A. Taal

An improved parametrization of the optical potential for pionic atoms

We extended the parametrization of the phenomenological optical potential for pionic atoms by allowing for an isospin-dependence of the absorption parameters. Least squares fits to the 140 selected pionic atom data are performed. The new parameter set indicates a significant isospin dependence and is able to provide a simultaneous description of shifts and widths for the previously problematic deeply bound 3d-orbits in elements such as 181Ta, natRe, natPt, 197Au, 208Pb and 209Bi.

Authorization of a QoS path based on generic AAA

For data intensive Grid applications, such as shown at iGrid2002, users may require short-lived guaranteed high bandwidth connections. These types of connections, providing a certain Quality of Service (QoS) will need to be authorized and provisioned, often through multiple administrative domains. We present a case study of a Bandwidth on Demand service that provides a QoS path based on Genetic Authorization, Authentication, Accounting, that represents a first step forward towards a multi-domain solution.

A study of the strong interaction effects on pionic 3d and 4f levels in 181Ta, natRe, natPt, 197Au, 208Pb, 209Bi and 237Np

Abstract The pionic X-ray spectra of 181 Ta, nat Re, nat Pt, 197 Au, 208 Pb, 209 Bi and 237 Np have been investigated to obtain data for a systematical study of the pionic 3d and 4f levels. In order to reduce background the experimental method has been improved by using an array of Compton suppression BGO-shields and neutron time-of-flight discrimination. The widths of the pionic 3d levels are observed to be narrower by a factor 1.5 than theoretical predictions obtained with standard optical potentials. A deviation is also found for the strong interaction quadrupole shift, ϵ 2 , for both the 4f and 3d orbits. A possible explanation for the smaller width, Γ 0 (3 d ), can be found by extending the parametrization of the optical potential with absorption terms.

A Software Workbench for Interactive, Time Critical and Highly Self-Adaptive Cloud Applications (SWITCH)

Time critical applications have very high requirements on network and computing services, in particular on well-tuned software architecture with sophisticated optimisation on data communication. Their development is often customised to dedicated infrastructure, and system performance is difficult to maintain when infrastructure changes. This fatal weakness in existing architecture and software tools causes very high development costs, and makes it difficult to fully utilise the virtualised, programmable and quality-on-demand services provided by networked Clouds to improve the system productivity. The Software Workbench for Interactive, Time Critical and Highly self-adaptive Cloud applications (SWITCH) is a newly funded project by EU H2020 to address this urgent industrial need, it aims at improving the existing development and execution model of time critical applications by introducing a novel conceptual model called application-infrastructure co-programming and control model, in which application QoS/QoE together with the programmability and controllability of Cloud environments can be all included in the complete lifecycle of applications.

Using Workflow for Dynamic Security Context Management in Grid-based Applications

This paper presents ongoing research and current results on the development of flexible access control infrastructures for complex resource provisioning in Grid-based collaborative applications and on-demand network services provisioning. We investigate the use of workflow concepts for the required orchestration of multiple Grid resources and/or services across multiple administrative and security domains. In particular, workflow execution and management tools can be used to track security context changes that are dependent on the application domain, execution stage defined policies, or user and/or service attributes. The paper discusses what specific functionality should be added to Grid-oriented authorization frameworks to handle such dynamic service-related security contexts. As an example, the paper explains how such functionality can be achieved in the GAAA Authorization framework and GAAA toolkit. Suggestions are given about integration with the Globus Toolkits Authorization Framework. Additionally, the paper analyses what possibilities of expressing and handling dynamic security contexts are available in XACML and SAML, and how the VO concept can be used for managing dynamic security associations of users and resources. The paper is based on experiences gained from major Grid based and Grid oriented projects such as EGEE, NextGrid, Collaboratory. nl and GigaPort Research on Network.

