| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Arshad, Hamed, 1987, et al.
(författare)
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Attribute-based encryption with enforceable obligations
- 2023
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Ingår i: Journal of Cryptographic Engineering. - Heidelberg : Springer. - 2190-8508 .- 2190-8516. ; 13, s. 343-371
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Tidskriftsartikel (refereegranskat)abstract
- Attribute-based encryption (ABE) is a cryptographic mechanism that provides fine-grained access control to encrypted data, which can thus be stored in, e.g., public clouds. However, ABE schemes lack the notion of obligations, which is common in attribute-based access control systems such as eXtensible Access Control Markup Language and Usage Control. Obligations are used to define and enforce extra constraints that happen before approving or denying an access request. In this paper, we propose OB-ABE, a system for extending any classical ABE with enforceable obligations. Our system architecture has as core component trusted hardware enclaves, implemented with SGX, used for enforcing obligations. We employ ProVerif to formally model OB-ABE and verify its main property called "enforceable obligations," i.e., if a message is encrypted along with an obligation, then the message can be decrypted only after enforcing the attached obligation. OB-ABE has two more properties: (i) OB-ABE is a "conservative extension" of the underlying ABE scheme, preserving its security properties; (ii) OB-ABE is "backward compatible" in the sense that any ciphertext produced by an ABE scheme can be decrypted by its extended OB-ABE version, and moreover, a ciphertext produced by an OB-ABE scheme can be decrypted by its underlying ABE scheme provided that the ciphertext does not have obligations attached. We also implement in C using Intel SGX a prototype of an OB-ABE extending the well-known ciphertext-policy ABE.
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| 3. |
- Jeppson, Kjell, 1947, et al.
(författare)
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Theory of a room-temperature silicon quantum dot device as a sensitive electrometer
- 2004
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Ingår i: Journal of Applied Physics. - Melville, NY : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 95:1, s. 323-326
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Tidskriftsartikel (refereegranskat)abstract
- We consider theoretically the use of a room-temperature silicon quantum dot based device for electrometer applications. The low power device includes two split gates that quantize the electronic energy levels in the emitter and collector regions. The base consists of a silicon quantum dot buried in silicon dioxide. The small size of the dotand quantization of the states in the leads combined to allow the device to operate at room temperature. The nonlinear current-voltage characteristics can be significantly altered by small changes to the potential of the split gates. Power dissipation in the device therefore changes with the split gate voltage, and this can be exploited in electrometerapplications. A simple model of the power dissipated when the device is part of a microwave resonant inductor-resistor-capacitor tank circuit suggests that large changes indevice power can be achieved by changing the gate voltage, thereby forming a measurable signal. We also demonstrate that the power dissipation in the device changes as the base width is varied, and that the current through the device increases exponentially with a decrease in base width. (©2004 American Institute of Physics)
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| 4. |
- Eriksson, Martin, 1970, et al.
(författare)
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Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton
- 2009
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Ingår i: Applied and Environmental Microbiology. - Washington, D.C. : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 75:4, s. 897-906
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Tidskriftsartikel (refereegranskat)abstract
- This study analyzes psbA gene sequences, predicted D1 protein sequences, species relative abundance, and pollution-induced community tolerance in marine periphyton communities exposed to the antifouling compound Irgarol 1051. The mechanism of action of Irgarol is the inhibition of photosynthetic electron transport at photosystem II by binding to the D1 protein. The metagenome of the communities was used to produce clone libraries containing fragments of the psbA gene encoding the D1 protein. Community tolerance was quantified with a short-term test for the inhibition of photosynthesis. The communities were established in a continuous flow of natural seawater through microcosms with or without added Irgarol. The selection pressure from Irgarol resulted in an altered species composition and an inducted community tolerance to Irgarol. Moreover, there was a very high diversity in the psbA gene sequences in the periphyton, and the composition of psbA and D1 fragments within the communities was dramatically altered by increased Irgarol exposure. Even though tolerance to this type of compound in land plants often depends on a single amino acid substitution (Ser(264)-> Gly) in the D1 protein, this was not the case for marine periphyton species. Instead, the tolerance mechanism likely involves increased degradation of D1. When we compared sequences from low and high Irgarol exposure, differences in nonconserved amino acids were found only in the so-called PEST region of D1, which is involved in regulating its degradation. Our results suggest that environmental contamination with Irgarol has led to selection for high-turnover D1 proteins in marine periphyton communities at the west coast of Sweden.
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| 5. |
- Henriksson, Jens, 1991, et al.
(författare)
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Towards Structured Evaluation of Deep Neural Network Supervisors
- 2019
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Ingår i: Proceedings - 2019 IEEE International Conference on Artificial Intelligence Testing, AITest 2019. - New York : Institute of Electrical and Electronics Engineers Inc.. - 9781728104928 ; 1
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Konferensbidrag (refereegranskat)abstract
- Deep Neural Networks (DNN) have improved the quality of several non-safety related products in the past years. However, before DNNs should be deployed to safety-critical applications, their robustness needs to be systematically analyzed. A common challenge for DNNs occurs when input is dissimilar to the training set, which might lead to high confidence predictions despite proper knowledge of the input. Several previous studies have proposed to complement DNNs with a supervisor that detects when inputs are outside the scope of the network. Most of these supervisors, however, are developed and tested for a selected scenario using a specific performance metric. In this work, we emphasize the need to assess and compare the performance of supervisors in a structured way. We present a framework constituted by four datasets organized in six test cases combined with seven evaluation metrics. The test cases provide varying complexity and include data from publicly available sources as well as a novel dataset consisting of images from simulated driving scenarios. The latter we plan to make publicly available. Our framework can be used to support DNN supervisor evaluation, which in turn could be used to motive development, validation, and deployment of DNNs in safety-critical applications.
