bluuebunny/crossref_metadata_2025_split huggingface dataset:
Individual Risk Theory and Risk Statistics as Applied to Fire Insurance
Authors: Almer Bertil 
Published: July 2016

Risk Theory for Life Insurance is simplified by the fact that the distribution Ψ (x) of claim amounts x approximately coincides with the distribution of “Risk sums” (not exactly, owing to differaences in the claim frequency with age and actual state of health), ond this distribution is comparatively stable.—The dependence on the claim frequency is eliminated by the introduction of a new time variable, and the system reduced to a (stationary) Poisson Process, which should be valid at least for large risk systems and for the total Life branch for a moderate sequence of years.In almost all non-life branches, partial claims will dominate and Ψ (x) can only be determined by risk statistics, leaving a certain space of indetermination, in particular for large claims and for mediumsized statistical risk groups.In my previous analyses, in particular New York 1957, interest has been concentrated on traffic and motor car insurance, where the risk depends on cars insured and on the meeting traffic (including road conditions). In one year the same car can be involved in many accidents and double claims (=collisions) are rather frequent.—According to my experience, this system is best represented by a sequence of single and double risk situations in time (for individual cars or for risk groups).Analysis is simplified for Fire Insurance (and many other non-life branches), because the risk system is composed of mostly independent insurances (or risk objects), which are best described by the ordinary Individual Risk Theory.
A Remark on the Principle of Zero Utility
Authors: Gerber Hans U. 
Published: July 2016

Let u(x) be a utility function, i.e., a function with u′(x)>0, u″(x)<0 for all x. If S is a risk to be insured (a random variable), the premium P = P(x) is obtained as the solution of the equationwhich is the condition that the premium is fair in terms of utility. It is clear that an affine transformation of u generates the same principle of premium calculation. To avoid this ambiguity, one can standardize the utility function in the sense thatfor an arbitrarily chosen point y. Alternatively, one can consider the risk aversionwhich is the same for all affine transformations of a utility function.Given the risk aversion r(x), the standardized utility function can be retrieved from the formulaIt is easily verified that this expression satisfies (2) and (3).The following lemma states that the greater the risk aversion the greater the premium, a result that does not surprise.
Actuarial Remarks on Planning and Controlling in Reinsurance
Authors: Straub Erwin 
Published: July 2016

Planning is, or ought to be, an ever-developing process in which virtually each member of the company has to be involved. Planning without controlling, i.e., without feedback, planning on its own, is useless.In the first part of the present note, general aspects of planning are briefly described inasfar as they are relevant to possible treatment by actuarial methods.The circles in the above figure represent what could be called the hardware of planning consisting of three sets of figures, namely• Actual figures describing the most recent reality. Most of these figures are part of what is usually called the Earnings Statement (EST).• Forecasts for the near future, say the next three years. Most of these figures are contained in the Planning Budget (PLB).• Control figures or signals in the sense of a “bread-line” expressing, for example, how much the company should earn as a minimum in order to remain self-financing. Such figures are calculated on the basis of so-called Return on Equity considerations and they are found in a corresponding ROE-document.By software we mean everything done with the hardware described above, i.e., primarily the comparison of figures from different domains of the hardware on different levels within the organisation of the company, the analysis, for example, of deviations between actual and planned, the conclusions to be taken from such analyses and the planning of new actions as a consequence.In the above graph, circles symbolize the hardware and arrows indicate the software.Also non-numeric planning instruments (e.g., project planning, action plans, assessment and decisions) are considered to be part of the planning software.
Une classe des processus de risque et leur algorithme de resolution
Authors: Franckx Ed. 
Published: July 2016

