EVALUATION OF STEREO ALGORITHMS FOR OBSTACLE DETECTION WITH FISHEYE LENSES

For autonomous navigation of micro aerial vehicles (MAVs), a robust detection of obstacles with onboard sensors is necessary in order to avoid collisions. Cameras have the potential to perceive the surroundings of MAVs for the reconstruction of their 3D structure. We equipped our MAV with two fisheye stereo camera pairs to achieve an omnidirectional field-of-view. Most stereo algorithms are designed for the standard pinhole camera model, though. Hence, the distortion effects of the fisheye lenses must be properly modeled and model parameters must be identified by suitable calibration procedures. In this work, we evaluate the use of real-time stereo algorithms for depth reconstruction from fisheye cameras together with different methods for calibration. In our experiments, we focus on obstacles occurring in urban environments that are hard to detect due to their low diameter or homogeneous texture

OMNIDIRECTIONAL PERCEPTION FOR LIGHTWEIGHT UAVS USING A CONTINUOUSLY ROTATING 3D LASER SCANNER

Many popular unmanned aerial vehicles (UAV) are restricted in their size and weight, making the design of sensory systems for these robots challenging. We designed a small and lightweight continuously rotating 3D laser scanner – allowing for environment perception in a range of 30 m in almost all directions. This sensor it well suited for applications such as 3D obstacle detection, 6D motion estimation, localization, and mapping. We aggregate the distance measurements in a robot-centric grid-based map. To estimate the motion of our multicopter, we register 3D laser scans towards this local map. In experiments, we compare the laser-based ego-motion estimate with ground-truth from a motion capture system. Overall, we can build an accurate 3D obstacle map and can estimate the vehicle's trajectory by 3D scan registration

TOWARDS MULTIMODAL OMNIDIRECTIONAL OBSTACLE DETECTION FOR AUTONOMOUS UNMANNED AERIAL VEHICLES

Limiting factors for increasing autonomy and complexity of truly autonomous systems (without external sensing and control) are onboard sensing and onboard processing power. In this paper, we propose a hardware setup and processing pipeline that allows a fully autonomous UAV to perceive obstacles in (almost) all directions in its surroundings. Different sensor modalities are applied in order take into account the different characteristics of obstacles that can commonly be found in typical UAV applications. We provide a complete overview on the implemented system and present experimental results as a proof of concept

Health economic analyses in medical nutrition: a systematic literature review

Stefan Walzer,1,2 Daniel Droeschel,1,3 Mark Nuijten,4 Hélène Chevrou-Séverac5 1MArS Market Access and Pricing Strategy GmbH, Weil am Rhein, Germany; 2State University Baden-Wuerttemberg, Loerrach, Germany; 3Riedlingen University, SRH FernHochschule, Riedlingen, Germany; 4Ars Accessus Medica BV, Amsterdam, the Netherlands, 5Nestlé Health Science, Vevey, Switzerland Background: Medical nutrition is a specific nutrition category either covering specific dietary needs and/or nutrient deficiency in patients or feeding patients unable to eat normally. Medical nutrition is regulated by a specific bill in Europe and in the US, with specific legislation and guidelines, and is provided to patients with special nutritional needs and indications for nutrition support. Therefore, medical nutrition products are delivered by medical prescription and supervised by health care professionals. Although these products have existed for more than 2 decades, health economic evidence of medical nutrition interventions is scarce. This research assesses the current published health economic evidence for medical nutrition by performing a systematic literature review related to health economic analysis of medical nutrition. Methods: A systematic literature search was done using standard literature databases, including PubMed, the Health Technology Assessment Database, and the National Health Service Economic Evaluation Database. Additionally, a free web-based search was conducted using the same search terms utilized in the systematic database search. The clinical background and basis of the analysis, health economic design, and results were extracted from the papers finally selected. The Drummond checklist was used to validate the quality of health economic modeling studies and the AMSTAR (A Measurement Tool to Assess Systematic Reviews) checklist was used for published systematic reviews. Results: Fifty-three papers were identified and obtained via PubMed, or directly via journal webpages for further assessment. Thirty-two papers were finally included in a thorough data extraction procedure, including those identified by a “gray literature search” utilizing the Google search engine and cross-reference searches. Results regarding content of the studies showed that malnutrition was the underlying clinical condition in most cases (32%). In addition, gastrointestinal disorders (eg, surgery, cancer) were often analyzed. In terms of settings, 56% of papers covered inpatients, whereas 14 papers (44%) captured outpatients, including patients in community centers. Interestingly, in comparison with the papers identified overall, very few health economic models were found. Most of the articles were modeling analyses and economic trials in different design settings. Overall, only eight health economic models were published and were validated applying the Drummond checklist. In summary, most of the models included were carried out to quite a high standard, although some areas were identified for further improvement. Of the two systematic health economic reviews identified, one achieved the highest quality score when applying the AMSTAR checklist. Conclusion: The reasons for finding only a few modeling studies but quite a large number of clinical trials with health economic endpoints, might be different. Until recently, health economics has not been required for reimbursement or coverage decisions concerning medical nutrition interventions. Further, there might be specifics of medical nutrition which might not allow easy modeling and consequently explain the limited uptake so far. The health economic data on medical nutrition generated and published is quite ample. However, it has been primarily based on database analysis and clinical studies. Only a few modeling analyses have been carried out, indicating a need for further research to understand the specifics of medical nutrition and their applicability for health economic modeling. Keywords: systematic review, medical nutrition, health economic

