Simultaneous design of membership functions and rule sets for fuzzycontrollers using genetic algorithms

This paper examines the applicability of genetic algorithms (GA's) in the simultaneous design of membership functions and rule sets for fuzzy logic controllers. Previous work using genetic algorithms has focused on the development of rule sets or high performance membership functions; however, the interdependence between these two components suggests a simultaneous design procedure would be a more appropriate methodology. When GA's have been used to develop both, it has been done serially, e.g., design the membership functions and then use them in the design of the rule set. This, however, means that the membership functions were optimized for the initial rule set and not the rule set designed subsequently. GA's are fully capable of creating complete fuzzy controllers given the equations of motion of the system, eliminating the need for human input in the design loop. This new method has been applied to two problems, a cart controller and a truck controller. Beyond the development of these controllers, we also examine the design of a robust controller for the cart problem and its ability to overcome faulty rules     

IoT-Enabled Autonomous System Collaboration for Disaster-Area Management

Timely investigating post-disaster situations to locate survivors and secure hazardous sources is critical, but also very challenging and risky. Despite first responders putting their lives at risk in saving others, human-physical limits cause delays in response time, resulting in fatality and property damage. In this paper, we proposed and implemented a framework intended for creating collaboration between heterogeneous unmanned vehicles and first responders to make search and rescue operations safer and faster. The framework consists of unmanned aerial vehicles (UAVs), unmanned ground vehicles (UGVs), a cloud-based remote control station (RCS). A light-weight message queuing telemetry transport (MQTT) based communication is adopted for facilitating collaboration between autonomous systems. To effectively work under unfavorable disaster conditions, antenna tracker is developed as a tool to extend network coverage to distant areas, and mobile charging points for the UAVs are also implemented. The proposed framework’s performance is evaluated in terms of end-to-end delay and analyzed using architectural analysis and design language (AADL). Experimental measurements and simulation results show that the adopted communication protocol performs more efficiently than other conventional communication protocols, and the implemented UAV control mechanisms are functioning properly. Several scenarios are implemented to validate the overall effectiveness of the proposed framework and demonstrate possible use cases.      

Consultation as a means of veteran suicide prevention.

The development and implementation of a suicide consultation service being run by an interdisciplinary team in a metropolitan Veteran’s Administration (VA) medical center is described. This service is grounded in a collaborative theoretical framework. An overview of the consultation process and theoretical and empirical literature to support the framework used by the service are provided. Some of the interventions commonly recommended to referring clinicians to reduce client suicide risk are reviewed. Although there are many challenges to running a service such as this, the authors conclude that the model presented is flexible enough to be applied in a variety of settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Stable Analytical Solution Method for Car-Like Robot Trajectory Tracking and Optimization

In this paper, the car-like robot kinematic model trajectory tracking and control problem is revisited by exploring an optimal analytical solution which guarantees the global exponential stability of the tracking error. The problem is formulated in the form of tracking error optimization in which the quadratic errors of the position, velocity, and acceleration are minimized subject to the rear-wheel car-like robot kinematic model. The input-output linearization technique is employed to transform the nonlinear problem into a linear formulation. By using the variational approach, the analytical solution is obtained, which is guaranteed to be globally exponentially stable and is also appropriate for real-time applications. The simulation results demonstrate the validity of the proposed mechanism in generating an optimal trajectory and control inputs by evaluating the proposed method in an eight-shape tracking scenario.     

The role of “hierarchy” in the design of fuzzy logiccontrollers

This paper investigates the role of hierarchy in the systematic approach to the design of fuzzy logic controllers (FLC's). The key concept here is that the implementation of fuzzy engines at higher levels of the control hierarchy (where more reasoning is involved) yields more versatile fuzzy controllers with generally fewer control rules. At the same time, the structured nature of a hierarchical approach considerably simplifies the design procedure.     

Driving, aging, and traumatic brain injury: Integrating findings from the literature.

