Design and Evaluation of the Hamal Parallel Computer

Parallel shared-memory machines with hundreds or thousands of processor-memory nodes have been built; in the future we will see machines with millions or even billions of nodes. Associated with such large systems is a new set of design challenges. Many problems must be addressed by an architecture in order for it to be successful; of these, we focus on three in particular. First, a scalable memory system is required. Second, the network messaging protocol must be fault-tolerant. Third, the overheads of thread creation, thread management and synchronization must be extremely low. This thesis presents the complete system design for Hamal, a shared-memory architecture which addresses these concerns and is directly scalable to one million nodes. Virtual memory and distributed objects are implemented in a manner that requires neither inter-node synchronization nor the storage of globally coherent translations at each node. We develop a lightweight fault-tolerant messaging protocol that guarantees message delivery and idempotence across a discarding network. A number of hardware mechanisms provide efficient support for massive multithreading and fine-grained synchronization. Experiments are conducted in simulation, using a trace-driven network simulator to investigate the messaging protocol and a cycle-accurate simulator to evaluate the Hamal architecture. We determine implementation parameters for the messaging protocol which optimize performance. A discarding network is easier to design and can be clocked at a higher rate, and we find that with this protocol its performance can approach that of a non-discarding network. Our simulations of Hamal demonstrate the effectiveness of its thread management and synchronization primitives. In particular, we find register-based synchronization to be an extremely efficient mechanism which can be used to implement a software barrier with a latency of only 523 cycles on a 512 node machine.

Foundations of Actor Semantics

The actor message-passing model of concurrent computation has inspired new ideas in the areas of knowledge-based systems, programming languages and their semantics, and computer systems architecture. The model itself grew out of computer languages such as Planner, Smalltalk, and Simula, and out of the use of continuations to interpret imperative constructs within A-calculus. The mathematical content of the model has been developed by Carl Hewitt, Irene Greif, Henry Baker, and Giuseppe Attardi. This thesis extends and unifies their work through the following observations. The ordering laws postulated by Hewitt and Baker can be proved using a notion of global time. The most general ordering laws are in fact equivalent to an axiom of realizability in global time. Independence results suggest that some notion of global time is essential to any model of concurrent computation. Since nondeterministic concurrency is more fundamental than deterministic sequential computation, there may be no need to take fixed points in the underlying domain of a power domain. Power domains built from incomplete domains can solve the problem of providing a fixed point semantics for a class of nondeterministic programming languages in which a fair merge can be written. The event diagrams of Greif's behavioral semantics, augmented by Baker's pending events, form an incomplete domain. Its power domain is the semantic domain in which programs written in actor-based languages are assigned meanings. This denotational semantics is compatible with behavioral semantics. The locality laws postulated by Hewitt and Baker may be proved for the semantics of an actor-based language. Altering the semantics slightly can falsify the locality laws. The locality laws thus constrain what counts as an actor semantics.

Issues in the Design and Implementation of Act 2

Act2 is a highly concurrent programming language designed to exploit the processing power available from parallel computer architectures. The language supports advanced concepts in software engineering, providing high-level constructs suitable for implementing artificially-intelligent applications. Act2 is based on the Actor model of computation, consisting of virtual computational agents which communicate by message-passing. Act2 serves as a framework in which to integrate an actor language, a description and reasoning system, and a problem-solving and resource management system. This document describes issues in Act2's design and the implementation of an interpreter for the language.

Qualitative evaluation of KA24 (Knowledge Access 24)

Durbin, J. & Urquhart, C. (2003). Qualitative evaluation of KA24 (Knowledge Access 24). Aberystwyth: Department of Information Studies, University of Wales Aberystwyth. Sponsorship: Knowledge Access 24 (NHS)

JUSTEIS: JISC Usage Surveys: Trends in Electronic Information Services Final report 2003/2004 Cycle Five

Urquhart, C., Spink, S., Thomas, R., Yeoman, A., Durbin, J., Turner, J., Fenton, R. & Armstrong, C. (2004). JUSTEIS: JISC Usage Surveys: Trends in Electronic Information Services Final report 2003/2004 Cycle Five. Aberystwyth: Department of Information Studies, University of Wales Aberystwyth. Sponsorship: JISC

Rubisco small subunit, chlorophyll a/b-binding protein and sucrose : fructan-6-fructosyl transferase gene expression and sugar status in single barley leaf cells in situ. Cell type specificity and induction by light

