| 1. |
- Skoglund, Mikael, et al.
(author)
-
A case study on regression test suite maintenance in system evolution
- 2004
-
In: 20TH IEEE INTERNATIONAL CONFERENCE ON SOFTWARE MAINTENANCE, PROCEEDINGS. - 0769522130 ; , s. 438-442
-
Conference paper (peer-reviewed)abstract
- When a system is maintained, its automated test suites must also be maintained to keep the tests up to date. Even though practice indicates that test suite maintenance can be very costly we have seen few studies considering the actual efforts for maintenance of test-ware. We conducted a case study on an evolving system with three updated versions, changed with three different change strategies. Test suites for automated unit and functional tests were used for regression testing the extended applications. With one change strategy more changes were made in the tests code than in the system that was tested, and with another strategy no changes were needed for the unit tests to work.
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| 2. |
- Almotairi, Fawaz, et al.
(author)
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Swallowing Dysfunction in Adult Patients with Chiari I Malformation
- 2018
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In: Journal of Neurological Surgery Part B-Skull Base. - : Georg Thieme Verlag KG. - 2193-6331 .- 2193-634X. ; 79:6, s. 606-613
-
Journal article (peer-reviewed)abstract
- Background Swallowing difficulties have been reported in patients with Chiari I malformation (CMI) with a prevalence of 4 to 47%, but existing evidence is based only on case reports. We aimed to prospectively study swallowing function in adult patients with CMI before and 3 months after surgical decompression. Methods We included all adult patients diagnosed with CMI from September 2015 to October 2017 who underwent a planned surgery at Sahlgrenska University Hospital, Sweden. The patients were offered the opportunity to participate in and undergo an assessment consisting of the "Watson Dysphagia Scale (WDS)" and "EORTC QLQ-OG25" written questionnaires in addition to videofluoroscopic examination of swallowing (VFS) before and 3 months after surgery. Demographic data and comorbidities were recorded. Results Eleven patients were included, nine of which underwent both pre- and postoperative evaluations. Four patients (36%) reported varying degrees of swallowing complaints (meanWDS score, 16). In two of these, there was substantial penetration of contrast material into the laryngeal vestibule on VFS, and in the other two patients, minor swallowing disturbances were observed. Borderline deviations from normal VFS findings were also found in three asymptomatic patients. Although not all VFS deviations completely disappeared after surgery, the patients reported no remaining symptoms. Conclusion Symptoms of dysphagia and objective abnormalities on VFS are not uncommon in CMI patients. Surgery has the potential to remedy underlying causes of dysphagia, thereby relieving its symptoms. OULEZZ AO, 1985, JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, V9, P1033
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| 3. |
- Andersson, Fredrik, et al.
(author)
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A Portable Douglas Bag System
- 2015
-
In: Congress Proceedings. - 9789513962166 ; , s. 59-
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Conference paper (peer-reviewed)
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| 4. |
- Axelsson, Jakob, et al.
(author)
-
Quality assurance in software ecosystems : A systematic literature mapping and research agenda
- 2015. - 11
-
In: Journal of Systems and Software. - : Elsevier BV. - 0164-1212 .- 1873-1228. ; 114, s. 69-81
-
Journal article (peer-reviewed)abstract
- Abstract Software ecosystems are becoming a common model for software development in which different actors cooperate around a shared platform. However, it is not clear what the implications are on software quality when moving from a traditional approach to an ecosystem, and this is becoming increasingly important as ecosystems emerge in critical domains such as embedded applications. Therefore, this paper investigates the challenges related to quality assurance in software ecosystems, and identifies what approaches have been proposed in the literature. The research method used is a systematic literature mapping, which however only resulted in a small set of six papers. The literature findings are complemented with a constructive approach where areas are identified that merit further research, resulting in a set of research topics that form a research agenda for quality assurance in software ecosystems. The agenda spans the entire system life-cycle, and focuses on challenges particular to an ecosystem setting, which are mainly the results of the interactions across organizational borders, and the dynamic system integration being controlled by the users.
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| 5. |
- Bengtsson, Torbjörn, et al.
(author)
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The periodontal pathogen Porphyromonas gingivalis cleaves apoB-100 and increases the expression of apoM in LDL in whole blood leading to cell proliferation
- 2008
-
In: Journal of Internal Medicine. - : Institutionen för medicin och hälsa. - 0954-6820 .- 1365-2796. ; 263:5, s. 558-571
-
Journal article (peer-reviewed)abstract
- Objective: Several studies support an association between periodontal disease and atherosclerosis with a crucial role for the pathogen Porphyromonas gingivalis. This study aims to investigate the proteolytic and oxidative activity of P. gingivalis on LDL in a whole blood system by using a proteomic approach and analyze the effects of P. gingivalis-modifed LDL on cell proliferation.Methods: The cellular effects of P. gingivalis in human whole blood were assessed using lumi-aggregometry analyzing reactive oxygen species (ROS) production and aggregation. Blood was incubated for 30 min with P. gingivalis, whereafter LDL was isolated and a proteomic approach was applied to examine protein expression. LDL-oxidation was determined by analyzing the formation of protein carbonyls. The effects of P. gingivalis-modifed LDL on fibroblast proliferation were studied using the MTS-assay.Results: Incubation of whole blood with P. gingivalis caused an extensive aggregation and ROS-production, indicating platelet and leukocyte activation. LDL prepared from the bacteria-exposed blood showed an increased protein oxidation, elevated levels of apoM and formation of two apoB-100 N-terminal fragments. P. gingivalis-modified LDL markedly increased the growth of fibroblasts. Inhibition of gingipain R suppressed the modification of LDL by P. gingivalis.Conclusions: The ability of P. gingivalis to change the protein expression and the proliferative capacity of LDL may represent a crucial event in periodontitis-associated atherosclerosis.
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| 6. |
- Cavarec, Baptiste, et al.
(author)
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A Learning-Based Approach to Address Complexity-Reliability Tradeoff in OS Decoders
- 2020
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - : IEEE Computer Society. ; , s. 689-692
-
Conference paper (peer-reviewed)abstract
- In this paper, we study the tradeoffs between complexity and reliability for decoding large linear block codes. We show that using artificial neural networks to predict the required order of an ordered statistics based decoder helps in reducing the average complexity and hence the latency of the decoder. We numerically validate the approach through Monte Carlo simulations.
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| 7. |
- Ekström, Thomas, 1961-, et al.
