Miroljub Grozdanovic

Usage of Human Reliability Quantification Methods

Human reliability quantification (HRQ) methods are becoming increasingly important in risk and accident assessment in systems these terms are usually related to (hi-tech industrial systems, including nuclear and chemical plants). These methods began to intensively develop after numerous accidents caused by human error or inadequate activity of people who controlled and managed complex technological processes. For already existing systems, but also for new ones, it is important to assess the possibility of an accident. Determination of possible preventive activities, which include the influence of human error on the safety of a system, is also required. These are the main goals of the HRQ method. Using Absolute Probability Judgment (APJ) and Success Likelihood Index Methods (SLIM) HRQ techniques in control and management centers in electro-power systems in Belgrade and railway traffic in Nis (both in Serbia and Montenegro) are shown in this paper.

The selection of the key ergonomic indicators influencing work efficiency in railway control rooms

This paper presents an analytical–synthetic model of ergonomic research of the abilities of the dispatcher/operator in the control room for the automatic control of railway transportation. Twenty performance indicators describing the operators’ performance (work capacity and perceptive abilities) and the main characteristics of the control room (work organization and ergo-technical analysis) are identified. A group fuzzy analytic hierarchy process is applied in the process of ranking and selection of key performance indicators of railway control rooms. The selected key performance indicators (the operator’s hand movement, visual symptoms of fatigue, device error analysis, location and dimensions of the control desk) are analysed in detail.

Assessment of the key factors for ergonomic design of management information systems in coal mines

Using an analytic-synthetic model of ergonomic research of management information systems (MIS) in coal mines, we identified 13 elements which were used to define eight factors that impact operator’s performance. These eight factors were further reduced to five key factors after the application of expert assessment. We have defined 23 indicators for these key factors, ranked by means of the analytic hierarchy process method. This paper includes a detailed ergonomic analysis of the five key operator quality indicators, namely, shape and size of the control panel, functionality of the video display terminal, keyboard functionality, alarm response time and expansion of the MIS with environmental parameters. Based on the condition prior to and after the proposed changes, we were able to use this approach to determine and discuss the operator quality index.

The impact of character/background colour combinations and exposition on character legibility and readability on video display units

This paper presents the impact of text and background colour combinations on the legibility of characters and readability of text presented on video display units (VDUs). The stimulus features influencing the operator’s response latency and accuracy are analysed in two experiments, examining the effects of text–background colour combinations and stimulus exposition on the ability of character and word identification on VDUs. This is analysed for the purpose of improving the information presentation in control information systems in Serbian underground coal mines. The legibility of characters based on the main colour combinations was tested by focusing on 30 participants. The first experiment required the participants to identify the legibility of uppercase alphabetic characters and numbers randomly selected and presented on a VDU. The visual performance was expressed by the number of correctly identified characters. The second experiment required the participants to identify the readability of the presented characters, based on the colour combinations of the characters and the background, in order to identify the best possible combination of colours for fast identification of information, which is very important in the detection of fast-changing unwanted events. The results of the experiments suggested that the character recognition was strongly influenced by character/background colour combination and exposition. The adequate selection of these variables can significantly improve the legibility of characters, and improve the speed and the accuracy of the identification of potential problems in underground coal mines during emergency situations.

Development and Application of a Decision Support System for Human Reliability Assessment – A Case Study of an Electric Power Company

This paper describes the human reliability assessment using absolute probability judgment (APJ) method in the Electric Power Company of Serbia (EPS). Taking into account conventional APJ approach, a new decision support tool EPS-APJ was developed. The EPS-APJ tool is intended for use by a group of experts for human error probability assessment. The basic goal of the tool is to facilitate the process of decision-making by experts, in the complex environment of the electric power companies. The usefulness of this new tool is approved in a case study of use of the EPS-APJ for the purpose of the analysis of a repair intervention on a 10/0.4-kV steel lattice tower ‘Nogaje’, in the EPS. For the purpose of this study, a database on work-related injuries, accidents, and critical interventions occurred over a 10-year period was created. The research comprised analysis of 1074 workplaces, with the total of 3997 employees. The case study performed at the EPS has confirmed that the EPS-APJ tool for quantification of human errors is highly applicable, comprehensive, and simple to use. Comparison of the results obtained by application of the EPS-APJ tool versus the basic APJ method has confirmed the accuracy of the decision support tool, and significant speed advantage in conducting an expert evaluation. Copyright

Data Acquisition and Remote Control Systems in Coal Mines: A Serbian Experience

The paper presents the development and application of measurement and control devices and control information systems in coal mines with underground exploitation. The locations of units for measuring the concentration of methane, carbon monoxide and oxygen; the control of short circuits on ventilation doors; the control of main fan depression and the airflow speed are proposed. As a result of the research, the structure of control information system in Senje mine and ergonomic analysis of measurement and control devices in this mine are presented. Further modes of development of control information systems in underground mines in Serbia and solutions for their reconstruction are proposed.

