Bayesian Journey-to-Crime Estimation: An Improvement in Geographic Profiling Methodology     

Ned Levine  Richard Block 《The Professional geographer》2013,65(2):213-229

A Bayesian approach to geographic profiling methodology involves updating journey-to-crime probability estimates with probabilities based on the distribution of residences of other offenders who committed crimes in the same locations. Tests were conducted on serial offenders from Baltimore County and Chicago and six different methods using five different criteria were compared. The Bayesian method was more accurate than the existing journey-to-crime methods and was as accurate as the center of minimum distance, the current best method. Suggestions for improving the methodology further are provided.  相似文献   

Sources of uncertainty in estimating stream solute export from headwater catchments at three sites          下载免费PDF全文

Ruth D. Yanai  Naoko Tokuchi  John L. Campbell  Mark B. Green  Eiji Matsuzaki  Stephanie N. Laseter  Cindi L. Brown  Amey S. Bailey  Pilar Lyons  Carrie R. Levine  Donald C. Buso  Gene E. Likens  Jennifer D. Knoepp  Keitaro Fukushima 《水文研究》2015,29(7):1793-1805

Uncertainty in the estimation of hydrologic export of solutes has never been fully evaluated at the scale of a small‐watershed ecosystem. We used data from the Gomadansan Experimental Forest, Japan, Hubbard Brook Experimental Forest, USA, and Coweeta Hydrologic Laboratory, USA, to evaluate many sources of uncertainty, including the precision and accuracy of measurements, selection of models, and spatial and temporal variation. Uncertainty in the analysis of stream chemistry samples was generally small but could be large in relative terms for solutes near detection limits, as is common for ammonium and phosphate in forested catchments. Instantaneous flow deviated from the theoretical curve relating height to discharge by up to 10% at Hubbard Brook, but the resulting corrections to the theoretical curve generally amounted to <0.5% of annual flows. Calibrations were limited to low flows; uncertainties at high flows were not evaluated because of the difficulties in performing calibrations during events. However, high flows likely contribute more uncertainty to annual flows because of the greater volume of water that is exported during these events. Uncertainty in catchment area was as much as 5%, based on a comparison of digital elevation maps with ground surveys. Three different interpolation methods are used at the three sites to combine periodic chemistry samples with streamflow to calculate fluxes. The three methods differed by <5% in annual export calculations for calcium, but up to 12% for nitrate exports, when applied to a stream at Hubbard Brook for 1997–2008; nitrate has higher weekly variation at this site. Natural variation was larger than most other sources of uncertainty. Specifically, coefficients of variation across streams or across years, within site, for runoff and weighted annual concentrations of calcium, magnesium, potassium, sodium, sulphate, chloride, and silicate ranged from 5 to 50% and were even higher for nitrate. Uncertainty analysis can be used to guide efforts to improve confidence in estimated stream fluxes and also to optimize design of monitoring programmes. © 2014 The Authors. Hydrological Processes published John Wiley & Sons, Ltd.  相似文献   

Stable oxygen and carbon isotope profiles in an invasive bivalve (Corbicula fluminea) in North Carolina watersheds     

John P. Bucci  William J. Showers  Jay F. Levine 《Geochimica et cosmochimica acta》2009,73(11):3234-3247

The modern invasive bivalve Corbicula fluminea was collected in 2006 from three sites with different land uses located in a North Carolina River Basin. The primary objective was to describe the δ¹⁸O and δ¹³C profiles of C. fluminea shells under various land use conditions. An additional aim was to evaluate whether growth patterns of C. fluminea form seasonally. Annual shell growth patterns were measured from the umbo to the margin and co-varied with estimates of ambient water temperature, corresponding to seasonal variation. The C. fluminea growth patterns as translucent bands (slower growth) appeared to form during winter months and opaque bands (rapid growth) formed during summer. A mixed model analysis (ANOVA) showed a significant site level effect of δ¹⁸O and δ¹³C profiles examined among sites (F = 17.1; p = 0.003). A second model showed a borderline significant site effect among profiles with variability more pronounced at the urban site, Crabtree Creek (p = 0.085). Previous habitat assessment ratings and water chemistry measurements suggested that the urban site was more impacted by storm water runoff. Understanding δ¹⁸O and δ¹³C_SHELL profiles and shell growth patterns of the invasive bivalve (C. fluminea) may help establish a framework for using these animals as biomonitors to record water temperature and nutrient pollution.  相似文献   

