A GENERATIVE MODEL OF OFFENDERS' SPATIAL BEHAVIOUR

2011 ◽  
Vol 19 (05) ◽  
pp. 825-842 ◽  
Author(s):  
RICHARD BACHE ◽  
FABIO CRESTANI
Keyword(s):  
Generative Models ◽  
Spatial Behaviour ◽  
Decay Function ◽  
Basic Model ◽  
Preferred Direction ◽  
Police Data ◽  
Other Information ◽  
Functional Forms ◽  
Negative Exponential ◽  
The Relationship

The relationship between distance travelled to an offence and frequency of offending has traditionally been expressed as a (downward-sloping) decay function and such a curve is typically used to fit empirical data. It is proposed here that a decay function should be viewed as a probability density function. It is then possible to construct generative models to assign probabilities to suspects from a set of known offenders whose past crimes are stored in a police data archive. Probabilities can then be used to prioritise suspects in an investigation and calculate the probability of being the culprit. Two functional forms of the decay function are considered: negative exponential and power. These are shown empirically to outperform a basic model which simply ranks suspects by distance from the crime. The model is then extended to include also preferred direction of travel which varies between offenders. If direction of travel is incorporated then predictions become more accurate. The generative decay model has two advantages over a basic model. Firstly it can incorporate other information such as past frequency of offending. Secondly, it provides an estimate of suspect likelihood indicating the trustworthiness of any inference by the model.

Tenses in 19th-century Dutch sentence-grammar

1988 ◽  
Vol 15 (1-2) ◽  
pp. 187-205
Author(s):  
J. A. Le Loux-Schuringa
Keyword(s):  
The Netherlands ◽  
19Th Century ◽  
Morphological Form ◽  
Other Information ◽  
Dutch Language ◽  
One To One ◽  
The 19Th Century ◽  
The Relationship

Summary In this paper some theories on tenses are described. These theories appeared in the Netherlands in the first half of the 19th century. The purpose is not just describing the different tense-systems of P. Weiland (1805), W. Bilderdijk (1826), W. G. Brill (1846) and L. A. te Winkel (1866). In the first half of the 19th century some fundamental changes took place. It is shown that these changes are based upon continuity of research of time and tense in the Dutch tradition. This continuity is found on three levels: (a) The research was concentrated on the verbal forms, no other information from the sentence was used. (b) The grammarians took the relationship between linguistic forms and logical categories as a one-to-one relation. (c) The morphological form of the Dutch language determined the grammatical representation of the tense-systems more and more.

scholarly journals Curriculum Learning for Natural Answer Generation

2018 ◽  
Author(s):  
Cao Liu ◽  
Shizhu He ◽  
Kang Liu ◽  
Jun Zhao
Keyword(s):  
Full Advantage ◽  
Real World ◽  
Large Scale ◽  
Question Answering ◽  
Generative Models ◽  
The Internet ◽  
Basic Model ◽  
The Arts ◽  
Learning Data

By reason of being able to obtain natural language responses, natural answers are more favored in real-world Question Answering (QA) systems. Generative models learn to automatically generate natural answers from large-scale question answer pairs (QA-pairs). However, they are suffering from the uncontrollable and uneven quality of QA-pairs crawled from the Internet. To address this problem, we propose a curriculum learning based framework for natural answer generation (CL-NAG), which is able to take full advantage of the valuable learning data from a noisy and uneven-quality corpus. Specifically, we employ two practical measures to automatically measure the quality (complexity) of QA-pairs. Based on the measurements, CL-NAG firstly utilizes simple and low-quality QA-pairs to learn a basic model, and then gradually learns to produce better answers with richer contents and more complete syntaxes based on more complex and higher-quality QA-pairs. In this way, all valuable information in the noisy and uneven-quality corpus could be fully exploited. Experiments demonstrate that CL-NAG outperforms the state-of-the-arts, which increases 6.8% and 8.7% in the accuracy for simple and complex questions, respectively.

scholarly journals Measuring the Destination Accessibility of Cycling Transfer Trips in Metro Station Areas: A Big Data Approach

