bluuebunny/crossref_metadata_2025 huggingface dataset:
Confinement Shear Effect in Fiber Composites
Authors: Zhang Pu Zi , Liu Jin Xing
Published: June 2019

Composites have been playing an increasingly important role in various engineering applications. We examine the confinement shear effect arising in the neighborhood of the fiber-matrix interface in fiber-reinforced materials, which is a problem calling for further investigations. It is well known that the progressive failure process strongly depends on the interfacial transition zone (ITZ). Thus, we take the studied material as three-phased, i.e. fiber, matrix and interface in between. The generalized beam (GB) lattice model is adopted to simulate the compressive failure behavior of a representative volume element with one fiber included. Numerical results are provided to explain the confinement shear effect during the progressive failure process in specimens with various fiber-matrix properties, fiber orientations and distributions.
Stresses Analysis of Hypocycloidal Gear Transmissions
Authors: Tan Chung Ming , Chang Mau Yiu
Published: June 2019

The objective of this research is to enhance the performance of a Hypocycloidal Gear Transmission (HGT) by selecting the favorable gear profile which has the most significant effects on performance. The research presents computer-aided design and analysis of the HGT. Careful design of the curtate-cycloid tooth profile can further enhance the performance of the HGT by dramatically improving the Hertz contact property. This high contact ratio leads to ideal load distribution. In the loaded tooth contact analysis, the real contact ratio under the tooth deformation was analyzed for demonstration of an effective self-protecting feature, which makes the HGT suitable for extremely heavy load applications. This paper successfully proves that the HGT is a promising architecture for the high reduction ratio reducers. The design and analysis of these prototype HGTs have been fully addressed here.
Computer Modeling and Analysis of the Energy-Power Process Parameters of the Combined Machining of Alloys Al-Mg System
Authors: Sidelnikov Sergey , Samchuk Anton , Voroshilov D. , Gorbunov Yuriy , Ber Vladimir , Galiev Roman , Sokolov Ruslan , Bespalov Vadim
Published: June 2019

Article shows the results of studies of the process of combined rolling-extruding of an alloy of the Al-Mg system (AlMg6) under various temperature-speed and deformation conditions. Calculations shows that with increasing metal temperature at the entrance to the deformation center, the values ​​of the forces on the rolls and the die decrease, the increase in drawing leads to an increase in the values ​​of forces on both the rolls and the die, and an increase in the deformation rate leads to hardening of the metal and increasing energy parameters of the process of combined machining. However, the maximum extruding force on the combined machining units is 5-10 times lower than the efforts to obtain the same press products on hydraulic presses. A computer model of the combined machining process created with the help of the DEFORM 3D complex, the analysis of the metal flow is made, the temperature distribution of the metal over the section of the workpiece invstigated when producing round bars of different diameters. Shaping of the metal corresponds to the data of experimental and theoretical studies, while the deformation center has a characteristic appearance, including the gripping zones of the workpiece and its rolling, repressing and extrusion. The peculiarity for this alloy is that with a drawing ratio of μ = 3.7 and a strain rate of ξ = 0.78 s-1, the steady extruding process takes place without completely filling the deformation zone from the side of the roll with a protrusion. An increase in drawing ratio or strain rate leads to a decrease in the contactless zone or to its absence. The change in metal temperature also depends on the presence of a contactless zone, which contributes to an increase in heat transfer from the billet to the rolls. The results of the research were used to develop the technology for the production of welding wire from Al-Mg system alloys.
An Analysis of Air Permeability of Cotton-Fibre-Based Socks
Authors: Wang Wen Yi , Hui Kwok Tung , Kan Chi Wai , Maha-In Kongkiat , Pukjaroon Salakchit , Wanitchottayanont Siriorn , Mongkholrattanasit Rattanaphol
Published: June 2019

Socks are the clothing preserving the foot in thermal neutrality and preventing foot from blister generating. The development of socks has been diversified like the type, materials, and function, etc. Socks with good quality are conducive to prevent foot disease or smelly odor from foot. The wearing comfort of socks can be affected by the fabric properties of air permeability. The present study aims to investigate the relationship between the fabric parameters and air permeability of knitted socks fabric. The ventilation of socks fabric was measured by the KES-F8 automatic air permeability tester. It was found that the air permeability of fabric was negatively proportional to the content of cotton, yarn count and thickness, before washing. Meanwhile, washing was found to increase the air permeability.
Mechanical and Rheological Properties of High Density Polyethylene Reinforced Polyvinyl Alcohol Fiber Composites
Authors: Chafidz Achmad , Faisal R.M. , Fardhyanti Dewi Selvia , Kustiningsih Indar , Suhartono Jono
Published: June 2019

In the current study, high density polyethylene filled polyvinyl alcohol fiber composites have been made via melt compounding process using a twin screw extruder. Four different fiber loadings (0, 5, 10, 20 wt%) together with HDPE matrix were mixed and melt blended with the extruder. The prepared composites were tested for their melt rheological properties, mechanical properties, FT-IR spectra, and water absorption behavior. Rheological test results exhibited that complex viscosity of the composites were higher than the neat HDPE and increased with the increase of PVA loadings. Moreover, the improvement of complex viscosity was more prominent at higher PVA loadings (i.e. PVAC-10 and PVAC-20) than at the lower one (PVAC-5). The flexural modulus and strength were higher for the all composites samples when compared to the neat HDPE, indicating that the incorporation of PVA fiber has successfully improved the mechanical (i.e. flexural) properties of the HDPE/PVA fiber composites. The FTIR analysis results prevailed the appearance of C=O spectrum at 2361 cm-1 that corresponding to carbonyl bond of PVA fiber on the whole composites. Additionally, from the water uptake test, the degree of water absorption of the composites increased with the fiber loadings.
Risk Factors for Lateral Ankle Sprains and Chronic Ankle Instability
Authors: Delahunt Eamonn , Remus Alexandria
Published: June 2019

