• 대한기계학회논문집A
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• 제27권5호
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• pp.742-749
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• 2003

Failure of a pipeline due to local wall thinning is getting more attention in the nuclear power plant industry. Although guidelines such as ANSI/ASME B31G and ASME Code Case N597 are still useful fer assessing the integrity of a wall thinned pipeline, there are some limitations in these guidelines. For instance, these guidelines consider only pressure loading and thus neglect bending loading. However, most Pipelines in nuclear power plants are subjected to internal pressure and bending moment due to dead-weight loads and seismic loads. Therefore, an assessment procedure for locally wall thinned pipeline subjected to combined loading is needed. In this paper, three-dimensional finite element(FE) analyses were performed to simulate full-scale pipe tests conducted for various shapes of wall thinned area under internal pressure and bending moment. Maximum moments based on true ultimate stress(${\alpha}$$\sub$u,t/) were obtained from FE results to predict the failure of the pipe. These results were compared with test results, which showed good agreement. Additional finite element analyses were performed to investigate the effect of key parameters, such as wall thinned depth, wall thinned angle and wall thinned length, on maximum moment. Also, the effect of internal pressure on maximum moment was investigated. Change of internal pressure did not show significant effect on the maximum moment.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.830-833
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• 2007

본 논문에서는 두 개의 17비트 오퍼랜드를 radix-4 Booth's algorithm을 이용하여 곱셈 연산을 수행하는 곱셈기에 대한 효율적인 풀커스텀 디자인에 대한 테스트 방법을 제안하였다. 클럭 속도를 빠르게 하기 위하여 2단 파이프라인 구조로 설계하였고 Wallace tree 부분의 레이아웃을 규칙적으로 하기 위해서 4:2 CSA(Carry Save Adder)를 사용하였다. 회로는 하이닉스반도체의 0.6-um 3-Metal N-well CMOS 공정을 사용하여 칩으로 제작되었다. 제안된 테스트 방법을 사용하여 관찰해야 하는 노드의 수를 약 88% 줄여 효율적으로 고장 시뮬레이션을 수행하였다. 설계된 곱셈기는 9115개의 트랜지스터로 구성되며 코어 부분의 레이아웃 면적은 약 $1135^*1545$ um2 이다. 칩은 전원전압 5V에서 약 24MHz의 클럭 주파수로 동작한다. 제안된 테스트 방법은 풀커스텀 방식의 곱셈기를 비롯한 대부분의 커스텀 설계 회로에 적용이 가능하다.

• Genomics & Informatics
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• 제18권1호
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• pp.5.1-5.5
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• 2020

Highly pathogenic avian influenza (HPAI) viruses have caused severe respiratory disease and death in poultry and human beings. Although most of the avian influenza viruses (AIVs) are of low pathogenicity and cause mild infections in birds, some subtypes including hemagglutinin H5 and H7 subtype cause HPAI. Therefore, sensitive and accurate subtyping of AIV is important to prepare and prevent for the spread of HPAI. Next-generation sequencing (NGS) can analyze the full-length sequence information of entire AIV genome at once, so this technology is becoming a more common in detecting AIVs and predicting subtypes. However, an analysis pipeline of NGS-based AIV sequencing data, including AIV subtyping, has not yet been established. Here, in order to support the pre-processing of NGS data and its interpretation, we developed a user-friendly tool, named prediction of avian influenza virus subtype (PAIVS). PAIVS has multiple functions that support the pre-processing of NGS data, reference-guided AIV subtyping, de novo assembly, variant calling and identifying the closest full-length sequences by BLAST, and provide the graphical summary to the end users.

• 정보처리학회논문지A
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• 제10A권6호
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• pp.671-676
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• 2003

본 논문에서는 고속 병렬 곱셈기에서 속도향상을 위해 부분 곱을 가산하는 과정에 구성되는 CSA(Carry Select Adder) 트리에 새로운 압축기를 적용한 새로운 첫 번째 부분 곱가산(First Partial Product Addition : FPA)를 제안하여 기존의 전가산기를 이용한 병렬가산기보다 부분곱을 계산하는 속도를 약 20% 개선할 수 있게 했다. 새로운 회로는 새로운 FPA 구조를 사용하여 최종 합 CLA 비트를 N/2로 줄인다. 2.5v 0.25um CMOS 기술을 이용하여 제작된 16${\times}$16 곱셈기는 5.14nS의 곱셈 고속을 얻었다. 이 곱셈기의 구조는 파이프라인 설계에 용이하며 고성능을 낸다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권5호
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• pp.430-442
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• 2013

This paper presents a fast multi-reference frame integer motion estimator for H.264/AVC. The proposed system uses the previously proposed fast multi-reference frame algorithm. The previously proposed algorithm executes a full search area motion estimation in reference frames 0 and 1. After that, the search areas of motion estimation in reference frames 2, 3 and 4 are minimized by a linear relationship between the motion vector and the distances from the current frame to the reference frames. For hardware implementation, the modified algorithm optimizes the search area, reduces the overlapping search area and modifies a division equation. Because the search area is reduced, the amount of computation is reduced by 58.7%. In experimental results, the modified algorithm shows an increase of bit-rate in 0.36% when compared with the five reference frame standard. The pipeline structure and the memory controller are also adopted for real-time video encoding. The proposed system is implemented using 0.13 um CMOS technology, and the gate count is 1089K with 6.50 KB of internal SRAM. It can encode a Full HD video ($1920{\times}1080P@30Hz$) in real-time at a 135 MHz clock speed with 5 reference frames.

