bluuebunny/crossref_metadata_2025 huggingface dataset:
STERILIZATION OF CANNED VISCOUS FOODS: AN OPTIMAL CONTROL APPROACH
Authors: ALVAREZ-VAZQUEZ L. J. , MARTA M. , MARTINEZ A.
Published: March 2004

In this paper, we study an optimal control problem with pointwise constraints on state and control, related to sterilization processes involving heat transfer by natural convection. We introduce the mathematical model for the state system, which couples the Boussinesq system for temperature-dependent viscosity and the convection-reaction-diffusion equations, and we set the whole problem as a control problem, assuring the micro-organism reduction, the nutrient retention and the energy saving. The existence and the regularity of the state are studied. Finally, we obtain existence results for the optimal solutions and a first-order optimality condition for their characterization.
CONVERGENCE RESULTS FOR A PHASE TRANSITION MODEL WITH VANISHING MICROSCOPIC ACCELERATION
Authors: BONFANTI GIOVANNA , LUTEROTTI FABIO
Published: March 2004

A recent phase transition model, proposed by Frémond, is based on the consideration that the microscopic movements are responsible for the phase transition at the macroscopic level. A last version of the model, accounting also for the microscopic accelerations has been investigated in Ref. 4, where well-posedness results are established for related Cauchy–Neumann problems. The aim of this paper is the study of the asymptotic behavior of the solution to one of the above problems, as the power of the microscopic acceleration forces goes to zero.
ASYMPTOTIC EXPANSION AND CONVERGENCE THEOREM OF CONTROL AND OBSERVATION ON THE BOUNDARY FOR SECOND-ORDER ELLIPTIC EQUATION WITH HIGHLY OSCILLATORY COEFFICIENTS
Authors: CAO LI-QUN
Published: March 2004

In this paper, we shall study systems governed by the Neumann problem of second-order elliptic equation with rapidly oscillating coefficients and with control and observations on the boundary. The multiscale asymptotic expansions of the solution for considering problem in the case without any constraints, and homogenized equation in the case with constraints will be given, their rigorous proofs will also be proposed.
SLIP-WEAKENING FRICTION INSTABILITIES: EIGENVALUE ANALYSIS
Authors: DASCALU CRISTIAN , IONESCU IOAN R.
Published: March 2004

We consider the evolution problem for the wave equation with nonlinear boundary conditions, modeling the anti-plane shearing on a system of finite faults under a slip-dependent friction in a linear elastic continuum. The associated eigenvalue problem is studied for bounded and unbounded domains. Recent studies showed that this eigenvalue problem plays a key role in earthquake nucleation modeling. We investigate the structure of the positive eigenvalues set and prove the monotone dependence of the first eigenvalue on the friction parameter. For the elastic plane with a collinear system of faults, the eigenvalue problem is reduced to a hyper-singular integral equation. This equation is solved through a semi-analytical technique. Numerical results show a sensible dependence of the first eigenfunction on the geometry and friction heterogeneity.
NUCLEAR ALPHA-CLUSTERING, SUPERDEFORMATION, AND QUASIMOLECULAR RESONANCES
Authors: BECK C.
Published: March 2004

Nuclear alpha-clustering has been the subject of intense study since the advent of heavy-ion accelerators. Looking back for more than 40 years we are able today to see the connection between quasimolecular resonances in heavy-ion collisions and extremely deformed states in light nuclei. For example superdeformed bands have been recently discovered in light N=Z nuclei such as 36 Ar , 40 Ca , 48 Cr , and 56 Ni by γ-ray spectroscopy. The search for strongly deformed shapes in N=Z nuclei is also the domain of charged-particle spectroscopy, and a number of these nuclei have been studied with the charged particle multidetector array ICARE at the VIVITRON. Recently the search for γ-decays in 24 Mg has been undertaken in a range of excitation energies where previously nuclear molecular resonances were found in 12 C +12 C collisions. The breakup reaction 24 Mg +12 C has been investigated at an energy which corresponds to a 12 C +12 C resonance. Very exclusive data were collected with the Binary Reaction Spectrometer in coincidence with EUROBALL IV installed at the VIVITRON. Results on the population of specific structures of large deformation will be presented.
HIGH-SPIN STRUCTURE OF NEUTRON-RICH NUCLEI PRODUCED BY HEAVY-ION INDUCED FISSION
Authors: PORQUET M.-G.
Published: March 2004

Using the Euroball array, we have recently performed several experiments devoted to the study of high-spin states of nuclei with A~80–130, produced from fission following various fusion reactions. High-spin level schemes of many neutron-rich nuclei have been extended or newly established. We present here the new experimental results obtained in some neutron-rich odd-Z nuclei from 43 Tc to 49 In . All the band-head configurations have been identified from the behaviour of the collective bands built on them. Therefore the single-proton states, located around the Fermi levels for Z=43 to 49, can be discussed as a function of the neutron number (and the deformation). In all these isotopic series, three-quasiparticle states have been measured above 2 MeV excitation energy. The case of 49 In nuclei is discussed in the framework of shell-model calculations. Futhermore the individual identification of each fragment by means of its emitted γ transitions allows us to have a new insight into the mechanism of fission induced by heavy ions. Preliminary results of the total number of emitted neutrons are discussed as a function of the N/Z ratios of the fragments.
REMARKS ON SYMMETRIES OF GENERALIZED ROTOR SPACE
Authors: GÓŹDŹ A. , MIŚKIEWICZ M. , OLSZEWSKI A.
Published: March 2004

We propose methods of analysis of the symmetries of the rotor space. A few examples of the point symmetries and their consequences for the state space of the quantum rotors are shortly considered.
PRE-EQUILIBRIUM CLUSTER EMISSION
Authors: BĚTÁK E.
Published: March 2004

