Circular Buffer Research Articles

Built environment and physical activity: domain- and activity-specific associations among Brazilian adolescents

BackgroundPhysical activity is likely to be determined as a complex interplay between personal, interpersonal, and environmental factors. Studying the built environment involves expanding the focus from the individual perspective to a public health one. Therefore, the objetive of this study was to examine the association between the built environment and objectively-measured physical activity among youth.MethodsCross-sectional analysis of data from of a Brazilian birth cohort during adolescence. Physical activity was measured using accelerometers (GENEActiv) and self-report (International Physical Activity Questionnaire, long version). Participants’ home addresses were geocoded and built environment characteristics such as streets’ pattern and quality, and public open spaces attributes for physical activity practice were evaluated in a 500-m circular buffer surrounding their homes.ResultsA total of 3379 participants were included. Street lighting (β = 2.2; 95%CI: 0.5; 3.9) was positively associated with objectively-measured moderate-vigorous physical activity (MVPA) and proportion of paved streets and buffer’s average family income were associated with lower MVPA. Living near the beach increased the odds of leisure-time MVPA practice by 3.3 (95%CI: 1.37; 8.02) times. There was a built environment-by-socioeconomic status (SES) interaction for the associations with commuting physical activity; street lighting [Odds ratio (OR) = 1.22; 95%CI: 1.01; 1.47] and presence of cycle lanes (OR = 1.77; 95%CI: 1.05; 2.96) were positively associated with commuting physical activity only among the intermediate SES tertile.ConclusionBeachfront, street lighting, paved streets and cycle lanes were associated with physical activity patterns. This suggests that infrastructure interventions may influence physical activity levels of Brazilian adolescents.

Mapping and assessing crop diversity in the irrigated Fergana Valley, Uzbekistan

Crop diversity (e.g. the number of agricultural crop types and the level of evenness in area distribution) in the agricultural systems of arid Central Asia has recently been increased mainly to achieve food security of the rural population, however, not throughout the irrigation system. Site-specific factors that promote or hamper crop diversification after the dissolvent of the Soviet Union have hardly been assessed yet. While tapping the potential of remote sensing, the objective was to map and explain spatial patterns of current crop diversity by the example of the irrigated agricultural landscapes of the Fergana Valley, Uzbekistan. Multi-temporal Landsat and RapidEye satellite data formed the basis for creating annual and multi-annual crop maps for 2010–2012 while using supervised classifications. Applying the Simpson index of diversity (SID) to circular buffers with radii of 1.5 and 5 km elucidated the spatial distribution of crop diversity at both the local and landscape spatial scales. A variable importance analysis, rooted in the conditional forest algorithm, investigated potential environmental and socio-economic drivers of the spatial patterns of crop diversity. Overall accuracy of the annual crop maps ranged from 0.84 to 0.86 whilst the SID varied between 0.1 and 0.85. The findings confirmed the existence of areas under monocultures as well as of crop diverse patches. Higher crop diversity occurred in the more distal parts of the irrigation system and sparsely settled areas, especially due to orchards. In contrast, in water-secure and densely settled areas, cotton-wheat rotations dominated due to the state interventions in crop cultivation. Distances to irrigation infrastructure, settlements and the road network influenced crop diversity the most. Spatial explicit information on crop diversity per se has the potential to support policymaking and spatial planning towards crop diversification. Driver analysis as exemplified at the study region in Uzbekistan can help reaching the declared policy to increase crop diversity throughout the country and even beyond.

