Increment—Decrement Life Tables: Some Further Comments from a Demographic-Accounting Point of View

1978 ◽  
Vol 10 (6) ◽  
pp. 705-726
Author(s):  
P H Rees
Keyword(s):  
Life Table ◽  
Theoretical Investigation ◽  
Life Tables ◽  
Point Of View ◽  
Alternative Methods ◽  
Test Case ◽  
Alternative Method

The paper examines the problem of the estimation of the correct probabilities needed as input to a multiregional life table. A variety of alternative methods are examined by use of an expanded notation and a hypothetical test case. This theoretical investigation suggests that methods proposed by previous researchers are in error and an alternative method is proposed. However, this error is likely to be small in cases where the probabilities of transition from one region to another are small.

scholarly journals Solving Abel’s Type Integral Equation with Mikusinski’s Operator of Fractional Order

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Ming Li ◽  
Wei Zhao
Keyword(s):  
Integral Equation ◽  
Fractional Order ◽  
Operational Calculus ◽  
Point Of View ◽  
Alternative Method ◽  
Type Integral

This paper gives a novel explanation of the integral equation of Abel’s type from the point of view of Mikusinski’s operational calculus. The concept of the inverse of Mikusinski’s operator of fractional order is introduced for constructing a representation of the solution to the integral equation of Abel’s type. The proof of the existence of the inverse of the fractional Mikusinski operator is presented, providing an alternative method of treating the integral equation of Abel’s type.

scholarly journals Orędzie biskupów polskich w ocenie niemieckiego MSZ

2011 ◽  
pp. 73-91
Author(s):  
Piotr Madajczyk
Keyword(s):  
Domestic Politics ◽  
Point Of View ◽  
West Germany ◽  
Alternative Methods ◽  
Political Climate ◽  
History Of

The history of the Polish Bishops’ Letter of Reconciliation to the German bishops, sent in the autumn of 1965, that is, in a very inopportune political climate, is now relatively well known and researched. What contributed to its being widespread, was the perception of it as a pre-cursor of the Polish-German reconciliation, an initiative which, while not capable of having a real impact on Poland and West Germany in the 60s, pointed to alternative methods by which it could be carried out and distanced itself from retaining hostility as a basis for Polish-German relations and using the stereotype of a threat on the part of Germany in Polish domestic politics. The circumstances in which the Letter had been brought into being could be studied thanks to the opening of Polish archives after the fall of Communism. The article shows how the Letter was received by West German diplomacy, in terms, most of all, of an appraisal of the chances and opportunities in the international arena which could follow from such a reception. What was important from Bonn’s point of view was the setting of the controversies around the Letter in Poland in a wider context, namely, one of balancing the relationships between determinants rooted in domestic politics, the policy of Moscow and the East Block and that of the Vatican.

scholarly journals Data granularity in mid-year life table construction

2020 ◽  
Author(s):  
Jose M Pavia ◽  
Natalia Salazar ◽  
Josep Lledo
Keyword(s):  
Big Data ◽  
Life Table ◽  
Death Rate ◽  
Life Tables ◽  
Population Estimates ◽  
Substantial Influence ◽  
Pension Systems ◽  
Insurance Policies ◽  
Statistical Agencies ◽  
Data Granularity

Life tables have a substantial influence on both public pension systems andlife insurance policies. National statistical agencies construct life tables fromhypotheses death rate estimates to the (mx aggregated ), or death figures probabilities of demographic (q x ), after applying events (deaths, variousmigrations and births). The use of big data has become extensive acrossmany disciplines, including population statistics. We take advantage of thisfact to create new (more unrestricted) mortality estimators within the familyof period-based estimators, in particular, when the exposed-to-riskpopulation is computed through mid-year population estimates. We useactual data of the Spanish population to explore, by exploiting the detailedmicrodata of births, deaths and migrations (in total, more than 186 milliondemographic events), the effects that different assumptions have oncalculating death probabilities. We also analyse their impact on a sample ofinsurance product. Our results reveal the need to include granular data,including the exact birthdate of each person, when computing period mid-year life tables.

A Novel Method of Coupling the Steam Turbine Exhaust Hood and the Last Stage Blades Using the Non-Linear Harmonic Method

2013 ◽  
Author(s):  
Zoe Burton ◽  
Grant Ingram ◽  
Simon Hogg
Keyword(s):  
Steam Turbine ◽  
Turbine Blades ◽  
Computation Time ◽  
Computational Effort ◽  
Alternative Methods ◽  
Test Case ◽  
Exhaust Hood ◽  
Harmonic Method ◽  
Non Linear ◽  
Last Stage

