Electrical & Computer Engineering Research Works

Permanent URI for this collectionhttp://hdl.handle.net/1903/1658

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Author: search.filters.author.Potkonjak, MiodragSubject: search.filters.subject.quality of service (QoS)

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Now showing 1 - 4 of 4
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    System Synthesis of Synchronous Multimedia Applications
    (IEEE, 1999-11) Qu, Gang; Mesarina, Malena; Potkonjak, Miodrag
    Modern system design is being increasingly driven by applications such as multimedia and wireless sensing and communications, which all have intrinsic quality of service (QoS) requirements, such as throughput, error-rate, and resolution. One of the most crucial QoS guarantees that the system has to provide is the timing constraints among the interacting media (synchronization) and within each media (latency). We have developed the first framework for systems design with timing QoS guarantees, latency and synchronization. In particular, we address how to design system-on-chip with minimal silicon area to meet timing constraints. We propose the two-phase design methodology. In the first phase, we select an architecture which facilitates the needs of synchronous low latency applications well. In the second phase, for a given processor configuration, we use our new scheduler in such a way that storage requirements are minimized. We have develop scheduling algorithms that solve the problem optimally for a-priori specified applications. The algorithms have been implemented and their effectiveness demonstrated on a set of simulated MPEG streams from popular movies.
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    Achieving Utility Arbitrarily Close to the Optimal with Limited Energy
    (IEEE, 2000-07) Qu, Gang; Potkonjak, Miodrag
    Energy is one of the limited resources for modern systems, especially the battery-operated devices and personal digi- tal assistants. The backlog in new technologies for more powerful battery is changing the traditional system design philosophies. For example, due to the limitation on battery life, it is more realistic to design for the optimal benefit from limited resource rather than design to meet all the applica- tions' requirement. We consider the following problem: a system achieves a certain amount of utility from a set of applications by providing them certain levels of quality of service (QoS). We want to allocate the limited system re- sources to get the maximal system utility. We formulate this utility maximization problem, which is NP-hard in gen- eral, and propose heuristic algorithms that are capable of finding solutions provably arbitrarily close to the optimal. We have also derived explicit formulae to guide the alloca- tion of resources to actually achieve such solutions. Simu- lation shows that our approach can use 99.9% of the given resource to achieve 25.6% and 32.17% more system utilities over two other heuristics, while providing QoS guarantees to the application program.
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    Power Minimization using System-Level Partitioning of Applications with Quality of Service Requirements
    (1999-11) Qu, Gang; Potkonjak, Miodrag
    Design systems to provide various quality of service (QoS) guarantees has received a lot of attentions due to the increasing popularity of real-time multimedia and wireless communication applications. Meanwhile, low power consumption is always one of the goals for system design, especially for battery-operated systems. With the design trend of integrating multiple processor cores and memory on a single chip, we address the problem of how to partition a set of applications among processors, such that all the individual QoS requirements are met and the total energy consumption is minimized. We exploit the advantages provided by the variable voltage design methodology to choose the voltage for each application on the same processor optimally for this purpose. We also discuss how to partition applications among the processors to achieve the same goal. We formulate the problem on an abstract QoS model and present how to allocate resources (e.g., CPU time) and determine the voltage profile for every single processor. Experiments on media benchmarks have also been studied.
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    Power Minimization in QoS Sensitive Systems
    (IEEE, 2004-06) Wong, Jennifer L; Qu, Gang; Potkonjak, Miodrag
    The majority of modern multimedia and mobile systems have two common denominators: quality-of-service (QoS) requirements, such as latency and synchronization, and strict energy constraints. However, until now no synthesis techniques have been proposed for the design and efficient use of such systems.We have two main objectives: conceptual and synthesis. The conceptual objective is to develop a generic practical technique for the automatic development of online adaptive algorithms from efficient off-line algorithms using statistical techniques. The synthesis objective is to introduce the first design technique for QoS low-power synthesis. We introduce a system of provablyoptimal techniques that minimize energy consumption of streamoriented applications under two main QoS metrics: latency and synchronization. Specifically, we study how multiple voltages can be used to simultaneously satisfy hardware constraints and minimize power consumption while preserving the requested level of QoS. The purpose of the off-line algorithm is threefold. First, it is used as input to statistical software which is used to identify important and relevant parameters of the processes. Second, the algorithm provides buffer occupancy rate indicators. Lastly, it provides a way to combine buffer occupancy and QoS metrics to form a fast and efficient online algorithm. The effectiveness of the algorithms is demonstrated on a number of standard multimedia benchmarks.