Lateral ankle sprains (LASs) are a common injury sustained by individuals who participate in recreational physical activities and sports. After an LAS, a large proportion of individuals develop long-term symptoms, which contribute to the development of chronic ankle instability (CAI). Due to the prevalence of LASs and the propensity to develop CAI, collective efforts toward reducing the risk of sustaining these injuries should be a priority of the sports medicine and sports physiotherapy communities. The comprehensive injury-causation model was developed to illustrate the interaction of internal and external risk factors in the occurrence of the inciting injury. The ability to mitigate injury risk is contingent on a comprehensive understanding of risk factors for injury. The objective of this current concepts review is to use the comprehensive injury-causation model as a framework to illustrate the risk factors for LAS and CAI based on the literature.
Alterations in Cortical Activation Among Individuals With Chronic Ankle Instability During Single-Limb Postural Control
Authors: Rosen Adam B. , Yentes Jennifer M. , McGrath Melanie L. , Maerlender Arthur C. , Myers Sara A. , Mukherjee Mukul
Published: June 2019

Context

Chronic ankle instability (CAI) is characterized by repetitive ankle sprains and perceived instability. Whereas the underlying cause of CAI is disputed, alterations in cortical motor functioning may contribute to the perceived dysfunction.

Objective

To assess differences in cortical activity during single-limb stance among control, coper, and CAI groups.

Design

Cross-sectional study.

Setting

Biomechanics laboratory.

Patients or Other Participants

A total of 31 individuals (10 men, 21 women; age = 22.3 ± 2.4 years, height = 169.6 ± 9.7 cm, mass = 70.6 ± 11.6 kg), who were classified into control (n = 13), coper (n = 7), and CAI (n = 11) groups participated in this study.

Intervention(s)

Participants performed single-limb stance on a force platform for 60 seconds while wearing a 24-channel functional near-infrared spectroscopy system. Oxyhemoglobin (HbO2) changes in the supplementary motor area (SMA), precentral gyrus, postcentral gyrus, and superior parietal lobe were measured.

Main Outcome Measure(s)

Differences in averages and standard deviations of HbO2 were assessed across groups. In the CAI group, correlations were analyzed between measures of cortical activation and Cumberland Ankle Instability Tool (CAIT) scores.

Results

No differences in average HbO2 were present for any cortical areas. We observed differences in the standard deviation for the SMA across groups; specifically, the CAI group demonstrated greater variability than the control (r = 0.395, P = .02; 95% confidence interval = 0.34, 0.67) and coper (r = 0.38, P = .04; 95% confidence interval = −0.05, 0.69) groups. We demonstrated a strong correlation that was significant in the CAI group between the CAIT score and the average HbO2 of the precentral gyrus (ρ = 0.64, P = .02) and a strong correlation that was not significant between the CAIT score and the average HbO2 of the SMA (ρ = 0.52, P = .06).

Conclusions

The CAI group displayed large differences in SMA cortical-activation variability. Greater variations in cortical activation may be necessary for similar static postural-control outcomes among individuals with CAI. Consequently, variations in cortical activation for these areas provide evidence for an altered neural mechanism of postural control among populations with CAI.
Altered Walking Neuromechanics in Patients With Chronic Ankle Instability
Authors: Son S. Jun , Kim Hyunsoo , Seeley Matthew K. , Hopkins J. Ty
Published: June 2019

Context

The literature on gait kinematics and muscle activation in chronic ankle instability (CAI) is limited. A comprehensive evaluation of all relevant gait measures is needed to examine alterations in gait neuromechanics that may contribute to recurrent sprain.

Objective

To compare walking neuromechanics, including kinematics, muscle activity, and kinetics (ie, ground reaction force [GRF], moment, and power), between participants with and those without CAI by applying a novel statistical analysis to data from a large sample.

Design

Controlled laboratory study.

Setting

Biomechanics laboratory.

Patients or Other Participants

A total of 100 participants with CAI (49 men, 51 women; age = 22.2 ± 2.3 years, height = 174.0 ± 9.7 cm, mass = 70.8 ± 14.4 kg) and 100 individuals without CAI serving as controls (55 men, 45 women; age = 22.5 ± 3.3 years, height = 173.1 ± 13.3 cm, mass = 72.6 ± 18.7 kg).

Intervention(s)

Participants performed 5 trials of walking (shod) at a self-selected speed over 2 in-ground force plates.

Main Outcome Measure(s)

Three-dimensional GRFs, lower extremity joint angles, internal joint moments, joint powers, and activation amplitudes of 6 muscles were recorded during stance.

