A Novel Hybrid Quicksort Algorithm Vectorized using AVX-512 on Intel Skylake

The modern CPU's design, which is composed of hierarchical memory and SIMD/vectorization capability, governs the potential for algorithms to be transformed into efficient implementations. The release of the AVX-512 changed things radically, and motivated us to search for an efficient sorting algorithm that can take advantage of it. In this paper, we describe the best strategy we have found, which is a novel two parts hybrid sort, based on the well-known Quicksort algorithm. The central partitioning operation is performed by a new algorithm, and small partitions/arrays are sorted using a branch-free Bitonic-based sort. This study is also an illustration of how classical algorithms can be adapted and enhanced by the AVX-512 extension. We evaluate the performance of our approach on a modern Intel Xeon Skylake and assess the different layers of our implementation by sorting/partitioning integers, double floating-point numbers, and key/value pairs of integers. Our results demonstrate that our approach is faster than two libraries of reference: the GNU \emph{C++} sort algorithm by a speedup factor of 4, and the Intel IPP library by a speedup factor of 1.4.Comment: 8 pages, research pape

Social Protection Convergence in the European Union: Impact of Maastricht Treaty

The main goal of this paper is to test the convergence of social protection expenditures and, more specifically, to examine the incidence of the Maastricht Treaty on this process. We tested several hypotheses of convergence on 12 EU Member States between 1980 and 2000, by considering two indicators: social protection expenditure as percentage of GDP and social protection expenditure per capita. The cross sectional tests of ? and ??convergence show that, for the two indicators, these two assumptions are checked for the whole of the period. On the other hand, the period division in two subperiods intended to locate the Maastricht effect indicates a rupture since 1993. Then, panel data estimations of conditional ?-convergence confirm the existence of a process of conditional convergence and reveal the significant role of the debt criterion of Maastricht. The coexistence of absolute and conditional ?-convergence is not incompatible. It evokes the possible idea of a European Social Snake rather than of a single Social Model.Welfare-state, Social protection, Convergence, European Union, Panel data estimation

Underlying structures of risk response measures among small and medium contractors in South Africa

Although attention has been given to the measures used to respond to risk in the construction industry (CI), there is limited literature that scrutinizes underlying structures of risk response measures (RRMs) especially among small and medium enterprises (SMEs). This study, therefore, presents findings from an exploratory factor analysis (EFA) of RRMs. A positivist paradigm was adopted to collect empirical raw data from 181 conveniently sampled respondents in Gauteng, South Africa (SA), using a structured questionnaire. The results support the extant literature and empirically established the structural composition of risk response by two constructs. The construct with emerged measures was termed trailing measures while the one with popular measures was termed leading measures of risk response. However, the study yielded a two-factor model with all the six items supposed to measure risk response. Based on the results obtained, it seems that risk avoidance and risk mitigation are reliable measures for measuring risk response. This study could thus serve as a reference for the accurate measurement of risk response and for the development of agreed responses for each risk, including an appropriate strategy and specific responses to implement the chosen strategy. The study was limited to the CI and to a lesser extent, construction SMEs in Gauteng; hence the findings cannot be generalized to all SMEs in SA

Panowanie Habsburgów w Europie

Niniejszy tekst jest wykładem profesora J. Berengera wygłoszonym w dniu 20 października 1994 podczas Jego wizyty naukowej w lnstytucie Historii Filii Uniwersytetu Warszawskiego w Białymstoku.Jean Berenger jest obecnie profesorem historii nowożytnej na Uniwersytecie Paris-Sorbonne. Od ponad trzydziestu lat zajmuje się problematyką Europy Środkowej. Oprócz prac doktorskich poświęconych Austrii (Finances at absolutisme autrichien dans la seconds moitié du XVII ème siécle, Paris 1975) i Węgrom (Les Gravamina, Remontrances des Diètes de Hongris de 1655 à 1681, Paris 1973) jest autorem wielu książek i publikacji, z których najważniejsze to: Historie de l'Empire des Habsbourg de 1279 à 1918, Paris 1990), l'Autriche-Hongria (1815-1918), Paris 1994, La Tchécoslovaquie, Paris 1978 oraz Histoire de l'Autriche, Paris 1994.5-1

Agricultural Technology Adoption and Adaptation under Climate Change: Microevidence from Niger

Many regions of Sub-Saharan Africa (SSA) are experiencing fast increases in human population pressure and urbanization. By 2050, feeding a planet of 9 billion people will require an estimated 50 percent increase in agricultural production. Farmers in in the Sahel are exposed to a highly variable weather over time, and to their limited adaptive capacity, therefore often use livestock as income generator, export earnings, and as insurance against weather risk. There is an increasing demand for livestock products, which increase pressure on crop residues use on the land. In this study, I use panel socio-economic data combined with village rainfall level from Niger to investigate how different types of weather shocks including drought and wet conditions influence farmer’s inputs adaption. Using cluster and year fixed effects estimations, I find that exposure to drought results in a strong and deep decrease in use of crop residues on the soil, which is particularly concerning because crop residue is crucial for soil protection, and fertility. I also find that one of the reasons poor Nigerien farmers remove crop residues on their land, is for livestock feeding purposes. This results in a bad synergy because removing crop residues could decrease long-term food production, and might keep households in poverty trap. Other determinants affecting inputs adoption on the land including temperature increase, income, farm size, and rainfall level of the previous year. I discuss policy recommendations

