Modeling Temporal Evidence from External Collections

Newsworthy events are broadcast through multiple mediums and prompt the crowds to produce comments on social media. In this paper, we propose to leverage on this behavioral dynamics to estimate the most relevant time periods for an event (i.e., query). Recent advances have shown how to improve the estimation of the temporal relevance of such topics. In this approach, we build on two major novelties. First, we mine temporal evidences from hundreds of external sources into topic-based external collections to improve the robustness of the detection of relevant time periods. Second, we propose a formal retrieval model that generalizes the use of the temporal dimension across different aspects of the retrieval process. In particular, we show that temporal evidence of external collections can be used to (i) infer a topic's temporal relevance, (ii) select the query expansion terms, and (iii) re-rank the final results for improved precision. Experiments with TREC Microblog collections show that the proposed time-aware retrieval model makes an effective and extensive use of the temporal dimension to improve search results over the most recent temporal models. Interestingly, we observe a strong correlation between precision and the temporal distribution of retrieved and relevant documents.Comment: To appear in WSDM 201

DC House Smart Pathway Lighting System

The Student Experimental Farm (SEF) is a two-acre site where students are able to create projects and experiments. It is also the location of the DC House project, a house with electricity provided by DC power as opposed to the traditional AC power. The motive of the DC house project is to provide affordable and renewable electricity for people living in remote areas where ac power grids are not available. Currently, the SEF does not have any lighting, so students would have to work in the dark after the sun sets. By creating a smart lighting system for the pathway towards the DC House, students working at the DC House will be able to work on their projects beyond daytime hours. The system will utilize DC power and turn on automatically when motion is detected. This lighting method will then save energy as the lights will only turn on momentarily as students pass by. With the ideals of the DC House in mind, the smart pathway lighting system not only saves energy, but it also will show the capabilities of a DC system providing proper lighting for communities with no access to an AC grid. The system was successfully implemented and installed. With expected conditions, power consumption requirements were met when system was both off and on

Defence diplomacy: is the game worth the candle?

Few defence topics have been as prominent or invested with as much optimism in recent years as defence diplomacy. This paper has been created to explore the issue and help guide policymakers. Foreword Few Defence topics have been as prominent or invested with as much optimism in recent years as defence diplomacy (also called military diplomacy or defence engagement). In response to the growing security challenges of Asia, scholars, policymakers and practitioners have looked for ways to build confidence, decrease the risk and impact of accidents and encourage peaceful dispute resolution. Defence diplomacy, namely the practice of military and defence officials engaging their overseas counterparts, is increasingly regarded as a vital way to achieve these aims. Given the importance of this topic, a special Centre of Gravity paper has been created to explore the issue and help guide policymakers. This edition features six short papers, each with a different take and policy recommendation. The authors were asked the same question ‘Is the game worth the candle?’ and while their answers focus largely on Australia there are lessons and implications from their findings for the entire region. Brendan Taylor, the head of the Strategic & Defence Studies Centre begins the special edition calling for a stocktake of current efforts, in a bid to understand what has worked and what resources it requires. He is joined by two colleagues, John Blaxland who argues strongly in favour of an expanded defence diplomacy program and Hugh White who urges caution about the strategic influence of the practice. To complement these views, Nick Bisley, Executive Director La Trobe Asia, highlights the need for realistic ambitions. Lieutenant General (Ret.) Peter Leahy draws on his distinguished career in the ADF to detail how defence diplomacy occurs in practice and why it matters. Finally, See Seng Tan, Deputy Director of the Institute of Defence and Strategic Studies in Singapore provides a regional perspective on Australia’s defence diplomacy. The authors of these papers don’t agree with each other, and that was precisely why they were invited to contribute. But some common themes are clear. Such as the need for a clear —and public — strategy along with integrating defence diplomacy into the efforts of other parts of government. Together these six papers provide insight into the practice and potential of defence diplomacy. This special edition also marks a re-launch of the Centre of Gravity Series. While some of the design may change, the focus remains the same: inviting some of the best analysts from Australia and around the world to provide short, accessible papers on the key questions facing Australian strategic affairs

Of rodents and primates: Time-variant gain in drift-diffusion decision models

Sequential sampling models of decision-making involve evidence accumulation over time and have been successful in capturing choice behaviour. A popular model is the drift-diffusion model (DDM). To capture the finer aspects of choice reaction times (RTs), time-variant gain features representing urgency signals have been implemented in DDM that can exhibit slower error RTs than correct RTs. However, time-variant gain is often implemented on both DDM’s signal and noise features, with the assumption that increasing gain on the drift rate (due to urgency) is similar to DDM with collapsing decision bounds. Hence, it is unclear whether gain effects on just the signal or noise feature can lead to different choice behaviour. This work presents an alternative DDM variant, focusing on the implications of time-variant gain mechanisms, constrained by model parsimony. Specifically, using computational modelling of choice behaviour of rats, monkeys and humans, we systematically showed that time-variant gain only on the DDM’s noise was sufficient to produce slower error RTs, as in monkeys, while time-variant gain only on drift rate leads to faster error RTs, as in rodents. We also found minimal effects of time-variant gain in humans. By highlighting these patterns, this study underscores the utility of group-level modelling in capturing general trends and effects consistent across species. Thus, time-variant gain on DDM’s different components can lead to different choice behaviour, shed light on the underlying time-variant gain mechanisms for different species, and can be used for systematic data fitting

