2D wavelet transform data compression with error level guarantee for Z-map models

Nobuyuki Umezu,Keisuke Yokota,Masatomo Inui 한국CDE학회 2017 Journal of computational design and engineering Vol.4 No.3

Most of workpiece shapes in NC milling simulations are in Z-map representations that require a very large amount of data to precisely hold a high resolution model. An irreversible compression algorithm for Z-map models using a two-dimensional Haar wavelet transform is proposed to resolve this tight memory situation for an ordinary PC. A shape model is first transformed by using Haar wavelet to build a wavelet synopsis tree while the maximum errors caused by virtually truncating high-frequency components are simultaneously calculated. The total amount of the shape data can be reduced by truncating particular sections of the wavelet components that satisfy the error threshold given by the user. Our algorithm guarantees that any error due to its irreversible compression processes is smaller than the specified level measured against the original model. A series of experiments were conducted using an Apple iMac with a 3.2 GHz CPU and 8 GB of memory. The experiments were performed with 16 sample shape models on 512?512 to 8192?8192 grids to evaluate the compression efficiency of the proposed method. Experimental results confirmed that our compression algorithm requires approximately 20–30 ms for 512?512 models and 7 s for 8192?8192 models under a maximum error level of 10? 10?6 m (a typical criteria for NC milling simulations). The compressed binaries outputted by the proposed method are generally 25–35% smaller than the baseline results by gzip, one of common reversible compression libraries, while these two methods require almost the same level of computational costs.

교육 실천 성찰력을 기르기 위한 교원양성 코어 커리큘럼의 구상과 전개 -나루토(鳴門) 교육대학의 교원양성 교육개혁-

우메즈 마사미 공주교육대학교 초등교육연구소 2007 초등학교교육연구 = Elementary school education research Vol.7 No.1

본 논문의 목적은 일본 나루토 교육대학 프로그램으로서 2005년도부터 추진하고 있는 '교육 실천 성찰력을 기르기 위한 교원양성 코어 커리큘럼'의 논리와 실천을 소개함으 로써, 교원양성 교육 개혁의 이론적•실천적 방향성을 제시하는 것이다. 동 프로그램의 주요 줄거리는 다음 세 가지이다. 즉, ①수업실천력을 평가하는 객관 적 척도가 되는 수업실천력 평가 스탠더드를 개발하는 것, ②수업실천력 평가 스탠더드 를 틀로 하여, '교육 실천학을 중핵으로 하는 교사양성 코어 커리큘럼(나루토 플랜)을 실천하고 평가하는 것, ③수업실천력 평가 스탠더드와 '지(知)의 종합화 노트' 및 수업실 천 영상 데이터베이스를 조합하여, 학생이 자신의 실천력을 진단하고, 직능(職能)개발의 도달도와 과제를 명확히 할 수 있는 시스템을 구축하는 것이다. The purpose of this article is to show theoretical and practical directionality for reform of teacher training education through introducing the logic and practice of teacher training core curriculum for cultivating ability for reflection on educational practice which Naruto University of Education(NUE) elaborates a plan as University Project. The ability for reflection on educational practice is ability that a teacher evaluate own educational practice, and can improve it. The basic design of teacher training educational reform of NUE for cultivating ability for reflection on educational practice consists of three contents. The first content is to develop standard to evaluate practical teaching skills of subject education. The second is to practice teacher training core curriculum with standard as a frame, and evaluate it. The third is to build a system that a student diagnoses own educational practice ability, and can improve it through putting standard and the Note for Integration of Intellect and the Class Practice Picture Database. The author thinks that the reform plan of NUE can apply widely to not only teacher training education but also higher education reform.

