X-ray radiography and tomography for monitoring the penetration depth of consolidants in Opuka – the building stone of Prague monuments

Stone consolidation is one of the major restoration treatments used for historical monuments preservation. A natural stone is a complicated heterogeneous porous system making the process of consolidation dependent on many variables. In practical restoration aims, for a given stone type, the selection of a suitable consolidant and consolidation conditions therefore remains a complex issue. The impregnation depth is a key factor for the assessment of the treatment efficiency. The combination of state-of-the-art hybrid pixel semiconductor detectors with newly available micro-focus X-ray sources makes possible to apply X-ray radiography, an ideal non-destructive tool, for penetration depth monitoring. In this study, high-resolution X-ray radiography is used for monitoring the penetration depth of organosilicon consolidants in the Opuka stone. The penetration depth has been evaluated in relation to the time of consolidation, stone porosity and consolidation mixtures properties. The exact influence of the X-ray contrast agent on the consolidation depth has been investigated as well. The information obtained provides supplementary knowledge on the suitability of investigated products for the treatment of this type of stone. In our study, the capabilities of X-ray radiography have been demonstrated on X-ray radiography simple projections, high-resolution computed tomography (CT) as well as on the dynamic processes monitoring. The results thus can serve also as an instrumental and methodological example applicable for consolidation monitoring of other stone types.     

'NO OPINION'-FILTERS: A COGNITIVE PERSPECTIVE

Research on the use of ‘no opinion’-filters suggeststhat respondents are the less likely to offer a substantiveresponse the more strongly the filter question is worded. Aseries of experiments is reported that demonstrates that filterquestions influence respondents' perception of their task: themore strongly the filter question is worded, the more respondentsassume that they will have to answer difficult questions, andthat they may not have the required knowledge. Accordingly,filter questions discourage respondents from offering globalopinions that they may hold. In line with this assumption, allrespondents who reported not having an opinion in response toa filter question, subsequently provided substantive responseson a global opinion question—presumably because the globalquestion asked was less demanding than expected on the basisof the filter. Analyses of these substantive responses indicatedthat respondents who initially reported not having an opiniondiffered from respondents who reported having one. Methodologicalimplications of these findings for the use of filter questionsand for research on the nature of ‘floating’ arediscussed.     

Konfigurierungskonzepte für DB-basierte technische Entwurfsanwendungen

Zusammenfassung  . Schwerpunkte einer Datenbank-Unterstützung von technischen Entwurfsanwendungen sind eine geeignete Ablaufkontrolle sowie ein geeignetes Datenmodell. Letzteres mu? Versionen komplexer Objekte verwalten k?nnen. Um aus der Gesamtmenge der in einer Datenbank enthaltenen Versionen konsistente Einheiten (Mengen ‚kompatibler’ Versionen) hervorheben zu k?nnen, werden geeignete Konfigurierungskonzepte ben?tigt. Dieses Papier gibt eine Klassifikation verschiedener DB-bezogener Konfigurierungsans?tze, bewertet diese und begründet damit die Wahl, die im Rahmen des Objekt- und Versionsdatenmodells OVM hinsichtlich des zu unterstützenden Konfigurierungskonzeptes getroffen wurde. Wir werden argumentieren, da? insbesondere die Flexibilit?t, die das gew?hlte Konzept sowohl hinsichtlich der Definition von Konfigurationstypen als auch hinsichtlich des Anlegens von Konfigurationen bietet, zu einer besseren Unterstützung von technischen Entwurfsanwendungen als in bestehenden objekt-orientierten Systemen führt. Eingegangen am 14. Oktober 1996/Angenommen am 27. Oktober 1997     

Market orientation in managing relationships with multiple constituencies of Croatian higher education

In this paper, market orientation in Croatian higher education (HE) is discussed within the context of stakeholder-oriented management. Drawing on existing studies, the ‘classical’ empirical model, describing the market orientation of generic nonprofit organisations, has been adapted to the contingencies of the Croatian HE sector. Empirical testing of the model, based on primary data drawn from the majority of public institutions of higher learning in the country, reveals inadequate market orientation toward the relevant stakeholders. Although social market orientation currently does not exist in Croatian HE institutions, the empirical results confirm that it might be possible to initiate a ‘virtuous circle’, in which relevant market orientation and stakeholder management practices, directed toward one or other of the stakeholders, simultaneously enhance orientation toward the other stakeholders. Unfortunately, the current situation in HE is not satisfactory, which could hinder the implementation of development of knowledge society in Croatia.

Distributed delay input shaper design by optimizing smooth kernel functions

The aim of this paper is the development of a general class of input shapers with distributed time delay which leads to retarded spectral properties. The design of the shaper is formulated as a multi-objective optimization problem, where response time and robustness, expressed in terms of residual vibrations, are the main objectives. As a part of the optimization formulation, common requirements for input shapers such as non-decreasing step response and unity steady state gain are considered in the design. Moreover, additional optional requirements, such as smoothness of a step response, jerk and even jounce limits can be added to optimization procedure. The resulting problem can be solved using convex optimization techniques. Several illustrative examples are presented in comparison with classical input shaping techniques. Finally, implementation aspects are discussed. The paper is accompanied by an implementation in MATLAB, including a user-friendly interface for the interactive shaper design.     

A probability ranking principle for interactive information retrieval

The classical Probability Ranking Principle (PRP) forms the theoretical basis for probabilistic Information Retrieval (IR) models, which are dominating IR theory since about 20 years. However, the assumptions underlying the PRP often do not hold, and its view is too narrow for interactive information retrieval (IIR). In this article, a new theoretical framework for interactive retrieval is proposed: The basic idea is that during IIR, a user moves between situations. In each situation, the system presents to the user a list of choices, about which s/he has to decide, and the first positive decision moves the user to a new situation. Each choice is associated with a number of cost and probability parameters. Based on these parameters, an optimum ordering of the choices can the derived—the PRP for IIR. The relationship of this rule to the classical PRP is described, and issues of further research are pointed out.

Integrating alternative learning and assessment in a course of English for law students

Alternative approaches to learning and assessment have become common practice in higher education today. While these approaches have several learning, instructional and assessment advantages for students and teachers, a need exists for a better understanding of their consequential evidence. The purpose of this study was to examine students’ perceptions of, and satisfaction with, the experience of learning English for Law in the environment of a comprehensive learning and assessment system integrating the project component and academic writing portfolio component into the framework of traditional learning. A sample of 58 law majors from Mykolas Romeris University in Vilnius, Lithuania participated in the study. The main findings of the study indicate that the integrated approach to learning English for Law was very well accepted by the students due to the following benefits it presented: (i) this approach is effective and useful in promoting students’ productive and receptive language skills; (ii) it enhances students’ satisfaction with their results; (iii) it fosters one’s motivation to learn a foreign language; (iv) it promotes students’ development as independent learners. It is recommended that this study be extended to the investigation of the impact of such an approach on the students’ final results in ESP in comparable groups.