Generic Simulation of an Automated Assembly

2013 ◽  
Vol 740 ◽  
pp. 14-26
Author(s):  
Thembelani Sithebe

System design generally involves making long-term decisions such as facility layout and system capacity/configuration. As such, models are typically created and used for a single design exercise, and model run time is not a significant factor during the simulation process. The simulation process is based on the use of Simio standard simulation program. This chapter comprises of a generic workstation diagram that shows a setup of an ideal assembly line. This assembly diagram is the basis from which a flowchart/ algorithm is derived from. The assembly line consists of workstations (one to some given number N). N in case is six. Each workstation is fed by buffer storage areas which are continuously replenished according to the supply conditions of the program. A transporter transports the assembly in between stations. This transporter can either be a conveyor as is with Arena, or a vehicle, as is the case in the Simio program. The Generic Flowchart is based on the Generic Assembly Diagram. The given steps from the identification of the component to has the component has been assembled? occur in one assembler and are for one component. These activities (flowchart) are repeated for each component up to the required number of components that make-up the product, i.e. the loops are repeated for each component in the assembly process. The purpose of this paper is to establish a generic simulation process, which will be based on the generic algorithm and generic assumptions to be used to simulate an automated assembly process. In this generic program, the following parameters can be varied: number of workstations, number of components, and order of assembly, cycle time, time to assembly, component and workstation availability and buffer capacity.

2013 ◽  
Vol 740 ◽  
pp. 27-38 ◽  
Author(s):  
Thembelani Sithebe

Most research has been concentrating on getting input from and simulating specific assembly processes. The most advanced simulation research is based on data driven methods. The rest of simulation articles are case study based. This work envisages establishing a generic simulation process, which will be based on the generic algorithm and generic assumptions to be used to simulate an automated assembly process. The simulation model is based on proposed configuration and operational information. It is used to verify that the proposed system will meet required production rates and, to predict the relative performance of alternative configurations. It can be used for what-if analysis to investigate different operation scenarios and optimize production systems. Validation of the result was done through the use of different scenarios. It is only by using the model to answer specific questions about ways of changing the system that realizable improvements are identified.


Algorithms ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 80
Author(s):  
Qiuqi Han ◽  
Guangyuan Zheng ◽  
Chen Xu

Device-to-Device (D2D) communications, which enable direct communication between nearby user devices over the licensed spectrum, have been considered a key technique to improve spectral efficiency and system throughput in cellular networks (CNs). However, the limited spectrum resources cannot be sufficient to support more cellular users (CUs) and D2D users to meet the growth of the traffic data in future wireless networks. Therefore, Long-Term Evolution-Unlicensed (LTE-U) and D2D-Unlicensed (D2D-U) technologies have been proposed to further enhance system capacity by extending the CUs and D2D users on the unlicensed spectrum for communications. In this paper, we consider an LTE network where the CUs and D2D users are allowed to share the unlicensed spectrum with Wi-Fi users. To maximize the sum rate of all users while guaranteeing each user’s quality of service (QoS), we jointly consider user access and resource allocation. To tackle the formulated problem, we propose a matching-iteration-based joint user access and resource allocation algorithm. Simulation results show that the proposed algorithm can significantly improve system throughput compared to the other benchmark algorithms.


2000 ◽  
Author(s):  
S. Jack Hu ◽  
Yufeng Long ◽  
Jaime Camelio

Abstract Assembly processes for compliant non-rigid parts are widely used in manufacturing automobiles, furniture, and electronic appliances. One of the major issues in the sheet metal assembly process is to control the dimensional variation of assemblies throughout the assembly line. This paper provides an overview of the recent development in variation analysis for compliant assembly. First, the unique characteristics of compliant assemblies are discussed. Then, various approaches to variation modeling for compliant assemblies are presented for single station and multi-station assembly lines. Finally, examples are given to demonstrate the applications of compliant assembly variation models.


