A formal semantics for control and data flow in the gannet service-based system-on-chip architecture

There is a growing demand for solutions which allow the design of large and complex reconfigurable Systems-on- Chip (SoC) at high abstraction levels. The Gannet project proposes a functional programming approach for high-abstraction design of very large SoCs. Gannet is a distributed service-based SoC architecture, i.e. a network of services offered by hardware or software cores. The Gannet SoC is task-level reconfigurable: it performs tasks by executing functional task description programs using a demand-driven dataflow mechanism. The Gannet architecture combines the flexible connectivity offered by a Networkon- Chip with the functional language paradigm to create a fully concurrent distributed SoC with the option to completely separate data flows from control flows. This feature is essential to avoid a bottleneck at he controller for run-time control of multiple high-throughput data flows. In this paper we present the Gannet architecture and language and introduce an operational semantics to formally describe the mechanism to separate control and data flows

GPRM: a high performance programming framework for manycore processors

Processors with large numbers of cores are becoming commonplace. In order to utilise the available resources in such systems, the programming paradigm has to move towards increased parallelism. However, increased parallelism does not necessarily lead to better performance. Parallel programming models have to provide not only flexible ways of defining parallel tasks, but also efficient methods to manage the created tasks. Moreover, in a general-purpose system, applications residing in the system compete for the shared resources. Thread and task scheduling in such a multiprogrammed multithreaded environment is a significant challenge. In this thesis, we introduce a new task-based parallel reduction model, called the Glasgow Parallel Reduction Machine (GPRM). Our main objective is to provide high performance while maintaining ease of programming. GPRM supports native parallelism; it provides a modular way of expressing parallel tasks and the communication patterns between them. Compiling a GPRM program results in an Intermediate Representation (IR) containing useful information about tasks, their dependencies, as well as the initial mapping information. This compile-time information helps reduce the overhead of runtime task scheduling and is key to high performance. Generally speaking, the granularity and the number of tasks are major factors in achieving high performance. These factors are even more important in the case of GPRM, as it is highly dependent on tasks, rather than threads. We use three basic benchmarks to provide a detailed comparison of GPRM with Intel OpenMP, Cilk Plus, and Threading Building Blocks (TBB) on the Intel Xeon Phi, and with GNU OpenMP on the Tilera TILEPro64. GPRM shows superior performance in almost all cases, only by controlling the number of tasks. GPRM also provides a low-overhead mechanism, called “Global Sharing”, which improves performance in multiprogramming situations. We use OpenMP, as the most popular model for shared-memory parallel programming as the main GPRM competitor for solving three well-known problems on both platforms: LU factorisation of Sparse Matrices, Image Convolution, and Linked List Processing. We focus on proposing solutions that best fit into the GPRM’s model of execution. GPRM outperforms OpenMP in all cases on the TILEPro64. On the Xeon Phi, our solution for the LU Factorisation results in notable performance improvement for sparse matrices with large numbers of small blocks. We investigate the overhead of GPRM’s task creation and distribution for very short computations using the Image Convolution benchmark. We show that this overhead can be mitigated by combining smaller tasks into larger ones. As a result, GPRM can outperform OpenMP for convolving large 2D matrices on the Xeon Phi. Finally, we demonstrate that our parallel worksharing construct provides an efficient solution for Linked List processing and performs better than OpenMP implementations on the Xeon Phi. The results are very promising, as they verify that our parallel programming framework for manycore processors is flexible and scalable, and can provide high performance without sacrificing productivity

Plant figurations : a vital study in rhetorical address following Theodor W. Adorno

In this dissertation, I ask the question: how is (and is not) the plant both subject and object of human rhetoric? In taking up the question, I explore an array of texts, artifacts, and encounters revealing “the plant” addressed as a vital object of subjective experience and as a subject of objective reflection. Following what Diane Davis and Michelle Ballif call “extrahuman rhetorical relations,” I demonstrate an orientation of struggle that holds the question open at its limit, by approaching iterations of “the plant” caught in motion. I apply a method drawn from Frankfurt School scholar Theodor W. Adorno’s invitation to apply negative dialectics—or immanent criticism—to everyday sites of personal encounter and interdisciplinary texts. I understand the dialectic features of human-plant relations in three chapters or figures studies. First, I examine the concept of “natural history” revealed in a site-specific experience at Red Rock State Park in California. Second, I look at the historic and contemporary texts that name a parasitic liana known as the Sipo-Matador. Third, I hear the sounding of European trees emanating through a vinyl copy of the 2012 art-album Years by Bartholomäus Traubeck. Approaching these figures in affirmative and negative modes, I argue that keeping the dialectic in motion instantiates a critical process—a reflection on reflective capacity—across multiple renderings of representation and structure. Writing and reading is an essential part of this process. In understanding thinking as a movement of mediation—a dramatic journey joining the dialectic across theoretical abstraction and lived reality—I reveal a multidimensional orientation to rhetorical criticism suited to hear the plant, addressed. My approach, I argue, keeps Adorno and the plant—both subjects and objects of this dissertation—close enough to touch while at bay enough to remain mysterious. I trace a malignant structure surrounding my encounter between the human and the plant—the Enlightenment in its dominating iterations—in relief as much as I hope to leave open creative reflection and vital critique.Communication Studie

Physical, biological and cultural factors influencing the formation, stabilisation and protection of archaeological deposits in U.K. coastal waters

A considerable corpus of information regarding the formation of terrestrial archaeological deposits exists which is not matched by studies of deposit formation in coastal waters. Similarly, there is a disjunction between strident calls for minimal disturbance investigation, with conservation in situ, and knowledge of how this might actually be achieved in the marine environment. The manner in which the investigation of deposit formation can complement the study of in situ conservation is considered An approach is proposed which combines selected elements of Schiffer's Transformation Theory with a method of studying changes to deposits outlined by Wildesen. It is suggested that, although sufficient regularities can be detected in the influence of formation processes to allow their influence to be recognised and inference refined accordingly, there are case specific limitations on the extent to which the precise influence of each process can be described and evaluated. A case study is presented which investigates casual depredation as a formation process. Commercial fishing activity and marine burrowing activity are the subject of detailed consideration. New insights into these processes result from this study and specific recommendations concerning in situ conservation of deposits subject to their influence are made. The need to consider fishing practice as well as the mechanical properties of fishing gear in the study of deposit formation and protection is emphasised. The excavation of a 16th century wreck in Studland Bay, Dorset, is used to demonstrate the pervasive influence of burrowing activity and the problems associated with mitigation of this process. Recommendations are made regarding future study of formation processes and the development of policy related to the management of the submerged archaeological resource