• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.2
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• pp.57-68
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• 2004

We present a new parallel algorithm for extending the domain of a UOWHF. Our algorithm is based on non-complete l-ary tree and has the same optimal key length expansion as Shoup's which has the most efficient key length expansion known so far. Using the recent result [8], we can also prove that the key length expansion of this algorithm and Shoup's sequential algorithm are the minimum possible for any algorithms in a large class of "natural" domain extending algorithms. But its prallelizability performance is less efficient than complete tree based constructions. However if l is getting larger then the parallelizability of the construction is also getting near to that of complete tree based constructions.tructions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.265-271
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• 2003

This study is for the stable optical source in order to get the precision measurement, which contributes to help the laser frequency and the output to be settled. The laser optical frequency is changed by the length of resonance cavity. The length variation of the laser resonance amplitude is affected by the thermal expansion of that system. So, we try not only to adjust the temperature of the laser tube using the heater for fine length of resonance cavity, but also to maintain the fixed temperature of the resonance cavity for outputting the safe laser optical frequency. Therefore, we must take materials with the thermal expansion of the supporting system, which is closer to it of the laser resonance cavity. Using the materials, we can promote to stabilize the temperature of it. In advance, we also plan to get the settlement of the laser frequency and the output in the long km, optimizing and stabilizing the system.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.5
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• pp.852-859
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• 1996

The factors and mechanism of arm surface changes were analyzed by regression analysis for the relationship between changes in arm joint angle and arm surface changes, according to the direction of upper extremity motion. Body surface change patterns among subjects were tested also. Experiments were carried out on 3 female subjects of different body types to examine 26 motions in 4 directions for 4 upper extremity parts. The major conclusions of the study are as follows: 1. The expansion or contraction of arm surface length depends on the direction of upper extremity motion. 2. Arm surface length changes by linear expansion or contraction according to the joint angle of the direction of motion. The mechanism of arm surface changes is represented by a linear relation between arm surface changes and the (actors of the direction of upper extremity motion and arm joint angle. 3. Arm surface length shows the same pattern of body surface changes regardless of body type. A quantitative model of body surface changes at upper extremity should be developed for functional sleeve design.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.781-787
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• 2004

Where the track is continuously welded over a bridge, the longitudinal force is interacted between the track and the sub-structure. Due to this respect, the expansion joint is used to decrease this force. But the expansion joint has several problems related to passenger comfort and maintenance etc. In this study, it is analysed about how the stability of the track is affected as the span length becomes longer in case of 2-span continuos bridge. It is found that there is no problem of an stability unless the span length is longer than 90m when the elastic shoe is used. And several parametric studies were also implemented.

• Journal of the Korean Society for Railway
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• v.7 no.3
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• pp.283-289
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• 2004

According to continuos welded rails on a bridge, temperature changes bring about the expansion of the bridge deck adding axil forces on the track. Moreover, the ballast on the bridge deck expansion joint is moved due to the bridge deck. If bridge decks are longer, the influence is greater, loosening ballast, causing track irregularities, and deteriorating passengers' comfort. Considering structure of bridge itself and tolerance of track irregularities caused by the loosened ballast on bridges, the maximum length of a deck should be less than 80m, which is the same as the standard of the French railway. In this study, an interaction between the expansion related to the bridge length and irregularity in longitudinal level referring to measurements and maintenance works performed in the high-speed railways was analyzed. This research shows that installation of sliding plate or vertical ballast stopper is not a good option since it is difficult to install. On the other hand, installation of movable fastener or gluing is easy but its influence is insignificant. To conclude, switch tie tamping or manual tamping is more effective than others.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1050-1055
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• 2008

