1,006 research outputs found
Aligning system requirements with stakeholder concerns : use of case studies and patterns to capture domain experience
Traditionally system development starts with the specification of system requirements. The focus of such an approach is on the system under construction, which is considered as of primary importance to the development success. The major problem with such an approach, however, is the neglect of concerns held by the various system stakeholders, whose opinions, loyalties and fears may impact considerably the perception and the reception of the implemented system, its functions and its features. Typically, stakeholder concerns are not collected or identified, and are viewed as of little significance in the system development process. In this paper, however, we present the case for recognising the value of stakeholder concerns, and their use in aligning business needs with system requirements. We describe a method of gathering and analysing stakeholder concerns across an application domain, and then packaging the development experience in dealing with these concerns into patterns. Experience patterns can subsequently be used to guide systems analysts in selecting the most appropriate requirements for the target stakeholder community.<br /
Applying domain analysis to the investigation of web-enabled human resource projects
Designing a successful web project requires understanding not only of its owner\u27s business and technological needs, as well as having the substantial management and development experience, but it also depends on a thorough knowledge of the system\u27s application domain and of other existing systems in the domain. In order to gather such domain knowledge, it is necessary to identify the nature of the proposed web services venture with regards to other similar services offered in the domain, the business setting of enterprises that initiate such ventures, the various types of customers involved, and how these factors translate into requirements. In this paper, we present an approach to studying the domain of web-enabled Human Resource and payroll services with the aim of attaining design knowledge that would ensure customer satisfaction and could eventually pave the way to the successful implementation of web-enabled services.<br /
Analysis of stakeholder concerns with a view to avoid organisational conflict in B2B systems
In recent years there has been a remarkable increase in information exchange between organizations due to changes in market structures and new forms of business relationships. The increase in the volume of business-to-business (B2B) transactions has contributed significantly to the expanding need for electronic systems that could effectively support communication between collaborating organizations. Examples of such collaborating systems include those that offer various types of business-to-business services, e.g. electronic commerce, electronic procurement systems, electronic links between legacy systems, or outsourced systems providing data processing services via electronic media. Development and running of B2B electronic systems has not been problem free. One of the most intractable issues found in B2B systems is the prevalence of inter-organisational conflict reported to exist and persists between the participants of interorganisational electronic networks. There have been very few attempts, however, to prescribe any practical method of detecting the antecedents of such conflict early in B2B development to facilitate smooth construction and the subsequent operation of B2B services. The research reported in this paper focuses on the identification and analysis of antecedent conflict in a joint process involving different organizations in a B2B venture. The proposed method involves identification of domain stakeholders, capturing and packaging their views and concerns into a reusable form, and the application of captured domain experience in B2B systems development. The concepts and methods introduced in this paper have been illustrated with examples drawn from our study of six web-enabled payroll systems.<br /
Room temperature regioselective catalytic hydrodefluorination of fluoroarenes with trans-[Ru(NHC)4H2] through a concerted nucleophilic Ru−H attack pathway
The authors acknowledge the EPSRC (grant EP/J009962/1, DTA) for financial supportThe efficient and highly selective room temperature hydrodefluorination (HDF) of fluoroarenes by the trans-[Ru(IMe4)4H2] catalyst, 3 , is reported. Mechanistic studies show 3 acts directly in catalysis without any ligand dissociation and DFT calculations indicate a concerted nucleophilic attack mechanism. The calculations fully account for the observed selectivities which corroborate earlier predictions regarding the selectivity of HDF.PostprintPeer reviewe
Unexpected Vulnerability of DPEphos to C-O Activation in the Presence of Nucleophilic Metal Hydrides
