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1.
This paper reports the results of an empirical comparison of various types of competing risk models in predicting the timing
and duration of activities. In particular, three types of models are compared: a non-competing risk model, an unconditional
competing risk model, and a conditional competing risk model. The models are applied to an activity diary, collected in the
Netherlands. The results of the comparison indicate that the conditional competing risk model performs best, indicating that
the choice and timing of activities depends on the nature and duration of the activity conducted previously. The specific
structure of these dependent transition probabilities are discussed in detail. Several socio-demographic variables are found
to be significantly related to the transition probabilities.
Received: 19 July 2001 / Accepted: 25 January 2002 相似文献
2.
Combining the geodetic models of vertical crustal deformation 总被引：6，自引：0，他引：6
Different kinds of analytical models of vertical curstal deformation have both advantages and disadvantages, and are appropriate
to different deformation patterns. It is difficult to identify which deformation model is most suitable for a particular deformation
area. In order to obtain a more precise and reliable analytical result, the combined model based on forecast theory has been
approached. As a result, the fitting ability of single models is significantly improved. The combined model still possesses
the same important features as the single models, which enable transferal of the derived crustal deformation information,
within or even outside the time span of the data coverage, from geodetic sites to any user-specified locations where geodetic
data may not exist. Examples are presented of both numerical simulation and a real-life situation, and the results are analysed
in detail to demonstrate the efficiency of the proposed methodology.
Received: 26 January 1998 / Accepted 14 August 1998 相似文献
3.
Eric J.E. Molin Harmen Oppewal Harry J.P. Timmermans 《Journal of Geographical Systems》2002,4(4):343-358
In this paper, two approaches for measuring residential group preferences, based on the method of Hierarchical Information
Integration (HII), are compared. In particular, the hypothesis that group-based preference models estimated from integrated
HII experiments better predict group preferences than part individual-based group models estimated from classical HII experiments
is tested. To that effect, the models' ability to predict group preferences for new residential alternatives is compared in
a study of residential preferences of co-ops. Results indicate that integrated HII group experiments indeed result in better
predictions of residential preferences. 相似文献
4.
B. Fong Chao 《Journal of Geodesy》1961,59(1):81-93
The numerical prediction of the Earth’s polar motion is of both theoretical and practical interest. The present paper is aimed
at a comprehensive, experimental study of the predictability of polar motion using a homogeneous BIH (Bureau International
de l’Heure) data set for the period 1967–1983. Based on our knowledge of the physics of the annual and the Chandler wobbles,
we build the numerical model for the polar motion by allowing the wobble period to vary. Using an optimum base length of six
years for prediction, this “floating-period” model, equipped with a nonlinear least-squares estimator, is found to yield polar
motion predictions accurate to within 0″.012 to 0″.024 depending on the prediction length up to one year, corresponding to
a predictability of 89–82%. This represents a considerable improvement over the conventional fixed-period predictor, which,
by its nature, does not respond to variations in the apparent wobble periods (in particular, a dramatic decrease in the periods
of both the annual and the Chandler wobbles after the year 1980). The superiority of the floating-period predictor to other
predictors based on critically different numerical models is also demonstrated. 相似文献
5.
Deriving rules from activity diary data: A learning algorithm and results of computer experiments 总被引：1，自引：0，他引：1
Theo A. Arentze Frank Hofman Harry J.P. Timmermans 《Journal of Geographical Systems》2001,3(4):325-346
Activity-based models consider travel as a derived demand from the activities households need to conduct in space and time.
Over the last 15 years, computational or rule-based models of activity scheduling have gained increasing interest in time-geography
and transportation research. This paper argues that a lack of techniques for deriving rules from empirical data hinders the
further development of rule-based systems in this area. To overcome this problem, this paper develops and tests an algorithm
for inductively deriving rules from activity-diary data. The decision table formalism is used to exhaustively represent the
theoretically possible decision rules that individuals may use in sequencing a given set of activities. Actual activity patterns
of individuals are supplied to the system as examples. In an incremental learning process, the system progressively improves
on the selection of rules used for reproducing the examples. Computer experiments based on simulated data are performed to
fine-tune rule selection and rule value update functions. The results suggest that the system is effective and fairly robust
for parameter settings. It is concluded, therefore, that the proposed approach opens up possibilities to derive empirically
tested rule-based models of activity scheduling. Follow-up research will be concerned with testing the system on empirical
data.
Received: 31 January 2001 / Accepted: 13 September 2001 相似文献
6.