Improved pipelined wavelet implementation for filtering ECG signals

We present a novel algorithm for digital filtering of an electrocardiogram (ECG) signal received by both stationary and non-stationary sensors. The basic idea of digital ECG signal processing is to extract heartbeat frequencies, which are found to be normal in the range between 50 and 200 beats per min. The extracted heartbeat frequency is found to be irregular if the rate increases or decreases and serves as evidence for a diagnosis of a complex physiological condition. A lot of noise can be generated from the environment, including the electrical energy supply (50 or 60 Hz), breathing, physical movement, muscles etc. We experimented with several digital band pass filters including the finite response filter, Butterworth filter and a filter implementing the digital wavelet transformation. Classical programming of a digital wavelet transformation includes a lot of operations, which increase the algorithm complexity and, therefore, cannot be recommended for smartphones or other mobile devices, due to their limited resources, such as battery life, storage capacity, and processing power. In order to realize a solution that will run on a smartphone and wearable ECG sensor, we faced a challenge to enable a sufficient quality of service and develop an efficient algorithm that will preserve the mobile phone resources. We implemented a new improved wavelet filter, which uses a circular buffer and, when compared with the classical solution, it reduces the number of memory accesses and instructions that transfer values between data arrays. This algorithm is a highly efficient solution for a smartphone (mobile device) since it decreases the processing time 15–20 times and also saves battery life.

Enable back memory and global synchronization on LLC buffer

The last-level cache (LLC) shared by heterogeneous processors such as CPU and general-purpose graphics processing unit (GPGPU) brings new opportunities to optimize data sharing among them. Previous work introduces the LLC buffer, which uses part of the LLC storage as a FIFO buffer to enable data sharing between CPU and GPGPU with negligible management overhead. However, the baseline LLC buffer’s capacity is limited and can lead to deadlock when the buffer is full. It also relies on inefficient CPU kernel relaunch and high overhead atomic operations on GPGPU for global synchronization. These limitations motivate us to enable back memory and global synchronization on the baseline LLC buffer and make it more practical. The back memory divides the buffer storage into two levels. While they are managed as a single queue, the data storage in each level is managed as individual circular buffer. The data are redirected to the memory level when the LLC level is full, and are loaded back to the LLC level when it has free space. The case study of n-queen shows that the back memory has a comparative performance with a LLC buffer of infinite LLC level. On the contrary, LLC buffer without back memory exhibits 10% performance degradation incurred by buffer space contention. The global synchronization is enabled by peeking the data about to be read from the buffer. Any request to read the data in LLC buffer after the global barrier is allowed only when all the threads reach the barrier. We adopt breadth-first search (BFS) as a case study and compare the LLC buffer with an optimized implementation of BFS on GPGPU. The results show the LLC buffer has speedup of 1.70 on average. The global synchronization time on GPGPU and CPU is decreased to 38 and 60–5%, respectively.

Viscoelastic internal damping finite-difference model for musical instruments physical model sound production

A viscoelastic model for the internal damping of musical instrument parts, like membranes or plates is implemented within a Finite-Difference Time Domain (FDTD) method. Internal damping of wood, leather, nylon, mylar, glue, or varnish strongly change the timbre of musical instruments and the precise spectrum of this damping contributes strongly to the individual instrument character. The model assumes a complex, frequency-dependent and linear stiffness in the frequency domain, which is analytically transferred into the time-domain using a Laplace transform. The resulting mass-weighted restoring force integral of the respective membrane or plate differential equation is solved using a circular buffer accumulation method for each spatial node on the geometry, which is effective, as the model is implemented on a massive parallel Graphics Processing Unit (GPU). The model is able to reproduce arbitrarily shaped internal damping frequency responses with sharp bandwidth and fast response. The model is also able to reproduce other energy distribution problems, like energy loss or even energy supply by different parts of musical instruments through coupling, time-dependent energy loss and supply behavior, or nonlinear damping behavior, like amplitude-dependent loss strength. So also internal damping of metamaterials can be calculated with this model.

Modelling of Autosar Libraries for Large Scale Testing

We demonstrate a specific method and technology for model-based testing of large software projects with the QuickCheck tool using property-based specifications. Our specifications are very precise, state-full models of the software under test (SUT). In our approach we define (a) formal descriptions of valid function call sequences (public API), (b) postconditions that check the validity of each call, and (c) call-out specifications that define and validate external system interactions (SUT calling external API). The QuickCheck tool automatically generates and executes tests from these specifications. Commercially, this method and tool have been used to test large parts of the industrially developed automotive libraries based on the Autosar standard. In this paper, we exemplify our approach with a circular buffer specified by Autosar, to demonstrate the capabilities of the model-based testing method of QuickCheck. Our example is small compared to the commercial QuickCheck models, but faithfully addresses many of the same challenges.