(author)
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An optimised defence supply system : Defining the principles
- 2017
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In: NOFOMA 2017 - The 29th NOFOMA Conference. - Lund : Lund University. - 9789177533375 ; , s. 761-763
-
Conference paper (other academic/artistic)abstract
- PurposeThe purpose of this paper is to describe the first step in the process of optimising the Swedish defence supply system. The first step entails defining principles for distribution and storage.Design/methodology/approachThe research builds on literature reviews, archival records, Swedish military documents, participatory observation at FMV and in the Swedish Armed Forces Head Quarters, study visits to military units, presentations by Subject Matter Experts (SMEs), and war gaming.Principles from business logistics and Supply Chain Management (SCM) were identified and analysed in order to assess their applicability in the Swedish military context. Similarly, military logistics principles from other nations (US and UK), as well as from multinational organisations (UN, NATO, and EU), were identified and analysed. Finally, current and past Swedish logistics principles from guiding documents and military practise were also identified. FindingsThe newly dawned political attention to operational effect, operational capabilities, availability and preparedness must lead to a shift of paradigm in defence logistics. Military logistics must move from the prevailing focus on effectiveness and efficiency in production logistics to an effect based operational logistics, supported by an effective and efficient production logistics. This means that new military logistics principles must be applied. The conducted research has suggested a set of new principles for distribution and storage.The working group has identified and analysed principles in business logistics and SCM, as well as domestic and international principles in military logistics. The working group has found that there is no established set of principles that in and by itself meets the requirements for designing an optimised system for storage and distribution which satisfies the goal and the constraints. The working group has therefore selected principles from different sources and augmented these with a couple of principles constructed by the working group.The working group proposes that the following principles should be established for distribution and storage in the Swedish defence supply chain: Primacy of operational requirements – It is the requirements of the operational commander that must be satisfied. Adapted protection – The requirements for protection must be considered in the selection of system for distribution and storage. Categorisation, segmentation and differentiation – Supplies should be categorised and segmented, and the treatment of segments should be differentiated. Strategic supplies should always be stored in sufficient quantities and volumes in order to ensure initial availability and sustainability until external delivery can be guaranteed. Risk supplies should always be stored in sufficient quantities and volumes in order to ensure initial availability and initial sustainability. Certain leverage supplies may require storage to a certain degree in order not to jeopardise initial availability and initial sustainability. Generally, it is not necessary to store routine supplies. Storage close to military units – Limiting supplies should be stored close to the military units in order to ensure initial availability and initial sustainability for activated and mobilised military units. Storage close to the area of operations – Reserve supplies should be stored close to the envisioned areas of operations in order to ensure operational sustainability. The requirement for redistribution and dispersion in higher levels of preparedness should be minimised. Efficient distribution solutions, which do not restrict operational effect, should be used up until the area of operations. Military units close to the area of operations should have organic distribution capability to be able to handle all requirements for transportation. Postponement – Products should be kept generic as long as possible, and value adding, customising, activities should be postponed as long as possible. Modularisation and bundling of goods and services – Components (goods, services, or combinations of goods and services) should be grouped (bundled) together into larger modules or systems, which at a later stage can be combined in order to create customised end products. Efficient and lean in peace. Effective, agile and responsive in higher levels of preparedness.· Flexibility to adapt the configuration of the supply chain to different levels of threat, preparedness and conflict.Contrary to most supply chains in business logistics, but akin to the reality of supply chains in humanitarian logistics, supply chains in defence logistics must have two distinct different modes: dormant and action. This means moving from applying the principles of efficiency and lean in peace, to the application of the principles of effectiveness, agility and responsiveness in higher levels of preparedness. To have the ability to move between these two modes is an application of the principle of flexibility.The working group has found that several of the principles applied in business logistics are better suited to be components in everyday improvement management within defence logistics, rather than as principles suited for supply chain design and supply chain configuration. Consequently, the working group proposes that improvement management within defence logistics command and control should always address the following issues: Eliminate, reduce and/or redistribute lead-times – Non value adding activities should be eliminated. Time should be allocated so that activities are executed in parallel. It must be ensured that activities are not duplicated between different organisations. Eliminate, reduce and/or adapt to variations and uncertainties – Variations and uncertainties must be identified and analysed, in order to enable elimination or reduction, alternatively allow for required adaptations. Simplify and compress structures and processes – The number of decision elements or nodes in logistics systems, e.g. the number of different variations of products, customers, suppliers, storage nodes, number of steps in distribution channels, levels in product structures, etc. should be reduced. Components, processes, and interfaces should be standardised. Simplify administration and minimise transaction times – Administration should be simplified and the extra lead time due to administrative processer should be minimised.Several of the proposed principles have been validated by SMEs within the Swedish Armed Forces and FMV through war games which have been conducted at the tactical and operational levels for this purpose. However, the working group recommends that further validation activities be conducted, prior to any final implementation and institutionalisation of the proposed principles.Original/valueThe presented work is relevant for any defence organisation contemplating transformation of its logistics system in the light of recent developments with implications for the areas of defence and security policy.
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| 8. |
- Engström, Emelie, et al.
(author)
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A systematic review on regression test selection techniques
- 2010
-
In: Information and Software Technology. - : Elsevier BV. - 0950-5849. ; 52:1, s. 14-30
-
Research review (peer-reviewed)abstract
- Regression testing is verifying that previously functioning software remains after a change. With the goal of finding a basis for further research in a joint industry-academia research project, we conducted a systematic review of empirical evaluations of regression test selection techniques. We identified 27 papers reporting 36 empirical studies, 21 experiments and 15 case studies. In total 28 techniques for regression test selection are evaluated. We present a qualitative analysis of the findings, an overview of techniques for regression test selection and related empirical evidence. No technique was found clearly superior since the results depend on many varying factors. We identified a need for empirical studies where concepts are evaluated rather than small variations in technical implementations.
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| 9. |
- Engström, Emelie, et al.
(author)
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Empirical evaluations of regression test selection techniques: a systematic review
- 2008
-
In: Proceedings of the Second ACM-IEEE international symposium on Empirical Software Engineering and Measurements. - New York, NY, USA : ACM. - 9781595939715 ; , s. 22-31
-
Conference paper (peer-reviewed)abstract
- Regression testing is the verification that previously functioning software remains after a change. In this paper we report on a systematic review of empirical evaluations of regression test selection techniques, published in major software engineering journals and conferences. Out of 2 923 papers analyzed in this systematic review, we identified 28 papers reporting on empirical comparative evaluations of regression test selection techniques. They report on 38 unique studies (23 experiments and 15 case studies), and in total 32 different techniques for regression test selection are evaluated. Our study concludes that no clear picture of the evaluated techniques can be provided based on existing empirical evidence, except for a small group of related techniques. Instead, we identified a need for more and better empirical studies were concepts are evaluated rather than small variations. It is also necessary to carefully consider the context in which studies are undertaken.
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| 10. |
- Faust, Robin, 1992, et al.
(author)
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Role of Surface Morphology on Bed Material Activation during Indirect Gasification of Wood
- 2023
-
In: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 333, Part 1
-
Journal article (peer-reviewed)abstract
- Olivine and alkali-feldspar were utilized in separate campaigns in an indirect dual fluidized bed gasification campaign with woody biomass as fuel. After three days, both bed materials were reported to be active towards tar removal and exhibited oxygen-carrying abilities and had formed an ash layer consisting of an outer ash deposition layer and an inner interaction layer.X-ray microtomography analysis concluded that a preferred deposition of ash happens onto convex regions of the bed particles, which results in an increase in thickness of the ash layer over convex regions. This effect is most pronounced for the outer layer which is a product of ash deposition. The inner layer exhibits a homogeneous thickness and is probably formed by interaction of Ca from the outer layer with the particles. Transmission electron microscopy revealed the presence of Fe and Mn on the surface of the particles in a solid solution with Mg. The oxygen-carrying effect which is found for aged particles is therefore attributed to the presence of Fe and Mn on the surface of aged particles. Alkali were found on the surface of both particles which are likely contributing to the catalytic activity of the material towards tar removal.