Chungui Lu, Olga A. Koroleva, John F. Farrar, Joe Gallagher, Chris J. Pollock, and A. Deri Tomos (2002). Rubisco small subunit, chlorophyll a/b-binding protein and sucrose : fructan-6-fructosyl transferase gene expression and sugar status in single barley leaf cells in situ. Cell type specificity and induction by light. Plant Physiology, 130 (3) pp.1335-1348 Sponsorship: BBSRC RAE2008

Rozproszone algorytmy aproksymacyjne dla grafów dyskowych

Wydział Matematyki i Informatyki: Zakład Matematyki Dyskretnej

Radio i jego miejsce w życiu codziennym. Studium odbioru stacji radiowych w Polsce po 1989 roku. Analiza i interpretacja badań jakościowych

Wydział Historyczny: Instytut Etnologii i Antropologii Kulturowej

Edukacyjne implikacje technologii cyfrowych

W ciągu minionych trzech dekad świat radykalnie się zmienił. Jesteśmy świadkami transformacji od społeczeństwa przemysłowego do społeczeństwa informacyjnego. Jeśli chcielibyśmy określić tą zmianę jednym słowem byłoby nim: cyfryzacja. Początkiem było wynalezienie cyfrowego komputera, a później wszystkie stare analogowe formy medialne (tekst, dźwięk, obraz, film) reprezentowane poprzez ciągłe (analogowe) sygnały zostały zastąpione przez nowe postaci cyfrowe. Pojęcie cyfrowy oznacza, że dowolne informacje mogą być reprezentowana w formie ciągów liczb zapisanych w dwójkowym systemie liczbowym (jako ciąg znaków: 0 i 1). W artykule pokazujemy funkcjonalne ograniczenia mediów analogowych oraz rozważamy korzyści wynikające z cyfrowych reprezentacji różnych form informacji wskazując równocześnie zmiany jakie implikuje to dla procesu uczenia się i edukacji.

Komizm w teorii i praktyce antycznej powieści greckiej

The topic of the study entitled humour in the ancient greek novels: the theoretical conceptions and the lite- rary practice is significance of humour in ancient Greek novels. In the first part of this study the theoretical aspects are examined with reference to the conceptions of contemporary researchers of Greek novels. The influence of the humour on the character of the world presented in particular novels is considered in the second part of the article.

La idiosincrasia del lenguaje almodovariano y su repercusión sobre la traducción. Analisis de algunas de las soluciones en el campo de la variación lingüística del subtitulado en polaco de “Volver” (2006)

The identification of an original and idiosyncratic style in the work of the Spanish filmmaker Pedro Almodóvar provides the tone of the speech with a semantic function: linguistic variation and specific registers help to transmit the message and intention of the author. As a consequence of this, the possibilities for the translation being carried away in similar linguistic terms to those of the original text will be higher than in texts without linguistic peculiarities or stylistically unmarked. The purpose of this paper is to reflect on the influence exerted by the original author in the reception of his work abroad and, consequently, in its translation. In this sense, we will analyse the informative value of certain linguistic uses as well as the importance of enriching stylistically the subtitles in these connotative texts through the example of Almodóvar’s film "Volver" and its translation into Polish (2006).

Prezbiter - świadek i sługa komunii. Aktualność przesłania Listu do moich kapłanów

Inspiracją dla autora artykułu stały się zebrane w Liście do moich kapłanów refleksje Prymasa Wyszyńskiego na temat tożsamości i misji prezbitera. Zawierają one wiele wątków, które niewątpliwie łączy przenikająca całe dzieło troska o jedność kapłanów w służbie eklezjalnej komunii. Dla Prymasa Tysiąclecia społeczna natura człowieka była czytelnym potwierdzeniem prawdy o jego powołaniu do życia we wspólnocie, nie tylko tej doczesnej, ale i tej nadprzyrodzonej. Należało tę naturalną zdolność do wchodzenia w relacje z innymi właściwie odczytać w świetle Bożego Objawienia. Bogate życie wewnętrzne pozwala kontemplować tajemnicę Trójcy Świętej i dostrzegać w Niej źródło eklezjalnej i międzyludzkiej komunii. Obdarowanie nadprzyrodzoną mocą wspólnoty z Bogiem w Kościele, uzdalnia wierzących w Chrystusa do nowych braterskich relacji, czyniąc z nich prawdziwą Bożą rodzinę. Proces ten dokonuje się dzięki pośrednictwu posługi kapłańskiej, dlatego też prezbiterzy są szczególnie wezwani, aby w ich wzajemnych relacjach jaśniał ten nowy, wspólnotowy styl życia. Osobista więź z Bogiem, relacja z ordynariuszem, pomiędzy prezbiterami, czy też z wiernymi świeckimi to podstawowe wymiary, w których kapłani mają jawić się jako świadkowie i słudzy komunii.

