Nearest Neighbor and Kernel Survival Analysis: Nonasymptotic Error Bounds and Strong Consistency Rates

We establish the first nonasymptotic error bounds for Kaplan-Meier-based nearest neighbor and kernel survival probability estimators where feature vectors reside in metric spaces. Our bounds imply rates of strong consistency for these nonparametric estimators and, up to a log factor, match an existing lower bound for conditional CDF estimation. Our proof strategy also yields nonasymptotic guarantees for nearest neighbor and kernel variants of the Nelson-Aalen cumulative hazards estimator. We experimentally compare these methods on four datasets. We find that for the kernel survival estimator, a good choice of kernel is one learned using random survival forests.Comment: International Conference on Machine Learning (ICML 2019

Factorizations of Matrices Over Projective-free Rings

An element of a ring $R$ is called strongly $J^{\#}$-clean provided that it can be written as the sum of an idempotent and an element in $J^{\#}(R)$ that commute. We characterize, in this article, the strongly $J^{\#}$-cleanness of matrices over projective-free rings. These extend many known results on strongly clean matrices over commutative local rings

Sustainability analysis of Chinese transport policy

Whilst the world economy is developed, the life and development of human beings have been threatened by the imbalance among environmental and ecological aspects. Thus sustainability is becoming increasingly the focus of various social fields. For most developing countries, a strategy with good sustainability for social development is of long-term significance to keep the economy in expansion. This paper first reviews the conceptual framework and up-to-date development of sustainability. Second, it reviews the current transport situation of China and its future demands. Third, the paper analyses transport policy from the viewpoints of energy consumption and environment pollution caused by transportation. It finally summarises suggestions for transport policy that China should consider in the future

Pressure deformation of tires using differential stiffness for triangular solid-of-revolution elements

The derivation is presented of the differential stiffness for triangular solid of revolution elements. The derivation takes into account the element rigid body rotation only, the rotation being about the circumferential axis. Internal pressurization of a pneumatic tire is used to illustrate the application of this feature

Phonological similarity effects in Cantonese word recognition

Two lexical decision experiments in Cantonese are described in which the recognition of spoken target words as a function of phonological similarity to a preceding prime is investigated. Phonological similaritv in first syllables produced inhibition, while similarity in second syllables led to facilitation. Differences between syllables in tonal and segmental structure had generally similar effects

The effect of correlation between demands on hierarchical forecasting

The forecasting needs for inventory control purposes are hierarchical. For SKUs in a product family or a SKU stored across different depot locations, forecasts can be made from the individual series’ history or derived top-down. Many discussions have been found in the literature, but it is not clear under what conditions one approach is better than the other. Correlation between demands has been identified as a very important factor to affect the performance of the two approaches, but there has been much confusion on whether positive or negative correlation. This paper summarises the conflicting discussions in the literature, argues that it is negative correlation that benefits the top-down or grouping approach, and quantifies the effect of correlation through simulation experiments