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Neha Goel Indivar Gupta M. K. Dubey B. K. Dass 《Applicable Algebra in Engineering, Communication and Computing》2016,27(6):523-535
D. Chaum and H. van Antwerpen first introduced the concept of an undeniable signature scheme where the verification step is verified with the signer’s co-operation. In this paper, first we discuss a combination of Discrete Logarithm Problem (DLP) and Conjugacy Search Problem (CSP) analysing its security. Then we propose an undeniable signature scheme in a non-abelian group over group ring whose security relies on difficulty of the combination of the DLP and the CSP. The complexity and security of our proposed scheme has also been discussed. 相似文献
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Attribute-based group signatures (ABGS) allow a signer to anonymously prove her membership in a group and her ownership of certain attributes, thus can find many applications where both privacy and authentication are required. In this paper, we present a new construction of ABGS based on Fuchsbauer’s automorphic signatures and the Groth and Sahai’s non-interactive witness-indistinguishable proof system. Compared with other ABGS in the literature, our construction is proved secure against fully adaptive adversaries in the standard model, instead of against selected adversaries in the random oracle model. In addition, it admits any signing policies if they can be described as monotone Boolean formulas, and the size of a signature is independent of the number of signers in the group. 相似文献
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Introducing a haptic device into coordinate measuring machine (CMM) inspection path planning leads to the proposal of a novel CMM off-line inspection path planning environment, a haptic virtual coordinate measuring machine (HVCMM), which makes use of the haptic modeling technique for CMM off-line programming. The HVCMM is an accurate model of a real CMM, which simulates a CMM's operation and its measurement process in a virtual environment with haptic perception. In this paper, a simple and effective mechanics model is implemented for the proposed HVCMM. The HVCMM enables CMM off-line programming to take place exactly as if an operator were in front of a real CMM and moving a real CMM probe. Even more, operators can feel the collision between the CMM and a part. Since there is a force feedback when the probe reaches the surface of the part, besides showing the contact in the HVCMM environment, it is much easier to generate a collision-free probe path than using other off-line inspection planning methods. The HVCMM not only facilitates inspection path planning, but also speeds it up because the operator does not need to slow the probe down when it is approaching an object. Combined visual and force feedback is the best indicator for selecting measurement points. 相似文献
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The technology of virtual metrology (VM) has been applied in the semiconductor industry to convert sampling inspection with metrology delay into real time and online total inspection. The purpose of this study is trying to apply VM for inspecting machining precision of machine tools. However, machining processes will cause severe vibrations that make process data collection, data cleaning, and feature extraction difficult to handle. Thus, the tasks of how to accurately segment essential parts of the raw process data from the original numerical-control file, how to effectively handle raw process/sensor data with low signal-to-noise ratios, and how to properly extract significant features from the segmented and clean raw process data are challenging issues for successfully applying VM to machine tools. These issues are judiciously addressed and successfully resolved in this paper. Testing results of machining standard workpieces and cellphone shells of two three-axis CNC machines show that the proposed approach of applying VM to accomplish total precision inspection of machine tools is promising. 相似文献
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In the era of globalization, one of the key factors for manufacturing machine builders/suppliers to remain competitive is their capability to provide cost-effective and comprehensive machine service and maintenance for their clients at anytime, anywhere. Previous research has highlighted the role of virtual engineering tools in the design and development life cycle of manufacturing machinery systems. Virtual engineering models created during the development phase can potentially be used to provide valuable functions for many other tasks during the operational phase, including service and maintenance support. This paper introduces an innovative Internet-enabled three-dimensional-based virtual engineering framework that can be used for such purposes. Specifically, it addresses a system architecture that is designed to facilitate the tight integration between virtual engineering tools and a set of Internet-based reconfigurable modular maintenance supporting tools. This system architecture has been verified by implementations using different toolsets atop of various Internet technologies (e.g. XML Web services and LabView's Datasocket). Implementation details and successful industrial-based test cases are also provided in this paper. 相似文献
