A path following algorithm for mobile robots

This paper considers path following control for a robotic platform. The vehicle used for the experiments is a specially designed robotic platform for performing autonomous weed control. The platform is four-wheel steered and four-wheel driven. A diesel engine powers the wheels via a hydraulic transmission. The robot uses a Real Time Kinematic Differential Global Positioning System to determine both position and orientation relative to the path. The deviation of the robot to the desired path is supplied to two high level controllers minimizing the orthogonal distance and orientation to the path. Wheel angle setpoints are determined from inversion of the kinematic model. At low level each wheel angle is controlled by a proportional controller combined with a Smith predictor. Results show the controller performance following different paths shapes including a step, a ramp, and a typical headland path. A refined tuning method calculates controller settings that let the robot drive as much as possible along the same path to its setpoint, but also limit the gains at higher speeds to prevent the closed loop system to become unstable due to the time delay in the system. Mean, minimum and maximum orthogonal distance errors while following a straight path on a paving at a speed of 0.5 m/s are 0.0, -2.4 and 3.0 cm respectively and the standard deviation is 1.2 cm. The control method for four wheel steered vehicles presented in this paper has the unique feature that it enables control of a user definable position relative to the robot frame and can deal with limitations on the wheel angles. The method is very well practical applicable for a manufacturer: all parameters needed are known by the manufacturer or can be determined easily, user settings have an easy interpretation and the only complex part can be supplied as a generic software modul

MCDA stakeholder workshops

Within the CONFIDENCE project, comprehensive methods have been developed for better support of decision making under uncertain conditions, mainly by use of Multi Criteria Decision Analysis (MCDA). While MCDA in general was available for use in the radiological crisis management community, no method of analysing uncertain conditions and supporting robust decision making under these conditions was available. During the CONFIDENCE project, the existing MCDA tool was improved and enhanced to deal with these requirements. For providing solid and reliable decision support for such a situation as a radiological emergency, the evaluation of decision-support tools by the stakeholders and their feedback is important, especially when considering their heterogeneous background caused by e.g. living in different countries. Therefore, several stakeholder panels in different countries were organized to include the end users’ opinions and to assure the usability of the final tool

Path following with a robotic platform

This paper considers path following control for a four-wheel steered robotic platform. The vehicle used for the experiments is a specially designed robotic platform for performing autonomous weed control. The robot uses RTK- DGPS to determine both position and orientation relative to the path. The deviation of the robot to the desired path is supplied to a high level controller that determines the setpoints of the wheel angles and wheel speeds. At low level each wheel angle is controlled by a P controller combined with a Smith predictor. Results are presented of a preliminary navigation test on a paving

Domestic ventilation rates, indoor humidity and dust mite allergens : are our homes causing the asthma pandemic?

This paper is concerned with historical changes in domestic ventilation rates, relative humidity and the associated risk of house dust mite colonization. A controlled trial evaluated allergen and water vapour control measures on the level of house dust mite (HDM) Der p1 allergen and indoor humidity, concurrently with changes in lung function in 54 subjects who completed the protocol. Mechanical heat recovery ventilation units significantly reduced moisture content in the active group, while HDM allergen reservoirs in carpets and beds were reduced by circa 96%. Self reported health status confirmed a significant clinical improvement in the active group. The study can form the basis for assessing minimum winter ventilation rates that can suppress RH below the critical ambient equilibrium humidity of 60% and thus inhibit dust mite colonization and activity in temperate and maritime in' uenced climatic regions

Un nouveau test de la spectroscopie translationnelle: la prédissociation rotationnelle de l'état X1Sigma de HeH+.

peer reviewedWe reported the experiment on the accurate measurement of the kinetic energy released during the predissociation of HeH+ ions into the fragments H+ and He. This experiment was carried out on two machines specially designed for this purpose. The new results differ from those of the original experiment and agree now very well with the theoretical predictions

Specialist versus primary care prostate cancer follow-up:A process evaluation of a randomized controlled trial

Background: A randomized controlled trial (RCT) is currently comparing the effectiveness of specialist- versus primary care-based prostate cancer follow-up. This process evaluation assesses the reach and identified constructs for the implementation of primary care-based follow-up. Methods: A mixed-methods approach is used to assess the reach and the implementation through the Consolidated Framework for Implementation Research. We use quantitative data to evaluate the reach of the RCT and qualitative data (interviews) to indicate the perspectives of patients (n = 15), general practitioners (GPs) (n = 10), and specialists (n = 8). Thematic analysis is used to analyze the interview transcripts. Results: In total, we reached 402 (67%) patients from 12 hospitals and randomized them to specialist- (n = 201) or to primary care-based (n = 201) follow-up. From the interviews, we identify several advantages of primary care- versus specialist-based follow-up: it is closer to home, more accessible, and the relationship is more personal. Nevertheless, participants also identified challenges: guidelines should be implemented, communication and collaboration between primary and secondary care should be improved, quality indicators should be collected, and GPs should be compensated. Conclusion: Within an RCT context, 402 (67%) patients and their GPs were willing to receive/provide primary care-based follow-up. If the RCT shows that primary care is equally as effective as specialist-based follow-up, the challenges identified in this study need to be addressed to enable a smooth transition of prostate cancer follow-up to primary care. Netherlands Trial Registry, Trial NL7068 (NTR7266)

