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排序方式: 共有334条查询结果,搜索用时 15 毫秒
81.
Soyeon Bae Bjoern Reineking Michael Ewald Joerg Mueller 《International journal of remote sensing》2013,34(17):6469-6489
Light detection and ranging (lidar) is a useful tool for measuring three-dimensional habitat structure; hence, its use in habitat suitability models has been explored, both as a single resource and in combination with other remote-sensing techniques. Here, we evaluated the suitability of airborne lidar data in comparison with aerial photographs and field surveys for modelling the distribution of an endangered and cryptic forest species, the hazel grouse (Bonasa bonasia). The study was conducted in the Bavarian Forest National Park of southeast Germany. Subsequently, a prediction map for conservation planning was generated for a large area, which encompassed the National Park. We examined the utility of lidar data for generating a hazel grouse distribution model by using machine learning (boosted regression trees), and then compared the results to variables derived from field surveys and aerial photographs, both separately and in combination. The cross-validated discrimination ability of the model was slightly higher when using lidar data (area under the receiver operator characteristic curve (AUC), 0.79) compared to models using aerial photographs (AUC, 0.75) or field survey data (AUC, 0.78). The predictive performance consistently increased when combining the predictors from different sources, with an AUC of 0.86 being produced in the model combining all three data sources. The three data sources complemented one another, with each data source probably having an advantage at deriving one of three key aspects of the hazel grouse habitat, namely, vertically well-structured forest stands, horizontally mixed successional vegetation stages, and certain deciduous trees as food resources such as mountain ash (Sorbus aucuparia). In addition, the diverse lidar metrics might be applied to simultaneously characterize vertically and horizontally well-structured forest stands. We conclude that public available airborne lidar data are a viable source for creating habitat suitability maps for large areas and may have increased utility for detecting forest characteristics and valuable wildlife habitats. 相似文献
82.
Graham D.W. Hasler P.E. Chawla R. Smith P.D. 《IEEE transactions on circuits and systems. I, Regular papers》2007,54(6):1165-1176
We present a programmable, continuous-time bandpass filter that is extremely compact, power efficient, and can cover a wide range of frequencies (10 Hz-10 MHz). This capacitively coupled current conveyor (C 4) has a second-order bandpass transfer function and is capable of being used as a basic bandpass-filter element to create high-order filters. The use of floating-gate transistors helps to ease the difficulties of effectively utilizing G m-C filters by providing precise, programmable current sources that set the filter's time constants. Additionally, we provide an algorithmic design approach for constructing these bandpass filters to meet any given specifications. This bandpass filter is ideally suited to large filter-bank applications because of its small size and low-power demands. 相似文献
83.
Stavros Giaglis Chanchal Sur Chowdhury Shane Vontelin van Breda Maria Stoikou Andr N. Tiaden Douglas Daoudlarian Guenther Schaefer Andreas Buser Ulrich A. Walker Olav Lapaire Irene Hoesli Paul Hasler Sinuhe Hahn 《International journal of molecular sciences》2021,22(24)
Pregnancy is associated with elevated maternal levels of cell-free DNA of neutrophil extracellular trap (NET) origin, as circulatory neutrophils exhibit increased spontaneous NET formation, mainly driven by G-CSF and finely modulated by sex hormones. The postpartum period, on the other hand, involves physiological alterations consistent with the need for protection against infections and fatal haemorrhage. Our findings indicate that all relevant serum markers of neutrophil degranulation and NET release are substantially augmented postpartum. Neutrophil pro-NETotic activity in vitro is also upregulated particularly in post-delivery neutrophils. Moreover, maternal puerperal neutrophils exhibit a strong pro-NETotic phenotype, associated with increased levels of all key players in the generation of NETs, namely citH3, MPO, NE, and ROS, compared to non-pregnant and pregnant controls. Intriguingly, post-delivery NET formation is independent of G-CSF in contrast to late gestation and complemented by the presence of TF on the NETs, alterations in the platelet activity status, and activation of the coagulation cascade, triggered by circulating microparticles. Taken together, our results reveal the highly pro-NETotic and potentially procoagulant nature of postpartum neutrophils, bridging an overt immune activation with possible harmful thrombotic incidence. 相似文献
84.
Effect of water activity on growth and enterotoxin D production of Staphylococcus aureus 总被引:1,自引:0,他引:1
Four enterotoxin D-producing strains of Staphylococcus aureus, were cultured at 37 degrees C in brain heart infusion broth adjusted to various water activity (aw) levels by means of NaCl. For high cell inocula growth of all strains and enterotoxin D production were observed within 6 days at aw levels down to 0.86. 相似文献
85.
