Browsing by Author "Simmonds, Robert"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Open Access
    Assessing GridSim for modeling the global distribution of next-generation astronomy data
    (2025) Tunbridge, James K; Simmonds, Robert
    The transfer of big data between geographic locations incurs various costs that are better managed when computing resources are used efficiently. Measuring the energy used by a computing facility is a mechanism for managing computational efficiency because the energy provided to the facility can be measured and managed. The Square Kilometer Array (SKA) radio telescope will share large volumes of science-ready astronomical data with the project collaborating partners. This dissertation attempts to address the weaknesses of the GridSim simulation toolkit for the configuration of the SKA data grid. Some of the GridSim features suited for the simulation project are: a) a network extension claiming realistic network communication; b) an extendable application programming interface because of the Java programming language; c) a datagrid extension that simulates distributed data storage, and tasks for managing the distributed files; d) packet- and flow-level network extensions and e) GridSim is used in simulations of similar real-world networks e.g., the Australian GrangeNet Gigabit network. GridSim was built primarily for modeling resources and application scheduling of parallel computing and distributed computation grids, and to assess different job scheduling policies. The SKA wide area collaborative network will send data to its distributed partners who have their own network and energy-related policies. This work proposes a design to implement, in GridSim, a prototype of the end-to-end energy cost model for large scale networks, ECOFEN (Orgerie, 2015). The purpose of this work being to demonstrate the utility of the GridSim toolkit in spite of a few known problems with the software. Invalidation exercises were performed to determine the cause of lost events in a network extension simulation, and to assess the implementation of the Routing Information Protocol, in GridSim, in multiple executions of the same simulation and configuration. In this work, GridSim simulations lose events for which a solution is suggested. In addition, the work found that routing tables do not always contain matching shortest path information for multiple executions of a simulation. The implementation of the proposed design for an ECOFEN model extension in GridSim is a project for future work after one unsuccessful attempt to implement the model in GridSim. This work considered other simulation tools as potential alternatives to the GridSim toolkit, finding SimGrid to be a likely candidate. Modern computational systems are just too complex for popular software simulation tools to copy dependably which has supported a return to live network emulation testbeds for the accurate and scalable modeling of real-world systems.
  • No Thumbnail Available
    Item
    Open Access
    South African Astronomical Observatory data archiving for multi-wavelength astronomy research
    (2023) Botha, Lucian; Simmonds, Robert
    This research investigates the best practices for creating a data archive system that can store optical and radio astronomy data as well as interact with other astronomy archives. Archives are built and maintained by staff that specialise in big data storage, information security, database administration, and general information technology that provide platforms for access to research data to the broader astronomy community. The tools and services provided by the IVOA allow data to be located, compared, and retrieved, combining multispectral and multiple instrument data from different archives to show the evolution of data interoperability across wavelengths. The diverse methods applied and the organisation of resources and collaboration between different facilities to reach common goals will broaden the scope and availability of data throughout the research community. Using data from various archives makes multi-wavelength investigations a significant topic in astronomy. Astronomy data archives employ a variety of authentication mechanisms, including Open Authorization (OAuth), Security Assertion Markup Language (SAML), Central Authentication Service (CAS), and traditional web-based authentication with usernames and passwords. Challenges faced by archives include the increased complexity of data which can be addressed by choosing the appropriate level of standardisation. As astronomy and data science are rapidly evolving, it is a challenge to keep up with all of the new developments, so there needs to be a strategy of research and development so that new technologies and techniques can be adopted.
  • No Thumbnail Available
    Item
    Open Access
    VRDAV is: remote visualisation of astronomy data with a standalone virtual reality device
    (2025) Van Zyl, Michaela; Simmonds, Robert; Comrie, Angus
    This dissertation explores the challenges of visualising vast astronomy data cubes using a virtual reality environment, addressing the ever-increasing volume of data collected by radio astronomy instruments. As the amount of data grows year after year—ranging from terabytes to petabytes—radio astronomy researchers face significant difficulties in processing, storing, and analysing this immense data. The visual analysis of the collected data is a crucial part of radio astronomy research. Traditional visualisation tools are often inadequate due to the size and complexity of the data. The Data far exceeds the computational capabilities of devices like laptops or home desktop computers. Researchers are often required to either access specialised systems or analyse small portions of the data at a time. Specialised systems are typically locked to specific locations and inaccessible to many, and segmenting the data can obscure the broader context of a dataset. These points highlight the need for a new approach to overcome the presented limitations. The objective of this research is to develop a prototype system that enables the visualization of large astronomy data cubes in a virtual reality environment using a standalone VR headset. The system is specifically designed to operate on devices with limited computational power, such as laptops and VR headsets. Making it accessible to a wider range of users. The research addresses key questions, including the feasibility of remote implementation, the scalability of the system for handling large datasets, and a performance comparison with existing astronomy visualisation systems. The VRDAVis system design follows a client-server architecture, where the client-side communicates with the server to visualise large astronomy data cubes. These client devices are either a computer or standalone VR headset. The system pre-processes the data into multiple resolution levels, these levels are referred to as mipmaps, to reduce the computational load on the client. The front-end, built as a web-based application, allows users to select data cubes and progressively visualise different levels of detail. The resolution levels start from a low-resolution overview to higher resolution as a user zooms in on areas of interest. The client and server communicate via WebSock-ets, and WebRTC is used for peer-to-peer connections when transferring the application's state between devices (e.g., from desktop to VR). The VRDAVis system was tested through an qualitative study, with participants who were astronomy researchers familiar with VR technology. The participants were asked to perform various actions using VRDAVis. The tasks involved selecting a file on the laptop, transferring the session to the VR head-set, and interacting with the data cube. Key findings were gathered from user feedback, focusing on their experience with the system's usability, interaction with the visualizations, and the overall workflow. Observations on task performance and any difficulties encountered were also collected, along with participants' impressions of working in the VR environment.