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| 11. |
- Ghauch, Hadi, et al.
(author)
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Distributed Low-Overhead Schemes for Multi-stream MIMO Interference Channels
- 2015
-
In: IEEE Transactions on Signal Processing. - : IEEE Signal Processing Society. - 1053-587X .- 1941-0476. ; 63:7, s. 1737-1749
-
Journal article (peer-reviewed)abstract
- Our aim in this work is to propose fully distributed schemes for transmit and receive filter optimization. The novelty of the proposed schemes is that they only require a few forward-backward iterations, thus causing minimal communication overhead. For that purpose, we relax the well-known leakage minimization problem, and then propose two different filter update structures to solve the resulting non-convex problem: though one leads to conventional full-rank filters, the other results in rank-deficient filters, that we exploit to gradually reduce the transmit and receive filter rank, and greatly speed up the convergence. Furthermore, inspired from the decoding of turbo codes, we propose a turbo-like structure to the algorithms, where a separate inner optimization loop is run at each receiver (in addition to the main forward-backward iteration). In that sense, the introduction of this turbo-like structure converts the communication overhead required by conventional methods to computational overhead at each receiver (a cheap resource), allowing us to achieve the desired performance, under a minimal overhead constraint. Finally, we show through comprehensive simulations that both proposed schemes hugely outperform the relevant benchmarks, especially for large system dimensions.
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| 12. |
- Ghauch, Hadi, et al.
(author)
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Distributed precoding and user selection in MIMO interfering networks
- 2015
-
In: 2015 IEEE 6th International Workshop on Computational Advances in Multi-Sensor Adaptive Processing, CAMSAP 2015. - : IEEE conference proceedings. - 9781479919635 ; , s. 461-464
-
Conference paper (peer-reviewed)abstract
- In this work we shed light on the problem of precoding and user selection in MIMO networks. We formulate the problem using the framework of stable matching, whereby a set of users wish to be matched to a set of serving base stations, such as to maximize the sum-rate performance of the system. Though the problem is NP-hard, we propose a suboptimal heuristic that tackles the problem in a distributed fashion: we apply a many-to-one stable matching algorithm to generate a sequence of matchings, and the Weighted MMSE algorithm to perform the precoding. We benchmark our algorithm againt the recently proposed Weighted MMSE with User Assignment algorithm [1].
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| 13. |
- Ghauch, Hadi, 1986-, et al.
(author)
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Interference Alignment via Controlled Perturbations
- 2013
-
In: 2013 IEEE Global Communications Conference (GLOBECOM). - : IEEE. - 9781479913534 ; , s. 3996-4001
-
Conference paper (peer-reviewed)abstract
- In this work, we study the so-called leakage minimization problem, within the context of interference alignment (IA). For that purpose, we propose a novel approach based on controlled perturbations of the leakage function, and show how the latter can be used as a mechanism to control the algorithm's convergence (and thus tradeoff convergence speed for reliability). Although the proposed scheme falls under the broad category of stochastic optimization, we show through simulations that it has a quasi-deterministic convergence that we exploit to improve on the worst case performance of its predecessor, resulting in significantly better sum-rate capacity and average cost function value.
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| 14. |
- Ghauch, Hadi, et al.
(author)
-
Subspace Estimation and Decomposition for Hybrid Analog-Digital Millimetre-Wave MIMO systems
- 2015
-
In: 2015 IEEE 16th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC). - : IEEE. ; , s. 395-399
-
Conference paper (peer-reviewed)abstract
- In this work, we address the problem of channel estimation and precoding / combining for the so-called hybrid millimeter wave (mmWave) MIMO architecture. Our proposed channel estimation scheme exploits channel reciprocity in TDD MIMO systems, by using echoing, thereby allowing us to implement Krylov subspace methods in a fully distributed way. The latter results in estimating the right (resp. left) singular subspace of the channel at the transmitter (resp. receiver). Moreover, we also tackle the problem of subspace decomposition whereby the estimated right (resp. left) singular subspaces are approximated by a cascade of analog and digital precoder (resp. combiner), using an iterative method. Finally we compare our scheme with an equivalent fully digital case and conclude that a relatively similar performance can be achieved, however, with a drastically reduced number of RF chains - 4 ~ 8 times less (i.e., massive savings in cost and power consumption).
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| 15. |
- Ghauch, Hadi, et al.
(author)
-
Subspace Estimation and Decomposition for Large Millimeter-Wave MIMO Systems
- 2016
-
In: IEEE Journal on Selected Topics in Signal Processing. - : Institute of Electrical and Electronics Engineers (IEEE). - 1932-4553 .- 1941-0484. ; 10:3, s. 528-542
-
Journal article (peer-reviewed)abstract
- Channel estimation and precoding in hybrid analog-digital millimeter-wave (mmWave) MIMO systems is a fundamental problem that has yet to be addressed, before any of the promised gains can be harnessed. For that matter, we propose a method (based on the well-known Arnoldi iteration) exploiting channel reciprocity in TDD systems and the sparsity of the channel's eigenmodes, to estimate the right (resp. left) singular subspaces of the channel, at the BS (resp. MS). We first describe the algorithm in the context of conventional MIMO systems, and derive bounds on the estimation error in the presence of distortions at both BS and MS. We later identify obstacles that hinder the application of such an algorithm to the hybrid analog-digital architecture, and address them individually. In view of fulfilling the constraints imposed by the hybrid analog-digital architecture, we further propose an iterative algorithm for subspace decomposition, whereby the above estimated subspaces, are approximated by a cascade of analog and digital precoder/combiner. Finally, we evaluate the performance of our scheme against the perfect CSI, fully digital case (i.e., an equivalent conventional MIMO system), and conclude that similar performance can be achieved, especially at medium-to-high SNR (where the performance gap is less than 5%), however, with a drastically lower number of RF chains (similar to 4 to 8 times less).
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| 16. |
- Ghauch, Hadi, 1986-, et al.
(author)
-
Sum-Rate Maximization in Sub-28-GHz Millimeter-Wave MIMO Interfering Networks
- 2017
-
In: IEEE Journal on Selected Areas in Communications. - : IEEE. - 0733-8716 .- 1558-0008. ; 35:7, s. 1649-1662
-
Journal article (peer-reviewed)abstract
- MIMO systems in the lower part of the millimetre-wave (mmWave) spectrum band (i.e., below 28 GHz) do not exhibit enough directivity and selectively, as compared to their counterparts in higher bands of the spectrum (i.e., above 60 GHz), and thus still suffer from the detrimental effect of interference, on the system sum rate. As such systems exhibit large numbers of antennas and short coherence times for the channel, traditional methods of distributed coordination are ill-suited, and the resulting communication overhead would offset the gains of coordination. In this paper, we propose algorithms for tackling the sum-rate maximization problem that are designed to address the above-mentioned limitations. We derive a lower bound on the sum rate, a so-called difference of log and trace (DLT) bound, shed light on its tightness, and highlight its decoupled nature at both the transmitters and receivers. Moreover, we derive the solution to each of the subproblems that we dub non-homogeneous waterfilling (a variation on the MIMO waterfilling solution), and underline an inherent desirable feature: its ability to turn-OFF streams exhibiting low SINR, and contribute to greatly speeding up the convergence of the proposed algorithm. We then show the convergence of the resulting algorithm, max-DLT, to a stationary point of the DLT bound. Finally, we rely on extensive simulations of various network configurations, to establish the fast-converging nature of our proposed schemes, and thus their suitability for addressing the short coherence interval, as well as the increased system dimensions, arising when managing interference in lower bands of the mmWave spectrum. Moreover, our results suggest that interference management still brings about significant performance gains, especially in dense deployments.
