Twan Basten

Technische Universiteit Eindhoven, Eindhoven, North Brabant, Netherlands

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Publications (201)26.48 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: General purpose platforms are characterized by unpredictable timing behavior. Real-time schedules of tasks on general purpose platforms need to be robust against variations in task execution times. We defi�ne robustness in terms of the expected number of tasks that miss deadlines. We present an iterative robust scheduler that produces robust multiprocessor schedules of directed acyclic graphs with a low expected number of tasks that miss their deadlines. We experimentally show that this robust scheduler produces signi�ficantly more robust schedules in comparison to a scheduler using nominal execution times on both real world and synthetic test cases.
    23rd International Conference on Real-Time Networks and Systems, Lille, France; 11/2015
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    ABSTRACT: CPS play an important role in the modern high-tech industry. Designing such systems is a challenging task due to the multi-disciplinary nature of these systems, and the range of abstraction levels involved. To facilitate hands-on experience with such systems, we develop a cyber-physical platform that aids in research and education on CPS. This paper describes this platform, which contains all typical CPS components. The platform is used in various research and education projects for bachelor, master, and PhD students. We discuss the platform and a number of projects and the educational opportunities they provide.
    WESE Workshop 2015; 09/2015
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    Xue-Yang Zhu · Marc Geilen · Twan Basten · and Sander Stuijk ·
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    DESCRIPTION: Technical Report (2011) [ISCAS-SKLCS-11-53]: Synchronous dataflow graphs (SDFGs) are widely used to model multi-rate digital signal processing (DSP) algorithms. A lower iteration period of such a model implies a faster execution of a DSP algorithm. Retiming is a simple but efficient graph transformation technique for performance optimization, which can decrease the iteration period without affecting functionality. In this paper, we deal with the iteration period minimization problem — retiming an SDFG to achieve the smallest possible iteration period. We present a heuristic method that works directly on SDFGs, without converting them to their equivalent homogeneous SDFGs. It analyzes the state-space generated by a self-timed execution of the SDFG to obtain a near-optimal retiming. Our experimental results show that in 85% of the test cases that allow actors to fire autoconcurrently, our method gets reduced iteration periods close to the optimal ones, while being ten times faster than the state-of-the-art exact method; in all the test cases in which auto-concurrent firing of actors is excluded, our method gets reduced iteration periods almost the same as the optimal ones, while being 100 times faster than the exact method. Combining parts of the exact method with our novel method, we present an improved algorithm, whose execution time is further reduced by 22%.
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    ABSTRACT: A Large Scale Printer (LSP) is a Cyber Physical System (CPS) printing thousands of sheets per day with high quality. The print requests arrive at run-time requiring online scheduling. We capture the LSP scheduling problem as online scheduling of re-entrant flowshops with sequence dependent setup times and relative due dates with makespan minimization as the scheduling criterion. Exhaustive approaches like Mixed Integer Programming can be used, but they are compute intensive and not suited for online use. We present a novel heuristic for scheduling of LSPs that on average requires 0.3 seconds per sheet to find schedules for industrial test cases. We compare the schedules to lower bounds, to schedules generated by the current scheduler and schedules generated by a modified version of the classical NEH (MNEH) heuristic [1], [2]. On average, the proposed heuristic generates schedules that are 40% shorter than the current scheduler, have an average difference of 25% compared to the estimated lower bounds and generates schedules with less than 67% of the makespan of schedules generated by the MNEH heuristic.
    Design, Automation and Test in Europe, DATE 15, Grenoble, France; 03/2015
  • Marcel Steine · Marc Geilen · Twan Basten ·
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    ABSTRACT: Wireless Sensor Networks (WSNs) are commonly deployed in dynamic environments where events, such as moving sensor nodes and changing external interference, impact the performance, or Quality of Service (QoS), of the network. QoS isexpressed by the values of multiple, possibly conflicting, network quality metrics, such as network lifetime and maximum latency of communicating a packet to the sink. Sufficient QoS should be provided by the WSN to ensure that the end-user can successfully use the WSN to perform its application. We propose a distributed reconfiguration approach that actively maintains a sufficient level of QoS at runtime for a heterogeneous WSN in a dynamic environment. Every node uses a feedback control strategy to resolve any difference between the current and required QoS of the network by adapting controllable parameters of the protocol stack. Example parameters are the transmission power and maximum number of packet retransmissions. Nodes collaborate such that, with the combined adaptations, the required network QoS is achieved. The behavior of the reconfiguration approach and the tradeoffs involved are analyzed in detail. With the use of simulations and experiments with actual deployments, we show that our approach allows a better optimization of QoS objectives while constraints are met; for example, it achieves the same packet loss with a significantly longer lifetime, compared to current (re-)configuration approaches.
