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.

scholarly journals Performance Evaluation of GAA Nanosheet FET with Varied Geometrical and Process Parameters

2021 ◽  
Author(s):  
Aruna Kumari Neelam ◽  
Prithvi P
Keyword(s):  
Temperature Compensation ◽  
High Performance ◽  
Field Effect Transistor ◽  
Performance Metrics ◽  
Electrical Characteristics ◽  
Transfer Characteristics ◽  
Wide Range ◽  
Effect Transistor ◽  
20 Nm ◽  
The Impact

Abstract Nanosheet Field Effect Transistor (NSFET) is a viable contender for future scaling in sub-7-nm technology. This paper provides insights into the variations of DC FOMs for different geometrical configurations of the NSFET. In this script, DC performance of 3D GAA NSFET is analyzed by varying the width, thickness of the device. Moreover, the gate length is scaled from 20 nm to 5 nm to check for the device suitability in logic applications. The thickness and width of each nanosheet are varied in the range of 5 to 9 nm, and 10 to 50 nm respectively to analyse the performance dependency on the geometry of the device. The impact of geometry of NSFET on various DC performance metrics like transfer characteristics, sub-threshold swing (SS), on current (ION), off current (IOFF), switching ratio (ION/IOFF), threshold voltage (Vth) and drain induced barrier lowering (DIBL) are studied. On top of that, the device’s electrical characteristics are analyzed for a wide range of temperatures from -43oC to 127oC to identify the temperature compensation point and is observed at VGS = 0.55 V and ID = 3.86 × 10−6 A. Furthermore, the important process parameter, work function variations on transfer characteristics of the device is analyzed. Moreover, the analyses tell that, for sub -7 nm, the NSFET is a potential device for high performance and good logic applications.

scholarly journals The response of precipitation to aerosol through riming and melting in deep convective clouds

2010 ◽  
Vol 10 (11) ◽  
pp. 29007-29050
Author(s):  
Z. Cui ◽  
S. Davies ◽  
K. S. Carslaw ◽  
A. M. Blyth
Keyword(s):  
Cloud Model ◽  
Cloud Microphysics ◽  
Mixed Phase ◽  
Cloud Base ◽  
Spatial And Temporal Variability ◽  
Convective Clouds ◽  
Ice Particles ◽  
Wide Range ◽  
Deep Convective Clouds ◽  
The Impact

Abstract. We have used a 2-D axisymmetric, non-hydrostatic, bin-resolved cloud model to examine the impact of aerosol changes on the development of mixed-phase convective clouds. We have simulated convective clouds from four different sites (three continental and one tropical marine) with a wide range of realistic aerosol loadings and initial thermodynamic conditions (a total of 93 different clouds). It is found that the accumulated precipitation responds very differently to changing aerosol in the marine and continental environments. For the continental clouds, the scaled total precipitation reaches a maximum for aerosol that produce drop numbers at cloud base between 180–430 cm−3 when other conditions are the same. In contrast, all the tropical marine clouds show an increase in accumulated precipitation and deeper convection with increasing aerosol loading. For continental clouds, drops are rapidly depleted by ice particles shortly after the onset of precipitation. The precipitation is dominantly produced by melting ice particles. The riming rate increases with aerosol when the loading is very low, and decreases when the loading is high. Peak precipitation intensities tend to increase with aerosol up to drop concentrations (at cloud base) of ~500 cm−3 then decrease with further aerosol increases. This behaviour is caused by the initial transition from warm to mixed-phase rain followed by reduced efficiency of mixed-phase rain at very high drop concentrations. The response of tropical marine clouds to increasing aerosol is different to, and larger than, that of continental clouds. In the more humid tropical marine environment with low cloud bases we find that accumulated precipitation increases with increasing aerosol. The increase is driven by the transition from warm to mixed-phase rain. Our study suggests that the response of deep convective clouds to aerosol will be an important contribution to the spatial and temporal variability in cloud microphysics and precipitation.

scholarly journals Synergistic radar and radiometer retrievals of ice hydrometeors

2020 ◽  
Vol 13 (8) ◽  
pp. 4219-4245
Author(s):  
Simon Pfreundschuh ◽  
Patrick Eriksson ◽  
Stefan A. Buehler ◽  
Manfred Brath ◽  
David Duncan ◽  
...  
Keyword(s):  
Water Content ◽  
Information Content ◽  
Cloud Model ◽  
Cloud Microphysics ◽  
Retrieval Algorithm ◽  
Particle Model ◽  
Microphysical Properties ◽  
Millimeter Wavelengths ◽  
Wide Range ◽  
The Impact