Results

Compared with the control group, the CAI group demonstrated (1) increased plantar flexion or decreased dorsiflexion, increased inversion or decreased eversion, decreased knee flexion, decreased knee abduction, and increased hip-flexion angles; (2) increased or decreased inversion, increased plantar flexion, decreased knee extension, decreased knee abduction, and increased hip-extension moments; (3) increased vertical, braking, and propulsive GRFs; (4) increased hip eccentric and concentric power; and (5) altered muscle activation in all 6 lower extremity muscles.

Conclusions

The CAI group demonstrated a hip-dominant strategy by limiting propulsive forces at the ankle while increasing force generation at the hip. The different walking neuromechanics exhibited by the CAI group could represent maladaptive strategies that developed after the initial sprain or an injurious gait pattern that may have predisposed the participants to their initial injuries. Increased joint loading and altered kinematics at the foot and ankle complex during initial stance could affect the long-term health of the ankle articular cartilage.
Case Report: Spontaneous Resolution of Intracavitary Hepatic Artery Pseudoaneurysm Caused by Amebic Liver Abscess following Percutaneous Drainage
Authors: Priyadarshi Rajeev Nayan , Kumar Ramesh , Anand Utpal
Published: June 2019

Intrahepatic pseudoaneurysm (IHPA) is generally iatrogenic, and it warrants urgent management because of its reportedly significant risk of rupture leading to considerable mortality. Intrahepatic pseudoaneurysm caused by amebic liver abscess (ALA) is exceedingly rare with fewer than seven published reports. All reported symptomatic cases have been treated with hepatic artery embolization; therefore, little is known about its natural course and effect of abscess drainage on its outcome. We report the first case of symptomatic intracavitary IHPA caused by ALA in which ultrasound-guided percutaneous catheter drainage of the abscess resulted in the spontaneous resolution of the IHPA.
Case Report: Cardiac Tamponade in Dengue Hemorrhagic Fever: An Unusual Manifestation of a Common Disease
Authors: Biswas Sagnik , Kumar Prabhat , Tansir Ghazal , Biswas Ashutosh
Published: June 2019

Dengue hemorrhagic fever is one of the most commonly encountered mosquito-borne viral infections of humans worldwide with multiple reported outbreaks. Cardiac involvement is a known manifestation of the disease usually presenting as rhythm abnormalities, myocarditis, or pericardial effusion, which may be clinically asymptomatic. We describe a case of a 30-year-old woman who presented to us with high-grade fever, headache, retro-orbital pain, generalized maculopapular rash with bilateral pleural effusion, and hypotension. Dengue non-structural protein 1 (NS1) antigen and IgM antibodies were positive on admission, supporting a diagnosis of dengue hemorrhagic fever. Cardiac troponin-I was elevated on admission (65 ng/L) with diffuse convex ST segment elevations on electrocardiogram, suggestive of possible myopericarditis. Echocardiogram on admission revealed minimal pericardial effusion with preserved ejection fraction. Despite administration of fluids and inotrope use, the patient’s hypotension progressively deteriorated over the next 6 hours, associated with decreased urine output and worsening sensorium. Clinical examination revealed muffled heart sounds and raised jugular venous pressure. A repeat echocardiogram confirmed an increase in the pericardial effusion manifesting as cardiac tamponade. Ultrasound-guided pigtail catheter insertion led to a prompt removal of the excessive pericardial fluid and correction of hypotension. Early identification of this uncommon but important complication of dengue hemorrhagic fever led to a good outcome in our case.
Comparison of the GRUAN data products for Meisei RS-11G and Vaisala RS92-SGP radiosondes at Tateno (36.06° N, 140.13° E), Japan
Authors: Kobayashi Eriko , Hoshino Shunsuke , Iwabuchi Masami , Sugidachi Takuji , Shimizu Kensaku , Fujiwara Masatomo
Published: June 2019

Abstract. A total of 87 dual flights of Meisei RS-11G radiosondes
and Vaisala RS92-SGP radiosondes were carried out at the Aerological
Observatory of the Japan Meteorological Agency (36.06∘ N,
140.13∘ E, 25.2 m) from April 2015 to June 2017. Global
Climate Observing System (GCOS) Reference Upper-Air Network (GRUAN) data
products from both sets of radiosonde data for 52 flights were subsequently
created using a documented processing program along with the provision of
optimal estimates for measurement uncertainty. Differences in the
performance of the radiosondes were then quantified using the GRUAN data
products. The temperature measurements of RS-11G were, on average,
0.4 K
lower than those of RS92-SGP in the stratosphere for daytime observations.
The relative humidity measurements of RS-11G were, on average, 2 % RH (relative humidity) lower
than those of RS92-SGP under 90 % RH–100 % RH conditions, while RS-11G gave on
average 5 % RH higher values than RS92-SGP under ≤50 % RH
conditions. The results from a dual flight of RS-11G and a cryogenic
frost point hygrometer (CFH) also showed that RS-11G gave 1 % RH–10 % RH higher
values than the CFH in the troposphere. Differences between the RS-11G and
RS92-SGP temperature and relative humidity measurements, based on combined
uncertainties, were also investigated to clarify major influences behind the
differences. It was found that temperature differences in the stratosphere
during daytime observation were within the range of uncertainty (k=2),
and that sensor orientation is the major source of uncertainty in the
RS92-SGP temperature measurement, while sensor albedo is the major source of
uncertainty for RS-11G. The relative humidity difference in the troposphere
was larger than the uncertainty (k=2) after the radiosondes had passed
through the cloud layer, and the temperature–humidity dependence correction
was the major source of uncertainty in RS-11G relative humidity measurement.
Uncertainties for all soundings were also statistically investigated. Most
nighttime temperature measurements for pressures of >10 hPa
were in agreement, while relative humidity in the middle troposphere
exhibited significant differences. Around half of all daytime temperature
measurements at pressures of ≤150 hPa and relative humidity
measurements around the 500 hPa level were not in agreement.
Ocean-driven millennial-scale variability of the Eurasian ice sheet during the last glacial period simulated with a hybrid ice-sheet–shelf model
Authors: Alvarez-Solas Jorge , Banderas Rubén , Robinson Alexander , Montoya Marisa
Published: June 2019