Social protection convergence in the European Union: Impact of Maastricht treaty

The main goal of this paper is to test the convergence of social protection expenditures and, more specifically, to examine the incidence of the Maastricht Treaty on this process. We tested several hypotheses of convergence on 12 EU Member States between 1980 and 2000, by considering two indicators: social protection expenditure as percentage of GDP and social protection expenditure per capita. The cross sectional tests of a and ß-convergence show that, for the two indicators, these two assumptions are checked for the whole of the period. On the other hand, the period division in two sub-periods intended to locate the Maastricht effect indicates a rupture since 1993. Then, panel data estimations of conditional ß-convergence confirm the existence of a process of conditional convergence and reveal the significant role of the debt criterion of Maastricht. The coexistence of absolute and conditional ß-convergence is not incompatible. It evokes the possible idea of a European "Social Snake" rather than of a single Social Model

Computing the sparse matrix vector product using block-based kernels without zero padding on processors with AVX-512 instructions

The sparse matrix-vector product (SpMV) is a fundamental operation in many scientific applications from various fields. The High Performance Computing (HPC) community has therefore continuously invested a lot of effort to provide an efficient SpMV kernel on modern CPU architectures. Although it has been shown that block-based kernels help to achieve high performance, they are difficult to use in practice because of the zero padding they require. In the current paper, we propose new kernels using the AVX-512 instruction set, which makes it possible to use a blocking scheme without any zero padding in the matrix memory storage. We describe mask-based sparse matrix formats and their corresponding SpMV kernels highly optimized in assembly language. Considering that the optimal blocking size depends on the matrix, we also provide a method to predict the best kernel to be used utilizing a simple interpolation of results from previous executions. We compare the performance of our approach to that of the Intel MKL CSR kernel and the CSR5 open-source package on a set of standard benchmark matrices. We show that we can achieve significant improvements in many cases, both for sequential and for parallel executions. Finally, we provide the corresponding code in an open source library, called SPC5.Comment: Published in Peer J C

Perfectly Matched Layers in a Divergence Preserving ADI Scheme for Electromagnetics

For numerical simulations of highly relativistic and transversely accelerated charged particles including radiation fast algorithms are needed. While the radiation in particle accelerators has wavelengths in the order of 100 um the computational domain has dimensions roughly 5 orders of magnitude larger resulting in very large mesh sizes. The particles are confined to a small area of this domain only. To resolve the smallest scales close to the particles subgrids are envisioned. For reasons of stability the alternating direction implicit (ADI) scheme by D. N. Smithe et al. (J. Comput. Phys. 228 (2009) pp.7289-7299) for Maxwell equations has been adopted. At the boundary of the domain absorbing boundary conditions have to be employed to prevent reflection of the radiation. In this paper we show how the divergence preserving ADI scheme has to be formulated in perfectly matched layers (PML) and compare the performance in several scenarios.Comment: 8 pages, 6 figure

Accurate Permittivity Measurements for Microwave Imaging via Ultra-Wideband Removal of Spurious Reflectors

The use of microwave imaging is becoming more prevalent for detection of interior hidden defects in manufactured and packaged materials. In applications for detection of hidden moisture, microwave tomography can be used to image the material and then perform an inverse calculation to derive an estimate of the variability of the hidden material, such internal moisture, thereby alerting personnel to damaging levels of the hidden moisture before material degradation occurs. One impediment to this type of imaging occurs with nearby objects create strong reflections that create destructive and constructive interference, at the receiver, as the material is conveyed past the imaging antenna array. In an effort to remove the influence of the reflectors, such as metal bale ties, research was conducted to develop an algorithm for removal of the influence of the local proximity reflectors from the microwave images. This research effort produced a technique, based upon the use of ultra-wideband signals, for the removal of spurious reflections created by local proximity reflectors. This improvement enables accurate microwave measurements of moisture in such products as cotton bales, as well as other physical properties such as density or material composition. The proposed algorithm was shown to reduce errors by a 4:1 ratio and is an enabling technology for imaging applications in the presence of metal bale ties

Identifying factors of risk management for the construction industry

Abstract: Delays and cost overruns are recurrent in construction projects. Risk management (RM) has been developed to curtain risks associated with construction projects. However, there is no consensus of what factors should constitute RM for construction projects. Therefore, this paper scrutinises preceding studies on the theme of RM and establish core risk management factors (RMFs) that are indispensable to make the concept valuable in the construction industry (CI). A literature search related to RM was conducted in order to identify common RMF. It was indicated that there is still misunderstanding and disagreement over the factors that should constitute RM in construction. However, the RMFs of organisational environment, defining objectives, resource requirement, risk measurement, risk identification, risk assessment, risk response and action planning, communication, monitoring, review and continuous improvement dominate the literature. Identifying RMF that can effortlessly be understood and implemented will contribute to ameliorating the current RM status and boosting the body of knowledge