The exhaust hood of a steam turbine is a vital area of turbomachinery research its performance strongly influences the power output of the last stage blades. It is well known that accurate CFD simulations are only achieved when the last stage blades are coupled to the exhaust hood to capture the strong interaction. This however presents challenges as the calculation size grows rapidly when the full annulus is calculated. The size of the simulation means researchers are constantly searching of methods to reduce the computational effort without compromising solution accuracy. This work uses a novel approach, by coupling the last stage blades and exhaust hood by the Non-Linear Harmonic Method, a technique widely used to reduce calculation size in high pressure turbine blades and axial compressors. This has been benchmarked against the widely adopted Mixing Plane method. The test case used is the Generic Geometry, a representative exhaust hood and last stage blade geometry that is free from confidentiality and IP restrictions and for which first calculations were presented at last year’s conference [1]. The results show that the non-uniform exhaust hood inlet flow can be captured using the non-liner harmonic method, an effect not previously achievable with single passage coupled calculations such as the mixing plane approach. This offers a significant computational saving, estimated to be a quarter of the computation time compared with alternative methods of capturing the asymmetry with full annulus frozen rotor calculations.

Modeling Partial Admission in Control Stages of Small Steam Turbines With CFD

2018 ◽  
Author(s):  
Juri Bellucci ◽  
Filippo Rubechini ◽  
Andrea Arnone
Keyword(s):  
Steam Turbine ◽  
Three Dimensional ◽  
Admission Rate ◽  
Point Of View ◽  
Test Case ◽  
Steam Turbines ◽  
Turbine Stage ◽  
Performance Curves ◽  
Partial Admission ◽  
The Impact

This work aims at investigating the impact of partial admission on a steam turbine stage, focusing on the aerodynamic performance and the mechanical behavior. The partialized stage of a small steam turbine was chosen as test case. A block of nozzles was glued in a single “thick nozzle” in order to mimic the effect of a partial admission arc. Numerical analyses in full and in partial admission cases were carried out by means of three-dimensional, viscous, unsteady simulations. Several cases were tested by varying the admission rate, that is the length of the partial arc, and the number of active sectors of the wheel. The goal was to study the effect of partial admission conditions on the stage operation, and, in particular on the shape of stage performance curves as well as on the forces acting on bucket row. First of all, a comparison between the flow field of the full and the partial admission case is presented, in order to point out the main aspects related to the presence of a partial arc. Then, from an aerodynamic point of view, a detailed discussion of the modifications of unsteady rows interaction (potential, shock/wake), and how these ones propagate downstream, is provided. The attention is focused on the phenomena experienced in the filling/emptying region, which represent an important source of aerodynamic losses. The results try to deepen the understanding in the loss mechanisms involved in this type of stage. Finally, some mechanical aspects are addressed, and the effects on bucket loading and on aeromechanical forcing are investigated.

Gaseous Solutions

1993 ◽  
Author(s):  
Greg M. Anderson ◽  
David A. Crerar
Keyword(s):  
Equations Of State ◽  
Intermolecular Forces ◽  
Point Of View ◽  
Alternative Methods ◽  
Gaseous Species ◽  
Fugacity Coefficient ◽  
Ideal Gases ◽  
Component Systems ◽  
Liquid Solutions ◽  
History Of

The procedures described in Chapter 15 are well suited to solid and liquid solutions and could also be applied to gases, but in fact, other approaches are generally used. The main reason for this is partly historical; much work was done early in the history of physical chemistry on the behavior of gases, and these methods have continued to evolve to the present day. We have also just seen that the Margules equations become very unwieldy with multi-component systems. Because true gases are completely miscible, natural gases often contain many different components, so the Margules approach is not very suitable. Unfortunately, the most successful alternative methods described in this section are also quite unwieldy; however, they do not become much more complicated for multi-component gases than they are for the pure gases themselves, and this is a definite advantage. We have seen that with real, non-ideal gases, all the thermodynamic properties are described if we know the T, P, and the fugacity coefficient. For gaseous solutions, the fugacity coefficient for each component generally depends on the concentrations and types of other gaseous species in the same mixture. All gases, whether pure or multi-component, should approach ideality at higher T and lower P; conversely, non-ideality is most pronounced in dense, low-temperature gases where intermolecular forces are strongest. The challenge here is to find an equation of state that can adequately cover this range of conditions for gases of many different constituents. In the following discussion we first briefly outline some of the equations of state used to describe pure gases. We will introduce these from the molecular point of view since this helps understand the physical basis (and limitations) of each model. Each of these equations of state can then be applied to mixtures of gases using a set of rules which we describe at the end of this section.

