An Integrated Planning Representation Using Macros, Abstractions, and Cases

Planning will be an essential part of future autonomous robots and integrated intelligent systems. This paper focuses on learning problem solving knowledge in planning systems. The system is based on a common representation for macros, abstractions, and cases. Therefore, it is able to exploit both classical and case based techniques. The general operators in a successful plan derivation would be assessed for their potential usefulness, and some stored. The feasibility of this approach was studied through the implementation of a learning system for abstraction. New macros are motivated by trying to improve the operatorset. One heuristic used to improve the operator set is generating operators with more general preconditions than existing ones. This heuristic leads naturally to abstraction hierarchies. This investigation showed promising results on the towers of Hanoi problem. The paper concludes by describing methods for learning other problem solving knowledge. This knowledge can be represented by allowing operators at different levels of abstraction in a refinement

The impact of Mexican immigrants on U.S. wage structure

Previous study by Card and Lewis (2005) has found (puzzling) that inflows of Mexican immigrants into “new” metropolitan areas have had no effect on the relative wages of very low-skill (high school dropouts). Rather, Mexican workers do affect relative wages for high school graduates. Whereas Card and Lewis’ study uses variations across geographies, this paper considers variations across occupations. Recognizing that Mexican immigrants are highly occupationally clustered (disproportionately work in distinctive “very low wage” occupations), we use this fact to motivate the empirical approach to analyze the relationship between the composition of Mexican immigrants across occupations/industries and average wages in the occupations/industries. To summarize our finding, we confirm that in spite of the fact that Mexican immigrants are disproportionately in “very low skill” occupations, (which we define as occupations where the average workers have no high school education), we find no significant impact of Mexican immigrants on wages in those occupations. By contrast, inflows of Mexican immigrants have some small effects on the wages of native workers in “low skill” occupations (which we define as occupations where the average worker has at least some high school education or is a high school graduate). These results suggest potential “spill over effects” as natives may be reallocating their labor supply into non-predominant Mexican occupations. An analysis of employment changes of natives into different occupation groupings in response to an inflow of Mexican immigrants, confirms that natives’ employment in occupations where the average worker has a high school education increases in response to Mexican inflows in the U.S labor force from previous periods.Immigrants ; Wages

The regional economic impact of more graduates in the labour market: a “micro-to-macro” analysis for Scotland

This paper explores the system-wide impact of graduates on the regional economy. Graduates enjoy a significant wage premium, often interpreted as reflecting their greater productivity relative to non-graduates. If this is so there is a clear and direct supply-side impact of HEI activities on regional economies. We use an HEI-disaggregated computable general equilibrium model of Scotland to estimate the impact of the growing proportion of graduates in the Scottish labour force that is implied by the current participation rate and demographic change, taking the graduate wage premium in Scotland as an indicator of productivity enhancement. While the detailed results vary with alternative assumptions about the extent to which wage premia reflect productivity, they do suggest that the long-term supply-side impacts of HEIs provide a significant boost to regional GDP. Furthermore, the results suggest that the supply-side impacts of HEIs are likely to be more important than the expenditure impacts that are the focus of most HEI impact studies

CLIP: concept learning from inference patterns

AbstractA new concept-learning method called CLIP (concept learning from inference patterns) is proposed that learns new concepts from inference patterns, not from positive/negative examples that most conventional concept learning methods use. The learned concepts enable an efficient inference on a more abstract level. We use a colored digraph to represent inference patterns. The graph representation is expressive enough and enables the quantitative analysis of the inference pattern frequency. The learning process consists of the following two steps: (1) Convert the original inference patterns to a colored digraph, and (2) Extract a set of typical patterns which appears frequently in the digraph. The basic idea is that the smaller the digraph becomes, the smaller the amount of data to be handled becomes and, accordingly, the more efficient the inference process that uses these data. Also, we can reduce the size of the graph by replacing each frequently appearing graph pattern with a single node, and each reduced node represents a new concept. Experimentally, CLIP automatically generates multilevel representations from a given physical/single-level representation of a carry-chain circuit. These representations involve abstract descriptions of the circuit, such as mathematical and logical descriptions

Human and physical infrastructure : public investment and pricing policies in developing countries