Landscape heterogeneity reduces coyote predation on white‐tailed deer fawns

ABSTRACTCoyote (Canis latrans) predation on white‐tailed deer (Odocoileus virginianus) fawns in southeastern North America has led to deer population declines in some areas. Research or management efforts initiated in response to coyote predation on fawns have primarily focused on implementation of reduced antlerless deer harvest or coyote control to mitigate population declines. Vegetation characteristics may influence coyote hunting efficiency, but the potential influence of land cover at large scales in the southeastern United States is underexplored. We investigated whether mortality risk was affected by landscape characteristics within fawn home ranges for a sample of 165 fawns on the United States Department of Energy's Savannah River Site (SRS), South Carolina, 2007–2012. We monitored fawns every 8 hours to ≥4 weeks of age and 1–3 times daily to 12 weeks of age. We included only surviving or coyote‐predated fawns in the dataset. The most supported model describing hazard ratios included the length of edge (i.e., area where 2 land cover types joined) in fawn home ranges. Probability of coyote predation increased 1.26 times for each 968‐m decrease in edge within a fawn's simulated home range (29.1‐ha circular buffer) under this model. Further, fawns with the least edge in their home ranges were >2 times more likely to be depredated by a coyote than fawns with the greatest edge availability. Support for other models was relatively low, but informative variables (e.g., mean patch fractal dimension, Shannon's diversity index, mean forest patch size) supported a general trend that as fawn home ranges became more homogeneous and contained larger patches with less edge and fewer cover types, predation risk increased. These findings are consistent with similar work in the midwestern United States, despite landscape differences between regions. The combined weight of evidence suggests maintenance of a heterogeneous landscape consisting of relatively small dispersed patches may reduce fawn losses to coyotes. This information may also be used to identify areas susceptible to greater fawn predation rates across large spatial scales. However, the relatively long forestry rotation lengths and large scale of consistent forest management on the SRS are uncommon in the southeastern United States and the mechanism for the pattern we observed is unclear. Therefore, our results may not be applicable to sites with different forest management practices. © 2017 The Wildlife Society.

Circular Buffer Rate-Matched Polar Codes

A practical rate-matching system for constructing rate-compatible polar codes is proposed. The proposed polar code circular buffer rate-matching is suitable for transmissions on communication channels that support hybrid automatic repeat request (HARQ) communications, as well as for flexible resource-element rate-matching on single transmission channels. Our proposed circular buffer rate matching scheme also incorporates a bit-mapping scheme for transmission on bit-interleaved coded modulation (BICM) channels using higher order modulations. An interleaver is derived from a puncturing order obtained with a low complexity progressive puncturing search algorithm on a base code of short length, and has the flexibility to achieve any desired rate at the desired code length, through puncturing or repetition. The rate-matching scheme is implied by a two-stage polarization, for transmission at any desired code length, code rate, and modulation order, and is shown to achieve the symmetric capacity of BICM channels. Numerical results on AWGN and fast fading channels show that the rate-matched polar codes have a competitive performance when compared to the spatially-coupled quasi-cyclic LDPC codes or LTE turbo codes, while having similar rate-dematching storage and computational complexities.

