Delta-shocks and vacuums in zero-pressure gas dynamics by the flux approximation

In this paper, firstly, by solving the Riemann problem of the zero-pressure flow in gas dynamics with a flux approximation, we construct parameterized delta-shock and constant density solutions, then we show that, as the flux perturbation vanishes, they converge to the delta-shock and vacuum state solutions of the zero-pressure flow, respectively. Secondly, we solve the Riemann problem of the Euler equations of isentropic gas dynamics with a double parameter flux approximation including pressure. Further we rigorously prove that, as the two-parameter flux perturbation vanishes, any Riemann solution containing two shock waves tends to a delta shock solution to the zero-pressure flow; any Riemann solution containing two rarefaction waves tends to a two-contact-discontinuity solution to the zero-pressure flow and the nonvacuum intermediate state in between tends to a vacuum state.Comment: 17 pages, 4 figures, accepted for publication in SCIENCE CHINA Mathematic

Retirement Choice Simulation in Household Settings with Heterogeneous Pension Plans

This paper estimates a structured life cycle model of family retirement decision using a unique historical dataset back simulated from Living in Ireland survey. Our model takes the advantages of the dataset and models retirement decisions in terms of monetary and leisure incentives, which reflect the complex welfare system in Ireland. The household extension version of the model adapts a collective modelling approach, where the intra-household bargaining is considered. We further incorporate complimentary leisure, which allows us to analyse the interactions of spouses' retirement timing. This methodology enables us to capture the dynamics of retirement and tax-benefit policies and can be used to simulate the effect of policy reform on household retirement behaviours. The paper, in addition, applies the model to assess individual budgetary implications and the labour market impact of rising the minimum retirement age. Our simulation shows that increasing the minimum age for state pension entitlement to 70 would only delay the retirement by less than 2 years according to the individual based model. When we consider the intra-household bargaining and the higher preference of leisure found in the dual career households, the effect of postponing retirement further declines. The result suggests barely postponing the minimum retirement age for state pension without redefining the occupation and private pension rules will only have limited impact for household retirement behaviour in Ireland.retirement, choice modelling, microsimulation

A Continuous Labour Supply Model in Microsimulation: A Life-Cycle Modelling Approach with Heterogeneity and Uncertainty Extension

This paper advances a structural inter-temporal model of labour supply that is able to simulate the dynamics of labour supply in a continuous setting and to circumvent two main drawbacks of most of the existing models. The first limitation is the inability to incorporate individual heterogeneity as every agent is sharing the same parameters of the utility function. The second one is the strong assumption that individuals make decisions in a world of perfect certainty. Essentially, this paper offers an extension of marginal-utility-of-wealth-constant labour supply functions known as "Frisch functions" under certainty and uncertainty with homogenous and heterogeneous preferences. Two alternative models are proposed for capturing individual heterogeneity. First, a "fixed effect vector decomposition" model, which allows the individual specific effects to be correlated with the explanatory variables included in the labour supply model, and second, a mixed fixed and random coefficient model, which incorporates a higher degree of individual heterogeneity by specifying individual coefficients. Uncertainty is controlled for by introducing an expectation correction into the model. The validation of each simulation model is realized in comparison with the standard Heckman model. The lifetime models based on the fixed effect vector decomposition yield the most stable and unbiased simulation results, both under certainty and uncertainty. Due to its improved accuracy and stability, this lifetime labour supply model is particularly suitable for enhancing the performance of the pension models, thus providing a better reference for policymaking.dynamic microsimulation, lifetime labour supply

セカイ ブンガク ノ ナカ ノ イタロ ･ カルヴィーノ : チュウゴク､ ニホン ニオケル ジュヨウ カラ

PDF/A formatsAccess: via World Wide Web"Università degli Studi di Treno in cotutela con Tokyo University of Foreign Studies, dottorato di ricerca in studi umanistici"東京外国語大学大学院総合国際学研究科博士 (学術) 論文 (2017年9月)Author's thesis (Ph.D)--Tokyo University of Foreign Studies, 2017博甲第235号Other title from Japanese summaryBibliography: p. 195-212Summary in English and Japanese東京外国語大学 (Tokyo University of Foreign Studies)博士 (学術

Supramolecular modification of selected antitubercular drugs

Includes abstract.Includes bibliographical references.The author's objective was to prepare new solid phases of the antitubercular drug isoxyl [specifically polymorphs, solvates, cyclodextrin (CD) inclusion complexes and cocrystals] and to isolate and characterise a range of solvated forms of the rifamycin antibioticsrifampicin and rifaximin

Quality Risk Research in the Supply Chain Environment

Quality issue on supply chain is essential. It affects not only the cost of quality, but also customer’s satisfaction. Supply chain’s upstream should be good quality, the level of quality risk management can be introduced, and it can consider the current cost of quality, combine with supply chain risk transfer and improve overall efficiency. The paper will quantify the quality of risk, and use mathematical models to simulate risk transfer to help suppliers to determine the best lever of quality risk management