Abstract: In this paper, a delayed physiological control system is investigated. The sufficient conditions for stability of positive equilibrium and existence of local Hopf bifurcation are derived. Furthermore, global existence of periodic solutions is established by using the global Hopf bifurcation theory. Finally, numerical examples are given to support the theoretical analysis.
Abstract: Creep stresses and strain rates have been obtained
for a thin rotating disc having variable density with inclusion by
using Seth-s transition theory. The density of the disc is assumed to
vary radially, i.e. ( ) 0 ¤ü ¤ü r/b m - = ; ¤ü 0 and m being real positive
constants. It has been observed that a disc, whose density increases
radially, rotates at higher angular speed, thus decreasing the
possibility of a fracture at the bore, whereas for a disc whose
density decreases radially, the possibility of a fracture at the bore
increases.
Abstract: In a product development process, understanding the functional behavior of the system, the role of components in achieving functions and failure modes if components/subsystem fails its required function will help develop appropriate design validation and verification program for reliability assessment. The integration of these three issues will help design and reliability engineers in identifying weak spots in design and planning future actions and testing program. This case study demonstrate the advantage of unascertained theory described in the subjective cognition uncertainty, and then applies blind number (BN) theory in describing the uncertainty of the mechanical system failure process and the same time used the same theory in bringing out another mechanical reliability system model. The practical calculations shows the BN Model embodied the characters of simply, small account of calculation but betterforecasting capability, which had the value of macroscopic discussion to some extent.
Abstract: The photonic component industry is a highly
innovative industry with a large value chain. In order to ensure the
growth of the industry much effort must be devoted to road mapping
activities. In such activities demand and price evolution forecasting
tools can prove quite useful in order to help in the roadmap
refinement and update process. This paper attempts to provide useful
guidelines in roadmapping of optical components and considers two
models based on diffusion theory and the extended learning curve for
demand and price evolution forecasting.
Abstract: Graph decompositions are vital in the study of combinatorial design theory. Given two graphs G and H, an H-decomposition of G is a partition of the edge set of G into disjoint isomorphic copies of H. An n-sun is a cycle Cn with an edge terminating in a vertex of degree one attached to each vertex. In this paper we have proved that the complete graph of order 2n, K2n can be decomposed into n-2 n-suns, a Hamilton cycle and a perfect matching, when n is even and for odd case, the decomposition is n-1 n-suns and a perfect matching. For an odd order complete graph K2n+1, delete the star subgraph K1, 2n and the resultant graph K2n is decomposed as in the case of even order. The method of building n-suns uses Walecki's construction for the Hamilton decomposition of complete graphs. A spanning tree decomposition of even order complete graphs is also discussed using the labeling scheme of n-sun decomposition. A complete bipartite graph Kn, n can be decomposed into n/2 n-suns when n/2 is even. When n/2 is odd, Kn, n can be decomposed into (n-2)/2 n-suns and a Hamilton cycle.
Abstract: In the present work, an attempt is made to understand
electromagnetic field confinement in a subwavelength waveguide
structure using concepts of quantum mechanics. Evanescent field in
the waveguide is looked as inability of the photon to get confined in
the waveguide core and uncertainty of position is assigned to it. The
momentum uncertainty is calculated from position uncertainty.
Schrödinger wave equation for the photon is written by incorporating
position-momentum uncertainty. The equation is solved and field
distribution in the waveguide is obtained. The field distribution and
power confinement is compared with conventional waveguide theory.
They were found in good agreement with each other.
Abstract: Oxygen transfer, the process by which oxygen is
transferred from the gaseous to liquid phase, is a vital part of the
waste water treatment process. Because of low solubility of
oxygen and consequent low rate of oxygen transfer, sufficient
oxygen to meet the requirement of aerobic waste does not enter
through normal surface air water interface. Many theories have
come up in explaining the mechanism of gas transfer and
absorption of non-reacting gases in a liquid, of out of which, Two
film theory is important. An exiting mathematical model
determines approximate value of Overall Gas Transfer coefficient.
The Overall Gas Transfer coefficient, in case of Penetration theory,
is 1.13 time more than that obtained in case of Two film theory.
The difference is due to the difference in assumptions in the two
theories.