Almost by definition, the basis for development is infrastructure - whether services for human infrastructure (health, education, nutrition) or physical infrastructure (transport, energy, water). Although the infrastructure sectors are diverse, what they have in common is that public policy has had a great deal to do with how these services are provided and financed in almost all countries. The author reviews the recent literature on two key aspects of that involvement: investment and pricing. While the quality of the econometric evidence varies, recent literature reinforces the view that human and physical infrastructure are critical for economic growth and the reduction of poverty. And the state is recognized as playing a key role in ensuring the efficient, equitable allocation of resources for infrastructure. Despite many sound theoretical reasons for such public involvement, however, recent studies have shown that it leaves much to be desired in efficiency and equity. One symptom is underinvestment in key subsectors that have high economic returns and that help the poor the most, such as primary education and rural health clinics, in relation to more expensive interventions, such as tertiary education and urban hospitals. Another common malaise is the poor use of scarce resources, leading to low quality (students learning little) and reliability (irregular power and water flows), poor maintenance (dilapilated roads), and inappropriate input use (too many school adminstrators or health workers and not enough books or drugs in producing education health outcomes). Just as market failures necessitate government intervention in the infrastructure sectors, so government failures should be considered in deciding the depth and extent of that intervention. The literature has made some advances in diagnosing these problems in poor countries and proposing solutions. But information gaps remain, particularly in developing robust methodologies for: 1) making intersectoral comparisons across the wide range of infrastructure services; 2) crafting more diverse policies about the public-private balance in infrastructure investment, depending on the nature of"public goods"characteristics for various types of infrastructure services, or even across activities for the same service (for example, power transmission versus distribution); and 3) taking issues of political economy into account, such as the vested interests of those with large financial interests in infrastructure. The author also highlights public pricing as a policy initiative that has recently gotten much attention.After briefly reviewing the basic concepts of pricing, he focuses on the literature about pricing reform. Most commonly, the public sector is the main provider of infrastructure services, usually free or at subsidized prices. But the recent literature has aired a rethinking of the balance between public and private financing of infrastructure. The debate in this area is often heated. Health and education are traditionally provided free and some recent literature argues for positive prices, at least for higher tiers of service. The principle of public pricing has been more widely accepted in transport, energy, and to a lesser extent water, but often the levels are too low and do not provide the appropriate incentives for efficient and equitable use.Environmental Economics&Policies,Banks&Banking Reform,Health Monitoring&Evaluation,Public Sector Economics&Finance,Economic Theory&Research

Learning in evolutionary environments

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Extending and Deepening the Analysis of Innovation Systems - with Empirical Illustrations from the DISCO-project

Traditionally innovation system have been analysed either as rooted in the R&Dsystem or the production system. This paper suggests a broader approach to national innovation systems and analyse these as rooted in constellation of a national production structure and human resource development institutions. The argument is linked both to the literature on innovation systems and an empirical account of the Danish innovation system (the DISKO-project) and the economy in general. It is argued that change of the innovation and production system is difficult without a reform of the human resource development system as the dynamics of these two dimensions are closely connected. Results from the DISKO-project are used to illustrate the new analytical and political issues emanating from such a shift in perspective. On the one hand it is shown that the general economic climate in terms of the transformation pressure and the intensity of competition has a major impact on what the firm does in terms of technical innovation and organisational change. On the other hand it is demonstrated how the behaviour of individual firms affect aggregate employment and specifically the employment opportunities of unskilled workers. It is argued that the broader approach to the analysis of innovation systems also calls for a broader policy approach. Innovation is affected by other types of policy than industrial policy and a sharp division between macro-economic and competition policy on the one hand and education, labour market and innovation policy on the other hand is shown to be problematic.innovation systems, human resources, transformation pressure, organisational change

Emerging infrastructure policy issues in developing countries - a survey of the recent economic literature

The author reviews the recent economic research on emerging issues for infrastructure policies affecting poor people in developing countries. His main purpose is to identify some of the challenges the international community, and donors in particular, are likely to have to address over the next few years. He addresses six main issues: (1) the necessity of infrastructure in achieving the Millennium Development Goals; (2) the various dimensions of financing challenges for infrastructure; (3) the debate on the relative importance of urban and rural infrastructure needs; (4) the debate on the effectiveness of infrastructure decentralization; (5) what works and what does not when trying to target the needs of the poor, with an emphasis on affordability and regulation challenges; and (6) the importance of governance and corruption in the sector. The author concludes by showing how the challenges identified define a relatively well integrated agenda for both researchers and the international infrastructure community.Health Economics&Finance,Decentralization,Banks&Banking Reform,Public Sector Economics&Finance,Environmental Economics&Policies,Banks&Banking Reform,Health Economics&Finance,Public Sector Economics&Finance,Environmental Economics&Policies,Poverty Assessment