Ground Position Research Articles

The Influence of Electrode Properties on Induced Voltage Gradient Along the Rat Optic Nerve.

Significant interest exists in the potential of electric field (EF) application to be developed into a technology to direct neuronal regeneration. In vitro, EFs were shown to direct the growth of retinal ganglion cell (RGC) axons, the neurons that make up the optic nerve. As larger EF gradients were shown to direct more efficient growth, investigations into the most effective stimulation strategies that can generate the greatest voltage gradient are needed before EF application can be developed into a technology to direct optic nerve regeneration in vivo. We performed ex-vivo experiments to compare the ability of different electrode materials, platinum vs. tungsten, to generate an EF gradient along the rat optic nerve. Platinum electrodes at both source and ground positions were found to generate the greatest voltage gradient along the optic nerve. Experimental results were used to inform an equivalent computational model of the optic nerve, which was subsequently employed to predict more effective electrode pair combinations. Our results confirmed that the platinum-platinum electrode pair generates the maximum voltage gradient which are highly dependent on electrode size and electrode-electrolyte interfaces. This computational platform can serve as a foundation for the development of electrical stimulation therapies for nerve regeneration.

Planning Satellite Swarm Measurements for Earth Science Models: Comparing Constraint Processing and MILP Methods

We compare two planner solutions for a challenging Earth science application to plan coordinated measurements (observations) for a constellation of satellites. This problem is combinatorially explosive, involving many degrees of freedom for planner choices. Each satellite carries two different sensors and is maneuverable to 61 pointing angle options. The sensors collect data to update the predictions made by a high-fidelity global soil moisture prediction model. Soil moisture is an important geophysical variable whose knowledge is used in applications such as crop health monitoring and predictions of floods, droughts, and fires. The global soil-moisture model produces soil-moisture predictions with associated prediction errors over the globe represented by a grid of 1.67 million Ground Positions (GPs). The prediction error varies over space and time and can change drastically with events like rain/fire. The planner's goal is to select measurements which reduce prediction errors to improve future predictions. This is done by targeting high-quality observations at locations of high prediction-error. Observations can be made in multiple ways, such as by using one or more instruments or different pointing angles; the planner seeks to select the way with the least measurement-error (higher observation quality). In this paper we compare two planning approaches to this problem: Dynamic Constraint Processing (DCP) and Mixed Integer Linear Programming (MILP). We match inputs and metrics for both DCP and MILP algorithms to enable a direct apples-to-apples comparison. DCP uses domain heuristics to find solutions within a reasonable time for our application but cannot be proven optimal, while the MILP produces provably optimal solutions. We demonstrate and discuss the trades between DCP flexibility and performance vs. MILP's promise of provable optimality.

Preliminary Application of Space-Based Remote Sensing and Geospatial Technology for Investigation on the Geo-Environmental Consequences of Cyclone Aila 2009 in the NW Bangladesh

Climate change phenomena have become a great concern in the context of global change and increased frequency and magnitude of natural disasters throughout the world in the recent time. Natural disasters like floods, cyclones, storm surges etc. often cause significant losses of life, large-scale economic and social impacts, and considerable environmental damages. This paper dealt with study on the overall methodological development to investigate the consequences of climate change extremities particularly, the after effects of cyclone using Remote Sensing (RS) and Geographic Information System (GIS) technology. In this connection, individual functional components have been investigated, tested and verified. Time series multi-sensor satellite data particularly of Landsat, World view (from Google origin) have been utilized to infer information on the consequences of Cyclone Aila 2009 hitting part of southwestern Bangladesh as a test case under the present study. Information retrieval mechanism utilized is based on specially designed methodological framework using satellite-based RS technology along with GIS. Developed technical approach consists of a three-fold components – (i) Establishment of input foundation layer with high spatial details to support characterization, recognition and identification of important surface features using high resolution satellite data; (ii) Effective operational procedure to process, analyze, interpret and finally to archive the retrieved information; (iii) Functional computations were made using spatial modeler language (SML) programming environment under ERDAS Imagine image processing software. Satellite image processing, analysis operation together with image-based spectral characterization of surface features under different stressing conditions etc. have been exercised to derive useful surface information. Specially designed geospatial database has been established in GIS using ArcInfo professional software. Varieties of geospatial data from diverse sources have been incorporated categorically as column-based attributes in GIS. Dual spatial data layers have been generated in GIS for two different dates representing the pre-cyclone and post-cyclone time sequences utilizing appropriate high spatial resolution satellite images. Finally, a geospatial image-based combinational technique has been utilized employing high temporal and moderate spatial resolution time series satellite data with low temporal and high spatial resolution satellite data. Such an operation results in an improved spatial and temporal resolution of output products enabling capture of dynamics of surface features in the spatiotemporal domain providing more precision and details in the output. This study has been supplemented with necessary Ground Position System (GPS)-based ground truthing, selected field data collection and field-based group discussions outcomes.

