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Henriksson M.,Swedish Defence Research Agency | Olofsson T.,Swedish Defence Research Agency | Olofsson T.,Combitech AB | Gronwall C.,Swedish Defence Research Agency | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Tomographic signal processing is used to transform multiple one-dimensional range profiles of a target from different angles to a two-dimensional image of the object. The range profiles are measured by a time-correlated single-photon counting (TCSPC) laser radar system with approximately 50 ps range resolution and a field of view that is wide compared to the measured objects. Measurements were performed in a lab environment with the targets mounted on a rotation stage. We show successful reconstruction of 2D-projections along the rotation axis of a boat model and removal of artefacts using a mask based on the convex hull. The independence of spatial resolution and the high sensitivity at a first glance makes this an interesting technology for very long range identification of passing objects such as high altitude UAVs and orbiting satellites but also the opposite problem of ship identification from high altitude platforms. To obtain an image with useful information measurements from a large angular sector around the object is needed, which is hard to obtain in practice. Examples of reconstructions using 90 and 150° sectors are given. In addition, the projection of the final image is along the rotation axis for the measurement and if this is not aligned with a major axis of the target the image information is limited. There are also practical problems to solve, for example that the distance from the sensor to the rotation centre needs to be known with an accuracy corresponding to the measurement resolution. The conclusion is that that laser radar tomography is useful only when the sensor is fixed and the target rotates around its own axis. © 2012 SPIE. Source

Andersson H.,Saab | Herzog E.,Saab | Johansson G.,Combitech AB | Johansson O.,Linkoping University
Systems Engineering | Year: 2010

A Unified Modeling Language/Systems Modeling Language (UML/SysML) subset was the modeling notation selected for an aerospace systems engineering project at Saab Aerosystems. In this paper, the rationale for selecting UML/SysML is given, along with a description of the situation at the project planning stage regarding business conditions, method and tools support. The usage of use case, sequence, and activity diagrams are described as well as definition of functional chains with SysML. Furthermore, the connections to system implementation activities including code generation and simulation are discussed. The advantages and disadvantages of using UML/SysML from experience in an industrial context are reported. It is also described how UML/SysML is related to industrial research projects in the Model Based Systems Engineering (MBSE) methods and tools area. Introducing UML/SysML with a methodology and a supporting toolset in an operative organization require a clear strategy, including planning, just-in-time training, and mentor support. Finally, industrial needs for further development of SysML are discussed. © 2009 Wiley Periodicals, Inc. Source

Mattsson A.,Combitech AB
Proceedings - International Conference on Software Engineering | Year: 2010

Current techniques for modeling software architecture lacks support for the modeling of architectural design rules, i.e. rules defined by the architect that have to be followed in the detailed design. This is a problem in the context of Model-Driven Development in which it is assumed that major design artifacts are represented as formal or semi-formal models. The PhD project presented in this paper addresses this problem by the definition of a method for modeling architectural design rules in a form that is easily interpreted by developers. A tool for automatic validation of the design model against the architectural rules has also been developed. The method is designed to be easy to learn and use for both architects and developers. As a part of the PhD project the method is also currently validated in a case study on an industrial development project. © 2010 ACM. Source

Ryberg A.-B.,Combitech AB | Ryberg A.-B.,Linkoping University | Backryd R.D.,Linkoping University | Nilsson L.,Linkoping University
Engineering with Computers | Year: 2015

Automotive companies continuously strive to design better products faster and more cheaply using simulation models to evaluate every possible aspect of the product. Multidisciplinary design optimization (MDO) can be used to find the best possible design taking into account several disciplines simultaneously, but it is not yet fully integrated within automotive product development. The challenge is to find methods that fit company organizations and that can be effectively integrated into the product development process. Based on the characteristics of typical automotive structural MDO problems, a metamodel-based MDO process intended for large-scale applications with computationally expensive simulation models is presented and demonstrated in an example. The process is flexible and can easily fit into existing organizations and product development processes where different groups work in parallel. The method is proven to be efficient for the discussed example and improved designs can also be obtained for more complex industrial cases with comparable characteristics. © 2014, Springer-Verlag London. Source

Andersson M.,Chalmers University of Technology | Andersson M.,Combitech AB | Pipkorn B.,Chalmers University of Technology | Pipkorn B.,Autoliv | Lovsund P.,Chalmers University of Technology
Traffic Injury Prevention | Year: 2013

Objective: The purpose of this study was to evaluate and propose improvements to the injury mitigation systems, in near-side impacts, for 6 common sitting positions of young adolescents using a previously validated model.Methods: The evaluation was made by using a model of a complete passenger car, including head and thorax-pelvis air bags, which was impacted laterally by a barrier in 2 load cases. The SID-IIs finite element model was used for the evaluations and was seated in 6 different positions in the rear outboard seat: the nominal anthropomorphic test device (ATD) position, 1 inboard position, 3 outboard positions, and 1 braking (forward) position. These positions have previously been identified as common sitting positions in awake and asleep children. The studied dependent variables were head injury criterion (HIC) 36, resultant head linear acceleration, resultant head rotational acceleration, chest viscous criterion, and chest deflection.Results: The lowest head injury measures were seen in the braking positions and in the nominal ATD position, and the highest were seen in the inboard and outboard positions. The lowest chest injury measures were recorded in the inboard and nominal ATD positions, and the highest were recorded in the outboard and braking positions. The occupant in the outboard positions interfered with the air bags during their deployment. The occupant in inboard and braking positions tended to push the curtain air bag over the windowsill.Conclusions: Studies that investigate the injury mitigation effects in common sitting positions, beyond the nominal ATD position, are essential to highlight means to provide improved and robust safety for child occupants. This study was based on the SID-IIs 5th percentile female, which has very similar anthropometry to a 50th percentile 12-year-old. Therefore, the conclusions of this study are applicable to many 11-year-olds up to young adolescents, as well as to small females.The outboard and inboard positions of this study resulted in the highest head injury measures. Although all of the injury measures were only slightly higher than the nominal position, the trends suggest that, in near-side impacts, these positions should be discouraged. The extensively outboard positions resulted in unfavorable air bag positioning during deployment. The inboard position resulted in head strikes further forward of the nominal one; the curtain air bags need inflated cells at all locations of head strike. © 2013 Copyright Taylor and Francis Group, LLC. Source

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