Network Speed Scaling

2021 ◽  
Vol 48 (3) ◽  
pp. 61-62
Author(s):  
Rahul Vaze ◽  
Jayakrishnan Nair
Keyword(s):  
Directed Acyclic Graph ◽  
Variable Speed ◽  
Consumption Function ◽  
Power Functions ◽  
Path Diversity ◽  
Speed Scaling ◽  
Worst Case ◽  
Feasible Path ◽  
Network Speed ◽  
Increasing Function

Speed scaling for a network of servers represented by a directed acyclic graph is considered. Jobs arrive at a source server, with a specified destination server, and are defined to be complete once they are processed by all servers on any feasible path between the source and the corresponding destination. Each server has variable speed, with power consumption function P, a convex increasing function of the speed. The objective is to minimize the sum of the flow time (summed across jobs) and the energy consumed by all the servers, which depends on how jobs are routed, as well as how server speeds are set. Algorithms are derived for both the worst case and stochastic job arrivals setting, whose competitive ratio depends only on the power functions and path diversity in the network, but is independent of the workload.

A Robust Pressure Controller for a Variable Speed AC Motor Pump: Application to Aircraft Hydraulic Power Packages

2018 ◽  
Author(s):  
Nils Trochelmann ◽  
Phillip Bischof Stump ◽  
Frank Thielecke ◽  
Dirk Metzler ◽  
Stefan Bassett
Keyword(s):  
Distribution Systems ◽  
Controller Design ◽  
Dynamic Performance ◽  
Operating Conditions ◽  
Gear Pump ◽  
Variable Speed ◽  
Hydraulic Power ◽  
Worst Case ◽  
Wide Range ◽  
Pressure Controller

Highly integrated electro-hydraulic power packages with electric motor-driven pumps (EMP) are a key technology for future aircraft with electric distribution systems. State of the art aircraft EMPs are robust but lack efficiency, availability, and have high noise emissions. Variable speed fixed displacement (VSFD-) EMPs, combining a permanent magnet synchronous motor and an internal gear pump, show promising properties regarding noise reduction and energy efficiency. Though, meeting the strict dynamic requirements is tough with this EMP-concept. Speed limitations and inertia impose strong restrictions on the achievable dynamic performance. Moreover, the requirements must be met under a wide range of operating conditions. For a prototype aircraft VSFD-EMP a robust pressure controller design is proposed in this paper. In a first step the operating conditions of the EMP are defined, analyzing environmental conditions and impacts of the interfacing aircraft systems. Nonlinear and linear control design models are developed and validated by measurements at an EMP test rig built for this project. A conventional cascade pressure control concept is selected. This is motivated by the demand for simple, reliable, and proven solutions in aerospace applications. A controller is designed by applying classical loop shaping techniques. Robust stability and performance of the system are investigated through a subsequent μ-analysis. Finally, the controller is tested under nominal and worst case conditions in nonlinear simulations.

Scheduling Deteriorating Jobs with Availability Constraints to Minimize the Makespan

2016 ◽  
Vol 33 (06) ◽  
pp. 1650048
Author(s):  
Chuanli Zhao ◽  
Hengyong Tang
Keyword(s):  
Polynomial Time ◽  
Approximation Scheme ◽  
Deteriorating Jobs ◽  
Worst Case ◽  
Time Approximation ◽  
Starting Time ◽  
Polynomial Time Approximation Algorithm ◽  
Availability Constraints ◽  
Increasing Function ◽  
Polynomial Time Approximation

In this paper, we consider the scheduling problem in which the processing time of a job is a linear increasing function of its starting time and machine with availability constraints. The objective is to minimize the makespan. We first present a fully polynomial-time approximation scheme (FPTAS) for the case with a single machine. We then show that there exists no polynomial time approximation algorithm with a constant worst-case bound for the case with two identical machines unless [Formula: see text].

Network speed scaling

2020 ◽  
Vol 144 ◽  
pp. 102145
Author(s):  
Rahul Vaze ◽  
Jayakrishnan Nair
Keyword(s):  
Speed Scaling ◽  
Network Speed

Linear pattern matching of compressed terms and polynomial rewriting

2018 ◽  
Vol 28 (8) ◽  
pp. 1415-1450 ◽  
Author(s):  
MANFRED SCHMIDT-SCHAUß
Keyword(s):  
Pattern Matching ◽  
Polynomial Time ◽  
Directed Acyclic Graph ◽  
Term Rewriting ◽  
Single Step ◽  
Worst Case ◽  
Linear Pattern ◽  
Input Size ◽  
Straight Line ◽  
Rewrite System

We consider term rewriting under sharing in the form of compression by singleton tree grammars (STG), which is more general than the term dags. Algorithms for the subtasks of rewriting are analysed: finding a redex for rewriting by locating a position for a match, performing a rewrite step by constructing the compressed result and executing a sequence of rewrite steps. The first main result is that locating a match of a linear termsin another termtcan be performed in polynomial time ifs,tare both STG-compressed. This generalizes results on matching of STG-compressed terms, matching of straight-line-program-compressed strings with character-variables, where every variable occurs at most once, and on fully compressed matching of strings. Also, for the case wheresis directed-acyclic-graph (DAG)-compressed, it is shown that submatching can be performed in polynomial time. The general case of compressed submatching can be computed in non-deterministic polynomial time, and an algorithm is described that may be exponential in the worst case, its complexity isnO(k), wherekis the number of variables with double occurrences insandnis the size of the input. The second main result is that in case there is an oracle for the redex position, a sequence ofmparallel or single-step rewriting steps under STG-compression can be performed in polynomial time. This generalizes results on DAG-compressed rewriting sequences. Combining these results implies that for an STG-compressed term rewrite system with left-linear rules,mparallel or single-step term rewrite steps can be performed in polynomial time in the input sizenandm.

