Showing papers by "University of the Aegean published in 1994"
TL;DR: In this paper, the static dipole (α) and quadrupole (C ) polarizability and the first (β) and second (γ) dipole hyperpolarizability of methane were calculated at the SDQ-MP4 level.
75 citations
TL;DR: In this article, the probability distribution of rain rate is modeled as a temporally homogeneous diffusion process with appropiate boundary conditions, and a new parametric family is fitted to tropical rainfall from Darwin and Florida, and it is found that the lognormal distribution provides adequate fits as compared with other members of the family.
Abstract: A systematic approach is suggested for modeling the probability distribution of rain rate. Rain rate, conditional on rain and averaged over a region, is modeled as a temporally homogeneous diffusion process with appropiate boundary conditions. The approach requires a drift coefficient-conditional average instantaneous rate of change of rain intensity-as well as a diffusion coefficient-the conditional average magnitude of the rate of growth and decay of rain rate about its drift. Under certain assumptions on the drift and diffusion coefficients compatible with rain rate, a new parametric family-containing the lognormal distribution-is obtained for the continuous part of the stationary limit probability distribution. The family is fitted to tropical rainfall from Darwin and Florida, and it is found that the lognormal distribution provides adequate fits as compared with other members of the family and also with the gamma distribution.
42 citations
01 Jan 1994
TL;DR: In this article, a systematic approach is suggested for modeling the probability distribution of rain rate, conditional on rain and averaged over a region, is modeled as a temporally homogeneous diffusion process with appropriate boundary conditions.
Abstract: A systematic approach is suggested for modeling the probability distribution of rain rate. Rain rate, conditional on rain and averaged over a region, is modeled as a temporally homogeneous diffusion process with appropriate boundary conditions. The approach requires a drift coefficient-conditional average instantaneous rate of change of rain intensity − as well as a diffusion coefficient − the conditional average magnitude of the rate of growth and decay of rain rate about its drift. Under certain assumptions on the drift and diffusion coefficients compatible with rain rate, a new parametric family − containing the lognormal distribution − is obtained for the continuous part of the stationary limit probability distribution
40 citations
TL;DR: The SECURENET system is introduced, an experimental intrusion detection intelligent system, which incorporates the use of expert systems, neural networks, and intent specification languages and is presented as the basis of a reaction- time delay analysis for SECURenET in a typical WAN environment.
37 citations
TL;DR: This approach is compatible with multicriteria methods applied on policy-making and therefore the problem of eutrophication can be integrated with plan and project evaluation in environmental management.
Abstract: Multicriteria choice-methods, often used in policy analysis, were examined as a methodological procedure for eutrophication assessment. Multicriteria analysis ranked the sampling sites along two coastal areas, according to nutrient and chlorophyll concentrations. Three levels of nutrient loading were revealed, characterizing eutrophic, mesotrophic and oligotrophic waters. These results have been compared to station grouping based on multivariate analysis which indicated similar trends. Multicriteria choice-methods were shown to be an effective methodological tool in assessing eutrophication. In addition, this approach is compatible with multicriteria methods applied on policy-making and therefore the problem of eutrophication can be integrated with plan and project evaluation in environmental management.
35 citations
TL;DR: In this paper, the authors construct a general equilibrium optimization model that is capable of generating artificial (model) data for savings and investment, and then, using the methodology of cointegration testing on these artificial data, they test whether there exists or not any link between saving and investment.
35 citations
TL;DR: In this article, a discussion of power-law inflation in higher-order gravity theories using the conformal equivalence theorem is presented, and a perturbation analysis is performed to show that the powerlaw solutions are stable against homogeneous and isotropic perturbations.
Abstract: We present a discussion of power-law inflation in higher-order gravity theories Using the conformal equivalence theorem, we find power-law solutions in the context of pure higher-order gravity theories in arbitrary dimension We also find a family of polar inflationary solutions We give a perturbation analysis which establishes that the power-law solutions are stable against homogeneous and isotropic perturbations but that the polar solutions are not
20 citations
TL;DR: In this article, the authors investigate differences in the structure of the purchasing function of enterprises buying different products and operating under different degrees of state control and propose four composite parameters for measuring the articulation, formalization, depth of analysis, and decentralization of a purchasing function.
20 citations
01 May 1994-Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering
TL;DR: A methodological procedure for assessing environmental quality based on numerical classification of outlying observations is presented in this paper, which is applied to evaluate the eutrophication levels along a coastal area; four variables related to eUTrophication (nitrate, ammonia, phosphate and chlorophyll a) were analyzed.
Abstract: A methodological procedure for assessing environmental quality based on numerical classification of outlying observations is presented. The procedure was applied to evaluate the eutrophication levels along a coastal area; four variables related to eutrophication (nitrate, ammonia, phosphate and chlorophyll a) were analyzed. Outlying observations were detected and used for numerical classification of sampling sites. The existence of discontinuities between areas with different nutrient loadings was confirmed and discrete states among sampling sites were shown. It is suggested that outliers can be used as a sensitive tool for assessing water quality in coastal management studies, requiring discrete differences for decision‐making.
15 citations
TL;DR: Simulation results show the superiority of the proposed algorithm over a tracker employing the extended Kalman filter, derived using the multimodel partitioning approach.