Filozofia antyczna wobec problemu interpretacji. Rozwój alegorezy od przedsokratyków do Arystotelesa

The present work examines the beginnings of ancient hermeneutics. More specifically, it discusses the connection between the rise of the practice of allegoresis, on the one hand, and the emergence of the first theory of figurative language, on the other. Thus, this book investigates the specific historical and cultural circumstances that enabled the ancient Greeks not only to discover the possibility of allegorical interpretation, but also to treat figurative language as a philosophical problem. By posing difficulties in understanding the enigmatic sense of various esoteric doctrines, poems, oracles and riddles, figurative language created the context for theoretical reflection on the meaning of these “messages”. Hence, ancient interpreters began to ponder over the nature and functions of figurative (“enigmatic”) language as well as over the techniques of its proper use and interpretation. Although the practice of allegorical interpretation was closely linked to the development of the whole of ancient philosophy, the present work covers only the period from the 6th to the 4th century B.C. It concentrates, then, on the philosophical and cultural consequences of allegoresis in the classical age. The main thesis advocated here has it that the ancient Greeks were in-clined to regard allegory as a cognitive problem rather than merely as a stylistic or a literary one. When searching for the hidden meanings of various esoteric doc-trines, poems, oracles and riddles, ancient interpreters of these “messages” assumed allegory to be the only tool suitable for articulating certain matters. In other words, it was their belief that the use of figurative language resulted from the necessity of expressing things that were otherwise inexpressible. The present work has been organized in the following manner. The first part contains historical and philological discussions that provide the point of departure for more philosophical considerations. This part consists of two introductory chapters. Chapter one situates the practice of allegorical interpretation at the borderline of two different traditions: the rhetorical-grammatical and the hermeneutical. In order to clearly differentiate between the two, chapter one distinguishes between allegory and allegoresis, on the one hand, and allegoresis and exegesis, on the other. While pointing to the conventionality (and even arbitrariness) of such distinctions, the chapter argues, nevertheless, for their heuristic usefulness. The remaining part of chapter one focuses on a historical and philological reconstruction of the most important conceptual tools of ancient hermeneutics. Discussing the semantics of such terms as allēgoría, hypónoia, ainigma and symbolon proves important for at least two crucial reasons. Firstly, it reveals the mutual affinity between allegoresis and divination, i.e., practices that are inherently connected with the need to discover the latent meaning of the “message” in question (whether poem or oracle). Secondly, these philological analyses bring to light the specificity of the ancient understanding of such concepts as allegory or symbol. It goes without saying that antiquity employed these terms in a manner quite disparate from modernity. Chapter one concludes with a discussion of ancient views on the cognitive value of figurative (“enigmatic”) language. Chapter two focuses on the role that allegoresis played in the process of transforming mythos into logos. It is suggested here that it was the practice of allegorical interpretation that made it possible to preserve the traditional myths as an important point of reference for the whole of ancient philosophy. Thus, chapter two argues that the existence of a clear opposition between mythos into logos in Preplatonic philosophy is highly questionable in light of the indisputable fact that the Presocratics, Sophists and Cynics were profoundly convinced about the cognitive value of mythos (this conviction was also shared by Plato and Aristotle, but their attitude towards myth was more complex). Consequently, chapter two argues that in Preplatonic philosophy, myth played a function analogous to the concepts discussed in chapter one (i.e., hidden meanings, enigmas and symbols), for in all these cases, ancient interpreters found tools for conveying issues that were otherwise difficult to convey. Chapter two concludes with a classification of various types of allegoresis. Whilst chapters one and two serve as a historical and philological introduction, the second part of this book concentrates on the close relationship between the development of allegoresis, on the one hand, and the flowering of philosophy, on the other. Thus, chapter three discusses the crucial role that allegorical interpretation came to play in Preplatonic philosophy, chapter four deals with Plato’s highly complex and ambivalent attitude to allegoresis, and chapter five has been devoted to Aristotle’s original approach to the practice of allegorical interpretation. It is evident that allegoresis was of paramount importance for the ancient thinkers, irrespective of whether they would value it positively (Preplatonic philosophers and Aristotle) or negatively (Plato). Beginning with the 6th century B.C., the ancient practice of allegorical interpretation is motivated by two distinct interests. On the one hand, the practice of allegorical interpretation reflects the more or less “conservative” attachment to the authority of the poet (whether Homer, Hesiod or Orpheus). The purpose of this apologetic allegoresis is to exonerate poetry from the charges leveled at it by the first philosophers and, though to a lesser degree, historians. Generally, these allegorists seek to save the traditional paideia that builds on the works of the poets. On the other hand, the practice of allegorical interpretation reflects also the more or less “progressive” desire to make original use of the authority of the poet (whether Homer, Hesiod or Orpheus) so as to promote a given philosophical doctrine. The objective of this instrumental allegoresis is to exculpate philosophy from the accusations brought against it by the more conservative circles. Needless to say, these allegorists significantly contribute to the process of the gradual replacing of the mythical view of the world with its more philosophical explanation. The present book suggests that it is the philosophy of Aristotle that should be regarded as a sort of acme in the development of ancient hermeneutics. The reasons for this are twofold. On the one hand, the Stagirite positively values the practice of allegoresis, rehabilitating, thus, the tradition of Preplatonic philosophy against Plato. And, on the other hand, Aristotle initiates the theoretical reflection on figurative (“enigmatic”) language. Hence, in Aristotle we encounter not only the practice of allegoresis, but also the theory of allegory (although the philosopher does not use the term allēgoría). With the situation being as it is, the significance of Aristotle’s work cannot be overestimated. First of all, the Stagirite introduces the concept of metaphor into the then philosophical considerations. From that moment onwards, the phenomenon of figurative language becomes an important philosophical issue. After Aristo-tle, the preponderance of thinkers would feel obliged to specify the rules for the appropriate use of figurative language and the techniques of its correct interpretation. Furthermore, Aristotle ascribes to metaphor (and to various other “excellent” sayings) the function of increasing and enhancing our knowledge. Thus, according to the Stagirite, figurative language is not only an ornamental device, but it can also have a significant explanatory power. Finally, Aristotle observes that figurative expressions cause words to become ambiguous. In this context, the philosopher notices that ambiguity can enrich the language of a poet, but it can also hinder a dialectical discussion. Accordingly, Aristotle is inclined to value polysemy either positively or negatively. Importantly, however, the Stagirite is perfectly aware of the fact that in natural languages ambiguity is unavoidable. This is why Aristotle initiates a syste-matic reflection on the phenomenon of ambiguity and distinguishes its various kinds. In Aristotle, ambiguity is, then, both a problem that needs to be identified and a tool that can help in elucidating intricate philosophical issues. This unique approach to ambiguity and figurative (“enigmatic”) language enabled Aristotle to formulate invaluable intuitions that still await appropriate recognition.

