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  • 301.
    Shrestha, Amendra
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Kaati, Lisa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. FOI, Stockholm, Sweden..
    Cohen, Katie
    FOI, Stockholm, Sweden..
    A Machine Learning Approach Towards Detecting Extreme Adopters in Digital Communities2017Inngår i: 2017 28th International Workshop on Database and Expert Systems Applications (DEXA) / [ed] Tjoa, AM Wagner, RR, IEEE, 2017, s. 1-5Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In this study we try to identify extreme adopters on a discussion forum using machine learning. An extreme adopter is a user that has adopted a high level of a community-specific jargon and therefore can be seen as a user that has a high degree of identification with the community. The dataset that we consider consists of a Swedish xenophobic discussion forum where we use a machine learning approach to identify extreme adopters using a number of linguistic features that are independent on the dataset and the community. The results indicates that it is possible to separate these extreme adopters from the rest of the discussants on the discussion forum with more than 80% accuracy. Since the linguistic features that we use are highly domain independent, the results indicates that there is a possibility to use this kind of techniques to identify extreme adopters within other communities as well.

  • 302.
    Sigurgeirsson, Daniel
    et al.
    Reykjavik Univ, Sch Comp Sci, Reykjavik, Iceland.
    Lárusdóttir, Marta
    Reykjavik Univ, Sch Comp Sci, Reykjavik, Iceland.
    Hamdaga, Mohammad
    Reykjavik Univ, Sch Comp Sci, Reykjavik, Iceland.
    Daniels, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Jónsson, Björn
    Reykjavik Univ, Sch Comp Sci, Reykjavik, Iceland.
    Learning Outcome Outcomes: An Evaluation of Quality2018Inngår i: Proc. 48th ASEE/IEEE Frontiers in Education Conference, Piscataway, NJ: IEEE Press, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Learning outcomes are a standard specification of knowledge, skills and capabilities that a student is expected to acquire by attending a course or a degree program. While, in theory, the process of evaluating learning outcomes appears to be trivial, in practice it is a complicated and daunting process. In this study, we evaluate how learning outcomes can be effectively applied. The work focuses on the quality of both the specification of the learning outcomes and the assessment of whether these outcomes are reached. We discuss different abstraction levels for learning outcomes and the issue of alignment between high-level and low-level learning outcomes. We also address the criteria for assessing whether a student is meeting a learning outcome.

    Our work is focused on project-oriented courses, where assessing learning outcomes is seen as particularly challenging. In particular, we draw on an empirical study focused on systematically collecting key performance indicators of the progress towards achieving learning outcomes. The data gathering was done during the course through in-class questionnaires and individual diary notes, as a complementary process to the traditional observations made by the teacher running the course. This data serves as the basis for understanding how individual students advance towards the stated learning goals. We also conducted a focus group discussion after the course to better understand how to interpret the data collected during the course.

    An important result of our work is forming an understanding and vocabulary regarding learning outcomes and the assessment of how well students meet these learning goals in project-based educational settings. In addition to this, we make the following major contributions:

    • We present a systematic methodology to gauge how well students meet learning outcomes through in-class self-evaluation.
    • We present the results of an empirical study of a process-oriented evaluation of the students' development towards stated learning outcomes.

    We state some lessons learned from this process, that are applicable for designers of project-based courses.

  • 303. Singh, Abhishek
    et al.
    Ekberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Baruah, Sanjoy
    Applying Real-Time Scheduling Theory to the Synchronous Data Flow Model of Computation2017Konferansepaper (Fagfellevurdert)
  • 304. Singh, Abhishek
    et al.
    Ekberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Baruah, Sanjoy
    Uniprocessor scheduling of real-time synchronous dataflow tasks2019Inngår i: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 55, nr 1, s. 1-31Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The synchronous dataflow graph (SDFG) model is widely used today for modeling real-time applications in safety-critical application domains. Schedulability analysis techniques that are well understood within the real-time scheduling community are applied to the analysis of recurrent real-time workloads that are represented using this model. An enhancement to the standard SDFG model is proposed, which supports the specification of a real-time latency constraint between a specified input and a specified output of an SDFG. A polynomial-time algorithm is derived for representing the computational requirement of each such enhanced SDFG task in terms of the notion of the demand bound function (dbf), which is widely used in real-time scheduling theory for characterizing computational requirements of recurrent processes represented by, e.g., the sporadic task model. By so doing, the extensive dbf-centered machinery that has been developed in real-time scheduling theory for the hard-real-time schedulability analysis of systems of recurrent tasks may be applied to the analysis of systems represented using the SDFG model as well. The applicability of this approach is illustrated by applying prior results from real-time scheduling theory to construct an exact preemptive uniprocessor schedulability test for collections of independent recurrent processes that are each represented using the enhanced SDFG model.

  • 305.
    Stigge, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Yi, Wang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Combinatorial abstraction refinement for feasibility analysis of static priorities2015Inngår i: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 51, nr 6, s. 639-674Artikkel i tidsskrift (Fagfellevurdert)
  • 306.
    Stigge, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Yi, Wang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Graph-based models for real-time workload: a survey2015Inngår i: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 51, nr 5, s. 602-636Artikkel i tidsskrift (Fagfellevurdert)
  • 307.
    Sun, Jinghao
    et al.
    Northeastern Univ, Sch Comp Sci & Engn, Shenyang 110004, Liaoning, Peoples R China;Hong Kong Polytech Univ, Dept Comp, Hong Kong, Hong Kong, Peoples R China.
    Guan, Nan
    Hong Kong Polytech Univ, Dept Comp, Hong Kong, Hong Kong, Peoples R China.
    Jiang, Xu
    Hong Kong Polytech Univ, Dept Comp, Hong Kong, Hong Kong, Peoples R China.
    Chang, Shuangshuang
    Northeastern Univ, Sch Comp Sci & Engn, Shenyang 110004, Liaoning, Peoples R China.
    Guo, Zhishan
    Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA;Missouri Univ Sci & Technol, Dept Comp Sci, Rolla, MO 65409 USA.
    Deng, Qingxu
    Northeastern Univ, Sch Comp Sci & Engn, Shenyang 110004, Liaoning, Peoples R China.
    Wang, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Northeastern Univ, Sch Comp Sci & Engn, Shenyang 110004, Liaoning, Peoples R China.
    A Capacity Augmentation Bound for Real-Time Constrained-Deadline Parallel Tasks Under GEDF2018Inngår i: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, ISSN 0278-0070, E-ISSN 1937-4151, Vol. 37, nr 11, s. 2200-2211Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Capacity augmentation bound is a widely used quantitative metric in theoretical studies of schedulability analysis for directed acyclic graph (DAG) parallel real-time tasks, which not only quantifies the suboptimality of the scheduling algorithms, but also serves as a simple linear-time schedulability test. Earlier studies on capacity augmentation bounds of the sporadic DAG task model were either restricted to a single DAG task or a set of tasks with implicit deadlines. In this paper, we consider parallel tasks with constrained deadlines under global earliest deadline first policy. We first show that it is impossible to obtain a constant bound for our problem setting, and derive both lower and upper bounds of the capacity augmentation bound as a function with respect to the maximum ratio of task period to deadline. Our upper bound is at most 1.47 times larger than the optimal one. We conduct experiments to compare the acceptance ratio of our capacity augmentation bound with the existing schedulability test also having linear-time complexity. The results show that our capacity augmentation bound significantly outperforms the existing linear-time schedulability test under different parameter settings.

