116 research outputs found
The impact and penetration of location-based services
Since the invention of digital technology, its development has followed an entrenched path ofminiaturisation and decentralisation with increasing focus on individual and niche applications. Computerhardware has moved from remote centres to desktop and hand held devices whilst being embedded invarious material infrastructures. Software has followed the same course. The entire process has convergedon a path where various analogue devices have become digital and are increasingly being embedded inmachines at the smallest scale. In a parallel but essential development, there has been a convergence ofcomputers with communications ensuring that the delivery and interaction mechanisms for computersoftware is now focused on networks of individuals, not simply through the desktop, but in mobilecontexts. Various inert media such as fixed television is becoming more flexible as computers and visualmedia are becoming one.With such massive convergence and miniaturisation, new software and new applications define the cuttingedge. As computers are being increasingly tailored to individual niches, then new digital services areemerging, many of which represent applications which hitherto did not exist or at best were rarely focusedon a mass market. Location based services form one such application and in this paper, we will bothspeculate on and make some initial predictions of the geographical extent to which such services willpenetrate different markets. We define such services in detail below but suffice it to say at this stage thatsuch functions involve the delivery of traditional services using digital media and telecommunications.High profile applications are now being focused on hand held devices, typically involving information onproduct location and entertainment but wider applications involve fixed installations on the desktop whereservices are delivered through traditional fixed infrastructure. Both wire and wireless applications definethis domain. The market for such services is inevitably volatile and unpredictable at this early stage but wewill attempt here to provide some rudimentary estimates of what might happen in the next five to tenyears.The ?network society? which has developed through this convergence, is, according to Castells (1989,2000) changing and re-structuring the material basis of society such that information has come todominate wealth creation in a way that information is both a raw material of production and an outcome ofproduction as a tradable commodity. This has been fuelled by the way technology has expanded followingMoore?s Law and by fundamental changes in the way telecommunications, finance, insurance, utilitiesand so on is being regulated. Location based services are becoming an integral part of this fabric and thesereflect yet another convergence between geographic information systems, global positioning systems, andsatellite remote sensing. The first geographical information system, CGIS, was developed as part of theCanada Land Inventory in 1965 and the acronym ?GIS? was introduced in 1970. 1971 saw the firstcommercial satellite, LANDSAT-1. The 1970s also saw prototypes of ISDN and mobile telephone and theintroduction of TCP/IP as the dominant network protocol. The 1980s saw the IBM XT (1982) and thebeginning of de-regulation in the US, Europe and Japan of key sectors within the economy. Finally in the 1990s, we saw the introduction of the World Wide Web and the ubiquitous pervasion of business andrecreation of networked PC?s, the Internet, mobile communications and the growing use of GPS forlocational positioning and GIS for the organisation and visualisation of spatial data. By the end of the 20thcentury, the number of mobile telephone users had reached 700 million worldwide. The increasingmobility of individuals, the anticipated availability of broadband communications for mobile devices andthe growing volumes of location specific information available in databases will inevitably lead to thedemand for services that will deliver location related information to individuals on the move. Suchlocation based services (LBS) although in a very early stage of development, are likely to play anincreasingly important part in the development of social structures and business in the coming decades.In this paper we begin by defining location based services within the context we have just sketched. Wethen develop a simple model of the market for location-based services developing the standard non-linearsaturation model of market penetration. We illustrate this for mobile devices, namely mobile phones in thefollowing sections and then we develop an analysis of different geographical regimes which arecharacterised by different growth rates and income levels worldwide. This leads us to speculate on theextent to which location based services are beginning to take off and penetrate the market. We concludewith scenarios for future growth through the analogy of GIS and mobile penetration
