• 한국소음진동공학회논문집
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• 제13권10호
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• pp.821-827
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• 2003

The so-called boundary node method (or NDIF method) that was developed by the authors has been extended for free vibration analysis of arbitrarily shaped plates with free edges. Since the proposed method requires no interpolation functions. no integration Procedure is needed on boundary edges of the plates and only a small amount of numerical calculation is involved, compared with FEM and BEM. In order to explain tile reason why spurious eigenvalues are generated when the NDIF method is applied to free plates, the NDIF method has been considered for free vibration analysis of both a fixed string and a free beam. Finally, verification examples show that natural frequencies obtained by the present method agree well with those given by an exact method or a numerical method (ANSYS).

• 정보처리학회논문지C
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• 제11C권6호
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• pp.829-834
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• 2004

이동 에드 혹 네트워크(Mobile Ad hoc Network)에서는 노드들이 pear-to-pear 레벨에서 무선 채널을 통하여 대화 한다. 노드들은 지리적으로 이동이 자유로우며 무선 채널들은 영역 내에서 약하게 결합된다. 그리고 노드들이 자유롭게 이동할 수 있기 때문에 고정된 네트워크의 형태가 존재하지 않는다. 따라서 노드들간의 데이터 교관이나 노드간의 통신을 관리하기 위해서 리더 노드(Leader Node)가 필요하다. 본 논문에서는 이웃 노드간에만 대화가 허용되는 이동 에드 혹 네트워크를 위한 효율적인 리더 노드 선택 알고리즘을 소개한다. 그리고 시뮬레이션을 통한 알고리즘의 성능 평가 결과를 보인다. 본 논문에서 소개한 알고리즘은 노드들의 이동에 영향을 받지 않고 최소한의 무선 자원만을 사용하는 효율적이고 실용적인 알고리즘이다.

• 한국구조물진단유지관리공학회 논문집
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• 제8권4호
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• pp.107-114
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• 2004

본 논문에서는 복합적층판의 유한요소해석을 위해 직접수정법으로 간단히 개선된 8절점 유한요소를 제안하였다. 우선, 9절점 등매개변수 요소와 동일한 조건하에서 이차다항식을 표현할 수 있도록 형상함수를 수정하며, 이를 외시적(explicit)으로 표현하였다. 전단보정계수를 갖는 1차전단변형이론을 고차전단변형이론에 근거하여 간단히 개선함으로써 두께방향으로 전단응력 및 변형률이 포물선 분포를 가지도록 하였다. 더 이상의 전단보정계수가 필요하지 않다. 따라서 간단한 직접수정법 즉, 형상함수의 수정, 1차전단변형이론의 개선 및 가정변형률을 조합함으로써 8절점 유한요소의 성능을 개선하였다. 제안된 유한요소를 이용하여 복합적층판의 정적, 좌굴 및 자유진동 수치해석을 실시하여 비교 검증하였다.

• 전자공학회논문지B
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• 제30B권1호
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• pp.10-17
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• 1993

This paper analyzes succinct graph descriptions and its complexity of connectivity problems on context free graph languages under various restrictions. It defines SNLC(Simple Context Free Node Label Controlled) grammar and presents reduction method that solves graph problems without expanding the hierarchical description. It exemplifies the method by giving efficient solutions to connectivity problems on graphs and presents parallel algorithm for reduction and analyzes the complexity. Its results will help application of desing for NETWORK. CAD. VLSI and other engineering problems.

• Asian Pacific Journal of Cancer Prevention
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• 제16권2호
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• pp.519-522
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• 2015

Background: We aimed to investigate whether the tumor free distance (the distance between the uterine serosa and the tumor at its deepest point) is useful in surgical staging and in predicting prognosis. Materials and Methods: Data from patients who underwent complete surgical staging for endometrial cancer between January 2006 and June 2011 were reviewed retrospectively. All demographic findings, surgical stages, histological type and grade, myometrial invasion, lymphovascular space invasion as well as abdominal cytology, cervical, adnexal, and omental involvement, and lymph node metastasis were recorded. The relations between myometrial invasion and tumor free distance from uterine serosa with prognostic factors were investigated. Results: Seventy patients were included in the study. Sixty-four (91.5%) had endometrioid type cancers and forty-four (62.9%) were grade 1. The deepest myometrial invasion was less than 1/2 in 42 patients (60%). In 18 patients (25.8%) lymphovascular invasion was noted. Eight (11.4%) were found to have cervical involvement, five (7.1%) had adnexal involvement and in 4 cases (5.7%) the peritoneal washings included malignant cells. Four patients had pelvic and one para-aortic node metastasis. We recognized that an invasion of more than 1/2 was correlated significantly with lymphovascular space involvement, histological grade, positive abdominal washing cytology, nodal and cervical involvement, but not with adnexal involvement. Tumor-free myometrial thickness was negative and statistically significant correlated with surgical stage, histological grade, lymphovascular space involvement, positive abdominal washing cytology, cervical and adnexal involvement. The importance of tumor-free myometrial thickness in determinating the lymphovascular space invasion was found to be highest in terms of sensitivity and specificity when crossing the ROC curve at 11 millimeters. Conclusions: Depth of myometrial invasion is more valuable for predicting lymph node metastasis than tumor-free myometrial thickness. The tumor-free myometrial thickness provides a better prediction for adnexal involvement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권9호
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• pp.2285-2301
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• 2012

