bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical characteristics of mineralized and nonmineralized rocks at the Restigouche deposit, Bathurst mining camp, New Brunswick
Authors: Katsube T J , Connell S , Scromeda N , Goodfellow W D , Best M E
Published: October 2013

Des mesures de la résistivité électrique ont été faites en laboratoire sur 20 échantillons principalement non minéralisés représentant les principaux lithotypes du camp minier de Bathurst, afin d'appuyer
l'interprétation des levés électromagnétiques aériens et en trous de sondage. Cette étude, portant sur les roches encaissantes non minéralisées, fait suite à des études semblables menées sur des roches minéralisées et non
minéralisées en provenance de plusieurs gisements de sulfures massifs présents dans cette région.
Les résultats révèlent que la résistivité électrique (rr) de ces échantillons varie de 0,3 à 56 000 Wúm, les valeurs inférieures étant décelées par les instruments électromagnétiques et les valeurs supérieures ne
l'étant pas. Les formations de fer et les roches sédimentaires carbonées montrent des anisotropies de résistivité de 25:1 à 300:1 et des valeurs de résistivité électrique (rr) de 12 à 90 Wúm, dans la direction de la conductivité, valeurs
qui ne sont pas décelables par la méthode électromagnétique. L'analyse des données au moyen du modèle de tri- polarisation laisse supposer que les minéraux conducteurs, tels que la magnétite, le graphite et le carbone, tapissent les pores dans les directions
à résistivité électrique faible, à l'exception d'un cas où la source s'avère être des fractures et non des plans de stratification.
Mapping the response of permafrost in Canada to climate warming
Authors: Smith S L , Burgess M M
Published: October 2013

The sensitivity of permafrost to climate warming is being examined as a contribution to a Geological Survey of Canada set of national syntheses on the impacts of climate change on active geological processes in Canada. Factors that influence the response of
permafrost to climate warming have been compiled to produce preliminary maps showing the relative response of the ground thermal regime and the relative magnitude of the impact of thaw. About 50% of the present permafrost region contains permafrost warmer than -2°C. The potential for thaw
and complete degradation of this warm permafrost is the greatest given current General Circulation Model predictions of air temperature warming of up to 4 and 5°C. The maps indicate that while the thermal response to an increase in air temperature would be relatively low for this warm
permafrost (due to the buffering effects of surface vegetation, snow, and organic covers), the impact of associated permafrost thaw would be relatively high.
Shale permeability characteristics
Authors: Katsube T J , Connell S
Published: October 2013

Permeability versus pressure data for 27 tight shale and compacted seafloor mud samples (28 measurements), obtained from several sedimentary basins in North America by the Geological Survey of Canada, have been analyzed in order to determine the shale
permeability-pressure characteristics. Tight shales are known to have some of the lowest permeabilities (10-23-10-19 m2) for rocks.
Results indicate that these samples can be divided into three groups, AA, BB, and CC, on the basis of their permeability (k) versus effective pressure (Pe) characteristics. Group AA is characterized by relatively large k values (1.0x10-20-1.6x10-18 m²) that decrease at moderate to rapid rates
with increasing Pe to 20-30 MPa where they level out. The group BB characteristics are similar, except that the k values are considerably smaller (1.0x10-22-1.0x10-19 m²). Group CC is characterized by large k values (3x10-19-1.6x10-18 m²) that decrease rapidly to very small k values
(3x10-22- 1.6x10-21 m²) at Pe=60 MPa. Group CC may represent a texture with a weakened pore framework.
Metamorphism of hydrothermally altered rocks
Authors: Froese E
Published: October 2013

In some metamorphosed volcanic belts, evidence of premetamorphic hydrothermal activity is preserved in the form of distinct metamorphic mineral assemblages. By considering the effect of metamorphism on rocks of various compositions, it is possible to deduce
premetamorphic mineral assemblages, some of which could be products of hydrothermal alteration. In some rocks, precursor minerals kaolinite, muscovite, and chlorite would indicate aluminous, potassic, and ferromagnesian alteration, respectively. The stabilities of alteration minerals can be related
to log fO2-pH conditions of the hydrothermal fluid.
Filling the Void: Defining Invasive Bedside Procedural Competency for Internal Medicine Residents
Authors: Lenchus Joshua D. , Carvalho Cristiane Mocelin , Ferreri Kaitlyn , Sanko Jill Steiner , Arheart Kristopher L. , Fitzpatrick Maureen , Issenberg S. Barry
Published: October 2013

Background

Residents perform invasive bedside procedures in most training programs. To date, there is no universal approach for determining competency and ensuring quality and safety of care.

Objective

We developed and implemented an assessment of central venous catheter insertion competency for internal medicine and internal medicine–pediatrics residents, using measurements for knowledge, skill, and attitude and linking them to procedural outcomes.