C−O bond activation of DPEphos occurs upon mild heating in the presence of [Ru(NHC)2(PPh3)2H2] (NHC=N-heterocyclic carbene) to form phosphinophenolate products. When NHC=IEt2Me2, C−O activation is accompanied by C−N activation of an NHC ligand to yield a coordinated N-phosphino-functionalised carbene. DFT calculations define a nucleophilic mechanism in which a hydride ligand attacks the aryl carbon of the DPEphos C−O bond. This is promoted by the strongly donating NHC ligands which render a trans dihydride intermediate featuring highly nucleophilic hydride ligands accessible. C−O bond activation also occurs upon heating cis-[Ru(DPEphos)2H2]. DFT calculations suggest this reaction is promoted by the steric encumbrance associated with two bulky DPEphos ligands. Our observations that facile degradation of the DPEphos ligand via C−O bond activation is possible under relatively mild reaction conditions has potential ramifications for the use of this ligand in high-temperature catalysis.</p
Westerbork Ultra-Deep Survey of HI at z=0.2
In this contribution, we present some preliminary observational results from
the completed ultra-deep survey of 21cm emission from neutral hydrogen at
redshifts z=0.164-0.224 with the Westerbork Synthesis Radio Telescope. In two
separate fields, a total of 160 individual galaxies has been detected in
neutral hydrogen, with HI masses varying from 1.1x10^9 to 4.0x10^10 Msun. The
largest galaxies are spatially resolved by the synthesized beam of 23x37
arcsec^2 while the velocity resolution of 19 km/s allowed the HI emission lines
to be well resolved. The large scale structure in the surveyed volume is traced
well in HI, apart from the highest density regions like the cores of galaxy
clusters. All significant HI detections have obvious or plausible optical
counterparts which are usually blue late-type galaxies that are UV-bright. One
of the observed fields contains a massive Butcher-Oemler cluster but none of
the associated blue galaxies has been detected in HI. The data suggest that the
lower-luminosity galaxies at z=0.2 are more gas-rich than galaxies of similar
luminosities at z=0, pending a careful analysis of the completeness near the
detection limit. Optical counterparts of the HI detected galaxies are mostly
located in the 'blue cloud' of the galaxy population although several galaxies
on the 'red sequence' are also detected in HI. These results hold great promise
for future deep 21cm surveys of neutral hydrogen with MeerKAT, APERTIF, ASKAP,
and ultimately the Square Kilometre Array.Comment: 10 pages, 9 figures, Proceedings of ISKAF2010 Science Meeting: A New
Golden Age for Radio Astronomy, June 10-14 2010, Assen, the Netherlands.
Edited by J. van Leeuwen. Movies of rendered rotating data cubes are
available at http://www.astro.rug.nl/~verheyen/BUDHIES/index.htm
Computation Provides Chemical Insight into the Diverse Hydride NMR Chemical Shifts of [Ru(NHC)<sub>4</sub>(L)H]<sup>0/+</sup> Species (NHC = N-heterocyclic carbene; L = vacant, H<sub>2</sub>, N<sub>2</sub>, CO, MeCN, O<sub>2</sub>, P<sub>4</sub>, SO<sub>2</sub>, H<sup>-</sup>, F<sup>-</sup> and Cl<sup>-</sup>) and their [Ru(R<sub>2</sub>PCH<sub>2</sub>CH<sub>2</sub>PR<sub>2</sub>)<sub>2</sub>(L)H]<sup>+</sup> Congeners
Relativistic density functional theory calculations, both with and without the effects of spin–orbit coupling, have been employed to model hydride NMR chemical shifts for a series of [Ru(NHC)4(L)H]0/+ species (NHC = N-heterocyclic carbene; L = vacant, H2, N2, CO, MeCN, O2, P4, SO2, H−, F− and Cl−), as well as selected phosphine analogues [Ru(R2PCH2CH2PR2)2(L)H]+ (R = iPr, Cy; L = vacant, O2). Inclusion of spin–orbit coupling provides good agreement with the experimental data. For the NHC systems large variations in hydride chemical shift are shown to arise from the paramagnetic term, with high net shielding (L = vacant, Cl−, F−) being reinforced by the contribution from spin–orbit coupling. Natural chemical shift analysis highlights the major orbital contributions to the paramagnetic term and rationalizes trends via changes in the energies of the occupied Ru dπ orbitals and the unoccupied σ*Ru–H orbital. In [Ru(NHC)4(η2-O2)H]+ a δ-interaction with the O2 ligand results in a low-lying LUMO of dπ character. As a result this orbital can no longer contribute to the paramagnetic shielding, but instead provides additional deshielding via overlap with the remaining (occupied) dπ orbital under the Lz angular momentum operator. These two effects account for the unusual hydride chemical shift of +4.8 ppm observed experimentally for this species. Calculations reproduce hydride chemical shift data observed for [Ru(iPr2PCH2CH2PiPr2)2(η2-O2)H]+ (δ = −6.2 ppm) and [Ru(R2PCH2CH2PR2)2H]+ (ca. −32 ppm, R = iPr, Cy). For the latter, the presence of a weak agostic interaction trans to the hydride ligand is significant, as in its absence (R = Me) calculations predict a chemical shift of −41 ppm, similar to the [Ru(NHC)4H]+ analogues. Depending on the strength of the agostic interaction a variation of up to 18 ppm in hydride chemical shift is possible and this factor (that is not necessarily readily detected experimentally) can aid in the interpretation of hydride chemical shift data for nominally unsaturated hydride-containing species. The synthesis and crystallographic characterization of the BArF4− salts of [Ru(IMe4)4(L)H]+ (IMe4 = 1,3,4,5-tetramethylimidazol-2-ylidene; L = P4, SO2; ArF = 3,5-(CF3)2C6H3) and [Ru(IMe4)4(Cl)H] are also reported
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