On the adequacy of untuned warmup for adaptive optimization

Adaptive optimization algorithms such as Adam are widely used in deep learning. The stability of such algorithms is often improved with a warmup schedule for the learning rate. Motivated by the difficulty of choosing and tuning warmup schedules, recent work proposes automatic variance rectification of Adam's adaptive learning rate, claiming that this rectified approach ("RAdam") surpasses the vanilla Adam algorithm and reduces the need for expensive tuning of Adam with warmup. In this work, we refute this analysis and provide an alternative explanation for the necessity of warmup based on the magnitude of the update term, which is of greater relevance to training stability. We then provide some "rule-of-thumb" warmup schedules, and we demonstrate that simple untuned warmup of Adam performs more-or-less identically to RAdam in typical practical settings. We conclude by suggesting that practitioners stick to linear warmup with Adam, with a sensible default being linear warmup over $2 / (1 - \beta_2)$ training iterations.Comment: AAAI 202

Conceptual framework of a Project Bank Account (PBA) blockchain payment application for the construction industry

The UK government published a guidance document in 2012 stipulating the use of project bank accounts (PBA) to promote fair and prompt payment practices in the construction industry. PBA utilises a project-specific escrow bank account to provide greater cash flow auditability and mitigate cascading payments down the supply chain. However, PBA is bureaucratic to manage and costly to set up. This paper will investigate whether blockchain can be used as an alternative system for executing PBA payments

Management and visualization of spatiotemporal information in GIS

Although Geographic Information Systems (GIS) have been recognised as the most advanced technology for the management of geospatial information, they are still unable to efficiently manage the temporal dimension. Originally this problem affeeted only the study and analysis of highly dynamic phenomena. Today's expansion of GIS technology, the ease to acquire and store geospatial data and the increased capacity of computing technologies to managc large amounl of data have contributed lo the propagation of this problem across the whole geospatial seclor. The extended use of GIS in decision-making processes is increasing the demand for tools able to manage and 10 analyse dynamic geospatial phenomena where the temporal dimension is crucial. The only temporal model available in commercial GIS packages is based on discretisation of temporal data. Changes are represented as a succession of snapshots. The dynamics and what happens between those stages are not registered. In addition, this approach presents severe problems due to unavoidable multiplication of data volume, abundant redundancies, loss in query efficiency and the impossibility of knowing when the exact timing of changes occurs. Since the late 1980s and particularly in the 1990s, researching the temporal changes and the conceptual and technological options available has been undertaken by the GIS and DBMS sectors. The primary objective of the research presented in this paper is the development of a model for the integration of temporal data with GIS. The method adopted to achieve this objective is based on the combination of Time Geography principies, its graphic language and dynamic segmentation techniques used in GIS. Past research has demonstrated that the difficulty to integrate time with GIS has its origin in the continuous nature of time. Dynamic segmentation in GIS network analysis has the potential to provide the means for a time-GIS integration in a continuous manner. Lifelines, one of the main Time geography's graphic language elements, has been modelled as a set of network segments where the dynamics in attribute information has been attached to different time segments rather than distance segments (for exampIe Euclidean or cost-based) as normally occurs in dynamic segmentation. This paper summarises initial findings of the project. These outcomes have the potential to improve the way the geospatial sector currently handles temporal information. However, the static nature of current GIS technology impedes an appropriate visualisation of dynamic temporal phenomena. To this effect, the paper also explores the possibilities offered by multimedia techniques as a complement to GIS capabilities

A novel expression platform for the production of diabetes-associated autoantigen human glutamic acid decarboxylase (hGAD65)

<p>Abstract</p> <p>Background</p> <p>Human glutamic acid decarboxylase 65 (hGAD65) is a key autoantigen in type 1 diabetes, having much potential as an important marker for the prediction and diagnosis of type 1 diabetes, and for the development of novel antigen-specific therapies for the treatment of type 1 diabetes. However, recombinant production of hGAD65 using conventional bacterial or mammalian cell culture-based expression systems or nuclear transformed plants is limited by low yield and low efficiency. Chloroplast transformation of the unicellular eukaryotic alga <it>Chlamydomonas reinhardtii </it>may offer a potential solution.</p> <p>Results</p> <p>A DNA cassette encoding full-length <it>hGAD65</it>, under the control of the <it>C. reinhardtii </it>chloroplast <it>rbc</it>L promoter and 5'- and 3'-UTRs, was constructed and introduced into the chloroplast genome of <it>C. reinhardtii </it>by particle bombardment. Integration of <it>hGAD65 </it>DNA into the algal chloroplast genome was confirmed by PCR. Transcriptional expression of <it>hGAD65 </it>was demonstrated by RT-PCR. Immunoblotting verified the expression and accumulation of the recombinant protein. The antigenicity of algal-derived hGAD65 was demonstrated with its immunoreactivity to diabetic sera by ELISA and by its ability to induce proliferation of spleen cells from NOD mice. Recombinant hGAD65 accumulated in transgenic algae, accounts for approximately 0.25–0.3% of its total soluble protein.</p> <p>Conclusion</p> <p>Our results demonstrate the potential value of <it>C. reinhardtii </it>chloroplasts as a novel platform for rapid mass production of immunologically active hGAD65. This demonstration opens the future possibility for using algal chloroplasts as novel bioreactors for the production of many other biologically active mammalian therapeutic proteins.</p