Methods

We conducted a cohort study of a 4-week, resident-run procedure service from July 2007 through June 2011 at a large academic medical center. Knowledge was assessed by using a written test, technical skill by using a checklist, and attitude by self- and supervisor assessments of residents' confidence and capability. Competence was defined as (1) a minimum written test score (70%); (2) a perfect checklist score; (3) a resident's self-assessed confidence and capability scores of 4 or 5 of 5; and (4) faculty rating of the resident's confidence and capability as 5 of 5. A composite success rate was based on procedural outcomes (eg, completed procedures, less than 3 forward needle passes, and complication rate) and was compared to the checklist scores.

Results

A total of 148 internal medicine and medicine–pediatrics residents inserted 639 catheters, and 53 (36%) achieved competence by the end of 4 weeks. Residents judged to be competent by checklist scores had a higher composite success rate than those deemed not competent.

Conclusions

Our multi-factorial criteria used to define central venous catheter insertion competency effectively discriminated between residents judged to be competent and those judged not competent, using data from procedural outcomes.
The Noble Enterprise of State Building: Reconsidering the Rise and Fall of the Modern State in Prussia and Poland
Authors: Wheeler Nicholas C.
Published: October 2013

Analysis of the state-building process in modern Europe rests upon the traditional assumption that monarchs were the central driving force behind the consolidation of power in the form of a centralized state. However, an alternative state-society account challenges the supposition that
monarchs were always the centralizing group in early modern society. The formation of the modern European state was ultimately shaped by the state-building strategies adopted by societal elites who possessed certain forms of social power. This alternative understanding of the state-building
process helps explain the puzzling developments surrounding the successful rise of Brandenburg-Prussia and the collapse of the Polish-Lithuanian Commonwealth during the early modern period.
International Norms, Domestic Politics, and the Death Penalty: Comparing Japan, South Korea, and Taiwan
Authors: Bae Sangmin
Published: October 2013

Why do countries with similar cultures and political institutions respond differently to international norms? The varied responses among East Asian democracies to the growing international movement to abolish the death penalty show that while Taiwan and South Korea have moved closer
to embracing the international human rights norm, Japan has been more resistant. The movement in Taiwan and South Korea toward a moratorium on capital punishment has little to do with public opinion, which generally favors retaining the death penalty. Rather, it reflects specific domestic
political contexts, especially the power and autonomy of the executive and the experience of a drastic regime change, that open the way for rethinking human rights norms.
Explaining Democracy's Origins: Lessons from South Asia
Authors: Tudor Maya
Published: October 2013

Why, upon the 1947 Partition of British India, was India able to establish a stable democracy while structurally similar Pakistan created an unstable autocracy? The differential strengths of India and Pakistan's independence movements directly account for their divergent democratization
trajectories. These movements were initially constructed to pursue historically conditioned class interests. An examination of these movements leads to a broader theory of democratic origins, which qualifies the prevailing notion that a country's democratization prospects can be attributed
to its levels of economic development or inequality.
Ice particles in the upper anvil regions of mid-latitude continental thunderstorms: the case for frozen-drop aggregates
Authors: Stith J. L. , Avallone L. , Bansemer A. , Basarab B. , Dorsi S. W. , Fuchs B. , Lawson R. P. , Rogers D. C. , Rutledge S. , Toohey D. W.
Published: October 2013

Abstract. This study examines the occurrence and morphology of frozen drop aggregates in thunderstorm anvils from the US Midwest and describes the environmental conditions where they are found. In situ airborne data collected in anvils using several particle imaging and sizing probes and bulk total water instrumentation during the 2012 Deep Convective Clouds and Chemistry Experiment are examined for the presence of frozen drop aggregates. These types of particles, especially chains of frozen drops, have been only rarely reported before and are hypothesized to aggregate due to electrical forces in the clouds. They were identified in nine of the anvil cases examined to-date, suggesting that they are common features in Midwestern anvils. High concentrations of individual frozen droplets occurred on the tops and edges of one particular set of anvils, while regions closer to the center and bottom of the anvils exhibited fewer frozen drops and more frozen drop aggregates. Bulk ice water content measurements across these anvils could only be explained by contributions from both small particles (frozen droplets) and large particles (large aggregates of frozen droplets). Dual Doppler radar analysis confirmed the presence of deep and strong (> 15 m s−1) updrafts in the parent cloud of one of the anvils. These features contrast with previous anvil measurements in tropical/maritime anvils that evidently do not exhibit the same frequency of frozen drop aggregates.
Improved light and temperature responses for light-use-efficiency-based GPP models
Authors: McCallum I. , Franklin O. , Moltchanova E. , Merbold L. , Schmullius C. , Shvidenko A. , Schepaschenko D. , Fritz S.
Published: October 2013

