A fuzzy expert system for optimizing parameters and predicting performance measures in hard-milling process

The main focus of research in hard-milling domain has been the enhancement of tool life and the improvement in workpiece surface quality. This paper deals with the application of expert system technology in order to use the experimental data for optimization of milling parameters so as to achieve targets of enhancing tool life and improving workpiece surface finish. Hard-milling experiments were conducted to study the effects of workpiece material hardness, cutter’s helix angle, milling orientation and coolant upon tool life, workpiece surface roughness, and cutting forces. The experimental data were converted to useful information using ANOVA and numeric optimization, and this information was used to develop the knowledge-base in form of IF–THEN rules. Expert system utilized fuzzy logic for its reasoning mechanism, while, fuzzy data sets and crisp sets were freely mixed in antecedents and consequents of the rules. Effectiveness of the expert system was based upon two modules, namely optimization module and prediction module, with each of them operating upon different set of rules. Optimization module provides the optimal selection and combination of aforementioned milling parameters according to the desired objective, while the prediction module provides the prediction of performance measures for the combination of parameters finalized by the optimization module.     

Analysis of assembly operations difficulty: a fuzzy expert system approach

Typical mechanical products can be assembled in various sequences of assembly operations. These sequences have high impact on the assembly time, machine utilization and even on the product quality. In order to select the best sequence of assembly operations, proper evaluation of the various sequences of assembly operations is required. This, in turn, requires the consistent evaluation of each assembly operation in the sequence. The assembly operations can be evaluated for various criteria, of which the operation difficulty is the most meaningful. This paper describes a methodology to analyse the assembly operations and calculates an operation's degree of difficulty using an expert system. This analysis consists of two steps: the first one identifies the main parameters that affect the assembly difficulty and assigns fuzzy triangular values to these parameters. The second step assigns weights to the parameters in order to maximize the agreement with a domain expert. The expert system analyses the difficulty of the assembly operation performed in two orientations: horizontal and vertical. The expert system then assigns a triangular fuzzy number as the aggregate measure of the operation's difficulty.     

Environmental ergonomics: a review of principles, methods and models

A review of the principles, methods and models used in environmental ergonomics is provided in terms of the effects of heat and cold, vibration, noise and light on the health, comfort and performance of people. Environmental ergonomics is an integral part of the discipline of ergonomics and should be viewed and practised from that perspective. Humans do not respond to the environment in a way monotonically related to direct measures of the physical environment. There are human characteristics which determine human sensitivities and responses. Practical methods for assessing responses to individual environmental components are presented as well as responses to ‘total’ environments and current and proposed International Standards concerned with the ergonomics of the physical environment.     

The role of the New Zealand forest industry injury surveillance system in a strategic ergonomics,safety and health research programme

Forestry is among the most hazardous of all industry sectors internationally. In New Zealand, highest work-related morbidity and mortality incidence rates are found in the logging sector. The New Zealand Forest Industry Accident Reporting Scheme (ARS) is a forestry injury surveillance system maintained by the Centre for Human Factors and Ergonomics (COHFE). The paper highlights the pivotal role of an industry-wide injury surveillance system in an industry-specific strategic research programme, giving examples of the use of ARS data in identification of priority areas for ergonomics, safety and health research attention, for safety awareness feedback to the industry, and in the evaluation of injury countermeasures. An analysis of injury patterns and trends for one high-risk forestry operation (skid work) is presented to illustrate both the capabilities and limitations of the ARS in its present stage of development.     

Good reasons for high variability (low inter-rater reliability) in performance assessment: Toward a fuzzy logic model

Regular performance assessment is an integral part of (high-) risk industries. Past research shows, however, that in many fields, inter-rater reliabilities tend to be moderate to low. This study was designed to investigate the variability of performance assessment in a naturalistic setting in aviation. A modified think-aloud protocol was used as research design to investigate the reasoning pairs of pilots use to assess the performance of an airline captain in a high-risk situation. Standard protocol analysis and interaction analysis methods were employed in the analysis of transcribed verbal protocols. The analyses confirm high variability in performance assessment and reveal the good, albeit fuzzy, justifications that assessor pairs use to ground their assessments. A fuzzy logic model exhibits a good approximation between predicted and actual ratings. Implications for the practice of performance assessment are provided.     

