Determinants of Enterprise System Adoption Across the System Lifecycle: Exploring the Role of Economic Development

The authors studied enterprise systems adoption in transition and less-developed economies within the European Union in search of determinants (critical success factors and barriers) across the system lifecycle. They found 14 determinants drawing from interviews with practitioners whose experience exceeds 280 projects. The authors compared their data with prior results from well-developed countries and concluded that determinants and their criticality across the lifecycle depend on the level of economic development. The authors discussed implications and provided recommendations.     

Characterisation and engineering properties of tectonically undisturbed but lithologically varied sedimentary rock masses

Tectonically undisturbed sedimentary rocks deposited in a quiescent shallow marine environment often include a sequence of strata that may present significant lithological variety at the scale of an engineering structure. Such rock masses exhibit engineering properties that are significantly different from tectonically disturbed rock masses of similar composition. For example, molasse consists of a series of tectonically undisturbed sediments of sandstones, conglomerates, siltstones and marls, produced by the erosion of mountain ranges after the final phase of an orogeny. They behave quite differently from flysch which has the same composition but which was tectonically disturbed during the orogeny. The molasses behave as continuous rock masses when they are confined at depth and the bedding planes do not appear as clearly defined discontinuity surfaces. Close to the surface the layering of the formations is discernible and only then similarities may exist with the structure of some types of flysch. Therefore extreme care is necessary in the use of geotechnical classification systems for the selection of design parameters, in order to avoid penalizing the rock mass unnecessarily. A discussion on the use of the geological strength index (GSI) for the characterisation of such rock masses is presented. Two GSI charts are proposed for estimating the mechanical properties of these masses: one mainly for tunnels; and the second for surface excavations. An example is given to illustrate the process of tunnel design in molassic rocks.     

Controlling the miscibility of polyethylene/layered silicate nanocomposites by altering the polymer/surface interactions

Polyethylene/layered silicate nanocomposites are synthesized utilizing three types of polymeric surfactants/compatibilizers in order to influence the miscibility of polyethylene with the nanoparticle surface. The additives are designed so that they can play the role of a polymeric surfactant modifying the hydrophilic clay or of a compatibilizer with the organoclay. Model additives, especially synthesized for this study, included: polyethylene chains, which possess either a single functional end-group or multiple functional groups along the chain, as well as functional diblock copolymers. Maleic anhydrite grafted polyethylene with a low degree of functionalization was used as well. The structure of the resulting micro- or nanocomposites was investigated by X-ray diffraction and transmission electron microscopy. Immiscible hybrids as well as intercalated and/or exfoliated nanocomposites are obtained in a controlled way, depending on the kind of additive and its concentration in the mixture. The most important factor controlling the structure and the properties is the ratio of additive to nanoparticles. The rheological properties of the hybrids correlate well with the final micro- or nanostructure.     

Assessment of retrofitting measures and solar systems' potential in urban areas using Geographical Information Systems: Application to a Mediterranean city

Energy efficient management of urban environment is undoubtedly a challenging task. Although the topography of cities and their urban built environment are considered as the main layers for environmental analysis, further geographical data has to be taken into account as well. In particular, economic and social data should also be considered on spatial level, as they highly affect the need for energy conservation measures. Furthermore, land and building uses, urban mobility and transactions are also crucial factors that influence energy use and management. Within this framework, this paper examines the establishment of a methodology approach in order to estimate energy conservation and solar systems potential in urban environments, based on the implementation of geoinformatics decision-making tools into a fine-scale analysis over an extended geographical area. All above multi-criteria variables can be efficiently analyzed by applying Geographical Information System (GIS) tools, which are particularly applied for the establishment of the proposed methodology. The scope of the paper is to deliver an integrated assessment tool, in order to aid researches as well as public bodies for the implementation of energy policies concerning the urban built environment. A case study of the urban area of Thessaloniki in Northern Greece is presented focusing on the evaluation of current energy performance and possible retrofit measures for the existing urban building stock, especially for typical residential multi-family (MF) buildings. Conclusively, the general outcome obtained by current research, indicate that denser urban areas perform limited potential both for retrofitting interventions on buildings' envelope and solar systems applications, apart from the quality and the age of building constructions.     