Abstract. Gross primary production (GPP) is the process by which carbon enters ecosystems. Models based on the theory of light use efficiency (LUE) have emerged as an efficient method to estimate ecosystem GPP. However, problems have been noted when applying global parameterizations to biome-level applications. In particular, model–data comparisons of GPP have shown that models (including LUE models) have difficulty matching estimated GPP. This is significant as errors in simulated GPP may propagate through models (e.g. Earth system models). Clearly, unique biome-level characteristics must be accounted for if model accuracy is to be improved. We hypothesize that in boreal regions (which are strongly temperature controlled), accounting for temperature acclimation and non-linear light response of daily GPP will improve model performance. To test this hypothesis, we have chosen four diagnostic models for comparison, namely an LUE model (linear in its light response) both with and without temperature acclimation and an LUE model and a big leaf model both with temperature acclimation and non-linear in their light response. All models include environmental modifiers for temperature and vapour pressure deficit (VPD). Initially, all models were calibrated against five eddy covariance (EC) sites within Russia for the years 2002–2005, for a total of 17 site years. Model evaluation was performed via 10-out cross-validation. Cross-validation clearly demonstrates the improvement in model performance that temperature acclimation makes in modelling GPP at strongly temperature-controlled sites in Russia. These results would indicate that inclusion of temperature acclimation in models on sites experiencing cold temperatures is imperative. Additionally, the inclusion of a non-linear light response function is shown to further improve performance, particularly in less temperature-controlled sites.
Sub-grid scale representation of vegetation in global land surface schemes: implications for estimation of the terrestrial carbon sink
Authors: Melton J. R. , Arora V. K.
Published: October 2013

Abstract. Terrestrial ecosystem models commonly represent vegetation in terms of plant functional types (PFTs) and use their vegetation attributes in calculations of the energy and water balance and to investigate the terrestrial carbon cycle. To accomplish these tasks, two approaches for PFT spatial representation are widely used: "composite" and "mosaic". The impact of these two approaches on the global carbon balance has been investigated with the Canadian Terrestrial Ecosystem Model (CTEM v 1.2) coupled to the Canadian Land Surface Scheme (CLASS v 3.6). In the composite (single-tile) approach, the vegetation attributes of different PFTs present in a grid cell are aggregated and used in calculations to determine the resulting physical environmental conditions (soil moisture, soil temperature, etc.) that are common to all PFTs. In the mosaic (multi-tile) approach, energy and water balance calculations are performed separately for each PFT tile and each tile's physical land surface environmental conditions evolve independently. Pre-industrial equilibrium CLASS-CTEM simulations yield global totals of vegetation biomass, net primary productivity, and soil carbon that compare reasonably well with observation-based estimates and differ by less than 5% between the mosaic and composite configurations. However, on a regional scale the two approaches can differ by > 30%, especially in areas with high heterogeneity in land cover. Simulations over the historical period (1959–2005) show different responses to evolving climate and carbon dioxide concentrations from the two approaches. The cumulative global terrestrial carbon sink estimated over the 1959–2005 period (excluding land use change (LUC) effects) differs by around 5% between the two approaches (96.3 and 101.3 Pg, for the mosaic and composite approaches, respectively) and compares well with the observation-based estimate of 82.2 ± 35 Pg C over the same period. Inclusion of LUC causes the estimates of the terrestrial C sink to differ by 15.2 Pg C (16%) with values of 95.1 and 79.9 Pg C for the mosaic and composite approaches, respectively. Spatial differences in simulated vegetation and soil carbon and the manner in which terrestrial carbon balance evolves in response to LUC, in the two approaches, yields a substantially different estimate of the global land carbon sink. These results demonstrate that the spatial representation of vegetation has an important impact on the model response to changing climate, atmospheric CO2 concentrations, and land cover.
Environmental and climatic changes in Central Chilean Patagonia since the Late Glacial (Mallín El Embudo, 44° S)
Authors: de Porras M. E. , Maldonado A. , Quintana F. A. , Martel-Cea A. , Reyes O. , Méndez C.
Published: October 2013

Abstract. Multi-millennial environmental and climatic changes in Central Chilean Patagonia (44–49° S) during the Last Glacial–Interglacial cycle have been of particular interest as changes in the position and strength of the Southern Westerlies are the major forcing factor conditioning the environmental dynamics. Recent attempts to reconstruct regional environmental and climatic signals from Central Chilean Patagonia reveal some discrepancies and unclear issues among the records. This paper presents the 13 ka pollen and charcoal records from Mallín El Embudo (44°40' S; 71°42' W) located in the deciduous Nothofagus forest in the middle Río Cisnes valley. The paper aims to (1) establish the timing and magnitude of local vegetation changes and fire activity since the Late Glacial and (2) integrate these results at the regional scale in order to discuss the discrepancies and depict the Central Chilean Patagonia environmental and climatic dynamics since Late Glacial. Open landscapes dominated by grasses associated with scattered Nothofagus forest patches dominated middle Río Cisnes valley between 13–11.2 ka suggesting low effective moisture but also reflecting that landscape configuration after glacial retreat was still ongoing. At 11.2 ka, a sudden development of an open and quite dynamic Nothofagus forest probably associated to the synchronous high fire activity occurred suggesting a rise in effective moisture. Since 9.5 ka, the record reflects the presence of a closed Nothofagus forest related to higher/similar effective moisture conditions than before but under an unmarked precipitation seasonality. The forest experienced a slight canopy opening since 5.7 ka, probably due to slightly drier conditions than before followed by a sudden change around 4.2 ka associated with fire and volcanic disturbances. The recovery of an open Nothofagus forest related to slight wetter conditions (similar to present) occurred around 2 ka and persisted under highly variable climatic conditions up to 0.1 ka when massive forest burning and logging due to European settlements occurred. Central Chilean Patagonian climatic and environmental changes at millennial-centennial time scales since Late Glacial were driven by changes in the Southern Westerlies latitudinal shift and/or intensity but during the Late Holocene fire, volcanism and humans arise as major forcings contributing to environmental dynamics.
Multiple knickpoints in an alluvial river generated by a single instantaneous drop in base level: experimental investigation
Authors: Cantelli A. , Muto T.
Published: October 2013

