scholarly journals A State of Art Survey for OS Performance Improvement

2018 ◽  
Vol 6 (3) ◽  
pp. 118-123 ◽  
Author(s):  
Lailan M. Haji ◽  
Subhi R.M. Zeebaree ◽  
Karwan Jacksi ◽  
Diyar Q. Zeebaree
Keyword(s):  
Performance Improvement ◽  
Critical Issue ◽  
The Past ◽  
Performance Requirements ◽  
And Performance ◽  
Measurement And Evaluation ◽  
The Stability ◽  
High Level ◽  
Multiple Metrics ◽  
Selection Of

Through the huge growth of heavy computing applications which require a high level of performance, it is observed that the interest of monitoring operating system performance has also demanded to be grown widely. In the past several years since OS performance has become a critical issue, many research studies have been produced to investigate and evaluate the stability status of OSs performance. This paper presents a survey of the most important and state of the art approaches and models to be used for performance measurement and evaluation. Furthermore, the research marks the capabilities of the performance-improvement of different operating systems using multiple metrics. The selection of metrics which will be used for monitoring the performance depends on monitoring goals and performance requirements. Many previous works related to this subject have been addressed, explained in details, and compared to highlight the top important features that will very beneficial to be depended for the best approach selection.

Patterns of achievement-motivated behavior and performance as predictors for future success in rowing: A person-oriented study

2020 ◽  
pp. 174795412095365
Author(s):  
Michael J Schmid ◽  
Achim Conzelmann ◽  
Claudia Zuber
Keyword(s):  
National Level ◽  
Psychological Characteristics ◽  
Performance Variables ◽  
The Past ◽  
Motivated Behavior ◽  
Talent Selection ◽  
Future Success ◽  
And Performance ◽  
High Level ◽  
Selection Of

Talent selection in rowing is often solely based on anthropometric and performance variables, even though psychological characteristics are considered to be important contributors to successful talent development. Because multidimensional talent models and holistic theories represent the state-of-the-art in talent research, we aimed to find patterns connecting psychological and performance variables to future success in rowing. Therefore, 22 coaches rated the achievement-motivated behavior represented by the variables proactivity, ambition and commitment of 65 competitive to high-level athletes ( Mage = 17.2 ± 1.55 years) for the past year (t1). Additionally, the athletes performed several 2,000 m ergometer tests during that same period. At t2 (30 months later), each rower’s performance was evaluated based on the success at different competitions. To examine the results, we used the person-oriented Linking of Clusters after removal of a Residue (LICUR) method to identify the relationships between the achievement-motivated behavior and ergometer results at t1 and the success at t2. The rowers could be assigned to five clusters. Although the highly motivated rowers were not the fastest on the ergometer at t1, they were more likely to be in highest performance level at t2 compared to the other clusters (OR = 3.5, p < .05). By contrast, all the ambitionless rowers and unmotivated rowers were either racing at national level or had dropped out. In conclusion, certain patterns of achievement-motivated behavior and current performance are associated with future success (30 months later). The consideration of achievement-motivated behavior in the selection of rowers seems promising in this context.

Map Width Enhancement Technique for a Turbocharger Compressor

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes were designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor was highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and noncavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

The CHAL336 Benchmark Set: How Well Do Quantum-Chemical Methods Describe Chalcogen-Bonding Interactions?

2021 ◽  
Author(s):  
Nisha Mehta ◽  
Thomas Fellowes ◽  
JONATHAN WHITE ◽  
Lars Goerigk
Keyword(s):  
Density Functional ◽  
Noncovalent Interactions ◽  
Interaction Energies ◽  
Chemical Methods ◽  
Dft Methods ◽  
The Past ◽  
Quantum Chemical Methods ◽  
London Dispersion ◽  
High Level ◽  
Selection Of

