No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Direct and Inverse Solutions of Geodesics on the Ellipsoid with Application of Nested Equations
Abstract
This paper gives compact formulae for the direct and inverse solutions of geodesics of any length. Existing formulae have been recast for efficient programming to conserve space and reduce execution time. The main feature of the new formulae is the use of nested equations for elliptic terms. Both solutions are iterative.
... To determine the back azimuth residuals (i.e., the absolute difference between the observed and the predicted back azimuths), a Python code was developed to calculate the predicted back azimuth at each station. This approach uses the station's geographic coordinates and the bolide's peak brightness location (as reported by CNEOS), employing standard great circle bearing formula (Sinnott, 1984;Vincenty, 1975) to provide a robust comparison between observed and theoretical arrival directions (also see Silber (2024a)). The geopy Python library provides convenient functions (e.g., geopy.distance.geodesic ...
... For further details on the mathematical background, see Sinnott (1984) and Vincenty (1975). ...
... To capture a broad range of realistic scenarios, 200 seed points were randomly generated worldwide using a custom Python script (employing libraries such as NumPy and the random module). Each seed location is defined by a latitude (ϕ) and longitude ( Distances and azimuths between the station and each endpoint were calculated via standard geodesy formulae (Sinnott, 1984;Vincenty, 1975) (Eqs. (1-2)). ...
Infrasound sensing offers critical capabilities for detecting and geolocating bolide events globally. However, the observed back azimuths, directions from which infrasound signals arrive at stations, often differ from the theoretical expectations based on the bolide's peak brightness location. For objects with shallow entry angles, which traverse longer atmospheric paths, acoustic energy may be emitted from multiple points along the trajectory, leading to substantial variability in back azimuth residuals. This study investigates how the entry angle of energetic bolides affects the back azimuth deviations, independent of extrinsic factors such as atmospheric propagation, station noise, and signal processing methodologies. A theoretical framework, the Bolide Infrasound Back-Azimuth EXplorer Model (BIBEX-M), was developed to compute predicted back azimuths solely from geometric considerations. The model quantifies how these residuals vary as a function of source-to-receiver distance, revealing that bolides entering at shallow angles of 15 degrees can experience average residuals of 12.4 degrees, with deviations reaching up to 155 degrees at distances below 1500 km, and remaining significant even at 10,000 km. In contrast, bolides with steeper entry angles (greater than 60 degrees) show much smaller deviations, typically under 10 degrees at 1000 km and diminishing to less than two degrees beyond 5000 km. These findings attest to the need for careful interpretation when evaluating signal detections and estimating bolide locations. This work is not only pertinent to bolides but also to other high-energy, extended-duration atmospheric phenomena such as space debris and reentry events, where similar geometric considerations can influence infrasound arrival directions.
... Бессель вперше розробив процедуру розв'язання геодезичної задачі для еліпсоїда обертання з використанням рядів, а для спрощення аналізу результатів обчислень ним було наведено відповідні таблиці. Спираючись на результати зазначених робіт, Вінценті [8,9] розробив відповідні алгоритми для розв'язання геодезичних задач, придатних для перших програмованих настільних калькуляторів. Наведено компактні формули для прямих і обернених розв'язків геодезичних будьякої довжини. ...
... Процедуру виводу цих рівнянь можна назвати методом Бесселя, який Інформатика, обчислювальна техніка та автоматизація Рис. 1. До пошуку геодезичних на трансцендентній поверхні вперше був оприлюднений в його оригінальній статті [5]. Отримані в роботі [19] рівняння мають дещо іншу форму, ніж представлені Бесселем, але вони ведуть безпосередньо до рівнянь, представлених Рейнсфордом [16] і Вінценті [8,9], та в подальшому до створення методу, подібного до наведеного в роботі Рапа [10]. Розуміння методів, представлених в [19], зокрема обчислення еліптичних інтегралів шляхом розкладання в ряд, дає досліднику уявлення про інші геодезичні розрахунки. ...
... When determining the length of the geodesic on the ellipsoid, it is important to mention the associated direct and inverse problems associated to geodesics [6,14,15]: ...
... For the purposes of this work the inverse problem is considered to estimate the geodesic distance ( ) between geographic locations. Particularly, the iterative method of Vincenty [15] was implemented due to its computational flexibility [6]. ...
One of the main problems faced by organizations is the strategic location of its facilities. This is because resource acquisition and operational performance of the supply chain depends on this aspect. Complexity is increased if the most suitable location is not available due to zone restrictions. While facility location models have been developed to solve this problem, only a single zone restriction has been studied. The present work contributes on this context by (a) proposing a solving method for the multi-facility location problem with multi-zone restrictions, (b) considering the ellipsoidal surface of the Earth to provide more accurate estimates of distances, and (c) developing a large instance with real geographic location data for validation of the method and benchmark studies. The results reported in this work corroborate the suitability of the method and that, even with multi-zone restrictions, minimum distance/costs can be achieved when compared to the non-restricted problem.
... Gaussian distribution was used for the variable departure date and Gamma distribution was used for the variable stopover duration. We defined migration distance as the distance between the point of departure from the breeding site and point of arrival at the wintering site and calculated the great circle distance using Vincenty's formulae in the R package geosphere (Vincenty 1975;Hijmans 2022). We tested if migration distance or stopover duration was correlated with number of stopovers using Spearman's rank correlation. ...
Stopovers during migration periods are essential to allow birds to accumulate energy, recover, and/or avoid adverse weather conditions. Recoveries of ringed birds have shown that Pied Avocets (Recurvirostra avosetta) may winter at various places along the East Atlantic Flyway (EAF); however, the connectivity of different stopover sites remains poorly understood. The present study aimed to investigate the spatial and temporal stopover patterns of Pied Avocets and clarify how different wetland areas along the EAF are connected for staging Avocets. We caught 19 adult Avocets at their breeding colonies in the German Wadden Sea using walk-in-traps and tagged them with GPS data loggers (weight 9 g). The Wadden Sea areas of Schleswig-Holstein, Lower Saxony, and the Netherlands were frequently used as stopover sites. Most stopover sites were located at coastal wetlands, with only a few at inland wetlands. On average, the tagged Pied Avocets made 9.1 ± 5.1 stopovers during autumn migration and spent a total of 123.0 ± 45.2 days at stopover sites, with an average stopover duration of 13.4 ± 23.8 days per stopover. Pied Avocets spend more time at stopover sites during migration than many other waders, highlighting the critical importance of high-quality stopover sites for their annual cycle. Muddy estuarine areas in the Wadden Sea (Elbe, Jade-Weser, Ems-Dollart) play an important role during the early migration stages, and should thus be a specific focus for future monitoring actions.
