Computer-Aided Design of Traditional Jigs and Fixtures

Conventional design of jigs and fixtures has become unsuitable given the requirements of modern technology and complexity and diversity in the production with the rapid update of products. Computer-aided design (CAD) of jigs and fixtures is an effective solution in this direction. The current paper focuses on a computer-aided design of the traditional jigs and fixtures and developed a system containing tailor-made software, created using the Visual Basic programming language and installed on it the viewer screen to show the part. The developed system has been built by connecting Visual Basic programming language to the SolidWorks software on which the part is drawn and saved as STEP AP-203 file format, and the system reads and extracts the data from the STEP AP-203 file. Heuristic rules of feature recognition are pre-prepared for checking the extracted geometric data and deciding which data shape will represent the machining feature; then, the system provides the optimum design of the traditional jigs and fixtures for a group of hollow cylindrical parts that contain a group of cross-holes on the cylinder body, whether perpendicular or offset from the cylinder’s axis, (inclined or inclined offset, or blind or through, by applying pre-prepared heuristic rules for the design of traditional jigs and fixtures.

Cloud system for decision supporting of technological process of restoration of surfaces of structures and machine parts

The object of research is the process of decision support of the technological process. The subject of the research is the decision support system of the technological process of restoration of surfaces of structures and machine parts in the form of cloud service. The purpose of the work is to develop a decision support system for the technological process of restoration of surfaces of structures and machine parts in the form of cloud service, which will further optimize high-tech processes of enterprises of various scales using cloud information technology. As a result of the research, the difficulties of automating the design of technological processes are analyzed, mainly due to the fact that the tasks of technological process design do not currently have formal methods of solution. Therefore, for the implementation of technological design, the development of formalization of technology (or part of it), ie the replacement (transformation) of meaningful proposals by the mathematical apparatus. As a result of this formalization, a scheme of information flow in the process of process optimization is proposed. the model of realization of structure of technological process for which the basic input parameters are defined is developed: the list of parameters influencing process. The structure of the expert system for optimization of technological processes was also proposed, the methods of knowledge presentation were analyzed and the scheme of information flows during the implementation of this expert system was developed accordingly. Based on the considered and developed methods and mechanisms used for the development of technological processes, the structure of the information cloud decision support system for automation of the creation of optimized technological processes has been developed. Using the developed methods and models, as a result of the process of process optimization according to acceptable heuristic rules, it was possible to obtain a set of chains of separately optimized technological processes, from which multicriteria selection that meets the optimization requirements. The user of the system can receive in return both one card of technological process, and some best. Conclusions. The developed approaches to the optimization of technological processes were applied to solve the problem of optimization of the technological process of electric arc processing. First, the technological process of electric arc processing was formalized. After that, the formation of heuristic rules and knowledge base of the structure of the technological process of electric arc spraying and accordingly developed the structure of the knowledge base of this technological process and a diagram of the use of the developed information system in the form of cloud service.

Defining work-zones for resource allocation in Hong Kong public housing project construction using heuristic rules and operations simulation

In Hong Kong, 6-day construction cycle always being used for constructing one typical floor of concrete building superstructure in a week. Work-zones are defined in the working platform for better allocation of limited resources. Once the work-zones are defined, the resources (labour, plant, materials) will be allocated to a specific zone to deliver the works on a particular day of the 6-day construction cycle. In practice, the definition of work-zone is dependent on the experience of project manager. Yet, there is no past research studied the evaluation of work-zone definition schemes. As such, in this research study, three heuristic rules are proposed for choosing better scheme of work-zone. The heuristic rules are based on (i) lengths of work-zone dividing line, (ii) fluctuations of daily duration, and (iii) utilisation rates of resource. To illustrate the steps of evaluating the scheme, an illustrative example is given. To illustrate the method application of the rules, a practical case study of constructing a 40-storey housing is given. The proposed rules were verified based on sensitivity analysis and expert validation. Conclusions are drawn by expressing the contributions and limitations of the proposed rules, followed by suggesting future research works.

Three-Phase Symmetric Distribution Network Fast Dynamic Reconfiguration Based on Timing-Constrained Hierarchical Clustering Algorithm

This paper develops a novel dynamic three-phase symmetric distribution network reconfiguration (DNR) approach based on hierarchical clustering with timing constraints, which can divide the time period according to the time-varying symmetric load demand and symmetric distributed generations (DGs) output condition for a given time interval. The significance of the proposed technique is that by approximating the cluster center as the load status and DGs output status of the corresponding period, in this way, the intractable dynamic reconfiguration problem can be recast as multiple single-stage static three-phase symmetric DNR problems, which can effectively reduce the complexity of the three-phase symmetric dynamic reconfiguration. Furthermore, an improved fireworks algorithm considering heuristic rules (H-IFWA) is proposed and investigated to efficiently manage each single-stage static three-phase symmetric DNR problem. In order to avoid trapping into a local optimum or to facilitate the computational performance, the power moment method and the coding method based on heuristic rules are employed to reduce the solution space. The effectiveness of the proposed H-IFWA is validated on the IEEE 33, 119-bus system and a practical-scale Taiwan power company (TPC) 84-bus test system with DGs.

Generalizing game-changing species across microbial communities

Microbes form multispecies communities that play essential roles in our environment and health. Not surprisingly, there is an increasing need for understanding if certain invader species will modify a given microbial community, producing either a desired or undesired change in the observed collection of resident species. However, the complex interactions that species can establish between each other and the diverse external factors underlying their dynamics have made constructing such understanding context-specific. Here we integrate tractable theoretical systems with tractable experimental systems to find general conditions under which non-resident species can change the collection of resident communities—game-changing species. We show that non-resident colonizers are more likely to be game-changers than transients, whereas game-changers are more likely to suppress than to promote resident species. Importantly, we find general heuristic rules for game-changers under controlled environments by integrating mutual invasibility theory with in vitro experimental systems, and general heuristic rules under changing environments by integrating structuralist theory with in vivo experimental systems. Despite the strong context-dependency of microbial communities, our work shows that under an appropriate integration of tractable theoretical and experimental systems, it is possible to unveil regularities that can then be potentially extended to understand the behavior of complex natural communities.

An Intelligent Fleet Condition-Based Maintenance Decision Making Method Based on Multi-Agent

According to the demand for condition-based maintenance online decision making among a mission oriented fleet, an intelligent maintenance decision making method based on Multi-agent and heuristic rules is proposed. The process of condition-based maintenance within an aircraft fleet (each containing one or more Line Replaceable Modules) based on multiple maintenance thresholds is analyzed. Then the process is abstracted into a Multi-Agent Model, a 2-layer model structure containing host negotiation and independent negotiation is established, and the heuristic rules applied to global and local maintenance decision making is proposed. Based on Contract Net Protocol and the heuristic rules, the maintenance decision making algorithm is put forward. Finally, a fleet consisting of 10 aircrafts on a 3-wave continuous mission is illustrated to verify this method. Simulation results indicate that this method can improve the availability of the fleet, meet mission demands, rationalize the utilization of support resources and provide support for online maintenance decision making among a mission oriented fleet.