Extracting structural characteristics of herbaceous floodplain vegetation under leaf‐off conditions using airborne laser scanner data

Hydrodynamic models of river flow need detailed and accurate friction values as input. Friction values of floodplain vegetation are based on vegetation height and density. To map spatial patterns of floodplain vegetation structure, airborne laser scanning is a promising tool. In a test for the lower Rhine floodplain, vegetation height and density of herbaceous vegetation were measured in the field at 42 georeferenced plots of 200 m² each. Simultaneously, three airborne laser scanning (ALS) surveys were carried out in the same area resulting in three high resolution, first pulse, small‐footprint datasets. The laser data surveys differed in flying height, gain setting and laser diode age. Point density of the laser data varied between 10 and 75 points m^?2. Point heights relative to the DTM derived from the ALS data were used in all analyses. Laser points were labelled as either vegetation or ground using three different methods: (1) a fixed threshold value; (2) a flexible threshold value based on the inflection point in the point height distribution; and (3) using a Gaussian distribution to separate noise in the ground surface points from vegetation. Twenty‐one statistics were computed for each of the resulting vegetation‐point distributions, which were subsequently compared with field observations of vegetation height. Additionally, the percentage index (PI) was computed to relate density of vegetation points to hydrodynamic vegetation density. The vegetation height was best predicted by using the inflection method for labelling and the 95 percentile as a regressor (R ² = 0.74–0.88). Vegetation density was best predicted using the threshold method for labelling and the PI as a predictor (R ² = 0.51). The results of vegetation height prediction were found to depend on the combined effect of flying height, gain setting or laser diode age. The quality of the estimation of vegetation height and density is also affected by point density, for densities lower than 15 points m^?2. We conclude that high resolution ALS data allows to estimate vegetation height and density of herbaceous vegetation in winter condition, but field reference data remains necessary for calibration.     

Estimate of net primary productivity of aquatic vegetation of the Amazon floodplain using Radarsat and JERS‐1

Synthetic aperture radar images, combined with field measurements, were used to estimate net primary productivity (NPP) of aquatic vegetation in the lower Amazon. Input data for a NPP model are (i) the total biomass of aquatic vegetation, determined by radar imagery and field measurements and (ii) the area occupied by aquatic vegetation, determined from radar imagery. After correction for monthly biomass losses, the NPP of one growth cycle of aquatic vegetation was calculated in the image domain. The total net primary productivity of Hymenachne amplexicaules, the dominant aquatic vegetation in the area, was on average 19×10¹¹ g C yr^?1 for the entire area. Spatially, lower values of produced organic carbon (<900 g C m^?2 yr^?1) are confined to regions where the plants developed only in the beginning of the rising phase of the hydrological cycle. In general, values are higher (>5000 g C m^?2 yr^?1) in areas closer to the Amazon River where the availability and influence of nutrient‐rich water is greater.     

Reflectance of floodplain waterbodies using EO‐1 Hyperion data from high and receding flood periods of the Amazon River

The potential of Hyperion images acquired on September 2001 (receding flood period of the Amazon River) and June 2005 (high flood) was investigated for reflectance characterization of selected Amazon floodplain waterbodies using a linear spectral mixture model. The results show the ability of Hyperion to measure adequately the major variation in water reflectance spectral features in response to the annual flood pulse of the Amazon River. Mixture model fraction values were correlated with measured inorganic suspended solids (ISS) but not with chlorophyll (Chl) in the high flood period. Inspection of the fractions across the two images revealed variation in water composition. Small changes in ISS‐ and Chl‐bearing water fractions between the images indicated relatively stable spectral conditions for low (Tapajós River and Lake Juruparipucu) and high (Amazon River) turbidity waterbodies. Large changes indicated reflectance variation in some lakes when the water receded due to algal blooms (Lake Curumu) and sediment resuspension in shallow regions (Lake Aritapera). Although not all water constituents were modelled adequately for quantification purposes, spectral mixture modelling is still an interesting approach for spectral–temporal reflectance characterization of Amazonian floodplains with hyperspectral data.     