    ACM Transactions on Sensor Networks 03/2015; 11(2):1-41. DOI:10.1145/2663354 · 1.39 Impact Factor
  • F. Comaschi · S. Stuijk · T. Basten · H. Corporaal ·
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    ABSTRACT: Object detection and tracking is one of the most important components in computer vision applications. To carefully evaluate the performance of detection and tracking algorithms, it is important to develop benchmark data sets. One of the most tedious and error-prone aspects when developing benchmarks, is the generation of the ground truth. This paper presents FAST-GT (FAst Semi-automatic Tool for Ground Truth generation), a new generic framework for the semiautomatic generation of ground truths. FAST-GT reduces the need for manual intervention thus speeding-up the ground-truthing process.
  • Source
    Vinh Bui · Paul Brandt · Hang Liu · Twan Basten · Johan Lukkien ·
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    ABSTRACT: Crucial to the success of Body Area Sensor Networks is the flexibility with which stakeholders can share, extend and adapt the system with respect to sensors, data and func-tionality. The first step is to develop an interoperable plat-form with explicit interfaces, which takes care of common management tasks. Beyond that, interoperability is defined by semantics. This paper presents the analysis, design, im-plementation and evaluation of a semantic layer within an existing BASN platform for the purpose of improving the semantic interoperability among sensor networks and appli-cations. We adopt an ontology-based approach but rather than having a single overall ontology, we find that using clear semantic domains and mappings between them improves composability and reduces interoperability problems. We discuss the design choices and a reference implementation on an Android phone and actual sensor devices. We show by a qualitative evaluation that this semantic interoperabil-ity indeed provides significant improvements in flexibility.
    9th International Conference on Body Area Networks (BodyNets 2014), London, Great Britain; 10/2014
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    Paul Brandt · Twan Basten · Sander Stuijk ·
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    ABSTRACT: Patient observations in health care, subjective surveys in social research or dyke sensor data in water management are all examples of measurements. Several ontologies already exist to express measurements, W3C's SSN ontology being a prominent example. However, these ontologies address quantities and properties as being equal, and ignore the foundation required to establish comparability between sensor data. Moreover, a measure of an observation in itself is almost always inconclusive without the context in which the measure was obtained. ContoExam addresses these aspects, providing for a unifying capability for context-aware expressions of observations about quantities and properties alike, by aligning them to ontological foundations, and by binding observations inextricably with their context.
    Formal Ontologies in Information Systems 2014, Rio de Janeiro, Brasil; 09/2014
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    ABSTRACT: Exploration of design alternatives and estimation of their key performance metrics such as latency and energy consumption is essential for making the proper design decisions in the early phases of system development. Often, high-level models of the dynamic behavior of the system are used for the analysis of design alternatives. Our work presents a blueprint for building efficient and re-usable models for this purpose. It builds on the well-known Y-chart pattern in that it gives more structure for the proper modeling of interaction on shared resources that plays a prominent role in software-intensive embedded systems. We show how the blueprint can be used to model a small yet illustrative example system with the Uppaal tool, and with the Java general-purpose programming language, and reflect on their respective strengths and weaknesses. The Java-based approach has resulted in a very flexible and fast discrete-event simulator with many re-usable components. It currently is used by TNO-ESI and Océ-Technologies B.V. for early model-based performance analysis that supports the design process for professional printing systems.
    International Journal on Software Tools for Technology Transfer 08/2014; DOI:10.1007/s10009-014-0340-3
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    ABSTRACT: Tasks executing on general purpose multiprocessor platforms exhibit variations in their execution times. As such, there is a need to explicitly consider robustness, i.e., tolerance to these fluctuations. This work aims to quantify the robustness of schedules of directed acyclic graphs (DAGs) on multiprocessors by defining probabilistic robustness metrics and to present a new approach to perform robustness analysis to obtain these metrics. Stochastic execution times of tasks are used to compute completion time distributions which are then used to compute the metrics. To overcome the difficulties involved with the max operation on distributions, a new curve fitting approach is presented using which we can derive a distribution from a combination of analytical and limited simulation based results. The approach has been validated on schedules of time-critical applications in ASML wafer scanners.
