Jozef Kováč

Methodology and Application of the Kruskal-Wallis Test

This paper describes the methodology and application of the very popular nonparametric test which is a rank based test named as Kruskal-Wallis. This test is useful as a general nonparametric test for comparing more than two independent samples. It can be used to test whether such samples come from the same distribution. This test is powerful alternative to the one-way analysis of variance. Nonparametric ANOVA has no assumption of normality of random error but the independence of random error is required. If the Kruskal-Wallis statistic is significant, the nonparametric multiple comparison tests are useful methods for further analysis. The statistical analysis of the application data in this paper was performed with software MATLAB.

Possibilities of Production Simulation in Software Product Tecnomatix – Plant Simulation at Wood Processing Example

This paper contains the description of the production process and the simulation in Plant Simulation. It also contains the description of the steps, which are necessary to create the simulation of the production process with the pictures directly from Plant Simulation.

Designing Simulation Model of the Production Operation for Further Decision Making

Simulation as a decision making method through its software is a supportive tool for analysis of a material flow, and it is appropriate when a performance of complex systems have to be evaluated, designed and optimized. As the behavior of complex systems is hardly predictable, simulating the existing systems’ performance is helpful in order to gain results of system performance before applying changes in a real system. A change that appears to be a best solution might, after calculation and analysis of its consequences, prove as a wrong direction lead. The more accurately is the model built, the more real results are being achieved. Decisions about the performance improvement might be intuitive as what-if analysis, or achieved by process redesign and improvement methods as Theory of Constraints, Lean Manufacturing, Six Sigma Method, some of them with slight changes in a single processes following Kaizen principles.

Application of Modelling and Simulation in the Selection of Production Lines

Production lines are complex mechatronic systems which have in their structure mechanical, electronic, control and software subsystems. The complexity of these systems is identified for mass production of paper napkins. The aim is to decide on the choice of the production line in terms of ensuring growth of value of the business and satisfaction of customers needs. The decision making process is carried out in steps of formulating the investment problem, technical features of the project, economic evaluation of the project based on a financial model in Microsoft Excel and analysis of project risks utilizing Monte Carlo simulations in the Crystal Ball system.

Processing the Experimental Data from Simulation Model of the Production Operation

Experimental studies of production technological processes are now enabled through a use of the available simulation software. The scientific studies, executing experiments with simulation software, are used to optimize, improve efficiency, and elimination of deficiencies in manufacturing processes without any interfering with the real processes. The big advantage is that by using simulation software, one can simulate a number of experimental variations of scenarios in advance, and evaluate any intervention in the course of the active process. Experiments with a built simulation model answer the questions of what-if analysis for variable set scenarios.

Specific Car Manufacturer Recalls

A variety of engineering errors can cause a defect in vehicles. Problems are usually concentrated on models that were produced during a certain time period at one specific plant. Consumers who encounter such problems can report them, fill petitions or put online complaints on specific car manufacturers. Vehicle defects can cause many problems and even endanger human life. That is why, in the interest of safety, any recall affecting the consumer vehicle should be completed without delay. The paper presents recalls of three car manufacturers, namely: Volkswagen group, PSA, and Kia analyzed between years 2005 to 2015. The results are presented in graphs and diagrams. First part of the paper discusses the current terminology and procedures of car recalls. In the second part the three car manufacturers are presented. Recall analysis creates the third part of the paper and the results are presented in form of graphs and diagrams. Also the error rate of each car manufacturer is calculated and presented in the paper.

Pilot project of method quick changeover implementation in NC machining of car's clutch housing

The article referred to the practical application of the tool Quick Changeover in the framework of workshops and Lean project aimed at rebuilding NC machines for machining of cars clutch housing.

Laboratory Experiment of New Cutting Materials in Milling Processes

The development of manufacturing technology is mostly given by economics, environmental trends and the development of cutting materials and machine tools. Manufacturing is a significant part of the worldwide economy. Machining (material removal processes) represents major part of production costs. This paper yield inquiries into the hard and precise milling with a focus on force effects in experimental machining, tool wear and final surface qualities (roughness, micro hardness). The precision machining of hardened steel differs from conventional machining in terms of the hardness of the workpiece materials and the cutting tool materials that are required. Hard materials are characterized by high hardness (> 45 HRC) and abrasiveness. Machining processes require cutting tools of much higher hardness and also higher resistance of the abrasive wear. Recently developed cubic boron nitride (CBN) and coated sintered carbides cutting tools are considered to have the ability of cutting such as steel. CBN cutting tools show good performance during machining of the hardened steel because of their hot hardness and good fracture toughness.

Application of Virtual Reality Means in Dashboard Function and Dashboard Assembly Fixture Ergonomic Analysis

Manual assembly has in some areas of production dominant role. For its effective performance the different jigs and fixtures may be used. For the design of such fixtures, it is useful to use CAD systems. The proposed fixture is necessary to additionally verify from the different points of view, including the ergonomic. For the fixture verification from ergonomic point of view, it appears that it is useful to use virtual reality components such as data gloves and their connection to the CAD design. The article describes the application of data glove for the verification of the functionality of the product and the functionality of its assembly fixture from ergonomics point of view.

Logistic of Building Simulation Model of Healthcare Facility for Further Performance Management – Case Study

Logistics, as a scientific discipline, used to be oriented till lately on distribution of finished products from producer site to consumer sector, and this fact has reflected even in modeling and simulation approach. Simulation models of Healthcare Services, and generally services, can be considered as innovative procedures and till lately were not as widely described as for example typical material flow in manufacture. However, base knowledge that inheres in production simulation models can be applied at building of services simulation models.