Showing papers by "Saab AB published in 2019"

OMSimulator – Integrated FMI and TLM-based Co-simulation with Composite Model Editing and SSP

Abstract: OMSimulator is an FMI-based co-simulation tool and recent addition to the OpenModelica tool suite. It supports large-scale simulation and virtual prototyping using models from multiple sources utilizing the FMI standard. It is integrated into OpenModelica but also available stand-alone, i.e., without dependencies to Modelicaspecific models or technology. OMSimulator provides an industrial-strength open-source FMI-based modelling and simulation tool. Input/output ports of FMUs can be connected, ports can be grouped to buses, FMUs can be parameterized and composed, and composite models can be exported according to the (preliminary) SSP (System Structure and Parameterization) standard. Efficient FMIbased simulation is provided for both model-exchange and co-simulation. TLM-based tool connection is provided for a range of applications, e.g., Adams, Simulink, Beast, Dymola, and OpenModelica. Moreover, optional TLM (Transmission Line Modelling) domain-specific connectors are also supported, providing additional numerical stability to co-simulation. An external API is available for use from other tools and scripting languages such as Python and Lua. The paper gives an overview of the tool functionality, compares with related work, and presents experience from industrial usage.

Comparison of the Rayleigh and K-Distributions for Application in Incoherent Change Detection

Abstract: The aim of this letter is to compare two incoherent change-detection algorithms for target detection in low-frequency ultrawideband (UWB) synthetic aperture radar (SAR) images. The considered UWB SAR operates in the frequency range from 20 to 90 MHz. Both approaches employ a likelihood ratio test according to the Neyman–Pearson criterion. First, the bivariate Rayleigh probability distribution is used to implement the likelihood ratio test function. This distribution is well known and has been used for change-detection algorithms in low-frequency UWB SAR with good results. Aiming to minimize the false alarm rate and taking into consideration that low-frequency UWB SAR images have high resolution compared to the transmitted wavelength, the second approach implements the test by using a bivariate K-distribution. This distribution has scale and shape parameters that can be used to adjust it to the data. No filter is applied to the data set images, and the results show that with a good statistical model, it is not needed to rely on filtering the data to decrease the number of false alarms. Therefore, we can have a better tradeoff between resolution and detection performance.

Fighter pilots' teamwork: a descriptive study

Abstract: The execution of teamwork varies widely depending on the domain and task in question. Despite the considerable diversity of teams and their operation, researchers tend to aim for unified theories and models regardless of field. However, we argue that there is a need for translation and adaptation of the theoretical models to each specific domain. To this end, a case study was carried out on fighter pilots and it was investigated how teamwork is performed in this specialised and challenging environment, with a specific focus on the dependence on technology for these teams. The collaboration between the fighter pilots is described and analysed using a generic theoretical model for effective teamwork from the literature. The results show that domain-specific application and modification is needed in order for the model to capture fighter pilot's teamwork. The study provides deeper understanding of the working conditions for teams of pilots and gives design implications for how tactical support systems can enhance teamwork in the domain. Practitioner summary: This article presents a qualitative interview study with fighter pilots based on a generic theoretical teamwork model applied to the fighter domain. The purpose is to understand the conditions under which teams of fighter pilots work and to provide guidance for the design of future technological aids.

Technology transfer as a part of the business – inter-organizational transfer strategies based on experiences of aircraft production

Abstract: Purpose The purpose of this paper is through a literature study and a study of the Saab offset cases to identify strategies to increase inter-organizational transfer capability. Design/methodology/approach This paper is based on a literature study and a study of three of Saab’s offset cases and Saab’s process for technology transfer. Findings This study has identified inter-organizational transfer strategies based on the importance of the hierarchy of decision-making and the change from capacity transfers to capability transfers in offset business. The type of performance goals set in the business agreement decides how to realize the transfer. The hierarchy of decision-making creates a need to align the understanding of the performance goals between the different parts of the organization, which affect the plans for how to transfer knowledge between the organizational as well as the individual levels. To reach the performance goals of the technology transfer, there needs to be a balance between the disseminative capability of the sender and the absorptive capability of the receiver. Research limitations/implications This study is based on a single case within a relatively unique industry with an offset perspective and production transfers. Therefore, there is also a need for future studies to confirm the identified relationships within outsourcing/offset within other industries and other types of transfers. Originality/value A change from capacity transfers to capability transfers in both outsourcing/offshoring and offset business indicates that more research should be placed on the disseminative capacity of the sender. The literature review revealed that the disseminative capacity of the sender has been the subject of less research than the absorptive capacity of the receiver.

