Exploitation of Multiple Stocks by a Common Fishery

1967 ◽  
Vol 24 (12) ◽  
pp. 2527-2537 ◽  
Author(s):  
G. J. Paulik ◽  
A. S. Hourston ◽  
P. A. Larkin
Keyword(s):  
Analytical Solution ◽  
Computer Program ◽  
Pacific Salmon ◽  
Reproduction Curve ◽  
Fishing Strategies ◽  
The Common ◽  
Sustained Yield

A complete analytical solution is presented for the problem of finding the common rate of exploitation that maximizes total sustained yield from a mixture of stocks when each stock follows a Ricker reproduction curve. A computer program is described which solves this problem for up to 20 stocks varying in both reproductive potentials and absolute sizes. Some aspects of the management of Pacific salmon and fishing strategies are discussed in relation to the question of obtaining maximum yields when harvesting mixtures of stocks under various constraints.

scholarly journals ANALYTICAL SOLUTION OF THE FREQUENCY OF THE LOAD OSCILLATION AT AN ARBITRARY GIRDER NODE IN THE SYSTEM MAPLE

2019 ◽  
pp. 3-3
Author(s):  
Mikhail N. Kirsanov ◽  
Dmitriy V. Tinkov
Keyword(s):  
Analytical Solution ◽  
Arbitrary Number ◽  
Analytical Form ◽  
Labor Costs ◽  
Induction Method ◽  
Regular Type ◽  
Final Formula ◽  
The Common ◽  
Two Stages ◽  
Elastic Lattice

Introduction. We study the oscillations of a massive load on a planar statically definable symmetric truss of a regular type with parallel belts. Truss weight is not included. Free vertical oscillations are considered. The stiffness of the truss rods is assumed to be the same, the deformations are elastic. Lattice of the truss is double with descending braces and racks. New in the formulation and solution of the problem is the analytical form of the solution, which makes it possible in practice to easily evaluate the frequency characteristics of the structure depending on an arbitrary number of truss panels and the location of the load. Materials and methods. The operators and methods of the system of computer mathematics Maple are used. To determine the forces in the rods, the knotting method is used. The common terms of the sequence of coefficients of solutions for different numbers of panels are obtained from solving linear homogeneous recurrent equations of various order, obtained by special operators of the Maple system. Dependence on two arbitrary natural parameters is revealed in two stages. First, solutions for fixed load positions are found, then these solutions are summarized into one final formula for frequency. Results. By a series of individual solutions to the problem of load oscillation using the double induction method, it was possible to find common members of all sequences. The solution is polynomial in both natural parameters. Graphs constructed for particular cases, showed the adequacy of the approach. The discontinuous non-monotonic nature of the intermittent change depending on the number of truss panels and some other features of the solution are noted. Conclusions. It is shown that the induction method, previously applicable mainly to statics problems with one parameter (number of truss panels), is fully operational to the problems of the oscillations of system with two natural parameters. It should be noted that significant labor costs and a significant increase in the time symbolic transformations in such tasks

Article 23—Common Provisions

2021 ◽  
pp. 408-408
Author(s):  
Eleonora Rosati
Keyword(s):  
Computer Program ◽  
Dispute Resolution ◽  
Alternative Dispute Resolution ◽  
Legal Protection ◽  
Computer Programs ◽  
Member States ◽  
Adjustment Mechanism ◽  
The Common ◽  
The Right

This chapter covers the common provisions in Article 23 of the copyright order in Europe, Directive 2019/790. It refers to Member States that are required to ensure that any contractual provision that prevents compliance with the transparency obligation and contract adjustment mechanism will be unenforceable in relation to authors and performers. It also looks at the legislation that causes non-compliance with the alternative dispute resolution procedure. The chapter points out that the provisions on the right of revocation do not apply to authors of a computer program within the meaning of Article 2 of Directive 2009/24/EC on the legal protection of computer programs. It emphasizes that the principle of appropriate and proportionate remuneration in Article 18 of Directive 2019/790 do not affect individuals involved in computer programs.

