Development of an automotive HID electronic ballast based microprocessor

Author name used in this publication: D. H. WangAuthor name used in this publication: K. W. E. ChengAuthor name used in this publication: P. DongAuthor name used in this publication: X. D. XueAuthor name used in this publication: K. DingAuthor name used in this publication: Y. B. CheAuthor name used in this publication: C. D. XuPower Electronics Research CentreRefereed conference paper2006-2007 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Offline Reinforcement Learning with Imbalanced Datasets

The prevalent use of benchmarks in current offline reinforcement learning (RL) research has led to a neglect of the imbalance of real-world dataset distributions in the development of models. The real-world offline RL dataset is often imbalanced over the state space due to the challenge of exploration or safety considerations. In this paper, we specify properties of imbalanced datasets in offline RL, where the state coverage follows a power law distribution characterized by skewed policies. Theoretically and empirically, we show that typically offline RL methods based on distributional constraints, such as conservative Q-learning (CQL), are ineffective in extracting policies under the imbalanced dataset. Inspired by natural intelligence, we propose a novel offline RL method that utilizes the augmentation of CQL with a retrieval process to recall past related experiences, effectively alleviating the challenges posed by imbalanced datasets. We evaluate our method on several tasks in the context of imbalanced datasets with varying levels of imbalance, utilizing the variant of D4RL. Empirical results demonstrate the superiority of our method over other baselines

High-frequency acousto-optic effects in Bragg reflectors

Picosecond acoustic interferometry was used to study the acousto-optic properties of a distributed Bragg reflector (DBR) manufactured from two immiscible polymers (cellulose acetate and polyvinylcarbyzole). Picosecond strain pulses were injected into the structure and changes in its reflectance were monitored as a function of time. The reflectance exhibited single-frequency harmonic oscillations as the strain pulse traversed the DBR. A transfer matrix method was used to model the reflectance of the DBR in response to interface modulation and photo-elastic effects. This work shows that photo-elastic effects can account for the acousto-optic response of DBRs with acoustically matched layers

Structure of hadron resonances with a nearby zero of the amplitude

We discuss the relation between the analytic structure of the scattering amplitude and the origin of an eigenstate represented by a pole of the amplitude.If the eigenstate is not dynamically generated by the interaction in the channel of interest, the residue of the pole vanishes in the zero coupling limit. Based on the topological nature of the phase of the scattering amplitude, we show that the pole must encounter with the Castillejo-Dalitz-Dyson (CDD) zero in this limit. It is concluded that the dynamical component of the eigenstate is small if a CDD zero exists near the eigenstate pole. We show that the line shape of the resonance is distorted from the Breit-Wigner form as an observable consequence of the nearby CDD zero. Finally, studying the positions of poles and CDD zeros of the KbarN-piSigma amplitude, we discuss the origin of the eigenstates in the Lambda(1405) region.Comment: 7 pages, 3 figures, v2: published versio

The global burden of fragility fractures – what are the differences, and where are the gaps

The current burden of fragility fractures is enormous, and it is set to increase rapidly in the coming decades as humankind enters a new demographic era. The purpose of this review is to consider, in different settings: • The human and economic toll of fragility fractures. • Risk factors for fragility fractures. • Current acute management of fragility fractures. • Current care gaps in both secondary and primary fracture prevention. A summary of global, regional, and national initiatives to improve the quality of care is provided, in addition to proposals for the research agenda. Systematic approaches to improve the acute care, rehabilitation and prevention of fragility fractures need to be developed and implemented rapidly and at scale in high-, middle- and low-income countries throughout the world. This must be an essential component of our response to the ageing of the global population during the remainder of the current United Nations – World Health Organization “Decade of Healthy Ageing”