... These variations in distance and height influenced the direction of arrival of the signal, resulting in changes in the azimuth and elevation angles. The calculation of the azimuth angle is based on Vincenty's formulae [30], a widely adopted geodetic method for computing the distance between two points in an ellipsoidal Earth model by leveraging their geographic coordinates (latitude and longitude). After determining the horizontal distance between the UAV's hovering position and takeoff point, the true azimuth angle of the hovering location is derived by calculating the angle between the geodesic line connecting these two points and the reference direction of east (defined as 0 • , with the angles increasing counterclockwise). ...
To address the growing security risks posed by unauthorized unmanned aerial vehicle (UAV) activities, this paper proposes a real-time two-dimensional direction-finding (DF) system for UAVs based on radio frequency (RF) signals. This system employs a six-element uniform circular array (UCA), synchronized HackRF One receivers, and a hybrid algorithm integrating the multiple signal classification (MUSIC) method with a novel weighted average algorithm (WAA). By optimizing the MUSIC spectrum search process, the WAA reduces the computational complexity by over 99.9% at a resolution of 0.1° (from 3,240,000 to 1200 spectral function calculations), enabling real-time estimation of the azimuth and elevation angles. The experimental results demonstrate an average azimuth error of 7.0° and elevation error of 7.7° for UAV hovering distances of 30–200 m and heights of 20–90 m. Real-time flight tracking further validates the system’s dynamic monitoring capabilities. The hardware platform, featuring omnidirectional coverage (0–360° azimuth, 0–90° elevation) and dual-band operation (2.4 GHz/5.8 GHz), offers scalability and cost-effectiveness for low-altitude security applications. Despite limitations in the elevation sensitivity due to the UCA’s geometry, this work establishes a practical foundation for UAV monitoring, emphasizing computational efficiency, real-time performance, and adaptability to dynamic environments.
... The distance between points A and B on the GRS80 ellipsoid is calculated by solving the second geodesic problem [27]. From the numerous solutions to this problem (e.g., ref. [28][29][30]), we used the sphere transition solution method, e.g., the method presented in [31], Section 3.3.4.-Solving the second geodesic problem. ...
Featured Application
A method for improving geodetic networks for the precise layout of high-cost, large-scale structures such as high-speed railway lines.
Abstract
Long linear constructions, particularly high-speed railway lines, place very high demands on the accuracy of the fundamental geodetic controls on which they are based. In general, national reference coordinate systems possess deformations (relative inconsistencies) due to historical factors—primarily the low accuracy of the measurement methods that were used at the time of their development. The reference coordinate system S-JTSK used in the Czech Republic comprises local deformations that are determined using a modern space geodesy method—the Global Navigation Satellite Systems (GNSS). An analysis of the local deformations revealed that, in the Czech Republic, 99% of the length corrections from the coordinate system deformations are in the interval of −1.4 to +1.4 cm/km with a standard deviation of up to 1.4 cm/km. The extreme value in this regard is the length correction from the deformation of +2.5 cm/km and the standard deviation of 3.6 cm/km. These values exceed the required accuracy of 1 cm/km, and the length corrections from the deformations, together with the length corrections from the used projection, must be taken into account when undertaking surveying work on high-speed railway lines in the Czech Republic (also with the height correction for lengths). The magnitude of the scatter also indicates the distortion of the S-JTSK projection conformality due to the deformations.
... The static sessions enabled the calculation of the geodetic coordinates (ϕ, λ, h) for S and P, yielding a geodetic azimuth α = 334 • 59 ′ 13.1 ′′ and a distance D = 983.861 m, calculated using Vincenty's formulas [25]. The corresponding astronomical azimuth was then derived using the Laplace equation: ...
It is not widely recognized today that astronomical methods for azimuth determination continue to rank among the most accurate techniques for establishing orientation. However, their importance has diminished with the rise of GNSS techniques, which do not require clear skies and work in various weather conditions. Unlike GNSSs, astronomical methods rely on clear visibility and involve calculations based on spherical trigonometry. This work aims to simplify these calculations by providing open-source Python scripts that automate the process. These scripts also simulate the achievable precision, allowing users to plan optimal observations in advance. One of the aims of this work is to demonstrate that, in certain cases, the integration of ‘contemporary’ tools with techniques now regarded as ‘outdated’ can produce very accurate results. Beyond their purely historical significance, which has profoundly influenced modern surveying methods, the integration of astronomical measurements with modern computing codes allows surveyors to achieve azimuths with an accuracy of ±1–2 arcseconds.
... Vincenty's formula is better than the method of great-circle distance as it considers the earth as an oblate spheroid, which increases accuracy. Vincenty's formula for computing the shortest distance between two coordinate points on Earth is applied in the thesis [25]. ArcGIS software has an in-built capability of using the Vincenty formula for measuring the distance between any two coordinate points on a map, which is utilized to measure the track lengths and direct distance between cyclogenesis and cyclolysis locations on the map. ...
The Pacific Subtropical High (PSH) predominantly develops during the boreal summer (June–August) over the Northwest Pacific (NWP) basin, with August accounting for the highest tropical storm (TS) frequency (46.9%). This study examines the critical influence of the PSH’s position on TS trajectories and the consequent exposure of affected countries, utilizing four decades (1977–2016) of August TS data from the NWP. A total of 55 TSs, unaffected by other environmental factors, were analyzed. The PSH’s observed position during each TS’s turning point was delineated using a geopotential height of 500 hPa, while track sinuosity was quantified using a validated sinuosity index (SI). Three distinct TS paths were identified: an eastward PSH position leads to highly sinuous tracks, directing TSs toward Japan; a westward PSH position results in straighter tracks, steering TSs toward the South China Sea (SCS) below Taiwan; and a mid-position guides TSs toward Taiwan. These findings underscore the PSH’s pivotal role in modulating TS behavior and provide valuable insights for disaster risk management agencies to mitigate TS impacts in the NWP basin, the world’s most active TS region, responsible for one-third of global tropical cyclones.
... The results of the flight route selection were output as coordinates (pixels) on the image, which were converted to latitude and longitude coordinates to issue movement instructions to the drone. The conversion from a planar coordinate system (meters) to latitude and longitude was performed using Vincenty's formulae [15][16][17]. The direct method requires the latitude and longitude of the center of the image as input values and the distance and azimuth from the center of the image to the start and end points of the flight route, respectively. ...
Stable pear cultivation relies on cross-pollination, which typically depends on insects or wind. However, natural pollination is often inconsistent due to environmental factors such as temperature and humidity. To ensure reliable fruit set, artificial pollination methods such as wind-powered pollen sprayers are widely used. While effective, these methods require significant labor and operational costs, highlighting the need for a more efficient alternative. To address this issue, this study aims to develop a fully automated drone-based pollination system that integrates Artificial Intelligence (AI) and Unmanned Aerial Vehicles (UAVs). The system is designed to perform artificial pollination while maintaining conventional pear cultivation practices. Demonstration experiments were conducted to evaluate the system’s effectiveness. Results showed that drone pollination achieved a fruit set rate comparable to conventional methods, confirming its feasibility as a labor-saving alternative. This study establishes a practical drone pollination system that eliminates the need for wind, insects, or human labor. By maintaining traditional cultivation practices while improving efficiency, this technology offers a promising solution for sustainable pear production.