Optimal Porous Structure of MnO₂/C Composites for Supercapacitors

Iwamura, Shinichiroh,Umezu, Ryotaro,Onishi, Kenta,Mukai, Shin R. Materials Research Society of Korea 2021 한국재료학회지 Vol.31 No.3

MnO2 can be potentially utilized as an electrode material for redox capacitors. The deposition of MnO2 with poor electrical conductivity onto porous carbons supplies them with additional conductive paths; as a result, the capacitance of the electrical double layer formed on the porous carbon surface can be utilized together with the redox capacitance of MnO2. However, the obtained composites are not generally suitable for industrial production because they require the use of expensive porous carbons and/or inefficient fabrication methods. Thus, to develop an effective preparation procedure of the composite, a suitable structure of porous carbons must be determined. In this study, MnO2/C composites have been prepared from activated carbon gels with various pore sizes, and their electrical properties are investigated via cyclic voltammetry. In particular, mesoporous carbons with a pore size of around 20 nm form a composite with a relatively low capacitance (98 F/g-composite) and poor rate performance despite the moderate redox capacitance obtained for MnO2 (313 F/g-MnO2). On the other hand, using macro-porous carbons with a pore size of around 60 nm increases the MnO2 redox capacitance (399 F/g-MnO2) as well as the capacitance and rate performance of the entire material (203 F/g-composite). The obtained results can be used in the industrial manufacturing of MnO2/C composites for supercapacitor electrodes from the commercially available porous carbons.

Automatic detection of the optimal ejecting direction based on a discrete Gauss map

Inui, Masatomo,Kamei, Hidekazu,Umezu, Nobuyuki Society for Computational Design and Engineering 2014 Journal of computational design and engineering Vol.1 No.1

In this paper, the authors propose a system for assisting mold designers of plastic parts. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with minimum undercuts. Since plastic parts are generally very thin, many rib features are placed on the inner side of the part to give sufficient structural strength. Our system extracts the rib features from the CAD model of the part, and determines the possible ejecting directions based on the geometric properties of the features. The system then selects the optimal direction with minimum undercuts. Possible ejecting directions are represented as discrete points on a Gauss map. Our new point distribution method for the Gauss map is based on the concept of the architectural geodesic dome. A hierarchical structure is also introduced in the point distribution, with a higher level "rough" Gauss map with rather sparse point distribution and another lower level "fine" Gauss map with much denser point distribution. A system is implemented and computational experiments are performed. Our system requires less than 10 seconds to determine the optimal ejecting direction of a CAD model with more than 1 million polygons.

Automatic Detection of the Optimal Ejecting Direction Based on a Discrete Gauss Map

Masatomo Inui,Nobuyuki Umezu,Hidekazu Kamei (사)한국CDE학회 2013 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8

In this paper, the authors propose a system for assisting mold designers of plastic parts. Plastic parts are usually produced by the injection molding. In this method, the formed part must be removed from the mold core in a single ejecting direction. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with the minimum undercuts. Two methods are introduced for improving the performance and the accuracy of the authors’ prior system. New point distribution method for the discrete Gauss map is adopted which is based on the architectural geodesic dome concept. Hierarchical structure is also introduced in the point distribution, a higher level “rough” Gauss map with sparse point distribution and another lower level “fine” Gauss map with much dense point distribution. By using this discrete Gauss map representation, a new algorithm is developed for computing the optimal ejecting direction. An experimental system is implemented and computational experiments are performed. Our system needs less than 30 seconds for determining the optimal ejecting direction of a CAD model with more than 1 million polygons.

An Optimization Study of Hot Stamping Operation

Bonyoung Ghoo,Yasuyoshi Umezu,Yuko Watanabe,Ninshu Ma,Ron Averill 한국소성가공학회 2010 기타자료 Vol.2010 No.6

In the present study, 3-dimensional finite element analyses for hot-stamping processes of Audi B-pillar product are conducted using JSTAMP/NV and HEEDS. Special attention is paid to the optimization of simulation technology coupling with thermal-mechanical formulations. Numerical simulation based on FEM technology and optimization design using the hybrid adaptive SHERPA algorithm are applied to hot stamping operation to improve productivity. The robustness of the SHERPA algorithm is found through the results of the benchmark example. The SHERPA algorithm is shown to be far superior to the GA (Genetic Algorithm) in terms of efficiency, whose calculation time is about 7 times faster than that of the GA. The SHERPA algorithm could show high performance in a large scale problem having complicated design space and long calculation time.