Hall T.S. Twigg C.M. Gray J.D. Hasler P. Anderson D.V. 《IEEE transactions on circuits and systems. I, Regular papers》2005,52(11):2298-2307
Field-programmable analog arrays (FPAAs) provide a method for rapidly prototyping analog systems. Currently available commercial and academic FPAAs are typically based on operational amplifiers (or other similar analog primitives) with only a few computational elements per chip. While their specific architectures vary, their small sizes and often restrictive interconnect designs leave current FPAAs limited in functionality and flexibility. For FPAAs to enter the realm of large-scale reconfigurable devices such as modern field-programmable gate arrays (FPGAs), new technologies must be explored to provide area-efficient accurately programmable analog circuitry that can be easily integrated into a larger digital/mixed-signal system. Recent advances in the area of floating-gate transistors have led to a core technology that exhibits many of these qualities, and current research promises a digitally controllable analog technology that can be directly mated to commercial FPGAs. By leveraging these advances, a new generation of FPAAs is introduced in this paper that will dramatically advance the current state of the art in terms of size, functionality, and flexibility. FPAAs have been fabricated using floating-gate transistors as the sole programmable element, and the results of characterization and system-level experiments on the most recent FPAA are shown. 相似文献
86.
N. L. Ewald G. Fairhurst M. Noisternig T. Soboll A. Yun‐Garcia I. Moreno 《International Journal of Satellite Communications and Networking》2012,30(2):88-97
The current signalling framework for Digital Video Broadcasting systems is based on MPEG‐2 encoded Program Specific Information and System Information tables that rely on the transport stream. It is expected that in the near future, this architecture will be replaced by one based on the Generic Stream Encapsulation protocol, paving the way for the convergence of DVB‐S2 broadcast transmission networks and IP infrastructure. This paper presents a new lightweight Generic Stream Signalling Transport Protocol, which can be used to realise a transmission system based only on the Generic Stream Encapsulation and that efficiently supports filtering of Program Specific Information and System Information tables. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
87.
Ozalevli E. Huang W. Hasler P.E. Anderson D.V. 《IEEE transactions on circuits and systems. I, Regular papers》2008,55(2):510-521
A reconfigurable implementation of distributed arithmetic (DA) for post-processing applications is described. The input of DA is received in digital form and its analog coefficients are set by using the floating-gate voltage references. The effect of the offset and gain errors on DA computational accuracy is analyzed, and theoretical results for the limitations of this design strategy are presented. This architecture is fabricated in a 0.5-mum CMOS process, and configured as a 16-tap finite impulse response (FIR) filter to demonstrate the reconfigurability and computational efficiency. The measurement results for comb, low-pass, and bandpass filters at 32/50-kHz sampling frequencies are presented. This implementation occupies around 1.125 mm2 of die area and consumes 16 mW of static power. The filter order can be increased at the cost of 0.011 mm2 of die area and 0.02 mW of power per tap. 相似文献
88.
Sukhvinder Pal Singh Zora Singh & Ewald E. Swinny 《International Journal of Food Science & Technology》2009,44(10):1973-1982
The effects of fruit maturation, harvest date, storage temperature, storage period and shelf life, on the concentrations of individual sugars and organic acids in Japanese plums were investigated. During fruit maturation in 'Amber Jewel' plums, sucrose concentration increased significantly from 101 days after full bloom (DAFB) to 1 week after commercial maturity (136 DAFB) with a non-significant change in the concentration of total organic acids and malic acid, the major organic acid. The changes in concentrations of sugars and organic acids during cold storage of 'Amber Jewel' plums harvested on 129 and 136 DAFB appeared to be independent of harvest date. Storage of 'Amber Jewel' plums at 5 °C accelerated the loss of sucrose and increased the concentrations of fructose and glucose from the 4th week of storage compared with those stored at 0 °C. 'Blackamber' plums did not undergo any significant increase in the total and individual sugars during 5 weeks storage and subsequent shelf-life of 8 days at 20 °C. Malic acid concentrations declined during storage from 3 weeks onwards with a further substantial loss during ripening at 20 °C. Maturation, harvest date, storage temperature, storage period and shelf-life affect the concentrations of sugars and organic acids in Japanese plums. 相似文献
89.
保护可编程逻辑设计免受攻击 过去,军事项目是设计盗窃行为的主要攻击目标。但如今,知识产权(IP)保护已成为主流商用产品开发人员所关心的主要问题,以及消费电子制造商关心的重要事项,因为伪造产品会侵占其市场份额, 相似文献
90.