DeepSym: Deep Symbol Generation and Rule Learning from Unsupervised Continuous Robot Interaction for Planning

Autonomous discovery of discrete symbols and rules from continuous interaction experience is a crucial building block of robot AI, but remains a challenging problem. Solving it will overcome the limitations in scalability, flexibility, and robustness of manually-designed symbols and rules, and will constitute a substantial advance towards autonomous robots that can learn and reason at abstract levels in open-ended environments. Towards this goal, we propose a novel and general method that finds action-grounded, discrete object and effect categories and builds probabilistic rules over them that can be used in complex action planning. Our robot interacts with single and multiple objects using a given action repertoire and observes the effects created in the environment. In order to form action-grounded object, effect, and relational categories, we employ a binarized bottleneck layer of a predictive, deep encoder-decoder network that takes as input the image of the scene and the action applied, and generates the resulting object displacements in the scene (action effects) in pixel coordinates. The binary latent vector represents a learned, action-driven categorization of objects. To distill the knowledge represented by the neural network into rules useful for symbolic reasoning, we train a decision tree to reproduce its decoder function. From its branches we extract probabilistic rules and represent them in PPDDL, allowing off-the-shelf planners to operate on the robot's sensorimotor experience. Our system is verified in a physics-based 3d simulation environment where a robot arm-hand system learned symbols that can be interpreted as 'rollable', 'insertable', 'larger-than' from its push and stack actions; and generated effective plans to achieve goals such as building towers from given cubes, balls, and cups using off-the-shelf probabilistic planners

Voltage-mode PID controller design employing canonical number of active and passive elements

This paper originality is put forward a second-generation voltage conveyor (VCII) based voltage-mode PID controller. The proposed circuit includes a single VCII-, two capacitors, two resistors, and no need any passive component matching conditions. The sensitivity has been investigated for the control parameters. Besides, the impacts on operating frequency ranges of the parasitic impedances have been examined. Simulation outcomes have been obtained by operating TSMC 0.18 mu m CMOS technology parameters with power supply +/- 0.9 V. Additionally, a closed-loop control system application is included to demonstrate the circuit's functioning. An experimental study is given to confirm the time-domain performance of the proposed circuit by using commercially available integrated circuits

Attitude Control and Parameter Optimization: A Study on Hubble Space Telescope

In this work, we build a satellite attitude Proportional-Integral-Derivative (PID) controlled system by using the Hubble Space Telescope (HST) parameters as a reference and tune its controller parameters using various tuning methods. First, we give the equations for the motion of a satellite. We elaborate the control structure as controller, actuator, dynamics, and kinematics subsystems and construct an external disturbance model. We use a reaction wheel assembly used in the HST with the same configuration as the actuator. We evaluate the performance of the linearization by comparing it with the nonlinear model output. By working on the linearized model, we tune the PID controller parameters using two different methods: “Model-Based Root Locus Tuning” and “Genetic Algorithm Based Tuning”. First, we obtain the controller parameters by manipulating the poles on the root locus plot of the linearized system. In addition, we use genetic algorithms to find the optimized controller values of the system. Finally, we compare the performances of the two methods based on their cost function values and find that the Genetic Algorithm-based tuned parameters are more fruitful in terms of the cost function value than the parameters obtained by the Root Locus-based tuning. However, it is found that the Root Locus-based tuning performs better in disturbance rejection

Photocurrent and hydrogen production by overall water splitting based on polymeric composite Calix[n]arene/Cyanin Dye/IrO2 nanoparticle

In this study, a new photoelectrochemical cell based on overall splitting of water into oxygen and hydrogen is constructed to obtain an improved photocurrent under a visible range of light. The photoanode was obtained by a gold electrode (GE) modified with carboxylic acid functionalized SH-Calix-4-arene-COOH and IrO2 nanoparticles attached light absorbing cyanine dye via polymeric oligoaniline linkages. The conductive polymer, 4- (4H-Dithieno [3,2-b: 2 ′, 3′-d] pyrrol-4-yl)aniline, was coated on GE using electropolymerization and used as a photocathode after platinum nanoparticles (Pt) were attached on the surface. The system was illuminated under the visible light, and the water was oxidized via IrO2 catalyst to produce hydrogen on the photocathode side while oxygen on the photoanode. A photocurrent density of 182.03 μA cm−2 was obtained by direct transfer of electrons without using a mediator. The bilirubin oxidase (BOx) enzyme was successfully used to remove excess oxygen from the reaction chamber and a further increase in photocurrent was reached up to 272.44 μA cm−2. Hydrogen production in the reaction chamber was measured by gas chromatography at different time intervals and a maximum of 1.25 × 10−8 mol cm−2 was obtained. [Display omitted] •A photoelectrochemical cell generating photocurrent via water splitting was constructed.•Calix[n]arene/Cyanin Dye/IrO2 structure was used transfer electrons in high efficiency.•Electrocatalytic reduction of O2 into water is achieved by Bilirubin Oxidase.•The maximum power of 15.6 mW m−2 was reached at a current density of 39.6 mA m−2

A multidisciplinary analysis of the fire propagation in the aspiration system of a building

