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  • 51.
    Aghighi, Meysam
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Jonsson, Peter
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Ståhlberg, Simon
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
    Tractable Cost-Optimal Planning over Restricted Polytree Causal Graphs2015Ingår i: Proceedings of the Twenty-Ninth AAAI Conference on Artificial Intelligence, AAAI Press, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    Causal graphs are widely used to analyze the complexity of planning problems. Many tractable classes have been identified with their aid and state-of-the-art heuristics have been derived by exploiting such classes. In particular, Katz and Keyder have studied causal graphs that are hourglasses (which is a generalization of forks and inverted-forks) and shown that the corresponding cost-optimal planning problem is tractable under certain restrictions. We continue this work by studying polytrees (which is a generalization of hourglasses) under similar restrictions. We prove tractability of cost-optimal planning by providing an algorithm based on a novel notion of variable isomorphism. Our algorithm also sheds light on the k-consistency procedure for identifying unsolvable planning instances. We speculate that this may, at least partially, explain why merge-and-shrink heuristics have been successful for recognizing unsolvable instances.

  • 52.
    Aguilar, Xavier
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz).
    Towards Scalable Performance Analysis of MPI Parallel Applications2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

      A considerably fraction of science discovery is nowadays relying on computer simulations. High Performance Computing  (HPC) provides scientists with the means to simulate processes ranging from climate modeling to protein folding. However, achieving good application performance and making an optimal use of HPC resources is a heroic task due to the complexity of parallel software. Therefore, performance tools  and runtime systems that help users to execute  applications in the most optimal way are of utmost importance in the landscape of HPC.  In this thesis, we explore different techniques to tackle the challenges of collecting, storing, and using  fine-grained performance data. First, we investigate the automatic use of real-time performance data in order to run applications in an optimal way. To that end, we present a prototype of an adaptive task-based runtime system that uses real-time performance data for task scheduling. This runtime system has a performance monitoring component that provides real-time access to the performance behavior of anapplication while it runs. The implementation of this monitoring component is presented and evaluated within this thesis. Secondly, we explore lossless compression approaches  for MPI monitoring. One of the main problems that  performance tools face is the huge amount of fine-grained data that can be generated from an instrumented application. Collecting fine-grained data from a program is the best method to uncover the root causes of performance bottlenecks, however, it is unfeasible with extremely parallel applications  or applications with long execution times. On the other hand, collecting coarse-grained data is scalable but  sometimes not enough to discern the root cause of a performance problem. Thus, we propose a new method for performance monitoring of MPI programs using event flow graphs. Event flow graphs  provide very low overhead in terms of execution time and  storage size, and can be used to reconstruct fine-grained trace files of application events ordered in time.

  • 53.
    Aguilar, Xavier
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz).
    Fürlinger, Karl
    Ludwig-Maximilians-Universitat (LMU).
    Laure, Erwin
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz).
    MPI Trace Compression Using Event Flow Graphs2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Understanding how parallel applications behave is crucial for using high-performance computing (HPC) resources efficiently. However, the task of performance analysis is becoming increasingly difficult due to the growing complexity of scientific codes and the size of machines. Even though many tools have been developed over the past years to help in this task, current approaches either only offer an overview of the application discarding temporal information, or they generate huge trace files that are often difficult to handle.

    In this paper we propose the use of event flow graphs for monitoring MPI applications, a new and different approach that balances the low overhead of profiling tools with the abundance of information available from tracers. Event flow graphs are captured with very low overhead, require orders of magnitude less storage than standard trace files, and can still recover the full sequence of events in the application. We test this new approach with the NERSC-8/Trinity Benchmark suite and achieve compression ratios up to 119x.

  • 54.
    Aguilar, Xavier
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz).
    Fürlinger, Karl
    Laure, Erwin
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz).
    Visual MPI Performance Analysis using Event Flow Graphs2015Ingår i: Procedia Computer Science, ISSN 1877-0509, E-ISSN 1877-0509, Vol. 51, 1353-1362 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Event flow graphs used in the context of performance monitoring combine the scalability and low overhead of profiling methods with lossless information recording of tracing tools. In other words, they capture statistics on the performance behavior of parallel applications while pre- serving the temporal ordering of events. Event flow graphs require significantly less storage than regular event traces and can still be used to recover the full ordered sequence of events performed by the application.  In this paper we explore the usage of event flow graphs in the context of visual performance analysis. We show that graphs can be used to quickly spot performance problems, helping to better understand the behavior of an application. We demonstrate our performance analysis approach with MiniFE, a mini-application that mimics the key performance aspects of finite- element applications in High Performance Computing (HPC).

  • 55.
    Aguilar, Xavier
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz).
    Laure, Erwin
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz).
    Fürlinger, Karl
    Ludwig-Maximilians-Universität München.
    Online Performance Data Introspection with IPM2014Ingår i: Proceedings of the 15th IEEE International Conference on High Performance Computing and Communications (HPCC 2013), IEEE Computer Society, 2014, 728-734 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Exascale systems will be heterogeneous architectures with multiple levels of concurrency and energy constraints. In such a complex scenario, performance monitoring and runtime systems play a major role to obtain good application performance and scalability. Furthermore, online access to performance data becomes a necessity to decide how to schedule resources and orchestrate computational elements: processes, threads, tasks, etc. We present the Performance Introspection API, an extension of the IPM tool that provides online runtime access to performance data from an application while it runs. We describe its design and implementation and show its overhead on several test benchmarks. We also present a real test case using the Performance Introspection API in conjunction with processor frequency scaling to reduce power consumption.

  • 56.
    Aguilar, Xavier
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz). KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Schliephake, Michael
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz). KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Parallelldatorcentrum, PDC. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Vahtras, Olav
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Parallelldatorcentrum, PDC. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Gimenez, Judit
    Laure, Erwin
    KTH, Skolan för datavetenskap och kommunikation (CSC), High Performance Computing and Visualization (HPCViz). KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Parallelldatorcentrum, PDC. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Scalability analysis of Dalton, a molecular structure program2013Ingår i: Future generations computer systems, ISSN 0167-739X, E-ISSN 1872-7115, Vol. 29, nr 8, 2197-2204 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dalton is a molecular electronic structure program featuring common methods of computational chemistry that are based on pure quantum mechanics (QM) as well as hybrid quantum mechanics/molecular mechanics (QM/MM). It is specialized and has a leading position in calculation of molecular properties with a large world-wide user community (over 2000 licenses issued). In this paper, we present a performance characterization and optimization of Dalton. We also propose a solution to avoid the master/worker design of Dalton to become a performance bottleneck for larger process numbers. With these improvements we obtain speedups of 4x, increasing the parallel efficiency of the code and being able to run in it in a much bigger number of cores.

  • 57.
    Ahlgren, Simon
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
    Aini, Daniel
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
    Conversion and Analysis of Telemetric Data from the CCSDS Standard2017Självständigt arbete på grundnivå (högskoleexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [en]

    When communicating with spacecrafts, the international standard is to use the protocols defined by CCSDS. In this study, the Space Packet Protocol from CCSDS is converted to the Digital Recording Standard used in aviation. The goal of the study is to find out in what way such a conversion can be made, as well as analyzing the efficiency of different packing methods for the Digital Recording Standard. An application is developed in order to perform the conversion, and the performance of said application is profiled using different packet sizes. In the end the results are evaluated and an optimal packet size is found in terms of runtime and memory usage. In the end we conclude that a packet size of 216 bytes is best when prioritizing speed, and a packet size of 219 bytes is best when prioritizing memory.