Co‐designing the Cabriotraining : a training for transdisciplinary teams

Accessible summary The research was conducted by a team of researchers. Some of the researchers have experience of living with a disability. The researchers created training for other research teams that include experts by experience. The training has six parts. To decide what happened in the training, the researchers read articles and asked the research teams they trained about what problems they had and what they wanted to know about. The article tells why and how the training was made. It also says what training is needed for researchers with and without disabilities to learn and work together in a way that feels safe and useful. In developing and providing the training, it was very crucial to search for a safe and welcome space for all people involved (Figure 8). As we don't know what is "safe" for the other, this means we have to search together, in respect and with enough time to get to know each other. Background Researchers collected questions and needs for training from 10 inclusive research projects in the Netherlands. Based on literature research and the information collected, six training modules were developed. Researchers sought to learn how to develop and provide training and coaching to inclusive teams on organising collaboration in the different stages of their research projects. Method An iterative training development process to support inclusive research projects was initiated by a research duo backed by a transdisciplinary team including researchers, trainers and designers. Some members of the team have experiential knowledge based on living with a disability. Results Literature research resulted in four guiding theories, including Universal Design for Learning, Derrida's concept of Hospitality, post-materialist theory looking at agency as an assemblage, and Romiszowski's model situated within Instructional Design theory. Insights gained during development of the training modules are documented with text, figures and vignettes. A core finding was the need to add "Level Zero" to Romiszowski's model: a collective term created for all the interacting issues trainers had to consider because of research group diversity. Conclusions Hospitality formed the heart of "Level Zero." Creating a failure-free space for learning is an important pre-condition for the development and organisation of training. Training can inspire exploration and reflection on collaboration and can illuminate how to conduct research within transdisciplinary teams. Essential practices included working with nonverbal research methods, as these are (more) fit for purpose when including the knowledge of experts by experience and incorporating practice- and stakeholder-based knowledge

The future of the CDM: same same, but differentiated?

Policy-makers and scientists have raised concerns about the functioning of the Clean Development Mechanism (CDM), in particular regarding its low contribution to sustainable development, unbalanced regional and sectoral distribution of projects, and its limited contribution to global emission reductions. Differentiation between countries or project types has been proposed as a possible way forward to address these problems. An overview is provided of the different ways in which CDM differentiation could be implemented. The implications for the actors involved in the CDM are analysed, along with a quantitative assessment of the impacts on the carbon market, using bottom-up marginal abatement cost curves. The discounting of CDM credits, quota systems, or differentiated eligibility of countries could help to address several of the concerns raised. Preferential treatment may also make a limited contribution to achieving the aims of CDM differentiation by increasing opportunities for under-represented host countries. The impact on the carbon market appears to be limited for most options

The role of cardiovascular magnetic resonance imaging and computed tomography angiography in suspected non-ST-elevation myocardial infarction patients:Design and rationale of the CARdiovascular Magnetic rEsoNance imaging and computed Tomography Angiography (CARMENTA) trial

BackgroundAlthough high-sensitivity cardiac troponin (hs-cTn) substantially improves the early detection of myocardial injury, it lacks specificity for acute myocardial infarction (MI). In suspected non–ST-elevation MI, invasive coronary angiography (ICA) remains necessary to distinguish between acute MI and noncoronary myocardial disease (eg, myocarditis), unnecessarily subjecting the latter to ICA and associated complications. This trial investigates whether implementing cardiovascular magnetic resonance (CMR) or computed tomography angiography (CTA) early in the diagnostic process may help to differentiate between coronary and noncoronary myocardial disease, thereby preventing unnecessary ICA.Study DesignIn this prospective, single-center, randomized controlled clinical trial, 321 consecutive patients with acute chest pain, elevated hs-cTnT, and nondiagnostic electrocardiogram are randomized to 1 of 3 strategies: (1) CMR, or (2) CTA early in the diagnostic process, or (3) routine clinical management. In the 2 investigational arms of the study, results of CMR or CTA will guide further clinical management. It is expected that noncoronary myocardial disease is detected more frequently after early noninvasive imaging as compared with routine clinical management, and unnecessary ICA will be prevented. The primary end point is the total number of patients undergoing ICA during initial admission. Secondary end points are 30-day and 1-year clinical outcome (major adverse cardiac events and major procedure-related complications), time to final diagnosis, quality of life, and cost-effectiveness.ConclusionThe CARMENTA trial investigates whether implementing CTA or CMR early in the diagnostic process in suspected non–ST-elevation MI based on elevated hs-cTnT can prevent unnecessary ICA as compared with routine clinical management, with no detrimental effect on clinical outcome