The paper aims at development of mathematical model which
determines the value of Overall Gas Transfer coefficient with
greater accuracy than the existing model.
Abstract: This paper studies dynamic stability of homogeneous
beams with piezoelectric layers subjected to periodic axial
compressive load that is simply supported at both ends lies on a
continuous elastic foundation. The displacement field of beam is
assumed based on Bernoulli-Euler beam theory. Applying the
Hamilton's principle, the governing dynamic equation is established.
The influences of applied voltage, foundation coefficient and
piezoelectric thickness on the unstable regions are presented. To
investigate the accuracy of the present analysis, a compression study
is carried out with a known data.
Abstract: Air bubbles have been detected in human circulation
of end-stage renal disease patients who are treated by hemodialysis.
The consequence of air embolism, air bubbles, is under recognized
and usually overlooked in daily practice. This paper shows results of
a capacitor based detection method that capable of detecting the
presence of air bubbles in the blood stream in different frequencies.
The method is based on a parallel plates capacitor made of platinum
with an area of 1.5 cm2 and a distance between the two plates is 1cm.
The dielectric material used in this capacitor is Dextran70 solution
which mimics blood rheology. Simulations were carried out using
RC circuit at two frequencies 30Hz and 3 kHz and results compared
with experiments and theory. It is observed that by injecting air
bubbles of different diameters into the device, there were significant
changes in the capacitance of the capacitor. Furthermore, it is
observed that the output voltage from the circuit increased with
increasing air bubble diameter. These results demonstrate the
feasibility of this approach in improving air bubble detection in
Hemodialysis.
Abstract: Computer languages are usually lumped together
into broad -paradigms-, leaving us in want of a finer classification
of kinds of language. Theories distinguishing between -genuine
differences- in language has been called for, and we propose that
such differences can be observed through a notion of expressive mode.
We outline this concept, propose how it could be operationalized and
indicate a possible context for the development of a corresponding
theory. Finally we consider a possible application in connection
with evaluation of language revision. We illustrate this with a case,
investigating possible revisions of the relational algebra in order to
overcome weaknesses of the division operator in connection with
universal queries.
Abstract: With the enormous growth on the web, users get easily
lost in the rich hyper structure. Thus developing user friendly and
automated tools for providing relevant information without any
redundant links to the users to cater to their needs is the primary task
for the website owners. Most of the existing web mining algorithms
have concentrated on finding frequent patterns while neglecting the
less frequent one that are likely to contain the outlying data such as
noise, irrelevant and redundant data. This paper proposes new
algorithm for mining the web content by detecting the redundant
links from the web documents using set theoretical(classical
mathematics) such as subset, union, intersection etc,. Then the
redundant links is removed from the original web content to get the
required information by the user..
Abstract: Probabilistic techniques in computer programs are becoming
more and more widely used. Therefore, there is a big
interest in the formal specification, verification, and development
of probabilistic programs. In our work-in-progress project, we are
attempting to make a constructive framework for developing probabilistic
programs formally. The main contribution of this paper
is to introduce an intermediate artifact of our work, a Z-based
formalism called PZ, by which one can build set theoretical models of
probabilistic programs. We propose to use a constructive set theory,
called CZ set theory, to interpret the specifications written in PZ.
Since CZ has an interpretation in Martin-L¨of-s theory of types, this
idea enables us to derive probabilistic programs from correctness
proofs of their PZ specifications.
Abstract: We discuss a theoretical conceptual framework to help
understand how the new business analytics technologies have
diffused in firms. We draw on three theoretical perspectives for this
purpose. They are innovation diffusion theory, IT Business Value
and the technology-organization-environment theory. We develop a
conceptual framework that helps understand the interlinkages among
factors affecting diffusion of business analytics and its impact on
performance.
