Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Department of Analytics

TCP Low Priority (TCP-LP), a algorithm whose goal is to utilize only the excess network bandwidth as compared to the "fair share" of bandwidth as targeted by TCP. Service prioritization among different traffic classes is an important goal for the Internet. Conventional approaches to solving this problem consider the existing best-effort class as the low-priority class, and attempt to develop mechanisms that provide "better-than-best-effort" service. We explore the opposite approach, and devise a new distributed algorithm to realize a low-priority service (as compared to the existing best effort) from the network endpoints. To this end, we develop TCP Low Priority (TCP-LP), a distributed algorithm whose goal is to utilize only the excess network bandwidth as compared to the "fair share" of bandwidth as targeted by TCP. The key mechanisms unique to TCP-LP congestion control are the use of one-way packet delays for early congestion indications and a TCP-transparent congestion avoidance policy. The results of our simulation and Internet experiments show that: •TCP-LP is largely non-intrusive to TCP traffic. •Both single and aggregate TCP-LP flows are able to successfully utilize excess network bandwidth; moreover, multiple TCP-LP flows share excess bandwidth fairly. •Substantial amounts of excess bandwidth are available to the low-priority class, even in the presence of "greedy" TCP flows. •Despite their low-priority nature, TCP-LP flows are able to utilize significant amounts of available bandwidth in a wide-area network environment.

Department of Information Security

School of Computer Science and Engineering

Vellore Campus

Fulltext

IEEE/ACM Transactions on Networking

TCP-LP: low-priority service via end-point congestion control

Active networks provide a programmable user-network interface that supports dynamic modification of the network's behavior. Network nodes, in addition to forwarding packets, perform customized computation on the messages flowing through them. Resources in an active network mainly comprise of CPU and bandwidth. An efficient allocation is required for the optimal utilization of the resources. In this paper, the resources are estimated using a smoothing technique and compared against the actual requirements. An algorithm is designed for the fair allocation of resources. A policy-based approach is also designed based on constraints related to resource requirements, which will ensure the overall QoS © 2006 IEEE.

World University root node

Proceedings - 2006 IEEE International Conference on Networks, ICON 2006 - Networking-Challenges and Frontiers

Resource estimation and policy based allocation for quality of service in active networks

Ambiguity plays an important role in checking the relevances of formalism for natural language processing. As contextual grammars were shown to be an appropriate description for natural languages, analyzing syntactic ambiguity of contextual grammars deserves a special attention. The levels of ambiguity of internal contextual grammars are defined depending on the information used for describing a derivation. In this paper, we continue the study on ambiguity of internal contextual grammars which was investigated in [3] and [13]. We achieve solutions to the following open problems addressed in the above papers. For each (i, j) ∈ {(2, 1), (1, 0), (0, 1)}, are there languages which are inherently i-ambiguous with respect to grammars with arbitrary selector, but j-ambiguous with respect to grammars with finite selector? © Springer-Verlag Berlin Heidelberg 2006.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Further results on syntactic ambiguity of internal contextual grammars

In this paper, we present a few results which are of interest for the potential application of contextual grammars to natural languages. We introduce two new classes of internal contextual grammars, called end-marked maximal depth-first and inner end-marked maximal depth-first contextual grammars. We analyze the new variants with respect to the basic properties of the mildly context sensitive languages. With this aim, we show that (i) the three basic non-context-free constructions in natural languages can be realized upon using these variants, (ii) the membership problem for these family of languages is decidable in polynomial time algorithm, (iii) the family of languages generated by end-marked maximal depth-first grammars contains non-semilinear languages. We also solve the following open problem addressed in [3] and [1]: whether the families of languages generated by maximal depth-first and maximal local contextual grammars are semilinear or not? © Springer-Verlag Berlin Heidelberg 2006.

End-marked maximal depth-first contextual grammars

In this paper, we continue the study of ambiguity of internal contextual grammars which was investigated in Ilie [On ambiguity in internal contextual languages, in: C. Martin-Vide (Ed.), Second Int. Conf. on Mathematical Linguistics, Tarragona, 1996, John Benjamins, Amsterdam, 1997, pp. 29-45] and Martin-Vide et al. [Attempting to define the ambiguity in internal contextual languages, in: C. Martin-Vide (Ed.), Second Int. Conf. on Mathematical Linguistics, Tarragona, 1996, John Benjamins, Amsterdam, 1997, pp. 59-81]. We solve some open problems formulated in these papers. The main results are: (i) there are inherently 1-ambiguous languages with respect to internal contextual grammars with arbitrary choice which are 0-unambiguous with respect to finite choice, (ii) there are inherently 2-ambiguous languages with respect to internal contextual grammars with arbitrary choice which are 1-unambiguous with respect to regular choice, and (iii) there are inherently 2-ambiguous languages with respect to depth-first internal contextual grammars with arbitrary choice which are 1-unambiguous with respect to finite choice. © 2006 Elsevier B.V. All rights reserved.

Theoretical Computer Science

A note on ambiguity of internal contextual grammars

In this article we introduce the map operator on a list, define list indexing the cons operator and establish their properties. Parallel notions and properties for fuzzy lists are also considered. © 2003 Elsevier Inc. All rights reserved.

Information Sciences

Some more properties of lists and fuzzy lists

The notion of list was redefined [Int. Sci. 132 (1-4) (2001) 241] very recently and some of their properties were studied. In the present paper we continue this study further by introducing the definitions of the operators 'take' and 'drop' from the new direction and establish many properties of lists based on them. Also, the corresponding fuzzy concepts have been defined and some results are established. © 2004 Elsevier Inc. All rights reserved.

On some properties of lists and fuzzy lists

The study of tissue P systems was initiated in [6], inspired from the way neurons cooperate, processing impulses in the complex net established by synapses. These systems use multisets of objects for processing, and it was shown that computational completeness can be achieved using a small number of cells and states. In this paper, we use string objects as the underlying data structure. The control structure used is a restricted form of contextual rules and rewriting rules. We obtain two characterizations of recursively enumerable languages using these systems: tP systems having 2 states and 2 cells as well as tP systems having 4 states and a single cell generate all recursively enumerable languages. We also discuss the relationships with ET0L and E0L languages. © Springer-Verlag Berlin Heidelberg 2003.

Tissue P systems with contextual and rewriting rules

In this paper, we introduce some new variants of contextual grammars and investigate their generative power. We consider a restricted version of depth-first contextual grammars, which depends on length of the inserting contexts. Using this variant, we give a solution to the open problem P14 listed in [8]. We also introduce random context contextual grammars and compare its generative power with the families IC, ICC, EC, ECC, TC. Time-varying contextual grammars are introduced which resemble time-varying grammars. We compare the generative power of this variant with the families of internal, external, total, matrix, and programmed contextual grammars.

International Journal of Computer Mathematics

On some classes of contextual grammars

We consider P Systems with string objects which evolve by means of one-sided contextual rules and erasing contextual rules. The generative power of these systems with three or less than three membranes is investigated. We show that systems with three membranes characterize the family of recursively enumerable languages. When the string replication is used in one-sided contextual rules, these systems are able of solving NP-complete problems in linear time: this is exemplified with SAT and HPP.