Fuzzy-logic control of an inverted pendulum with vision feedback

In this paper, the authors present an experimental setup of a fuzzy-logic controller of an inverted pendulum that uses vision feedback. The experimental testbed is used at Oregon State University, USA, in senior and first-year graduate courses on automatic control systems to illustrate the usefulness and limitations of this approach. The results that are obtained support the claim, within certain limits, that it is possible to control an inverted pendulum using fuzzy-logic control and vision feedback     

An improved trajectory tracking decentralized adaptive controllerfor robot manipulators

A decentralized adaptive nonlinear controller for a robot manipulator is presented in this paper. Based on the promising results obtained by the decentralized adaptive PID control algorithms proposed by Seraji and other researchers, the authors redesigned the Lyapunov function, and as a result, achieved a further simplification of the control algorithm and better trajectory tracking performance. The main advantages of the proposed controller over similar controllers are the considerably faster convergence of tracking error, relatively simpler structure, and smoother control activity. Another advantage of this controller is that it only requires local position and velocity measurements, and it does not make use of the exact centralized mathematical model of the robot manipulator. Finally, the authors demonstrate through computer simulation the robustness of their controller against parameter variations and disturbances     

A Communication System Based on Walsh–Hadamard Codes and Constellations for Fading Environments

In this paper, we investigate a new digital communication system based on Walsh-Hadamard codes. The modulator maps a uniformly distributed binary source to a set of symbols with a Gaussian-like distribution. These symbols are then mapped to a 2-D constellation in such a way that performance is improved when transmission occurs over Rayleigh fading channels. We assess the performance of these modulation schemes when the channel is of the nonfrequency-selective Rayleigh fading plus white Gaussian noise type and compare the results to conventional quadrature-amplitude modulation (QAM) schemes with comparable spectral efficiencies. The proposed system provides excellent robustness to fading without the use of common diversity schemes employed in M-ary signaling systems to improve bit-error-rate (BER) performance in such environments.     

A sequenced multimodal learning approach to support students' development of conceptual learning

Virtual learning environments can now be enriched not only with visual and auditory information, but also with tactile and kinesthetic feedback. However, the way to successfully integrate haptic feedback on a multimodal learning environment is still unclear. This study aims to provide guidelines on how visuohaptic simulations can be implemented effectively, thus the research question is: Under what conditions do visual and tactile information support students' development of conceptual learning of force‐related concepts? Participants comprised 170 undergraduate students of a Midwestern University enrolled in a physics for elementary education class. Four experiments were conducted using four different configurations of multimodal learning environments: Visual feedback only, haptic force feedback only, visual and haptic force feedback at the same time, and sequenced modality of haptic feedback first and visual feedback second. Our results suggest that haptic force feedback has the potential to enrich learning when compared with visual only environments. Also, haptic and visual modalities interact better when sequenced one after another rather than presented simultaneously. Finally, exposure to virtual learning environments enhanced by haptic forced feedback was a positive experience, but the ease of use and ease of interpretation was not so evident.     

Unpacking students' conceptualizations through haptic feedback

While it is clear that the use of computer simulations has a beneficial effect on learning when compared to instruction without computer simulations, there is still room for improvement to fully realize their benefits for learning. Haptic technologies can fulfill the educational potential of computer simulations by adding the sense of touch. Visuohaptic simulations may not only help students visualize these concepts, but they may also have the capability of enriching the learning experience and enhancing retention. To provide additional insights about how students conceptualize abstract and difficult concepts in science, this study proposes a sequencing approach. The research questions are: (1) what are undergraduate students' ways of conceptualizing electric fields through haptic feedback? And (2) what are undergraduate students' perceptions of using visuohaptic simulations for their learning of electric force concepts? Participants included nine undergraduate students who participated in a think aloud procedure. Data were analysed qualitatively using open coding followed by axial coding. The results suggest that students' conceptualized electric force concepts through embodied haptic experiences by inferring force–distance relationship, sign inference, shape of field and indirectly inferring the concept of electric potential. Students also perceived the value of using visual plus haptic simulations to help them understand and retain concepts.     

From ethnography to intervention: developing a breast cancer control program for Latinas

Latinas are less likely than Anglo women to have appropriate breast cancer screening for reasons that may include culturally based beliefs as well as socioeconomic factors. This study employed ethnographic methods to explore breast cancer-related knowledge, attitudes, and behaviors among Latinas, Anglo women, and physicians, tested the generalizability of the findings in a telephone survey of randomly selected women, and used the results to design a culturally sensitive breast cancer control intervention in Orange County, Calif. Respondents for the ethnographic interviews included 28 Salvadoran immigrants, 39 Mexican immigrants, 27 Chicanas (U.S.-born Latinas of Mexican heritage), 27 Anglo women, and 30 physicians selected through organization-based network sampling. Latinas had very different beliefs about risk factors for breast cancer and held more fatalistic attitudes about the disease. For example, they believed that trauma to the breast was among the most important risk factors. Results of a telephone survey of 1225 randomly selected women (269 U.S.-born Latinas, 425 Mexican immigrants, 109 other Latina immigrants, and 422 Anglo women) generally confirmed the dissimilar beliefs among Latinas and Anglo women. The findings influenced our decision to design and pilot-test a breast cancer control intervention based on Bandura's self-efficacy theory and Freire's empowerment pedagogy. The methodology and findings of this study have important implications for future cancer control research and interventions.     

Apparatus Prototype for Purposes of Teaching in Bio-digesters

A mathematical model is developed based on a simplified mechanism of anaerobic digestion. The main objective is to quantitatively analyze the digestion process to optimize operating conditions and maintenance of this equipment, which could be used to test different materials and be able to apply these results to the possible scaling to bio-digesters installed in the field. The experiments were carried out in a hybrid system bio-digester photovoltaic cells. The bio-digester is made of stainless steel with dimensions to treat an average of 10 kg of raw material and produce biogas from different organic materials. The reactor has been conditioned with temperature sensors, pressure and methane gas that allow monitoring the concentration of the gas and the conditions of operation during the time of digestion. The system has a photovoltaic array to provide the energy required to keep the temperature constant, The experiment was conducted using materials such as goat manure mixed with household waste, and various formulations of these materials were prepared. The experimental results were used to test the mathematical model.