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1.
Pauline van den Berg Theo Arentze Harry Timmermans 《Journal of Geographical Systems》2012,14(2):125-141
Recently, there has been an increasing interest in the role of social networks in spatial-choice and travel behavior. It has
been acknowledged that social activities and the travel for these activities can emerge from individuals’ social networks
and that social activities are responsible for an important portion of travel demand. The influence of information and communication
technologies (ICT’s) is also important in this respect. The purpose of the paper is to examine the effects of characteristics
of egos and ego-alter relationships on the frequency of social interaction by different communication modes, using multilevel
path analysis. The analyses are based on social network data collected in 2008 in the Eindhoven region in the Netherlands
among 116 respondents. The results indicate a complementary relationship between contact frequencies by different modes. The
contact frequencies of the different modes, especially face-to-face and telephone, can also be largely explained by the ego’s
personal characteristics and the type of relationship and the distance between ego and alter. 相似文献
2.
The total optimal search criterion in solving the mixed integer linear model with GNSS carrier phase observations 总被引：3，自引：2，他引：1
Existing algorithms for GPS ambiguity determination can be classified into three categories, i.e. ambiguity resolution in
the measurement domain, the coordinate domain and the ambiguity domain. There are many techniques available for searching
the ambiguity domain, such as FARA (Frei and Beutler in Manuscr Geod 15(4):325–356, 1990), LSAST (Hatch in Proceedings of KIS’90, Banff, Canada, pp 299–308, 1990), the modified Cholesky decomposition method (Euler and Landau in Proceedings of the sixth international geodetic symposium on satellite positioning,
Columbus, Ohio, pp 650–659, 1992), LAMBDA (Teunissen in Invited lecture, section IV theory and methodology, IAG general meeting, Beijing, China, 1993), FASF (Chen and Lachapelle in J Inst Navig 42(2):371–390, 1995) and modified LLL Algorithm (Grafarend in GPS Solut 4(2):31–44, 2000; Lou and Grafarend in Zeitschrift für Vermessungswesen 3:203–210, 2003). The widely applied LAMBDA method is based on the Least Squares Ambiguity Search (LSAS) criterion and employs an effective decorrelation technique in addition. G. Xu (J Glob Position Syst 1(2):121–131,
2002) proposed also a new general criterion together with its equivalent objective function for ambiguity searching that can be
carried out in the coordinate domain, the ambiguity domain or both. Xu’s objective function differs from the LSAS function,
leading to different numerical results. The cause of this difference is identified in this contribution and corrected. After
correction, the Xu’s approach and the one implied in LAMBDA are identical. We have developed a total optimal search criterion
for the mixed integer linear model resolving integer ambiguities in both coordinate and ambiguity domain, and derived the
orthogonal decomposition of the objective function and the related minimum expressions algebraically and geometrically. This
criterion is verified with real GPS phase data. The theoretical and numerical results show that (1) the LSAS objective function
can be derived from the total optimal search criterion with the constraint on the fixed integer ambiguity parameters, and
(2) Xu’s derivation of the equivalent objective function was incorrect, leading to an incorrect search procedure. The effects
of the total optimal criterion on GPS carrier phase data processing are discussed and its practical implementation is also
proposed. 相似文献
3.
Asuncion Beamonte Pilar Gargallo Manuel Salvador 《Journal of Geographical Systems》2010,12(2):227-240
In this paper, we extend the Bayesian methodology introduced by Beamonte et al. (Stat Modelling 8:285–311, 2008) for the estimation and comparison of spatio-temporal autoregressive models (STAR) with neighbourhood effects, providing
a more general treatment that uses larger and denser nets for the number of spatial and temporal influential neighbours and
continuous distributions for their smoothing weights. This new treatment also reduces the computational time and the RAM necessities
of the estimation algorithm in Beamonte et al. (Stat Modelling 8:285–311, 2008). The procedure is illustrated by an application to the Zaragoza (Spain) real estate market, improving the goodness of fit
and the outsampling behaviour of the model thanks to a more flexible estimation of the neighbourhood parameters. 相似文献
4.