RATIONAL RADIAL DISTORTION MODELS OF CAMERA LENSES WITH ANALYTICAL SOLUTION FOR DISTORTION CORRECTION

2004 ◽  
Vol 01 (02) ◽  
pp. 135-147 ◽  
Author(s):  
LILI MA ◽  
YANGQUAN CHEN ◽  
KEVIN L. MOORE
Keyword(s):  
Analytical Solution ◽  
Polynomial Approximation ◽  
Distortion Correction ◽  
Camera Model ◽  
Distortion Model ◽  
Radial Distortion ◽  
New Class ◽  
Comparable Accuracy ◽  
The Common ◽  
Distortion Parameters

The common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires estimation of these distortion parameters. The task of estimating radial distortion is to find a radial distortion model that allows easy undistortion as well as satisfactory accuracy. This paper presents a new class of rational radial distortion models with easy analytical undistortion formulae. Experimental results are presented to show that with this class of rational radial distortion models, satisfactory and comparable accuracy can be achieved.

Predation of Juvenile Pacific Salmon by the Common Merganser (Mergus merganser) on Eastern Vancouver Island. II: Predation of Stream-Resident Juvenile Salmon by Merganser Broods

1987 ◽  
Vol 44 (5) ◽  
pp. 950-959 ◽  
Author(s):  
C. C. Wood
Keyword(s):  
Body Weight ◽  
Census Data ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Vancouver Island ◽  
Juvenile Salmonids ◽  
Mergus Merganser ◽  
The Common ◽  
Tidal Waters ◽  
Common Merganser

Predation of stream-resident juvenile salmonids by broods of the common merganser (Mergus merganser) was investigated in three streams on eastern Vancouver Island from 1980 to 1982. Daily fish consumption by merganser ducklings was estimated to range from 80% of body weight for ducklings at 10 d of age to 40% of body weight for those at 40 d of age. Merganser ducklings were never observed to eat juvenile salmonids on tidal waters, but did eat them on the freshwater reaches of streams studied. Typically, broods inhabited only the freshwater reaches of their natal stream while young, but spent progressively more time foraging on tidal waters as they grew older. The biomass of broods (and hence potential consumption) on fresh water was estimated by reconstructing the history of individual broods from census data. These results suggest that merganser broods consumed on the order of 82 000–131 000 coho salmon (Oncorhynchus kisutch) fry in the Big Qualicum River between June 10 and August 25. This is equivalent to 24–65% of the observed wild smolt production from this system, assuming that these fry would otherwise have survived as well as uneaten fry.

An Analytical Solution for Stress and Displacement in Casing-Cement Combined Cylinder under Non-Uniform Loading

2011 ◽  
Vol 291-294 ◽  
pp. 2133-2138 ◽  
Author(s):  
Mu Hui Fan ◽  
Yong Shu Jiao ◽  
Zong Xi Cai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Analytical Solution ◽  
Computer Program ◽  
Theory Of Elasticity ◽  
Composite Cylinder ◽  
The Finite Element Method ◽  
Uniform Loading ◽  
Cement Sheath ◽  
Good Agreement

Based on the theory of elasticity and taken the casing-cement sheath as a totally contacted composite cylinder subjected to arbitrarily distributed loading on inner and outer surfaces, an analytical solution in Fourier serial form was obtained for stresses and displacements. A computer program was developed to evaluate the stress and displacement in the combined cylinder. The results are in good agreement with those from the finite element method (FEM). With these solutions we can investigate the interaction between casing and the cement sheath. This is of importance in improving the design of casing.

scholarly journals LIMIT DISTRIBUTIONS OF SOME STEREOLOGICAL ESTIMATORS IN WICKSELL'S CORPUSCLE PROBLEM

2011 ◽  
Vol 26 (2) ◽  
pp. 63 ◽  
Author(s):  
Lothar Heinrich
Keyword(s):  
Analytical Solution ◽  
Asymptotic Behaviour ◽  
Point Process ◽  
Cross Section ◽  
Homogeneous System ◽  
Spherical Particles ◽  
Limit Distributions ◽  
The Common ◽  
Special Case ◽  
Independent Identically Distributed

