Beltway: Getting Around Garbage Collection Gridlock

We present the design and implementation of a new garbage collection framework that significantly generalizes existing copying collectors. The Beltway framework exploits and separates object age and incrementality. It groups objects in one or more increments on queues called belts, collects belts independently, and collects increments on a belt in first-in-first-out order. We show that Beltway configurations, selected by command line options, act and perform the same as semi-space, generational, and older-first collectors, and encompass all previous copying collectors of which we are aware. The increasing reliance on garbage collected languages such as Java requires that the collector perform well. We show that the generality of Beltway enables us to design and implement new collectors that are robust to variations in heap size and improve total execution time over the best generational copying collectors of which we are aware by up to 40%, and on average by 5 to 10%, for small to moderate heap sizes. New garbage collection algorithms are rare, and yet we define not just one, but a new family of collectors that subsumes previous work. This generality enables us to explore a larger design space and build better collectors

Competition Between Auctions

Even though auctions are capturing an increasing share of commerce, they are typically treated in the theoretical economics literature as isolated. That is, an auction is typically treated as a single seller facing multiple buyers or as a single buyer facing multiple sellers. In this paper, we review the state of the art of competition between auctions. We consider three different types of competition: competition between auctions, competition between formats, and competition between auctioneers vying for auction traffic. We highlight the newest experimental, statistical and analytical methods in the analysis of competition between auctions.auctions, bidding, competition, auction formats, auction houses

The Letter and the Spirit: A Unified Theory of Originalism

The concept of constitutional construction is of central importance to originalist theory but is both underdeveloped and controversial among originalists. Some object that its apparent open-endedness undermines the constraining virtues of originalism and exposes citizens to arbitrary judicial power. In this Article, we respond to this challenge by presenting an originalist theory of constitutional construction that can guide and constrain judicial activity within the “construction zone.” When combined with an originalist theory of constitutional interpretation, our approach yields a unified theory of originalism. Our theory of constitutional construction draws upon a familiar common-law concept long used in contract and fiduciary law to handle the problem of opportunistic abuse of discretion: the duty of good faith. We contend that judges who take an oath to “support this Constitution” enter into a fiduciary relationship with private citizens—a relationship characterized by discretionary powers in the hands of judges and a corresponding vulnerability in the citizenry. As fiduciaries, judges are morally and legally bound to follow the instructions given to them in “this Constitution” in good faith. This means that judges engaging in constitutional construction (or “implementation”) must seek to give legal effect to both the Constitution’s “letter” (its original public meaning) and its “spirit” (the original function or purpose of the particular clauses and general structure of the text). Therefore, when interpretation of original meaning is not sufficient to resolve a controversy, judges have a duty to employ good-faith construction. Good-faith construction consists of (a) accurately identifying the spirit—or “original function”—of the relevant constitutional provision at the time it was enacted and (b) devising implementing rules that are calculated to give effect to both the letter and the spirit of the text in the case at hand and in future cases. Conversely, bad-faith construction consists in opportunistically using the discretion inherent in implementing the Constitution to evade its original letter or spirit in pursuit of the judge’s own extraconstitutional preferences

Subheap-Augmented Garbage Collection

Automated memory management avoids the tedium and danger of manual techniques. However, as no programmer input is required, no widely available interface exists to permit principled control over sometimes unacceptable performance costs. This dissertation explores the idea that performance-oriented languages should give programmers greater control over where and when the garbage collector (GC) expends effort. We describe an interface and implementation to expose heap partitioning and collection decisions without compromising type safety. We show that our interface allows the programmer to encode a form of reference counting using Hayes\u27 notion of key objects. Preliminary experimental data suggests that our proposed mechanism can avoid high overheads suffered by tracing collectors in some scenarios, especially with tight heaps. However, for other applications, the costs of applying subheaps---in human effort and runtime overheads---remain daunting

Cognitivism and Innovation in Economics - Two Lectures

This issue of the Department W.P. reproduces two lectures by Professor Loasby organized by the CISEPS (Centre for Interdisciplinary Studies in Economics, Psychology and the Social Sciences at Bicocca) in collaboration with the IEP, the Istituto di Economia Politica of the Bocconi University in Milan. The first lecture was delivered at the University of Milano-Bicocca on 13 October 2003 and the second was staged the day after at the Bocconi University. The lectures are reproduced here together with a comment by dr. Stefano Brusoni of Bocconi and SPRU. Two further comments were presented at the time by Professor Richard Arena of the University of Nice and by Professor Pier Luigi Sacco of the University of Venice. Both of them deserve gratitude for active participation to the initiative. Unfortunately it has not been possible to include their comments in the printed form. In these lectures Brian Loasby opens under the title of Psychology of Wealth (a title echoing a famous essay by Carlo Cattaneo) and he develops an argument in cognitive economics which is based on Hayek’s theory of the human mind with significant complements and extensions, mainly from Smith and Marshall. The second lecture provides a discussion on organization and the human mind. It can be read independently although it is linked to the former. Indeed, in Professor Loasby’s words, “the psychology of wealth leads to a particular perspective on this problem of organization”. The gist of the argument lies in the need to appreciate the significance of an appropriate “balance between apparently conflicting principles: the coherence, and therefore the effectiveness, of this differentiated system requires some degree of compatibility between its elements, but the creation of differentiated knowledge and skills depends on the freedom to make idiosyncratic patterns by thinking and acting in ways which may be radically different from those of many other people”. This dilemma of compatibility vs. independence can find solution in a variety of contexts, as Loasby’s analysis shows. In his comments Richard Arena had focussed on the rationality issues, so prominent in Loasby’s text. For example, he had suggested that the cleavage between rational choice equilibrium and evolutionary order offers ground to new forms of self-organization. Pier Luigi Sacco had emphasized that Loasby’s approach breaks new ground on the economics of culture and paves the way to less simplistic conceptions of endogenous growth than is suggested by the conventional wisdom of current models. Unfortunately, as hinted above, is has proved impossible to include those comments in the present booklet along with Loasby’s lectures. A special obligation must be recorded to Dr. Stefano Brusoni, who has prepared a written version of his own comment which has been printed in this booklet and can be offered to the reader. Among other participants Roberto Scazzieri, of the University of Bologna, Tiziano Raffaelli, of the University of Pisa, Luigino Bruni of Bicocca, Riccardo Cappellin of Rome ‘Tor Vergata’ and others were able to offer significant comments during the two sessions of the initiative. The organizers are particularly grateful to Professor Brian Loasby for the active and generous support of the initiative. Together with our colleagues and students we have been able to admire his enthusiasm and intellectual creativity in treating some of the more fascinating topics of contemporary economics.

