Raman Paranjape

Evaluation of age-related differences in the stride-to-stride fluctuations, regularity and symmetry of gait using a waist-mounted tri-axial accelerometer

PURPOSE To compare the stride-to-stride fluctuations, regularity and symmetry of gait using a body-fixed accelerometer in a group of healthy young and healthy older adults. METHODS Forty-one healthy young adults (24 ± 3 years) and forty-one healthy older adults (76 ± 5 years) completed a 10-min walk at a self-selected, normal walking speed while wearing a single waist-mounted tri-axial accelerometer. The following gait parameters were compared between age groups: mean step and stride time, step and stride time variability, stride time fractal scaling index and the regularity and symmetry of the acceleration pattern in the vertical, mediolateral and anteroposterior directions (unbiased autocorrelation procedure). RESULTS Older adults displayed significantly greater step and stride time variability (p<0.05) and a lower stride time fractal scaling index (p<0.01), as well as significantly less regularity (p<0.05) and symmetry (p<0.05) of the anteroposterior accelerations. CONCLUSION The results show that healthy older adults possess greater temporal gait variability, as well as a less-organized and repeatable pattern of variability and acceleration in the direction of motion, than younger adults. The findings also suggest the presence of an age-related decline in the anteroposterior control of gait, but not in the vertical and mediolateral control of gait.

An indexed atlas of digital mammograms for computer-aided diagnosis of breast cancer

Computer-aided diagnosis (cad) systems are being developed to assist radiologists in the interpretation of ambiguous mammographic features corresponding to possible signs of early breast cancer. Databases of digital mammograms are needed for testing such systems; we present an overview of a few such databases. Most databases are limited to single-exam sets of two or four mammograms on which the diagnosis was made, some ground-truth information related to the position of diagnostically significant mammographic features, and the diagnosis. We propose the design of a comprehensive, indexed atlas of digital mammograms. The design of an appropriate indexing scheme facilitates the implementation of content-based retrieval techniques needed for efficient access to and retrieval of relevant cases from the atlas.We also propose the use of mobile software agents for facilitating remote consultation of the atlas. Mobile agents can move between data sources such as the atlas and hospital repositories, perform computational tasks at each site, and return only relevant data to the user. These features reduce the computational requirements of the local computer system, bandwidth requirements, and overall network traffic. Proposed applications of the atlas include research, remote consultation, teaching, evaluation ofcad systems, and self-evaluation by radiologists.RésuméLes systèmes d’aide au diagnostic (Computer-Aided Diagnosis,cad) sont développés pour faciliter le travail des radiologues en matière d’interprétation des images mammographiques dans l’objectif d’une détection précoce de cancer du sein. Pour la validation de tels systèmes, on a besoin de bases de données de radiographies numérisées du sein; nous présentons un aperçu de quelques bases de données. La plupart des bases de données se limitent à des ensembles de deux à quatre images sur lesquelles un diagnostic a été réalisé, quelques réalités de terrain (ground truth) concernant les caractéristiques significatives des mammographies, et les diagnostics. Dans cet article, nous proposons la conception d’un atlas indexé et détaillé des radiographies du sein. La conception d’un plan d’indexation propre facilite l’implémentation des techniques de recherche basées sur le contenu informationnel (Content-Based Retrieval) dont on a besoin pour un accès efficace et rapide aux cas pertinents contenus dans l’atlas.Nous proposons aussi l’utilisation du concept d’agent logiciel mobile pour faciliter la consultation à distance de l’atlas. Les agents logiciels mobiles peuvent se déplacer entre les différentes sources d’information comme l’atlas et les systèmes d’information hospitaliers, faire des calculs à chaque site et envoyer ensuite les seules informations pertinentes à l’usager. Ces caractéristiques vont réduire les exigences des ordinateurs locaux, les exigences en bande passante et le trafic numérique. Les applications de l’atlas comportent la recherche, la consultation à distance, l’enseignement, l’évaluation des systèmes decao, et l’auto-évaluation par les radiologues.

Residential demand response: An overview of recent simulation and modeling applications

This paper reviews recent simulation and modeling applications of residential demand response including demand response enabled load models, home energy management systems, and multi-agent systems. Demand response implementation in residential sectors is a recent effort to improve efficiency of the electricity market and stability of the power system. The benefits are significant; however the investment and potential risks are nonnegligible. Simulation and modeling is a desirable way to identify and quantify impacts and benefits of demand response applications. The two main aims of these applications are to reduce electricity peak demand and to match the demand with renewable energy. The flexible demand aspect enables time-shift electricity consumption by bringing forward or delaying the use of appliances. Therefore, developing applicable residential load models and efficiency home energy management systems are critical issues to allow incorporation of dynamic electric use patterns. Multi-agent systems allows evaluating various components of further power system or smart grid including distributed generator, microgrid, distribution intelligence, etc..

Dynamic analysis and human analogous control of a pipe crawling robot

In this paper the design and development of a crawling robot for inspection of live water pipes are addressed. The mechanical design of the robot is described in detail. The governing dynamics equations of the robot moving against water flow as well as gravity in a straight pipe are also derived. Specifically, the hydrodynamic forces exerted on the robot when moving in a live pressurized pipe are taken into account. Two fuzzy-logic based control strategies are adopted. The first one is to maintain a constant translational speed in robots motion when subjected to flow disturbances that are numerically modeled using step changes in flow velocity within a human-in-the-loop real-time simulation environment, and the second is to steer the real robot inside the pipe while following a numerically modeled time-varying velocity set point with no fluid present in the pipe. The controller parameters were tuned based on data obtained from a human-in-the-loop control system via an artificial neural network.