  • 58.
    Ahlén, Richard
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Grönholm, Robin
    Mälardalens högskola, Akademin för innovation, design och teknik.
    En analys av ljudlatens i Windows 10 på tillgängliga enheter2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Den här rapporten beskriver ett projekt utfört av två studenter på Mälardalens högskola i kursen DVA331. Syftet med projektet var att undersöka om det gick att få ned ljudlatensen på enheter med Windows 10 till den nivå som är möjlig på iOS. Anledningen till denna undersökning var för att Windows 10 har kommit med en API som stödjer låglatens-ljud. Undersökningen utfördes på en iPhone 4S, iPhone 6, Nokia Lumia 720 och Nokia Lumia 920 med hjälp av en kontaktmikrofon som sattes på telefonen. 50 mätningar gjordes per version av en testapplikation implementerad för de båda operativsystemen. Med mikrofonen och ljudhanteringsprogrammet Audacity kunde tiden mätas mellan det att pekytan berörs och det att ljudet spelas upp. Mätningarna visade att iOS fortfarande var betydligt snabbare än Windows 10 och att Windows 10 är långt över den gräns som är acceptabel vid användande av responsiv ljudhantering. Efterforskning visade att mätningarnas resultat berodde på att Lumia-enheterna hade en lång inmatningslatens. Användartester gjordes på 10 försökspersoner där återkopplingen visade att latensen på Windows 10-enheterna var mycket längre än iOS. Slutsatsen var att Lumia-enheterna i fråga inte är lämpliga för responsiva ljudapplikationer men att Windows 10-enheter med lägre inmatningslatens som är bättre lämpade och att nya mätningar bör göras för att bedöma om detta är fallet.

  • 59.
    Ahmadi, Lina
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Green Driving Application: Eco Driving2016Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Eco-driving has acquired great importance in recent years because it is a way to reduce energy consumption that can be applied to any type of vehicle. However, for these rules to be applied requires a process of continuous learning and motivation. For this reason many eco-driving assistants have emerged.

    This paper presents Green Driving, a driver safety app for Android that detects inattentive driving behaviors and gives corresponding feedback to drivers, scoring their driving and alerting them in case their behaviors are unsafe.  It’s about changing a person’s driving behavior by providing some kind of advice to the driver.  I have worked on an algorithm that is meant to reduce the fuel consumption of users. The algorithm is deployed in an android application.

    This application “Green Driving” is aimed at users with cars. It is basically like an assistant, suggesting the user when he should make the right gear changes, when to increase/decrease speed and avoids hard braking and rapid acceleration and etc. It is in order to drive economically, ecologic and in turn save money and safety. This is a smart way of letting a user drive economically and ecologic since almost everyone has an Android smartphone now. 

  • 60.
    Ahmed, Bestoun
    et al.
    Istituto Dalle Molle di Studi sullIntelligenza Artificiale (IDSIA), Switzerland.
    Gambardella, Luca
    Istituto Dalle Molle di Studi sullIntelligenza Artificiale (IDSIA), Switzerland.
    Afzal, Wasif
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Zamli, Kamal
    University Malaysia Pahang, Gambang, Malaysia.
    Handling Constraints in Combinatorial Interaction Testing in the Presence of Multi Objective Particle Swarm and Multithreading2017Ingår i: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 86, nr 01, 20-36 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Combinatorial strategies have received a lot of attention lately as a result of their diverse applications in areas of research, particularly in software engineering. In its simple form, a combinatorial strategy can reduce several input parameters (configurations) of a system into a small set of these parameters based on their interaction (combination). However, in practice, the input configurations of software systems are subjected to constraints, especially highly configurable systems. To implement this feature within a strategy, many difficulties arise for construction. While there are many combinatorial interaction testing strategies nowadays, few of them support constraints. This paper presents a new strategy, called Octopus to construct a combinatorial interaction test suites with the presence of constraints. The design and algorithms are provided in the paper in detail. The strategy is inspired by the behaviour of octopus to search for the optimal solution using multi-threading mechanism. To overcome the multi judgement criteria for an optimal solution, the multi-objective particle swarm optimisation is used. The strategy and its algorithms are evaluated extensively using different benchmarks and comparisons. The evaluation results showed the efficiency of each algorithm in the strategy. The benchmarking results also showed that Octopus can generate test suites efficiently as compared to state-of-the-art strategies.

  • 61.
    Ahmed, Bestoun
    et al.
    Czech Technical University, Czech Republic.
    Zamli, Kamal
    University Malaysia Pahang, Gambang, Malaysia..
    Afzal, Wasif
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bures, Miroslav
    Czech Technical University, Czech Republic.
    Constrained Interaction Testing: A Systematic Literature Study2017Ingår i: IEEE Access, E-ISSN 2169-3536, IEEE Access, ISSN 2169-3536, Vol. PP, nr 99Artikel, recension (Övrigt vetenskapligt)
    Abstract [en]

    Interaction testing can be used to effectively detect faults that are otherwise difficult to find by other testing techniques. However, in practice, the input configurations of software systems are subjected to constraints, especially in the case of highly configurable systems. Handling constraints effectively and efficiently in combinatorial interaction testing is a challenging problem. Nevertheless, researchers have attacked this challenge through different techniques, and much progress has been achieved in the past decade. Thus, it is useful to reflect on the current achievements and shortcomings and to identify potential areas of improvements. This paper presents the first comprehensive and systematic literature study to structure and categorize the research contributions for constrained interaction testing. Following the guidelines of conducting a literature study, the relevant data is extracted from a set of 103 research papers belonging to constrained interaction testing. The topics addressed in constrained interaction testing research are classified into four categories of constraint test generation, application, generation & application and model validation studies. The papers within each of these categories are extensively reviewed. Apart from answering several other research questions, this study also discusses the applications of constrained interaction testing in several domains such as software product lines, fault detection & characterization, test selection, security and GUI testing. The study ends with a discussion of limitations, challenges and future work in the area.

  • 62. Ahmed, J.
    et al.
    Johnsson, A.
    Yanggratoke, Rerngvit
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre. KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät.
    Ardelius, J.
    Flinta, C.
    Stadler, Rolf
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Predicting SLA conformance for cluster-based services using distributed analytics2016Ingår i: Proceedings of the NOMS 2016 - 2016 IEEE/IFIP Network Operations and Management Symposium, IEEE conference proceedings, 2016, 848-852 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Service assurance for the telecom cloud is a challenging task and is continuously being addressed by academics and industry. One promising approach is to utilize machine learning to predict service quality in order to take early mitigation actions. In previous work we have shown how to predict service-level metrics, such as frame rate for a video application on the client side, from operational data gathered at the server side. This gives the service provider early indications on whether the platform can support the current load demand. This paper extends previous work by addressing scalability issues for cluster-based services. Operational data being generated in large volumes, from several sources, and at high velocity puts strain on computational and communication resources. We propose and evaluate a distributed machine learning system based on the Winnow algorithm to tackle scalability issues, and then compare the new distributed solution with the previously proposed centralized solution. We show that network overhead and computational execution time is substantially reduced while maintaining high prediction accuracy making it possible to achieve real-time service quality predictions in large systems.