Excellence in Exploratory Testing: Success Factors in Large-Scale Industry Projects

Abstract: Based on interviews with 20 interviewees from four case study companies, this paper presents a list of key factors that enable efficient and effective exploratory testing of large-scale software systems. The nine factors are grouped into four themes: “The testers’ knowledge, experience and personality”, “Purpose and scope”, “Ways of working” and “Recording and reporting”. According to the interviewees, exploratory testing is a more creative way to work for the testers, and was therefore considered to make better use of the testers. Exploratory testing was also described as a good way to test system-wide and to test large-scale systems, especially exploratory testing with an end-user perspective. The identified key factors were confirmed by a series of follow-up interviews with the 20 interviewees and a cross-company workshop with 14 participants. This strengthens the generalizability of the findings, supporting that the list of key factors can be applied to projects in a large segment of the software industry. This paper also presents the results from a systematic literature review including 129 publications related to exploratory testing. No publication were found that summarizes the key factors that enable efficient and effective exploratory testing, which supports the novelty of the findings.

Microwave Heating as a Method to Improve Sanitation of Sewage Sludge in Wastewater Plants

Abstract: For long-term sustainable agriculture, it is critical that we recycle nutrition to the soil that it came from. One important source is sewage sludge, but it must be sanitized from undesired pathogens before it may be spread on arable land. One common method today is deposition in about six months or more. Not only is such a long deposition-time costly due to the required storage-space, in the future usage of the method is likely to be more restricted from a regulatory perspective. To heat up sewage-sludge is a known method to speed up the sanitation process. However, achieving an even guaranteed temperature is not easy with porous sewage sludge. This is mainly due to the limited heat conductivity of the sludge. Microwaves at a frequency of 2.45 GHz have a penetration depth of a few centimeters and therefore has an advantage compared to other heating methods which only heats the surface. In the proposed system, the sewage sludge is continuously processed through a series of microwave cavities. The pathogen removal effectiveness was studied for different exposure settings, e.g., conveyor speed and applied microwave power in each cavity.

Big bangs and small pops: on critical cyclomatic complexity and developer integration behavior

Abstract: Continuous integration is believed by many to improve software quality, including cyclomatic complexity. In this paper an exploratory study investigates the relationship between continuous integration behavior among developers and the cyclomatic complexity --- particularly at critical levels --- of the source code they commit, as a correct understanding of the consequences of a software development practice, particularly one as popular as continuous integration, is of crucial importance to industry professionals when deciding on improvement efforts. It is found that developer behavior differs significantly, as does their knowledge and awareness of cyclomatic complexity as a concept. We find that even though large commits ("big bangs") contribute proportionately slightly more to cyclomatic complexity, the effect is much less pronounced for critical cyclomatic complexity. It is also found that complex code tends to overlap with high levels of change activity, and that some developers deliberately change their integration behavior in the face of such hotspots, as a strategy to avoid merge conflicts.

Consistent Distributed Track Fusion Under Communication Constraints

Abstract: This paper addresses the problem of retrieving consistent estimates in a distributed network where the communication between the nodes is constrained such that only the diagonal elements of the covariance matrix are allowed to be exchanged. Several methods are developed for preserving and/or recovering consistency under the constraints imposed by the communication protocol. The proposed methods are used in conjunction with the covariance intersection method and the estimation performance is evaluated based on information usage and consistency. The results show that among the proposed methods, consistency can be preserved equally well at the transmitting node as at the receiving node.

Fast forming of multistacked UD prepreg using a high‐pressure process

Abstract: In this article, the opportunities of fast forming of multistacked UD prepreg when using high-pressure forming were examined in an experimental study. Forming is often considered a bottleneck in ma ...

