TY - JOUR A1 - Lauterbach, Helge A. A1 - Borrmann, Dorit A1 - Heß, Robin A1 - Eck, Daniel A1 - Schilling, Klaus A1 - Nüchter, Andreas T1 - Evaluation of a Backpack-Mounted 3D Mobile Scanning System JF - Remote Sensing N2 - Recently, several backpack-mounted systems, also known as personal laser scanning systems, have been developed. They consist of laser scanners or cameras that are carried by a human operator to acquire measurements of the environment while walking. These systems were first designed to overcome the challenges of mapping indoor environments with doors and stairs. While the human operator inherently has the ability to open doors and to climb stairs, the flexible movements introduce irregularities of the trajectory to the system. To compete with other mapping systems, the accuracy of these systems has to be evaluated. In this paper, we present an extensive evaluation of our backpack mobile mapping system in indoor environments. It is shown that the system can deal with the normal human walking motion, but has problems with irregular jittering. Moreover, we demonstrate the applicability of the backpack in a suitable urban scenario. KW - man-portable mapping KW - backpack mobile mapping KW - SLAM KW - mobile laser scanning KW - personal laser scanning Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126247 VL - 7 IS - 10 ER - TY - JOUR A1 - Hamouda, Khaled A1 - Oezkur, Mehmet A1 - Sinha, Bhanu A1 - Hain, Johannes A1 - Menkel, Hannah A1 - Leistner, Marcus A1 - Leyh, Rainer A1 - Schimmer, Christoph T1 - Different duration strategies of perioperative antibiotic prophylaxis in adult patients undergoing cardiac surgery: an observational study JF - Journal of Cardiothoracic Surgery N2 - Background All international guidelines recommend perioperative antibiotic prophylaxis (PAB) should be routinely administered to patients undergoing cardiac surgery. However, the duration of PAB is heterogeneous and controversial. Methods Between 01.01.2011 and 31.12.2011, 1096 consecutive cardiac surgery patients were assigned to one of two groups receiving PAB with a second-generation cephalosporin for either 56 h (group I) or 32 h (group II). Patients’ characteristics, intraoperative data, and the in-hospital follow-up were analysed. Primary endpoint was the incidence of surgical site infection (deep and superficial sternal wound-, and vein harvesting site infection; DSWI/SSWI/VHSI). Secondary endpoints were the incidence of respiratory-, and urinary tract infection, as well as the mortality rate. Results 615/1096 patients (56,1%) were enrolled (group I: n = 283 versus group II: n = 332). There were no significant differences with regard to patient characteristics, comorbidities, and procedure-related variables. No statistically significant differences were demonstrated concerning primary and secondary endpoints. The incidence of DSWI/SSWI/VHSI were 4/283 (1,4%), 5/283 (1,7%), and 1/283 (0,3%) in group I versus 6/332 (1,8%), 9/332 (2,7%), and 3/332 (0,9%) in group II (p = 0,76/0,59/0,63). In univariate analyses female gender, age, peripheral arterial obstructive disease, operating-time, ICU-duration, transfusion, and respiratory insufficiency were determinants for nosocomial infections (all ≤ 0,05). Subgroup analyses of these high-risk patients did not show any differences between the two regimes (all ≥ 0,05). Conclusions Reducing the duration of PAB from 56 h to 32 h in adult cardiac surgery patients was not associated with an increase of nosocomial infection rate, but contributes to reduce antibiotic resistance and health care costs. KW - nosocomial infection KW - cardiac surgery KW - antibiotic prophylaxis Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-124977 VL - 10 IS - 25 ER - TY - JOUR A1 - Gageik, Nils A1 - Benz, Paul A1 - Montenegro, Sergio T1 - Obstacle Detection and Collision Avoidance for a UAV with Complementary Low-Cost Sensors JF - IEEE Access N2 - This paper demonstrates an innovative and simple solution for obstacle detection and collision avoidance of unmanned aerial vehicles (UAVs) optimized for and evaluated with quadrotors. The sensors exploited in this paper are low-cost ultrasonic and infrared range finders, which are much cheaper though noisier than more expensive sensors such as laser scanners. This needs to be taken into consideration for the design, implementation, and parametrization of the signal processing and control algorithm for such a system, which is the topic of this paper. For improved data fusion, inertial and optical flow sensors are used as a distance derivative for reference. As a result, a UAV is capable of distance controlled collision avoidance, which is more complex and powerful than comparable simple solutions. At the same time, the solution remains simple with a low computational burden. Thus, memory and time-consuming simultaneous localization and mapping is not required for collision avoidance. KW - infrared KW - collision avoidance KW - autonomous KW - UAV KW - quadrocopter KW - obstacle detection KW - quadrotor KW - distance measurement KW - ultrasonic autonomous aerial vehicles KW - helicopters KW - infrared detectors Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125481 N1 - (c) 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works VL - 3 ER - TY - JOUR A1 - Toepfer, Martin A1 - Corovic, Hamo A1 - Fette, Georg A1 - Klügl, Peter A1 - Störk, Stefan A1 - Puppe, Frank T1 - Fine-grained information extraction from German transthoracic echocardiography reports JF - BMC Medical Informatics and Decision Making N2 - Background Information extraction techniques that get structured representations out of unstructured data make a large amount of clinically relevant information about patients accessible for semantic applications. These methods typically rely on standardized terminologies that guide this process. Many languages and clinical domains, however, lack appropriate resources and tools, as well as evaluations of their applications, especially if detailed conceptualizations of the domain are required. For instance, German transthoracic echocardiography reports have not been targeted sufficiently before, despite of their importance for clinical trials. This work therefore aimed at development and evaluation of an information extraction component with a fine-grained terminology that enables to recognize almost all relevant information stated in German transthoracic echocardiography reports at the University Hospital of Würzburg. Methods A domain expert validated and iteratively refined an automatically inferred base terminology. The terminology was used by an ontology-driven information extraction system that outputs attribute value pairs. The final component has been mapped to the central elements of a standardized terminology, and it has been evaluated according to documents with different layouts. Results The final system achieved state-of-the-art precision (micro average.996) and recall (micro average.961) on 100 test documents that represent more than 90 % of all reports. In particular, principal aspects as defined in a standardized external terminology were recognized with f 1=.989 (micro average) and f 1=.963 (macro average). As a result of keyword matching and restraint concept extraction, the system obtained high precision also on unstructured or exceptionally short documents, and documents with uncommon layout. Conclusions The developed terminology and the proposed information extraction system allow to extract fine-grained information from German semi-structured transthoracic echocardiography reports with very high precision and high recall on the majority of documents at the University Hospital of Würzburg. Extracted results populate a clinical data warehouse which supports clinical research. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125509 VL - 15 IS - 91 ER -