<div> <div> <div> <p>We present the CHAL336 benchmark set—the most comprehensive database for the assessment of chalcogen-bonding (CB) interactions. After careful selection of suitable systems and identification of three high-level reference methods, the set comprises 336 dimers each consisting of up to 49 atoms and covers both σ- and π-hole interactions across four categories: chalcogen-chalcogen, chalcogen-π, chalcogen-halogen, and chalcogen-nitrogen interactions. In a subsequent study of DFT methods, we re- emphasize the need for using proper London-dispersion corrections when treating noncovalent interactions. We also point out that the deterioration of results and systematic overestimation of interaction energies for some dispersion-corrected DFT methods does not hint at problems with the chosen dispersion correction, but is a consequence of large density-driven errors. We conclude this work by performing the most detailed DFT benchmark study for CB interactions to date. We assess 98 variations of dispersion- corrected and -uncorrected DFT methods, and carry out a detailed analysis of 72 of them. Double-hybrid functionals are the most reliable approaches for CB interactions, and they should be used whenever computationally feasible. The best three double hybrids are SOS0-PBE0-2-D3(BJ), revDSD-PBEP86-D3(BJ), and B2NCPLYP-D3(BJ). The best hybrids in this study are ωB97M-V, PW6B95-D3(0), and PW6B95-D3(BJ). We do not recommend using any lower-rung DFT methods nor the popular B3LYP and MP2 approaches, which have been used to describe CB interactions in the past. We hope to inspire a change in computational protocols surrounding CB interactions that leads away from the commonly used, popular methods to the more robust and accurate ones recommended herein. We would also like to encourage method developers to use our set for the investigation and reduction of density-driven errors in new density functional approximations. </p> </div> </div> </div>

Map Width Enhancement Technique for a Turbocharger Compressor

2012 ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes have been designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor has been highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and non-cavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

scholarly journals The CHAL336 Benchmark Set: How Well Do Quantum-Chemical Methods Describe Chalcogen-Bonding Interactions?

2021 ◽  
Author(s):  
Nisha Mehta ◽  
Thomas Fellowes ◽  
JONATHAN WHITE ◽  
Lars Goerigk
Keyword(s):  
Density Functional ◽  
Noncovalent Interactions ◽  
Interaction Energies ◽  
Chemical Methods ◽  
Dft Methods ◽  
The Past ◽  
Quantum Chemical Methods ◽  
London Dispersion ◽  
High Level ◽  
Selection Of

<div> <div> <div> <p>We present the CHAL336 benchmark set—the most comprehensive database for the assessment of chalcogen-bonding (CB) interactions. After careful selection of suitable systems and identification of three high-level reference methods, the set comprises 336 dimers each consisting of up to 49 atoms and covers both σ- and π-hole interactions across four categories: chalcogen-chalcogen, chalcogen-π, chalcogen-halogen, and chalcogen-nitrogen interactions. In a subsequent study of DFT methods, we re- emphasize the need for using proper London-dispersion corrections when treating noncovalent interactions. We also point out that the deterioration of results and systematic overestimation of interaction energies for some dispersion-corrected DFT methods does not hint at problems with the chosen dispersion correction, but is a consequence of large density-driven errors. We conclude this work by performing the most detailed DFT benchmark study for CB interactions to date. We assess 98 variations of dispersion- corrected and -uncorrected DFT methods, and carry out a detailed analysis of 72 of them. Double-hybrid functionals are the most reliable approaches for CB interactions, and they should be used whenever computationally feasible. The best three double hybrids are SOS0-PBE0-2-D3(BJ), revDSD-PBEP86-D3(BJ), and B2NCPLYP-D3(BJ). The best hybrids in this study are ωB97M-V, PW6B95-D3(0), and PW6B95-D3(BJ). We do not recommend using any lower-rung DFT methods nor the popular B3LYP and MP2 approaches, which have been used to describe CB interactions in the past. We hope to inspire a change in computational protocols surrounding CB interactions that leads away from the commonly used, popular methods to the more robust and accurate ones recommended herein. We would also like to encourage method developers to use our set for the investigation and reduction of density-driven errors in new density functional approximations. </p> </div> </div> </div>

A Descriptive-Comparative Study of Implementation and Performance of Family Physician Program in Iran and Selected Countries

2020 ◽  
Author(s):  
Bita SEPEHRI ◽  
Reza GHAFFARI ◽  
Alireza JEDDIAN ◽  
Fariba SALEK ◽  
Robabeh EMROUZI ◽  
...  
Keyword(s):  
Comparative Study ◽  
Family Physician ◽  
The Past ◽  
Study Results ◽  
Ease Of Access ◽  
And Performance ◽  
Access To Data ◽  
Implementation Status ◽  
Criteria For Selection ◽  
Selection Of

