Performance Portability Study of Linear Algebra Kernels in OpenCL

The performance portability of OpenCL kernel implementations for common memory bandwidth limited linear algebra operations across different hardware generations of the same vendor as well as across vendors is studied. Certain combinations of kernel implementations and work sizes are found to exhibit good performance across compute kernels, hardware generations, and, to a lesser degree, vendors. As a consequence, it is demonstrated that the optimization of a single kernel is often sufficient to obtain good performance for a large class of more complicated operations.Comment: 11 pages, 8 figures, 2 tables, International Workshop on OpenCL 201

Integration of an SAP transport control system in a simulation environment to support decisions in operational management

Digital twins enable the digital representation of physical systems and provide comprehensive modelling and analysis capabilities. An online data exchange between the Digital twin and SAP is feasible, through integration of a transport control systems (SAP) via RESTful API. This interface allows decision making in resource allocation and furthermore the adaptation of the digital model if the real system changes. Despite the associated challenges in terms of data synchronisation, the integration has benefits such as a reduction in modelling effort and an increase in the lifetime of the digital twin. In the context of this work, the design of the interface between the simulation software and a SAP transport control system via RESTful API is described

A model for hot-carrier degradation in nLDMOS transistors based on the exact solution of the Boltzmann transport equation versus the drift-diffusion scheme

Abstract-We present two schemes for carrier transport treatment to be used with our hot-carrier degradation (HCD) model. The first version relies on an exact solution of the Boltzmann transport equation (BTE) by means of the spherical harmonics expansion (SHE) method, whereas the second one uses a simplified drift-diffusion (DD) scheme to avoid the computationally expensive SHE approach. We use both versions of the model to simulate the change of the characteristics of an nLDMOS transistor subjected to hot-carrier stress and compare these theoretical degradation traces with the experimental ones. The similarity in the results of the SHE-and DD-based models together with the flexibility of the latter approach makes it attractive for fast and predictive HCD simulations for LDMOS devices

Remodeling of the chromatin structure of the facioscapulohumeral muscular dystrophy (FSHD) locus and upregulation of FSHD-related gene 1 (FRG1) expression during human myogenic differentiation

<p>Abstract</p> <p>Background</p> <p>Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant neuromuscular disorder associated with the partial deletion of integral numbers of 3.3 kb D4Z4 DNA repeats within the subtelomere of chromosome 4q. A number of candidate FSHD genes, adenine nucleotide translocator 1 gene (<it>ANT1</it>), FSHD-related gene 1 (<it>FRG1</it>), <it>FRG2 </it>and <it>DUX4c</it>, upstream of the D4Z4 array (FSHD locus), and double homeobox chromosome 4 (<it>DUX4</it>) within the repeat itself, are upregulated in some patients, thus suggesting an underlying perturbation of the chromatin structure. Furthermore, a mouse model overexpressing <it>FRG1 </it>has been generated, displaying skeletal muscle defects.</p> <p>Results</p> <p>In the context of myogenic differentiation, we compared the chromatin structure and tridimensional interaction of the D4Z4 array and <it>FRG1 </it>gene promoter, and <it>FRG1 </it>expression, in control and FSHD cells. The <it>FRG1 </it>gene was prematurely expressed during FSHD myoblast differentiation, thus suggesting that the number of D4Z4 repeats in the array may affect the correct timing of <it>FRG1 </it>expression. Using chromosome conformation capture (3C) technology, we revealed that the <it>FRG1 </it>promoter and D4Z4 array physically interacted. Furthermore, this chromatin structure underwent dynamic changes during myogenic differentiation that led to the loosening of the <it>FRG1</it>/4q-D4Z4 array loop in myotubes. The <it>FRG1 </it>promoter in both normal and FSHD myoblasts was characterized by H3K27 trimethylation and Polycomb repressor complex binding, but these repression signs were replaced by H3K4 trimethylation during differentiation. The D4Z4 sequences behaved similarly, with H3K27 trimethylation and Polycomb binding being lost upon myogenic differentiation.</p> <p>Conclusion</p> <p>We propose a model in which the D4Z4 array may play a critical chromatin function as an orchestrator of <it>in cis </it>chromatin loops, thus suggesting that this repeat may play a role in coordinating gene expression.</p

Impaired CK1 Delta Activity Attenuates SV40-Induced Cellular Transformation In Vitro and Mouse Mammary Carcinogenesis In Vivo

Simian virus 40 (SV40) is a powerful tool to study cellular transformation in vitro, as well as tumor development and progression in vivo. Various cellular kinases, among them members of the CK1 family, play an important role in modulating the transforming activity of SV40, including the transforming activity of T-Ag, the major transforming protein of SV40, itself. Here we characterized the effects of mutant CK1δ variants with impaired kinase activity on SV40-induced cell transformation in vitro, and on SV40-induced mammary carcinogenesis in vivo in a transgenic/bi-transgenic mouse model. CK1δ mutants exhibited a reduced kinase activity compared to wtCK1δ in in vitro kinase assays. Molecular modeling studies suggested that mutation N172D, located within the substrate binding region, is mainly responsible for impaired mutCK1δ activity. When stably over-expressed in maximal transformed SV-52 cells, CK1δ mutants induced reversion to a minimal transformed phenotype by dominant-negative interference with endogenous wtCK1δ. To characterize the effects of CK1δ on SV40-induced mammary carcinogenesis, we generated transgenic mice expressing mutant CK1δ under the control of the whey acidic protein (WAP) gene promoter, and crossed them with SV40 transgenic WAP-T-antigen (WAP-T) mice. Both WAP-T mice as well as WAP-mutCK1δ/WAP-T bi-transgenic mice developed breast cancer. However, tumor incidence was lower and life span was significantly longer in WAP-mutCK1δ/WAP-T bi-transgenic animals. The reduced CK1δ activity did not affect early lesion formation during tumorigenesis, suggesting that impaired CK1δ activity reduces the probability for outgrowth of in situ carcinomas to invasive carcinomas. The different tumorigenic potential of SV40 in WAP-T and WAP-mutCK1δ/WAP-T tumors was also reflected by a significantly different expression of various genes known to be involved in tumor progression, specifically of those involved in wnt-signaling and DNA repair. Our data show that inactivating mutations in CK1δ impair SV40-induced cellular transformation in vitro and mouse mammary carcinogenesis in vivo