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This paper proposes the algorithms for optimization of Remote Core Locking (RCL) synchronization method in multithreaded programs. The algorithm of initialization of RCL-locks and the algorithms for threads affinity optimization are developed. The algorithms consider the structures of hierarchical computer systems and non-uniform memory access (NUMA) to minimize execution time of RCL-programs. The...
State-machine replication (SMR) is a fundamental technique to implement fault-tolerant services. Recently, various works have aimed at enhancing the scalability of SMR by exploiting partial replication techniques. By sharding the state machine across disjoint partitions, and replicating each partition over independent groups of processes, a Partially Replicated State Machine (PRSM) can process operations...
We consider a collision channel model without feedback based on a time-slotted communication channel shared by K users. In this model, packets transmitted in the same time slot collide with each other and are unrecoverable. Each user accesses the channel according to an internal periodical pattern called protocol sequence. Due to the lack of feedback, users cannot synchronize their protocol sequences,...
The concept of complex event processing (CEP) and complex-event-aware service have been extensively studied to retrieve relevant information from massive amount of realtime streaming events. In mobile environment, the Mobilityaware CEP (MCEP) system was proposed to address the issue of synchronization problem between different query ranges and MCEP operators. We noticed that MCEP systems lack the...
In distributed transmit beamforming, two, or more, spatially separated communications nodes act as elements of an antenna array to beamform common data to a destination node. Spatially separated cooperating nodes synchronize their carrier frequencies and control their transmission phases so that at the destination node the received signals combine constructively. An important example is cooperative...
We present Timestamp Order Preserving (TOP), a replicated state machine (RSM) protocol that exploits the synchrony of networks to provide high performance. TOP uses physical timestamp of synchronized clock as a consistent total order to achieve consensus. It keeps estimating the bounds of network latency and offset of synchronized clock to deduce the commit time for each operation. It adopts speculative...
In this work, we mainly consider the synchronization problem of hybrid transmit-only nodes for slight modified IEEE 802.15.4 wireless sensor networks, which is called TRO 802.15.4. However, we should let the IEEE 802.15.4 networks to fit transmission cycle of transmit-only nodes in order to achieve the synchronization. The adaptive beacon interval shifting and resizing (ABISR) algorithm is then proposed...
This paper presents a family of FIFOs for clock-domain crossings. These designs are distinguished by an interleaved architecture for the control and data-paths. This approach eliminates most of the throughput bottlenecks in the FIFO design, allowing operation at well over 1GHz in a 65nm process using a standard ASIC design flow. Furthermore, these designs are low-latency: the fall-through time for...
When different technologies use the same frequency bands in close proximity, the resulting interference typically results in performance degradation. Coexistence methods exist, but these are often technology specific and require technology specific interference detection methods. To remove the root cause of the performance degradation, devices should be able to negotiate medium access even when using...
In this paper we propose the Slot Reservation Announcement (SRA) access scheme to minimize the occurrence of channel-access collisions in infrastructure IEEE 802.11 networks under emergency and crowded scenarios. SRA is based on slot reservation in lieu of a randomized backoff approach to increase the channel-access success ratio. The proposed scheme rids IEEE 802.11-like access networks of throughput...
With the spreading of multi-core architectures, operating systems and applications are becoming increasingly more concurrent and their scalability is often limited by the primitives used to synchronize the different hardware threads. In this paper, we address the problem of how to optimize the throughput of a system with multiple producer and consumer threads. Such applications typically synchronize...
Pipe-and-Filter (P&F) is a well-known and often used architectural style. However, to the best of our knowledge, there is no P&F framework which can model and execute generic P&F architectures. For example, the frameworks Fastflow, StreamIt, and Spark do not support multiple input and output streams per filter and thus cannot model branches. Other frameworks focus on very specific use...
This paper describes the design and implementation of a simple chaotic communication system on FPGA using Rössler's chaotic system of equations. The system was simulated to insure proper operation, before being implemented on hardware using VHDL. Throughput of 2850 Mbps was obtained. The implementation results on Xilinx Zynq-7000 series FPGA show the feasibility of using digital hardware to implement...
The FSM-SADF model of computation is especially suitable for analysing real-time applications with input-dependent behaviour such as different modes, variable execution times and scalable parallelism. Although FSM-SADF specifies which scenario transitions are possible, it does not specify how and when they are decided at runtime. Multiple actors of a scenario, e.g. video stream header parsing, may...
Time is a foundational aspect of Cyber-Physical Systems (CPS). Correct time and timing of system events are critical to optimized responsiveness to the environment, in terms of timeliness, accuracy, and precision in the knowledge, measurement, prediction, and control of CPS behavior. However, both the specification and verification of timing requirements of the CPS are typically done in an ad-hoc...
Recently, mobile broadcast services such as DMB, multimedia streaming services and IPTV, caused rapid increase of multimedia services sent over the Internet. It is important to define, measure and evaluate the elements related to the quality of providing the services over the Internet. In this paper, we propose multimedia quality measurement model that evaluates the quality of multimedia from consumers...
Unlimited voice services no longer command premium pricing, but are viewed as “table stakes” in a broader service offering that must now include multimedia (voice, data, video) communications with a mobility component. As a result of this shift, many service providers are trying to adopt, Long Term Evolution (LTE) network strategy to deliver this multimedia experience to their subscribers [1]. Today,...
Traffic safety and efficiency are the most important motivations for the rapid development of vehicular ad hoc network (VANET) technology. VANET is considered to provide the unified platform and solutions for the intelligent transportation system (ITS). In this paper, a novel method named spectrum penetration is proposed to improve the throughput of multi-channel MAC for VANET. Meanwhile, it can overcome...
In this work, we consider the problem of distributed link scheduling for D2D communications without a centralized controller. Our design goal is to maximize a chosen global objective function. For example, maximizing the long-term proportional fair throughput amongst distributed links can be such a goal. In principle, each link evaluates whether its rate increase by raising its transmit power is sufficient...
The speedup is usually limited by two main laws in high-performance computing, that is, the Amdahl's and Gustafson's laws. However, the speedup sometimes can reach far beyond the limited linear speedup, known as superlinear speedup, which means that the speedup is greater than the number of processors that are used. Although the superlinear speedup is not a new concept and many authors have already...
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