  • 63.
    Ahmed, Mobyen Uddin
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    An Intelligent Healthcare Service to Monitor Vital Signs in Daily Life – A Case Study on Health-IoT2017Ingår i: International Journal of Engineering Research and Applications, ISSN 2248-9622, E-ISSN 2248-9622, Vol. 7, nr 3, 43-55 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Vital signs monitoring for elderly in daily life environment is a promising concept that efficiently can provide medical services to people at home. However, make the system self-served and functioning as personalized provision makes the challenge even larger. This paper presents a case study on a Health-IoT system where an intelligent healthcare service is developed to monitor vital signs in daily life. Here, a generic Health-IoT framework with a Clinical Decision Support System (CDSS) is presented. The generic framework is mainly focused on the supporting sensors, communication media, secure and safe data communication, cloud-based storage, and remote accesses of the data. The CDSS is used to provide a personalized report on persons’ health condition based on daily basis observation on vital signs. Six participants, from Spain (n=3) and Slovenia (n=3) have been using the proposed healthcare system for eight weeks (e.g. 300+ health measurements) in their home environments to monitor their health. The sensitivity, specificity and overall accuracy of the DSS’s classification are achieved as 90%, 97% and 96% respectively while k=2 i.e., top 2 most similar retrieved cases are considered. The initial user evaluation result demonstrates the feasibility and performance of the implemented system through the proposed framework.

  • 64.
    Ahmed, Mobyen Uddin
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Banaee, Hadi
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Health monitoring for elderly: an application using case-based reasoning and cluster analysis2013Ingår i: ISRN Artificial Intelligence, ISSN 2090-7435, E-ISSN 2090-7443, Vol. 2013, nr 2013, 1-11 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a framework to process and analyze data from a pulse oximeter which measures pulse rate and blood oxygen saturation from a set of individuals remotely. Using case-based reasoning (CBR) as the backbone to the framework, records are analyzed and categorized according to how well they are similar. Record collection has been performed using a personalized health profiling approach where participants wore a pulse oximeter sensor for a fixed period of time and performed specific activities for pre-determined intervals. Using a variety of feature extraction in time, frequency and time-frequency domains, and data processing techniques, the data is fed into a CBR system which retrieves most similar cases and generates alarm and flag according to the case outcomes. The system has been compared with an expert's classification and 90% match is achieved between the expert's and CBR classification. Again, considering the clustered measurements the CBR approach classifies 93% correctly both for the pulse rate and oxygen saturation. Along with the proposed methodology, this paper provides a basis for which the system can be used in analysis of continuous health monitoring and be used as a suitable method as in home/remote monitoring systems.

  • 65.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Begum, Shahina
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Catalina, Carlos Alberto
    2ITCL Polígono Industrial Villalonquéjar c/López Bravo, 70. 09001 BURGOS, Spain.
    Limonad, Lior
    Smart Wearable and IoT Solutions, IBM Research, Haifa, Israil.
    Hök, Bertil
    Hök Instrument AB, Sweden.
    Flumeri, Gianluca Di
    Cognitive States in Operative Environment, BrainSigns, Italy.
    Cloud-based Data Analytics on Human Factor Measurement to Improve Safer Transport2017Ingår i: 4th EAI International Conference on IoT Technologies for HealthCare HealthyIOT'17, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Improving safer transport includes individual and collective behavioural aspects and their interaction. A system that can monitor and evaluate the human cognitive and physical capacities based on human factor measurement is often beneficial to improve safety in driving condition. However, analysis and evaluation of human factor measurement i.e. Demographics, Behavioural and Physiological in real-time is challenging. This paper presents a methodology for cloud-based data analysis, categorization and metrics correlation in real-time through a H2020 project called SimuSafe. Initial implementation of this methodology shows a step-by-step approach which can handle huge amount of data with variation and verity in the cloud.

  • 66.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Begum, Shahina
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Funk, Peter
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Xiong, Ning
    Mälardalens högskola, Akademin för innovation, design och teknik.
    von Schéele, Bo
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A Three Phase Computer Assisted Biofeedback Training System Using Case-Based Reasoning2008Ingår i: Proc. 9th European Conference on Case-based Reasoning, 2008, 57-68 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Biofeedback is a method gaining increased interest and showing good results for a number of physical and psychological problems. Biofeedback training is mostly guided by an experienced clinician and the results largely rely on the clinician's competence. In this paper we propose a three phase computer assisted sensor-based biofeedback decision support system assisting less experienced clinicians, acting as second opinion for experienced clinicians. The three phase CBR framework is deployed to classify a patient, estimate initial parameters and to make recommendations for biofeedback training by retrieving and comparing with previous similar cases in terms of features extracted. The three phases work independently from each other. Moreover, fuzzy techniques are incorporated into our CBR system to better accommodate uncertainty in clinicians reasoning as well as decision analysis. All parts in the proposed framework have been implemented and primarily validated in a prototypical system. The initial result shows how the three phases functioned with CBR technique to assist biofeedback training. Eventually the system enables the clinicians to allow a patient to train himself/herself unsupervised.

  • 67.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Begum, Shahina
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Funk, Peter
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Xiong, Ning
    Mälardalens högskola, Akademin för innovation, design och teknik.
    von Schéele, Bo
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Case-based Reasoning for Diagnosis of Stress using Enhanced Cosine and Fuzzy Similarity2008Ingår i: Case-based Reasoning for Diagnosis of Stress using Enhanced Cosine and Fuzzy Similarity, ISSN 1867-366X, Vol. 1, 3-19 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Intelligent analysis of heterogeneous data and information sources for efficient decision support presents an interesting yet challenging task in clinical envi-ronments. This is particularly the case in stress medicine where digital patient re-cords are becoming popular which contain not only lengthy time series measurements but also unstructured textual documents expressed in form of natural languages. This paper develops a hybrid case-based reasoning system for stress di-agnosis which is capable of coping with both numerical signals and textual data at the same time. The total case index consists of two sub-parts corresponding to signal and textual data respectively. For matching of cases on the signal aspect we present a fuzzy similarity matching metric to accommodate and tackle the imprecision and uncertainty in sensor measurements. Preliminary evaluations have revealed that this fuzzy matching algorithm leads to more accurate similarity estimates for improved case ranking and retrieval compared with traditional distance-based matching crite-ria. For evaluation of similarity on the textual dimension we propose an enhanced cosine matching function augmented with related domain knowledge. This is im-plemented by incorporating Wordnet and domain specific ontology into the textual case-based reasoning process for refining weights of terms according to available knowledge encoded therein. Such knowledge-based reasoning for matching of tex-tual cases has empirically shown its merit in improving both precision and recall of retrieved cases with our initial medical databases. Experts in the domain are very positive to our system and they deem that it will be a valuable tool to foster wide-spread experience reuse and transfer in the area of stress diagnosis and treatment.

  • 68.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lindén, Maria
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    A Generic System-level Framework for Self-Serve Health Monitoring System through Internet of Things(IoT)2015Ingår i: Studies in Health Technology and Informatics, Volume 211: Proceedings of the 12th International Conference on Wearable Micro and Nano Technologies for Personalized Health, 2–4 June 2015, Västerås, Sweden, 2015, Vol. 211, 305-307 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sensor data are traveling from sensors to a remote server, data is analysed remotely in a distributed manner, and health status of a user is presented in real-time. This paper presents a generic system-level framework for a self-served health monitoring system through the Internet of Things (IoT) to facilities an efficient sensor data management.

  • 69.
    Ahmed, Mobyen Uddin
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Islam, Asif Moinul
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    A case-based patient identification system using pulseoximeter and a personalized health profile2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes a case-based system framework in order to identify patient using their health parameters taken with physiological sensors. It combines a personalized health profiling protocol with a Case-Based Reasoning (CBR) approach. The personalized health profiling helps to determine a number of individual parameters which are important inputs for a clinician to make the final diagnosis and treatment plan. The proposed system uses a pulse oximeter that measures pulse rate and blood oxygen saturation. The measurements are taken through an android application in a smart phone which is connected with the pulseoximeter and bluetooth communication. The CBR approach helps clinicians to make a diagnosis, classification and treatment plan by retrieving the most similar previous case. The case may also be used to follow the treatment progress. Here, the cases are formulated with person’s contextual information and extracted features from sensor signal measurements. The features are extracted considering three domain analysis:1) time domain features using statistical measurement, 2) frequency domain features applying Fast Fourier Transform (FFT), and 3) time-frequency domain features applying Discrete Wavelet Transform (DWT). The initial result is acceptable that shows the advancement of the system while combining the personalized health profiling together with CBR.