On the possible Methods of Dividing the Net Profits of a Mutual Life Assurance Company amongst the Members

1856 ◽  
Vol 6 (5) ◽  
pp. 278-287
Author(s):  
Henry Wilbraham
Keyword(s):  
Life Table ◽  
Sole Source ◽  
Life Tables ◽  
Present Value ◽  
Fixed Amount ◽  
Life Assurance ◽  
Different Ages ◽  
A Charge ◽  
Additional Charge ◽  
Stationary Period

The object of this paper is to give a brief exposition of the different possible methods or classes of methods of equitably dividing the net profits of a Mutual Life Assurance Office among the members. By an equitable division must be understood one which is fair not only between persons of different ages entering the Office at the same time, but also between persons entering the Office at different epochs of its existence,–one from which the members of different ages will, relatively to one another, receive the same benefit from the profits during the earlier and growing years of the Office, and during years when the amount of its business is declining, as during its stationary period. I assume the premiums actually paid to be composed of the net premium calculated from a correct life table, and of a charge of 25 per cent. on the net premium added to guard against unfavourable contingencies, and that this additional charge is really the source of all the profit divisible among the members; or at least, that whatever profits arise from any other source may be fairly apportioned in the same proportions as appear equitable on the supposition that the charge is the sole source of profits. The addition to the premiums for defraying the expenses of the Office, for the sake of simplicity, I leave out of account. In consideration of the payments of the successive net premiums, the assured is guaranteed a sum at death such that the present prospective value of that sum is equal to the present value of the successive net premiums. Similarly, in consideration of the successive charges on the premiums, he should have the prospect of receiving a sum or sums either at death or at any times before that; not guaranteed, it is true, to any fixed amount, but variable with the circumstances of the Society, such that the present value of such sums or bonuses shall be equal to the present value of the successive charges. That this equation between the present values ought to subsist is as clear in the case of the charges and bonuses as in that of the net premiums and sums assured. If the system of division of profits be such that this equation always subsist, it must be fair as respects each member; and any Office adopting a system in which it does not subsist is committing as great an injustice towards its members as one which calculates the premiums on false life tables.

Tri-Generation Systems Optimization: Comparison of Heuristic and Mixed Integer Linear Programming Approaches

2014 ◽  
Author(s):  
Aldo Bischi ◽  
Stefano Campanari ◽  
Alberto Castiglioni ◽  
Giampaolo Manzolini ◽  
Emanuele Martelli ◽  
...  
Keyword(s):  
Linear Programming ◽  
Integer Linear Programming ◽  
Mixed Integer Linear Programming ◽  
Storage System ◽  
Simulation Models ◽  
Point Of View ◽  
Mixed Integer ◽  
Test Case ◽  
Optimization Strategy ◽  
Software Codes

This work compares two optimization approaches for combined cooling, heating and power (CCHP or Tri-generation) energy systems scheduling. Both approaches are developed through dedicated software codes and are based on simulation models capable of evaluating of the best operating strategy (both economically and energy-wise) to run a given trigeneration plant while dealing with time-variable loads and tariffs. The simultaneous use of different prime movers operating in parallel is taken into consideration as well as their part load performance, the influence of ambient temperature and the usage of a heat storage system. Cooling may be generated through absorption chillers or electrically driven compression cycles. One of the models is heuristic and adopts an optimization strategy based on a multi-step approach: it simulates several cases according to a pre-defined number of paths, exploring the most reasonable operational modes and comparing them systematically. The other relies on a mathematical approach, based on a Mixed Integer Linear Programming (MILP) optimization model which has been developed in order to deal with more complex systems without the need of predefining a too large variety of operation paths. Results of the two models are compared against a test case based on real plant specifications, discussing their performance by the point of view of simulation capabilities, quality and accuracy of the optimization results (in terms of differences in energy and economic performance) and computational resources.

An Euler Solution for Unsteady Flows Around Oscillating Blades

1990 ◽  
Vol 112 (4) ◽  
pp. 714-722 ◽  
Author(s):  
L. He
Keyword(s):  
Unsteady Flows ◽  
Nonlinear Behavior ◽  
Alternative Methods ◽  
Finite Volume Scheme ◽  
Test Case ◽  
System A ◽  
Standard Configuration ◽  
Time Marching ◽  
Grid Technique ◽  
Euler Solution

A time-marching Euler calculation for 2-D and quasi-3-D unsteady flows in oscillating blade rows is presented, based on a finite volume scheme with cell-vertex discretization in space and 2-step Runge-Kutta integration in time. Extra fluxes due to the deformation of the moving finite volumes are directly included in the conservation equations in the physical coordinate system. A zonal moving grid technique is used, in which only subregions near oscillating blades are moved to fit both the moving (blade) boundaries and fixed regions. For phase-shifted periodic conditions, the conventional “Direct Store” method is used as a basis for comparison. Two alternative methods to save computer storage are proposed and preliminary demonstrations of their usefulness are given in the present calculations. Calculated results for unsteady flows in an oscillating flat plate cascade are in good agreement with those from two well-established linear methods, LINSUB and FINEL. The unsteady pressure distribution and aerodynamic damping calculated by the present method for a turbine blade test case (Aeroelasticity Workshop Standard Configuration No. 4 cascade) agree well with the corresponding experimental data. Computations for an oscillating biconvex cascade in transonic flow conditions are performed, which show some strong nonlinear behavior of shock wave movement.

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