No abstract

In recent years, hashing has attracted more and more attention owing to its superior capacity of low storage cost and high query efficiency in large-scale cross-modal retrieval. Benefiting from deep leaning, continuously compelling results in cross-modal retrieval community have been achieved. However, existing deep cross-modal hashing methods either rely on amounts of labeled information or have no ability to learn an accuracy correlation between different modalities. In this paper, we proposed Unsupervised coupled Cycle generative adversarial Hashing networks (UCH), for cross-modal retrieval, where outer-cycle network is used to learn powerful common representation, and inner-cycle network is explained to generate reliable hash codes. Specifically, our proposed UCH seamlessly couples these two networks with generative adversarial mechanism, which can be optimized simultaneously to learn representation and hash codes. Extensive experiments on three popular benchmark datasets show that the proposed UCH outperforms the state-of-the-art unsupervised cross-modal hashing methods.

No abstract

Vegetable fields in China are characterized with intensive fertilization and cultivation, and their net effect on the global warming deserves attention. Greenhouse gas fluxes were thus measured, using a static closed chamber method, over approximately 18 months in two typical subtropical vegetable fields with different soil types and contrasting soil properties. Five consecutive crops were planted in one field and four in the other. Intensive fertilization consistently stimulated soil N 2 O emission, while imposed complicated impact on soil respiration with CO 2 emission enhanced in one field and suppressed in the other field. The fertilizer-induced N 2 O emission factors (EFs) varied with individual crop phases and averaged 1.4 to 3.1% across the whole sampling period for different fields. The interaction of soil temperature and moisture could explain about 58% of the seasonal variation in the EFs. All the soils under different vegetable cropping systems were net sources of atmospheric radiative forcing and the net global warming potential over the entire study period ranged from 1,786 to 3,569 g CO 2 equivalence m -2 for fertilized soils with net CO 2 emission contributing 53 to 67% and N 2 O emission occupying the remaining 33 to 47%.