ANALYSIS AND IMPROVEMENT OF LEAD TIME FOR JOB SHOP UNDER MIXED PRODUCTION SYSTEM

Firstly an overview of the potential impact on work-in-process （WIP） and lead time is provided when transfer lot sizes are undifferentiated from processing lot sizes. Simple performance examples are compared to those from a shop with one-piece transfer lots. Next, a mathematical programming model for minimizing lead time in the mixed-model job shop is presented, in which one-piece transfer lots are used. Key factors affecting lead time are found by analyzing the sum of the longest setup time of individual items among the shared processes （SLST） and the longest processing time of individual items among processes （LPT）. And lead time can be minimized by cutting down the SLST and LPT. Reduction of the SLST is described as a traveling salesman problem （TSP）, and the minimum of the SLST is solved through job shop scheduling. Removing the bottleneck and leveling the production line optimize the LPT. If the number of items produced is small, the routings are relatively short, and items and facilities are changed infrequently, the optimal schedule will remain valid. Finally a brief example serves to illustrate the method.

APPLICATION OF IMPROVED PRODUCTION ACTIVITY CONTROL ARCHITECTURE FOR SHOP FLOOR INFORMATION SYSTEM IN DIGITAL MANUFACTURING

Shop floor control （SFC） is responsible for the coordination and control of the manufacturing physical and information flow within the shop floor in the manufacturing system. Weaknesses of the production activity control （PAC） architecture of the shop floor are addressed by the Maglica＇s new system architecture. This architecture gives rise to unlimited number of movers and producers thus evolving more complex but decentralized architecture. Beijing Institute of Technology - production activity control （BIT-PAC） architecture introduces an idea of sub-producars and sub-movers thus reducing the complexity of the architecture. All the equipments including sub-producars and sub-movers are considered to be passive in the proposed shop floor information system. The dissemination of information from sub-producers and sub-movers is done manually through a PC. Proposed BIT-PAC SFC architecture facilitates the information flow from shop floor to the other area of the organization. Effective use of interact information services （IIS） and SQL2000 is done along with the ASP.NET technology to implement the application logic. Applicability of the software based on BIT-PAC architecture is checked by running application software on a network PC that supports the dynamic flow of information from sub-producers and sub-movers to the other parts of the organization. Use of software is also shown at the end for BIT training workshop thus supporting the use of SFC architecture for similar kind of environments.

A Research on Senior People Online Consumption in China-From Perspective of Providing Technology Support

While the internet skills of the elderly is no longer a big problem,it is still necessary to further improve the online shopping experience and activity of the elderly.Evidently,the frequency of seniors shopping online is not nearly as high as the younger generation,as the elderly online shopping frequency is still calculated by weeks.People with higher education and younger age are more likely to accept technology products and understand how to use them,but people with lower education and older age will find it harder to use technology product.The majority of the elderly have a vision for the further development of technology to help them.This study shows that the elderly group shopping demand is large,but when the majority of the elderly choose offline consumption,the option of just a simple online solution is insufficient.Some shopping apps have made improvements in such aspects as font enlargement,color contrast enhancement and simplified operation steps.However,these improvements only solved the superficial problems,and failed to consider and solve the problems based on the experience of the elderly.