Abstract: The problem of target tracking using passive sensors is examined. The target is assumed to execute maneuvers at times unknown to the observer. An adaptive algorithm, which takes into account such maneuvers, is derived using the multimodel partitioning approach. Simulation results show the superiority of the proposed algorithm over a tracker employing the extended Kalman filter. >
13 citations
TL;DR: These wormholes, under a conformal transformation, may be regarded as instanton-type solutions in higher order gravity with a Lagrangian that is an arbitrary analytic function of the scalar curvature.
Abstract: We examine conditions for the existence of wormhole solutions in the Einstein equations with a dynamical minimally coupled scalar field matter source with an arbitrary effective potential. We find three wormhole solutions which connect a baby universe with two asymptotically flat spaces through a narrow tube in a constant, cosinelike, and $\ensuremath{\Sigma}{i=0}^{3}{c}_{i}{a}^{\ensuremath{-}i}$ potential, respectively ($a$ being the scale factor). Because of the fact that the scalar field is not constant inside these wormholes, the gravitational constant takes different values in the two asymptotically flat spaces. These wormholes, under a conformal transformation, may be regarded as instanton-type solutions in higher order gravity with a Lagrangian that is an arbitrary analytic function of the scalar curvature.
TL;DR: In this paper, modifications of the original axioms of Menger were considered, which together with additional axiomatizations characterize the covering dimension, dim, on the class of metrizable spaces.
TL;DR: In this paper, a detailed probabilistic treatment based on the Fokker-Planck equation is given for the self-regenerating mechanism in higher order gravity theories.
Journal Article•
TL;DR: Because of the increasing role of information technology in health care more attention is needed for security, and a high level security policy needs to be formulated for each institution.
Abstract: Because of the increasing role of information technology in health care more attention is needed for security. Legal, technical/organisational and social measures are needed. Based on general principles a high level security policy needs to be formulated for each institution. Based on such policy measures can be selected and implemented. The need for a high level policy is emphasized; as an example the high level policy developed within the AIM SEISMED project is briefly described.
01 Jan 1994
TL;DR: In this article, a connected Lie group with co-compact radical G is considered and the invariant integral of ϕ relative to the Cartan subgroup G(l) of G is derived.
Abstract: We consider a connected Lie group with co-compact radical G. Let g be the Lie algebra of G. Let 1 be in the dual of g. Under the assumption that g(l) is commutative and reductive in g,we construct an application ϕ → Fl,ϕ from D(G) to the space of C∞functions on an open dense subset of G(l). If G is compact, Fl,ϕ is — up to a scalar — the invariant integral of ϕ relative to the Cartan subgroup G(l) of G. Using this, we obtain a formula for the trace of the operator T(l, G)(ϕ), where T(l, G) is the unitary representation of G associated to l.
Posted Content•
TL;DR: In this paper, the authors propose an anasynthesis of these approaches, in the base of the "milieu" terms, which can examine the interactions between the productive, the social and the environmental systems in their territorial continuity.
Abstract: The multiform reproduction of the crisis in Southern Europe, considering its contemporary aspects, strongly demands a new theoretical approach orientated to its structural substances. In fact, the contributions of the “ecole de la regulation” seem to supply the fertile basis for a renewal in the analysis of the crisis, which can deepen in the dimension of its historical specification and its “synthetic” social content, working in terms of harmony and disharmony inside of forms of social – economic regulation – accumulation. On the other hand, the conception of investment dynamics, in terms of the global system, gives the opportunity to comprehend the word wide development dynamics through their structural expressions: those expressions can integrate the dialectic configuration of firm strategies and national politics. Finally, our description proposes an effort towards an anasynthesis of these approaches, in the base of the “milieu” terms, which can examine the interactions between the productive, the social and the environmental systems – in their territorial continuity. This systemic unity seems to determine the development trajectories and crisis – as they are expressed by the presense or absence of an internal equilibrium – in the common field of the reproduction between the investment strategies (internals – externals) the regulation mechanisms and the spatial – social entities.
TL;DR: In this paper, the existence of equivariant endomorphisms of a flat crystallographic manifold was shown to expand distances in certain directions transverse to the fibers of the map MΓ→MΔ, where Ac is the sum of all 1-dimensional G-submodules of the manifold.
07 Sep 1994
TL;DR: The raw performance and facility levels will be of little benefit without the means to deploy the capacity in line with a wide spectrum of demands spanning 9 bulk commitments for, say, delivery of cable-tv and on-demand video, 9 high instantly available bandwidth for virtual private networks, 9 absolute priority needs of emergency services, 9 and so on down to the humble phone conversation or public electronic mail service.
TL;DR: In this article, the Radom-Nikodým property has been studied for weakly compact subsets of L 1(μ, X) and bvca(Σ, X).
Abstract: In this paper we study the weakly compact subset ofL 1(μ,X) and bvca(Σ,X), supposing that proper subsets ofX andX * have the Radom-Nikodým property.
TL;DR: In this paper, the existence of optimal solutions for a very general optimal economic growth problem with unbounded planning time horizon is examined and sensitivity analysis is conducted to determine the relation between optimal pairs and the initial capital accumulation.