Spatial Density Analysis Research Articles

Times and spaces of crime in the Historic Centre of Porto: Evidence from official data

The analysis of official data is a traditional strategy to study criminality in a geographic space (e.g., city, country). This work focuses on the analysis of the official statistics of crime against property at the Historic Centre of Porto, Portugal, in 2018. It addresses temporal (i.e., by period of the week, time of day) and spatial patterns (i.e., spatial analysis, typology of spaces) of crime occurrences. The database was analyzed through descriptive and inferential statistics, and by spatial density analysis. Theft was the most common type of crime, although crime types varied greatly with location, and time of the day. There were no significant differences on crime occurrences by days of the week and most crimes were reported in the afternoon. Concerning typology of spaces, most crimes occurred at linear spaces, especially robberies. Findings can be very useful for sustainable and considered urban planning, by aligning the location of material and human resources with the detection of seasonal and comparable crime patterns, enabling more efficient crime prevention in urban areas.

Vision-based real-time process monitoring and problem feedback for productivity-oriented analysis in off-site construction

The widespread adoption of surveillance cameras in work environments has enabled the direct and non-intrusive detection of productivity-related issues in the field of construction. In this research, a process monitoring and problem feedback framework is developed based on closed-circuit television footage and computer vision analysis to achieve real-time visual control of the work process and facilitate data-driven decision-making in off-site construction. To enhance the automation of productivity-related problem recognition, a novel video analysis algorithm is developed to process the inputted video footage and provide feedback with respect to nine productivity issues. The z-score and Exponential Moving Average methods are employed to eliminate detection errors, and the spatial density analysis method is adopted to visually analyze spatial information. The observed performance of the proposed framework demonstrates that it can accurately acquire data from footage and provide process monitoring and problem feedback in real time.

Exploring spatial patterns and environmental risk factors for global maritime accidents: A 20-year analysis

The global shipping industry faces increasingly complex safety challenges due to the rapid growth of international maritime trade. This study develops a novel framework that combines spatial density analysis and machine learning (i.e., extreme gradient boosting model) to investigate the evolutionary patterns of global maritime accidents during 2001–2020 from both spatial and temporal dimensions, and then identifies key environmental risk factors affecting maritime safety. The results show that the number of global maritime accidents exhibits fluctuations between 2001 and 2019, with a significant decrease observed in 2020. Furthermore, the distribution of global maritime accidents shows significant spatial variation over different time periods. Denmark's sea areas have high accident rates between 2001 and 2005, while concentrated accidents are observed in the seas around the United Kingdom, Denmark, and China between 2006 and 2010. From 2011 to 2015, Europe's accident-prone areas increase, but fewer accidents are reported along China's east coast. The Strait of Malacca is also an accident-prone area from 2016 to 2020. In addition, wave height, sea surface temperature, wind speed, water depth, and precipitation are identified as key environmental risk factors affecting maritime safety. These findings can inform strategies and mitigation plans to improve navigational safety in the global shipping industry.

Experimental study of electron cyclotron heating assisted start-up on J-TEXT

Second harmonic X-mode (X2 mode) electron cyclotron heating (ECH) assisted start-up has been studied experimentally on the J-TEXT device to determine the minimum ECH power requirements to assist breakdown and develop a better physical description of the process. Results indicate that the minimum toroidal electric field for a successful start-up on J-TEXT changed from to , and that injecting of X2-mode ECH power can ensure robust breakdown. The critical ECH power for successful start-up was determined to be approximately . At lower powers ECH was observed to cause ionization, but this did not necessarily result in successful start-up. The effects of varying ECH power, pulse-width and toroidal magnetic field on start-up were also investigated. Higher ECH power leads to quicker, stronger ionization and CIII emission, and is beneficial for burn-through. Higher pre-plasma density caused by high ECH power can decrease the required toroidal electric field for ohmic breakdown, while the enhanced CIII emission may not be good for start-up. The characteristics of the pre-plasma formed by ECH prior to application of the loop voltage were also studied. The toroidal magnetic field affects the initial location where pre-plasma forms and this also affected the subsequent tokamak start-up. The analysis of spatial density showed that the pre-plasma can radially develop at a velocity of . Furthermore, it was found that injecting ECH power at the appropriate time with a low power of can achieve similar pre-ionization results to the high-power case. The transition from ECH plasma to ohmic plasma suggests that the ECH assisted start-up modified the process of purely ohmic breakdown.

