scholarly journals Analysis for Joint Delay-Power Tradeoff with Buffer/Channel-Aware and Its FPGA Implementation in Wireless Sensor Networks

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3114
Author(s):  
Joumana Dakkak ◽  
Saleh Eisa ◽  
Hesham M. El-Badawy ◽  
Ahmed Elbakly
Keyword(s):  
Performance Metrics ◽  
Piecewise Linear ◽  
Arrival Rate ◽  
System Parameters ◽  
System A ◽  
Slow Fading ◽  
Optimal Delay ◽  
Goodness Factor ◽  
Widespread Interest ◽  
Tradeoff Curve

In this paper, we aim to investigate the delay-power tradeoff problem which is attracting widespread interest due to its importance in wireless technology. This research has two main objectives. First, to assess the effect of different system parameters on the performance metrics. Second, to provide a solution for this optimization problem. A two-state, slow-fading channel is categorized into good and bad channel states. An adaptive transmission and random data arrivals are considered in our model. Each channel category has its own Markov chain, which is used in modeling the system. A joint Buffer-Aware and Channel-Aware (BACA) problem was introduced. In addition, an enhanced iterative algorithm was introduced for obtaining a sub-optimal delay-power tradeoff. The results show that the tradeoff curve is piecewise linear, convex and decreasing. Furthermore, a channel-aware system was investigated to provide analysis of the effect of system parameters on the delay and power. The obtained results show that the dominant factors that control the system performance are based on the arrival rate and the channel goodness factor. Moreover, a simplified field programable gate array (FPGA) hardware implementation for the channel aware system scheduler is presented. The implementation results show that the consumed power for the proposed scheduler is 98.5 mW and the maximum processing clock speed is 190 MHz.

scholarly journals Resource allocation and task admission control in cloud systems

2021 ◽  
Author(s):  
Haleh Khojasteh
Keyword(s):  
Resource Allocation ◽  
Performance Metrics ◽  
Cloud Model ◽  
Blocking Probability ◽  
Arrival Rate ◽  
Cloud System ◽  
Wide Range ◽  
Priority Scheme ◽  
The Impact ◽  
And Task

The focus of this thesis is solving the problem of resource allocation in cloud datacenter using an Infrastructure-as-a-Service (IaaS) cloud model. We have investigated the behavior of IaaS cloud datacenters through detailed analytical and simulation models that model linear, transitional and saturated operation regimes. We have obtained accurate performance metrics such as task blocking probability, total delay, utilization and energy consumption. Our results show that the offered load does not offer complete characterization of datacenter operation; therefore, in our evaluations, we have considered the impact of task arrival rate and task service time separately. To keep the cloud system in the linear operation regime, we have proposed several dynamic algorithms to control the admission of incoming tasks. In our first solution, task admission is based on task blocking probability and predefined thresholds for task arrival rate. The algorithms in our second solution are based on full rate task acceptance threshold and filtering coefficient. Our results confirm that the proposed task admission mechanisms are capable of maintaining the stability of cloud system under a wide range of input parameter values. Finally, we have developed resource allocation solutions for mobile clouds in which offloading requests from a mobile device can lead to forking of new tasks in on-demand manner. To address this problem, we have proposed two flexible resource allocation mechanisms with different prioritization: one in which forked tasks are given full priority over newly arrived ones, and another in which a threshold is established to control the priority. Our results demonstrate that threshold-based priority scheme presents better system performance than the full priority scheme. Our proposed solution for clouds with mobile users can be also applied in other clouds which their users’ applications fork new tasks.

scholarly journals Resource allocation and task admission control in cloud systems

2021 ◽  
Author(s):  
Haleh Khojasteh
Keyword(s):  
Resource Allocation ◽  
Performance Metrics ◽  
Cloud Model ◽  
Blocking Probability ◽  
Arrival Rate ◽  
Cloud System ◽  
Wide Range ◽  
Priority Scheme ◽  
The Impact ◽  
And Task

