A hybrid method for inversion of 3D DC resistivity logging measurements

This paper focuses on the application of hp hierarchic genetic strategy (hp–HGS) for solution of a challenging problem, the inversion of 3D direct current (DC) resistivity logging measurements. The problem under consideration has been formulated as the global optimization one, for which the objective function (misfit between computed and reference data) exhibits multiple minima. In this paper, we consider the extension of the hp–HGS strategy, namely we couple the hp–HGS algorithm with a gradient based optimization method for a local search. Forward simulations are performed with a self-adaptive hp finite element method, hp–FEM. The computational cost of misfit evaluation by hp–FEM depends strongly on the assumed accuracy. This accuracy is adapted to the tree of populations generated by the hp–HGS algorithm, which makes the global phase significantly cheaper. Moreover, tree structure of demes as well as branch reduction and conditional sprouting mechanism reduces the number of expensive local searches up to the number of minima to be recognized. The common (direct and inverse) accuracy control, crucial for the hp–HGS efficiency, has been motivated by precise mathematical considerations. Numerical results demonstrate the suitability of the proposed method for the inversion of 3D DC resistivity logging measurements.     

Exploring Root Problems in Enterprise System Adoption From an Employee Age Perspective: A People-Process-Technology Framework

ABSTRACT

This study investigates the role of employees’ age in the perception of problems during enterprise systems (ES) adoption and use. The analysis of data gathered from Polish ES practitioners suggests that ability to perceive the broad impact of technology decreases with age. The findings also illustrate that younger employees recognize root problems among technical issues, while older practitioners focus on impediments associated with people and emphasize the role of competence and training as root causes.     

Factors Influencing The Success Of E-Government

This research focuses on the critical success factors (CSFs) of e-government. Its main purposes are to (1) explain the development of the methodology of CSFs for e-government, (2) present the practical implementation of this methodology in Polish public administration, and (3) to assess the preliminary results of the practical implementation. The article continues as follows. First, the article clarifies the concept of e-government and the CSFs for e-government. Second, the methodology of CSFs for e-government is explained in detail. Third, the article presents the preliminary results of the practical implementation of this methodology in Poland, at the local and state level of government. The article concludes with a discussion on research findings, implications, and avenues for further research. This work contributes to extant research by showing a holistic approach to the CSFs for e-government.     

A necessary condition of viability for fractional differential equations with initialization

In this paper, viability results for nonlinear fractional differential equations with the Riemann-Liouville derivative are proved. We give a necessary condition for fractional viability of a locally closed set with respect to a nonlinear function.     

Segmentation of regions of interest and post-segmentation edge location improvement in computer-aided bone age assessment

Segmentation of anatomical structures in radiological images is one of the important steps in the computerized approach to the bone age assessment. In this paper a method dealing with correct location of the borders in the epi-metaphyseal regions of interest is described. The well segmented bone structures are obtained utilizing the Gibbs random fields as the first segmentation step; however this method does not prove to be adequate in the correct outline of other tissues in the epi-metaphyseal area. In order to correct delineation of cartilage in this region, the second segmentation step utilizing the active contours serving as a post-segmentation edge location technique is applied. Controlling of tension and bending of the active contour requires a set of weights in the energy functional to be set. To adjust the weights and to initially test the methodology a model of region of interest containing three different anatomical structures corrupted with Gaussian noise has been designed. Combined methodology of Gibbs random fields and active contours with the final set of weights was applied to 200 regions of interest randomly selected from 1100 left hand radiographs. A meaningful improvement in terms of ultimate contour location and smoothing has been observed in regions with cartilage or bone convexity developed near the bottom region of the epiphysis.

