A unique intelligent algorithm for optimization of human reliability and decision styles: a large petrochemical plant

Abstract

The importance of decision-making failures in complex systems such as petrochemical plants has been well recognized. Decision making failures are mostly resulted from human error. In this paper, efficiency of human operator is assessed based on combination of decision style (DS) and human reliability. At first, a standard questionnaire is designed to collect required data. The reliability of the collected data is investigated by Cronbach’s alpha (about 0.75). Also, the efficiency is ranked according to the impact of decision styles on human reliability factors. Operators of control rooms in a petrochemical plant are respond to a human reliability-decision styles (HR-DS) hybrid questionnaire. The indicators related to decision styles and human reliability are used as inputs and outputs, respectively in a unique adaptive network-based fuzzy inference system (ANFIS) algorithm. Decisive, hierarchical, flexible and integrated are the standard categorization of human decision styles. The optimum structure of ANFIS is selected based on minimum mean absolute percentage (MAPE). The best MAPE is achieved about 26%. Relative analysis shows that the efficient decision style achieved from ANFIS is consistent with plant’s dominant style. The results of this study help managers to enhance the system performance by using the best operator for critical positions. This study presents the first neuro-fuzzy algorithm for improvement of decision making and human reliability in a large petrochemical plant.

Appendices

Appendix 1: Questionnaire

1	The influence on system, preference in using the logical reasoning, applying creativity and innovation, implementing regulations
1.1	Can your ability to influence on the system be remedial in crisis situations?
1.2	Can logical reasoning be useful in emergency situations?
1.3	Can creativity and innovation be useful in emergency situations?
1.4	Can implementing regulations be remedial in crisis situations?
2	Time pressure, pace of work, excessive workload
2.1	What is the importance degree of time pressure when faced with an emergency situation?
2.2	What is the importance degree of pace of work when faced with an emergency situation?
2.3	What is the importance degree of excessive workload when faced with an emergency situation?
3	The need for planning, lack of awareness about the work and the regulations, control limits, rate of power
3.1	How much planning needs can be useful in emergency situations?
3.2	Can lack of awareness about the work and the regulations be effective in emergency situations?
3.3	Can the definition of control for the operator be remedial in crisis situations?
3.4	Can rate of operator’s power be effective in emergency situations?
4	Information complexity, uncertainty, rate of involvement with others
4.1	What is the importance degree of information complexity when faced with an emergency situation?
4.2	What is the importance degree of uncertainty when faced with an emergency situation?
4.3	What is the importance degree of rate of involvement with others when faced with an emergency situation?
5	Argument and logic needed to perform the assigned works
5.1	Are using reason and logic useful to perform the assigned works?
5.2	Can the arguments with others be useful to perform the assigned works?
6	Preference in using several methods, involvement of others
6.1	What is the importance degree of using several methods when faced with an emergency situation?
6.2	What is the importance degree of involvement of others when faced with an emergency situation?
7	Degree of risk
7.1	Is there the training in relation to safety issues (such as fire and explosion)?
7.2	Is there an abnormal condition in the workplace that is not provided in the instructions?
7.3	Do you have job security in your work?
7.4	Do you work in high risk condition (accident and injury)?
7.5	Do you think that in the workplace there is a risk of fire and explosion?
7.6	Is there pollution in the vicinity of your work?
8	Physical and mental health
8.1	Do you feel pain or fatigue during daily work on your waist?
8.2	Do you feel pain or fatigue after work on your waist?
8.3	Do you feel pain or fatigue during the daily work on your hands?
8.4	Do you feel pain or fatigue after the completion of work on your hands?
8.5	Do you feel pain or fatigue during daily work on your feet?
8.6	Do you feel pain or fatigue in your legs after work?
8.7	Do you feel pain or fatigue in the head and neck during daily work?
8.8	Do you feel pain or fatigue after the work in your head and neck?
8.9	Dose the breathing bother you in your workplace?
8.10	Dose the breathing bother you out of your workplace?
8.11	Dose the sound bother you in your workplace?
8.12	Dose the sound bother you out of your workplace?
8.13	Do you have sore eyes after work?
8.14	Is noise disturbed your concentrate in the workplace?
8.15	Are other activity or people disturbed your concentrate in the workplace?
8.16	Should your eyes move from the dark to light and from light to dark?
9	Communications
9.1	How do you evaluate your ease of communication with your supervisors?
9.2	Do you clearly know the available instructions?
9.3	Do you have problems with colleagues within the organization?
9.4	Can you achieve easily the required information from managers or supervisors?
9.5	Can you achieve easily the required information from colleagues?
9.6	Do the information exchange and communication with colleagues outside of organization help you in your works?
9.7	Do you perform your works without the need for constant contact with other people?
10	Inherent psychological characteristics
10.1	Do your performance at work depend on work shift?
10.2	Do changing of the work shift depend on your performance?
11	Stress factors
11.1	Should you follow the rules and regulations?
11.2	How do you evaluate the pressure working in your organization at normal situation?
11.3	How do you evaluate the pressure working in your organization at emergency situation?
11.4	Do you need to instructions due to the nature of your work in normal situations?
11.5	Do your organization provide instructions regarding work in emergency situations?
11.6	Do you need to instructions due to the nature of your work in emergency situations?
11.7	Do your manager control and monitor your works?
11.8	How do you evaluate the stress issues in your organization at normal situation?
11.9	How do you evaluate the stress issues in your organization at emergency situation?
12	Skill level
12.1	Do you feel comfortable in the use of personal protective equipment?
12.2	Are you able to find an unusual situation in your works?
12.3	Do you understand rules and regulations in your organization at emergency situation?
13	Anthropometry
13.1	If you work standing do you prefer (and possible) sitting work?
13.2	Do you think your work could design a better way (as amended), to provide more comfort and safety for you?
13.3	Can an elbow rest be designed for tour work?
13.4	Is enough space for free movement and comfort in your work?
13.5	Do you need a place to relax feet?
13.6	Is the intensity of natural light (daylight) in the control room during the day enough?
13.7	Is the intensity of natural light (daylight) in the workplace outside of the control room enough?
13.8	Is the control room lighting appropriate (especially for evening and night shifts)?
13.9	How do you evaluate the quality of natural light in your work?
13.10	Is there high brightness difference (contrast or contrast) in different parts of your work?
13.11	Is the temperature tolerable at hot season in your work?
13.12	Is cooling equipment (refrigerators) be located in the right location?
13.13	Is the temperature tolerable at cold season in your work?
13.14	Is heating equipment (refrigerators) be located in the right location?
13.15	Is it enough to breathe fresh air?
13.16	Do you drink enough liquid to compensate for sweating?
13.17	Do you think that noise reduction is applicable in the workplace?
13.18	Do you think that the tables, chairs, and equipment location can be caused risks and incident at normal situation?
13.19	Do you think that the tables, chairs, and equipment location can be caused risks and incident at emergency situation?
14	Human errors
14.1	Do you have to violation of safety regulations due to pressures of work in normal situation?
14.2	Do you have to violation of safety regulations due to pressures of work in emergency situation?
15	Job satisfaction
15.1	Are you satisfied with your salary?
15.2	Do you feel happy with your work in general?
15.3	Are you satisfied with time working?