  • 70.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Olsson, Erik
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Funk, Peter
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Xiong, Ning
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    A Case-Based Reasoning System for Knowledge and Experience Reuse2007Ingår i: Proceedings of the 24th annual workshop of the Swedish Artificial Intelligence Society, 2007, 70-80 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Experience is one of the most valuable assets technicians and engineer have and may have been collected during many years and both from successful solutions as well as from very costly mistakes. Unfortunately industry rarely uses a systematic approach for experience reuse. This may be caused by the lack of efficient tools facilitating experience distribution and reuse. We propose a case-based approach and tool to facilitate experience reuse more systematically in industry. It is important that such a tool allows the technicians to give the problem case in a flexible way to increase acceptance and use. The proposed tool enables more structured handling of experience and is flexible and can be adapted to different situations and problems. The user is able to input text in a structured way and possibly in combination with other numeric or symbolic features. The system is able to identify and retrieve relevant similar experiences for reuse.

  • 71.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Olsson, Erik
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Funk, Peter
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Xiong, Ning
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Efficient Condition Monitoring and Diagnosis Using a Case-Based Experience Sharing System2007Ingår i: The 20th International Congress and Exhibition on Condition Monitoring and Diagnostics Engineering Management, COMADEM 2007, Faro, Portugal, 2007, 305-314 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Industry has to adjust quickly to changes in their surroundings, for example reducing staff during recession and increasing staff when the market demands it. These factors may cause rapid loss of experience, collected during many years, or require experienced staff to spend considerable resources in training new staff, instead of focusing on production. This is recognised as very costly for companies and organisations today and also reduces competitiveness and productivity. Condition Monitoring, diagnostics and selection of efficient preventive or corrective actions is a task that often requires a high degree of expertise. This expertise is often gained through sometimes very expensive mistakes and can take many years to acquire leading to a few skilled experts. When they are not available due to changes in staff or retirements the company often faces serious problems that may be very expensive, e.g. leading to a reduced productivity.

    If some deviation occurs in a machine, a fault report is often written; an engineer makes a diagnosis and may order spare parts to repair the machine. Fault report, spare parts, required time and statistics on performance after repair are often stored in different databases but so far not systematically reused. In this paper we present a Case-Based experience sharing system that enables reuse of experience in a more efficient way compared with what is mostly practiced in industry today. The system uses Case-Based-Reasoning (CBR) and limited Natural Language Processing. An important aspect of the experience management tool is that it is user-friendly and web-based to promote efficient experience sharing. The system should be able to handle both experiences that are only in house as well as sharing experience with other industries when there is no conflicting interest. Such a CBR based tool enables efficient experience gathering, management and reuse in production industries. The tool will facilitate the users with an interactive environment to communicate with each other for sharing their experiences. Depend on the user; the security level of the system will be varied to share knowledge among the collaborating companies.

    The system identifies the most relevant experiences to assess and resolve the current situation. The experience is stored and retrieved as a case in the collaborative space where experience from various companies may have been stored under many years. Reusing experience and avoiding expensive mistakes will increase the participating companies' competitiveness and also transfer valuable experience to their employees. One of the benefits is also the opportunity and facility to identify people with similar tasks and problems at different companies and enable them to share their experience, e.g. if a technician has solved a similar problem recently and is in the near, the most efficient solution may be to call the expert and ask for assistance. In future, one may access this tool through his/her mobile device via wireless or mobile communications using Global Positioning System, GPS, enables the system to suggest experts nearby, willing and able to share the knowledge and quickly assist in resolve the problem.

  • 72.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Westin, Jerker
    Nyholm, Dag
    Dougherty, Mark
    Groth, Torgny
    A fuzzy rule-based decision support system for Duodopa treatment in Parkinson2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    A decision support system (DSS) was implemented based on a fuzzy logic inference system (FIS) to provide assistance in dose alteration of Duodopa infusion in patients with advanced Parkinson's disease, using data from motor state assessments and dosage. Three-tier architecture with an object oriented approach was used. The DSS has a web enabled graphical user interface that presents alerts indicating non optimal dosage and states, new recommendations, namely typical advice with typical dose and statistical measurements. One data set was used for design and tuning of the FIS and another data set was used for evaluating performance compared with actual given dose. Overall goodness-of-fit for the new patients (design data) was 0.65 and for the ongoing patients (evaluation data) 0.98. User evaluation is now ongoing. The system could work as an assistant to clinical staff for Duodopa treatment in advanced Parkinson's disease.

  • 73.
    Ahmed, Tanvir Saif
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Markovic, Bratislav
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Distribuerade datalagringssystem för tjänsteleverantörer: Undersökning av olika användningsfall för distribuerade datalagringssystem2016Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Detta examensarbete handlar om undersökning av tre olika användningsfall inom datalagring; Cold Storage, High Performance Storage och Virtual Machine Storage. Rapporten har som syfte att ge en översikt över kommersiella distribuerade filsystem samt en djupare undersökning av distribuerade filsystem som bygger på öppen källkod och därmed hitta en optimal lösning för dessa användnings-fall. I undersökningen ingick att analysera och jämföra tidigare arbeten där jämförelser mellan pre-standamätningar, dataskydd och kostnader utfördes samt lyfta upp diverse funktionaliteter (snapshotting, multi-tenancy, datadeduplicering, datareplikering) som moderna distribuerade filsy-stem kännetecknas av. Både kommersiella och öppna distribuerade filsystem undersöktes. Även en kostnadsuppskattning för kommersiella och öppna distribuerade filsystem gjordes för att ta reda på lönsamheten för dessa två typer av distribuerat filsystem.Efter att jämförelse och analys av olika tidigare arbeten utfördes, visade sig att det öppna distribue-rade filsystemet Ceph lämpade sig bra som en lösning utifrån kraven som sattes som mål för High Performance Storage och Virtual Machine Storage. Kostnadsuppskattningen visade att det var mer lönsamt att implementera ett öppet distribuerat filsystem. Denna undersökning kan användas som en vägledning vid val mellan olika distribuerade filsystem.

  • 74. Aid Kalle Dunkel, Laura Viktorya Chrsitina Matthias Wißotzki
    et al.
    Sandkuhl, Kurt
    Högskolan i Jönköping, Tekniska Högskolan, JTH. Forskningsområde Informationsteknik.
    State of research in reuse of enterprise models: Systematic literature analysis of CAISE, EMMSAD, ICIS and INCOM2012Ingår i: Proceedings of the IADIS International Conference on Information Systems, 2012, 82-90 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The importance of managing organizational knowledge of enterprises has been recognized for decades. The systematic development and reuse of organizational knowledge is expected to improve the competitiveness of the enterprise. While the practice of “reuse” is common in general computer science there is still a lack of surveys in regard to reuse in enterprise modeling. This document reviews four different papers presented at information systems conferences over the last seven years: CAISE, EMMSAD, ICIS, and INCOM. Our analysis indicates that the majority of research is realized by case studies, theoretical frameworks and mostly on business process modeling aspects of enterprise models.