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| 17. |
- Gustafsson, Thomas, et al.
(author)
-
Automotive System Testing by Independent Guarded Assertions
- 2015. - 10
-
In: 2015 IEEE Eighth International Conference on Software Testing, Verification and Validation Workshops (ICSTW). - 9781479918850
-
Conference paper (peer-reviewed)abstract
- Testing is a key activity in industry to verify and validate products before they reach end customers. In hardwarein- the-loop system-level verification of automotive systems, testing is often performed using sequential execution of test scripts, each containing a mix of stimuli and assertions. In this paper, we propose and study an alternative approach for automated system-level testing automotive systems. In our approach, assertion-only test scripts and one (or several) stimulionly script(s), execute concurrently on the test driver. By separating the stimuli from the assertions, with each assertion independently determining when the system under test shall be verified, we seek to achieve three things: 1) tests that better represent real-world handling of the product, 2) reduced test execution time, and 3) increased defect detection. In addition to describing our proposed approach in detail, we provide experimental results from an industrial case study evaluating the approach in an automotive system test environment.
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| 18. |
- Kim, Thanh Tung, et al.
(author)
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Combining long-term and low-rate short-term channel state information over correlated MIMO channels
- 2008
-
In: IEEE Transactions on Wireless Communications. - : IEEE Communications Society. - 1536-1276 .- 1558-2248. ; 7:7, s. 2409-2414
-
Journal article (peer-reviewed)abstract
- A simple structure to exploit both long-term and partial short-term channel state information at the transmitter (CSIT) over a family of correlated multiple-antenna channels is proposed. Partial short-term CSIT in the form of a weighting matrix is combined with a unitary transformation based on the long-term channel statistics. The heavily quantized feedback link is directly optimized to maximize the expected achievable rate under different power constraints, using vector quantization and convex optimization techniques on a sample channel distribution. Robustness against errors in the feedback link is also pursued with tools in channel optimized vector quantization. Simulations indicate the benefits of the proposed scheme.
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| 19. |
- Kim, Thanh Tung, et al.
(author)
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Combining short-term and long-term channel state information over correlated MIMO channels
- 2006
-
In: 2006 IEEE International Conference on Acoustics, Speech, and Signal Processing. - 142440469X ; , s. 13-16
-
Conference paper (peer-reviewed)abstract
- A simple structure to exploit both long-term and partial short-term channel state information at the transmitter (CSIT) over a family of correlated multiple-antenna channels is proposed. Partial short-term CSIT in the form of a weighting matrix is obtained via a resolution-constrained feedback link, combined with a unitary transformation based on the long-term channel statistics. The feedback link is optimized to maximize the expected achievable rate under different power constraints, using vector quantization techniques. Simulations indicate the benefits of the proposed scheme in all scenarios considered.
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| 20. |
- Kim, Thanh Tung, et al.
(author)
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Quantized feedback design for MIMO broadcast channels
- 2007
-
In: 2007 IEEE International Conference on Acoustics, Speech, and Signal Processing. ; , s. 1-4
-
Conference paper (peer-reviewed)abstract
- Low-rate feedback design for multiple-input multiple-output broadcast channels is studied under a vector quantization framework. Iterative algorithms are proposed to design the partial feedback link, the scheduler, and the linear precoding code-book. It is demonstrated that the gain due to multi-user diversity can be significant even with heavily quantized channel state information at the transmitter. Our results highlight the potential of multi-user diversity, even with simple schemes and extremely-low-rate feedback.
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| 21. |
- Leijon, Mats, et al.
(author)
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On the Physics and Economics of Renewable Electric Energy Sources : part I Utilization
- 2008
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In: PROCEEDINGS OF THE 8TH WSEAS INTERNATIONAL CONFERENCE ON ELECTRIC POWER SYSTEMS, HIGH VOLTAGES, ELECTRIC MACHINES. - : WORLD SCIENTIFIC AND ENGINEERING ACAD AND SOC. - 9789604740260 ; , s. 227-232
-
Conference paper (peer-reviewed)abstract
- Increasingly, environmental concerns have led to the installation of Renewable Energy Technologies (RETs) despite the fact that they are recognized as expensive. Innovative efforts within the area are beset by difficulties [1] Grubb 1994, where improvements in cost effectiveness of total energy conversion systems are often insignificant and misdirected. We have investigated how RETs can be evaluated, in terms of economy and engineering solutions, by studying the fundamental physics of renewable energy sources and how it matches with the RETs. This match is described by the "Degree of Utilization". The findings indicate that new innovations should focus on possible full loading hours, since RETs that are correctly matched to their energy source generate a higher amount of electric energy and become more competitive. In cases where this aspect has been ignored, leading to relatively small degrees of utilization, it can be understood as an engineering mismatch between installed power, converted energy, and the fundamental physics of the renewable energy sources. Since there is a strong and possibly biased support for so-called mature RETs and already existing solutions, a clarification of how fundamental physical laws affect the cost of investment and payback of investment is needed. The present paper is part I out of 11 and if focuses on the difference between power and energy and the physics of different energy sources and their utilization.
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| 22. |
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| 23. |
- Leijon, Mats, et al.
(author)
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On the physics of power, energy and economics of renewable electric energy sources - Part I
- 2010
-
In: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 35:8, s. 1729-1734
-
Journal article (peer-reviewed)abstract
- Environmental concerns have increasingly led to the installation of Renewable Energy Technologies (RETs) despite the fact that they are recognized as expensive. Innovative efforts within the area are beset with difficulties [1], and they are at risk of producing misdirected or insignificant improvements in terms of the cost effectiveness of total energy conversion systems. This paper investigates how RETs can be evaluated, in terms of economy and engineering solutions, by studying the fundamental physics of renewable energy sources and how it matches with the RETs. This match is described by the "Degree of Utilization". The findings indicate that new innovations should focus on the possible number of full loading hours. RETs that are correctly matched to their energy source generate a higher amount of electric energy and have a higher potential of becoming more competitive. In cases where this aspect has been ignored, leading to relatively small degrees of utilization, it can be understood as an engineering mismatch between installed power, converted energy, and the fundamental physics of the renewable energy sources. Since there is a strong and possibly biased support for so-called mature RETs and already existing solutions, a clarification of how fundamental physical laws affect the cost of investments and payback of investments is needed. The present paper is part I out of II and it focuses on the difference between power and energy and the physics of different energy sources and their utilization. (C) 2009 Elsevier Ltd. All rights reserved.
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| 24. |
- Michaëlsson, Isak, et al.