Abstract. The last glacial period (LGP; ca. 110–10 kyr BP) was marked by the existence of two types of abrupt climatic changes, Dansgaard–Oeschger (DO) and Heinrich (H) events.
Although the mechanisms behind these are not fully understood, it is generally accepted that the presence of ice sheets played an important role in their occurrence.
While an important effort has been made to investigate the dynamics and evolution of the Laurentide ice sheet (LIS) during this period, the Eurasian ice sheet (EIS) has not received much attention, in particular from a modeling perspective.
However, meltwater discharge from this and other ice sheets surrounding the Nordic seas is often implied as a potential cause of ocean instabilities that lead to glacial abrupt climate changes.
Thus, a better comprehension of the evolution of the EIS during the LGP is important to understand its role in glacial abrupt climate changes. Here we investigate the response of the EIS to millennial-scale climate variability during the LGP. We use a hybrid, three-dimensional, thermomechanical ice-sheet model that includes ice shelves and ice streams.
The model is forced off-line via a novel perturbative approach that, as opposed to conventional methods, clearly differentiates between the spatial patterns of millennial-scale and orbital-scale
climate variability. Thus, it provides a more realistic treatment of the forcing at millennial timescales. The effect of both atmospheric and oceanic variations are included.
Our results show that the EIS responds with enhanced ice discharge in phase with interstadial warming in the North Atlantic when forced with surface ocean temperatures.
Conversely, when subsurface ocean temperatures are used, enhanced ice discharge occurs both during stadials and at the beginning of the interstadials.
Separating the atmospheric and oceanic effects demonstrates the major role of the ocean in controlling the dynamics of the EIS on millennial timescales.
While the atmospheric forcing alone is only able to produce modest iceberg discharges, warming of the ocean leads to higher rates of iceberg discharges as a result of relatively strong basal melting at the margins of the ice sheet.
Our results clearly show the capability of the EIS to react to glacial abrupt climate changes, and highlight the need for stronger constraints on the ice sheet's glacial dynamics and climate–ocean interactions.
A new multi-variable benchmark for Last Glacial Maximum climate simulations
Authors: Cleator Sean F. , Harrison Sandy P. , Nichols Nancy K, , Prentice Iain Colin , Roulstone Ian
Published: June 2019

Abstract. We present a new global reconstruction of seasonal climates at the Last Glacial Maximum (LGM, 21,000 yr BP) made using 3-D variational data assimilation with pollen-based site reconstructions of six climate variables and the ensemble average of the PMIP3/CMIP5 simulations as a prior. We assume that the correlation matrix of the errors of the prior both spatially and temporally is Gaussian, in order to produce a climate reconstruction that is smoothed both from month to month and from grid cell to grid cell. The pollen-based reconstructions include mean annual temperature (MAT), mean temperature of the coldest month (MTCO), mean temperature of the warmest month (MTWA), growing season warmth as measured by growing degree days above a baseline of 5 °C (GDD5), mean annual precipitation (MAP) and a moisture index (MI), which is the ratio of MAP to mean annual potential evapotranspiration. Different variables are reconstructed at different sites, but our approach both preserves seasonal relationships and allows a more complete set of seasonal climate variables to be derived at each location. We further account for the ecophysiological effects of low atmospheric carbon dioxide concentration on vegetation in making reconstructions of MAP and MI. This adjustment results in the reconstruction of wetter climates than might otherwise be inferred by the vegetation composition. Finally, by comparing the error contribution to the final reconstruction, we provide confidence intervals on these reconstructions and delimit geographical regions for which the palaeodata provide no information to constrain the climate reconstructions. The new reconstructions will provide a robust benchmark for evaluation of the PMIP4/CMIP6 entry-card LGM simulations.
A new merge of global surface temperature datasets since the start of the
20th Century
Authors: Yun Xiang , Huang Boyin , Cheng Jiayi , Xu Wenhui , Qiao Shaobo , Li Qingxiang
Published: June 2019

