Crime Mapping and the Training Needs of Law Enforcement

This paper explores some of the more recent developments within crime mapping and the broader application of geographical information technology within law enforcement. The information technology (IT) revolution and the reduction in computing costs since the 1980s has brought a range of analytical tools within the budgets of most police services, and one of the most significant changes has been in the way that spatial data are handled. Law enforcement has strong geographic currents at all levels of the organisation, and this paper examines three applications of geographical information systems (GIS) within policing: hotspot mapping; CompStat; and geographic profiling. The paper concludes by discussing the future training needs using a simple model of intelligence-led crime reduction. This model suggests that training for managers to enable a greater understanding of the analyses presented to them, and how to use mapping to further crime prevention and reduction, may be as important as increasing the technical ability of crime analysts. The challenge for the immediate future of crime reduction practice in law enforcement is less to worry about the training of analysts, and more to address the inability of law enforcement management to understand and act on the crime analysis they are given.     

Measuring the Geographical Displacement and Diffusion of Benefit Effects of Crime Prevention Activity

The displacement of crime is an important criminological phenomenon. However, while there has been theoretical discussion of this issue in the research literature, there has been little in the way of either standardized empirical work that investigates the incidence of displacement or in the development of techniques that can be used to measure it. In the current paper we discuss a new technique, the weighted displacement quotient (WDQ), that was developed to measure the geographical displacement of crime. A critical feature of the rationale is that displacement can only be attributed to crime prevention activity if crime is reduced in the target area considered. Thus, the WDQ not only measures what occurs in a buffer (displacement) zone but also relates changes in this area to those in the target area. Part of the appeal of the measure is that it can be used either with aggregate or disaggregate crime data and for any geographical boundary selected, provided the appropriate data are available. In addition to detecting displacement, when detailed data are available, the technique can also be used to identify where the effect was most prominent. The WDQ can equally be used to measure the diffusion of benefit of any crime prevention activity. A series of examples are presented for illustration purposes.     

On The Application of Fuzzy Clustering for Crime Hot Spot Detection

   One of the fundamental challenges in crime mapping and analysis is pattern recognition. Efforts and methods to detect crime hot-spots, or geographic areas of elevated criminal activity, are wide ranging. For aggregate data, such as total crime events in a census tract(s), measures of spatial autocorrelation have proven useful. For disaggregate data (i.e. individual crime events), kernel density smoothing and non-hierarchical cluster analysis (e.g. k-means), are widely used. Non-hierarchical techniques are particularly effective in delineating geographic space into areas of higher or lower crime concentrations, because each observation is assigned to one and only one cluster. The resulting set of partitions provides clear-cut spatial boundaries that can be used for hot-spot evaluation and interpretation. However, the strength of non-hierarchical methods can also be viewed as a weakness. Although the hard-clustering of observations into a set of discrete clusters is helpful, there are many cases where ambiguity exists in the data. In such cases, a more generalized approach for hot-spot detection would be helpful. The purpose of this paper is to explore the use of a generalized partitioning method known as fuzzy clustering for hot-spot detection. Functional and visual comparisons of fuzzy clustering and two hard-clustering approaches (medoid and k-means), across a range of cluster values are analyzed. The empirical results suggest that a fuzzy clustering approach is better equipped to handle intermediate cases and spatial outliers.

Using National Incident-Based Reporting System Data for Strategic Crime Analysis

The utility of the National Incident-Based Reporting System (NIBRS) forstrategic crime analysis has yet to be explored. The NIBRS represents anadvancement over existing reporting systems and possesses considerableutility to frontline law enforcement with respect to strategic crimeanalysis. This paper discusses the utility of the NIBRS for identifyinglocal and regional trends in narcotics related offenses. As an example, weselected four localities from the 1997 Virginia NIBRS data to examine trendsin the sale/distribution and possession of narcotics. Our analysis showsthat the NIBRS provides significantly more incident-related detail than hasheretofore been available for strategic crime analysis at the regional orstate level. Moreover, the NIBRS provides neighboring communities theopportunity to compare information on emerging crime patterns and criminalenterprises which extend beyond local boundaries. Finally, enhancing localreporting compliance by highlighting the strategic utility of the data tolocal law enforcement will ultimately ensure the quality of the data set,which can then be employed by larger entities as well as criminal justiceresearchers for policy development and planning.     

