Finding Minimal Cost Herbrand Models with Branch-Cut-and-Price

Given (1) a set of clauses $T$ in some first-order language $\cal L$ and (2) a cost function $c : B_{{\cal L}} \rightarrow \mathbb{R}_{+}$, mapping each ground atom in the Herbrand base $B_{{\cal L}}$ to a non-negative real, then the problem of finding a minimal cost Herbrand model is to either find a Herbrand model $\cal I$ of $T$ which is guaranteed to minimise the sum of the costs of true ground atoms, or establish that there is no Herbrand model for $T$. A branch-cut-and-price integer programming (IP) approach to solving this problem is presented. Since the number of ground instantiations of clauses and the size of the Herbrand base are both infinite in general, we add the corresponding IP constraints and IP variables `on the fly' via `cutting' and `pricing' respectively. In the special case of a finite Herbrand base we show that adding all IP variables and constraints from the outset can be advantageous, showing that a challenging Markov logic network MAP problem can be solved in this way if encoded appropriately

An Emergent Economics of Ecosystem Management

Economics is an evolving and emerging field of study, so is the management of ecosystems. As such, this paper delineates the co-evolution of economic evaluation that reflects the various recognized ecosystem management approaches of anticipative, adaptive and capacitive ecosystem management. Each management approach is critiqued and from this theoretical analysis an emergent approach for the management of ecosystem is put forward, which accordingly suggests an alternative methodological approach for economic evaluations.Complexity, creativity, economic evaluation, ecosystem management, evolution, open systems, rationality, Resource /Energy Economics and Policy,

Polanyi on institutions and money

The purpose of this contribution is to suggest an interpretation of the substantivist thought initiated by Karl Polanyi. An approach such as this is concerned with « historical economics », in the sense that substantive concepts are the result not of a retrospective projection of modern bias but of an attempt to apprehend universal categories of economic analysis in order to clarify the true particularities of different economic systems1. The point is to show that the coherence of institutionalist thought founded by economists such as Mitchell, Commons and Veblen are in agreement the reflexions of Karl Polanyi who thinks of money as an institution that embeds the economy into social relationships. In this analytical framework, stripping money of its institutional character and trying to reduce it to a commodity is bound to create chaos. It is important to note that, rather than focusing on facts, the paper concerns the history of ideas. Certainly, Polanyi's writings on ancient economy can no longer be wholly accepted, if the evolution of the work of historians is seriously taken into account. But this is not the real issue according to Duncan, Tandy (1994 : 23)2. The history of ideas is the history of problems, which can suggest new interpretations that do not depend substantially on facts. It is interesting to remark that Ian Morris's (1994 : 54) attempt to combine Finley's thesis and Polanyi's insights constitutes a recent attempt to escape from the fallacy of the primitivism/modernism dichotomy3; such a solution has surely been an objective of Polanyi.Money;Polanyi,Institutions;Veblen;Commons;Mitchell,Substantivism

Agricultural Import Demand in Low-Income, Middle-Income, and Centrally Planned Economies

This report provides summaries of the papers and discussions at the third Consortium on Trade Research held in Washington, D.C., June 23-24, 1981. The cochairmen of the consortium were T. Kelley White, Economic Research Service (ERS), George E. Rossmiller, Foreign Agricultural Service (FAS), and Vernon Sorenson, Michigan State University. The Consortium focused on world demand for agricultural imports and the policies and conditions in low-income, middle-income, and centrally planned countries that influence import demand. An overview paper by Dewain Rahe and Cheryl Christensen assessed future global prospects for agricultural trade. Peter Timmer's paper investigated conceptual and empirical problems in analyzing import demand. Three of the papers discussed the demand for food and agricultural products in the Soviet Union and China. Three additional papers focused on factors affecting import demand in low- and middle-income countries. A final set of papers examined the role of bilateral agreements and stockholding policies in agricultural trade.Trade, import demand, projections, state trading, food reserves, stockholding, bilateral agreements, low-income countries, middle-income countries, centrally planned countries, International Relations/Trade,

Region-based memory management for Mercury programs

Region-based memory management (RBMM) is a form of compile time memory management, well-known from the functional programming world. In this paper we describe our work on implementing RBMM for the logic programming language Mercury. One interesting point about Mercury is that it is designed with strong type, mode, and determinism systems. These systems not only provide Mercury programmers with several direct software engineering benefits, such as self-documenting code and clear program logic, but also give language implementors a large amount of information that is useful for program analyses. In this work, we make use of this information to develop program analyses that determine the distribution of data into regions and transform Mercury programs by inserting into them the necessary region operations. We prove the correctness of our program analyses and transformation. To execute the annotated programs, we have implemented runtime support that tackles the two main challenges posed by backtracking. First, backtracking can require regions removed during forward execution to be "resurrected"; and second, any memory allocated during a computation that has been backtracked over must be recovered promptly and without waiting for the regions involved to come to the end of their life. We describe in detail our solution of both these problems. We study in detail how our RBMM system performs on a selection of benchmark programs, including some well-known difficult cases for RBMM. Even with these difficult cases, our RBMM-enabled Mercury system obtains clearly faster runtimes for 15 out of 18 benchmarks compared to the base Mercury system with its Boehm runtime garbage collector, with an average runtime speedup of 24%, and an average reduction in memory requirements of 95%. In fact, our system achieves optimal memory consumption in some programs.Comment: 74 pages, 23 figures, 11 tables. A shorter version of this paper, without proofs, is to appear in the journal Theory and Practice of Logic Programming (TPLP

Human Rights, Persons with Disabilities, ICF and the Convention on the Rights of Persons with Disabilities - Training Toolkit

No abstract available

The substantive economy of money : Karl Polanyi in the tradition of "old institutionalism"

