Integration Of Fuzzy Logic Control Into Continuous Passive Motion Machines

Thirty-five years ago, a method for approaching classes of problems having a continuum of grades of membership was developed by Zadeh (1965).  Although Zadeh recognized the potential use of this fuzzy logic-based method within the medical profession, its current use in this field has been limited when compared to other scientific disciplines (Steimann, 1997).  This paper builds on the existing literature in the medical discipline by applying fuzzy logic to a particular sub-discipline: physical therapy.  More specifically, this paper presents a fuzzy logic inference engine that controls a continuous passive motion (CPM) device for use with Total Knee Arthroplasty (TKA) patients post surgery

La borrosidad como epistemología de la interacción social: algunos alcances y potencialidades

Comunicació presentada al "1er Congreso de Doctorandos/as en Psicología Social", Bellaterra del 8 al 11 de febrer de 2000.En este trabajo se describen la teoría de los conjuntos borrosos de L. A. Zadeh (antecedentes, características e implicaciones) y las áreas en las que se ha aplicado la borrosidad en psicología y psicología social (desarrollo evolutivo, procesamiento de estímulos, percepción de la información, prototipos y otras aplicaciones). A partir de esto, se sugiere cómo la borrosidad podría ser útil en el estudio de la interacción social, asumiendo el carácter simultáneamente vago y preciso de la realidad, y la utilización de conceptos como la noción de sí mismo desde una visión compleja, que considere, desde la perspectiva del pluralismo, diversas posturas teóricas y metodológicas.In this work are described the L. A. Zadeh's fuzzy set theory (its antecedents, characteristics and implications), and the areas in which the fuzziness has been used in psychology and social psychology (evolutive development, stimuli processing, information perception, prototypes and other applications). Related to this, it is suggested how fuzziness could be helpful to study social interaction -if it is assumed the reality simultaneous vague and precise character-, and the usefulness of concepts as the self notion from a complex vision, that is, considering several theoretical and methodological positions in a pluralistic perspective

A fuzzy linguistic model for the prediction of carpal tunnel syndrome risks in an occupational environment

This research presents the development and evaluation of a fuzzy linguistic model designated to predict the risk of carpal tunnel syndrome (CTS) in an occupational setting. CTS has become one of the largest problems facing ergonomists and the medical community because it is developing in epidemic proportions within the occupational environment. In addition, practitioners are interested in identifying accurate methods for evaluating the risk of CTS in an occupational setting. It is hypothesized that many factors impact an individual\u27s likelihood of developing CTS and the eventual development of CTS. This disparity in the occurrence of CTS for workers with similar backgrounds and work activities has confused researchers and has been a stumbling block in the development of a model for widespread use in evaluating the development of CTS. Thus this research is an attempt to develop a method that can be used to predict the likelihood of CTS risk in a variety of environments. The intent is that this model will be applied eventually in an occupational setting, thus model development was focused on a method that provided a usable interface and the desired system inputs can also be obtained without the benefit of a medical practitioner. The methodology involves knowledge acquisition to identify and categorize a holistic set of risk factors that include task-related, personal, and organizational categories. The determination of relative factor importance was accomplished using analytic hierarchy processing (AHP) analysis. Finally a mathematical representation of the CTS risk was accomplished by utilizing fuzzy set theory in order to quantify linguistic input parameters. An evaluation of the model including determination of sensitivity and specificity is conducted and the results of the model indicate that the results are fairly accurate and this method has the potential for widespread use. A significant aspect of this research is the comparison of this technique to other methods for assessing presence of CTS. The results of this evaluation technique are compared with more traditional methods for assessing the presence of CTS

A fuzzy linguistic model for the prediction of carpal tunnel syndrome risks in an occupational environment

This research presents the development and evaluation of a fuzzy linguistic model designated to predict the risk of carpal tunnel syndrome (CTS) in an occupational setting. CTS has become one of the largest problems facing ergonomists and the medical community because it is developing in epidemic proportions within the occupational environment. In addition, practitioners are interested in identifying accurate methods for evaluating the risk of CTS in an occupational setting. It is hypothesized that many factors impact an individual\u27s likelihood of developing CTS and the eventual development of CTS. This disparity in the occurrence of CTS for workers with similar backgrounds and work activities has confused researchers and has been a stumbling block in the development of a model for widespread use in evaluating the development of CTS. Thus this research is an attempt to develop a method that can be used to predict the likelihood of CTS risk in a variety of environments. The intent is that this model will be applied eventually in an occupational setting, thus model development was focused on a method that provided a usable interface and the desired system inputs can also be obtained without the benefit of a medical practitioner. The methodology involves knowledge acquisition to identify and categorize a holistic set of risk factors that include task-related, personal, and organizational categories. The determination of relative factor importance was accomplished using analytic hierarchy processing (AHP) analysis. Finally a mathematical representation of the CTS risk was accomplished by utilizing fuzzy set theory in order to quantify linguistic input parameters. An evaluation of the model including determination of sensitivity and specificity is conducted and the results of the model indicate that the results are fairly accurate and this method has the potential for widespread use. A significant aspect of this research is the comparison of this technique to other methods for assessing presence of CTS. The results of this evaluation technique are compared with more traditional methods for assessing the presence of CTS