Abstract: This work deals with the initial applications and formulation of an anisotropic plastic-damage constitutive model proposed for non-linear analysis of reinforced concrete structures submitted to a loading with change of the sign. The original constitutive model is based on the fundamental hypothesis of energy equivalence between real and continuous medium following the concepts of the Continuum Damage Mechanics. The concrete is assumed as an initial elastic isotropic medium presenting anisotropy, permanent strains and bimodularity (distinct elastic responses whether traction or compression stress states prevail) induced by damage evolution. In order to take into account the bimodularity, two damage tensors governing the rigidity in tension or compression regimes are introduced. Then, some conditions are introduced in the original version of the model in order to simulate the damage unilateral effect. The three-dimensional version of the proposed model is analyzed in order to validate its formulation when compared to micromechanical theory. The one-dimensional version of the model is applied in the analyses of a reinforced concrete beam submitted to a loading with change of the sign. Despite the parametric identification problems, the initial applications show the good performance of the model.
Abstract: The uniform Roe C*-algebra (also called uniform translation)C^*- algebra provides a link between coarse geometry and C^*- algebra theory. The uniform Roe algebra has a great importance in geometry, topology and analysis. We consider some of the elementary concepts associated with coarse spaces.
Abstract: Influence diagrams (IDs) are one of the most commonly used graphical decision models for reasoning under uncertainty. The quantification of IDs which consists in defining conditional probabilities for chance nodes and utility functions for value nodes is not always obvious. In fact, decision makers cannot always provide exact numerical values and in some cases, it is more easier for them to specify qualitative preference orders. This work proposes an adaptation of standard IDs to the qualitative framework based on possibility theory.
Abstract: The interrelationship between international stock
markets has been a key study area among the financial market
researchers for international portfolio management and risk
measurement. The characteristics of security returns and their
dynamics play a vital role in the financial market theory. This study
is an attempt to find out the dynamic linkages among the equity
market of USA and emerging markets of Pakistan and India using
daily data covering the period of January 2003–December 2009. The
study utilizes Johansen (Journal of Economic Dynamics and Control,
12, 1988) and Johansen and Juselius (Oxford Bulletin of Economics
and Statistics, 52, 1990) cointegration procedure for long run
relationship and Granger-causality tests based on Toda and
Yamamoto (Journal of Econometrics, 66, 1995) methodology.
No cointegration was found among stock markets of USA, Pakistan
and India, while Granger-causality test showed the evidence of
unidirectional causality running from New York stock exchange to
Bombay and Karachi stock exchanges.
Abstract: This paper presents the elastic buckling of
homogeneous beams with a pair of piezoelectric layers surface
bonded on both sides of the beams. The displacement field of beam is
assumed based on the Engesser-Timoshenko beam theory.
Applying the Hamilton's principle, the equilibrium equation is
established. The influences of applied voltage, dimensionless
geometrical parameter and piezoelectric thickness on the critical
buckling load of beam are presented. To investigate the accuracy of
the present analysis, a compression study is carried out with a known
data.
Abstract: The majority of existing predictors for time series are
model-dependent and therefore require some prior knowledge for the
identification of complex systems, usually involving system
identification, extensive training, or online adaptation in the case of
time-varying systems. Additionally, since a time series is usually
generated by complex processes such as the stock market or other
chaotic systems, identification, modeling or the online updating of
parameters can be problematic. In this paper a model-free predictor
(MFP) for a time series produced by an unknown nonlinear system or
process is derived using tracking theory. An identical derivation of the
MFP using the property of the Newton form of the interpolating
polynomial is also presented. The MFP is able to accurately predict
future values of a time series, is stable, has few tuning parameters and
is desirable for engineering applications due to its simplicity, fast
prediction speed and extremely low computational load. The
performance of the proposed MFP is demonstrated using the
prediction of the Dow Jones Industrial Average stock index.
Abstract: A model of vortex wake is suggested to determine the
induced power during animal hovering flight. The wake is modeled
by a series of equi-spaced rigid rectangular vortex plates, positioned
horizontally and moving vertically downwards with identical speeds;
each plate is generated during powering of the functionally wing
stroke. The vortex representation of the wake considered in the
current theory allows a considerable loss of momentum to occur. The
current approach accords well with the nature of the wingbeat since it
considers the unsteadiness in the wake as an important fluid
dynamical characteristic. Induced power in hovering is calculated as
the aerodynamic power required to generate the vortex wake system.
Specific mean induced power to mean wing tip velocity ratio is
determined by solely the normal spacing parameter (f) for a given
wing stroke amplitude. The current theory gives much higher specific
induced power estimate than anticipated by classical methods.