Abstract. Remote sensing observations at sub-millimeter wavelengths provide higher sensitivity to small hydrometeors and low water content than observations at millimeter wavelengths, which are traditionally used to observe clouds and precipitation. They are employed increasingly in field campaigns to study cloud microphysics and will be integrated into the global meteorological observing system to measure the global distribution of ice in the atmosphere with the launch of the Ice Cloud Imager (ICI) radiometer on board the second generation of European operational meteorological satellites (Metop-SG). Observations at these novel wavelengths provide valuable information not only on their own but also in combination with complementary observations at other wavelengths. This study investigates the potential of combining passive sub-millimeter radiometer observations with a hypothetical W-band cloud radar for the retrieval of frozen hydrometeors. An idealized cloud model is used to investigate the information content of the combined observations and establish their capacity to constrain the microphysical properties of ice hydrometeors. A synergistic retrieval algorithm for airborne observations is proposed and applied to simulated observations from a cloud-resolving model. Results from the synergistic retrieval are compared to equivalent radar- and passive-only implementations in order to assess the benefits of the synergistic sensor configuration. The impact of the assumed ice particle shape on the retrieval results is assessed for all retrieval implementations. We find that the combined observations better constrain the microphysical properties of ice hydrometeors, which reduces uncertainties in retrieved ice water content and particle number concentrations for suitable choices of the ice particle model. Analysis of the retrieval information content shows that, although the radar contributes the largest part of the information in the combined retrieval, the radiometer observations provide complementary information over a wide range of atmospheric states. Furthermore, the combined observations yield slightly improved retrievals of liquid cloud water in mixed-phase clouds, pointing towards another potential application of combined radar–radiometer observations.

scholarly journals The response of precipitation to aerosol through riming and melting in deep convective clouds

2011 ◽  
Vol 11 (7) ◽  
pp. 3495-3510 ◽  
Author(s):  
Z. Cui ◽  
S. Davies ◽  
K. S. Carslaw ◽  
A. M. Blyth
Keyword(s):  
Cloud Model ◽  
Cloud Microphysics ◽  
Mixed Phase ◽  
Cloud Base ◽  
Spatial And Temporal Variability ◽  
Convective Clouds ◽  
Ice Particles ◽  
Wide Range ◽  
Deep Convective Clouds ◽  
The Impact

Abstract. We have used a 2-D axisymmetric, non-hydrostatic, bin-resolved cloud model to examine the impact of aerosol changes on the development of mixed-phase convective clouds. We have simulated convective clouds from four different sites (three continental and one tropical marine) with a wide range of realistic aerosol loadings and initial thermodynamic conditions (a total of 93 different clouds). It is found that the accumulated precipitation responds very differently to changing aerosol in the marine and continental environments. For the continental clouds, the scaled total precipitation reaches a maximum for aerosol that produce drop numbers at cloud base between 180–430 cm−3 when other conditions are the same. In contrast, all the tropical marine clouds show an increase in accumulated precipitation and deeper convection with increasing aerosol loading. For continental clouds, drops are rapidly depleted by ice particles shortly after the onset of precipitation. The precipitation is dominantly produced by melting ice particles. The riming rate increases with aerosol when the loading is very low, and decreases when the loading is high. Peak precipitation intensities tend to increase with aerosol up to drop concentrations (at cloud base) of ~500 cm−3 then decrease with further aerosol increases. This behaviour is caused by the initial transition from warm to mixed-phase rain followed by reduced efficiency of mixed-phase rain at very high drop concentrations. The response of tropical marine clouds to increasing aerosol is different to, and larger than, that of continental clouds. In the more humid tropical marine environment with low cloud bases we find that accumulated precipitation increases with increasing aerosol. The increase is driven by the transition from warm to mixed-phase rain. Our study suggests that the response of deep convective clouds to aerosol will be an important contribution to the spatial and temporal variability in cloud microphysics and precipitation.

