Contact-Aided Invariant Extended Kalman Filtering for Legged Robot State Estimation

This paper derives a contact-aided inertial navigation observer for a 3D bipedal robot using the theory of invariant observer design. Aided inertial navigation is fundamentally a nonlinear observer design problem; thus, current solutions are based on approximations of the system dynamics, such as an Extended Kalman Filter (EKF), which uses a system's Jacobian linearization along the current best estimate of its trajectory. On the basis of the theory of invariant observer design by Barrau and Bonnabel, and in particular, the Invariant EKF (InEKF), we show that the error dynamics of the point contact-inertial system follows a log-linear autonomous differential equation; hence, the observable state variables can be rendered convergent with a domain of attraction that is independent of the system's trajectory. Due to the log-linear form of the error dynamics, it is not necessary to perform a nonlinear observability analysis to show that when using an Inertial Measurement Unit (IMU) and contact sensors, the absolute position of the robot and a rotation about the gravity vector (yaw) are unobservable. We further augment the state of the developed InEKF with IMU biases, as the online estimation of these parameters has a crucial impact on system performance. We evaluate the convergence of the proposed system with the commonly used quaternion-based EKF observer using a Monte-Carlo simulation. In addition, our experimental evaluation using a Cassie-series bipedal robot shows that the contact-aided InEKF provides better performance in comparison with the quaternion-based EKF as a result of exploiting symmetries present in the system dynamics.Comment: Published in the proceedings of Robotics: Science and Systems 201

Iran's activities on prevention, treatment and harm reduction of drug abuse

Context: In the present review study, authors investigated Iran's activities regarding prevention, abuse and harm reduction of drugs nationwide. The issue appears to be important in order to show the trend of activities in the country. Evidence Acquisition: In this report, authors gathered data from different Farsi/English peer review journals issued both in printed and online versions. These journals have been indexed in PubMed, ISI, ISC, SID, Magiran, UN, etc. These are among the most referred and cited databases. Results: Summarizing the data led to three distinguished sections: 1) drug supply reduction activities; 2) drug demand reduction activities; 3) harm reduction activities. Conclusions: As the results showed, the trend of activities was encouraging and some additional activities could be included to future programs relying on early-onset preventions. © 2015, Zahedan University of Medical Sciences

Warped Gaussian Processes Occupancy Mapping with Uncertain Inputs

© 2017 IEEE. In this paper, we study extensions to the Gaussian processes (GPs) continuous occupancy mapping problem. There are two classes of occupancy mapping problems that we particularly investigate. The first problem is related to mapping under pose uncertainty and how to propagate pose estimation uncertainty into the map inference. We develop expected kernel and expected submap notions to deal with uncertain inputs. In the second problem, we account for the complication of the robot's perception noise using warped Gaussian processes (WGPs). This approach allows for non-Gaussian noise in the observation space and captures the possible nonlinearity in that space better than standard GPs. The developed techniques can be applied separately or concurrently to a standard GP occupancy mapping problem. According to our experimental results, although taking into account pose uncertainty leads, as expected, to more uncertain maps, by modeling the nonlinearities present in the observation space WGPs improve the map quality

Folate-conjugated nanoparticles as a potent therapeutic approach in targeted cancer therapy

The selective and efficient drug delivery to tumor cells can remarkably improve different cancer therapeutic approaches. There are several nanoparticles (NPs) which can act as a potent drug carrier for cancer therapy. However, the specific drug delivery to cancer cells is an important issue which should be considered before designing new NPs for in vivo application. It has been shown that cancer cells over-express folate receptor (FR) in order to improve their growth. As normal cells express a significantly lower levels of FR compared to tumor cells, it seems that folate molecules can be used as potent targeting moieties in different nanocarrier-based therapeutic approaches. Moreover, there is evidence which implies folate-conjugated NPs can selectively deliver anti-tumor drugs into cancer cells both in vitro and in vivo. In this review, we will discuss about the efficiency of different folate-conjugated NPs in cancer therapy. © 2015, International Society of Oncology and BioMarkers (ISOBM)

Exposure to GSM 900-MHz mobile radiation impaired inhibitory avoidance memory consolidation in rat: Involvements of opioidergic and nitrergic systems

