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We present a new fast polling algorithm (FPA) in a wireless mesh network (WMN) for Narrowband Internet of Things systems using multi-hop WMNs. We focus on wireless networks with stationary IoT remote telemetry units (IoT RTU), suc...
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We present a new fast polling algorithm (FPA) in a wireless mesh network (WMN) for Narrowband Internet of Things systems using multi-hop WMNs. We focus on wireless networks with stationary IoT remote telemetry units (IoT RTU), such as wireless network monitoring. The goal of the new FPA is to minimize the time required for supervisory control and data acquisition center to poll all RTUs one by one and to receive their responses using random network coding. We study the performance of the proposed FPA by applying it in a WMN composing of 3 and 50 RTUs with a sub-carrier spacing of 6.25 kHz, 12.5 kHz, 25 kHz, and 50 kHz. This paper also provides a comparative study of existing polling cycle mechanisms; we find that our FPA significantly outperforms previously proposed polling-cycle mechanisms with improvements typically exceeding 70%.
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We consider cyclic polling models with gated or globally gated service, and study the transient behavior of all cycle lengths. Our aim is to analyze the dependency structure between the different cycles, as this is an intrinsic pr...
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We consider cyclic polling models with gated or globally gated service, and study the transient behavior of all cycle lengths. Our aim is to analyze the dependency structure between the different cycles, as this is an intrinsic property making polling models challenging to analyze. Moreover, the cycle structure is related to the output of a polling model and the current analysis may be useful to study networks of polling models. In addition, transient performance is of great interest in systems where disruptions or breakdowns may occur, leading to excessive cycle lengths. The time to recover from such events is a primary performance measure. For the analysis we assume that the distribution of the first cycle (globally gated) or N residence times (gated), where N is the number of queues, is known and that the arrivals are Poisson. The joint Laplace-Stieltjes transform (LST) of all x subsequent cycles (globally gated) or all x > N subsequent residence times (gated) is expressed in terms of the 1ST of the first cycle. From this joint 1ST, we derive first and second moments and correlation coefficients between different cycles. Finally, a heavy-tailed first cycle length or the heavy-traffic regime provides additional insights into the time-dependent behavior. (C) 2015 Elsevier B.V. All rights reserved.
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Wireless sensor network (WSN) in the hybrid optical and WSN (HOWSN) utilizes full advantages of broadband access facility. Passive optical network (PON) as the backbone of HOWSN ensures energy efficiency and meets the higher bandw...
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Wireless sensor network (WSN) in the hybrid optical and WSN (HOWSN) utilizes full advantages of broadband access facility. Passive optical network (PON) as the backbone of HOWSN ensures energy efficiency and meets the higher bandwidth demands. However, in the conventional HOWSNs, the sensor nodes of WSN stay in active state for 100% time, i.e., 100% duty cycle, with the optical access networks cause huge amount of energy wastage. This paper presents a new delay and energy efficient (DEE) dynamic bandwidth allocation (DBA) algorithm with multi-threaded polling approach for the optical network units of the HOWSNs. In the proposed scheme, to conserve the energy consumption of HOWSNs, the optical network units (ONUs) connected to the gateway nodes of WSN use 10% duty cycle, whereas the ONUs connected to the data network use 100% duty cycle. The performance of the proposed DEE scheme is evaluated by numerical simulations and compared those to the existing adaptive limited DBA (ALDBA) schemes, i.e., ALDBA1, ALDBA2 and ALDBAM, of HOWSNs. The simulation results prove that the proposed DEE scheme provides up to 32% and 38% more energy savings with lower end-to-end packet delay compared to the existing ALDBA1, ALDBA2 and ALDBAM schemes of HOWSNs, respectively.
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This paper investigates the presence of political budget cycles (PBCs) in the European Union using data from all 27 member states over the period 1997-2008, and explores their variability across countries and over time. Three basi...
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This paper investigates the presence of political budget cycles (PBCs) in the European Union using data from all 27 member states over the period 1997-2008, and explores their variability across countries and over time. Three basic results emerge: First, incumbent governments across the EU tend to engineer PBCs in order to enhance their re-election prospects. Second, PBCs are much larger and statistically more robust in the Eurozone countries than in the countries that have not yet adopted the euro. Third, the degree to which governments manipulate fiscal policy is negatively correlated with non-economic voting and positively correlated with electoral competitiveness.
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This event study uses economic forecasts and opinion polls to measure the response of expectations to election surprise. Use of forecast data complements older work on partisan cycles by allowing a tighter link between election an...
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This event study uses economic forecasts and opinion polls to measure the response of expectations to election surprise. Use of forecast data complements older work on partisan cycles by allowing a tighter link between election and response thereby mitigating concerns of endogeneity and omitted variables. I find that forecasters respond swiftly and significantly to election surprise. I further argue that the response ought to vary across countries with different institutional foundations. In support, I find that there exist three distinct patterns in forecasters' responses to partisan surprise corresponding to Hall and Soskice's three varieties of capitalism.