Peer-to-Peer (P2P) networks are becoming more and more popular in video content delivery services, such as Video on Demand (VoD). Scalability feature of P2P allows a higher number of simultaneous users at a given server load and bandwidth to use stream service. However, the quality of service (QoS) in these networks is difficult to be guaranteed because of the free-riding problem that nodes download the recourses while never uploading recourses, which degrades the performance of P2P VoD networks. In this paper, a distributed trust model is designed to reduce node's free-riding phenomenon in P2P VoD networks. In this model, the P2P network is abstracted to be a super node hierarchical structure to monitor the reputation of nodes. In order to calculate the reputation of nodes, the Hidden Markov Model (HMM) is introduced in this paper. Besides, a distinction algorithm is proposed to distinguish the free-riders and malicious nodes. The free-riders are the nodes which have a low frequency to free-ride. And the malicious nodes have a high frequency to free-ride. The distinction algorithm takes different measures to response to the request of these two kinds of free-riders. The simulation results demonstrate that this proposed trust model can improve QoS effectively in P2P VoD networks.

• 현장농수산연구지
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• 제23권1호
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• pp.27-30
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• 2021

일반적으로 구제역 백신 접종은 유침주사기를 사용하고 있다. 유침주사기 사용 시 근육 조직 및 림프구에 병변이 생기는 이상육이 발생하고 이는 소비자의 불만제기와 국내산 돼지고기(한돈)의 이미지 악화와 관련된다. 그 대안으로 무침주사기 개발이 이루어지고 있다. 본 연구는 무침주사기를 이용한 구제역 백신 접종 시 이상육 발생빈도를 조사하여 무침주사기의 활용성을 검증하기 위해 실시했다. 실험결과 무침주사기 사용 시 이상육의 발생이 유침주사기 사용 대비 유의적으로 낮았다(36 vs. 16%, p < 0.05). 따라서 무침주사기를 이용한 구제역 백신 접종 시 이상육 발생을 낮춰 돈육 품질을 높이고 소비자 불만을 감소시킬 수 있을 것으로 판단된다. 추가 연구로 무침주사기의 항체형성률, 작업효율성, 경제적 비용 등을 조사하고 무침주사기의 활용성을 검증할 필요가 있다.

• 한국지능시스템학회논문지
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• 제8권4호
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• pp.1-7
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• 1998

This paper describes a meshless of element-free method based on fuzzy knowledge processing. To efficiently simulate complicated physical phenomena with dynmics and non-linear ploblem using computational mechanics, special method is required such as parallel processing or adaptive analysis techniques. However, the conventional finite element method is too complicated to be employed in the above cases. In order to reduce the above complexity of the conventional finite element analysis systms, the so called meshles finite elements as an input information have been stuided. Node is generated if its distance form existing node points is similar to the node spacing fuction at the point. The node spacing function is well controlled by the fuzzy knowledge processing Practical performances of the present system are demonstrated through several three-dimensional(3D) problems.

• 국제초고층학회논문집
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• 제1권1호
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• pp.29-36
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• 2012

The diagrid structural system is considered to be not only the best structural system for constructing free form structures, but also a very effective system in resisting lateral load. As a newly investigated structural system, its complicated node has not yet been completely investigated and minimal experimentation of manufacturing and constructing the system have been conducted. Therefore, the constructing cost of the diagrid structural system is still comparatively high. In this paper, the cyclic performance of a diagrid node with an H-section brace will be discussed. Design details that consider productivity were proposed and their structural performances were assessed through experimental and analytical investigation.

• Structural Engineering and Mechanics
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• 제13권4호
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• pp.387-410
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• 2002

Formulation of an 8 nodes assumed strain shell element is presented for the analysis of shells. The stiffness matrix based on the Mindlin-Reissner theory is analytically integrated through the thickness. The element is free of membrane and shear locking behavior by using the assumed strain method such that the element performs very well in modeling of thin shell structures. The material is assumed to be isotropic and laminated composite. The element has six degrees of freedom per node and can model the stiffened plates and shells. A great number of numerical testing carried out for the validation of present 8 node shell element are in good agreement with references.