  • 75.
    Aisa, J.
    et al.
    Universidad de Zaragoza, Zaragoza, Spain .
    Fotouhi, Hossein
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Villarroel, J. L.
    Universidad de Zaragoza, Zaragoza, Spain .
    Almeida, L.
    University of Porto, Porto, Portugal.
    Soft real-time traffic communication in loaded Wireless Mesh Networks2016Ingår i: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS, 2016, Article number 7496503Konferensbidrag (Refereegranskat)
    Abstract [en]

    Industrial applications have been shifting towards wireless multi-hop networks in recent years due to their lower cost of deployment and reconfiguration compared with their wired counterparts. These wireless networks usually must support real-time communication to meet the application requirements. For this reason, Wireless Mesh Networks (WMNs) are potential candidates for industrial applications as they support a fixed infrastructure of static nodes for relaying packets. To meet the application demands, we modify the wireless chain network protocol (WICKPro) to support soft real-time traffic in WMNs with chain topologies over IEEE 802.11. We employ tele-operation of mobile robots as our case study, and perform extensive simulation and laboratory experiments. We show that the data delivery ratio is increased up to 42% in a scenario with 7 nodes, when the maximum end-to-end delay tolerated by the application is doubled. This is particularly suited to soft real-time applications that can trade longer delays by higher reliability. Moreover, when compared with a distributed priority-based token-passing protocol (RT-WMP), the lower overhead of WICKPro allows, in an error-free scenario, obtaining a throughput improvement of 33.42% on average.

  • 76.
    Aisa, Jesus
    et al.
    Universidad de Zaragoza, Zaragoza, Spain.
    Fotouhi, Hossein
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Almeida, Luis
    University of Porto, Portugal.
    Villarroel, José Luis
    Universidad de Zaragoza, Zaragoza, Spain.
    DoTHa - A Double-threshold Hand-off Algorithm for Managing Mobility in Wireless Mesh Networks2016Ingår i: 21st IEEE Conference on Emerging Technologies and Factory Automation ETFA'16, 2016, 7733511Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wireless communication will play an increasingly important role in future factory automation and process control, where the presence of mobile autonomous devices is expected to grow. However, wireless links are prone to errors due to shadowing and multi-path fading, which is even more severe in dynamic environments. These problems can be attenuated by using a mesh backbone to which mobile node connect to, using a hand-off algorithm. This solution is particularly important under real-time requirements typically found in factory automation. In this paper, we devise the Double-Threshold Hand-off (DoTHa) algorithm, a novel hand-off mechanism that triggers a hand-off in various environmental conditions. As a case study, we carry out the tele-operation of a mobile robot through a wireless mesh network in an indoor setting, using a wireless chain network protocol (WICKPro-SRT) that supports soft real-time traffic. We empirically compared DoTHa with two existing hand-off algorithms based on single and double hysteresis margin. The results revealed that DoTHa achieves Data Delivery Ratio (DDR) close to 100% whereas the single hysteresis-based hand-off suffers from frequent disconnections, dropping DDR to 88%. The double hysteresis-based hand-off shows higher ping-pong effect than DoTHa, doubling the number of hand-offs in some scenarios.

  • 77.
    Akalin, Neziha
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kiselev, Andrey
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kristoffersson, Annica
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Loutfi, Amy
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    An Evaluation Tool of the Effect of Robots in Eldercare on the Sense of Safety and Security2017Ingår i: Social Robotics: 9th International Conference, ICSR 2017, Tsukuba, Japan, November 22-24, 2017, Proceedings / [ed] Kheddar, A.; Yoshida, E.; Ge, S.S.; Suzuki, K.; Cabibihan, J-J:, Eyssel, F:, He, H., Springer International Publishing , 2017, 628-637 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The aim of the study presented in this paper is to develop a quantitative evaluation tool of the sense of safety and security for robots in eldercare. By investigating the literature on measurement of safety and security in human-robot interaction, we propose new evaluation tools. These tools are semantic differential scale questionnaires. In experimental validation, we used the Pepper robot, programmed in the way to exhibit social behaviors, and constructed four experimental conditions varying the degree of the robot’s non-verbal behaviors from no gestures at all to full head and hand movements. The experimental results suggest that both questionnaires (for the sense of safety and the sense of security) have good internal consistency.

  • 78. Akhmetova, D.
    et al.
    Kestor, G.
    Gioiosa, R.
    Markidis, Stefano
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsvetenskap och beräkningsteknik (CST).
    Laure, Erwin
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsvetenskap och beräkningsteknik (CST).
    On the application task granularity and the interplay with the scheduling overhead in many-core shared memory systems2015Ingår i: Proceedings - IEEE International Conference on Cluster Computing, ICCC, IEEE , 2015, 428-437 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Task-based programming models are considered one of the most promising programming model approaches for exascale supercomputers because of their ability to dynamically react to changing conditions and reassign work to processing elements. One question, however, remains unsolved: what should the task granularity of task-based applications be? Fine-grained tasks offer more opportunities to balance the system and generally result in higher system utilization. However, they also induce in large scheduling overhead. The impact of scheduling overhead on coarse-grained tasks is lower, but large systems may result imbalanced and underutilized. In this work we propose a methodology to analyze the interplay between application task granularity and scheduling overhead. Our methodology is based on three main points: 1) a novel task algorithm that analyzes an application directed acyclic graph (DAG) and aggregates tasks, 2) a fast and precise emulator to analyze the application behavior on systems with up to 1,024 cores, 3) a comprehensive sensitivity analysis of application performance and scheduling overhead breakdown. Our results show that there is an optimal task granularity between 1.2x10^4 and 10x10^4 cycles for the representative schedulers. Moreover, our analysis indicates that a suitable scheduler for exascale task-based applications should employ a best-effort local scheduler and a sophisticated remote scheduler to move tasks across worker threads.

  • 79.
    Akhmetova, Dana
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsvetenskap och beräkningsteknik (CST).
    Iakymchuk, Roman
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsvetenskap och beräkningsteknik (CST).
    Ekeberg, Örjan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsvetenskap och beräkningsteknik (CST).
    Laure, Erwin
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsvetenskap och beräkningsteknik (CST).
    Performance study of multithreaded MPI and Openmp tasking in a large scientific code2017Ingår i: Proceedings - 2017 IEEE 31st International Parallel and Distributed Processing Symposium Workshops, IPDPSW 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, 756-765 s., 7965119Konferensbidrag (Refereegranskat)
    Abstract [en]

    With a large variety and complexity of existing HPC machines and uncertainty regarding exact future Exascale hardware, it is not clear whether existing parallel scientific codes will perform well on future Exascale systems: they can be largely modified or even completely rewritten from scratch. Therefore, now it is important to ensure that software is ready for Exascale computing and will utilize all Exascale resources well. Many parallel programming models try to take into account all possible hardware features and nuances. However, the HPC community does not yet have a precise answer whether, for Exascale computing, there should be a natural evolution of existing models interoperable with each other or it should be a disruptive approach. Here, we focus on the first option, particularly on a practical assessment of how some parallel programming models can coexist with each other. This work describes two API combination scenarios on the example of iPIC3D [26], an implicit Particle-in-Cell code for space weather applications written in C++ and MPI plus OpenMP. The first scenario is to enable multiple OpenMP threads call MPI functions simultaneously, with no restrictions, using an MPI THREAD MULTIPLE thread safety level. The second scenario is to utilize the OpenMP tasking model on top of the first scenario. The paper reports a step-by-step methodology and experience with these API combinations in iPIC3D; provides the scaling tests for these implementations with up to 2048 physical cores; discusses occurred interoperability issues; and provides suggestions to programmers and scientists who may adopt these API combinations in their own codes.

