Invariance Matters: Exemplar Memory for Domain Adaptive Person Re-identification

This paper considers the domain adaptive person re-identification (re-ID) problem: learning a re-ID model from a labeled source domain and an unlabeled target domain. Conventional methods are mainly to reduce feature distribution gap between the source and target domains. However, these studies largely neglect the intra-domain variations in the target domain, which contain critical factors influencing the testing performance on the target domain. In this work, we comprehensively investigate into the intra-domain variations of the target domain and propose to generalize the re-ID model w.r.t three types of the underlying invariance, i.e., exemplar-invariance, camera-invariance and neighborhood-invariance. To achieve this goal, an exemplar memory is introduced to store features of the target domain and accommodate the three invariance properties. The memory allows us to enforce the invariance constraints over global training batch without significantly increasing computation cost. Experiment demonstrates that the three invariance properties and the proposed memory are indispensable towards an effective domain adaptation system. Results on three re-ID domains show that our domain adaptation accuracy outperforms the state of the art by a large margin. Code is available at: https://github.com/zhunzhong07/ECNComment: To appear in CVPR 201

Estimating Chlorophyll-A Concentration in a Freshwater Lake Using Landsat 8 Imagery

Numerous studies suggest that chlorophyll-a in waters can be measured using Landsat TM/ETM imagery but the feasibility of newly launched Landsat 8 with Operational Land Imager (OLI) on board is still being tested. Jordan Lake is one of the most eutrophic reservoirs in North Carolina, U.S and there is a great need to monitor the spatial distribution of chlorophyll-a in this freshwater lake for better water quality management. The purpose of this study was to examine the applicability of using Landsat 8 imagery to estimate and map chlorophyll-a concentration in Jordan Lake. In this study, the relationship between the reflectance value of an individual OLI band and in situ chlorophyll-a concentration was examined to identify bands sensitive to chlorophyll-a. We also investigated the performance of ratio-based spectral indices to retrieve chlorophyll-a concentrations in Jordan Lake. Two optimal linear equations were developed to model the relationship between ratio-based spectral index and in situ chlorophyll-a concentration in Jordan Lake for different seasons. There was a significant correlation between the spectral index derived from Landsat 8 imagery and chlorophyll-a concentration for Jordan Lake in summer and fall 2013. Spatial distribution of chlorophyll-a concentration in the Jordan Lake was successfully mapped using Landsat 8 imagery for two seasons in 2013. Despite the limitation of this work, our findings suggest that Landsat 8 imagery can be used to estimate chlorophyll-a concentration in fresh waters and it is promising to estimate and map chlorophyll-a concentration in freshwater lakes. Keywords: Chlorophyll-a, Spectral inde

Many-body dynamics of a Bose system with attractive interactions on a ring

We investigate the many-body dynamics of an effectively attractive one-dimensional Bose system confined in a toroidal trap. The mean-field theory predicts that a bright-soliton state will be formed when increasing the interparticle interaction over a critical point. The study of quantum many-body dynamics in this paper reveals that there is a modulation instability in a finite Bose system correspondingly. We show that Shannon entropy becomes irregular near and above the critical point due to quantum correlations. We also study the dynamical behavior of the instability by exploring the momentum distribution and the fringe visibility, which can be verified experimentally by releasing the trapComment: 6 pages,5 figure

Plant and Animal Responses to Different Grazing Regimes on a Meadow Steppe in Northeast China

Grazing by domestic herbivores is often considered to be an essential factor governing grassland vegetation and animal production (Hodgson and Illius 1996). During recent decades, there is increasing interest as a fundamental interaction between plant-animal interface, especially for the simultaneous or interactive responses of plants and animals to grassland grazing regimes (Liu et al., 2015), which benefits on improving the efficiency of grazing or grassland resource management. To achieve sustainable animal productivity and maintain the stability of grasslands, farmers or stakeholders need to employ optimal grazing strategies or regimes based on practical grassland vegetation and environments. Unfortunately, up to date it remains unclear what grazing regime will favour animal production, and mitigate the grassland degradation resulted from long-term free grazing in the eastern areas of the Eurasian Steppe. For this study, we conducted a five-year grazing experiment to test how grazing intensity (mediate and heavy) interact with resting to impact on the performance of plants and animals in a meadow steppe, and estimate the effects of designed grazing regime in this region