检索结果-内蒙古大学图书馆

Mechanical Assembly Packing Problem Using Joint Constraints

Journal of computer Science & Technology 2017年第6期32卷 1162-1171页

作者： Ming-Liang Xu Ning-Bo Gu Wei-Wei Xu Ming-Yuan Li Jun-Xiao Xue Bing Zhou School of Information Engineering Zhengzhou University Zhengzhou 450000 China State Key Laboratory of Computer Aided Design and Computer Graphics Zhejiang University Hangzhou 310058 China School of Software Zhengzhou University Zhengzhou 450000 China

The three-dimensional packing problem is generally on how to pack a set of models into a given bounding box using the smallest packaging volume. It is known as an NP-hard problem. When discussing the packing problem in mechanical field, the space utilization of a mechanism is low due to the constraint of mechanical joints between different mechanical parts. Although such a situation can be improved by breaking the mechanism into components at every joint, it burdens the user when reassembling the mechanism and may also reduce the service life of mechanical parts. In this paper, we propose a novel mechanism packing algorithm that deliberately considers the DOFs （degrees of freedom） of mechanical joints. With this algorithm, we construct the solution space according to each joint. While building the search tree of the splitting scheme, we do not break the joint, but move the joint. Therefore, the algorithm proposed in this paper just requires the minimal number of splits to meet the goal of space utilization. Numerical examples show that the proposed method is convenient and efficient to pack three-dimensional models into a given bounding box with high space utilization.

关键词： NP-hard problem packing problem search tree

来源：评论

学校读者我要写书评

暂无评论

A microprocessor display controller for combining refresh and storage tube graphics 78

A microprocessor display controller for combining refresh an...

引用

5th Annual Conference on computer graphics and Interactive Techniques, SIGGRAPH 1978

作者： Satterfield, Steven G. Rodriguez, Francisco Rogers, David F. Computer Aided Design and Interactive Graphics Group Division of Engineering and Weapons AnnapolisMD21402 United States

ISBN: (纸本)9781450379083

This paper describes a stand alone graphics system utilizing a microprocessor based display controller with the capability of combining refresh with storage tube graphics. This combination is accomplished by utilizing the Write-Thru feature of a Tektronix 4014 display terminal. The display controller is a typical Z-80 microprocessor system interfaced to the 4014 by a standard Tektronix parallel interface. A portion of the Z-80 memory is used as the display buffer, allowing it to be divided into store and non-store (refreshed) segments. The microprocessor performs the conversion from the simple integer X,Y coordinates in the display buffer to actual Tektronix drawing commands. A second Z-80 microprocessor is used to perform graphical transformations and transfer the data from the PDP-11 host to the Z-80 display controller. The operations performed by the second microprocessor include translation, rotation and scaling. These operations are implemented by matrix multiplication of the user data by a user specified transformation matrix. The stand alone capabilities of the graphics system is made complete with interactive devices such as a tablet, analog dials, and function switches interfaced directly to the host computer. © 1978 Association for Computing Machinery. All rights reserved.

关键词： Storage tubes

来源：评论

学校读者我要写书评

暂无评论

Comparing different teaching models in a first year computer aided design course

Comparing different teaching models in a first year computer...

引用

2005 ASEE Annual Conference and Exposition: The Changing Landscape of engineering and Technology Education in a Global World

作者： Baxter, Douglas H. Mandigo, Andrew CAD/CAM/CAE United States Engineering Graphics and Computer Aided Design Course School of Engineering Rensselaer Polytechnic Institute United States CAD/CAM/CAE School of Engineering Rensselaer Polytechnic Institute United States

The comparison of different teaching models in a first year CAD course is presented. The course, engineering graphics and computer aided design (EG&CAD) teaches the skills of using a solid modeling system to create parts, small assemblies, and documentation. EG&CAD is taught with a series of twelve one hour lectures over a fourteen week semester. The new model of using assembly for the entire semester is proving successful. Moreover, quizzes will no longer be drawn from the final project instead, from other sources.