Land-use regression with long-term satellite-based greenness index and culture-specific sources to model PM2.5 spatial-temporal variability

This study utilized a long-term satellite-based vegetation index, and considered culture-specific emission sources (temples and Chinese restaurants) with Land-use Regression (LUR) modelling to estimate the spatial-temporal variability of PM2.5 using data from Taipei metropolis, which exhibits typical Asian city characteristics. Annual average PM2.5 concentrations from 2006 to 2012 of 17 air quality monitoring stations established by Environmental Protection Administration of Taiwan were used for model development. PM2.5 measurements from 2013 were used for external data verification. Monthly Normalized Difference Vegetation Index (NDVI) images coupled with buffer analysis were used to assess the spatial-temporal variations of greenness surrounding the monitoring sites. The distribution of temples and Chinese restaurants were included to represent the emission contributions from incense and joss money burning, and gas cooking, respectively. Spearman correlation coefficient and stepwise regression were used for LUR model development, and 10-fold cross-validation and external data verification were applied to verify the model reliability. The results showed a strongly negative correlation (r: −0.71 to −0.77) between NDVI and PM2.5 while temples (r: 0.52 to 0.66) and Chinese restaurants (r: 0.31 to 0.44) were positively correlated to PM2.5 concentrations. With the adjusted model R2 of 0.89, a cross-validated adj-R2 of 0.90, and external validated R2 of 0.83, the high explanatory power of the resultant model was confirmed. Moreover, the averaged NDVI within a 1750 m circular buffer (p < 0.01), the number of Chinese restaurants within a 1750 m buffer (p < 0.01), and the number of temples within a 750 m buffer (p = 0.06) were selected as important predictors during the stepwise selection procedures. According to the partial R2, NDVI explained 66% of PM2.5 variation and was the dominant variable in the developed model. We suggest future studies consider these three factors when establishing LUR models for estimating PM2.5 in other Asian cities.

Efficient PCIe transmission for Multi-Channel video using dynamic splicing and conditional prefetching

PCI Express (PCIe) interface has been extensively used in high-speed digital systems for multimedia communication. With the migration of the video processing algorithms from host to embedded hardware, multi-channel video capturing systems will produce not only different channels of raw video data but also different types of auxiliary data, such as analyzed data and compressed stream. In order to display multi-channel video in real-time and explore the auxiliary data, conventional transmission strategies are no longer applicable, due to the fact that heterogeneous data will cause frequent interactions and lead to the waste of PCIe bandwidth. In this paper, an efficient PCIe transmission method for multi-channel video is presented. Firstly, for the transmission of multi-type video data, a dynamic splicing mechanism is proposed to combine the video analyzed data and the compressed stream with the raw video to avoid the individual transmission of the auxiliary data. Secondly, as the spliced data are from different channels, a conditional prefetching mechanism is employed to determine whether there exists any entire video frame in other channel buffers, so that multi-channel video data can be transmitted possibly at one time. Finally, in the host-side driver, direct kernel buffer access technique is used to improve the application I/O request packet (IRP) performance. And to ensure the transmission efficiency of the conditional prefetching, DMA circular queue buffer and timer self-feedback monitor techniques are designed to avoid the possible visit bursts and abnormal interruptions. Experimental results demonstrate that compared with the conventional methods, the proposed method reduces the interrupt interactions by 60%, increases the transmission channel number by 94%, and also increases the application IRP number by 54%. The peak transmission speed of PCIe is up to 155 MB/s, which can meet 7 channels 704 × 576 YUV raw video and its auxiliary data transmission requirements using one 1-lane PCIe endpoint.

Macrohabitat Composition Surrounding Successful and Depredated Northern Bobwhite Nests

