| 1. |
- Johnsson, Eva, et al.
(författare)
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Den psykosociala integrationens fält.
- 2019
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Ingår i: Det professionella landskapets framväxt. - 9789144122052 ; , s. 261-331
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Svensson, Lennart, et al.
(författare)
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Psykosociala integrationens fält i nutid
- 2019
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Ingår i: Ett professionellt landskap i förvandling. - 9789144122274 ; , s. 217-271
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Abdullah, Matin, et al.
(författare)
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SimDB: A Problem Solving Environment for Molecular Dynamics Simulation and Analysis
- 2000
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Konferensbidrag (refereegranskat)abstract
- The design of a software environment, SimDB, for molecular dynamics simulation and analysis is presented as an example of virtual laboratories enabled by high-speed networks connecting substantial computing and storage resources with more modest local compuation and visualization resources available to research groups. SimDB includes large-scale, dynamic, distributed data repositories. The simulated data sets, trajectories, are usually interpreted through reduced data sets, processed data sets, calculated by analysis functions. Both trajectory data and processed data are saved, but in differnt data bases, with processed data bases having several smaller objects for each trajectory. A browser based user interface with a well defined API allows for a wide array of analysis functions. Analysis functions are executed only if the requested analysis result is not available. The ability to incorporate user defined functions is a critical feature of SimDB.
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| 4. |
- Ahsant, Mehran, et al.
(författare)
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Dynamic, Context-Aware, Least-Privilege Grid Delegation
- 2007
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Ingår i: 8th IEEE/ACM International Conference on Grid Computing. - New York : IEEE. - 9781424415595 ; , s. 209-216
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Konferensbidrag (refereegranskat)abstract
- Performing delegation in large scale, dynamic and distributed environments with large numbers of shared resources is more challenging than inside local administrative domains. In dynamic environments like Grids, on one hand, delegating a restricted set of rights reduces exposure to attack but also limits the flexibility and dynamism of the application; on the other hand, delegating all rights provides maximum flexibility but increases exposure. This issue has not yet been adequately addressed by current Grid security mechanisms and is becoming a very challenging and crucial issue for future Grid development. Therefore, providing an effective delegation mechanism which meets the requirements of the least privilege principle is becoming an essential need. Furthermore, we are witnessing a phenomenal increase in the automation of organizational tasks and decision making, as well as the computerization of information related services, requiring automated delegation mechanisms. In order to meet these requirements we introduce an Active Delegation Framework which extends our previous work on on-demand delegation, making it context-aware. The framework provides a just-in-time, restricted and dynamic delegation mechanism for Grids. In this paper we describe the development of this framework and its implementation and integration with the Globus Toolkit.
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| 5. |
- Ahsant, Mehran, 1974-
(författare)
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On-demand Restricted Delegation : A Framework for Dynamic, Context-Aware, Least-Privilege Delegation in Grids
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In grids, delegation is a key facility that can be used to authenticate and authorize requests on behalf of disconnected users. In current grid systems,delegation is either performed dynamically, in an unrestricted manner, or by a secure but static method. Unfortunately, the former compromises security and the latter cannot satisfy the requirements of dynamic grid application execution. Therefore, development of a delegation framework that enables a restricted and flexible delegation mechanism becomes increasingly urgent as grids are adopted by new communities and grow in size. The main barriers in development of such a mechanism are the requirements for dynamic execution of grid applications, which make it difficult to anticipate required access rights for completing tasks in advance. Another significant architectural requirement in grids is federated security and trust. A considerable barrier to achieving this is cross-organizational authentication and identification. Organizations participating in Virtual Organizations (VOs) may use different security infrastructures that implement different protocols for authentication and identification; thus, there exists a need to provide an architectural mechanism for lightweight, rapid and interoperable translation of security credentials from an original format to a format understandable by recipients. This thesis contributes the development of a delegation framework that utilizes a mechanism for determining and acquiring only required rights and credentials for completing a task, when they are needed. This is what we call an on-demand delegation framework that realizes a bottom-up delegation model and provides a just-in-time acquisition of rights for restricted and dynamic delegation. In this thesis, we further contribute the development of a credential mapping mechanism using off-the-shelf standards and technologies. This mechanism provides support for an on-the-fly exchange of different types of security credentials used by the security mechanisms of existing grids.
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| 6. |
- Ahsant, Mehran, et al.
