One of the classical problems in finance is that of an economic unit who aims at maximizing his expected life-time utility from consumption and/or terminal wealth by an effective asset-liability management. The purpose of this thesis is to determine the optimal investment strategies , from the point of view of their economic utility, for individual and institutional investors such pension funds.

This thesis in economics includes three self-contained papers united by a common theme: the importance of economic fluctuations within and between countries for capital flows and risk sharing inside and across national borders. The first two papers study the determinants of workers’ remittances, as well as the consequences for macroeconomic volatility for the countries that receive them, using econometric methods and a general equilibrium model. The third paper studies whether two challenges to international real business cycle models, the so called ”Quantity Puzzle” and the positive relationship between financial integration and output correlations, obtain for European countries and regions. As a second step, it also investigates multilateral channels for risk sharing. / Diss. Stockholm : Handelshögskolan, 2010. Sammanfattning jämte 3 uppsatser.

This article investigates the impacts of asymmetric information within a Lucas (1978) asset pricing economy. Asymmetry enters via the assumption that one group of agents is equipped with superior information about the dividend process. The agents maximize their lifetime utility of the underlying consumption process obtained from the agents' budget constraints, where the agents have the opportunity to invest in a risk asset to transfer income from the current to future periods. Since a closed form solution for the market price cannot be derived analytically, projection methods are applied, as described in Judd (1998), to approximate the expectation integrals in the agents' Euler equation. We derive the result that the informed trader only clearly improves his situation as compared to the non-trade situation if the uninformed trader only observes his own endowment but not the endowment of the informed trader. In the case where agents observe each others' endowment trade never results in a Pareto improvement. (auhtor's abstract) / Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

The 7σ discrepancy between the charge radius of the proton as extracted from electronic hydrogen to the determination from muonic hydrogen, coined the proton ``radius puzzle", challenges our understanding of physics based on the standard model. High-precision measurements have been conducted on muonic deuterium to study whether the discrepancy with ordinary atoms persists or varies with mass number. For the success of this experimental campaign accurate theoretical calculations of the nuclear structure corrections in muonic deuterium (μD) are required. In this work we contributed by accurately and precisely calculating them using state-of-the-art nuclear potentials derived from chiral effective field theory. We performed a multipole expansion of the electromagnetic operator and accounted for Coulomb, relativistic and finite-nucleon-size corrections. Our determinations will impact the accuracy of the experimental program. / October 2015

After a brief overview of the standard attempts to give the persistence conditions of artifacts through time and material changes, I develop and present an account which capitalizes on Koons’s theory that artifacts are in some robust and important way social practices in order to explain their persistence through time. After one unsuccessful attempt to formulate a view that is not susceptible to Ship of Theseus like problems concerning the persistence conditions of artifacts, I present the full view: artifacts become artifacts when they are arranged in a particular formal manner by someone who is engaging in a creative social practice. The artifact then remains the same artifact so long as its form is sufficiently preserved and maintained according to maintaining social practices. In this way, the social practice that unifies the artifact is like the life that unifies an organism—so long as the social practice and the form persist, the artifact is the same artifact. To conclude, I look at several problems my view cannot yet account for, such as the persistence conditions of objects that are not manmade artifacts, and the commitment to ontic vagueness that my view seems to entail. / text

What meaning does a name have in a sentence? How do we escape the inevitable difficulties that arise in delineating an individual's meaning through one's speech? The need arises for a distinction between proper names on the basis of the kinds of objects to which they refer. This distinction can provide the theoretical tools needed to solve the problems of empty names, negative existential statements, cognitive significance and substitution failure. Through a study of these issues, the fallacies inherent in current theories of meaning for proper names becomes apparent, as they fail to provide adequate or complete solutions. By elucidating a distinction between two kinds of proper names, labels and tags, we are able to provide solutions to the problems of naming where other theories fail.

