bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the specialization of online program specializers
Authors: Ruf Erik , Weise Daniel 
Published: November 2008

AbstractA common technique for improving the speed of program specialization is to specialize the program specializer itself on the program to be specialized, creating a custom program generator. Much research has been devoted to the problem of generating efficient program generators, which do not perform reductions at program generation time which could instead have been performed when the program generator was constructed. The conventional wisdom holds that only program specializers using binding-time approximations can be specialized into such efficient program generators. This paper argues that this is not the case, and demonstrates that the specialization of a nontrivial online program specializer similar to the original ‘naive MIX’ can indeed yield an efficient program generator. The key to our argument is that, while the use of binding-time information at program generator generation time is necessary for the construction of an efficient custom specializer, the use of explicit binding-time approximation techniques is not. This allows us to distinguish the problem at hand (i.e. the use of binding-time information during program generator generation) from particular solutions to that problem (i.e. offline specialization). We show that, given a careful choice of specializer data structures, and sufficiently powerful specialization techniques, binding-time information can be inferred and utilized without explicit approximations. This allows the construction of efficient, optimizing program generators from online program specializers.
Typing first-class continuations in ML
Authors: Harper Robert , Duba Bruce F. , Macqueen David 
Published: November 2008

AbstractAn extension of ML with continuation primitives similar to those found in Scheme is considered. A number of alternative type systems are discussed, and several programming examples are given. A continuation-based operational semantics is defined for a small, purely functional language, and the soundness of the Damas–Milner polymorphic type assignment system with respect to this semantics is proved. The full Damas–Milner type system is shown to be unsound in the presence of first-class continuations. Restrictions on polymorphism similar to those introduced in connection with reference types are shown to suffice for soundness.
An overview of the Flagship system
Authors: Keane John A. 
Published: November 2008

AbstractThe Flagship Project1 was a research collaboration between the University of Manchester, Imperial College London and International Computers Ltd. The project was unusual in that it aimed to produce a complete computing system based on a declarative programming style. Three areas of a declarative system were addressed: (1) programming languages and programming environments; (2) the machine architecture and computational models; and (3) the software environment. This overview paper discusses each of these areas, the intention being to present the project as a coherent whole.
How powerful are folding/unfolding transformations?
Authors: Zhu Hong 
Published: November 2008

AbstractThis paper discusses the transformation power of Burstall and Darlington's folding/unfolding system, i.e. what kind of programs can be derived from a given one. A necessary condition of derivability is proved. The notion of inherent complexity of recursive functions in introduced. A bound on efficiency gain by folding/unfolding transformations is obtained for all reasonable computation models. The well-known partial correctness and incompleteness of the system are corollaries of the result. Examples of underivability are given, e.g. binary searching cannot be derived from linear searching, merge sorting cannot be derived from insert sorting.
Simple type-theoretic foundations for object-oriented programming
Authors: Pierce Benjamin C. , Turner David N. 
Published: November 2008

AbstractWe develop a formal, type-theoretic account of the basic mechanisms of object-oriented programming: encapsulation, message passing, subtyping and inheritance. By modelling object encapsulation in terms of existential types instead of the recursive records used in other recent studies, we obtain a substantial simplification both in the model of objects and in the underlying typed λ-calculus.
Baby Modula-3 and a theory of objects
Authors: Abadi Martin 
Published: November 2008

AbstractBaby Modula-3 is a small, functional, object-oriented programming language. It is intended as a vehicle for explaining the core of Modula-3 from a biased perspective: Baby Modula-3 includes the main features of Modula-3 related to objects, but not much else. To the theoretician, Baby Modula-3 provides a tractable, concrete example of an object-oriented language, and we use it to study the formal semantics of objects. Baby Modula-3 is defined with a structured operational semantics and with a set of static type rules. A denotational semantics guarantees the soundness of this definition.
Strong normalisation for the linear term calculus
Authors: Benton P. N. 
Published: November 2008

AbstractWe prove a strong normalisation result for the linear term calculus of Benton, Bierman, Hyland and de Paiva. Rather than prove the result from first principles, we give a translation of linear terms into terms in the second-order polymorphic lambda calculus (λ2) which allows the result to be proved by appealing to the well-known strong normalisation property of λ2. An interesting feature of the translation is that it makes use of the λ2 coding of a coinductive datatype as the translation of the !-types (exponentials) of the linear calculus.
On-line and off-line partial evaluation: semantic specifications and correctness proofs
Authors: Consel Charles , Khoo Siau Cheng 
Published: November 2008

