Web Structure Mining by Extracting Hyperlinks from Web Documents and Access Logs

It is difficult to predict Web structures for being rapidly changed with frequent updates of documents on the Web. Nevertheless,given the structures, information providers can discover users'behavior patterns and characteristics and supply better services to users, and users can find useful information easily and exactly. This paper proposes an improved method for extracting Web structures. The method consists of two steps. The first is constructing a directed graph on Web documents as node with their hyperlinks using the depth-first search algorithm. The second is making up for the direct graph by discovering the hyperlinks, which are not extracted in the first step, called hidden hyperlinks. They can be found by analyzing Web access logs, in which click streams are contained. The click streams do not include clicks on 'Back' buttons because of the local cache problem of Web browsers. This causes the problem not finding correct hidden hyperlinks. To cope with the problems, this paper propose an algorithm on searching hidden hyperlinks. We have simulated the discovery of the hidden hyperlinks to evaluate the proposed method experimentally. Through the simulations, we have observed that the proposed method discovers most hidden hyperlinks appeared on clickstreams. In the future we should develop some tools for visualizing discovered Web structures and do study on discovering more correct hidden hyperlinks through improving the proposed algorithm.제 1 장 서론 = 1 제 2 장 관련 연구 = 4 21 웹 마이닝 = 4 22 웹 로그 = 6 23 웹 로그 전처리 과정 = 10 24 클릭스트림 = 14 제 3 장 웹 문서 구조화 = 15 31 웹 문서의 하이퍼링크 구조화 = 16 32 접근로그 전처리 과정 = 23 33 클릭스트림 수집 = 25 34 접근로그를 통한 정점과 간선 추가 = 28 제 4 장 시스템 구현 및 실험 = 37 41 시스템 구현환경 = 37 42 시뮬레이션 = 42 제 5 장 결론 및 향후 과제 = 51 참고문헌 = 5

제28회 충청중국포럼(CNI세미나2018-007)(박철현)

◈ '충청중국포럼'은 2015년 5월 출범 이후 충남도와 시, 군 중국교류 관련업무 담당자의 주도적 학습을 통한 역량 강화와 교류의 장으로 개최, 운영되어 왔음 ◈ 이번 제28회 충청중국포럼은 국민대학교 박철현 교수를 초청해 '두 중국 도시 이야기: 상해와 심양'을 주제로 발표와 토론을 진행하고자 함.❍ 주 제 : 두 중국 도시 이야기: 상해와 심양 ❍ 일 시 : 2018. 02. 28.(수) 10:00~12:00 ❍ 장 소 : 충남연구원 4층 회의실 ❍ 연 사 : 박철현 교수(국민대학교) ❍ 참 석 : 충청남도 및 각 시군 중국교류업무 담당자 및 관심있는 모든

Preform Design Technique by Tracing The Material Deformation Behavior

Preform design techniques have been investigated in efforts to reduce die wear and forming load and to improve material flow, filing ratio, etc. In hot forging processes, a thin deformed part of a workpiece, known as a flash, is formed in the narrow gap between the upper and lower tools. Although designers make tools that generate a flash intentionally in order to improve flow properties, excessive flash increases die wear and forming load. Therefore, it is necessary to make a preform shape that can reduce the excessive flash without changing flow properties. In this paper, a new preform design technique is proposed to reduce the excessive flash in a metal forging process. After a finite element simulation of the process is carried out with an initial billet, the flow of material in the flash region is traced from the final shape to the initial billet. The region belonging to the flash is then easily found in the initial billet. The finite element simulation is then carried out again with the modified billet from which the selected region has been removed. In several iterations of this technique, the optimal preform shape that minimizes the amount of flash without changing the forgeability can be obtained

Adaptive Delaunay Mesh Generation Technique Based on a Posteriori Error Estimation and a Node Density Map

In this study, a remeshing algorithm adapted to the mesh density map using the Delaunay mesh generation method is developed. In the finite element simulation of forging process, the numerical error increases as the process goes on because of discrete property of the finite elements and distortion of elements. Especially, in the region where stresses and strains are concentrated, the numerical error will be highly increased. However, it is not desirable to use a uniformly fine mesh in the whole domain. Therefore, it is necessary to reduce the analysis error by constructing locally refined mesh at the region where the error is concentrated such as at the die corner. In this paper, the point insertion algorithm is used and the mesh size is controlled by using a mesh density map constructed with a posteriori error estimation. An optimized smoothing technique is adopted to have smooth distribution of the mesh and improve the mesh element quality

Visualization of finite element analysis for forging processes by using object-oriented programming technique

학위논문(석사) - 한국과학기술원 : 기계공학과, 1998.2, [ iv, 61 p. ]한국과학기술원 : 기계공학과

Design of Preform using equi-potential lines in Hot Forging

The equi-potential lines designed in the electric field are introduced to find the preform shape in axisymmetric hot forging. The equi-potential lines generated between two conductors of different voltages show similar trends of the minimum work paths between the undeformed shape and the deformed shape. Base on this similarity the equi-potential lines obtained by arrangement of the initial and final shapes are utilized for the design of preform and then the artificial neural network is used to find the range of initial volume and potential value of the electric field

Optimal Design of Preform in Hot forging

The equi-potential lines designed in the electric field are introduced to find the preform shape in axisymmetric hot forging. The equi-potential lines generated between two conductors of different voltages show similar trends of the minimum work paths between the undeformed shape and the deformed shape. Base on this similarity, the equi-potential lines obtained by arrangement of the initial and final shapes are utilized fur the design of preform, and then the artificial neural network is used to find the range of initial volume and potential value of the electric field