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Biosurfactant production by <Emphasis Type="Italic">Bacillus coagulans</Emphasis>

A new biosurfactant producer, Bacillus coagulans, was isolated from soil. Its 24-h-old culture broth had a low surface tension (27–29 mN/m). Optimization of cell growth of this bacterium led to maximal biosurfactant production with glucose or starch as the organic carbon source, a pH in the range 4.0–7.5, and incubation temperatures from 20 to 45°C. The crude biosurfactants obtained after neutralization and lyophilization of the acid precipitate yielded a minimal aqueous solution surface tension value of 29 mN/m and an interfacial tension value of 4.5 mN/m against hexadecane. The critical micelle concentration of the crude biosurfactants was 17 mg/L. Addition of NaCl to the aqueous solution of the crude product caused lowering of surface tension at both the aqueous solution-air and aqueous solution-n-hexadecane interfaces. These results indicate that the biosurfactants obtained have potential environmental and industrial applications and may have uses in microbially enhanced oil recovery.     

Synthesis of 1-propenyl ethers and their using as modifiers of UV-cured coatings in radical and cationic polymerization

The 1-propenyl ethers of diols and polyols have recently attracted increasing attention as monomers and comonomers because these compounds undergo UV-photoinitiated polymerization. The synthesis of 1-propenyl ethers via the isomerization of corresponding, readily available allyl ethers catalysed by homogenized transition metal complexes with recycling of catalyst has been described. The properties of UV-cured coatings have been investigated for various compositions containing: the model ether (i.e. 1,4-di(1-propenyloxy)-butane), the unsaturated polyester resin [Estromal 103] or epoxy resin [Epidian 6] and radical (i.e. Irgacure 184) or cationic (i.e. triarylsulfonium salts with metal halide anions: PF₆⁻, SbF₆⁻) initiators. The purified or unrefined (i.e. including 0.05 mol% homogenized ruthenium(II) complex [RuClH(CO)(PPh₃)₃]) 1,4-di(1-propenyloxy)butane were applied as modifiers. The effect of presence of homogenized [RuClH(CO)(PPh₃)₃] in the composition has been discussed.     

Effect of restricted geometry and external pressure on the phase transitions in ammonium hydrogen sulfate confined in a nanoporous glass matrix

A study of heat capacity, thermal dilatation, susceptibility to hydrostatic pressure, permittivity and polarization loops was carried out on NH₄HSO₄–porous glass nanocomposites (AHS?+?PG) as well as empty glass matrices. The formation of dendrite clusters of AHS with a size, d_cryst, exceeding the pore size was found. An insignificant anisotropy of thermal expansion of AHS?+?PG showing statistically uniform distribution of AHS with random orientations of nanocrystallites over the matrix was observed. The effect of internal and external pressures on thermal properties and permittivity was studied. At the phase transition P-1???Pc, a strongly nonlinear decrease in the entropy ΔS₂ and volume strain (ΔV/V)_T2 was observed with decreasing d_cryst. The linear change in temperatures of both phase transitions P-1???Pc???P2₁/c under hydrostatic pressure is accompanied by the expansion of the temperature range of existence of the ferroelectric phase Pc, while this interval narrows as d_cryst decreases.     

Experimental Evaluation of Agent-based Approaches to Solving Multi-mode Resource-Constrained Project Scheduling Problem

ABSTRACT

In this paper, a rank-based nonparametric statistical test for measuring the effect of cooperation between optimization agents solving the multi-mode resource-constrained project scheduling problem is presented. To solve this NP-hard optimization problem, different methods are applied including population- and agent-based approaches. One of them is a team of asynchronous agents composed of multiple optimization agents, management agents, and common memories, which through interactions produce solutions of hard optimization problems. Optimization agents represent different methods including local search, path relinking, or tabu search. Interactions are managed through various cooperation strategies based on applying heuristics, reinforcement learning, or population learning.     

Multi-agent system to support decision-making process in design for recycling

In this paper, the application of multi-agent system to support decision-making process in design for recycling is presented. The design for recycling term is highlighted either as the design problem or from the point of view of regulations. The structure of agent system supporting the designer during the design process is showed. The basis of special kind of product model, that is the extension of standard 3D product model, called recycling-oriented product model, is described. The example results of analysis, based on real household appliance model, are presented.