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Gaussian Process-based learning with new MCMC-based implementation of Wishart prior on correlation matrix

arXiv.org Machine Learning

Gaussian Process (GP) models are widely used as probabilistic models for nonlinear functions because they combine flexible function modelling with uncertainty quantification (Rasmussen and Williams, 2006; Williams, 1998; MacKay, 1992; Neal, 1995). Their predictive performance depends heavily on how kernel hyperparameters are learnt (Sundararajan and Keerthi, 2001). This becomes especially important in higher-dimensional multivariate settings, where many input-specific hyperparameters may be present and where only some inputs may contribute meaningful predictive structure (MacKay, 1992; Neal, 1995; Rasmussen and Williams, 2006; Linkletter et al., 2006; Paananen et al., 2019). In standard Bayesian formulations of GP learning, prior specification is usually imposed directly on kernel hyperparameters such as lengthscales, amplitude parameters, and noise terms (Rasmussen and Williams, 2006; Williams, 1998). This is natural from a modelling point of view, but it does not always give useful control over the covariance structure that those hyperparameters induce over the observed design points (Barnard et al., 2000; Gelman, 2006; Daniels and Kass, 1999; Huang and Wand, 2013). However, it is this induced covariance matrix that directly governs likelihood evaluation, numerical stability, and predictive behaviour (Rasmussen and Williams, 2006; Stein, 1999). 1


Companies Keep Slashing Employees' Benefits for the Worst Reasons

WIRED

Companies Keep Slashing Employees' Benefits for the Worst Reasons Workers are getting worse health care, parental leave, and retirement benefits, showing once and for all that your job doesn't love you back. Employee benefits are in the spotlight this week, and that's because of three recent stories about US companies cutting back on non-wage compensations for workers. A Texas tech consulting firm with a forgettable name--TTEC--suddenly became a lot more memorable when it suspended its discretionary 401(k) match program for 16,000 employees through at least the end of 2026. According to Business Insider, which viewed an internal TTEC memo, the company plans to invest in AI certifications, AI tools and training, and automation, among other things. The auditing and consulting giant Deloitte is also reportedly slashing benefits for some workers starting next year.


Callaway's new golf driver face combines titanium, carbon fiber, and a military-grade polymer found in an unlikely way

Popular Science

Gear Fitness Gear Callaway's new golf driver face combines titanium, carbon fiber, and a military-grade polymer found in an unlikely way Callaway's new Quantum drivers use the Tri-Force Face, a three-layer design bonding titanium and carbon fiber with a polymer the R&D team found in military research. More information Adding us as a Preferred Source in Google by using this link indicates that you would like to see more of our content in Google News results. The three-layered construction allows both carbon and titanium to shine. We may earn revenue from the products available on this page and participate in affiliate programs. Golf driver faces have been almost exclusively titanium for more than three decades, with some detours into carbon fiber .


Threshold Learning for Optimal Decision Making

Neural Information Processing Systems

Decision making under uncertainty is commonly modelled as a process of competitive stochastic evidence accumulation to threshold (the drift-diffusion model). However, it is unknown how animals learn these decision thresholds. We examine threshold learning by constructing a reward function that averages over many trials to Wald's cost function that defines decision optimality. These rewards are highly stochastic and hence challenging to optimize, which we address in two ways: first, a simple two-factor reward-modulated learning rule derived from Williams' REINFORCE method for neural networks; and second, Bayesian optimization of the reward function with a Gaussian process. Bayesian optimization converges in fewer trials than REINFORCE but is slower computationally with greater variance. The REINFORCE method is also a better model of acquisition behaviour in animals and a similar learning rule has been proposed for modelling basal ganglia function.




Ring Kills Flock Safety Deal After Super Bowl Ad Uproar

WIRED

Plus: Meta plans to add face recognition to its smart glasses, Jared Kushner named as part of whistleblower's mysterious national security complaint, and more. The widespread protests in Iran have exposed both Tehran's brutal tactics in the streets, where state authorities have killed thousands of demonstrators since early January, and extreme measures to block access to the global internet. As it has done repeatedly in the past, the Iranian regime cut off the country's residents from the global internet during the latest anti-government uprising. But it also shut down access to the country's intranet, known as the National Information Network, which new research found is becoming a mechanism of constant and pervasive surveillance that may ultimately be the only way Iranians can get online. The last remaining major nuclear weapons treaty between the United States and Russia just expired.


Infinite-FidelityCoregionalizationforPhysical Simulation

Neural Information Processing Systems

While existing approaches only model finite, discrete fidelities, in practice, the feasible fidelity choice is often infinite, which can correspond to a continuous mesh spacing orfinite element length.


Sparse or

Neural Information Processing Systems

Table evaluated hyperparameters Dataset Nd GPR |M| - - q() - - free-form Boston 506 13 3.049 Concrete 1030 8 4.864 Ener 768 8 0.441 WineRed1599 11 0.640 Yacht308 6 0.353