Appendix 2: Train code

• % %train for anfis

• itrain = xlsread(‘s.xls’,’r’,’A1:d57’);

• otrain = xlsread(‘s.xls’,’r’,’n1:n57’);

• itest = xlsread(‘s.xls’,’r’,’A58:d62’);

• otest = xlsread(‘s.xls’,’r’,’n58:n62’);

• trnData = [itrain otrain];

• j = 1;

• for i = 0.1:0.01:1

• fismat = genfis2(itrain,otrain,i);

• fismat = setfis(fismat,’andmethod’,’prod’);

• fismat = setfis(fismat,’ormethod’,’max’);

• fismat = setfis(fismat,’impmethod’,’prod’);

• fismat = setfis(fismat,’aggmethod’,’sum’);

• out_fis = anfis(trnData,fismat,20);

• y(:,j) = evalfis(itest,out_fis);

• j = j+1;

• end

• for i = 1:85

• e1 = y(:,i)-otest;

• mape(i) = mean(abs(e1./otest));

• end

• xlswrite(‘prod-max-prod-sum’,mape,’mape’);

Appendix 3: Output code

• % % test for anfis

• input = xlsread(‘s.xls’,’r’,’A1:d62’);

• itrain = xlsread(‘s.xls’,’r’,’A1:d57’);

• otrain = xlsread(‘s.xls’,’r’,’e1:e57’);

• trnData = [itrain otrain];

• fismat = genfis2(itrain,otrain,0.27);

• fismat = setfis(fismat,’andmethod’,’prod’);

• fismat = setfis(fismat,’ormethod’,’max’);

• fismat = setfis(fismat,’impmethod’,’prod’);

• fismat = setfis(fismat,’aggmethod’,’sum’);

• out_fis = anfis(trnData,fismat,20);

• z = evalfis(input,out_fis);

Appendix 4: Efficiency code

• % % efficiency

• itrain = xlsread(‘s.xls’,’r’,’A1:d57’);

• otrain = xlsread(‘s.xls’,’r’,’g1:g57’);

• p = xlsread(‘s.xls’,’r’,’A1:d62’);

• t = xlsread(‘s.xls’,’r’,’g1:g62’);

• trnData = [itrain otrain];

• fismat = genfis2(itrain,otrain,0.32);

• fismat = setfis(fismat,’andmethod’,’min’);

• fismat = setfis(fismat,’ormethod’,’max’);

• fismat = setfis(fismat,’impmethod’,’prod’);

• fismat = setfis(fismat,’aggmethod’,’max’);

• out_fis = anfis(trnData,fismat,20);

• z = evalfis(p,out_fis);

• for i = 1:115

•   v(i) = mean(t)- t(i)/115;

•   s = sum(v);

•   w(i) = v(i)/s;

•   E(i) = t(i)-z(i);

•   E1(i) = E(i)/w(i);

•   [c,k] = max(E1);

•   sh(i) = E(k)*(w(i)/w(k));

•   F(i) = t(i)/(z(i) + sh(i));

• End