Flexible scheduling of diagnostic tests in automotive manufacturing

AbstractThe car of the future will be driven by software and offer a variety of customisation options. Enabling these customisation options forces modern automotive manufacturers to update their standardised scheduling concepts for testing and commissioning cars. A flexible scheduling concept means that every chosen customer configuration code must have its own testing procedure. This concept is essential to provide individual testing workflows where the time and resources are optimised for every car. Manual scheduling is complicated due to constraints on time, predecessor-successor relationships, mutual exclusion criteria, resources and status conditions on the car engineering and assembly line. Applied methods to handle the mathematical formulation for the corresponding industrial optimisation problem and its implementation are not yet available. This paper presents a procedure for automated and non-preemptive scheduling in the testing and commissioning of cars, which is built on a Boolean satisfiability problem on parallel and identical machines with temporal and resource constraints. The presented method is successfully implemented and evaluated on a variant assembly line of an automotive Original Equipment Manufacturer. This paper is the starting point for an automated workflow planning and scheduling process in automotive manufacturing.

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A bi-objective integer programming model for locating garbage accumulation points: a case study

Revista Facultad de Ingeniería Universidad de Antioquia ◽

10.17533/udea.redin.20190509 ◽

2019 ◽

pp. 70-81

Author(s):

Diego Gabriel Rossit ◽

Sergio Nesmachnow ◽

Jamal Toutouh

Keyword(s):

Integer Programming ◽

Local Governments ◽

Programming Model ◽

Mathematical Formulation ◽

Msw Management ◽

Accumulation Points ◽

Starting Point ◽

Support Tools ◽

The City

Enhancing efficiency in Municipal Solid Waste (MSW) management is crucial for local governments, which are generally in charge of collection, since this activity explains a large proportion of their budgetary expenses. The incorporation of decision support tools can contribute to improve the MSW system, specially by reducing the required investment of funds. This article proposes a mathematical formulation, based on integer programming, to determine the location of garbage accumulation points while minimizing the expenses of the system, i.e., the installment cost of bins and the required number of visits the collection vehicle which is related with the routing cost of the collection. The model was tested in some scenarios of an important Argentinian city that stills has a door-to-door system, including instances with unsorted waste, which is the current situation of the city, and also instances with source classified waste. Although the scenarios with classified waste evidenced to be more challenging for the proposed resolution approach, a set of solutions was provided in all scenarios. These solutions can be used as a starting point for migrating from the current door-to-door system to a community bins system.

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Pragmatic truth and approximation to truth

Journal of Symbolic Logic ◽

10.2307/2273956 ◽

1986 ◽

Vol 51 (1) ◽

pp. 201-221 ◽

Cited By ~ 52

Author(s):

Irene Mikenberg ◽

Newton C. A. da Costa ◽

Rolando Chuaqui

Keyword(s):

Mathematical Formulation ◽

Theory Of Knowledge ◽

Major Influence ◽

Mathematical Treatment ◽

Starting Point ◽

Pragmatic Truth ◽

Classical Correspondence ◽

Great Progress ◽

And Mathematics

There are several conceptions of truth, such as the classical correspondence conception, the coherence conception and the pragmatic conception. The classical correspondence conception, or Aristotelian conception, received a mathematical treatment in the hands of Tarski (cf. Tarski [1935] and [1944]), which was the starting point of a great progress in logic and in mathematics. In effect, Tarski's semantic ideas, especially his semantic characterization of truth, have exerted a major influence on various disciplines, besides logic and mathematics; for instance, linguistics, the philosophy of science, and the theory of knowledge.The importance of the Tarskian investigations derives, among other things, from the fact that they constitute a mathematical, formal mark to serve as a reference for the philosophical (informal) conceptions of truth. Today the philosopher knows that the classical conception can be developed and that it is free from paradoxes and other difficulties, if certain precautions are taken.We believe that is not an exaggeration if we assert that Tarski's theory should be considered as one of the greatest accomplishments of logic and mathematics of our time, an accomplishment which is also of extraordinary relevance to philosophy, as we have already remarked.In this paper we show that the pragmatic conception of truth, at least in one of its possible interpretations, has also a mathematical formulation, similar in spirit to that given by Tarski to the classical correspondence conception.

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Cycle Time Reduction in Automotive Manufacturing

The Journal of Social Sciences Research ◽

10.32861/jssr.spi6.1086.1090 ◽

2018 ◽

pp. 1086-1090

Author(s):

Wesam Ali Husien ◽

Waleed Khalid Abduljabbar ◽

Saba Noori Attallh

Keyword(s):

