Results 1  10
of
322
Systems with finite communication bandwidth constraints—I: State estimation problems
 Stanford University, Stanford, CA
, 1997
"... Abstract—In this paper a new class of feedback control problems is introduced. Unlike classical models, the systems considered here have communication channel constraints. As a result, the issue of coding and communication protocol becomes an integral part of the analysis. Since these systems cannot ..."
Abstract

Cited by 180 (5 self)
 Add to MetaCart
Abstract—In this paper a new class of feedback control problems is introduced. Unlike classical models, the systems considered here have communication channel constraints. As a result, the issue of coding and communication protocol becomes an integral part of the analysis. Since these systems cannot be asymptotically stabilized if the underlying dynamics are unstable, a weaker stability concept called containability is introduced. A key result connects containability with an inequality equation involving the communication data rate and the rate of change of the state. Index Terms — Asymptotic stability, containability, feedback control, Kraft inequality.
Analysis of SRPT scheduling: Investigating unfairness
 In Proceedings of ACM SIGMETRICS
, 2001
"... The ShortestRemainingProcessingTime (SRPT) scheduling policy has long been known to be optimal for minimizing mean response time (sojourn time). Despite this fact, SRPT scheduling is rarely used in practice. It is believed that the performance improvements of SRPT over other scheduling policies s ..."
Abstract

Cited by 172 (17 self)
 Add to MetaCart
(Show Context)
The ShortestRemainingProcessingTime (SRPT) scheduling policy has long been known to be optimal for minimizing mean response time (sojourn time). Despite this fact, SRPT scheduling is rarely used in practice. It is believed that the performance improvements of SRPT over other scheduling policies stem from the fact that SRPT unfairly penalizes the large jobs in order to help the small jobs. This belief has led people to instead adopt “fair ” scheduling policies such as ProcessorSharing (PS), which produces the same expected slowdown for jobs of all sizes. This paper investigates formally the problem of unfairness in SRPT scheduling as compared with PS scheduling. The analysis assumes an M/G/1 model, and emphasizes job size distributions with a heavytailed property, as are characteristic of empirical workloads. The analysis shows that the degree of unfairness under SRPT is surprisingly small. The M/G/1/SRPT and M/G/1/PS queues are also analyzed under overload and closedform expressions for mean response time as a function of job size are proved in this setting.
Analysis of LAS Scheduling for Job Size Distributions with High Variance
, 2003
"... Recent studies of Internet traffic have shown that flow size distributions often exhibit a high variability property in the sense that most of the flows are short and more than half of the total load is constituted by a small percentage of the largest flows. In the light of this observation, it is ..."
Abstract

Cited by 63 (8 self)
 Add to MetaCart
(Show Context)
Recent studies of Internet traffic have shown that flow size distributions often exhibit a high variability property in the sense that most of the flows are short and more than half of the total load is constituted by a small percentage of the largest flows. In the light of this observation, it is interesting to revisit scheduling policies that are known to favor small jobs in order to quantify the benefit for small and the penalty for large jobs. Among all scheduling policies that do not require knowledge of job size, the least attained service (LAS) scheduling policy is known to favor small jobs the most.
On some inequalities for the gamma and psi functions
 MATH. COMP
, 1997
"... We present new inequalities for the gamma and psi functions, and we provide new classes of completely monotonic, starshaped, and superadditive functions which are related to Γ and ψ. Euler’s gamma function Γ(x) = ..."
Abstract

Cited by 55 (2 self)
 Add to MetaCart
We present new inequalities for the gamma and psi functions, and we provide new classes of completely monotonic, starshaped, and superadditive functions which are related to Γ and ψ. Euler’s gamma function Γ(x) =
MetiTarski: An Automatic Theorem Prover for RealValued Special Functions
"... Abstract Many theorems involving special functions such as ln, exp and sin can be proved automatically by MetiTarski: a resolution theorem prover modified to call a decision procedure for the theory of real closed fields. Special functions are approximated by upper and lower bounds, which are typica ..."
Abstract

