Robot path planning using a genetic algorithm

Robot path planning can refer either to a mobile vehicle such as a Mars Rover, or to an end effector on an arm moving through a cluttered workspace. In both instances there may exist many solutions, some of which are better than others, either in terms of distance traversed, energy expended, or joint angle or reach capabilities. A path planning program has been developed based upon a genetic algorithm. This program assumes global knowledge of the terrain or workspace, and provides a family of good paths between the initial and final points. Initially, a set of valid random paths are constructed. Successive generations of valid paths are obtained using one of several possible reproduction strategies similar to those found in biological communities. A fitness function is defined to describe the goodness of the path, in this case including length, slope, and obstacle avoidance considerations. It was found that with some reproduction strategies, the average value of the fitness function improved for successive generations, and that by saving the best paths of each generation, one could quite rapidly obtain a collection of good candidate solutions

A multi-sensor system for robotics proximity operations

Robots without sensors can perform only simple repetitive tasks and cannot cope with unplanned events. A multi-sensor system is needed for a robot to locate a target, move into its neighborhood and perform operations in contact with the object. Systems that can be used for such tasks are described

“I often have to explain to school staff what she needs”. School experiences of non-autistic siblings growing up with an autistic brother or sister

BACKGROUND: Recent autism research has evidenced a shift from psychological outcomes to contextualised approaches to understanding the varying needs of non autistic siblings of autistic children across different systems. Yet, there is limited research exploring the lived experiences of siblings in their school context. METHODS: First, a group of school aged sibling advisors worked with the first author to codesign research aims, methods and dissemination practices around the topic of the school experiences of siblings who grow up with an autistic brother or sister in the UK. Then, 28 school-aged siblings of autistic children completed adapted photo-elicitation interviews, to discuss their school experiences. A background questionnaire was also administered to their parents and carers. RESULTS: Thematic analysis was employed. The master themes included: (i) Impact of home experiences in schoolwork, including limited personal time and sleep disruptions (ii) Siblings’ school interactions impact on overall school experience, including a wide range of both typical and difficult experiences such as school day disruptions, (iii) Varied perceived levels of support and understanding, including emotional and/or educational support by family members and a sense of connectedness with peers and teachers who are autistic themselves or connected to someone with a diagnosis of autism. IMPLICATIONS: The results underline the ways home experiences can have an impact on school life of siblings, the positive contribution of the autistic school staff and/or staff who have an autistic family member and the need for an organisational culture of inclusivity and widespread acceptance and awareness around issues of neurodiversity. Our findings suggest several implications for school psychologists in core functions of the educational psychologists’ role including training, consultation, assessment, and whole school support. DATA AVAILABILITY STATEMENT: The datasets generated for this study are not readily available because they include sensitive data (photos of siblings’ houses, family members, personal objects, and school timetables). Requests to access the datasets should be directed to corresponding author

MARIE Measurements and Model Predictions of Solar Modulation of Galactic Cosmic Rays at Mars

Recent data from the MARIE (Martian Radiation Environment Experiment) instrument on board the 2001 Mars Odyssey spacecraft currently in Mars orbit are presented. It is shown that the short-term modulations of galactic cosmic rays (GCR) are well described by correlating the so lar modulation parameter, , with Earth-based neutron monitor counts using a 85-day time lag and the NASA Models - HZETRN (High Z and Energy Transport) and QMSFRG (Quantum Multiple Scattering theory of nuclear Fragmentation). The dose rates observed by the MARIE instrument are within 10% of the model calculations

A cross-sectional survey of cardiovascular health and lifestyle habits of hospital staff in the UK: Do we look after ourselves?

Background: A high prevalence of stress-related disorders is well known among healthcare professionals. We set out to assess the prevalence of cardiovascular risk factors and compliance with national dietary and physical activity recommendations in NHS staff in the UK with comparison between clinical and non-clinical staff, and national surveys. Design: A multi-centre cross-sectional study. Methods: A web-based questionnaire was developed to include anonymised data on demographics, job role, cardiovascular risk factors and diseases, dietary habits, physical activity and barriers towards healthy lifestyle. This was distributed to staff in four NHS hospitals via emails. Results: A total of 1158 staff completed the survey (response rate 13%) with equal distribution between the clinical and non-clinical groups. Most staff were aged 26–60 years and 79% were women. Half of the staff were either overweight or obese (51%) with no difference between the groups (P = 0.176), but there was a lower prevalence of cardiovascular risk factors compared to the general population. The survey revealed a low compliance (17%) with the recommended intake of five-a-day portions of fruit and vegetables, and that of moderate or vigorous physical activity (56%), with no difference between the clinical and non-clinical staff (P = 0.6). However, more clinical staff were exceeding the alcohol recommendations (P = 0.02). Lack of fitness facilities and managerial support, coupled with long working hours, were the main reported barriers to a healthy lifestyle. Conclusions: In this survey of UK NHS staff, half were found to be overweight or obese with a lower prevalence of cardiovascular risk factors compared to the general population. There was a low compliance with the five-a-day fruit and vegetables recommendation and physical activity guidelines, with no difference between the clinical and non-clinical staff

