• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.5
• /
• pp.859-864
• /
• 2013

Creation of a stress relief groove is a fairly simple yet high-performance method. During the application of this method, it is important to consider the location and size of the groove in order to achieve better performance. Consequently, this research proposes an approach for optimizing the application of the stress relief groove method to a press-fitted assembly. In a boss design, the position and diameter of the groove are configured as design variables and the design of experiments is applied. Based on this information, a 3D model is built and analyzed using the finite element analysis software ABAQUS. Meta-models are created using back-propagation neural networks. Then, deterministic optimization results obtained from a genetic algorithm are compared with the results of the finite element analysis. The temperature sensitivity of the optimized model is analyzed, and finally, reliability-based design optimization is conducted for enhancing the design quality.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.7
• /
• pp.559-564
• /
• 2016

The objectives of this paper are to develop a finite element analysis model to analyze press-fitted and bending load conditions in a press-fitted assembly, and propose a hub shape optimization method to minimize contact pressure near the shaft contact edge. Numerical asymmetric-axisymmetric finite element models have been developed to predict contact stress on press-fitted shafts. The global optimization method, genetic algorithm, local optimization method, and sequential quadratic programming were applied to a press-fitted assembly to optimize the hub contact edge geometry. The results showed that the maximum contact pressure with the optimized hub shape decreased more than 60 % compared to conventional hubs and the maximum contact stress affecting fatigue life was reduced about 47 %. Hub shape optimization can be useful to increase the load capability of press fits in terms of wear and fatigue behavior.

• Structural Engineering and Mechanics
• /
• v.4 no.2
• /
• pp.139-148
• /
• 1996

Vector algorithms and the relative importance of the four basic modules (computation of element stiffness matrices, assembly of the global stiffness matrix, solution of the system of linear simultaneous equations, and calculation of stresses and strains) of a finite element computer program for inelastic analysis of reinforced concrete shells are presented. Performance of the vector program is compared with a scalar program. For a cooling tower problem, the speedup factor from the scalar to the vector program is 34 for the element stiffness matrices calculation, 25.3 for the assembly of global stiffness matrix, 27.5 for the equation solver, and 37.8 for stresses, strains and nodal forces computations on a Gray Y-MP. The overall speedup factor is 30.9. When the equation solver alone is vectorized, which is computationally the most intensive part of a finite element program, a speedup factor of only 1.9 is achieved. When the rest of the program is also vectorized, a large additional speedup factor of 15.9 is attained. Therefore, it is very important that all the modules in a nonlinear program are vectorized to gain the full potential of the supercomputers. The vector finite element computer program for inelastic analysis of RC shells with layered elements developed in the present study enabled us to perform mesh convergence studies. The vector program can be used for studying the ultimate behavior of RC shells and used as a design tool.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.8
• /
• pp.19-23
• /
• 2001

DSP-based implementation is pervasive in wireless communication parts for systems and handsets according to developing high-speed and low-power programmable Digital Signal Processor (DSP). In this paper, we present a real-time implementation of multi-channel Adaptive Multi-rate (AMR) speech coder. The real-time implementation of an AMR algorithm is achieved using 32-bit fixed-point TMS320C6202 DSP chip that operates at 250 MHz. We performed cross compile, linear assembly optimization and TMS320C62xx assembly optimization for real-time implementation. Furthermore, speech data input/output function and communication function with external CPU is included in an AMR speech coder. The AMR Speech coder developed using DSP EVM board was evaluated in ETRI IMT-2000 Test-bed system.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.3
• /
• pp.276-282
• /
• 2015

This paper proposes a SMD (surface mounting device) classification method for the PCB assembly inspection machines. The package types of SMD components should be classified to create the job program of the inspection machine. In order to reduce the creation time of job program, we developed the automatic classification algorithm for the SMD packages. We identified the chip-type packages by color and edge distribution of the images. The input images are transformed into the HSI color model, and the binarized histroms are extracted for H and S spaces. Also the edges are extracted from the binarized image, and quantized histograms are obtained for horizontal and vertical direction. The neural network is then applied to classify the package types from the histogram inputs. The experimental results are presented to verify the usefulness of the proposed method.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06b
• /
• pp.357-359
• /
• 2012