The purpose of this contribution is to suggest an interpretation of substantivist thought initiated by Karl Polanyi. An approach such as this is concerned with “historical economics”, in the precise sense that substantive concepts do not come from a retrospective projection of modern prejudgements, but rather from an attempt to apprehend universal categories of economic analysis in order to clarify the genuine singularities of different economic systems . In doing this I shall highlight the coherence of institutionalist thought founded by economists such as Mitchell, Commons and Veblen, into which the reflections of Karl Polanyi fit. In this way, Polanyi thinks of money as an institution that submerges the economy into social relationships. As an analytical result, stripping money of its institutional character and trying to reduce it to a commodity, can only create chaos. In order to give an account of Polanyi's project, I will show, in the first part of my analysis, how Polanyi wants to move away from the idea that economy is created on pure rational logic.As a result, economy owes its very existence to "institutionalised processes" which produce the very inflexibilities necessary for both collective and individual action. Taking this into account, it is impossible to presuppose the unity of “the cattalactic triad” i. e. external trade, money and markets. From this point on, it is possible, in the second part of this analysis, to specify certain interesting results for the economic history of money. From a transhistorical viewpoint, this institution sets the rules for the quantification and extinction of debts. However, in contrast to modern money, archaic money is characterised by a separation of functions which compel us to talk about “money uses”. Consequently, it is better to speak in terms of accounting and payment practises rather than using the single word of “money”. Furthermore, the independence of money in relation to market is a characteristic of numerous archaic societies. Nevertheless, in spite of their differences, both ancient and modern monies politically produce social integration.Money - Polanyi - Substantivism - Instititutionalisme - Historical Economics

Cultures of innovation of the African poor : common roots, shared traits, joint prospects? ; on the articulation of multiple modernities in African societies and black diasporas in latin America

The globalized Western culture of innovation, as propagated by major aid institutions, does not necessarily lead to empowerment or improvement of the well-being of the stakeholders. On the contrary, it often blocks viable indigenous innovation cultures. In African societies and African Diasporas in Latin America, cultures of innovation largely accrue from the informal, not the formal sector. Crucial for their proper understanding is a threefold structural differentiation: between the formal and informal sector, within the informal sector, according to class, gender or religion, and between different transnational social spaces. Different innovation cultures may be complementary, mutually reinforcing, or conflicting, leading in extreme cases even to a ‘clash of cultures’ at the local level. The repercussions of competing, even antagonistic agencies of innovative strategic groups are demonstrated, analyzing the case of the African poor in Benin and the African Diasporas of Brazil and Haiti.Die globalisierte westliche Innovationskultur, wie sie von den großen Entwicklungshilfeinstitutionen propagiert wird, führt nicht notwendigerweise zur Verbesserung der Lebensbedingungen der Armen. Sie blockiert im Gegenteil oft wertvolle Ansätze endogener kultureller Innovationen. In afrikanischen Gesellschaften und in der Afrikanischen Diaspora Lateinamerikas entstehen Innovationskulturen überwiegend im informellen, nicht im formellen Sektor. Diese Innovationskulturen weisen eine dreifache strukturelle Differenzierung auf: zwischen formellem und informellem Sektor, innerhalb des informellen gemäß sozialer Schichtung, Geschlecht oder Religion sowie zwischen transnationalen sozialen Räumen. Diese unterschiedlichen Innovationskulturen können sich gegenseitig ergänzen und verstärken oder aber auch bekämpfen, was in Extremfällen bis hin zum „Kampf der Kulturen“ auf lokaler Ebene führt. Die Auswirkungen dieser konkurrierenden oder antagonistischen Handlungsstrategien innovativer strategischer Gruppen werden an Hand von Fallstudien der Armen in Benin und in der Afrikanischen Diaspora Brasiliens und Haitis aufgezeigt

Factors affecting innovation revisited

El propósito de este trabajo es contribuir a un mejor conocimiento de los factores que afectan a la innovación mediante el análisis de los microdatos de la encuesta de innovación de las empresas españolas de 2003. El estudio se aborda desde la elaboración de una taxonomía de sectores combinando las Ventajas Tecnológicas Reveladas de la industria española con el dinamismo tecnológico mundial; además se introduce una clasificación de las empresas en función de la pertenencia o no a un grupo de empresas y de si esos grupos son de nacionalidad española o extranjera. Se utilizan técnicas de Análisis Factorial para reducir y organizar la abundante información disponible en Factores con significado económico que después son empleados como variables explicativas de la innovación de producto y de proceso. Se encuentran diferencias entre ambos tipos de innovación tanto por el número de factores significativos como en la intensidad de su capacidad explicativa. La taxonomía elaborada muestra su importancia al mostrar patrones de comportamiento distintos entre los cuatro tipos de casos construidos.The aim of this paper is to contribute to a better understanding of factors affecting innovation by analysing the Spanish manufacturing sector using microdata of the 2003 Spanish Innovation Survey. To enrich the analysis a self developed sectoral taxonomy is used coming from the combination of both of the sectoral Revealed Technological Advantages (RTA) and worldwide technological dynamism of the sectors; moreover firms are classified according to the type of capital ownership: independent companies, companies belonging to a national group and subsidiaries of multinational enterprises. The abundance and heterogeneity of variables advised us to use Factor analysis to reduce and organise the original variables into a number of consistent and theoretically significant factors. We found differences between product and process innovation, both in number of explicative variables (significant independent variables) and in relative effect of independent variables (even, in some cases, a sign change from product to process innovation). Taxonomy matters because of some differences in explanatory (independent) variables for each sector and model explanatory power differences between sectors, and, on the other hand, because of the “non significance” of some significant variables once we control by sectoral taxonomy.Innovation, Factors affecting innovation, Multinational enterprises, Sectoral taxonomies, Spain.