... We introduce a geodesic algorithm based on Vincenty's formulae (Vincenty, 1975) to transform the latitude and longitude coordinates of K. Huang et al. International Journal of Applied Earth Observation and Geoinformation 137 (2025) 104422 a geographic target into global positions on the Earth's surface. ...
... Stadium capacity and geographical coordinates of stadiums were obtained from publicly available data on these venues. Using these coordinates, the distances between teams were calculated based on the formula of Vincenty (1975) for computing geodesic distances on a reference ellipsoid. ...
We study the substitution effect between religious worship and non-religious leisure activity. The Jewish religion strictly forbids work on Shabbat, which is considered a holy day. However, football (soccer) was exempt from the 'religious status quo' agreement on religious-secular relations in Israel, and roughly 25% of games take place during Shabbat. This has led to heated debates, since Shabbat observants cannot attend these games. However, secular fans refer to Shabbat games as a symbol of freedom from religion, also claiming that these games are much more attractive for families with children. Thus, it is an empirical question whether Shabbat games attract more or fewer fans. We used data on 1,629 games in the top tier of Israeli football between the 2012-13 and 2018-19 seasons. After teasing out the effect of selection to obtain unbiased estimates, our empirical analyses find that Shabbat games attract approximately 10% fewer fans. This result suggests that the loss of the observant fans on these games is not fully compensated by the possible gain from secular fans who prefer Shabbat games. Our findings illustrate the importance of religious motives in the budget constraints of time allocation.
... Using individual WGS84 location information, the research's operational definition of return migration is defined as an individual in sub-population M1-M2 whose migration destination in T3 is more than 10 KM in distance from her/his household location at T1. To calculate the distance between two geographic points, the research adopts the method proposed by Vincenty (1975). The underlying reason to dichotomize population M1-M2 into return migrants and onward migrants lies in the fact that return migrants and onward migrants behave and respond to ecological variables (e.g. ...
Research question: Migration studies have confirmed that migrants are associated with higher lifetime gains and social mobility than non-migrants. As hard-to-reach population, although Taiwan indigenous peoples (TIPs) are much more migratory than the ordinary people, it is contradictory to see that poverty and inequality remain persistent and prevalent among TIPs. Data and methodology: The research utilizes record linkage and geocoding methods to build anonymized population dynamics data, based on household register from 2013 to 2018. Using this longitudinally linked data, the research unveils the entangled features of population dynamics in TIPs. With a focus on the effects of income inequality in the context of systemic barriers and structural factors, the research explores migration dynamics in primary, return, and onward migrations in the context of regional inequality. Main research findings: (1) migration of TIPs is characterized by migration between areas of high income-high inequality and areas of low income-low inequality; (2) TIPs are much more migratory in areas of high income-high inequality than in areas of low income-low inequality; inequality in wealthy areas outweighs income in triggering migration, but migration in areas with high poverty and low inequality is triggered by low income gain; (3) repeat migration, particularly the return type, is characterized by a net gain of migrants moving from low poverty but high inequality areas into areas with high poverty but low inequality; (4) Onward migration of TIPs counters existing findings. The main reason why migration is less likely to promote TIPs social mobility is due to weak ethnic and socioeconomic connections and systemic barriers between TIPs and non-TIPs population.
... After excluding CEOs for whom we cannot identify the birth county, we obtain birthplace information for 1,888 out of the 6,543 U.S.-born CEOs in 1,674 nonfinancial, nonutility firms with 12,395 firm-year observations covered by ExecuComp from 1992 to 2018. 4 We classify a CEO as a home CEO if the distance between that person's place of birth and the firm's headquarters is less than 100 miles. 5 Next we follow the procedure of Vincenty (1975) and compute the distance between the CEO's hometown and the firm's headquarters. 6 After merging with financial data from Compustat and removing missing values of firm and CEO characteristics, our sample includes 1,595 unique CEOs in 1,268 firms and 10,692 firm-year observations. ...
We examine the association between CEO birthplace proximity and financial misconduct. We find that CEOs managing firms near their birthplaces (home CEOs) are associated with less financial misconduct compared to other CEOs. This association is not attributable to differences in corporate governance. The relationship strengthens in areas with a strong local investment presence and greater religious commitment as well as among CEOs with longer tenures in their home state. Our findings are robust to addressing potential selection and omitted variable biases as well as to conducting multiple robustness tests, including analyses of involuntary CEO changes and headquarters relocations. We also find a similar association for CFOs, with firms employing home CFOs exhibiting less financial misconduct.
... Moreover, the horizontal and vertical axis represent, respectively, the horizontal and vertical distance from the geodetic coordinates in the DEM grid to the destination airport in nautical miles. This distance was computed by using the Vincenty formulae [41]. ...
We introduce a flight-procedure generation framework that relies on the optimal version of the rapidly-exploring random tree (RRT*) algorithm, where nodes are connected using Dubins paths. This framework is employed for the generation of required navigation performance authorization required approach (RNP AR APCH) procedures, taking into consideration design constraints established by the international civil aviation organization (ICAO). To evaluate the framework’s viability, we examine a series of challenging scenarios, for which we swiftly generate a series of operationally-compliant flight procedures. Furthermore, we assess how several of the RRT* configuration parameters can affect the generated procedures. The automation capabilities provided by our framework will benefit flight-procedure designers, saving time in the design process and enabling them to propose flight procedures which will potentially lead to more efficient aircraft trajectories.
... To calculate this azimuth value, geographic coordinates are required. In the calculation of the Qibla azimuth, ellipsoidal geodetic basic problem solutions are used, as they are more accurate compared to other traditional and spherical solutions [23][24][25] Various methods have been developed for solving geodetic fundamental problems, and the Vincenty method [26] has been used in this study due to its algorithmic clarity, programmability, and applicability for large distances (S > 1000 km) [27]. As alternatives, two other methods [28][29] can also be recommended to users. ...
In Islamic societies, knowing the direction of the Qibla is important in the planning of religious areas. In urban plans designed by practitioners where the Qibla direction is not considered, inconsistencies arise among religious areas. These inconsistencies reduce the project areas within the structures and cause loss of space. To address these inconsistencies, plan revisions are required. However, plan revisions extend the construction periods of projects and increase the projected costs. Adding the Qibla direction as a legend to large-scale maps (LSMs) used as base maps in the drawing of urban plans is an option that can be used to eliminate these inconsistencies. In this study, the Qibla direction for all LSMs in Türkiye's national mapping was calculated with geodetic accuracy to eliminate the mentioned inconsistencies. These calculations and the generated visual outputs are presented to users through the Map Qibla Direction Calculation Interface (MQDCI) developed in the MATLAB environment. When any coordinate data or the name of the relevant LSM is entered as input into the developed interface, the Qibla direction value for that map is provided to the user in this study. The developed interface allows the Qibla direction angle to be calculated and presented to the user with geodetic accuracy and instantly, without the need for measurements and calculations performed in the field. Although the developed interface is designed according to the Kaaba, which is the Qibla for Muslims, and Türkiye's geographical boundaries, it is also suitable for other religions in Türkiye or different religions in other countries. For this, it is sufficient to know the national mapping systems of the countries and the geographical coordinates of the Qibla in Christianity and Judaism.