From “Onto-GeoNoesis” to “Onto-Genesis”: The Design of Geographic Ontologies

An important issue in geographic ontological research is the ability to design new ontologies. In this context, we first explore the desiderata of domain ontologies in terms of their constituting elements: i.e., the lexicon, concepts, relations, and axioms. Furthermore, we touch upon several characteristics of geographic concepts, which have puzzled geographic information scientists, and present critical topics of geographic ontological research. Based on the previous aspects of the problem, and guided by prior work of analyzing existent geographic ontologies, we have identified their qualities and deficiencies with regard to completeness and adequacy. This meta-ontological approach has guided us in presenting herein, a framework for generating robust geographic ontologies, which will comply with the semantics of the concepts of the specific domain.     

Comparative Fractional Efficiency Predictions by Selected Cyclone Simulation Models

The recently introduced ambient air quality standards for fine particulates expand the use of available control system simulation models, from the prediction of total particulate matter removal efficiencies, to the prediction of PM2.5 and PM10 (particulate matter with diameters less than 2.5 and 10?μm) ones. In order to assess the suitability of cyclone simulation models for this task, the fractional efficiency predictions of six prominent models (Lapple, Leith and Licht, Dietz, Mothes and Loffler, Iozia and Leith, and Mothes and Loffler with the turbulent dispersion coefficient of Salcedo and Coelho) are compared for a number of “standard” cyclone design configurations under a wide range of cyclone diameters and pressure drops. The results reveal a significant discrepancy among model predictions, suggesting that at least some of the models considered are unsuitable for predicting size-specific (e.g., PM2.5 and PM10) cyclone efficiencies. They also show that the sensitivity of fractional efficiencies to changes in the configuration ratios, diameter, and gas pressure drop varies widely, and in some cases even in opposite directions, among models. The above-noted results demonstrate the need for a systematic model validation against credible and sufficiently extensive experimental data sets.     

Dynamic–static unsupervised sequentiality,statistical subunits and lexicon for sign language recognition

We introduce a new computational phonetic modeling framework for sign language (SL) recognition. This is based on dynamic–static statistical subunits and provides sequentiality in an unsupervised manner, without prior linguistic information. Subunit “sequentiality” refers to the decomposition of signs into two types of parts, varying and non-varying, that are sequentially stacked across time. Our approach is inspired by the Movement–Hold SL linguistic model that refers to such sequences. First, we segment signs into intra-sign primitives, and classify each segment as dynamic or static, i.e., movements and non-movements. These segments are then clustered appropriately to construct a set of dynamic and static subunits. The dynamic/static discrimination allows us employing different visual features for clustering the dynamic or static segments. Sequences of the generated subunits are used as sign pronunciations in a data-driven lexicon. Based on this lexicon and the corresponding segmentation, each subunit is statistically represented and trained on multimodal sign data as a hidden Markov model. In the proposed approach, dynamic/static sequentiality is incorporated in an unsupervised manner. Further, handshape information is integrated in a parallel hidden Markov modeling scheme. The novel sign language modeling scheme is evaluated in recognition experiments on data from three corpora and two sign languages: Boston University American SL which is employed pre-segmented at the sign-level, Greek SL Lemmas, and American SL Large Vocabulary Dictionary, including both signer dependent and unseen signers' testing. Results show consistent improvements when compared with other approaches, demonstrating the importance of dynamic/static structure in sub-sign phonetic modeling.     

Removal of Pb(II) from aqueous solutions by using clinoptilolite and bentonite as adsorbents

In the present study, the ability of natural zeolite clinoptilolite and bentonite (clay) to remove Pb(II) from aqueous solutions has been investigated in batch reactors with a maximum contact time of 120 min. Adsorption tests of Pb(II) were carried out using a solution concentration of 1,036 ppm at initial pH = 4, and solid to liquid ratio of 2 g/100 mL. The effects of agitation speed (0, 100, 200, 500 rpm), temperature (28°C, 45°C, 60°C) and particle size (2.5–5.0 mm, dust) of the minerals were examined. The effect of acidity of the aqueous solution was also examined. Bentonite was found to be more effective for the removal of Pb(II) than clinoptilolite, under the experimental conditions used. The removal of Pb(II) using bentonite reached 100% at ambient temperature and mild agitation (100 rpm), while it was approximately 90% at 60°C without agitation. On the other hand, the highest removal level reached by clinoptilolite was 55%. Clinoptilolite dust is found to be more efficient than granular clinoptilolite. Agitation and temperature affected the uptake of Pb(II), especially in the case of granular clinoptilolite (2.5–5.0 mm). Finally, it can be seen that acidity of the aqueous solution influences the removal of lead by the minerals. The adsorption of lead increases with an increase in pH of the solution from 1 to 4.