With the advance of wireless access technologies, the IEEE 802.11 wireless local area network (WLAN) has gained significant increase in popularity and deployment due to the substantially improved transmission rate and decreased deployment costs. However, this same widespread deployment makes WLANs an attractive target for network attacks. Several vulnerabilities have been identified and reported regarding the security of the current 802.11 standards. To address those security weaknesses, IEEE standard committees proposed the 802.11i amendment to enhance WLAN security. The 802.11i standard has demonstrated the capability of providing satisfactory mutual authentication, better data confidentiality, and key management support, however, the design of 802.11i does not consider network availability. Therefore, it has been suggested that 802.11i is highly susceptible to malicious denial-of-service (DoS) attacks, which exploit the vulnerability of unprotected management frames. This research first investigates common DoS vulnerabilities in a Robust Security Network (RSN), which is defined in the 802.11i standard, and presents an empirical analysis of such attacks – in particular, flooding-based DoS attacks. To address those DoS issues, this thesis proposes a novel design and implementation of a lightweight stateless authentication scheme that enables wireless access points (APs) to establish a trust relationship with an associating client and derive validating keys that can be used to mutually authenticate subsequent layer-2 (link layer) management frames. The quality of service provisioning for real-time services over a WLAN requires the total latency of handoff between APs to be small in order to achieve seamless roaming. Thus, this thesis further extends the proposed link-layer authentication into a secure fast handoff solution that addresses DoS vulnerabilities as well as improving the existing 802.11i handoff performance. A location management scheme is also proposed to minimise the number of channels required to scan by the roaming client in order to reduce the scanning delay, which could normally take up 90% of the total handoff latency. In order to acquire practical data to evaluate the proposed schemes, a prototype network has been implemented as an experimental testbed using open source tools and drivers. This testbed allows practical data to be collected and analysed. The result successfully demonstrated that not only the proposed authentication scheme eradicates most of the DoS vulnerabilities, but also substantially improved the handoff performance to a level suitable for supporting real-time services.

The starting point of this PhD dissertation is related to the Shimer puzzle, i.e. the unability of the search and matching model to reproduce the high volatility of the unemployment rate. Real wage rigidities were considered as the main solution to this puzzle. Nevertheless, Sveen and Weinke (2008) argue that those rigidities would not have any impact on the unemployment volatility when hours per worker are determined by the firms. In the first chapter, we argue that the capacity of real wage rigidities to solve the puzzle critically depends on the way that rigidities are introduced. When real wage stickiness results from the "credible bargaining" (Hall and Milgrom ,2008), we show that the unemployment volatility is magnified, even for hours being firms' decisions. A significant stabilization trade-off between inflation and unemployment is moreover restituted. However, we stress in the second chapter that the credible bargaining delivers a moderate degree of wage rigidity and then requires unrealistic values for some parameters to completely replicate the unemployment volatility. We integrate asymmetric information into this framework and show that the resulting higher wage stickiness fully reproduces the volatility for a plausible calibration. ln the last chapter, we emphasize that it is possible to solve the puzzle without resting on real wage stickiness, by considering a particular calibration of the model with endogenous separations. We also highlight a central mechanism of this framework, for which the volatility of the separation rate amplifies that of the job finding rate.

This dissertation collects five independent essays. The first essay is An Alternative Explanation of the Price Puzzle. The most widely accepted explanation of the price puzzle points to an inadequate performance of the VAR in forecasting inflation. This essay suggests that the finding of a price puzzle is due to a seemingly innocent misspecification in taking the theoretical model to the data: a measure of output gap is not included in the VAR (output alone being used instead), while this variable is a crucial element in every equation of the theoretical models. When the VAR is correctly specified, the price puzzle disappears. Building on results contained in the first paper, the second-- Stronger Evidence of Long-Run Neutrality: A comment on Bernanke and Mihov---improves the empirical performance of standard models on the prediction that a monetary policy shock should have temporary effects on output. It turns out that the same misspecification causing the price puzzle is also responsible for overestimation of the time needed for the effects on output of a monetary policy shock to die out. The point can be proven in a theoretical economy, and is confirmed on US data. Monetary Policy Without Monetary Aggregates: Some (Surprising) Evidence , joint with Giovanni Favara) is the third essay. It points to what seems to be a falsified prediction of models in the New-Keynesian framework. In this framework monetary aggregates are reserved a pretty boring role, so boring that they can be safely excluded from the final lay out of the model. These models predict that a money demand shock should have no effect on output, inflation and interest rate. However, the prediction seems to be quite wrong Inflation Forecast Targeting, joint with Paul Söderlind, takes a step outside the representative-agent framework. In RE models, all agents typically have the same information set, and therefore make the same predictions. However, in the real even professional forecasters show substantial disagreement. This disagreement can have an impact on asset prices and transaction volumes, among other things. However, there is no unique way of aggregating forecasts (or forecast probability density functions) into a measure of disagreement. The paper deals with this problem, surveying some proposed methods. The most appropriate measure of disagreement turns out to depend on the intended use, that is, on the model. Moreover, forecasters underestimate uncertainty. Constitutions and Central-Bank Independence: An Objection to McCallum's Second Fallacy, joint with Giancarlo Spagnolo , is an excursion into the field of Political Economy. The essay provides some foundations for the assumption that renegotiating a delegation contract can be costly by illustrating how political institutions can generate inertia in re-contracting, reduce the gains from it or prevent it altogether. Once the nature of renegotiation costs has been clarified, it is easier to see why certain institutions can mitigate or solve dynamic inconsistencies better than others. / Diss. Stockholm : Handelshögsk., 2001

Zugl.: Oestrich-Winkel, Europ. Business School, Diss., 2008. / Hergestellt on demand.