... The vehicle's true displacement, x b GNSS , is found using Vincenty's formula for geodesics on an ellipsoid [3], based on the vehicle's longitudinal and latitudinal positional information [3,36,37]. The accuracy of x b GNSS is however limited to the accuracy of the GNSS used in this study which, according to [38], is defined as AE3 m. Figure 1 shows the prediction block of the WhONet approach 1 during the absence of the GNSS signal. ...
This paper proposes a transfer learning approach to recalibrate our previously developed Wheel Odometry Neural Network (WhONet) for vehicle positioning in environments where Global Navigation Satellite Systems (GNSS) are unavailable. The WhONet has been shown to possess the capability to learn the uncertainties in the wheel speed measurements needed for correction and accurate positioning of vehicles. These uncertainties may be manifested as tyre pressure changes from driving on muddy and uneven terrains or wheel slips. However, a common cause for concern for data-driven approaches, such as the WhONet model, is usually the inability to generalise the models to a new vehicle. In scenarios where machine learning models are trained in a specific domain but deployed in another domain, the model’s performance degrades. In real-life scenarios, several factors are influential to this degradation, from changes to the dynamics of the vehicle to new pattern distributions of the sensor’s noise, and bias will make the test sensor data vary from training data. Therefore, the challenge is to explore techniques that allow the trained machine learning models to spontaneously adjust to new vehicle domains. As such, we propose the Recalibrated-Wheel Odometry neural Network, based on transfer learning, that adapts the WhONet model from its source domain (a vehicle and environment on which the model is initially trained) to the target domain (a new vehicle on which the trained model is to be deployed). Through a performance evaluation on several GNSS outage scenarios—short-term complex driving scenarios such as on roundabouts, sharp cornering, hard-brake and wet roads (drifts), and on longer-term GNSS outage scenarios of 30s, 60s, 120s and 180s duration—we demonstrate that a model trained in the source domain does not generalise well to a new vehicle in the target domain. However, we show that our new proposed framework improves the generalisation of the WhONet model to new vehicles in the target domains by an average of 32% (i.e. 32% reduction in the vehicle position error estimation across the scenarios investigated).
... These dummy variables are 1 if the respondents were exposed to protests within 25 km, 50 km, and 75 km radius of the respondent's location, and 0 otherwise. We calculate the distance between the respondent and the protest event using Vincenty's (1975) formula. The two surveys provide us with the cities or rural districts of the respondents, from which we derive the coordinates of the centroids. ...
This study examines the effect of the "Woman, Life, Freedom" protests in Iran during the last quarter of 2022 on individual life satisfaction. To assess this impact, we use two original representative surveys conducted before and after the protests in 2022. The repeated cross-sectional dataset was generated using the same sampling approach in both surveys to ensure representativeness. Our results, based on probit regressions and an instrumental variable approach for a sample of 2,256 individuals, show that the violent protest environment had a significant negative effect on life satisfaction in Iran. To measure respondents' exposure to the protests, this study uses various indicators based on the distance of individual respondents from the protest locations. Overall, the protest environment decreased the probability of life satisfaction by 3.6 percentage points. These results remain robust when controlling for other determinants of individual life satisfaction. Moreover, we find significant heterogeneity among respondents based on gender, with the largest negative impact of the protests on life satisfaction observed among women. This negative effect is more pronounced than the impact of unemployment. Another key finding is the heterogeneous effect depending on media consumption, with international TV viewers reporting the largest decrease in life satisfaction. The mechanism underlying these effects was further explored through mediation analysis, which reveals that feelings of insecurity and increased surveillance are key mediators of the total effect.
... Hierarchical clustering was chosen as it does not require any predefined number of clusters and does not allow for any points (households) to be treated as noise [34,35], unlike density-based clustering [36]. A distance matrix between all the households in the district was calculated using the 'Vincenty' (ellipsoid) method [37]. To determine the optimal number of clusters (k), the gap statistic was considered as a goodness of clustering measure [38]. ...
Understanding spatiotemporal distributions and niches of vectors and intermediate hosts for ecologically dependent pathogens is crucial for identifying endemic areas, assessing habitat suitability for transmission, and targeting interventions for both the environment and humans. This study focuses on Biomphalaria sudanica and B. stanleyi, intermediate hosts of intestinal schistosomes, with over 700 million people at risk in endemic areas. We identified how extreme flooding and seasonal changes influence habitat preferences and species interactions across 674 sites in 52 villages in rural Uganda between 2022-2024. A comprehensive analysis of ground truth data was conducted, covering spatiotemporal information, site characteristics, physicochemical parameters, ecological factors, and human activities. Spatiotemporal models incorporating a new polygon-based method to account for space, bypassing limitations of administrative boundaries, with time as a fixed effect were developed to analyse snail abundance. B. sudanica was associated with marshy sites near lake shorelines and presence of hyacinths, while B. stanleyi was more likely found in deeper waters with Vallisneria plants. However, both species often cohabited at the same sites. The extent of habitat suitability for each species fluctuated seasonally and more starkly with extreme flooding resulting in switching of dominance between species. Our study shows that climatic variations may influence local changes in habitat suitability without necessitating an expansion of environmental areas. By providing a robust, generalisable spatiotemporal modelling pipeline, our study enables precise tracking of dynamic ecological niches in a changing climate that, if replicated in other areas, can be used to better target environmental and human interventions.
... We exploit geographic coordinate information (latitudes and longitudes) to calculate geodetic distance estimates to two classes of public amenities in Accra: suburban police stations and hospitals. Drawing on Vincenty (1975), the distance estimation approach takes the length of the shortest curve between two points, using an ellipsoidal model of the earth. The methodology is based on the World Geodetic System 1984 (WGS84) datum, which is the same used by Google Maps,Google Earth,and GPS gadgets. ...
Shared occupancy arrangements are on the rise in recent years due to affordability constraints in homeownership. This article examines for the first time the property tax compliance behavior of shared dwellings, where homeowners rent out part of their own homes to tenants. Using administrative property‐level data from Ghana, where homeowners are responsible for tax payments, we reveal that shared dwellings, compared to pure owner‐occupied homes, are more likely to be in tax arrears. The noncompliance of shared dwellings is more sensitive to property tax hikes than pure owner‐occupied homes, and greatest among those in the least affluent geographic areas. These effects are moderated by reciprocity, in that compliance levels are higher in locations closer to public services and amenities. The findings provide new insights for policymakers on the tax compliance effects arising in shared occupancies.
