Optimal Insurance Contracts without the Non-Negativity Constraint on Indemnities Revisited

In the literature on optimal indemnity schedules, indemnities are usually restricted to be non-negative. Gollier (1987) shows that this constraint might well bind: insured could get higher expected utility if insurance contracts would allow payments from the insured to the insurer at some losses. However, due to the insurers’ cost function Gollier supposes, the optimal insurance contract he derives underestimates the relevance of the non-negativity constraint on indemnities. This paper extends Gollier’s findings by allowing for negative indemnity payments for a broader class of insurers’ cost functions.Insurance, Indemnity, Deductible, Co-Insurance

Multiple Losses, Ex-Ante Moral Hazard, and the Non-Optimality of the Standard Insurance Contract

Under certain conditions the optimal insurance policy will offer full coverage above a deductible, as Arrow and others have shown long time ago. Interestingly, the same design of insurance policies applies in case of a single loss and ex-ante moral hazard. However, many insurance policies provide coverage against a variety of losses and the possibilities for the insured to affect the probabilities of each possible loss might be substantially different. The optimal design of a insurance contract providing coverage against different losses therefore should generally differ from the standard form under moral hazard. The paper concentrates on the conditions under which the standard insurance contract holds under moral hazard and more than one loss. It gives some evidence that many insurance contracts should be split up. The main result is, that the relative changes of probabilities due to precautious activities are decisive. On the other hand, under moral hazard it is rarely ever optimal to combine two losses in one insurance contract prescribing only a single deductible for both losses if both losses can occur simultaneously.insurance, multiple losses,moral hazard

Deductible or Co-Insurance: Which is the Better Insurance Contract under Adverse Selection?

The standard solution to adverse selection is the separating equilibrium introduced by Rothschild and Stiglitz. Usually, the Rothschild-Stiglitz argument is developed in a model that allows for two states of the world only. In this paper adverse selection is dis-cussed for continuous loss distributions. This gives rise to the new problem of finding the proper form of an insurance contract to impose partial insurance of the low risks. This paper contributes to the discussion on optimal insurance. It analyzes two basic forms of insurance contracts: A contract with a deductible and a contract imposing a positive co-insurance rate. Since high risks can always self-reveal themselves as high risks and buy the optimal insurance contract at high risks’ premiums the Pareto-superior insurance contract is the one that leaves the low risks with higher expected utility while deterring high risks from joining the contract that is designed for low risks. The deductible contract turns out to be superior if premiums contain a sufficiently high loading.Insurance, Adverse Selection, Deductible, Co-Insurance

Optimal Insurance Contracts without the Non-Negativity Constraint on Indemnities Revisited

In the literature on optimal indemnity schedules, indemnities are usually restricted to be non-negative. Gollier (1987) shows that this constraint might well bind: insured could get higher expected utility if insurance contracts would allow payments from the insured to the insurer at some losses. However, due to the insurers’ cost function Gollier supposes, the optimal insurance contract he derives underestimates the relevance of the non-negativity constraint on indemnities. This paper extends Gollier’s findings by allowing for negative indemnity payments for a broader class of insurers’ cost functions

High-level programming of stencil computations on multi-GPU systems using the SkelCL library

The implementation of stencil computations on modern, massively parallel systems with GPUs and other accelerators currently relies on manually-tuned coding using low-level approaches like OpenCL and CUDA. This makes development of stencil applications a complex, time-consuming, and error-prone task. We describe how stencil computations can be programmed in our SkelCL approach that combines high-level programming abstractions with competitive performance on multi-GPU systems. SkelCL extends the OpenCL standard by three high-level features: 1) pre-implemented parallel patterns (a.k.a. skeletons); 2) container data types for vectors and matrices; 3) automatic data (re)distribution mechanism. We introduce two new SkelCL skeletons which specifically target stencil computations – MapOverlap and Stencil – and we describe their use for particular application examples, discuss their efficient parallel implementation, and report experimental results on systems with multiple GPUs. Our evaluation of three real-world applications shows that stencil code written with SkelCL is considerably shorter and offers competitive performance to hand-tuned OpenCL code

Pareto-Verbesserungen in der Sozialversicherung durch Selbstselektion ihrer Mitglieder

In der Sozialversicherung gelten Risikoselektionen als unerwuenscht, weil sie die Gefahr mit sich bringen, dass der einheitliche Risikopool in der Sozialversicherung aufgespalten und die sozialpolitisch gewuenschten Umverteilungsstroeme zwischen den Versicherten reduziert werden. Der Beitrag zeigt am Beispiel der sozialen Krankenversicherung in der Schweiz und der Bundesrepublik Deutschland auf, dass die Selbstselektion von Versicherten in der Sozialversicherung produktiv, das heisst wohlfahrtssteigernd eingesetzt werden kann, ohne den ‚solidarischen‘ Charakter der Sozialversicherung in Frage zu stellen. Konkret wird vorgeschlagen, den Versicherten innerhalb eines durch einen Risikoausgleich gestuetzten Wettbewerbs zwischen den Krankenkassen eine groessere Wahlfreiheit ueber die Hoehe des Versicherungsschutzes einzuraeumen. Fuer Versicherte mit niedrigem Risiko oder hohem Einkommen kann es sinnvoll sein, ihren Versicherungsschutz innerhalb der Sozialversicherung zu reduzieren, obwohl sie dann aufgrund des konstanten Transfers an andere Versicherte der sozialen Krankenversicherung einen hoeheren Preis pro Einheit Sozialversicherungsschutz zu zahlen haben.self selection, social insurance, Germany