T-matrix method for closely adjacent obstacles

Abstract: This paper presents a novel method to calculate the T-matrix for two non-spherical obstacles positioned close to each other, where the individual circumscribed spheres intersect. This is achieved by translating the obstacles coordinate systems, using translation matrices for spherical vector waves. The new circumscribing spheres enables the obstacles to be positioned close to each other. A new total T-matrix of the two-obstacle system can then be calculated using methods for composite particles, i.e., the superposition T-matrix method. This total T-matrix will generally be larger than the original ones, depending on the sizes of the circumscribing spheres used in the coordinate translation procedure. However, it is shown that the total T-matrix can be truncated after transformation to a common origin, without degrading the accuracy. The total truncated T-matrix is only slightly larger than the original individual ones. The method is demonstrated for electromagnetic scattering simulations of two metallic disks, closely adjacent to each other. (Less)

A Wide Coverage S-Band Array with Dual Polarized Connected Bowtie Antenna Elements

Abstract: A low profile dual polarized bowtie antenna element is studied for an S-band (3 GHz) wide-scan application in a large-scale (nearly an infinitely large) uniformly excited phased array. The study shows that the array with such elements, when connected, is capable of scanning up to ±75° at E-plane and ±15° at H-plane for horizontal and vertical polarizations respectively. The bandwidth of the infinite array with such elements across these scan angles is 10% and 25% for the active reflection coefficient of −10 dB and −5 dB respectively.

Lempel-Ziv-Markov Chain Algorithm Modeling using Models of Computation and ForSyDe

Abstract: The data link is considered a critical function of modern aircraft, responsible for exchanging information to the ground and communicating to other aircraft. Nowadays, the increasing amount of exchanged data and information brings the need for network usage optimization. In this sense, data compression is considered a key approach to make data packages size smaller. Regarding the fact that avionics systems are safety-critical, it is fundamental not losing data nor performance during the compression procedures. In this context, manufacturers and regulatory agencies usually follow DO-178C guidance. Targeting model-based embedded design guidelines, DO-178C includes a supplement document, named DO-331. In this paper, we describe a widely used data compression algorithm, the Lempel-Ziv-Markov Chain algorithm (LZMA). Regarding formal model-based design, we argue that the synchronous dataflow model of computation captures the algorithm behavior more directly. The Formal System Design (ForSyDe) methodology is used to model the LZMA.

Test activities in the continuous integration and delivery pipeline

Abstract: Based on 25 interviews with participants from four case study companies that develop large-scale software embedded systems, this paper presents the Test Activity Stakeholders (TAS) model. The TAS model shows how the continuous integration and delivery pipeline can be designed to include test activities that support four stakeholder interests: “Check changes,” “Secure stability,” “Measure progress,” and “Verify compliance.” The model is developed to show how each of the stakeholder interests are best supported by unit/component tests or system tests, by automated testing or manual testing and by tests executed in simulated environments or on real hardware. The TAS model may serve as a starting point for companies when evaluating and designing their continuous integration and delivery pipeline. The validation of the TAS model included twelve individuals from three case study companies. The validation showed that the TAS model is actionable and useful in practice, enabling the identification of stakeholders and showing where improvement efforts should be focused in order to support all stakeholder interests in the continuous integration and delivery pipeline.

Continuous Architecture: Towards the Goldilocks Zone and Away from Vicious Circles

Abstract: This paper identifies three improvement areas related to system design and architecture, where an organization can change to better support continuous integration and continuous delivery: “The product's architecture”, “Ways to work with system design and architecture”, and “The role of the architect”. The three improvement areas are based on a literature review, two series of interviews and a cross-company workshop with three case-study companies. Furthermore, the paper proposes three actionable strategies corresponding to the three identified improvement areas: “Systems with a modular and loosely coupled architecture”, “A balanced approach where system design and architecture is focused on the system's most important characteristics”, and “Architects shifting perspective from control to facilitation”.

Geometric compensation of convex forming tools for successful final processing in concave cure tools – An experimental study

Abstract: To enable shimless composite part assembly it is desired to manufacture composite spars in concave, female tools. However, due to restricted access this process is often associated with a high degr ...

Agility is responsiveness to change: An essential definition.