关键词： computer aided design

来源：评论

学校读者我要写书评

暂无评论

Recent progress and trends in predictive visual analytics

引用

Frontiers of computer Science 2017年第2期11卷 192-207页

作者： Junhua LU Wei CHEN Yuxin MA Junming KE Zongzhuang LI Fan ZHANG Ross MACIEJEWSKI State Key Lab of Computer Aided Design and Computer Graphics Zhejiang University Hangzhou 310058 China College of Science Zhejiang University of Technology Hangzhou 310023 China College of Computer Science and Technology Zhejiang University of Technology Hangzhou 310023 China School of Computing Informatics and Decision Systems Engineering Arizona State University Tempe AZ 85287-8809 USA

A wide variety of predictive analytics techniques have been developed in statistics, machine learning and data mining; however, many of these algorithms take a black-box approach in which data is input and future predictions are output with no insight into what goes on during the process. Unfortunately, such a closed system approach often leaves little room for injecting domain expertise and can result in frustration from analysts when results seem snurious or confusing. In order to allow for more human-centric approaches, the visualization community has begun developing methods to enable users to incorporate expert knowledge into the pre- diction process at all stages, including data cleaning, feature selection, model building and model validation. This paper surveys current progress and trends in predictive visual ana- lytics, identifies the common framework in which predictive visual analytics systems operate, and develops a summariza- tion of the predictive analytics workfiow.

关键词： predictive visual analytics visualization visual analytics data mining predictive analysis

来源：评论

学校读者我要写书评

暂无评论

A simple approach to computer aided milling with interactive graphics 77

A simple approach to computer aided milling with interactive...

引用

4th Annual Conference on computer graphics and Interactive Techniques, SIGGRAPH 1977

作者： Satterfield, Steven G. Rodriguez, Francisco Rogers, David F. Computer Aided Design and Interactive Graphics Group U. S. Naval Academy Division of Engineering and Weapons AnnapolisMD21402 United States

ISBN: (纸本)9781450373555

This paper describes CAMILL, a system for computer aided milling of ship hull models defined with interactive graphics-The major hardware components of CAMILL are a mini-computer based refresh display and a three axis numerically | controlled milling machine. For hardcopy documentation there is a large flatbed plotter. The two major software components are an interactive display program and a cutting program. The interactive display program is the human interface and provides capabilities for creating and modifying the ship design. The cutting program is executed in an intelligent terminal interfaced to the milling machine-The data used by the cutting program is generated by the display program and stored on a magnetic cassete tape. This cassette is transferred to the intelligent terminal for use by the cutting program-The main function of the cutting program is to direct the milling of the desired ship hull.

关键词： Milling (machining)

来源：评论

学校读者我要写书评

暂无评论

computer aided ship design and numerically controlled production of towing tank models 16

Computer aided ship design and numerically controlled produc...

引用

16th design Automation Conference, DAC 1979

作者： Rogers, David F. Francisco Rodriguez, M. Satterfield, Steven G. Division of Engineering and Weapons Computer Aided Design/Interactive Graphics Group U. S. Naval Academy AnnapolisMD21402 United States

A computer aided Ship design (CASD) and a computer aided Manufacturing (CAM) program are described. The objective of the program is to provide the capability to design and manufacture towing tank models using interactive CASD and CAM techniques. A three dimensional interactive graphics device supported by a minicomputer is used to drive the design portion of the system. A microprocessor based graphics system, simply and directly interfaced to a CNC controller on the shop floor, is used to perform the post processing and drive the milling machine. Experiences with actual use of the system and the benefits derived from this use are discussed for an actual production job. © 1979 Institute of Electrical and Electronics Engineers Inc. All rights reserved.