A Morphological and Spatial Analysis of Volcanoes on Venus

AbstractVenus is home to many thousands of volcanic landforms that range in size from much less than 5 km to well over 100 km in diameter. Volcanism is clearly a major, widespread process on Venus, and is a principal expression of the planet's secular loss of interior heat. Without sufficient in situ data to clearly determine its internal structure, we can use the morphological and spatial properties of volcanoes across the planet to help place constraints on our understanding of the volcanic characteristics and history of Venus. With the Magellan synthetic‐aperture radar full‐resolution radar map left‐ and right‐look global mosaics at 75 m‐per‐pixel resolution, we developed a global catalog of volcanoes on Venus that contains ∼85,000 edifices, ∼99% of which are <5 km in diameter. We find that Venus hosts far more volcanoes than previously mapped, and that although they are distributed across virtually the entire planet, size–frequency distribution analysis reveals a relative lack of edifices in the 20–100 km diameter range, which could be related to magma availability and eruption rate. Through spatial density analysis of volcanoes alongside assessments of geophysical data sets and proximal tectonic and volcanic structures, we report on the morphological and spatial patterns of volcanism on Venus to help gain new insights into the planet's geological evolution.

Evidence of illegal fishing within the largest Brazilian coastal MPA: Turning a blind eye to the obvious

Illegal fishing is a growing threat to aquatic biodiversity and as a result, marine protected areas (MPAs) have arisen as a suitable alternative for the protection of imperiled biodiversity. The purpose of this study was to map out and analyze the movements of illegal fishing vessels which operate within Área de Proteç ão Ambiental Costa dos Corais (APACC), the largest Brazilian coastal MPA. A dataset from the National Program for Tracking Fishing Vessels by Satellite (PREPS) was used to detect the fishing vessels navigating the waters within the APACC over the period 2013–2020. We performed spatial density analysis with the aim of finding the most widely recorded hotspot regions of illegal fishing and also evaluated whether the illegal lobster-fishing occurred within or outside the fishing seasons. We found that there were 62 fishing vessels operating within the APACC and that 19 of them were engaged in some form of fishing activity in this area. Over the years 2013 and 2020, there were a total number of 15,353 detections (63.9% of the detections were identified as being potentially illegal). Fishing activities were defined as illegal when they occurred during the closed season, within an area where fishing is prohibited, or within less than 4 nautical miles from the coast. These fisheries mainly affect species with economic value, such as lobsters, snappers and groupers, and often involve the use of diving air compressors as a fishing technique. It is thus necessary to design better monitoring systems of these fishing fleets to prevent any conflicts over their operations and ensure an effective conservation of biodiversity.

Quantitative assessment of ground deformation risks, controlling factors and movement trends for onshore petroleum and gas industry using satellite Radar remote sensing and spatial statistics

ABSTRACT A number of productive oil and gas fields are located in the Absheron Peninsula of Azerbaijan. The primary goal of the presented study was to quantitatively assess the ground deformation (subsidence and uplift) rates of oil and gas fields, determine natural and man-made influencing factors and predict deformation trends. Persistent Scatterer Interferometric Synthetic Aperture Radar technique was used for the present studies to detect ground deformation rates and velocities in the Absheron oil and gas fields. The existence of ground deformation processes was observed for the period of 2015–2017 with three hotspots of highest subsidence rates and three hotspots of highest uplift rates in oil and gas fields. The determined maximum displacement rates of subsidence and uplift processes were −26 mm/y and +23 mm/y, respectively. However spatial density analysis of deformation velocity presented the natural patterns of uplift and subsidence tectonic processes. This allowed to determine that two oil and gas fields hold a higher probability of being affected by man-made oil and gas exploration activities, whereas the one oil field is affected by both natural and man-made processes. Geographically Weighted Regression analysis revealed that well concentration and elevation factors provided 32% of explanation to subsidence processes.

Logistics facilities for intra and inter-regional shipping: Spatial distributions, location choice factors, and externality

Existing studies of urban logistics facility locations and their impacts on negative externality tend to focus on the movements of freight that start and end within a metropolitan area and overlook the role of the shipments with origin or destination outside of the urban area – external shipments – in characterizing logistics facilities. This research aims to fill such gap. Focusing on the Tokyo Metropolitan Area, we analyze locations and goods vehicle trips associated with four logistics facility groups that have different splits between intra and inter-regional trips for inbound and outbound shipments. The spatial density analysis and the location choice modeling highlight the differences in the distribution and location choice factors among those groups. The importance of trip distance minimization is more evident for the facilities that serve intra-regional shipments. Furthermore, we show that the traffic impacts of goods vehicle traffic associated with logistics facilities also differ in many ways among the above-mentioned groups. Finally, we discuss the policy insights to address their heterogeneity in the contribution to externality.