心象地图及其在地图设计中的作用 总被引：2，自引：0，他引：2
本文首先介绍了心象的含义和心象的来源，然后从地图学的角度，讨论了心象地图的建立方法及其特性，并初步探讨了心象地图在地图设计中的作用。 相似文献
5.
Journal of Geographical Systems - The concept of ‘spatial scale’, or simply ‘scale’ is implicit in any discussion of global versus local models. The raison d’etre of... 相似文献
6.
Forecasting the impact of transport improvements on commuting and residential choice 总被引：1，自引：1，他引：0
This paper develops a probabilistic, competing-destinations, assignment model that predicts changes in the spatial pattern
of the working population as a result of transport improvements. The choice of residence is explained by a new non-parametric
model, which represents an alternative to the popular multinominal logit model. Travel times between zones are approximated
by a normal distribution function with different mean and variance for each pair of zones, whereas previous models only use
average travel times. The model’s forecast error of the spatial distribution of the Dutch working population is 7% when tested
on 1998 base-year data. To incorporate endogenous changes in its causal variables, an almost ideal demand system is estimated
to explain the choice of transport mode, and a new economic geography inter-industry model (RAEM) is estimated to explain
the spatial distribution of employment. In the application, the model is used to forecast the impact of six mutually exclusive
Dutch core-periphery railway proposals in the projection year 2020.
相似文献
| Jan OosterhavenEmail: |
7.
随着专题数据处理向着定量化、辅助决策方向发展,对专题数据处理数学模型提出了更多更高的要求。针对当前制图系统和GIS中数学模型(库)的重用性和可扩展性较差的问题,提出基于元算法的相关概念,并通过对专题数据处理数学模型的深入研究,建立了基于元算法的专题数据处理模型库,最后将该模型库应用到GIS中的专题地图制作中,取得了较好的实验效果。实践证明,基于元算法专题数据处理数学模型库不仅具有建库的高效性,而且具有管理的动态性和使用的灵活性,同时也充分说明基于元算法数学模型库系统具有较大的推广价值。 相似文献
8.
Ant Sibthorpe Willy Bertiger Shailen D. Desai Bruce Haines Nate Harvey Jan P. Weiss 《Journal of Geodesy》2011,85(8):505-517
The subtle effects of different Global Positioning System (GPS) satellite force models are becoming apparent now that mature
processing strategies are reaching new levels of accuracy and precision. For this paper, we tested several approaches to solar
radiation pressure (SRP) modeling that are commonly used by International GNSS Service (IGS) analysis centers. These include
the GPS Solar Pressure Model (GSPM; Bar-Sever and Kuang in The Interplanetary Network Progress Report 42-160, 2005) and variants of the so-called DYB model (Springer et al. in Adv Space Res 23:673–676, 1999). Our results show that currently observed differences between GPS orbit solutions from the various IGS analysis centers
are in large part explained by differences between their respective approaches to modeling SRP. DYB-based strategies typically
generate orbit solutions that have the smallest differences with respect to the IGS final combined solution, largely because
the DYB approach is most commonly used by the contributing analysis centers. However, various internal and external metrics,
including ambiguity resolution statistics and satellite laser ranging observations, support continued use of the GSPM-based
approach for precise orbit determination of the GPS constellation, at least when using the GIPSY-OASIS software. 相似文献
9.
Open source, spatial analysis, and activity-travel behaviour research: capabilities of the aspace package 总被引：2，自引：0，他引：2
This paper reports on recent experience with the development of aspace, an Open Source (OS) library for the geographic visualization and analysis of activity-travel behaviour. The paper begins
with an overview of recent progress with respect to the convergence of Open Source technology, spatial analysis, and travel
behaviour research. The remainder of the paper focuses on aspace; a collection of functions that, when combined with data describing the geographical location of daily activities, can be
used to visualize and describe spatial properties of individual and household activity spaces. These properties include: size,
orientation, shape, and the geographical dispersion of activity locations contained within the activity space. Several planar
geometries are used to transform measurable spatial properties into intuitive objects for visualizing spatial patterns of
activity participation. Experiments are conducted, using data from the first wave of the 2003 Toronto Travel Activity Panel
Survey, to demonstrate the potential application of aspace for basic and applied policy-based research into activity-travel behaviour. The toolkit is distributed as a downloadable
‘package’ from the Open Source R Project for Statistical Computing.