  • 80.
    Akiki, Cesar
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för data-, elektro- och lantmäteriteknik.
    Torstensson, Daniel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för data-, elektro- och lantmäteriteknik.
    Hur routingtabellens storlek påverkar paketets fördröjning i en router eller L3 switch2017Självständigt arbete på grundnivå (högskoleexamen), 5 poäng / 7,5 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Internet växer hela tiden och fler enheter ökar för varje dag. I och med detta så ökar antalet routes i enheters routingtabeller och ju mer dessa ökar desto större påverkan har de på fördröjningen på en router eller lager3 switch. Eller har de verkligen det? I detta arbete har det tagits reda på om det finns någon märkbar skillnad i fördröjning på paketen i jämförelse till hur stor routingtabellen är och detta jämfört mellan en router och lager3 switch. Under arbetets gång har det används en dator som innehar två stycken nätverkskort och denna är kopplad till en nätverksenhet, router eller switch. Tre program som användes har varit till stor hjälp för att kunna utföra testerna; Wireshark, för att övervaka paketen samt tiden för paketen mellan de två nätverkskorten. Tftpd32, för att överföra enheternas konfigurationsfiler till och från datorn. Ostinato, används för att generera och skicka ut paket till nätverksenheten. De resultat som presenteras av testerna pekar mot att det inte finns en ökning i fördröjning när routingtabellen ökar. Detta är en upptäckt som utmanar tidigare studier som menar att en större routingtabell ökar fördröjningen av paketet.

  • 81.
    Akinola, Azeez Paul
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    chong, zhang
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Tunnel comparison between Generic Routing Encapsulation (GRE) and IP Security (IPSec)2012Självständigt arbete på grundnivå (högskoleexamen), 5 poäng / 7,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Since the introduction of networks, they have been used amongst home users, companies and organizations and most damage on the network is due to inappropriate security configurations. To secure networks, a protocol suite can be used to encrypt and authenticate all IP packets of a session. Therefore, this report will include the advantages and possible solution of some techniques used to offer increased network security such as scalability and data confidentiality. Captures of traffic sent using the two security techniques, IPSec/VPN and GRE-Tunnel will be monitored. The objective behind this project is to configure a network with these two different tunneling techniques and compare the security and network performance. The report also describes the security problems encountered by networks such as the ignorance of network users, vulnerabilities and the security of the devices.IPSecis a standard security protocol solution for TCP/IP, and it provides security through authentication, encryption and data integrity. GRE encapsulates packets and create a logical hub-and spoke topology of virtual point-to-point connections. The Jperf-tool is used to measure network performance and show specific details while another tool, Wireshark is used to analyze the information captured during transmission of data sent using IPSEC and GRE. The comparison further finds that IPSec-tunnel technique makes data transfers very secure but causes network performance disadvantages in comparison to a GRE solution.

  • 82.
    Al Mamun, Abdullah
    et al.
    Division of Software Engineering Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden.
    Berger, Christian
    Division of Software Engineering Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden.
    Hansson, Jörgen
    Högskolan i Skövde, Institutionen för informationsteknologi. Högskolan i Skövde, Forskningscentrum för Informationsteknologi.
    Explicating, Understanding and Managing Technical Debt from Self-Driving Miniature Car Projects2014Ingår i: Proceedings 2014 6th IEEE International Workshop on Managing Technical Debt: MTD 2014, Los Alamitos, CA: IEEE Computer Society, 2014, 11-18 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Technical debt refers to various weaknesses in the design or implementation of a system resulting from trade-offs during software development usually for a quick release. Accumulating such debt over time without reducing it can seriously hamper the reusability and maintainability of the software. The aim of this study is to understand the state of the technical debt in the development of self-driving miniature cars so that proper actions can be planned to reduce the debt to have more reusable and maintainable software. A case study on a selected feature from two self-driving miniature car development projects is performed to assess the technical debt. Additionally, an interview study is conducted involving the developers to relate the findings of the case study with the possible root causes. The result of the study indicates that "the lack of knowledge" is not the primary reason for the accumulation of technical debt from the selected code smells. The root causes are rather in factors like time pressure followed by issues related to software/hardware integration and incomplete refactoring as well as reuse of legacy, third party, or open source code.

  • 83.
    Alajrami, S.
    et al.
    Newcastle University, Newcastle-upon-Tyne, United Kingdom.
    Gallina, Barbara
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Romanovsky, A.
    Newcastle University, Newcastle-upon-Tyne, United Kingdom.
    EXE-SPEM: Towards cloud-based executable software process models2016Ingår i: MODELSWARD 2016 - Proceedings of the 4th International Conference on Model-Driven Engineering and Software Development, 2016, 517-526 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Executing software processes in the cloud can bring several benefits to software development. In this paper, we discuss the benefits and considerations of cloud-based software processes. EXE-SPEM is our extension of the Software and Systems Process Engineering (SPEM2.0) Meta-model to support creating cloud-based executable software process models. Since SPEM2.0 is a visual modelling language, we introduce an XML notation meta-model and mapping rules from EXE-SPEM to this notation which can be executed in a workflow engine. We demonstrate our approach by modelling an example software process using EXE-SPEM and mapping it to the XML notation. 

  • 84.
    Alajrami, S.
    et al.
    Newcastle University, Newcastle upon Tyne, United Kingdom .
    Gallina, Barbara
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Sljivo, Irfan
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Romanovsky, A.
    Newcastle University, Newcastle upon Tyne, United Kingdom .
    Isberg, Petter
    Mälardalens högskola.
    Towards cloud-based enactment of safety-related processes2016Ingår i: Lecture Notes in Computer Science, vol. 9922, 2016, 309-321 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Engineering safety-critical systems is a complex task which involves multiple stakeholders. It requires shared and scalable computation to systematically involve geographically distributed teams. The paper proposes a model-driven cloud-based enactment architecture automating safety-critical processes. This work adapts our previous work on cloud-based software engineering by enriching the architecture with an automatic support for generation of both, product-based safety arguments from failure logic analysis results and process-based arguments from the process model and the enactment data. The approach is demonstrated using a fragment of a process adapted from the aerospace domain. 

  • 85.
    Alajrami, Sami
    et al.
    Newcastle University, Newcastle upon Tyne, UK.
    Gallina, Barbara
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Romanovsky, Alexander
    Newcastle University, Newcastle upon Tyne, UK.
    Enabling GSD Task Allocation via Cloud-based Software Processes2017Ingår i: Software Engineering Research, Management and Applications SERA-2017, Springer, 2017, 179-192 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Allocating tasks to distributed sites in Global Software Development (GSD) projects is often done unsystematically and based on the personal experi- ence of project managers. Wrong allocation decisions increase the project’s risks as tasks have dependencies that are inherited by the distributed sites. Decision sup- port can help make the task allocation a more informed and systematic process. The challenges in allocating tasks to distributed sites exist because of three dis- tance dimensions between sites (geographical, temporal and cultural). An informed task allocation decision needs to consider these distances. Therefore, in this paper, we propose to integrate and semi-automate the calculation of an existing Global Distance Metric (GDM) into an architecture that supports executing cloud-based software processes. We analyze the potential of integrating the GDM into this archi- tecture and identify the needed extensions to the architecture.