    International Conference on Embedded Computer Systems: Architectures, Modeling, and Simulation (SAMOS XIV), 2014, Agios Konstantinos; 07/2014
  • Majid Nabi · Marc Geilen · Twan Basten · Milos Blagojevic ·
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    ABSTRACT: Node mobility is a key feature of using Wireless Sensor Networks (WSNs) in many sensory applications, such as healthcare. The Medium Access Control (MAC) protocol should properly support the mobility in the network. In particular, mobility is complicated for contention-free protocols like Time Division Multiple Access (TDMA). An efficient access to the shared medium is scheduled based on the node's local neighborhood. This neighborhood may vary over time due to node movement or other dynamics. In scenarios including body-area networking, for instance, some clusters of nodes move together, creating further challenges but also opportunities. This article presents a MAC protocol, MCMAC, that provides efficient support for cluster mobility in TDMA-based MAC protocols in WSNs. The proposed protocol exploits a hybrid contention-free and contention-based communication approach to support cluster mobility. This relieves the protocol from rescheduling demand due to frequent node movements. Moreover, we propose a listening scheduling mechanism to avoid idle listening to mobile nodes that leads to a considerable energy saving for sensor nodes. The protocol is validated by performing several experiments in a real-world large-scale deployment including several mobile clusters. The protocol is also evaluated by extensive simulation of networks with various scales and configurations.
    ACM Transactions on Sensor Networks 06/2014; 10(4):1-32. DOI:10.1145/2594793 · 1.39 Impact Factor
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    Xue-Yang Zhu · Marc Geilen · Twan Basten · Sander Stuijk ·
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    ABSTRACT: Synchronous dataflow graphs (SDFGs) are widely used to model digital signal processing (DSP) and streaming media applications. In this paper, we use retiming to optimize SDFGs to achieve a high throughput with low storage requirement. Using a memory constraint as an additional enabling condition, we define a memory constrained self-timed execution of an SDFG. Exploring the state-space generated by the execution, we can check whether a retiming exists that leads to a rate-optimal schedule under the memory constraint. Combining this with a binary search strategy, we present a heuristic method to find a proper retiming and a static scheduling which schedules the retimed SDFG with optimal rate (i.e., maximal throughput) and with as little storage space as possible. Our experiments are carried out on hundreds of synthetic SDFGs and several models of real applications. Differential synthetic graph results and real application results show that, in 79% of the tested models, our method leads to a retimed SDFG whose rate-optimal schedule requires less storage space than the proven minimal storage requirement of the original graph, and in 20% of the cases, the returned storage requirements equal the minimal ones. The average improvement is about 7.3%. The results also show that our method is computationally efficient.
    17th Design, Automation and Test in Europe, DATE2014, Dresden, Germany; 03/2014
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    ABSTRACT: The timed dataflow model of computation is a useful performance analysis tool for Electronic System Level Design automation and embedded software synthesis. It is used to model systems, including platform mapping and resource scheduling, of components communicating and synchronizing in regular patterns. Its determinism gives it strong analysability properties and makes it less subject to state-space explosion problems. Because of its monotonic temporal behaviour it can provide hard real-time guarantees on throughput and latency. It is expressive enough to cover a fairly large class of applications and platforms. The trend however, in both embedded applications and their platforms is to become more dynamic, reaching the limits of what the model can express and analyse with tight performance guarantees. Scenario-aware dataflow (SADF) is an extension that allows more dynamism to be expressed, introducing a controlled amount of non-determinism into the model to represent different scenarios of behaviour. The combination of a relatively infrequent switching between scenarios and still deterministic dataflow behaviour within scenarios stretches the expressiveness of the model while keeping
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    ABSTRACT: Gossip-based Wireless Sensor Networks (GWSNs) are complex systems of inherently random nature. Planning and designing GWSNs requires a fast and adequately accurate mechanism to estimate system performance. As a first contribution, we propose a performance analysis technique that simulates the gossip-based propagation of each single piece of data in isolation. This technique applies to GWSNs in which the dissemination of data from a specific sensor does not depend on dissemination of data generated by other sensors. We model the dissemination of a piece of data with a Stochastic-Variable Graph Model (SVGM). A SVGM is a weighted-graph abstraction in which the edges represent stochastic variables that model propagation delays between neighboring nodes. Latency and reliability performance properties are obtained efficiently through a stochastic shortest-path analysis on the SVGM using Monte Carlo (MC) simulation. The method is accurate and fast, applicable for both partial and complete system analysis. It outperforms traditional discrete-event simulation. As a second contribution, we propose a centrality-based stratification method that combines structural network analysis and MC partial simulation, to further increase efficiency of the system-level analysis while maintaining adequate accuracy. We analyzed the proposed performance evaluation techniques through an extensive set of experiments, using a real deployment and simulations at different levels of abstraction.
