| 1. |
- Cvitic, Petya Hristova, et al.
(författare)
-
Investigating Software Testing and Maintenance of Open-Source Distributed Ledger
- 2023
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Ingår i: Proceedings - 2023 IEEE International Conference on Software Analysis, Evolution and Reengineering, SANER 2023. - : IEEE conference proceedings. - 9781665452786 ; , s. 886-896
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Konferensbidrag (refereegranskat)abstract
- A distributed ledger is the backbone of all blockchain solutions. It provides a shared database spreading across a network of nodes. The number of DL solutions and their implementations has grown in recent years. Besides the architectural and performance promises of these solutions, organizations seekingto implement DL also need to consider the overall quality of the software available and its ecosystem. Particularly, previous research has identified the need to better understand the testing and maintenance practices behind these types of technologies. This paper investigates the testing and maintenance of 18 different open-source projects that implement distributed ledgers. We perform a manual inspection of test artefacts and mine the history of commits, issues and contributors of the chosen projects to understand the landscape of testing and maintenance in these projects. Our findings suggest that unit and integration tests are present in most projects, they do not follow a holistic system testing approach. Moreover, projects rely on a small team of core contributors (5 on average). While the projects are continuously maintained, larger changes are uncommon. Our results can be used for benchmarking and pinpointing areas of improvement for the development of distributed ledgers.
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| 2. |
- Cvitic, Petya Hristova, et al.
(författare)
-
Investigating Software Testing and Maintenance of Open-Source Distributed Ledger
- 2023
-
Ingår i: Proceedings - 2023 IEEE International Conference on Software Analysis, Evolution and Reengineering, SANER 2023. - : IEEE. - 2833-9061. - 9781665452786
-
Konferensbidrag (refereegranskat)abstract
- A distributed ledger is the backbone of all blockchain solutions. It provides a shared database spreading across a network of nodes. The number of DL solutions and their implementations has grown in recent years. Besides the architectural and performance promises of thesesolutions, organizations seekingto implement DL also need to consider the overall quality of the software available and its ecosystem. Particularly, previous research has identified the need to better understand the testing and maintenance practices behind these types of technologies. This paper investigates the testing and maintenance of 18 different open-source projects that implement distributed ledgers. We perform a manual inspection of test artefacts and mine the history of commits, issues and contributors of the chosen projects to understand the landscape of testing and maintenance in these projects. Our findings suggest that unit and integration tests are present in most projects, they do not follow a holistic system testing approach. Moreover, projects rely on a small team of core contributors (5 on average). While the projects are continuously maintained, larger changes are uncommon. Our results can be used for benchmarking and pinpointing areas of improvement for the development of distributed ledgers.
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| 3. |
- Dobslaw, Felix, 1983-
(författare)
-
A Parameter Tuning Framework for Metaheuristics Based on Design of Experiments and Artificial Neural Networks
- 2010
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Ingår i: Proceeding of the International Conference on Computer Mathematics and Natural Computing 2010. - : WASET. ; 64, s. 213-216
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Konferensbidrag (refereegranskat)abstract
- In this paper, a framework for the simplification andstandardization of metaheuristic related parameter tuning by applyinga four phase methodology, utilizing Design of Experiments andArtificial Neural Networks, is presented. Metaheuristics are multipurposeproblem solvers that are utilized on computational optimizationproblems for which no efficient problem-specific algorithmexists. Their successful application to concrete problems requires thefinding of a good initial parameter setting, which is a tedious andtime-consuming task. Recent research reveals the lack of approachwhen it comes to this so called parameter tuning process. In themajority of publications, researchers do have a weak motivation fortheir respective choices, if any. Because initial parameter settingshave a significant impact on the solutions quality, this course ofaction could lead to suboptimal experimental results, and therebya fraudulent basis for the drawing of conclusions.
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| 4. |
- Dobslaw, Felix, 1983-
(författare)
-
An experimental study on robust parameter settings
- 2010
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Ingår i: Proceedings of the 12th annual conference comp on Genetic and evolutionary computation. - New York, NY, USA : ACM Press. - 9781450300735 ; , s. 1999-2002
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Konferensbidrag (refereegranskat)abstract
- That there is no best initial parameter setting for a metaheuristicon all optimization problems is a proven fact (nofree lunch theorem). This paper studies the applicability ofso called robust parameter settings for combinatorial optimizationproblems. Design of Experiments supported parameterscreening had been carried out, analyzing a discreteParticle Swarm Optimization algorithm on three demographicallyvery dissimilar instances of the Traveling SalesmenProblem. First experimental results indicate that parametersettings produce varying performance quality forthe three instances. The robust parameter setting is outperformedin two out of three cases. The results are evensignicantly worse when considering quality/time trade-o.A methodology for problem generalization is referred to asa possible solution.
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| 5. |
- Dobslaw, Felix, 1983-, et al.