We present pre-equilibrium models of cluster (deuterons to alphas) emission from reactions induced by light projectiles at energies below the pion threshold. The main attention is given to the hard components of the emission spectra. The pre-equilibrium mechanisms of cluster emission show a kind of competition between pickup and knockout reactions in some cases, in addition to the classical coalescence. We discuss the processes in force and the interplays of competing mechanisms.
COULOMB EXCITATION OF 150Nd
Authors: ZIELIŃSKA MAGDALENA
Published: March 2004

The nucleus 150 Nd was Coulomb excited using 14 N , 58 Ni and 92 Mo beams. The overall result of the experiments performed consists of 780 measured gamma yields, which combined with available spectroscopic data gave about 800 data points to overdetermine the set of matrix elements needed to describe the observed processes. A number of E1, E2 and E3 matrix elements coupling the low-lying states has been determined in a model-independent way. In addition, an influence of E4 moments, competing with double E2 excitations, was tested with the low energy 14 N beam. Possible interpretations of the unusual electromagnetic structure found experimentally may pose the challenge to the theorists.
A NEW PARAMETER SET FOR THE RELATIVISTIC MEAN FIELD THEORY
Authors: NERLO-POMORSKA BOŻENA , SYKUT JOANNA
Published: March 2004

Subtracting the Strutinsky shell corrections from the selfconsistent energies obtained within the Relativistic Mean Field Theory (RMFT) we have got estimates for the macroscopic part of the binding energies of 142 spherical even-even nuclei. By minimizing their root-mean-square deviations from the values obtained with the Lublin-Srasbourg Drop (LSD) model with respect to the nine RMFT parameters we have found the optimal set (NL4). The new parameters reproduce also the radii of these nuclei with an accuracy comparable to that obtained with the NL1 and NL3 sets.
STRUCTURE OF SUPERHEAVY NUCLEI WITH THE GOGNY FORCE
Authors: BERGER J. F. , HIRATA D. , GIROD M. , DECHARGE J.
Published: March 2004

This contribution summarizes the predictions obtained in the domain of superheavy nuclei from self-consistent microscopic calculations employing the Gogny force. Results concerning shell gaps, fission barriers and stability against alpha-decay are recalled. Recent work involving α-decay chains in odd nuclides is also presented and discussed.
THE NUCLEAR MASS AT FINITE ANGULAR MOMENTA
Authors: RAGNARSSON INGEMAR , KONDEV FILIP G. , PAUL EDWARD S. , RILEY MARK A. , SIMPSON JOHN
Published: March 2004

The definition of experimental shell energies for nuclear ground states is generalized to finite angular momenta corresponding to a systematic expansion of the (N,Z)-plane to an (N,Z,I) space. Special emphasis is put on high-spin states where it is expected that odd and even nuclei should have similar properties. Different coupling schemes are compared and energetically favoured conditions to build high-spin states are discussed.
δ-PAIRING FORCES AND NUCLEAR MASSES
Authors: BARAN A. , SIEJA K.
Published: March 2004

The δ-pairing strengths for rare-earth nuclei are estimated from nuclear masses of odd and even systems. The masses are calculated for a variety of macroscopic and microscopic models. We use the BCS and Lipkin-Nogami methods, with a blocking effect in case of odd nuclei. The rms mass deviations obtained in different models are from 0.66 to 1.46.
COMPETITION BETWEEN AXIAL AND NON-AXIAL OCTUPOLE DEFORMATIONS IN HEAVY NUCLEI
Authors: DUDEK J. , MAZUREK K. , NERLO-POMORSKA B.
Published: March 2004

The macroscopic-microscopic method is applied to calculate the energies of heavy nuclei (A>220) in a multidimensional deformation space {αλ,μ} including axial and non-axial quadrupole (λ=2,μ=0,2), axial and non-axial octupole (λ=3,μ=0,2) and axial hexadecapole (λ=4,μ=0) degrees of freedom. Shell and pairing corrections are calculated from the single-particle energies of the Woods-Saxon potential with the universal parameters and added to the macroscopic energy of the newest Lublin-Strasbourg Drop (LSD) model to obtain the total deformation energy.
STRUCTURE OF NEUTRON–RICH NUCLEI FROM DEEP–INELASTIC REACTIONS
Authors: PODOLYÁK Zs. , MOHAMMADI S. , DE ANGELIS G. , ZHANG Y. H. , AXIOTIS M. , BAZZACCO D. , BIZZETI P. G. , BRANDOLINI F. , BRODA R. , BUCURESCU D. , FARNEA E. , GELLETLY W. , GADEA A. , IONESCU-BUJOR M. , IORDACHESCU A. , KRÖLL Th. , LANGDOWN S. D. , LUNARDI S. , MARGINEAN N. , MARTINEZ T. , MEDINA N. H. , QUINTANA B. , REGAN P. H. , RUBIO B. , UR C. A. , VALIENTE-DOBÓN J. J. , WALKER P. M.
Published: March 2004

Neutron rich nuclei have been populated using the 82 Se +192 Os deep-inelastic reaction. New experimental results on 188 W , 188,190 Os target-like nuclei, as well as 74,76,78 Ge beam-like nuclei are presented.
QUANTUM ROTATIONAL SPECTRA AND CLASSICAL ROTORS
Authors: MIŚKIEWICZ MAREK , GÓŹDŹ ANDRZEJ , DUDEK JERZY
Published: March 2004