Strong interaction effects in pionic 208Pb

Abstract The X-ray spectrum of pionic 208 Pb has been measured. The deduced values of the strong interaction monopole shift with respect to the point Coulomb energy are ϵ 0 (4f) = 1.49±0.02 keV and ϵ 0 (3d) = 19.4±1.2 keV. The observed s strong interaction absorption widths of this spherical nucleus are found to be Γ 0 (4f) = 1.25±0.02 keV and Γ 0 (3d) = 47.0±3.6 keV. Important in the analysis of the pionic 4f level is the intensity balance for this level, giving an additional check on the measured absorption width of the pionic 4f level. For the more peripheral 4f state the measured strong interaction shifts and widths are well explained by standard optical model calculations. The values for the 3d state, however, are not in agreement with these calculations.

Planning virtual infrastructures for time critical applications with multiple deadline constraints

Executing time critical applications within cloud environments while satisfying execution deadlines and response time requirements is challenging due to the difficulty of securing guaranteed performance from the underlying virtual infrastructure. Cost-effective solutions for hosting such applications in the Cloud require careful selection of cloud resources and efficient scheduling of individual tasks. Existing solutions for provisioning infrastructures for time constrained applications are typically based on a single global deadline. Many time critical applications however have multiple internal time constraints when responding to new input. In this paper we propose a cloud infrastructure planning algorithm that accounts for multiple overlapping internal deadlines on sets of tasks within an application workflow. In order to better compare with existing work, we adapted the IC-PCP algorithm and then compared it with our own algorithm using a large set of workflows generated at different scales with different execution profiles and deadlines. Our results show that the proposed algorithm can satisfy all overlapping deadline constraints where possible given the resources available, and do so with consistently lower host cost in comparison with IC-PCP.

The quadrupole moment and strong interaction parameters from muonic and pionic X-ray studies of 237Np

Abstract The X-ray spectrum of muonic and pionic 237Np has been investigated with muons and pions stopped in a NpO2 target. The nuclear spectroscopic quadrupole moment was determined to be Q=3.886±0.006 b from the splittings of the muonic 5g→4f hyperfine complexes. The B(E2)↓-values for the first and second excited states were evaluated as 3.17±0.08 and 2.77±0.10 e2b 2, respectively. A comparison between the muonic and pionic 5g→4f hyperfine complexes yields the strong interaction parameters for the pionic 4f state. For the first time a change of sign as function of Z for the strong interaction quadrupole shift ϵ2(4f) has been observed. The standard optical model predictions agree reasonably well with the measured strong interaction monopole optical shift, ϵ0(4f), and width, Г 0 (4f) , while they disagree with the experimental value for ϵ2. A stronger s-wave repulsion in the potential could explain this effect.

A decision framework for placement of applications in clouds that minimizes their carbon footprint

Cloud computing gives users much freedom on where they host their computation and storage. However the CO2 emission of a job depends on the location and the energy efficiency of the data centers where it is run. We developed a decision framework that determines to move computation with accompanying data from a local to a greener remote data center for lower CO2 emissions. The model underlying the framework accounts for the energy consumption at the local and remote sites, as well as of networks among them. We showed that the type of network connecting the two sites has a significant impact on the total CO2 emission. Furthermore, the task’s complexity is a factor in deciding when and where to move computation.

Deadline-Aware Deployment for Time Critical Applications in Clouds

Time critical applications are appealing to deploy in clouds due to the elasticity of cloud resources and their on-demand nature. However, support for deploying application components with strict deadlines on their deployment is lacking in current cloud providers. This is particularly important for adaptive applications that must automatically and seamlessly scale, migrate, or recover swiftly from failures. A common deployment procedure is to transmit application packages from the application provider to the cloud, and install the application there. Thus, users need to manually deploy their applications into clouds step by step with no guarantee regarding deadlines. In this work, we propose a Deadline-aware Deployment System (DDS) for time critical applications in clouds. DDS enables users to automatically deploy applications into clouds. We design bandwidth-aware EDF scheduling algorithms in DDS that minimize the number of deployments that miss their deadlines and maximize the utilization of network bandwidth. In the evaluation, we show that DDS leverages network bandwidth sufficiently, and significantly reduces the number of missed deadlines during deployment.