(författare)
-
An Object-Oriented Model in Support of Context Aware Mobile Applications
- 2010
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Ingår i: Mobile Wireless Middleware, Operating Systems, and Applications. - Berlin Hedielberg : Springer Verlag. - 9783642177576
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Konferensbidrag (refereegranskat)abstract
- Intelligent and context-aware mobile services require users and applications to share information and utilize services from remote locations. Thus, context information from the users must be structured and be accessible to applications running in end-devices. In response to this challenge, we present a shared object-oriented meta model for a persistent agent environment. The approach enables agents to be context aware facilitating the creation of ambient intelligence demonstrated by a sensor-based scenario. The agents are context-aware as agent actions are based upon sensor information, social information, and the behavior of co-agents.
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| 6. |
- Dobslaw, Felix, 1983-, et al.
(författare)
-
Automated black-box boundary value detection
- 2023
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Ingår i: PeerJ Computer Science. - : PeerJ. - 2376-5992. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Software systems typically have an input domain that can be subdivided into sub-domains, each of which generates similar or related outputs. Testing it on the boundaries between these sub-domains is critical to ensure high-quality software. Therefore, boundary value analysis and testing have been a fundamental part of the software testing toolbox for a long time and are typically taught early to software engineering students. Despite its many argued benefits, boundary value analysis for a given software specification or application is typically described in abstract terms. This allows for variation in how testers apply it and in the benefits they see. Additionally, its adoption has been limited since it requires a specification or model to be analysed. We propose an automated black-box boundary value detection method to support software testers in performing systematic boundary value analysis. This dynamic method can be utilized even without a specification or model. The proposed method is based on a metric referred to as the program derivative, which quantifies the level of boundariness of test inputs. By combining this metric with search algorithms, we can identify and rank pairs of inputs as good boundary candidates, i.e., inputs that are in close proximity to each other but with outputs that are far apart. We have implemented the AutoBVA approach and evaluated it on a curated dataset of example programs. Furthermore, we have applied the approach broadly to a sample of 613 functions from the base library of the Julia programming language. The approach could identify boundary candidates that highlight diverse boundary behaviours in over 70% of investigated systems under test. The results demonstrate that even a simple variant of the program derivative, combined with broad sampling and search over the input space, can identify interesting boundary candidates for a significant portion of the functions under investigation. In conclusion, we also discuss the future extension of the approach to encompass more complex systems under test cases and datatypes.
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| 7. |
- Dobslaw, Felix, 1983-
(författare)
-
Automatic Instance-based Tailoring of Parameter Settings for Metaheuristics
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many industrial problems in various fields, such as logistics, process management, orproduct design, can be formalized and expressed as optimization problems in order tomake them solvable by optimization algorithms. However, solvers that guarantee thefinding of optimal solutions (complete) can in practice be unacceptably slow. Thisis one of the reasons why approximative (incomplete) algorithms, producing near-optimal solutions under restrictions (most dominant time), are of vital importance.Those approximative algorithms go under the umbrella term metaheuristics, each of which is more or less suitable for particular optimization problems. These algorithmsare flexible solvers that only require a representation for solutions and an evaluation function when searching the solution space for optimality.What all metaheuristics have in common is that their search is guided by certain control parameters. These parameters have to be manually set by the user andare generally problem and interdependent: A setting producing near-optimal resultsfor one problem is likely to perform worse for another. Automating the parameter setting process in a sophisticated, computationally cheap, and statistically reliable way is challenging and a significant amount of attention in the artificial intelligence and operational research communities. This activity has not yet produced any major breakthroughs concerning the utilization of problem instance knowledge or the employment of dynamic algorithm configuration.The thesis promotes automated parameter optimization with reference to the inverse impact of problem instance diversity on the quality of parameter settings with respect to instance-algorithm pairs. It further emphasizes the similarities between static and dynamic algorithm configuration and related problems in order to show how they relate to each other. It further proposes two frameworks for instance-based algorithm configuration and evaluates the experimental results. The first is a recommender system for static configurations, combining experimental design and machine learning. The second framework can be used for static or dynamic configuration,taking advantage of the iterative nature of population-based algorithms, which is a very important sub-class of metaheuristics.A straightforward implementation of framework one did not result in the expected improvements, supposedly because of pre-stabilization issues. The second approach shows competitive results in the scenario when compared to a state-of-the-art model-free configurator, reducing the training time by in excess of two orders of magnitude.
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| 8. |
- Dobslaw, Felix, 1983, et al.