2014 ◽  
Vol 29 (4) ◽  
pp. 321-325
Author(s):  
Jovica Praskalo ◽  
Jasna Davidovic ◽  
Biljana Kocic ◽  
Monika Zivkovic ◽  
Svetlana Pejovic

In order to set up a successful mammography screening program in the Republic of Srpska, a Siemens Mammomat 1000 X-ray machine was selected for analysis as the said mammography system is widely used in clinical practice. The variations in tube parameters (specific air kerma, high-voltage accuracy and reproducibility, linearity between exposure and dose exposure time) were monitored over a five-year period, from 2008 to 2012. In addition, due to observed daily fluctuations for chosen parameters, a series of measurements were performed three times a day within a single-month period (mainly October 2012). The goal of such an experimental set up is to assess short-term and long-term stability of tube parameters in the given mammography unit and to make a comparison between them. The present paper shows how an early detection of significant parameter fluctuations can help eliminate irregularities and optimize the performance of mammography systems.


2021 ◽  
Vol 24 (1) ◽  
pp. 57-73
Author(s):  
Константин Павлович Беляев ◽  
Гурий Михайлович Михайлов ◽  
Алексей Николаевич Сальников ◽  
Наталия Павловна Тучкова

The paper analyzes the statistical and temporal seasonal and decadal variability of the atmospheric pressure field in the Arctic region of Russia. Schemes for the frequency analysis of probability transitions for characteristics of stochastic-diffusion processes were used as the main research method. On the basis of the given series of 60 years long from 1948 to 2008, such parameters of diffusion processes as the mean (drift process) and variance (diffusion process) were calculated and their maps and time curves were constructed. The seasonal and long-term variability of calculated fields was studied as well as their dependencies on a discretization of the frequency intervals. These characteristics were analyzed and their geophysical interpretation was carried out. In particular, the known cycles of solar activity in 11 and 22 years were revealed. Numerical calculations were performed on the Lomonosov-2 supercomputer of the Lomonosov Moscow State University.


2015 ◽  
Vol 10 (1) ◽  
pp. 46-56 ◽  
Author(s):  
László Balázs

AbstractThe data necessary for the empirical research presented it this study were provided by 572 people, from altogether 26 schools. The schools included 18 primary schools, 7 secondary training institutions and 1 primary and secondary school. The major question of the study related to the pedagogues' emotional intelligence, more precisely if the teachers of different institutions showed any individual differences in their emotional intelligence patterns according to the given type of their school's organisational culture. We also examined if the nature of the organizational culture had any influence on the development the individual's emotional intelligence pattern. On the basis of the results we can declare that the teachers of different institutions having their own particular organizational cultures evolve different emotional intelligence patterns. Accordingly, we can come to the conclusion that in the long term the organizational culture affects the evolution of the individual's emotional intelligence pattern and vice versa.


Last Subway ◽  
2020 ◽  
pp. 124-156
Author(s):  
Philip Mark Plotch

This chapter recounts how New York City Transit Authority rail service planners Peter Cafiero, Chuck Kirchner, Glenn Lunden, and Jon Melnick resurrected the Second Avenue subway in 1988. Even though the Transit Authority was in the early stages of its 1987–91 capital program, the planners' bosses wanted to start getting ready for the next program, which would run from 1992 to 1996. The first step would be to create a document that assessed the authority's long-term needs and identified projects that would rehabilitate the subway system, increase ridership, improve productivity, and expand system capacity. One proposal the planners wrote to address the Lexington Avenue's problems was an idea that the MTA planner Bob Olmsted had first championed in 1975—a Second Avenue subway north of 63rd Street. As the Second Avenue subway proposal moved up the Transit Authority hierarchy, the authority's president, David Gunn, agreed that the time was right to begin thinking about expanding the subway system. Before he could devote significant resources to advancing the Second Avenue subway, however, it would have to compete with other potential megaprojects under discussion at the MTA's agencies.


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