多传感器检测中的数据溶合技术

多传感器检测是使用多种(或多个)传感器对同一被测对象进行广泛的测量。应用多传感器检测技术和多传感器数据溶合技术对车削加工中的零件外圆尺寸检测进行了实验研究,结果表明,多传感器检测技术能够满足现代检测技术对信息的精确要求,使得检测监控系统更加准确、可靠。     

Association-Based Active Access Control models with balanced scalability and flexibility

In existing Active Access Control (AAC) models, the scalability and flexibility of security policy specification should be well balanced, especially: (1) authorizations to plenty of tasks should be simplified; (2) team workflows should be enabled; (3) fine-grained constraints should be enforced. To address this issue, a family of Association-Based Active Access Control (ABAAC) models is proposed. In the minimal model ABAAC₀, users are assigned to roles while permissions are assigned to task-role associations. In a workflow case, to execute such an association some users assigned to its component role will be allocated. The association's assigned permissions can be performed by them during the task is running in the case. In ABAAC₁, a generalized association is employed to extract common authorizations from multiple associations. In ABAAC₂, a fine-grained separation of duty (SoD) is enforced among associations. In the maximal model ABAAC₃, all these features are integrated, and similar constraints can be specified more concisely. Using a software workflow, case validation is performed. Comparison with a representative association based AAC model and the most scalable AAC model so far indicates that: (1) enough scalability is achieved; (2) without decomposition of a task, different permissions can be authorized to multiple roles in it; (3) separation of more fine-grained duties than roles and tasks can be enforced.     

基于元数据的柔性信息系统建模与实现

介绍数据柔性、数据柔性分析等相关概念。通过引入元数据,提出并建立数据柔性的层次模型和柔性数据的访问模型,以解决用户数据结构如何适应转化的关键问题。在数据柔性分析与建模中,提出以元数据为核心的软件设计方法,并将该方法和所建立的数据柔性理论应用于柔性软件信息系统的开发和软件工程实践中。     

Unlocking the value of flexibility of behind-the-meter prosumers: An overview of mechanisms to esteemed trends

Behind-the-meter (BTM) resources is being recognized as a viable solution to offer grid services including flexibility procurement which is required for volatile renewable power systems. This paper brings an overview of current and esteemed frameworks and respective challenges revolving around BTM flexibility notion and mechanisms. To begin with, we review grid architectures, e.g., microgrids and virtual power plants, capable of accommodating BTM flexibility and desirable flexibility market designs, including peer-to-peer trading. The role of machine learning initiatives, including reinforcement learning and probabilistic forecasting, in designing reliable energy management systems is extensively deliberated. Last but not least, supplementary discussions in making this concept a reality, which can be regarded as future research, are given.     

Modular architecture of the microfactories for automatic micro-assembly

The construction of a new generation of MEMS which includes micro-assembly steps in the current microfabrication process is a big challenge. It is necessary to develop new production means named micromanufacturing systems in order to perform these new assembly steps. The classical approach called “top-down” which consists in a functional analysis and a definition of the tasks sequences is insufficient for micromanufacturing systems. Indeed, the technical and physical constraints of the microworld (e.g. the adhesion phenomenon) must be taken into account in order to design reliable micromanufacturing systems. A new method of designing micromanufacturing systems is presented in this paper. Our approach combines the general “top-down” approach with a “bottom-up” approach which takes into account technical constraints. The method enables to build a modular architecture for micromanufacturing systems. In order to obtain this modular architecture, we have devised an original identification technique of modules and an association technique of modules. This work has been used to design the controller of an experimental robotic micro-assembly station.     

Multi-objective FMS process planning with various flexibilities using a symbiotic evolutionary algorithm

This paper presents an evolutionary algorithm, called the multi-objective symbiotic evolutionary algorithm (MOSEA), to solve a multi-objective FMS process planning (MFPP) problem with various flexibilities. The MFPP problem simultaneously considers four types of flexibilities related to machine, tool, sequence, and process and takes into account three objectives: balancing the machine workload, minimizing part movements, and minimizing tool changes. The MOSEA is modeled as a two-leveled structure to find a set of well-distributed solutions close to the true Pareto optimal solutions. To promote the search capability of such solutions, two main processes imitating symbiotic evolution and endosymbiotic evolution are introduced, together with an elitist strategy and a fitness sharing scheme. Evolutionary components suitable for the MFPP problem are provided. With a variety of test-bed problems, the performance of the proposed MOSEA is compared with those of existing multi-objective evolutionary algorithms. The experimental results show that the MOSEA is promising in solution convergence and diversity.     