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D. H. Norrie C. I. W. Norrie 《International journal for numerical methods in engineering》1986,22(1):241-248
Superproblems in finite elements require either general-purpose or special-purpose computing machines whose capabilities are very much greater than those currently existing. The advantage of the latter type of machine is that it can be highly optimized for the particular class of problem for which it is designed and can, in principle, for a given generation of hardware, be designed to operate at a higher speed than a corresponding general-purpose computer. The Parallel Finite Element Machine (PARFEM) investigated at the University of Calgary has an architecture based on the finite element computational algorithms and employs a combination of parallel and vector processing. The overall architecture and program structure is described and the major design considerations outlined. 相似文献
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The concept of Virtual Enterprise (VE), a special organization of manufacturing units and enterprises, has attracted considerable attention in recent years. Unlike traditional enterprise, VE is most suitable in production environments that experience frequent changes in product mix. To complete a complex task composed of some sub-tasks, traditional control architecture is not versatile enough to coordinate and schedule multi-site and multi-type resources, especially in resolving resource conflicts during operations. Using hybrid control architecture, VE can execute the effective control on multi-site enterprises to support the rapid response to customer demands. Coordination mechanism running through the total life cycle of VE is applied to coordinating and scheduling the requests from different tasks and resources, which make VE flexible, adaptive and robust. In this paper, the hybrid control architecture based on multi-agent technology that supports the cooperation of enterprises is presented. Coordination mechanism and the corresponding optimal models are discussed. Finally a case study is used as an illustration to present the detailed coordination mechanism. 相似文献
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Despite the large number of existing buyer coalition schemes and increasing need for trusting relationship in buyer coalitions, no current buyer coalition scheme explicitly addresses trust issues within these schemes in a formalised manner. Without establishing a trusting relationships among various roles, many buyers may not be willing to join the coalitions. This study proposes a solution, in the form of an algorithmic design, as a response to the above need. Specific features of the proposed solution are: (i) the use of ‘group signature’ in order to guarantees anonymity within a group that results in trustfulness of the relationships and (ii) introducing a new role called ‘authority’ to maintain and implement anonymity. In addition, the proposed scheme is capable of maintaining ‘correctness’ and ‘accountability’ by both identifying misbehaved buyers as well as implementing various punishment methods.Knowledge domain of the study is the common space between three overlapping fields including Electronic Commerce, Communication Technologies and Information Systems. 相似文献
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《中国标准化(英文版)》2021,(3)
正Tian Shihong,Vice-Minister of SAMR and Administrator of SAC,attended the video conference of the China-Germany Working Group on Standardization Strategy taking place on March 1,2021.The German participants include Ole Janssen,Deputy Director General of Innovation and Technology Policy,Federal Ministry for Economic Affairs and Energy (BMWi),Christoph Winterhalter,Chairman of the Executive Board of DIN,as well as Michael Teigeler,Managing Director of DKE. 相似文献
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Global manufacturing enterprises tend to rely on fully integrated manufacturing systems to satisfy constantly changing market requirements. In addition, small to medium enterprises are in a dilemma when competing with large organizations. Virtual computer-integrated manufacturing (VCIM) is a realistic concept that can provide the integration requirements for the globally distributed manufacturing resources and it has the potential to satisfy the market requirements of small to medium enterprises. The vision of the VCIM is to improve the efficiency and effectiveness of manufacturing enterprises by seamlessly integrating globally distributed manufacturing resources as much as possible. Meanwhile, intelligent agent technology provides a better means to implement distributed components as integrated application systems. The paper provides a parallel processing multi-agent architecture to support a global integrated manufacturing system in the form of the VCIM. In this architecture, a three-layered structure is proposed to accommodate all the agents no matter where they are located. Multiple Facilitator agents are proposed with similar functionalities to smooth the information flow across the integrated system in a parallel connection manner. In addition, a multi-agent VCIM model that describes the agent identification approaches for VCIM, Java environment implementation approaches and a simulation system to demonstrate the parallel processing multi-agent architecture are also discussed. 相似文献