(författare)
-
Boundary Value Exploration for Software Analysis
- 2020
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Ingår i: Proceedings - 2020 IEEE 13th International Conference on Software Testing, Verification and Validation Workshops, ICSTW 2020. - : IEEE. ; , s. 346-353
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Konferensbidrag (refereegranskat)abstract
- For software to be reliable and resilient, it is widely accepted that tests must be created and maintained alongside the software itself. One safeguard from vulnerabilities and failures in code is to ensure correct behavior on the boundaries between subdomains of the input space. So-called boundary value analysis (BVA) and boundary value testing (BVT) techniques aim to exercise those boundaries and increase test effectiveness. However, the concepts of BVA and BVT themselves are not generally well defined, and it is not clear how to identify relevant sub-domains, and thus the boundaries delineating them, given a specification. This has limited adoption and hindered automation. We clarify BVA and BVT and introduce Boundary Value Exploration (BVE) to describe techniques that support them by helping to detect and identify boundary inputs. Additionally, we propose two concrete BVE techniques based on information-theoretic distance functions: (i) an algorithm for boundary detection and (ii) the usage of software visualization to explore the behavior of the software under test and identify its boundary behavior. As an initial evaluation, we apply these techniques on a much used and well-tested date handling library. Our results reveal questionable behavior at boundaries highlighted by our techniques. In conclusion, we argue that the boundary value exploration that our techniques enable is a step towards automated boundary value analysis and testing, which can foster their wider use and improve test effectiveness and efficiency.
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| 9. |
- Dobslaw, Felix, 1983-
(författare)
-
End-to-End Quality of Service Guarantees for Wireless Sensor Networks
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wireless sensor networks have been a key driver of innovation and societal progressover the last three decades. They allow for simplicity because they eliminate ca-bling complexity while increasing the flexibility of extending or adjusting networksto changing demands. Wireless sensor networks are a powerful means of fillingthe technological gap for ever-larger industrial sites of growing interconnection andbroader integration. Nonetheless, the management of wireless networks is difficultin situations wherein communication requires application-specific, network-widequality of service guarantees. A minimum end-to-end reliability for packet arrivalclose to 100% in combination with latency bounds in the millisecond range must befulfilled in many mission-critical applications.The problem addressed in this thesis is the demand for algorithmic support forend-to-end quality of service guarantees in mission-critical wireless sensor networks.Wireless sensors have traditionally been used to collect non-critical periodic read-ings; however, the intriguing advantages of wireless technologies in terms of theirflexibility and cost effectiveness justify the exploration of their potential for controland mission-critical applications, subject to the requirements of ultra-reliable com-munication, in harsh and dynamically changing environments such as manufactur-ing factories, oil rigs, and power plants.This thesis provides three main contributions in the scope of wireless sensor net-works. First, it presents a scalable algorithm that guarantees end-to-end reliabilitythrough scheduling. Second, it presents a cross-layer optimization/configurationframework that can be customized to meet multiple end-to-end quality of servicecriteria simultaneously. Third, it proposes an extension of the framework used toenable service differentiation and priority handling. Adaptive, scalable, and fast al-gorithms are proposed. The cross-layer framework is based on a genetic algorithmthat assesses the quality of service of the network as a whole and integrates the phys-ical layer, medium access control layer, network layer, and transport layer.Algorithm performance and scalability are verified through numerous simula-tions on hundreds of convergecast topologies by comparing the proposed algorithmswith other recently proposed algorithms for ensuring reliable packet delivery. Theresults show that the proposed SchedEx scheduling algorithm is both significantlymore scalable and better performing than are the competing slot-based schedulingalgorithms. The integrated solving of routing and scheduling using a genetic al-vvigorithm further improves on the original results by more than 30% in terms of la-tency. The proposed framework provides live graphical feedback about potentialbottlenecks and may be used for analysis and debugging as well as the planning ofgreen-field networks.SchedEx is found to be an adaptive, scalable, and fast algorithm that is capa-ble of ensuring the end-to-end reliability of packet arrival throughout the network.SchedEx-GA successfully identifies network configurations, thus integrating the rout-ing and scheduling decisions for networks with diverse traffic priority levels. Fur-ther, directions for future research are presented, including the extension of simula-tions to experimental work and the consideration of alternative network topologies.
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| 10. |
- Dobslaw, Felix, 1983-, et al.
(författare)
-
End-to-End Reliability-aware Scheduling for Wireless Sensor Networks
- 2016
-
Ingår i: IEEE Transactions on Industrial Informatics. - 1551-3203 .- 1941-0050. ; 12:2, s. 758-767
-
Tidskriftsartikel (refereegranskat)abstract
- Wireless Sensor Networks (WSN) are gaining popularity as a flexible and economical alternative to field-bus installations for monitoring and control applications. For missioncritical applications, communication networks must provide endto- end reliability guarantees, posing substantial challenges for WSN. Reliability can be improved by redundancy, and is often addressed on the MAC layer by re-submission of lost packets, usually applying slotted scheduling. Recently, researchers have proposed a strategy to optimally improve the reliability of a given schedule by repeating the most rewarding slots in a schedule incrementally until a deadline. This Incrementer can be used with most scheduling algorithms but has scalability issues which narrows its usability to offline calculations of schedules, for networks that are rather static. In this paper, we introduce SchedEx, a generic heuristic scheduling algorithm extension which guarantees a user-defined end-to-end reliability. SchedEx produces competitive schedules to the existing approach, and it does that consistently more than an order of magnitude faster. The harsher the end-to-end reliability demand of the network, the better SchedEx performs compared to the Incrementer. We further show that SchedEx has a more evenly distributed improvement impact on the scheduling algorithms, whereas the Incrementer favors schedules created by certain scheduling algorithms.
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