Ljubisa Papic

Sources of fuzziness in vehicle maintenance management

Deals with sources of fuzziness in individual parts and stages of maintenance and utilization of vehicles in large fleets. Effective vehicle fleet maintenance management requires data on reliability and maintainability. In most cases, however, available data are insuffucient for proper statistical identification of performance, making it impossible to define an adequate model to support decision‐making procedures. Demonstrates that, in such cases, the fuzzy set theory is convenient for modelling these processes so as to enable decision making and maintenance management.

INTEGRATION OF BLACK-BOX AND WHITE-BOX MODELING APPROACHES FOR SOFTWARE RELIABILITY ESTIMATION

Quality of a software product should be tracked during the software lifecycle right from the architectural phase to its operational phase. Heterogeneous systems consist of several globally distributed components, thus rendering their reliability evaluation more complex with respect to the conventional methods. The objective of our work is to expand the evaluation process for effective reliability analysis by using both white box and black box approaches at prototype and at module/component level before the actual development. In this paper the, Black box testing is based on non-functional requirements for early quantitative analysis for the reliability estimation of the application development based on the output results of the prototype development. White box testing is based on inter-component interactions which deal with probabilistic software behavior. It uses an internal perspective of the system to design test cases based on internal structure at requirements and design phases. This paper has been applied for evolution of effective reliability quantification analysis at prototype level of a financial application case study with both non functional test data of software Development Life cycle (SDLC) phases captured from defect consolidation table in the form orthogonal defect classification as well functional requirements at requirement and design phases captured through software architectural modeling paradigms.

SAFETY BASED MAINTENANCE CONCEPT

Effective maintenance concept of the system has been developed and proposed on the basis of universal possible usages analysis of corrective, periodically preventive, predictive, proactive and safety based maintenance concepts in modern conditions. Starting from certain advantages and disadvantages of each concept, effective maintenance concept of the system was reached by balanced approach, i.e. their appropriate combination. However, it has been indicated that traditionally used systems reliability characteristics are not sufficient for complete description of their effectiveness. It was established as a reason that reliability characteristics do not indicate function disturbance level during system operation. It is suggested on new safety assess indicators adoption in system operation stage based on disturbance sequence modeling. It is very important that inappropriate maintenance concept must not put under question safety, i.e. cause system accident condition. Any accident condition would result with staff health and life threats and great economical losses through reengineering and system launch costs. Because of that safety based maintenance concept was consided in this work.

Investigation of Causes of Mining Machines Maintenance Problems

Human errors in the area of mining engineering are of critical issue that has serious concerns in safety, operation and production performance. There is a need for finding cause and effect relations with respect to the maintenance issues in order to detect, scrutinize and take necessary actions to reduce it. This paper deals with the human errors in the mining machines for the maintenance problems using fishbone cause and effect analysis. The investigation of these causes and effects are carried out during different operating conditions in typical mining industry and potential problems are assessed. There are several recommendations are provided to reduce the effect of human error so as to increase production by careful consideration of maintenance activities.

System Safety Analysis via Accident Precursors Selection

Starting from a systems-based statistical safety analysis, it has been noted that safety analysis in the period of operations is performed mainly in situations when accidents have not happened. Using the FMECA method, initial events screening (exclusion from the list of initial events whose effects are not significant) was performed. Benefits of the FMECA of excavator unit enable initial events list reduction for performing the ETA. The ETA methodology allows the determination of accident scenarios on the basis of initial events, for the excavator unit. One of the initial events represents the excavator unit’s disturbance, the so-called accident precursor. Safety control chart was created from which the worst initial event was determined. A new safety assessment adoption in system operation stage based on the disturbance sequence (accident scenario) modeling is proposed.