Abstract: There is some ambiguity of what agile means in both research and practice. Authors have suggested a diversity of different definitions, through which it is difficult to interpret what agile really is. The concept, however, exists in its implementation through agile practices. In this vision paper, we argue that adopting an agile approach boils down to being more responsive to change. To support this claim, we relate agile principles, practices, the agile manifesto, and our own experiences to this core definition. We envision that agile transformations would be, and are, much easier using this definition and contextualizing its implications.

What software engineering can learn from research on affect in social psychology

Abstract: Social psychology researchers have, traditionally, focused on the construct of thinking rather than on feeling. Since the beginning of the 21st century, social science researchers have, however, increasingly explored the effects of affect. Their work has repeatedly recognized that affects play a crucial role in determining people's behavior. In this short paper, we argue that software engineering studies on affect would benefit from using more of the knowledge that social science researchers have acquired. Without accounting for their findings, we risk re-inventing the wheel. Also, without a profound understanding of the complex interplay between social context and affect, we risk creating overly simplistic solutions that might have considerable long-term adverse effects for software engineers.

An aircraft secondary control system for aircraft and a method for operating the system

Abstract: The present invention regards a system and a method for providing a motion of an aircraft secondary control member (111, 611) incrementally in steps. An aircraft secondary control system comprises a rod arrangement (109, 609) of a driving actuator (115, 615), configured for performing the motion. The rod arrangement (109, 609) is coupled to the aircraft secondary control member (111, 611) via a linkage arrangement (117, 617). The driving actuator (115, 615) comprises a first engagement and disengagement device (119, 619) of a piston body (107, 607) and comprises a second engagement and disengagement device (125, 625), each of which being configured for alternately and/or simultaneously engaging said rod arrangement (109, 609). The piston body (107, 607) is arranged in a cylinder body (105, 605) and is configured to make a working stroke from a first position (P1) to a second position (P2). There is provided a method of engaging the piston body (107, 607) to the rod arrangement (109, 609); moving the piston body (107, 607) together with the rod arrangement (109, 609) a distance corresponding with said working stroke; engaging the second engagement and disengagement device (125, 625) to the rod arrangement (109, 609); disengaging the first engagement and disengagement device (119, 619) from the rod arrangement (109, 609); retracting the piston body (107) from the second position (P2) to the first position (P1) and repeating the previous method steps for providing said motion.

Tailored information provision for multinational naval operations

Abstract: In multinational defence operations, either EU or NATO driven, the exchange of surveillance and reconnaissance data and information is an essential aspect to be able to act promptly. Coordinated processes and agreements are the basis, distribution architectures, services, interfaces and formats the prerequisite. In the NATO context, the Joint ISR (Intelligence, Surveillance and Reconnaissance) process supports the execution of surveillance and reconnaissance tasks. The Coalition Shared Data (CSD) concept and the associated specifications, interfaces and information models defined in STANAGs (Standardization Agreements), as well as the NATO ISR Interoperability Architecture (NIIA), facilitate the exchange of information based on the described processes. The EU uses CISE (Common Information Sharing Environment) and MARSUR (Maritime Surveillance), which are based on NATO-like principles. Within this frame, the OCEAN2020 (Open Cooperation for European mAritime awareNess) project, funded by the European Union's Preparatory Action on Defence Research and implemented by the European Defence Agency, sees 42 partners from 15 EU countries working to network future maritime surveillance and interdiction missions at sea integrating drones and unmanned submarines into fleet operations. Here data and information will be integrated in a comprehensive (maritime) picture of developing situations for military commanders on different unit levels. Maritime Operation Centers (MOC) on a national and EU level can be connected with operational commands/units to exchange information. With its remote-acting units equipped with only temporary and often narrow-band network connections, the Navy places particular demands on architecture (s). This paper focusses on the challenge to define flexible architectures for maritime operations.

Short range radar cohabitation

Abstract: The present invention relates to a method for a continuous arbitrary waveform radar configured for transmitting and receiving signals over a selected communication band. The method comprises: generating the radar transmit signal with a waveform having a non-monotonic frequency change, modifying the waveform to obtain at least one spectral notch and isolating reception and transmission by cancellation. Each spectral notch at a selectable frequency with a selectable bandwidth, and the waveform is modified to maintain the spectral density of the transmit radar signal.