LUBRES: An expert system development and implementation for real-time fault diagnosis of a lubricating oil refining process

An expert system LUBRES (LUBricating oil Refining Expert System) is introduced in this paper. It helps plant operators in monitoring and diagnosing of abnormal situations in refining process of lubricating oil. The LUBRES structure, the knowledge base, and the inference machine are presented in detail. A new strategy is proposed for conflicts resolution – the sorting strategy of antecedents, and a selection strategy of knowledge rules in the memory knowledge base. Knowledge acquisition mechanism is based on an empirical knowledge table, while knowledge verification is carried out based on the directed graph approach. C++Builder and SQL Server 2000 have been used in developing the proposed system. LUBRES has been successfully implemented in Microsoft Windows Server environment. For 1 year, LUBRES has been used for monitoring and diagnosing of refining process of the lubricating oil. The industrial application of LUBRES proved its high reliability and accuracy.     

RFuzzy: Syntax, semantics and implementation details of a simple and expressive fuzzy tool over Prolog

We present the RFuzzy framework, a Prolog-based tool for representing and reasoning with fuzzy information. The advantages of our framework in comparison to previous tools along this line of research are its easy, user-friendly syntax, and its expressivity through the availability of default values and types.In this approach we describe the formal syntax, the operational semantics and the declarative semantics of RFuzzy (based on a lattice). A least model semantics, a least fixpoint semantics and an operational semantics are introduced and their equivalence is proven. We provide a real implementation that is free and available. (It can be downloaded from http://babel.ls.fi.upm.es/software/rfuzzy/.) Besides implementation details, we also discuss some actual applications using RFuzzy.     

The effects of occupational health and safety management on work environment and health: a prospective study

According to Norway's Internal Control Regulation, all companies are required to have an occupational health and safety (H&S) management system. This study investigated the effects of implementing or improving occupational H&S management on the work environment, H&S-related behaviour and musculoskeletal health of workers in small and medium-sized companies. A one-year prospective cohort study, using self-administered questionnaires, was performed among the managers and blue-collar workers in 226 motor vehicle repair garages. Out of 1559 workers that responded at baseline 721 workers could be identified at follow-up. These 721 workers were included in the study. The workers in companies with improved H&S management from baseline to follow-up reported increased satisfaction with the H&S activities at the garage; improved support from management and colleagues; improved health-related support and control; and increased participation in H&S activities.     

An adaptive network-based fuzzy inference system (ANFIS) for the forecasting: The case of close price indices

The close price prediction model of the Zagreb Stock Exchange Crobex® index is presented in this paper. For the input/output data plan modeling the Crobex® index close price historical data are retrieved from the Zagreb Stock Exchange official internet pages. The prediction model is created in the way that for each of 5 days in advance it predicts the Crobex® close price. The prediction model is generated based on the input/output data plan by means of the adaptive neuro-fuzzy inference system method, representing the fuzzy inference system. It is of the essence to point out that for each day a separate fuzzy inference system is created by means of the adaptive neuro-fuzzy inference system method based on the same set of input/output data, the only difference being that for every separate fuzzy inference system different subsets for training and checking are used so that input variables are differently created. The input/output data set represents the historical data of the Crobex® index close price from 4 November 2010 to 24 January 2012 and the Crobex® index close price is predicted for the subsequent 5 days, the first day of prediction being 25 January 2012. After that the above mentioned input/output data set is shifted 5 days in advance and the Crobex® index close price is predicted in advance for the next 5 days starting with the last day of the input/output data set. In that way the Crobex® index close prices are predicted until 19 October 2012 based on the Crobex® index close price historical data. At the end of the paper qualitative and quantitative estimates are presented for the given approach of predicting the Crobex® index close price showing that the approach is useful for predicting within its limits.     

