High level synthesis of RDF queries for graph analytics

In this paper we present a set of techniques that enable the synthesis of efficient custom accelerators for memory intensive, irregular applications. To address the challenges of irregular applications (large memory footprint, unpredictable fine-grained data accesses, and high synchronization intensity), and exploit their opportunities (thread level parallelism, memory level parallelism), we propose a novel accelerator design that employs an adaptive and Distributed Controller (DC) architecture, and a Memory Interface Controller (MIC) that supports concurrent and atomic memory operations on a multi-ported/multi-banked shared memory. Among the multitude of algorithms that may benefit from our solution, we focus on the acceleration of graph analytics applications and, in particular, on the synthesis of SPARQL queries on Resource Description Framework (RDF) databases. We achieve this objective by incorporating the synthesis techniques into Bambu, an Open Source high-level synthesis tools, and interfacing it with GEMS, the Graph database Engine for Multithreaded Systems. The GEMS' front-end generates optimized C implementations of the input queries, modeled as graph pattern matching algorithms, which are then automatically synthesized by Bambu. We validate our approach by synthesizing several SPARQL queries from the Lehigh University Benchmark (LUBM)

Automatic Application-Specific Customization of Softcore Processor Microarchitecture, Masters Thesis, May 2006

Applications for constrained embedded systems are subject to strict runtime and resource utilization bounds. With soft core processors, application developers can customize the processor for their application, constrained by available hardware resources but aimed at high application performance. The more reconfigurable the processor is, the more options the application developers will have for customization and hence increased potential for improving application performance. However, such customization entails developing in-depth familiarity with all the parameters, in order to configure them effectively. This is typically infeasible, given the tight time-to-market pressure on the developers. Alternatively, developers could explore all possible configurations, but being exponential, this is infeasible even given only tens of parameters. This thesis presents an approach based on an assumption of parameter independence, for automatic microarchitecture customization. This approach is linear with the number of parameter values and hence, feasible and scalable. For the dimensions that we customize, namely application runtime and hardware resources, we formulate their costs as a constrained binary integer nonlinear optimization program. Though the results are not guaranteed to be optimal, we find they are near-optimal in practice. Our technique itself is general and can be applied to other design-space exploration problems

Coordinating Aerial Robots and Unattended Ground Sensors for Intelligent Surveillance Systems

Sensor networks are being used to implement different types of sophisticated emerging applications, such as those aimed at supporting ambient intelligence and surveillance systems. This usage is enhanced by employing sensors with different characteristics in terms of sensing, computing and mobility capabilities, working cooperatively in the network. However, the design and deployment of these heterogeneous systems present several issues that have to be handled in order to meet the user expectations. The main problems are related to the nodes‘ interoperability and the overall resource allocation, both inter and intra nodes. The first problem requires a common platform that abstracts the nodes’ heterogeneity and provides a smooth communication, while the second is handled by cooperation mechanisms supported by the platform. Moreover, as the nodes are supposed to be heterogeneous, a customizable platform is required to support both resource rich and poorer nodes. This paper analyses surveillance systems based on a heterogeneous sensor network, which is composed by lowend ground sensor nodes and autonomous aerial robots, i.e. Unmanned Aerial Vehicles (UAVs), carrying different kinds of sensors. The approach proposed in this work tackles the two above mentioned problems by using a customizable hardware platform and a middleware to support interoperability. Experimental results are also provided

Digital Fabrication Approaches for the Design and Development of Shape-Changing Displays

Interactive shape-changing displays enable dynamic representations of data and information through physically reconfigurable geometry. The actuated physical deformations of these displays can be utilised in a wide range of new application areas, such as dynamic landscape and topographical modelling, architectural design, physical telepresence and object manipulation. Traditionally, shape-changing displays have a high development cost in mechanical complexity, technical skills and time/finances required for fabrication. There is still a limited number of robust shape-changing displays that go beyond one-off prototypes. Specifically, there is limited focus on low-cost/accessible design and development approaches involving digital fabrication (e.g. 3D printing). To address this challenge, this thesis presents accessible digital fabrication approaches that support the development of shape-changing displays with a range of application examples – such as physical terrain modelling and interior design artefacts. Both laser cutting and 3D printing methods have been explored to ensure generalisability and accessibility for a range of potential users. The first design-led content generation explorations show that novice users, from the general public, can successfully design and present their own application ideas using the physical animation features of the display. By engaging with domain experts in designing shape-changing content to represent data specific to their work domains the thesis was able to demonstrate the utility of shape-changing displays beyond novel systems and describe practical use-case scenarios and applications through rapid prototyping methods. This thesis then demonstrates new ways of designing and building shape-changing displays that goes beyond current implementation examples available (e.g. pin arrays and continuous surface shape-changing displays). To achieve this, the thesis demonstrates how laser cutting and 3D printing can be utilised to rapidly fabricate deformable surfaces for shape-changing displays with embedded electronics. This thesis is concluded with a discussion of research implications and future direction for this work

Survey and Analysis of Production Distributed Computing Infrastructures

This report has two objectives. First, we describe a set of the production distributed infrastructures currently available, so that the reader has a basic understanding of them. This includes explaining why each infrastructure was created and made available and how it has succeeded and failed. The set is not complete, but we believe it is representative. Second, we describe the infrastructures in terms of their use, which is a combination of how they were designed to be used and how users have found ways to use them. Applications are often designed and created with specific infrastructures in mind, with both an appreciation of the existing capabilities provided by those infrastructures and an anticipation of their future capabilities. Here, the infrastructures we discuss were often designed and created with specific applications in mind, or at least specific types of applications. The reader should understand how the interplay between the infrastructure providers and the users leads to such usages, which we call usage modalities. These usage modalities are really abstractions that exist between the infrastructures and the applications; they influence the infrastructures by representing the applications, and they influence the ap- plications by representing the infrastructures