Precision shape modeling by z-map model

Park, Jung-Whan,Chung, Yun-Chan,Choi, Byoung-Kyn Korean Society for Precision Engineering 2002 International Journal of the Korean Society of Pre Vol.3 No.1

The Z-map is a special farm of discrete non-parametric representation in which the height values at grid points on the xy-plane are stored as a 2D array z[ij]. While the z-map is the simplest farm of representing sculptured surfaces and is the most versatile scheme for modeling non-parametric objects, its practical application in industry (eg, tool-path generation) has aroused much controversy over its weaknesses, namely its inaccuracy, singularity (eg, vertical wall), and some excessive storage needs. Much research or the application of the z-map can be found in various articles, however, research on the systematic analysis of sculptured surface shape representation via the z-map model is rather rare. Presented in this paper are the following: shape modeling power of the simple z-map model, exact (within tolerance) z-map representation of sculptured surfaces which have some feature-shapes such as vertical-walls and real sharp-edges by adopting some complementary z-map models, and some application examples.

Z-map으로 표현된 수직 벽면을 가진 금형에서의 접촉처리법과 클로버형 컵 디프드로잉 공정의 해석에의 응용

서의권,박정환,심현보 한국공작기계학회 1998 한국생산제조학회지 Vol.7 No.5

The Z-map model which is quite similar to the non-parametric patch is widely used to describe the shape of a surface because of its simplicity. Despite the inherent advantage of z-map model, it has drawbacks that there exists difficulty in expressing the vertical walls and its related contact treatment method. In the region of vertical walls, there is a convergence problem in searching the contact point. In this study a contact point finding scheme is presented, based on the z value of vertical-wall-included clover shape cup deep drawing process is analyzed and the results are compared with the experimental results. The effects of the Z-map grid distances and the interpolations of the inside Z-map value are also discussed.

Z-map으로 표현된 금형에서의 접촉처리법과 L형 컵 디프드로잉 공정 해석에의 응용

金正顯,徐義權 慶一大學校 1999 論文集 Vol.16 No.3

, The z-map model which is quite similar to a non-parametric patch is widely used in describing the shapes of surfaces because of its simplicity. Despite its inherent advantage, z-map model has drawbacks such as difficulties in expressing the vertical walls and its related contact treatment method. Especially In the vertical walls, there exists a convergence problem in searching a contact point. In this study a contact point finding scheme based on sheet normal scheme in the z-map model is presented. To show the utility of this scheme, L shape cup deep drawing, which include vertical walls processes are analyzed. The results are compared with the experimental results and the results of commercial FE code PAM-STAMP whose results are widely accepted.

Z-map과 모폴로지 필터를 이용한 문화재 문자 복원

문호석(Ho Seok Moon),손명호(Myung Ho Sohn) 한국컴퓨터정보학회 2006 한국컴퓨터정보학회지 Vol.14 No.2

본 논문에서는 글자가 새겨져 있는 마모된 문화재의 글자를 Z-map과 영상처리를 이용해 복원하는 새로운 알고리즘을 제시한다. 문화재에 새겨져 있는 글자는 많은 탁본을 통해서 또는 세월이 흐름에 따라 마모되어 최초의 상태와 다른데, 마모된 부분을 찾고 보강하는 작업이 필요하다. 이 작업을 수동으로 하게 되면 여러 가지 문제점이 발생하게 되는데, 자동으로 복원하는 방법이 필요하다. 본 논문에서는 이러한 글자 복원에 대한 구현 가능한 알고리즘을 제안하였다. 팔만대장경을 대상으로 하였고, Z-map과 모폴로지 필터가 이 과정에 사용되었다. In this paper. we propose a new algorithm for recovering the broken letters of relics into an original form by using Z-map and image processing. The letters of relics may have been broken by a lot of rubbed copy and a long time and tide. They need to be restored. But the manual reconstruction is a very tedious and laborious task. Thus. it is necessary to automate the restoration process. This paper presents a realistic algorithm with an application to Tripitaka Koreana by using Z-map and morphological filter.

Z-map 기반 가공 검증모델을 이용한 칩부하 제어기

백대균(Dae Kyun Baek),고태조(Tae Jo Ko),박정환(Jung Whan Park),김희술(Hee Soo1 Kim) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.4

This paper presents a new method for the optimization of feed rate in sculptured surface machining. A NC verification model based on Z-map was utilized to obtain chip load according to feed per tooth. This optimization method can regenerate a new NC program with respect to the commanded cutting conditions and the NC program that was generated from CAM system. The regenerated NC program has not only the same data of the ex-NC program but also the updated feed rate in every block. The new NC data can reduce the cutting time and produce precision products with almost even chip load to the feed per tooth. This method can also reduce tool chipping and make constant tool wear.