... To validate our Wi-Fi-based estimation method, we compare the results to ground truth data computed from GPS coordinates (GPS data is only used as a reference point to validate our method's accuracy). For each month, we use Vincenty's formulae [33] to calculate distances between GPS coordinates and cluster them using a threshold of 100m to account for indoor GPS error. The mean absolute error (MAE) is 1.017 and the root mean squared error (RMSE) is 1.761. ...
In recent years, school attendance issues among university students have been increasing, which can lead to repeating courses, dropping out of school, or even social withdrawal. Despite the existence of counseling services, students often delay help-seeking, which can cause symptoms to worsen and make support more difficult. Thus, it is essential to identify at-risk students early and encourage them to seek help. A realistic approach must minimize the burden on students, rely only on devices they already own, and operate correctly even for students who are less engaged or prone to social withdrawal. While several techniques have been proposed to estimate individual indicators, they fail to address one of these requirements due to requiring additional devices or requiring user attention and interaction. In this paper, we propose an unobtrusive screening method for detecting subtle signs of school attendance issues in university students. We develop a smartphone app to collect sensor data and collect ground truth information using questionnaires for (1) sleep problems and (2) decreased student engagement. We collect data from 58 university students for about 10 months, and build estimation models for the above indicators. Our evaluation shows that the estimation models are sufficiently accurate in flagging problematic cases. The indicators can then be used to notify at-risk students and medical practitioners, enabling timely intervention. This screening is not intended to replace traditional face-to-face medical examinations, but rather to selectively flag at-risk students and connect them with medical experts.
... All distances were presented in the form of pairwise comparison matrices. The calculation of geographic distance was based on the Vincenty algorithm, which is used to compute the distance between two points on a great circle using their longitudinal and latitudinal coordinates and accounts for the ellipsoidal shape and irregularities of the Earth [65]. The environmental distance matrix was constructed based on the Euclidean distance metric. ...
Background
The visual similarities observed across various plant groups often conceal underlying genetic distinctions. This occurrence, known as cryptic diversity, underscores the key importance of identifying and understanding cryptic intraspecific evolutionary lineages in evolutionary ecology and conservation biology.
Results
In this study, we conducted transcriptome analysis of 81 individuals from 18 natural populations of a northern lineage of Picea brachytyla sensu stricto that is endemic to the Qinghai-Tibet Plateau. Our analysis revealed the presence of two distinct local lineages, emerging approximately 444.8 thousand years ago (kya), within this endangered species. The divergence event aligns well with the geographic and climatic oscillations that occurred across the distributional range during the Mid-Pleistocene epoch. Additionally, we identified numerous environmentally correlated gene variants, as well as many other genes showing signals of positive selection across the genome. These factors likely contributed to the persistence and adaptation of the two distinct local lineages.
Conclusions
Our findings shed light on the highly dynamic evolutionary processes underlying the remarkably similar phenotypes of the two lineages of this endangered species. Importantly, these results enhance our understanding of the evolutionary past for this and for other endangered species with similar histories, and also provide guidance for the development of conservation plans.
... We utilize the Vincenty's formula (Vincenty, 1975) for calculating the geographical distance between two succeeding GPS points P 1 and P 2 . Denoting the time difference between P 1 and P 2 as Δt, the first three motion features of P 1 are then calculated based on the following equations: ...
Identifying the distribution of users' transportation modes is an essential part of travel demand analysis and transportation planning. With the advent of ubiquitous GPS-enabled devices (e.g., a smartphone), a cost-effective approach for inferring commuters' mobility mode(s) is to leverage their GPS trajectories. A majority of studies have proposed mode inference models based on hand-crafted features and traditional machine learning algorithms. However, manual features engender some major drawbacks including vulnerability to traffic and environmental conditions as well as possessing human's bias in creating efficient features. One way to overcome these issues is by utilizing Convolutional Neural Network (CNN) schemes that are capable of automatically driving high-level features from the raw input. Accordingly, in this paper, we take advantage of CNN architectures so as to predict travel modes based on only raw GPS trajectories, where the modes are labeled as walk, bike, bus, driving, and train. Our key contribution is designing the layout of the CNN's input layer in such a way that not only is adaptable with the CNN schemes but represents fundamental motion characteristics of a moving object including speed, acceleration, jerk, and bearing rate. Furthermore, we ameliorate the quality of GPS logs through several data preprocessing steps. Using the clean input layer, a variety of CNN configurations are evaluated to achieve the best CNN architecture. The highest accuracy of 84.8% has been achieved through the ensemble of the best CNN configuration. In this research, we contrast our methodology with traditional machine learning algorithms as well as the seminal and most related studies to demonstrate the superiority of our framework.
... This is done by computing the average path of a route (using previous legitimate flight records) and extract four major geolocation points for each source and destination (illustrated in Figure 2). Afterwards, we measure the distance between each point in the route (latitude, longitude, as received by the messages) and the aforementioned major points (see Figure 2) using the inverse method of Vincenty's distance formulae [17]. ...
Although the ADS-B system is going to play a major role in the safe navigation of airplanes and air traffic control (ATC) management, it is also well known for its lack of security mechanisms. Previous research has proposed various methods for improving the security of the ADS-B system and mitigating associated risks. However, these solutions typically require the use of additional participating nodes (or sensors) (e.g., to verify the location of the airplane by analyzing the physical signal) or modification of the current protocol architecture (e.g., adding encryption or authentication mechanisms.) Due to the regulation process regarding avionic systems and the fact that the ADS-B system is already deployed in most airplanes, applying such modifications to the current protocol at this stage is impractical. In this paper we propose an alternative security solution for detecting anomalous ADS-B messages aimed at the detection of spoofed or manipulated ADS- B messages sent by an attacker or compromised airplane. The proposed approach utilizes an LSTM encoder-decoder algorithm for modeling flight routes by analyzing sequences of legitimate ADS-B messages. Using these models, aircraft can autonomously evaluate received ADS-B messages and identify deviations from the legitimate flight path (i.e., anomalies). We examined our approach on six different flight route datasets to which we injected different types of anomalies. Using our approach we were able to detect all of the injected attacks with an average false alarm rate of 4.3% for all of datasets.
... The adoption of this feature is motivated by the fact that such antennas do not have an omnidirectional pattern on the elevation plane, so that an angular deviation different from zero may have a significant impact on propagation losses. The second group of features depends not only on the positions of the transmitter and the receiver, but also on the positions and geometry of the buildings preventing line of sight (LOS) 9 In practice, the Vincenty's inverse method [28] is used to compute the geographical distance d propagation, as illustrated in Fig. 4; in particular, these features aim at capturing some relevant properties of key obstructions. In the following, it is assumed that at the i-th position of the receiver (with i = 1, 2, ..., N ) the view of the transmitter is obstructed by K (i) buildings, whose heights are denoted {h (i) l , l = 1, 2, ..., K (i) } (note that K (i) = 2 in Fig. 4). ...