Triple Modular Redundancy based on Runtime Reconfiguration and Formal Models of Computation

Abstract: Runtime reconfiguration is one promising way to mitigate for increased failure rate and thereby it fulfills safety requirements needed for future safety-critical avionics systems. In case of a hardware fault, the system is able, during runtime, to automatically detect such fault and redirect the functionality from the defective module to a new safe reconfigured module, thus minimizing the effects of hardware faults. This paper introduces a high level abstraction architecture for safety-critical systems with runtime reconfiguration using the triple modular redundancy and the synchronous model of computation. A modeling strategy to be used in the design phase supported by formal models of computation is also addressed in the paper. The triple modular redundancy technique is used for detecting faults where, in case of inconsistency in one of the three processors caused by a fault, a new processor is reconfigured based on a software or hardware reconfiguration, and it assumes the tasks of the faulty processor. The introduced strategy considers that no other fault occurs during the reconfiguration of a new processor.

Thermal Characteristics of Vertically-Integrated GaN/SiC-on-Si Assemblies: A Comparative Study

Abstract: This work investigates the thermal characteristics of a vertically-stacked, heterogeneously-integrated assembly intended for millimetre-wave communications systems. The assembly combines materials that enable the generation of high output power as well as high degree of integration for improved performance, and vertical integration of the different materials enables a compact footprint. Suitability of thermal solutions based on metal pillars, solder balls, and ball grid arrays (BGA) is investigated. Both ideal, fully-populated arrays of interconnects and partially-filled ones more suitable for practical implementations are considered using theoretical calculations and numerical thermal simulations. With the assumptions used, simulation results show that arrays of Cu pillars and large solder bumps with a pitch of 150 µm provide good thermal performance also with a simplified grid and reduced number of interconnects. In the current geometry, the most important locations for the pillars and bumps are near the heat sources, and the use of a rim of interconnects around the assembly perimeter can reduce the temperature by several degrees - even when the majority of the other interconnects is focused beneath the heat sources.

Formal Design, Co-Simulation and Validation of a Radar Signal Processing System

Abstract: With the ever increasing complexity in safety-critical and performance-demanding application domains such as automotive and avionics, the costs of designing, producing and especially testing systems does not scale well for the next generation of applications. One example is the active electronically scanned array (AESA) antenna signal processing chain, which is currently out-of-reach from consumer products but rather part of a few exclusive hi-tech appliances. To cope with the associated complexity of such systems, we propose a design flow starting from a high-level formal modeling language which captures and exposes important design properties to enable their systematic exploitation for the purpose of simulation, analysis and synthesis towards cost-efficient implementations. We demonstrate the capabilities of this approach by providing a compact yet expressive description of the AESA signal processing chain, generate automatic test-cases to verify the conformity of model with design specifications, synthesize a part of it to VHDL and co-simulate the generated artifact to validate its correctness.

Intentional Electromagnetic Interference and Critical Infrastructure

Abstract: Intentional Electromagnetic Interference or IEMI is the result of maliciously created electromagnetic disturbances in sensitive electronic systems. Modern infrastructure such as power supply, wireless communication networks, banking system, and transportation networks are dependent on civilian-off-the-shelf (COTS) equipment for its uninterrupted and reliable operations. Even though COTS equipment are tested for electromagnetic compatibility as per pre-defined un-intentional electromagnetic environment and test methods, intentionally created electromagnetic disturbances creates a lot of uncertainty in the proper functioning of critical COTS elements of the infrastructure. Infrastructure is interconnected widely distributed systems and there are several ports where substantial electromagnetic energy can be coupled intentionally by saboteurs and once coupled these disturbances travel through the interconnected system and cause breakdown at one or more weak links. It is probable that some of these breakdowns may lead to widespread disruption of critical infrastructure, such as power supply blackouts, financial service shutdown or disruption in railway network due to signal failures. Due to its inherent nature, EM attacks to civilian infrastructure may happen anonymously and repeatedly without detection. Protection of civilian critical infrastructure against the effects of IEMI has received a lot of attention recently from the EMC community. This article reviews the work done around the world with special emphasis on the work done in Sweden [e.g; 1–5].