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Motivated by emerging Internet-of-Things (IoT) applications and smart building environments, we analyze the performance of large-scale symmetric polling systems where the number of queues grows large. We consider a scenario in whi...
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Motivated by emerging Internet-of-Things (IoT) applications and smart building environments, we analyze the performance of large-scale symmetric polling systems where the number of queues grows large. We consider a scenario in which the total arrival rate is kept fixed and the individual switch-over time and service time distributions remain the same. This asymptotic regime leads to cycles of infinite length and queue lengths with non-trivial distributions. We show that for most traditional service policies the scaled cycle times converge to a deterministic value in the limit, which in turn implies that the queue lengths at the various nodes become asymptotically independent. Using these insights, we find that the behavior of individual queues simplifies to that of a discrete time bulk service queue in the limit, so that the marginal queue length and waiting-time distributions become considerably easier to analyze. Additionally, we propose a new flexible k-limited service discipline aimed at striking a good balance between short mean queue lengths and predictable cycle times for deadline-critical applications. (C) 2019 Elsevier B.V. All rights reserved.
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This paper focuses on the mathematical analysis of order flow times in parts-to-picker warehouses with remotely located order-picking workstations. To this end, a polling system with a new type of arrival process and service disci...
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This paper focuses on the mathematical analysis of order flow times in parts-to-picker warehouses with remotely located order-picking workstations. To this end, a polling system with a new type of arrival process and service discipline is introduced as a model for an order-picking workstation. Stochastic bounds are deduced for the cycle time, which corresponds to the order flow time. These bounds are shown to be adequate and aid in setting targets for the throughput of the storage area. The paper thus complements existing literature, which mainly focuses on optimizing the operations in the storage area. (C) 2016 Elsevier B.V. All rights reserved.
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The Interleaved Polling with Adapted Cycle Times (IPACT) algorithm for dynamic bandwidth allocation proposed for Ethernet Passive Optical Networks (EPONs) has been deeply analysed in the literature under Poisson traffic. However, ...
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The Interleaved Polling with Adapted Cycle Times (IPACT) algorithm for dynamic bandwidth allocation proposed for Ethernet Passive Optical Networks (EPONs) has been deeply analysed in the literature under Poisson traffic. However, the case when ONUs suddenly offer bursty traffic in the upstream channel of a PON has not been considered in such detail. This paper studies the performance behaviour of the upstream channel of EPONs employing IPACT with the gated-service disciple, under Poisson traffic together with sudden bursts. We show that one burst arrival produces a peak in the average transmission window of every ONU, lasting its effects for several cycle times, depending on the burst size and the average network load. Such a burst has a direct impact on the delay experienced by the packets of other ONUs. This is mathematically modelled using a modification of the formerly studied M/G/1 queue with vacations and validated with simulation.
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In this paper, a dynamic bandwidth allocation (DBA) algorithm based on differentiated service cycle (DSC) in multiple service (multi-service) hybrid Virtual Passive Optical Network (VPON) is proposed. The DSC algorithm introduces ...
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In this paper, a dynamic bandwidth allocation (DBA) algorithm based on differentiated service cycle (DSC) in multiple service (multi-service) hybrid Virtual Passive Optical Network (VPON) is proposed. The DSC algorithm introduces neural network prediction and improves the polling mechanism between Optical Network Unit (ONU) and Optical Line Terminal (OLT). DSC can be applied to multi-service VPON scenarios. By introducing neural network, the problem that traditional prediction methods can only predict one polling cycle service traffic will be solved. By establishing the separation mechanism of report cycle and prediction cycle, the idle time in multi-wavelength VPON is eliminated, and the bandwidth consumption caused by a large number of REPORT messages is reduced. By proposing differentiated service cycle polling mechanism, the transmission delay of high priority service traffic caused by the simultaneous interpreting of multiple services in offline DBA algorithm can be reduced. Finally, by the simulation and analysis, the effectiveness of the proposed model is demonstrated.
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The energy constraint is still a common issue for the practical application of wireless sensors, since they are usually powered by batteries which limit their lifetime. In this paper, a practical compound energy efficiency strateg...
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The energy constraint is still a common issue for the practical application of wireless sensors, since they are usually powered by batteries which limit their lifetime. In this paper, a practical compound energy efficiency strategy is proposed and realized in the implementation of a real time wireless sensor platform. The platform is intended for wireless structural monitoring applications and consists of three parts, wireless sensing unit, base station and data acquisition and configuration software running in a computer within the Matlab environment. The high energy efficiency of the wireless sensor platform is achieved by a proposed adaptive radio transmission power control algorithm, and some straightforward methods, including adopting low power ICs and high efficient power management circuits, low duty cycle radio polling and switching off radio between two adjacent data packets' transmission. The adaptive transmission power control algorithm is based on the statistical average of the path loss estimations using a moving average filter. The algorithm is implemented in the wireless node and relies on the received signal strength feedback piggybacked in the ACK packet from the base station node to estimate the path loss. Therefore, it does not need any control packet overheads. Several experiments are carried out to investigate the link quality of radio channels, validate and evaluate the proposed adaptive transmission power control algorithm, including static and dynamic experiments.
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