• Nuclear Engineering and Technology
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• 제55권3호
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• pp.999-1008
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• 2023

Deformed fuel rods can cause a partial blockage of the flow area in a subchannel. Such flow blockage will influence the core coolant flow and further the core heat transfer during the reflooding phase and subsequent severe accidents. Nevertheless, most of the system analysis codes simulate the accident process based on the assumed flow blockage ratio, resulting in inconsistencies between simulated results and actual conditions. This paper aims to study the influence of flow blockage in severe accident scenario of the CAP1400 reactor. First, the flow blockage model of ISAA code is improved based on the FRTMB module. Then, the ISAA-FRTMB coupling system is adopted to model and calculate the QUENCH-LOCA-0 experiment. The correctness and validity of the flow blockage model are verified by comparing the peak cladding temperature. Finally, the DVI Line-SBLOCA accident is induced to analyze the influence of flow blockage on subsequent CAP1400 reactor core heat transfer and core degradation. From the results of the DVI Line-SBLOCA accident analysis, it can be concluded that the blockage ratio is in the range of 40%-60%, and the position of severe blockage is the same as that of cladding rupture. The blockage reduces the circulation area of the core coolant, which in turn impacts the heat exchange between the core and the coolant, leading to the early failure and collapse of some core assemblies and accelerating the core degradation process.

• 토지주택연구
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• 제10권1호
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• pp.1-7
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• 2019

This article assumes that the first newtown has declined in Korea. Urban regeneration projects should be implemented for regeneration for CBD in Newtown as well as small local cities. The purpose of this article is to analyze the character of the subway area and to suggest the key issues for regeneartion in the subway area. Especially focussing on the local important commercial function in 5 subway areas. As a result of analyzing 5 subway areas according to basic statistical data, field interviews, and legal decline diagnostic index, all five commercial districts showed decline. In particular, the decline of Baekseok Station area appears to be serious, and there is a key factor that attracts the decline of the commercial area such as the long - term building or the closure rate of each commercial area. In addition, the vacancy rate is increasing due to large distribution facilities in new cities, the entry of new floating facilities on the outskirts, and unsold new stores, and the recession is accelerating. In this way, the signs of decline in the core of the new city are enriched, but the current Urban Regeneration Act is a legal system with a policy goal of regeneration of small and medium cities in the provinces as a system to promote the function of core bases rather than the overall redevelopment of new cities. Therefore, preemptive response is needed for the regeneration in those areas.

• 한국콘텐츠학회논문지
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• 제10권10호
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• pp.398-407
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• 2010

강화도라는 핵심 관광 목적지를 선택하는 관광객의 유형을 실증조사를 통해 분석하여 인접지역인 김포서 북부지역의 개발방향을 제시하려는데 본 연구의 목적이 있었다. 이들 관광객을 흡수하기 위해 공간적 연계를 어떻게 만들어 가야 할지가 본 논문의 연구과제 이었다. 이런 면에서 수도권 시민의 관광욕구를 충족시키고 수용하기 위해서는 핵심관광 지역을 방문하는 관광객에 대한 구체적인 분석 자료를 근거로 핵심 관광지 및 인근 연계지역 관광자원 개발 전략을 구상함으로써 차별화된 경쟁력을 도모할 수 있다. 강화도와 김포 서북부지역을 대상으로 관광자원의 분포와 접근성, 관광객 행태에 대한 연구를 통하여 지리적 공간요소의 중요성을 재발견 할 수 있다. 각 지역별로 지역의 관광자원 특성에 관한 실증적인 연구가 증가하고 있으며, 특히 지역단위의 미시적 연구가 증대하고 있는 시점에서 본 연구는 핵심관광 목적지인 강화도의 관광객 유형을 분석하여 인근지역인 김포서북부지역의 관광자원을 연계 개발시켜나갈 방안을 모색하려 한다.

• 소성∙가공
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• 제14권2호
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• pp.147-152
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• 2005

The objective of this study is to develop an optimal drawing die for the clad wire drawing process. Cu-clad wire, which has the advantages of the high strength of a steel core and the electro-conductivity, corrosion resistance of a copper layer, is widely being used in the field of the telecommunications, electric-electronic and military technology industries. It is important to obtain uniformly coated rate when producing clad wires. Drawing process of clad wire will be influenced on damage and coated rate of core and sleeve for process variables such as semi-die angle and reduction in area. Therefore, in this study, the finite-element result obtained in this study was analyzed to the effect of the various forming parameters, which included the semi-die angle and reduction in area. The coated rate will be predicted with observation of copper coated rate variation according to total reduction in area and the optimal pass schedule will be set up through proper reduction in area and semi-die angle variation.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권3호
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• pp.293-299
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• 2016

Recently, as IoT (Internet of Things) becomes more important, low cost implementation of sensor nodes also becomes critical issues for two well-known standards, IEEE 802.15.4 and IEEE 802.15.6 which stands for WPAN (Wireless Personal Area Network) and WBAN (Wireless Body Area Network), respectively. This paper presents the area-optimized AES-CCM (Advanced Encryption Standard - Counter with CBC-MAC) hardware security engine which can support both IEEE 802.15.4 and IEEE 802.15.6 standards. First, for the low cost design, we propose the 8-bit AES encryption core with the S-box that consists of fully combinational logic based on composite field arithmetic. We also exploit the toggle method to reduce the complexity of design further by reusing the AES core for performing two operation mode of AES-CCM. The implementation results show that the total gate count of proposed AES-CCM security engine can be reduced by up to 42.5% compared to the conventional design.

