Two New Location Covering Problems: The Partial P-Center Problem and the Partial Set Covering Problem

Two new covering problems are introduced. The partial covering P-center problem minimizes a coverage distance in such a way that a given fraction of the population is covered. The partial set covering problem seeks the minimum number of facilities needed to cover an exogenously specified fraction of the population within a given coverage distance. The problems are formulated as integer linear programming problems. Bisection search algorithms are outlined for the two problems. The search algorithm repeatedly solves a Lagrangian relaxation of the maximal covering problem. Computational results for the Lagrangian relaxation of the maximal covering problem and for the bisection search algorithms are presented on problems with up to 150 nodes.     

Two New Location Covering Problems: The Partial P-Center Problem and the Partial Set Covering Problem

Two new covering problems are introduced. The partial covering P-center problem minimizes a coverage distance in such a way that a given fraction of the population is covered. The partial set covering problem seeks the minimum number of facilities needed to cover an exogenously specified fraction of the population within a given coverage distance. The problems are formulated as integer linear programming problems. Bisection search algorithms are outlined for the two problems. The search algorithm repeatedly solves a Lagrangian relaxation of the maximal covering problem. Computational results for the Lagrangian relaxation of the maximal covering problem and for the bisection search algorithms are presented on problems with up to 150 nodes.     

A Comparative Analysis of Farmland Preservation Programmes in North America

During the last two decades, in Canada and the United States, provincial and state governments have responded to the issue of farmland preservation with a variety of measures. These are examined within the context of political and social acceptability, cost of implementation, and impact. A typology of generic farmland protection strategies is developed to classify the state and provincial responses, with consideration given to the relative effectiveness of each. Of the four distinct policy approaches that emerge, the comprehensive-mandatory programmes are considered to promise the greatest success.
Au cows des deux dernières décennies, au Canada et dans les États-Unis, les gouvernements des provinces et des états ont adopté des politiques tres variées afin de preserver le territoire agricole. Ces politiques sont analysees dans le lut de determiner si leur mise en oeuvre est acceptable au point de vue politique et social et d'Cvaluer leur coût aussi que leur efficacité. Une typologie des strategies de conservation bade sur leurs caracteristiques génériques sert à classifier les diverses politiques, notamment eu égard à leur efficacité relative. Des quatre approches de politique qui ressortent de cette étude, celle basée sur des programmes obligatoires et globaux semble la plus prometteuse.     

Reviews

M. Philips Price: “A HISTORY OF TURKEY: FROM EMPIRE TO REPUBLIC” (Allen and Unwin. 1956. 20/‐.)

“THE ECONOMICS OF EMPLOYMENT AND UNEMPLOYMENT.” By Paul H. Casselman. (Public Affairs Press, Washington, D.C., 1955, pp. vi plus 183. Price $3.25.)

“THE HISTORY OF A SOVIET COLLECTIVE FARM.” Fedor Belov. Routledge. London. International Library of Sociology and Social Reconstruction. 1956. xiii plus 234, including appendices and index. 21/‐.

“RED, BLACK, BLOND AND OLIVE.” by Edmund Wilson. (W. H. Allen, London. 25/‐.)

“THE PATTERN OF WORLD CONFLICT.” by G. L. Arnold. London. (The Dial Press, New York. 1955, pp. 250.)

“FLIGHT AND RESETTLEMENT.” by H. B. Murphy and Others. (Paris: United Nations Educational, Scientific and Cultural Organization), 1955, pp.231.