Strain-tide spectroscopy     

Judah Levine 《Geophysical Journal International》1978,54(1):27-41

Summary. We have used two years of strain-tide data to study the response of the Earth to the diurnal and semidiurnal tidal excitations. Our results show that there is significant structure in the response of the Earth to tidal excitations near one cycle/sidereal day. This structure agrees with the resonance behaviour predicted from calculations of the forced elastic-gravitational response of an elliptical, rotating earth with a liquid outer core. The data can also be used to test for possible preferred frames and spatial anisotropies. We find that upper bounds on the parameterized post-Newtonian (PPN) parameters which characterize these effects are α₂≤ 0.007 and ζ_w≤ 0.005. We also infer that there is a significant frequency dependence to the ocean load near one cycle/day and that the coherence between strain and barometric pressure fluctuations are significant at periods longer than a few days.  相似文献   

Possible high-mobility LAGEOS ranging station     

P.L. Bender  J.E. Faller  J. Levine  S. Moody  M.R. Pearlman  B.C. Silverberg 《Tectonophysics》1979,52(1-4)

A relatively low-cost system for determining both the vertical and horizontal coordinates of several dozen points per year with an accuracy of about 2 cm appears feasible. One approach considered is to use a subnanosecond pulse length laser with a few millijoules per pulse output energy and to employ single photoelectron detection of the returned signal. The single photoelectron approach has been thoroughly tested in the Lunar Laser Ranging Experiment. With a laser average power of about 50 mW, a 30-cm diameter transmit-receive aperture, 10 arc sec pointing accuracy and a beam divergence of 20 arc sec, the expected returned signal level is about 70 pulses in a 3-min interval. If the differences between the observed ranges and those calculated from a reasonably good LAGEOS ephemeris over a 3-min interval are considered, the expected standard deviation of the mean is < 0.7 cm.The calibration procedure used in lunar ranging appears capable of reducing any bias due to the photomultiplier or timing system to 0.5 cm. The other main error source we have considered for the measured optical transit time is a possible difference in arrival time in different parts of the far field pattern because of laser mode structure. This effect needs to be checked experimentally, but we expect it to be 0.5 cm or less for a laser pulse length of about 200 psec. Based on these error estimates, simulations for one week of observations from the high-mobility station have been carried out for us at the National Geodetic Survey. When a refraction model error of 0.15% was used, the uncertainty of the high-mobility station position with respect to a reference station 500 km away was found to be 2.4 cm or less in each coordinate. After the gravity-field uncertainties have been reduced, the station location accuracy will be improved further and the limitation of measuring with respect to a regional reference station can be relaxed.  相似文献   

Seismic response evaluation of Meloland Road Overpass using 1979 imperial Valley earthquake records     

S. D. Werner  J. L. Beck  M. B. Levine 《地震工程与结构动力学》1987,15(2):249-274

During the 1979 Imperial Valley earthquake, an array of 26 strong-motion accelerometers produced records for the Meloland Road Overpass, a two-span reinforced concrete bridge structure located only 0.5 km away from the causative fault for this earthquake event. This paper describes the application of a new system identification methodology to the array of strong-motion measurements, in order to assess seismic response characteristics of this bridge. Results of this application show that (1) linear models provide an excellent fit to the measured motions of the bridge, despite the fact that it was subjected to very strong shaking; (2) the transverse response of the structure is controlled by its abutment motions, with no significant dynamic amplification in the deck; and (3) the vertical response of the bridge deck at the midlength of its spans is dominated by a single vertical translational mode whereas, above the central pier, the deck's vertical response is most affected by the vertical motions of the pier base and by torsion of the deck. Also, systematic estimates of modal damping ratios and qualitative assessments of states of stress developed in the bridge during the earthquake are provided.  相似文献   

Determining geologic sources of artifact copper: Source characterization using trace element patterns     