Background: The implementation of Family Physician Program (FPP) in Iran during the past decade, despite of its numerous achievements, has faced many challenges. We aimed to compare the implementation and the performance of FPP in Iran with selected countries, in order to analyze those challenges and suggest potential solutions. Methods: This current descriptive-comparative study was conducted in 2015. The implementation and the performance of the FPP in Iran and six countries (Canada, Australia, United Kingdom, Denmark, United States and the Netherlands) were described and compared. The criteria for selection of these countries were the existence of well-established FFPs and ease of access to data required to conduct the research. A documentation checklist of the implementation status and FPP practice was prepared. The checklist’s content validity was established by an independent 10 member expert panel, specializing in the field of Family Medicine. The conclusive checklist was finalized for each country, based on inter-rater agreement of the three researchers and used as a basis for this comparative study. Results: This study revealed significant differences in implementation of the FPP and relatively low differences in FPP performance between Iran and the selected countries. Conclusion: Implementation and performance of FPP and patient referral system in Iran struggles with serious challenges and burdens, in contrast with the selected reviewed countries. As such, modification of the FPP in Iran seems to be a must. Such modification may include developing educational programs for FPs, clearly defining the duties and practices of FPs, and revising their reimbursement and employment status.

Comparing LQG/LTR and the SDRE Techniques for Hybrid Fully-Connected PLL Network Control

2013 ◽  
Author(s):  
Átila Madureira Bueno ◽  
Angelo Marcelo Tusset ◽  
Diego Paolo Ferruzzo Correa ◽  
José Roberto Castilho Piqueira ◽  
José Manoel Balthazar
Keyword(s):  
Integrated Circuits ◽  
Network Control ◽  
Clock Signal ◽  
Clock Distribution ◽  
Signal Distribution ◽  
Performance Requirements ◽  
Distribution Process ◽  
And Performance ◽  
The Stability ◽  
Fully Connected

Synchronization plays an important role in telecommunication systems and integrated circuits. The Master-Slave is a commonly used strategy for clock signal distribution. However, due to the wireless networks development and the higher operation frequency of integrated circuits, the Mutually-Connected clock distribution strategies are becoming important, and the Fully-Connected strategy appears as a convenient engineering solution. The main drawback of the Fully-Connected architecture is the definition of control algorithms that assure the stability of the network sinchronization. In hybrid synchronization techniques groups of nodes synchronized by the Fully-Connected architecture are synchronized with network master clocks by using the Master-Slave tecnique. In this arrangement, if a route of clock signal distribution becomes inoperative, the group of Fully-Connected nodes retain for some time the original phase and frequency received from the network. The Fully-Connected architecture complexity imposes difficulties to satisfy both stability and performance requirements in the control system design. For that reason the multi-variable LQG/LTR and the SDRE control techniques are applied in order to fulfill both stability and performance requirements. The performance of both techniques are compared, and the results seems to confirm the improvement in the transient response and in the precision of the clock distribution process.

Correlation and Performance Estimation of Clone Detection Tools

2018 ◽  
Vol 9 (2) ◽  
pp. 55-71
Author(s):  
Pratiksha Gautam ◽  
Hemraj Saini
Keyword(s):  
Performance Estimation ◽  
User Requirements ◽  
Clone Detection ◽  
The Past ◽  
And Performance ◽  
Tools And Methods ◽  
Selection Of

Over the past few decades, many tools and methods have been proposed by several researchers to detect clones automatically in programs and software. Nevertheless, it is not yet clear how to evaluate these tools in terms of accuracy, scalability, and portability. However, all of these tools have some merits and limitations but the application of these tools depends on the user requirements, so it is necessary for the user that they should be aware of the tools and its distinguishing aspects. This article presents the performance of six clone detection tools in terms of accuracy, scalability, and portability. The aim of this study is to make the selection of tools easy for detection of copied code.

scholarly journals Event-Based Stabilization over Networks with Transmission Delays

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Xiangyu Meng ◽  
Tongwen Chen
Keyword(s):  
Feedback Gain ◽  
Pendulum System ◽  
Transmission Delays ◽  
Performance Requirements ◽  
Inverted Pendulum System ◽  
Event Triggering ◽  
Continuous Feedback ◽  
And Performance ◽  
The Stability ◽  
Event Based

This paper investigates asymptotic stabilization for linear systems over networks based on event-driven communication. A new communication logic is proposed to reduce the feedback effort, which has some advantages over traditional ones with continuous feedback. Considering the effect of time-varying transmission delays, the criteria for the design of both the feedback gain and the event-triggering mechanism are derived to guarantee the stability and performance requirements. Finally, the proposed techniques are illustrated by an inverted pendulum system and a numerical example.

Sign in / Sign up

Export Citation Format

Share Document