2019 ◽  
Vol 16 (15) ◽  
pp. 2641 ◽  
Author(s):  
Xueying Wu ◽  
Yi Lu ◽  
Yaoyu Lin ◽  
Yiyang Yang
Keyword(s):  
Positive Association ◽  
Distance Decay ◽  
Decay Function ◽  
Metro Station ◽  
Negative Exponential Function ◽  
Transfer Mode ◽  
Last Mile ◽  
Trip Distance ◽  
Using Data ◽  
Negative Exponential

Cycling is a green, sustainable, and healthy choice for transportation that has been widely advocated worldwide in recent years. It can also encourage the use of public transit by solving the “last-mile” issue, because transit passengers can cycle to and from transit stations to achieve a combination of speed and flexibility. Cycling as a transfer mode has been shown to be affected by various built environment characteristics, such as the urban density, land-use mix, and destination accessibility, that is, the ease with which cyclists can reach their destinations. However, cycling destination accessibility is loosely defined in the literature and the methods of assessing cycling accessibility is often assumed to be equivalent to walking accessibility using the same decay curves, such as the negative exponential function, which ignores the competitive relationship between cycling and walking within a short distance range around transit stations. In this study, we aim to fill the above gap by measuring the cycling destination accessibility of metro station areas using data from more than three million bicycle-metro transfer trips from a dockless bicycle-sharing program in Shenzhen, China. We found that the frequency of bicycle-metro trips has a positive association with a trip distance of 500 m or less and a negative association with a trip distance beyond 500 m. A new cycling accessibility metric with a lognormal distribution decay curve was developed by considering the distance decay characteristics and cycling’s competition with walking. The new accessibility model outperformed the traditional model with an exponential decay function, or that without a distance decay function, in predicting the frequency of bicycle-metro trips. Hence, to promote bicycle-metro integration, urban planners and government agencies should carefully consider the destination accessibility of metro station areas.

Larval fish diversity on the Scotian Shelf

2000 ◽  
Vol 57 (9) ◽  
pp. 1747-1760 ◽  
Author(s):  
N L Shackell ◽  
K T Frank
Keyword(s):  
Larval Fish ◽  
Diversity Indices ◽  
Fish Diversity ◽  
Calanoid Copepods ◽  
Scotian Shelf ◽  
Genus Richness ◽  
Using Data ◽  
Negative Exponential ◽  
Number Of Individuals ◽  
The Relationship

We examined larval fish diversity on the Scotian Shelf using data, representing 91 genera, collected during the Scotian Shelf Ichthyoplankton Program from 1978 to 1982. Two diversity indices (genus richness (GR) and Shannon's entropy (H)) were relatively lower from December to February-March and relatively higher and stable from April to September-October. Taxon composition changed seasonally. Total median log abundance (log10(number of individuals + 1)·1000 m-3) was low from December to February, increased in March, was stable from April to June, and declined from July to October. Our results suggest that the abundance trends of most taxa were not coincident with either a spring or fall bloom of calanoid copepods. Log GR was significantly positively related to H (r = 0.62, p < 0.001, n = 1853). A negative exponential best described the relationship between log GR and log abundance (R2 = 0.77; log GR = 1.37(1 – e-(1.13)(log abundance)), p < 0.001, n = 2357). Shannon's H was not related to log abundance in winter or in summer-fall and was negatively correlated in spring-summer (r = -0.12, p = 0.003, n = 593). Thus, diversity increases with abundance but the composition is dominated by relatively fewer genera at higher levels of abundance. Western - Sable Island banks had higher levels of GR and abundance in all seasons. Additional banks were diverse and productive during warmer months.

scholarly journals AMBIGUITIES IN DETERMINATION OF SELF-AFFINITY IN THE AE-INDEX TIME SERIES

Fractals ◽  
2001 ◽  
Vol 09 (04) ◽  
pp. 471-479 ◽  
Author(s):  
N. W. WATKINS ◽  
M. P. FREEMAN ◽  
C. S. RHODES ◽  
G. ROWLANDS
Keyword(s):  
Time Series ◽  
Dynamic Range ◽  
Solar Wind Plasma ◽  
Linear Scaling ◽  
Ae Index ◽  
Other Information ◽  
Confinement System ◽  
Dilation Factor ◽  
Functional Forms