AbstractThis paper presents semantic specifications and correctness proofs for both on-line and offline partial evaluation of strict first-order functional programs. To do so, our strategy consists of defining acore semanticsas a basis for the specification of three non-standard evaluations: instrumented evaluation, on-line and off-line partial evaluation. We then use the technique oflogical relationsto prove the correctness of both on-line and off-line partial evaluation semantics.The contributions of this work are as follows:1. We provide auniform frameworkto defining and proving correct both on-line and off-line partial evaluation.2. This work required a formal specification of on-line partial evaluation with polyvariant specialization. We define criteria for its correctness with respect to an instrumented standard semantics. As a by-product, on-line partial evaluation appears to be based on a fixpoint iteration process, just like binding-time analysis.3. We show that binding-time analysis, the preprocessing phase of off-line partial evaluation, is anabstractionof on-line partial evaluation. Therefore, its correctness can be proved with respect to on-line partial evaluation, instead of with respect to the standard semantics, as is customarily done.4. Based on the binding-time analysis, we formallyderivethe specialization semantics for off-line partial evaluation. This strategy ensures the correctness of the resulting semantics.
Communication lifting: fixed point computation for parallelism
Authors: Vree Willem G. , Hartel Pieter H. 
Published: November 2008

AbstractCommunication lifting is a program transformation that can be applied to a synchronous process network to restructure the network. This restructuring in theory improves sequential and parallel performance. The transformation has been formally specified and proved correct and it has been implemented as an automatic program transformation tool. This tool has been applied to a small set of programs consisting of synchronous process networks. For these networks communication lifting generates parallel programs that do not require locking. Measurements indicate performance gains in practice both with sequential and parallel evaluation. Communication lifting is a worthwhile optimization to be included in a compiler for a lazy functional language.
Refining reduction in the lambda calculus
Authors: Kamareddine Fairouz , Nederpelt Rob 
Published: November 2008

AbstractWe introduce a λ-calculus notation which enables us to detect in a term, more β-redexes than in the usual notation. On this basis, we define an extended β-reduction which is yet a subrelation of conversion. The Church Rosser property holds for this extended reduction. Moreover, we show that we can transform generalised redexes into usual ones by a process called ‘term reshuffling’.
Functional Pearls
Authors: Gibbons Jeremy 
Published: November 2008

AbstractThetree-drawing problemis to produce a ‘tidy’ mapping from elements of a tree to points in the plane. In this paper, we derive an efficient algorithm for producing tidy drawings of trees. The specification, the starting point for the derivations, consists of a collection of intuitively appealingcriteriasatisfied by tidy drawings. The derivation shows constructively that these criteria completely determine the drawing. Indeed, the criteria completely determine a simple but inefficient algorithm for drawing a tree, which can be transformed into an efficient algorithm using just standard techniques and a small number of inventive steps.The algorithm consists of anupwards accumulationfollowed by adownwards accumulationon the tree, and is further evidence of the utility of these two higher-order tree operations.
A positive supercompiler
Authors: Sørensen M. H. , Glück R. , Jones N. D. 
Published: November 2008

AbstractWe introduce apositive supercompiler, a version of Turchin's supercompiler maintaining only positive information during transformation, and using folding without generalization. The positive supercompiler can also be regarded as a variant of Wadler's deforestation maintaining an increased amount of information. We compare our algorithm to deforestation and, in less detail, to partial evaluation, Turchin's supercompiler, Generalized Partial Computation (GPC), and partial deduction by classifying these transformers by the amount of information they maintain during transformation. This factor is significant, as a differentiating example reveals: positive supercompilation, Turchin's supercompiler, GPC and partial deduction can specialize a general pattern matcher with respect to a fixed pattern to obtain an efficient matcher very similar to the Knuth–Morris–Pratt algorithm. Deforestation and traditional partial evaluation achieve this effect only after a non-trivial hand rewriting of the general matcher.
Numerical solution of multivariate polynomial systems by homotopy continuation methods
Authors: Li T. Y. 
Published: November 2008

LetP(x) = 0 be a system ofnpolynomial equations innunknowns. DenotingP= (p1,…,pn), we want to find all isolated solutions offorx= (x1,…,xn). This problem is very common in many fields of science and engineering, such as formula construction, geometric intersection problems, inverse kinematics, power flow problems with PQ-specified bases, computation of equilibrium states,etc.Elimination theory-based methods, most notably the Buchberger algorithm (Buchberger 1985) for constructing Gröbner bases, are the classical approach to solving (1.1), but their reliance on symbolic manipulation makes those methods seem somewhat unsuitable for all but small problems.
Current approaches and future directions for contaminant-related impact assessments in coastal environments: Brazilian perspective
Authors: Nipper M. 
Published: November 2008