Suppose that a homogeneous system of spherical particles (d-spheres) with independent identically distributed radii is contained in some opaque d-dimensional body, and one is interested to estimate the common radius distribution. The only information one can get is by making a cross-section of that body with an s-flat (1 ≤ s ≤ d -1) and measuring the radii of the s-spheres and their midpoints. The analytical solution of (the hyper-stereological version of) Wicksell's corpuscle problem is used to construct an empirical radius distribution of the d-spheres. In this paper we study the asymptotic behaviour of this empirical radius distribution for s = d -1 and s = d - 2 under the assumption that the s-dimensional intersection volume becomes unboundedly large and the point process of the midpoints of the d-spheres is Brillinger-mixing. Of course, in stereological practice the only relevant cases are d = 3; s = 2 or s = 1 and d = 2; s = 1. Among others we generalize and extend some results obtained in Franklin (1981) and Groeneboom and Jongbloed (1995) under the Poisson assumption for the special case d = 3; s = 2.

scholarly journals A UNIFIED ANALYTICAL SOLUTION FOR WAVE SCATTERING BY RECTANGULAR-SHAPED OBJECTS

2018 ◽  
pp. 7
Author(s):  
Jie Hu ◽  
Philip Li-Fan Liu
Keyword(s):  
Analytical Solution ◽  
General Solution ◽  
General Theory ◽  
Computer Program ◽  
Rectangular Plate ◽  
Analytical Solutions ◽  
Wave Scattering ◽  
Submerged Plate ◽  
Floating Breakwater ◽  
Stationary Objects

This paper presents a general solution for wave scattering by stationary objects, which consist of a submerged rectangular plate and a floating rectangular dock. The objects can be either permeable or solid. The general solution is capable to cover all the existing single rectangular objects, such as a surface-piercing breakwater, a bottom-mounted submerge breakwater and a submerged plate. Furthermore, this general solution can also yield new analytical solutions for different combinations of objects, i.e. a single floating breakwater, and a combination of a floating and a bottom-mounted breakwater. Based on the general theory, a MATLAB computer program has been developed. It can be used to further explore different breakwater configurations with different properties.

scholarly journals SPECTRUM OF OWN FREQUENCIES OF A SPATIAL SURFACING GIRDER

2021 ◽  
pp. 104-113
Author(s):  
M. N. Kirsanov
Keyword(s):  
Analytical Solution ◽  
Spatial Structure ◽  
Lower Estimate ◽  
Optimization Problems ◽  
Natural Oscillations ◽  
Analytical Estimate ◽  
Rod Cells ◽  
Mass Size ◽  
The Common ◽  
Oscillation Frequencies

Statement of the problem. The scheme of a statically definable girder of a spatial rectangular surfacing is discussed. The problem is to identify the formula for the dependence of the lower estimate of the first frequency of the natural oscillations of the structure by means of the Donkerley method on the number of panels. The truss has supports on the sides and consists of separate rod cells connected in pyramids. Results. Based on the analysis of the sequence of analytical solutions for the first frequency of girders with a different number of panels by induction, the coefficients in the desired formula are derived. The common members of the sequences of coefficients are found as solutions of homogeneous recurrent equations formed according to the results of the calculations using Maple operators. The resulting dependences are obtained in the form of polynomials by the number of panels. A comparison of the analytical solution with the numerical one is provided.Conclusions. An algorithm for deriving an analytical estimate of the fundamental frequency of oscillations of a spatial structure depending on the number of panels, mass, size, and elastic properties of the material is shown. The spectrum of oscillation frequencies of the structure is analyzed. The resulting dependences can be employed in seismic and structural optimization problems.

scholarly journals Analytical solution of the longitudinal wave propagation due to the single impact

2018 ◽  
Vol 37 (4) ◽  
pp. 849-858
Author(s):  
M Akhondizadeh
Keyword(s):  
Wave Propagation ◽  
Analytical Solution ◽  
Longitudinal Wave ◽  
Impact Force ◽  
Initial Condition ◽  
Simple Assumption ◽  
Longitudinal Wave Propagation ◽  
The Common ◽  
The Impact ◽  
Sinusoidal Function

In the present work, the rod response due to the impact of a ball is studied in order to analyze the longitudinal wave propagation during the impact and evaluate the velocity of points over the rod length at the end of impact. An analytical solution is given for the governing equation of rod vibration by assuming the impact force as an equivalent sinusoidal function of time. The impact force is defined by a Fourier series to be zero at the rod length except at the impacted end. An analysis of wave propagation will give information about the rod–ball interaction. The evaluated velocity profile at the end of impact can be used as the initial condition for after-impact solution of the rod vibration. It will modify the common simple assumption of constant initial velocity for impacted end.

Sign in / Sign up

Export Citation Format

Share Document