131,017 research outputs found
On Tychonoff-type Hypertopologies.
No full textIn 1975, M. M. Choban \cite{C} introduced a new topology on the set
of all closed subsets of a topological space, similar to the Tychonoff topology but weaker than it. In 1998, G. Dimov and D. Vakarelov \cite{DV} used a generalized version of this new topology, calling it Tychonoff-type topology. The present paper is devoted to a detailed study of Tychonoff-type topologies on an arbitrary family \MM of subsets of a set . When \MM contains all singletons, a description of all Tychonoff-type topologies \OO on \MM is given. The continuous maps of a special form between spaces of the type (\MM,\OO) are described in an isomorphism theorem. The problem of {\em commutability between hyperspaces and subspaces with respect to a Tychonoff-type topology} is investigated as well. Some topological properties of the hyperspaces (\MM,\OO) with Tychonoff-type topologies \OO are briefly discussed
Do Experience and Degree of Innovation Influence Intentionality to Create New Value?
No full textThis paper seeks to study the influence of the moderating role of experience and innovation on the
intentionality to create new value (NVCI). Using a survey data from 157 prospective entrepreneurs, we compare the
perception of experienced and novice entrepreneurs at the pre-founding stage of their venture. We find that experience,
alone, does not moderate the relationship between opportunity confidence and NVCI. However, if entrepreneurs have
required opportunity confidence, then medium and high-level innovation can increase the likelihood of acting on the
opportunity for novice and experienced entrepreneurs respectively. For novice entrepreneurs, the innovation variance
from low to medium moderates the relationship between opportunity confidence and intent. In fact, this relationship
is strengthened by the medium novelty level. As such, novice entrepreneurs may be less willing to market a new
product with a low novelty degree. Whereas, for experienced entrepreneurs, the variance from medium to high,
moderates the relationship
Degree of innovation and the entrepreneurs' intention to create value: A comparison study between experienced and novice entrepreneurs
No full textA vital aspect of entrepreneurial action is the translation of an entrepreneur’s opportunity idea into the creation of new value. This paper examines the moderating roles of the founder’s experience and innovation degree on the relationship between opportunity confidence and new value creation intention (NVCI) at the pre-founding stage of a business. It uses survey data on 77 novice and 80 experienced entrepreneurs from Iran. The results of SEM analysis show that the relationship between opportunity confidence and NVCI is sensitive to the associated degree of innovation: for novice entrepreneurs, the difference is between low and medium degree, while for their experienced counterparts the difference is between medium and high degree
Frames and Grids
No full textM. Barr and M.C. Pedicchio (4) introduced the category Grids of grids in order to show the opposite of the category Top of topological spaces is a quasivariety. J. Adamek and M.c. Pedicchio proved in (2) that there exist a duality D between the category TopSys of topological systems (defined by S.Vickers (11) and the category Grids. In both papers (4) and (2) a description of the full subcategory D(Top) of the category Grids is given. In this paper we describe internally all grids isomorphic to the objects of the full coreflective subcategory D(Loc) of the category Grids, i.e. we characterize internally all grids of the form D(C), where C is a localis topological system (here Loc is the category of locales regarded as a full subcategory of TopSys (see 11). Since, obviously, the category Frm of frames is equivalent to D(Loc), we can say that in this paper those grids which could be called frames are characterized internally. An internal chacterization of all grids which correspond (in the above sense) to the frames having T1 spectra and a generalization of the well-known facty that the spectrum of a locale is a sober space are obtained as well
Structural Blocks Retrieval in Macromolecules: Saliency and Precision Aspects
No full textA structural motif is a compact 3D block of a few secondary structural elements (SSs) - each one with an average of approximately 5 and 10 residues for sheets and helices respectively - which appears in a variety of macromolecules.
