Search results

11 – 20 of over 2000
Article
Publication date: 1 April 2006

Derek J. Paulsen

The purpose of this paper is to conduct an independent analysis of all existing geographic profiling software packages to determine if any one is more accurate than the others or…

2648

Abstract

Purpose

The purpose of this paper is to conduct an independent analysis of all existing geographic profiling software packages to determine if any one is more accurate than the others or if any of the software systems are any more accurate than simple spatial distribution strategies at locating the home base of serial offenders.

Design/methodology/approach

An analysis was conducted of all existing geographic profiling software as well as three spatial distribution methods of profiling. Differences in accuracy were assessed using four different methods; dichotomous profile accuracy, simple error measurement, profile error distance, and average top profile area.

Findings

Results indicate that not only are the different profiling software systems no more accurate than the spatial distribution control methods, but that accuracy in general was marginal at best. In addition results indicated that certain crimes, such as commercial robbery, were particularly difficult to profile and that the number of crimes in a series was not by itself a good indicator of success of a profile.

Research limitations/implications

The paper shows that future research needs to focus more on determining how various factors such as city type, crime type, road network and spatial aspects of a crime series (dispersion and search area) impact profiling accuracy. In addition future research should also endeavor to determine whether these advanced strategies are substantially more accurate than other simple profiling strategies such as human prediction. Finally, future research should also seek to examine geographic profiling in a real world setting and how geographic profiling impacts the success of open investigations.

Practical implications

Practically, this study casts doubt not only on the overall accuracy of profiling strategies in predicting the likely home location of an offender, but also on whether probability strategies are substantially better than spatial distribution strategies.

Originality/value

This research was the first to independently analyze all of the existing geographic profiling systems against control methods for the purpose of determining the accuracy of these different methods.

Details

Policing: An International Journal of Police Strategies & Management, vol. 29 no. 2
Type: Research Article
ISSN: 1363-951X

Keywords

Article
Publication date: 7 March 2016

Frank Holzäpfel, Anton Stephan, Tobias Heel and Stephan Körner

From pilot reports, field measurements and numerical simulations, it is known that wake vortices may persist within the glide path in ground proximity, leading to an increased…

Abstract

Purpose

From pilot reports, field measurements and numerical simulations, it is known that wake vortices may persist within the glide path in ground proximity, leading to an increased encounter risk. This paper aims to investigate wake vortex behaviour during final approach and landing to understand why landings can be safe nevertheless. Further, it is investigated whether and to which extent the installation of plate lines beyond the runway tails may further accelerate wake vortex decay and thus improve safety by reducing the number of wake vortex encounters.

Design/methodology/approach

A hybrid numerical simulation approach is used to investigate vortex evolution from roll-up until final decay during the landing manoeuvre. The simulations are complemented by field measurement data accomplished at Munich Airport and at Special Airport Oberpfaffenhofen.

Findings

During touchdown, the so-called end effects trigger pressure disturbances and helical vortex structures that appear to ensure vortex decay rates in ground proximity needed to guarantee the required safety targets of aviation. Light detection and ranging (LIDAR) measurements indicate that vortex decay indeed can be accelerated by a plate line installed on the ground surface. The lifetime of the most safety relevant, long-lived and strongest vortices can be reduced by one-third.

Practical implications

The installation of plate lines beyond the runway tails may improve safety by reducing the number of wake vortex encounters and increase the efficiency of wake vortex advisory systems.

Originality/value

The novel numerical simulation technique and the acquired insights into the wake vortex phenomena occurring during landing as well as the demonstration of the functionality of the patented plate line provide high originality and value for both science and operational application.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 88 no. 2
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 1 January 1984

Peter Bettess and Jacqueline A. Bettess

This paper is concerned with static problems, i.e. those which do not change with time. Dynamic problems will be considered in a sequel. The historical development of infinite…

Abstract

This paper is concerned with static problems, i.e. those which do not change with time. Dynamic problems will be considered in a sequel. The historical development of infinite elements is described. The two main developments, decay function infinite elements and mapped infinite elements, are described in detail. Results obtained using various infinite elements are given, followed by a discussion of possibilities and likely developments.

Details

Engineering Computations, vol. 1 no. 1
Type: Research Article
ISSN: 0264-4401

Article
Publication date: 1 December 1994

Jim Millington

Reviews a number of contributions to migration analysis. Discusses someof the rudiments of migration modelling before turning attention tospecific applications. Pays particular…

3411

Abstract

Reviews a number of contributions to migration analysis. Discusses some of the rudiments of migration modelling before turning attention to specific applications. Pays particular attention to articles which have modelled the interaction between labour and housing markets.