A network-based scan statistic for detecting the exact location and extent of hotspots along urban streets
Socio-economic activities and incidents such as crimes and traffic accidents have a negative impact on our society, and their reduction has been a priority in our social-science endeavour. These events are not uniform in their occurrences but, rather, manifest a distinct set of concentrations, commonly known as hotspots. Detecting the exact extent, shape and changes in these hotspots can lead to deeper understanding of their cause and help reduce the volume of incidents, yet accuracy of the analytical outcomes using existing methods are often hampered by their reliance on Euclidean distance. This paper proposes a new type of cluster detection method for identifying significant concentration of urban and social-science activities recorded at the individual street-address level. It extends Scan Statistic—a regular hotspot detection method originally developed in the field of epidemiology—by introducing flexible search windows that adapt to and sweep across a street network. Using a set of synthetic data of crime incidents as an example, performance of the proposed method is measured against that of its conventional counterparts. Results from the performance tests confirm that the proposed method is more accurate in detecting the exact locations of hotspots without over- or under-representing them, thus offering an effective means to identify problem places at the individual street-address level. The simulation also demonstrates how well the proposed method captures changes in the intensity of hotspots, which is also something existing methods have struggled with. An empirical analysis is carried out with data on drug, burglary, robbery, as well as thefts from vehicles in Chicago. The study demonstrates the capacity of the proposed method to extract the detailed profile of the concentration of each crime type, which offers interesting insights into their micro-scale patterns which were previously not available at such a fine spatial granularity
Multi-UAV Allocation Framework for predictive crime deterrence and data acquisition
The recent decline in the number of police and security force personnel has raised a serious security issue that could lead to reduced public safety and delayed response to crimes in urban areas. This may be alleviated in part by utilizing micro or small unmanned aerial vehicles (UAVs) and their high-mobility on-board sensors in conjunction with machine-learning techniques such as neural networks to offer better performance in predicting times and places that are high-risk and deterring crimes. The key to the success of such operation lies in the suitable placement of UAVs. This paper proposes a multi-UAV allocation framework for predictive crime deterrence and data acquisition that consists of the overarching methodology, a problem formulation, and an allocation method that work with a prediction model using a machine learning approach. In contrast to previous studies, our framework provides the most effective arrangement of UAVs for maximizing the chance to apprehend offenders whilst also acquiring data that will help improve the performance of subsequent crime prediction. This paper presents the system architecture assumed in this study, followed by a detailed description of the methodology, the formulation of the problem, and the UAV allocation method of the proposed framework. Our framework is tested using a real-world crime dataset to evaluate its performance with respect to the expected number of crimes deterred by the UAV patrol. Furthermore, to address the engineering practice of the proposed framework, we discuss the feasibility of the simulated deployment scenario in terms of energy consumption and the relationship between data analysis and crime prediction
Observed Consequences of Presupernova Instability in Very Massive Stars
This chapter concentrates on the deaths of very massive stars, the events
leading up to their deaths, and how mass loss affects the resulting death. The
previous three chapters emphasized the theory of wind mass loss, eruptions, and
core collapse physics, but here we emphasize mainly the observational
properties of the resulting death throes. Mass loss through winds, eruptions,
and interacting binaries largely determines the wide variety of different types
of supernovae that are observed, as well as the circumstellar environments into
which the supernova blast waves expand. Connecting these observed properties of
the explosions to the initial masses of their progenitor stars is, however, an
enduring challenge and is especially difficult for very massive stars.