A stabilization arrangement for stabilization of an antenna mast

Abstract: A stabilization arrangement (10) for stabilizing an antenna mast (3), comprising an antenna mast (3) and a gyroscopic stabilizer device (12), wherein the gyroscopic stabilizer device (12) in turn comprises a flywheel (11), a flywheel axis (14), wherein the flywheel (11) is arranged about the flywheel axis (14), and a gimbal structure (13), wherein the flywheel (11) is suspended in the gimbal structure (13) and the gimbal structure (13) is configured to permit flywheel precession or tilting about at least one gimbal output axis (16). The gyroscopic stabilizer device (12) is fixedly arranged in connection to a first end portion (31) of the antenna mast (3) and the antenna mast (3) is fastenable to a supporting structure at a second end portion (32) of the antenna mast (3), wherein the gyroscopic stabilizer device (12) is configured to reduce movements in a plane perpendicular to the extension of the antenna mast (3).

What software engineering can learn from research on affect in social psychology

Abstract: Social psychology researchers have, traditionally, focused on the construct of thinking rather than on feeling. Since the beginning of the 21st century, social science researchers have, however, increasingly explored the effects of affect. Their work has repeatedly recognized that affects play a crucial role in determining people's behavior. In this short paper, we argue that software engineering studies on affect would benefit from using more of the knowledge that social science researchers have acquired. Without accounting for their findings, we risk re-inventing the wheel. Also, without a profound understanding of the complex interplay between social context and affect, we risk creating overly simplistic solutions that might have considerable long-term adverse effects for software engineers.

Airframe Sealing Automation Using Snake-robot

Abstract: The work described herein have had the objective of carrying out a technical-economic feasibility study of a snake-robot for sealant application in an aircraft fuselage. The execution of the project brought knowledge related to the design and development of robots, constrained Cartesian trajectory generation, optimization methods for inverse kinematics computation, collaborative robotics and 3D simulations besides experiments related to aircraft components and application of sealants in the fuselage. Concerning the technical feasibility of the project, the solution proposed proved to be an adequate solution for the proposed task. The sealant application trajectories in fillets (union of two plates of the fuselage) and fasteners were tested, being all well executed by the robot in a virtual environment, without collisions and without relevant complications. All the trajectories used for the evaluation were taken from the test framework provided by Saab and respecting the process specifications described for this task. Economical evaluation of ROM (Rough Order of Magnitude) gives a result showing fairly good pay-back time although the potentials would be even better with a lower cost. A list of commercial components for the manufacturing of the snake robot was specified, such as: motors, reducers, vision system, components for programming and controlling the robot (drivers, software and robot interface with the user) etc. It is important to mention that, despite the design of the robot drivers, the CAD model developed here needs further detailing for fabrication purposes. Structural analysis must be carried out in the structure and, after any changes are made, evaluations and corrections must be done. A study about the dimension and mass reductions of an existing sealant dispenser was carried out, where the cartridge and the sealant application valve were chosen to be coupled directly to the robotic arm. In general, all activities were executed according to the proposed schedule. The project presented a very high potential and could be applied not only to the aeronautical industry (which was the main objective of the present work), but also to other fields of the industry. Therefore, a continuation of this project is highly recommended, such that the proposed snake robot can be manufactured and physically tested.

Method of combusting aluminium and system therefor

Abstract: A system and method of combusting aluminium comprising i) feeding aluminium wire to a substantially oxygen-free furnace comprising a. a first low-temperature section in communication with b. a second high-temperature section ii) forming aluminium particles with an average particle size ranging from 1 μιη to 200 μιη from said aluminium wire in said first section iii) feeding water and/or steam to said first and/or second section to provide an oxidizer for oxidizing said aluminium particles in the second section iv) conveying aluminium particles from the first section to the second section v) oxidizing said aluminium particles in the presence of steam in said second section.

Dynamically with tiltable magazine and method for launching countermeasures

Abstract: A dispenser for storing and launching countermeasures from an aircraft, comprising an elongate body provided with at least one launch opening where the countermeasures are stored in cartridges, where the cartridges are interconnect to each other in a slidable manner, and where the cartridges are adapted to be tilted by a tilting means to a selected angle, such that the openings of the cartridges can be directed in a selected direction. The advantage of the invention is that a countermeasure can be directed in a desired angle before it is launched.