• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
• /
• pp.229-233
• /
• 2003

This paper describes a practical formulation of Non-Bernoulli-Compatibility Truss Model. Not only equilibrium conditions but also some approximations are employed to solve for the unknowns included in the proposed model. By assuming that the ratio of $V_a$ to V remains to be constant along the shear span, the relationship between $\alpha$ and z is mathematically established as an arch shape function. $V_m$ is also approximated to be an empirical value that is equal to the least membrane shear strength. The coefficient a is made utilizing a nonlinear finite element analysis. The adequacy of the model is examined by test results available in literatures, and the predicted values are shown to be in excellent agreement with the experimental results.

• 대한전자공학회논문지
• /
• 제26권1호
• /
• pp.10-19
• /
• 1989

본 논문에서는 깊이데이타를 이용한 물체의 조형방법을 제안한다. 입력으로 들어온 깊이데이타에서 물체의 형상특징을 추출하기 위하여 $2{\times}2$ 마스크내에서 깊이변화율을 고려한 Z축 기울기를 정의하여 각각의 원시도형(primitive)마다 가지는 크기와 방향특성을 이용하여 표면을 분류한다. 또한 여러개의 원시도형들의 조합으로 되어있는 물체에서는 핵심점을 정의하여 각 원시도형을 분리한다. 나아가 표면영역들간의 공간상의 위치관계를 구하여 인식을 위한 원시도형들간의 상관관계를 추출하였으며 제안된 방법의 유용성을 실험에 의하여 입증한다.

• 호남수학학술지
• /
• 제21권1호
• /
• pp.157-169
• /
• 1999

For a k-connected inverse system $({\scr{X}},\;*)=((X_{\lambda},\;*),p_{{\lambda}{{\lambda}}^{\prime}},\;{\Lambda})$ of pointed topological spaces and pointed preserving weak fibrations, inducting epimorphic chain maps, over a directed set, we show that the homotopy group ${\pi}_k(lim{\scr{X}},\;*)$ of the inverse limit is isomorphic to the integral homology group $$H_k(lim{\scr{X}};\mathbb{Z})$. Using the result of S. $Marde{\check{s}}i{\acute{c}}$, we prove that the group of pure extension $Pext(colimH^n({\scr{X}},\;A)$ is isomorphic to the group of extension $Ext({\Delta}({\lambda}),\;Hom(H^n({\scr{X}}),\;A))$.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집A
• /
• pp.734-739
• /
• 2001

In this paper, we develop a six-axes machining center tool(MCT) and CAD/CAM system. The MCT consists of two mechanical parts, i.e., a X-Y-Z Cartesian coordinate typed MCT and a parallel-typed tilting table. Kinematics and singularity are accomplished to design the parallel-typed tilting table, and CAD/CAM system is developed for the six-axes MCT, which requires the commands of position as well as orientation for machining of complex shape. The CAD/CAM system has a tool path generator, a NC code generator and a graphic simulator. This paper designs the parallel-typed tilting table to meet the desired specification and presents the results of tool path, NC code and graphic simulation.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.531-534
• /
• 1997

A design system of dies for hot extrusion of structural shapes such as Z' s, L' s, T' s, U' s and H' s from aluminum alloys was developed in this study. The developed design system of dies is based of established die design rule system. The design rules for die design are obtained from the handbooks, plasticity theories and relevant references. The environment of the system is AutoCAD and AutoLISP, the graphic programming language was used for the configuration of the system. This system includes five major modules such as section shape design module, die opening number module. die opening layout module, die correction module and die bearing design module that are used to determine design variables. This system would be used to design of dies for hot extrusion from aluminum alloys and widely used in manufacturing course..

• 천문학회보
• /
• 제43권1호
• /
• pp.38.1-38.1
• /
• 2018

With upcoming high-quality data from surveys such as eBOSS or DESI, improving the theoretical modeling and gaining a deeper understanding of the effects of neutrinos and dark radiation on structure formation at small scales are necessary, to obtain robust constraints free from systematic biases. Using a novel suite of hydrodynamical simulations that incorporate dark matter, baryons, massive neutrinos, and dark radiation, we present a detailed study of their impact on Lyman-Alpha forest observables. In particular, we accurately measure the tomographic evolution of the shape and amplitude of the small-scale matter and flux power spectra and search for unique signatures along with preferred scales where a neutrino mass detection may be feasible. We then investigate the thermal state of the intergalactic medium (IGM) through the temperature-density relation. Our results indicate that the IGM at z ~ 3 provides the best sensitivity to active and sterile neutrinos.

• 대한기계학회논문집A
• /
• 제33권3호
• /
• pp.224-230
• /
• 2009

FIB has been commonly used as a very powerful tool in the semiconductor industry. It is mainly used for mask repair, device correction, failure analysis and IC error correction, etc. Currently, FIB is not being applied to the fabrication of the micro and nano-structured mold, because of low productivity. And also sputtering rate has been required to fabricate 3D shape. In the paper, we studied the FIB-Sputtering rate according to mold materials. And surface roughness characteristics had been analysed for micro or nano mold fabrication. Si wafer, Glassy Carbon, STAVAX and DLC that have been normally considered as good micro or nano mold materials were used in the study.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 추계학술대회논문집
• /
• pp.342-345
• /
• 2004

A combination of deep drawing and cold forging process is tried to achieve near net shaping of automatic transmission part which has drum shape and thickness variation. It is key for successful shaping of the part to find out proper condition to combine two different forming methods. Finite element analysis can be utilized for that purpose effectively. Integrity, reliability, and durability of the part are improved by eliminating machining process. The developed process is applied in real manufacturing process successfully.

• 한국정밀공학회지
• /
• 제19권1호
• /
• pp.135-142
• /
• 2002

Input shaping is a method for reducing residual vibration in computer controlled machines. Vibration is eliminated by convolving a sequence of impulses, an input shaper, with a desired system command to produce a shaped input. This paper shows the shape of sensitivity curve of input shaper as impulse interval T and analysis of robustness for input shaper on the z-plane. And a method is presented for designing equivalent input shaper considering sampling time $T_s$. And then we applied equivalent input shaper to crane system.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 춘계학술대회 논문집
• /
• pp.445-450
• /
• 1995

This paper deals with conversion from STL file to Slice cross-sectional information for Stereolithography. The STL file consist of three vertices of triangle and normal vectors in order to represent three dimension shape, but It is very difficult to convert STL file intoSlice file directly, because of file size from one Mbyte to tens of Mbytes. So, The system is accomplished data flow such as neutral.dat, .SL1, .SL2, .SL3, and .SLC file. The data processing is as follows: 1. Create a neutral file including common information. 2. Modify STL file within effective scope of SLA. 3. Calculate a point of intersection between plane equation and line equation. 4. Sort z values by increasing order. 5. Search closed loop by method of singlylinked linear list. The system is developed by using Borland C++ 3.1 compiler in the environment of Pentium PC. We get a satisfactory prototype as a result of application about a lot of household electrical appliances.