The interaction between the Earth's magnetic field and the solar wind plasma results in a natural plasma confinement system which stores energy. Dissipation of this energy through Joule heating in the ionosphere can be studied via the Auroral Electrojet (AE) index. The apparent broken power law form of the frequency spectrum of this index has motivated investigation of whether it can be described as fractal coloured noise. One frequently-applied test for self-affinity is to demonstrate linear scaling of the logarithm of the structure function of a time series with the logarithm of the dilation factor λ. We point out that, while this is conclusive when applied to signals that are self-affine over many decades in λ, such as Brownian motion, the slope deviates from exact linearity and the conclusions become ambiguous when the test is used over shorter ranges of λ. We demonstrate that non self-affine time series made up of random pulses can show near-linear scaling over a finite dynamic range such that they could be misinterpreted as being self-affine. In particular, we show that pulses with functional forms such as those identified by Weimer within the AL index, from which AE is partly derived, will exhibit nearly linear scaling over ranges similar to those previously shown for AE and AL. The value of the slope, related to the Hurst exponent for a self-affine fractal, seems to be a more robust discriminator for fractality, if other information is available.

Seed mass and early survivorship of tree species in upland clearings and shelterwoods

1998 ◽  
Vol 28 (9) ◽  
pp. 1307-1316 ◽  
Author(s):  
D F Greene ◽  
E A Johnson
Keyword(s):  
Leaf Litter ◽  
Power Law ◽  
Tree Species ◽  
Picea Glauca ◽  
Mineral Soil ◽  
Seed Mass ◽  
High Survivorship ◽  
Small Seed ◽  
Negative Exponential ◽  
The Relationship

We examined recommended sowing densities of 25 North American tree species (26 observations) to measure the relationship between juvenile survivorship and seed mass in large clearings and shelterwoods. Two models for expressing the relationship (simple power law or a cumulative negative exponential adjusted to account for rodent-repellent application and seedbed type) all showed that survivorship is highly dependent on seed mass. For a small seed, mineral soil and thin humus confer roughly equally high survivorship. Leaf litter is very poor, and undisturbed thick moss appears to be the worst possible organic seedbed on upland sites. An examination of 30 records of Picea glauca (Moench) Voss survivorship (3- to 6-year-old cohorts) on mineral soil revealed substantial intraspecific variation with only 50% of the values within twofold of the predicted value.

Microwedge Machining for the Manufacture of Directional Dry Adhesives

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Paul Day ◽  
Eric V. Eason ◽  
Noe Esparza ◽  
David Christensen ◽  
Mark Cutkosky
Keyword(s):  
Flat Glass ◽  
Shear Loading ◽  
Mold Material ◽  
Preferred Direction ◽  
Process Characterization ◽  
Feature Geometry ◽  
Dry Adhesives ◽  
Tool Trajectory ◽  
Normal Adhesion ◽  
The Relationship

Directional dry adhesives are inspired by animals such as geckos and are a particularly useful technology for climbing applications. Previously, they have generally been manufactured using photolithographic processes. This paper presents a micromachining process that involves making cuts in a soft material using a sharp, lubricated tool to create closely spaced negative cavities of a desired shape. The machined material becomes a mold into which an elastomer is cast to create the directional adhesive. The trajectory of the tool can be varied to avoid plastic flow of the mold material that may adversely affect adjacent cavities. The relationship between tool trajectory and resulting cavity shape is established through modeling and process characterization experiments. This micromachining process is much less expensive than previous photolithographic processes used to create similar features and allows greater flexibility with respect to the microscale feature geometry, mold size, and mold material. The micromachining process produces controllable, directional adhesives, where the normal adhesion increases with shear loading in a preferred direction. This is verified by multi-axis force testing on a flat glass substrate. Upon application of a post-treatment to decrease the roughness of the engaging surfaces of the features after casting, the adhesives significantly outperform comparable directional adhesives made from a photolithographic mold.

scholarly journals Influence of Inoculum Density of Verticillium dahliae on Root Discoloration of Horseradish