  • 86.
    Alajrami, Sami
    et al.
    Newcasle University, UK.
    Gallina, Barbara
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. IS (Embedded Systems).
    Romanovsky, Alexander
    Newcasle University, UK.
    Enabling GSD Task Allocation via Cloud-based Software Processes2017Ingår i: International Journal of Networked and Distributed Computing, E-ISSN 2211-7946, Vol. 5, nr 4, 221-232 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Allocating tasks to distributed sites in Global Software Development (GSD) projects is often done unsystematically and based on the personal experience of project managers. Wrong allocation decisions increase the project’s risks as tasks have dependencies that are inherited by the distributed sites. Decision support can help make the task allocation a more informed and systematic process. The challenges in allocating tasks to distributed sites exist because of three distance dimensions between sites (geographical, temporal and cultural). An informed task allocation decision needs to consider these distances. Therefore, in this paper, we propose to integrate and semi-automate the calculation of an existing Global Distance Metric (GDM) into an architecture that supports executing cloud-based software processes. We analyze the potential of integrating the GDM into this architecture and identify the needed extensions to the architecture.

  • 87.
    Albayrak, Aras
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Automatic Pose and Position Estimation by Using Spiral Codes2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This master thesis is about providing the implementation of synthesis, detection of spiral symbols and estimating the pan/tilt angle and position by using camera calibration. The focus is however on the latter, the estimation of parameters of localization.

    Spiral symbols are used to be able to give an object an identity as well as to locate it. Due to the spiral symbol´s characteristic shape, we can use the generalized structure tensor (GST) algorithm which is particularly efficient to detect different members of the spiral family. Once we detect spirals, we know the position and identity parameters of the spirals within an apriori known geometric configuration (on a sheet of paper). In turn, this information can be used to estimate the 3D-position and orientation of the object on which spirals are attached using a camera calibration method.

     

    This thesis provides an insight into how automatic detection of spirals attached on a sheet of paper, and from this, automatic deduction of position and pose parameters of the sheet, can be achieved by using a network camera. GST algorithm has an advantage of running the processes of detection of spirals efficiently w.r.t detection performance and computational resources because it uses a spiral image model well adapted to spiral spatial frequency characteristic. We report results on how detection is affected by zoom parameters of the network camera, as well as by the GST parameters; such as filter size. After all spirals centers are located and identified w.r.t. their twist/bending parameter, a flexible technique for camera calibration, proposed by Zhengyou Zhang implemented in Matlab within the present study, is performed. The performance of the position and pose estimation in 3D is reported.

    The main conclusion is, we have reasonable surface angle estimations for images which were taken by a WLAN network camera in different conditions such as different illumination and different distances. 

  • 88.
    Al-egli, Muntaher
    et al.
    Linköpings universitet, Institutionen för datavetenskap.
    Zeidan Nasser, Adham
    Linköpings universitet, Institutionen för datavetenskap.
    Identifiering av anomalier i COSMIC genom analys av loggar2015Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Loggar är en viktig del av alla system, det ger en inblick i vad som sker. Att analysera loggar och extrahera väsentlig information är en av de största trenderna nu inom IT-branchen. Informationen i loggar är värdefulla resurser som kan användas för att upptäcka anomalier och hantera dessa innan det drabbar användaren.

    I detta examensarbete dyker vi in i grunderna för informationssökning och analysera undantagsutskrifter i loggar från COSMIC för att undersöka om det är möjligt att upptäcka anomalier med hjälp av retrospektivdata. Detta examensarbete ger även en inblick i möjligheten att visualisera data från loggar och erbjuda en kraftfull sökmotor. Därför kommer vi att fördjupa oss i de tre välkända program som adresserar frågorna i centraliserad loggning: Elasticsearch, Logstash och Kibana.

    Sammanfattningsvis visar resultatet att det är möjligt att upptäckta anomalier genom att tillämpa statistiska metoder både på retrospektiv- och realtidsdata.

  • 89.
    Aleksakhin, Vladyslav
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Visualization of gene ontology and cluster analysis results2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The purpose of the thesis is to develop a new visualization method for Gene Ontologiesand hierarchical clustering. These are both important tools in biology andmedicine to study high-throughput data such as transcriptomics and metabolomicsdata. Enrichment of ontology terms in the data is used to identify statistically overrepresentedontology terms, that give insight into relevant biological processes orfunctional modules. Hierarchical clustering is a standard method to analyze andvisualize data to nd relatively homogeneous clusters of experimental data points.Both methods support the analysis of the same data set, but are usually consideredindependently. However, often a combined view such as: visualizing a large data setin the context of an ontology under consideration of a clustering of the data.The result of the current work is a user-friendly program that combines twodi erent views for analysing Gene Ontology and Cluster simultaneously. To makeexplorations of such a big data possible we developed new visualization approach.

  • 90.
    Alerby, Theodor
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Cisco Application Centric Infrastructure: D0032D Examensarbete2016Självständigt arbete på grundnivå (högskoleexamen), 5 poäng / 7,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In a world were data / network infrastructures grows by the day, it is not unfamiliar for tools that streamline the work and provides a great scalability is put into production. In this paper I will describe one of these solutions called ACI (Application Centric The infrastructure). Cisco ACI is possible thanks to a combination of different components that interact with dedicated hard / software, in this paper the fundamentals behind these different components will be described what ACI is and how it works. This will be compared to a traditional data solution implemented by myself. For four weeks, I worked at Axians IT in Solna researching automation / streamlining solutions and what pros / cons they have on real IT companies and data centers. During these four weeks I worked parallel to my research conducting an implementation of a data solution to the company EEHunddagis to give them their own production environment and then compare my hand configured solution with an automation solution and what pros / cons they both bring with them Automation is something that has risen up in the later years and is still on the rise. I will therefore in this paper explain why these types of solutions are necessary and who could use them in their own network environment. 

  • 91.
    Alexandru, Iordan
    et al.
    Norwegian University of Science and Technology Trondheim.
    Podobas, Artur
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikation: Infrastruktur och tjänster, Programvaru- och datorsystem, SCS.
    Natvig, Lasse
    Norwegian University of Science and Technology Trondheim.
    Brorsson, Mats
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikation: Infrastruktur och tjänster, Programvaru- och datorsystem, SCS.
    Investigating the Potential of Energy-savings Using a Fine-grained Task Based Programming Model on Multi-cores2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we study the relation between energy-efficiencyand parallel executions when implemented with a fine-grained task-centricprogramming model. Using a simulation framework comprised of an ar-chitectural simulator and a power and area estimation tool, we haveinvestigated the potential energy-savings when employing parallelism onmulti-cores system. In our experiments with 2 - 8 multi-cores systems,we employed frequency and voltage scaling in order to keep the relativeperformance of the systems constant and measured the energy-efficiencyusing the Energy-delay-product. Also, we compared the energy consump-tion of the parallel execution against the serial one. Our results showthat through judicious choice of load balancing parameters, significantimprovements of around 200 % in energy consumption can be acheived.

  • 92.
    Alfredsson, Stefan
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
    A Case Study of Recent Mifare Classic Field Deployments From an (In-)Security Perspective2013Ingår i: Proceedings of the 21st International Conference on Software, Telecommunications and Computer Networks (SoftCOM 2013), Split, Croatia: FESB, University of Split , 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mifare Classic is a very popular near-field communication technology that provides a shared-key, access-controlled, storage. Although the authentication protocol of Mifare Classic is compromised since half a decade, systems are still being deployed based on this technology, e.g. for access control systems and for public transport ticketing. By using commodity hardware, such as NFC enabled smartphones, by passing the security measures in some cases only require the installation and operation of a smartphone app. To this end, we present case studies of a number of recent Mifare Classic systems deployed during the last year, to serve as an illustration of practical security problems and to raise awareness thereof among NFC technology buyers and system implementors.

