共查询到20条相似文献,搜索用时 0 毫秒
1.
Peter Congdon 《Computational statistics & data analysis》2007,51(6):3197-3212
Mixture models are used for spatially adaptive smoothing of health event data (e.g. mortality or illness totals). Such models allow for spatial pooling of strength where appropriate but adopt a mixture strategy that also reflects health risks that are discordant with those of surrounding areas. Mixing is either discrete or based on beta densities. A fully Bayesian estimation and specification strategy is applied with fit based on DIC and BIC criteria. Illustrative applications are to long term illness in 133 London small areas, where event counts are large, and to lip cancer in Scottish counties where the majority of event totals are under 10. 相似文献
2.
Dongrui Han Hongyan Cai Xinliang Xu Zhi Qiao Chuanzhou Cheng 《International journal of remote sensing》2019,40(14):5287-5300
Fine-scale population gridded datasets are of great significance in emergency response, resource allocation, and traffic planning. Many studies have developed fine-scale population spatialization models based on building patch area (BPA) and building floor (BF). However, little attention has been given to house occupancy rate (HOR). Based on BPA, BF and HOR, this study proposed a novel fine-scale population spatialization method, taking the six districts of Beijing as the study area. The results showed that the HOR in central Beijing was higher than that of the surrounding area. The model with consideration of HOR was more accurate than that without it. In addition, the fine-scale population gridded map generated by this novel method was more accurate (mean prediction error = 8.47%). For all the testing samples, the relative errors of the population gridded data were between ?13.54% and 16.04%. Thus, this study suggested that HOR could be a key indicator for fine-scale population modelling. Furthermore, the proposed method could be employed in generating fine-scale population gridded maps and could provide credible and fundamental data for rapid response and decision-making. 相似文献
3.
While learning biological topics constructing depictive representations may be the first step to a deeper understanding. The referred to as visualization type as well as interaction type are supposed to have influence on learning with multimedia applications. Comparing 3D and 2D visualizations (both in combination with written text), there is little evidence whether stereoscopic 3D visualizations better support the understanding of biological topics by constructing adequate depictive representations. Likewise, insufficient indication is given of how the interaction type impacts these results (e.g. the ability/disability to move and rotate the displayed object). Therefore, our study focused on an e-learning environment dealing with the anatomy and physiology of the nasal cavity. Here, either (1) text and 2D visualisations or (2) text and stereoscopic 3D visualisations were used – both in combination with two interaction types (interaction/no interaction). Research subjects were 144 eighth grade students at medium stratification level. During a working phase with the different multimedia applications (visualization type 2D/stereoscopic 3D and interaction type ‘interaction’/‘no interaction’) the students were instructed to form the nasal cavity out of modeling clay. Finally, for both interaction types the 3D cohorts were by far more successful in representing anatomical details. Hence, stereoscopic 3D technology should be implemented in biological e-learning environments. 相似文献
4.
Modelling small area counts in the presence of overdispersion and spatial autocorrelation 总被引:1,自引:0,他引:1
The problems arising when modelling counts of rare events observed in small geographical areas when overdispersion and residual spatial autocorrelation are present or anticipated are considered. Different models are presented for handling inference in this case. The different strategies are implemented using data on offender counts at the enumeration district scale for Sheffield, England and results compared. This example is chosen because previous research suggests that social processes and social composition variables are key to understanding geographical variation in offender counts which will, as a consequence, show evidence of clustering both at the scale of the enumeration district and at larger scales. This in turn leads the analyst to anticipate the presence of overdispersion and spatial autocorrelation. Diagnostic measures are described and different modelling strategies are implemented. The evidence suggests that modelling strategies based on the use of spatial random effects models or models that include spatial filters appear to work well and provide a robust basis for model inference but gaps remain in the methodology that call for further research. 相似文献
5.
B. Anselme F. Bousquet A. Lyet M. Etienne B. Fady C. Le Page 《Environmental Modelling & Software》2010,25(11):1385-1398
Our study is part of a multi-disciplinary research project aimed at stimulating debate among researchers and local managers. The central question of this multi-disciplinary research project was to better understand and manage high biodiversity value open habitats threatened with shrub encroachment and landscape closure, a common problem throughout Europe. Here, we study shrub encroachment and its impact on biodiversity conservation in Mount Ventoux, a MAB Biosphere Reserve located at the southernmost tip of the French Alps. We show how using a multi-agent modelling approach provide a valuable framework to confront two potentially conflicting conservation efforts in this mountain Mediterranean landscape, that of the within-species diversity of a tree (Abies alba, the European silver fir) and that of an endangered species (Vipera ursinii ursinii, the Orsini viper). A companion modelling approach – approach which aims at transmitting and sharing knowledge, methods and tools that help understand and strengthen the collective decision making process of stakeholders sharing a common resource – was used in order to collectively represent the main activities underway on the mountain and to have a tool to address both open landscapes rehabilitation and restoration of forest environments. The co-construction of the model allowed us to build a shared representation of the territory under study and to develop and compare alternative management scenarios with local stakeholders, both to evaluate their impact on biodiversity and to provide information for forest and grazing management practice. 相似文献
6.
John Lim 《Behaviour & Information Technology》2000,19(5):329-338
Negotiations are often not as rational as desired due to the cognitive difficulty of finding optimal agreements. With higher information-processing capacity and capability, negotiation support systems (NSS) are viewed as a viable solution to overcome this difficulty and help negotiators achieve integrative agreements. In addition, advances in network communication technology have enabled distributed meetings to be carried out easily. This in turn leads to the notion of conducting distributed negotiations by combining NSS and distributed communication technology. This study examined the impact of NSS in face-to-face and distributed settings. The results suggested that NSS led to higher and fairer outcomes for both face-to-face and distributed dyads. Another interesting finding from this study is that there were gains with respect to initial expectations of outcomes when NSS support was provided. As corporations expand globally, NSS will play a significant role in coordinating distributed negotiations, saving time and cost. 相似文献
7.
