scholarly journals Optimized distributed systems achieve significant performance improvement on sorted merging of massive VCF files

GigaScience ◽  
2018 ◽  
Vol 7 (6) ◽  
Author(s):  
Xiaobo Sun ◽  
Jingjing Gao ◽  
Peng Jin ◽  
Celeste Eng ◽  
Esteban G Burchard ◽  
...  
Keyword(s):  
Distributed Systems ◽  
Performance Improvement ◽  
Significant Performance

Consideration of structural constraints in passive rotor blade design for improved performance

2015 ◽  
Vol 119 (1222) ◽  
pp. 1513-1539 ◽  
Author(s):  
J. W. Lim
Keyword(s):  
Performance Improvement ◽  
Rotor Blade ◽  
Parametric Design ◽  
Control Point ◽  
Bending Moment ◽  
Structural Constraints ◽  
Design Variables ◽  
Significant Performance ◽  
Structural Redesign ◽  
Improved Performance

AbstractThis design study applied parameterisation to rotor blade for improved performance. In the design, parametric equations were used to represent blade planform changes over the existing rotor blade model. Design variables included blade twist, sweep, dihedral, and radial control point. Updates to the blade structural properties with changes in the design variables allowed accurate evaluation of performance objectives and realistic structural constraints – blade stability, steady moments (flap bending, chord bending, and torsion), and the high g manoeuvring pitch link loads. Performance improvement was demonstrated with multiple parametric designs. Using a parametric design with advanced aerofoils, the predicted power reduction was 1·0% in hover, 10·0% at μ = 0·30, and 17·0% at μ = 0·40 relative to the baseline UH-60A rotor, but these were obtained with a 35% increase in the steady chord bending moment at μ = 0·30 and a 20% increase in the half peak-to-peak pitch link load during the UH-60A UTTAS manoeuvre Low vibration was maintained for this design. More rigorous design efforts, such as chord tapering and/or structural redesign of the blade cross section, would enlarge the feasible design space and likely provide significant performance improvement.

Fiber nonlinearity compensation using optical phase conjugation in dispersion-managed coherent transmission systems

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jinqing Hao ◽  
Bingchen Han
Keyword(s):  
Performance Improvement ◽  
System Performance ◽  
Optical Transmission ◽  
Phase Conjugation ◽  
Fiber Amplifiers ◽  
Transmission Systems ◽  
Fiber Nonlinearity ◽  
Erbium Doped ◽  
Significant Performance ◽  
Transmission Link

Abstract In the discretely amplified transmission systems with erbium-doped fiber amplifiers, the system performance of nonlinearity-compensated optical transmission based on pre-dispersed spectral inversion (PSI) is investigated numerically. We find that PSI offers more significant performance improvement in dispersion-managed (DM) links than that in non-dispersion-managed (noDM) links. On the other hand, the DM link is more sensitive to the span offset from the center of the transmission link than noDM link. The performance difference between DM and noDM links is 1 dB if the span offset equals four spans in 20 × 90 km nonlinear transmission. Furthermore, we show that for the dispersion-managed transmission, in order to obtain the best system performance, the amount of pre-dispersion of the PSI, should be optimized over different dispersion maps.

scholarly journals Arabic Query Expansion Using WordNet and Association Rules

2016 ◽  
Vol 12 (3) ◽  
pp. 51-64 ◽  
Author(s):  
Ahmed Abbache ◽  
Farid Meziane ◽  
Ghalem Belalem ◽  
Fatma Zohra Belkredim
Keyword(s):  
Performance Improvement ◽  
Association Rules ◽  
Query Expansion ◽  
Arabic Language ◽  
Selection Method ◽  
Retrieval Performance ◽  
Retrieval Systems ◽  
Information Retrieval Systems ◽  
Significant Performance ◽  
Selection Of

Query expansion is the process of adding additional relevant terms to the original queries to improve the performance of information retrieval systems. However, previous studies showed that automatic query expansion using WordNet do not lead to an improvement in the performance. One of the main challenges of query expansion is the selection of appropriate terms. In this paper, the authors review this problem using Arabic WordNet and Association Rules within the context of Arabic Language. The results obtained confirmed that with an appropriate selection method, the authors are able to exploit Arabic WordNet to improve the retrieval performance. Their empirical results on a sub-corpus from the Xinhua collection showed that their automatic selection method has achieved a significant performance improvement in terms of MAP and recall and a better precision with the first top retrieved documents.