Abstract. Knickpoints often form in bedrock rivers in response to base level lowering. These knickpoints can migrate upstream without dissipating. In the case of alluvial rivers, an impulsive lowering of base level due to, for example, a fault associated with an earthquake or dam removal commonly produces smooth, upstream-progressing degradation. The knickpoint associated with suddenly lowered base level quickly dissipates. Here, however, we use experiments to demonstrate that, under conditions of Froude-supercritical flow over an alluvial bed, suddenly lowered base level can lead to the formation of upstream-migrating knickpoints that do not dissipate. The base level fall can generate a single knickpoint or multiple knickpoints. Multiple knickpoints take the form of cyclic steps (i.e., trains of upstream-migrating bedforms, each bounded by a hydraulic jump upstream and downstream). In our experiments, trains of knickpoints were transient, eventually migrating out of the alluvial reach as the bed evolved to a new equilibrium state regulated with lowered base level. Thus the allogenic perturbation of lowered base level can trigger the autogenic generation of multiple knickpoints, which are sustained until the alluvial reach recovers a graded state.
Voxel tree modeling for estimating leaf area density and woody material volume using 3-D LIDAR data
Authors: Hosoi F. , Nakai Y. , Omasa K.
Published: October 2013

Abstract. In this work, the main focus is on voxel tree modeling using 3-D lidar data for accurate leaf area density (LAD) and woody material volume estimation. For more accurate LAD estimation, the voxel model was constructed by combining airborne and portable ground-based lidar data. The profiles obtained by the two types of lidar complemented each other, thus eliminating blind regions and yielding more accurate LAD profiles than could be obtained by using each type of lidar alone. Parts of the LAD profiles that were underestimated even when data from both lidars were combined were interpolated by using a Gaussian function, yielding improved results. A laser beam coverage index, Ω, incorporating the lidar's laser beam settings and a laser beam attenuation factor, was proposed. This index showed general applicability to explain the LAD estimation error for LAD measurements using different types of lidars. In addition, we proposed a method for accurate woody material volume estimation based on a 3-D voxel-based solid modeling of the tree from portable scanning lidar data. The solid model was composed of consecutive voxels that filled the outer surface and the interior of the stem and large branches. By using the model, the woody material volume of not only the whole target tree but also of any part of the target tree can be directly calculated easily and accurately by counting the number of corresponding voxels and multiplying the result by the per-voxel volume.
Radiometric Correction of Terrestrial LiDAR Data for Mapping of Harvest Residues Density
Authors: Koenig K. , Höfle B. , Müller L. , Hämmerle M. , Jarmer T. , Siegmann B. , Lilienthal H.
Published: October 2013

Abstract. In precision agriculture detailed geoinformation on plant and soil properties plays an important role. Laser scanning already has been used to describe in-field variations of plant growth in 3D and over time and can serve as valuable complementary topographic data set for remote sensing, such as deriving soil properties from hyperspectral sensors. In this study full-waveform laser scanning data acquired with a Riegl VZ-400 instrument is used to classify 3D point clouds into post-harvest straw residues and bare soil. A workflow for point cloud based classification is presented using radiometric and geometric point features. A radiometric correction is performed by using a range-correction function f(r), which is derived from lab experiments with a reference target of known reflectance. Thereafter, the corrected signal amplitude and local height features are explored with respect to the target classes. The following procedure includes feature calculation, decision tree analysis, point cloud classification and finally result validation using detailed classified reference RGB images. The classification tree separates the classes of harvest residues and bare soil with an accuracy of 96% by using geometric and radiometric features. The LiDAR-derived harvest residue coverage value of 75% lies in accordance with the image-based reference (coverage of 68%). The results indicate the high potential of radiometric features for natural surface classification, particularly in combination with geometric features.
Optimizing detection of road furniture (pole-like object) in Mobile Laser Scanner data
Authors: Li D. , Oude Elberink S.
Published: October 2013

Abstract. Due to the road safety problem is becoming more and more serious recent years, existing road safety assessment by using automatic method is necessary. Meanwhile, since the pole-like objects have large effect on road safety and are in high demand as facilities to be managed, the automatic pole-like objects extraction is becoming a hot issue. As a result, a robust, quick and automatic pole-like object detection algorithm in MLS data is proposed in this paper. Two datasets are tested to show performance of the proposed algorithm, it demonstrates that it is feasible to detect tree with an overall accuracy of over 92% and other pole-like object of 72% in dataset A and 82% of tree points and 75% of other pole points in dataset B.
Registration of terrestrial mobile laser data on 2D or 3D geographic database by use of a non-rigid ICP approach.
Authors: Monnier F. , Vallet B. , Paparoditis N. , Papelard J.-P. , David N.
Published: October 2013