A l'encontre de la théorie classique de l'assurance collective, qui s'intéresse plus particulièrement aux problèmes asymptotiques, les praticiens de l'assurance „non life” et les autorités de contrôle souhaitent disposer d'une méthode effective de calcul permettant de chiffrer la valeur réelle des probabilités de ruine dans un avenir plus ou moins rapproché.Telle fut la remarque de notre collègue Bichsel au colloque d'ASTIN en 1967 à Arnhem. Dans le bulletin des Actuaires Suisses nous avons publié deux notes sur „une théorie opérationnelle du risque”. A la base se trouve l'emploi des processus markoviens discrets. Ces études prolongeaient un premier essai, exposé à l'Université de Trieste en 1963; une conférence donnée à Tel Aviv en 1967 développait le même thème. Dans un autre domaine, celui de la Recherche Opérationnelle, les ingénieurs utilisent depuis longtemps les mêmes processus de Markov pour étudier, par la dynamique stochastique, l'évolution d'un système aléatoire.
On Additive Premium Calculation Principles
Authors: Gerber Hans U. 
Published: July 2016

A premium calculation principle is a general rule that assigns a premium P to any given risk S. Intuitively, P is what the insurance carrier charges (apart from an expense allowance) for taking over the risk S (see [3], p. 85-87). Mathematically, S is a random variable, and P depends on S through its distribution function. The value of P may be finite or infinite; in the latter case we speak of an uninsurable risk.A premium calculation principle is called additive, if the premium assigned to the sum of two independent risks is the sum of the premiums that are assigned to the two risks individually. For example, the variance principle, P = E[S] + β Var [S] (β > o), is additive, because the variance of the sum of independent random variables equals the sum of the variances. Additivity is a very desirable property, from a theoretical as well as from a practical point of view (as pointed out by Borch [2], p. 429).The variance principle is not entirely satisfactory for various reasons. For one thing it does not take account of the skewness of S (a risk whose distribution is skewed to the right seems to be more dangerous than one with a symmetrical distribution). Furthermore, it produces in some cases a premium P that exceeds S with probability one (example: β = .3, S = o or 10, each with probability 1/2).
Some Transient Results on the M/SM/1 Special Semi-Markov Model in Risk and Queueing Theories
Authors: Janssen Jacques 
Published: July 2016

We consider a usual situation in risk theory for which the arrival process is a Poisson process and the claim process a positive (J — X) process inducing a semi-Markov process. The equivalent in queueing theory is the M/SM/1 model introduced for the first time by Neuts (1966).For both models, we give an explicit expression of the probability of non-ruin on [o, t] starting with u as initial reserve and of the waiting time distribution of the last customer arrived before t. “Explicit expression” means in terms of the matrix of the aggregate claims distributions.
The Solvency Margin in Non-Life Insurance Companies
Authors: de Wit G. W. , Kastelijn W. M. 
Published: July 2016

Much attention has been paid in the last ten years to the necessary solvency margin especially as influenced by risk theory considerations. In these calculations, by which the solvency margin is determined in such a way that the probability of ruin remains under a specified norm, such factors as type of insurance, size of portfolio, reinsurance etc. play an essential role.In these calculations, based on pure risk theory, there is thus no attention paid to risks in the investment field, in the area of costs, etc. Yet one must not forget that the solvency margin must also act as a buffer against these uncertainties, in other words the solvency margin must be large enough to cover all risks to which the concern is liable, within stipulated limits of certainty.One drawback of a pure risk theoretical approach, as interpreted above, is that the bases of the risk theory are often difficult to translate into practical terms, and furthermore will differ from company to company. The latter is also the case with the size of portfolio, reinsurance, etc. However, if this could all be translated into practical terms in the right way, the results would upset relations between competitors, so that it seems natural to make the required solvency margin the same for all companies.Seen in this light Campagne's approach is of great importance—already in 1948 he realized that a scientific basis for the size of the solvency margin was necessary. He confined himself to the life insurance industry, and based his calculations on the idea that the total results of the companies working in a country should be such that, ceteris paribus, the chance of bankruptcy remains below a stipulated norm.
A Characterization of the Esscher-Transformation
Authors: Kremer Erhard 
Published: July 2016