The focus of this thesis is solving the problem of resource allocation in cloud datacenter using an Infrastructure-as-a-Service (IaaS) cloud model. We have investigated the behavior of IaaS cloud datacenters through detailed analytical and simulation models that model linear, transitional and saturated operation regimes. We have obtained accurate performance metrics such as task blocking probability, total delay, utilization and energy consumption. Our results show that the offered load does not offer complete characterization of datacenter operation; therefore, in our evaluations, we have considered the impact of task arrival rate and task service time separately. To keep the cloud system in the linear operation regime, we have proposed several dynamic algorithms to control the admission of incoming tasks. In our first solution, task admission is based on task blocking probability and predefined thresholds for task arrival rate. The algorithms in our second solution are based on full rate task acceptance threshold and filtering coefficient. Our results confirm that the proposed task admission mechanisms are capable of maintaining the stability of cloud system under a wide range of input parameter values. Finally, we have developed resource allocation solutions for mobile clouds in which offloading requests from a mobile device can lead to forking of new tasks in on-demand manner. To address this problem, we have proposed two flexible resource allocation mechanisms with different prioritization: one in which forked tasks are given full priority over newly arrived ones, and another in which a threshold is established to control the priority. Our results demonstrate that threshold-based priority scheme presents better system performance than the full priority scheme. Our proposed solution for clouds with mobile users can be also applied in other clouds which their users’ applications fork new tasks.

Dynamics of a Continuous System With Clearance and Motion Limiting Stops

1999 ◽  
Author(s):  
P. Metallidis ◽  
S. Natsiavas
Keyword(s):  
Piecewise Linear ◽  
Research Work ◽  
Continuous System ◽  
Continuous Model ◽  
Equation Of Motion ◽  
Model System ◽  
Periodic Motions ◽  
System Parameters ◽  
Rigid Rods ◽  
The Stability

Abstract The present study generalises previous research work on the dynamics of discrete oscillators with piecewise linear characteristics and investigates the response of a continuous model system with clearance and motion-limiting constraints. More specifically, in the first part of this work, an analysis is presented for determining exact periodic response of a periodically excited deformable rod, whose motion is constrained by a flexible obstacle. This methodology is based on the exact solution form obtained within response intervals where the system parameters remain constant and its behavior is governed by a linear equation of motion. The unknowns of the problem are subsequently determined by imposing an appropriate set of periodicity and matching conditions. The analytical part is complemented by a suitable method for determining the stability properties of the located periodic motions. In the second part of the study, the analysis is applied to several cases in order to investigate the effect of the system parameters on its dynamics. Special emphasis is placed on comparing these results with results obtained for similar but rigid rods. Finally, direct integration of the equation of motion in selected areas reveals the existence of motions, which are more complicated than the periodic motions determined analytically.

Multiple channel queues in heavy traffic. I

1970 ◽  
Vol 2 (01) ◽  
pp. 150-177 ◽  
Author(s):  
Donald L. Iglehart ◽  
Ward Whitt
Keyword(s):  
Heavy Traffic ◽  
Arrival Rate ◽  
Standard System ◽  
Interarrival Time ◽  
Service Rate ◽  
Service Channel ◽  
Multiple Channel ◽  
System A ◽  
The Mean ◽  
Service Channels

The queueing systems considered in this paper consist of r independent arrival channels and s independent service channels, where as usual the arrival and service channels are independent. Arriving customers form a single queue and are served in the order of their arrival without defections. We shall treat two distinct modes of operation for the service channels. In the standard system a waiting customer is assigned to the first available service channel and the servers (servers ≡ service channels) are shut off when they are idle. Thus the classical GI/G/s system is a special case of our standard system. In the modified system a waiting customer is assigned to the service channel that can complete his service first and the servers are not shut off when they are idle. While the modified system is of some interest in its own right, we introduce it primarily as an analytical tool. Let λ i denote the arrival rate (reciprocal of the mean interarrival time) in the ith arrival channel and μ j the service rate (reciprocal of the mean service time) in the jth service channel. Then is the total arrival rate to the system and is the maximum service rate of the system. As a measure of congestion we define the traffic intensity ρ = λ/μ.

scholarly journals A Versatile Coexistence Decision-Making System for Efficient TV Whitespace Sharing among Whitespace Objects

2017 ◽  
Vol 2017 ◽  
pp. 1-20
Author(s):  
M. Asif Raza ◽  
Zafar Iqbal ◽  
Sang-Seon Byun ◽  
Hyunduk Kang ◽  
Heung-No Lee
Keyword(s):  
Decision Making ◽  
Performance Metrics ◽  
Channel Allocation ◽  
System Throughput ◽  
System Quality ◽  
System A ◽  
Throughput Gain ◽  
Decision Making System ◽  
Qos Performance