Vehicle Positioning and Navigation in Asynchronous Navigation System

A Pseudo-satellite system that transmits signals similar to GNSS can provide positioning services in places where GNSS signals are not captured and have enormous potential for indoor machine system and airports. Different paths of the device have different carrier phase initial solution positioning accuracy. Existing methods rely on measuring instruments or use many coordinate points for solving ambiguity resolution (AR), which creates inconvenience for real-time ground positioning. This study aims to find a new on-the-fly (OTF) method to achieve high accuracy and convenient positioning. A new method is proposed based on a two-difference observation model for ground-based high-precision point positioning. We used an adaptive particle swarm algorithm to solve the initial solution, followed by a nonlinear least-squares method to optimize the localization solution. It is free of priori information or measuring instruments. We designed several different paths, such as circular trajectory and square trajectory, to study the positioning accuracy of the solution. Simulation experiments with different trajectories showed that geometric changes significantly impact solutions. In addition, it does not require precise time synchronization of the base stations, making the whole system much easier to deploy. We built a real-world pseudo-satellite system and used a multi-sensor crewless vehicle as a receiver. Real-world experiments showed that our approach could achieve centimeter-level positioning accuracy in applications.

The ‘onto-logics’ of perspectival multi-naturalism: A realist critique

In this article, I argue for a realist anthropology based on the recognition of mind-independent reality; pitching this premise against concerted anti-dualist tendencies in contemporary anthropological thinking. I spell out core analytical entailments of these, in my view, profoundly conflicting premises. In particular, I focus on perspectival multi-naturalism, arguing that despite adherents’ claims to reinvigorate studies of ‘ontology’, this approach instead exaggerates epistemological dimensions. When assessed from a realist stance, its ground position engenders a series of epistemic fallacies by which the ontological is, effectively, subordinated under epistemology. Advocates’ reluctance to appreciate a distinction between mind and mind-independent reality entails a profound contraction of perspective in terms of empirical and methodological scope, and, analytically, a disregard for ontological complexity and depth, thus curtailing the importance of anthropology in wider academic discourse.

壁面近傍で低空ホバリングするクアッドロータの吹き返しが回転翼の誘導流れに与える影響

One of the problems with multirotors is that when flying near a wall, such as during infrastructure inspections, the companion flow passing through the rotor blades is blown back by the ground or wall surface, causing instability in the flight attitude of the aircraft(1)(2). As a previous study on this phenomenon, as part of the development of a quadrotor capable of autonomous flight even in complex narrow spaces, we focused on a small quadrotor with four rotors among multi-rotors and investigated the effect on aerodynamic characteristics when hovering near a wall, and found that even at heights outside the ground effect, the direction and position of sidewalls Ground effect The results showed that even at heights outside the ground effect, the direction and position of the sidewalls increased the thrust of the wall-side rotor due to the blowback effect, causing the aircraft to tilt (roll) at some positions. In this study, to clarify the effect of the wake interference of quad rotor on the induced flow, we investigated the tip vortex trajectry and the induced flow velocity in the high thrust and rolling region(posture tilted backward against the wall) using a high-speed camera, a hot-wire anemometer, respectively. We show some of reasons to increase the thurust of wall side roters.

Knowing Your Mind by Making Up Your Mind Without Changing Your Mind, Too Much

At the center of much contemporary work on self-knowledge of our attitudes is a debate between Agentialists and Empiricists. Empiricists hold that first-person knowledge of one’s own attitudes possesses a broadly empirical basis, such as observation or inference. Agentialists insist that an account of self-knowledge must make sense of the intimate connection between knowing one’s attitudes and actively forming them in response to reasons. But it is plausible to suppose that a psychologically realistic account of self-knowledge will emphasize both active and passive elements. Focusing on the idea that we form self-ascriptions of belief on the basis of active deliberation, this paper outlines such a middle ground position.