(author)
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Circulating Brain Injury Biomarkers: A Novel Method for Quantification of the Impact on the Brain After Tumor Surgery.
- 2023
-
In: Neurosurgery. - 0148-396X .- 1524-4040. ; 93:4, s. 847-856
-
Journal article (peer-reviewed)abstract
- Clinical methods to quantify brain injury related to neurosurgery are scarce. Circulating brain injury biomarkers have recently gained increased interest as new ultrasensitive measurement techniques have enabled quantification of brain injury through blood sampling.To establish the time profile of the increase in the circulating brain injury biomarkers glial fibrillary acidic protein (GFAP), tau, and neurofilament light (NfL) after glioma surgery and to explore possible relationships between these biomarkers and outcome regarding volume of ischemic injury identified with postoperative MRI and new neurological deficits.In this prospective study, 34 adult patients scheduled for glioma surgery were included. Plasma concentrations of brain injury biomarkers were measured the day before surgery, immediately after surgery, and on postoperative days 1, 3, 5, and 10.Circulating brain injury biomarkers displayed a postoperative increase in the levels of GFAP ( P < .001), tau ( P < .001), and NfL ( P < .001) on Day 1 and a later, even higher, peak of NFL at Day 10 ( P = .028). We found a correlation between the increased levels of GFAP, tau, and NfL on Day 1 after surgery and the volume of ischemic brain tissue on postoperative MRI. Patients with new neurological deficits after surgery had higher levels of GFAP and NfL on Day 1 compared with those without new neurological deficits.Measuring circulating brain injury biomarkers could be a useful method for quantification of the impact on the brain after tumor surgery or neurosurgery in general.
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| 25. |
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| 26. |
- Runeson, Per, et al.
(author)
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Reference-based search strategies in systematic reviews
- 2009
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In: [Host publication title missing].
-
Conference paper (peer-reviewed)abstract
- In systematic reviews, the number of articles found by search strings tend to be very large. In order to limit the number of articles to handle manually, we investigate a search strategy based on references between papers. We first identify a “take-off paper” which is the starting point for the search and then we follow the references from that paper. We also investigate “cardinal papers”, i.e. papers that are referenced by many authors, and let the references to those papers guide the selection in the systematic review. We evaluate the search strategies on three published systematic reviews. The results vary greatly between the three studied systematic reviews, from 88% reduction to 92% extension of the original paper set.
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| 27. |
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| 28. |
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| 29. |
- Skoglund, Annika, 1977-, et al.
(author)
-
Juvenocracy : Juvenocratic Spaces
- 2020
-
In: The SAGE Encyclopedia of Children and Childhood Studies. - London and New York : Sage. - 9781473942929
-
Book chapter (peer-reviewed)abstract
- Juvenocracy—i.e., when children and youth govern adults—has been academically developed and extended as a concept since the early 1970s. Since that time, scholarly thought has moved away from static modernistic attributions of power to focus more on how power relations are negotiated and unfold. Whilst early conceptualizations of juvenocracy rest on assumptions about existing structures, later theorizing rests on an affirmation of contingency. With this shift, studies of juvenocracy have come to address broader aspects of child and youth authority in adolescence processes and intergenerational relations, also conceptualized as ‘juvenocratic spaces’. Early approaches to juvenocracy share an interest in how individuals can be transformed by a group and how an individual’s identity is compromised in favour of a collective identity. In these studies, juvenocracy has mainly been used to shed light on negative exercises of power and its corrosive, long and short term, effects. The overall purpose has been to grapple with problematic groups and activities identified in social contexts and specific geographical locations where people in general have been found to suffer from illicit activities and underprivileged conditions. In these contexts, juvenocracy draws attention to how masculine spaces unfold via a violence and dominance that differs from the norm of socialization in other groups. For instance, research by Zuckerman and Merton in 1972 described how juvenocracy was formed by generational shifts of rule in groups, or what they called ‘gangs’, dominated by males. When symbolic fathers and uncles were replaced by sons, the juvenocracy took shape. By turning to identity theory, they suggested that the sons opposed the older generations to form a new and more updated masculine identity and younger gang, to carve out new rules of its own. The analytical aim in studies of identity processes has concentrated on exposing problematic socialization and dysfunctional group dynamics. By applying common cultural categories, scholars have investigated the specifics of a shared culture or subculture, whereby juvenocracy has been attached to male groups with criminal inclinations typically also identified as black, Hispanic or Latino. In these cases, popular culture has been pointed out as playing a significant role, concluding that juvenocracy is supported by music and lyrics that praise masculine domination techniques, which in turn enforces and enriches the group-specific rules. In conjunction with an academic tendency to apply presumed cultural markers to explain power relations in groups deemed to suffer from negative juvenocratic practices, juvenocracy became gendered and delimited to explanations of youth patriarchies. In contrast, juvenocracy has in a few instances been used to describe a loose organisation of youth who are under 25 years, without focus on a specific ethnic cultural context or gender. In these cases juvenocracy is tightly linked to adolescence processes, with an academic interest in how old norms, and often the parents, are questioned by resistance and voicing. Studies of teenagers who engage politically and build collectives around music, protests and specific values, is one example of how an interest in juvenocracy merge with an interest in teenage liberation within child and youth studies. Similar interests in liberation have been studied by looking back in time, exposing how children historically have been processed differently into adolescence. For example when they were dressed up as adults in the 16:th century, in rites of passage at children’s ‘age of reason’ (at about 7 years old), or with the ‘emancipation of minors’, no longer under adult supervision (at about 18 years old). The main interest in studies of juvenocracy is how this boundary between childhood and adulthood is negotiated differently at different times and in various contexts. Studies of juvenocracy often seek to explain the basis for these negotiations by tracing contemporary manifestations of Jean-Jacques Rousseau’s romantic portraits of children, or Immanual Kant’s cosmopolitan ideas about pedagogy. Historically, pedagogic approaches often targeted the ‘unknowing’ and ‘uncivilized child’, i.e., not yet fully considered a full subject with human capabilities, who was to be transformed to reach maturity. With increasing demands to see children as equals they have been understood differently and inscribed with increased authority by observers and in social institutions. Social norms have merged with theories about children’s intellectual development, observable in the turn to pedagogical neuroscience. Juvenocracy, consequently, is no longer studied to mainly address problematic social contexts in wishes for remedy, but have been studied in contexts where the child is made more competent, knowledgeable, agentic and reasonable, than adults. The idea of a prosperous and healthy juvenocracy has thrived on specific arenas of intergenerational relations, mainly in the home and at school, where the prospective authority of youth is put in immediate and constant tension with the present deteriorating authority of adults and elderly people. A growing interest in children’s authority is also reflected in research about internet skills and gadget compatibility. Juvenocracy can be understood as an unfolding process through shifts in language and conceptualisation—for instance, noting where the child or young person resides along different power continua such as: mature – immature; rational – irrational; experienced – inexperienced, which map onto adult-child authority relations. These dichotomies suggest that juvenocracy develops when basic assumptions and norms, visible in these category pairs, somehow are disrupted. That is, adults are normally conceived to be more mature, rational and experienced than children and youth, but where a disruption of these qualities among adults commonly occurs in two ways. First, category pairs can be inversed, by which the child becomes more mature, rational or experienced than the adult. Second, some other category pairs, in favour of children’s capacities, may be introduced and emphasized to devalue adult competences, such as: playful - subdued; imaginative – unimaginative; innocent – tainted. In the wake of political quests to secure children’s rights and enforce deliberative democratic agendas in advanced liberal economies, children’s predetermined qualities have been increasingly negotiated, disrupted and mobilized. The discipline of pedagogy has consequently turned to the