Z세대의 뉴스 소비 행태 분석 연구 - 서비스 디자인 방법론을 활용하여

임정민(Jeong-Min Lim),전우정(Woo-Jeong Chon) 한국디지털콘텐츠학회 2021 한국디지털콘텐츠학회논문지 Vol.22 No.12

Recently, news has undergone changes in various media due to the development of information and communication technologies such as the Internet and mobile, and news consumption behavior is also changing accordingly. Unlike other generations, changes in news consumption behavior according to these changes in news media are more pronounced to Generation Z with a growth background grown using digital media. Therefore, this study analyzed the news consumption behavior of Generation Z in depth through service design methodology and process. As complaints, the authors identified news content that reduced credibility, the inconvenience of newsletter delivery, and interactions that prevented focus on the news. As requirements, a fun factor through the method of news branding, in-depth news content, and positive interaction between news users was derived.

전극의 3차원 측정데이터로부터 방전가공조건 결정

주상윤,이건범 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.5

This paper proposes a method for determining optimal EDM parameters based on discharge area from the physical model of a tool electrode. Main parameters, which affect the EDM performance, are peak value of currents, pulse-on time, and pulse-off time. Such parameters are closely dependent on the discharge area in EDM process. In this paper the dis-charge area is estimated from the CMM scanning data to the tool electrode. The method is very useful when any geomet-ric information to the tool electrode is not provided from tool modeler or producer. The method consists of following four steps. First a triangulation mesh is constructed from the CMM data. Secondly, the z-map is modeled from the triangulated mesh. Thirdly, the discharge area is estimated from intersection between the z-map model and a z-height plane. Finally, the machining parameters are easily calculated by some known EDM equations to the discharge area. An example is intro-duced to show that the machining parameters are calculated from the CMM data to a tool electrode.

제품 설계 데이터를 이용한 프레스 금형 레이아웃 설정을 위한 알고리즘에 관한 연구

이상준,이성수 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.6

Today most companies are designing their automobile shapes by using 3 dimensional CAD software, CATIA. And they used to design 2 dimensional press dies to do some elastic work on their products, but they are currently trying to make use of 3 dimensional software, Pro-Engineer. In this case, they have to change the 3 dimensional product design data to the proper format data for the following process. This paper will show the data loss and the deformation during data transfer between CATIA and Pro-Engineer, and then suggest a solution for these problems. Product's surface will be automatically placed by automatic press tipping angle setting in CATIA to prevent the product from being stuck in the press die. The 2 dimensional section view which is based on the tipping angle setting is created by Z-map. And, to remove the data loss and the data deformation in Pro-Engineer, the product surface are delivered to the next process after it is changed to the 2 dimensional Z-map curves in CATIA. Finally, this paper suggests an algorithm to develop the automatic design program for the press layout which regenerates product shape surface from the previous process.

3차원 스캐닝 기술을 통한 문화재 형태 융합기술 연구 -안성기솔리 석불입상과 관련하여-

최원호,정성권 한국지식정보기술학회 2013 한국지식정보기술학회 논문지 Vol.8 No.3

This paper studies about cultural assets image which was made by 3D scanning. In this paper, we shows that how 3D scanning works and we also explain that what is the Z-map and how to make the digital rubbed copy. By those several technique, we can get the Z-map and digital rubbed copy of the Ansung Gisolri Stone Buddha image. These images help to reveal that when the Buddha image was made. Until now, most of art historians use the rubbed copy to get specific image of stone arts. The fusion technique for cultural assets image by 3D scanning will help art scholars by giving them clear image of cultural assets.

A Borsuk--Ulam type theorem over iterated suspensions of real projective spaces

Ryuichi Tanaka 대한수학회 2012 대한수학회지 Vol.49 No.2

A CW complex B is said to be I-trivial if there does not exist a Z2-map from Si-1 to S() for any vector bundle over B and any integer i with i > dim . In this paper, we consider the question of determining whether kRPn is I-trivial or not, and to this question we give complete answers when k ̸= 1, 3, 8 and partial answers when k = 1, 3, 8. A CW complex B is I-trivial if it is "W-trivial", that is, if for every vector bundle over B, all the Stiefel{Whitney classes vanish. We nd, as a result, that kRPn is a counterexample to the converse of this statement when k = 2, 4 or 8 and n ≥ 2k.