  • 308. Sun, Jinghao
    et al.
    Guan, Nan
    Wang, Yang
    Deng, Qingxu
    Zeng, Peng
    Yi, Wang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Feasibility of fork-join real-time task graph models: Hardness and algorithms2016Inngår i: ACM Transactions on Embedded Computing Systems, ISSN 1539-9087, E-ISSN 1558-3465, Vol. 15, nr 1, artikkel-id 14Artikkel i tidsskrift (Fagfellevurdert)
  • 309.
    Sun, Jinghao
    et al.
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China.;Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Guan, Nan
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Wang, Yang
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    He, Qingqiang
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Wang, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Real-Time Scheduling and Analysis of OpenMP Task Systems with Tied Tasks2017Inngår i: 2017 IEEE Real-Time Systems Symposium (RTSS), IEEE, 2017, s. 92-103Konferansepaper (Fagfellevurdert)
    Abstract [en]

    OpenMP is a promising framework for developing parallel real-time software on multi-cores. Although similar to the DAG task model, OpenMP task systems are significantly more difficult to analyze due to constraints posed by the OpenMP specification. An important feature in OpenMP is tied tasks, which must execute on the same thread during the whole life cycle. Although tied tasks enjoy benefits in simplicity and efficiency, it was considered to be not suitable to real-time systems due to its complex behavior. In this paper, we study the real-time scheduling and analysis of OpenMP task systems with tied tasks. First, we show that under the existing scheduling algorithms in OpenMP, tied tasks indeed may lead to extremely bad timing behaviors where the parallel workload is sequentially executed completely. To solve this problem, we proposed a new scheduling algorithm and developed two response time bounds for it, with different trade-off between simplicity and analysis precision. Experiments with both randomly generated OpenMP task systems and realistic OpenMP programs show that the response time bounds obtained by our approach for tied task systems are very close to that of untied tasks.

  • 310.
    Svensson, Maria
    et al.
    Göteborgs universitet.
    Ingerman, Åke
    Göteborgs universitet.
    Berglund, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Teaching and learning system thinking in technology2015Inngår i: Plurality and Complementarity of Approaches in Design and Technology Education / [ed] Chatoney, Marjolaine, Marseille: Presses Universitaires de Provence , 2015, s. 404-409Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Complex technological systems have emerged during the last decade as an important strand in technology teaching in several national curricula for compulsory school. However, even though understanding the systemic aspects and connected nature of contemporary society, it remains unclear what such understanding entails in detail, and even more unclear what may constitute good teaching. We present the results from a teaching-learning design project on the topic of large societal and complex technological systems, which are seen as constituted of transformation and transport, acting on matter, energy and information. The main results are a suggested and evaluated plan of teaching developed in collaboration with a team of technology teachers, as well as descriptions of how pupils’ system thinking is constituted in terms of four basic aspects: Resource and intention of the system; System component constitution; Process and transformation in components and system; Network character. In total, a teaching plan spanning four lessons was realised in four different classrooms, with classes’ sizes ranging 15 to 25 pupils in the ages 14 and 15. The teaching design progresses through focusing specific parts of various systems, for example the transformation of polluted water to clean water in a water purification plant as part of the water supply system. There is an emphasis on the function of the part in relation to the system on the one hand, and on how the part is and can be realised technically, taking care to relate the latter to what is taken up in other curricular strands of technology. The last part focuses the examination of technological systems as constituted by interacting and meaningful parts, where their network nature may emerge.

  • 311.
    Tang, Yue
    et al.
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Guan, Nan
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Liu, Weichen
    Nanyang Technol Univ, Singapore, Singapore..
    Phan, Linh Thi Xuan
    Yi, Wang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Revisiting GPC and AND Connector in Real-Time Calculus2017Inngår i: 2017 IEEE Real-Time Systems Symposium (RTSS), IEEE, 2017, s. 255-265Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Real-Time Calculus (RTC) is a powerful framework for modeling and worst-case performance analysis of networked systems. GPC and AND are two fundamental components in RTC, which model priority-based resource arbitration and synchronization operations, respectively. In this paper, we revisit GPC and AND. For GPC, we develop tighter output arrival curves to more precisely characterize the output event streams. For AND, we first identify a problem in the existing analysis method that may lead to negative values in the output curves, and present corrections to the problem. Then we generalize AND to synchronize more than two input event streams. We implement our new theoretical results and conduct experiments to evaluate their performance. Experiment results show significant improvement of our new methods in analysis precision and efficiency.

  • 312.
    Thota, Neena
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Connectivism and the use of technology/media in collaborative teaching and learning2015Inngår i: From the Confucian Way to Collaborative Knowledge Co-Construction / [ed] van Schalkwyk, Gertina J.; D'Amato, Rik Carl, Hoboken, NJ: John Wiley & Sons, 2015, s. 81-96Kapittel i bok, del av antologi (Fagfellevurdert)
  • 313.
    Thota, Neena
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Berglund, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    A structured approach to master thesis writing2015Inngår i: Conference for University Pedagogical Development, Uppsala, Sweden: Uppsala University, 2015Konferansepaper (Annet vitenskapelig)
  • 314.
    Thota, Neena
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Berglund, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Integrating international students into CS programs2015Inngår i: Proc. 1st Al Baha University and Uppsala University Symposium on Quality in Computing Education, 2015, s. 6-8Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In recent years there has been a rapid increase in the intake of international students at universities. Integrating foreign students into the disciplinary and social culture prevalent at the university is a challenging task. In this paper, first, we summarize the findings of three of our studies on the experiences of Chinese students studying computer science at the Department of Information Technology, Uppsala University, Sweden. Then, based on our findings we make recommendations on how to integrate international students into academic life at Computer Science departments. We focus on the program and course levels, and also at the level of individual students in their new social and cultural environment.

  • 315.
    Thota, Neena
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Berglund, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Learning Computer Science: Dimensions of variation within what Chinese students learn2016Inngår i: ACM Transactions on Computing Education, ISSN 1946-6226, E-ISSN 1946-6226, Vol. 16, nr 3, artikkel-id 10Artikkel i tidsskrift (Fagfellevurdert)
  • 316.
    Thota, Neena
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Estadieu, Gerald
    Ferrao, Antonio
    Wong, Kai Meng
    Engaging school students with tangible devices: Pilot project with .NET gadgeteer2015Inngår i: Proc. 3rd International Conference on Learning and Teaching in Computing and Engineering, Los Alamitos, CA: IEEE Computer Society, 2015, s. 112-119Konferansepaper (Fagfellevurdert)
  • 317.
    Thota, Neena
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. University of Saint Joseph, Macau, China.
    Negreiros, João G. M.
    Introducing Educational Technologies to Teachers: Experience Report2015Inngår i: Journal of University Teaching and Learning Practice, ISSN 1449-9789, E-ISSN 1449-9789, Vol. 12, nr 1, s. 5:1-13Artikkel i tidsskrift (Fagfellevurdert)
  • 318. Tian, Ye
    et al.
    Li, Xiong
    Sangaiah, Arun Kumar
    Ngai, Edith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Song, Zheng
    Zhang, Lanshan
    Wang, Wendong
    Privacy-preserving scheme in social participatory sensing based on Secure Multi-party Cooperation2018Inngår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 119, s. 167-178Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Social participant sensing has been widely used to collect location related sensory data for various applications. In order to improve the Quality of Information (QoI) of the collected data with constrained budget, the application server needs to coordinate participants with different data collection capabilities and various incentive requirements. However, existing participant coordination methods either require participants to reveal their trajectories to the server which causes privacy leakage, or tradeoff the location accuracy of participants for privacy, thereby leading to lower QoI. In this paper, we propose a privacy-preserving scheme, which allows application server to provide quasi-optimal QoI for social sensing tasks without knowing participants’ trajectories and identity. More specifically, we first suggest a Secure Multi-party Cooperation (SMC) based approach to evaluate participant’s contribution in terms of QoI without disclosing each individual’s trajectory. Second, a fuzzy decision based approach which aims to finely balance data utility gain, incentive budget and inferable privacy protection ability is adopted to coordinate participant in an incremental way. Third, sensory data and incentive are encrypted and then transferred along with participant-chain in perturbed way to protect user privacy throughout the data uploading and incentive distribution procedure. Simulation results show that our proposed method can efficiently select appropriate participants to achieve better QoI than other methods, and can protect each participant’s privacy effectively.

