In this paper, we present an approach to control the locomotion of snake robot with concurrent programming model constructed using threads and semaphores. the multi-thread based concurrent programming model adds the f...
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In this paper, we present an approach to control the locomotion of snake robot with concurrent programming model constructed using threads and semaphores. the multi-thread based concurrent programming model adds the flexibility to design and synchronize the movement of snake robots as compared with microcontroller and mechanical based approaches. We have designed a physical snake robot using LEGO sensors and actuator blocks and the wave motion of the snake robot is generated by multi-thread based concurrent programming under RT-Linux. the different robot movements in a desired direction along with different types of snake movements are achieved using angle sensors.
the UAV (unmanned aerial vehicle) performs various kinds of missions while performing autonomous flight navigation. In order to realize all functionalities of the UAV, the software part becomes a very complex hard rea...
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the UAV (unmanned aerial vehicle) performs various kinds of missions while performing autonomous flight navigation. In order to realize all functionalities of the UAV, the software part becomes a very complex hard real-time system because some hard real-time tasks, soft real-time tasks and non-real-time tasks are concurrently working together under a RTOS. In this paper, a hierarchical architecture for unmanned autonomous helicopter system is proposed that guarantees the real-time performance of hard real-time tasks and the re-configurability of soft realtime or non-real-time tasks under the RT-Linux. this software architecture has four layers: hardware, execution, service agent and remote user interface layer according to the reactiveness level for external events. In addition, the layered separation of concurrent tasks makes different kinds of mission reconfiguration possible in the system. An unmanned autonomous helicopter system was implemented using Kyosho RC Helicopter to test and evaluate the performance of the proposed systems.
the software communications architecture (SCA) is middleware for providing component interfaces and dynamic reconfigurability to software define radio (SDR) modems and it is widely adopted by the SDR forum. Although i...
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the software communications architecture (SCA) is middleware for providing component interfaces and dynamic reconfigurability to software define radio (SDR) modems and it is widely adopted by the SDR forum. Although its main application domains include real-time signal processing, SCA lacks QoS support. We thus propose a QoS-enabled extension of SCA called Q-SCA. Our extended architecture incorporates a new waveform model, extended domain profiles that describe QoS requirements, and a modified application instantiation process that supports both admission control and resource allocation. We show the viability of Q-SCA through full implementation and experiments.
Recent research has expanded to encompass a view of the reconfigurable logic where a resource is shared among multiple applications or users. Run-time reconfiguration is a method of computing by dynamically changing h...
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ISBN:
(纸本)9780780394292
Recent research has expanded to encompass a view of the reconfigurable logic where a resource is shared among multiple applications or users. Run-time reconfiguration is a method of computing by dynamically changing hardware configurations from phase to phase of a computation. In real-time multi-tasking system design, task deadlines play an important role as systems not only need to support sharing of the resources in space, but also need to guarantee execution of the tasks. At the operating system level, sharing logic gates, wires, and I/O pins among multiple tasks needs to be managed: and, from the high level standpoint, access to the resources needs to be scheduled according to task deadlines. this paper describes a novel approach, based on hardware/sofware co-design modeling to task allocation for scheduling tasks on a shared hardware tinder run-time constraints. the proposed task allocation technique has been implemented on a reconfigurable computing platform from Xilinx (R) that employs vs Virtex-II pro (TM) FPGA and embedded power PC Core.
Fixed-priority with preemption threshold (FPPT) is an important form of real-time scheduling algorithm, which fills the gap between fixed-priority preemptive (FPP) and fixed-priority non-preemptive (FPNP). However, th...
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Fixed-priority with preemption threshold (FPPT) is an important form of real-time scheduling algorithm, which fills the gap between fixed-priority preemptive (FPP) and fixed-priority non-preemptive (FPNP). However, this scheduling scheme together withthe requirements of fault tolerance makes the prediction of a real-time system's behaviors more difficult than traditional scheduling scheme. the major contribution of this work is twofold. First, we present an appropriate schedulability analysis, based on response time analysis, for supporting fault-tolerant FPPT scheduling in hard real-timesystems. the error-recovery techniques are considered to be used to carry out fault tolerance. Second, we propose the optimal priority assignment algorithm which can be used, together withthe schedulability analysis, to improve system fault resilience.
the problem of guaranteeing "meet row n in m" weakly hard real-time constraint is addressed in this paper. the paper first analyzes characters of /spl mu/-pattern and gives out the definition of "unsati...