Finanzintermediaere - Groessennachteile und Spezialisierungsvorteile

Fuer das Entstehen von Finanzintermediaeren existieren in der theoretischen Literatur zahlreiche ueberzeugende Begruendungen, die konsequent zu Ende gedacht allerdings auf einen Finanzintermediaer als natuerliches Monopol hinauslaufen. Beitraege, die Grenzen fuer das Wachstum von Finanzintermediaeren aufzeigen, sind indessen selten. Das vorliegende Papier baut auf einem Modell von Millon und Thakor auf. Die betrachteten Akteure sind die einzelnen Informationsagenten (z.B. Sachbearbeiter) des Finanzintermediaers, die einen gewissen Aufwand fuer das Sammeln von Informationen ueber ihre Kunden betreiben muessen. Zu einer freiwilligen und oekonomisch sinnvollen Zusammenarbeit zwischen ihnen kommt es nur dann, wenn sie im Rahmen ihrer Zusammenarbeit Informationsteilung betreiben koennen. Die wesentlichen neuen Ergebnisse des vorliegenden Beitrags sind, dass es unter heterogenen Informationsagenten nur zu Gruppenbildungen von recht homogenen (spezialisierten) Agenten kommen wird. Zugleich bestehen aber dynamische Anreizwirkungen, durch welche eben diese Homogenitaet innerhalb eines Finanzintermediaers bedroht wird. Die dynamischen Anreizwirkungen innerhalb eines Finanzintermediaers sind nicht nur fuer die begrenzte Groesse von Finanzintermediaeren verantwortlich, sondern koennen sogar den Keim fuer eine spaetere Aufspaltung oder Aufloesung von Finanzintermediaeren bilden.financial intermediaries, economies of scale

Observing a Quantum Phase Transition by Measuring a Single Spin

We show that the ground-state quantum correlations of an Ising model can be detected by monitoring the time evolution of a single spin alone, and that the critical point of a quantum phase transition is detected through a maximum of a suitably defined observable. A proposed implementation with trapped ions realizes an experimental probe of quantum phase transitions which is based on quantum correlations and scalable for large system sizes.Comment: 5 pages, 2 figure

Artificial infestation of grape berry and grape vine moth : a new method to assay the efficacy of insecticides in grape vines

Bei der Prüfung von Insektiziden gegen die Traubenwickler Lobesia botrana DEN. & SCHIFF. und Eupoecilia ambiguella HBN. (Lepidoptera: Tortricidae) im Freiland ist ein ausreichender Befall mit den Schadinsekten notwendig, um statistisch auswertbare Ergebnisse zu erzielen. Dem steht jedoch ein jährlich stark wechselnder Befallsdruck und ein oft stark geklusterter Befall, selbst innerhalb einer eng umgrenzten Rebanlage, entgegen. Hinzu kommen erhebliche Probleme mit dem richtigen Timing der Behandlung, bedingt durch eine sehr lange Flugzeit der Traubenwicklerarten, was häufig zu einer geringen Effizienz und schlechten Vergleichbarkeit der Mittel führt. Für die Entwicklung von Insektiziden bedingen diese Voraussetzungen eine große Anzahl von Versuchen, die mit hohen Kosten verbunden sind Abhilfe kann für viele Fragestellungen ein künstlich erzeugter Befall geben. Die Methode soll hier kurz vorgestellt und die Anwendung exemplarisch an Versuchen mit beiden Traubenwicklerarten dargestellt werden.For a proper evaluation of insecticides against Lobesia botrana DEN. & SCHIFF. and Eupoecilia ambiguella HBN. (Lepidoptera: Tortricidae) in the field, a sufficient infestation is necessary. Unfortunately, the degree of infestation varies from year to year and is not even uniform in one vineyard. Furthermore, the timing of the application is quite difficult, because of the long flight period of these species. This often results in a poor efficacy and comparability of the products tested. We therefore developed a method to artificially infest flower or fruit clusters. Pieces of wire covered with green plastic were placed in cages with adult moths. This material was found to be an excellent substrate for egg laying in both species. These sticks, covered with eggs, were transferred to the study areas and carefully mounted individually at grape bunches. This method caused a quite uniform infestation within the whole experimental blocks and allowed a proper determination of the optimal time of application. Yet another advantage is that experiments can be done independently from the natural infestation and flight period. It is possible to vary the time of the exposition of the “egg stick” in the field, the hatch of the larvae and the application itself. This allows to study a variety of problems, such as the optimisation of the time of application and the estimation of the residual activity (persistency) of products