Current Issue : April - June Volume : 2016 Issue Number : 2 Articles : 6 Articles
For improving the system performance of mobile Internet, how to provide the Quality of Experience (QoE) guarantee\nis an important factor. First, based on artificial neural network and adaptive cross-layer perceptron, we studied the cloud assisted\nQoE guarantee mechanism. Then, according to the power, we divided the distance and perceptron layers of\nmobile Internet and cloud into three levels. We showed the state information definition of the mobile node on the basis\nof the adaptive adjustment perceptron layers. Thirdly, the perceptron network topology would be updated according to\nthe customer service, which would be updated based on the perceptron learning rule for improving the training practice\nefficiency. The above scheme would guarantee the QoE effectively. The experimental results show that the proposed QoE\nguarantee mechanism has obvious advantages in terms of throughput, efficiency, and reliability....
We introduce a controlled concurrency framework, derived from the Owicki-Gries method, for describing\na hardware interface in detail sufficient to support the modelling and verification of small,\nembedded operating systems (OS�s) whose run-time responsiveness is paramount. Such real-time\nsystems run with interrupts mostly enabled, including during scheduling. That differs from many\nother successfully modelled and verified OS�s that typically reduce the complexity of concurrency by\nrunning on uniprocessor platforms and by switching interrupts off as much as possible.\nOur framework builds on the traditional Owicki-Gries method, for its fine-grained concurrency\nis needed for high-performance system code. We adapt it to support explicit concurrency control,\nby providing a simple, faithful representation of the hardware interface that allows software to control\nthe degree of interleaving between user code, OS code, interrupt handlers and a scheduler that\ncontrols context switching. We then apply this framework to model the interleaving behavior of the\ne Chronos OS, a preemptible real-time OS for embedded micro-controllers. We discuss the accuracy\nand usability of our approach when instantiated to model the eChronos OS. Both our framework and\nthe e Chronos model are formalised in the Isabelle/HOL theorem prover, taking advantage of the high\nlevel of automation in modern reasoning tools....
This paper presents a successful implementation of a novel method to generate digital pulse width modulation (DPWM) signals using 8051 to control DC DC buck converter and assesses experimentally its behaviour for variable supply voltages and step load resistance change. The method for generation of PWM signals to control the DC DC buck converter was developed by studying various methods existed earlier. The experiment was performed using a low cost micro-controller AT89C51RD2 in order to verify the design performance for different conditions. The results were obtained using a self-designed DC DC buck converter, by changing the input voltage and also changing the load resistance and the corresponding waveforms of DPWM signal, output voltage, obtained from simulation are also plotted. The software written for 8051 controller shows very interesting tracking features and is able to keep the output voltage at the desired level even after step load change and input voltage variation. Using the developed algorithm for controller one can set a desired voltage level at the output by doing small change in the program, hence this method also provides flexibility for the DC DC buck converter and can be applied to any DC DC buck converter without doing any changes. It was observed that the developed novel method for DPWM generation yields better results than other methods. Hence it can be used for different application....
In order to solve these problems such as the demand of geographic information service and the short life of the\nembedded system, as well as network collapse, and so on, the embedded mobile crowd service systems based on\nopportunistic geological grid and dynamical split was proposed. Firstly, based on the characteristics of geographical\nspatial information resources and service time series, a mobile geographic crowd service system was established for\nproviding the sensing data with the mobile geographic crowd service model. Then, according to the embedded\nequipment complex data of the geographic crowd service system, and the relationship between the geography\ninformation service object and the user, the embedded system was proposed based on the opportunity geological\ngrid. Finally, the optimization of the geographic crowd system was realized by the dynamic segmentation of the\nopportunity geographic grid. The experiment results of the equipment utilization, the life cycle of the crowd\nnetwork, user satisfaction, and control complexity show that the proposed scheme is more suitable for the\nembedded network geographic information system....
IEEE 802.11 standard is largely used anywhere as a cheap way\nto access internet, but the majority of devices used does not provide a\nstandard way to manage them. Mobile stations competing for access point\nmay causes a general wireless network failure, known as the ââ?¬Å?MAC\nAnomalyââ?¬Â. It is presented here an access point with modified firmware, that\nmonitors wireless conectionsÃ?´s quality and has a programmable capability\nallowing to do network management in a standardized manner, using\nSNMP for example. In this article, embedded Linux ââ?¬Å?OpenWRTââ?¬Â installed\nin a very cheap and reduced size hardware was used. By means of Bourne\nshell script programming, it is possible to collect all important operating\nparameters and data of the access point. From this, its possible to gain\nconsiderable control over it. IEEE 802.11 (Wi-Fi) access point devices are\nrouters, while embedded Linux has routing capabilities. Thus, it is easy to\nimplement traffic policies by means of Bourne shell script programming.\nTraffic shapping is one of the acces pointÃ?´s capabilities successfuly tested\nand demonstrated in this study. MAC anomaly detection in IEEE 802.11\nnetworks can be easily implemented by means of scripts as well. It was\ncollected and plotted network throughput data, becoming possible to\nobserve MAC anomaly in visual charts. A mate mathic model to apply on\nthe collected data of network throughput is under study, aiming to identify\nthe anomaly through calculations. The object of the current study is to\nintegrate everything: Measurements of operation data (network throughput\nin Mbit/s), identification of the MAC anomaly and its immediate\nmitigation. The result was the conception of an integrated device to\nmeasure, identify and mitigate MAC anomaly in a test field and therefore\nrestore network throughput by representing a gain of 42.5216%....
With ubiquitous deployment of sensors and network connectivity, amounts of real-time data for embedded systems are increasing\nrapidly and database capability is required for many embedded systems for systematic management of real-time data. In such\nembedded systems, supporting the timeliness of tasks accessing databases is an important problem. However, recent multi core based\nembedded architectures pose a significant challenge for such data-intensive real-time tasks since the response time of\naccessing data can be significantly affected by potential intercore interferences. In this paper, we propose a novel feedback control\nscheme that supports the timeliness of data-intensive tasks against unpredictable intercore interferences. In particular, we use\nmultiple inputs/multiple outputs (MIMO) control method that exploits multiple control knobs, for example, CPU frequency and\nthe Quality-of-Data (QoD) to handle highly unpredictable workloads in multicore systems. Experimental results, using actual\nimplementation, show that the proposed approach achieves the target Quality-of-Service (QoS) goals, such as task timeliness and\nQuality-of-Data (QoD) while consuming less energy compared to baseline approaches....
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