We consider the generalized rotor Hamiltonians capable of describing quantum systems invariant with respect to symmetry point-groups that go beyond the usual D2-symmetry of a tri-axial rotor. We discuss the canonical de-quantisation procedure to obtain the classical analogs of the original quantum Hamiltonians. Classical and quantum solutions to the Hamiltonians relevant in the nuclear physics applications are illustrated and compared using the 'usual' (D2) and an 'exotic' (Td) symmetries.
DESCRIPTION OF SHAPE COEXISTENCE BY MEAN-FIELD AND BEYOND MEAN-FIELD METHODS
Authors: HEENEN P-H , BENDER M. , BONCHE P. , DUGUET T.
Published: March 2004

In this talk, we present a method which allows the introduction of correlations beyond a Skyrme Hartree-Fock calculation by symmetry restoration and configuration mixing on the axial quadrupole moment. A first application to 240 Pu is discussed, to show the potential of the method. As an example of the shape coexistence phenomenon in Pb isotopes, results for collective spectra and transition probabilities are then presented for 188 Pb .
STATIC AND DYNAMIC NON-AXIAL OCTUPOLE DEFORMATIONS SUGGESTED BY SKYRME-HF AND SELFCONSISTENT RPA CALCULATIONS
Authors: INAKURA T. , YAMAGAMI M. , MATSUYANAGI K. , MIZUTORI S. , IMAGAWA H. , HASHIMOTO Y.
Published: March 2004

On the basis of the symmetry-unrestricted, cranked Skyrme-Hartree-Fock (SHF) calculations, we discuss superdeformed (SD) rotational bands in (1) the 40 Ca region along the N=Z line, and (2) neutron-rich Sulfur isotopes up to the neutron-drip line. The calculation was carried out with the use of the three-dimensional (3D) coordinate-mesh representation without imposing any symmetry restriction. Stability of the SD bands against exotic deformations breaking both reflection and axial symmetries were carefully examined. The analysis indicates possible appearance of negative-parity rotational bands associated with octupole shape vibrational excitations built on the SD yrast band. We then present results of selfconsistent RPA calculation for such a new type of collective vibrational modes. The selfconsistent RPA calculations based on the SD local minima obtained by the SHF calculation were carried out by means of the mixed representation on the 3D Cartesian mesh in a box.
ON THE STABILITY OF PROJECTION AFTER VARIATION SOLUTIONS
Authors: RODRÍGUEZ T. R. , EGIDO J. L. , ROBLEDO L. M. , RODRÍGUEZ-GUZMÁN R. R.
Published: March 2004

We have performed angular momentum projection with double-constrained Hartree-Fock-Bogoliubov wave functions with the Gogny interaction for the 32 Mg . We show that the more relevant degree of freedom is the quadrupole deformation. Minima of the ground state obtained in single-constrained calculations with this operator are hardly modified in double-constrained calculations insuring thereby the stability of the solution.
GIANT RESONANCES IN EXOTIC SPHERICAL NUCLEI WITHIN THE HF+RPA APPROACH
Authors: PERU S. , BERGER J. F.
Published: March 2004

The energies and characteristics of giant resonances obtained from HF+RPA calculations with the Gogny force are derived in three doubly magic exotic nuclei. The results show a lowering of the monopole resonance energy compared to systematic values in stable nuclei, in particular in 78 Ni . The Isovector Giant Dipole Resonance (IVGDR) in the two tin isotopes appears splitted into two major peaks.
GIANT RESONANCES FROM TDHF
Authors: STEVENSON P. D. , STRAYER M. R. , RIKOVSKA STONE J. , NEWTON W. G.
Published: March 2004

A method of calculating giant resonance strength functions using Time-Dependent Hartree-Fock techniques is described. An application to isoscalar giant monopole resonances in spherical nuclei is made, thus allowing a comparison between independent 1-, 2- and 3-Dimensional computer codes.
NUCLEAR PAIRING AS RANDOM WALK OF COOPER PAIRS
Authors: DUDEK J. , FAES J. B.
Published: March 2004

We develop a stochastic approach to obtain the energies and wave functions of the full spectrum of the nuclear pairing Hamiltonian (i.e. not only the ground-state but also the excited states of the nuclear many-body systems). We assume that nuclear Cooper pairs may spontaneously jump from one energy configuration to another, the mechanism resembling that of the random walk on a mesh of non-equidistant points. A probability distribution associated with such a random walk is modelled and the resulting solutions tested using an exact quantum algorithm. We use the Hamiltonian parameters characteristic for the nuclear scale: at present an agreement between the quantum and stochastic treatment is of the order of a few permille in terms of eigen-energies.
THE RELATIVISTIC MEAN FIELD THEORY AND LOW ENERGY QUADRUPOLE COLLECTIVE EXCITATIONS
Authors: PRÓCHNIAK L. , RING P.
Published: March 2004

We present an attempt to describe low lying quadrupole collective excitations within the frame of the RMF theory. Single particle wavefunctions obtained from the RMF are used to calculate mass parameters in the cranking approximation of the ATDHFB. The general Bohr hamiltonian with the calculated mass parameters yields collective energies and wavefunctions. Theoretical results are compared with the experimental data in the case of the γ soft 110 Ru and 126 Ba nuclei.
A STOCHASTIC PARAMETRISATION OF THE SPECTRA OF THE NUCLEAR PAIRING HAMILTONIAN
Authors: MOLIQUE HERVÉ , DUDEK JERZY
Published: March 2004

In this article we present a method to parametrise the exact solutions to the nuclear pairing problem, for realistic large-scale many-body spaces. This new approach allows for rapid and quite accurate estimates of the pairing influence on the excitation energies of the nucleus, treated in the standard mean-field approximation.
DSAM LIFETIME MEASUREMENTS IN THE YRAST BAND OF 131La AND THE CHIRAL BANDS IN 132La
Authors: GRODNER E. , SREBRNY J. , DROSTE Ch. , MOREK T. , PASTERNAK A. , KOWNACKI J.
Published: March 2004