This paper aims to investigate the potential causes of a fire event that occurred in a fabric finishing facility with washing and drying units. The research methodology employed includes fieldwork, laboratory tests, and numerical analysis to identify potential factors contributing to the fire event. In the first stage, a field study was carried out and investigations were made at the fire site. In the second stage of the study, samples were taken from the fire site and chemical analyses were conducted in a laboratory. In the third stage, computational fluid dynamics (CFD) analyses were performed based on different hypotheses to simulate the fire event. These numerical analyses were conducted using the Fire Dynamics Simulator (FDS) program, an open-source field model developed by the National Institute of Standards and Technology (NIST) of USA. This program has been widely used by researchers in many institutes around the world to simulate different scenarios related to fire phenomena. The data collected in these stages were analyzed to identify the root causes of the fire incident. The multidisciplinary approach presented in this study is expected to make a significant contribution to the literature for determining the causes of similar fire events and strategies for fire prevention

Effects of cerebral oxygen changes during coronary bypass surgery on postoperative cognitive dysfunction in elderly patients: a pilot study

Background and objectives: Postoperative cognitive dysfunction is common after cardiac surgery. Adequate cerebral perfusion is essential and near infrared spectroscopy (NIRS) can measure cerebral oxygenation. Aim of this study is to compare incidence of early and late postoperative cognitive dysfunction in elderly patients treated with conventional or near infrared spectroscopy monitoring. Methods: Patients undergoing coronary surgery above 60 years, were included and randomized to 2 groups; control and NIRS groups. Peroperative management was NIRS guided in GN; and with conventional approach in control group. Test battery was performed before surgery, at first week and 3rd month postoperatively. The battery comprised clock drawing, memory, word list generation, digit spam and visuospatial skills subtests. Postoperative cognitive dysfunction was defined as drop of 1 SD (standard deviation) from baseline on two or more tests. Mann-Whitney U test was used for comparison of quantitative measurements; Chi-square exact test to compare quantitative data. Results: Twenty-one patients in control group and 19 in NIRS group completed study. Demographic and operative data were similar. At first week postoperative cognitive dysfunction were present in 9 (45%) and 7 (41%) of patients in control group and NIRS group respectively. At third month 10 patients (50%) were assessed as postoperative cognitive dysfunction; incidence was 4 (24%) in NIRS group (p:0.055). Early and late postoperative cognitive dysfunction group had significantly longer ICU stay (1.74 + 0.56 vs. 2.94 + 0.95; p < 0.001; 1.91 + 0.7 vs. 2.79 + 1.05; p < 0.01) and longer hospital stay (9.19 + 2.8 vs. 11.88 + 1.7; p < 0.01; 9.48 + 2.6 vs. 11.36 + 2.4; p < 0.05). Conclusion: In this pilot study conventional monitoring and near infrared spectroscopy resulted in similar rates of early postoperative cognitive dysfunction. Late cognitive dysfunction tended to ameliorate with near infrared spectroscopy. Early and late cognitive declines were associated with prolonged ICU and hospital stays. Resumo: Justificativa e objetivos: A disfunção cognitiva no pós-operatório é comum após cirurgia cardíaca. A perfusão cerebral adequada é essencial, e a espectroscopia no infravermelho próximo (NIRS) pode medir a oxigenação cerebral. O objetivo deste estudo foi comparar a incidência de disfunção cognitiva no pós-operatório, precoce e tardio, em pacientes idosos tratados com monitorização convencional ou espectroscopia no infravermelho próximo. Métodos: Os pacientes submetidos à cirurgia coronariana, acima de 60 anos de idade, foram incluídos e randomicamente alocados em dois grupos: Grupo controle e Grupo NIRS. O manejo dos pacientes no período peroperatório foi realizado com NIRS no grupo NH e com abordagem convencional no grupo controle. A bateria de testes foi feita antes da cirurgia, na primeira semana e no terceiro mês de pós-operatório. A bateria incluiu o desenho do relógio, a memória, a geração de uma lista de palavras, a sequência de dígitos e subtestes que exigem habilidades visuoespaciais. Disfunção cognitiva no pós-operatório foi definida como queda de um DP (desvio-padrão) da fase basal em dois ou mais testes. O teste U de Mann Whitney foi usado para comparação de medidas quantitativa e o teste exato do qui-quadrado para comparar dados quantitativos. Resultados: Vinte e um pacientes do grupo controle e 19 do grupo NIRS concluíram o estudo. Os dados demográficos e operacionais foram semelhantes. Na primeira semana, nove pacientes (45%) do GC e sete pacientes (41%) do grupo NIRS apresentaram disfunção cognitiva no pós-operatório. No terceiro mês, 10 pacientes (50%) foram avaliados como disfunção cognitiva no pós-operatório; a incidência foi de quatro (24%) no grupo NIRS (p: 0,055). O grupo que apresentou disfunção cognitiva no pós-operatório precoce e tardio teve uma permanência significativamente maior na UTI (1,74 + 0,56 vs. 2,94 + 0,95; p < 0,001; 1,91 + 0,7 vs. 2,79 + 1,05; p < 0,01) e permanência hospitalar mais longa (9,19 + 2,8 vs. 11,88 + 1,7; p < 0,01; 9,48 + 2,6 vs. 11,36 + 2,4; p < 0,05). Conclusão: Neste estudo piloto, a monitorização convencional e espectroscopia no infravermelho próximo resultaram em taxas semelhantes de disfunção cognitiva no pós-operatório precoce. A disfunção cognitiva tardia tende a melhorar com espectroscopia no infravermelho próximo. Os declínios cognitivos precoces e tardios foram associados a internações prolongadas tanto em UTI quanto hospitalares. Keywords: Postoperative cognitive dysfunction, Cerebral oximetry, Cardiac surgery, Elderly patient, Palavras-chave: Disfunção cognitiva no pós-operatório, Oximetria cerebral, Cirurgia cardíaca, Paciente idos