Human Settlement Assessment in Jinan From a Facility Resource Perspective

Multisource data, spatial density analysis, and a gravity model were used to evaluate and analyze differentiation and controls of human settlement locations in Jinan, China. The results indicate the following. (a) The spatial distribution of human settlements follows a block-style, is axially extended, and has a multicenter development pattern with a significant circular structure. (b) The distributions of many settlement types are similar to the total settlement distribution. Residential space exhibits the highest correlation with public space, whereas financial space has the smallest correlation with business space. A high matching value for human settlement is found at the junction of the five districts in Jinan, whereas the Pingyin and Shanghe counties exhibit the lowest value. (c) Areas with human settlement exhibit typical hierarchies. Performance is dominated by the five districts, Zhangqiu is subdominant, and other districts represent an edge-dependent hierarchical system. Radial spatial settlement structures are centered on the five districts, with a centripetal and multicentric “western dense, eastern sparse” regional pattern. (d) Topography is the main factor that generates differentiation. Road network density affects the distribution and grade of human settlement areas, gross domestic factor is a key factor that affects the formation of human settlement structures, and population aggregation is a prerequisite for human settlement distribution, as well as a catalytic factor for differentiation of human settlements.

The Comparison Between The Uses of Branchless Banking in Urban and Rural Areas: Geographical Perspective

Branchless Banking is an ICT-based service provided by banks through the provision of agents. The agents are spread in several locations, both in urban and rural areas. This paper is part of a study on The Perceptions of Space and Locations of Urban and Rural Communities: Implications for the Development of Branchless Banking. However, this paper only focuses on how community makes use of branchless banking by comparing its conditions in urban and rural areas and its relations to the field of geography. The area studied in this research are Kulon Progo Regency and Yogyakarta Municipality that located in Yogyakarta Special Province, Indonesia. The method used in this research is quantitative method. The data are collected by structured interview especially to the agent and customers of branchless banking. The agents and customers of branchless banking coordinate locations used as input for spatial density analysis. The other geographic perspective is accessibility analysis using cost distance, this analysis developed from combining Euclidean distance of road and settlement, and slope. The result shows that the use of branchless banking is based on the factor of location that is closer to where they live and how easy the access is. In addition, there are also convenience factors, such as unlimited time for services and familiarity in accessing. Regarding the reasons for the utilization of Branchless Banking in Rural and Urban is almost the same, but for the city of Yogyakarta, the location factor plays a role, while in Kulon Progo the comfort factor is also a consideration. In both urban and rural areas, branchless banking agents are mostly located in residential area. Agents are highly used in the location that is far away from economic services, especially banks. It also shows the same pattern if evidenced by spatial density and accessibility analysis. The perception of societies related to the distance qualitatively has similarities with the results of spatial analysis of density and accessibility. The presence of ICT in banking services in the form branchless banking through an agent can add the concept of banking service development that is not always in the city center, but it can also be rural areas.

A New Global Database of Lunar Impact Craters >1–2 km: 1. Crater Locations and Sizes, Comparisons With Published Databases, and Global Analysis

AbstractThis paper presents a new, global database of lunar impact craters, estimated to be a complete census of all craters with diameters larger than 1–2 km. The database contains over 2 million craters, making it larger in number than any previously published lunar effort by more than a factor of 10. Of those craters, 1.3 million have diameters ≥1 km, approximately 83,000 are ≥5 km, and 6,972 craters are ≥20 km. How the database was constructed along with the reliability of features is described in detail. Comparisons are made with past published databases, demonstrating good agreement for crater size and location. An ellipticity analysis is conducted, illustrating there is no dominant direction for elliptical crater orientation based on location, diameter range, or ellipticity amount, consistent with randomness for craters ≥10 km. A spatial density analysis is described, comparing the spatial density of small versus large craters, and numerous observations about the nonuniformity of the size distributions of craters across the Moon are made. The spatial density is also used in a discussion about kilometer‐scale secondary impact craters and clearly shows that they dominate the crater population in some areas of the lunar surface. This paper presents just a tiny sample of the scientific investigations that could be done with this new crater database.

