The primary design goal of many embedded systems for multimedia applications is usually meeting the performance requirement at a minimum cost. In this thesis, we proposed two different ILP based approaches for hardware/software (HW/SW) partitioning and pipelined scheduling of embedded systems for multimedia applications. One ILP approach solves the HW/SW partitioning and pipelined scheduling problem simultaneously. Another ILP approach separates the HW/SW partitioning and pipelined scheduling problem into two phases. The first phase is focusing on the HW/SW partitioning and mapping problem. Second phase is used to solve the pipelined scheduling problem. The two ILP approaches not only partition and map each computation task of a particular multimedia application onto a component of the heterogeneous multiprocessor architecture, but also schedules and pipelines the execution of these computation tasks while considering communication time. For the first ILP model, the objective is to minimize the total component cost and the number of pipeline stages subject to the throughput constraint. In the second ILP approach, the objective of the first phase and second phase is to minimize the total component cost and the number of pipeline stages subject to the throughput constraint, respectively. Finally, experiments on three real multimedia applications (JPEG Encoder, MP3 Decoder, Wavelet Video Encoder) are used to demonstrate the effectiveness of the proposed approaches.

Due to the rapid advancement of VLSI technology, functions of multimedia systems (e.g. MP3, image processing etc,) become more complex nowadays. Therefore, more complicated system architecture and powerful computing ability are required to attain real-time process. In order to fulfill the requirement of cost and efficiency, multimedia systems usually consist of processors, ASICs and other various components. Diverse real-time functions of multimedia system can be implemented via co-operation of these components. However, these components have the differences in area, efficiency, and cost. Accordingly, it is necessary to establish a useful method and tool to decide better system architecture. ¡@¡@The main objective of the thesis is to develop a decision tool of system architecture. Given the system specification and constraints of a multimedia system, it can quickly decide a good system architecture to satisfy the constraints in accordance with the system specification . Except for partitioning various functions and mapping functions to hardware components, the decision tool must implement scheduling and pipelining to fulfill resource constraints and reach the real-time requirement. A great deal of time and cost for implementing the multimedia system can be reduced by careful scheduling and pipelining. Besides, owing to the pressure of time to market in system development, we propose a series of design flow to speed up the design process. All decision tasks in the flow are finished by automatic or semi-automatic method to reduce the exhaustion of manpower and time. Finally, we make experiments with the proposed tool on several multimedia systems. The results show that the automatic process can conform to constraints which set up by system specifications and ensure the accuracy of the process.

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Benefiting from the constant and significant advancement of wireless communication technologies and networking protocols, Wireless Ad hoc NETwork (WANET) has played a more and more important role in modern communication networks without relying much on existing infrastructures. The past decades have seen numerous applications adopting ad hoc networks for service provisioning. For example, Wireless Sensor Network (WSN) can be widely deployed for environment monitoring and object tracking by utilizing low-cost, low-power and multi-function sensor nodes. To realize such applications, the design and evaluation of communication protocols are of significant importance. Meanwhile, the network performance analysis based on mathematical models is also in great need of development and improvement. This dissertation investigates the above topics from three important and fundamental aspects, including data collection protocol design, protocol modeling and analysis, and physical interference modeling and analysis. The contributions of this dissertation are four-fold. First, this dissertation investigates the synchronization issue in the duty-cycled, pipelined-scheduling data collection of a WSN, based on which a pipelined data collection protocol, called PDC, is proposed. PDC takes into account both the pipelined data collection and the underlying schedule synchronization over duty-cycled radios practically and comprehensively. It integrates all its components in a natural and seamless way to simplify the protocol implementation and to achieve a high energy efficiency and low packet delivery latency. Based on PDC, an Adaptive Data Collection (ADC) protocol is further proposed to achieve dynamic duty-cycling and free addressing, which can improve network heterogeneity, load adaptivity, and energy efficiency. Both PDC and ADC have been implemented in a pioneer open-source operating system for the Internet of Things, and evaluated through a testbed built based on two hardware platforms, as well as through emulations. Second, Linear Sensor Network (LSN) has attracted increasing attention due to the vast requirements on the monitoring and surveillance of a structure or area with a linear topology. Being aware that, for LSN, there is few work on the network modeling and analysis based on a duty-cycled MAC protocol, this dissertation proposes a framework for modeling and analyzing a class of duty-cycled, multi-hop data collection protocols for LSNs. With the model, the dissertation thoroughly investigates the PDC performance in an LSN, considering both saturated and unsaturated scenarios, with and without retransmission. Extensive OPNET simulations have been carried out to validate the accuracy of the model. Third, in the design and modeling of PDC above, the transmission and interference ranges are defined for successful communications between a pair of nodes. It does not consider the cumulative interference from the transmitters which are out of the contention range of a receiver. Since most performance metrics in wireless networks, such as outage probability, link capacity, etc., are nonlinear functions of the distances among communicating, relaying, and interfering nodes, a physical interference model based on distance is definitely needed in quantifying these metrics. Such quantifications eventually involve the Nodal Distance Distribution (NDD) intrinsically depending on network coverage and nodal spatial distribution. By extending a tool in integral geometry and using decomposition and recursion, this dissertation proposes a systematic and algorithmic approach to obtaining the NDD between two nodes which are uniformly distributed at random in an arbitrarily-shaped network. Fourth, with the proposed approach to NDDs, the dissertation presents a physical interference model framework to analyze the cumulative interference and link outage probability for an LSN running the PDC protocol. The framework is further applied to analyze 2D networks, i.e., ad hoc Device-to-Device (D2D) communications underlaying cellular networks, where the cumulative interference and link outage probabilities for both cellular and D2D communications are thoroughly investigated. / Graduate / 0984 / 0544 / tong1987fei@163.com