Consideration of structural constraints in passive rotor blade design for improved performance

2016 ◽  
Vol 120 (1232) ◽  
pp. 1604-1631 ◽  
Author(s):  
J.W. Lim
Keyword(s):  
Performance Improvement ◽  
Rotor Blade ◽  
Parametric Design ◽  
Control Point ◽  
Bending Moment ◽  
Structural Constraints ◽  
Design Variables ◽  
Significant Performance ◽  
Structural Redesign ◽  
Improved Performance

ABSTRACTThis design study applied parameterisation to rotor blade for improved performance. In the design, parametric equations were used to represent blade planform changes over the existing rotor blade model. Design variables included blade twist, sweep, dihedral and the radial control point. Updates to the blade structural properties with changes in the design variables allowed accurate evaluation of performance objectives and realistic structural constraints – blade stability, steady moments (flap bending, chord bending and torsion) and the high-g manoeuvre pitch link loads. Performance improvement was demonstrated with multiple parametric designs. Using a parametric design with advanced aerofoils, the predicted power reduction was 1.0% in hover, 10.0% at μ = 0.30 and 17.0% at μ = 0.40, relative to the baseline UH-60A rotor, but these were obtained with a 35% increase in the steady chord bending moment at μ = 0.30 and a 20% increase in the half peak-to-peak pitch link load during the UH-60A UTTAS manoeuvre. Low vibration was maintained for this design. More rigorous design efforts, such as chord tapering and/or structural redesign of the blade cross section, would enlarge the feasible design space and likely provide significant performance improvement.

Inertial Measurement Technology in the Satellite Navigation Environment

2000 ◽  
Vol 53 (2) ◽  
pp. 247-260 ◽  
Author(s):  
Victor F. Strachan
Keyword(s):  
Performance Improvement ◽  
Satellite Navigation ◽  
Measurement Technology ◽  
Navigation Systems ◽  
Valuable Contribution ◽  
Inertial Measurement ◽  
Significant Performance ◽  
Conceptual Discussion ◽  
And Performance ◽  
Satellite Navigation Systems

Inertial measurement technology can make a valuable contribution to the development of autonomous, sole-means Satellite Navigation Systems. The integration of inertial measurement technology and GPS can enable a significant performance improvement to the various configurations of GPS, WAAS and LAAS. This paper provides a conceptual discussion of the safety and performance benefits that inertial measurement and integration technology can bring to the satellite navigation environment.

scholarly journals Actionable Program Analyses for Improving Software Performance

2020 ◽  
pp. 113-140
Author(s):  
Marija Selakovic
Keyword(s):  
Software Development ◽  
Performance Improvement ◽  
Constant Pressure ◽  
Software Performance ◽  
Limited Knowledge ◽  
Significant Performance ◽  
Code Changes ◽  
Performance Analyses ◽  
Performance Issues ◽  
Code Optimizations

AbstractNowadays, we have greater expectations of software than ever before. This is followed by the constant pressure to run the same program on smaller and cheaper machines. To meet this demand, the application’s performance has become an essential concern in software development. Unfortunately, many applications still suffer from performance issues: coding or design errors that lead to performance degradation. However, finding performance issues is a challenging task: there is limited knowledge on how performance issues are discovered and fixed in practice, and current profilers report only where resources are spent, but not where resources are wasted. In this chapter, we investigate actionable performance analyses that help developers optimize their software by applying relatively simple code changes. We focus on optimizations that are effective, exploitable, recurring, and out-of-reach for compilers. These properties suggest that proposed optimizations lead to significant performance improvement, that they are easy to understand and apply, applicable across multiple projects, and that the compilers cannot guarantee that these optimizations always preserve the original program semantics. We implement our actionable analyses in practical tools and demonstrate their potential in improving software performance by applying relatively simple code optimizations.

scholarly journals Numeric Planning via Abstraction and Policy Guided Search

2017 ◽  
Author(s):  
León Illanes ◽  
Sheila A. McIlraith
Keyword(s):  
Performance Improvement ◽  
Real World ◽  
Planning Problem ◽  
Competitive Performance ◽  
Planning Techniques ◽  
Guided Search ◽  
The Real ◽  
Real World Application ◽  
Significant Performance ◽  
Planning Algorithms

The real-world application of planning techniques often requires models with numeric fluents. However, these fluents are not directly supported by most planners and heuristics. We describe a family of planning algorithms that takes a numeric planning problem and produces an abstracted representation that can be solved using any classical planner. The resulting abstract plan is generalized into a policy and then used to guide the search in the original numeric domain. We prove that our approach is sound, and we evaluate it on a set of standard benchmarks. We show that it can provide competitive performance when compared to other well-known algorithms for numeric planning, and a significant performance improvement in certain domains.

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