Fish school search: an interval representation

Fish species compared to animals show complicated behavior mostly to increase their survivability. One may understand the phenomenon by two different ways viz., for mutual protection and for synergic achievements of other collective tasks. As per the literature, there exist some studies related to the above collective goals for finding food by considering the data as a crisp or exact form. But in actual practice the positions of fish at each instant of time may not be obtained in crisp. But those should be taken in uncertain form. Here this uncertainty has been taken in terms of interval. Hence in the thesis, a new form of fish school search has been proposed. Accordingly the interval computation has been implemented to obtain the fish position and hence the optimization process goes in a new direction

The Simulation of the Movement of Fish Schools

In this paper, I explain a school behavior model, which was constructed by Aoki, Huth, and Wissel, used to describe the motion of schools of fish. Schools of fish are characterized by strong cohesion and high parallel orientation without using a leader. In this model, each fish can exhibit one of four basic behavior patterns -- repulsion, parallel orientation, attraction, and search -- based on its proximity to a neighbor fish. I modified the model in how the fish mixed the influence of its neighbors; the fish takes a weighted average of the influences of its neighbors. I constructed a computer simulation model using robots to test this model, and my data has shown that the model is quite successful in simulating the characteristics of a school of fish. The ultimate goal of this research isto apply the school behavior model to algorithms for robot formations

Multibeam volume acoustic backscatter imagery and reverberation measurements in the Northeastern Gulf of Mexico

Multibeam volume acoustic backscatterimagery and reverberation measurements are derived from data collected in 200-m-deep waters in the northeastern Gulf of Mexico, with the Toroidal Volume Search Sonar (TVSS), a 68-kHz cylindrical sonar operated by the U.S. Navy’s Coastal System Station. The TVSS’s 360-degree vertical imaging plane allows simultaneous identification of multiple volume scattering sources and their discrimination from backscatter at the sea surface or the seafloor. This imaging capability is used to construct a three-dimensional representation of a pelagic fish school near the bottom. Scattering layers imaged in the mixed layer and upper thermocline are attributed to assemblages of epipelagic zooplankton. The fine scale patchiness of these scatterers is assessed with the two-dimensional variance spectra of vertical volume scattering strength images in the upper and middle water column. Mean volume reverberation levels exhibit a vertical directionality which is attributed to the volume scattering layers. Boundary echo sidelobe interference and reverberation is shown to be the major limitation in obtaining bioacoustic data with the TVSS. Because net tow and trawl samples were not collected with the acoustic data, the analysis presented is based upon comparison to previous biologic surveys in the northeastern Gulf of Mexico and reference to the bioacoustic literature

Aggregate Implications of Labor-Market Composition

This dissertation comprises three essays on the movements of workers into and out of employment and unemployment---in other words, the composition of the labor market. The first provides an overview. It describes the US economy's ability to create new hires from unemployment and vacancies and some implications for labor--macro models. The second considers fishery management plans in a two-sector, random search environment, where one sector harvests fish. The optimal composition of jobs is described. The third investigates how labor-market composition affects the cyclical behavior of wages informed by random search models and data from the National Longitudinal Survey of Youth 1979, the Current Population Survey, and the Current Employment Statistics program.PHDEconomicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/162995/1/richryan_1.pd