Relationships among macrohabitat and depredation of northern bobwhite (Colinus virginianus) nests are poorly understood. Yet, macrohabitat composition may influence the nest predator community and, therefore, the vulnerability of northern bobwhite nests to depredation. We determined if macrohabitat composition surrounding bobwhite nests influenced nest placement, nest success, and which predators were responsible for depredating nests. We characterized macrohabitats at 2 scales, 8 and 16 ha, by surrounding both bobwhite nests, and an equal number of random locations, with a circular buffer. Random points were placed within the area used by bobwhites on our study area. We then determined the acreage of each macrohabitat category within each circular buffer to determine the macrohabitat composition. Macrohabitat categories included hardwood forested drains, upland pine forests burned in March of the same calendar year, upland pine forests burned in March of the previous calendar year, and fields. We documented nest predators using infrared video cameras placed at the nest site. We monitored 104 bobwhite nests on Tall Timbers Research Station (TTRS) during 1999 and 2000. Size of the circular buffer around nests did not qualitatively affect results. Area (ha) of upland pine forests and fields were similar at depredated nests, hatched nests, and random locations. However, there was an average of 81% and 56% more area of hardwood drain in the circular buffers associated with random locations than at successful and depredated nests, respectively. Area of upland pine forests and fields were similar for nests depredated by raccoon (Procyon lotor), armadillo (Dasypus novemcinctus) and snake (Elaphus spp.). However, there was an average of 6.1 and 3.3 times more area of hardwood drain surrounding nests that were depredated by snakes relative to nests depredated by raccoons and armadillos, respectively. While our sample sizes were low, bobwhites exhibited a tendency to place nests in landscapes with less hardwood drain than were generally available on the study area. Macrohabitat surrounding nests influenced the type of nest predator to depredate nests. To minimize depredation of bobwhite nests by snakes, we suggest nesting cover should be developed away from drain edges.

Residential neighbourhood greenspace is associated with reduced risk of incident diabetes in older people: a prospective cohort study

BackgroundThree cross sectional studies suggest that neighbourhood greenspace may protect against incident diabetes. This study uses data from a longitudinal study with a large sample size to investigate the association between greenspace and the occurrence of incident diabetes over time.MethodsData was from the European Prospective Investigation of Cancer Norfolk, UK, cohort, recruitment 1993–2007 (N = 23,865). Neighbourhoods were defined as 800 m circular buffers around participants’ home locations, according to their home postcode (zip code). Greenspace exposure was defined as the percentage of the home neighbourhood that was woodland, grassland, arable land, mountain, heath and bog, according to the UK Land Cover Map. Cox proportional hazards regression examined the association between neighbourhood greenspace exposure and incident diabetes. The population attributable fraction assessed the proportion of diabetes cases attributable to exposure to least green neighbourhoods. Mediation analysis assessed if physical activity explained associations between greenspace and diabetes. Interaction analysis was used to test for the modifying effect of rurality and socio-economic status on the relationship between greenspace and diabetes. Models were adjusted for known and hypothesised confounders.ResultsThe mean age of participants was 59 years at baseline and 55.1% were female. The mean follow-up time was 11.3 years. Individuals living in the greenest neighbourhood quartile had a 19% lower relative hazard of developing diabetes (HR 0.81; 95% CI 0.67, 0.99; p = 0.035; linear trend p = 0.010). The hazard ratio remained similar (HR 0.81; 95% CI 0.65, 0.99; p = 0.042) after adjusting for age, sex, BMI, whether a parent had been diagnosed with diabetes and socio-economic status at the individual and neighbourhood level. A HR of 0.97 was attributed to the pathway through physical activity in a fully adjusted model, although this was non-significant (95% CI 0.88, 1.08; p = 0.603). The incidence of diabetes in the least green neighbourhoods (with 20% greenspace on average) would fall by 10.7% (95% CI −2.1%, 25.2%; p = 0.106) if they were as green as the average neighbourhood observed across the whole cohort (59% greenspace on average). There were no significant interactions between rurality or socio-economic status and level of greenspace.ConclusionsGreener home neighbourhoods may protect against risk of diabetes in older adults, although this study does not support a mediation role for physical activity. Causal mechanisms underlying the associations require further investigation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3833-z) contains supplementary material, which is available to authorized users.

