An improved form of the artificial diffusion parameter-X

Artificial diffusion mechanisms used to damp post-shock oscillations or to stabilize the computations contain a factor chi which determines the amount of diffusion provided. This paper suggests an improved procedure which consists of (1) varying chi from point to point depending on the local Courant number and (2) employing a value of local chi sub i which is determined from a monotonicity analysis. Results obtained by employing a locally dependent value of chi are compared with those for a global value of ch

Modeling On-Line Art Auction Dynamics Using Functional Data Analysis

In this paper, we examine the price dynamics of on-line art auctions of modern Indian art using functional data analysis. The purpose here is not just to understand what determines the final prices of art objects, but also the price movement during the entire auction. We identify several factors, such as artist characteristics (established or emerging artist; prior sales history), art characteristics (size; painting medium--canvas or paper), competition characteristics (current number of bidders; current number of bids) and auction design characteristics (opening bid; position of the lot in the auction), that explain the dynamics of price movement in an on-line art auction. We find that the effects on price vary over the duration of the auction, with some of these effects being stronger at the beginning of the auction (such as the opening bid and historical prices realized). In some cases, the rate of change in prices (velocity) increases at the end of the auction (for canvas paintings and paintings by established artists). Our analysis suggests that the opening bid is positively related to on-line auction price levels of art at the beginning of the auction, but its effect declines toward the end of the auction. The order in which the lots appear in an art auction is negatively related to the current price level, with this relationship decreasing toward the end of the auction. This implies that lots that appear earlier have higher current prices during the early part of the auction, but that effect diminishes by the end of the auction. Established artists show a positive relationship with the price level at the beginning of the auction. Reputation or popularity of the artists and their investment potential as assessed by previous history of sales are positively related to the price levels at the beginning of the auction. The medium (canvas or paper) of the painting does not show any relationship with art auction price levels, but the size of the painting is negatively related to the current price during the early part of the auction. Important implications for auction design are drawn from the analysis.Comment: Published at http://dx.doi.org/10.1214/088342306000000196 in the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Disambiguation of Super Parts of Speech (or Supertags): Almost Parsing

In a lexicalized grammar formalism such as Lexicalized Tree-Adjoining Grammar (LTAG), each lexical item is associated with at least one elementary structure (supertag) that localizes syntactic and semantic dependencies. Thus a parser for a lexicalized grammar must search a large set of supertags to choose the right ones to combine for the parse of the sentence. We present techniques for disambiguating supertags using local information such as lexical preference and local lexical dependencies. The similarity between LTAG and Dependency grammars is exploited in the dependency model of supertag disambiguation. The performance results for various models of supertag disambiguation such as unigram, trigram and dependency-based models are presented.Comment: ps file. 8 page

Molecular communication in fluid media: The additive inverse Gaussian noise channel

We consider molecular communication, with information conveyed in the time of release of molecules. The main contribution of this paper is the development of a theoretical foundation for such a communication system. Specifically, we develop the additive inverse Gaussian (IG) noise channel model: a channel in which the information is corrupted by noise with an inverse Gaussian distribution. We show that such a channel model is appropriate for molecular communication in fluid media - when propagation between transmitter and receiver is governed by Brownian motion and when there is positive drift from transmitter to receiver. Taking advantage of the available literature on the IG distribution, upper and lower bounds on channel capacity are developed, and a maximum likelihood receiver is derived. Theory and simulation results are presented which show that such a channel does not have a single quality measure analogous to signal-to-noise ratio in the AWGN channel. It is also shown that the use of multiple molecules leads to reduced error rate in a manner akin to diversity order in wireless communications. Finally, we discuss some open problems in molecular communications that arise from the IG system model.Comment: 28 pages, 8 figures. Submitted to IEEE Transactions on Information Theory. Corrects minor typos in the first versio

The Conflict Between the Ideal and the Real in the Context of Globalization

One of the consequences of globalization appears to be a radical shift in our traditional value systems. Our identities as human beings are no longer defined by our religions or cultures, but are generalized as a global identity. This new global identity emphasizes the material self-sufficiency of individuals. The dignity of the ‘human being’ is reduced to the level of a ‘consumer’, and our values are redefined in accordance with the requirements of global community. Increasingly, it is scientific realism that guides our value system. This robs human beings of their moral freedom, and the possibility of a meaningful and purposeful life. In this paper an attempt is made to show how scientific realism can be balanced with a recovered philosophical idealism in order to prevent the continued deterioration in the quality of human life

Process of Risk Management

Cost saving and timely performance are of utmost importance to all stakeholders who are involved in a construction project that is owner, contractor, consultant and subcontractor. The prime causes of risks in construction projects involve delay and failure to complete the work at specified cost and within the agreed time frame. Unexpected delays in construction projects are caused by internal and external environments embedding several risk factors which may occur concurrently. The cost overrun and schedule overrun not only influence the construction industry’s completion of a project but can also have profound effect on the economy of a country. Even though the failure of the construction projects to get completed within the budgeted cost and time has received attention by researchers, lot more need to be researched as to what can be done to have tight leash on construction projects so that they can be brought on track. In order to meet the stiff deadlines involving complexity of construction projects, the scheduling of projects should be flexible enough to accommodate changes without negatively affecting the overall project cost and duration. This chapter deals with Perspectives on Risk Assessment and Management Paradigms as applicable to any project in general and construction industry in particular

CONTEMPORARY INDIAN APPROACHES TO EPISTEMOLOGY WITH SPECIAL REFERENCE TO B. K. MATILAL

Epistemology is one of the oldest branches of philosophy that is basically concerned with the scope and aim of knowledge, the means of knowledge, and the justification of knowledge. There are instances in the Western tradition where philosophy is reduced to mere epistemology. But there are also systems or schools of thought that balance epistemology with metaphysics. For my present study I have chosen one of the most distinguished contemporary Indian philosophers, B.K. Matilal. I propose to discuss how he understands this balance