This paper analyzes the spatial patterns of households' distribution in clusters of cities and the effects on regional growth
using spatial exploratory techniques and a model of growth that incorporates spatial location. Our empirical analysis shows
that, over the 1980–1990 period, in Southern New England, patterns of spatial clustering of households did create heterogeneous
growth rates in the region. Also, there is evidence that clusters of cities and isolated cities created spillover growth effects
in bordering towns.
Received: 5 September 2001 / Accepted: 2 August 2002 相似文献
7.
Local land‐use and ‐cover changes (LUCCs) are the result of both the decisions and actions of individual land‐users, and the larger global and regional economic, political, cultural, and environmental contexts in which land‐use systems are embedded. However, the dearth of detailed empirical data and knowledge of the influences of global/regional forces on local land‐use decisions is a substantial challenge to formulating multi‐scale agent‐based models (ABMs) of land change. Pattern‐oriented modeling (POM) is a means to cope with such process and parameter uncertainty, and to design process‐based land change models despite a lack of detailed process knowledge or empirical data. POM was applied to a simplified agent‐based model of LUCC to design and test model relationships linking global market influence to agents’ land‐use decisions within an example test site. Results demonstrated that evaluating alternative model parameterizations based on their ability to simultaneously reproduce target patterns led to more realistic land‐use outcomes. This framework is promising as an agent‐based virtual laboratory to test hypotheses of how and under what conditions driving forces of land change differ from a generalized model representation depending on the particular land‐use system and location. 相似文献
8.
Coupling land use allocation models with raster GIS 总被引：5，自引：0，他引：5
As geographic information systems (GIS) have moved from information storage and retrieval operations towards more decision
support functions, there is a need for more integration of spatial analytical modules that can assist in locational decisions.
This paper presents a methodology for coupling land use allocation models with a raster GIS. For raster systems, the integration
of any decision module has been limited by the size of raster datasets that may contain hundreds of thousands of pixels. Therefore,
decision heuristics have been used rather than exact methods such as mathematical programming models. For the problem of land
use allocation, the special structure of the generalized assignment problem is used here to handle large scale datasets. The
advantage of the mathematical programming approach is the additional information associated with the dual variables and opportunity
costs that can be used in subsequent sensitivity analyses.
Received: 7 April 1998/Accepted: 2 October 1998 相似文献
9.
Evaluating the importance of accessibility to congestion response using a GIS-based travel simulator
Irene Casas 《Journal of Geographical Systems》2003,5(1):109-127
This paper examines the effect of accessibility on individual response to unexpected traffic delays and congestion. The dataset
used was collected by means of a travel simulator developed within a geographic information system (GIS) environment. The
simulator models a commute trip where congestion takes place, and subjects are asked to respond by making a choice among alternative
courses of action. Available alternatives for dealing with the unexpected traffic delay include changing the location of the
planned activities or changing the activities to be performed. Accessibility to the new locations and to the different activities
is computed using a cumulative measure. Analysis using CHAID tree technique found that accessibility is a good predictor of
subjects' choice when responding to unexpected traffic delays.
Received: September 2002 / Accepted: January 2003
Support for this research by a grant from the Center of Intelligent Transportation Research of the Ohio State University
is gratefully acknowledged. The author would also like to thank Joe Weber, Mei-Po Kwan and two anonymous reviewers for their
valuable comments. 相似文献
10.
On the design of formal theories of geographic space 总被引：1，自引：0，他引：1
This paper discusses the design of formal theories of geographic space for the application in Geographic Information Systems.
GIS software is an implementation of formal theories of geographic space. The notions of formal theories are introduced and
discussed in the context of examples from the GIS field.
Our approach is an application of the general framework of formal theories to the special class of theories of geographic
space, in particular to the geometry of geographic space. A framework is introduced for characterizing and evaluating formal
theories of geographic space and the process of their design. This is used to provide (1) a classification of formal theories
of geographic space, (2) criteria of their adequacy, and (3) an evaluation of design decisions in the process of formalization.
The paper demonstrates the choices in the design of GIS and the dependencies between these choices. Considering the design
space for theories underlying a GIS, we can see that current GIS are based on one choice: analytical geometry. Other designs
are possible and a systematic exploration of alternative types of GIS, for example, based on constraints or based on stored
spatial relations, becomes necessary.
Received: 30 April 1997/Accepted: 8 March 1999 相似文献
11.
