• 제목/요약/키워드: Tolerance Feature

검색결과 72건 처리시간 0.029초

일본의 '다문화공생' 정책을 사례로 본 사회통합정책의 과제 (The Problems of the Social Integration Policy - A Case Study of Social Tolerance Policy in Japan -)

  • 조현미
    • 한국지역지리학회지
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    • 제15권4호
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    • pp.449-463
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    • 2009
  • 일본의 다문화공생정책의 특징은 중앙정부가 지방정부의 역할의 중요성을 강조하고, 지방정부가 주체가 되어 다문화공생 정책을 추진해나갈 수 있도록 제도적 틀을 제시한다는 점에 있다. 즉, 일본의 다문화공생 정책은 실제로 정책이 실시되고 있는 지역의 다양성을 반영하기 위한 아래로부터 위로의 의견의 전달, 중앙정부 차원에서의 위로부터 아래로의 정책방향의 제시 및 권고를 통하여 다문화정책의 한계점을 극복하고자 하고 있다. 다문화공동체내의 시민단체, 연구자, 다문화가정 등과 같은 각 집단을 연결해주는 네트워크의 중심자의 역할에 따라 각 집단이 수행하는 기능의 활성화와 효율성은 달라진다. 그러므로 다문화현상이 실제로 진행되고 있는 지역에서 지방정부가 조정과 통합의 역할을 수행함으로서 중심 자로서의 역할을 담당하도록 하고 있다는 점에서 일본의 다문화공생정책은 사회통합적인 다문화정책의 방향을 본격적으로 모색하기 시작한 한국의 다문화정책에 많은 시사점을 제공한다.

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정밀제조를 위한 기하공차에서의 윤곽공차 사용 (A Profile Tolerance Usage in GD&T for Precision Manufacturing)

  • 김경욱;장성호
    • 산업경영시스템학회지
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    • 제40권2호
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    • pp.145-149
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    • 2017
  • One of the challenges facing precision manufacturers is the increasing feature complexity of tight tolerance parts. All engineering drawings must account for the size, form, orientation, and location of all features to ensure manufacturability, measurability, and design intent. Geometric controls per ASME Y14.5 are typically applied to specify dimensional tolerances on engineering drawings and define size, form, orientation, and location of features. Many engineering drawings lack the necessary geometric dimensioning and tolerancing to allow for timely and accurate inspection and verification. Plus-minus tolerancing is typically ambiguous and requires extra time by engineering, programming, machining, and inspection functions to debate and agree on a single conclusion. Complex geometry can result in long inspection and verification times and put even the most sophisticated measurement equipment and processes to the test. In addition, design, manufacturing and quality engineers are often frustrated by communication errors over these features. However, an approach called profile tolerancing offers optimal definition of design intent by explicitly defining uniform boundaries around the physical geometry. It is an efficient and effective method for measurement and quality control. There are several advantages for product designers who use position and profile tolerancing instead of linear dimensioning. When design intent is conveyed unambiguously, manufacturers don't have to field multiple question from suppliers as they design and build a process for manufacturing and inspection. Profile tolerancing, when it is applied correctly, provides manufacturing and inspection functions with unambiguously defined tolerancing. Those data are manufacturable and measurable. Customers can see cost and lead time reductions with parts that consistently meet the design intent. Components can function properly-eliminating costly rework, redesign, and missed market opportunities. However a supplier that is poised to embrace profile tolerancing will no doubt run into resistance from those who would prefer the way things have always been done. It is not just internal naysayers, but also suppliers that might fight the change. In addition, the investment for suppliers can be steep in terms of training, equipment, and software.

시퀀스 데이터베이스를 위한 서브시퀀스 탐색 : 세그먼트 기반 접근 방안 (Efficient Subsequence Searching in Sequence Databases : A Segment-based Approach)

  • 박상현;김상욱;노웅기
    • 한국정보과학회논문지:데이타베이스
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    • 제28권3호
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    • pp.344-356
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    • 2001
  • 본 논문에서는 시퀀스 데이터베이스에서 시간왜곡 변환(time warping)을 지원하는 서브시퀀스 탐색 문제를 다룬다. 서브시퀀스 탐색은 데이터 시퀀스의 평균 길이의 이차 함수로 성능이 저하된다. 이러한 문제를 해결하기 위하여 본 논문에서는 세그먼트 기반 서브시퀀스 탐색 기법(Segment-Based Approach for Subsequence Searches : SBASS)을 제안한다. SBASS는 데이터와 질의 시퀀스를 연속된 세그먼트들로 분할하여 다음의 두가지 조건을 만족하는 모든 데이터 시퀀스를 검색한다. (1) 세그먼트의 개수가 질의 시퀀스의 세그먼트 개수와 같다. (2) 모든 세그먼트 쌍 간의 거리가 주어진 오차 한도 이내이다. 제안된 세그먼트 분할 기법에서는 세그먼트가 서로 다른 길이를 갖도록 허용하며, 세그먼트 쌀간의 유사성의 척도로서 시간왜곡 변환 거리를 이용한다. 효율적인 유사 서브시퀀스 탐색을 위하여, 각 데이터 세그먼트로부터 요서 값들이 단조적으로 변화하는 특성을 이용하여 특성 벡터를 추출하고, 추출된 특성 벡터를 이용하여 공간 인덱스를 생성한다. 질의는 이 인덱스를 이용하여 (1) R-트리 여과, (2) 특성 여과, (3) 순서 여과, (4) 후처리의 네 단계로 처리된다. 다양한 실험을 통하여 제안된 기법의 효율성을 입증한다.

