Admissible Hierachic Sets

In this paper we present a solution concept for abstract systems called the admissible hierarchic set. The solution we propose is a refinement of the hierarchic solution, a generalization of the von Neumann and Morgenstern solution. For finite abstract systems we show that the admissible hierarchic sets and the von Neumann and Morgenstern stable sets are the only outcomes of a coalition formation procedure (Wilson, 1972 and Roth, 1984). For coalitional games we prove that the core is either a vN&M stable set or an admissible hierarchic set.

An Approach to the stability of international environmental agreements: the absorbing sets solution

We study international environmental negotiations when agreements between countries can not be binding. A problem with this kind of negotiations is that countries have incentives for free-riding from such agreements. We develope a notion of equilibrium based on the assumption that countries can create and dissolve agreements in their seeking of a larger welfare. This approach leads to a larger degree of cooperation compared to models based on the internal-external stability approach.

The von Neumann-Morgenstern stable sets for 2x2 games

We analyze the von Neumann and Morgenstern stable sets for the mixed extension of 2 2 games when only single profitable deviations are allowed. We show that the games without a strict Nash equilibrium have a unique vN&M stable set and otherwise they have infinite sets.

Numeric Calculation for Transient Thermal Stress Field in Wall-Shape Metal Part During Laser Direct Forming

In order to investigate the transient thermal stress field in wall-shape metal part during laser direct forming, a FEM model basing on ANSYS is established, and its algorithm is also dealt with. Calculation results show that while the wall-shape metal part is being deposited, in X direction, the thermal stress in the top layer of the wall-shape metal part is tensile stress and in the inner of the wall-shape metal part is compressive stress. The reason causing above-mentioned thermal stress status in the wall-shape metal part is illustrated, and the influence of the time and the processing parameters on the thermal stress field in wall-shape metal part is also studied. The calculation results are consistent with experimental results in tendency.

Scenario sets

The outputs from the pilot work with CIBT to develop scenario guide based on existing work across European business, adding an education and more specifically IT perspective to generic scenarios.

Distribution of Atlantic menhaden, Brevoortia tyrannus, purse-seine sets and catches from southern New England to North Carolina, 1985-96

Sets and catches of Atlantic menhaden, Brevoortia tyrannus, made in 1985-96 by purse-seine vessels from Virginia and North Carolina were studied by digitizing and analyzing Captain's Daily Fishing Reports (CDFR's), daily logs of fishing activities completed by captains of menhaden vessels. 33,674 CDFR's were processed, representing 125,858 purse-seine sets. On average, the fleet made 10,488 sets annually. Virginia vessels made at least one purse-seine set on 67%-83% of available fishing days between May and December. In most years, five was the median number of sets attempted each fishing day. Mean set duration ranged from 34 to 43 minutes, and median catch per set ranged from 15 to 30 metric tons (t). Spotter aircraft assisted in over 83% of sets overall. Average annual catch in Chesapeake Bay (149,500 t) surpassed all other fishing areas, and accounted for 52% of the fleet's catch. Annual catch from North Carolina waters (49,100 t) ranked a distant second. Fishing activity in ocean waters clustered off the Mid-Atlantic states in June-September, and off North Carolina in November-January. Delaware Bay and the New Jersey coast were important alternate fishing grounds during summer. Across all ocean fishing areas, most sets and catch occurred within 3 mi. of shore, but in Chesapeake Bay about half of all fishing activity occurred farther offshore. In Virginia, areas adjacent to fish factories tended to be heavily fished. Recent regulatory initiatives in various coastal states threaten the Atlantic menhaden fleet's access to traditional nearshore fishing grounds. (PDF file contains 26 pages.)

Variation in size of yellowfin tuna (Thunnus albacares) within individual purse-seine sets

ENGLISH:Length-frequency samples of yellowfin tuna from 276 individual purse-seine sets were examined. Evidence of schooling by size is presented. Yellowfin schooled with skipjack are smaller and more homogeneous in length than are yellowfin from pure schools. Yellowfin in schools associated with porpoise appear to be more variable in size than yellowfin from other types of schools. No relationship was found between the tonnage of yellowfin in a school and the mean length of the yellowfin. Despite the tendency to school by size, the size variation within individual schools was judged to be enough to complicate greatly any program of regulation aimed at maximizing the yield-per-recruit through increasing the minimum size of yellowfin at first capture. SPANISH: Fueron examinadas las muestras frecuencia-longitud de atún aleta amarilla, de 276 lances individuales de redes de cerco. Se presenta la evidencia de agrupación por tamaños. Los atunes aleta amarilla agrupados con barrilete, son más pequeños y más homogéneos en longitud, que los atunes aleta amarilla de cardúmenes puros. El atún aleta amarilla en cardúmenes asociados con delfines parece ser más variable en tamaño, que el atún aleta amarilla proveniente de otros tipos de cardúmenes. No se encontró relac¡'ón entre el tonelaje del atún aleta amarilla en un cardumen y la longitud media de esta especie. A pesar de la tendencia a agruparse por tamaño, se juzgó, que la variación de tamaño en cardúmenes individuales, sería suficiente para complicar grandemente cualquier programa de reglamentación, dirigido a obtener el máximo del rendimiento por recluta a través del incremento del tamaño mínimo del atún aleta amarilla en la primera captura.