Towards Information Systems Design for Value Webs

In this paper we discuss the alignment between a business model of a value web and the information systems of the participating companies needed to implement the business model. Traditional business-IT alignment approaches\ud focus on one single company, but in a value web we are dealing with various independent businesses. Since a value web is actually a web of services, delivered by IT systems owned by different companies, to ensure alignment we need to\ud specify the services and their properties and then map them on the available IT support in the different companies. Such mappings have to be evaluated in terms of their impact on the profitability of participating in the value web of the different companies. We propose techniques to map services to IT support and show how to do commercial trade-offs

Microstates of a Neutral Black Hole in M Theory

We consider vacuum solutions in M theory of the form of a five-dimensional Kaluza-Klein black hole cross T^6. In a certain limit, these include the five-dimensional neutral rotating black hole (cross T^6). From a IIA standpoint, these solutions carry D0 and D6 charges. We show that there is a weakly coupled D-brane description which precisely reproduces the Hawking-Bekenstein entropy in the extremal limit, even though supersymmetry is completely broken.Comment: 11 pages. v2: microstate counting extended to generic angular moment

Discovery and Selection of Certified Web Services Through Registry-Based Testing and Verification

Reliability and trust are fundamental prerequisites for the establishment of functional relationships among peers in a Collaborative Networked Organisation (CNO), especially in the context of Virtual Enterprises where economic benefits can be directly at stake. This paper presents a novel approach towards effective service discovery and selection that is no longer based on informal, ambiguous and potentially unreliable service descriptions, but on formal specifications that can be used to verify and certify the actual Web service implementations. We propose the use of Stream X-machines (SXMs) as a powerful modelling formalism for constructing the behavioural specification of a Web service, for performing verification through the generation of exhaustive test cases, and for performing validation through animation or model checking during service selection

Value-based Requirements Engineering for Value Webs

Since the 1980s, requirements engineering (RE) for information systems has been performed in practice using techniques (rather than the full method) from Information Engineering (IE) such as business goal analysis, function{ and process modeling, and cluster analysis. Recently, these techniques have been supplemented with portfolio management, which looks at sets of IT projects and offers fast quantitative decision-making about continuation of IT projects. Today's networked world, though, poses challenges to these techniques. A major drawback is their inability to adequately specify the requirements for IT systems used by businesses that provide services to each other in a value web. In this paper, we analyze this problem, and propose a solution by coupling IE and portfolio management with value-based RE techniques at the business network level. We show how these techniques interrelate, and illustrate our approach with a small example

HI in Abell 3128

We discuss Australia Telescope Compact Array (ATCA) HI 21cm data for the galaxy cluster A3128. Our observations are intentionally relatively shallow, and a blind search through our data cube yields (tentative) detections of only two galaxies, of which one is probably spurious. A3128 is part of the ESO Nearby Abell Cluster Survey (ENACS); redshifts are available for 193 galaxies in the A3128 region. For 148 of these galaxies the redshifts are such that the HI emission (if any) would lie within our data cube. We use the known redshifts of these galaxies to coadd their spectra and thus improve our sensitivity to HI emission. The technique is fairly successful -- the coadded spectra allow detection of an average mass content of ~ 9x10^8 Msun, almost an order of magnitude lower than for direct detection of individual objects. By dividing the total galaxy sample into subsamples we find that the gas content of late type galaxies that lie outside the X-ray emitting core of the cluster is substantially higher than that of those within the core. Even outside the X-ray emitting region the distribution of gas-rich galaxies in the cluster is not uniform, we find that gas-rich galaxies are concentrated in the east of the cluster. This is consistent with earlier analyses of the kinematics of the galaxies in A3128 which indicate the presence of subclustering. In summary we find that coadding spectra is a powerful tool for the study of HI in cluster galaxies, and suggest that this technique could be applied to substantially increase the redshift range over which such observations could be carried out.Comment: 8pages, 7 figures accepted for publication in A&

PoN-S : a systematic approach for applying the Physics of Notation (PoN)