Recently, the need of deploying new wireless networks for smart gas metering has raised the problem of radio planning in the169 MHz band. Unluckily, software tools commonly adopted for radio planning in cellular communication systems cannot be employed to solve this problem because of the substantially lower transmission frequencies characterizing this application. In this manuscript a novel data-centric solution, based on the use of support vector machine techniques for classification and regression, is proposed. Our method requires the availability of a limited set of received signal strength measurements and the knowledge of a three-dimensional map of the propagation environment of interest, and generates both an estimate of the coverage area and a prediction of the field strength within it. Numerical results referring to different Italian villages and cities evidence that our method is able to achieve good accuracy at the price of an acceptable computational cost and of a limited effort for the acquisition of measurements in the considered environments.
... This indicator is very useful where the user is mobile and frequently updates their location profile. [15] uses Vincenty's geometric median an estimate well applied to the field of Geography and land surveying [25] to estimate the location of a Twitter user using their last 5 geotagged tweets that occurred within a 15km radius, as shown in (1). ...
The increasing popularity of the social networking service, Twitter, has made it more involved in day-to-day communications, strengthening social relationships and information dissemination. Conversations on Twitter are now being explored as indicators within early warning systems to alert of imminent natural disasters such earthquakes and aid prompt emergency responses to crime. Producers are privileged to have limitless access to market perception from consumer comments on social media and microblogs. Targeted advertising can be made more effective based on user profile information such as demography, interests and location. While these applications have proven beneficial, the ability to effectively infer the location of Twitter users has even more immense value. However, accurately identifying where a message originated from or author's location remains a challenge thus essentially driving research in that regard. In this paper, we survey a range of techniques applied to infer the location of Twitter users from inception to state-of-the-art. We find significant improvements over time in the granularity levels and better accuracy with results driven by refinements to algorithms and inclusion of more spatial features.
... For NDBC data, the time and spatial collocation standard is 0.5 h and 10 km respectively. Here the spatial difference was calculated using the latitude and longitude of two locations by the Vincent's formula (Vincenty, 1975). Moreover, the scatterometer data are not suitable for observation near to the coast. ...
This study analyzes the effects of noise equivalent sigma zero (NESZ) on wind retrieval accuracy based on the estimated NESZ and wind retrievals from Gaofen-3 (GF3) synthetic aperture radar (SAR) wave mode data. The NESZ was estimated from the normalized radar cross-section (NRCS) bottom envelope from the calm sea (winds <1 m/s). The data used included GF3 SAR wave mode data, collocated NOAA/NCEP Global Forecast System (GFS), Advanced Scatterometer (ASCAT) and National Data Buoy Center (NDBC) buoy wind data. First, the GF3 data were recalibrated using a numerical weather prediction method in which the recalibration coefficients at four polarizations and different incidence angles were estimated. The NESZ trends were then estimated along with the in-orbit time and incidence angles based on the recalibrated GF3 NRCS. NESZ trends show no obvious change with in-orbit time, whereas it shows significant fluctuations with the incidence angle. Moreover, wind speed and direction were retrieved by the CMOD5.N model using the optimal scheme (for co-polarized data, VV, and HH data) and a linear model (for cross-polarized data, VH, and HV data). The wind retrieval accuracy was estimated by comparison with ASCAT and NDBC winds. Finally, the wind retrieval accuracy with the NESZ for different incidence angle bins was analyzed. The root mean square error (RMSE) of the wind speed and direction increase with the NESZ for each polarization. For the NESZ effects, the co-polarized data are more evident than the cross-polarized data for wind speed retrieval, whereas the two co-polarized data are close for wind direction retrieval. When the NESZ increases from −41 dB to −29 dB, there is a wind speed RMSE degradation of 1.5 m/s, 1.2 m/s, 0.7 m/s and 0.5 m/s for VV-, HH-, VH-, and HV-polarized data respectively, while there is a wind direction RMSE degradation of 5o for co-polarized data. This reveals the necessity of reducing the SAR NESZ to improve wind retrieval accuracy.
Epigenetic adaptations around conception can help organisms adjust to their future environment. Pre-conception cold exposure is thought to increase active brown fat mass, and as brown fat metabolizes stored energy to generate heat, this helps adjust to life in cold environments. We examine the implications of this process for human metabolic health. We use data on 430,000 individuals born between 1934 and 1971 from the UK Biobank, and match these to historical temperature data. To isolate causal impacts of temperature, we utilize day-specific temperature deviations during the calculated pre-conception period relative to the long-term mean temperature for the same location and day of year. This approach leverages a quasi-random variation in temperature. We find that individuals conceived when temperatures were lower than usual have lower body mass indices (BMI), smaller waist circumferences, and lower levels of triglycerides and total cholesterol in adulthood, while there was no evidence for an effect on glycated hemoglobin (HbA1c). These findings have implications for potential health effects of climate change, and more strongly, for effects of improved indoor insulation.
Geological hydrogen is emerging as a promising clean energy resource, but finding commercial quantities is challenging due to complex hydrogen production, migration, and accumulation dynamics in the subsurface. This study applies Monte Carlo simulation and an XGBoost regression model to assess the influence of various formations, geologic provinces, tectonic plate types, and boundary conditions on hydrogen concentrations. Key predictors identified include formation type, geological province, and proximity to province boundaries, respectively, highlighting the role of spatial relationships in hydrogen retention and potential lateral migration.
Monte Carlo simulations indicate that ophiolites, orogenic belts, and passive margins hold the highest hydrogen potential, particularly within ≈133 km of certain geological province boundaries. These regions provide favorable geological settings due to active fault preservation, ultramafic rock serpentinization, and sedimentary basin storage, which enhance hydrogen generation, migration, and trapping. In contrast, cratons and magmatic provinces exhibit minimal retention, primarily due to their stable geological history, lack of reactive lithologies, and limited faulting, which restricts both hydrogen generation and trapping.
Tectonic influences further shape hydrogen distribution, with rigid plates and convergent boundaries emerging as prime exploration targets due to their association with faulting, subduction-related fluid migration, and structural traps that facilitate hydrogen retention. Transform boundaries show moderate potential, as fault movement can create migration pathways but may also enhance leakage. In contrast, divergent boundaries exhibit the lowest retention capacity, as continuous extensional activity and high permeability allow hydrogen to escape rather than accumulate. These findings provide a data-driven framework for optimizing hydrogen exploration by prioritizing high-prospect zones while refining future investigation strategies. This research supports the development of geological hydrogen as a viable, clean energy resource, contributing to the global energy transition.
This study investigates whether companies strategically address corporate social responsibility (CSR) red flags to minimise their risks during periods of high economic policy uncertainty (EPU). We observe increased investment in social and environmental concerns amid EPU, particularly amongst firms with numerous institutional investors, those in consumer‐oriented sectors, and those with irreversible investments. Addressing CSR issues can enhance firms' trade credit and employee loyalty. Additionally, such investments can reduce firms' performance volatility in the face of elevated EPU. During periods of high EPU, firms actively reallocate resources to CSR while scaling back other investment activities, thereby demonstrating varying industry‐specific CSR priorities and emphasising a proactive risk management approach.
