In different protocols, wireless sensor networks (WSNs) form different topologies. The reliability evaluation of a WSN whose topology is a chain is studied in this paper. A bidirectional data transmission tree (BDTT) model is established to describe the process of data fusion and transmission on a WSN with a chain structure. From the characteristics of the measurement errors, the number of fusions, and measurement credibility, 3 definitions for the reliability of a BDTT are presented. Based on the universal generating function technique, an algorithm is suggested for evaluating the reliability of a BDTT. In the algorithm, a BDTT model is divided into 2 branches, and 2 new composition operators are defined according to data fusion and transmission. We use the first operator to obtain the u‐function of each branch and the second one to combine the u‐functions of 2 branches and obtain the u‐function of the BDTT. The process of calculating the reliability of a BDTT is illustrated with an example, and the effects of measurement errors, the number of fusions, and measurement credibility on the system reliability are analyzed.
In the era of mass customization, designing optimal products is one of the most critical decision-making for a company to stay competitive. More and more customers like customized products, which will bring challenges to the product line design and the production. If a company adopts consumers' favorite levels, this may lead to lower product reliability, or incompatibility among the components that make up the product. Moreover, it is worth outsourcing certain attribute levels so as to reduce production cost, but customers may dislike these levels because of their delivery delay. If managers consider the compatibility issue, the quality issue, outsource determination, and the delivery due date in the product design and production stages, it will avoid unreasonable product configuration and many unnecessary expenses, thereby bringing benefits to the company. To solve this complicated problem, we establish a nonlinear programming model to maximize a metric about profit, termed as Per-capita-contribution Margin considering Reliability Penalty (PMRP). Since the integrated product line design and production problem is NP-hard, we propose an improved Discrete Imperialist Competitive Algorithm (DICA) that can find a most powerful imperialist (i.e., solution) by the competition among all countries in the world. The proposed DICA is compared with genetic algorithm (GA) and simulated annealing (SA) through extensive numerical experiment, and the results show that DICA has more attractive performance than GA and SA.
At present, most factories choose cutting parameters only depending on experience or handbooks in production. To improve the intelligent level of cutting parameter selection, Case-Based Reasoning (CBR) is used to search rational cutting parameters. The structure of a CBR-based cutting parameter selection system is presented and its functional modules are discussed. CBR-based cutting parameter selection system is mainly composed of case base management system, cutting parameter database management system, application, interface, etc. A complete case is composed of four parts, i.e., objectives, initial conditions, constraints and results. The system adopts hierarchical searching method in combination with nearest neighbor method. It provides a scientific approach for selecting cutting parameters in actual production.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.