ideological construct of ‘the competent child’ by unlocking children’s vulnerability in attempts to nurture them into more capable states. After victimizing children and youth by pointing to their precarious position in society, efforts have been made to activate them through their own ambitions for power. They have for example been invited to set up democratic elections in school, or youth governments and international assemblies with a ruling child president - to play politics. The capacity to play is in this case targeted to foster children into citizens who voluntarily affirm adult-like responsibilities. Whereby juvenocracy is studied as a productive process to better understand how children and youth are trained to affirm and handle authority and increased influence, perhaps even as activists. The Swedish teenage girl Greta Thunberg, nominated for the Nobel peace prize due to her school strike with calls for more effective acts on climate change, is a case in point. She has skipped mandatory school days to engage in politics since adult politicians have proven their incompetence to accomplish real transformations. Attempts to mitigate how children are constructed into victims can be clearly observed in discourses about sustainability and future catastrophes. In this instance, children are suggested to be more vulnerable to climate shifts and migratory patterns, in comparison to adults. At the same time, children are conceived to be more close to nature, resilient and adaptable than adults. And particularly in cases where the future is at stake, children are commonly constructed as the rightful stakeholders, since they are taken to be the future. Key in the making of children and youth into an authority is in this case a shift in the category pair ‘rational-irrational’, due to a strengthening of the pair ‘tainted-innocent’. Children and youth are on the outset defined as innocent, without blame for today’s problems, and without vested interest in ideas for a better future. This makes children and youth into more rational humans who are better equipped to speak for humankind, in comparison to adults, who in effect become tainted and irrational. At the same time, they remain closer to the animal kingdom, as not yet fully civilized. Knowledge dissemination about sustainability is therefore a prime example of how adolescence processes are regulated and intergenerational relations can be continuously negotiated. And it has been argued that pedagogic expertise and expertise on sustainability productively merge and is mobilized through juvenocratic spaces, where especially Northern European children and youth are encouraged to foster sustainable consumption and ways of living worldwide. Depending on age category, the arena for influence extends from small children who are playing sustainability board games with parents at home, to older children who are instructing teachers about sustainability at school, to youth who travel around the world as part of some global NGO program to spread sustainability thinking to ‘non-sustainable’ parts of the world. This shows how pedagogy has merged with efforts to stimulate participative democracy to make children into knowledge producers and distribution channels with global outreach. It is a moveme
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| 30. |
- Skoglund, Annika, 1977-, et al.
(author)
-
”Juvenocracy” – the politicization of children in climate change
- 2011
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In: Politics and Popular Culture 4.
-
Conference paper (peer-reviewed)abstract
- In April 2008, a possibility to ‘save the world at home’ was presented at the back of milk cartoons produced by Arla, purchased across Sweden. Coupled with various stories and tips on how to change the everyday practices of the family, this ambitious objective called upon children to look after their parents in climate change. ‘See through that your parents check the air pressure in the tires of the car’, exemplifies one of the typical statements that turn the relation between breeder and bred around. In this paper we present how children are empowered to exercise their potential power through technologies of responsibilization and various Internet-related technical solutions enhancing self-reflexivity and connectivity by fostering calculative capabilities. We also trace how these power relations have evolved from personnel management and the prohibition of child labour in factories during the 19th and 20th century, to the 1970s Swedish family legislation portraying children as ‘equal individuals’, ending in an ecological system’s networked society. The analysis illustrates how children are politicized in climate change to produce a ‘juvenocratic’ governmental rationality. This governmental rationality is increasingly operationalized through climate change risk politics, but can also be observed in more general biopolitics, as when pre-schoolers are brought to homes for elderly people to sing traditional songs and have common fruit pauses to ‘make the elderly eat more and healthier’ (June, 21st , 2011). While adults are incapacitated to work upon their self without children or the child within themselves, children are predicted to have the ability to foster everyday activities. This discourse produces the child as an authority and relay of expertise with capacity to stabilize the consumption of adults, by providing ethical guidelines intragenerationally, disseminated through what we conceptualize as ‘juvenocracy’.
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| 31. |
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| 32. |
- Skoglund, Annika, et al.
(author)
-
On the Physics and Economics of Renewable Electric Energy Sources : part II Engineering
- 2008
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In: PROCEEDINGS OF THE 8TH WSEAS INTERNATIONAL CONFERENCE ON ELECTRIC POWER SYSTEMS, HIGH VOLTAGES, ELECTRIC MACHINES. - 9789604740260 ; , s. 233-238
-
Conference paper (peer-reviewed)abstract
- Renewable Energy Technologies (RETs) are often recognized as expensive to install and maintain. Therefore they are also seen as less competitive relative traditional types of electric energy conversion systems. Even so, political and environmental concerns have lately led to increased installation of various RETs, especially wind power. To facilitate a faster diffusion of new innovations and installations of RETs in general, we argue that focus should be on the possible number of full loading hours since it strongly affects the economical output. This paper elaborates on this problem by exemplifying the interface between physics, engineering and economy for different RET plants, while others commonly attack it from the direction of policies and regulative frameworks [1] Grubb 1990, [2] Harmelink et al 2006 [3] Kaldellis et al. 2005, [4] Komor & Bazillan 2005, [5] Palmer & Burtraw 2005, [6] Panoutsou 2008. In part I of this article [7] Leijon et al define the "Degree of Utilization" and show why the amount of full loading hours are important for the renewable generation of electric energy. As part 1.1, this article elaborates further on the Degree of Utilizatoin and shows why it is crucial for the economical optimization of a specific RET system. The results show how the choice of renewable energy source and a correctly matched RET design affects the economy of a RET plant.
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| 33. |
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| 34. |
- Skoglund, Annika, et al.
(author)
-
On the physics of power, energy and economics of renewable electric energy sources - Part II
- 2010
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In: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 35:8, s. 1735-1740
-
Journal article (peer-reviewed)abstract
- Renewable Energy Technologies (RETs) are often recognized as less competitive than traditional electric energy conversion systems. Obstacles with renewable electric energy conversion systems are often referred to the intermittency of the energy sources [1] and the relatively high maintenance cost. However, due to an intensified discourse on climate change and its effects, it has from a societal point of view, become more desirable to adopt and install CO2 neutral power plants. Even if this has increased the competitiveness of RETs in a political sense, the new goals for RET installations must also be met with economical viability. We propose that the direction of technical development, as well as the chosen technology in new installations, should not primarily be determined by policies, but by the basic physical properties of the energy source and the associated potential for inexpensive energy production. This potential is the basic entity that drives the payback of the investment of a specific RET power plant. With regard to this, we argue that the total electric energy conversion system must be considered if effective power production is to be achieved, with focus on the possible number of full loading hours and the Degree of Utilization [2]. This will increase the cost efficiency and economical competitiveness of RET investments, and could enhance faster diffusion of new innovations and installations without over-optimistic subsidies. This paper elaborates on the overall problem of the economy of renewable electric energy conversion systems by studying the interface between physics, engineering and economy reported for RET power plants in different scientific publications. The core objective is to show the practical use of the Degree of Utilization and how the concept is crucial for the design and economical optimization disregarding subsidies. The results clearly indicate that the future political regulative frameworks should consider the choice of renewable energy source since this strongly affects the economical output from the RET power plants. (C) 2009 Elsevier Ltd. All rights reserved.