Preliminary Application of Space-based Remote Sensing and Geospatial Technology for Investigation on the Geo-environmental Consequences of Cyclone Aila 2009 in the Bangladesh

Climate change phenomena have become a great concern in the context of global change and increased frequency and magnitude of natural disasters throughout the world in the recent time. Natural disasters like floods, cyclones, storm surges etc. often cause significant losses of life, large-scale economic and social impacts, and considerable environmental damages. This paper dealt with study on the overall methodological development to investigate the consequences of climate change extremities particularly, the after effects of cyclone using Remote Sensing (RS) and Geographic Information System (GIS) technology. In this connection, individual functional components have been investigated, tested and verified. Time series multi-sensor satellite data particularly of Landsat, World view (from Google origin) have been utilized to infer information on the consequences of Cyclone Aila 2009 hitting part of southwestern Bangladesh as a test case under the present study. Information retrieval mechanism utilized is based on specially designed methodological framework using satellite-based RS technology along with GIS. Developed technical approach consists of a three-fold components – (i) Establishment of input foundation layer with high spatial details to support characterization, recognition and identification of important surface features using high resolution satellite data; (ii) Effective operational procedure to process, analyze, interpret and finally to archive the retrieved information; (iii) Functional computations were made using spatial modeler language (SML) programming environment under ERDAS Imagine image processing software. Satellite image processing, analysis operation together with image-based spectral characterization of surface features under different stressing conditions etc. have been exercised to derive useful surface information. Specially designed geospatial database has been established in GIS using ArcInfo professional software. Varieties of geospatial data from diverse sources have been incorporated categorically as column-based attributes in GIS. Dual spatial data layers have been generated in GIS for two different dates representing the pre-cyclone and post-cyclone time sequences utilizing appropriate high spatial resolution satellite images. Finally, a geospatial image-based combinational technique has been utilized employing high temporal and moderate spatial resolution time series satellite data with low temporal and high spatial resolution satellite data. Such an operation results in an improved spatial and temporal resolution of output products enabling capture of dynamics of surface features in the spatiotemporal domain providing more precision and details in the output. This study has been supplemented with necessary Ground Position System (GPS)-based ground truthing, selected field data collection and field-based group discussions outcomes.

Research on Improved Fault Current Analysis Method for Flexible Direct Current Power Grid Considering Alternating Current Feed

Flexible direct current (DC) grid can realize large-scale renewable energy, wide-area coordinated complementation, and reliable power transmission. It is an important development that can be used to support high-voltage and large-capacity flexible DC transmission in the future. The short-circuit current of the DC line is one of the important bases for the selection of key main equipment parameters such as converter valves, DC circuit breakers, and reactors in the flexible DC grid. In this paper, a flexible DC grid equivalent circuit network model with alternating current (AC) feed-in is established. Aiming at the monopolar ground fault of the flexible DC grid grounded through the metal loop, an optimized traditional matrix calculation method is proposed to obtain the accurate line fault current value. On this basis, with an actual engineering background, the equivalent circuit model of the four-terminal bipolar flexible DC power grid is established, and the influence of grounding position, grounding parameters, and current-limiting reactor on the fault current of the DC line is analyzed. Finally, simulation using the PSCAD software verifies the effectiveness and accuracy of the proposed method. The method proposed in this paper can provide the necessary bases and references for the selection of flexible DC grid equipment.

Review of U.S. subsidence monitoring using conventional and satellite based methods

Tracking of surface deformations is typically achieved using periodic measurements of both vertical and horizontal deformations using conventional, Ground Positioning Satellite (GPS), and or photographic techniques. Within the last decade, satellite based methods have also found limited applications over some underground coal mines and commercial applications for open pit mines. In this paper, the authors will review the subsidence monitoring over one of the Colorado operations utilizing precise GPS measurements. This case study will address geologic setting, vertical and horizontal displacements, the influence of topography and gate pillar designs on surface subsidence and fracturing, upon longwall extraction of the Upper D Seam. In addition, we will review the potential use of satellite based, remote sensing methods. InSAR technologies are finding new interest in the U.S. mining industry for (1) investigating the utility of InSAR in discriminating different types of seismic events including underground explosions, natural earthquakes and mine collapses (2) tracking surface subsidence for satisfying permitting requirements and (3) potential use in the area of mine safety. The combination of satellite InSAR imaging and GPS measurements is suggested for enhancing the quality of ground movement analysis including assessment of horizontal deformations and effects on surface resources. Satellite data availability, and the improvements in interpretation and processing tools, are very promising.