相似文献
10.
随着交通事业的迅猛发展以及人民群众生活水平的不断提高,公众的出行需求发生了巨大的变化,除传统的出行方式外,越来越多的人选择公路自驾车出行,这使得出行服务的内容也随之发生了变化。本文提出了基于Web Service和Flex客户端开发技术建设出行服务系统的思路,设计并实现了青海省便民出行服务系统,系统的建设提高了居民出行的安全性和便利性。 相似文献
11.
A kinematic GPS methodology for sea surface mapping,Vanuatu 总被引：1，自引：0，他引：1
Marie-Noelle Bouin Valérie Ballu Stéphane Calmant Jean-Michel Boré Eric Folcher Jérôme Ammann 《Journal of Geodesy》2009,83(12):1203-1217
During the past few decades, satellite altimetry has brought tremendous new knowledge about the spatial and temporal variations
of sea surface heights over the Earth’s oceans. However, the precision is limited over short wavelengths and in coastal areas,
and other methods such as kinematic GPS may be needed to fill in this information. We present kinematic GPS work aimed at
mapping the sea surface height, with special attention to the precision one can expect. Active marine subduction zones, like
the Vanuatu archipelago, may present short wavelength, high amplitude undulations of the sea surface height that are difficult
to map with satellite altimetry. This paper presents the methodology used around Santo Island, in Vanuatu, to obtain a well-resolved
local sea surface map with a precision of 5–15 cm limited by the sea conditions and the distance from the coastal reference
station. We present the results of three campaigns in 2004, 2006 and 2007. Careful observation of the ship behaviour along
the surveys as well as simultaneous recording of the ship attitude variations is mandatory to obtain reliable results. We
show that the ship GPS antenna height varies with the ship’s velocity and we suggest a method to correct this effect. The
final precision is estimated using the crossover differences method. 相似文献
12.
13.
This paper presents a continuous version of the model of distribution dynamics to analyse the transition dynamics and implied
long-run behaviour of the EU-27 NUTS-2 regions over the period 1995–2003. It departs from previous research in two respects:
first, by introducing kernel estimation and three-dimensional stacked conditional density plots as well as highest density regions
plots for the visualisation of the transition function, based on Hyndman et al. (J Comput Graph Stat 5(4):315–336, 1996), and second, by combining Getis’ spatial filtering view with kernel estimation to explicitly account for the spatial dimension of the
growth process. The results of the analysis indicate a very slow catching-up of the poorest regions with the richer ones,
a process of shifting away of a small group of very rich regions, and highlight the importance of geography in understanding
regional income distribution dynamics.
相似文献
| Manfred M. FischerEmail: |
14.
Land cover mapping forms a reference base for resource managers in their decision-making processes to guide rural/urban growth and management of natural resources. The aim of this study was to map land cover dynamics within the Upper Shire River catchment, Malawi. The article promotes innovation of automated land cover mapping based on remote sensing information to generate data products that are both appropriate to, and usable within different scientific applications in developing countries such as Malawi. To determine land cover dynamics, 1989 and 2002 Landsat images were used. Image bands were combined in transformations and indices with physical meaning; together with spatial data, to enhance classification accuracy. A maximum likelihood classification for each image was computed for identification of land cover variables. The results showed that the combination of spatial and digital data enhanced classification accuracy and the ability to categorise land cover features, which are relatively inhomogeneous. 相似文献
15.