The Role of Human Error Analysis in Occupational and Environmental Risk Assessment: A Serbian Experience

ABSTRACT Human error analysis is certainly a challenge today for all involved in safety and environmental risk assessment. The risk assessment process should not ignore the role of humans in accidental events and the consequences that may derive from human error. This article presents a case study of the Success Likelihood Index Method (SLIM) applied to the Electric Power Company of Serbia (EPCS), with the aim to disclose the importance of human error analysis in risk assessment. A database on work-related injuries, accidents, and critical interventions that occurred over a 10-year period in the EPCS provided the basis for this study. The research comprised analysis of 1074 workplaces, with a total of 3997 employees. A detailed analysis identified 10 typical human errors, performance shaping factors (PSFs), and estimated human error probability (HEP). Based on the obtained research results one can conclude that PSF control remains crucial for human error reduction, and thus prevention of occupational injuries and fatalities (the number of injuries decreased from 58 in 2012 to 44 in 2013, no fatalities recorded). Furthermore, the case study performed at the EPCS confirmed that the SLIM is highly applicable for quantification of human errors, comprehensive, and easy to perform.

The development of a new integral control model based on the analysis of three complex systems in Serbia

Abstract The aim of this paper is to analyse the results of research carried out in the railway, mining, and electric power systems in Serbia and form a new integral control model. The three methodological procedures are applied. First, analytical-synthetic methodological approach breaks down complex technical system into three parts: bio-cybernetic system, “operator”; technical system, “technology”; and additional system, “working environment.” Second, network planning method is used to analyse time, according to the critical path method. Third, fuzzy analytic hierarchy process determines the key research factors. General results of research are new integral control model, and new research areas and activities. The most prominent factors are: in “bio-cybernetic system”—operator’s arm reach, body postures and movement sequences, operator’s work, occurrence of stress, and occurrence of fatigue; in “technical system”—location and dimension of control desk, display panel, video display terminal, symbols on video display terminal, colours in control centres, and suitability of the keyboards; and in “supporting system”—illumination in control centres and relative humidity. Based on the analysis of factors and synthesis of results, the following recommendation are proposed: new control desk design; new display panel design; new design of the main and local lighting; new illumination and contrast characteristics, and environmental impact assessment. For research on a variety of complex technical systems, new integral control model can be applied, with corresponding extensions.

Research on Key Indicators in Modern Surgical Practice Assessment: Ergonomic Approach:

It is undeniable that fundamental requirements in surgery refer to the adequate use of medical knowledge (eg, clinical knowledge and technical skills). However, this knowledge and skills of surgeons should be supplemented with synergetic research of capabilities of surgeons, operating rooms (ORs), and nontechnical skills. In this article, by using expert research, we presented 15 key indicators in surgical practice assessment. Communication efficiency in the OR has been ranked as the first and most important among indicators using the fuzzy analytic hierarchy process method. Within the analysis of this indicator, we have shown a new method that provided us with the results describing the extent of communication, the correlation in the communication system, surgeon workload uniformity, and isolation of individual surgeons in the OR. The goal of this research is aimed at the increase of operator efficiency in the OR. It is necessary that results of this kind of research find their practical use and become an obligatory element in the construction of new ORs as well as reconstruction of old ORs.

The key risk indicators of road traffic crashes in Serbia, Niš region

ABSTRACT Traffic crashes are a serious public health and socio-economic problem, and they are one of leading causes of death of males in Serbia. In order to determine the main causes of road traffic crashes in Niš region, Republic of Serbia, nine key risk indicators of road traffic crashes are identified, organized into four groups (number and structure of crashes, consequences of traffic crashes, temporal and spatial location of traffic crashes, causes and sanctions), and described in detail. The indicators are ranked based on group fuzzy analytic hierarchy process (AHP), where experts from insurance companies, professionally engaged in the process of risk assessment, with different previous experience present different impact on the final ranking. In relation to the most influential factors in the assessment of traffic crashes, improper and unadjusted vehicle speed, overtaking and passing, as well as the physical condition of the driver have the highest effect.