One of the central problems in risk theory is the calculation of the distribution function F of aggregate claims of a portfolio. Whereas formerly mainly approximation methods could be used, nowadays the increased speed of the computers allows application of iterative methods of numerical mathematics (see Bertram (1981), Küpper (1971) and Strauss (1976)). Nevertheless some of the classical approximation methods are still of some interest, especially a method developed by Esscher (1932).The idea of this so called Esscher-approximation (see Esscher (1932), Grandell and Widaeus (1969) and Gerber (1980)) is rather simple:In order to calculate 1 –F(x) for large x one transforms F into a distribution function such that the mean value of is equal to x and applies the Edgeworth expansion to the density of The reason for applying the transformation is the fact that the Edgeworth expansion produces good results for x near the mean value, but poor results in the tail (compare also Daniels (1954)).
The Lognormal Model for the Distribution of one Claim
Authors: Benckert Lars-Gunnar 
Published: July 2016

The most important property of a distribution function to be used as a model for the distribution of one claim is of course that it fits the data well enough. If there is no natural truncation point in the data a more formal demand is that all the moments of the distribution function exist. Further, to be of a real value to the statistician, the chosen d.f. ought to be reasonably handy to use. As all the moments of the lognormal d.f. exist the first point to be checked is whether the lognormal d.f. fits the data. The other points on the list below are the qualities that I think are of the greatest value when using a distribution function, i.e. they reflect the handiness of the d.f.Does the lognormal d.f.1. Fit the data?2. Give an unbiased and efficient estimate of the mean? It is important that this estimate is not too difficult to compute.3. Give a practicable confidence interval of the mean?4. Give a known distribution function of the estimate of the risk premium?This paper is an attempt to give an affirmative answer to these questions. As the lognormal distribution function has been treated in the monograph “The lognormal distribution” by J. Aitchison and J. A. C. Brown (Cambridge University Press) the theory of this distribution function will not be dealt with more than necessary for the context.
Some Notes on the Statistical Theory of Extreme Values
Authors: Beard R. E. 
Published: July 2016

In preparing the notes on the subjects for discussion at the 4th ASTIN Colloquium at Trieste [1] I used some of the material which formed the basis of a talk given to the Scandinavian Actuarial Societies in September 1962. The papers presented in Trieste have established on a firm mathematical footing the formula for the excess loss premium derived in my note but the discussions also showed that some of the other 1962 material would be of interest.It will be appreciated that the question originally proposed, i.e. to calculate an excess of loss reinsurance premium when the only information available is the largest claim experienced in each of a succession of periods, was deliberately phrased in this form as being the most troublesome case likely to arise in practice. Clearly if other information is available it would not be rejected in arriving at a premium, but this immediately extends the problem to one of finding the best methods of combining information of different kinds. For example if, say, the largest 5 claims in each period are known, what technique will make the maximum use of the data? Such extensions of the problem are not discussed in this note. Furthermore, I am not unmindful of the valuable comment by Jung, “that there is a natural law which states that you can never get more out of a mincing machine than what you have put into it” [2].
A Theoretical Study of the No-Claim Bonus Problem
Authors: Derron Marcel 
Published: July 2016

The no-claim bonus problem has given rise to a considerable amount of discussion throughout the whole world. There is quite a difference of opinion among the actuaries and other experts concerned in this field and several exchanges of view have taken place the last few years. The ASTIN section of the Permanent Committee has been well aware of this fact and it has devoted one Colloquium to this subject and discussed it at others.In 1959 the major part of the La Baule meeting was dedicated to this subject and attention was focussed on this problem once again at Rattvik in 1961. Nevertheless controversies on this subject still continue. Almost every conference where the bonus problem is discussed is marked by a widespread difference of opinion.As is well known, the claim frequencies under insurance policies show a considerable heterogeneity, especially in the early years. It is not possible to get homogeneous sub-groups by means of a continuous subdivision; what may be gained in homogeneity, is lost in credibility. It seems therefore that a subsequent adjustment of premiums according to the past claim record may well be a suitable way of obtaining a fair premium.Those who are in favour of a rating procedure granting a bonus at a careful driver will stress that criticism is useless as long as no better solution is available, whereas actuaries who reject such a rating system argue that the unfairness of a flat rate is not at all eliminated by means of a bonus.
Statistical Models of Claim Distributions in Fire Insurance
Authors: Benckert Lars-Gunnar , Jung Jan 
Published: July 2016