Cited by 42 (7 self)
 Add to MetaCart
(Show Context)
Abstract Many theorems involving special functions such as ln, exp and sin can be proved automatically by MetiTarski: a resolution theorem prover modified to call a decision procedure for the theory of real closed fields. Special functions are approximated by upper and lower bounds, which are typically rational functions derived from Taylor or continued fraction expansions. The decision procedure simplifies clauses by deleting literals that are inconsistent with other algebraic facts. MetiTarski simplifies arithmetic expressions by conversion to a recursive representation, followed by flattening of nested quotients. Applications include verifying hybrid and control systems.
Several integral inequalities
 ONLINE: http://jipam.vu.edu.au/article.php?sid=113
"... Communicated by J. Pecarić ABSTRACT. In this article, an open problem posed in [12] is studied once again, and, following closely theorems and methods from [5], some extensions of several integral inequalities are obtained. ..."
Abstract

Cited by 37 (4 self)
 Add to MetaCart
Communicated by J. Pecarić ABSTRACT. In this article, an open problem posed in [12] is studied once again, and, following closely theorems and methods from [5], some extensions of several integral inequalities are obtained.
Local estimates for some fully nonlinear elliptic equations
, 2005
"... We present a method to derive local estimates for some classes of fully nonlinear elliptic equations. The advantage of our method is that we derive Hessian estimates directly from C 0 estimates. Also, the method is flexible and can be applied to a large class of equations. ..."
Abstract

Cited by 35 (2 self)
 Add to MetaCart
(Show Context)
We present a method to derive local estimates for some classes of fully nonlinear elliptic equations. The advantage of our method is that we derive Hessian estimates directly from C 0 estimates. Also, the method is flexible and can be applied to a large class of equations.
On Name Resolution in PeertoPeer Networks
 In Proceedings of the 2nd ACM Worskhop on Principles of Mobile Commerce (POMC
, 2002
"... An efficient name resolution scheme is the cornerstone of any peertopeer network. The foundation of an efficient name resolution scheme is a dynamic network topology that determines the neighbor relationships to be maintained by the nodes in the network. The name resolution scheme proposed by P ..."
Abstract

Cited by 33 (4 self)
 Add to MetaCart
(Show Context)
An efficient name resolution scheme is the cornerstone of any peertopeer network. The foundation of an efficient name resolution scheme is a dynamic network topology that determines the neighbor relationships to be maintained by the nodes in the network. The name resolution scheme proposed by Plaxton, Rajaraman, and Richa, which we hereafter refer to as the PRR scheme, is a scalable scheme that also provides provable locality properties on a certain class of growthrestricted metric spaces. On arbitrary metric spaces, however, some performance bounds of PRR are significantly weakened. In this paper, we define a class of network topologies called hyperdelta networks and observe that the PRR topology may be viewed as a random hyperdelta network. We then propose SPRR (simplified PRR), a variant of the PRR scheme that performs well on arbitrary metric spaces. SPRR imposes additional constraints on PRR neighbor selection by placing the nodes on a cycle. Although SPRR does not provide as strong locality properties as PRR, it exploits locality heuristically yet effectively. Finally, a significant level of fault tolerance can be achieved in SPRR without adding much complexity.
SelfAlignment in Words and their Applications
 J. Algorithms
, 1992
"... Some quantities associated with periodicities in words are analyzed within the Bernoulli probabilistic model. In particular, the following problem is addressed. Assume that a string X is given, with symbols emitted randomly but independently according to some known distribution of probabilities. T ..."
Abstract

Cited by 27 (8 self)
 Add to MetaCart
Some quantities associated with periodicities in words are analyzed within the Bernoulli probabilistic model. In particular, the following problem is addressed. Assume that a string X is given, with symbols emitted randomly but independently according to some known distribution of probabilities. Then, for each pair (W , Z) of distinct suffixes of X, the expected length of the longest common prefix of W and Z is sought. The collection of these lengths, that are called here selfalignments, plays a crucial role in several algorithmic problems on words, such as building suffix trees or inverted files, detecting squares and other regularities, computing substring statistics, etc. The asymptotically best algorithms for these problems are quite complex and thus risk to be unpractical. The present analysis of selfalignments and related measures suggests that, in a variety of cases, more straightforward algorithmic solutions may yield comparable or even better performances. Key words and ph...