AbstractCoastal ecosystems are subject to the discharge of contaminants via sewage, industrial effluents, storm water runoff, dredged material and accidental chemical spills. The majority of contaminants reaching the ocean tend to be adsorbed to particulate matter and eventually settle on the ocean floor, where they can deleteriously affect the sediment-associated community. The degree to which a receiving body is impacted is usually assessed by the analysis of the sediments from the area of concern. If chemical data generated by monitoring programs are available, they can be compared to Sediment Quality Guidelines to help identify a potential problem. A more cost-effective approach involves the use of a sensitive toxicity test to identify areas of concern, with comprehensive chemical analyses conducted at a later stage and focusing on the toxic sites identified in the initial screening survey. More complex studies involve the assessment of the benthic communities, in addition to toxicity tests and chemical analyses can be conducted. While methodologies for chemical and benthic community assessments are relatively well established, several approaches can be used to determine sediment toxicity, including acute or chronic tests, conducted in the laboratory or in situ, on the whole sediment or the liquid phase. Several factors should be considered when interpreting toxicity test results, such as the enhancement of toxicity by the photo-oxidation of organic chemicals by ultraviolet light (UV), and confounding factors such as salinity, ammonia, sulfides, particle size distribution, organic matter content, and acid volatile sulfides (AVS). Once an impact has been identified, toxicity identification evaluation (TIE) procedures can be applied to help establish the chemical or classes of chemicals responsible for the observed adverse effects. The international and Brazilian scientific literatures are reviewed to illustrate these approaches.
Land use, habitat, and water quality effects on macroinvertebrate communities in three watersheds of a lake michigan associated marsh system
Authors: Stewart P.M. , Butcher J.T. , Swinford T.O. 
Published: November 2008

AbstractThree watersheds within a marsh system draining into Lake Michigan in northwest Indiana, USA, were studied for differences among land use, habitat conditions and water quality to determine their influence on macroinvertebrate community structure. Much of this area had been altered for agricultural, commercial, industrial and residential land uses. Land use, habitat conditions and water quality were significantly different among watersheds. Water quality varied more among streams than within streams. Several variables were related to land use, especially dissolved ions. Macroinvertebrate communities depicted neither a healthy wetland nor a healthy stream system. Some sites were typical of a sand-based, erosional stream system and others were more typical of a wetland system. Communities were different both in and among streams; relationships with water chemistry variables and land use suggested that community structure was a function of local-scale, abiotic factors rather than watershed-scale characteristics. These results show the importance of local-scale influences on the structure and function of macroinvertebrate communities. The development of the methods used to measure these local-scale landscape factors is important to restoration and management.
Monitoring and assessment of the environment in the Lake Baikal region
Authors: Anokhin Yu.A. , Izrael Yu.A. 
Published: November 2008

Abstract
Analysis of many years’ observations of the environment in the Lake Baikal basin leads to the conclusion that the levels of pollutants in Baikal are extremely low, scarcely above the global background of biospheric pollution.
Economic activity in the Baikal watershed basin is a potential threat to the environment. The main influences are global environment and climate change, the Irkutsk dam on the Angara River and pollution of the environment. These impacts have been analyzed on a regional basis. Since the early 1970s routine information has come from monitoring programs for the Lake Baikal.
Models (dynamic and statistical) have been developed to describe and predict changes in the state of the environment (ambient air and precipitation, waters of the Lake Baikal and the tributaries, soils of the region and lake sediment, biota).
Hydrochemistry of southern Lake Baikal
Authors: Grosheva E.I. , Loseva R.P. , Sudakova N.D. , Kusner Y.S. 
Published: November 2008

Abstract
Recent chemical indices of water quality of southern Lake Baikal are given: colour, pH, BOD, COD and the principal ions. Chemical homogeneity and stability of the ionic composition of Lake Baikal water compared to observations in the last 30 years was confirmed.
Estimation of the influence of the Chernobyl accident on the Baikal drainage basin
Authors: Politov S.V. , Anokhin Yu.A. 
Published: November 2008