Optimal speed scaling under arbitrary power functions

2009 ◽  
Vol 37 (2) ◽  
pp. 39-41 ◽  
Author(s):  
Lachlan L.H. Andrew ◽  
Adam Wierman ◽  
Ao Tang
Keyword(s):  
Power Functions ◽  
Speed Scaling ◽  
Arbitrary Power ◽  
Optimal Speed

scholarly journals Weighted Hardy Operators in Complementary Morrey Spaces

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Dag Lukkassen ◽  
Lars-Erik Persson ◽  
Stefan Samko
Keyword(s):  
Morrey Spaces ◽  
Bounded Domains ◽  
Weighted Lebesgue Space ◽  
Power Functions ◽  
Logarithmic Factor ◽  
Hardy Type ◽  
Weighted Hardy Operators ◽  
Increasing Function ◽  
Hardy Operators ◽  
Hardy Type Operators

We study the weightedp→q-boundedness of the multidimensional weighted Hardy-type operatorsHwαandℋwαwith radial type weightw=w(|x|), in the generalized complementary Morrey spacesℒ∁{0}p,ψ(ℝn)defined by an almost increasing functionψ=ψ(r). We prove a theorem which provides conditions, in terms of some integral inequalities imposed onψandw, for such a boundedness. These conditions are sufficient in the general case, but we prove that they are also necessary when the functionψand the weightware power functions. We also prove that the spacesℒ∁{0}p,ψ(Ω)over bounded domains Ω are embedded between weighted Lebesgue spaceLpwith the weightψand such a space with the weightψ, perturbed by a logarithmic factor. Both the embeddings are sharp.

Processor-Network Speed Scaling for Energy–Delay Tradeoff in Smartphone Applications

2016 ◽  
Vol 24 (3) ◽  
pp. 1647-1660 ◽  
Author(s):  
Jeongho Kwak ◽  
Okyoung Choi ◽  
Song Chong ◽  
Prasant Mohapatra
Keyword(s):  
Smartphone Applications ◽  
Speed Scaling ◽  
Network Speed

Propagating Distributions Up Directed Acyclic Graphs

1999 ◽  
Vol 11 (1) ◽  
pp. 215-227 ◽  
Author(s):  
Eric B. Baum ◽  
Warren D. Smith
Keyword(s):  
Graphical Models ◽  
Directed Acyclic Graph ◽  
Search Tree ◽  
Directed Acyclic Graphs ◽  
Game Tree ◽  
Worst Case ◽  
Exponential Time ◽  
Acyclic Graphs ◽  
Game Trees ◽  
Directed Growth

In a previous article, we considered game trees as graphical models. Adopting an evaluation function that returned a probability distribution over values likely to be taken at a given position, we described how to build a model of uncertainty and use it for utility-directed growth of the search tree and for deciding on a move after search was completed. In some games, such as chess and Othello, the same position can occur more than once, collapsing the game tree to a directed acyclic graph (DAG). This induces correlations among the distributions at sibling nodes. This article discusses some issues that arise in extending our algorithms to a DAG. We give a simply described algorithm for correctly propagating distributions up a game DAG, taking account of dependencies induced by the DAG structure. This algorithm is exponential time in the worst case. We prove that it is #P complete to propagate distributions up a game DAG correctly. We suggest how our exact propagation algorithm can yield a fast but inexact heuristic.

Instrumentation for detecting channelling radiation in the high-voltage electron microscope

1983 ◽  
Vol 41 ◽  
pp. 318-319
Author(s):  
J. H. Butler ◽  
C. J. Humphreys
Keyword(s):  
Monochromatic Light ◽  
Incident Beam ◽  
Laboratory Frame ◽  
Relativistic Electrons ◽  
Voltage Electron ◽  
Dipole Emission ◽  
Sinusoidal Oscillations ◽  
Pass Through ◽  
Incident Beam Energy ◽  
Increasing Function

Electromagnetic radiation is emitted when fast (relativistic) electrons pass through crystal targets which are oriented in a preferential (channelling) direction with respect to the incident beam. In the classical sense, the electrons perform sinusoidal oscillations as they propagate through the crystal (as illustrated in Fig. 1 for the case of planar channelling). When viewed in the electron rest frame, this motion, a result of successive Bragg reflections, gives rise to familiar dipole emission. In the laboratory frame, the radiation is seen to be of a higher energy (because of the Doppler shift) and is also compressed into a narrower cone of emission (due to the relativistic “searchlight” effect). The energy and yield of this monochromatic light is a continuously increasing function of the incident beam energy and, for beam energies of 1 MeV and higher, it occurs in the x-ray and γ-ray regions of the spectrum. Consequently, much interest has been expressed in regard to the use of this phenomenon as the basis for fabricating a coherent, tunable radiation source.

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