Whereas for commuting travel there is a one-to-one correspondence between commuters and jobs, and for commodity flows a one-to-one
correspondence between the size of orders and the shipping cost of the commodities, the situation is much more complex for
retail/service travel. A typical shopper may make a single trip or multi-stop tour to buy/consume a quite diverse set of commodities/services
at different locations in quite variable quantities. At the same time, the general pattern of the tour is clearly dependent
on the activities and goods available at potential stops. These interdependencies have been alluded to in the literature,
especially by spatial economists. However, until some preliminary work by the first author, there has been no attempt to formally
include these interdependencies in a general model. This paper presents a framework for achieving this goal by developing
an evolutionary set of models starting from the simplest forms available. From the above, it is clear that such interdependency
models will inevitably have high dimensionality and combinatorial complexity. This rules out a simultaneous treatment of all
the events using an individual choice approach. If an individual choice approach is to be applied in a tractable manner, the
set of interdependent events needs to be segmented into several subsets, with simultaneity recognised within each subset,
but a mere sequential progression occurring between subsets. In this paper, full event interdependencies are retained at the
expense of modelling market segments of consumers rather than a sample of representative individuals. We couple the travel
and consumption events in the only feasible way, by modelling the tours as discrete entities, in conjunction with the amount
of each commodity consumed per stop on each such tour in terms of the continuous quantities of microeconomics. This is performed
both under a budget/income constraint from microeconomics and a time budget constraint from time geography. The model considers
both physical trips and tele-orders.
Received: 14 August 2000 / Accepted: 6 October 2001 相似文献
12.
Sprawl measures have largely been neglected in land‐use forecasting models. The current approach for land‐use allocation using optimization mostly utilizes objective functions and constraints that are non‐spatial in nature. Application of spatial constraints could take care of the contiguity and compactness of land uses and can be utilized to address urban sprawl. Because a land‐use model is used as an input to transportation modeling, a better spatial allocation strategy for more compact land‐use projections will promote better transportation planning and sustainable development. This study formulates a scenario‐based approach to normative modeling of urban sprawl. In doing so, it seeks to improve the land‐use projections by employing a spatial optimization model with contiguity and compactness consideration. This study incorporates urban sprawl measures based on smart growth principles together with a mixed‐use factor, and adjacency consideration of nearby land uses. The objective function used in the study maximizes net suitability based on imposed constraints. These constraints are based on smart growth principles that enhance walkability in neighborhoods, promote better health for residents, and encourage mixed‐use development. The formulated model has been applied to Collin County, TX, a fast‐developing suburban county located to the north of the Dallas–Fort Worth metroplex. The suitability of land cells indicates the probability of conversion, which is calculated using spatial discrete choice analysis with Moran eigenvector spatial filtering for vacant cells at a resolution of 150 × 150 m employing factors of the built environment, and socioeconomic and demographic characteristics. This study demonstrates how spatial proximity between land uses, which has been ignored to date, can be used to control sprawl, resulting in better mixing of different land uses based on constraints imposed in a spatial optimization problem. 相似文献
13.
Jean H.P. Paelinck 《Journal of Geographical Systems》2002,4(4):371-383
Links between socio-economic units have been studied by means of various techniques. This study analyses networks that take
on a permanently growing importance in evolutionary economics. The analysis is conducted in a sequential way on matrices picturing
the intensities of certain relations; the technique used is linear assignment. The latter is first applied to matrices of
socio-economic relations set up for the Netherlands and Portugal; the various types of “networking” present could be revealed
and compared. Medical activities, taken in their socio-economic setting, rest also on various networks ; available matrices
for the Netherlands are submitted to the above method of analysis. Moreover, a classical input-output matrix for the United
Kingdom is used as a last test for the validity of the method.
Received: 1 March 2002 / Accepted: 19 November 2002 相似文献
14.
Misspecifications in interaction model distance decay relations: A spatial structure effect 总被引：1，自引：0，他引：1
M. Tiefelsdorf 《Journal of Geographical Systems》2003,5(1):25-50
An exclusively statistical approach is proposed to address the spatial structure effects of general interaction models. It is shown that the spatial heterogeneity in the estimated region-specific distance decay
parameters may in part be due to the combination of two factors: (a) a functional mis-specification of the global distance
decay relationship; and (b) the heterogeneity in the region-specific conditional distance distributions. A properly specified
global distance decay function allows controlling for these spatially induced biases in the local distance decay parameters.
However, inherent multicollinearities between the set of region specific distance decay parameters and other estimated model
parameters prevent an unambiguous interpretation. A key conclusion is that a proper model specification, in particular, the
specification of the global distance decay relationship, is of paramount importance in interaction modeling and for accessibility
studies.
Received: September 2002 / Accepted: January 2003 相似文献
15.
We present a spatial decision support system for the non-profit sector, designed to assist planning in the area of home-delivered
services such as meals on wheels. Using data collected from existing programs, current and forecasted demographic data, and
a set of algorithmic tools, we provide a system for evaluating current meals on wheels facilities, and for making incremental
facility location decisions that satisfy coverage and equity requirements.
