Inverse obstacle problem for the non-stationary wave equation with an unknown background

We consider boundary measurements for the wave equation on a bounded domain $M \subset \R^2$ or on a compact Riemannian surface, and introduce a method to locate a discontinuity in the wave speed. Assuming that the wave speed consist of an inclusion in a known smooth background, the method can determine the distance from any boundary point to the inclusion. In the case of a known constant background wave speed, the method reconstructs a set contained in the convex hull of the inclusion and containing the inclusion. Even if the background wave speed is unknown, the method can reconstruct the distance from each boundary point to the inclusion assuming that the Riemannian metric tensor determined by the wave speed gives simple geometry in $M$. The method is based on reconstruction of volumes of domains of influence by solving a sequence of linear equations. For \tau \in C(\p M) the domain of influence $M(\tau)$ is the set of those points on the manifold from which the distance to some boundary point $x$ is less than $\tau(x)$.Comment: 4 figure

Actuarial neutrality across generations applied to public pensions under population ageing: effects on government finances and national saving

In welfare states, collective saving has declined to a persistently negative level, while reduced fertility and increasing longevity are leading to increasing pension liabilities. Actuarial neutrality across generations is presented as a benchmark for designing pension reforms to meet the challenges of population ageing. It is shown that this condition can be respected by a wide range of pension reforms, with very different consequences for public finance target setting. The rules for public pensions in national accounting are also discussed. Finally, the combined effects of population ageing and public pension rules on national saving are discussed.pensions, actuarial neutrality, public debt, national accounts, Oksanen

Public Pensions in the national accounts and public finance targets

Preparations are underway to revise national accounting to implement actuarial recording of pension liabilities for corporations and government as an employer. This paper extends this to unfunded public pensions with the help of ‘implicit tax' in pension contributions. The clearest advantages of the revision appear in situations where pension liabilities are shifted from the corporate sector to government, and where part of the public pension system is privatised. The proposed revision raises public debt and deficit to new orders of magnitude. The paper provides a framework for setting the debt and deficit targets under both current and proposed definitions.pensions, public debt and deficit, implicit debt, national accounts, Oksanen

Pegging the Renminbi to a Basket - Facts, Prospects and Consequences

On 19 June 2010 the Chinese authorities announced that the renminbi (RMB) was henceforth to be pegged to a currency basket. Yet, it has quite closely followed the USD, though having appreciated by 2.7 % by the time of writing. At the G20 Seoul Summit on 11-12 November 2010, China committed to further reform the RMB exchange rate regime. We discuss here what a genuine basket peg could mean for China, with the view that the weight for the EUR should obviously be significantly increased, the SDR being a strong option for practical implementation. This would also have a positive impact on the EU. China’s currency reform has possible implications for its USD-dominated assets. Their reduction could trigger a further depreciation of the USD. The potentially costly consequences call for new rules for the world financial architecture. China’s expansion will inevitably lead to a diminishing international role for the USD.China, renminbi, yuan, basket peg, foreign exchange rates

Actuarial Neutrality across Generations Applied to Public Pensions under Population Ageing: Effects on Government Finances and National Saving

In welfare states, collective saving has declined to a persistently negative level, while reduced fertility and increasing longevity are leading to increasing pension liabilities. Actuarial neutrality across generations is presented as a benchmark for designing pension reforms to meet the challenges of population ageing. It is shown that this condition can be respected by a wide range of pension reforms, with very different consequences for public finance target setting. The rules for public pensions in national accounting are also discussed. Finally, the combined effects of population ageing and public pension rules on national saving are discussed.pensions, actuarial neutrality, public debt, national accounts

A case for partial funding of pensions with an application to the EU Candidate Countries.

The paper examines the effects of ageing and makes a case for partial pre-funding of pensions. The argument is based on inter-generational fairness in a situation where pension expenditure as compared to wages increases due to low fertility and increasing longevity. We illustrate the approach by using data representing a typical EU Candidate Country of Central and Eastern Europe with a relatively high pension replacement rate. Pre-funding can take place within the public sector or in a privatised second pillar. We emphasise the need for a consistent framework to cover the many different institutional options available for pension financing.pension systems, demographics, reform

Population ageing and public finance targets

The paper incorporates intergenerational fairness into a framework to analyse long-term sustainability of public finances under population ageing. It establishes a link between ageing-related public expenditure projections and public finance targets, thereby clarifying the connection between pension reforms and general government budget balance and debt targets.population ageing, public finances, sustainability of public finances, budget balance targets, pension reforms, pensions, Oksanen

Public Pensions in the National Accounts and Public Finance Targets

Preparations are underway to revise national accounting to implement actuarial recording of pension liabilities for corporations and government as an employer. This paper extends this to unfunded public pensions with the help of ‘implicit tax’ in pension contributions. The clearest advantages of the revision appear in situations where pension liabilities are shifted from the corporate sector to government, and where part of the public pension system is privatised. The proposed revision raises public debt and deficit to new orders of magnitude. The paper provides a framework for setting the debt and deficit targets under both current and proposed definitions.pensions, public debt and deficit, implicit debt, national accounts

A Case for Partial Funding of Pensions with an Application to the EU Candidate Countries

The paper examines the effects of ageing and makes a case for partial pre-funding of pensions. The argument is based on inter-generational fairness in a situation where pension expenditure as compared to wages increases due to low fertility and increasing longevity. We illustrate the approach by using data representing a typical EU Candidate Country of Central and Eastern Europe with a relatively high pension replacement rate. Pre-funding can take place within the public sector or in a privatised second pillar. We emphasise the need for a consistent framework to cover the many different institutional options available for pension financing.Pension system reform, partial pre-funding, ageing