Tor users derive anonymity in part from the size of the Tor user base, but Tor struggles to attract and support more users due to performance limitations. Previous works have proposed modifications to Tor’s path selection algorithm to enhance both performance and security, but many proposals have unintended consequences due to incorporating information related to client location. We instead propose selecting paths using a global view of the network, independent of client location, and we propose doing so with a machine learning classifier to predict the performance of a given path before building a circuit. We show through a variety of simulated and live experimental settings, across different time periods, that this approach can significantly improve performance compared to Tor’s default path selection algorithm and two previously proposed approaches. In addition to evaluating the security of our approach with traditional metrics, we propose a novel anonymity metric that captures information leakage resulting from location-aware path selection, and we show that our path selection approach leaks no more information than the default path selection algorithm.
One of the episodes of the ASIAEX 2001 experiment (in the South China Sea) is considered, in which a large internal wave soliton moved along two stationary acoustic paths 32 and 19 km long, and associated fluctuations in the intensity of low-frequency sound (224 and 300 Hz) were observed. During the study, the phenomenon of constancy of the dominant frequency of fluctuations over time was discovered. For example, during 6-h soliton motion along a long path, where the sea depth changed three times (from 350 to 120 m), and the soliton velocity, two times (from 2 to 1 m/s), the dominant frequency of fluctuations remained approximately constant at 1.5 cph (cycles per hour) with an accuracy of 10%. The paper analyzes the causes of this phenomenon. For this, the soliton is considered within the framework of a two-layer model of the aquatic environment, and sound propagation, within the framework of mode and ray theories. According to ray theory, the dominant frequency of fluctuations is determined by the ratio of the soliton velocity to the ray cycle responsible for the dominant fluctuations. In mode theory, a similar expression is obtained where the role of the ray cycle is played by a combination of spatial beat periods of several pairs of modes. It is shown that with a change in the sea depth, the soliton velocity and the ray cycle change almost proportionally, as a result of which the dominant frequency of fluctuations remains constant. The described phenomenon may be universal and not limited to the ASIAEX water area. The constancy of the dominant frequency allows one, in particular, to determine the variable soliton velocity as a function of time or distance, which is successfully demonstrated in the work and can be used for acoustic monitoring of solitons.
Determining the direction of the Qibla, which points towards the Kaaba in Mecca, is an essential requirement for Muslims during their daily prayers. With the advent of modern computational techniques, various algorithms have been developed to calculate the Qibla directionaccurately. This paper presents a comparative study of five widely used algorithms: the Haversine formula, Vincenty's formula, the Spherical Trigonometry method, the Great Circle Navigation method, and the Equatorial Oblique Cylindrical Projection method.We provide a detailed explanation of all five algorithms, highlighting their underlying principles, mathematical formulations, and implementation details using python programing language. Additionally, we analyze the accuracy and performance trade-offs between these methods, enabling users to make informed decisions based on their specific requirements. Also, to evaluate the performance of the algorithms, 300 random locations were generated on the map using Python. Keywords: Qibla Direction, Haversine, Vincenty, Spherical Trigonometry, Great Circle Navigation,Equatorial Oblique Cylindrical Projection, Python.
When protoplanetary discs are externally irradiated by far-ultraviolet (FUV) photons from OBA-type stars, they lose material through photoevaporative winds. This reduces the amount of material that is available to form planets. Understanding the link between the environmental irradiation and the observed disc properties requires accurately evaluating the FUV flux at star-hosting discs, which can be challenging because of the uncertainty in stellar parallax. We addressed this issue by proposing a novel approach: using the local density distribution of a star-forming region (i.e. 2D pairwise star separation distribution) and assuming isotropy, we inferred the 3D separation between star-hosting discs and massive stars. We tested this approach on synthetic clusters and showed that it significantly improves accuracy compared to previous methods. We computed the FUV fluxes for numerous star-bearing discs in seven regions within ∼200 pc, six regions in Orion and in Serpens sub-regions. We provided a publicly accessible catalogue. We found that discs in regions hosting late-type B and early-type A stars can reach non-negligible FUV radiation levels for the disc evolution (10-100 mathrm G ). We investigated dust disc masses relative to FUV fluxes and detected indications of a negative correlation when we restricted the investigation to average region ages. However, we emphasize the need for more stellar and disc measurements at > to probe the dependence of disc properties on environmental irradiation. The method presented in this work is a powerful tool that can be expanded to additional regions.
This chapter deals with calculation methods of digital terrain modeling. First, we describe the Evans–Young method, a classic finite-difference technique for computing local topographic attributes. Second, we present two methods to derive models of local morphometric variables from digital elevation models based on plane square grids as well as spheroidal equal angular grids at a sphere and an ellipsoid of revolution. The method for plane square grids uses the approximation of the third-order polynomial to the 5 � 5 moving window by the least squares. The method for spheroidal equal angular grids is based on the approximation of the second-order polynomial to the 3 � 3 moving window by the least squares. We briefly review techniques to compute nonlocal and combined morphometric variables on plane square grids and spheroidal equal angular grids, approaches to detect structural lines including calculation of horizontal deflection, as well as algorithms for derivation of two-field specific morphometric variables and landform classifications. Finally, we present analytical and computational solutions, which provide the basis for geomorphometric modeling on a triaxial ellipsoid.
Institutional investors affected by hurricanes subsequently support environmental proposals in non-affected firms even if they never voted for similar initiatives. Affected investors raise their holdings in firms where their pro-environment votes are consequential. The increased voting support after hurricanes has real effects as environmental proposals endorsed by more hurricane-afflicted investors are more likely to pass. Moreover, both market capitalization and analysts’ recommendations decline after firms pass environmental proposals. Our evidence suggests that natural disasters raise institutional investors’ concerns about the environment and about potential fund flow disruptions. These concerns, in turn, influence environmental activism, corporate policies, and firm performance.
Virtual Power Plants (VPPs) play a crucial role in the increasing grid and market integration of distributed energy resources. However, as VPP complexity and geographic scale increase, the variable nature of PV generation makes accurate prediction of the VPP aggregate output challenging. The problem is further exacerbated by the paucity of smart meter data, making some prosumers unobservable to the VPP aggregator. To address these challenges, we propose a Bayesian Vector Autoregression approach to quantify the generation variance of a VPP consisting of an aggregation of residential rooftop PV systems spread over a large geographical area. The key idea is to generate synthetic data for unobserved prosumers using observed prosumers’ local correlation microstructure and temporal cross-correlation, allowing the simulation of the VPP output. We demonstrate the efficacy of the proposed approach by using two different Australian data sets. We study two use cases, considering the impact of the level of prosumer observability and the VPP size on the variance of the aggregate VPP output. Compared to the existing approaches, the proposed nonparametric approach provides a more accurate forecast of VPP output variance, allowing the VPP operator to manage market risk better.