Visual Modeling Languages (VMLs) are important instruments of communication between modelers and stakeholders. Thus, it is important to provide guidelines for designing VMLs. The most widespread approach for analyzing and designing concrete syntaxes for VMLs is the so-called Physics of Notation (PoN). PoN has been successfully applied in the analysis of several VMLs. However, despite its popularity, the application of PoN principles for designing VMLs has been limited. This paper presents a systematic approach for applying PoN in the design of the concrete syntax of VMLs. We propose here a design process establishing activities to be performed, their connection to PoN principles, as well as criteria for grouping PoN principles that guide this process. Moreover, we present a case study in which a visual notation for representing Ontology Pattern Languages is designed

"Hiccup" accretion in the swinging pulsar IGR J18245-2452

IGR J18245-2452 is the fifteenth discovered accreting millisecond X-ray pulsar and the first source of this class showing direct evidence for transition between accretion and rotational powered emission states. These swing provided the strongest confirmation of the pulsar recycling scenario available so far. During the two XMM-Newton observations that were carried out while the source was in outburst in April 2013, IGR J18245-2452 displayed a unique and peculiar variability of its X-ray emission. In this work, we report on a detailed analysis of the XMM- Newton data and focus in particular on the timing and spectral variability of the source. IGR J18245-2452 continuously switches between lower and higher intensity states, with typical variations in flux up to a factor of about 500 in time scales as short as few seconds. These variations in the source intensity are sometimes associated to a dramatic spectral hardening, during which the power-law photon index of the source changes from Gamma=1.7 to Gamma=0.9. The pulse profiles extracted at different count rates and energies show a complex variability. These phenomena are not usually observed in accreting millisecond X-ray pulsars, at least not on such a short time scale. Fast variability was also found in the ATCA radio observations carried out for about 6 hours during the outburst at a frequency of 5.5 and 9 GHz. We interpret the variability observed from IGR J18245-2452 in terms of a "hiccup" accretion phase, during which the accretion of material from the inner boundary of the Keplerian disk is reduced by the onset of centrifugal inhibition of accretion, possibly causing the launch of strong outflows. Changes across accretion and propeller regimes have been long predicted and reproduced by MHD simulations of accreting millisecond X-ray pulsars but never observed to produce an extreme variability as that shown by IGR J18245-2452.Comment: A&A in press. Revised versio

HI Emission and Absorption in the Southern Galactic Plane Survey

We present preliminary results from the Southern Galactic Plane Survey (SGPS) Test Region and Parkes data. As part of the pilot project for the Southern Galactic Plane Survey, observations of a Test Region (325.5 deg < l < 333.5 deg; -0.5 deg < b < 3.5 deg) were completed in December 1998. Single dish observations of the full survey region (253 deg < l < 358 deg; |b| <1 deg) with the Parkes Radio Telescope were completed in March 2000. We present a sample of SGPS HI data with particular attention to the smallest and largest scale structures seen in absorption and emission, respectively. On the large scale, we detect many prominent HI shells. On the small scale, we note extremely compact, cold clouds seen in HI self-absorption. We explore how these two classes of objects probe opposite ends of the HI spatial power spectrum.Comment: 9 pages, 3 embedded postscript & 4 jpeg figures. Presented at the Astronomical Society of Australia, Hobart, Tasmania, July 4-7 2000. To appear in PASA Vol. 18(1

An integrated conceptual model for information system security risk management supported by enterprise architecture management

Risk management is today a major steering tool for any organisation wanting to deal with information system (IS) security. However, IS security risk management (ISSRM) remains a difficult process to establish and maintain, mainly in a context of multi-regulations with complex and inter-connected IS. We claim that a connection with enterprise architecture management (EAM) contributes to deal with these issues. A first step towards a better integration of both domains is to define an integrated EAM-ISSRM conceptual model. This paper is about the elaboration and validation of this model. To do so, we improve an existing ISSRM domain model, i.e. a conceptual model depicting the domain of ISSRM, with the concepts of EAM. The validation of the EAM-ISSRM integrated model is then performed with the help of a validation group assessing the utility and usability of the model