Biodiversity and Biocollections: Problem of Correspondence

This text is an English translation of those several sections of the original paper in Russian, where collection-related issues are considered. The full citation of the original paper is as following: Pavlinov I.Ya. 2016. [Bioraznoobrazie i biokollektsii: problema sootvetstvia]. In: Pavlinov I.Ya. (comp.). Aspects of Biodiversity. Archives of Zoological Museum of Lomonosov Moscow State University, Vol. 54, Pр. 733–786. Orientation of biology, as a natural science, on the study and explanation of the similarities and differences between organisms led in the second half of the 20th century to the recognition of a specifi c subject area of biological explorations, viz. biodiversity (BD). One of the important general scientifi c prerequisites for this shift was understanding that (at the level of ontology) the structured diversity of the living nature is its fundamental property equivocal to subjecting of some of its manifestations to certain laws. At the level of epistemology, this led to acknowledging that the “diversifi cationary” approach to description of the living beings is as justifi able as the before dominated “unifi cationary” one. This general trend has led to a signifi cant increase in the attention to BD. From a pragmatic perspective, its leitmotif was conservation of BD as a renewable resource, while from a scientifi c perspective the leitmotif was studying it was studying BD as a specifi c natural phenomenon. These two points of view are united by recognition of the need for scientific substantiation of BD conservation strategy, which implies the need for a detailed study of BD itself. At the level of ontology, one of the key problems in the study of BD (leaving aside the question of its genesis) is determination of its structure, which is interpreted as a manifestation of the structure of the Earth’s biota itself. With this, it is acknowledged that the subject area of empirical explorations is not the BD as a whole ( “Umgebung”) but its particular manifestations (“Umwelts”). It is proposed herewith to recognized, within the latter: fragments of BD (especially taxa and ecosystems), hierarchical levels of BD (primarily within- and interorganismal ones), and aspects of BD (before all taxonomic and meronomic ones). Attention is drawn to a new interpretation of bioinformatics as a discipline that studies the information support of BD explorations. An important fraction of this support are biocollections. The scientifi c value of collections means that they make it possible both empirical inferring and testing (verification) of the knowledge about BD. This makes biocollections, in their epistemological status, equivalent to experiments, and so makes studies of BD quite scientific. It is emphasized that the natural objects (naturalia), which are permanently kept in collections, contain primary (objective) information about BD, while information retrieved somehow from them is a secondary (subjective) one. Collection, as an information resource, serves as a research sample in the studies of BD. Collection pool, as the totality of all collection materials kept in repositories according to certain standards, can be treated as a general sample, and every single collection as a local sample. The main characteristic of collection-as-sample is its representativeness; so the basic strategy of development of the collection pool is to maximize its representativeness as a means to ensure correspondence of structure of biocollection pool to that of BD itself. The most fundamental characteristic of collection, as an information resource, is its scientific signifi cance. The following three main groups of more particular characteristics are distinguished: — the “proper” characteristics of every collection are its meaningfulness, informativeness, reliability, adequacy, documenting, systematicity, volume, structure, uniqueness, stability, lability; — the “external” characteristics of collection are resolution, usability, ethic constituent; — the “service” characteristics of collection are its museofication, storage system security, inclusion in metastructure, cost. In the contemporary world, development of the biocollection pool, as a specific resource for BD research, requires considerable organizational efforts, including work on their “information support” aimed at demonstrating the necessity of existence of the biocollections

The Petrie Museum of Egyptian Archaeology: Characters and Collections

The Petrie Museum of Egyptian Archaeology first opened its doors in 1915, and since then has attracted visitors from all over the world as well as providing valuable teaching resources. Named after its founder, the pioneering archaeologist Flinders Petrie, the Museum holds more than 80,000 objects and is one of the largest and finest collections of Egyptian and Sudanese archaeology in the world. Richly illustrated and engagingly written, the book moves back and forth between recent history and the ancient past, between objects and people. Experts discuss the discovery, history and care of key objects in the collections such as the Koptos lions and Roman era panel portraits. The rich and varied history of the Petrie Museum is revealed by the secrets that sit on its shelves