Abstract. This article presents a generic and efficient method to register terrestrial mobile data with imperfect location on a geographic database with better overall accuracy but less details. The registration method proposed in this paper is based on a semi-rigid point to plane ICP ("Iterative Closest Point"). The main applications of such registration is to improve existing geographic databases, particularly in terms of accuracy, level of detail and diversity of represented objects. Other applications include fine geometric modelling and fine façade texturing, object extraction such as trees, poles, road signs marks, facilities, vehicles, etc. The geopositionning system of mobile mapping systems is affected by GPS masks that are only partially corrected by an Inertial Navigation System (INS) which can cause an important drift. As this drift varies non-linearly, but slowly in time, it will be modelled by a translation defined as a piecewise linear function of time which variation over time will be minimized (rigidity term). For each iteration of the ICP, the drift is estimated in order to minimise the distance between laser points and planar model primitives (data attachment term). The method has been tested on real data (a scan of the city of Paris of 3.6 million laser points registered on a 3D model of approximately 71,400 triangles).
Comparison of discrete and full-waveform ALS for dead wood detection
Authors: Mücke W. , Hollaus M. , Pfeifer N. , Schroiff A. , Deák B.
Published: October 2013

Abstract. The amount of dead wood is a significant parameter for the description and assessment of forest habitat quality under the terms of the Habitats directive and Natura 2000 guidelines. EU member states are obliged by the Natura 2000 regulations to report on habitat quality in a regular interval of six years. To fulfil this task, the areas should be surveyed in the field, which requires an enormous amount of workload if done only by conventional field work. In this study the applicability of airborne laser scanning data as the single data source for the detection of downed trees in forest habitats is investigated. A focus is laid on the comparison of point clouds with only discrete (XYZ) and full-waveform (including echo width) information as input data. In our paper we present an automatic workflow which is able to detect downed trees with high completeness for both data sets (77.8% for discrete and 75.6% for full-waveform data). Due to large amount of false positives, the correctness using discrete ALS data is poorer (63.1%) than for full-waveform data (89.9%). It was found that the quality of the result is also influenced by factors such as dimension, state of decay, vegetation density and penetration of the foliage by the laser.
Automatic registration of optical imagery with 3d lidar data using local combined mutual information
Authors: Parmehr E. G. , Fraser C. S. , Zhang C. , Leach J.
Published: October 2013

Abstract. Automatic registration of multi-sensor data is a basic step in data fusion for photogrammetric and remote sensing applications. The effectiveness of intensity-based methods such as Mutual Information (MI) for automated registration of multi-sensor image has been previously reported for medical and remote sensing applications. In this paper, a new multivariable MI approach that exploits complementary information of inherently registered LiDAR DSM and intensity data to improve the robustness of registering optical imagery and LiDAR point cloud, is presented. LiDAR DSM and intensity information has been utilised in measuring the similarity of LiDAR and optical imagery via the Combined MI. An effective histogramming technique is adopted to facilitate estimation of a 3D probability density function (pdf). In addition, a local similarity measure is introduced to decrease the complexity of optimisation at higher dimensions and computation cost. Therefore, the reliability of registration is improved due to the use of redundant observations of similarity. The performance of the proposed method for registration of satellite and aerial images with LiDAR data in urban and rural areas is experimentally evaluated and the results obtained are discussed.
Total Least Squares Registration of 3D Surfaces
Authors: Aydar U. , Akca D. , Altan M. O. , Akyilmaz O.
Published: October 2013

Abstract. Co-registration of point clouds of partially scanned objects is the first step of the 3D modeling workflow. The aim of coregistration is to merge the overlapping point clouds by estimating the spatial transformation parameters. In computer vision and photogrammetry domain one of the most popular methods is the ICP (Iterative Closest Point) algorithm and its variants. There exist the 3D Least Squares (LS) matching methods as well (Gruen and Akca, 2005). The co-registration methods commonly use the least squares (LS) estimation method in which the unknown transformation parameters of the (floating) search surface is functionally related to the observation of the (fixed) template surface. Here, the stochastic properties of the search surfaces are usually omitted. This omission is expected to be minor and does not disturb the solution vector significantly. However, the a posteriori covariance matrix will be affected by the neglected uncertainty of the function values of the search surface. . This causes deterioration in the realistic precision estimates. In order to overcome this limitation, we propose a method where the stochastic properties of both the observations and the parameters are considered under an errors-in-variables (EIV) model. The experiments have been carried out using diverse laser scanning data sets and the results of EIV with the ICP and the conventional LS matching methods have been compared.
Non-linear methods for inferring lidar metrics using SPOT-5 textural data
Authors: Shamsoddini A. , Trinder J. C. , Turner R.
Published: October 2013