Response Surface Mapping and Multi-Objective Optimization of Crowning and Tapers in Water-Lubricated Thrust Bearings

2019 ◽  
Author(s):  
Xin Deng ◽  
Cori Watson ◽  
Minhui He ◽  
Roger Fittro ◽  
Houston Wood
Keyword(s):  
Film Thickness ◽  
Power Loss ◽  
Performance Metrics ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Design Variables ◽  
Wide Range ◽  
Minimum Film Thickness ◽  
Bearing Design ◽  
The Impact

Abstract Fluid film bearings for turbomachinery are designed to support the loads applied by the rotor system. Oil-lubricated bearings are widely used in high speed rotating machines. However, environmental issues and risk-averse operations have made water lubricated bearings increasingly popular. Due to different viscosity properties between oil and water, the low viscosity of water decreases film thickness significantly. Crowning and tapers are two main ways to maintain the film thickness requirements in water lubrication, but no studies about the influence of these parameters on the film thickness in water-lubricated bearings have been reported. Therefore, further understanding of the performance associated with optimizing the bearing design with different weighted performance and their relationships to bearing design variables could be invaluable to bearing design engineers. This study explores the impact of three crowning and taper design variables on the performance of one tilting pad thrust bearing using the design of experiments techniques applied to a thermoelastohydrodynamic (TEHD) bearing model. The bearing design variables analyzed in this study include the radius of the ground-in crown, taper circumferential angle offset, and the vertical taper distance at the inner and outer radii. Each of the design variables is first varied over five levels, each in central composite design. The outputs from the TEHD numerical simulations used as performance measures for each bearing design point were the minimum film thickness, the film thickness at the pivot location, maximum film pressure and power loss. Multi-objective optimization was performed. A range of weighting parameters was selected for the optimization function to find a bearing design that maintains the minimum film thickness criterion while minimizing power loss. The resulting optimum design points allowed for a comparison between the design optimization at different weightings. This study demonstrates how designers can use these approaches to view the relationships between design variables and important performance metrics to design better bearing for a wide range of applications.

(How) Will I Socialize You? The Impact of Supervisor Initial Evaluations and Subsequent Support on the Socialization of Temporary Newcomers

2021 ◽  
Author(s):  
Lucas Dufour ◽  
Pablo I. Escribano ◽  
Massimo Maoret
Keyword(s):  
Job Satisfaction ◽  
Theoretical Model ◽  
Task Performance ◽  
Wide Range ◽  
Challenge Stress ◽  
Hindrance Stress ◽  
Negative Effect ◽  
The Impact ◽  
And Task

This study proposes and tests a new theoretical model explaining whether, and how, supervisors socialize “temporary newcomers,” defined as new organizational members who join an organization on a temporary basis, with a potential, but uncertain, opportunity of receiving a long-term job offer in the future. We suggest that under specific conditions, supervisors first evaluate temporary newcomers’ proactivity based on whether they positively stand out by proposing new feasible ideas and by promoting their achievements. On the basis of these initial evaluations, supervisors then decide whether to increase their support of newcomers’ creativity (using an investiture approach) or to intensify newcomers’ socialization by attempting to change their behavior (using a divestiture approach). When supervisors adopt an investiture approach, it positively influences temporary newcomers’ socialization adjustment outcomes, as indicated by increased newcomer job satisfaction, social integration, task performance, organizational and task socialization, challenge stress, and reduced hindrance stress. When supervisors instead adopt a divestiture approach, it has an opposite (thus negative) effect on the same socialization outcomes. We tested our theoretical model using a mix-method design, based on a three-wave longitudinal sample of 325 newcomer–supervisor dyads spanning a wide range of companies and industries, complemented with interviews of 41 supervisors.

Computers in Medical Care: A Review

1984 ◽  
Vol 23 (02) ◽  
pp. 63-74 ◽  
Author(s):  
Hans W. Gottinger
Keyword(s):  
Resource Allocation ◽  
Medical Care ◽  
Hospital Care ◽  
The Impact

SummaryThis survey provides an overview of major developments on the impact of computers in medical and hospital care over the last 25 years. Though the review emphasizes developments in the U. S. and their multi-faceted impacts upon resource allocation and regulation, a serious attempt is made to track those impacts being universally true in multinational environments.

THE IMPACT OF LEADERSHIP PRACTICES TO TEAM MEMBERS’ SATISFACTION

2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Chalimah .
Keyword(s):  
Conflict Resolution ◽  
Leadership Practices ◽  
Hotel Industry ◽  
Leader Behavior ◽  
Team Leader ◽  
Shop Floor ◽  
Team Members ◽  
Top Executives ◽  
Wide Range ◽  
The Impact

eamwork is becoming increasingly important to wide range of operations. It applies to all levels of the company. It is just as important for top executives as it is to middle management, supervisors and shop floor workers. Poor teamwork at any level or between levels can seriously damage organizational effectiveness. The focus of this paper was therefore to examine whether leadership practices consist of team leader behavior, conflict resolution style and openness in communication significantly influenced the team member’s satisfaction in hotel industry. Result indicates that team leader behavior and the conflict resolution style significantly influenced team member satisfaction. It was surprising that openness in communication did not affect significantly to the team members’ satisfaction.

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