Current Issue : April - June Volume : 2018 Issue Number : 2 Articles : 5 Articles
The proliferation of low-cost embedded system platforms has allowed the creation of large communities of developers,\nas well as the development of new advanced applications. Even though some of these applications can be of\nindustrial relevance, their immediate application to real products is not straightforward since most of them require a\ncomplete and expensive hardware redesign of the considered embedded solution. To speed up the technological\ntransfer of custom embedded solutions while overtaking the limits imposed by a complete hardware redesign, the\narticle presents AMBER, an innovative embedded platform leveraging on a design based on System-on-Modules (SOM)\nand Extender modules. AMBER decouples the processing part of the system, which is fully contained on the SOM,\nfrom the peripherals, which are contained on the main board and Extender modules. This allows a smooth industrialoriented\nredesign of the embedded solution. In the article, AMBER is first presented starting from its philosophy and\ndesign choices while highlighting its main features. Then, an application of AMBER as an enhanced gateway to be\nused in the Industrial Internet of Things (IIoT) scenario is reported by considering a monitoring and actuation use case.\nThe IIoT-oriented AMBER solution is hardware and software configured to support real-time communications with\nactuators compliant with the Powerlink standard, as well as to interact with sensors compliant with Bluetooth Low\nEnergy. Performance results show the effectiveness of the proposed solution in the selected industrial scenario while\npromoting a fast and immediate transfer in new embedded products targeted to IIoT applications...
Today, wireless devices generally feature multiple radio access technologies (LTE, WIFI, WIMAX, ...) to handle a rich\nvariety of standards or technologies.These devices should be intelligent and autonomous enough in order to either\nreach a given level of performance or automatically select the best available wireless technology according to\nstandards availability. On the hardware side, system on chip (SoC) devices integrate processors and field-programmable\ngate array (FPGA) logic fabrics on the same chip with fast inter-connection. This allows designing software/hardware\nsystems and implementing new techniques and methodologies that greatly improve the performance of\ncommunication systems. In these devices, Dynamic partial reconfiguration (DPR) constitutes a well-known technique\nfor reconfiguring only a specific area within the FPGA while other parts continue to operate independently. To evaluate\nwhen it is advantageous to perform DPR, adaptive techniques have been proposed. They consist in reconfiguring parts\nof the system automatically according to specific parameters. In this paper, an intelligent wireless communication\nsystem aiming at implementing an adaptive OFDM-based transmitter and performing a vertical handover in\nheterogeneous networks is presented. An unified physical layer for WIFI-WIMAX networks is also proposed. The\nsystem was implemented and tested on a ZedBoard which features a Xilinx Zynq-7000-SoC. The performance of the\nsystem is described, and simulation results are presented in order to validate the proposed architecture....
In the domain of wireless digital communication, floating-point arithmetic is generally used to conduct performance\nevaluation studies of algorithms. This is typically limited to theoretical performance evaluation in terms of\ncommunication quality and error rates. For a practical implementation perspective, using fixed-point arithmetic\ninstead of floating-point reduces significantly implementation costs in terms of area occupation and energy\nconsumption. However, this implies a complex conversion process, particularly if the considered algorithm includes\ncomplex arithmetic operations with high accuracy requirements and if the target system presents many configuration\nparameters. In this context, the purpose of the paper is to present an efficient quantization and fixed-point\nrepresentation for turbo-detection and turbo-demapping. The impact of floating-to-fixed-point conversion is\nillustrated upon the error-rate performance of the receiver for different system configurations. Only a slight\ndegradation in the error-rate performance of the receiver is observed when implementing the detector and demapper\nmodules which utilize the devised quantization and fixed-point arithmetic rather than floating-point arithmetic...
State-based schedules use a time division multiple access (TDMA) mechanism that supports executing conditional\nsemantics and making on-the-fly decisions at runtime in each communication cycle. Until now, state-based schedules\nare unable to tolerate transient faults due to the assumption that stations make the on-the-fly decision on which\nmessage to execute next. Stations may make a faulty decision at run time in an unreliable communication\nenvironment such as wireless medium due to the presence of transient faults. This faulty decision causes state\ninconsistency among the stations in the system.\nIn this work, we extend state-based schedules to tolerate faulty decisions in environments where transient faults can\noccur at the communication layer. Our proposed approach generates fault-tolerant state-based schedules using an\ninteger linear programming optimization model after reducing the possibility of state inconsistency through using a\nclock and a sampling rate synchronization mechanism. The optimization model maximizes the use of time slots to\nplace checkpoints for fault tolerance and resolving state inconsistency....
With the increasingly common use of industrial automation for mass production, there are\nmany computer numerical control (CNC) machine tools that require the collection of data from\nintelligent sensors in order to analyze their processing quality. In general, for high speed rotating\nmachines, an accelerometer can be attached on the spindle to collect the data from the detected\nvibration of the CNC. However, due to their cost, accelerometers have not been widely adopted\nfor use with typical CNC machine tools. This study sought to develop an embedded miniature\nMEMS microphone array system (Radius 5.25 cm, 8 channels) to discover the vibration source of\nthe CNC from spatial phase array processing. The proposed method utilizes voice activity detection\n(VAD) to distinguish between the presence and absence of abnormal noise in the pre-stage, and\nutilizes the traditional direction of arrival method (DOA) via multiple signal classification (MUSIC)\nto isolate the spatial orientation of the noise source in post-processing. In the numerical simulation,\nthe non-interfering noise source location is calibrated in the anechoic chamber, and is tested with\nreal milling processing in the milling machine. As this results in a high background noise level,\nthe vibration sound source is more accurate in the presented energy gradation graphs as compared to\nthe traditional MUSIC method....
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