Made in China

人们都说":外来的和尚好念经",然而,当软件这一可塑性极强的产品在中国市场上遇到SaaS这一"外来和尚"的时候,似乎这本经并不好念。据了解,尽管被国外引为经典的SaaS模式在国内已经发展了近3年,可是在国外赢利效果相当不错的Salesforce.com     

bodied in sever

d jointly by the national laws,folk customs and morality,though the ways of regulation can vary in different countries or historical periods.laws about sex, sex laws, Foucault0贵州大学学报(社会科学版)Journal of Guizhou Uni     

Distance decay in spectral space in analysing ecosystem β‐diversity

The use of spectral distance for explaining the phenomenon of distance decay in species similarity between two sites (based on the niche difference model) is presented here. Distance decay is based on the first law of geography: ‘the similarity between two sites decays with increasing the distance between them’. From an ecological point of view, this could be expressed as: ‘the β‐diversity between two sites should increase with an increase in spatial distance’. Beta‐diversity is defined as the amount of turnover in species composition from one site to another; and it plays a key role in biodiversity management and conservation, as it allows the detection of spatial gradients that act functionally in determining the spatial variation in species composition. This work demonstrates how the celebrated distance decay pattern achieved by means of spatial distance can be attained even with spectral distance, measured on Landsat near‐infrared images. It is argued that spectral heterogeneity represents a good proxy of β‐diversity of an area, becoming a valuable tool in biodiversity characterization at regional and global scales.     

Equilibria in secure strategies in the Bertrand–Edgeworth duopoly

This paper analyzes the Bertrand–Edgeworth duopoly model using a solution concept of Equilibrium in Secure Strategies (EinSS), which describes cautious behavior in noncooperative games. The concept is suitable for studying games where the threats of other players represent an important factor in the decision-making process. We demonstrate that, in some cases where the Bertrand–Edgeworth price duopoly admits no Nash–Cournot equilibria, there exists a unique EinSS with both players choosing an identical equilibrium price lower than the monopoly price. The difference between these prices can be interpreted as an additional reduction in price that allows the players to secure themselves against the mutual threats of undercutting. We formulate and prove a criterion for the EinSS existence.     

Escaping ‘localisms’ in IT sourcing: tracing changes in institutional logics in an Italian firm

Organizations are limited in their choices by the institutional environment in which they operate. This is particularly true for IT sourcing decisions that go beyond cost considerations and are constrained by traditions, geographical location, and social networks. This article investigates how a company can disentangle itself from the constraints of the institutional environment. We do so drawing on a longitudinal case study of an Italian SME active in the steel industry that successfully changed its institutionally sound, but increasingly inefficient, IT sourcing practice. Our main result suggests that by attending steadily to institutional logics, organizations can become selective in how the institutional environment influences them and act more purposefully in their decisions. In particular, through the creation of companywide IT management competencies and targeted hiring practices, organizations can strike a balance between the different institutional logics guiding IT sourcing decisions and eventually shift from the dominant logic of localism to a logic of market efficiency. This change does not depend from a choice but rather builds on a process through which IT management competences are slowly integrated in the organization.     

Inhibition in superior colliculus neurons in a brightness discrimination task?

Simultaneous recordings were collected from between two and four buildup neurons from the left and right superior colliculi in rhesus monkeys in a simple two-choice brightness discrimination task. The monkeys were required to move their eyes to one of two response targets to indicate their decision. Neurons were identified whose receptive fields were centered on the response targets. The functional role of inhibition was examined by conditionalizing firing rate on a high versus low rate in target neurons 90 ms to 30 ms before the saccade and examining the firing rate in both contralateral and ipsilateral neurons. Two models with racing diffusion processes were fit to the behavioral data, and the same analysis was performed on simulated paths in the diffusion processes that have been found to represent firing rate. The results produce converging evidence for the lack of a functional role for inhibition between neural populations corresponding to the two decisions.     