Abstract
For the first time, contamination levels of cesium due to the Chernobyl accident in water of highland lakes (and soils from their watersheds) of the Lake Baikal drainage basin, have been measured. The reason for this study was that the main long-range transportation of Chernobyl accident products in an easterly direction took place at high altitudes (above 2 km).
The amount of Chernobyl 137Cs, estimated on the basis of 134Cs content, varied in soils from 2 to 7% in the low-mountain areas, from 13 to 16% in the highlands and from 23 to 34% in the water of highland lakes. The estimated total deposition of cesium in the Baikal drainage basin was estimated to be 0.3% of the total Chernobyl emission.
Assessing pollution and UV-enhanced toxicity in Torsviken, Sweden, a shallow bay exposed to contaminated dredged harbor sediment and hazardous waste leachate
Authors: Wernersson A.-S. , Dave G. , Nilsson E. 
Published: November 2008

AbstractTorsviken is a small bay close to the city of Gothenburg, Sweden. Part of the bay has been used for disposal of dredged harbor sediment since the 1970s. Other potential sources of contamination are a deposit site and treatment facility for hazardous waste. The area has been classified as ecologically sensitive and is of great ornithological interest. Birds are abundant and several rare species have been observed. In this study, pollution was assessed by analyzing concentrations of polycyclic aromatic hydrocarbons, polychlorinated biphenyls and heavy metals and by measuring toxicity of sediment samples to Daphnia magna, Nitocra spinipes, Chironomus riparius and Hyalella azteca. The combined exposure to several contaminants and solar light can enhance toxic effects, and since Torsviken is a shallow bay (maximum depth 2 m), organisms surviving the bioassays were exposed to simulated ultraviolet (UV) light of site-relevant intensity for 2 h to detect potential UV-enhanced toxicity. Torsviken is subdivided into three basins and the concentrations of most investigated contaminants, especially polycyclic aromatic hydrocarbons and polychlorinated biphenyls, were 2–5 times higher in the inner (western) area compared to the outer (eastern) areas. Acute sediment toxicity was found primarily in Nitocra, but there was no clear difference between the two areas of Torsviken. Ultraviolet-induced toxicity also occurred especially in Nitocra but only in the western area where organic pollutants are elevated in concentration. In the same sediment sampling site that caused the highest increase in mortality in Nitocra, there was also a significant response by Daphnia after UV treatment. Correlations between the toxicity enhancement (measured as % of surviving Nitocra from the bioassays that died after subsequent exposure to UV light) and chemical concentrations were found for several of the pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, mercury and lead, indicating that some of these substances were bioavailable and induced toxicity with UV irradiation. The results support the need to develop special sediment quality guidelines for shallow sites, where the phototoxic properties of pollutants should be accounted for.
Biological impact of lipophilic sediment extracts from the Kafue River, Zambia, in microinjected rainbow trout yolk-sac fry and chick embryo livers exposed in vitro
Authors: Norrgren L. , Brunström B. , Engwall M. , Mwase M. 
Published: November 2008

Abstract
Lipophilic sediment extract originating from the Kafue River, Zambia, was evaluated for toxic potency. Two different bioassays were used. In the first, sediment extracts were injected into newly hatched rainbow trout yolk-sac fry, and in the second chick embryo livers were incubated in vitro in different concentrations of the sediment extract. A dose-dependent ethoxyresofurin-O-deethylase (EROD) induction was recorded in both experiments. Furthermore, various types of intracellular alterations characterized by degenerative and necrotic changes were observed in the hepatocytes of the exposed groups. These findings indicate the presence of EROD inducing dioxin-like lipophilic substances in sediment extracts originating from the Kafue River near the town of Kitwe.
The ecosystem pyramid and the means for attaining ecological sustainability: an essay in honour of Jack Christie
Authors: Minns C.K. 
Published: November 2008

Abstract
This essay is presented in honour of Jack Christie and his life-long dedication to the promotion of an ecosystem approach to the management of human affairs in the biosphere. The essay has four sections. First, I review and reflect on the personal and professional interactions I had with Jack Christie for more than 25 years. Those interactions often centred on questions of ecosystem management in the Great Lakes and beyond, but especially in the Bay of Quinte area where Jack lived and worked. Second, I consider the role of metaphorical symbols in shaping our interactions with and behaviour towards ecosystems. I offer arguments for adopting a metaphor—an ecosystem is a stepped pyramid—as a basis for shifting our thinking mode regarding ecosystems. Third, I turn to an examination of some of the means by which human society might return to ecological sustainability. I describe and compare ecological, social, and economic mechanisms. Fourth, given the current situation and the options, I conclude with a personal view of our future prospects.