knee pads were attached to prevent wearing out.

• Journal of KIISE
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• v.41 no.9
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• pp.728-743
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• 2014

Finger printing and sequence alignment are well-known approaches for document similarity comparison. A fingerprinting method is simple and fast, but it can not find particular similar regions. A string alignment method is used for identifying regions of similarity by arranging the sequences of a string. It has an advantage of finding particular similar regions, but it also has a disadvantage of taking more computing time. The Multi-Level Alignment (MLA) is a new method designed for taking the advantages of both methods. The MLA divides input documents into uniform length blocks, and then extracts fingerprints from each block and calculates similarity of block pairs by comparing the fingerprints. A similarity table is created in this process. Finally, sequence alignment is used for specifying longest similar regions in the similarity table. The MLA allows users to change block's size to control proportion of the fingerprint algorithm and the sequence alignment. As a document is divided into several blocks, similar regions are also fragmented into two or more blocks. To solve this fragmentation problem, we proposed a united block method. Experimentally, we show that computing document's similarity with the united block is more accurate than the original MLA method, with minor time loss.