Abstract. Global surface temperature (ST) datasets are the foundation for global climate change research. There are several global ST datasets developed by different groups in NOAA/NCEI，NASA/GISS and UKMO Hadley Centre & UEA/CRU. This study presents a new global ST dataset, the China Merged Surface Temperature (CMST) dataset. CMST is created by merging the China-Land Surface Air Temperature (C-LSAT1.3) with the sea surface temperature (SST) data from the Extended Reconstructed Sea Surface Temperature version 5 (ERSSTv5). The merge of C-LSAT and ERSSTv5 shows a high spatial coverage extended to the high latitudes and is more consistent with a reference of multi-datasets average in Polar Regions. Comparisons indicate that CMST is consistent with other existing global ST datasets in interannual-decadal variations and long-term trends at global, hemispheric, and regional scales from 1900 to 2017. Therefore CMST dataset can be used for global climate change assessment, monitoring, and detection. CMST dataset presented in this article is publicly available at: https://doi.pangaea.de/10.1594/PANGAEA.901295 (Yun et al., 2019) and has been published on the Climate Explorer website of the Royal Netherlands Meteorological Institute (KNMI) at: http://climexp.knmi.nl/select.cgi?id=someone@somewhere&field=cmst.
The Matsuno baroclinic wave test case
Authors: Shamir Ofer , Yacoby Itamar , Ziskin Ziv Shlomi , Paldor Nathan
Published: June 2019

Abstract. The analytic wave solutions obtained by Matsuno (1966) in his seminal
work on equatorial waves provide a simple and informative way of assessing
the performance of atmospheric models by measuring the accuracy with which
they simulate these waves. These solutions approximate the solutions of the
shallow-water equations on the sphere for low gravity-wave speeds such
as those of the baroclinic modes in the atmosphere. This is in contrast to
the solutions of the non-divergent barotropic vorticity equation, used in the
Rossby–Haurwitz test case, which are only accurate for high
gravity-wave speeds such as those of the barotropic mode. The proposed test case
assigns specific values to the wave parameters (gravity-wave speed, zonal
wave number, meridional wave mode and wave amplitude) for both planetary and
inertia-gravity waves, and suggests simple assessment criteria suitable for
zonally propagating wave solutions. The test is successfully applied to a
spherical shallow-water model in an equatorial channel and to a global-scale
model. By adding a small perturbation to the initial fields it is
demonstrated that the chosen initial waves remain stable for at least 100
wave periods. The proposed test case can also be used as a resolution
convergence test.
Observation operators for assimilation of satellite observations in fluvial inundation forecasting
Authors: Cooper Elizabeth S. , Dance Sarah L. , García-Pintado Javier , Nichols Nancy K. , Smith Polly J.
Published: June 2019

Abstract. Images from satellite-based synthetic aperture radar (SAR) instruments
contain large amounts of information about the position of floodwater during
a river flood event. This observational information typically covers a large
spatial area but is only relevant for a short time if water levels are
changing rapidly. Data assimilation allows us to combine valuable SAR-derived
observed information with continuous predictions from a computational
hydrodynamic model and thus to produce a better forecast than using the model
alone. In order to use observations in this way, a suitable observation
operator is required. In this paper we show that different types of
observation operators can produce very different corrections to predicted
water levels; this impacts the quality of the forecast produced. We
discuss the physical mechanisms by which different observation operators
update modelled water levels and introduce a novel observation operator for
inundation forecasting. The performance of the new operator is compared in
synthetic experiments with that of two more conventional approaches. The
conventional approaches both use observations of water levels derived from
SAR to correct model predictions. Our new operator is instead designed to use
backscatter values from SAR instruments as observations; such an approach has
not been used before in an ensemble Kalman filtering framework. Direct use of
backscatter observations opens up the possibility of using more information
from each SAR image and could potentially speed up the time taken to produce
observations needed to update model predictions. We compare the strengths and
weaknesses of the three different approaches with reference to the physical
mechanisms with which each of the observation operators allow data assimilation
to update water levels in synthetic twin experiments in an idealised domain.
SEMANTIC SEGMENTATION OF BUILDING IN AIRBORNE IMAGES
Authors: Huang S. , Nex F. , Lin Y. , Yang M. Y.
Published: June 2019

Abstract. Building is a key component to the reconstructing of LoD3 city modelling. Compared to terrestrial view, airborne datasets have more occlusions at street level but can cover larger area in the urban areas. With the popularity of the Deep Learning, many tasks in the field of computer vision can be solved in easier and efficiency way. In this paper, we propose a method to apply deep neural networks to building façade segmentation. In particular, the FC-DenseNet and the DeepLabV3+ algorithms are used to segment the building from airborne images and get semantic information such as, wall, roof, balcony and opening area. The patch-wise segmentation is used in the training and testing process in order to get information at pixel level. Different typologies of input have been considered: beside the conventional 2D information (i.e. RGB image), we combined 2D information with 3D features extracted from dense image matching point clouds to improve the performance of the segmentation. Results show that FC-DenseNet trained with 2D and 3D features achieves the best result, IoU up to 64.41%, it increases 5.13% compared to the result of the same model trained without 3D features.
RESNET-BASED TREE SPECIES CLASSIFICATION USING UAV IMAGES
Authors: Natesan S. , Armenakis C. , Vepakomma U.
Published: June 2019

Abstract. Tree species classification at individual tree level is a challenging problem in forest management. Deep learning, a cutting-edge technology evolved from Artificial Intelligence, was seen to outperform other techniques when it comes to complex problems such as image classification. In this work, we present a novel method to classify forest tree species through high resolution RGB images acquired with a simple consumer grade camera mounted on a UAV platform using Residual Neural Networks. We used UAV RGB images acquired over three years that varied in numerous acquisition parameters such as season, time, illumination and angle to train the neural network. To begin with, we have experimented with limited data towards the identification of two pine species namely red pine and white pine from the rest of the species. We performed two experiments, first with the images from all three acquisition years and the second with images from only one acquisition year. In the first experiment, we obtained 80% classification accuracy when the trained network was tested on a distinct set of images and in the second experiment, we obtained 51% classification accuracy. As a part of this work, a novel dataset of high-resolution labelled tree species is generated that can be used to conduct further studies involving deep neural networks in forestry.
POINT CLOUDS TO DIRECT INDOOR PEDESTRIAN PATHFINDING
Authors: Balado J. , Díaz-Vilariño L. , Arias P. , Frías E.
Published: June 2019