Health economics evidence for medical nutrition: are these interventions value for money in integrated care?

Stefan Walzer,1,2 Daniel Droeschel,1,3 Mark Nuijten,4 Hélène Chevrou-Séverac5 1MArS Market Access and Pricing Strategy GmbH, Weil am Rhein, Germany; 2State University Baden Wuerttemberg, Loerach, Germany; 3Riedlingen University, SRH FernHochschule, Riedlingen, Germany; 4Ars Accessus Medica BV, Jisp, Amsterdam, the Netherlands; 5Nestlé Health Science, Vevey, Switzerland Background: Health care decision-makers have begun to realize that medical nutrition plays an important role in the delivery of care, and it needs to be seen as a sole category within the overall health care reimbursement system to establish the value for money. Indeed, improving health through improving patients' nutrition may contribute to the cost-effectiveness and financial sustainability of health care systems. Medical nutrition is regulated by a specific bill either in Europe or in the United States, which offers specific legislations and guidelines (as provided to patients with special nutritional needs) and indications for nutritional support. Given that the efficacy of medical nutrition has been proven, one can wonder whether the heterogeneous nature of its coverage/reimbursement across countries might be due to the lack of health-related economic evidence or value-for-money of nutritional interventions. This paper aims to address this knowledge gap by performing a systematic literature review on health economics evidence regarding medical nutrition, and by summarizing the results of these publications related to the value for money of medical nutrition interventions. Methods: A systematic literature search was initiated and executed based on a predefined search protocol following the population, intervention, comparison, and outcomes (PICO) criteria. Following the systematic literature search of recently published literature on health economics evidence regarding medical nutrition, this study aims to summarize the results of those publications that are related to the value for money of medical nutrition interventions. The evaluations were conducted by analyzing different medical nutrition according to their indications, the economic methodology or perspective adopted, the cost source and utility measures, selected efficiency measures, as well as the incremental cost-effectiveness ratio. Results: A total of 225 abstracts were identified for the detailed review, and the data were entered into a data extraction sheet. For the abstracts that finally met the predefined inclusion criteria (n=53), full-text publications were obtained via PubMed, subito, or directly via each journal's Webpage for further assessment. After a detailed review of the full text articles, 34 publications have been qualified for a thorough data extraction procedure. When differentiating the resulting articles in terms of their settings, 20 studies covered inpatients, whereas 14 articles covered outpatients, including patients in community centers. When reviewing the value-for-money evaluations, the indications showed that the different results were mostly impacted by the different perspectives adopted and the comparisons that were made. In order to draw comprehensive conclusions, the results were split according to the main indications and diseases. Discussion: The systematic literature search has shown that there is not only an interest in health economics and its application in medical nutrition, but that there is a lot of ongoing research in this area. Based on the underlying systematic analysis, it has been shown that medical nutrition interventions offer value for money in the different health care settings, particularly for the specific disease areas that have been pointed out. Conclusion: Based on the systematic literature search that was performed, it was shown that medical nutrition interventions offer value for money in the different health care settings. Although medical nutrition has been the topic of some health economic analyses, the usual willingness to pay threshold used in health care rarely was applied. Often, these products are either directly part of a lump sum in the financing system (for example, diagnosis-related groups), or they are covered as out-of-pocket payments by patients directly. More research would be necessary to better understand how medical nutrition interventions can be optimally funded by the health care system, given the clinical value they bring to patients in their recovery process. Keywords: systematic review, medical nutrition, health economic