• 한국콘텐츠학회논문지
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• 제8권9호
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• pp.27-33
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• 2008

Linux에서 사용되는 Shared Memory는 동일한 메모리 영역에 여러 개의 프로세스가 접근할 수 있도록 해 주는 기술이다. 본 논문은 Linux 운영체제에서 지원해 주는 System V의 IPC 중 하나인 Shared Memory를 Dual Core 시스템 상에서 동작하도록 구현한다. 본 논문에서는 커널 단계에서 처리되는 SVR(System V Release) 형식의 Shared Memory를 다룬다. 기존의 공유메모리 방식은 단일 처리기를 이용한 방식이다. 본 논문에서는 dual core를 이용하여 공유메모리 처리를 할 수 있는 시스템을 제안한다. 본 논문에서 제안하는 Dual Core 시스템에서 공유 메모리 기능 구현은 기존의 단일 처리기 시스템에서보다 성능을 향상시킬 수 있도록 한다. 공유 메모리를 이용한 프로세스의 동작이 별개의 CPU에서 동작되도록 함으로써 성능 향상을 꾀한다.

• 열처리공학회지
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• 제16권4호
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• pp.197-204
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• 2003

Honeycomb structure has been fabricated by brazing method using 0.1 wt%C and 1.0wt%C carbon steel core and STS304 stainless steel face sheet. Core shear strength ratio in W and L directions was 1:1.03 in 7 mm cell size, whereas 1:1.45 in 4 mm cell size. Flexural strength on face sheet was 166.4 MPa (0.1 wt%C, W direction), 171.1 MPa (0.1 wt%C, L direction), and 120.2 MPa (1.0 wt%C, W direction) in 7 mm cell size. And in 4mm cell size specimen, it was 169.2 MPa (0.1 wt%C, W direction), 224.2 MPa (0.1 wt%C, L direction). This means that flexural strength of 0.1 wt%C core material was higher than that of 1.0wt%C core material, which was contrary to expectation. SEM and EDS analysis represented that grain boundary diffusion had occurred in0.1 wt%C core, but no grain boundary diffusion in 1.0 wt%C core. And corrugated surface of 0.1 wt%C core was flat, whereas that of 1.0 wt%C core was not flat. As a result, contact area between two 1.0 wt%C cores was much less than that of 0.1 wt% cores, It is thought to be main reason for lower flexural strength of 1.0 wt%C core.

• Structural Engineering and Mechanics
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• 제74권3호
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• pp.395-406
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• 2020

Many prefabricated concrete frame joints have been proposed, and most of them showed good seismic performance. However, there are still some limitations in the proposed fabricated joints. For example, for prefabricated prestressed concrete joints, prefabricated beams and prefabricated columns are assembled as a whole by the pre-stressed steel bar and steel strand in the beams, which brings some troubles to the construction, and the reinforcement in the core area of the joints is complex, and the mechanical mechanism is not clear. Based on the current research results, a new type of fabricated joint of prestressed concrete beams and confined concrete columns is proposed. To study the seismic performance of the joint, the quasi-static test is carried out. The test results show that the nodes exhibit good ductility and energy dissipation. According to the experimental fitting method and the "fixed point pointing" law, the resilience model of this kind of nodes is established, and compared with the experimental results, the two agree well, which can provides a certain reference for elasto-plastic seismic response analysis of this type of structure. Besides, based on the analysis of the factors affecting the shear capacity of the node core area, the formula of shear capacity of the core area of the node is proposed, and the theoretical values of the formula are consistent with the experimental value.

• 인간식물환경학회지
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• 제24권1호
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• pp.95-105
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• 2021

Background and objective: A biosphere reserve is a complex concept that combines the preservation of biodiversity and the sustainable development with the region, outstanding ecosystems with worth conserving in worldwide. The purpose of this study is to suggest the way of zoning that can perform the functions of conservation, development, and logistics support of biosphere reserves. Methods: To meet the purpose of this study, the designation criteria, restrictions, and permissions of the protected area specified in the law for domestic protected areas were reviewed to classify the functions of a biosphere reserve. Results: Through this classification, 10 domestic protected areas with high ecological protection value, such as the natural beauty of the ecosystem, biodiversity, and habitats for wild animals and plants were derived as the core areas of the biosphere reserves. Also, a total of 21 protected zones that can function as a buffer to protect the core of the natural ecosystem from indiscriminate development such as resource protection, recovery, pollution prevention, and improvement were derived as appropriate sites for a buffer. In the review process, issues such as different behavioral restrictions and ranges of permission due to the application of different laws were identified, if two or more protected areas exist within one of the protected areas, there is a protected area that does not meet the criteria for designating use zone, or where behavior restrictions do not meet the zoning criteria of biosphere reserve, under the laws of domestic protected areas. Conclusion: Although this study was not able to carefully review most of the laws on domestic protected areas that are linked to other laws, it was able to categorize appropriate domestic protected areas that can act as the core and buffer zones of biosphere reserves.

• 대한임베디드공학회논문지
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• 제8권2호
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• pp.87-93
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• 2013

In this paper, we implemented and evaluated the performance of a vector-based rasterization algorithm of 3D graphics using a SIMD-based many-core processor that consists of 4,096 processing elements. In addition, we compared the performance and efficiency of the rasterization algorithm using the many-core processor and commercial GPU (Graphics Processing Unit) system which consists of 7 GPUs and each of which have 512 cores. Experimental results showed that the SIMD-based many-core processor outperforms the commercial GPU system in terms of execution time (3.13x speedup), energy efficiency (17.5x better), and area efficiency (13.3x better). These results demonstrate that the SIMD-based many-core processor has potential as an embedded mobile processor.