Abstract. Although many studies have demonstrated the utility of airborne lidar for forest inventory, the acquisition and processing of the data can be cost prohibitive for small areas. In such cases, it may be possible to emulate lidar metrics using more affordable optical data. This study explored processing methods for predicting lidar metrics using SPOT-5 textural data. Multiple-linear regression (MLR) was compared with non-linear machine learning techniques including multi-layer perceptron (MLP) artificial neural networks (ANN), rational basis function (RBF) ANN and regression tree (RT). For this purpose, 11 grey level co-occurrence matrix (GLCM) indices were calculated for bands, band ratios and principal components (PCs) of SPOT-5 multispectral image. SPOT-5 metrics were correlated with 25 lidar metrics collected over a Pinus radiata plantation. After dimensionality reduction, random forest feature selection was applied to select the most relevant SPOT-5 textural attributes for inferring each lidar metric. The results showed that the non-linear methods including MLP and RBF methods are more promising for modelling lidar metrics using SPOT-5 data than MLR and RT.
Change Detection in 3D Point Clouds Acquired by a Mobile Mapping System
Authors: Xiao W. , Vallet B. , Paparoditis N.
Published: October 2013

Abstract. Thanks to the development of Mobile mapping systems (MMS), street object recognition, classification, modelling and related studies have become hot topics recently. There has been increasing interest in detecting changes between mobile laser scanning (MLS) point clouds in complex urban areas. A method based on the consistency between the occupancies of space computed from different datasets is proposed. First occupancy of scan rays (empty, occupied, unknown) are defined while considering the accuracy of measurement and registration. Then the occupancy of scan rays are fused using the Weighted Dempster–Shafer theory (WDST). Finally, the consistency between different datasets is obtained by comparing the occupancy at points from one dataset with the fused occupancy of neighbouring rays from the other dataset. Change detection results are compared with a conventional point to triangle (PTT) distance method. Changes at point level are detected fully automatically. The proposed approach allows to detect changes at large scales in urban scenes with fine detail and more importantly, distinguish real changes from occlusions.
Rigorous LiDAR Strip Adjustment with Triangulated Aerial Imagery
Authors: Zhang Y. J. , Xiong X. D. , Hu X. Y.
Published: October 2013

Abstract. This paper proposes a POS aided LiDAR strip adjustment method. Firstly, aero-triangulation of the simultaneously obtained aerial images is conducted with a few photogrammetry-specific ground control points. Secondly, LiDAR intensity images are generated from the reflectance signals of laser foot points, and conjugate points are automatically matched between the LiDAR intensity image and the aero-triangulated aerial image. Control points used in LiDAR strip adjustment are derived from these conjugate points. Finally, LiDAR strip adjustment of real data is conducted with the POS aided LiDAR strip adjustment method proposed in this paper, and comparison experiment using three-dimensional similarity transformation method is also performed. The results indicate that the POS aided LiDAR strip adjustment method can significantly correct the planimetric and vertical errors of LiDAR strips. The planimetric correction accuracy is higher than average point distance while the vertical correction accuracy is comparable to that of the result of aero-triangulation. Moreover, the proposed method is obliviously superior to the traditional three-dimensional similarity transformation method.
Range image segmentation for tree detection in forest scans
Authors: Bienert A. , Schneider D.
Published: October 2013

Abstract. To make a tree-wise analysis inside a forest stand, the trees have to be identified. An interactive segmentation is often labourintensive and time-consuming. Therefore, an automatic detection process will aspired using a range image. This paper presents a method for the segmentation of range images extracted from terrestrial laser scanner point clouds of forest stands. After range image generation the segmentation is carried out with a connectivity analysis using the differences of the range values as homogeneity criterion. Subsequently, the tree detection is performed interactively by analysing one horizontal image line. When passing objects with a specific width, the object indicates a potential tree. By using the edge points of a segmented pixel group the tree position and diameter is calculated. Results from one test site are presented to show the performance of the method.
Development of a stereo-laser-profile-system for the optical inspection of welding seams
Authors: Ekkel T. , Meyer A. M. , Luhmann T. , Hastedt H. , Bethmann F.
Published: October 2013

Abstract. This research project focuses on the development of an optical 3D measuring system that enables high accurate surface measurements of welding seams in order to detect impurities. The systems concept is based on a stereo camera system in conjunction with a projecting line laser. A second camera system is used as tracking or positioning component to obtain the position of the measuring systems in object space. The complete stereo laser-profile system will be used as a hand-held system. The development, optimization and testing of the system components (stereo camera system with projecting laser line and tracking component) for surface measurements as well as calibration and accuracy evaluations are the main objectives within this research project. Testing procedures and probes are constructed and evaluated to verify the results. The development considers conditions for a future adaption to underwater use.
Daily Price Cycles and Constant Margins: Recent Events in Canadian Gasoline Retailing
Authors: Atkinson Benjamin , Eckert Andrew , West Douglas S.
Published: October 2013