Mary Ann Levine 《Geoarchaeology》2002,17(6):625-627

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Finding a “Disappearing” Nontimber Forest Resource: Using Grounded Visualization to Explore Urbanization Impacts on Sweetgrass Basketmaking in Greater Mt. Pleasant,South Carolina∗     

Patrick T. Hurley  Angela C. Halfacre  Norm S. Levine  Marianne K. Burke 《The Professional geographer》2013,65(4):556-578

Despite growing interest in urbanization and its social and ecological impacts on formerly rural areas, empirical research remains limited. Extant studies largely focus either on issues of social exclusion and enclosure or ecological change. This article uses the case of sweetgrass basketmaking in Mt. Pleasant, South Carolina, to explore the implications of urbanization, including gentrification, for the distribution and accessibility of sweetgrass, an economically important nontimber forest product (NTFP) for historically African American communities, in this rapidly growing area. We explore the usefulness of grounded visualization for research efforts that are examining the existence of “fringe ecologies” associated with NTFP. Our findings highlight the importance of integrated qualitative and quantitative analyses for revealing the complex social and ecological changes that accompany both urbanization and rural gentrification.  相似文献   

Decade time-scale modulation of low-mass X-ray binaries     

Martin Durant  Remon Cornelisse  Ron Remillard  Alan Levine 《Monthly notices of the Royal Astronomical Society》2010,401(1):355-361

Regular observations by the All-Sky Monitor aboard the Rossi X-ray Timing Explorer satellite have yielded well-sampled light curves with a time baseline of over 10 years. We find that up to eight of the 16 brightest persistent low-mass X-ray binaries (LMXBs) show significant, possible sinusoidal, variations with periods of the order of 10 years. We speculate on its possible origin and prevalence in the population of LMXBs, and we find the presence of a third object in the system, or long-period variability intrinsic to the donor star, as being attractive origins for the X-ray flux modulation we detect. For some of the objects in which we do not detect a signal, there is substantial short-term variation which may hide modest modulation on long time-scales. Decade time-scale modulations may thus be even more common.  相似文献   

Elastic properties of double-porosity rocks using the differential effective medium model     

M. Markov  V. Levine  A. Mousatov  E. Kazatchenko 《Geophysical Prospecting》2005,53(5):733-754

An approach to determining the effective elastic moduli of rocks with double porosity is presented. The double‐porosity medium is considered to be a heterogeneous material composed of a homogeneous matrix with primary pores and inclusions that represent secondary pores. Fluid flows in the primary‐pore system and between primary and secondary pores are neglected because of the low permeability of the primary porosity. The prediction of the effective elastic moduli consists of two steps. Firstly, we calculate the effective elastic properties of the matrix with the primary small‐scale pores (matrix homogenization). The porous matrix is then treated as a homogeneous isotropic host in which the large‐scale secondary pores are embedded. To calculate the effective elastic moduli at each step, we use the differential effective medium (DEM) approach. The constituents of this composite medium – primary pores and secondary pores – are approximated by ellipsoidal or spheroidal inclusions with corresponding aspect ratios. We have applied this technique in order to compute the effective elastic properties for a model with randomly orientated inclusions (an isotropic medium) and aligned inclusions (a transversely isotropic medium). Using the special tensor basis, the solution of the one‐particle problem with transversely isotropic host was obtained in explicit form. The direct application of the DEM method for fluid‐saturated pores does not account for fluid displacement in pore systems, and corresponds to a model with isolated pores or the high‐frequency range of acoustic waves. For the interconnected secondary pores, we have calculated the elastic moduli for the dry inclusions and then applied Gassmann's tensor relationships. The simulation of the effective elastic characteristic demonstrated that the fluid flow between the connected secondary pores has a significant influence only in porous rocks containing cracks (flattened ellipsoids). For pore shapes that are close to spherical, the relative difference between the elastic velocities determined by the DEM method and by the DEM method with Gassmann's corrections does not exceed 2%. Examples of the calculation of elastic moduli for water‐saturated dolomite with both isolated and interconnected secondary pores are presented. The simulations were verified by comparison with published experimental data.  相似文献