Lifetimes of the h 11/2 decoupled band in 131 La and supposed chiral bands in odd-odd 132 La have been measured using the Doppler Shift Atenuation method. The properties of all bands have been calculated in terms of the Core Quasi Particle Coupling and Core Particle Hole Coupling models by using in both cases the same phenomenological core of 130 Ba . A new band in 132 La has been found.
CALCULATIONS OF CROSS SECTIONS FOR THE SYNTHESIS OF SUPER-HEAVY NUCLEI IN COLD FUSION REACTIONS
Authors: ŚWIATECKI W. J. , SIWEK-WILCZYŃSKA K. , WILCZYŃSKI J.
Published: March 2004

The fusion cross sections are considered to be given by the product of three factors: the cross section to overcome the Coulomb barrier, the probability for the resulting system to reach the compound nucleus configuration by diffusion, and the probability for the compound nucleus to survive fission. The first and third factors are treated by more or less conventional equations, and the second by Brownian diffusion in one dimension. Adjusting one free parameter in the theory one can reproduce the twelve measured cross sections to within a factor of two.
RELATIONSHIPS BETWEEN CALORIC CURVES AND THE CRITICAL POINT OF NUCLEONIC MATTER
Authors: NATOWITZ J. B. , HAGEL K. , MA Y. , MURRAY M. , QIN L. , SHLOMO S. , WADA R. , WANG J.
Published: March 2004

Recent results on limiting temperatures and caloric curves are discussed with respect to the question of identifying critical behavior in the disassembly of nuclei. We suggest that the best candidates for exploring such behavior are light nuclei in which the Coulomb Energies are less disruptive.
ANALYTIC RESULTS ON LEVEL DENSITIES
Authors: KRAPPE H. J.
Published: March 2004

Use of the free energy in dynamical fission calculations and of the level density in simultaneous particle-evaporation yields raises the question of compatibility of these two pieces of input of quite different origin in calculations of the decay of hot compound nuclei. Seeming discrepancies between the Bethe formula for the level density and the popular assumption of a quadratic temperature dependence of the free energy are discussed in the framework of the picket-fence model, where the theory of partitions allows to calculate all thermodynamic functions analytically together with their limits for large systems and high temperature.
TRACKING DISSIPATION IN CAPTURE REACTIONS
Authors: MATERNA T. , BOUCHAT V. , KINNARD V. , HANAPPE F. , DORVAUX O. , SCHMITT C. , STUTTGÉ L. , SIWEK-WILCZYŃSKA K. , ARITOMO Y. , BOGATCHEV A. , PROKHOROVA E. , OHTA M.
Published: March 2004

Nuclear dissipation in capture reactions is investigated using backtracing. Combining the analysis procedure with dynamical models, the difficult and long-standing problem of competition and mixing of quasi-fission and fusion-fission is solved for the first time. At low excitation energy a new protocol able to handle low statistics data gives access to the prescission neutron multiplicity in two different systems 48 Ca +208 Pb, Pu . The results are in agreement with a domination of fusion-fission in the case of 256 No and an equal mixing of quasi-fission and fusion-fission in the case of Z=114. The nature of the relevant dissipation is determined as one-body dissipation.
HOW MANY FUSION BARRIERS?
Authors: SWIDERSKI L. , CZOSNYKA P. , KOWALCZYK M. , PIASECKI E. , PIASECKI K. , WITECKI M. , JASTRZȨBSKI J. , KORDYASZ A. , KISIELINSKI M. , KROGULSKI T. , ROWLEY N. , MARCHETTA C. , PAGANO A. , MUTTERER M. , TRZASKA W. H. , HAGINO K.
Published: March 2004

Fusion barrier distributions for the 20 Ne + 112,116,118 Sn systems have been extracted from quasi-elastic scattering cross sections measured at the Warsaw HIL Cyclotron. Results are compared to coupled-channels calculations performed with the CCFULL code. The overall widths of the distributions are reproduced on taking account of the low-lying collective states of the target and projectile but some puzzling discrepancies in their shapes remain to be explained.
STRUCTURAL EFFECTS IN THE NUCLIDE DISTRIBUTIONS OF THE RESIDUES OF HIGHLY EXCITED SYSTEMS
Authors: NAPOLITANI P. , REJMUND F. , TASSAN-GOT L. , RICCIARDI M. V. , KELIC A. , SCHMIDT K.-H. , YORDANOV O. , IGNATYUK A. V. , VILLAGRASA C.
Published: March 2004

New data from GSI on the production-cross-section for fragmentation of the systems 56 Fe+p and 136 Xe+p at 1 A GeV revealed the appearance of even-odd staggering in the cross-section distribution for chains of isotopes with given N-Z. The staggering is strongly enhanced for the chain N=Z, it reduces as the production moves away from the N=Z chain, and it reverses for the most neutron-rich odd-A residues. These phenomena, observed in the residues of rather violent reactions, are related to structural effects in the level-densities below the particle-emission threshold.
NEUTRON DENSITY DISTRIBUTIONS FROM ANTIPROTONIC ATOMS COMPARED WITH HADRON SCATTERING DATA
Authors: JASTRZȨBSKI J. , TRZCIŃSKA A. , LUBIŃSKI P. , KŁOS B. , HARTMANN F. J. , von EGIDY T. , WYCECH S.
Published: March 2004