Interplay of takeaway food outlet exposure and income on diet and obesity: a cross-sectional study in UK Biobank

BackgroundThe proliferation of takeaway food outlets has been called a public health problem by Public Health England and the Chief Medical Officer for England. Evidence indicates that the density of takeaway outlets in neighbourhoods can promote unhealthy eating and obesity. But takeaway outlets tend to cluster in deprived areas, and vulnerability to unhealthy food environments might vary across social groups. This study examined the interplay between exposure to takeaway outlets and individual-level socioeconomic position in relation to diet and obesity. MethodsThis cross-sectional study included UK Biobank participants based in Greater London (n=51 361) aged 38–72 years with valid height and weight data, food frequency data, and food environment exposures. Food environment exposures were estimated using geographic information systems and food outlet data from UKMap, as counts of outlets by type, within one-mile radius Euclidean (circular) buffers centred on each participant's home address. Our primary exposure was the number of takeaway outlets as a proportion of all food outlets. Participants were jointly classified on the basis of household income (four groups) and quartile of neighbourhood takeaway outlet proportion to create 16 exposure groups. Regression models estimated the odds of frequent processed meat consumption and obesity. We calculated relative excess risk due to interaction (RERI), relative to a single reference group. Participant data were collected during 2005–13 and analysed in 2016. FindingsBoth income and takeaway exposure were systematically associated with frequent consumption of processed meat and obesity. In mutually adjusted models, lowest-income participants were more likely than highest-income participants to be obese (odds ratio 1·53, 95% CI 1·38–1·69); and relative to those least exposed, highest takeaway exposure was also associated with obesity (1·76, 1·61–1·91). In additive models, the combination of lowest income and highest takeaway exposure was associated with substantially increased odds of obesity (2·75, 2·33–3·24), with the RERI indicating significant interaction. Results were similar in diet analyses. InterpretationWe have confirmed the findings of earlier work showing independent associations between income, neighbourhood takeaway outlet exposure, and diet and adiposity. Moreover, we provide evidence of the double burden of low income and an unhealthy neighbourhood food environment, resulting in higher rates of unhealthy diet and obesity. FundingBritish Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, National Institute for Health Research, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration.

Predictors of breeding site occupancy by amphibians in montane landscapes

ABSTRACTEcological relationships and processes vary across species’ geographic distributions, life stages and spatial, and temporal scales. Montane landscapes are characterized by low wetland densities, rugged topographies, and cold climates. Consequently, aquatic‐dependent and low‐vagility ectothermic species (e.g., pool‐breeding amphibians) may exhibit unique ecological associations in montane landscapes. We evaluated the relative importance of breeding‐ and landscape‐scale features associated with spotted salamander (Ambystoma maculatum) and wood frog (Lithobates sylvaticus) wetland occupancy in Maine's Upper Montane‐Alpine Zone ecoregion, and we determined whether models performed better when the inclusive landscape‐scale covariates were estimated with topography‐weighted or circular buffers. We surveyed 135 potential breeding sites during May 2013–June 2014 and evaluated environmental relationships with multi‐season implicit dynamics occupancy models. Breeding site occupancy by both species was influenced solely by breeding‐scale habitat features. Spotted salamander occupancy probabilities increased with previous or current beaver (Castor canadensis) presence, and models generally were better supported when the inclusive landscape‐scale covariates were estimated with topography‐weighted rather than circular buffers. Wood frog occupancy probabilities increased with site area and percent shallows, but neither buffer type was better supported than the other. Model rank order and support varied between buffer types, but model inferences did not. Our results suggest pool‐breeding amphibian conservation in montane Maine include measures to maintain beaver populations and large wetlands with proportionally large areas of shallows ≤1‐m deep. Inconsistencies between our study and previous studies substantiate the value of region‐specific research for augmenting species’ conservation management plans and suggest the application of out‐of‐region inferences may promote ineffective conservation. © 2016 The Wildlife Society.

