1,653 research outputs found
End-to-End QoS Support for a Medical Grid Service Infrastructure
Quality of Service support is an important prerequisite for the adoption of Grid technologies for medical applications. The GEMSS Grid infrastructure addressed this issue by offering end-to-end QoS in the form of explicit timeliness guarantees for compute-intensive medical simulation services. Within GEMSS, parallel applications installed on clusters or other HPC hardware may be exposed as QoS-aware Grid services for which clients may dynamically negotiate QoS constraints with respect to response time and price using Service Level Agreements. The GEMSS infrastructure and middleware is based on standard Web services technology and relies on a reservation based approach to QoS coupled with application specific performance models. In this paper we present an overview of the GEMSS infrastructure, describe the available QoS and security mechanisms, and demonstrate the effectiveness of our methods with a Grid-enabled medical imaging service
Charge-Spin Separation in 2D Fermi Systems: Singular Interactions as Modified Commutators, and Solution of 2D Hubbard Model in Bosonized Approximation
The general 2-dimensional fermion system with repulsive interactions
(typified by the Hubbard Model) is bosonized, taking into account the finite
on-shell forward scattering phase shift derived in earlier papers. By taking
this phase shift into account in the bosonic commutation relations a consistent
picture emerges showing the charge-spin separation and anomalous exponents of
the Luttinger liquid.Comment: Latex file 14 pages. email: [email protected]
BCS-to-BEC crossover from the exact BCS solution
The BCS-to-BEC crossover, as well as the nature of Cooper pairs, in a
superconducting and Fermi superfluid medium is studied from the exact ground
state wavefunction of the reduced BCS Hamiltonian. As the strength of the
interaction increases, the ground state continuously evolves from a
mixed-system of quasifree fermions and pair resonances (BCS), to pair
resonances and quasibound molecules (pseudogap), and finally to a system of
quasibound molecules (BEC). A single unified scenario arises where the
Cooper-pair wavefunction has a unique functional form. Several exact analytic
expressions, such as the binding energy and condensate fraction, are derived.
We compare our results with recent experiments in ultracold atomic Fermi gases.Comment: 5 pages, 4 figures. Revised version with one figure adde
Occurrence and Transmission of Grapevine Virus A in South African grapevines
Antiserum prepared to a local isolate of grapevine virus A (GVA) was used in immunosorbent electron microscopy (ISEM) with decoration and in an unlabelled antibody enzyme-linked immunosorbent assay (ELISA) for the screening of grapevine sources for the presence of virus. GV A occurred extensively in grapevine plantings showing visual symp· toms of leafroll or indexing positive for leafroll. GV A was found not to be associated with either stem pitting or fleck symptoms. It occurred mostly in association with undecorated closterovirus (CV)-like particles. Limited ISEM with decoration of the CV-like particles using antiserum to a Swiss isolate of CV 2 200 nm, (CV type I) confirmed the presence of a second CV in local grapevine sources. In addition, it indicated the presence of a third CV -like particle longer than GVA. GVA together with undecorated CV-like particles were also detected in initially GVA-free LN-33 grapevines growing under field conditions and naturally infected with Ieafroll. GV A and CV type I were also present in the vine mealybug Planococcus ficus, following exposure to a grapevine source carrying these viruses. H'lwever, due to lack of CV type I antiserum, only GV A was confirmed in grapevine following controlled transmissions with P. ficus although undecorated CV -like particles were present. The reliability of the ELISA detection procedure appears to be influenced by seasonal fluctuations in GV A concentrations
Successfully implementing a Manufacturing Execution Systems (MES) solutions.