Several motifs pack together and form compact, semi-independent units called domains. The domain size varies from about 25 up to 500 amino acids, with an average of approximately 100 residues. This hierarchical makeup of molecules results from the generation of new sequences from preexisting ones, in fact motifs and domains are the common material used by nature to generate new functionalities. Structural biology is concerned with the study of the structure of biological macromolecules like proteins and nucleic acids, and it is expected
to give more insights in the function of the protein than its amino acid sequence. In this paper we propose and analyze a possible performance of a new approach for the detection of structural blocks in large datasets such as the
Protein Data Base (PDB)
Cognitive support for older people from multimedia options
No full textIf older users of multimedia displays could select among presentation options, would they choose display combinations that supported their performance? After three short touch-screen tasks which measured the perceptual and cognitive abilities of 50 older adults, they answered questions about a route on an online map that could be accompanied by written and/or spoken text. Half the participants saw animated routes; and they were less accurate answering questions than those who saw static routes but this did not affect people’s multimedia choices which, although diverse, were systematic. Spoken text was more often selected by people who had lower scores on the spatial working memory task, than by the older adults with higher scores. This suggests that older people with cognitive limitations recognise ways in which multimedia information can be supportive
Thin-wall injection molding of polypropylene using molds with different laser-induced periodic surface structures
No full textIn injection molding, high pressure is required to completely replicate the mold geometry, due to the viscosity of thermoplastic polymers, the reduced thickness of the cavity, and the low mold temperature. The reduction of the drag required to fill a thin-wall injection molding cavity can be promoted by inducing the strong slip of the polymer melt over the mold surface, which occurs within the first monolayer of macromolecules adsorbed at the wall. In this work, the effects of different laser-induced periodic surface structures (LIPSS) topographies on the reduction of the melt flow resistance of polypropylene were characterized. Ultrafast laser processing of the mold surface was used to manufacture nano-scale ripples with different orientation and morphology. Moreover, the effects of those injection molding parameters that mostly affect the interaction between the mold surface and the molten polymer were evaluated. The effect of LIPSS on the slip of the polymer melt was modeled to understand the effect of the different treatments on the pressure required to fill the thin-wall cavity. The results show that LIPPS can be used to treat injection mold surfaces to promote the onset of wall slip, thus reducing the injection pressure up to 13%. POLYM. ENG. SCI., 59:1889–1896, 2019. © 2019 Society of Plastics Engineers
Solving The Bridge Maintenance Problem In Bulgaria - an Analysis of The Opportunities Offered By Composite Materials
No full textMany bridges all around the world experience very hard climatic conditions, and due to the irregular maintenance effort, show different problems of cracking, concrete cover detachment and steel reinforcement wear and corrosion.
In general, as a consequence of the polluted rain wetting, the problem is more evident in vertical structures than in the horizontal ones, and serious problems can arise when the piers and columns are very tall.
In recent times, the solutions offered by composite materials have shown their effectiveness in the field of bridge maintenance. As a consequence of lightness and ease of installation they are particularly intended to the rehabilitation of tall slender structures. Furthermore, the externally bonded reinforcement offers a valid protection to chloride diffusion and rusting of steel rebars.
In the paper the situation of the Bulgarian highways is briefly discussed in order to point out the key factors that promote the deterioration of the concrete structures.
Afterwards, the recent knowledge gained in the retrofit of building and bridges gained in Italy in ten years of external application of FRP as a solving problem tool is summarized.
Finally, the potentiality of these techniques in the solution of the maintenance problem of Bulgarian bridges is reviewed, with the aim to point out the possible cost reduction and life extension characteristic of these solutions, when translated in the Bulgarian environment.
Some application proposals close the presentation
A resource-based view on organic and acquired growth
No full textUnderstanding the sources of business growth is central to both the fields of entrepreneurship and strategy. This is a logical endeavor given the positive macro-level outcomes of firm growth, such as the creation of new jobs, an increase in tax revenues, the provision of innovations, and overall economic growth (Wennekers & Thurik, 1999; Davidsson, 2005). At the same time as the macro-level outcomes, business growth has determinants on the micro-level. Indeed, the majority of firm growth studies have examined a long list of internal factors as predictors of growth, such as the founding team, founder’s prior knowledge and education, access to capital and financing, and/or networks. In particular, these studies argue that the firms’ resources are likely to influence its growth, and its increased size will have implications for what kind of management skills become crucial (e.g. Chandler & Hanks, 1994; Flamholtz, 1986).\ud
Despite the increase in the amount of research into this topic over the past decade (cf. Wiklund, 1998; Delmar, Davidsson & Gartner, 2003) the outcome of these reviews is, however, rather disappointing. It appears that despite the increased research efforts, relatively little of solid, generalizable knowledge has emerged. It has been suggested elsewhere that part of the explanation for this is likely that much research has overly simplistically treated business growth as one phenomenon (cf. Davidsson & Wiklund, 2000). In reality, there are several different modes and patterns of growth. For instance, Delmar, Davidsson and Gartner (2003), using numerous measures of growth, found seven different types of growth patterns. These different modes and patterns require different explanations, and they have different implications on the societal and organization level. \ud
In this book chapter we will focus on one particular aspect of the multi-facetted nature of business growth, namely the distinction between organic (or internal) growth and acquisition growth. While there are exceptions (Niosi, 2003; Delmar, Davidsson, & Gartner, 2003), few empirical studies of firm growth have dealt with this important distinction. More precisely, we will start from an empirical observation concerning organic vs. acquired growth. The observation is that there is a very strong empirical relationship between the size of a growing firm on the one hand, and what proportion of growth is acquired on the other. It turns out that in the smaller firms almost all the growth is organic while the converse is true for growth firms in the largest size classes. The purpose of this book chapter is, firstly, to try to make theoretical sense, within the framework of the resource-based view of the firm (RBV), of the strong firm size acquired share of growth relationship. Secondly, we will test hypotheses based on our theoretical reasoning on two independent sets of data
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