  • 93.
    Alfredsson, Stefan
    Karlstads universitet, Institutionen för informationsteknologi.
    TCP in Wireless Networks: Challenges, Optimizations and Evaluations2005Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis presents research on transport layer behavior in wireless networks. As the Internet is expanding its reach to include mobile devices, it has become apparent that some of the original design assumptions for the dominant transport protocol, TCP, are approaching their limits. A key feature of TCP is the congestion control algorithm, constructed with the assumption that packet loss is normally very low, and that packet loss therefore is a sign of network congestion. This holds true for wired networks, but for mobile wireless networks non-congestion related packet loss may appear. The varying signal power inherent with mobility and handover between base-stations are two example causes of such packet loss. This thesis provides an overview of the challenges for TCP in wireless networks together with a compilation of a number of suggested TCP optimizations for these environments. A TCP modification called TCP-L is proposed. It allows an application to increase its performance, in environments where residual bit errors normally give a degraded throughput, by making a reliability tradeoff. The performance of TCP-L is experimentally evaluated with an implementation in the Linux kernel. The transport layer performance in a 4G scenario is also experimentally investigated, focusing on the impact of the link layer design and its parameterization. Further, for emulation-based protocol evaluations, controlled packet loss and bit error generation is shown to be an important aspect.

  • 94.
    Alfredsson, Stefan
    et al.
    Karlstads universitet, Institutionen för informationsteknologi.
    Brunstrom, Anna
    Karlstads universitet, Institutionen för informationsteknologi.
    Bit Error Tolerant Multimedia Transport2004Ingår i: Perspectives on Multimedia: Communication, Media and Information Technology, Chichester: John Wiley & Sons, 2004, 175-191 s.Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 95.
    Alfredsson, Stefan
    et al.
    Karlstads universitet, Institutionen för informationsteknologi.
    Brunstrom, Anna
    Karlstads universitet, Institutionen för informationsteknologi.
    TCP-L: Allowing Bit Errors in Wireless TCP2003Ingår i: Proceedings of the 12th IST Summit on Mobile and Wireless Communications: Enabling a Pervasive Wireless World / [ed] Atílio Gameiro, Institute for Operations Research and the Management Sciences (INFORMS), 2003, 149-154 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a technique to improve the performance of TCP and the utilization of wireless networks.Wireless links exhibit high rates of bit errors, compared to communication over wireline or fiber. Since TCP cannotseparate packet losses due to bit errors versus congestion,all losses are treated as signs of congestion and congestionavoidance is initiated. This paper explores the possibility of accepting TCP packets with an erroneous checksum, toimprove network performance for those applications that can tolerate bit errors. Since errors may be in the TCP header aswell as the payload, the possibility of recovering the headeris discussed. An algorithm for this recovery is also presented.Experiments with an implementation have been performed,which show that large improvements in throughput can beachieved, depending on link and error characteristics.

  • 96.
    Alfredsson, Stefan
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Institutionen för informationsteknologi.
    Brunstrom, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Institutionen för informationsteknologi.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    A 4G Link Level Emulator for Transport Protocol Evaluation2004Ingår i: Proceedings of The Second Swedish National Computer Networking Workshop (SNCNW), 2004, 19-23 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a wireless link and networkemulator, based upon the "Wireless IP" 4G system proposalfrom Uppsala University and partners. In wireless fading down-links (base to terminals) link-level frames are scheduled andthe transmission is adapted on a fast time scale. With fastlink adaptation and fast link level retransmission, the fading properties of wireless links can to a large extent be counteractedat the physical and link layers. A purpose of the emulatoris to investigate the resulting interaction with transport layer protocols. The emulator is built on Internet technologies, andis installed as a gateway between communicating hosts. The paper gives an overview of the emulator design, and presentspreliminary experiments with three different TCP variants. The results illustrate the functionality of the emulator by showing theeffect of changing link layer parameters on the different TCP variants.

  • 97.
    Alfredsson, Stefan
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Brunstrom, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    Cross-layer analysis of TCP performance in a 4G system2007Ingår i: Proceedings of the 15th International Conference on Software, Telecommunications and Computer Networks, IEEE Computer Society, 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents results from an experimental study of TCP in a wireless 4G evaluation system. Test-bed results on transport layer performance are presented and analyzed in relation to several link layer aspects. The aspects investigated are the impact of channel prediction errors, channel scheduling, delay, and adaptive modulation switch level, on TCP performance. The paper contributes a cross-layer analysis of the interaction between symbol modulation levels, different scheduling strategies, channel prediction errors and the resulting frame retransmissions effect on TCP. The paper also shows that highly persistent ARQ with fast link retransmissions do not interact negatively with the TCP retransmission timer even for short round trip delays.

  • 98.
    Alfredsson, Stefan
    et al.
    Karlstads universitet, Institutionen för informationsteknologi. Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Brunstrom, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Institutionen för informationsteknologi.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    Emulation and Validation of a 4G System Proposal2005Ingår i: Proceedings of RadioVetenskap och Kommunikation 2005: Volume II, 2005, 357-362 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a wireless link and network emulator,along with experiments and validation against the "Wireless IP" 4G system proposal from Uppsala University and partners. In wireless fading downlinks (base to terminals) link-level frames are scheduled and the transmission is adapted on a fast time scale. With fast link adaptation and fast link level retransmission, the fading properties of wireless links can to a large extent be counteracted at thephysical and link layers. The emulator has been used to experimentally investigate the resulting interaction between the transport layer and the link layer. The paper gives an overview of the emulator design, and presents experimental results with three different TCP variants in combination with various link layer characteristics.

  • 99.
    Alfredsson, Stefan
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Brunstrom, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    Impact of 4G Wireless Link Configurations on VoIP Network Performance2008Ingår i: Proceedings of the 2008 IEEE International Symposium on Wireless Communication Systems, IEEE Communications Society, 2008, 708-712 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The performance of applications in wireless networks is partly dependent upon the link configuration. Link characteristics varies with frame retransmission persistency, link frame retransmission delay, adaptive modulation strategies, coding, and more. The link configuration and channel conditions can lead to packet loss, delay and delay variations, which impact different applications in different ways. A bulk transfer application may tolerate delays to a large extent, while packet loss is undesirable. On the other hand, real-time interactive applications are sensitive to delay and delay variations, but may tolerate packet loss to a certain extent. This paper contributes a study of the effect of link frame retransmission persistency and delay on packet loss and latency for real-time interactive applications. The results indicate that a reliable retransmission mechanism with fast link retransmissions in the range of 2-8 ms is sufficient to provide an upper delay bound of 50 ms over the wireless link, which is well within the delay budget of voice over IP applications.

  • 100.
    Alfredsson, Stefan
    et al.
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Brunstrom, Anna
    Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap.
    Mikael, Sternad
    Signaler och System, Uppsala universitet.
    Transport Protocol Performance over 4G Links: Emulation Methodology and Results2006Ingår i: Proceedings of the International Symposium on Wireless Communication Systems (ISWCS), IEEE Computer Society, 2006, 327-332 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a wireless link and network emulator for the "Wireless IP" 4G system proposal from Uppsala University and partners. In wireless fading downlinks (base to terminals) link-level frames are scheduled and the transmission is adapted on a fast time scale. With fast link adaptation and fast link level retransmission, the fading properties of wireless links can to a large extent be counteracted at the physical and link layers. The emulator has been used to experimentally investigate the resulting interaction between the transport layer and the physical/link layer in such a downlink. The paper introduces the Wireless IP system, describes the emulator design and implementation, and presents experimental results with TCP in combination with various physical/link layer parameters. The impact of link layer ARQ persistency, adaptive modulation, prediction errors and simple scheduling are all considered.

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