SummaryThe authors have studied the combined data on claims in fire insurance of dwelling houses reported 1958-1969 by Swedish fire insurance companies The claims were cleared of deductibles and adjusted according to a suitable index Only losses above the largest deductible (in real value) applied during the observation period were included.The material contains four different classes according to the fire resistibillty of the building construction For international comparisons, the pure classes B1 (“stone” dwellings) and B4 (wooden houses) are of interest The distribution of the claims could be well approximated by the log-normal distribution in B1and by the Pareto distribution in B4 An equally good or better fit was obtained by assuming the original loss, reported or not, being distributed according to these distributions and applying the distributions, conditioned by the loss being larger than the deductible in both cases the distribution parameters are functions of the insurance amount in such a way, that the mean value of the loss is described as a power of this amount.The authors refrain from any theoretical arguments for the general applicability of the distributions used They observe, however, the good approximation by wellknown parametric distributions which facilitates many actuarial taks, such as the determination of first loss premiums, deductible premium factors, excess-of-loss premiums etc The agreement between model and reality make these functions fit for use in the models underlying the general risk theory and in the more comprehensive models of the non-life insurance business.
Contributions to the Theory of the Largest Claim Cover
Authors: Kupper J. 
Published: July 2016

In the wake of the technical development of our era we are increasingly faced with claims of extremely large amounts.Whereas even in the past century large claims were mostly due to elemental or natural forces such as earthquakes, hurricanes and floods, there are today other causes, conditioned by human factors, that have considerably increased in importance. Another fact to be observed is that the risks that are passed on to the insurance market assume a more serious character year by year. Large building complexes, giant tankers, containers, atomic power stations, dams and jumbo jets pose for the insurers problems which are in no way easy to solve, since the risk covers required touch the limits of market capacity and their rating is subject to great uncertainties. At the same time, the readiness to underwrite such covers is a matter of utmost importance for the private insurance industry.For the coverage of such large risks, various insurance forms have been developed in the past years within the range of non-proportional methods. Besides the excess of loss and stop loss covers in their usual form, the cumulative loss cover and the largest claim cover have attracted particular attention. The cumulative risk cover has, for example, been dealt with in [11]) and has also been frequently offered in practice. The coverage of the largest claim or, more generally, of the sum of the n largest claims does not appear to have gained a proper foothold in practice in spite of various valuable contributions in this field—considering particularly [2], [3], [5], [8] and [14]. The fact that it was during 1963/64 that various authors analysed these problems is no coincidence, for it was then that in two ASTIN Colloquia these topics were discussed.
Molecular characterization and antimicrobial resistance of STEC strains isolated from healthy cattle in 2011 and 2013 in Spain
Authors: CABAL A. , PORRERO M. C. , DE LA CRUZ M. L. , SAEZ J. L. , BARCENA C. , LOPEZ G. , GORTAZAR C. , DOMINGUEZ L. , ALVAREZ J. 
Published: July 2016

SUMMARYPrevention of Shiga toxin-producingEscherichia coli(STEC) foodborne outbreaks is hampered by its complex epidemiology. We assessed the distribution of virulence genes (VGs), main serogroups/serotypes for public health [haemolytic uraemic syndrome (HUS)-related], antimicrobial resistance (AMR) profiles and pulsed-field gel electrophoresis (PFGE) patterns in a collection of STEC isolates obtained from cattle hide (n= 149) and faecal (n= 406) samples collected during a national survey conducted in Spain in 2011 and 2013. Isolates were cultured using McConkey and CT-SMAC agar after enrichment, and confirmed as STEC by PCR. STEC prevalence in hides (15·4%) was higher than in faeces (10·7%) and O157:H7 was more frequent in the former (2·7%vs. 0·99%). Non-O157 HUS-related serogroups were present albeit at low frequencies. The non-O157 isolates were more heterogeneous than O157:H7 in their VG patterns, with 25/64 presenting VGs from both STEC and enterotoxigenic pathotypes (hybrid isolates). Of the STEC isolates, 62·5% were resistant at least to one antimicrobial, and no differences in AMR between O157:H7 and non-O157 were detected. All isolates had different profiles by PFGE and did not form a cluster. Overall, our results demonstrated that STEC in the cattle reservoir is still a matter of concern for human health due to the presence of HUS-related serogroups, the occurrence of certain VGs, AMR and the additional risks that hybrid isolates may pose, and thus warrants further investigation.
Cost-effectiveness of interferon-gamma release assays for tuberculosis screening in nursing homes
Authors: KOWADA A. 
Published: July 2016