  • 319. Tian, Ye
    et al.
    Wang, Wendong
    Wu, Jie
    Kou, Qinli
    Song, Zheng
    Ngai, Edith C.-H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Privacy-preserving social tie discovery based on cloaked human trajectories2017Inngår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 66, nr 2, s. 1619-1630Artikkel i tidsskrift (Fagfellevurdert)
  • 320.
    Tran, Kim-Anh
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Jimborean, Alexandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Carlson, Trevor E.
    National University of Singapore, Singapore.
    Koukos, Konstantinos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Själander, Magnus
    NTNU, Norway.
    Kaxiras, Stefanos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    SWOOP: software-hardware co-design for non-speculative, execute-ahead, in-order cores2018Inngår i: Proceedings of the 39th ACM SIGPLAN Conference on Programming Language Design and Implementation, Association for Computing Machinery (ACM), 2018, s. 328-343Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Increasing demands for energy efficiency constrain emerging hardware. These new hardware trends challenge the established assumptions in code generation and force us to rethink existing software optimization techniques. We propose a cross-layer redesign of the way compilers and the underlying microarchitecture are built and interact, to achieve both performance and high energy efficiency.

    In this paper, we address one of the main performance bottlenecks — last-level cache misses — through a software-hardware co-design. Our approach is able to hide memory latency and attain increased memory and instruction level parallelism by orchestrating a non-speculative, execute-ahead paradigm in software (SWOOP). While out-of-order (OoO) architectures attempt to hide memory latency by dynamically reordering instructions, they do so through expensive, power-hungry, speculative mechanisms.We aim to shift this complexity into software, and we build upon compilation techniques inherited from VLIW, software pipelining, modulo scheduling, decoupled access-execution, and software prefetching. In contrast to previous approaches we do not rely on either software or hardware speculation that can be detrimental to efficiency. Our SWOOP compiler is enhanced with lightweight architectural support, thus being able to transform applications that include highly complex control-flow and indirect memory accesses.

  • 321.
    Tshering, Phurpa
    et al.
    Royal University of Bhutan, Bhutan.
    Lhamo, Dekar
    Royal University of Bhutan, Bhutan.
    Yu, Lu
    Tongji University, China.
    Berglund, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    How do first year students learn C programming in Bhutan?2017Inngår i: Proc. 5th International Conference on Learning and Teaching in Computing and Engineering, IEEE Computer Society, 2017, s. 25-29Konferansepaper (Fagfellevurdert)
  • 322.
    Tsiftes, Nicolas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datorteknik. SICS.
    Storage-Centric System Architectures for Networked, Resource-Constrained Devices2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The emergence of the Internet of Things (IoT) has increased the demand for networked, resource-constrained devices tremendously. Many of the devices used for IoT applications are designed to be resource-constrained, as they typically must be small, inexpensive, and powered by batteries. In this dissertation, we consider a number of challenges pertaining to these constraints: system support for energy efficiency; flash-based storage systems; programming, testing, and debugging; and safe and secure application execution. The contributions of this dissertation are made through five research papers addressing these challenges.

    Firstly, to enhance the system support for energy-efficient storage in resource-constrained devices, we present the design, implementation, and evaluation of the Coffee file system and the Antelope DBMS. Coffee provides a sequential write throughput that is over 92% of the attainable flash driver throughput, and has a constant memory footprint for open files. Antelope is the first full-fledged relational DBMS for sensor networks, and it provides two novel indexing algorithms to enable fast and energy-efficient database queries.

    Secondly, we contribute a framework that extends the functionality and increases the performance of sensornet checkpointing, a debugging and testing technique. Furthermore, we evaluate how different data compression algorithms can be used to decrease the energy consumption and data dissemination time when reprogramming sensor networks.

    Lastly, we present Velox, a virtual machine for IoT applications. Velox can enforce application-specific resource policies. Through its policy framework and its support for high-level programming languages, Velox helps to secure IoT applications. Our experiments show that Velox monitors applications' resource usage and enforces policies with an energy overhead below 3%.

    The experimental systems research conducted in this dissertation has had a substantial impact both in the academic community and the open-source software community. Several of the produced software systems and components are included in Contiki, one of the premier open-source operating systems for the IoT and sensor networks, and they are being used both in research projects and commercial products.

