The problem of allocation and release of subcubes from a hypercube with node failures is addressed. Two algorithms are presented, both based on the Buddy allocation scheme for memory management which is also used by t...
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In this paper, we apply the load sharing (LS) mechanism proposed in [1, 2] to HARTS, an experimental distributed realtime system [3] currently being built at the real-timecomputinglaboratory of the University of Mic...
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This paper describes an embedding of Triple Modular Redundancy (TMR) into a binary hypercube. The goal is to improve fault tolerance by masking any single-point faults. Each module of an application task is triplicate...
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ISBN:
(纸本)0897912780
This paper describes an embedding of Triple Modular Redundancy (TMR) into a binary hypercube. The goal is to improve fault tolerance by masking any single-point faults. Each module of an application task is triplicated and executed in parallel on three nodes of a 2-dimensional subcube (Q2) of the hypercube. Each of these nodes also executes a voter process. The remaining node is used for message passing only. All outputs from the triplicated modules are voted on, and the voting results are transmitted to the appropriate destination. Thus, all interunit messages are also triplicated. We propose an embedding of TMR into a hypercube which can be implemented in a manner transparent to the application program. Subcubes are allocated so that the address space for the TMR units is also a hypercube. Hence, the subcube allocation and intermodule communication schemes are defined to be analogous to the schemes used in the nonre-dundant system. The embedded system is proven to mask all single-point faults.
As a superior multicarrier technique utilizing chirp signals for high-mobility communications, affine frequency division multiplexing (AFDM) is envisioned to be a promising candidate for sixth-generation (6G) wireless...
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We describe an end-to-end tool-chain for model-based design and analysis of component-based embedded real-time software. All aspects of an embedded real-time system are captured in domain-specific models, including so...
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In cognitive radio networks (CRNs), spectrum sensing is key to opportunistic spectrum access while preventing any unacceptable interference to primary users' communications. Although cognitive radios function as s...
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ISBN:
(纸本)9781605587387
In cognitive radio networks (CRNs), spectrum sensing is key to opportunistic spectrum access while preventing any unacceptable interference to primary users' communications. Although cognitive radios function as spectrum sensors and move around, most, if not all, of existing approaches assume stationary spectrum sensors, thus providing inaccurate sensing results. As part of our effort to solve/alleviate this problem, we consider the impact of sensor mobility on spectrum sensing performance in a joint optimization framework for sensor cooperation and sensing scheduling. We show that sensor mobility increases spatio-temporal diversity in received primary signal strengths, and thus, improves the sensing performance. This is intuitively plausible, but have not been tested previously. Based on this observation, we propose a sensing strategy that minimizes the sensing overhead by finding an optimal combination of the number of sensors to cooperate and the number of times spectrum sensing must be scheduled. This result provides a useful insight to understand the spectrum sensing and its coupling with sensor mobility. Copyright 2009 ACM.
An effective failure-detection scheme is essential for reliable communication services. Most computer network rely on behavior-based detection schemes: each node uses heartbeats to detect the failure of its neighbor n...
In hard real-time systems, the problem of scheduling periodic tasks to meet their deadlines has been studied extensively, but scheduling aperiodic tasks has been addressed far less, due mainly to their uncertain arriv...
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We address the problem of rapidly discovering spectrum opportunities for seamless service provisioning for secondary users (SUs) in cognitive radio networks (CRNs). Specifically, we propose an efficient sensing-sequen...
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