• Journal of Welding and Joining
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• 제27권1호
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• pp.95-101
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• 2009

In case of manufacturing the high quality welds or pipeline, the full penetration weld has to be made along the weld joint. Thus the root pass welding is very important and has to be selected carefully. In this study, an experimental method for the selection of optimal welding condition was proposed in the root pass welding which was done along the V-grooved butt weld joint. This method uses the response surface analysis in which the width and height of back bead were chosen as the quality variables of the weld. The overall desirability function, which is the combined desirability function for the two quality variables, was used as the objective function for getting the optimal welding condition. In the experiments, the target values of the back bead width and the height are 6mm and zero respectively for the V-grooved butt weld joint of 8mm thickness mild steel. The optimal welding conditions could predict the back bead profile(bead width and height) as 6.003mm and -0.003mm. From a series of welding test, it was revealed that a uniform and full penetration weld bead can be obtained by adopting the optimal welding condition which was determined according to the method proposed.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.108-111
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• 2008

본 논문에서는 동영상의 실시간 Full HD 영상$(1920{\times}1080@30fps)$ 부호화를 위한 하드웨어 기반의 CAVLC 엔트로피 부호화기 구조를 제안한다 한 매크로 블록 당 AC 계수 376개 와 DC 계수 8개 총 384개의 데이터가 존재 할 수 있다. 실시간으로 처리하기 위해서는 최대 384개의 데이터를 모두 처리해야 한다. 데이터를 효율 적으로 처리하기 위해 병렬 처리, 파이프라인 처리를 사용, 블록당 16개의 데이터 이후의 존재하는 불필요한 '0' 제거로 동작 cycle를 최소화하였다. 설계된 모듈은 한 매크로 블록당 최대의 384개의 데이터를 469cycle로 처리한다. CAVLC 구조를 검증하기 위하여 JM 9.4부터 reference C를 개발하였으며, reference C로부터 test vector를 추출하여 설계 된 회로를 검증하였다.

• 한국기계가공학회지
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• 제17권4호
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• pp.17-22
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• 2018

A glove valve regulates the flow in a pipeline as a kind of control valve. However, when the disc and seat contact, the valve structure can be distorted and flow can leak due to the elongation of the valve material under high pressure. The surface texture is not good enough to seal the contact surface (in practice) because the lapping process is usually done manually. Furthermore, assembly performance is analyzed by structural analysis. Compared with a standard seat, the newly designed seat had a smaller radial deformation and a larger longitudinal deformation. Therefore, the newly designed seat can maintain a tight and uniform contact with the disc with a reduced radial deformation and an expanded available seal area with an increased longitudinal deformation. The seal performance of the glove valve has been improved in a cost-effective manner.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3342-3351
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• 2023

High-density polyethylene (HDPE) pipelines in nuclear power plants (NPPs) have to meet high requirements for seismic performance. HDPE pipes have been proved to have good seismic performance, but joints are the weak links in the pipelines, and pipeline failures usually initiate from the defects inside the joints. Limited data are available on the seismic performance of butt-fusion joints of HDPE pipelines in NPPs, especially in terms of defects changes inside the joints after earthquakes. In this paper, full-scale shaking table tests were performed on a test section of suspended HDPE pipelines in an NPP, which included straight pipes, elbows, and 10 butt-fusion joints. During the tests, the seismic load-induced strain of the joints was analyzed by strain gauges, and it was much smaller than the internal pressure and self-weight-induced strain. Before and after the shaking table tests, phased array ultrasonic testing (PA-UT) was conducted to detect defects inside the joints. The locations, numbers, and dimensions of the defects were analyzed. It was found that defects were more likely to occur in elbows joints. No new defect was observed after the shaking table tests, and the defects showed no significant growth, indicating the satisfactory seismic performance of the butt-fusion joints.

• Advances in Energy Research
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• 제2권2호
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• pp.61-72
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• 2014

This paper's aim is to do a global evaluation (considering four dimensions: technical-economic, environmental, social and political) in the ways of natural gas transportation (gas pipelines, GNL and GTL) and electric transmission, in order to supply the energy demands of Mato Grosso do Sul, a brazilian state. The transport ways had been compared between itself using a software of decision taking (Decision Lens Suite), which determined a better way for transporting natural gas in this case. In a generalized manner the gas pipeline is the best way of transporting natural gas, therefore it takes advantage in the majority of the analyzed dimensions.