    Delarbeid
    1. Efficient Sensor Network Reprogramming through Compression of Executable Modules
    Åpne denne publikasjonen i ny fane eller vindu >>Efficient Sensor Network Reprogramming through Compression of Executable Modules
    2008 (engelsk)Inngår i: Proceedings of Fifth Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON 2008): June 16-20, 2008, San Francisco, California, USA. 2008, 2008Konferansepaper, Publicerat paper (Fagfellevurdert)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-142776 (URN)
    Konferanse
    Fifth Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON 2008): June 16-20, 2008, San Francisco, California, USA. 2008
    Prosjekter
    wisenet
    Tilgjengelig fra: 2011-01-17 Laget: 2011-01-17 Sist oppdatert: 2018-01-12
    2. Enabling Large- Scale Storage in Sensor Networks with the Coffee File System
    Åpne denne publikasjonen i ny fane eller vindu >>Enabling Large- Scale Storage in Sensor Networks with the Coffee File System
    2009 (engelsk)Inngår i: Proceedings of the 8th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN 2009), San Francisco, USA, April 2009, 2009Konferansepaper, Publicerat paper (Fagfellevurdert)
    Identifikatorer
    urn:nbn:se:uu:diva-142686 (URN)
    Konferanse
    8th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN 2009), San Francisco, USA, April 2009
    Prosjekter
    wisenet
    Tilgjengelig fra: 2011-01-14 Laget: 2011-01-14 Sist oppdatert: 2016-02-12
    3. A Database in Every Sensor
    Åpne denne publikasjonen i ny fane eller vindu >>A Database in Every Sensor
    2011 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Emneord
    Antelope, database, energy-efficiency, sensor network
    HSV kategori
    Forskningsprogram
    Datavetenskap med inriktning mot databasteknik
    Identifikatorer
    urn:nbn:se:uu:diva-267634 (URN)
    Konferanse
    The 9th ACM Conference on Embedded Networked Sensor Systems (SenSys 2011)
    Forskningsfinansiär
    EU, FP7, Seventh Framework Programme, FP7-ICT-224282EU, FP7, Seventh Framework Programme, FP7-2007-2-224053Swedish Foundation for Strategic Research
    Tilgjengelig fra: 2015-11-25 Laget: 2015-11-25 Sist oppdatert: 2018-01-10
    4. Efficient and Flexible Sensornet Checkpointing
    Åpne denne publikasjonen i ny fane eller vindu >>Efficient and Flexible Sensornet Checkpointing
    2014 (engelsk)Inngår i: Wireless Sensor Networks, volume 8354, 2014, s. -65Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Developing sensornet software is difficult partly because ofthe limited visibility of the system state of deployed nodes. Sensor-net checkpointing is a method that allows developers to save and restore full system state of nodes. We present four extensions to sensornetcheckpointing—compression, binary diffs, selective checkpointing, and checkpoint inspection—that reduce the time required for checkpointing operations considerably, and improve the granularity at which system state can be examined and manipulated down to the variable level. We show through an experimental evaluation that the checkpoint sizes can be reduced by 70%-93%, and the time can be reduced by at least 50% because of these improvements. The reduced time and increased granularity benefits multiple checkpointing use cases, including automated testing, network visualization, and software debugging.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-211145 (URN)0.1007/978-3-319-04651-8_4 (DOI)000340395900004 ()978-3-319-04650-1 (ISBN)978-3-319-04651-8 (ISBN)
    Konferanse
    EWSN 2014: The European Conference on Wireless Sensor Networks; 17-19 February 2014; University of Oxford; Oxford, UK
    Prosjekter
    ProFuN
    Tilgjengelig fra: 2013-11-20 Laget: 2013-11-20 Sist oppdatert: 2016-02-12bibliografisk kontrollert
    5. Velox: A Virtual Machine for IoT Software Security and Resource Protection
    Åpne denne publikasjonen i ny fane eller vindu >>Velox: A Virtual Machine for IoT Software Security and Resource Protection
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    HSV kategori
    Forskningsprogram
    Datavetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-268870 (URN)
    Forskningsfinansiär
    VINNOVAKnowledge Foundation
    Tilgjengelig fra: 2015-12-10 Laget: 2015-12-10 Sist oppdatert: 2018-01-10
  • 323.
    Tsiftes, Nicolas
    et al.
    RISE SICS, Box 1263, SE-16429 Kista, Sweden.
    Voigt, Thiemo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation. RISE SICS, Box 1263, SE-16429 Kista, Sweden.
    Velox VM: A safe execution environment for resource-constrained IoT applications2018Inngår i: Journal of Network and Computer Applications, ISSN 1084-8045, E-ISSN 1095-8592, Vol. 118, s. 61-73Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present Velox, a virtual machine architecture that provides a safe execution environment for applications in resource-constrained IoT devices. Our goal with this architecture is to support developers in writing and deploying safe IoT applications, in a manner similar to smartphones with application stores. To this end, we provide a resource and security policy framework that enables fine-grained control of the execution environment of IoT applications. This framework allows device owners to configure, e.g., the amount of bandwidth, energy, and memory that each IoT application can use. Velox's features also include support for high-level programming languages, a compact bytecode format, and preemptive multi-threading. In the context of IoT devices, there are typically severe energy, memory, and processing constraints that make the design and implementation of a virtual machine with such features challenging. We elaborate on how Velox is implemented in a resource-efficient manner, and describe our port of Velox to the Contiki OS. Our experimental evaluation shows that we can control the resource usage of applications with a low overhead. We further show that, for typical I/O-driven IoT applications, the CPU and energy overhead of executing Velox bytecode is as low as 1-5% compared to corresponding applications compiled to machine code. Lastly, we demonstrate how application policies can be used to mitigate the possibility of exploiting vulnerable applications.

  • 324.
    Tsiftes, Nicolas
    et al.
    RISE SICS.
    Voigt, Thiemo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Velox VM: A safe execution environment for resource-constrained IoT applications2018Inngår i: Journal of Network and Computer Applications, ISSN 1084-8045, E-ISSN 1095-8592, Vol. 18, s. 61-73Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present Velox, a virtual machine architecture that provides a safe execution environment for applications in resource-constrained IoT devices. Our goal with this architecture is to support developers in writing and deploying safe IoT applications, in a manner similar to smartphones with application stores. To this end, we provide a resource and security policy framework that enables fine-grained control of the execution environment of IoT applications. This framework allows device owners to configure, e.g., the amount of bandwidth, energy, and memory that each IoT application can use. Velox's features also include support for high-level programming languages, a compact bytecode format, and preemptive multi-threading.

    In the context of IoT devices, there are typically severe energy, memory, and processing constraints that make the design and implementation of a virtual machine with such features challenging. We elaborate on how Velox is implemented in a resource-efficient manner, and describe our port of Velox to the Contiki OS. Our experimental evaluation shows that we can control the resource usage of applications with a low overhead. We further show that, for typical I/O-driven IoT applications, the CPU and energy overhead of executing Velox bytecode is as low as 1–5% compared to corresponding applications compiled to machine code. Lastly, we demonstrate how application policies can be used to mitigate the possibility of exploiting vulnerable applications.

  • 325.
    Tu, Wei
    et al.
    Wuhan Univ, Coll Comp, Wuhan, Peoples R China..
    Wei, Lei
    Hunan Univ, Coll Comp Sci & Elect Engn, Changsha, Hunan, Peoples R China..
    Hu, Wenyan
    Carnegie Mellon Univ, Sch Comp Sci, Pittsburgh, PA 15213 USA..
    Sheng, Zhengguo
    Univ Sussex, Dept Engn & Design, Brighton, E Sussex, England..
    Nicanfar, Hasen
    Univ British Columbia, Dept Elect & Comp Engn, Vancouver, BC, Canada..
    Hu, Xiping
    Univ British Columbia, Dept Elect & Comp Engn, Vancouver, BC, Canada..
    Ngai, Edith C.-H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Leung, Victor C. M.
    Univ British Columbia, Dept Elect & Comp Engn, Vancouver, BC, Canada..
    A Survey on Mobile Sensing Based Mood-Fatigue Detection for Drivers2016Inngår i: SMART CITY 360 / [ed] LeonGarcia, A Lenort, R Holman, D Stas, D Krutilova, V Wicher, P Caganova, D Spirkova, D Golej, J Nguyen, K, SPRINGER INT PUBLISHING AG , 2016, s. 3-15Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The rapid development of the Internet of Things (IoT) has provided innovative solutions to reduce traffic accidents caused by fatigue driving. When drivers are in bad mood or tired, their vigilance level decreases, which may prolong the reaction time to emergency situation and lead to serious accidents. With the help of mobile sensing and mood-fatigue detection, drivers' moodfatigue status can be detected while driving, and then appropriate measures can be taken to eliminate the fatigue or negative mood to increase the level of vigilance. This paper presents the basic concepts and current solutions of moodfatigue detection and some common solutions like mobile sensing and cloud computing techniques. After that, we introduce some emerging platforms which designed to promote safe driving. Finally, we summarize the major challenges in mood-fatigue detection of drivers, and outline the future research directions.

  • 326.
    Ulander, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Software Architectural Metrics for the Scania Internet of Things Platform: From a Microservice Perspectiv2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    There are limited tools to evaluate a microservice architecture and no common definition of how the architecture should be designed. Moreover, developing systems with microservices introduces additional complexity to the software architecture. That, together with the fact the systems are becoming more complex has led to a desire for architecture evaluation methods.

    In this thesis a set of quality attributes measured by structural metrics are used to evaluate Scania's IoT Offboard platform. By implementing a metrics evaluation program the quality of the software architecture can be improved. Also, metrics can assist developers and architects while they are becoming more efficient since they better understand how performance is measured, i.e. which quality attributes are the most important and how these are measured.