某基地设备综合监控系统网络通讯设计与实现

针对现场现有的监控系统各自封闭,并不兼容的现状,提出了综合监控系统网络通讯方案,构建了集环境温湿度监控、设备监控、变电站监控和风水监控一体的综合监控系统。实际的运行效果证明,该系统设计合理,具有良好的可靠性和实用性。     

A fuzzy inference system for pump failure diagnosis to improve maintenance process: The case of a petrochemical industry

Pump operating problems may be either hydraulic or mechanical and there is interdependence between the failure diagnoses of these two categories. Consequently, a correct diagnosis of a pump failure needs to consider many symptoms and hydraulic or mechanical causes. But, due to nonlinear, time-varying behavior and imprecise measurement information of the systems it is difficult to deal with pumps failures with precise mathematical equations, while human operators with the aid of their practical experience can handle these complex situations, with only a set of imprecise linguistic if-then rules and imprecise system state, but this procedure is time consuming and needs the knowledge of human experts and experienced maintenance personnel. The purpose of this study is to provide a correct and timely diagnosis mechanism of pump failures by knowledge acquisition through a fuzzy rule-based inference system which could approximate human reasoning. The proposed fuzzy inference system by: (1) reduction of human error, (2) reduction of repair time (3) creation of expert knowledge which could be used for training (4) reduction of unnecessary expenditures for upgrades and finally, (5) reduction of maintenance costs, will improve the maintenance process. The novelty of this work is the knowledge acquisition (the extraction of linguistic rules) through the interactive impact of the critical failure modes on the both hydraulic and mechanical operating parameters including flow rate, discharge pressure, NPSHR (Net Positive Suction Head Required), BHP (Brake Horse Power), efficiency, vibration and temperature. The proposed approach is tested and applied to a petrochemical industry.     

Proposing a new integrated model based on sustainability balanced scorecard (SBSC) and MCDM approaches by using linguistic variables for the performance evaluation of oil producing companies

Using the balanced scorecard approach based on sustainable development parameters is a powerful and useful methodology to evaluate the sustainable performance of organization or company. In this paper, a new approach based on sustainability balanced scorecard (SBSC) and multi criteria decision making (MCDM) approaches is developed for evaluating the performance of oil producing companies in Iran. For reflecting the interdependent relationships among factors influencing the problem under consideration, analytical network process (ANP), a branch of the MCDM techniques, is employed. However, using the ANP method for calculating the preference ratings of alternatives is a time-consuming and bothersome process; therefore, COPRAS (COmplex PRoportional ASsessment) technique is adopted to prioritize the feasible alternatives in terms of linguistic variables. Based on this study, the results demonstrate the effectiveness of the proposed model. The performance evaluation model proposed by using a combination of the MCDM methods and the SBSC approach helps authorities to make an attempt for achieving a competitive advantage.     

Analysis, design, and development model: a case study of an internet-based system for insert and parameter selection

Abstract. The analysis, design, and development model (ADDM) is based on the systems lifecycle process (SLCP) in which analysts begin to understand external client requirements and internal client specifications as they are designing and developing a complex system. In the ADDM, clients and system analysts (SA) continuously interact as the system is being designed, developed, tested and maintained. In the design phase, system development can be altered when it is most cost‐effective. Depending on the type of environment and SA preference and expertise, various interfaces and software and hardware configurations are created during the SLCP. The SLCP ensures effective standardization and continuous quality improvements throughout development. The model follows modern information technology principles to integrate and monitor SLCP phases. A case is presented that describes an application of the ADDM. This case outlines the architecture of an e‐commerce production system (ECPS). The system has a three‐tier structure consisting of the client interface, Java server page (JSP) and database module. The model assists in designing economic production operations in an industrial setting by allowing a client to retrieve current production data needed for operations through the internet.     

Path-based approach to integrated planning and control for robotic systems: A path-based approach provides an analytical integration of robot planning and control. As a result, the task level control can be achieved, and the system is capable of coping with unexpected or uncertain events

Our newly developed event-based planning and control theory is applied to robotic systems. It Introduces a suitable action or motion reference variable other than time, but directly related to the desired and measurable systems output, called event. Here the event is the length of the path tracked by a robot. It enables the construction of an integrated planning and control system where planning becomes a real-time closed-loop process. The path-based integration planning and control scheme is exemplified by a single-arm tracking problem. Time and energy optimal motion plans combined with nonlinear feedback control are derived in closed form. To the best of our knowledge, this closed-form solution was not obtained before. The equivalence of path-based and time-based representations of nonlinear feedback control is shown, and an overall system stability criterion has also been obtained. The application of event-based integrated planning and control provides the robotic systems the capability to cope with unexpected and uncertain events in real time, without the need for replanning. The theoretical results are illustrated and verified by experiments.