VeriGen: A Large Language Model for Verilog Code Generation

In this study, we explore the capability of Large Language Models (LLMs) to automate hardware design by generating high-quality Verilog code, a common language for designing and modeling digital systems. We fine-tune pre-existing LLMs on Verilog datasets compiled from GitHub and Verilog textbooks. We evaluate the functional correctness of the generated Verilog code using a specially designed test suite, featuring a custom problem set and testing benches. Here, our fine-tuned open-source CodeGen-16B model outperforms the commercial state-of-the-art GPT-3.5-turbo model with a 1.1% overall increase. Upon testing with a more diverse and complex problem set, we find that the fine-tuned model shows competitive performance against state-of-the-art gpt-3.5-turbo, excelling in certain scenarios. Notably, it demonstrates a 41% improvement in generating syntactically correct Verilog code across various problem categories compared to its pre-trained counterpart, highlighting the potential of smaller, in-house LLMs in hardware design automation.Comment: arXiv admin note: text overlap with arXiv:2212.1114

Dictionary Learning under Symmetries via Group Representations

The dictionary learning problem can be viewed as a data-driven process to learn a suitable transformation so that data is sparsely represented directly from example data. In this paper, we examine the problem of learning a dictionary that is invariant under a pre-specified group of transformations. Natural settings include Cryo-EM, multi-object tracking, synchronization, pose estimation, etc. We specifically study this problem under the lens of mathematical representation theory. Leveraging the power of non-abelian Fourier analysis for functions over compact groups, we prescribe an algorithmic recipe for learning dictionaries that obey such invariances. We relate the dictionary learning problem in the physical domain, which is naturally modelled as being infinite dimensional, with the associated computational problem, which is necessarily finite dimensional. We establish that the dictionary learning problem can be effectively understood as an optimization instance over certain matrix orbitopes having a particular block-diagonal structure governed by the irreducible representations of the group of symmetries. This perspective enables us to introduce a band-limiting procedure which obtains dimensionality reduction in applications. We provide guarantees for our computational ansatz to provide a desirable dictionary learning outcome. We apply our paradigm to investigate the dictionary learning problem for the groups SO(2) and SO(3). While the SO(2)-orbitope admits an exact spectrahedral description, substantially less is understood about the SO(3)-orbitope. We describe a tractable spectrahedral outer approximation of the SO(3)-orbitope, and contribute an alternating minimization paradigm to perform optimization in this setting. We provide numerical experiments to highlight the efficacy of our approach in learning SO(3)-invariant dictionaries, both on synthetic and on real world data.Comment: 29 pages, 2 figure

Further evidence for the involvement of EFL1 in a Shwachman-Diamond-like syndrome and expansion of the phenotypic features.

Recent evidence has implicated EFL1 in a phenotype overlapping Shwachman-Diamond syndrome (SDS), with the functional interplay between EFL1 and the previously known causative gene SBDS accounting for the similarity in clinical features. Relatively little is known about the phenotypes associated with pathogenic variants in the EFL1 gene, but the initial indication was that phenotypes may be more severe, when compared with SDS. We report a pediatric patient who presented with a metaphyseal dysplasia and was found to have biallelic variants in EFL1 on reanalysis of trio whole-exome sequencing data. The variant had not been initially reported because of the research laboratory's focus on de novo variants. Subsequent phenotyping revealed variability in her manifestations. Although her metaphyseal abnormalities were more severe than in the original reported cohort with EFL1 variants, the bone marrow abnormalities were generally mild, and there was equivocal evidence for pancreatic insufficiency. Despite the limited number of reported patients, variants in EFL1 appear to cause a broader spectrum of symptoms that overlap with those seen in SDS. Our report adds to the evidence of EFL1 being associated with an SDS-like phenotype and provides information adding to our understanding of the phenotypic variability of this disorder. Our report also highlights the value of exome data reanalysis when a diagnosis is not initially apparent

Beryllium and Alpha-Element Abundances in a Large Sample of Metal-Poor Stars

The light elements, Li, Be, and B, provide tracers for many aspects of astronomy including stellar structure, Galactic evolution, and cosmology. We have taken spectra of Be in 117 metal-poor stars ranging in metallicity from [Fe/H] = -0.5 to -3.5 with Keck I + HIRES at a resolution of 42,000 and signal-to-noise ratios of near 100. We have determined the stellar parameters spectroscopically from lines of Fe I, Fe II, Ti I and Ti II. The abundances of Be and O were derived by spectrum synthesis techniques, while abundances of Fe, Ti, and Mg were found from many spectral line measurements. There is a linear relationship between [Fe/H] and A(Be) with a slope of +0.88 +-0.03 over three orders of magnitude in [Fe/H]. We fit the relationship between A(Be) and [O/H] with both a single slope and with two slopes. The relationship between [Fe/H] and [O/H] seems robustly linear and we conclude that the slope change in Be vs. O is due to the Be abundance. Although Be is a by-product of CNO, we have used Ti and Mg abundances as alpha-element surrogates for O in part because O abundances are rather sensitive to both stellar temperature and surface gravity. We find that A(Be) tracks [Ti/H] very well with a slope of 1.00 +-0.04. It also tracks [Mg/H] very well with a slope of 0.88 +-0.03. We find that there are distinct differences in the relationships of A(Be) and [Fe/H] and of A(Be) and [O/H] for our dissipative stars and our accretive stars. We suggest that the Be in the dissipative stars was primarily formed by GCR spallation and Be in the accretive stars was formed in the vicinity of SN II.Comment: Accepted for Ap.J. Nov. 10, 2011, v. 741 70 pages, 27 figures, 5 table

Defence Diplomacy: Is the Game Worth the Candle?

Few Defence topics have been as prominent or invested with as much optimism in recent years as defence diplomacy. This special Centre of Gravity paper has been created to explore the issue and help guide policymakers. It features contributions from 6 authors including Brendan Taylor, John Blaxland, Hugh White, Nick Bisley, Peter Leahy and See Seng Tan