Received: 27 September 2000 / Accepted: 22 March 2001 相似文献
16.
Computer networks like the Internet are gaining importance in social and economic life. The accelerating pace of the adoption
of network technologies for business purposes is a rather recent phenomenon. Many applications are still in the early, sometimes
even experimental, phase. Nevertheless, it seems to be certain that networks will change the socioeconomic structures we know
today. This is the background for our special interest in the development of networks, in the role of spatial factors influencing
the formation of networks, and consequences of networks on spatial structures, and in the role of externalities. This paper
discusses a simple economic model – based on a microeconomic calculus – that incorporates the main factors that generate the
growth of computer networks. The paper provides analytic results about the generation of computer networks. The paper discusses
(1) under what conditions economic factors will initiate the process of network formation, (2) the relationship between individual
and social evaluation, and (3) the efficiency of a network that is generated based on economic mechanisms.
Received: 5 July 2000 / Accepted: 28 November 2000 相似文献
17.
An empirical test of the competing destinations model 总被引：2，自引：0，他引：2
It has long been believed that properties of spatial structure have a strong effect on trip distribution, which thus leads
to a bias in the estimated distance decay parameters of spatial interaction models. This paper is an attempt to identify to
what extent the spatial structure effect affects the trip distribution and determine whether the incorporation of a term to
account for the relative location of destinations into the conventional gravity models, results in a model that can more correctly
represent the actual trip distribution. The main focus is on the comparison of the origin–specific estimates of the distance
decay parameter, calibrated from the traditional production-constrained model and the production-constrained competing destinations
model. The results show that the competing destinations model is superior to the conventional model in both reproducing the
interaction flows and giving behavioral explanation to the distance decay parameters, but the essential aim of the competing
destinations model to remove the map pattern from the distance decay parameters of the conventional model has not been identified.
Received: 5 September 2001 / Accepted: 17 June 2002
We are grateful to Gloria. A. Swieczkowski for kindly providing the migration data. The authors also gratefully acknowledge
the comments of the referees. 相似文献
18.
The Spatial Interaction Model proposed by Alonso as “Theory of Movements” offers an innovative specification of spatial origin-destination
flow models. Equations for flows between regions, total outflow from and total inflow to a region are linked by balancing
factors. This paper presents a consistent formulation of Spatial Interaction Models in the Wilson tradition and Alonso's Theory
of Movements. The paper is intended as an introduction to the model and a review of␣the state of the art. Besides it is argued
that simultaneous equation techniques are required to estimate the so-called systemic parameters.
Received: 21 May 2000 / Accepted: 18 January 2001 相似文献
19.
Monitoring of the crustal movements along a tectonic fault is of particular importance in the study of the mechanism of an
earthquake. There are several techniques to gauge crustal deformations, including terrestrial survey methods, space-positioning
techniques and permanently installed geotechnical instruments. Each technique or method has its own advantages and limitations.
Integration of the various techniques into a monitoring scheme is recommended. It is discussed how a proper integrated system
can significantly improve the separability of a monitoring scheme at little additional expense. Separability is the ability
of a monitoring scheme to distinguish among potential deformation models, and can be used for the optimum design of monitoring
schemes. Discussion concentrates on the separability between a dislocation model and a rigid movement model in the area of
an active fault. The addition of a few strain observations to a conventional terrestrial survey scheme can better distinguish
between the above-mentioned models. A simulated example is presented to demonstrate the idea.
Received: 4 November 1997 / Accepted: 9 July 2001 相似文献
20.
Area-based tests for association between spatial patterns 总被引：2，自引：0，他引：2
Edge effects pervade natural systems, and the processes that determine spatial heterogeneity (e.g. physical, geochemical,
biological, ecological factors) occur on diverse spatial scales. Hence, tests for association between spatial patterns should
be unbiased by edge effects and be based on null spatial models that incorporate the spatial heterogeneity characteristic
of real-world systems. This paper develops probabilistic pattern association tests that are appropriate when edge effects
are present, polygon size is heterogeneous, and the number of polygons varies from one classification to another. The tests
are based on the amount of overlap between polygons in each of two partitions. Unweighted and area-weighted versions of the
statistics are developed and verified using scenarios representing both polygon overlap and avoidance at different spatial
scales and for different distributions of polygon sizes. These statistics were applied to Soda Butte Creek, Wyoming, to determine
whether stream microhabitats, such as riffles, pools and glides, can be identified remotely using high spatial resolution
hyperspectral imagery. These new “spatially explicit” techniques provide information and insights that cannot be obtained
from the spectral information alone.
Received 1 June 2001 / Accepted 25 October 2001 相似文献