• Journal of the Korean Data and Information Science Society
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• v.28 no.3
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• pp.473-481
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• 2017

It is well known that the air quality of 92% of the world is known to exceed the standard of WTO and the death caused by air pollution is almost 6 million per year. The $PM_{2.5}$ concentration in Korea is the second most serious among the OECD countries following Turkey. Since the $PM_{2.5}$ has a direct effect on the respiratory system, it has been actively studied in domestic and foreign countries. But current research on the $PM_{2.5}$ is limited in weather factor or air pollutants. In this paper, we consider the influence of spatial neighbor with weather factor or air pollutants using spatial panel model. We applied the proposed method to 25 borough of Seoul in Korea. The result shows a significant effect of spatial neighbor on the $PM_{2.5}$ concentration fields.

• The Journal of the Acoustical Society of Korea
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• v.19 no.1
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• pp.61-66
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• 2000

In this paper, we are proposing an efficient 3D source localization algorithm using 3 uniform linear subarrays. The proposed algorithm replaces 3D search required in conventional 3D MUSIC algorithm with 3 1D searches, and thus reduces computational burden. The estimate of the 1D conic angle obtained from a subarray under the far-field assumption satisfies a nonlinear algebraic equation of the true source bearing angle, elevation angle, and range. The proposed algorithm estimates source location by solving 3 algebraic equations obtained from 3 subarrays. Comparing 3D MUSIC spectrums of the estimated source locations, the proposed algorithm solves pairing problem for multiple sources localization.

• Journal of Chest Surgery
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• v.40 no.3 s.272
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• pp.180-192
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• 2007

Background: As determined from the recent investigations of discordant cardiac xenotransplantation, hyperacute rejection occurs mainly at the endothelial cells in donor microvascular systems, but this does not occur at cardiac valve leaflets or at medium-to-large caliber vessels. On the basis of this background, this study was performed to look into the biocompatibility for transplantation of a middle or large diameter xenogenic blood vessel by conducting xenogenic arterial transplantation with the carotid artery in a pig-to-goat model. Material and Method: The experimental group was composed of 10 pairs of pig-to-goat combinations. They were divided into each period of 1 week, and 1, 3, 6 and 12 months. Four carotid artery grafts obtained through collection of the bilateral carotid arteries from two pigs were preserved at $-70^{\circ}C$ without other treatment, and then they were transplanted into the bilateral carotid arteries of two goats. Doppler ultrasonography was done on a periodic basis after transplantation to evaluate the patency of the grafted blood vessel. At the ends of a predetermined period, the grafts were explanted from the goats and they underwent gross examination. Hematoxylin-eosin and Masson's trichrome staining were conducted. In addition, in order to examine the immunological rejection of the grafted xenogenic blood vessel, immunohistochemical staining was conducted with T-lymphocyte indicator and von Willebrand factor. Result: Two goats at the each one-week period and the one-year period died during the experimental period because of a reason unrelated to the experimental procedure, and the remaining 8 goats survived until the end of each experiment period. On Doppler ultrasonography, unilateral carotid artery occlusion was found in a goat, whose period was specified as 3 months, among the 8 survived goats. However, the vascular patency was maintained well and there was no graft that formed aneurysms in the other goats. On gross examination, the region of vascular anastomosis was preserved well, and calcification of the grafted blood vessel was not shown. Histologically, the endothelial cells of the graft disappeared one week after transplantation, and then there was progressive spread of the recipients' endothelial cells from the anastomotic site. The reendothelialization occurred over the whole graft at one month after transplantation. The neointimal thickening and adventitial inflammation became severe by 3 months after transplantation, but this lessened at 6 months and 12 months, respectively. The rate of CD3 positive cells was very low among the infiltrated inflammatory cells. Conclusion: The fresh-frozen xenogenic artery kept its patency without being greatly influenced by xenogenic immune reaction.