New insights into the neolithisation process in southwest Europe according to spatial density analysis from calibrated radiocarbon dates

The agricultural way of life spreads throughout Europe via two main routes: the Danube corridor and the Mediterranean basin. Current archaeological literature describes the arrival to the Western Mediterranean as a rapid process which involves both demic and cultural models, and in this regard, the dispersal movement has been investigated using mathematical models, where the key factors are time and space. In this work, we have created a compilation of all available radiocarbon dates for the whole of Iberia, in order to draw a chronological series of maps to illustrate temporal and spatial patterns in the neolithisation process. The maps were prepared by calculating the calibrated 14C date probability density curves, as a proxy to show the spatial dynamics of the last hunter-gatherers and first farmers. Several scholars have pointed out problems linked with the variability of samples, such as the overrepresentation of some sites, the degree of regional research, the nature of the dated samples and above all the archaeological context, but we are confident that the selected dates, after applying some filters and statistical protocols, constitute a good way to approach settlement spatial patterns in Iberia at the time of the neolithisation process.

Rainfall and microbial contamination in Alberta well water

Spatial and seasonal patterns in the positive rates of total coliforms and Escherichia coli in Alberta well water were investigated to gain insight into well water microbial contamination. Analysis was conducted in the presence of total coliforms (77 135 tests) and E. coli (77 132 tests) in well water from 2004 to 2009 along with monthly estimates of precipitation, all of which were aggregated to 13 zones across Alberta by using Voronoi tessellation. Regression combined with autocorrelation analysis was employed to develop wave functions for data assembled in each zone. Precipitation was found to peak in June or July in all 13 regions. The positive E. coli rate was found to peak in June, July or August, but the positive total coliform rate peaked in August, September or October. Spatial statistical analysis revealed a potential association of total coliforms and E. coli with precipitation in two heavily populated basins. Spatial density analysis revealed a cluster of positive tests of total coliforms and E. coli in a narrow spatial extent in June and July of 2005.

Informing the Strategic Rollout of Fast Electric Vehicle Charging Networks with User Charging Behavior Data Analysis

The range limitations of electric vehicle (EV) technology have given rise to range anxiety, identified as one of the main barriers to EV adoption. Range limitation may be a greater barrier for countries or states that are predominantly rural, with few major urban areas, than it is for large cities. This paper presents data recorded in Ireland on the spatial usage patterns of a fast charging network for an extended period. The data are used to assess how the infrastructure is being used and to examine issues relating to urban versus rural usage patterns. Infrastructure rollout strategies are examined in the context of the main findings from this analysis, and a spatial density analysis is presented to examine how a desired density can influence a rollout strategy. The fast charging requirements of urban users were found to differ from those of rural and commuter groups. Urban users tend to charge their vehicles close to their home as a means of extending their local EV range. EV users from other geographic areas tend to charge their vehicles farther from their home. This work indicates that current rollout strategies based primarily on “electric” highway corridors may not be appropriate for all EV users; different infrastructure rollout strategies based on fast charging facility densities and geographic location may be more appropriate.

Spatial distribution and structural analysis of vents in the Lunar Crater Volcanic Field (Nevada, USA)

Volcanoes within monogenetic volcanic fields often are arranged in alignments and clusters, which are related to effects of magma source geometry in the upper mantle, principal stress orientations, and crustal structures on their magma feeding systems. We use cluster analysis with dendrogram, vent morphometric analysis, and field structural data to explore the relationships between volcanoes and tectonic features in the Plio-Pleistocene part of the Lunar Crater Volcanic Field (LCVF; Pancake Range, Nevada, USA), which includes 96 monogenetic volcanic edifices totaling 119 vents. Structural analysis identified three main sets of faults with dip-slip kinematics (mostly normal with a few examples of thrust faults), striking N-S, E-W, and NE-SW. The NE-SW set comprises dip-slip faults with a dominant normal component of movement which are consistent with the modern state of stress based upon the World Stress Map database. Spatial distribution pattern analysis suggests a clustered distribution of vents in the LCVF, and GIS-based spatial density analysis shows that these clusters trend mostly NE-SW. Morphometric study of the monogenetic cones, which provides information on feeder dike orientation where dikes are not directly exposed, suggests dominant NNE-SSW to NE-SW orientations of near-surface inferred dikes. An amount of 27 out of 31 inferred feeder dikes within the LCVF is parallel to the present orientation of the greatest principal horizontal stress (σHmax) as suggested by World Stress Map data derived from hydrofracturing and earthquake focal mechanisms. In some cases, dike strike is parallel with that of pre-existing Quaternary dip-slip faults. We suggest that the spatial distribution of vents is related to domains of different scales of partial melting and compositional heterogeneity in the upper mantle source, which is substantiated by geochemical data. The relationship of feeder dikes with respect to shallow tectonic structures, although somewhat ambiguous at LCVF, is consistent with behavior that is intermediate between volcanic fields with high- and low-long-term magma fluxes.