    For Scania's IoT Offboard platform the studied quality attributes are listed in decreasing importance: flexibility, reusability and understandability. All the microservices are loosely coupled in the platform, which results in a loosely coupled architecture. This indicates a flexible, reusable and understandable system, in terms of coupling. Furthermore, the architecture is decentralized, i.e. the system is unflexible and difficult to change. The other metrics were lacking a reference scale, hence they will act as a point of reference for future measurements as the architecture evolves.

    To improve the flexibility, reusability and understandability of the architecture the large microservices should be divided into several smaller microservices. Also aggregators should be utilized more to make the system more flexible.

  • 327.
    Van den Steen, Sam
    et al.
    Univ Ghent, Dept Elect & Informat Syst, B-9000 Ghent, Belgium..
    De Pestel, Sander
    Univ Ghent, Dept Elect & Informat Syst, B-9000 Ghent, Belgium..
    Mechri, Moncef
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Eyerman, Stijn
    Univ Ghent, Dept Elect & Informat Syst, B-9000 Ghent, Belgium..
    Carlson, Trevor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Black-Schaffer, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Hagersten, Erik
    Eeckhout, Lieven
    Univ Ghent, Dept Elect & Informat Syst, B-9000 Ghent, Belgium..
    Micro-Architecture Independent Analytical Processor Performance and Power Modeling2015Inngår i: 2015 IEEE International Symposium on Performance Analysis and Software (ISPASS), 2015, s. 32-41Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Optimizing processors for specific application(s) can substantially improve energy-efficiency. With the end of Dennard scaling, and the corresponding reduction in energy-efficiency gains from technology scaling, such approaches may become increasingly important. However, designing application-specific processors require fast design space exploration tools to optimize for the targeted application(s). Analytical models can be a good fit for such design space exploration as they provide fast performance estimations and insight into the interaction between an application's characteristics and the micro-architecture of a processor. Unfortunately, current analytical models require some micro-architecture dependent inputs, such as cache miss rates, branch miss rates and memory-level parallelism. This requires profiling the applications for each cache and branch predictor configuration, which is far more time-consuming than evaluating the actual performance models. In this work we present a micro-architecture independent profiler and associated analytical models that allow us to produce performance and power estimates across a large design space almost instantaneously. We show that using a micro-architecture independent profile leads to a speedup of 25x for our evaluated design space, compared to an analytical model that uses micro-architecture dependent profiles. Over a large design space, the model has a 13% error for performance and a 7% error for power, compared to cycle-level simulation. The model is able to accurately determine the optimal processor configuration for different applications under power or performance constraints, and it can provide insight into performance through cycle stacks.

  • 328.
    Van den Steen, Sam
    et al.
    Univ Ghent, Dept Elect & Informat Syst, Ghent, Belgium..
    Eyerman, Stijn
    Intel, Kontich, Belgium..
    De Pestel, Sander
    Univ Ghent, Dept Elect & Informat Syst, Ghent, Belgium..
    Mechri, Moncef
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Carlson, Trevor E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Black-Schaffer, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Hagersten, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Eeckhout, Lieven
    Univ Ghent, Dept Elect & Informat Syst, Ghent, Belgium..
    Analytical Processor Performance and Power Modeling Using Micro-Architecture Independent Characteristics2016Inngår i: I.E.E.E. transactions on computers (Print), ISSN 0018-9340, E-ISSN 1557-9956, Vol. 65, nr 12, s. 3537-3551Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optimizing processors for (a) specific application(s) can substantially improve energy-efficiency. With the end of Dennard scaling, and the corresponding reduction in energy-efficiency gains from technology scaling, such approaches may become increasingly important. However, designing application-specific processors requires fast design space exploration tools to optimize for the targeted application(s). Analytical models can be a good fit for such design space exploration as they provide fast performance and power estimates and insight into the interaction between an application's characteristics and the micro-architecture of a processor. Unfortunately, prior analytical models for superscalar out-of-order processors require micro-architecture dependent inputs, such as cache miss rates, branch miss rates and memory-level parallelism. This requires profiling the applications for each cache and branch predictor configuration of interest, which is far more time-consuming than evaluating the analytical performance models. In this work we present a micro-architecture independent profiler and associated analytical models that allow us to produce performance and power estimates across a large superscalar out-of-order processor design space almost instantaneously. We show that using a micro-architecture independent profile leads to a speedup of 300x compared to detailed simulation for our evaluated design space. Over a large design space, the model has a 9.3 percent average error for performance and a 4.3 percent average error for power, compared to detailed cycle-level simulation. The model is able to accurately determine the optimal processor configuration for different applications under power or performance constraints, and provides insight into performance through cycle stacks.

  • 329.
    Vasilchenko, Anna
    et al.
    Newcastle Univ, Open Lab, Newcastle, England.
    Cajander, Åsa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Daniels, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Balaam, Madeline
    KTH Royal Inst Technol, Dept Media Technol & Interact Design, Stockholm, Sweden.
    The self-flipped classroom concept: Underlying ideas and experiences2018Inngår i: Proc. 48th ASEE/IEEE Frontiers in Education Conference, Piscataway, NJ: IEEE Press, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the modern fast changing world no formal education is able to provide learners with a complete set of knowledge, skills and competences that they would need to successfully compete on tomorrow's job market. Therefore, the role of universities is increasingly shifting towards provision of an environment where students have a chance to acquire lifelong learning skills. This paper presents underlying ideas of, and practical experiences with, an innovative pedagogy that addresses the lifelong learning skills acquisition along with additional benefits for science and technology students. The proposed approach, called self-flipped classroom (SFC), is built on a synergy of two pedagogies: learning through making and flipped classroom. To unveil the construct of the SFC, we discuss each of its components individually presenting appropriate theoretical grounding. We also report on our experiences from self-flipped classroom implementations in two countries, UK and Sweden, and in three different educational settings. From our work with the SFC concept we have identified four different roles the students can assume in a SFC scenario: creators, collaborators, communicators, and learners. We present our observations regarding the identified roles that have been found in the studied settings. We also outline some implications for teaching using the SFC concept and future research directions in this space.

  • 330.
    Vo, Huu-Phuc
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Berglund, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Daniels, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    A perspective from Vietnamese students on teaching of soft skills2017Inngår i: Proc. 5th International Conference on Learning and Teaching in Computing and Engineering, IEEE Computer Society, 2017, s. 23-24Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Soft skills are significant to the engineering labour market, especially in Information Technology where demands are high on for instance communication skill, teamwork skill, presentation skill, etc. Despite their importance, educating students in using those skills is not fully included in the bachelor education programmes, especially in developing countries. This project aims to gain insights in how soft skills are taught in Vietnamese universities, and which skills are missing in their bachelor education programmes. The findings are intended to support education in order to develop the teaching of soft skills for Vietnamese students, and decrease the unemployment rate of Vietnamese graduates. In this project, semi-structured interviews, by e-mail, have been used to collect the data. There are eight Vietnamese interviewees who have experiences from various education programmes. The interview transcripts were then analysed and categorised into themes. The results of our work are a preliminary identification of missing skills in the undergraduate programmes, and a set of proposed skills that could be considered to improve the education programmes.