Quantum uniqueness

In the classical world one can construct two identical systems which have identical behavior and give identical measurement results. We show this to be impossible in the quantum domain. We prove that after the same quantum measurement two different quantum systems cannot yield always identical results, provided the possible measurement results belong to a non orthogonal set. This is interpreted as quantum uniqueness - a quantum feature which has no classical analog. Its tight relation with objective randomness of quantum measurements is discussed.Comment: Presented at 4th Feynman festival, June 22-26, 2009, in Olomouc, Czech Republic

Recombinational landscape of porcine X chromosome and individual variation in female meiotic recombination associated with haplotypes of Chinese pigs

<p>Abstract</p> <p>Background</p> <p>Variations in recombination fraction (θ) among chromosomal regions, individuals and families have been observed and have an important impact on quantitative trait loci (QTL) mapping studies. Such variations on porcine chromosome X (SSC-X) and on other mammalian chromosome X are rarely explored. The emerging assembly of pig sequence provides exact physical location of many markers, facilitating the study of a fine-scale recombination landscape of the pig genome by comparing a clone-based physical map to a genetic map. Using large offspring of F₁females from two large-scale resource populations (Large White ♂ × Chinese Meishan ♀, and White Duroc ♂ × Chinese Erhualian ♀), we were able to evaluate the heterogeneity in θ for a specific interval among individual F₁females.</p> <p>Results</p> <p>Alignments between the cytogenetic map, radiation hybrid (RH) map, genetic maps and clone map of SSC-X with the physical map of human chromosome X (HSA-X) are presented. The most likely order of 60 markers on SSC-X is inferred. The average recombination rate across SSC-X is of ~1.27 cM/Mb. However, almost no recombination occurred in a large region of ~31 Mb extending from the centromere to Xq21, whereas in the surrounding regions and in the Xq telomeric region a recombination rate of 2.8-3.3 cM/Mb was observed, more than twice the chromosome-wide average rate. Significant differences in θ among F₁females within each population were observed for several chromosomal intervals. The largest variation was observed in both populations in the interval <it>UMNP71-SW1943</it>, or more precisely in the subinterval <it>UMNP891-UMNP93</it>. The individual variation in θ over this subinterval was found associated with F₁females' maternal haplotypes (Chinese pig haplotypes) and independent of paternal haplotype (European pig haplotypes). The θ between <it>UMNP891 </it>and <it>UMNP93 </it>for haplotype 1122 and 4311 differed by more than fourteen-fold (10.3% vs. 0.7%).</p> <p>Conclusions</p> <p>This study reveals marked regional, individual and haplotype-specific differences in recombination rate on SSC-X. Lack of recombination in such a large region makes it impossible to narrow QTL interval using traditional fine-mapping approaches. The relationship between recombination variation and haplotype polymorphism is shown for the first time in pigs.</p

Pulsed-field magnetization of drilled bulk high-temperature superconductors: flux front propagation in the volume and on the surface

We present a method for characterizing the propagation of the magnetic flux in an artificially drilled bulk high-temperature superconductor (HTS) during a pulsed-field magnetization. As the magnetic pulse penetrates the cylindrical sample, the magnetic flux density is measured simultaneously in 16 holes by means of microcoils that are placed across the median plane, i.e. at an equal distance from the top and bottom surfaces, and close to the surface of the sample. We discuss the time evolution of the magnetic flux density in the holes during a pulse and measure the time taken by the external magnetic flux to reach each hole. Our data show that the flux front moves faster in the median plane than on the surface when penetrating the sample edge; it then proceeds faster along the surface than in the bulk as it penetrates the sample further. Once the pulse is over, the trapped flux density inside the central hole is found to be about twice as large in the median plane than on the surface. This ratio is confirmed by modelling