10,189 research outputs found
THE VALUE OF IMPROVED WATER QUALITY TO CHESAPEAKE BAY BOATERS
Resource /Energy Economics and Policy,
Estimating Economic Benefits of Allowing a Flexible Window for Maryland Purchases of Sponge Crabs
We estimate that crabmeat industry revenues from processing sponge crabs can increase by at least 56% over the current estimated value of production, from 2.5 million. This gain can be realized by moving from the current fixed opening of the season during which the Maryland industry can purchase sponge crabs to a flexible starting date to the season that lasts the same number of days as the current system. This change would have the added advantage of reducing the variability in revenues that come from processing sponge crabs. Our modeling of the decision to open the season is based on a minimum amount of information. It is expected that with more sophisticated analysis of the market situation during the season, experts can optimize the opening date and increase the revenues even further.Resource /Energy Economics and Policy,
An Approach to Ecosystem-Based Fishery Management
Marine scientists and policymakers are encouraging ecosystem-based fishery management (EBFM), but there is limited guidance on how to operationalize the concept. We adapt financial portfolio theory as a method for EBFM that accounts for species interdependencies, uncertainty, and sustainability constraints. Illustrating our method with routinely collected data available from the Chesapeake Bay, we demonstrate the gains from taking into account species variances and covariances in setting species total allowable catches. We find over the period from 1962–2003 that managers could have increased the revenues from fishing and reduced the variance by employing ecosystem frontiers in setting catch levels.ecosystem-based fishery management, portfolio, trophic modeling, precaution
Heuristic algorithms for the min-max edge 2-coloring problem
In multi-channel Wireless Mesh Networks (WMN), each node is able to use
multiple non-overlapping frequency channels. Raniwala et al. (MC2R 2004,
INFOCOM 2005) propose and study several such architectures in which a computer
can have multiple network interface cards. These architectures are modeled as a
graph problem named \emph{maximum edge -coloring} and studied in several
papers by Feng et. al (TAMC 2007), Adamaszek and Popa (ISAAC 2010, JDA 2016).
Later on Larjomaa and Popa (IWOCA 2014, JGAA 2015) define and study an
alternative variant, named the \emph{min-max edge -coloring}.
The above mentioned graph problems, namely the maximum edge -coloring and
the min-max edge -coloring are studied mainly from the theoretical
perspective. In this paper, we study the min-max edge 2-coloring problem from a
practical perspective. More precisely, we introduce, implement and test four
heuristic approximation algorithms for the min-max edge -coloring problem.
These algorithms are based on a \emph{Breadth First Search} (BFS)-based
heuristic and on \emph{local search} methods like basic \emph{hill climbing},
\emph{simulated annealing} and \emph{tabu search} techniques, respectively.
Although several algorithms for particular graph classes were proposed by
Larjomaa and Popa (e.g., trees, planar graphs, cliques, bi-cliques,
hypergraphs), we design the first algorithms for general graphs.
We study and compare the running data for all algorithms on Unit Disk Graphs,
as well as some graphs from the DIMACS vertex coloring benchmark dataset.Comment: This is a post-peer-review, pre-copyedit version of an article
published in International Computing and Combinatorics Conference
(COCOON'18). The final authenticated version is available online at:
http://www.doi.org/10.1007/978-3-319-94776-1_5
Pulsed Generic Advertising: The Case of Common Property
Regulation of fisheries production together with public promotion of fisheries products offer a potentially profitable environment for fishermen. Yet production restrictions are usually insufficient to prevent entry, causing depletion of the resource base and dissipation of long-run profits from promotion. Shorter run gains may be possible, providing producer response to advertising is not instantaneous. Lagged biological and economic responses appear to provide a rationale for pulsed advertising. Moreover, a pulsed advertising policy is shown to mitigate the adverse effects on the resource base which would normally accompany expansion of consumption without direct production control.generic promotion, oysters, common property, pulsed advertising, Environmental Economics and Policy, Resource /Energy Economics and Policy,
Beach Zone Fish Community Structure In The James River, Virglnia
A seining survey of the fish fauna of the beach zone in the James River, Virginia, was conducted from July to December 1977. Weekly collections were made at 4 stations resulting in the capture of 17,602 individuals representing 36 species. Abundance and diversity were influenced by large catches of schooling and migratory species utilizing nearshore areas as a nursery ground. Freshwater species diversity peaked in August and September, while mesohaline species diversity peaked in July, September, and November. Cluster analysis was used to define 3 freshwater station groups representing warm, moderate, and cool water temperatures, but was not helpful in analyzing mesohaline stations.https://scholarworks.wm.edu/vimsbooks/1112/thumbnail.jp
Random on-board pixel sampling (ROPS) X-ray Camera
Recent advances in compressed sensing theory and algorithms offer new
possibilities for high-speed X-ray camera design. In many CMOS cameras, each
pixel has an independent on-board circuit that includes an amplifier, noise
rejection, signal shaper, an analog-to-digital converter (ADC), and optional
in-pixel storage. When X-ray images are sparse, i.e., when one of the following
cases is true: (a.) The number of pixels with true X-ray hits is much smaller
than the total number of pixels; (b.) The X-ray information is redundant; or
(c.) Some prior knowledge about the X-ray images exists, sparse sampling may be
allowed. Here we first illustrate the feasibility of random on-board pixel
sampling (ROPS) using an existing set of X-ray images, followed by a discussion
about signal to noise as a function of pixel size. Next, we describe a possible
circuit architecture to achieve random pixel access and in-pixel storage. The
combination of a multilayer architecture, sparse on-chip sampling, and
computational image techniques, is expected to facilitate the development and
applications of high-speed X-ray camera technology.Comment: 9 pages, 6 figures, Presented in 19th iWoRI
Tunable Double Negative Band Structure from Non-Magnetic Coated Rods
A system of periodic poly-disperse coated nano-rods is considered. Both the
coated nano-rods and host material are non-magnetic. The exterior nano-coating
has a frequency dependent dielectric constant and the rod has a high dielectric
constant. A negative effective magnetic permeability is generated near the Mie
resonances of the rods while the coating generates a negative permittivity
through a field resonance controlled by the plasma frequency of the coating and
the geometry of the crystal. The explicit band structure for the system is
calculated in the sub-wavelength limit. Tunable pass bands exhibiting negative
group velocity are generated and correspond to simultaneously negative
effective dielectric permittivity and magnetic permeability. These can be
explicitly controlled by adjusting the distance between rods, the coating
thickness, and rod diameters
Bond-Propagation Algorithm for Thermodynamic Functions in General 2D Ising Models
Recently, we developed and implemented the bond propagation algorithm for
calculating the partition function and correlation functions of random bond
Ising models in two dimensions. The algorithm is the fastest available for
calculating these quantities near the percolation threshold. In this paper, we
show how to extend the bond propagation algorithm to directly calculate
thermodynamic functions by applying the algorithm to derivatives of the
partition function, and we derive explicit expressions for this transformation.
We also discuss variations of the original bond propagation procedure within
the larger context of Y-Delta-Y-reducibility and discuss the relation of this
class of algorithm to other algorithms developed for Ising systems. We conclude
with a discussion on the outlook for applying similar algorithms to other
models.Comment: 12 pages, 10 figures; submitte
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