Abstract. Increase in building complexity can cause difficulties orienting people, especially people with reduced mobility. This work presents a methodology to enable the direct use of indoor point clouds as navigable models for pathfinding. Input point cloud is classified in horizontal and vertical elements according to inclination of each point respect to n neighbour points. Points belonging to the main floor are detected by histogram application. Other floors at different heights and stairs are detected by analysing the proximity to the detected main floor. Then, point cloud regions classified as floor are rasterized to delimit navigable surface and occlusions are corrected by applying morphological operations assuming planarity and taking into account the existence of obstacles. Finally, point cloud of navigable floor is downsampled and structured in a grid. Remaining points are nodes to create navigable indoor graph. The methodology has been tested in two real case studies provided by the ISPRS benchmark on indoor modelling. A pathfinding algorithm is applied to generate routes and to verify the usability of generated graphs. Generated models and routes are coherent with selected motor skills because routes avoid obstacles and can cross areas of non-acquired data. The proposed methodology allows to use point clouds directly as navigation graphs, without an intermediate phase of generating parametric model of surfaces.
INVESTIGATION INTO THE POTENTIAL OF SINGLE PHOTON AIRBORNE LASER SCANNING TECHNOLOGY
Authors: Bernard C. , Mills J. P. , Talaya J. , Remondino F.
Published: June 2019

Abstract. Following several years of incremental technological developments in airborne laser scanning, the field is currently witnessing potentially revolutionary change through the introduction of new technologies, namely Single Photon (SP) and Geiger-Mode (GM) lidar. These new sensors potentially provide more efficient approaches to perform high-resolution 3D mapping, but seemingly to the detriment of accuracy and noise. Despite concerns, the technology is perceived to offer higher efficiency with respect to conventional airborne laser scanning and additional 3D mapping capability in terms of swath width, spatial resolution, acquisition time and density of range returns. These developments have led to some European National Mapping and Cadastral Agencies (NMCAs) to consider a potential change in their production pipelines, while some mapping companies are contemplating upgrading their existing airborne sensor systems. However, few open datasets and experiences are available to inform such decisions, and the community is keen to learn more about the technology and its deployment for 3D territorial mapping. These facts and considerations motivated EuroSDR Commission 1 to launch a new initiative in 2018 to better understand, explore and report to its NMCA membership the developments in SP and GM technologies. This paper describes the activities that have thus far been conducted as part of this EuroSDR initiative, comprising: a global on-line questionnaire into awareness of the technology; a preliminary investigation into a Leica SPL100 dataset of Easton, USA; and a community workshop at which a proposal to run an international benchmarking exercise was discussed.
SIMULATING UNMANNED-AERIAL-VEHICLE BASED LASER SCANNING DATA FOR EFFICIENT MISSION PLANNING IN COMPLEX TERRAIN
Authors: Bremer M. , Wichmann V. , Rutzinger M. , Zieher T. , Pfeiffer J.
Published: June 2019

Abstract. In complex mountainous terrain the mapping efficiency is a crucial factor. Unmanned aerial vehicle (UAV) based laser scanning (ULS) has the capability for efficient mapping, as it allows realizing higher flight velocities, higher flying altitude above ground level (AGL) and larger distances between neighbouring flight strips, compared to image based techniques. However, fully utilising the efficiency of the system in mission planning (especially for complex terrain projects, where occlusions and differently inclined surfaces are present) is prone to miss the project requirements in terms of point density and strip overlap. Therefore, the numerical simulation of point densities is a helpful tool for realizing a reliable planning of scan coverage. We implemented a ray-tracing-based ULS-simulator, specifically designed for emulating the mechanism of a Riegl VUX-1LR laser scanner carried by a Riegl RiCOPTER. The simulator can consider copter and scanner motion, which makes it possible to generate synthetic scan data excluding or including the aircraft movement due to aerodynamics by using either planned trajectories from a flight planning software or recorded and post-processed trajectories from an inertial measurement unit (IMU). Laser shots are simulated by intersecting rays from the virtual scanner with a mesh-based digital surface model (DSM). The results show that the tool generates plausible synthetic laser point distributions. However, this is only the case, when aircraft aerodynamics are considered, as the effect of striping due to flight control corrections during the flight is very prominent. It can be shown that applying the presented tool for mission planning (without knowing the actual flight movements) has to consider an error margin of ±50pts/m2 in order to guarantee a compliance with the planned project requirements. Nevertheless, the consideration of terrain by a high resolution DSM, especially in complex terrain, improves the correlation between simulated and real point densities significantly.
Validating modeled critical crack length for crack propagation in the snow cover model SNOWPACK
Authors: Richter Bettina , Schweizer Jürg , Rotach Mathias W. , van Herwijnen Alec
Published: June 2019

