Data mining as a tool for environmental scientists

Over recent years a huge library of data mining algorithms has been developed to tackle a variety of problems in fields such as medical imaging and network traffic analysis. Many of these techniques are far more flexible than more classical modelling approaches and could be usefully applied to data-rich environmental problems. Certain techniques such as Artificial Neural Networks, Clustering, Case-Based Reasoning and more recently Bayesian Decision Networks have found application in environmental modelling while other methods, for example classification and association rule extraction, have not yet been taken up on any wide scale. We propose that these and other data mining techniques could be usefully applied to difficult problems in the field. This paper introduces several data mining concepts and briefly discusses their application to environmental modelling, where data may be sparse, incomplete, or heterogenous

The ambiguity of town planning: innovation or re-interpretation?

The paper questions the nature of town planning as a coherent national strategy throughout Britain at the beginning of the 20th century, by analyzing the specific case study of Portsmouth. In 1912, the city unveiled an urban improvement scheme named Curzon Howe Road. This went to replace an industrial working-class residential area that had been classified as unhygienic and dangerous for the general wellbeing of the inhabitants. Having been conceived in 1910 as a direct response to the 1909 Housing and Town Planning Act, Curzon Howe Road can be regarded as being the first example of town planning in Portsmouth. In itself, the notion of town planning is often recognized as a new form of urban intervention aimed at tackling the problems inherited from the industrial revolution. This paper highlights the ambiguity of the term town planning which - to quote John W. Simpson, the president of the RIBA at the time of the prestigious Town Planning Conference of 1910 - “has different meanings in different mouths” (RIBA, 1911, iv). It also discusses how the notion of town planning in the early years of its practice in Portsmouth represents a transitional stage prior to the more design-oriented solutions of the following years. The paper argues that there was no ‘pre-town planning’ vs. ‘post-town planning’ clear-cut distinction in this case study, which can also be observed in diverse locations in Britain. Furthermore, the research shows how in Portsmouth, town planning was interpreted by its instigators as a fusion between the old (i.e. the 19th century Critical Planning practices and rigid ByeLaw standards) and new means of implementing change. Thus, Portsmouth’s Curzon Howe Road represents an example of hybridization, generated by the struggle between forces of permanence and rupture within the context of urban improvement of the early 1900s. In this lies its significance, as it reassesses the true nature of what town planning signified in its formative years for different towns around Britain

Manufactured housing comes of age: a support network for resident-owned communities

Owners of manufactured homes who cooperatively purchase the park where they live are discovering benefits such as increased value of homes, decreased maintenance costs, faster resale, and willing lenders.Housing - New Hampshire ; Housing - New England

Affine Sessions

Session types describe the structure of communications implemented by channels. In particular, they prescribe the sequence of communications, whether they are input or output actions, and the type of value exchanged. Crucial to any language with session types is the notion of linearity, which is essential to ensure that channels exhibit the behaviour prescribed by their type without interference in the presence of concurrency. In this work we relax the condition of linearity to that of affinity, by which channels exhibit at most the behaviour prescribed by their types. This more liberal setting allows us to incorporate an elegant error handling mechanism which simplifies and improves related works on exceptions. Moreover, our treatment does not affect the progress properties of the language: sessions never get stuck

Speculation, Futures Prices, and the U.S. Real Price of Crude Oil

In this study, we examine the relationship between the U.S. real price of oil and factors that affect its movement over time: futures prices, the value of the dollar, exploration, demand, and supply. All of these variables are treated as jointly endogenous and a reduced form vector error correction model, testing for cointegration amongst the variables, is estimated. We find that for model specifications with short-term futures contracts, supply does indeed dominate price movements in the crude oil market. However, for specifications including longer-term contracts that are inherently more speculative, the real price of oil appears to be determined predominantly by the futures price. Moreover, there is empirical evidence of hoarding in the crude oil market: both oil stocks/inventories and futures prices are found to be positively cointegrated/correlated with each other. From a policy perspective, the results of this analysis indicate that if regulators really wanted to limit speculation in the oil market, it should keep the shorter-term futures contracts and eliminate the more speculative six months futures contracts.futures prices, cointegration, speculation, hoarding

Linearly Typed Dyadic Group Sessions for Building Multiparty Sessions

Traditionally, each party in a (dyadic or multiparty) session implements exactly one role specified in the type of the session. We refer to this kind of session as an individual session (i-session). As a generalization of i-session, a group session (g-session) is one in which each party may implement a group of roles based on one channel. In particular, each of the two parties involved in a dyadic g-session implements either a group of roles or its complement. In this paper, we present a formalization of g-sessions in a multi-threaded lambda-calculus (MTLC) equipped with a linear type system, establishing for the MTLC both type preservation and global progress. As this formulated MTLC can be readily embedded into ATS, a full-fledged language with a functional programming core that supports both dependent types (of DML-style) and linear types, we obtain a direct implementation of linearly typed g-sessions in ATS. The primary contribution of the paper lies in both of the identification of g-sessions as a fundamental building block for multiparty sessions and the theoretical development in support of this identification.Comment: This paper can be seen as the pre-sequel to classical linear multirole logic (CLML). arXiv admin note: substantial text overlap with arXiv:1603.0372

Reversing Single Sessions

Session-based communication has gained a widespread acceptance in practice as a means for developing safe communicating systems via structured interactions. In this paper, we investigate how these structured interactions are affected by reversibility, which provides a computational model allowing executed interactions to be undone. In particular, we provide a systematic study of the integration of different notions of reversibility in both binary and multiparty single sessions. The considered forms of reversibility are: one for completely reversing a given session with one backward step, and another for also restoring any intermediate state of the session with either one backward step or multiple ones. We analyse the costs of reversing a session in all these different settings. Our results show that extending binary single sessions to multiparty ones does not affect the reversibility machinery and its costs

Shirking, Standards and the Probability of Detection

Publisher PD

Towards Reversible Sessions

In this work, we incorporate reversibility into structured communication-based programming, to allow parties of a session to automatically undo, in a rollback fashion, the effect of previously executed interactions. This permits taking different computation paths along the same session, as well as reverting the whole session and starting a new one. Our aim is to define a theoretical basis for examining the interplay in concurrent systems between reversible computation and session-based interaction. We thus enrich a session-based variant of pi-calculus with memory devices, dedicated to keep track of the computation history of sessions in order to reverse it. We discuss our initial investigation concerning the definition of a session type discipline for the proposed reversible calculus, and its practical advantages for static verification of safe composition in communication-centric distributed software performing reversible computations.Comment: In Proceedings PLACES 2014, arXiv:1406.331