The nuclear periphery was studied by using antiprotons. Two experimental methods were applied: analysis of the antiproton annihilation residues one mass unit lighter than the target mass by nuclear spectroscopy and the measurement of strong interaction effects on antiprotonic level widths and shifts. 26 isotopes from a wide range of mass numbers (40<A<238) were investigated. The gathered antiprotonic-atom data were compared with the results obtained using hadron scattering methods and with some expectations from theoretical approaches.
IRREDUCIBLE REPRESENTATIONS OF DOUBLE POINT GROUPS WITHIN THE HARMONIC OSCILLATOR BASIS
Authors: GÓŹDŹ A. , OLSZEWSKI A.
Published: March 2004

It is known, that i.r. of double point groups can be expressed in terms of Wigner functions. Using the projection method proposed by O. Barut and R. Raczka the appropriate basis of i.r. of double point groups within the harmonic oscillator space have been derived. The appropriate numeric and symbolic algebra programs have been constructed.
NEUTRINOLESS DOUBLE BETA DECAY CONSTRAINED BY THE EXISTENCE OF LARGE EXTRA DIMENSIONS
Authors: GÓŹDŹ MAREK , KAMIŃSKI WIESŁAW A.
Published: March 2004

We present the possible influence on the half-life of neutrinoless double beta decay coming from the existence of n extra spatial dimensions. The half-life in question depends on the mass of the electron neutrino. We base our analysis on the Majorana neutrino mass mechanism in Arkani-Hamed–Dimopoulos–Dvali model.
CHARACTERIZATION OF ESSENTIAL GRAPHS BY MEANS OF THE OPERATION OF LEGAL MERGING OF COMPONENTS
Authors: STUDENÝ MILAN
Published: March 2004

One of the most common ways of representing classes of equivalent Bayesian networks is the use of essential graphs which are also known in the literature as completed patterns or completed pdags. The name essential graph was proposed by Andersson, Madigan and Perlman who also gave a graphical characterization of essential graphs. In this paper an alternative characterization of essential graphs is presented. The main observation is that every essential graph is the largest chain graph within a special class of chain graphs. More precisely, every equivalence class of Bayesian networks is contained in an equivalence class of chain graphs without flags (= certain induced subgraphs). A special operation of legal merging of (connectivity) components for a chain graph without flags is introduced. This operation leads to an algorithm for finding the essential graph on the basis of any graph in that equivalence class of chain graphs without flags which contains the equivalence class of a Bayesian network. In particular, the algorithm may start with any Bayesian network.
BAYESIAN NETWORKS IN EDUCATIONAL TESTING
Authors: VOMLEL JIŘÍ
Published: March 2004

In this paper we discuss applications of Bayesian networks to educational testing. Namely, we deal with the diagnosis of person's skills. We show that when modeling dependence between skills we can get better diagnosis faster. We present results of experiments with basic operations that use fractions. The experiments suggest that the test design can benefit from a Bayesian network that models relations between skills, not only in the case of an adaptive test but also when designing a fixed (non-adaptive) test.
RISK ANALYSIS AND SCIENCE
Authors: AVEN TERJE
Published: March 2004

In this paper we discuss the scientific basis of risk analysis, when a Bayesian approach is the foundation of the analysis. We argue that the analysis cannot be judged by reference to the traditional science paradigms alone, such as the natural sciences, social sciences, mathematics and probability theory. There is a need for recognitions of a risk analysis science which is related to the establishment of principles, methods and models to analysis, describe and communicate risk, in a decision-making context. The "goodness" of these principles, methods and models cannot be evaluated by reference to the accuracy in describing the world, as risk analysis is a tool for expressing and communicating uncertainty about the world. Empirical control is only relevant to some degree. An example of a risk analysis of an offshore installation is used to illustrate important issues.
A FUZZY GROUP ASSESSMENT MODEL FOR EVALUATING THE RATE OF AGGREGATIVE RISK IN SOFTWARE DEVELOPMENT
Authors: LEE HUEY-MING , LEE TSUNG-YEN , LEE SHU-YEN , CHEN JAN-JO
Published: March 2004

This paper presents a new method for group decision-making to evaluate the rate of aggregative risk in a fuzzy environment using fuzzy sets theory during any phase of the life cycle. The proposed algorithm is easier and more efficient than the existing methods.
MULTI-STATE RELIABILITY MODELS FOR LIGHTNING HAZARD ASSESSMENT
Authors: SZCZERBIŃSKI MAREK
Published: March 2004

Lightning protection of buildings has been practised for ages but we still lack the model in terms of reliability theory. The paper is a proposition to apply some reliability models in the lightning protection. The building equipped with lightning protection is treated as the 4-state object. The intensities of transition from one state to another have been found on the basis of partial probabilities of inadmissible damages caused by a lightning stroke. The values of these intensities can be calculated on the basis of so called "partial risks" which are determined by entirety of the circumstances referring to the structure (the design, construction, content of the building, lightning protection device design, relief, geographical situation etc.).
ON VARIABLE SAMPLE SIZE $\bar X$ CHART FOR PROCESSES WITH DOUBLE ASSIGNABLE CAUSES
Authors: SIM S. B. , KANG C. W. , XIE M.
Published: March 2004

In statistical process control applications, variable sample size (VSS) [Formula: see text] chart is often used to detect the assignable cause quickly. However, it is usually assumed that only one assignable cause results in the out-of-control in the process. There are papers dealing with double assignable causes for traditional fixed sample size Shewhart chart. In this paper, we consider double assignable causes to occur with compound in the process and adopt the Markov chain approach to investigate the statistical properties of VSS [Formula: see text] chart. A procedure that can compute the optimal sample sizes is proposed.
CLASSIFYING SOFTWARE MODULES INTO THREE RISK GROUPS
Authors: SZABO ROBERT M. , KHOSHGOFTAAR TAGHI M.
Published: March 2004

Building on our earlier work in detecting high risk software modules in object-oriented systems, we extend the two group discriminant classification model to three risk groups. First, we give an overview of the discriminant modeling methodology. Using traditional and object-oriented software product measures collected from a commercial system, we develop two discriminant fault models. One model incorporates only traditional measures while the other model includes both traditional and object-oriented measures. The independent variables of both models are principal components derived from the observed software measures. The models are used to classify the modules comprising the system into three groups: high, medium, and low risk. Quality of fit and classification performance of both models are reported.