Analysis of Hybrid Meander Structures with Additional Shields

Models of hybrid meander structures with additional shields are presented in this paper. The influence of additional shields and their grounding positions on the electromagnetic characteristics of the hybrid meander structures was investigated. Three-dimensional models were created and analyzed using the method of moments (MoM) in the Sonnet® and finite-difference time-domain (FDTD) method in CST Microwave Studio® commercial software packages. The computer-based modeling was verified by physical experiment. The analysis showed that it is possible to control the delay time characteristic using different values of lumped inductive elements without the need to change the overall size of the hybrid meander structure. The delay time varied by 1.2 ns in the range of 1.3 ns to 2.5 ns when the inductivity changed from 1 nH to 10 nH in our investigation. On the other hand, the passband decreased from 2.384 GHz to 0.508 GHz. The additional shields and their grounding positions allowed for increasing the passband by up to 1.6%.

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Optical link stabilization by controlling focus of received beam in mini-unmanned aerial vehicle-to-ground free-space optical communications

To stabilize an optical link, in this study, we propose to control the focus of the received laser beam in free-space optical (FSO) communications between mini-unmanned aerial vehicles (UAVs) and ground stations. Numerical calculations confirm that the coupling efficiency of the received laser beam to an optical fiber (OF) at the ground station is improved by compensating for the shift in the received beam’s focal position caused by the movement of the mini-UAV. Additionally, we conduct an outdoor experiment in which a laser beam is transmitted between two ground positions under the influence of atmospheric turbulence. This experiment indicates the feasibility of controlling the focus of the received beam in realistic environments. These results are expected to significantly contribute to the stabilization of optical links in mini-UAV-to-ground FSO communications.

Research on moon surface positioning and navigation method based on stellar vector measurement

In response to the needs of positioning and navigation in lunar exploration projects such as manned landing on the moon, and the initial positioning of the lunar lander, this paper proposes a lunar positioning and navigation method based on stellar vector measurement and inclination information fusion, and demonstrates the correctness of the algorithm. A semi-physical simulation platform was built and the experimental method verified that the accuracy reached the positioning accuracy index of 30 arc seconds. Lunar surface positioning is different from ground positioning and cannot be positioned by satellites. This method solves the problems of low timeliness and low accuracy of ground measurement and control methods, greatly improving the timeliness and accuracy of lunar surface positioning, and has positive significance for lunar exploration projects.

An attempt of digitalization Bali Strait purse seine capture fisheries data

Similar situations with most small-scale fisheries globally, data collection remains the most highlighted issues in Bali sardine purse seine fishery. Nowadays, one of the promising approaches in fisheries data monitoring is through a technological application. This study attempts to conduct the digitalization of capture fisheries data through a tablet application development and implementation, namely MICT-L. It develops since June 2018 based on an existing paper recorder system and operated by the fishing-port officer. MICT-L was fully established in November 2018 in Muncar and September 2019 in Pengambengan fishing port, and this system has been collected and store digital landing data successfully. In addition to the initiation, a GPS-trackers system, namely TREKFISH, was installed in November 2019 and successfully collected fishing ground position data from 19 vessels until February 2020. During the study, a total of 8,248 landings in Muncar and 6,598 landings in Pengambengan were collected and stored accordingly. MICT-L and TREKFISH data successfully support the faster near real-time statistical analysis and spatial grid productivity. These two initiations are potent tools for collecting and visualizing digital catch data and fishing grounds for Bali purse seine fisheries.

The Nexus of Currency Fluctuations on Imports and Exports of Pakistan

Imports and exports are fulfilling the economic requirements and therefore in both productive ways it is highly demanding and efforts oriented to focus on the proper and effective ways of tackling these factors. Its representing that how Pakistani rupees value effects official debt, imports and exports an also study how it effects stock exchange/market. This research is supportive to examine the fluctuating factors and its role importantly for the development of drawing a clear and supportive economically benefiting policy for the wealth and progression in the fiscal and economic years. This research study was conducted to examine the impacts of currency fluctuations during the time period 2000 to 2010 (11 years) and these years have proved with some interested findings which are compatible with ground realities and positions and facts. The research study found that Pakistan’s exports have significantly increased with the increasing devaluation or declining the monitory value of the Pakistan’s currency. In addition it is also found explicitly the impact of currency fluctuation is positive and considerable on the exports in Pakistan during the time period 2000 to 2010 (11 years) while the impact on currency fluctuations on import is explicitly and implicitly found non related and insignificant. Therefore these findings are proving that imports are not related and found insignificant in relation with currency while the roles with exports are found quite supportive and recognizable. In this time series data OLS model in form of single linear regression has been applied to examine the influential impacts and recognizable factors for the research objectives.