초 고성능 바이오 서열 분석 장비 기술의 발달로 대량의 바이오 정보가 쏟아져 나오고 있으며, 바이오산업의 발달로 개인별 유전체 정보에 의한 맞춤의학의 시대가 도래되고 있다. 수많은 서열에 대한 분석에는 많은 저장장치 및 주기억장치가 필요하므로 슈퍼컴퓨터 급의 서버와 대량의 데이터를 빠르게 처리할 수 있는 프로그램이 필요하다. 이러한 분석에는 염기서열 일치 검색과 이를 기반으로 하는 Alignment와 Assembly 분석이 있으며, 이를 수행하는 기존의 알고리즘 및 대부분의 프로그램들은 염기서열을 문자열로 취급하고, 해쉬 인덱스 테이블, Brujin 그래프의 사용, 버러우즈 휠러 변환(BWT) 등의 기법을 활용하여 효율적인 분석을 도모하였다. 본 논문에서는 염기서열을 문자열이 아닌 k-mer 묶음의 정수형 하나로 변환하여 검색함으로써 저장 공간의 크기를 약 28% 이상으로 줄이고 형 변환 상태에서의 검색을 수행할 수 있는 알고리즘을 제안한다. Assembly 분석 프로그램인 CalcGen 프로그램을 개발하여 본 알고리즘의 효용성 및 효율성을 실험을 통해 검증하였다. 이 연구의 결과는 향후 대량의 유전체 염기서열의 효율적 분석과 저장 및 처리에 또 하나의 새로운 접근 방법을 제안하는데에 그 의미를 둘 수 있다.

• Korean Journal of Microbiology
• /
• v.35 no.2
• /
• pp.121-127
• /
• 1999

An effective computer program for assembling fragments in DNA sequencing has been developed. The program, called SeqEditor (Sequence Editor), is usable on the pcrsonal computer systems of MS-Widows which is the mosl popular operating system in Korea. It c'm recd several sequence file formats such as GenBak, FASTA, and ASCII. In the SeqEditor program, a dynamic programming algorihm is applied to compute the maximalscoring overlapping alignment between each pjlr of fragments. A novel feature of the program is that SeqEdilor implemnents interaclive operation with a graphical user interface. The performance lests of the prograln 011 fragmen1 data from 16s and 18s rDNA sequencing pi-ojects produced saiisIactory results. This program may be useful to a person who has work of time with large-scale DNA sequencing projects.

• Nuclear Engineering and Technology
• /
• v.33 no.1
• /
• pp.25-33
• /
• 2001

To determine the pin power distribution without disassembling, HANARO fuel assemblies are gamma-scanned and then the distribution is reconstructed tv using the tomography method. The iterative least squares method (ILSM and the wavelet singular value decomposition method (WSVD) are chosen to solve the problem. An optimal convergence criterion is used to stop the iteration algorithm to overcome the potential divergence in ILSM. WSVD gives better results than ILSM , and the average values from the two methods give the best results. The RMSE (root mean square errors) to the reference data are 5.1, 6.6, 5.0, 6.5, and 6.4% and the maximum relative errors are 10.2, 13.7, 12.2, 13.6, and 14.3%, respectively. It is found that the effect of random positions of the pins is important. Although the effect can be accommodated by the iterative calculations simulating the random positions, the use of experimental equipment with a slit covering the whole range of the assembly horizontally is recommended to obtain more accurate results. We made a new apparatus using the results of this study and are conducting an experiment in order to obtain more accurate results.

• Nuclear Engineering and Technology
• /
• v.53 no.12
• /
• pp.4166-4178
• /
• 2021

The Control Rod Drive Mechanism (CRDM) is an essential part of the reactor, which realizes the start-stop and power adjustment of the reactor by lifting and lowering the control rod assembly. As a moving part in CRDM, the latch directly contacts with the control rod assembly, and the life of latch is closely related to the service life of the reactor. In this paper, the relationship between the life of the latch and the step stress, friction stress, and impact stress in the process of movement is analyzed, and the optimization methodology and process of latch life based on the approximate model are proposed. The design variables that affect the life of the latch are studied through the experimental design, and the optimization objective of design variables based on the latch life is established. Based on this, an approximate model of the life of the latch is built, and the multi-objective optimization of the life of the latch is optimized through the NSGA-II algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.6
• /
• pp.1163-1168
• /
• 2001

The ranging systems measure range data in three-dimensional coordinate from target surface. These non-contact remote ranging systems is widely used in various automation applications, including military equipment, construction field, navigation, inspection, assembly, and robot vision. The active ranging systems using time of flight technique or light pattern illumination technique are complex and expensive, the passive systems based on stereo or focusing principle are time-consuming. The proposed algorithm, that is based on cross correlation of projection profile of vertical edge, provides advantages of fast and simple operation in the range acquisition. The results of experiment show the effectiveness of the proposed algorithm.