文中论述了按需印刷和复制的概念、应用特点及与传统印刷方式相比的优点。数字印刷是地图按需印刷和复制的技术基础，文中分析了其成像方法和设备情况。指出了地图按需印刷和复制的技术途径及技术难点。 相似文献
16.
Personalized travel route recommendation using collaborative filtering based on GPS trajectories 总被引：1，自引：0，他引：1
Travelling is a critical component of daily life. With new technology, personalized travel route recommendations are possible and have become a new research area. A personalized travel route recommendation refers to plan an optimal travel route between two geographical locations, based on the road networks and users’ travel preferences. In this paper, we define users’ travel behaviours from their historical Global Positioning System (GPS) trajectories and propose two personalized travel route recommendation methods – collaborative travel route recommendation (CTRR) and an extended version of CTRR (CTRR+). Both methods consider users’ personal travel preferences based on their historical GPS trajectories. In this paper, we first estimate users’ travel behaviour frequencies by using collaborative filtering technique. A route with the maximum probability of a user’s travel behaviour is then generated based on the naïve Bayes model. The CTRR+ method improves the performances of CTRR by taking into account cold start users and integrating distance with the user travel behaviour probability. This paper also conducts some case studies based on a real GPS trajectory data set from Beijing, China. The experimental results show that the proposed CTRR and CTRR+ methods achieve better results for travel route recommendations compared with the shortest distance path method. 相似文献
17.
传统旅游信息系统注重旅游信息的查询以及决策和管理,很少有自主发布信息的、个性化的、注重自主享受旅游和回顾评价旅游过程的信息系统出现。为此,本文以C#语言为基础用ArcGIS Engine二次开发的方法,设计和实现了一个自主旅游信息系统原型,详细剖析了该系统的设计和实现流程,测试表明该系统能初步满足游客个性化旅游的要求,为宣传“智慧旅游”提供了新的方法和手段。 相似文献
18.
Exploring differences of visual attention in pedestrian navigation when using 2D maps and 3D geo-browsers 总被引：1，自引：0，他引：1
ABSTRACTDespite the now-ubiquitous two-dimensional (2D) electronic maps, three-dimensional (3D) globe viewers, or 3D geo-browsers such as Google Earth and NASA World Wind have gained much attention. However, the effect of such interactive 3D geo-browsers on spatial knowledge acquisition and decision-making is not well known. This study aims to explore the potential benefits of using interactive 3D geo-browsers in three processes of pedestrian navigation (self-localization, spatial knowledge acquisition, and decision-making) in digital environments. We employed eye tracking to show differences of visual attention in pedestrian navigation between a 2D map (Google Map) and a 3D geo-browser (Google Earth). The results indicated that benefits and drawbacks of 3D representations are task dependent. Participants using the 3D geo-browser had an extensively visual search resulting in significantly longer response time than the 2D participants for spatial knowledge acquisition, whereas 3D users performed a more efficient visual search and resulted in a better navigation performance at complex decision points. We speculate that the inefficient knowledge acquisition when using the 3D geo-browser was most probably due to information overload and obstructed views. Landmarks in photorealistic 3D models assisted recall of spatial knowledge from mental maps, which contributed to efficient decision-making at a complex turning point. These empirical results can be helpful to improve the usability of pedestrian navigation systems. 相似文献
19.
20.
J. Feltens 《Journal of Geodesy》2011,85(4):239-254
The vector-based algorithms for biaxial and triaxial ellipsoidal coordinates presented by Feltens (J Geod 82:493–504, 2008; 83:129–137, 2009) have been extended to hyperboloids of one sheet. For the backward transformation from Cartesian to hyperboloidal coordinates,
of two iterative process candidates one was identified to be well suited. It turned out that a careful selection of the center
of curvature is essential for the establishment of a stable and reliable iteration process. In addition, for zero hyperboloidal
heights a closed solution is presented. The hyperboloid algorithms are again based on simple formulae and have been successfully
tested for various theoretical hyperboloids. The paper concludes with a practical application example on a cooling tower construction. 相似文献