  • 331.
    Voogt, Marianne
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Chen, Chuan Sheng
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Thota, Neena
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Academics' Experience of Teaching Open Ended Group Projects A phenomenographic study2016Inngår i: 2016 IEEE FRONTIERS IN EDUCATION CONFERENCE (FIE), 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An Open Ended Group Project (OEGP) is a distinguishable pedagogical tool, used by teachers in computing, engineering, and information technology courses. The tool contributes to the development of 'soft' skills essential for students' future career needs. This paper reports on a phenomenographic study that investigates the research question: What are the ways in which academics teaching Open Ended Group Projects experience teaching the course? Previous studies, using the phenomenographic research approach, have offered insights into academics' conceptions of science learning and teaching. However, there are no studies that investigate the experiences of teachers who use OEGP in their classes. This is the first study, that asks academics using an OEGP how they experience teaching these courses. Students enrolled in a course on computing education research conducted the small-scale study at Uppsala University, Sweden. In order to answer the research question, a theoretical sample was selected with a wide range of relevant population characteristics (e.g. background, prior experience, gender, and age). The semi -structured interview questions focused on understanding of OEGP, the learning objectives of OEGP, strategies for teaching these learning objectives, and the teacher's experience in teaching through OEGP. The results indicate that teachers see their role within OEGP as a coach and that the variation between experiences lies in what is intended to be coached. This variation is presented in a hierarchy (the outcome space). Categories focus on: the team, discipline, problem solving skills, learning and motivation. We also look at the first-hand experience of a student in an OEGP course and discuss the teachers' perceptions of students' experiences of OEGP. The implication for teaching is that a teacher needs to reconsider the way he or she teaches more often in OEGP than in regular courses. There are two reasons for this. First, teaching OEGP is based less on teaching content knowledge and more on teaching skills. Secondly, OEGP deals with a 'real problem', and aspects of the problem continuously change. Teachers are recommended to aim for reaching a higher category, indicating a deeper level of experience, and to use the experience of coaching OEGP in other courses as well. The importance of metacognition (reflection on action) and discussion with other teachers who have experience in teaching OEGP is highlighted.

  • 332.
    Wang, Wendong
    et al.
    Beijing Univ Posts & Telecommun, State Key Lab Networking & Switching Technol, XiTuCheng Rd 10, Beijing 100876, Peoples R China.
    Xi, Teng
    Beijing Univ Posts & Telecommun, State Key Lab Networking & Switching Technol, XiTuCheng Rd 10, Beijing 100876, Peoples R China.
    Ngai, Edith C.-H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Song, Zheng
    Virginia Tech, Dept Comp Sci, Blacksburg, VA 24060 USA.
    Energy-efficient collaborative outdoor localization for participatory sensing2016Inngår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, nr 6, artikkel-id 762Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Location information is a key element of participatory sensing. Many mobile and sensing applications require location information to provide better recommendations, object search and trip planning. However, continuous GPS positioning consumes much energy, which may drain the battery of mobile devices quickly. Although WiFi and cell tower positioning are alternatives, they provide lower accuracy compared to GPS. This paper solves the above problem by proposing a novel localization scheme through the collaboration of multiple mobile devices to reduce energy consumption and provide accurate positioning. Under our scheme, the mobile devices are divided into three groups, namely the broadcaster group, the location information receiver group and the normal participant group. Only the broadcaster group and the normal participant group use their GPS. The location information receiver group, on the other hand, makes use of the locations broadcast by the broadcaster group to estimate their locations. We formulate the broadcaster set selection problem and propose two novel algorithms to minimize the energy consumption in collaborative localization. Simulations with real traces show that our proposed solution can save up to 68% of the energy of all of the participants and provide more accurate locations than WiFi and cellular network positioning.

  • 333. Wang, Wenqi
    et al.
    Wei, Yangjie
    Guan, Nan
    Yi, Wang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    The automatic detection and analysis of electrocardiogram based on Lorenz plot2015Inngår i: Proc. 12th International Conference on Robotics and Biomimetics, Piscataway, NJ: IEEE, 2015, s. 644-649Konferansepaper (Fagfellevurdert)
  • 334.
    Wang, Xiaojie
    et al.
    NeuSoft Corp, Shenyang, Liaoning, Peoples R China; Dalian Univ Technol, Sch Software, Dalian, Peoples R China.
    Ning, Zhaolong
    Dalian Univ Technol, Sch Software, Dalian, Peoples R China; Kyushu Univ, Fukuoka, Fukuoka, Japan.
    Hu, Xiping
    Chinese Acad Sci, Shenzhen Inst Adv Technol, Beijing, Peoples R China.
    Ngai, Edith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Imperial Coll London, London, England.
    Wang, Lei
    Dalian Univ Technol, Sch Software, Dalian, Peoples R China; Bell Labs Res China, Shanghai, Peoples R China; Samsung, Seoul, South Korea; Washington State Univ, Vancouver, WA USA.
    Hu, Bin
    Lanzhou Univ, Sch Informat Sci & Engn, Lanzhou, Gansu, Peoples R China; Tsinghua Univ, Beijing, Peoples R China; Swiss Fed Inst Technol, Zurich, Switzerland; ACM China, Beijing, Peoples R China.
    Kwok, Ricky
    Univ Hong Kong, Hong Kong, Hong Kong, Peoples R China; HKIE, Hong Kong, Hong Kong, Peoples R China; IET, Hong Kong, Hong Kong, Peoples R China.
    A City-Wide Real-Time Traffic Management System: Enabling Crowdsensing in Social Internet of Vehicles2018Inngår i: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 56, nr 9, s. 19-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As an emerging platform based on ITS, SIoV is promising for applications of traffic management and road safety in smart cities. However, the end-to-end delay is large in store-carry-and-forward-based vehicular networks, which has become the main obstacle for the implementation of large-scale SIoV. With the extensive applications of mobile devices, crowdsensing is promising to enable real-time content dissemination in a city-wide traffic management system. This article first provides an overview of several promising research areas for traffic management in SIoV. Given the significance of traffic management in urban areas, we investigate a crowdsensing-based framework to provide timely response for traffic management in heterogeneous SIoV. The participant vehicles based on D2D communications integrate trajectory and topology information to dynamically regulate their social behaviors according to network conditions. A real-world taxi trajectory analysis-based performance evaluation is provided to demonstrate the effectiveness of the designed framework. Furthermore, we discuss several future research challenges before concluding our work.

  • 335.
    Wang, Yang
    et al.
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Guan, Nan
    Hong Kong Polytech Univ, Hong Kong, Hong Kong, Peoples R China..
    Sun, Jinghao
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Lv, Mingsong
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    He, Qingqiang
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    He, Tianzhang
    Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Wang, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Northeastern Univ, Shenyang, Liaoning, Peoples R China..
    Benchmarking OpenMP Programs for Real-Time Scheduling2017Inngår i: 2017 IEEE 23Rd International Conference On Embedded And Real-Time Computing Systems And Applications (RTSCA), IEEE Computer Society, 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Real-time systems are shifting from single-core to multi-core processors. Software must be parallelized to fully utilize the computation power of multi-core architecture. OpenMP is a popular parallel programming framework in general and high-performance computing, and recently has drawn a lot of interests in embedded and real-time computing. Much recent work has been done on real-time scheduling of OpenMP-based parallel workload. However, these studies conduct evaluations with randomly generated task systems, which cannot well represent the structure features of OpenMP workload. This paper presents a benchmark suite, ompTGB, to support research on real-time scheduling of OpenMP-based parallel tasks. ompTGB does not only collect realistic OpenMP programs, but also models them into task graphs so that the real-time scheduling researchers can easily understand and use them. We also present a new response time bound for a subset of OpenMP programs and use it to demonstrate the usage of ompTGB.

