Weekly Crime Concentration

Objectives: Examine and visualise the temporal concentration of different crime types and detect if their intensity varies through distinct moments of the week. Methods: The “heartbeat of the crime signal” is constructed by overlapping the weekly time they were suffered. This study is based on more than 220,000 crimes reported to the Mexico City Police Department between January 2016 and March 2020 to capture the day and time of crimes and detect moments of the week in which the intensity exceeds the average frequency. A new metric for the temporal concentration of crime is constructed for different types of crime and regions of the city based on the corresponding heartbeats. Results: The temporal concentration of crime is a stable signature of different types of crime. The intensity of robberies and theft is more homogeneous from Monday to Sunday, but robberies of a bank user are highly concentrated in a week, meaning that few hours of the week capture most of the burning moments. The concentration is not homogeneously distributed in the city, with some regions experiencing a much higher temporal concentration of crime. Conclusions: Crime is highly concentrated when observed in its weekly patterns, but different types of crime and regions exhibit substantially distinct concentration levels. The temporal trace indicates specific moments for the burning times of different types of crime, which is a critical element of a policing strategy

A re-examination of the Meyers and Volbrecht motor equation for the identification of suspect effort

Neuropsychologists are frequently called upon to evaluate cognitive functioning and to participate in determining disability status, particularly in the wake of traumatic brain injuries, strokes, and other health events that compromise central nervous system functioning. A critical component of each evaluation is effort assessment. Ideally, the methods for assessing the credibility of effort are neither obvious to test-takers nor vulnerable to coaching. One of the promising ways to evaluate effort is to use a combination of test scores that assess a common domain, such as motor functioning. The purpose of the present study was to cross validate a linear regression formula developed by Meyers and Volbrecht (2003) to evaluate the credibility of effort on selected tests of motor functioning. The formula utilized scores from the Rey-Osterrieth Complex Figure Test, the WAIS-III Digit Symbol and Block Design subtests, and the Finger Tapping Test. The advantages of such a formula for evaluating effort include that it relies upon embedded measures, resulting in heightened efficiency and greater subtlety of assessment. The current archival study re-examined the Meyers and Volbrecht (2003) formula using 281 ethnically diverse patients who were referred for neuropsychological evaluation. The sample included 101 patients who met criteria for noncredible effort and 180 patients who met criteria for credible effort. Cut-off scores for the formula were selected to maintain specificity in the credible patients of at least 90%. The associated sensitivity rate when the original cut-offs were applied to the noncredible group was 30.7%. Closer examination of the individual tests that comprised the formula revealed that the Finger Tapping Test had unacceptably low sensitivity (29.7%). Therefore, the Finger Tapping component of the equation was removed, which increased the formula\u27s sensitivity to 70.3% while maintaining specificity of at least 90%. The revised formula provides neuropsychologists a novel way to assess effort that is neither vulnerable to coaching nor adds time to the testing battery. Other findings, limitations of the current study, and recommendations for future research are discussed

Investigation on the Use of Small Aperture Telescopes for LEO Satellite Orbit Determination

The following thesis regards the use of small aperture telescopes for space domain awareness efforts. The rapidly populating space domain was motivation for the development of a new operation scheme to conduct space domain awareness feasibility studies using small telescopes. Two 14-inch Schmidt-Cassegrain Telescopes at the California Polytechnic State University and the Air Force Research Lab in Kirtland AFB, NM, in conjunction with a dedicated CCD camera and a commercial DSLR camera, were utilized to conduct optical observations on satellites in Earth orbit. Satellites were imaged during August 2019, and from January 2020 to March 2020, resulting in the collection of 77 valid images of 16 unique satellites. These images were used to obtain celestial spherical coordinates, which were used in Gauss and Double-R angles-only initial orbit determination methods. Initial orbit determination methods successfully produced valid results, reaffirming the feasibility of using small aperture telescopes for such methods. These orbit determinations were used to propagate orbit states forward in time to determine the feasibility of future imaging of the targets with the same apparatus. Propagation results demonstrated that initial orbit determinations rapidly decayed in accuracy over distant times and are most accurate for immediate satellite passes. In addition, an attempt to combine multiple initial orbit determinations using Lambert’s problem solutions was made. Combination of these multiple initial orbit determinations resulted in either no orbit state accuracy improvement compared to individual initial orbit determinations, or a decrease in accuracy compared to these methods. Ultimately, efforts demonstrated that small telescope usage is feasible for orbit determination operations, however there may be a need for hardware and operational revisions to improve the ability of the apparatus

Modelling the fear of crime

How secure people feel in a particular region is obviously linked to the actual crime suffered in that region but the exact relationship between crime and its fear is quite subtle. Two regions may have the same crime rate but their local perception of security may differ. Equally, two places may have the same perception of security even though one may have a significantly lower crime rate. Furthermore, a negative perception might persist for many years, even when crime rates drop. Here, we develop a model for the dynamics of the perception of security of a region based on the distribution of crime suffered by the population using concepts similar to those used for opinion dynamics. Simulations under a variety of conditions illustrate different scenarios and help us determine the impact of suffering more, or less, crime. The inhomogeneous concentration of crime together with a memory loss process is incorporated into the model for the perception of security, and results explain why people are often more fearful than actually victimized; why a region is perceived as being insecure despite a low crime rate; and why a decrease in the crime rate might not significantly improve the perception of security

Muchas emergencias y aún más llamadas

Optimizar la distribuci´on y el despacho de los recursos es un tema prioritario en la atenci´on a emergencias, por lo que identificar las posibles llamadas que provienen de un mismo evento resulta determinante para su correcta atenci´on. Se analizar´a el problema tomando en cuenta las caracter´ısticas de una llamada de emergencia y los datos disponibles a partir de los cuales se pueden relacionar distintos reportes y, mediante un modelo de regresi´on log´ıstica, se encontrar´an criterios ´optimos para relacionar dos reportes

Scaling Beyond Cities

City population size is a crucial measure when trying to understand urban life. Many socio-economic indicators scale superlinearly with city size, whilst some infrastructure indicators scale sublinearly with city size. However, the impact of size also extends beyond the city’s limits. Here, we analyse the scaling behaviour of cities beyond their boundaries by considering the emergence and growth of nearby cities. Based on an urban network from African continental cities, we construct an algorithm to create the region of influence of cities. The number of cities and the population within a region of influence are then analysed in the context of urban scaling. Our results are compared against a random permutation of the network, showing that the observed scaling power of cities to enhance the emergence and growth of cities is not the result of randomness. By altering the radius of influence of cities, we observe three regimes. Large cities tend to be surrounded by many small towns for small distances. For medium distances (above 114 km), large cities are surrounded by many other cities containing large populations. Large cities boost urban emergence and growth (even more than 190 km away), but their scaling power decays with distance