We show that for this case study, the addition of the object-oriented measures enhances the model by reducing the overall misclassification rate and significantly reducing the misclassifications in the medium group. Last of all, we tender a cost based method to determine under what condition a three group model is superior to the simpler two group model. Our results suggest that additional case studies are needed to help develop a clearer picture of three group discriminant models and the utility of object-oriented software measures in general.
DATA-DRIVEN COORDINATION IN PEER-TO-PEER INFORMATION SYSTEMS
Authors: BUSI NADIA , MONTRESOR ALBERTO , ZAVATTARO GIANLUIGI
Published: March 2004

Peer-to-peer (P2P) has recently emerged as a promising model for supporting scalable networks composed of autonomous and spontaneously cooperating entities. The key concept in P2P is decentralization: the resources, the services, as well as the control are not in charge of specialized nodes in the network, but each node (called peer in this context) is directly involved in the management of all these aspects. Besides the advantages of decentralization (autonomy, adaptability, collaboration, and dinamicity just to mention few of them) one of the main drawbacks is the impossibility to predict the topology of the network, thus leaving at run-time any decision about the management of the interaction among the peers. For this reason, we consider useful to provide the developers of P2P applications with a high-level coordination language to be exploited to program the coordination among the peers. In this paper, we present [Formula: see text], a new data-driven coordination model suitable for P2P networks, and we describe [Formula: see text], an implementation of the [Formula: see text] coordination model based on the JXTA peer-to-peer technology.
SYNCHRONIZATION ANALYSIS FOR DECENTRALIZING COMPOSITE WEB SERVICES
Authors: NANDA MANGALA GOWRI , KARNIK NEERAN
Published: March 2004

Web Services are emerging as the standard mechanism for making information and software available programmatically via the Internet, and as building blocks for applications. A composite web service may be built using multiple component web services. Once its specification has been developed, the composite service may be orchestrated either using a centralized engine or in a decentralized fashion. Decentralized orchestration brings performance benefits, and improves scalability and concurrency. Dynamic binding coupled with decentralized orchestration adds high availability and fault tolerance to the system. However in such systems, the coordination between components needs to be carefully designed to ensure correct execution of the composite and to limit the synchronization overheads.

In this paper, we categorize different forms of concurrency and provide an algorithm to identify these forms in a composite service specification. We explore different mechanisms for transferring data between the components in the presence of different forms of concurrency. Then we experimentally evaluate the efficiency and scalability of each mechanism. We also analyze the coordination requirements of a decentralized orchestration in the presence of dynamic binding and fault propagation.
NONLINEAR STABILITY ANALYSIS OF THIN-WALLED FRAMES USING UL–ESA FORMULATION
Authors: TURKALJ GORAN , BRNIĆ JOSIP
Published: March 2004

This work presents a one-dimensional finite element formulation for nonlinear analysis of spaced framed structures with thin-walled cross-sections. Within the framework of updated Lagrangian formulation, the nonlinear displacement field of thin-walled cross-sections, which accounts for restrained warping as well as the second-order displacement terms due to large rotations, the equations of equilibrium are firstly derived for a straight beam element. Due to the nonlinear displacement field, the geometric potential of semitangential moment is obtained for both the torsion and bending moments. In such a way, the joint moment equilibrium conditions of adjacent non-collinear elements are ensured. Force recovering is performed according to the external stiffness approach. Material nonlinearity is introduced for an elastic-perfectly plastic material through the plastic hinge formation at finite element ends and for this a corresponding plastic reduction matrix is determined. The interaction of element forces at the hinge and the possibility of elastic unloading are taken into account. The effectiveness of the numerical algorithm discussed is validated through the test problem.
HEXAHEDRAL FOURIER p-ELEMENTS FOR VIBRATION OF PRISMATIC SOLIDS
Authors: LEUNG A. Y. T. , ZHU B.
Published: March 2004

Fourier p-elements of trapezoidal and cubical hexahedron shapes for the free vibration analysis of 3D elastic solids are presented. Trigonometric functions are used as enriching functions to avoid ill-conditioning problems associated with high order polynomials. The element matrices are analytically integrated in closed form. With the additional Fourier degrees-of-freedom, the accuracy of the computed natural frequencies is greatly improved. As an example, the natural frequencies of a cantilever cube are analyzed by a rectangular hexahedron Fourier p-element, two trapezoidal hexahedron Fourier p-elements and the conventional linear finite elements. The results show that the convergence rate of the present elements is very fast with respect to the number of trigonometric terms. The present elements also produce higher accurate modes than the linear finite elements for the same number of degrees-of-freedom. Furthermore, the first six natural frequencies of a cantilever hexagonal prism and a number of concrete dams with different lengths are given as numerical examples.
CLOSED-FORM TRIGONOMETRIC SOLUTIONS FOR INHOMOGENEOUS BEAM-COLUMNS ON ELASTIC FOUNDATION
Authors: CALIÒ IVO , ELISHAKOFF ISAAC
Published: March 2004