  • 336.
    Wang, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    The Cause-Effect Latency Problem in Real-Time Systems2018Inngår i: Formal Methods For Industrial Critical Systems, FMICS 2018 / [ed] Howar, F Barnat, J, SPRINGER INTERNATIONAL PUBLISHING AG , 2018, s. XIII-XIIIKonferansepaper (Fagfellevurdert)
  • 337.
    Wang, Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Towards Customizable CPS: Composability, Efficiency and Predictability2017Inngår i: Formal Methods and Software Engineering / [ed] Duan, Z Ong, L, Springer, 2017, s. 3-15Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Today, many industrial products are defined by software, and therefore customizable by installing new applications on demand - their functionalities are implemented by software and can be modified and extended by software updates. This trend towards customizable products is extending into all domains of IT, including Cyber-Physical Systems (CPS) such as cars, robotics, and medical devices. However, these systems are often highly safety-critical. The current state-of-practice allows hardly any modifications once safety-critical systems are put in operation. This is due to the lack of techniques to preserve crucial safety conditions for the modified system, which severely restricts the benefits of software. This work aims at new paradigms and technologies for the design and safe software updates of CPS at operation-time - subject to stringent timing constraints, dynamic workloads, and limited resources on complex computing platforms. Essentially there are three key challenges: Composability, Resource-Efficiency and Predictability to enable modular, incremental and safe software updates over system life-time in use. We present research directions to address these challenges: (1) Open architectures and implementation schemes for building composable systems, (2) Fundamental issues in real-time scheduling aiming at a theory of multi-resource (inc. multiprocessor) scheduling, and (3) New-generation techniques and tools for fully separated verification of timing and functional properties of real-time systems with significantly improved efficiency and scalability. The tools shall support not only verification, but also code generation tailored for both co-simulation (interfaced) with existing design tools such as Open Modelica (for modeling and simulation of physical components), and deployment on given computing platforms.

  • 338. Wei, Yangjie
    et al.
    Wu, Chengdong
    Yi, Wang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Dong, Zaili
    Efficient shape reconstruction of microlens using optical microscopy2015Inngår i: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 62, nr 12, s. 7655-7664Artikkel i tidsskrift (Fagfellevurdert)
  • 339. Wei, Yangjie
    et al.
    Wu, Chengdong
    Yi, Wang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Wang, Wenxue
    Diffusion-based three-dimensional reconstruction of complex surface using monocular vision2015Inngår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 23, nr 23, s. 30364-30378Artikkel i tidsskrift (Fagfellevurdert)
  • 340. Wei, Yangjie
    et al.
    Yi, Wang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Dynamic blind source separation based on source-direction prediction2016Inngår i: Neurocomputing, ISSN 0925-2312, E-ISSN 1872-8286, Vol. 185, s. 73-81Artikkel i tidsskrift (Fagfellevurdert)
  • 341.
    Winblad, Kjell
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Sagonas, Konstantinos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi.
    Jonsson, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datalogi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Lock-free Contention Adapting Search Trees2018Inngår i: The 30th ACM Symposium on Parallelism in Algorithms and Architectures, SPAA 2018, New York, NY, USA, 2018, Vol. 30Konferansepaper (Fagfellevurdert)
  • 342.
    Xi, Teng
    et al.
    Beijing Univ Posts & Telecommun, State Key Lab Networking & Switching Technol, Beijing, Peoples R China..
    Ngai, Edith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Song, Zheng
    Virginia Tech, Dept Comp Sci, Blacksburg, VA USA..
    Tian, Ye
    Beijing Univ Posts & Telecommun, State Key Lab Networking & Switching Technol, Beijing, Peoples R China..
    Gong, Xiangyang
    Beijing Univ Posts & Telecommun, State Key Lab Networking & Switching Technol, Beijing, Peoples R China..
    Wang, Wendong
    Beijing Univ Posts & Telecommun, State Key Lab Networking & Switching Technol, Beijing, Peoples R China..
    Collaborative Localization in Participatory Sensing with Load Balancing2015Inngår i: 2015 IEEE 23Rd International Symposium On Quality Of Service (IWQOS), 2015, s. 61-62Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The increasingly popular smartphones enable participatory sensing systems to collect location-based sensing data for different tasks. However, GPS positioning is very energy consuming, which could drain a mobile device's battery quickly. High energy consumption may threaten the participants and reduce the sustainability of the participatory sensing systems. In this paper, we propose a collaborative localization strategy with load balancing. Simulations with real traces showed that our proposed solution can save more than 80% of the energy consumption for localization in the entire network with load balancing.

  • 343.
    Xi, Teng
    et al.
    Beijing Univ Posts & Telecommun, State Key Lab Networking & Switching Technol, Beijing, Peoples R China.
    Wang, Wendong
    Beijing Univ Posts & Telecommun, State Key Lab Networking & Switching Technol, Beijing, Peoples R China.
    Ngai, Edith C-H
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Liu, Xiuming
    Uppsala Univ, Div Comp Syst, Dept Informat Technol, Uppsala, Sweden.
    Spatio-Temporal Aware Collaborative Mobile Sensing with Online Multi-Hop Calibration2018Inngår i: Proceedings of the 2018 the Nineteenth International Symposium on Mobile Ad Hoc Networking and Computing (MOBIHOC '18), Association for Computing Machinery (ACM), 2018, s. 310-311Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Real-time accurate air quality data is very important for pollution exposure monitoring and urban planning. However, there are limited high-quality air quality monitoring stations (AQMS) in cities due to their high equipment costs. To provide real-time and accurate data covering large area, this paper proposes a novel scheme that jointly considers online multi-hop calibration and spatio-temporal coverage in route selection for mobile sensors. A novel sensor carrier selection problem (SCSP) is formulated, which aims to maximize the spatio-temporal coverage ratio and guarantee the accuracy of measurements through sensor calibration. An online Bayesian based collaborative calibration (OBCC) scheme is proposed to relax the multi-hop calibration constraint in the SCSP. Based on the OBCC, a multi-hop calibration judgment algorithm (MCJA) is proposed to decide whether the data accuracy of a given set of routes can be guaranteed through collaborative calibration. Furthermore, a heuristic sensor route selection algorithm (SRSA) is then developed to solve the SCSP.

  • 344. Xu, Gang
    et al.
    Ngai, Edith C.-H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Liu, Jiangchuan
    Ubiquitous transmission of multimedia sensor data in Internet of Things2018Inngår i: IEEE Internet of Things Journal, ISSN 2327-4662, Vol. 5, nr 1, s. 403-414Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Internet of Things (IoT) enables environmental monitoring by collecting data from sensing devices, including cameras and microphones. The popularity of smartphones enables mobile users to communicate and collect data from their surrounding sensing devices. The mobile devices can obtain useful environmental data from nearby sensors through short-range communication such as Bluetooth. Nevertheless, the limited contact time and the wireless capacity constrain the amount of data to be collected. With the increasing amount of multimedia big data such as videos and pictures from cameras, it is crucial for mobile users to collect prioritized data that can maximize their data utility. In this paper, we propose a distributed algorithm to provide information-centric ubiquitous data collection of multimedia big data by mobile users in the IoT. The algorithm can handle transmissions of multimedia big data recorded by the surrounding cameras and sensors, and prioritize the transmissions of the most important and relevant data. The mobile users construct data collection trees adaptively according to their dynamic moving speeds and the value of information carried by the multimedia and sensor data. The distributed algorithm can support smooth data collection and coordination of multiple mobile users. We provide both numerical analysis and extensive simulations to evaluate the information value, energy efficiency and scalability of our solution. The results showed that our distributed algorithm can improve the value of information up to 50% and reduce energy consumption to half compared with existing approach. Our algorithm also scales perfectly well with increasing number of mobile users and dynamic moving speeds.