Retail gasoline pricing in Canada has typically followed certain distinct patterns, ranging from long durations of price rigidity relative to wholesale prices to daily price cycles. This paper examines recent changes to pricing patterns in Canadian cities resulting in new equilibrium behavior, and discusses possible reasons for these changes. Using high frequency retail price data obtained from GasBuddy.com, it is demonstrated that volatility changes exhibited in Toronto appear to correspond to an increased frequency of the price cycle, and replacement of the cycle with fixed retail margins. While multiple factors may have contributed to the first pricing change, the second change corresponds closely to a refinery fire in southern Ontario; this temporary event (in conjunction with a rail strike and refinery maintenance) could have triggered a permanent change in equilibrium behavior. This paper also illustrates problems for academic researchers and policymakers when using low frequency price data to analyze pricing in a market characterized by a price cycle.
The Impact of Imperfect Competition in Emission Permits Trading on Oligopolistic Electricity Markets
Authors: Limpaitoon Tanachai , Chen Yihsu , Oren Shmuel S.
Published: October 2013

The impact and efficacy of a cap-and-trade regulation on the electric power industry depend on interactions of demand elasticity, transmission network, market structure, and strategic behavior of generation firms. This paper develops an equilibrium model of an oligopoly electricity market in conjunction with a Cap-and-Trade emissions permits market to study such interactions. The concept of conjectural variations is proposed to account for imperfect competition in the permits market. We demonstrate the model using a WECC 225-bus system with a detailed representation of the California market. In particular, we examine the extent to which permit trading strategies affect the market outcome. We find that a firm with more efficient technologies can employ strategic withholding of permits, which allows for its increase in output share in the electricity market at the expense of other less efficient firms.
Quality and safety of camel milk along the value chain in Eastern Ethiopia
Authors: Adugna Mulugojjam , Seifu Eyassu , Kebeded Ameha , Doluschitz Reiner
Published: October 2013

The safety of camel milk was assessed along the value chain in Erer, eastern Ethiopia. A total of 24 camel milk samples were aseptically collected from producers in Erer (n=12), and wholesalers and retailers (n=12) along the chain. Milk quality parameters were analyzed following standard procedures. The mean (±SD) total bacteria (TBC), Enterobacteriaceae (EC), coliform (CC), spore-forming bacteria (SFBC) and yeast and mould (YMC) counts of the milk samples analyzed were 5.2 ± 1.90, 3.2 ± 2.30, 2.9 ± 2.27, 2.1 ± 2.41 and 2.7 ± 1.61 log10 cfu mL-1, respectively. The TBC, EC, CC and SFBC of milk samples obtained from retailers in the final marketing sites were significantly higher (P < 0.05) than those obtained from producers and wholesalers in Erer. Salmonella spp. was detected in milk samples collected from all sites. Other microorganisms isolated from camel milk samples include Staphylococcus aureus (16.2%), Entrobacter spp. (14.9%), Streptococcus spp. (13.5%),Escherichia coli (8.1%), Acinetobacter spp. (7.4%), Staphylococcus epidermidis (6.8%), Klebsiella spp. (6.1%), Bacillus spp. (5.4%), Corynebacterium spp. (5.4%), Micrococcus spp. (4.7%), Lactobacillus spp. (4.1%), Listeria spp. (4.1%), Pseudomonas spp. (2%) and Shigella spp. (1.4% ). The quality of camel milk produced in the study area was generally poor and microbial contamination of camel milk occurs along the value chain while it is transported from the production site to the market. This calls for strict hygienic measures along the entire value chain in order to improve the quality and safety of camel milk produced in the area evaluated.
First 2 years of TanDEM‐X mission: Interferometric performance overview
Authors: Martone Michele , Rizzoli Paola , Bräutigam Benjamin , Krieger Gerhard
Published: October 2013

The TerraSAR‐X add‐on for Digital Elevation Measurement (TanDEM‐X) mission comprises two nearly identical satellites: TerraSAR‐X (TSX, launched in June 2007), and TanDEM‐X (TDX, launched in June 2010), which form an innovative and flexible single‐pass radar interferometer. The primary objective of the mission is to generate a worldwide and consistent digital elevation model (DEM) with an unprecedented accuracy. After a calibration phase of the TDX satellite, which was performed during the first 3 months after its launch, the two satellites were brought into close formation to begin the bistatic commissioning phase. Then, in December 2010, TanDEM‐X started the operational global DEM acquisition in bistatic configuration. During the last 2 years, dedicated analyses on test acquisitions as well as persistent monitoring of the interferometric performance have been carried out, which are the subject of this paper. Key quantities in estimating interferometric performance such as coherence, relative height error, and phase‐unwrapping indicators are investigated, showing the outstanding capabilities of TanDEM‐X. Then, the main focus is shifted to those critical areas which, for various reasons, have shown unsatisfactory data quality and therefore must be reacquired with optimized imaging geometries in order to fulfill the DEM accuracy requirements. Promising results have been obtained so far, and future strategies to handle the critical data are discussed. This paper will present an overview of the interferometric performance of TanDEM‐X, based on investigations performed in the first 2 years of mission operation, and will include results from the bistatic commissioning phase until the end of the first global DEM acquisition.
Sea level changes forced by Southern Ocean winds
Authors: Frankcombe Leela M. , Spence Paul , Hogg Andrew McC. , England Matthew H. , Griffies Stephen M.
Published: October 2013