• 대한예방의학회:학술대회논문집
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• 1999.10a
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• pp.150-151
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• 1999

• Korean Journal of Logic
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• v.10 no.1
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• pp.65-98
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• 2007

정인교는 그의 최근 논문에서 논리적 귀결 관계에 의해 논리 상항의 의미를 정의함에 있어 통상적인 도입 규칙과 제거 규칙에 의거하는 포퍼의 접근법과, 도입 규칙에만 의존하는 정당화주의적 접근법, 그리고 제거 규칙에만 의존하는 실용주의적 접근법을 구분한 바 있다. 이 글에서는 연언과 선언의 연결어의 경우에는 그 세 가지가 동등하다는 것을, 그리고 조건과 부정의 연결어의 경우에는 제거 규칙에 의거하는 실용주의적 접근법과 포퍼의 접근법이 대등하다는 것을, 타르스키가 처음 확립한 논리적 귀결에 관한 공리적 체계에 의존하여 보일 것이다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.44-46
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• 2000

본 논문은 Tertiary 저장장치를 이용한 대용량 비디오 서버의 설계와 구현에 대해서 기술한다. 서버는 서비스와 프로세스 관리 서브시스템, 자원 관리 서브시스템, 입출력 관리 서브시스템의 세 부분으로 구성된다. 입출력 대역폭이 낮은 Tertiary 저장장치의 효율적인 사용을 위해 디스크 캐쉬 풀 모델을 사용하고, 적절한 스케줄링 정책과 캐슁 알고리즘을 이용하여 가능한 많은 사용자를 수용한다. 서버는 Windows 2000에서 시스템 서비스로 구현되었으며 디스크 캐쉬의 효과적인 사용으로 Tertiary 저장장치의 낮은 대역폭을 최대한 활용하여 접속된 사용자에게 안정된 비디오 스트리밍 서비스를 제공한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.227-231
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• 2007

본 연구에서는 상거래 분야에서의 RFID를 이용한 비즈니스 모델과 함께 사업 참여자의 서비스 도입 가치를 탐색하였다. 제안하는 세 가지 비즈니스 모델은 RFID 서비스 인프라 환경을 고려하여 설계하였으며, 상거래 사업자에게는 기존에 수행하던 상거래 서비스의 효율화와 상거래 기능이 없었던 공간에서의 상거래 기능 부여, 모든 생활 공간의 상거래 가능 공간으로의 변화라는 가치를 제공한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.33-37
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• 1995

A side-cut grinding generates a machining error by the decrease of the quill rigidity. In this paper, The effect on the grinding force, machining error and surface roughness due to the change of the quill rigidity is investigated experimentally. The slenderness ratio of the quill is a significant factor to analyse the change of the grinding force and machining error.

• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.109-124
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• 1999

The major objective of this research is to design and build the variable structure DEVS modeling & simulation framework. To do this, we have proposed the direct message passing mechanism between the model and its simulator to deal with the structural demand from the model during the simulation. In this approach, four types of basic messages are introduced for the vertical(creation/deletion of the child) and horizontal(creation/deletion of the brother) structural changes. Proposed methodology has been successfully applied to the multi-processor system and the forest fire information system.

• Communications of Mathematical Education
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• v.18 no.1 s.18
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• pp.297-308
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• 2004

본 연구에서는 먼저, 수학교사에게 필요한 지식으로 교과, 학생, 교수학적 내용 지식이 필요함을 문헌을 통해 정리하였다. 교사의 지식과 수업 실제에 관한 세 편의 논문을 분석한 결과 교사의 수학에 대한 충분한 이해가 학생의 학습과 효과적인 교수에 절대적인 영향을 미친다고 주장할 수 없음을 알 수 있었다. 그러나 수학에 대한 바른 이해는 학생의 질문에 적절한 반응을 할 수 있도록 하며, 수업을 계획하고 교실에서 이루어지는 담화를 수학적으로 원활하게 조절할 수 있도록 도움을 줄 수도 있었다. 따라서 수학을 잘 아는 것이 효과적인 교수·학습을 보장하지는 못하지만, 교사가 잘 알지 못하는 것을 가르칠 수는 없다는 결론을 얻었다.