SUMMARYTuberculosis (TB) in older people is a significant public health problem in low TB-incidence countries. Older persons have increased TB incidence, higher reactivation and mortality. A delay in diagnosis and initiation of TB treatment in patients with atypical clinical and radiological features is a significant factor of widespread transmission. This study aimed to evaluate the cost-effectiveness of interferon-gamma release assays [IGRAs; QuantiFERON®-TB Gold In-Tube (QFT) and T-SPOT®.TB (T-SPOT)] compared to the tuberculin skin test (TST) and chest X-ray (CXR) examination for TB screening for nursing homes. Decision trees and Markov models were constructed using a societal perspective on a lifetime horizon. Seven strategies: no screening, TST, QFT, T-SPOT, TST followed by QFT, TST followed by T-SPOT, and CXR were considered. QFT [US$ 401·9, 4·36 707 QALY (year 2014 values)] was the most cost-effective at the willingness-to-pay level of US$ 50 000/QALY gained. TST followed by QFT was the most cost-effective in residents with comorbidities. CXR was less cost-effective. Cost-effectiveness was sensitive to latent TB infection (LTBI) rate and bacillus Calmette-Guérin vaccination rate. Effective LTBI screening using IGRA is recommended to prevent TB transmission not only in nursing homes but also in local communities in low-incidence countries.
Giardia outbreak associated with a roadside spring in Rensselaer County, New York
Authors: BEDARD B. A. , ELDER R. , PHILLIPS L. , WACHUNAS M. F. 
Published: July 2016

SUMMARYIn September 2009, the Rensselaer County Department of Health investigated an increase in Giardia duodenalis cases. The epidemiological investigation identified that a source of the illness could be a roadside spring located in the eastern part of the county. Epidemiological and environmental health staff conducted a site visit to the roadside spring and found several concerns. Water samples were collected from the roadside spring and sent to the New York State Department of Health for analysis. The water sample results indicated the presence of empty Giardia cysts. Prevention methods occurred and the roadside spring was destroyed. A total of 36 laboratory-confirmed cases of Giardia were identified from this outbreak that included residents of New York State and Massachusetts.
Measuring the terminal velocity of tiny diaspores
Authors: Zotz Gerhard , Weichgrebe Tizian , Happatz Harry , Einzmann Helena J.R. 
Published: July 2016

AbstractAlthough it has long been acknowledged that seed characteristics are of major importance to the conquest of tree crowns by vascular epiphytes, there is surprisingly little quantitative evidence on the aerodynamic properties of their diaspores. We used a custom-built device to determine the terminal velocity (Vterm) of falling seeds, a parameter that has been shown to have high predictive power for the wind dispersal potential of diaspores under natural conditions. We determined Vterm of 45 species of epiphytic and terrestrial Orchidaceae, which almost doubles the currently available database for this family. Although varying by a factor of five with values of 0.09–0.4 m s−1, Vterm was invariably very slow compared to plants in general. For each species, we also took morphological data and determined seed mass. None of these parameters was linearly correlated with Vterm and neither did the average Vterm differ between species found in the two habitats, although seeds of terrestrial taxa were significantly larger and heavier. Finally, we demonstrate the potential of our device to measure Vterm of even smaller diaspores by successfully quantifying Vterm of fern spores. This tool has much potential for the quantitative study of dispersal of plants with tiny diaspores, particularly in a conservation context in fragmented landscapes.