Optimal Residential Demand Response for Multiple Heterogeneous Homes With Real-Time Price Prediction in a Multiagent Framework

Demand response (DR) is a recent effort to improve the efficiency of the electricity market and the stability of the power system. A successful implementation relies on both appropriate policy design and enabling technology. This paper presents a multiagent system to evaluate optimal residential DR implementation in a distribution network, in which the main stakeholders are modeled by heterogeneous home agents (HAs) and a retailer agent (RA). The HA is able to predict and control electricity load demand. A real-time price prediction model is developed for the HA and the RA. The optimal control of electricity consumption is formulated into a convex programming problem to minimize electricity payment and waiting time under real-time pricing. Simulation results show that the peak-to-average power ratio and electricity payments are significantly reduced using the proposed algorithms. The HA, with the proposed optimal control algorithms, can be embedded into a home energy management system to make intelligent decisions on behalf of homeowners responding to DR policies. The proposed agent system can be utilized to evaluate various strategies and emerging technologies that enable the implementation of DR.

An Evaluation of Electric Vehicle Penetration under Demand Response in a Multi-Agent Based Simulation

This paper proposes an electric vehicle charging model and various control algorithms that are further incorporated into a multi-agent system to evaluate impacts of electric vehicle penetration on the power system. Electric vehicles have become increasingly popular due to the high costs of the operation of gas / diesel powered vehicles and the potential to reduce CO2 emission. In this work, we propose the electric vehicle charging model and associated control algorithms to aggregate the electric vehicle load. Simulation results show that uncontrolled charging of electric vehicles can jeopardize the stability of the power system. In a worst-case scenario this can lead to an increase of peak demand by 53.2%, while by using appropriate scheduled charging the electric vehicles can have no contribution to the peak demand. Furthermore, scheduled charging dramatically reduces the standard deviation of the residential load (by up to 51%). Therefore, the aggregation of electric vehicle demand under an appropriate demand response control strategy has the potential to dramatically improve the stability of the power system with virtually no negative impacts. The proposed electric vehicle charging model and the associated scheduling algorithm can be embedded into a home energy management system or a smart charger.

An eye-to-hand visual servoing structure for 3D positioning of a robotic arm using one camera and a flat mirror

This paper introduces a novel visual servoing structure for 3D robot positioning under an eye-to-hand camera configuration. The proposed algorithm is based on image-based visual servoing (IBVS) using only one camera in conjunction with a flat mirror. A landmark mounted on the robot along with its mirror reflection, when viewed by the camera, provides enough information for 3D reasoning based on a 2D image. The governing equations describing the relationship between the robots velocity and rate of change in image features are fully described. Furthermore, a methodology for on-line estimation of the image Jacobian with no camera calibration is developed. Simulation and experimental results illustrate the robustness of the proposed visual servoing structure.

Agent behavior and agent models in unregulated markets

Mobile-agent systems show significant promise as the most effective way to harness the power of the Internet and the massive collection of information and opportunity that the Internet holds. However the efficient organization and control of these systems remains one of a number of unsolved problems with this approach to network computing. This paper examines a mobile-agent system with specific focus on environment sensing, preemptive load balancing and open agent markets. Agent behaviour is studied with actual agent systems using progressively sophisticated agent migration strategies.It is shown that actual modeling shows interesting and difficult to predict behaviour in the agent systems. It is shown that mobile agents with relatively simple migration strategies can cause loads in self-regulating agent markets to oscillate. It is further shown that using Autoregressive modeling to predict the market behaviour can allow individual agents to significantly outperform other agents. However the fidelity of the model is critical to the success of the agents. The criticality of good agent strategies and actual agent system modeling is thus highlighted.

Agent-Based Simulation of Healthcare for Type II Diabetes

Healthcare delivery systems around the world are faced with growing demand to provide a better-quality standard of care and at the same time keep the cost and resource utilization minimal. Statistics reveal that diabetes is a major issue in the healthcare industry and there is a strong need to address this problem in order to improve and reduce the cost of its treatment. Furthermore, evidence of the effectiveness of self-monitoring blood glucose levels is unclear, particularly in patients with Type 2 diabetes. In this study, interaction between the diabetic patient and the physician in current healthcare settings is modeled and simulated using software agent technology to demonstrate the long term clinical-effectiveness and cost-effectiveness of various diabetic interventions such as self-monitoring and lifestyle adjustments.

Design and Development of a Hardware-in-the Loop Simulation System for a Submersible Pipe Inspecting Robot

An autonomous smart vehicle for doing in service water pipe inspection has been designed and built at the University of Regina. The robot can crawl inside in-service horizontal/vertical water pipes. The spinning head of the robot can generate a helical forward motion utilizing a track of sprung wheels positioned with an angle with respect to the longitudinal axis of the robot. The wheels can exert a normal force onto the inner wall of the pipe supporting robots own weight when moving vertical. The translational motion (i.e., position and velocity) of the main body of the robot carrying onboard non-destructive testing units and/or navigation sensors must be accurately controlled for precise inspection of pipes at any bandwidth and/or accurate autonomous navigation. For this purpose, a hardware-in-the-loop simulation system is proposed for rapid prototyping of different control strategies for regulating robots movement taking the hydrodynamic forces exerted on the system and its dynamics into account