Abstract. Data on snow stratigraphy and snow instability are of key importance for avalanche forecasting. Snow cover models can improve the spatial and temporal resolution of such data, especially if they also provide information on snow instability. Recently, a new stability criterion, namely a parameterization for the critical crack length, was implemented into the snow cover model SNOWPACK. To validate and improve this parameterization, we therefore used data from three years of field experiments performed close to two automatic weather station above Davos, Switzerland. Monitoring the snowpack on a weekly basis allowed to investigate limitations of the model. Based on 145 experiments we replaced two variables of the original parameterization, which were not sufficiently well modeled, with a fit factor thereby decreasing the normalized root mean square error from 1.80 to 0.28. With this fit factor, the improved parameterization accounts for the grain size resulting in lower critical crack lengths for snow layers with larger grains. This also improved an automatic weak layer detection method using a simple local minimum by increasing the probability of detection from 0.26 to 0.91 and decreased the false alarm ratio from 0.89 to 0.47.
Open Web annotation as collaborative learning
Authors: Kalir Jeremiah H.
Published: June 2019

This paper describes the use of open Web annotation (OWA) for collaborative learning among online communities. OWA is defined by the open standards, principles, and practices associated with the open Web. Specifically, this case study examines collaborative learning mediated by the OWA technology Hypothesis, a standards-compliant and open-source technology that situates collaboration in texts-as-contexts. Hypothesis OWA supports a repertoire of six collaborative learning practices: Affording multimodal expression, establishing connections across contexts, archiving activity, visualizing expertise and cognition, contributing to open educational resources, and fostering open educational practices. The use of Hypothesis OWA is then described in three online communities associated with scientific research and communication, educator professional development, and Web literacy and fact-checking. The article concludes by advancing three broad questions and related research agendas regarding how OWA as collaborative learning attends to linkages among formal and informal learning environments, the growth of both open educational resources and practices, and the use of open data as learning analytics.
Study of the influence of brewing water on selected analytes in beer
Authors: Punčochářová Lenka , Poří­zka Jaromí­r , Diviš Pavel , Štursa Václav
Published: June 2019

Brewing water is one of the basic raw materials for beer production and knowledge of its composition and pH is essential for the proper conduct of the entire brewing process. In this study, it was observed how the composition of water influences OG values, content of B vitamins, organic acids and iso-α-acids. For brewing, synthetic water was prepared by adding chemicals to deionized water. Models of hard (pH 8.47 ±0.08) and soft (pH 7.68 ±0.23) synthetic water were used for brewing pale bottom-fermented lager beers. Samples of wort, hopped wort, young beer and beer were collected during beer production. HPLC-DAD was used for B vitamins and iso-α-bitter acids quantification. Determination of organic acids was done by ion chromatography with conductivity detector. Obtained data were statistically processed with ANOVA (Analysis of Variance) and interval of confidence was set to 95%. According to the statistical analysis, water composition affects analytes content during beer production and in the final product. Hard water seemed to be a better extraction buffer and its composition (pH) positively affected some processes during brewing technology. One of them was obtaining higher OG values compared to soft water. The beer made from hard water also contained more B vitamins. Composition of brewing water had no influence neither on concentration of organic acids nor on iso-α-acids in conditions of homebrewing.
“A Loyal Heart to God and the Governor”: Missions and Colonial Policy in the Surinamese Saramaccan Mission (c. 1750–1813)
Authors: Cronshagen Jessica
Published: June 2019

This article argues that the idea of political neutrality did not work in the mission of the eighteenth-century Maroons in Surinam. The author outlines the extent to which the missionaries acted politically, made political decisions, used political quarrels for their own interests, and, for the main part, were used for the political interests of the different groups in Surinam. Colonial politics in Surinam were shaped by many different agents and networks: by the Dutch Society of Surinam and the colonial government, but also by indigenous tribes, Saramaccans, slaves, planters, merchants, officials, soldiers, and missionaries. Every daily practice could be read as a political act, as a representation of rebellion or imperialism. Under such circumstances, the idea of neutrality had to fail.
Divine Providence and the Dog in the Book of Tobit
Authors: Macatangay Francis M.
Published: June 2019

The presence of the dog is a puzzling narrative detail in the Book of Tobit. This study examines the canine presence in the story in light of divine providence and argues that the presence of the dog playing its assigned function in the story can point to the unseen reality that the divine creative order, which is the harbinger and bearer of divine providence, continues to hold albeit in hidden ways. Like the disguised Raphael, who personifies divine providence in the narrative, the inclusion of the dog in the story can be viewed as a concealed indication of the enduring aliveness of God’s life-giving and providential intentions for his people.
Prevalencia de cuadros depresivos y factores asociados en mujeres adultas de la Isla de Chiloé
Authors: Alvarado Rubén , Numhauser Jacobo
Published: June 2019