关键词： computer aided manufacturing

来源：评论

学校读者我要写书评

暂无评论

Discovery of Novel Androgen Receptor Ligands by Structure-based Virtual Screening and Bioassays

引用

Genomics, Proteomics & Bioinformatics 2018年第6期16卷 416-427页

作者： Wenfang Zhou Mojie Duan Weitao Fu Jinping Pang Qin Tang Huiyong Sun Lei Xu Shan Chang Dan Li Tingjun Hou College of Pharmaceutical Sciences Zhejiang University State Key Laboratory of Computer Aided Design and Computer Graphics (CAD&GC) Zhejiang University State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics National Center for Magnetic Resonance in WuhanWuhan Institute of Physics and MathematicsChinese Academy of Sciences Institute of Bioinformatics and Medical Engineering School of Electrical and Information EngineeringJiangsu University of Technology

Androgen receptor(AR) is a ligand-activated transcription factor that plays a pivotal role in the development and progression of many severe diseases such as prostate cancer, muscle atrophy, and osteoporosis. Binding of ligands to AR triggers the conformational changes in AR that may affect the recruitment of coactivators and downstream response of AR signaling ***, AR ligands have great potential to treat these diseases. In this study, we searched for novel AR ligands by performing a docking-based virtual screening(VS) on the basis of the crystal structure of the AR ligand binding domain(LBD) in complex with its agonist. A total of 58 structurally diverse compounds were selected and subjected to LBD affinity assay, with five of them(HBP1-3, HBP1-17, HBP1-38, HBP1-51, and HBP1-58) exhibiting strong binding to AR-LBD. The IC50 values of HBP1-51 and HBP1-58 are 3.96 m M and 4.92 m M, respectively, which are even lower than that of enzalutamide(Enz, IC50= 13.87 m M), a marketed second-generation AR antagonist. Further bioactivity assays suggest that HBP1-51 is an AR agonist, whereas HBP1-58 is an AR antagonist. In addition, molecular dynamics(MD) simulations and principal components analysis(PCA) were carried out to reveal the binding principle of the newlyidentified AR ligands toward AR. Our modeling results indicate that the conformational changes of helix 12 induced by the bindings of antagonist and agonist are visibly different. In summary,the current study provides a highly efficient way to discover novel AR ligands, which could serve as the starting point for development of new therapeutics for AR-related diseases.

关键词： Androgen receptor AR ligand Virtual screening AR agonist AR antagonist

来源：评论

学校读者我要写书评

暂无评论

Development of a Control System for a Vibratory Lapping-Polishing Machine 28

Development of a Control System for a Vibratory Lapping-Poli...

引用

28th IEEE International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory, DIPED 2023

作者： Korendiy, Vitaliy Kachur, Oleksandr Zakharov, Viktor Department of Technical Mechanics and Engineering Graphics Lviv Polytechnic National University Lviv Ukraine Department of Computer-Aided Design Lviv Polytechnic National University Lviv Ukraine Department of Technical Mechanics and Engineering Graphics Lviv Polytechnic National UniversityGalca Ltd Lviv Ukraine

ISBN: (纸本)9798350315332

Vibratory equipment is widely used in various fields of mechanical, industrial, and manufacturing engineering. Particularly, such machines can be effectively implemented while carrying out finishing technological operations, e.g., glazing, polishing, and lapping of different machine parts. The present paper is focused on developing the control system for the novel design of a vibratory lapping-polishing machine driven by six solenoids. The main purpose consists in providing the circular trajectory of the working member and ensuring the machining uniformity at each point of the surface being treated. In such a case, it is proposed to actuate the solenoids with the specified time shift depending on the forced frequency needed to be provided. The duration of the signal actuating the solenoid is equal to one-sixth of the total duration of a cycle (period) of the working body oscillation. The corresponding control approach is developed and simulated in the Tinkercad application, while the control system is designed based on the Arduino hardware and software. In addition, the laboratory prototype of the vibratory lapping-polishing machine and the corresponding control system are implemented in practice. The performed laboratory studies and experimental tests substantiate the possibilities of generating the circular oscillations of the working member of the vibration-driven lapping-polishing machine. The obtained results may be useful for engineers and technologists dealing with control systems of various vibratory technological equipment based on electromagnetic and solenoid-type drives. © 2023 IEEE.