Details

International Journal of Manpower, vol. 15 no. 9
Type: Research Article
ISSN: 0143-7720

Keywords

Article
Publication date: 7 December 2020

Ti-Ching Peng

Population ageing is fast becoming a major social concern across the globe. This ageing trend unavoidably fuels elders’ demand for healthcare services. As the main users of health…

Abstract

Purpose

Population ageing is fast becoming a major social concern across the globe. This ageing trend unavoidably fuels elders’ demand for healthcare services. As the main users of health care service, whether the healthcare is geographically approachable in local areas is more imperative to senior residents with restricted mobility. This paper proposes to examine the effect of elders’ healthcare accessibility on property prices of Taipei Metropolis, Taiwan.

Design/methodology/approach

Luo and Qi’s (2009) enhanced two-step floating catchment area method – taking both healthcare demand and supply into account – was used to measure three types of healthcare services: “physician-to-elder ratio”, “hospital bed-to-elder ratio” and “ambulance-to-elder ratio”. Spatial quantile regression (SQR) model was then used to examine the spatial effect of healthcare accessibility on different property price ranges.

Findings

The “physician-to-elder ratio” and “hospital bed-to-elder ratio” demonstrated expected consistent positive effects across all quantiles of property prices (p < 0.01) in SQR, and its effects aggravated as the quantiles of property prices rose. The “ambulance-to-elder ratio” demonstrated a non-linear influence on property prices (i.e. a negative effect on lowest quantile prices but a positive on higher quantile prices) possibly due to the semi-obnoxious characteristic of the ambulance. That is, residents living in lower priced neighbourhoods may dislike ambulances’ annoying sound of sirens (i.e. ambulances’ disamenity), while residents living in higher valued neighbourhoods may on the contrary appreciate ambulances’ healthcare services (i.e. amenity).

Practical implications

These findings are expected to offer some insights for government’s policies in providing elders in their later years with good residential quality and easy access to healthcare resource.

Originality/value

This paper is one of the few studies that consider the capitalization of the spatial healthcare accessibility to elders into property prices. In this ageing trend across the globe, although all the accessibility to medical resources should be equally critical, the application of spatial quantile regression revealed residents’ inconsistent tendency against semi-obnoxious ambulances. It provides a different perspective in defining the importance of healthcare accessibility in neighbourhoods.

Details

International Journal of Housing Markets and Analysis, vol. 14 no. 5
Type: Research Article
ISSN: 1753-8270

Keywords

Article
Publication date: 16 November 2018

Michael J. McCord, Sean MacIntyre, Paul Bidanset, Daniel Lo and Peadar Davis

Air quality, noise and proximity to urban infrastructure can arguably have an important impact on the quality of life. Environmental quality (the price of good health) has become…

Abstract

Purpose

Air quality, noise and proximity to urban infrastructure can arguably have an important impact on the quality of life. Environmental quality (the price of good health) has become a central tenet for consumer choice in urban locales when deciding on a residential neighbourhood. Unlike the market for most tangible goods, the market for environmental quality does not yield an observable per unit price effect. As no explicit price exists for a unit of environmental quality, this paper aims to use the housing market to derive its implicit price and test whether these constituent elements of health and well-being are indeed capitalised into property prices and thus implicitly priced in the market place.

Design/methodology/approach

A considerable number of studies have used hedonic pricing models by incorporating spatial effects to assess the impact of air quality, noise and proximity to noise pollutants on property market pricing. This study presents a spatial analysis of air quality and noise pollution and their association with house prices, using 2,501 sale transactions for the period 2013. To assess the impact of the pollutants, three different spatial modelling approaches are used, namely, ordinary least squares using spatial dummies, a geographically weighted regression (GWR) and a spatial lag model (SLM).

Findings

The findings suggest that air quality pollutants have an adverse impact on house prices, which fluctuate across the urban area. The analysis suggests that the noise level does matter, although this varies significantly over the urban setting and varies by source.

Originality/value

Air quality and environmental noise pollution are important concerns for health and well-being. Noise impact seems to depend not only on the noise intensity to which dwellings are exposed but also on the nature of the noise source. This may suggest the presence of other externalities that arouse social aversion. This research presents an original study utilising advanced spatial modelling approaches. The research has value in further understanding the market impact of environmental factors and in providing findings to support local air zone management strategies, noise abatement and management strategies and is of value to the wider urban planning and public health disciplines.

Details

Journal of European Real Estate Research, vol. 11 no. 3
Type: Research Article
ISSN: 1753-9269

Keywords

Article
Publication date: 1 March 1997

Maurice Godwin and David Canter

The locations at which each of 54 US serial killers, who had each killed at least ten people, first encountered their victims (PFE) and later dumped their bodies (BD) were…

3221

Abstract

The locations at which each of 54 US serial killers, who had each killed at least ten people, first encountered their victims (PFE) and later dumped their bodies (BD) were examined in relation to the residence of the offender in order to test three hypotheses: the home tended to be a geographical focus for the crimes; the PFE is more a part of the offender’s daily activities than the BD; and over time the PFE and BD both become incorporated into the offender’s lifestyle. Uses smallest space analysis (SSA) and t‐tests to support all three hypotheses. The home is the center of a two‐dimensional SSA plot. The overall mean distance from home to PFE was 1.46 miles and to BD 14.3 miles. Further, while the means of these distances were significantly different for the first eight offenses they were not for the last two. Discusses implications of these results for police investigations.