Modeling and Characterization of Acute Stress under Dynamic Task Conditions

Stress can be defined as the mental, physical, and emotional response of humans to stressors encountered in their personal or professional environment. Stressors are introduced in various activities, especially those found in dynamic task conditions when multiple task requirements must be performed. Stress and stressors have been described as activators and inhibitors of human performance. The ability to manage high levels of acute stress is an important determinant of successful performance in any occupation. In situations where performance is critical, personnel must be prepared to operate successfully under hostile or extreme stress conditions; therefore training programs and engineered systems must be tailored to assist humans in fulfilling these demands. To effectively design appropriate training programs for these conditions, it is necessary to quantitatively describe stress. A series of theoretical stress models have been developed in previous research studies; however, these do not provide quantification of stress levels nor the impact on human performance. By modeling acute stress under dynamic task conditions, quantitative values for stress and its impact on performance can be assessed. Thus, this research was designed to develop a predictive model for acute stress as a function of human performance and task demand. Initially, a four factor two level experimental design (2 (Noise) x 2 (Temperature) x 2 (Time Awareness) x 2 (Workload)) was performed to identify reliable physiological, cognitive and behavioral responses to stress. Next, multivariate analysis of variance (n=108) tests were performed, which showed statistically significant differences for physiological, cognitive and behavioral responses. Finally, fuzzy set theory techniques were used to develop a comprehensive stress index model. Thus, the resulting stress index model was constructed using input on physiological, cognitive and behavioral responses to stressors as well as characteristics inherent to the type of task performed and personal factors that interact as mediators (competitiveness, motivation, coping technique and proneness to boredom). Through using this stress index model to quantify and characterize the affects of acute stress on human performance, these research findings can inform proper training protocols and help to redesign tasks and working conditions that are prone to create levels of acute stress that adversely affect human performance

Occupational Lower Extremity Risk Assessment Modeling

Introduction: Lower extremity (LE) work-related musculoskeletal disorders (WMSDs) are known to occur with cumulative exposure to occupational and personal risks. The objective of this dissertation study was to find if creating a quantifiable risk detection model for the LE was feasible. The primary product of the literature review conducted for this study resulted in focusing the attention of the model development process onto creating the initial model of the LE for assessing knee disorder risk factors. Literature Review: LE occupational disorders affect numerous industries and thousands of people each year by affecting any one of the musculoskeletal systems deemed susceptible by the occupational and personal risk factors involved. Industries known to be affected tend to have labor intensive job descriptions. Some of the numerous industry examples include mining, manufacturing, firefighting, and carpet laying. Types of WMSDs noticed by the literature include bursitis, osteoarthritis, stress fractures, tissue inflammation, and nerve entrapment. In addition to the occupationally related disorders that may develop, occupationally related discomforts were also taken into consideration by this study. Generally, both the disorders and the discomforts can be traced to either a personal or occupational risk factor or both. Personal risk factors noted by the literature include a person\u27s physical fitness and health history (such as past injuries). Meanwhile, occupational risks can be generalized to physical postures, activities, and even joint angles. Prevalence data over a three year interval (2003-2005) has found that LE WMSDs make up on average approximately 7.5% of all the WMSD cases reported to the US Occupational Safety and Health Administration (OSHA). When the literature is refined to the information pertaining to occupational knee disorders, the mean prevalence percentage of the same three year range is about 5%. Mean cost for knee injuries were found to be $18,495 (for the year between 2003 and 2004). Methodology: Developing a risk model for the knee meant using groups of subject matter experts for model development and task hazard analysis. Sample occupational risk data also needed to be gathered for each of a series of tasks so that the model could be validated. These sample data were collected from a sample aircraft assembly plant of a US aerospace manufacturer. Results: Based on the disorder and risk data found in the literature, a knee risk assessment model was developed to utilize observational, questionnaire, and direct measure data collection methods. The final version of this study\u27s knee model has an inventory of 11 risk factors (8 occupational and 3 personal) each with varying degrees of risk exposure thresholds (e.g., high risk, moderate risk, or minimal risk). For the occupational risk assessment portion of the model, the results of task evaluations include both an occupational risk resultant score (risk score) and a task risk level (safe or hazardous). This set of results is also available for a cumulative (whole day) assessment. The personal risk assessment portion only produces a risk resultant score. Validation of the knee risk model reveals statistically (t (34) = 1.512, p = 0.156), that it is functioning as it should and can decide between hazardous and safe tasks. Additionally, the model is also capable of analyzing tasks as a series of cumulative daily events and providing an occupational and personal risk overview for individuals. Conclusion: While the model proved to be functional to the given sample site and hypothetical situations, further studies are needed outside of the aerospace manufacturing environment to continue testing both the model\u27s validity and applicability to other industrial environments. The iterative adjustments generated for the occupational risk portion of the model (to reduce false positives and negatives) will need additional studies that will further evaluate professional human judgment of knee risk against this model\u27s results. Future investigations must also make subject matter experts aware of the minimal risk levels of this knee risk assessment model so that task observational results are equally comparable. Additional studies are moreover needed to assess the intimate nature between variable interactions; especially multiple model defined minimal risks within a single task