关键词： Polishing machines

来源：评论

学校读者我要写书评

暂无评论

Indentation behavior of a semi-infinite piezoelectric semiconductor under a rigid flat-ended cylindrical indenter

引用

Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 649-662页

作者： Shijing GAO Lele ZHANG Jinxi LIU Guoquan NIE Weiqiu CHEN State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Key Laboratory for Mechanics of Intelligent Materials and Structures Department of Engineering MechanicsShijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Computer Aided Design and Computer Graphics Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou 310027China

This paper theoretically studies the axisymmetric frictionless indentation of a transversely isotropic piezoelectric semiconductor(PSC)half-space subject to a rigid flatended cylindrical *** contact area and other surface of the PSC half-space are assumed to be electrically *** the Hankel integral transformation,the problem is reduced to the Fredholm integral equation of the second *** equation is solved numerically to obtain the indentation behaviors of the PSC half-space,mainly including the indentation force-depth relation and the electric potential-depth *** results show that the effect of the semiconductor property on the indentation responses is limited within a certain range of variation of the steady carrier *** dependence of indentation behavior on material properties is also analyzed by two different kinds of *** element simulations are conducted to verify the results calculated by the integral equation technique,and good agreement is demonstrated.

关键词： piezoelectric semiconductor(PSC) insulating indenter electromechanical response singular integral equation finite element simulation

来源：评论

学校读者我要写书评

暂无评论

Robust computation of subcortical functional connectivity guided by quantitative susceptibility mapping: An application in Parkinson's disease diagnosis

引用

NeuroImage 2025年 314卷 121256-121256页

作者： Qin, Jianmei Wu, Haoting Wu, Chenqing Guo, Tao Zhou, Cheng Duanmu, Xiaojie Tan, Sijia Wen, Jiaqi Zheng, Qianshi Yuan, Weijin Zhu, Zihao Chen, Jingwen Wu, Jingjing He, Chenyu Ma, Yiran Liu, Chunlei Xu, Xiaojun Guan, Xiaojun Zhang, Minming Department of Radiology the Second Affiliated Hospital Zhejiang University School of Medicine Hangzhou China Joint Laboratory of Clinical Radiology the Second Affiliated Hospital Zhejiang University School of Medicine Hangzhou China State Key Laboratory of Computer-aided Design & Computer Graphics Zhejiang University College of Computer Science and technology Hangzhou China State Key Laboratory of Industrial Control Technology Zhejiang University College of Control Science and Engineering Hangzhou China Department of Electrical Engineering and Computer Sciences University of California Berkeley CA United States Helen Wills Neuroscience Institute University of California Berkeley CA United States

Previous resting state functional MRI (rs-fMRI) analyses of the basal ganglia in Parkinson's disease heavily relied on T1-weighted imaging (T1WI) atlases. However, subcortical structures are characterized by subtle contrast differences, making their accurate delineation challenging on T1WI. In this study, we aimed to introduce and validate a method that incorporates quantitative susceptibility mapping (QSM) into the rs-fMRI analytical pipeline to achieve precise subcortical nuclei segmentation and improve the stability of RSFC measurements in Parkinson's disease. A total of 321 participants (148 patients with Parkinson's Disease and 173 normal controls) were enrolled. We performed cross-modal registration at the individual level for rs-fMRI to QSM (FUNC2QSM) and T1WI (FUNC2T1), *** consistency and accuracy of resting state functional connectivity (RSFC) measurements in two registration approaches were assessed by intraclass correlation coefficient and mutual information. Bootstrap analysis was performed to validate the stability of the RSFC differences between Parkinson's disease and normal controls. RSFC-based machine learning models were constructed for Parkinson's disease classification, using optimized hyperparameters (RandomizedSearchCV with 5-fold cross-validation). The consistency of RSFC measurements between the two registration methods was poor, whereas the QSM-guided approach showed better mutual information values, suggesting higher registration accuracy. The disruptions of RSFC identified with the QSM-guided approach were more stable and reliable, as confirmed by bootstrap analysis. In classification models, the QSM-guided method consistently outperformed the T1WI-guided method, achieving higher test-set ROC-AUC values (FUNC2QSM: 0.87–0.90, FUNC2T1: 0.67–0.70). The QSM-guided approach effectively enhanced the accuracy of subcortical segmentation and the stability of RSFC measurement, thus facilitating future biomarker development in Parkinso

关键词： Parkinson's disease Quantitative susceptibility mapping Resting-state functional connectivity Subcortical nuclei

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：