vance in Soil Dynami

cs and Geotechnical Earthquake EngineeringLiu Hanlong Yu Xiangjuan(Research Institute of Geotechnical Engineering, Hohai University, Nanjing 210098)The recent advance in dynamic constitutive model and dynamic analysis for soil mass is reviewed in the paper, and the researches on the elastic plastic model and dynamic elastic     

Adaptive workload allocation in query processing in autonomous heterogeneous environments

The increasing prevalence of networked storage and computational resources, along with middleware for managing resource access and sharing, raises the prospect that queries can be run over resources obtained on demand, rather than on dedicated infrastructures. However, the movement of query processing into non-dedicated environments means that it is necessary to take account of the partial information and unstable conditions that characterise autonomous, shared, distributed settings. Thus, query processing on grid platforms needs to be adaptive, revising evaluation strategies at query runtime in response to the evolving environment, such as changes to machine load and availability. To address this challenge, adaptive techniques are described that: (i) balance load across plan partitions supporting intra-operator parallelism; (ii) remove bottlenecks in pipelined plans supporting inter-operator parallelism; and (iii) combine the two aforementioned techniques. The approach has been empirically evaluated in a grid-enabled adaptive query processor.     

Thinking in Bruce Eckel

从1986年至今,Bruce Eckel已经发表了超过150篇计算机技术文章,出版了6本书(其中4本是关于C++的),并且在全世界做了数百次演讲。他是《Thinking in Java》、《Thinking in C++》、《C++ Inside ＆ Out》、     

至in影音组合

外面看电影固然很爽，但身为《Geek》挑片子总该有点底线，可是电影院放什么咱们控制不了，而电影院又几乎都是些没底线的主。咱们还是在家里备一套常用组合以满足咱们那孤傲的选择吧。     

Structures Definable in Polymorphism

Encodings in polymorphism with finite product types are considered.These encodings are given in terms of I-algebras.They have th property that the ground terms are precisely the closed normal terms of the encoded types.The proof of a well-known result is transplanted to the setting and it is shown why weak recursion is admissible.The paper also shows how to carry out the dual encodings using the existential quantifier.     

e in The Sound

the FuryGENG Chong-huan(Foreign Languages College, Hebei Teachers University, Shijiazhuang Hebei 050091,China)The southern American modern writer, the winner of the Nobe     

Key Issues in Electronic Commerce in Today’s Global Information Infrastructure

This paper presents an overview of some of the key issues which have emerged in recent years surrounding the growth and application of e-commerce in the global information infrastructure (GII). Increased access to the Internet, the Internet as a strategic resource for business, trust and security issues surrounding e-commerce, and calls for a regulatory and legal framework to protect buyers and sellers, are four critical areas that need to be addressed by industry, government and the individual. In attempting to synthesise some of the contemporary key issues in e-commerce, we conclude by suggesting that research into this subject must embrace both external and internal factors as this will engender a deeper understanding of the role of e-commerce in the so-called ‘knowledge-driven economy’.     

Is team training in briefings for surgical teams feasible in simulation?

We developed a module for surgical team training using briefings in simulated crisis scenarios and here we report preliminary findings. Nine surgical teams (34 trainees) participated in a pre-training simulation, followed by an interactive workshop on briefing and checklists, and then a post-training simulation. Both technical and non-technical skills were assessed via observation during simulations by expert trainers who provided feedback on performances at the end of simulation. Trainees also reported their attitudes to briefings and evaluated the training. Pre-training attitudes to briefing were positive, some of which improved post-training and trainees’ evaluation of the training was positive. Surgeons’ technical skill improved significantly post-training, but their decision-making skill was rated lower than other non-technical skills, compared to other trainees. The training did not appear to greatly improve non-technical skill performance. Training surgical teams in simulation is feasible but much more work is needed on measurement development and training strategy to confirm its efficacy and utility.