Combining spatial data with survey data improves predictions of boundaries between settlements

Studies of land-use change often require the combination of socioeconomic survey data with spatially continuous maps of land-cover change. One approach is to define maps of land ownership, assuming that all land-use change can be attributed to the owners or managers of each parcel of land. Unfortunately, records of administrative boundaries between towns and villages are commonly unavailable in developing countries and prohibitively costly or time consuming to map for individual projects. However, point locations of the settlements themselves can be obtained easily from existing maps or remotely-sensed imagery. In this paper we compare three methods – circular buffers, unweighted Voronoi polygons (sometimes referred to as Thiessen polygons) and multiplicatively weighted Voronoi polygons – for estimating boundaries between villages in an agricultural landscape in West Africa. The benefits and limitations of each approach are discussed, and their accuracy assessed using 98 independently collected GPS coordinates of village boundaries. We present a novel method for generating and optimising weights for multiplicatively weighted Voronoi polygons using survey data of village sizes from a subset of villages. By using both spatial information and survey data from villages, we show that multiplicatively weighted Voronoi polygons outperform other methods of predicting village boundaries, and increase the correlation coefficient between surveyed village area and mapped areas from 0.18 to 0.68 compared with more commonly used unweighted Voronoi polygons. Our method of weighting Voronoi polygons can be implemented with data and software commonly available to researchers and non-governmental organisations.

Modeling human population patterns on tree density

In order to evaluate the possible correlation between the tree density and the human population density, the forested area in Nav Asalem districtlocated in Guilan Province was selected. The descriptors of tree number and basal area per hectare as well as the stand density index were used to determine the tree density, which was conducted from a 2014 forest inventory including 62 cluster (558 plots) systematically scattered over 30 % of the forest area. In addition, to determine the density of the human population, circular buffers at intervals of 1 to 7 km from the center of each cluster was considered and population density of each layer was calculated using buffering functions. Statistical results showed that the average basal area, average number of trees and the average stand density index was 23.16 m 2 /ha, 243 per ha and 178.25 respectively and also different human population density in each buffer. Using Pearson correlation test indicated a significant negative correlation between the stand density index and basal area (DBH >15 cm) with human population density. There was no significant relationship between the number of trees per hectare and the human population density except at 7 km. This findings support studies regarding the disturbance has strong correlative with the number of residents per unit area at up to 7 km from clusters and greater control on anthropogenic interventions should be the main priority of sustainable forestry in Hyrcanian forests of northern Iran. Due to the existence of an effective relationship between the components of the tree density and human population in the forest, policy-makers and planners of natural resources could benefit management patterns appropriate to above components to achieve sustainable management.

The Imager for Sprites and Upper Atmospheric Lightning (ISUAL)

AbstractThe Imager for Sprites and Upper Atmospheric Lightning (ISUAL) was the first specifically dedicated instrument to observe lightning‐induced transient luminous events (TLE): sprites, elves, halos, and gigantic jets from space. The Imager is an intensified CCD system operating in the visible wavelength region with a filter wheel to select from six positions with filters. The Imager has a 5° × 20° (vertical times horizontal) field of view. The spectrophotometer (SP) is populated with six photometers with individual filters for emissions from the far ultraviolet to the near infrared. An array photometer with two channels operating in the blue and red provides altitude profiles of the emission over 16 altitude bins each. The Associated Electronics Package (AEP) controls instrument functions and interfaces with the spacecraft. ISUAL was launched 21 May 2004 into a Sun‐synchronous 890 km orbit on the Formosat‐2 satellite and has successfully been collecting data ever since. ISUAL is running on the nightside of the orbit and is pointed to the east of the orbit down toward the limb. The instrument runs continuously and writes data to a circular buffer. Whenever the SP detects a sudden signal increase above a preset threshold, a trigger signal is generated that commands the system to keep the data for about 400 ms starting from ~50 ms before the trigger. Over its lifetime of ~11 years the system recorded thousands of TLE and also successfully observed aurora and airglow.

Spatial and Temporal Hot Spots of Aedes albopictus Abundance inside and outside a South European Metropolitan Area.