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Parallel Generation of NC Tool Paths for Subdivision Surfaces

  • Dai Junfu;Wang Huawei;Qin Kaihuai
    • International Journal of CAD/CAM
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    • 제4권1호
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    • pp.47-53
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    • 2004
  • The subdivision surface is the limit of recursively refined polyhedral mesh. It is quite intuitive that the multi-resolution feature can be utilized to simplify generation of NC (Numerical Control) tool paths for rough machining. In this paper, a new method of parallel NC tool path generation for subdivision surfaces is presented. The basic idea of the method includes two steps: first, extending G-Buffer to a strip buffer (called S-Buffer) by dividing the working area into strips to generate NC tool paths for objects of large size; second, generating NC tool paths by parallel implementation of S-Buffer based on MPI (Message Passing Interface). Moreover, the recursion depth of the surface can be estimated for a user-specified error tolerance, so we substitute the polyhedral mesh for the limit surface during rough machining. Furthermore, we exploit the locality of S-Buffer and develop a dynamic division and load-balanced strategy to effectively parallelize S-Buffer.

Anatomy and Morphology of Two Hawaiian Endemic Portulaca Species

  • Kim, InSun
    • Applied Microscopy
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    • 제44권2호
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    • pp.41-46
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    • 2014
  • In this study, the vegetative and reproductive morphology and anatomy of two Hawaiian endemic Portulaca species were examined. Specifically, P. molokiniensis and P. sclerocarpa were compared to closely related species in the genus. The comparisons were both qualitative and quantitative, using characteristics of leaves, stems, roots, and fruits. Tissue organizations of vegetative and reproductive parts of the plants were assessed using microtechnique procedures, statistical analysis, and scanning electron microscopy. The most notable features of these two species were (1) the size and frequency of stomata in P. molokiniensis, and (2) the large number of sclerenchymatous cell layers in the thickest fruit walls of P. sclerocarpa. These findings may imply that stomata development in P. molokiniensis and thick fruit wall development in P. sclerocarpa are evolved features of survival. In particular, the development of thickened walls in indehiscent fruits likely has evolutionary implications of ecological tolerance for better adaptation.

자동차용 축대칭 형상 부품 외경 자동측정시스템에 관한 연구 (A Study on Automated Outer Diameter Measurement System for Axisymmetric Automotive Part)

  • 반갑수;배준영
    • 한국기계가공학회지
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    • 제12권3호
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    • pp.61-68
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    • 2013
  • Automatic measurement system is required since cycle time and cost of production are increased by various factors in manual systems. This paper presents a machine vision based prototype measurement system for the automotive axisymmetric shape parts which are generally measured by a manual system that is required the tolerance of the part is very small on each machined surface. This measurement system adopts a method in which optical lens is transferred along the profile of the part to minimize measurement cycle time. The main interest of this paper is a development of an optimum measurement algorithm to the outside diameter of the parts that can be applied to various combinations of hardware. The operating system used to implement the whole system is Window XP and corresponding environment.

Safety Critical 시스템의 센서 결함 허용을 위한 Kalman Hybrid Redundancy 개발 (Development of Kalman Hybrid Redundancy for Sensor Fault-Tolerant of Safety Critical System)

  • 김만호;이석;이경창
    • 제어로봇시스템학회논문지
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    • 제14권11호
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    • pp.1180-1188
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    • 2008
  • As many systems depend on electronics, concern for fault tolerance is growing rapidly in the safety critical system such as intelligent vehicle. In order to make system fault tolerant, there has been a body of research mainly from aerospace field including predictive hybrid redundancy by Lee. Although the predictive hybrid redundancy has the fault tolerant mechanism to satisfy the fault tolerant requirement of safety crucial system such as x-by-wire system, it suffers form the variability of prediction performance according to the input feature of system. As an alternative to the prediction method of predictive hybrid redundancy for robust fault tolerant, Kalman prediction has attracted some attention because of its well-known and often-used with its structure called Kalman hybrid redundancy. In addition, several numerical simulation results are given where the Kalman hybrid redundancy outperforms with predictive smoothing voter.

Precision shape modeling by z-map model

  • Park, Jung-Whan;Chung, Yun-Chan;Choi, Byoung-Kyn
    • International Journal of Precision Engineering and Manufacturing
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    • 제3권1호
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    • pp.49-56
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    • 2002
  • 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.

Laser Weld Quality Monitoring System

  • Park, H.;Park, Y.;S. Rhee
    • International Journal of Korean Welding Society
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    • 제1권1호
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    • pp.7-12
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    • 2001
  • Real time monitoring has become critical as the use of laser welding increases. Plasma and spatter are measured and used as the signal for estimating weld quality. The estimating algorithm was made using the fuzzy pattern recognition with the area of data that is beyond the tolerance boundary. Also, an algorithm that detects the spatter and the localized defect was created in order to kd the partially produced pit and the sudden loss of weld penetration. These algorithms were used in quality monitoring of the $CO_2$ laser tailored blank weld. Statistical program that can display the laser weld quality result and the signal transition was made for the first stage of the remote control system.

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모바일 환경에서 Haar-Like Features와 PCA를 이용한 실시간 얼굴 인증 시스템 (Implementation of Realtime Face Recognition System using Haar-Like Features and PCA in Mobile Environment)

  • 김정철;허범근;신나라;홍기천
    • 디지털산업정보학회논문지
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    • 제6권2호
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    • pp.199-207
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    • 2010
  • Recently, large amount of information in IDS(Intrusion Detection System) can be un manageable and also be mixed with false prediction error. In this paper, we propose a data mining methodology for IDS, which contains uncertainty based on training process and post-processing analysis additionally. Our system is trained to classify the existing attack for misuse detection, to detect the new attack pattern for anomaly detection, and to define border patter between attack and normal pattern. In experimental results show that our approach improve the performance against existing attacks and new attacks, from 0.62 to 0.84 about 35%.