학생의 사회 인식 발달의 변용에 관한 조사적 연구 -중학교 역사 학습의 경우-

가토토시아키 ( Kato Toshiaki ),우메즈마사미 ( Umezu Masami ),마에다켄이치 ( Maeda Kenichi ),니미나오 ( Niimi Naoko ) 역사교육학회 2014 역사교육논집 Vol.52 No.-

The purpose of this study is to conduct a developmental research on junior high school students` social thinking abilities and judgmental abilities. Specifically, this study focused on the following two. First, we clarified the developmental changes in students` social cognition: social thinking abilities and judgmental abilities. Second, the relationships among the five predicted components of the social thinking skills and judgmental skills as a part of social science skill were examined. The five predicted components were factual judgment ability, inductive reasoning ability, deductive reasoning ability, social judgment ability, and critical thinking ability. The results showed that the students` inductive reasoning ability, deductive reasoning ability, social judgment ability, and critical thinking ability were positively related with their grade levels, and this tendency was especially prominent in their transition from the second to the third grades. Also, the sequential order in degree of difficulties (e.g. from inductive and deductive reasoning abilities to social judgment ability, followed by critical thinking ability) and the interrelationship among these five abilities were revealed.

A Dexel Based Algorithm for Evaluating Thickness of Solid Models (ACDDE 2010)

Satoru Yamazaki,Nobuyuki Umezu,Mastomo Inui (사)한국CDE학회 2010 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8

In the current manufacturing practice, injection molding is widely used for fabricating plastic parts of various consumer products such as digital cameras, printers, and other electric appliances. In designing a plastic part, thickness of the part should be constant all over the surface, otherwise some deformations happen in the molding process which deteriorate the aesthetic quality of the product. In this paper, the authors propose a fast algorithm for evaluating the thickness of the solid model. Most commercial CAD systems provide some kinds of thickness measuring functions of solid models, these functions, however, are not appropriate for evaluating thickness of the complex shape. In this paper, a new definition of the thickness of the solid model is proposed. Based on the definition, a dexel based thickness evaluation algorithm is developed. A depth peeling based method for converting a boundary representation solid model into a solid model in the dexel representation is also proposed. A system is implemented and some computational experiments are performed.

Visualization of potential sink marks using thickness analysis of finely tessellated solid model

Masatomo Inui,Shunsuke Onishi,Nobuyuki Umezu 한국CDE학회 2018 Journal of computational design and engineering Vol.5 No.4

Sink marks are unwanted shallow depressions on the molded plastic surface caused by localized shrink-age during the hardening process of injection molding. Sink marks appearing in the exterior impair the aesthetic quality of the product. In this study, a novel method for extracting potential sink marks that can occur on the part surface is proposed. The thicker portion of the part shrinks with a greater amount than that of the thinner portion. This difference in the shrinkage amount is the main cause of the sink mark. In the plastic part design practice, engineers often check the thickness distribution to predict potential sink marks in the part surface. Our method can be considered as an automated technique of such manual inspection task. A polyhedral solid model of the part with sufficiently small triangles of nearly the same size is prepared. The amount of shrinkage at each polygon is estimated based on its thickness and the shrinkage ratio of the part. The developed algorithm extracts the potential sink marks by analyzing the shrinkage distribution on the part surface.

Impact of TAGS Measurement on FP Decay Data and Decay Heat Calculations

T. Yoshida,N. Hagura,R. Umezu,A. Algora,J. L. Tain,D. Jordan,T. Tachibana 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

Nuclear level schemes are usually constructed from the high-resolution data of the gamma-ray transitions which immediately follow the beta-decay of their parents. It is recognized that this procedure may lead to the ``\textit{pandemonium} problem.'' If we use the decay data suffering from the pandemonium problem for the decay heat calculations the beta-ray component will be overestimated and the gamma-ray component underestimated. The beta-feeding data obtained by the total absorption gamma-ray spectroscopy (TAGS) is proved to be free from this problem. In the case of the Japanese data base for the FP decay heat calculation, the theoretical values based on the gross theory of beta-decay are widely introduced to circumvent the pandemonium problem. The gross theory, however, is not good at describing any beta-transition exclusively concentrating to a single level in the daughter nucleus. The TAGS method is also proved to be able to save this situation. Further, we have to change our comprehension over the currently published decay schemes.