Developing a Spatial-Temporal Method for the Geographic Investigation of Shoeprint Evidence

Abstract:  This article examines the potential of a spatial-temporal method for analysis of forensic shoeprint data. The large volume of shoeprint evidence recovered at crime scenes results in varied success in matching a print to a known shoe type and subsequently linking sets of matched prints to suspected offenders. Unlike DNA and fingerprint data, a major challenge is to reduce the uncertainty in linking sets of matched shoeprints to a suspected serial offender. Shoeprint data for 2004 were imported from the Greater London Metropolitan Area Bigfoot database into a geographic information system, and a spatial-temporal algorithm developed for this project. The results show that by using distance and time constraints interactively, the number of candidate shoeprints that can implicate one or few suspects can be substantially reduced. It concludes that the use of space-time and other ancillary information within a geographic information system can be quite helpful for forensic investigation.     

Gang Activity and Overall Levels of Crime: A New Mapping Tool for Defining Areas of Gang Activity Using Police Records

In this note, a new method for defining gang activity areas based uponpolice records is illustrated using the Chicago Police Department's1996 incident files. This method is based upon standard geographictechniques and uses a uniform grid that divides the city into 150-msquares. It is shown that this technique may be useful both in describinggang activity areas and in describing the spatial distribution of crime inlarge cities. A strong relationship is found between the number of gangsthat are active in an area and the general level of criminal activity.     

Predictive crime mapping

Geographic Information Systems (GIS) have emerged as a key tool in intelligence-led policing and spatial predictions of crime are being used by many police services to reduce crime. Break and entries (BNEs) are one of the most patterned and predictable crime types, and may be particularly amendable to predictive crime mapping. A pilot project was conducted to spatially predict BNEs and property crime in Vancouver, Canada. Using detailed data collected by the Vancouver Police Department on where and when observed crimes occur, the statistical model was able to predict future BNEs for residential and commercial locations. Ideally implemented within a mobile GIS, the automated model provides continually updated predictive maps and may assist patrol units in self-deployment decisions. Future research is required to overcome computational and statistical limitations, and to preform model validation.     

A New Method for Human ABO Genotyping Using a Universal Reporter Primer System

Abstract: We developed a new method for forensic ABO genotyping based on a universal reporter primer (URP) system. This allows for the simultaneous detection of six single nucleotide polymorphism (SNP) sites in the ABO gene (nucleotide positions 261, 297, 526, 703, 796, and 803). This URP system provides obvious peaks, ranging from 82 to 151 bp in length. ABO genotypes were classified and successfully genotyped by our method, including minor alleles that may cause a discrepancy between the genetic data and serological phenotypes. Full profiles were identified using as little as 0.1 ng (0.05 ng/reaction) of standard K562 and 9947A DNA. Moreover, the success rate of genotyping from a URP system was much higher than that from a conventional primer extension method in degraded DNA. This method enables simple and rapid detection of multiple SNP sites on human ABO genes and is highly specific and sensitive when using limited and degraded DNA.     

法医物证DNA自动化检验技术体系的研究

目的建立自动化工作站同步提取不同种类涉案法医生物检材DNA的新方法。方法选用TECAN Freedom EVO100．4、75—2型自动化提取、加样工作站,采用磁珠法及Chelex-100法对各类涉案生物检材进行DNA提取、PCR扩增、毛细管电泳检测其STR分型,进行比较测试。在“全国公安机关DNA数据库应用系统”中建立并应用实验室信息管理系统（LIMS）模拟实施规范化DNA检案。结果1552份各类检材,采用工作站-磁珠法提取DNA效果最佳,STR检测成功率为95％,工作站-Chelex法为88％;二者分别与其手工提取法比较,成功率无明显差异。92个样本同期检测,自动化工作站较手工操作DNA检案时间可缩减1．25倍。结论工作站域珠法提取涉案检材DNA,可获得满意的STR分型结果。应用LIMS管控,可有效防控污染,明显提高检案效率及鉴定质量。     

期货投资的VaR模型及实证分析——以上海期铜15年历史数据为例

VaR模型作为测量金融风险度的标尺,可用以期货投资的风险测度.根据上海期铜过去15年的历史数据,分别运用静态VaR模型、GARCH(1,1)模型和EⅥ'模型来测量其VaR水平,并在此基础上对这些模型的测量结果进行检验和比较,结果表明:静态VaR模型并不能有效地测度风险,而GARCH(1,1)模型和EvT模型的结合则可以较好地控制风险.     

