DEVELOPMENT AND EVALUATION OF AN ADVANCED REAL-TIME ELECTRICAL POWERED WHEELCHAIR CONTROLLER

Advances in Electric Powered Wheelchairs (EPW) have improved mobility for people with disabilities as well as older adults, and have enhanced their integration into society. Some of the issues still present in EPW lie in the difficulties when encountering different types of terrain, and access to higher or low surfaces. To this end, an advanced real-time electrical powered wheelchair controller was developed. The controller was comprised of a hardware platform with sensors measuring the speed of the driving, caster wheels and the acceleration, with a single board computer for implementing the control algorithms in real-time, a multi-layer software architecture, and modular design. A model based real-time speed and traction controller was developed and validated by simulation. The controller was then evaluated via driving over four different surfaces at three specified speeds. Experimental results showed that model based control performed best on all surfaces across the speeds compared to PID (proportional-integral-derivative) and Open Loop control. A real-time slip detection and traction control algorithm was further developed and evaluated by driving the EPW over five different surfaces at three speeds. Results showed that the performance of anti-slip control was consistent on the varying surfaces at different speeds. The controller was also tested on a front wheel drive EPW to evaluate a forwarding tipping detection and prevention algorithm. Experimental results showed that the tipping could be accurately detected as it was happening and the performance of the tipping prevention strategy was consistent on the slope across different speeds. A terrain-dependent EPW user assistance system was developed based on the controller. Driving rules for wet tile, gravel, slopes and grass were developed and validated by 10 people without physical disabilities. The controller was also adapted to the Personal Mobility and Manipulation Appliance (PerMMA) Generation II, which is an advanced power wheelchair with a flexible mobile base, allowing it to adjust the positions of each of the four casters and two driving wheels. Simulations of the PerMMA Gen II system showed that the mobile base controller was able to climb up to 8” curb and maintain passenger’s posture in a comfort position

Reducir la tasa de abandono entre los profesores de inglés chinos: El papel de la identidad profesional y la autoeficacia

Teachers in any academic setting face a variety of educational challenges and adversities, which may result in unpleasant consequences such as teacher attrition. To minimize the rate of teacher attrition, factors inhibiting this negative phenomenon should be widely recognized. With the related literature reviewed, several researchers have endeavored to locate the potential predictors of teacher attrition in mainstream education environments. Yet, few scholars have explored the predictors of this phenomenon in language education contexts. To fill this lacuna, this research delved into the role of professional identity and self-efficacy in predicting Chinese English teachers’ attrition. In doing this, three valid scales were distributed among 442 English teachers. Correlational tests exhibited that self-efficacy and professional identity are negatively linked to teacher attrition. Multiple regression analysis also indicated that self-efficacy and professional identity can remarkably reduce the rate of attrition among Chinese English teachers. The findings may be informative and illuminating for language teachers and teacher educators.Los profesores en cualquier entorno académico se enfrentan a una variedad de desafíos y adversidades educativas, que pueden resultar en consecuencias desagradables como el abandono de la profesión docente. Para minimizar la tasa de abandono de los profesores, se deben reconocer ampliamente los factores que inhiben este fenómeno negativo. Como revela la revisión de la literatura relacionada, varios investigadores han tratado de localizar los posibles predictores del abandono de los profesores en los entornos educativos generales. Sin embargo, pocos académicos han explorado los predictores de este fenómeno en los contextos de la enseñanza de idiomas. Para llenar este vacío, esta investigación profundizó en el papel de la identidad profesional y la autoeficacia en la predicción del abandono de los profesores de inglés chinos. Para ello, se distribuyeron tres escalas válidas entre 442 profesores de inglés. Las pruebas correlacionales mostraron que la autoeficacia y la identidad profesional están negativamente relacionadas con el abandono de los profesores. El análisis de regresión múltiple también indicó que la autoeficacia y la identidad profesional pueden reducir notablemente la tasa de abandono entre los profesores de inglés chinos. Los hallazgos pueden ser informativos e iluminadores para los profesores y formadores de idiomas