Maintenance-oriented safety control charts

A new safety based maintenance concept suggested in the paper. Starting from systems statistical safety analysis, considered step by step, it has been denoted that safety analysis in the period operation is performed mainly in situations when accident has never been happened. Using FMECA method was performed initial events screening (exclusion from the list of initial events whose effects are not significant). Benefits of FMECA of excavator unit maintenance enable initial events list reduction for performing the ETA. ETA methodology allows the determination of accident scenarios on the base of initial events, for the excavator unit. One initial event of them represents excavator unit’s disturbance—accident precursor. Safety control chart was created from where determined worst initial event. It is suggested on new safety assess adoption in systems operation stage based on disturbance sequence (accident scenario) modeling.

Software Reliability Modeling with Impact of Beta Testing on Release Decision

Increased dependence of humans on technologies has made it necessary for developing the software with high reliability and quality. This has led to an increased interest of firms toward the development of software with high level of efficiency; which can be achieved by incorporating beta tests for improving and ensuring that the software is safe and completely free from errors. In a software release life cycle, beta testing is the last important step that software developers carry out before they launch new software. Beta testing is a unique testing process that helps software developers to test a software product in different environments before its final release in the market. In this chapter of the book, we develop a SRGM by inculcating the concept of beta testing in the fault removal process to account for situations that might occur when the software is used in diverse environments. This is done to evade the chances of system being failed in the field. Conducting beta tests results in enhancement of software reliability and has been widely acknowledged. Furthermore, we have developed an optimal scheduling model and showed the importance of beta test while determining the general availability time of the software and making the system more cost effective. For validating the accuracy and predictive capability of the proposed model, we analyzed it on real software data set.

Implementation of Six Sigma Methodology in Syrian Pharmaceutical Companies

The increased competition in the global pharmaceutical market and the necessity to reach higher levels of quality of the pharmaceutical products force manufacturers to seek and adopt more effective and reliable quality management methods and techniques which allow them to introduce products with the highest possible quality level and reduced quality costs, while maintaining conformance to the pharmaceutical GMPs, technical and legislative requirements. One of the popular modern quality management methodologies is Six Sigma, which proved its high ability to increase business profits and competitiveness within more than 30 years of implementation in manufacturing and service sectors. Recently, Six Sigma methodology has been adopted by global pharmaceutical companies such as Baxter, Eli Lilly, Johnson & Johnson and Novartis and obtained considerable benefits from its abilities. This research aims at investigating the possibility to implement Six Sigma methodology in the Syrian pharmaceutical companies, and to find out what benefits a pharmaceutical company can get through the implementation of this methodology. We conducted a case study in a pharmaceutical company in Syria (Orient Pharma) in order to examine the effectiveness and advantages of Six Sigma methodology. For this purpose, a quality improvement project was conducted using DMAIC roadmap to enhance the quality for one of the main products of the company. The obtained results of DMAIC project showed an enhanced process capability, an enhanced process Sigma level, decreased variability in the process outputs. The main difficulties that have been observed during the study are resistance to change, lack of training, lack of necessary resources, attitude toward quality in the company. As a conclusion, considerable benefits can be obtained through implementing Six Sigma methodology in the Syrian pharmaceutical companies.

Methods of Modern Aircraft Structural Health Monitoring and Diagnostics of Technical State

This chapter provides an overview of the most relevant methods for monitoring the integrity of structures made of isotropic (metals and alloys) and anisotropic (polymer composite) materials, which are widely used in the manufacture of parts and construction structures in the modern industry. Special attention is paid to ensuring the safe operation of aircraft structures, the use of onboard monitoring systems which will allow to reduce economic costs in the near future and to increase flying safety. The paper describes different variants of implementation of the onboard recording systems of data in the analysis of the actual state of the elements of the air frame. The advantages are shown, due to which the construction monitoring will be able to replace the existing system of provision and supporting of the airworthiness, implemented through periodic inspections.

Development of the Standardization System in an Organization

This paper discusses the issue of standardization. It has been stated that the present theoretical state of standardization studies does not meet the requirements of the companies operating in inno...