Analysis of multidimensional aspects of agricultural droughts in Zimbabwe using the Standardized Precipitation Index (SPI)

This study focuses on a framework of methodologies used for analyzing the frequency and spatiotemporal characteristics of agricultural droughts in Zimbabwe from a vulnerability context. By employing an empirical orthogonal analysis method, the study revealed that relatively strong spatial and temporal station drought relationships prevail, making the drought spatiotemporal characteristics of the country to be considered highly homogeneous. Thus, agricultural droughts were characterized temporarily using the Standardized Precipitation Index derived from rainfall data for the longer but sparse data period from 1901 to 2004. At the same time, higher spatial density analysis was achieved from shorter but denser database for the period 1941 to 1999. The results indicated that drought is a natural climatic feature of the region and occurs from time to time in defined periods. However, severe and extreme droughts tend to concentrate near the end of the time series, suggesting that during the earlier period of the twentieth century, droughts have been smaller or less pervasive. The extreme droughts appear to inherit the coincidence of both very high values of spatial extent and intensity in a single event. This offers a possible explanation to why extreme droughts in Zimbabwe usually have dire consequences on agriculture and the national economy. By showing that the related national drought impacts on staple maize food production can be estimated, this study has demonstrated that it is possible to anticipate future drought hazard impacts and predict periods of food insecurity. As far as the forecasting of agricultural droughts is concerned, the recently discovered Indian Ocean dipole/zonal mode seems to perform better than the traditional El Nino–Southern Oscillation as a potential drought predictor during the twentieth century.

A spatial density analysis technique for the automatic classification of 4/spl pi/ detector data

In nuclear physics at intermediate energies, the use of multidetector arrays consisting of thousands of detectors is customary. This paper presents a novel approach to the automatic classification of data collected by the 4/spl pi/ detector CHIMERA, constituted by 1192 telescopes of a thin silicon transparent detector coupled to a thick CsI(Tl) scintillator. The method is based on spatial density data processing and produces frequency distributions of the most significant physical parameters. These one-dimensional spectra can be more easily analyzed than the standard two-dimensional scatter plots. With respect to manual or semiautomatic procedures, presently used for data analysis, our method offers the advantages of drastic time reduction and unbiased criteria for cluster identification. The proposed method can be successfully used in both off-line data analysis and multidetector stability control.

Descriptive econometrics for non‐stationary time series with empirical illustrations

AbstractRecent work by the author on methods of spatial density analysis for time series data with stochastic trends is reviewed. The methods are extended to include processes with deterministic trends, formulae for the mean spatial density are given, and the limits of sample moments of non‐stationary data are shown to take the form of moments with respect to the underlying spatial density, analogous to population moments of a stationary process. The methods are illustrated in some empirical applications and simulations. The empirical applications include macroeconomic data on inflation, financial data on exchange rates and political opinion poll data. It is shown how the methods can be used to measure empirical hazard rates for inflation and deflation. Empirical estimates based on historical US data over the last 60 years indicate that the predominant inflation risks are at low levels (2–6%) and low two‐digit levels (10–12%), and that there is also a significant risk of deflation around the −1% level. Copyright © 2001 John Wiley & Sons, Ltd.

Approximation Methods in Discrete Spatial Density Analysis for Finite Populations

The author's three-parameter square-root model for the measurement of discrete spatial density in human populations was previously derived under the assumption that exact coordinate locations of the density points were available. The model, called the population density index (PDI) model, has been expanded to include a set of routines for calculating two-dimensional spatial density measures based upon in situ geometric approximations of the interobject Euclidean distance measure for any finite sample size. The derivation and specification of the algorithm for the abbreviated calculation routines are presented and exemplified. The author has been able to apply the methods of the PDI model to submarine environments at the U.S. Naval Underwater Systems Center, resulting in several U.S. Patent applications.