Shared Control of Assistive Robotic Manipulators

The continuum of controlling an assistive robotic manipulator (ARM) ranges from manual control to full autonomy. Shared control of an ARM operates in the space between manual control and full autonomy. This paper reviews the status quo on shared control of ARMs. Though users and ARMs can divide responsibilities for a manipulation task in different ways, most research in this area focus on maximizing robot autonomy and minimizing user control, while other work split the responsibilities more evenly between the ARM and the user. User studies in this area are very limited. More research is needed to investigate the overall performance, workload, and satisfaction across different levels of autonomy for the shared control of ARMs

Complex Dynamics Analysis for a Cournot-Bertrand Mixed Game Model with Delayed Bounded Rationality

A Cournot-Bertrand mixed duopoly game model is constructed. The existence and local stable region of the Nash equilibria point are investigated. Complex dynamic properties such as bifurcation and route to chaos are analyzed using parameter basin plots. The strange attractors are also studied when the system is in chaotic states. Furthermore, considering the memory of the market, a delayed Cournot-Bertrand mixed model is considered and the results show that the delayed system has the same Nash equilibrium and has a higher chance of reaching steady states or cycles than the model without delay. So making full use of the historical data can improve the system’s stability

TACE with Ar-He Cryosurgery Combined Minimal Invasive Technique for the Treatment of Primary NSCLC in 139 Cases

Background and objective TACE, Ar-He target cryosurgery and radioactive seeds implantation are the mainly micro-invasive methods in the treatment of lung cancer. This article summarizes the survival quality after treatment, the clinical efficiency and survival period, and analyzes the advantages and shortcomings of each methods so as to evaluate the clinical effect of non-small cell lung cancer with multiple minimally invasive treatment. Methods All the 139 cases were nonsmall cell lung cancer patients confirmed by pathology and with follow up from July 2006 to July 2009 retrospectively, and all of them lost operative chance by comprehensive evaluation. Different combination of multiple minimally invasive treatments were selected according to the blood supply, size and location of the lesion. Among the 139 cases, 102 cases of primary and 37 cases of metastasis to mediastinum, lung and chest wall, 71 cases of abundant blood supply used the combination of superselective target artery chemotherapy, Ar-He target cryoablation and radiochemotherapy with seeds implantation; 48 cases of poor blood supply use single Ar-He target cryoablation; 20 cases of poor blood supply use the combination of Ar-He target cryoablation and radiochemotheraoy with seeds implantation. And then the pre- and post-treatment KPS score, imaging data and the result of follow up were analyzed. Results The KPS score increased 20.01 meanly after the treatment. Follow up 3 years, 44 cases of CR, 87 cases of PR, 3 cases of NC and 5 cases of PD, and the efficiency was 94.2%. Ninety-nine cases of 1 year survival (71.2%), 43 cases of 2 years survival (30.2%), 4 cases with over 3 years survival and the median survival was 19 months. Average survival was (16±1.5)months. There was no severe complications, such as spinal cord injury, vessel and pericardial aspiration. Conclusion Minimally invasive technique is a highly successful, micro-invasive and effective method with mild complications. To non-small cell lung cancer, we can improve the middle and long term clinical effect by using the different combination of multiple minimally invasive treatments according to the patient's condition

Visualization Experiments of a Specific Fuel Flow Through Quartz-glass Tubes Under both Sub- and Supercritical Conditions

AbstractThe present work is a visualization study of a typical kerosene (RP-3) flowing through vertical and horizontal quartz-glass tubes under both sub- and supercritical conditions by a high speed camera. The experiments are accomplished at temperatures of 300-730 K under pressures from 0.107-5 MPa. Six distinctive two-phase flow patterns are observed in upward flow and the critical point of RP-3 is identified as critical pressure pc=2.33 MPa and critical temperature Tc=645.04 K and it is found that when the fluid pressure exceeds 2.33 MPa the flow can be considered as a single phase flow. The critical opalescence phenomenon of RP-3 is observed when the temperature is between 643.16 K and 648.61 K and the pressure is between 2.308 MPa and 2.366 MPa. The region filled by the critical opalescence in the upward flow is clearly larger than that in the downward flow due to the interaction between the buoyancy force and fluid inertia. Morecover, obvious layered flow phenomenon is observed in horizontal flow under supercritical pressures due to the differences of gravity and density