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Kinesin is a protein-based natural nanomotor that transports molecular cargoes within cells by walking along microtubules. Kinesin nanomotor is considered as a bio-nanoagent which is able to sense the cell through its sensors (i.e. its heads and tail), make the decision internally and perform actions on the cell through its actuator (i.e. its motor domain). The study maps the agent-based architectural model of internal decision-making process of kinesin nanomotor to a machine language using an automata algorithm. The applied automata algorithm receives the internal agent-based architectural model of kinesin nanomotor as a deterministic finite automaton (DFA) model and generates a regular machine language. The generated regular machine language was acceptable by the architectural DFA model of the nanomotor and also in good agreement with its natural behaviour. The internal agent-based architectural model of kinesin nanomotor indicates the degree of autonomy and intelligence of the nanomotor interactions with its cell. Thus, our developed regular machine language can model the degree of autonomy and intelligence of kinesin nanomotor interactions with its cell as a language. Modelling of internal architectures of autonomous and intelligent bio-nanosystems as machine languages can lay the foundation towards the concept of bio-nanoswarms and next phases of the bio-nanorobotic systems development. 相似文献
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基于虚拟装配的硬币自动包装机设计方法 总被引:3,自引:2,他引:1
为解决硬币处理困难的问题,研究和设计了一种新型台式硬币包装机.在开发过程中采用基于 3D 特征造型和虚拟装配等CAD 技术,应用Pro/E 软件实现了该硬币包装机的三维设计和数字化样机的建立;通过动态仿真和干涉分析,验证了设计方案的可行性.该方法为此种硬币包装机物理样机的制作,和日后产品结构的设计优化提供了快捷有效的途径. 相似文献
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数控机床是一种重要的技术装备。为提高数控机床的设计水平和能力,在数控机床的设计开发过程中需要引入新的技术和设计手段。为把虚拟样机技术应用到数控机床设计开发的工程实践中,基于虚拟样机的概念讨论了数控机床虚拟样机的具体实现过程,分析比较了实现该过程的分布式软件平台和UG集成软件平台的特点。以数控铣床新产品开发为例,研究了UG集成环境下数控机床虚拟样机的构建与仿真过程,包括数字模型与装配、运动仿真、结构分析以及在虚拟样机上的加工仿真,给出了相应的示例。研究表明,应用UG的各功能模块可以有效地构建数控机床的虚拟样机并对其进行全面的仿真,使所设计的数控机床得到全面优化,为数控机床的开发设计提供了一种可行的先进方法。 相似文献
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David Bue Pedersen Eyþór Rúnar Eiríksson Hans Nørgaard Hansen Jakob Skov Nielsen 《Virtual and Physical Prototyping》2016,11(3):227-234
A delta-type parallel kinematics system for Additive Manufacturing has been created, which through a probing system can recognise its geometrical deviations from nominal and compensate for these in the driving inverse kinematic model of the machine. Novelty is that this model is derived from a virtual machine of the kinematics system, built on principles from geometrical metrology. Relevant mathematically non-trivial deviations to the ideal machine are identified and decomposed into elemental deviations. From these deviations, a routine is added to a physical machine tool, which allows it to recognise its own geometry by probing the vertical offset from tool point to the machine table, at positions in the horizontal plane. After automatic calibration the positioning error of the machine tool was reduced from an initial error after its assembly of ±170?µm to a calibrated error of ±3?µm. Excelling by speed, the calibration was executed in less than 3?min. 相似文献
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A vibration data-based machine learning architecture is designed for structural health monitoring (SHM) of a steel plane frame structure. This architecture uses a Bag-of-Features algorithm that extracts the speeded-up robust features (SURF) from the time-frequency scalogram images of the registered vibration data. The discriminative image features are then quantised to a visual vocabulary using K-means clustering. Finally, a support vector machine (SVM) is trained to distinguish the undamaged and multiple damage cases of the frame structure based on the discriminative features. The potential of the machine learning architecture is tested for an unseen dataset that was not used in training as well as with some datasets from entirely new damages close to existing (i.e., trained) damage classes. The results are then compared with those obtained using three other combinations of features and learning algorithms—(i) histogram of oriented gradients (HOG) feature with SVM, (ii) SURF feature with k-nearest neighbours (KNN) and (iii) HOG feature with KNN. In order to examine the robustness of the approach, the study is further extended by considering environmental variabilities along with the localisation and quantification of damage. The experimental results show that the machine learning architecture can effectively classify the undamaged and different joint damage classes with high testing accuracy that indicates its SHM potential for such frame structures. 相似文献
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圆弧齿轮加工用虚拟轴机床伺服系统存在的不确定性会影响系统的性能,从而降低圆弧齿轮的加工精度;同时,滑模控制中抖动现象会影响控制的精度和稳定性.为提高虚拟轴机床的加工精度和抑制滑模控制中的抖动现象,提出了基于改进观测器的滑模变结构控制算法来控制虚拟轴机床的伺服电机,算法中采用该干扰观测器对系统中的不确定性进行观测,利用饱和函数代替符号函数来抑制滑模控制中的抖动现象.推导了基于改进观测器的滑模变结构控制律,并证明了所设计控制器的稳定性;为验证算法的有效性,在MATLAB中进行了仿真,仿真结果表明:所提出的算法能够有效地观测系统中存在的不确定性因素,并抑制滑模控制中的抖动现象,系统具有较强的位置跟踪性能和抗干扰能力. 相似文献