Objective: In order to address the potential compounded risk in the population of aging traumatic brain injury (TBI) survivors who continue to drive, the authors synthesized literatures regarding the impact of aging or TBI on driving. Study Design: PubMed searches were conducted utilizing combinations of the following terms: driving, aging, elderly, TBI, cognition, seizures, vision, hearing, rehabilitation, sleep, fatigue, and assessment. Additional sources were also identified from the bibliographies of articles obtained and the Transportation Research Information Service electronic database. Clinically relevant human studies written in English were reviewed. Results: Using a conceptual framework developed by W. H. Brouwer and F. K. Withaar (1997), the authors of the current review highlight driving-related obstacles for TBI survivors and aging adults and suggest that individuals aging with TBI may be at increased risk for driving-related problems. Implications: Areas for clinical consideration include seizures, sleepiness and fatigue, vision, cognition, driving assessment, and caregiver involvement. The need for further study of postacute driving assessment and rehabilitation is highlighted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological test performance in soldiers with blast-related mild TBI.

This exploratory study was conducted to increase understanding of neuropsychological test performance in those with blast-related mild traumatic brain injury (mTBI). The two variables of interest for their impact on test performance were presence of mTBI symptoms and history of posttraumatic stress disorder (PTSD). Forty-five soldiers postblast mTBI, 27 with enduring mTBI symptoms and 18 without, completed a series of neuropsychological tests. Seventeen of the 45 met criteria for PTSD. The Paced Auditory Serial Addition Test (Frencham, Fox, & Mayberry, 2005; Spreen & Strauss, 1998) was the primary outcome measure. Two-sided, 2-sample t tests were used to compare scores between groups of interest. Presence of mTBI symptoms did not impact test performance. In addition, no significant differences between soldiers with and without PTSD were identified. Standard neuropsychological assessment may not increase understanding about impairment associated with mTBI symptoms. Further research in this area is indicated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solving constraint satisfaction problems using hybrid evolutionarysearch

We combine the concept of evolutionary search with the systematic search concepts of arc revision and hill climbing to form a hybrid system that quickly finds solutions to static and dynamic constraint satisfaction problems (CSPs). Furthermore, we present the results of two experiments. In the first experiment, we show that our evolutionary hybrid outperforms a well-known hill climber, the iterative descent method (IDM), on a test suite of 750 randomly generated static CSPs. These results show the existence of a “mushy region” which contains a phase transition between CSPs that are based on constraint networks that have one or more solutions and those based on networks that have no solution. In the second experiment, we use a test suite of 250 additional randomly generated CSPs to compare two approaches for solving CSPs. In the first method, all the constraints of a CSP are known by the hybrid at run-time. We refer to this method as the static method for solving CSPs. In the second method, only half of the constraints of a CSPs are known at run-time. Each time that our hybrid system discovers a solution that satisfies all of the constraints of the current network, one additional constraint is added. This process of incrementally adding constraints is continued until all the constraints of a CSP are known by the algorithm or until the maximum number of individuals has been created. We refer to this second method as the dynamic method for solving CSPs. Our results show hybrid evolutionary search performs exceptionally well in the presence of dynamic (incremental) constraints, then also illuminate a potential hazard with solving dynamic CSPs     

Suicidality and veterans with a history of traumatic brain injury: Precipitating events, protective factors, and prevention strategies.

Objectives: To increase understanding regarding precipitating and preventative factors of suicidal behavior and to highlight past experiences and recommendations regarding services aimed at suicide prevention among Veterans with a history of traumatic brain injury (TBI). Study Design: Qualitative. Participants: Sample of 13 Veterans with a history of TBI, and a history of clinically significant suicidal ideation or behavior. Method: In-person interviews were conducted and data were analyzed using a hermeneutic approach. Results: Shared precipitants noted included loss-of-self post-TBI, cognitive sequelae, and psychiatric and emotional disturbances. Common protective factors noted included social supports, a sense of purpose regarding the future, religion and spirituality, and mental health care. Means of improving care were also identified (e.g., increasing the availability of services and mental health professionals’ knowledge regarding TBI, providing more structured treatment). Conclusions: Findings highlight potential areas of importance in the assessment and treatment of suicidal Veterans with a history of TBI. Recommendations regarding means of improving care are also presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)