BRIL - Capturing Experiments in the Wild

This presentation describes a project to embed a repository system (based on Fedora) within the complex, experimental processes of a number of researchers in biophysics and structural biology. The project is capturing not just individual datasets but entire experimental workflows as complex objects, incorporating provenance information based on the Open Provenance Model, to support reproduction and validation of published results. The repository is integrated within these experimental processes, so that data capture is as far as possible automatic and invisible to the researcher. A particular challenge is that the researchers’ work takes place in local environments within the department, entirely decoupled from the repository. In meeting this challenge, the project is bridging the gap between the “wild”, ad hoc and independent environment of the researchers desktop, and the curated, sustainable, institutional environment of the repository, and in the process project crosses the boundary between several of the pairs of polar opposites identified in the call

Provenance support for service-based infrastructure

Service-based architectures represent the next evolutionary step in the development of e-science, namely, the transformation of the Internet from a commercial marketplace to a mechanism for sharing multidisciplinary scientific resources. Although scientists in many disciplines have become increasingly reliant on distributed computing technologies for data processing and dissemination, the record of the processing history and origin of a data product, that is its data provenance, is often nonexistent, incomplete or impossible to recover by potential users. This thesis aims to address data provenance issues in service-based environments, particularly to answer how a scientist who performs a workflow execution in such an environment can (1) document the data provenance for a data item created by the execution, and (2) use the provenance documentation as a recipe to re-execute the workflow. This thesis pro poses a provenance model for delivering data provenance support in a service-based environment. Through the use of an example scenario of a scientific workflow in the Astrophysics domain, we explore and identify components of the provenance model. The provenance model proposes a technique to collect and record data provenance for service-based workflow executions. The technique facilitates the collection of data provenance of workflow execution at runtime. In order to record the collected data provenance, the thesis also proposes a specification to represent provenance to de scribe the processing history whereby a piece of data was derived. The thesis also proposes query interfaces that allow recorded provenance to be queried, has formulated a technique to construct provenance graphs, and supports the re-execution of past workflows. The provenance representation specification, the collection technique, and the query interfaces have been used to implement a prototype system to demonstrate the proposed model. The thesis also experimentally evaluates the scalability of the components implemented.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A Reconfigurable Approximate JPEG Encoder Implemented On FPGA Platform

Approximate computing is a blooming field of research, which involves a compro- mise of an application’s accuracy to make it more efficient. It necessarily involves a deliberate effort to make an application imprecise in order to conserve some re- source. While the techniques for approximation may include using approximate functional units, approximate storage hardware, approximate network communica- tion or executing algorithms with varying precision, in this thesis, we mainly aim to use approximate arithmetic units in a JPEG Encoder Core. Using imprecise arithmetic units requires an identification of the applications which are resilient to errors. JPEG compression is inherently a lossy compression as the degradation in image quality isn’t perceptible to the end users for a significant compression ratio. This tolerance of JPEG compression to a loss of data is exploited to replace the accurate computationally intensive blocks of the JPEG encoding algo- rithm with their imprecise counterparts. The approximate hardware design proposed in this thesis is also reconfigurable, which implies that the end user can select the level of approximation desired based on the loss in accuracy allowed. The reconfigurable approximate JPEG hardware is also implemented on the FPGA platform. The FPGA emulation of the approximate and the precise ver- sions of the JPEG Encoder core is done on the Altera DE1-SoC with Cyclone V device and an ARM based Hard Processor System. The emulation provided a max- imum area reduction by 45%, maximum delay reduction by 29% and a maximum power reduction by 28% for an approximation of 8 least significant bits. For approx- imation of more than 8 least significant bits, the peak-signal-to-noise ratio of the decompressed image is very low, resulting in poor image quality