A coexistence decision-making (CDM) system for efficient TV whitespace (TVWS) sharing among whitespace objects (WSOs) is introduced in this paper. The proposed system is considered versatile in functionality as it jointly takes care of three distinct channel allocation features: (a) optimizing system quality of service (QoS) performance metrics, (b) improving TVWS utility, and (c) satisfying WSO channel demands. Regarding system QoS performance metrics, the TVWS sharing problem is defined as an optimization problem with an aim to maximize the system throughput and minimize unfairness in allocation. Supporting the WSOs channel demands in a TVWS sharing problem is a multifold task which requires elaborate consideration in different aspects of the system performance. To this end, the variations of the SNR of wireless frequency channels which result in variable throughput gain of the WSOs are also taken care of in the proposed CDM system. A fast channel allocation algorithm is then designed that implements the TVWS sharing mechanism in a reasonable amount of time. Additionally, the proposed algorithm improves the TVWS utility by promoting a novel frequency reuse method by exploiting the inter-WSO interference information. Simulation results show the superiority of the proposed algorithm over existing TVWS sharing algorithms.

An Exergy-Based Metric for Evaluating Solar Thermal Absorber Technologies for Gas Heating

2011 ◽  
Author(s):  
Maritza Ruiz ◽  
Van P. Carey
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Loss Factor ◽  
Performance Metrics ◽  
Solar Thermal ◽  
Pumping Power ◽  
Central Receiver ◽  
Gas Heating ◽  
Goodness Factor ◽  
Solar Receiver

The energy conversion effectiveness of the central receiver absorber in concentrating solar thermal power systems is dictated primarily by heat losses, material temperature limits, and pumping power losses. To deliver concentrated solar energy to a gas for process heat applications or gas cycle power generation, there are a wide variety of compact heat exchanger finned surfaces that could be used to enhance the convective transfer of absorbed solar energy to the gas stream flowing through the absorber. In such circumstances, a key design objective for the absorber is to maximize the heat transfer thermodynamic performance while minimizing the pumping power necessary to drive the gas flow through the fin matrix. This paper explores the use of different performance metrics to quantify the combined heat transfer, thermodynamic and pressure loss effectiveness of enhanced fins surfaces used in solar thermal absorbers for gas heating. Previously defined heat exchanger performance metrics, such as the “goodness factor”, are considered, and we develop and explore the use of a new metric, the “loss factor”, for determining the preferred enhanced fin matrix surfaces for concentrated solar absorbers. The loss factor, defined as the normalized exergy loss in the receiver, can be used for nondimensional analysis of the desirable qualities in an optimized solar receiver design. In comparison to previous goodness factor methods, the loss factor metric has the advantage that it quantifies the trade-off between trying to maximize the solar exergy transferred to the gas (high heat transfer rate and delivery at high temperature) and minimizing the pumping exergy loss. In this study, the loss factor is used to compare current solar receiver designs, and designs that use a variety of available plate-finned compact heat transfer surfaces with known Colburn factor (j) and friction factor (f) characteristics. These examples demonstrate how the loss factor metric can be used to design and optimize novel solar central receiver systems, and they indicate fin matrix surfaces that are particularly attractive for this type of application.

scholarly journals Performance Evaluation of Proximity Services and Wi-Fi for Public Safety Mission Critical Voice Application

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Wesley D. Garey ◽  
Yishen Sun ◽  
Richard A. Rouil
Keyword(s):  
Performance Evaluation ◽  
Rural Areas ◽  
Performance Metrics ◽  
Traffic Load ◽  
Access Time ◽  
Light Traffic ◽  
System Parameters ◽  
Proximity Services ◽  
Mission Critical ◽  
Simulation Results

Proximity Services (ProSe) and Wi-Fi are two promising technologies that may provide support for Mission Critical Voice (MCV) applications in remote and rural areas by enabling Device-to-Device (D2D) communication. In this paper, several performance metrics of ProSe and Wi-Fi are evaluated and compared side-by-side under various configurations. The ns-3 simulation results show that ProSe outperforms Wi-Fi in terms of coverage range and access time with a medium traffic load, while Wi-Fi has a shorter access time under a light traffic load. In addition, with various user densities, ProSe offers better coverage range and access time a majority of the time. The evaluation in this paper provides insights to first responders on what to expect with either technology and how to improve the performance by adjusting different system parameters.