Experimental assessment of the relationship between rainfall intensity and sinkholes caused by damaged sewer pipes

Abstract. In several countries, the rising occurrence of sinkholes has led to severe social and economic damage. Based on the mechanism of sinkhole development, researchers have investigated the correlation between rainfall intensity and sinkholes caused by damaged sewer pipes. In this study, the effect of rainfall intensity on the formation of eroded zones, as well as the occurrence of sinkholes caused by soil erosion due to groundwater infiltration through pipe defects, has been analyzed through model tests. The ground materials in Seoul were represented by weathered granite soil, which is generally used for backfill sewer pipes, and groundwater levels corresponding to three different rainfall intensity conditions were considered. The ground level changes and ground displacements were measured continuously, and the particle image velocimetry (PIV) algorithm was applied to measure the displacement at each position of the model ground. The results indicate that impeding the excessive rise in groundwater levels by securing sufficient sewage treatment facilities can effectively prevent the development of sinkholes caused by pipe defects.

Upper Limb Strikes Reactive Forces in Mix Martial Art Athletes during Ground and Pound Tactics.

Athletes of mixed martial arts use a ground and pound strategy with the strikes in the dominant ground position. The aim of this study was to compare the average peak force (Fpeak) among three punches and to estimate the probability of achieving a skull bone fracture force of 5.1 kN for each type of strike in male and female athletes. A total of 60 males and 31 females (26 ± 8 years, 75 ± 20 kg, 177 ± 11 cm) practicing professional self-defense at the advanced and professional levels performed 15 strikes on a force plate. The analyses of 1360 trials showed significant differences among the strikes Fpeak in females (p < 0.01) and males (p < 0.01). Straight punches had lower Fpeak than palm strikes and elbow strikes in both genders, and palm strikes had higher Fpeak than elbow strikes in females. No difference was observed between palm strikes and elbow strikes in males (p = 0.09). The ground and pound strikes resulted in higher impacts than previously reported strikes in the standing position. Male athletes can deliver a Fpeak above 5.1 kN with a probability of 36% with elbow and palm strikes. Such forces can cause head injury; therefore, the use of these strikes in competition should be carefully considered.

Automated estimation of forest height and underlying topography over a Brazilian tropical forest with single-baseline single-polarization TanDEM-X SAR interferometry

Forest height is an important variable for modeling terrestrial carbon storage and global carbon cycle dynamics. Spaceborne SAR Interferometry (InSAR) has the sensitivity to measure canopy height and the underlying topography. In this paper, we refine and automate an interferometric ground finding approach that exploits few-look (2- to 4-look) averaged interferograms and incorporates the use of a coherent electromagnetic simulator and field inventory data. Using the coherent electromagnetic simulator, an InSAR simulation based on field data is performed to study the true ground position as a function of the statistics of few-look InSAR phase heights from a model perspective. With this statistical model, both the underlying topography and the canopy height (mean and top canopy height) can be estimated. Using German Aerospace Center's (DLR) single-baseline single-polarization TanDEM-X InSAR data, we validate the approach over a Brazilian tropical forest (Tapajós National Forest) with both field inventory and lidar data. As validated against lidar data, the underlying topography is estimated to an accuracy of 3 m. At one hectare aggregated pixel size, InSAR phase-center height is best compared with the field/lidar mean canopy height with an accuracy of 2–3 m, while InSAR-inverted total height best characterizes the lidar top canopy height with an accuracy of 4–5 m. Given the global data availability of TanDEM-X and the future TanDEM-L, this approach has the potential for wall-to-wall mapping of forest height as well as underlying topography and also serves as a complementary tool to other existing InSAR, Polarimetric InSAR (PolInSAR) and SAR tomography (TomoSAR) methods when only single polarization and/or baseline data are available.

Skipjack Tuna Fishing Ground Based on Oceanography Satellite Image Data in Fisheries Management Area (FMA) 713

This study aimed to map the oceanographic conditions and, based on that, to determine the favorable condition of skipjack tuna fishing ground in Fisheries Management Area (FMA) 713. This condition includes sea surface temperature (SST) and chlorophyll-a concentration. The primary data, such as fishing ground position and fish catch per trip, was collected by following the fishing operations that utilized pole and line (in Bone Gulf and Flores Sea) and purse seine fishing operations (in Makassar Strait). The secondary data, such as SST and chlorophyll-a, was derived from oceanographic satellite image data. The result showed that from January to August 2019, the skipjack tuna tends to occupy off shore areas where the sea surface temperature is between 29 - 29.5 oC and the chlorophyll-a density is between 0.10 to 0.15 mg.m3.