Superluminous supernovae, pair instability supernovae, gamma ray bursts, and
"failed" supernovae are all end fates that have been proposed for very massive
stars, but the range of initial masses or other conditions leading to each of
these (if they actually occur) are still very certain. Extrapolating to infer
the role of very massive stars in the early universe is essentially
unencumbered by observational constraints and still quite dicey.Comment: 39 pages, 5 figures, to appear as chapter in the book "Very Massive
Stars in the Local Universe", ed. J. Vin
Road junction configurations and the severity of traffic accidents in Japan
In many countries, 40–60% of the traffic accidents occur at junctions, making the reduction of junction accidents paramount to achieving UN Sustainable Development Goals. In Japan, the road safety guidelines specify the proximity between junctions and non-perpendicular angles at junctions as the two main risk factors behind junction accidents, yet their impact remains understudied. Using binomial logistic regression models, this study investigates the impact of junction intervals and junction angles on the severity of traffic accidents. The study found that, in general, (1) shorter intervals between adjacent junctions helps reduce the risk of serious accidents, which is the opposite of the current road safety guidelines in Japan, and (2) results from the junction angle analysis were mixed but there was no evidence that the roads should meet at a right angle to reduce traffic accidents. Some types of accidents also returned a non-linear curve, e.g., vehicle-to-vehicle collisions at four-armed junctions involving a driver aged 65 years and over have the highest risk of fatal/serious accidents when adjacent junctions were 32 m apart, and the risk reduces at a shorter or longer interval. These results suggest that the current road safety guidelines require updating to improve road safety around junctions
Three-dimensional modeling of a primary health care clinic in Ho, Ghana: its contribution to student engagement, fundraising, and program planning
Improvements in computer-based technologies can be leveraged to enhance engagement of remote stakeholders with the health needs of a geographically distant community. Three-dimensional (3D) modeling offers a platform to create detailed spatial representations through which stakeholders can experience improvements in shared understanding as well as increased involvement in community health projects occurring anywhere in the world. This case study describes the development of a 3D model of a community health clinic in rural Ghana used to encourage fundraising and sustain global engagement among students at Northwestern University. The resulting ‘virtual clinic’ was achieved quickly and at little cost, suggesting a broader utility of 3D modeling for global health practitioners for increasing donor engagement and resource mapping
The Evolution of Compact Binary Star Systems
We review the formation and evolution of compact binary stars consisting of
white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and
BHs are thought to be the primary astrophysical sources of gravitational waves
(GWs) within the frequency band of ground-based detectors, while compact
binaries of WDs are important sources of GWs at lower frequencies to be covered
by space interferometers (LISA). Major uncertainties in the current
understanding of properties of NSs and BHs most relevant to the GW studies are
discussed, including the treatment of the natal kicks which compact stellar
remnants acquire during the core collapse of massive stars and the common
envelope phase of binary evolution. We discuss the coalescence rates of binary
NSs and BHs and prospects for their detections, the formation and evolution of
binary WDs and their observational manifestations. Special attention is given
to AM CVn-stars -- compact binaries in which the Roche lobe is filled by
another WD or a low-mass partially degenerate helium-star, as these stars are
thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure
CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in 2018
While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI
The Exceptionally Luminous Type II-L SN 2008es
We report on our early photometric and spectroscopic observations of the
extremely luminous Type II supernova (SN) 2008es. With an observed peak optical
magnitude of m_V = 17.8 and at a redshift z = 0.213, SN 2008es had a peak
absolute magnitude of M_V = -22.3, making it the second most luminous SN ever
observed. The photometric evolution of SN 2008es exhibits a fast decline rate
(~0.042 mag d^-1), similar to the extremely luminous Type II-L SN 2005ap. We
show that SN 2008es spectroscopically resembles the luminous Type II-L SN
1979C. Although the spectra of SN 2008es lack the narrow and intermediate-width
line emission typically associated with the interaction of a SN with the
circumstellar medium of its progenitor star, we argue that the extreme
luminosity of SN 2008es is powered via strong interaction with a dense,
optically thick circumstellar medium. The integrated bolometric luminosity of
SN 2008es yields a total radiated energy at ultraviolet and optical wavelengths
of >10^51 ergs. Finally, we examine the apparently anomalous rate at which the
Texas Supernova Search has discovered rare kinds of supernovae, including the
five most luminous supernovae observed to date, and find that their results are
consistent with those of other modern SN searches.Comment: accepted to ApJ, 10 pages, 7 figures, 6 tables. Minor revisions,
conclusions remain unchange
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