BRIL - Capturing Experiments in the Wild

This presentation describes a project to embed a repository system (based on Fedora) within the complex, experimental processes of a number of researchers in biophysics and structural biology. The project is capturing not just individual datasets but entire experimental workflows as complex objects, incorporating provenance information based on the Open Provenance Model, to support reproduction and validation of published results. The repository is integrated within these experimental processes, so that data capture is as far as possible automatic and invisible to the researcher. A particular challenge is that the researchers’ work takes place in local environments within the department, entirely decoupled from the repository. In meeting this challenge, the project is bridging the gap between the “wild”, ad hoc and independent environment of the researchers desktop, and the curated, sustainable, institutional environment of the repository, and in the process project crosses the boundary between several of the pairs of polar opposites identified in the call

Optimal Power Flow Solution in Smart Grid Environment Using SVC and TCSC

Flexible AC transmission system devices (FACTS) are most promising controllers in present day scenario when it comes to power transmission in long distances in smart grids. FACTS devices provide system stability, midpoint voltage support and reactive power control in grid interconnections. Conventionally, power flow algorithm was used to evaluate the rating of FACTS devices by taking consideration of magnitude of voltage and phase angle as independent variables. Nowadays, FACTS device rating is evaluated with a new framework called optimal power flow. This chapter provides a comparison for optimal power flow, with or without FACTS devices such as static VAR compensator (SVC) and thyristor controlled series capacitor (TCSC), in terms of cost saving and loss reduction in smart grid scenario

Provenance support for service-based infrastructure

Service-based architectures represent the next evolutionary step in the development of e-science, namely, the transformation of the Internet from a commercial marketplace to a mechanism for sharing multidisciplinary scientific resources. Although scientists in many disciplines have become increasingly reliant on distributed computing technologies for data processing and dissemination, the record of the processing history and origin of a data product, that is its data provenance, is often nonexistent, incomplete or impossible to recover by potential users. This thesis aims to address data provenance issues in service-based environments, particularly to answer how a scientist who performs a workflow execution in such an environment can (1) document the data provenance for a data item created by the execution, and (2) use the provenance documentation as a recipe to re-execute the workflow. This thesis pro poses a provenance model for delivering data provenance support in a service-based environment. Through the use of an example scenario of a scientific workflow in the Astrophysics domain, we explore and identify components of the provenance model. The provenance model proposes a technique to collect and record data provenance for service-based workflow executions. The technique facilitates the collection of data provenance of workflow execution at runtime. In order to record the collected data provenance, the thesis also proposes a specification to represent provenance to de scribe the processing history whereby a piece of data was derived. The thesis also proposes query interfaces that allow recorded provenance to be queried, has formulated a technique to construct provenance graphs, and supports the re-execution of past workflows. The provenance representation specification, the collection technique, and the query interfaces have been used to implement a prototype system to demonstrate the proposed model. The thesis also experimentally evaluates the scalability of the components implemented

Consulting (in Writing) to the Corporation: Principles and Pragmatics

Provenance information provides a useful basis to verify whether a particular application behavior has been adhered to. This is particularly useful to evaluate the basis for a particular outcome, as a result of a process, and to verify if the process involved in making the decision conforms to some pre-defined set of rules. This is significant in a healthcare scenario, where it is necessary to demonstrate that patient data has been processed in a particular way. Understanding how provenance information may be recorded, stored, and subsequently analyzed by a decision maker is therefore significant in a service oriented architecture, which involves the use of third party services over which the decision maker does not have control. The aggregation of data from multiple sources of patient information plays an important part in subsequent treatments that are proposed for a patient. A tool to navigate through and analyze such provenance information is proposed, based on the use of a portal framework that allows different views on provenance information to co-exist. The portal enables users to add custom portlets enabling application specific views that would facilitate particular decision making

Trust Assessment Using Provenance in Service Oriented Applications

Workflow forms a key part of many existing Service Oriented applications, involving the integration of services that may be made available at distributed sites. It is possible to distinguish between an "abstract" workflow description outlining which services must be involved in a workflow execution and a "physical" workflow description outlining the particular instances of services that were used in a particular enactment. Provenance information provides a useful way to capture the physical workflow description automatically especially if this information is captured in a standard format. Subsequent analysis on this provenance information may be used to evaluate whether the abstract workflow description has been adhered to, and to enable a user executing a workflow-based application to establish "trust" in the outcome