Details

Policing: An International Journal of Police Strategies & Management, vol. 20 no. 1
Type: Research Article
ISSN: 1363-951X

Keywords

Article
Publication date: 18 November 2013

John McCord, Michael J. McCord, William McCluskey, Peadar Davis, David McIhatton and Martin Haran

Belfast's “peace walls” exist to physically segregate and provide a measure of security to the communities on the religious divide in Northern Ireland. Whilst they do ostensibly…

Abstract

Purpose

Belfast's “peace walls” exist to physically segregate and provide a measure of security to the communities on the religious divide in Northern Ireland. Whilst they do ostensibly achieve this aim, it may well be that these structures have the capacity to prevent the restoration of normal community interactions and market processes and may also be providing their benefits at a high price with regard to issues such as house price reduction. Indeed, the effect of these structures on surrounding residential property values remains somewhat of an unknown quantity. This paper therefore measures the effect of proximity to locations with social and political conflicts. The paper aims to quantify and measure the disamenity implications and costs of artificial barriers (peace walls) within the Belfast housing market.

Design/methodology/approach

This paper attempts to measure the disamenity effect of peace walls on house prices, primarily focusing on the effect of distance, calculated using a hedonic pricing specification and spatially referenced data. The data are derived from 3,836 house sales transactions over a one year period in 2011.

Findings

The emerging findings demonstrate that a greater negative pricing effect is evident with proximity to the peace walls, with the exception of the apartment sector. The findings also highlight the complex market pricing structure of Belfast and offer insight as how to best classify submarkets.

Practical implications

The results of the research are of particular interest to property valuers and social policy makers in regions with contested space.

Originality/value

Tactile barriers scar the urban terrain, formalise ethno-segregation across Belfast and have implications for spatial planning in the urban environment and housing studies and policy. Such an externality may have a pervasive and endogenous effect on house prices and the identification of submarkets yet there is implicit acceptance of peace lines as de facto standard and a dearth of empirical evidence relating to direction and magnitude of the location-specific effects of peace walls on house prices in Belfast. This paper is arguably the first to empirically examine the location-specific effects of peace walls on property value across the Belfast area.

Details

Journal of European Real Estate Research, vol. 6 no. 3
Type: Research Article
ISSN: 1753-9269

Keywords

Article
Publication date: 15 February 2020

Yunpeng Wang and Roger E. Khayat

The purpose of this study is to examine theoretically the axisymmetric flow of a steady free-surface jet emerging from a tube for high inertia flow and moderate surface tension…

Abstract

Purpose

The purpose of this study is to examine theoretically the axisymmetric flow of a steady free-surface jet emerging from a tube for high inertia flow and moderate surface tension effect.

Design/methodology/approach

The method of matched asymptotic expansion is used to explore the rich dynamics near the exit where a stress singularity occurs. A boundary layer approach is also proposed to capture the flow further downstream where the free surface layer has grown significantly.

Findings

The jet is found to always contract near the tube exit. In contrast to existing numerical studies, the author explores the strength of upstream influence and the flow in the wall layer, resulting from jet contraction. This influence becomes particularly evident from the nonlinear pressure dependence on the upstream distance, as well as the pressure undershoot and overshoot at the exit for weak and strong gravity levels, respectively. The approach is validated against existing experimental and numerical data for the jet profile and centerline velocity where good agreement is obtained. Far from the exit, the author shows how the solution in the diffusive region can be matched to the inviscid far solution, providing the desired appropriate initial condition for the inviscid far flow solution. The location, at which the velocity becomes uniform across the jet, depends strongly on the gravity level and exhibits a non-monotonic behavior with respect to gravity and applied pressure gradient. The author finds that under weak gravity, surface tension has little influence on the final jet radius. The work is a crucial supplement to the existing numerical literature.

Originality/value

Given the presence of the stress singularity at the exit, the work constitutes a superior alternative to a computational approach where the singularity is typically and inaccurately smoothed over. In contrast, in the present study, the singularity is entirely circumvented. Moreover, the flow details are better elucidated, and the various scales involved in different regions are better identified.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 April 1992

Bruce Curry and Luiz Moutinho

Considers alternative types of computer models designed to assistdecision makers on questions of site location. Relates to a larger scaleresearch project which aims to examine the…

Abstract

Considers alternative types of computer models designed to assist decision makers on questions of site location. Relates to a larger scale research project which aims to examine the necessary requirements for computers to provide practical decision support. It involves comparing a wide range of modelling techniques, with a view to establishing their relative strengths and the conditions under which each would be the most appropriate choice. Discusses the range of modelling techniques available and provides a more detailed review of one particular model which combines a “conventional” approach, based on algebraic equations, with an expert systems approach.

Details

International Journal of Retail & Distribution Management, vol. 20 no. 4
Type: Research Article
ISSN: 0959-0552

Keywords

11 – 20 of over 2000