Idiom processing in aphasic patients

The aim of the present paper is to provide insight into the issue of idiom comprehension in pa- tients who are in the process of recovery from the syndrome of aphasia. Research in figurative language comprehension has seen a robust development in the recent decades. However, it has not been until quite recently that psycholinguists began to delve into the aspect of metaphorical language comprehension in brain damaged populations. It was observed that even though the ability to produce and understand language is recovered in the majority of patients with head trauma, the impairment of some aspects of comprehension may protract. The understanding of idioms, metaphors, similes and proverbs, due to their specific, non-literal character, has been evi- denced to pose a serious problem to aphasic patients, as they fail to decipher the figurative mean- ing of the utterance, and, instead, tend to process the message literally (Papagno et al. 2004). In the present study, three patients who suffered from aphasic disorder were tested for com- prehension of idioms by means of two multiple choice tasks. The obtained results corroborated the hypothesis that patients who are in the process of recovery from aphasia encounter various pitfalls in the comprehension of idiomatic language. Predominantly, they exhibit an inclination to choose the erroneous, literal paraphrases of the presented idioms over their correct, idiomatic counterparts. The present paper aims at accounting for the reasons underlying such a tendency.

Fasciathérapie et transformation du rapport à la santé

Dissertação de Mestrado apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Psicopedagogia Perceptiva.