The original version of this paper unfortunately contained errors. In Abstract, " 24.7 mg kg −1 " should be " 20.7 mg kg −1 in 2006 " .
Synthetic nitrogen (N) fertilizer has played a key role in enhancing food production and keeping half of the world's population adequately fed. However, decades of N fertilizer overuse in many parts of the world have contributed to soil, water, and air pollution; reducing excessive N losses and emissions is a central environmental challenge in the 21st… (More)
Dynamic optimization has the potential to adapt the program's behavior at run-time to deliver performance improvements over static optimization. Dynamic optimization systems usually perform their optimization in series with the application's execution. This incurs overhead which reduces the benefit of dynamic optimization, and prevents some aggressive… (More)
Speculative precomputation enables effective cache prefetching for even irregular memory access behavior, by using an alternate thread on a multithreaded or multi-core architecture. This paper describes a system that constructs and runs precomputation based prefetching threads via event-driven dynamic optimization. Precomputation threads are dynamically… (More)
Software prefetching has been demonstrated as a powerful technique to tolerate long load latencies. However, to be effective, prefetching must target the most critical (frequently missing) loads, and prefetch them sufficiently far in advance. This is difficult to do correctly with a static optimizer, because locality characteristics and cache latencies vary… (More)
Two types of bipolar resistance switching with eightwise and counter eightwise polarities are observed to coexist in Au/SrTiO3/Ti memory cells. These two types of switching can be induced by different defect distributions which are activated by controlling the electric process. The analyses of I-V and C-V data reveal that the resistance switching with… (More)
The Na0.5Bi0.5TiO3(NBT) thin films sandwiched between Au electrodes and fluorine-doped tin oxide (FTO) conducting glass were deposited using a sol-gel method. Based on electrochemical workstation measurements, reproducible resistance switching characteristics and negative differential resistances were obtained at room temperature. A local impedance… (More)
In web spam detection, we propose a new semi-supervised learning algorithm named HFSSL (harmonic functions based semi-supervised learning). In our method, labeled and unlabeled web pages are represented as vertices in a weighted graph. The learning problem is then modeled as a Gaussian random field on this graph, where the mean of the field is characterized… (More)