Fuzzy cognitive map modelling the adoption of educational software in schools

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis focuses on modelling factors in the adoption of educational software in schools based on the perceptions of key stakeholders. Findings indicate educational software adoption in UK secondary schools is unsatisfactory. Given the potential of educational software to affect the learning process; the government's emphasis on developing software content for learning purposes and the concern that scarce resources in schools are wasted on software that is inappropriately used or not used at all, there is a need to ensure the successful take-up of educational software. This study aims to provide schools the means to facilitate better management of resources and achieve greater utilisation of educational software. The study in recognising the importance of stakeholders in any technological adoption considers modelling educational software adoption in schools, based on key stakeholders' perceptions. Fuzzy cognitive maps (FCMs), considered extensions of cognitive maps used for modelling complex chains of casual relationships, are used as a modelling approach in this study. A mixed methods research approach is adopted. Participants, include students; a range of teachers; ICTCoordinators and ICT-Technicians, drawn from three UK secondary schools. The resulting FCM model offers a visual medium providing insight into the factors required in the take-up of educational software. Some factors identified include the availability and accessibility to IT facilities and equipment; the availability of educational software; software ability to satisfy learning requirements and to meet curriculum requirements. The model provides the means to identify factors which have a greater impact on educational software adoption, so scarce resources can be directed accordingly. As a holistic model it provides insight into the context of educational software adoption in schools. As a dynamic model it allows the opportunity to explore `what-if possibilities relating to policy and investment options. The model can act as a guide for planners, decision-makers and software developers

Fuzzy cognitive map modelling the adoption of educational software in schools

This thesis focuses on modelling factors in the adoption of educational software in schools based on the perceptions of key stakeholders. Findings indicate educational software adoption in UK secondary schools is unsatisfactory. Given the potential of educational software to affect the learning process; the government's emphasis on developing software content for learning purposes and the concern that scarce resources in schools are wasted on software that is inappropriately used or not used at all, there is a need to ensure the successful take-up of educational software. This study aims to provide schools the means to facilitate better management of resources and achieve greater utilisation of educational software. The study in recognising the importance of stakeholders in any technological adoption considers modelling educational software adoption in schools, based on key stakeholders' perceptions. Fuzzy cognitive maps (FCMs), considered extensions of cognitive maps used for modelling complex chains of casual relationships, are used as a modelling approach in this study. A mixed methods research approach is adopted. Participants, include students; a range of teachers; ICTCoordinators and ICT-Technicians, drawn from three UK secondary schools. The resulting FCM model offers a visual medium providing insight into the factors required in the take-up of educational software. Some factors identified include the availability and accessibility to IT facilities and equipment; the availability of educational software; software ability to satisfy learning requirements and to meet curriculum requirements. The model provides the means to identify factors which have a greater impact on educational software adoption, so scarce resources can be directed accordingly. As a holistic model it provides insight into the context of educational software adoption in schools. As a dynamic model it allows the opportunity to explore `what-if possibilities relating to policy and investment options. The model can act as a guide for planners, decision-makers and software developers.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A fuzzy linguistic model for the prediction of carpal tunnel syndrome risks in an occupational environment (Reprinted from Ergonomics, vol 40, pg 790-799, 1997)

This research presents the development and evaluation of a fuzzy linguistic model designated to predict the risk of carpal tunnel syndrome (CTS) in an occupational setting. CTS has become one of the largest problems facing ergonomists and the medical community because it is developing in epidemic proportions within the occupational environment. In addition, practitioners are interested in identifying accurate methods for evaluating the risk of CTS in an occupational setting. It is hypothesized that many factors impact an individual\u27s likelihood of developing CTS and the eventual development of CTS. This disparity in the occurrence of CTS for workers with similar backgrounds and work activities has confused researchers and has been a stumbling block in the development of a model for widespread use in evaluating the development of CTS. Thus this research is an attempt to develop a method that can be used to predict the likelihood of CTS risk in a variety of environments. The intent is that this model will be applied eventually in an occupational setting, thus model development was focused on a method that provided a usable interface and the desired system inputs can also be obtained without the benefit of a medical practitioner. The methodology involves knowledge acquisition to identify and categorize a holistic set of risk factors that include task-related, personal, and organizational categories. The determination of relative factor importance was accomplished using analytic hierarchy processing (AHP) analysis. Finally a mathematical representation of the CTS risk was accomplished by utilizing fuzzy set theory in order to quantify linguistic input parameters. An evaluation of the model including determination of sensitivity and specificity is conducted and the results of the model indicate that the results are fairly accurate and this method has the potential for widespread use. A significant aspect of this research is the comparison of this technique to other methods for assessing presence of CTS. The results of this evaluation technique are compared with more traditional methods for assessing the presence of CTS