A discrepancy bound for deterministic acceptance-rejection samplers beyond $$N^{-1/2}$$ in dimension 1

In this paper we consider an acceptance-rejection (AR) sampler based on deterministic driver sequences. We prove that the discrepancy of an N element sample set generated in this way is bounded by \(\mathcal {O} (N^{-2/3}\log N)\), provided that the target density is twice continuously differentiable with non-vanishing curvature and the AR sampler uses the driver sequence \(\mathcal {K}_M= \{( j \alpha , j \beta ) ~~ mod~~1 \mid j = 1,\ldots ,M\},\) where \(\alpha ,\beta \) are real algebraic numbers such that \(1,\alpha ,\beta \) is a basis of a number field over \(\mathbb {Q}\) of degree 3. For the driver sequence \(\mathcal {F}_k= \{ ({j}/{F_k}, \{{jF_{k-1}}/{F_k}\} ) \mid j=1,\ldots , F_k\},\) where \(F_k\) is the k-th Fibonacci number and \(\{x\}=x-\lfloor x \rfloor \) is the fractional part of a non-negative real number x, we can remove the \(\log \) factor to improve the convergence rate to \(\mathcal {O}(N^{-2/3})\), where again N is the number of samples we accepted. We also introduce a criterion for measuring the goodness of driver sequences. The proposed approach is numerically tested by calculating the star-discrepancy of samples generated for some target densities using \(\mathcal {K}_M\) and \(\mathcal {F}_k\) as driver sequences. These results confirm that achieving a convergence rate beyond \(N^{-1/2}\) is possible in practice using \(\mathcal {K}_M\) and \(\mathcal {F}_k\) as driver sequences in the acceptance-rejection sampler.     

Sequential testing of gradual changes in the drift of a stochastic process

In this paper, some sequential monitoring procedures are constructed and analyzed for detecting a “gradual” change in the drift parameter of a general stochastic process satisfying a certain (weak) invariance principle. It is shown that the tests can be constructed such that the “false alarm rate” attains a prescribed level (say) α and that the tests have “asymptotic power 1”. A more precise analysis of the procedures under the alternative proves that the stopping times, suitably normalized, have a standard normal limiting distribution. A few results from a small simulation study are also presented in order to give an idea of the finite sample behaviour of the suggested procedures.     

Extending Little’s Law to single order throughput times

It has long been established that the mean throughput time is a result from the relationship between the work in process (WIP) and output rate. In reality, however, throughput times are frequently dispersed broadly around this mean. With the aid of a model originally developed for lateness, it is now possible to describe the throughput times of individual orders. Accordingly, the throughput time can be divided into two components: WIP-dependent throughput time and sequence-dependent throughput time.     

The Effect of Remittances on Economic Growth in Kyrgyzstan and Macedonia: Accounting for Financial Development

Kyrgyzstan and Macedonia have experienced a reasonable increase in remittances over the last twenty‐five years. Subsequently, the extent to which remittances can be instrumental for economic development of the two countries has gained serious attention in recent development dialogues. The aim of this study is to examine the impact of remittances versus financial development on the economic growth of the two counties, complementing the burgeoning interest and focus on remittances for policy. The short‐run and the long‐run effects and the causality dynamics of remittances and financial development, are explored. The results show a long‐run positive impact of remittances on the economic growth of these countries. The impact of financial development is negative, significant only for Kyrgyzstan and not statistically significant for Macedonia. The causality results show that remittances support economic growth for Kyrgyzstan, whereas economic growth appears to propel remittances for Macedonia.     

THE EFFECT OF BENEFIT SANCTIONS ON THE DURATION OF UNEMPLOYMENT

This paper investigates the effectiveness of unemployment benefit sanctions in reducing unemployment duration. Swiss data on benefit sanctions allow us to separate the effect of a warning that a person is not complying with eligibility requirements from the effect of the actual enforcement of a benefit sanction. Moreover, public employment services are given substantial leeway in setting the monitoring intensity. Results indicate that both warning and enforcement have a positive effect on the exit rate out of unemployment, and that increasing the monitoring intensity reduces the duration of unemployment of the nonsanctioned. (JEL: J64, J65, J68)     

Signaling the Strategic Value of Knowledge

Firms competing primarily on knowledge resources face problems in informing relevant external stakeholders about the value of that knowledge without losing its value. This knowledge may be transferred to stakeholders only at great expense, or that transfer of knowledge to stakeholders may simultaneously promote its transfer to competitors. By conceptualizing firms and the environments within which they compete to differ in levels of uncertainty, this paper develops a framework to examine signaling mechanisms firms can use to effectively signal the value of their knowledge to two key stakeholder groups, the capital and labor markets, while avoiding associated transfer problems.     

Geostatistical analysis of hydraulic conductivity related data based on core samples from a heterogeneous fluvial aquifer

Summary This paper presents a case study for the geostatistical characterization of the hydraulic conductivity field of a fluvial aquifer. An experimental distribution of hydraulic conductivity values was obtained from core samples, which were analysed in the laboratory with regard to their grain size distribution. The geostatistical analysis was performed on (i) hydraulic conductivity data derived from the grain size distributions applying an empirical relationship, (ii) binary transforms of the hydraulic conductivity data using thresholds, and (iii) categorical variables obtained by a K-means clustering of the grain size distributions. Although the available data base is rather small, the results show that the investigated aquifer is distinctly heterogeneous and anisotropic with respect to hydraulic conductivity and soil texture.