Toward an automated signature recognition toolkit for mission operations

Signature recognition is the problem of identifying an event or events from its time series. The generic problem has numerous applications to science and engineering. At NASA's Johnson Space Center, for example, mission control personnel, using electronic displays and strip chart recorders, monitor telemetry data from three-phase electrical buses on the Space Shuttle and maintain records of device activation and deactivation. Since few electrical devices have sensors to indicate their actual status, changes of state are inferred from characteristic current and voltage fluctuations. Controllers recognize these events both by examining the waveform signatures and by listening to audio channels between ground and crew. Recently the authors have developed a prototype system that identifies major electrical events from the telemetry and displays them on a workstation. Eventually the system will be able to identify accurately the signatures of over fifty distinct events in real time, while contending with noise, intermittent loss of signal, overlapping events, and other complications. This system is just one of many possible signature recognition applications in Mission Control. While much of the technology underlying these applications is the same, each application has unique data characteristics, and every control position has its own interface and performance requirements. There is a need, therefore, for CASE tools that can reduce the time to implement a running signature recognition application from months to weeks or days. This paper describes our work to date and our future plans

Ex vivo detection and characterization of early dental caries by optical coherence tomography and Raman spectroscopy.

Early dental caries detection will facilitate implementation of nonsurgical methods for arresting caries progression and promoting tooth remineralization. We present a method that combines optical coherence tomography (OCT) and Raman spectroscopy to provide morphological information and biochemical specificity for detecting and characterizing incipient carious lesions found in extracted human teeth. OCT imaging of tooth samples demonstrated increased light backscattering intensity at sites of carious lesions as compared to the sound enamel. The observed lesion depth on an OCT image was approximately 290 mm matching those previously documented for incipient caries. Using Raman microspectroscopy and fiber-optic- based Raman spectroscopy to characterize the caries further, spectral changes were observed in PO 42 vibrations arising from hydroxyapa- tite of mineralized tooth tissue. Examination of various ratios of PO 42 n 2 , n 3 , n 4 vibrations against the n 1 vibration showed consistent in- creases in carious lesions compared to sound enamel. The changes were attributed to demineralization-induced alterations of enamel crystallite morphology and/or orientation. OCT imaging is useful for screening carious sites and determining lesion depth, with Raman spectroscopy providing biochemical confirmation of caries. The com- bination has potential for development into a new fiber-optic diagnos- tic tool enabling dentists to identify early caries lesions with greater sensitivity and specificity. © 2005 Society of Photo-Optical Instrumentation Engi

Particle swarm optimization : understanding order-2 stability guarantees

This paper’s primary aim is to provide clarity on which guarantees about particle stability can actually be made. The particle swarm optimization algorithm has undergone a considerable amount of theoretical analysis. However, with this abundance of theory has come some terminological inconstancies, and as a result it is easy for a practitioner to be misguided by overloaded terminology. Specifically, the criteria for both order-1 and order-2 stability are well studied, but the exact definition of order-2 stability is not consistent amongst researchers. A consequence of this inconsistency in terminology is that the existing theory may in fact misguide practitioners instead of assisting them. In this paper it is theoretically and empirically demonstrated which practical guarantees can in fact be made about particle stability. Specifically, it is shown that the definition of order-2 stability which accurately reflects PSO behavior is that of convergence in second order moment to a constant, and not to zero.http://link.springer.combookseries/5582020-03-30hj2020Computer Scienc

Polymer electrolyte direct methanol fuel cells: an option for transportation applications

PEFCs most frequently considered for electric vehicles have been based on either hydrogen carried aboard, or steam-reforming of methanol on board to produce H2 + CO2. Direct methanol fuel cells (DMFCs), which use a liquid methanol fuel feed, completely avoid the complexity and weight penalties of the reformer, but have not been considered a serious option until recently, because of much lower power densities. Recent advances in DMFCs have been dramatic, however, with the DMFC reaching power densities which are significant fractions of those provided by reformate/air fuel cells. Use of established Pt-Ru anode electrocatalysts and Pt cathode electrocatalysts in polymer electrolyte DMFCs has resulted in enhanced DMFC performance, particularly when operated above 100 C and when catalyst layer composition and structure are optimized. The higher DMFC power densities recently achieved provide a new basis for considering DMFCs for transportation applications

HIV-1 Epidemic in the Caribbean Is Dominated by Subtype B

The molecular epidemiology of HIV-1 in the Caribbean has been described using partial genome sequencing; subtype B is the most common subtype in multiple countries. To expand our knowledge of this, nearly full genome amplification, sequencing and analysis was conducted.Virion RNA from sera collected in Haiti, Dominican Republic, Jamaica and Trinidad and Tobago were reverse transcribed, PCR amplified, sequenced and phylogenetically analyzed. Nearly full genomes were completed for 15 strains; partial pol was done for 67 strains. All but one of the 67 strains analyzed in pol were subtype B; the exception was a unique recombinant of subtypes B and C collected in the Dominican Republic. Of the nearly full genomes of 14 strains that were subtype B in pol, all were subtype B from one end of the genome to the other and not inter-subtype recombinants. Surprisingly, the Caribbean subtype B strains clustered significantly with each other and separate from subtype B from other parts of the pandemic.The more complete analysis of HIV-1 from 4 Caribbean countries confirms previous research using partial genome analysis that the predominant subtype in circulation was subtype B. The Caribbean strains are phylogenetically distinct from other subtype B strains although the biological meaning of this finding is unclear