In this study, a special class of closed-form solutions for inhomogeneous beam-columns on elastic foundations is investigated. Namely the following problem is considered: find the distribution of the material density and the flexural rigidity of an inhomogeneous beam resting on a variable elastic foundation so that the postulated trigonometric mode shape serves both as vibration and buckling modes. Specifically, for a simply-supported beam on elastic foundation, the harmonically varying vibration mode is postulated and the associated semi-inverse problem is solved that result in the distributions of flexural rigidity that together with a specific law of material density, an axial load distribution and a particular variability of elastic foundation characteristics satisfy the governing eigenvalue problem. The analytical expression for the natural frequencies of the corresponding homogeneous beam-column with a constant characteristic elastic foundation is obtained as a particular case. For comparison the obtained closed-form solution is contrasted with an approximate solution based on an appropriate polynomial shape, serving as trial function in an energy method.
DESIGN OF LATERAL BRACES FOR COLUMNS CONSIDERING CRITICAL IMPERFECTION OF BUCKLING
Authors: TAKAGI J. , OHSAKI M.
Published: March 2004

The present paper discusses the design of column-type structures, which are composed of columns and lateral braces attached perpendicular to the columns. Buckling of the braces of this kind of structures directly leads to global buckling of the columns. The brace-buckling modes are successfully detected by considering higher-order geometrically nonlinear relations and by introducing Green's strain into the total potential energy of the structure. Sensitivity analysis of the eigenvalues of the tangent stiffness matrix under fixed load condition is carried out with respect to imperfections of the nodal locations. Furthermore, the critical imperfection that most drastically reduces the eigenvalues are calculated and buckling loads of the imperfect systems are evaluated. The numerical results show that the second or higher eigenmode of the tangent stiffness matrix of the perfect system should be sometimes used for estimating the buckling load of the imperfect system. Design examples are presented using the proposed method, and they are compared with those in accordance with an allowable-stress design standard. The results show a possibility of reducing the sizes of the brace sections.
HYBRID EVOLUTIONARY AND ANNEALING ALGORITHMS FOR NONLINEAR DISCRETE CONSTRAINED OPTIMIZATION
Authors: WAH BENJAMIN W. , CHEN YIXIN
Published: March 2004

This paper presents a procedural framework that unifies various mechanisms to look for discrete-neighborhood saddle points in solving discrete constrained optimization problems (DCOPs). Our approach is based on the necessary and sufficient condition on local optimality in discrete space, which shows the one-to-one correspondence between the discrete-space constrained local minima of a problem and the saddle points of the corresponding Lagrangian function. To look for such saddle points, we study various mechanisms for performing ascents of the Lagrangian function in the original-variable subspace and descents in the Lagrange-multiplier subspace. Our results show that CSAEA, a combined constrained simulated annealing and evolutionary algorithm, performs well when using mutations and crossovers to generate trial points and accepting them based on the Metropolis probability. We apply iterative deepening to determine the optimal number of generations in CSAEA and show that its performance is robust with respect to changes in population size. To test the performance of the procedures developed, we apply them to solve some continuous and mixed-integer nonlinear programming (NLP) benchmarks and show that they obtain better results than those of existing algorithms.
EVOLUTIONARY ALGORITHMS FOR RESOURCE CONSTRAINED NON-SERIAL MIXED FLOW SHOPS
Authors: BURDETT ROBERT L. , KOZAN ERHAN
Published: March 2004

In this paper the resource-constrained flow shop (RCF) problem is addressed. A number of realistic extensions are incorporated, including non-serial precedence requirements, mixed flow shop situations, and the distribution of the human workforce among a number of pre-determined groups. The RCF is then solved by meta-heuristics, primarily of the evolutionary type. An extensive numerical investigation, including a case study of a particular industrial situation, details the implementation and execution of the heuristics, and the efficiency of the proposed algorithms.
ImmunologicalMemory toViralInfections
Authors: Welsh Raymond M. , Selin Liisa K. , Szomolanyi-Tsuda Eva
Published: March 2004

▪ Abstract  The purpose of immunological memory is to protect the host from reinfection, to control persistent infections, and, through maternal antibody, to protect the host's immunologically immature offspring from primary infections. Immunological memory is an exclusive property of the acquired immune system, where in the presence of CD4 T cell help, T cells and B cells clonally expand and differentiate to provide effector systems that protect the host from pathogens. Here we describe how T and B cell memory is generated in response to virus infections and how these cells respond when the host is infected again by similar or different viruses.
On explicit reciprocity law over formal groups
Authors: Zhang Shaowei
Published: March 2004

Let 𝔣 be a one‐dimensional Lubin‐Tate formal
group over ℤp. Colmez (1998) and Perrin‐Riou (1994) proved an explicit reciprocity
law for tempered distributions over the formal group
𝔾m. In this paper, the general explicit reciprocity
law over the formal group 𝔣 is proved.
Nonexistence results of solutions to systems of semilinear differential inequalities on the Heisenberg group
Authors: El Hamidi Abdallah , Kirane Mokhtar
Published: March 2004

We establish nonexistence results to systems of differential inequalities on the (2N + 1)‐Heisenberg group. The systems considered here are of the type (ESm). These nonexistence results hold for N less than critical exponents which depend on pi and γi, 1 ≤ i ≤ m. Our results improve the known estimates of the critical exponent.
Spectral analysis for differential operators with singularities
Authors: Yurko Vjacheslav Anatoljevich
Published: March 2004

Nonselfadjoint boundary value problems for second‐order differential equations on a finite interval with nonintegrable singularities inside the interval are considered under additional sewing conditions for solutions at the singular point. We study properties of the spectrum, prove the completeness of eigen‐ and associated functions, and investigate the inverse problem of recovering the boundary value problem from its spectral characteristics.
Transcript Expression of Matrix Metalloproteinases in the Conjunctiva following Glaucoma Filtration Surgery in Rabbits
Authors: Liu Catherine Jui-ling , Huang Yu-Lun , Chiu Allen W. , Ju Jyh-Phen
Published: March 2004