Weakly Nonlinear Mass Transfer in an Internally Soluted and Modulated Porous Layer

2020 ◽  
Vol 12 (5) ◽  
pp. 622-631
Author(s):  
Palle Kiran ◽  
S. H. Manjula
Keyword(s):  
Mass Transfer ◽  
Solvability Condition ◽  
Finite Amplitude ◽  
Amplitude Equation ◽  
Third Order ◽  
Weakly Nonlinear ◽  
Weakly Nonlinear Analysis ◽  
System Parameters ◽  
System A ◽  
Rotating Porous Media

The effect of solutal modulation on a rotating porous media is studied. Using solvability condition, the finite amplitude equation is derived at third order of the system. A weakly nonlinear analysis is applied to investigate mass transfer in a porous medium. In this article, the stationary convection is discussed in the presence of solutal Rayleigh number. The amplitude equation (GLE) is solved numerically. Using this GLE the Sherwood number is evaluated in terms of the various system parameters. The effect of individual parameters on mass transport is discussed in detail. It is found that the mass transfer is more for modulated system than un-modulated case. Further, internal solute number Si enhance or diminishes the mass transfer. Finally it is also found that, solutal modulation can be effectively applied in either enhancing or diminishing the mass transfer.

Sensitivity Analysis of the Frequency Response of a Piecewise Linear System in a Frequency Island

2004 ◽  
Vol 10 (2) ◽  
pp. 175-198 ◽  
Author(s):  
A Narimani ◽  
M Farid Golnaraghi ◽  
G Nakhaie Jazar
Keyword(s):  
Frequency Response ◽  
Initial Conditions ◽  
Piecewise Linear ◽  
Excitation Frequency ◽  
Relative Displacement ◽  
System Parameters ◽  
Dynamical Characteristics ◽  
Piecewise Linear System ◽  
Amplitude Vibration ◽  
Large Amplitude Vibration

In this paper, we analyze the frequency response of a piecewise linear suspension system. Dynamical characteristics of the suspension will suddenly change when its relative displacement exceeds a clearance. Piecewise linear characteristics occur, for example, wherever we use stoppers to prevent the system from excessive relative displacement. A modified averaging method is used to find the frequency response of the system to a harmonic base excitation. A frequency island is observed, which corresponds to large amplitude vibration for a certain range of system parameters. The island is an isolated region that cannot be reached by the variation of excitation frequency and depends upon initial conditions. On the frequency island, the isolator amplifies the amplitude of vibration rather than suppressing it. This will be dangerous in applications where stoppers are installed to ensure relative displacement is limited. The ranges of system parameters causing the frequency island are determined. The results obtained by an analytical method are verified using numerical simulation.

Multiple channel queues in heavy traffic. I

1970 ◽  
Vol 2 (1) ◽  
pp. 150-177 ◽  
Author(s):  
Donald L. Iglehart ◽  
Ward Whitt
Keyword(s):  
Heavy Traffic ◽  
Arrival Rate ◽  
Standard System ◽  
Interarrival Time ◽  
Service Rate ◽  
Service Channel ◽  
Multiple Channel ◽  
System A ◽  
The Mean ◽  
Service Channels

The queueing systems considered in this paper consist of r independent arrival channels and s independent service channels, where as usual the arrival and service channels are independent. Arriving customers form a single queue and are served in the order of their arrival without defections. We shall treat two distinct modes of operation for the service channels. In the standard system a waiting customer is assigned to the first available service channel and the servers (servers ≡ service channels) are shut off when they are idle. Thus the classical GI/G/s system is a special case of our standard system. In the modified system a waiting customer is assigned to the service channel that can complete his service first and the servers are not shut off when they are idle. While the modified system is of some interest in its own right, we introduce it primarily as an analytical tool. Let λi denote the arrival rate (reciprocal of the mean interarrival time) in the ith arrival channel and μj the service rate (reciprocal of the mean service time) in the jth service channel. Then is the total arrival rate to the system and is the maximum service rate of the system. As a measure of congestion we define the traffic intensity ρ = λ/μ.

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