Continuous Improvement ◽

Cycle Time ◽

Assembly Line ◽

Line Balancing ◽

Automotive Manufacturing ◽

Automotive Component ◽

Continuous Improvement Process ◽

Common Problems ◽

Port Klang ◽

Area Data

Today, there are a lot of problems occur in the Automotive Component Manufacturer Company. Amongst them, work not standardized on each process is the most serious one. Standardization work can help reduce the amount of time to complete the task without defects by efficiently guiding the operators. Other related problems include machines fail to clamp semi-finished products to the next station, stopper loose, and rework process which cause the car carpet size to miss the standards. All these common problems increased the cycle time of the car carpet assembly line. So, this study was aimed to investigate how to reduce cycle time of the car carpet assembly line in the Automotive Component Manufacturer Company which located at Port Klang area. Data was collected through interview and observation. To reduce the cycle time of the car carpet assembly line, Kaizen activity and line balancing are implemented. Kaizen is the continuous improvement process. Line balancing is used to manage the workloads among assemblers, to determine number of workstation and to reduce production cost of the company. The derived results show that the cycle time of the car carpet assembly line is reduced from 313 seconds to 131 seconds. This proves that kaizen activities and line balancing do improve the productivity up to 58%. However, to achieve more successful and effective improvement, further work standardization on each process is needed.

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The Heisenberg Indeterminacy Principle in the Context of Covariant Quantum Gravity

Entropy ◽

10.3390/e22111209 ◽

2020 ◽

Vol 22 (11) ◽

pp. 1209

Author(s):

Massimo Tessarotto ◽

Claudio Cremaschini

Keyword(s):

Quantum Gravity ◽

Proper Time ◽

Relativistic Quantum ◽

Mathematical Formulation ◽

Relativistic Quantum Mechanics ◽

Covariant Quantum ◽

Conjugate Momentum ◽

Starting Point ◽

The Subject ◽

Suitable Notion

The subject of this paper deals with the mathematical formulation of the Heisenberg Indeterminacy Principle in the framework of Quantum Gravity. The starting point is the establishment of the so-called time-conjugate momentum inequalities holding for non-relativistic and relativistic Quantum Mechanics. The validity of analogous Heisenberg inequalities in quantum gravity, which must be based on strictly physically observable quantities (i.e., necessarily either 4-scalar or 4-vector in nature), is shown to require the adoption of a manifestly covariant and unitary quantum theory of the gravitational field. Based on the prescription of a suitable notion of Hilbert space scalar product, the relevant Heisenberg inequalities are established. Besides the coordinate-conjugate momentum inequalities, these include a novel proper-time-conjugate extended momentum inequality. Physical implications and the connection with the deterministic limit recovering General Relativity are investigated.

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An Entropy-based Mathematical Formulation for Straight Assembly Line Balancing Problem

International Journal of Strategic Decision Sciences ◽

10.4018/ijsds.2016040104 ◽

2016 ◽

Vol 7 (2) ◽

pp. 57-68 ◽

Cited By ~ 5

Author(s):

Ahmad Heydari ◽

Ali Mahmoodirad ◽

Sadegh Niroomand

Keyword(s):

Objective Function ◽

Assembly Line ◽

Mathematical Formulation ◽

Assembly Line Balancing ◽

Work Load ◽

Line Balancing ◽

Similar Work ◽

Variable Approach ◽

Assembly Line Balancing Problem ◽

Simple Assembly

This paper focuses on formulating a typical simple assembly line balancing problem. A new objective function based on a nonlinear entropy function is considered for the simple assembly line balancing problem for the first time. This objective function force the stations to have more similar total task processing time, so that the workers of the stations will have similar work load. Using a bounded variable approach, the nonlinear objective function is converted to an approximated linear objective function. Finally, efficiency of the linearized formulation of the entropy-based assembly line balancing problem is tested by a numerical example.

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Optimisation of Assembly Line Balancing Type-E with Resource Constraints Using NSGA-II

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.701.195 ◽

2016 ◽

Vol 701 ◽

pp. 195-199 ◽

Cited By ~ 1

Author(s):

Masitah Jusop ◽

Mohd Fadzil Faisae Ab Rashid

Keyword(s):

Genetic Algorithm ◽

Assembly Line ◽

Resource Constraints ◽

Hybrid Genetic Algorithm ◽

Assembly Line Balancing ◽

Search Space ◽

Line Balancing ◽

Benchmark Problems ◽

Nsga Ii ◽

Multi Objective Genetic Algorithm

Assembly line balancing of Type-E problem (ALB-E) is an attempt to assign the tasks to the various workstations along the line so that the precedence relations are satisfied and some performance measures are optimised. A majority of the recent studies in ALB-E assume that any assembly task can be assigned to any workstation. This assumption lead to higher usage of resource required in assembly line. This research studies assembly line balancing of Type-E problem with resource constraint (ALBE-RC) for a single-model. In this work, three objective functions are considered, i.e. minimise number of workstation, cycle time and number of resources. In this paper, an Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) has been proposed to optimise the problem. Six benchmark problems have been used to test the optimisation algorithm and the results are compared to multi-objective genetic algorithm (MOGA) and hybrid genetic algorithm (HGA). From the computational test, it was found NSGA-II has the ability to explore search space, has better accuracy of solution and also has a uniformly spaced solution. In future, a research to improve the solution accuracy is proposed to enhance the performance of the algorithm.

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