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Multi-channel speech enhancement algorithms rely on a synchronous sampling of the microphone signals. This, however, cannot always be guaranteed, especially if the sensors are distributed in an environment. To avoid performance degradation the sampling rate offset needs to be estimated and compensated for. In this contribution we extend the recently proposed coherence drift based method in two important...
To utilize asynchronous multichannel recordings with different start and end time of recordings for acoustic scene analysis, we propose a combination method for estimating unrecorded durations and extracting spatial features. Focusing on the fact that amplitude information is relatively robust to the estimation error of the unrecorded durations and the synchronization mismatch of multichannel recordings,...
ForkJoin framework is a widely used parallel programming framework upon which both core concurrency libraries and real-world applications are built. Beneath its simple and user-friendly APIs, ForkJoin is a sophisticated managed parallel runtime unfamiliar to many application programmers: the framework core is a work-stealing scheduler, handles fine-grained tasks, and sustains the pressure from automatic...
This paper represents the heuristic algorithms for optimizing communications in parallel PGAS-programs and minimizes of its execution time. This is achieved by taking into account of hierarchical structure of computer systems while reduction. Developed algorithms are implemented for PGAS-language Cray Chapel.
Purpose of this paper is to model, simulate and control wheeled mobile robotic systems integrated into an assembly mechatronics line for making it reversible, i.e. have the capacity to deal disassembly using mobile platforms equipped with a manipulator. For this purpose, synchronised hybrid Petri nets (SHPN) models will be used to simulate and control an assembly/disassembly (A/D) mechatronics line...
As power level grows, the power converter of wind turbines tends to use parallel-connected smaller converters. The main reason for parallel is that modular design of those smaller converters is relatively mature and cost-effective. However, the parallel of GSCs (Grid-Side Converters) is notorious for its difficulty in control. Bulky and costly filtering capacitor bank is common and LCL resonance problem...
Smart grids rely on the integration of distributed energy resources towards an intelligent and distributed manner to organize the electrical power grid enabled by a bidirectional flow of information to improve reliability and robustness, fault detection and system operation, and plug-and-playability of energy devices. The integration of information and communication technologies (ICT), one of the...
This paper presents a secure image transmission based on a chaotic synchronization. Chaotic systems present unpredictable and complex behavior. These characteristics, together with the dependence on the initial conditions as well as the tolerance of this type of systems, make theme ideal for transmission. In this paper a system of encryption based on chaotic signal is proposed. This system is used...
The 3GPP have standardized the sidelink channels for the long term evolution (LTE) to support device-to-device (D2D) and vehicular-to-vehicular (V2V) communications. This paper investigates the carrier freuqncy offest (CFO) estimation and sidelink ID set detection by using a primary sidelink synchronization signal (PSSS) when a large CFO occurs. We compare the PSSS in the standard and its modified...
Phase-locked loops (PLLs) are doubtless the most popular synchronization technique in the power converters. Almost all proposed PLL structures known in literature are inherently nonlinear and can be linearized as second order linear time invariant system. Nonlinear nature of PLLs degrades their performances, and question arises if there exist an enhanced PLL structure that would have superior performances...
The clock synchronization technologies applied to controlling layer and primary equipment like intelligent switchgear of processing layer in intelligent substation are analyzed in this paper. IEEE1588 message timing mode, which can be accurate to nanosecond, is used as the mode of substation system, in order to fulfill the real-time and accuracy requirements of intelligent switchgears and remote control...
In order to counteract hostile communication based on the advanced Orthogonal Frequency Division Multiplexing (OFDM) technology, an efficient and unrecognizable jamming technique by failing the OFDM cyclic prefix (CP) functionality is developed in the paper. CP is introduced into OFDM systems to prevent interference caused by the multipath fading, as long as it is no shorter than the channel delay...
We present an optimal frame timing estimator for OFDM signals that utilizes both cyclic prefix (CP) and pilot-carrier-aided channel estimation. Combining the periodic nature of the embedded pilot signal information with the correlation present in the cyclic prefix allows improved frame timing estimates relative to use of either one. Following a derivation of the ML estimator, a processor diagram is...
Conventional correlation-based frame synchronization techniques can suffer significant performance degradation over multi-path frequency-selective channels. As a remedy, in this paper we consider joint frame synchronization and channel estimation. This, however, increases the length of the resulting combined channel and its estimation becomes more challenging. On the other hand, since the combined...
In this work, we implement and demonstrate differential amplify-and-forward (DAF) cooperative relaying as a novel diversity technique to combat bit errors and outages common in airborne environments. By using differential modulation and demodulation, we reduce the system complexity by avoiding channel estimation which is often unreliable or computationally costly in dynamic environments with mobile...
This paper provides a methodology to study the PHY layer vulnerability of wireless protocols in hostile radio environments. Our approach is based on testing the vulnerabilities of a system by analyzing the individual subsystems. By targeting an individual subsystem or a combination of subsystems at a time, we can infer the weakest part and revise it to improve the overall system performance. We apply...
Future tactical communications involves high data rate best effort traffic working alongside real-time traffic for time-critical applications with hard deadlines. Unavailable bandwidth and/or untimely responses may lead to undesired or even catastrophic outcomes. Ethernet-based communication systems are one of the major tactical network standards due to the higher bandwidth, better utilization, and...
Chaotic modulation is a strong method of improving communication security. Analog and discrete chaotic systems are presented in actual literature. Due to the expanse of digital communication, discrete-time systems become more efficient and closer to actual technology. The present contribution presents a reliable design method for a discrete-time nonlinear emitter, based on an analogue prototype. The...
In a communication-constrained and adversarial environment, it is an interesting and challenging problem for multiple vehicles to patrol the whole environment by sensing with their limited visibility. Early works based on deterministic paths are predictable to the adversary, and recent non-deterministic works are limited to only a circular environment and require synchronization. So, we propose a...
The rapidly growing design complexity has become a big obstacle and dramatically increased the time required for SystemC simulation. In this case study, we exploit different levels of parallelism, including thread- and data-level parallelism, to accelerate the simulation of a Bitcoin miner model in SystemC. Our experiments are performed on two multi-core processors and one many-core Intel(g) Xeon...
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