Self-organized Collective Motion with a Simulated Real Robot Swarm

Collective motion is one of the most fascinating phenomena observed in the nature. In the last decade, it aroused so much attention in physics, control and robotics fields. In particular, many studies have been done in swarm robotics related to collective motion, also called flocking. In most of these studies, robots use orientation and proximity of their neighbors to achieve collective motion. In such an approach, one of the biggest problems is to measure orientation information using on-board sensors. In most of the studies, this information is either simulated or implemented using communication. In this paper, to the best of our knowledge, we implemented a fully autonomous coordinated motion without alignment using very simple Mona robots. We used an approach based on Active Elastic Sheet (AES) method. We modified the method and added the capability to enable the swarm to move toward a desired direction and rotate about an arbitrary point. The parameters of the modified method are optimized using TCACS optimization algorithm. We tested our approach in different settings using Matlab and Webots

Comparison of different cue-based swarm aggregation strategies

In this paper, we compare different aggregation strategies for cue-based aggregation with a mobile robot swarm. We used a sound source as the cue in the environment and performed real robot and simulation based experiments. We compared the performance of two proposed aggregation algorithms we called as the vector averaging and naïve with the state-of-the-art cue-based aggregation strategy BEECLUST. We showed that the proposed strategies outperform BEECLUST method. We also illustrated the feasibility of the method in the presence of noise. The results showed that the vector averaging algorithm is more robust to noise when compared to the naïve method

COSΦ: Vision-based artificial pheromone system for robotic swarms

We propose a novel spatio-temporal mobile-robot exploration method for dynamic, human-populated environments. In contrast to other exploration methods that model the environment as being static, our spatio-temporal exploration method creates and maintains a world model that not only represents the environment's structure, but also its dynamics over time. Consideration of the world dynamics adds an extra, temporal dimension to the explored space and makes the exploration task a never-ending data-gathering process to keep the robot's environment model up-to-date. Thus, the crucial question is not only where, but also when to observe the explored environment. We address the problem by application of information-theoretic exploration to world representations that model the environment states' uncertainties as probabilistic functions of time. The predictive ability of the spatio-temporal model allows the exploration method to decide not only where, but also when to make environment observations. To verify the proposed approach, an evaluation of several exploration strategies and spatio-temporal models was carried out using real-world data gathered over several months. The evaluation indicates that through understanding of the environment dynamics, the proposed spatio-temporal exploration method could predict which locations were going to change at a specific time and use this knowledge to guide the robot. Such an ability is crucial for long-term deployment of mobile robots in human-populated spaces that change over time

Molecular Signal Modeling of a Partially Counting Absorbing Spherical Receiver

To communicate at the nanoscale, researchers have proposed molecular communication as an energy-efficient solution. The drawback to this solution is that the histogram of the molecules' hitting times, which constitute the molecular signal at the receiver, has a heavy tail. Reducing the effects of this heavy tail, inter-symbol interference (ISI), has been the focus of most prior research. In this paper, a novel way of decreasing the ISI by defining a counting region on the spherical receiver's surface facing towards the transmitter node is proposed. The beneficial effect comes from the fact that the molecules received from the back lobe of the receiver are more likely to be coming through longer paths that contribute to ISI. In order to justify this idea, the joint distribution of the arrival molecules with respect to angle and time is derived. Using this distribution, the channel model function is approximated for the proposed system, i.e., the partially counting absorbing spherical receiver. After validating the channel model function, the characteristics of the molecular signal are investigated and improved performance is presented. Moreover, the optimal counting region in terms of bit error rate is found analytically.Comment: submitted to Transactions on Communication

Optimal Design of an In-flight Refueling Door Mechanism

In this study, the preliminary design of an in-flight refueling door mechanism is performed. A systematic design methodology is introduced and used in the design of the refueling door mechanism. The design is divided into two sub-functions: door opening and actuation. Nine different mechanism concepts are created for the door opening function and eight different concepts are created for the actuation function. Pugh decision matrix method is used to evaluate and select the most feasible options. Six experienced engineers scored the option set, resultantly two concepts for the door opening and three concepts for the actuation sub-function are selected. Kinematic synthesis of these concepts is performed and used to determine the upper and lower bounds during optimization. Kinematic and force analysis of the concepts are performed and utilized for the constraints and cost function calculations of the optimization algorithm. Multi-objective Genetic Algorithm optimization technique is used to optimize the parameters of the selected mechanisms. The best mechanism for each sub-function is selected and combined to reach the final design. It was shown that through optimization, the required input torque decreased approximately 20% for the door opening mechanism and the required input force decreased approximately 42% for the actuation mechanism when compared to the graphical synthesis results

A comparative study of the standart surgical technique versus mini-ıncision in the treatment of Carpal Tunnel Syndrome

Amaç: Median sinirin el bileği düzeyindeki tuzak nöropatisi olan karpal tünel sendromunun (KTS) sağaltımında farklı cerrahi teknikler bildirilmiştir. Bu çalışmada KTS olgularında 2 farklı cerrahi teknik kullanılarak uygulanan sağaltımın sonuçları karşılaştırılmıştır. Yöntem: ılk guruptaki 11 olgunun 12 eline standart teknik ile cerrahi dekompresyon uygulanmış, ikinci guruptaki 10 olgunun 12 elinde ise mini insizyon yöntemi uygulanmıştır. Bulgular: Postoperatif izlem süresi, komplikasyon sıklığı, klinik ve elektronörofizyolojik bulgular yönünden değerlendirildiğinde iki gurup arasında X ve Fisher'in exact testleri ile istatistiksel olarak anlamlı bir fark olmadığı belirlenmiştir. Sonuç: Bu sonuçlar bize KTS cerrahisinde kullanılan standart ve mini insizyon tekniklerinin birbirlerine üstünlüklerinin olmadığını düşündürmüştür.Aim: Various surgical treatment alternatives exist for carpal tunnel syndrome which is the the entrapment of the median nerve at the wrist level. In this study two different surgical techniques were comparatively evaluated in terms oftime needed forpostoperative follow-up, complications, clinical and electrodiagnostic improvement. Method: Surgical decompression utilising the standard technique was used in 12 hands of the 11 patients in the first group and the mini-incision technique was employed in 12 hands of the 10 patients in the second group. Results: No statistical difference in any one of the above mentioned parameters was found with the X2 and Fisher's exacttests. Conclusion: Thus, we conclude that neither of the two techniques utilised for carpal tunnel syndrome surgery can be considered superior to the other

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London