Aedes albopictus is a tropical invasive species which in the last decades spread worldwide, also colonizing temperate regions of Europe and US, where it has become a public health concern due to its ability to transmit exotic arboviruses, as well as severe nuisance problems due to its aggressive daytime outdoor biting behaviour. While several studies have been carried out in order to predict the potential limits of the species expansions based on eco-climatic parameters, few studies have so far focused on the specific effects of these variables in shaping its micro-geographic abundance and dynamics. The present study investigated eco-climatic factors affecting Ae. albopictus abundance and dynamics in metropolitan and sub-urban/rural sites in Rome (Italy), which was colonized in 1997 and is nowadays one of the most infested metropolitan areas in Southern Europe. To this aim, longitudinal adult monitoring was carried out along a 70 km-transect across and beyond the most urbanized and densely populated metropolitan area. Two fine scale spatiotemporal datasets (one with reference to a 20m circular buffer around sticky traps used to collect mosquitoes and the second to a 300m circular buffer within each sampling site) were exploited to analyze the effect of climatic and socio-environmental variables on Ae. albopictus abundance and dynamics along the transect. Results showed an association between highly anthropized habitats and high adult abundance both in metropolitan and sub-urban/rural areas, with “small green islands” corresponding to hot spots of abundance in the metropolitan areas only, and a bimodal seasonal dynamics with a second peak of abundance in autumn, due to heavy rains occurring in the preceding weeks in association with permissive temperatures. The results provide useful indications to prioritize public mosquito control measures in temperate urban areas where nuisance, human-mosquito contact and risk of local arbovirus transmission are likely higher, and highlight potential public health risks also after the summer months typically associated with high mosquito densities.

A FAST AND FLEXIBLE METHOD FOR META-MAP BUILDING FOR ICP BASED SLAM

Abstract. Recent developments in LiDAR sensors make mobile mapping fast and cost effective. These sensors generate a large amount of data which in turn improves the coverage and details of the map. Due to the limited range of the sensor, one has to collect a series of scans to build the entire map of the environment. If we have good GNSS coverage, building a map is a well addressed problem. But in an indoor environment, we have limited GNSS reception and an inertial solution, if available, can quickly diverge. In such situations, simultaneous localization and mapping (SLAM) is used to generate a navigation solution and map concurrently. SLAM using point clouds possesses a number of computational challenges even with modern hardware due to the shear amount of data. In this paper, we propose two strategies for minimizing the cost of computation and storage when a 3D point cloud is used for navigation and real-time map building. We have used the 3D point cloud generated by Leica Geosystems's Pegasus Backpack which is equipped with Velodyne VLP-16 LiDARs scanners. To improve the speed of the conventional iterative closest point (ICP) algorithm, we propose a point cloud sub-sampling strategy which does not throw away any key features and yet significantly reduces the number of points that needs to be processed and stored. In order to speed up the correspondence finding step, a dual kd-tree and circular buffer architecture is proposed. We have shown that the proposed method can run in real time and has excellent navigation accuracy characteristics.

A FAST AND FLEXIBLE METHOD FOR META-MAP BUILDING FOR ICP BASED SLAM

Recent developments in LiDAR sensors make mobile mapping fast and cost effective. These sensors generate a large amount of data which in turn improves the coverage and details of the map. Due to the limited range of the sensor, one has to collect a series of scans to build the entire map of the environment. If we have good GNSS coverage, building a map is a well addressed problem. But in an indoor environment, we have limited GNSS reception and an inertial solution, if available, can quickly diverge. In such situations, simultaneous localization and mapping (SLAM) is used to generate a navigation solution and map concurrently. SLAM using point clouds possesses a number of computational challenges even with modern hardware due to the shear amount of data. In this paper, we propose two strategies for minimizing the cost of computation and storage when a 3D point cloud is used for navigation and real-time map building. We have used the 3D point cloud generated by Leica Geosystems's Pegasus Backpack which is equipped with Velodyne VLP-16 LiDARs scanners. To improve the speed of the conventional iterative closest point (ICP) algorithm, we propose a point cloud sub-sampling strategy which does not throw away any key features and yet significantly reduces the number of points that needs to be processed and stored. In order to speed up the correspondence finding step, a dual kd-tree and circular buffer architecture is proposed. We have shown that the proposed method can run in real time and has excellent navigation accuracy characteristics.