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 309-315 ◽  
Author(s):  
A. Khan ◽  
N. Atibalentja ◽  
D. M. Eastburn
Keyword(s):  
Verticillium Dahliae ◽  
Commercial Production ◽  
Inoculum Density ◽  
Forecast System ◽  
Factors Affecting ◽  
Initial Inoculum ◽  
Disease Forecast ◽  
Low Levels ◽  
Negative Exponential ◽  
The Relationship

The relationship between inoculum density (number of microsclerotia per gram of air-dried soil) of Verticillium dahliae at the time of planting and the severity and incidence of root discoloration of horseradish at harvest was investigated in a 2-year study conducted in the greenhouse, microplots, and commercial production fields. The objective of the study was to develop a disease-forecast system that would assist growers in assessing the risk of the disease before planting horseradish in a particular field. Significant correlations were observed between inoculum density and severity and incidence of root discoloration in the greenhouse and microplots, although the form of the relationship varied with trials from linear to quadratic and negative exponential. No correlation was found between inoculum density of V. dahliae and severity and incidence of root discoloration in commercial production fields. In some fields with low inoculum densities, high ratings of severity and incidence of root discoloration were observed even with the partially resistant cultivar 769A. Conversely, in other fields with high inoculum densities, low ratings of severity and incidence of discolored roots were observed even with the susceptible cultivar 647A. These results suggest that a disease-forecast system based solely on inoculum densities of V. dahliae would be unreliable under field conditions when the other factors affecting the inoculum density-disease relationships cannot be controlled. Knowing the amount of initial inoculum may, however, save growers from planting horseradish in highly infested fields, but it would not guarantee a disease-free crop in fields with low levels of infestation.

Human Geography, Regional Science, and the Study of Individual Behaviour

1976 ◽  
Vol 8 (4) ◽  
pp. 397-409 ◽  
Author(s):  
I G Cullen
Keyword(s):  
Hypothesis Testing ◽  
Philosophy Of Science ◽  
Problem Formulation ◽  
Human Geography ◽  
Natural Sciences ◽  
Regional Science ◽  
Spatial Behaviour ◽  
Individual Behaviour ◽  
Behavioural Research ◽  
The Relationship

This paper discusses the relationship between the highly disaggregated studies of spatial behaviour and perception, which are becoming more and more commonplace in the geographic and planning literature, and the basic tenets of the methods generally accepted within the parent disciplines of human geography and regional science. The argument is advanced that the relationship is an unfortunate one of dependence; that behavioural research in geography has accepted too easily a philosophy of science and an approach to problem formulation and hypothesis testing which is ‘handed down’ indirectly from the natural sciences; and that this limitation has effectively precluded a whole range of approaches to the study of human spatial behaviour, approaches which could be very fruitful indeed.

An Approach to Modeling Crustacean Egg-Bearing Fractions as a Function of Size and Season

1991 ◽  
Vol 48 (8) ◽  
pp. 1431-1436 ◽  
Author(s):  
Victor R. Restrepo ◽  
Reg A. Watson
Keyword(s):  
Egg Production ◽  
Logistic Function ◽  
Parameter Estimates ◽  
Seasonal Trends ◽  
Basic Model ◽  
Maximum Likelihood Methods ◽  
Temperature Parameter ◽  
Gravid Females ◽  
The Individual ◽  
The Relationship

We present an approach to the analysis of crustacean egg production ogives with emphasis on detecting seasonal trends. The relationship between the proportion of gravid females (by size) and season is a prerequisite to the estimation of egg production potentials of populations. The basic method consists of relating, for each sample, the proportion of berried females with their size through a three-parameter logistic function where the asymptote may be less than 1. We then provide guidance for detecting seasonal trends in the estimates of the parameters for the individual samples. This is accomplished by restricting the basic model such that some parameters are considered to be either fixed for all samples or as simple functions of time or environmental variables such as temperature. Parameter estimates are obtained via maximum likelihood methods, and comparisons between alternative models are presented graphically and using likelihood ratio tests. We illustrate the approach and its application with data for a tropical shrimp, Penaeus esculentus, from northern Australia.

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