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| 35. |
- Skoglund, Mats, et al.
(author)
-
A case study of the class firewall regression test selection technique on a large scale distributed software system
- 2005
-
In: 2005 International Symposium on Empirical Software Engineering (ISESE), Proceedings. - NEW YORK : IEEE. - 9780780395084 - 0780395077 ; , s. 74-83
-
Conference paper (peer-reviewed)abstract
- Regression testing is expensive and may consume much of organizations' software development budgets. Thus, it is of interest to reduce the total time devoted to test execution by using test selection techniques. Many techniques have been proposed but few have been evaluated on real-world, large scale systems. In this paper we report on an empirical evaluation of using the class firewall regression test selection technique, in combination with scenario testing, on a large scale industrial software system using the Java byte code in the analysis. The study was performed on a large complex distributed software system in one of Sweden's largest banks. Effects of using scenario testing together with regression test selection are reported. The results are that not all test cases were selected by the class firewall selection technique. Using scenario testing, where test cases are dependent,. affects the number of test cases selected, as do the location and number of changes in the system.
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| 36. |
- Skoglund, Mats, et al.
(author)
-
A Case Study of The Class Firewall Regression Test Selection Technique using Scenario Testing on a Large Scale Distributed Software System
- 2005
-
In: Empirical software engineering, 2005. - Piscataway, N.J : IEEE conference proceedings. - 0780395077 ; , s. 74-83
-
Book chapter (peer-reviewed)abstract
- Regression testing is expensive and may consume much of organizations’ software development budgets. Thus, it is of interest to reduce the total time devoted to test execution by using test selection techniques. Many techniques have been proposed but few have been evaluated on real-world, large scale systems. In this paper we report on an empirical evaluation of using the class firewall regression test selection technique, in combination with scenario testing, on a large scale industrial software system using the Java byte code in the analysis. The study was performed on a large complex distributedsoftware system in one of Sweden’s largest banks. Effects of using scenario testing together with regression test selection are reported. The results are that not all test cases were selected by the class firewall selection technique. Using scenario testing, where test cases are dependent, affects the number of test cases selected, as do the location and number of changes in the system.
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| 37. |
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| 38. |
- Skoglund, Mats, et al.
(author)
-
Alias control with read-only references
- 2002
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In: PROCEEDINGS OF THE 6TH JOINT CONFERENCE ON INFORMATION SCIENCES. - DURHAM : ASSOC INTELLIGENT MACHINERY. ; , s. 387-391
-
Conference paper (peer-reviewed)abstract
- In object-oriented programs, the possibility of having an alias to an object's mutable state is a known source of bugs making programs difficult to test and maintain. We propose an access mode system for limiting the effects of aliasing by associating, with each reference, an access right to the object to which the reference refer. Mutator methods may not be invoked on read references, and only read references to the state can be obtained via any method invoked on a read reference. This enables exporting read references to objects without risking the objects being modified. The system realises access modes by annotations on variables, methods, method returns and parameters to methods. It is completely statically checkable without any need for run-time representation of modes and does not impose any run-time overhead.
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| 39. |
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| 40. |
- Skoglund, Mats, 1971-
(author)
-
Curbing Dependencies in Software Evolution of Object-Oriented Systems
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- Relationships between classes and objects in object-oriented software are necessary in order for the parts of the systems to provide dynamic behavior. These inherent relationships also create dependencies which can give rise to problems for software evolution of object-oriented software systems. Dependencies in software make systems difficult to understand, reuse, change and verify.This thesis presents analytical and empirical investigations of dependency-related problems in software evolution of object-oriented software and on how such problems can be handled with dependency focused techniques, methods and processes.The research presented in this thesis includes: Development of a programming language construct for controlling dependencies; formal experiments on code inspection techniques; exploring change strategies' effects on test suites; an industrial case study of regression test selection techniques for object-oriented software; proving the efficiency and defect detection capabilities of a novel regression test selection technique.The thesis contributes to increased knowledge on the role of dependencies in software evolution of object-oriented software. Specific contributions are a programming language construct that can control access to dependencies in software. Other main contributions are insights on the efficiency of dependency focused code inspection techniques and contribution to the knowledge on dependency-based regression test selection techniques for large scale software. Another contribution is a novel change-based regression test selection technique.
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| 41. |
- Skoglund, Martin, et al.
(author)
-
Enhancing Safety Assessment of Automated Driving Systems with Key Enabling Technology Assessment Templates
- 2023
-
In: Vehicles. - 2624-8921. ; 5:4, s. 1818-1843
-
Journal article (peer-reviewed)abstract
- The emergence of Automated Driving Systems (ADSs) has transformed the landscape of safety assessment. ADSs, capable of controlling a vehicle without human intervention, represent a significant shift from traditional driver-centric approaches to vehicle safety. While traditional safety assessments rely on the assumption of a human driver in control, ADSs require a different approach that acknowledges the machine as the primary driver. Before market introduction, it is necessary to confirm the vehicle safety claimed by the manufacturer. The complexity of the systems necessitates a new comprehensive safety assessment that examines and validates the hazard identification and safety-by-design concepts and ensures that the ADS meets the relevant safety requirements throughout the vehicle lifecycle. The presented work aims to enhance the effectiveness of the assessment performed by a homologation service provider by using assessment templates based on refined requirement attributes that link to the operational design domain (ODD) and the use of Key Enabling Technologies (KETs), such as communication, positioning, and cybersecurity, in the implementation of ADSs. The refined requirement attributes can serve as safety-performance indicators to assist the evaluation of the design soundness of the ODD. The contributions of this paper are: (1) outlining a method for deriving assessment templates for use in future ADS assessments; (2) demonstrating the method by analysing three KETs with respect to such assessment templates; and (3) demonstrating the use of assessment templates on a use case, an unmanned (remotely assisted) truck in a limited ODD. By employing assessment templates tailored to the technology reliance of the identified use case, the evaluation process gained clarity through assessable attributes, assessment criteria, and functional scenarios linked to the ODD and KETs.
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| 42. |
- Skoglund, Mats, et al.
(author)
-
Improving class firewall regression test selection by removing the class firewall
- 2007
-
In: International journal of software engineering and knowledge engineering. - 0218-1940. ; 17:3, s. 359-378
-
Journal article (peer-reviewed)abstract
- One regression test selection technique proposed for object-oriented programs is the Class firewall regression test selection technique. The selection technique selects test classes for regression test, which test changed classes and classes depending on changed classes. However, in empirical studies of the application of the technique, we observed that another technique found the same defects, selected fewer tests and required a simpler, less costly, analysis. The technique, which we refer to as the Change-based regression test selection technique, is basically the Class firewall technique, but with the class firewall removed. In this paper we formulate a hypothesis stating that these empirical observations are not incidental, but an inherent property of the Class firewall technique. We prove that the hypothesis holds for Java in a stable testing environment, and conclude that the effectiveness of the Class firewall regression testing technique can be improved without sacrificing the defect detection capability of the technique, by removing the class firewall.
