23 resultados para Computer-Aided Design


Relevância:

80.00% 80.00%

Publicador:

Resumo:

环形加速器注入引出方法的研究对提高环内束流的强度、提高引出效率以及束流品质,具有重要的意义。本文对一些常用的环形加速器注入引出方法作了较为详细的研究,并着重对单圈注入、多圈注入与射频堆积以及束流冷却的有机结合作了理论研究和计算机模拟,从理论上实现了重离子束的快速累积。并建立了较完整的计算机程序,对这些多过程的结合进行了模拟,获得了与实验相符的结果。这一理论工作在国内尚属首次,在国际上重离子储存环领域中也是重要的新课题。 本文的研究重点是围绕兰州重离子加速器冷却储存环(HIRFL-CSR)注入引出系统的设计,对CSR主环的多圈注入、射频堆积等束流累积过程、主环的快引出和慢引出过程以及实验环的单圈注入过程进行了详细的计算机模拟,为CSR的束流累积、注入引出系统的工程设计提供了理论依据。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Mammographic mass detection is an important task for the early diagnosis of breast cancer. However, it is difficult to distinguish masses from normal regions because of their abundant morphological characteristics and ambiguous margins. To improve the mass detection performance, it is essential to effectively preprocess mammogram to preserve both the intensity distribution and morphological characteristics of regions. In this paper, morphological component analysis is first introduced to decompose a mammogram into a piecewise-smooth component and a texture component. The former is utilized in our detection scheme as it effectively suppresses both structural noises and effects of blood vessels. Then, we propose two novel concentric layer criteria to detect different types of suspicious regions in a mammogram. The combination is evaluated based on the Digital Database for Screening Mammography, where 100 malignant cases and 50 benign cases are utilized. The sensitivity of the proposed scheme is 99% in malignant, 88% in benign, and 95.3% in all types of cases. The results show that the proposed detection scheme achieves satisfactory detection performance and preferable compromises between sensitivity and false positive rates.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

It is necessary to generate the automorphism group of a chemical graph in computer-aided structure elucidation. In this paper, an algorithm was developed by the all-paths topological symmetry algorithm to build the automorphism group of a chemical graph. A comparison of several topological symmetry algorithms reveals that the all-paths algorithm (APA) could yield the correct class of a chemical graph. It lays a foundation for the ESESOC system in computer-aided structure elucidation.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Circadian growth rhythm of the juvenile sporophyte of the brown alga Undaria pirznatifida was measured with the computer-aided image analysis system in constant florescent white light under constant temperature (10 degrees C). The growth rhythm persisted for 4 d in constant light with a free-running period of 25. 6 h. Egg release from filamentous gametophytes pre-cultured in the light - dark regime was evaluated for six consecutive days at fixed time intervals in constant white light and 12 h light per day. Egg release rhythm persisted for 3 d in both regimes, indicating the endogenous nature. Temporal scale of egg release and gametogenesis in 18, 16, 12 and 8 h light per day were evaluated respectively using vegetatively propagated filamentous gametophytes. Egg release occurred 2 h after the onset of dark phase and peaked at midnight. Evaluation of the rates of oogonium formation, egg release or fertilization revealed no significant differences in four light-dark regimes, indicating; the great plasticity of sexual reproduction. No photoperiodic effect in gametogenesis in terms of oogonium formation and egg release was found, but fertilization in short days was significantly higher than in long days. Results of this investigation further confirmed the general occurrence of circadian rhythms in inter-tidal seaweed species.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

本文介绍了一个 CIMS环境下的基于范例的船体装配 CAPP系统 .包括 :CAPP系统在渤海造船厂 CIMS工程中的地位 ,基于范例的工艺规划 (范例的表达 ,范例的索引、存储、检索和适应 ) ,工艺定额和材料定额制定 ,分系统之间的信息集成 .系统采用 Power Builder和 SQL Server数据库中的 SQL语言编写 .目前 ,船体装配 CAPP系统已经在渤海造船厂的微机上连网运行

Relevância:

80.00% 80.00%

Publicador:

Resumo:

本文介绍了多代理技术在船体装配 CAPP系统中应用 .包括 :船体装配 CAPP系统的结构 ,Agent之间的通讯 ,Agent表达方法、提供的函数功能描述 ,以及各工艺代理的功能描述和封装实例 ;采用多代理技术的船体装配 CAPP系统可以生成满足工厂要求的装配工艺文件、工艺定额和材料定额

Relevância:

80.00% 80.00%

Publicador:

Resumo:

介绍了一个较为通用的基于知识的计算机辅助工艺设计(CAPP)系统结构,包括知识表达和关联函数,知识库管理,任务分解与综合策略,解释机制,与其他系统的接口。