Thesis (MBA)-University of KwaZulu-Natal, 2007.A Manufacturing Execution System (MES) is a system that companies use to measure and control critical production activities. As the installed base of MES installations grows, claims that MES does not have a positive impact on the day-to-day operations within manufacturing companies are more common. Documented results and anecdotal evidence are also now available. Due to the pace at which this market has grown, more and more vendors and implementation partners are entering the market. Organizations that wish to successfully implement a MES solution need to be well informed and educated about the intricacies of software implementations. Organizations need to ensure that they are in control of the implementation and not at the mercy of the software vendors and implementation partners for success. Organizations need to plan the whole implementation process thoroughly and top level management need to drive the initiatives within the organization to ensure success
N,N-Bis(diphenylphosphanyl)cyclopentanamine
The coordination around the N atom in the title compound, C29H29NP2, shows an almost planar geometry, defined by the attached P and C atoms, in order to accomodate the steric bulk of the phenyl rings. The distortion of the trigonal–pyramidal geometry of the N atom is illustrated by the bond angles ranging between 115.22 (12) and 121.76 (9)°. The P atoms present a pyramidal environment with bond angles ranging from 100.62 (9) to 104.71 (8)°. One of the C atoms in the cyclopentyl ring displays a 0.822 (4):0.178 (4) positional disorder. Within the crystal structure, intramolecular C—H⋯P hydrogen bonds together with inter- and intramolecular C—H⋯π interactions link the molecules into a supramolecular two-dimensional network
N,N-Bis(diphenylphosphanyl)cyclopropylamine
In the title compound, C27H25NP2, the diphenylphosphino groups are staggered relative to the PNP backbone. The dihedral angles between the phenyl rings bonded to each P atom are 51.74 (5) and 68.23 (4)°. The coordination around the N atom deviates from trigonal-pyrimidal geometry towards an almost planar arrangement between the N atom and the adjacent P and C atoms; the distance between the N atom and the plane formed by the adjacent C/P/P atoms is 0.098 (2) Å
N,N-Bis(diphenylphosphanyl)cyclobutanamine
In the title compound, C28H27NP2, the N atom adopts an almost planar geometry with the two P atoms and the C atom attached to it, with a distance of 0.066 (2) Å between the N atom and the C/P/P plane. The distorted trigonal–pyramidal geometry of the N atom is further illustrated by bond angles ranging between 115.22 (11) and 123.53 (8)°. Bond angles varying from 99.99 (9) to 108.07 (9) ° are indicative of the distorted pyramidal environment around the P atoms. An intramolecular C—H⋯P hydrogen bond occurs. In the crystal, intermolecular C—H⋯π interactions link the molecules into a supramolecular network
Lived experiences of a community regarding its involvement in a university community-based education programme
BACKGROUND: Community involvement is one of the crucial principles in the implementation of successful community-based education programmes. However, a gap continues to exist between the rhetoric of this principle and the reality of involving or engaging communities in the education of health professionals. OBJECTIVES: This study investigated the experiences of a community regarding its involvement in a community-based education programme offered by a university nursing school in Durban, South Africa. METHODS: An interpretive existentialist-phenomenological design was employed for its richness in extracting human experiences. Individual interviews were held with school teachers and coordinators from non-government organisations, whilst focus groups were used for school children and community health workers. Although focus group discussions are not well suited for phenomenological studies, they can promote active participation and reduce possible intimidation by providing support through group interaction. Analysis of data was guided by Schweitzer’s model for analysing phenomenological data. RESULTS: Themes that emerged from the data include: (1) Community experience of unmet expectations; (2) Benefits to the community from its involvement in the University Nursing School community-based education programme; (3) Existing partnership between the community and the university; (4) Sharing in the case-based learning activities; (5) Awareness of available services, human rights and self-reliance.CONCLUSION: The researched community indeed benefited in its participation in the University Nursing School (UNS) CBE programme. However, there is a need to improve the communication between partners to make the partnership more sustainable through close relationships and interaction. There is also a need for further research on related aspects of the community’s involvement. Introduction Community involvement is one of the crucial principles in the implementation of community basedDepartment of HE and Training approved lis
Seeking multiple solutions:an updated survey on niching methods and their applications
Multi-Modal Optimization (MMO) aiming to locate multiple optimal (or near-optimal) solutions in a single simulation run has practical relevance to problem solving across many fields. Population-based meta-heuristics have been shown particularly effective in solving MMO problems, if equipped with specificallydesigned diversity-preserving mechanisms, commonly known as niching methods. This paper provides an updated survey on niching methods. The paper first revisits the fundamental concepts about niching and its most representative schemes, then reviews the most recent development of niching methods, including novel and hybrid methods, performance measures, and benchmarks for their assessment. Furthermore, the paper surveys previous attempts at leveraging the capabilities of niching to facilitate various optimization tasks (e.g., multi-objective and dynamic optimization) and machine learning tasks (e.g., clustering, feature selection, and learning ensembles). A list of successful applications of niching methods to real-world problems is presented to demonstrate the capabilities of niching methods in providing solutions that are difficult for other optimization methods to offer. The significant practical value of niching methods is clearly exemplified through these applications. Finally, the paper poses challenges and research questions on niching that are yet to be appropriately addressed. Providing answers to these questions is crucial before we can bring more fruitful benefits of niching to real-world problem solving
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