On regional scales, changes in sea level are significantly affected by local dynamical changes. Westerly winds over the Southern Ocean have been strengthening and shifting southward in recent decades, and this change is projected to continue in the future. This study applies wind forcing anomalies to an eddy‐permitting ocean model to study the dynamical response to a Southern Hemisphere westerly wind increase and/or southward shift. It is shown that the applied wind anomalies result in a change in sea surface slope across the Antarctic Circumpolar Current such that a fall in sea level occurs around the Antarctic continental margin. The Antarctic Circumpolar Current transport and regional sea level are particularly sensitive to latitudinal shifts in the wind, with a much more muted response found when only wind strengthening is applied. In addition to the local sea level changes, Southern Ocean winds also have a global effect through changing ocean heat content and the global overturning circulation.
Long‐term modulations of Saturn's auroral radio emissions by the solar wind and seasonal variations controlled by the solar ultraviolet flux
Authors: Kimura T. , Lamy L. , Tao C. , Badman S. V. , Kasahara S. , Cecconi B. , Zarka P. , Morioka A. , Miyoshi Y. , Maruno D. , Kasaba Y. , Fujimoto M.
Published: October 2013

Saturn's auroral activities have been suggested to be controlled by the seasonal variations of the polar ionospheric conductivities and atmospheric conditions associated with the solar extreme ultraviolet (EUV) flux. However, they have not yet been explained self‐consistently by only the seasonal solar EUV effects. This study investigates the long‐term variations of Saturnian Kilometric Radiation (SKR) as a proxy of the auroral activities, which were observed by Cassini's Radio and Plasma Wave Science experiment mostly during the southern summer (DOY (day of year) 001 2004 to DOY 193 2010). We deduced the height distribution of the SKR source region in the Northern (winter) and Southern (summer) Hemispheres from the remote sensing of SKR spectra. The peak spectral density of the southern (summer) SKR was found to be up to 100 times greater than that of the northern (winter) SKR, and the altitude of the peak flux was similar (∼ 0.8 Rs) in the Northern and Southern Hemispheres. The spectral densities in both hemispheres became comparable with each other around equinox in August 2009. These results suggest a stronger SKR source region during the summer than the winter related to the seasonal EUV effect, which is opposite to the trend observed in the Earth's kilometric radiation. A long‐term correlation analysis was performed for the SKR, solar EUV flux, and solar wind parameters extrapolated from Earth's orbit by an magnetohydrodynamical simulation focusing on variations on timescales longer than several weeks. We confirmed clear positive correlations between the solar wind dynamic pressure and peak flux density in both the Southern and Northern Hemispheres during the declining phase of the solar cycle. We conclude that the solar wind variations on the timescale of the solar cycle control the SKR source region. In addition, it was also confirmed that the south‐to‐north ratios of SKR power flux and source altitudes are positively correlated with the solar EUV flux. This result strongly supports a seasonal EUV effect on the SKR source region. The variations of SKR activity over both seasonal and solar cycles are discussed in comparison to the terrestrial case.
Direct observation of the CRAND proton radiation belt source
Authors: Selesnick R. S. , Hudson M. K. , Kress B. T.
Published: October 2013

Observations of geomagnetically trapped 27–45 MeV protons following the November 2003 magnetic storm show a gradual intensity rise that is interpreted as a direct measurement of the cosmic ray albedo neutron decay (CRAND) source strength. The intensity rise is simulated by combining the detector response function with a model CRAND source, obtained by drift‐averaging neutron intensity from Monte Carlo simulation of cosmic ray interactions in the atmosphere. The simulation, for 2.4<L<2.7, matches the data within statistical uncertainties, verifying the CRAND model. Another simulation includes the effects of solar proton trapping and other known radiation belt processes. It further shows that the CRAND source was predominant, while radial diffusion and magnetic storm losses effected minor corrections in certain L ranges.
Stimulated Brillouin scatter and stimulated ion Bernstein scatter during electron gyroharmonic heating experiments
Authors: Fu H. , Scales W. A. , Bernhardt P. A. , Samimi A. , Mahmoudian A. , Briczinski S. J. , McCarrick M. J.
Published: October 2013

Results of secondary radiation, Stimulated Electromagnetic Emission (SEE), produced during ionospheric modification experiments using ground‐based high‐power radio waves are reported. These results obtained at the High Frequency Active Auroral Research Program (HAARP) facility specifically considered the generation of Magnetized Stimulated Brillouin Scatter (MSBS) and Stimulated Ion Bernstein Scatter (SIBS) lines in the SEE spectrum when the transmitter frequency is near harmonics of the electron gyrofrequency. The heater antenna beam angle effect was investigated on MSBS in detail and shows a new spectral line postulated to be generated near the upper hybrid resonance region due to ion acoustic wave interaction. Frequency sweeping experiments near the electron gyroharmonics show for the first time the transition from MSBS to SIBS lines as the heater pump frequency approaches the gyroharmonic. Significantly far from the gyroharmonic, MSBS lines dominate, while close to the gyroharmonic, SIBS lines strengthen while MSBS lines weaken. New possibilities for diagnostic information are discussed in light of these new observations.