  • 345.
    Yan, Wenqing
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Flinta, Christofer
    Ericsson Res, Stockholm, Sweden.
    Johnsson, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Ericsson Res, Stockholm, Sweden.
    Machine-Learning Based Active Measurement Proxy for IoT Systems2019Inngår i: 2019 IFIP/IEEE Symposium On Integrated Network And Service Management (IM), IEEE, 2019, s. 198-206Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Network operators are accustomed to using IP-layer active measurements for assessing end-to-end network performance and expect that new technology, such as IoT, provides similar means. Unfortunately, active measurements in IoT systems are associated with both energy and network overhead. This paper presents and evaluates a novel active-measurement proxy approach, based on machine learning, that enables reduction of active measurement overhead in IoT systems. The paper describes the approach and its implementation. Further, the approach is evaluated in a IEEE 802.15.4 testbed, and the results show high-performing and accurate modeling.

  • 346. Yang, Y.
    et al.
    Tian, Y.
    Ngai, Edith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Zhang, L.
    Teng, Y.
    Wang, W.
    Vulnerable Friend Identification: Who Should You Beware of Most in Online Social Networks2015Inngår i: 2015 IEEE Global Communications Conference (Globecom), 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Web users are immersed in their roles as information producers and propagation pushers. They are unaware of being potential threats to privacy-protection towards themselves and their friends. It is necessary to know who they should beware of most in their friend-networks once their privacy information is divulged inadvertently. In this paper, we aim to identify the vulnerable friend who maximizes the dissemination of privacy information. First we develop a Privacy Receiving-Disseminating (PRD) model to simulate the iterative course of privacy information dissemination within social graph. The subgraph constituted of those users who are involved in the dissemination, called Ultimate Circle of Disseminating (UCD), is then detected by an iterative algorithm. The contribution of each direct friend could be evaluated by comparing the disseminating intensities of detected UCDs before and after unfriending himself. The performance of our work has been validated empirically with the comparison of different unfriending strategies.

  • 347.
    Zeljic, Aleksandar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datorteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Approximations and abstractions for reasoning about machine arithmetic2016Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Safety-critical systems rely on various forms of machine arithmetic to perform their tasks: integer arithmetic, fixed-point arithmetic or floating-point arithmetic. The problem with machine arithmetic is that it can exhibit subtle differences in behavior compared to the ideal mathematical arithmetic, due to fixed-size representation in memory. Failure of safety-critical systems is unacceptable, because it can cost lives or huge amounts of money, time and effort. To prevent such incidents, we want to formally prove that systems satisfy certain safety properties, or otherwise discover cases when the properties are violated. However, for this we need to be able to formally reason about machine arithmetic. The main problem with existing approaches is their inability to scale well with the increasing complexity of systems and their properties. In this thesis, we explore two alternatives to bit-blasting, the core procedure lying behind many common approaches to reasoning about machine arithmetic.

    In the first approach, we present a general approximation framework which we apply to solve constraints over floating-point arithmetic. It is built on top of an existing decision procedure, e.g., bit-blasting. Rather than solving the original formula, we solve a sequence of approximations of the formula. Initially very crude, these approximations are frequently solved very quickly. We use results from these approximations to either obtain a solution, obtain a proof of unsatisfiability or generate a new approximation to solve. Eventually, we will either have found a solution or a proof that solution does not exist. The approximation framework improves the solving time and can solve a number of formulas that the bit-blasting cannot.

    In the second approach, we present a novel method to reason about the theory of fixed-width bit-vectors. This new decision procedure is called mcBV and it is based on the model constructing satisfiability calculus (mcSAT). The procedure uses a lazy representation of bit-vectors and attempts to avoid bit-blasting altogether. It is able to reason about bit-vectors on both bit- and word-level, leveraging both Boolean constraint propagation and native arithmetic reasoning. It also features a greedy explanation generalization mechanism and is capable of more general learning compared to existing approaches. mcBV is able to reason about bit-vectors with sizes that significantly exceed the usual 32, 64 and 128 bits. Evaluation of mcBV shows an improvement in performance (compared to bit-blasting) on several classes of problems.

    Delarbeid
    1. An approximation framework for solvers and decision procedures
    Åpne denne publikasjonen i ny fane eller vindu >>An approximation framework for solvers and decision procedures
    2017 (engelsk)Inngår i: Journal of automated reasoning, ISSN 0168-7433, E-ISSN 1573-0670, Vol. 58, nr 1, s. 127-147Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-305180 (URN)10.1007/s10817-016-9393-1 (DOI)000392387400006 ()
    Prosjekter
    UPMARC
    Tilgjengelig fra: 2016-11-10 Laget: 2016-10-12 Sist oppdatert: 2018-01-14bibliografisk kontrollert
    2. Deciding bit-vector formulas with mcSAT
    Åpne denne publikasjonen i ny fane eller vindu >>Deciding bit-vector formulas with mcSAT
    2016 (engelsk)Inngår i: Theory and Applications of Satisfiability Testing: SAT 2016, Springer, 2016, s. 249-266Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Springer, 2016
    Serie
    Lecture Notes in Computer Science, ISSN 0302-9743 ; 9710
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-305182 (URN)10.1007/978-3-319-40970-2_16 (DOI)000387430600016 ()978-3-319-40969-6 (ISBN)
    Konferanse
    SAT 2016, July 5–8, Bordeaux, France
    Prosjekter
    UPMARC
    Tilgjengelig fra: 2016-06-11 Laget: 2016-10-12 Sist oppdatert: 2018-01-14bibliografisk kontrollert
  • 348.
    Zeljic, Aleksandar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Backeman, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Wintersteiger, Christoph M.
    Microsoft Research, Cambridge, UK.
    Rümmer, Philipp
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Exploring Approximations for Floating-Point Arithmetic using UppSAT2018Inngår i: Automated Reasoning / [ed] Didier Galmiche, Stephan Schulz, Roberto Sebastiani, Springer, 2018, s. 246-262Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We consider the problem of solving floating-point constraints obtained from software verification. We present UppSAT—an new implementation of a systematic approximation refinement framework as an abstract SMT solver. Provided with an approximation and a decision procedure (implemented in an off-the-shelf SMT solver), UppSAT yields an approximating SMT solver. Additionally, UppSAT includes a library of predefined approximation components which can be combined and extended to define new encodings, orderings and solving strategies. We propose that UppSAT can be used as a sandbox for easy and flexible exploration of new approximations. To substantiate this, we explore encodings of floating-point arithmetic into reduced precision floating-point arithmetic, real-arithmetic, and fixed-point arithmetic (encoded into the theory of bit-vectors in practice). In an experimental evaluation we compare the advantages and disadvantages of approximating solvers obtained by combining various encodings and decision procedures.

  • 349.
    Zeljic, Aleksandar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Wintersteiger, Christoph M.
    Rümmer, Philipp
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    An approximation framework for solvers and decision procedures2017Inngår i: Journal of automated reasoning, ISSN 0168-7433, E-ISSN 1573-0670, Vol. 58, nr 1, s. 127-147Artikkel i tidsskrift (Fagfellevurdert)
  • 350.
    Zeljic, Aleksandar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Wintersteiger, Christoph M.
    Rümmer, Philipp
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Deciding bit-vector formulas with mcSAT2016Inngår i: Theory and Applications of Satisfiability Testing: SAT 2016, Springer, 2016, s. 249-266Konferansepaper (Fagfellevurdert)
45678 301 - 350 of 363
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