    Simulation 01/2014; 90(1):103-126. DOI:10.1177/0037549713515028 · 0.82 Impact Factor
  • Majid Nabi · Marc M.C.W. Geilen · Twan A.A. Basten ·
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    ABSTRACT: Sensor nodes in many Wireless Body Area Network (WBAN) architectures are supposed to deliver sensed data to a gateway node on the body. To satisfy the data delivery requirements, the network needs to adapt itself to the changes in connection status of the body nodes to the gateway. As a prerequisite, Link Quality Estimation (LQE) needs to be done to detect the connection status of the nodes. The quality of links in WBANs is highly time-varying. The LQE technique should be agile to react fast to such link quality dynamics while avoiding frequent fluctuations to reduce the network adaptation overhead. In this paper, we present an empirical study on using different LQE methods for detecting the connection status of body nodes to the gateway in WBANs. A set of experiments using 16 wireless motes deployed on a body are performed to log the behavior of the wireless links. We explore the trade-offs made by each LQE method in terms of agility, stability, and reliability in detecting connection changes by analyzing the experimental data. Moreover, different LQE methods are used in an adaptive multi-hop WBAN mechanism, as a case study, and their impact on the Quality-of-Services (QoS) are investigated.
    Proceedings of the 16th ACM international conference on Modeling, analysis & simulation of wireless and mobile systems; 11/2013
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    ABSTRACT: In recent years accurate algorithms for detecting objects in images have been developed. Among these algorithms, the object detection scheme proposed by Viola and Jones gained great popularity, especially after the release of high-quality face classifiers by the OpenCV group. However, as any other sliding-window based object detector, it is affected by a strong increase in the computational cost as the size of the scene grows. Especially in real-time applications, a search strategy based on a sliding window can be computationally too expensive. In this paper, we propose an efficient approach to adapt at run time the sliding window step size in order to speed-up the detection task without compromising the accuracy. We demonstrate the effectiveness of the proposed Run-time Adaptive Sliding Window (RASW) in improving the performance of Viola-Jones object detection by providing better throughput-accuracy tradeoffs. When comparing our approach with the OpenCV face detection implementation, we obtain up to 2.03x speedup in frames per second without any loss in accuracy.
    2013 Seventh International Conference on Distributed Smart Cameras (ICDSC); 10/2013
  • Hamid Shojaei · Twan Basten · Marc Geilen · Azadeh Davoodi ·
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    ABSTRACT: Many combinatorial optimization problems in the embedded systems and design automation domains involve decision making in multidimensional spaces. The multidimensional multiple-choice knapsack problem (MMKP) is among the most challenging of the encountered optimization problems. MMKP problem instances appear for example in chip multiprocessor runtime resource management and in global routing of wiring in circuits. Chip multiprocessor resource management requires solving MMKP under real-time constraints, whereas global routing requires scalability of the solution approach to extremely large MMKP instances. This article presents a novel MMKP heuristic, CPH (for Compositional Pareto-algebraic Heuristic), which is a parameterized compositional heuristic based on the principles of Pareto algebra. Compositionality allows incremental computation of solutions. The parameterization allows tuning of the heuristic to the problem at hand. These aspects make CPH a very versatile heuristic. When tuning CPH for computation time, MMKP instances can be solved in real time with better results than the fastest MMKP heuristic so far. When tuning CPH for solution quality, it finds several new solutions for standard benchmarks that are not found by any existing heuristic. CPH furthermore scales to extremely large problem instances. We illustrate and evaluate the use of CPH in both chip multiprocessor resource management and in global routing.
