Extension of Affine Shape

In this paper, we extend the notion of affine shape, introduced by Sparr, from finite point sets to more general sets. It turns out to be possible to generalize most of the theory. The extension makes it possible to reconstruct, for example, 3D-curves up to projective transformations, from a number of their 2D-projections. An algorithm is presented, which is independent of choice of coordinates, is robust, does not rely on any preselected parameters and works for an arbitrary number of images. In particular this means that a solution is given to the aperture problem of finding point correspondences between curves.     

The Brave New World of development in the internetwork computing architecture (InterNCA): or how distributed computing platforms will change systems development

This essay is a speculation of the impact of the next generation technological platform — the internetwork computing architecture (InterNCA) — on systems development. The impact will be deep and pervasive and more substantial than when computing migrated from closed computer rooms to ubiquitous personal computers and flexible client-server solutions. Initially, by drawing upon the notion of a technological frame, the InterNCA, and how it differs from earlier technological frames, is examined. Thereafter, a number of hypotheses are postulated with regard to how the architecture will affect systems development content, scope, organization and processes. Finally, some suggestions for where the information systems research community should focus its efforts (if the call for relevance is not to be taken lightly) are proposed.     

Further consideration of the effect of curvature on the stability of three-dimensional flows

The effect of curvature on the stability and transition of three-dimensional incompressible flows is examined. The stability equations with and without curvature terms are solved with the temporal eigenvalue formulations used by Malik and Poll. Calculations are performed for flow over a yawed circular cylinder and results are compared with the calculations of Malik and Poll with and without curvature effects. Results show that the effect of curvature on transition is much smaller than claimed previously.     

Groups are not always the same

The idea of supporting group meetings at the same time and at the same place by computer raises the problem of how salient features of group behaviors are understood in meetings. In this paper we take a critical look at several beliefs about group behaviors in research dealing with electronic meeting systems (EMS). The paper argues based on an empirical study that the concept of a small, cohesive business team, so widely held, in all EMS research is not necessarily a valid starting point in thinking of meeting support. In particular, the paper critically evaluates a number of beliefs of user aspects, group features such as composition, structure and protocols, and task characteristics such as nature, importance and meeting goals. In consequence, if these prominent features can vary markedly all meeting support cannot be designed in ways envisaged in current research. In conclusion we outline some research questions—both of empirical and constructive nature—that need to be addressed if the EMS research wants to address issues in computer support in groups that are not similar with business teams.An earlier version of this paper was presented at 25th HICSS conference, 10–12.1.1993.This research was in part funded by the Academy of Finland.The opinions presented in this work are not official statements of any of the participating organizations.This research was in part funded by the Finnish Technology Development Center     

Optimisation strategies introduced for CR at health care centres in Estonia

In recent years, starting from 2001, conventional film-screen radiography has been rapidly replaced by digital (mostly by computed radiography, CR) techniques in Estonia. New strategies for optimisation and quality assurance for digital radiography have been introduced by the DIMOND III and SENTINEL partners recently. It includes consideration to diagnostic requirements of a given clinical situation, but also objectivation and standardisation of image quality, e.g. using CDRAD test phantom, and constancy testing. The aim of this work is to evaluate the performance of an automatic exposure control (AEC) at different sensitivities when used with the Fujifilm CR system. Image quality, using threshold contrast-detail detectability (TCDD) and signal-to-noise ratio squared related to dose (SNR(2)/D), was also investigated for different sensitivities and tube potential values for this combination. Based on the image evaluation data, optimum speed modes for the organ programme settings have been proposed.     

洗涤剂酶的最近进展和21世纪的展望

论述了洗涤剂酶的发展趋向。生物工程，基因工程，蛋白质工程及定向分子演变在酶的新品开发和性能改进方面的应用。酶在整体洗涤效果方面的作用除了易于清除直接附着在织物表面的污垢外，还有消除微纤维。短毛和小球的作用。改善织物表面的色泽，清除微粒的残余污垢和保持织物白度，防止织物发灰以及减轻微粒污垢的再沉积作用。     

Electrically conducting compound synthesized from lignin and sulfur

Summary A thermostable polymer, called sulfur lignin, has been obtained when modifying lignin by reactions with elemental sulfur at elevated temperatures. Sulfur linkages are formed between the phenylpropane units of lignin in these reactions. The conductivity of polymers which have a conjugated structure can be increased by doping with electron acceptors or donors. The conductivity of sulfur lignin has been measured after doping with various dopants and from the results it is concluded that the doped sulfur lignin has the properties off a semi conductive polymer.