纤维连接蛋白在诊断心肌梗死的特异性研究

探讨纤维连接蛋白 (Fn)对心肌梗死死后诊断的特异性。应用免疫组织化学和图像分析技术 ,对正常心脏、心肌梗死及其它非梗死性因素 ,如心肌炎、窒息、电击死、出血性休克、心挫伤、有机磷中毒等 ,直接或间接引起心脏损害时心肌细胞内Fn的变化进行研究。结果发现 :Fn仅在心肌梗死与心肌炎病例出现阳性反应 ,其阳性反应面积同正常对照组存在显著性差异 ,在窒息、电击死、出血性休克、心挫伤、有机磷中毒等病例未见明显阳性反应。Fn作为心肌梗死死后诊断指标仅受心肌炎的影响 ,对诊断心肌梗死具有较好的特异性     

Decision support for using mobile Rapid DNA analysis at the crime scene

Mobile Rapid DNA technology is close to being incorporated into crime scene investigations, with the potential to identify a perpetrator within hours. However, the use of these techniques entails the risk of losing the sample and potential evidence, because the device not only consumes the inserted sample, it is also is less sensitive than traditional technologies used in forensic laboratories. Scene of Crime Officers (SoCOs) therefore will face a ‘time/success rate trade-off’ issue when making a decision to apply this technology.In this study we designed and experimentally tested a Decision Support System (DSS) for the use of Rapid DNA technologies based on Rational Decision Theory (RDT). In a vignette study, where SoCOs had to decide on the use of a Rapid DNA analysis device, participating SoCOs were assigned to either the control group (making decisions under standard conditions), the Success Rate (SR) group (making decisions with additional information on DNA success rates of traces), or the DSS group (making decisions supported by introduction to RDT, including information on DNA success rates of traces).This study provides positive evidence that a systematic approach for decision-making on using Rapid DNA analysis assists SoCOs in the decision to use the rapid device. The results demonstrated that participants using a DSS made different and more transparent decisions on the use of Rapid DNA analysis when different case characteristics were explicitly considered. In the DSS group the decision to apply Rapid DNA analysis was influenced by the factors “time pressure” and “trace characteristics” like DNA success rates. In the SR group, the decisions depended solely on the trace characteristics and in the control group the decisions did not show any systematic differences on crime type or trace characteristic.Guiding complex decisions on the use of Rapid DNA analyses with a DSS could be an important step towards the use of these devices at the crime scene.     

Trace Elemental Analysis of Titanium Dioxide Pigments and Automotive White Paint Fragments for Forensic Examination Using High‐Energy Synchrotron Radiation X‐Ray Fluorescence Spectrometry*

Abstract: High‐energy synchrotron radiation x‐ray fluorescence spectrometry (SR‐XRF) utilizing 116 keV x‐rays was used to characterize titanium dioxide pigments (rutile) and automotive white paint fragments for forensic examination. The technique allowed analysis of K lines of 9 trace elements in 18 titanium dioxide pigments (rutile), and 10 trace elements in finish coat layers of seven automotive white paint fragments. High‐field strength elements (HFSE) were found to strongly reflect the origin of the titanium dioxide (TiO₂) pigments, and could be used as effective parameters for discrimination and classification of the pigments and paint fragments. A pairwise comparison of the finish coat layers of seven automotive white paint fragments was performed. The trace elements in the finish coat layers detected by the high‐energy SR‐XRF were especially effective for identification. By introducing the trace element information of primer and electrocoat layers, all the automotive white paint fragments could be discriminated by this technique.