    ACM Transactions on Design Automation of Electronic Systems 10/2013; 18(4). DOI:10.1145/2541012.2541014 · 0.69 Impact Factor
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    ABSTRACT: Synchronous dataflow graphs (SDFGs) are used extensively to model streaming applications. An SDFG can be extended with scheduling decisions, allowing SDFG analysis to obtain properties, such as throughput or buffer sizes for the scheduled graphs. Analysis times depend strongly on the size of the SDFG. SDFGs can be statically scheduled using static-order schedules. The only generally applicable technique to model a static-order schedule in an SDFG is to convert it to a homogeneous SDFG (HSDFG). This may lead to an exponential increase in the size of the graph and to suboptimal analysis results (e.g., for buffer sizes in multiprocessors). We present techniques to model two types of static-order schedules, i.e., periodic schedules and periodic single appearance schedules, directly in an SDFG. Experiments show that both techniques produce more compact graphs compared to the technique that relies on a conversion to an HSDFG. This results in reduced analysis times for performance properties and tighter resource requirements.
    IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems 10/2013; 32(10):1495-1508. DOI:10.1109/TCAD.2013.2265852 · 1.00 Impact Factor
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    ABSTRACT: Latest trends in embedded platform architectures show a steady shift from high frequency single core platforms to lower-frequency but highly-parallel execution platforms. Scheduling applications with stringent latency requirements on such multiprocessor platforms is challenging. Our work is motivated by the scheduling challenges faced by ASML, the world's leading provider of wafer scanners. A wafer scanner is a complex cyber-physical system that manipulates silicon wafers with extreme accuracy at high throughput. Typical control applications of the wafer scanner consist of thousands of precedence-constrained tasks with latency requirements. Machines are customized so that precise characteristics of the control applications to be scheduled and the execution platform are only known during machine start-up. This results in large-scale scheduling problems that need to be solved during start-up of the machine under a strict timing constraint on the schedule delivery time. This paper introduces a fast and scalable static-order scheduling approach for applications with stringent latency requirements and a fixed binding on multiprocessor platforms. It uses a heuristic that makes scheduling decisions based on a new metric to find feasible schedules that meet timing requirements as quickly as possible and it is shown to be scalable to very large task graphs. The computation of this metric exploits the binding information of the application. The approach will be incorporated into the ASML's latest generation of wafer scanners.
    Proceedings of the 2013 Euromicro Conference on Digital System Design; 09/2013
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    Hamid Shojaei · Azadeh Davoodi · Twan Basten ·
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    ABSTRACT: This paper presents a collaborative procedure for multiobjective global routing. Our procedure takes multiple global routing solutions, which are generated independently (e.g., by one router that runs in different modes concurrently or by different routers running in parallel), as input. It then performs multiobjective optimization based on Pareto algebra and quickly generates multiple global routing solutions with a tradeoff between the considered objectives. The user can control the number of generated solutions and the degree of exploring the tradeoff between them by constraining the maximum allowable degradation in each objective. This paper then considers the following three multiobjective case studies: 1) minimization of interconnect power and wirelength; 2) minimization of routing congestion and wirelength; and 3) minimization of wirelength with respect to the (finite-capacity) routing resources. The maximum allowable degradation in wirelength is specified in all cases. Our multiobjective procedure runs in only a few minutes for each of the International Symposium on Physical Design 2008 benchmarks, even the unroutable ones, which imposes a tolerable overhead in the design flow. In our simulations, we demonstrate the effectiveness of our procedure using five modern academic global routers.
    IEEE Transactions on Very Large Scale Integration (VLSI) Systems 07/2013; 21(7):1308-1321. DOI:10.1109/TVLSI.2012.2205717 · 1.36 Impact Factor

Publication Stats

3k Citations
26.48 Total Impact Points


  • 1995-2014
    • Technische Universiteit Eindhoven
      • • Department of Electrical Engineering
      • • Embedded Systems Institute (ESI)
      • • Department of Mathematics and Computer Science
      Eindhoven, North Brabant, Netherlands
  • 2013
    • Schneider Electric
      Rueil, Île-de-France, France
    • Cork Institute of Technology
      Corcaigh, Munster, Ireland
  • 2010-2013
    • Embedded Systems Institute
      Eindhoven, North Brabant, Netherlands