The demand on a turnout layed on a bridge is rising owing to the increasing number of stations on the viaduct. And also the demand on a turnout with CWR is rising to upgrade running speed of the passing train. A CWR with turnout is subjected to additional axial force induced by the thermal expansion of bridge as well as lead rail of turnout. The additional axial force is closely related with the distance between bridge expansion joint and turnout when it is located near the movable bearing of bridge, and it is required to keep some distance to prevent excessive axial stress in CWR. But, there is no guideline in specification for the proper distance from E.J. to turnout, and it caused problem in planning turnout or bridge. So, it this study, the parametric study to investigate the effect on axial stress in CWR with turnout according to span length and distance between bridge expansion joint and turnout was performed. From the results of numerical analysis, it was found out that $5{\sim}30m$ distance is required to prevent excessive axial in CWR for span length less 90m.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.147-151
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• 2010

Since the kinetic energy is dissipated through plastic deformation energy generated in expanding process of the tube by a die. In order to successfully absorb the kinetic energy there should be no buckling in the expansion tube during expanding process. The buckling instability of the expansion tubes is affected by the initial boundary conditions, tube thickness and length. In this study, the effects of the tube thickness except length and initial boundary condition on the buckling instability are studied using a finite element method. In addition, Analysis procedure for nonlinear post-buckling analysis of expansion tube is established. There are three kinds of finite element analysis procedures for buckling analysis of expansion tube, quasi-static analysis, linear buckling analysis and nonlinear post-buckling analysis. The effect of the geometry imperfections defined as linear superimposition of buckling modes is considered in the nonlinear post-buckling analysis. The results of finite element analysis indicate that the buckling load increase with increase of thickness of tube and geometry imperfection. Finial buckling shapes are changed with respect to the geometry imperfection.

• Journal of the Korean Institute of Rural Architecture
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• v.20 no.2
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• pp.11-18
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• 2018

The purpose of this study is to analyze the structure and use change of the private space according to the balcony expansion and use it as the data of plan design. According to Bay, front length/width ratio and the change of balcony space before and after expansion of space organization of house units were analyzed. Common characteristics of Flat type and Tower type are an increase of the frontage length of house units in an apartment, an increase of the number of front bay, and an increase of integrated LDK focusing on living room. A difference is that Flat type shows high frontage ratio, Bay figure, and spatial arrangement favorable to front openness and lighting. Flat type shows higher area distribution than Tower type in LDK area distribution located in at the plane center. Spatial expandability and visual openness of Flat type are more beneficial than those of Tower type in the planning, and a balcony extension of house units has developed to direction to open more. Tower type creates various block images through a combination of house units focusing on the core. Uses after balcony expansion are area expansion of a balcony-neighboring room, storage space, expansion and function improvement of the variable range, and specialized space different from a neighboring room. In addition, there is no escapable space except for a shelter, so unit plan should be prepared to prevent using it other space of a shelter and to solve moving line of two-way horizontal refuge and vertical refuge.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.348-353
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• 2007

This paper presents design specifications and characteristics of bridge expansion joints to develop new type-joints in fiber reinforced polymer decks. Based on properties of the fiber reinforced polymer decks and fundamental process to calculate their expansion length, new expansion joints fur fiber reinforced polymer decks on typical steel or concrete girder are developed and proposed.

• Journal of the Korean Home Economics Association
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• v.23 no.3
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• pp.1-8
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• 1985

This study is an ergonomic study on the function of sleeves related with the expansion and contraction of the upper Extremity skin surface by various movememts. RESULTS : 1. According to the plane figure, a. The change of form is like fig. 3. b. In the changing rates of the expansion and contraction of skin surface by various movements, that of arm hole girth shows an extremely big discrepancy and that of Elbow Girth shows a relative low one. c. According to the rate of the expansion and contraction of each block, the inside of the upper arm area expands most in all the blocks measured. 2. According to the rate of expansion and contraction of skin surface by somatometry, inside lehgth of arm in M\sub 2\ and outside length of the upper arm in M\sub 4\ expand significantly8and also elbow girth in M\sub 6\, M\sub 7\, M\sub 8\ expands significantly.