Does prolonged sitting with limited legroom affect the flexibility of a healthy subject and their perception of discomfort?

This study examined for differences in subjective ratings of discomfort and comfort (Numerical Rating Scale) and objective measures of hamstring (Sit-Reach test), lumbar (Schöber’s test) and neck (Cervical Range of Motion) flexibility in healthy young subjects (n = 24) following 4 h of sitting on stacking chairs with or without limited legroom.When comparing the limited and unlimited legroom groups for differences in subjective and objective measures over 4 h, no significant findings were seen at the 5% level of confidence. However, differences in buttock, neck, shoulder and average discomfort were significantly negatively correlated to differences between post-warm up Sit-Reach scores (Correlation Co-efficients: −.763, −.434, −.408, and −.445; p values of .004, .034, .048, and .029, respectively). The difference in buttock discomfort was significantly negatively correlated to the difference between pre-warm up Sit-Reach scores (Correlation Coefficient: −.750; p = 0.005), post-sitting/pre-warm up and pre-sitting/post-warm up Sit-Reach scores (Correlation Coefficient: −.756; p = 0.004), and Schöber’s tests (Correlation Coefficient: −.578; p = 0.049).Although the above results suggest a relationship between a loss in flexibility and an increase in discomfort, the mechanism influencing this relationship is not clear from this study. What does appear clear is that the limiting of legroom to the parameters used in this study does not seem to exacerbate change in flexibility and discomfort which are a consequence of prolonged sitting.

Relevance to industry

Many forms of public transport provide limited legroom for their passengers, which may have an adverse affect on the user’s flexibility or experience of discomfort. Determining which objectively measurable parameters are associated with the subjective level of discomfort during sitting should allow for a greater appreciation of the changes that underpin such subjective perceptions.     

基于解释器技术的注塑模CAD系统研究

针对传统泣塑模CAD系统的缺陷，提出并分析了新型注塑模系统的总体设计方案和3DMCAD／CAM系统构建语言，由此实现了柔性化注塑模CAD系统，包括模架、抽芯机构、浇口套等机构及其孔型的信息获取、自动生成、更新和删除。     

Intensified hydroformylation as an example for flexible intermediates production

One of the future challenges for chemical engineering is the design of flexible plants allowing an adaptation of production output to market development. Consequently, the target for the design of new processes must be the identification of equipment allowing such an expansion close to market development. To leverage the full benefit of this approach flexibility analysis has to be integrated into process design workflow. In this article the conventional technology for hydroformylation is compared to an intensified process design. This new design consists of a jet loop reactor followed by a membrane section to separate and recycle the homogenous catalyst. In the first part of the article it will be shown that process intensification leads to a net present value improvement of 30% compared to state of the art hydroformylation at a capacity of 100 kt/a. In the second part suitability of the intensified process for a stepwise plant expansion will be demonstrated. In an expansion scenario with two steps equivalent annual annuity is increased by 5% compared to a one step investment.     

Load following control and global stability analysis for PWR core based on multi-model,LQG, IAGA and flexibility idea

The work is to design a nonlinear Pressurized Water Reactor (PWR) core load following control system and analyze the global stability of this system. On the basis of modeling a nonlinear PWR core, linearized models of the core at five power levels are chosen as local models of the core to substitute the nonlinear core model in the global range of power level. The combination control strategy of the Linear Quadratic Gaussian (LQG) control and the Proportional Integral Derivative (PID) control with an optimization process of Improved Adaptive Genetic Algorithm (IAGA) proposed is used to contrive a combined controller with the robustness of a core local model as a local controller of the nonlinear core. Based on the local models and local controllers, the flexibility idea of modeling and control is presented to design a decent controller of the nonlinear core at a random power level. A nonlinear core model and a flexibility controller at a random power level compose a core load following control subsystem. The combination of core load following control subsystems at all power levels is the core load following control system. The global stability theorem is deduced to define that the core load following control system is globally asymptotically stable within the whole range of power level. Finally, the core load following control system is simulated and the simulation results show that the control system is effective.