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the problem of guaranteeing "meet row n in m" weakly hard real-time constraint is addressed in this paper. the paper first analyzes characters of /spl mu/-pattern and gives out the definition of "unsatisfied /spl mu/-pattern". then, it enumerates and proves several properties of unsatisfied /spl mu/-pattern. According to the properties, length of unsatisfied /spl mu/-pattern can indicate whether the /spl mu/-pattern satisfies the meet row constraint, therefore, a scheduling algorithm named meet row algorithm is presented based on the properties. Meet row algorithm tries to find out the probabilities of tasks breaking constraints and increase task's priority in advance. Simulation results show that meet row algorithm is better than other scheduling algorithms for meet row constraints and can largely decrease the worst-case computation time of real-time tasks.
Withthe advent of miniaturized sensing technology, it has become possible to envision smart structures containing millions of sensors embedded in concrete for autonomously detecting and locating incipient damage. Whe...
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Withthe advent of miniaturized sensing technology, it has become possible to envision smart structures containing millions of sensors embedded in concrete for autonomously detecting and locating incipient damage. Where are we today in our march towards this vision of autonomous structural health monitoring (SHM) using networked embedded sensing? In this paper, we summarize some of the systems we have developed towards this vision. Wisden is a wireless sensor network that allows continuous monitoring of structures and NetSHM is a programmable system that allows civil engineers to implement and deploy SHM techniques without having to understand the intricacies of wireless sensor networking. We highlight our experiences in developing these systems, and discuss the implications of our experiences on the achievability of the overall vision.
Wireless sensor network (WSN) has many promising applications. One of the most challenging technical issues for sensor network design is to enable ultra low power consumption communication. In this paper we propose a ...
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Wireless sensor network (WSN) has many promising applications. One of the most challenging technical issues for sensor network design is to enable ultra low power consumption communication. In this paper we propose a packet compression mechanism, namely EasiPC, as a new power management technique for WSN withthis mechanism, the lengths of data packets are shortened significantly due to the effective reduction of redundant information. As a consequence the energy required for transporting packets is saved too. Experiments carried out on WSN platform developed in-house show that this packet compression mechanism is both feasible and effective. Additional benefits introduced by this packet compression mechanism include reduced transmission delays, reduced channel accessing collisions, as well as enhanced channel utilization.
Although simultaneous multithreading (SMT) has been shown being an efficient technique to improve processor performance, little work has been done on real-time SMT scheduling. the objective of this paper is to explore...
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Although simultaneous multithreading (SMT) has been shown being an efficient technique to improve processor performance, little work has been done on real-time SMT scheduling. the objective of this paper is to explore realtime SMT scheduling for independent periodic task sets with schedulability guarantees. We propose emulation-based scheduling algorithms with and without task migration to emulate an adjustable SMT processor over a non-adjustable SMT processor. the schedulability tests for the proposed scheduling algorithms are presented. An approximation bound on the average number of tasks running in parallel is also shown. the performance of the proposed algorithms was evaluated by a series of simulation experiments.
Most of the flash storage systems reclaim the space occupied by invalid data only when the available free space is low and a data writing request is being processed thereby may intermittently increase the time of carr...
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Most of the flash storage systems reclaim the space occupied by invalid data only when the available free space is low and a data writing request is being processed thereby may intermittently increase the time of carrying out a writing operation and decrease the system performance. For real-timeapplications, such passive space recycling not only results in tasks suffering long blocking time but also imposes great impact on the predictability of their timing behaviors. this paper presents an active mechanism to recycle invalidated space in flash storage system which, by periodically launching tasks to reclaim data space containing invalid data, can reduce the blocking incurred from space recycling as well as provide a more analyzable recycling operation. the active space recycling mechanism can work well withthe wear-leveling mechanism commonly required in flash storage management. In addition, the implementation requires no changes of its host file system. Simulation results show that the proposed space recycling mechanism has significant improvement on the worst case timing behaviors of write operations.
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