London School of Economics and Political Science

About: London School of Economics and Political Science is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Politics & Population. The organization has 8759 authors who have published 35017 publications receiving 1436302 citations.

Structural risk minimization over data-dependent hierarchies

Abstract: The paper introduces some generalizations of Vapnik's (1982) method of structural risk minimization (SRM). As well as making explicit some of the details on SRM, it provides a result that allows one to trade off errors on the training sample against improved generalization performance. It then considers the more general case when the hierarchy of classes is chosen in response to the data. A result is presented on the generalization performance of classifiers with a "large margin". This theoretically explains the impressive generalization performance of the maximal margin hyperplane algorithm of Vapnik and co-workers (which is the basis for their support vector machines). The paper concludes with a more general result in terms of "luckiness" functions, which provides a quite general way for exploiting serendipitous simplicity in observed data to obtain better prediction accuracy from small training sets. Four examples are given of such functions, including the Vapnik-Chervonenkis (1971) dimension measured on the sample.

Chapter 48 – Micro-Foundations of Urban Agglomeration Economies

Abstract: This handbook chapter studies the theoretical micro-foundations of urban agglomeration economies. We distinguish three types of micro-foundations, based on sharing, matching, and learning mechanisms. For each of these three categories, we develop one or more core models in detail and discuss the literature in relation to those models. This allows us to give a precise characterisation of some of the main theoretical underpinnings of urban agglomeration economies, to discuss modelling issues that arise when working with these tools, and to compare different sources of agglomeration economies in terms of the aggregate urban outcomes they produce as well as in terms of their normative implications.

Constructing and contesting legitimacy and accountability in polycentric regulatory regimes

Abstract: The legitimacy and accountability of polycentric regulatory regimes, particularly at the transnational level, has been severely criticized, and the search is on to find ways in which they can be enhanced. This paper argues that before developing even more proposals, we need to pay far greater attention to the dynamics of accountability and legitimacy relationships, and to how those in regulatory regimes respond to them. The article thus first seeks to develop a closer analysis of three key elements of legitimacy and accountability relationships which it suggests are central to these dynamics: The role of the institutional environment in the construction of legitimacy, the dialectical nature of accountability relationships, and the communicative structures through which accountability occurs and legitimacy is constructed. Second, the article explores how organizations in regulatory regimes respond, or are likely to respond, to multiple legitimacy and accountability claims, and how they themselves seek to build legitimacy in complex and dynamic situations. The arguments developed here are not normative: There is no ‘‘grand solution’’ proposed to the normative questions of when regulators should be considered legitimate or how to make them so. Rather, the article seeks to analyse the dynamics of legitimacy and accountability relationships as they occur in an attempt to build a more realistic foundation on which grander ‘‘how to’’ proposals can be built. For until we understand these dynamics, the grander, normative arguments risk being simply pipe dreams – diverting, but in the end making little difference.

Diversity and specialisation in cities. Why, where and when does it matter?

Abstract: Summary. Why are some cities specialised and others diversie ed? What are the advantages and disadvantages of urban specialisation and diversity? To what extent do the structure of cities and the activities of e rms and people in them change over time? How does the sectoral composition of cities ine uence their evolution? To answer these and related questions, we e rst distil some key stylised facts from the empirical literature on cities and the composition of their activities. We then turn to a review of different theories looking at such issues, and study the extent to which these theories contribute to the understanding of the empirical regularities.

The rate of obsolescence of knowledge, research gestation lags, and the private rate of return to research resources

Abstract: This paper points out the conceptual distinction between the rates of decay in the physical productivity of traditional capital goods and that of the appropriate revenues accruing to knowledge-producing activities, and notes that it is the latter parameter which is required in any study which constructs a stock of privately marketable knowledge The rate of obsolescence of knowledge is estimated from a simple patent renewal and the estimates are found to be comparable to evidence provided by firms on the lifespan of the output of their R&D activities These estimates, together with mean R&D gestation lags, are then used to correct previous estimates of the private excess rate of return to investment in research We find that after the correction, the private excess rate of return to investment in research, at least in the early 1960's, was close to zero, which may explain why firms reduced the fraction of their resources allocated to research over the subsequent decade