Su objetivo es describir la tasa de prevalencia instantánea de cuadros depresivos en mujeres de la Isla de Chiloé, la asociación con sintomatología y trastornos de tipo ansioso y somatoforme y estudiar la asociación con un conjunto de factores sociales. Se trata de un estudio transversal, con una muestra poblacional de tipo probabilística compuesta por 153 mujeres adultas, de 18 a 64 años, beneficiarias de Fonasa, que viven en la Isla Grande de Chiloé. La encuesta fue realizada en el domicilio por técnicos y profesionales de la salud previamente entrenados. Se utilizó una encuesta socio- económica precodificada y una escala para medir trastornos depresivos, ansiosos y somatoformes. Se encontró una prevalencia instantánea de 5,9 % (IC95 %  entre 2,2 % y 9,6 %) para trastornos depresivos y de 20,3% (IC95 % entre 13,9 % y 27,2 %) para cuadros subclínicos. Además, se observó una fuerte asociación entre los síntomas depresivos y los de tipo ansioso (r = 0,84) así como entre los síntomas depresivos y los de tipo somatoformes ( r = O, 67). Entre los factores sociales estudiados, sólo se encontró asociación estadísticamente significativa con el nivel educacional: las mujeres sin un cuadro clínico tenían una mayor cantidad de años de escolaridad que las que presentaban un cuadro depresivo (subclínico o un trastorno). Las mujeres que eran separadas y viudas, las que tenían un mayor número de hijos, las que vivían en zonas urbanas y las que referían tener un menor nivel de participación social, presentaban cifras más elevadas de trastornos depresivos, aunque esta diferencia no fue estadísticamente significativa . La prevalencia poblacional de trastornos depresivos es similar a la encontrada en otras zonas del país. La prevalencia poblacional en mujeres de cuadros depresivos de tipo subclínico no ha sido estudiada previamente en nuestro medio, pero la cifra es similar a la descrita en estudios en Estados Unidos y se discute la posibilidad de desarrollar programas preventivos. La estrecha asociación encontrada entre síntomas depresivos y los de tipo ansioso y somatoforme, tiene implicancias para la práctica clínica y para la organización de programas de atención. La asociación entre baja escolaridad y cuadros depresivos da relevancia al desarrollo de políticas sociales que buscan incrementar el nivel de escolaridad entre las jóvenes, ya que tendría -además- un efecto positivo y protector en su salud mental. Se discute la necesidad de avanzar en la elaboración de un modelo multidimensional para la explicación de estos cuadros depresivos.
La distribución gratuita de condones a trabajadoras sexuales en Ecuador: efectos en el comportamiento de compra
Authors: Fernández Mario
Published: June 2019

Los condones son considerados un método eficaz para evitar la propagación de infecciones de transmisión sexual. En Ecuador, un factor común en las políticas públicas de salud sexual es la entrega gratuita de condones a trabajadoras sexuales (TS). Esto ocurre junto con el asesoramiento sobre otras medidas preventivas y la importancia de las pruebas de detección del VIH. Este estudio busca determinar si la distribución gratuita de condones afecta la compra de los mismos y su uso consecuente. A través de una encuesta aplicada a 2.566 trabajadoras sexuales en ocho ciudades del Ecuador, se analiza el comportamiento de compra de condones. Los datos corresponden a las encuestas realizadas por el Proyecto de Prevención de Fronteras (PPF) en Ecuador en 2006. Dado que el acceso a las políticas públicas y a los condones gratuitos no es aleatorio, existen riesgos de sesgos de selección muestral. Para ello utilizamos un procedimiento de estimación Heckman en dos etapas. En la primera se analiza la probabilidad de comprar condones, y en la segunda, la cantidad de condones comprados. Se encuentra que por cada condón recibido gratuitamente, la TS compra uno más. Este resultado muestra la efectividad de las políticas de distribución cuando son acompañadas de componentes de asesoramiento e información.
Las diferencias sociales ante la muerte infantil en América Latina
Authors: Behm Rosas Hugo , Behm A. Ingrid
Published: June 2019

Publicado en Salud y Cambio, Año 6, Nº19, 1995
¿Hacia dónde va la medicina social?
Authors: Hevia Patricio
Published: June 2019

Publicado en Revista Mensaje. 1971, agosto; 20(201):362-65
Indicadores de salud bucal de la comuna de Las Guaitecas e Islas Huichas, región de Aysén
Authors: Méndez Fabián , Duffau Natalie , Pincheira Thomas , Soto Camila
Published: June 2019

Objetivo: Debido a la falta de información epidemiológica sobre salud bucal en la egión de Aysén y zonas aisladas de nuestro país, es que el objetivo de este estudio es evaluar los indicadores de salud bucal dependientes del COPD y ceod en la comuna de Las Guaitecas e Islas Huichas. Materiales y Métodos: Un total de 104 fichas odontológicas fueron consideradas en el estudio; 63 correspondientes a Guaitecas y 41 a Islas Huichas. 43 del programa de 6 años. 35 del programa odontológico de 12 años y 28 del programa de la gestante. Se registró el COPD y ceod según corresponda,calculando el Índice de Significancia de Caries, Porcentaje Libre de Caries, Prevalencia de Caries, con Historia de Caries y el Índice de Cuidados. Resultados: Los índices COPD, ceod, ambas comunidades, mientras que el índice de cuidados es bajo. Conclusiones: Todos los índices son deficientes al compararlos con los observados a nivel regional, nacional e internacional. El índice de cuidados demuestra una baja eficiencia estimada del sistema de salud odontológico. Ambas comunidades están muy lejos de alcanzar las metas internacionales respecto a salud bucal. El porcentaje de población que no tiene acceso a tratamientoodontológico integral, es muy alto en ambas islas.
Propuesta para una política de desarrollo profesional continuo del recurso médico de la atención primaria de Chile
Authors: Bass Camilo
Published: June 2019

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