Objective
To quantify quality of care following an admission to a nursing home with low or high antipsychotic drug use.
Background
Misuse of antipsychotics in U.S. nursing homes is a huge concern for policymakers.
Methods
We utilized an instrumental variable approach to estimate the effect of facility-level antipsychotic use on patient outcomes. The instrument was the differential distance to the nearest low-use antipsychotic nursing home relative to the nearest high-use antipsychotic nursing home. Post-acute care short-stay and long-stay residents in U.S. nursing homes were identified using Medicare administrative claims and the Minimum Dataset 3.0 (2014–2019). Outcomes included hospitalizations, falls, pressure ulcers, physical restraint use, medication use, and diagnosis of schizophrenia, bipolar disease, anxiety, or depression.
Results
Among long-stay residents, receiving care from a low-use facility reduced the diagnosis of schizophrenia, use of restraints, and hospitalizations. There was also a reduction in the hospitalization rate [−0.9 percentage point (pp)], likelihood of long-stay status (−1.8 pp), and diagnosis of schizophrenia (−0.2 pp) at 90 days among short-stay residents. We also observed larger reductions among residents with dementia and serious mental illness.
Conclusions
Admission to a nursing home with a low use of antipsychotics led to decreased hospitalizations, restraint use, and diagnosis of schizophrenia. Curbing the high use of antipsychotics remains a priority of policymakers as the centers for medicare and medicaid services conducts off-site audits to assess whether nursing homes accurately code residents with schizophrenia. It will be important to monitor if centers for medicare and medicaid services downgrades any quality star ratings due to inappropriate coding and assess the implications on quality of care.
The direct geodesic problem on an oblate spheroid is described as an initial value problem and is solved numerically in geodetic and Cartesian coordinates. The geodesic equations are formulated by means of the theory of differential geometry. The initial value problem under consideration is reduced to a system of first-order ordinary differential equations, which is solved using a numerical method. The solution provides the coordinates and the azimuths at any point along the geodesic. The Clairaut constant is not assumed known but it is computed, allowing to check the precision of the method. An extended data set of geodesics is used, in order to evaluate the performance of the method in each coordinate system. The results for the direct geodesic problem are validated by comparison to Karney's method. We conclude that a complete, stable, precise, accurate and fast solution of the problem in Cartesian coordinates is accomplished.
The era of live-broadcast is back but with two major changes. First, unlike traditional TV broadcasts, content is now streamed over the Internet enabling it to reach a wider audience. Second, due to various user-generated content platforms it has become possible for anyone to get involved, streaming their own content to the world. This emerging trend of going live usually happens via social platforms, where users perform live social broadcasts predominantly from their mobile devices, allowing their friends (and the general public) to engage with the stream in real-time. With the growing popularity of such platforms, the burden on the current Internet infrastructure is therefore expected to multiply. With this in mind, we explore one such prominent platform - Facebook Live. We gather 3TB of data, representing one month of global activity and explore the characteristics of live social broadcast. From this, we derive simple yet effective principles which can decrease the network burden. We then dissect global and hyper-local properties of the video while on-air, by capturing the geography of the broadcasters or the users who produce the video and the viewers or the users who interact with it. Finally, we study the social engagement while the video is live and distinguish the key aspects when the same video goes on-demand. A common theme throughout the paper is that, despite its name, many attributes of Facebook Live deviate from both the concepts of live and broadcast.
Research Summary
This study explores the decision to centralize control over technological resources. We posit that opportunity costs arising from the firm's administrative structure impact this choice. These opportunity costs stem from differences in identifying and evaluating opportunity sets between the unit level (decentralized) and headquarters level (centralized). We propose that a resource's versatility increases the opportunity costs associated with decentralized control, thereby raising the likelihood of its control being centralized. Using a sample of patents acquired through corporate acquisitions in the medical device industry, we find that patents with greater technological and product‐market versatility are more likely to be reassigned to the central level. These findings contribute to elucidating the interplay between resources, strategy, and structure.
Managerial Summary
In the process of integrating a newly acquired firm, acquirers must decide whether to retain the resources within the acquired subsidiary or reallocate them to the headquarters. Decentralizing resources enables managers at the divisional level to spot, sort, select, and seize opportunities in their specific product‐market domains. However, centralizing resources can help exploit opportunities with a broad scope, spanning across divisions. The key consideration is determining which resources should be centralized after an acquisition? Analysis of data on 507 US acquisitions in the medical device industry undertaken between 1996 and 2015 reveals that acquirers tend to centralize versatile technological resources, especially when the acquirers themselves have a diverse technological base.
Existing equations for computation of meridional distance from latitude and for computation of latitude from meridional distance are modified to forms which are suitable for programming for electronic desk computers. Certain constants are given for ellipsoids in common use. Some programming hints are also included.
Existing equations for computation of meridional distance from latitude and for computation of latitude from meridional distance are modified to forms which are suitable for programming for electronic desk computers. Certain constants are given for ellipsoids in common use. Some programming hints are also included.
It would be reasonable to suppose that if the formulae given by Rainsford in [1] were extended still further, there would be terms of greater than fifth order, elliptic and otherwise; and that of these, the elliptic would be of less importance. Now it is easy to see that all such terms that are not elliptic, obtained by putting the eccentricity = 0, could be provided by “closed” spherical formulae. Rainsford's extension was tested at 1000 miles in [2], and showed differences of up to 16·7 metres in distance and 0·70″ in azimuth. The “Spherical” Gauss system came in to 0·0 metres in length and 0·00″ in forward and back azimuths for all of the nine test lines. The numerical results are given later in detail.
Improved practical and theoretical formulas are presented for the calculation of geodetic distances, azimuths, and positions
on a spheroid. The formulas are designed for use with either electronic computers or desk calculators. For the latter, the
formulas lend themselves to the construction of useful interpolation tables.
The report includes convenient computation forms and auxiliary equations which assure a high degree of accuracy for any geodetic
line, no matter how short or long (up to half or fully around the earth) and regardless of its orientation or location. Numerical
examples illustrate the complete calculation procedure.
This article examines the practical application of formulae for computing long lines on the ellipsoid. The main aim is to eliminate the successive approximation generally required. For the inverse problem, this is achieved by the method ofE. M. Sodano, Army Map Service, U.S.A. An adaptation of a method produced byG. T. McCaw is used for the direct problem.
Results are given of five practical examples, including two which extend halfway round the world. Construction of further special tables is recommended to simplify the computations required by a problem which has an ever increasing application.
Geometric geodesy notes, The Ohio State Univ
- R H Rapp
Rapp, R. H. Geometric geodesy notes, The Ohio State Univ., 1969.
Geodetic Survey of Canada Publication No
- W M Tobey
- Geodesy
Tobey, W. M. Geodesy, Geodetic Survey of Canada Publication No. 11, 1928.