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| 6. |
- Pelliccione, Patrizio, 1975, et al.
(författare)
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Beyond connected cars: A systems of systems perspective
- 2020
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Ingår i: Science of Computer Programming. - Amsterdam : Elsevier BV. - 0167-6423 .- 1872-7964. ; 191
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Tidskriftsartikel (refereegranskat)abstract
- The automotive domain is rapidly changing in the last years. Among the different challenges OEMs (i.e. the vehicle manufacturers) are facing, vehicles are evolving into systems of systems. In fact, over the last years vehicles have evolved from disconnected and “blind” systems to systems that are (i) able to sense the surrounding environment and (ii) connected with other vehicles, the city, pedestrians, cyclists, etc. Future transportation systems can be seen as a System of Systems (SoS). In an SoS, constituent systems, i.e. the units that compose an SoS, can act as standalone systems, but their cooperation enables new emerging and promising scenarios. While this trend creates new opportunities, it also poses a risk to compromise key qualities such as safety, security, and privacy. In this paper we focus on the automotive domain and we investigate how to engineer and architect cars in order to build them as constituents of future transportation systems. Our contribution is an architectural viewpoint for System of Systems, which we demonstrate based on an automotive example. Moreover, we contribute a functional reference architecture for cars as constituents of an SoS. This reference architecture can be considered as an imprinting for the implementations that would be devised in specific projects and contexts. We also point out the necessity for a collaboration among different OEMs and with other relevant stakeholders, such as road authorities and smart cities, to properly engineer systems of systems composed of cars, trucks, roads, pedestrians, etc. This work is realized in the context of two Swedish projects coordinated by Volvo Cars and involving some universities and research centers in Sweden and many suppliers of the OEM, including Autoliv, Arccore, Combitech, Cybercom, Knowit, Prevas, ÅF-Technology, Semcom, and Qamcom.
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| 7. |
- Karlsson, Göran, 1954, et al.
(författare)
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Joint reasoning about gas solubility in water in modified versions of a virtual laboratory
- 2013
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Ingår i: 10th International Conference on Computer-Supported Collaborative Learning, CSCL 2013; Madison, WI; United States; 15 June 2013 through 19 June 2013. - : International Society of the Learning Sciences. - 1573-4552. ; 2, s. 283-284, s. 283-284
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Konferensbidrag (refereegranskat)abstract
- A virtual laboratory was designed to enable students to collaboratively discover the concept of gas solubility in water at different physiological conditions. The virtual laboratory was developed through a design experiment involving three successive versions with different guiding structures. Analysis of 13 dyads' reasoning about gas solubility in water revealed that the students' problem was to understand the concept of solubility of gases. It was also observed how the guiding structures within the three different versions influenced the students' reasoning about the concept.
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| 8. |
- Nilsson, Bertil, 1953-, et al.
(författare)
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A Stokes model with cavitation for the numerical simulation of hydrodynamic lubrication
- 2011
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Ingår i: International Journal for Numerical Methods in Fluids. - Chichester, Sussex : Wiley. - 0271-2091 .- 1097-0363. ; 67:12, s. 2015-2025
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Tidskriftsartikel (refereegranskat)abstract
- We present a cavitation model based on the Stokes equation and formulate adaptive finite element methods for its numerical solution. A posteriori error estimates and adaptive algorithms are derived, and numerical examples illustrating the theory are supplied, in particular with comparison to the simplified Reynolds model of lubrication.
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| 9. |
- Nilsson, Bertil, 1953-, et al.
(författare)
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Adaptive finite element methods for hydrodynamic lubrication with cavitation
- 2007
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Ingår i: International Journal for Numerical Methods in Engineering. - Chichester : John Wiley & Sons. - 0029-5981 .- 1097-0207. ; 72:13, s. 1584-1604
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Tidskriftsartikel (refereegranskat)abstract
- We present an adaptive finite element method for a cavitation model based on Reynolds' equation. A posteriori error estimates and adaptive algorithms are discussed, and numerical examples illustrating the theory are supplied.
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| 10. |
- Nilsson, Bertil, 1953-, et al.
(författare)
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Weak coupling of a Reynolds model and a Stokes model for hydrodynamic lubrication
- 2011
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Ingår i: International Journal for Numerical Methods in Fluids. - Chichester, Sussex : Wiley. - 0271-2091 .- 1097-0363. ; 66:6, s. 730-741
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Tidskriftsartikel (refereegranskat)abstract
- The Reynolds model is a reduced Stokes model, valid for narrow lubrication regions. In order to be able to handle locally non-narrow regions such as pits or grooves, often displaying rapid geometrical variations, there is a need to be able to transit to the more accurate Stokes model. A fundamental problem is how to couple the two models in a numerical simulation, preferably allowing for different meshes in the different domains. In this paper, we present a weak coupling method for Reynolds and Stokes models for lubrication computations, including the possibility of cavitation in the different regions. The paper concludes with a numerical example. Copyright (C) 2010 John Wiley & Sons, Ltd.
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