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The purpose of risk management in the development of safety-critical software is to eliminate or reduce harmful behaviour. In health-care it is essential to manage risk related to software due to its increased use in medical devices and other computer systems. This paper presents some of the experiences gained from an ongoing case study at a large hospital in Sweden. The study focuses on identific

In this paper we present a new class of MAC protocols for wireless LANs based on sharing of transmission intentions. We develop an example protocol implementation based on distributed, co-operative scheduling of data frames. Sched- ules are non-binding, requiring minimal negotiation between nodes. The protocol is implemented on top of standard 802.11 so that backwards compatibility with legacy nod

This paper presents the findings from a design study of a model-based framework for safety-critical software development, called SimPal. The objective of the study was to better understand the necessary properties of such a framework and to learn more about the challenges of realizing it. Our research approach can be labeled as design research, which means that we try to answer our research questi

Bioaerosols include bacterial cells and spores, viruses, pollen, fungi, algae, detritus, allergens and cell fragments. Bioaerosol particles are usually a small fraction of all aerosol particles in our surroundings, but their impact can be critical. They are a means for transmission of disease, they cause allergic reactions and they have effects on the global climate, ecology and biodiversity. This

This paper presents the hardware implementation of a wavelet based event detector for cardiac pacemakers. A high level energy estimation flow was applied to evaluate energy efficiency of standard-cell based designs, over several CMOS technology generations, from 180 to 65 nm, operated in the sub-threshold domain. The simulation results indicate a 65 nm low-leakage high-threshold (LL-HVT) CMOS tech

In this work we present a new low-power medium access scheme for sensor-type networks specifically with low traffic intensity. We call the proposed scheme DCW-MAC where ultra-low-power wake-up receivers are combined with optimal duty-cycled listening. First we introduce a framework for the analysis of energy consumption of the studied network type, then we use it to optimize the MAC scheme to achi

Analytical Multiple-Input Multiple-Output (MIMO) models are often attractive due to their low complexity when analyzing possibilities and limitations in the system. In this paper we outline a a possible dual link extension of an analytical MIMO channel model and investigate its suitability based on measurements of a dual link MIMO scenario. The extension is based on the correlation matrix distance

Popular Abstract in Swedish Immunförsvaret, som även kan benämnas immunsystemet, kan betraktas som ett organ som är utspritt i hela kroppen istället för samlat på ett ställe. Immunsystemet består av ett stort antal vita blodkroppar som finns i blodet, ute i vävnaderna, samt samlade i lymfkörtlar och mjälten. Immunsystemets uppgift är att försvara oss från yttre faror som virus och bakterier samt aThe small intestine contains a large number of T lymphocytes within the single-layered epithelium that separates the gut lumen from the lamina propria. These intraepithelial T lymphocytes have potent cytolytic and immunoregulatory capacities, thought to be important for fighting infections, neoplastic growth, and sustaining epithelial integrity. This thesis is based on three original articles wit

This paper highlights the issues of detecting Java concurrency bugs using static code analysis tools. Concurrency bugs are often hard to find because of interleaving threads and there is need to use static analysis tools to detect the concurrency bugs. In the literature review, we established that there are number of static analysis tools such as FindBugs, JLint and Chord, used in experiments to d

As average packet sizes in wireless networks shrink and data rates increase, the fundamental CSMA mechanism in the 802.11 protocol family is put under stress. With the emerg- ing 802.11ax standard, the carrier sensing mechanism is low- ering the efficiency of the protocol to the level of random access (ALOHA), and as future-generation 802.11 standards emerge, CSMA-based protocols will fall below t

In this paper we present an algorithm for finding low-weight multiples of polynomials over the binary field using coding theoretic methods. The code defined by the public polynomial is cyclic, allowing an attacker to search for any shift of the sought codeword. Therefore, a code with higher length and dimension is used, having a larger number of low-weight codewords. Additionally, since the degree of

The stochastic Lagrange wave model is a realistic alternative to the Gaussian linear wave model, which has been successfully used in ocean engineering for more than half a century. This paper presents the slope distributions and other characteristic distributions at level crossings for asymmetric Lagrange time waves, i.e. what can be observed at a fixed measuring station, thereby extending result

Aerosol particle samples were collected, and the particle size distribution was measured during 1 year at the Zeppelin station (474 m asl) on Svalbard. The chemical constituents, hygroscopicity, and cloud forming properties of the aerosol were analyzed. The aerosol contained mostly sulfate and nitrate during the summer, whereas from September to February the main components were sodium and chlorid

In the present study, natural and anthropogenic sources of particulate organic carbon (OCp) and elemental carbon (EC) have been quantified based on weekly filter samples of PM10 (particles with aerodynamic diameter < 10 mu m) collected at four Nordic rural background sites [Birkenes (Norway), Hyytiala (Finland), Vavihill (Sweden), Lille Valby, (Denmark)] during late summer (5 August-2 September 20

Particles in the atmosphere are of concern due to their toxic properties and effects on climate. In coastal areas, ship emissions can be a significant anthropogenic source. In this study we investigated the contribution from ship emissions to the total particle number and mass concentrations at a remote location. We studied the particle number concentration (12 to 490 nm in diameter), the mass con

Spatial data are crucial in disaster planning. However, because of the dynamic, urgent and uncertain nature of disasters, certain data and functionalities may be inaccessible to decision makers when they are required. Web service composition offers a possible solution whereby disaster planners can integrate spatial web services to generate new spatial data and functionalities, quickly, from existi

Particles containing soot, or black carbon, are generally considered to contribute to global warming. However, large uncertainties remain in the net climate forcing resulting from anthropogenic emissions of black carbon (BC), to a large extent due to the fact that BC is co-emitted with gases and primary particles, both organic and inorganic, and subject to atmospheric ageing processes. In this stu

A new class of stochastic field models is constructed using nested stochastic partial differential equations (SPDEs). The model class is computationally efficient, applicable to data on general smooth manifolds, and includes both the Gaussian Matérn fields and a wide family of fields with oscillating covariance functions. Nonstationary covariance models are obtained by spatially varying the parame