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| 43. |
- Skoglund, Mats, et al.
(author)
-
Improving Class Firewall Regression Testing by Removing the Class Firewall
- 2007
-
In: International journal of software engineering and knowledge engineering. - : World Scientific Publishing Co.. - 0218-1940. ; 17:3, s. 359-378
-
Journal article (peer-reviewed)abstract
- One regression test selection technique proposed for object-oriented programs is the Class firewall regression test selection technique. The selection technique selects test cases for regression test, which test changed classes and classes depending on changed classes. However, in empirical studies of the application of the technique, we observed that another technique found the same defects, selected fewer tests and required a simpler, less costly, analysis. The technique, which we refer to as the Change-based regression test selection technique, is basically the Class firewall technique, but with the class firewall removed. In this paper we formulate a hypothesis stating that these empirical observations are not incidental, but an inherent property of the Class firewall technique. We prove that the hypothesis holds for Java in a stable testing environment, and conclude that the effectiveness of the Class firewall regression testing technique can be improved without sacrificing the defect detection capability of the technique, by removing the class firewall.
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| 44. |
- Skoglund, Mats
(author)
-
Practical use of encapsulation in object-oriented programming
- 2003
-
In: SERP'03. - ATHENS : C S R E A PRESS. ; , s. 554-560
-
Conference paper (peer-reviewed)abstract
- Even though an OO program may have a high degree of encapsulation it is still sometimes possible to modify the inner representation of compound objects. In for example Java there is little to prevent references exported from a compound object to be used by its receivers. Thus it may be possible to change the states of inner objects of a compound object from the outside leading to invariants may be broken. This is often referred to as the representation exposure problem and many solutions to this problem have been proposed. There is, however, a lack of empirical evidence that this is actually a practical problem in the software industry. In this paper we report our findings from interviews conducted among software engineers on their view on encapsulation and information hiding issues, representation exposure, their we of OO programming languages, their way of working and their opinions on tools and techniques supporting encapsulation, information hiding and representation exposure.
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| 45. |
- Skoglund, Mats
(author)
-
Sharing Objects by Read-only References
- 2002
-
In: Algebraic methodology and software technology. - Berlin : Springer Berlin/Heidelberg. - 3540441441 ; , s. 457-472
-
Book chapter (peer-reviewed)abstract
- Exporting objects by reference can be problematic since thereceivers can use the received reference to perform state changing operationson the referenced object. This can lead to errors if the referencedobject is a subobject of a compound object not anticipating the change.We propose an extension of a type system with a read-only constructthat can be used to control access to state changing methods. We formulateand prove a read-only theorem for read-only references stating thata read-only reference cannot be used to perform operations that changeits referenced object state.
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| 46. |
- Skoglund, Mats
(author)
-
Survey of the Usage of Encapsulation in Object-Oriented Programming
- 2003
-
In: Proceedings of the International Conference on Software Engineering Research and Practice, SERP '03, June 23 - 26, 2003, Las Vegas, Nevada, USA, Volume 2.
-
Conference paper (peer-reviewed)abstract
- In object-oriented programming the concept of encapsulation is used to create abstract datatypes that should be possible to modify only through their external interface. One way to enforce this kind of encapsulation is to declare variables with different access modifiers, such as private or public. However, when using private variables in programming languages with reference semantics, such as e.g. Java, it is only the names of the variables that are protected, not the real objects pointed to by the variables. This problem is sometimes referred to as the representation exposure problem and many proposals addressing this problem have been presented. There is, however, a lack of empirical data on how widespread this problem is in the software industry and its effect on software quality. In this paper we report our finding from a questionnaire survey conducted among software engineers on their view on encapsulation and information hiding issues, their use of OO programming languages, their way of working and their opinions on tools and techniques supporting encapsulation, information hiding and representation exposure
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| 47. |
- Sobiech, Cilli, et al.
(author)
-
Safety Case for Autonomous Trucks (SCAT)
- 2023
-
Reports (other academic/artistic)abstract
- To aim for market introduction and sustainability of automated vehicles requires technology innovation towards safe products and policy innovation to enable testing on open roads and type approvals. Further, it needs an enabling infrastructure to provide reliable connectivity, business models and increased public acceptance of this new technology. The project SCAT – Safety Case for Autonomous Trucks contributed to this transmission by looking at new policy strategies and system tests to prove how to handle vehicles when introducing this new technology safely. Main objective of the project was to investigate more systematically – from a legal and technical perspective – how to safely operate remote controlled vehicles in mixed traffic and with higher velocity. A safety case for the selected traffic environment has been described and explorative tests have been performed at the AstaZero test site in Sweden. This allowed us to investigate limiting parameters and stress testing the system's boundaries under real conditions with higher velocity – before the actual demo will be run. With regards to policy, we addressed which obligations drivers and road users have according to today's regulations and which of those may need to be handled through technological development, but also through adaptation of legislation in terms of new roles, tasks, and liability when a vehicle is driven automatically. We looked also at if and how these issues are treated in national and international legislation, in Sweden, France and the USA. What we learned from exploring the safety case contributes to practical improvement, theory building and recommendations on how to safely operate the vehicles. Together the partners have developed an approach to advanced argumentation for safety. In our approach, we combined policy lab methodology and an investigation of the technical safety aspects that helped to identify gaps and tests for improved safety. The approach provides step-by-step guidance before future trials. The project was running from October 2020 until September 2022. The consortium consisted of the partners AstaZero, Einride, Ericsson, RISE (coordinator), Telia as well as reference partners in France and the USA.
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| 48. |
- Tolli, Antti, et al.
(author)
-
Distributed Coordinated Transmission with Forward-Backward Training for 5G Radio Access
- 2019
-
In: IEEE Communications Magazine. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0163-6804 .- 1558-1896. ; 57:1, s. 58-64
-
Journal article (peer-reviewed)abstract
- CoMP transmission and reception have been considered in cellular networks for enabling larger coverage, improved rates, and interference mitigation. To harness the gains of coordinated beamforming, fast information exchange over a backhaul connecting the cooperating BSs is required. In practice, the bandwidth and delay limitations of the backhaul may not be able to meet such stringent demands. These impairments motivate the study of cooperative approaches based only on local CSI that require minimal or no information exchange between the BSs. To this end, several distributed approaches are introduced for CB-CoMP. The proposed methods rely on the channel reciprocity and iterative spatially precoded over-the-air pilot signaling. We elaborate how F-B training facilitates distributed CB by allowing BSs and UEs to iteratively optimize their respective transmitters/receivers based on only locally measured CSI. The trade-off due to the overhead from the F-B iterations is discussed. We also consider the challenge of dynamic TDD where the UE-UE channel knowledge cannot be acquired at the BSs by exploiting channel reciprocity. Finally, standardization activities and practical requirements for enabling the proposed F-B training schemes in 5G radio access are discussed.
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