Purpose: To determine the changes in the expression of transcripts of matrix metalloproteinases (MMPs) and their tissue inhibitor (TIMP) in the conjunctiva following glaucoma filtration surgery (GFS). Methods: The reverse transcription-polymerase chain reaction method was performed on tissue specimens obtained from adult rabbits undergoing GFS at various postoperative time points. Results: MMP 1 decreased more than 7-fold from its baseline level during the first 2 weeks following surgery. MMP 2 decreased on the 1st postoperative day, but increased on day 2, and remained elevated for 2 weeks. The postoperative level of MMP 14 did not change much from baseline except that noted on day 9. The TIMP 1 expression showed an early biphasic pattern. MMP 3 and MMP 9 were not detected in all the specimens. Conclusions: The transcript expression of MMPs and TIMP 1 in the conjunctiva is altered following GFS, with each gene product demonstrating a unique temporal pattern.
Hyperglycaemic index as a tool to assess glucose control: a retrospective study
Authors: Vogelzang Mathijs , van der Horst Iwan CC , Nijsten Maarten WN
Published: March 2004

Introduction

Critically ill patients may benefit from strict glucose control. An objective measure of hyperglycaemia for assessing glucose control in acutely ill patients should reflect the magnitude and duration of hyperglycaemia, should be independent of the number of measurements, and should not be falsely lowered by hypoglycaemic values. The time average of glucose values above the normal range meets these requirements.

Methods

A retrospective, single-centre study was performed at a 12-bed surgical intensive care unit. From 1990 through 2001 all patients over 15 years, staying at least 4 days, were included. Admission type, sex, age, Acute Physiology and Chronic Health Evaluation II score and outcome were recorded. The hyperglycaemic index (HGI) was defined as the area under the curve above the upper limit of normal (glucose level 6.0 mmol/l) divided by the total length of stay. HGI, admission glucose, mean morning glucose, mean glucose and maximal glucose were calculated for each patient. The relations between these measures and 30-day mortality were determined.

Results

In 1779 patients with a median stay in the intensive care unit of 10 days, the 30-day mortality was 17%. A total of 65,528 glucose values were analyzed. Median HGI was 0.9 mmol/l (interquartile range 0.3–2.1 mmol/l) in survivors versus 1.8 mmol/l (interquartile range 0.7–3.4 mmol/l) in nonsurvivors (P < 0.001). The area under the receiver operator characteristic curve was 0.64 for HGI, as compared with 0.61 and 0.62 for mean morning glucose and mean glucose. HGI was the only significant glucose measure in binary logistic regression.

Conclusion

HGI exhibited a better relation with outcome than other glucose indices. HGI is a useful measure of glucose control in critically ill patients.
Parallel and overlapping HIV and bloodborne hepatitis epidemics in Africa
Authors: Gisselquist David , Perrin Luc , Minkin Stephen F
Published: March 2004

A world overview of HIV and hepatitis B and C virus (HBV and HCV) infections shows strong parallels in the distribution of generalized epidemics. However, several recent papers have argued that HCV prevalence in countries and cohorts in sub-Saharan Africa is too low to allow parenteral transmission to account for an important proportion of HIV infections. This conclusion is unwarranted. The transmission efficiencies of HCV and HIV through needlestick accidents are similar, while some parenteral exposures - such as intramuscular injections - may be more efficient in transmitting HIV than HCV. Much of the data used to show current low HCV prevalence in Africa comes from blood samples collected in 1986-95. For South Africa, the picture of low and stable HCV prevalence in the 1990s is based on selected evidence and ignores multiple studies reporting 3-5.4% prevalence in the black population. From a literature search, we found 62 cohorts in Africa with information on HCV and HIV prevalence. Across these cohorts, there is a trend for HCV prevalence to increase with HIV, though much of the variance is unexplained. For 25 cohorts with sufficient data, the median relative risk for HCV infection for persons with HIV is 1.52.
Predictors of maternal HIV infection at the primary care level in inner city Ibadan
Authors: Lawoyin T O , Adewole D A
Published: March 2004

National HIV prevalence rate is derived from the sentinel surveys, which are carried out once in two years and remain anonymized. Epidemiological data are largely unavailable on the pregnant HIV-positive mothers particularly at the grass root level. This information is urgently needed when developing a realistic intervention programme.

Three hundred and forty-three consenting pregnant women attending a randomly selected primary health care clinic in inner city Ibadan from April to November 2001 were enrolled at booking and followed up till delivery of their babies. Sociodemographic and reproductive health data were collected by questionnaire and all mothers were screened for HIV/AIDS using an enzyme-linked immunosorbent assay based rapid test.

Results showed that about one in three teenage mothers screened positive, having the highest HIV rate. HIV prevalence rate reduced, though not significantly, in mothers 20-29 years and those 30-39 years with mothers in these groups having similar rates. No mother over 39 years screened positive. Following logistic regression analysis, young age 15-19 years, was associated with a significantly increased risk for infection at the primary health care level ( P =0.046). Christian religion was associated with a lower risk ( P =0.038), and mothers who booked late in pregnancy ( P =0.025) or had husbands in the lower socio-economic class ( P =0.001) were less likely to be infected. None of the women were aware of their HIV status prior to the study.

With a predominantly heterosexual mode of HIV transmission, it is necessary to identify infected pregnant women early through voluntary counselling and testing (VCT), so that they can be given the option to take preventive drugs, which would among other benefits reduce mother-to-child transmission, and help infected mothers stay healthy and productive for longer.