(författare)
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Toward An On-demand Restricted Delegation Mechanism for Grids
- 2006
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Ingår i: 2006 7TH IEEE/ACM INTERNATIONAL CONFERENCE ON GRID COMPUTING. - New York : IEEE. - 9781424403431 ; , s. 152-159
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Konferensbidrag (refereegranskat)abstract
- Grids are intended to enable cross-organizationalinteractions which makes Grid security a challenging and nontrivialissue. In Grids, delegation is a key facility that canbe used to authenticate and authorize requests on behalf ofdisconnected users. In current Grid systems there is a tradeoffbetween flexibility and security in the context of delegation.Applications must choose between limited or full delegation: onone hand, delegating a restricted set of rights reduces exposure toattack but also limits the flexibility/dynamism of the application;on the other hand, delegating all rights provides maximumflexibility but increases exposure. In this paper, we propose anon-demand restricted delegation mechanism, aimed at addressingthe shortcomings of current delegation mechanisms by providingrestricted delegation in a flexible fashion as needed for Grid applications.This mechanism provides an ontology-based solutionfor tackling one the most challenging issues in security systems,which is the principle of least privileges. It utilizes a callbackmechanism, which allows on-demand provisioning of delegatedcredentials in addition to observing, screening, and auditingdelegated rights at runtime. This mechanism provides supportfor generating delegation credentials with a very limited andwell-defined range of capabilities or policies, where a delegatoris able to grant a delegatee a set of restricted and limited rights,implicitly or explicitly.
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| 7. |
- Ali, Ayaz, et al.
(författare)
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Adaptive Computation of Self Sorting In-place FFTs on Hierarchical Memory Architectures
- 2007
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Ingår i: HIGH PERFORMANCE COMPUTING AND COMMUNICATIONS, PROCEEDINGS. - 9783540754435 ; , s. 372-383
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Konferensbidrag (refereegranskat)abstract
- Computing ”in-place and in-order”FFT poses a very difficult problem on hierarchical memory architectures where data movement can seriously degrade the performance. In this paper we present recursive formulation of a self sorting in-place FFT algorithm that adapts to the target architecture. For transform sizes where an in-place, in-order execution is not possible, we show how schedules can be constructed that use minimum work-space to perform the computation efficiently. In order to express and construct FFT schedules, we present a context free grammar that generates the FFT Schedule Specification Language. We conclude by comparing the performance of our in-place in-order FFT implementation with that of other well known FFT libraries. We also present a performance comparison between the out-of-place and in-place execution of various FFT sizes.
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| 8. |
- Ali, Ayaz, et al.
(författare)
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Empirical Auto-tuning Code Generator for FFT and Trigonometric Transforms
- 2007
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Konferensbidrag (refereegranskat)abstract
- We present an automatic, empirically tuned code genenrator for Real/Complex FFT and Trigonometric Transforms. The code generator is part of an adaptive and portable FFT computation framework - UHFFT. Performance portability over varying architectures is achieved by generating highly optimized set of straight line C codelets (micro-kernel) that adapt to the microprocessor architecture. The tuning is performed by generating several variants of same size codelet with different combinations of optimization parameters. The variants are iteratively compiled and evaluated to find the best implementation on a given platform. Apart from minimizing the operation count, the code generator optimizes for access pattern, register blocking, instruction schedule and structure of arrays. We present details of the optimizations conducted at several stages and the performance gain at each of those levels. We conclude the paper with discussion of the overall performance improvements due to this aggressive approach to generating optimized FFT kernels.
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| 9. |
- Ali, Ayaz, et al.
(författare)
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Scheduling FFT Computation on SMP and Multi-core Systems
- 2007
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Ingår i: Proceedings of the 21st annual international conference on Supercomputing. - New York, NY, USA : ACM. ; , s. 293-301
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Konferensbidrag (refereegranskat)abstract
- Increased complexity of memory systems to ameliorate the gap between the speed of processors and memory has made it increasingly harder for compilers to optimize an arbitrary code within a palatable amount of time. With the emergence of multicore (CMP), multiprocessor (SMP) and hybrid shared memory multiprocessor architectures, achieving high e ciency is becoming even more challenging. To address the challenge to achieve high e ciency in performance critical applications, domain speci c frameworks have been developed that aid the compilers in scheduling the computations. We have developed a portable framework for the Fast Fourier Transform (FFT) that achieves high e ciency by automatically adapting to various architectural features. Adapting to parallel architectures by searching through all the combinations of schedules (plans) is an expensive task, even when the search is conducted in parallel. In this paper, we develop heuristics to simplify the generation of better schedules for parallel FFT computations on CMP/SMP systems. We evaluate the performance of OpenMP and PThreads implementations of FFT on a number of latest architectures. The performance of parallel FFT schedules is compared with that of the best plan generated for sequential FFT and the speedup for di erent number of processors is reported. In the end, we also present a performance comparison between the UHFFT and FFTW implementations.
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| 10. |
- Andersson, Lennart, et al.
(författare)
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Praktikfall i reglerteknik - Råspritbränneriet i Nöbbelöv
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- During spring 1998 the course Industrial Case Studies in Control was given at the Department of Automatic Control in Lund. The course consisted of a project at an industry with control applications. This report considers a project at the crude alcohol distillery in Nöbbelöv, where the base product for the liquor Absolut Vodka is produced. The distillery had problems with fluctuations in the concentration of ethanol in the crude alcohol. The purpose of the project was to analyze the cause of the fluctuations, and if possibly eliminate it. The fluctuations were cause by an output limiter on a controller, and were relatively easily eliminated. To examine if control performance could be further improved, a series of experiments was carried out on the plant. The result of the experiments were then used to derive a simple process model, and a suggestion for new controller parameters.
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