Abstract The use of mobile phones is increasing, and the main health concern is the possible deleterious effects of radiation on brain functioning. The present study aimed to examine the effects of exposure to a global system for mobile communication (GSM) with mobile phones on inhibitory avoidance (IA) memory performance as well as the involvement of endogenous opioids and nitric oxide (NO) in this task. Male Wistar rats, 10–12 weeks old, were used. The results showed that four weeks of mobile phone exposure impaired IA memory performance in rats. The results also revealed that post-training, but not pre-training, as well as pre-test intracerebroventricular (i.c.v.) injections of naloxone (0.4, 4 and 40 ng/rat), dose-dependently recovered the impairment of IA memory performance induced by GSM radiation. Additionally, the impairment of IA memory performance was completely recovered in the exposed animals with post-training treatment of naloxone (40 ng/rat) plus pre-test i.c.v. injections of L-arginine (100 and 200 nmol/rat). However, pre-test i.c.v. injections of L-NAME (10 and 20 nmol/rat), impaired IA memory performance in the animals receiving post-training naloxone (40 ng/rat). In the animals receiving post-training naloxone treatment, the impairment of IA memory performance due to pre-test i.c.v. injections of L-NAME was recovered by the pre-test co-administration of L-arginine. It was concluded that the recovery from impairment of IA memory in GSM-exposed animals with post-training naloxone treatment was the result of blockade of the opioidergic system in early memory consolidation as well as activation of the nitrergic system in the retrieval phase of memory. Keywords: GSM 900-MHz Endogenous opioids Memory performance Consolidation Nitric oxid

The effect of methadone-maintenance therapy with and without interactive treatment on improving emotion-regulation strategies and resilience among opiate-dependent clients

Background: Due to the chronic and recurrent nature of addiction, many people who quit drug addiction may slip back into the pattern of using drugs shortly after the detoxification period. Emotion-regulation strategies and resilience play an important role in preventing the recurrences of substance abuse. Objectives: This study aimed to compare the effects of methadone-maintenance therapy (MMT) and interactive therapy (a combination of MMT and cognitive-behavioral therapy) on improving emotion-regulation strategies and resilience among opiate-dependent clients. Patients and Methods: This pretest-posttest quasi-experimental study was performed on 60 patients with substance abuse admitted to Methadone Addiction Treatment Centers and Detox Centers in Sari within three months of therapy for their addiction (from October to December 2013). Then, the participants were randomly assigned to two different groups (n = 30) were examined in two groups of 30 people targeted to be available in the selected population. Participants in all three groups, before and after the intervention, filled out the questionnaires of Schutte emotional intelligence scale and Connor-Davidson resiliency questionnaire. Data were analyzed using the analysis of covariance method. Results: The results showed that an interactive therapy would be significantly more effective than the MMT on improving emotion-regulation strategies and promoting the resilience level among opiate-dependent clients. Moreover, the results showed that cognitive- behavior therapy combined with MMT may improve emotion-regulation strategies, and promote the amount of resiliency and recovery. Conclusions: The cognitive-behavior therapy combined with MMT can improve emotion-regulation strategies and resiliency and thus prevent the substance-abuse relapse. © 2015, Zahedan University of Medical Sciences

An Audio-visual Solution to Sound Source Localization and Tracking with Applications to HRI

Robot audition is an emerging and growing branch in the robotic community and is necessary for a natural Human-Robot Interaction (HRI). In this paper, we propose a framework that integrates advances from Simultaneous Localization And Mapping (SLAM), bearing-only target tracking, and robot audition techniques into a unifed system for sound source identification, localization, and tracking. In indoors, acoustic observations are often highly noisy and corrupted due to reverberations, the robot ego-motion and background noise, and possible discontinuous nature of them. Therefore, in everyday interaction scenarios, the system requires accommodating for outliers, robust data association, and appropriate management of the landmarks, i.e. sound sources. We solve the robot self-localization and environment representation problems using an RGB-D SLAM algorithm, and sound source localization and tracking using recursive Bayesian estimation in the form of the extended Kalman Filter with unknown data associations and an unknown number of landmarks. The experimental results show that the proposed system performs well in the medium-sized cluttered indoor environment