《Behaviour & Information Technology》2012,31(12):1225-1241
Understanding the impact of service quality on economic and social outcomes is critical to extend the focus of IT service research. This study evaluates the impact of quality on both these dimensions in mHealth using a cross disciplinary approach. The conceptual model is rooted in the traditional cognition–affective–conation chain but explicitly incorporates convenience, confidence, cooperation, care and concern as the primary dimensions of mHealth quality. The model is validated in the context of a business-to-consumer mHealth services using partial least squares path modelling. The results confirm that service quality has both direct and indirect impact on continuance intentions (i.e. economic outcome) and quality of life (i.e. social outcome). In this relationship, satisfaction plays the key mediating role, whereas service quality does not have any moderating effect. Research implications point to scale and sustain this new healthcare paradigm by linking service quality to satisfaction, continuance intentions and quality of life. 相似文献
8.
《Behaviour & Information Technology》2012,31(5):329-338
Negotiations are often not as rational as desired due to the cognitive difficulty of finding optimal agreements. With higher information-processing capacity and capability, negotiation support systems (NSS) are viewed as a viable solution to overcome this difficulty and help negotiators achieve integrative agreements. In addition, advances in network communication technology have enabled distributed meetings to be carried out easily. This in turn leads to the notion of conducting distributed negotiations by combining NSS and distributed communication technology. This study examined the impact of NSS in face-to-face and distributed settings. The results suggested that NSS led to higher and fairer outcomes for both face-to-face and distributed dyads. Another interesting finding from this study is that there were gains with respect to initial expectations of outcomes when NSS support was provided. As corporations expand globally, NSS will play a significant role in coordinating distributed negotiations, saving time and cost. 相似文献
9.
《International journal of remote sensing》2013,34(18):6662-6673
High-frequency injection (HFI)-based methods are proved to be powerful in pansharpening multispectral (MS) images. In this article, based on one of the low-rank and sparse (LRS) decomposition algorithms, i.e. Go Decomposition (GoDec), a HFI-based pansharpening method exploiting spatial structure sharpness of both MS images and a low-frequency panchromatic (PAN) image component is proposed. The spectral and spatial measure of local perceived sharpness (S3) is employed to estimate sharpness of the corresponding MS and low-frequency PAN component blocks, and the sharper one is used to construct the spatial structure of the sharpened MS images. Experimental results with QuickBird, IKONOS and WorldView-2 data demonstrate that the proposed method is comparable with or even better than other popular methods. 相似文献
10.
People learn the layout of cities mainly through a series of trips. Wayfinders experience the city structure differently depending on the mode of transport they use. The acquired mental representation then consists of the directly observed, physically accessible parts of the city. In this paper, we propose a computational model to construct images of cities, adapting their content depending on the wayfinder’s access constraints. First, we formally study and extend the classification of Lynch’s elements of the city form. Second, we propose a simple approach to analyzing local functional relationships between these elements, as experienced by wayfinders. The study of the functional relationships allows for the construction of the most complete image of the city that might be acquired by a wayfinder with given accessibility characteristics. These representations of urban environments can support advanced spatial assistance systems and cognitively efficient spatial interfaces. 相似文献
11.
颜彬 《计算机工程与设计》2004,25(8):1390-1392
提出了基于空域结构的纹理识别算法。用纹理的基元结构分布与纹理分布字典参数进行了相关及旋转相关比较,得出了纹理归类结果及纹理相似的最佳精度,用可识别纹理参数调整纹理分布字典,使之具有自适应性。实验结果表明,用本算法识别的纹理与视觉识别结果高度一致。 相似文献
12.
Rasmussen S 《Computer methods and programs in biomedicine》2004,76(1):83-89
SAS provides a macro GLIMMIX, which can be used for modelling of discrete spatial variation in epidemiological studies, where data are aggregated into small areas such as municipalities or postcode sectors. The purpose of these models is primary to examine to what extent unmeasured spatially correlated variables can explain the outcome of interest. Some necessary additional code is proposed for this macro implementing some of the most used models for analysing and exploring spatial variation, in for example Poisson and logistic regression: Gaussian intrinsic conditional autoregression and spatial multiple memberships models originated from multilevel models. The code is illustrated by analysing the well-known Scottish lip cancer dataset with GLIMMIX and the results are compared with a Markov chain Monte Carlo approach. The code gives epidemiologists and bio-statisticians an immediate tool for analysing discrete spatial models in a familiar statistical software package. 相似文献
13.
This study examined how a person's negative experiences with computers prior to a training class interacted with their motivation to predict their performance in a computer class. Participants were 384 students who completed a computer course that was designed to introduce them to personal computers and a popular software package. Questionnaires were administered to the participants on the first day of the course to assess their prior negative experiences with computers, along with their computer attitudes, achievement motivation, and computer knowledge. Performance was measured objectively throughout the course with tests over the relevant material. Results indicated some evidence that the participants' pre-training motivation was moderated by their prior negative experiences when predicting test performance. 相似文献
14.
《Information & Management》2016,53(7):892-903
Information technology is deeply ingrained in most aspects of everyday life and can be designed to influence users to behave in a certain way. Influencing students to improve their study behaviour would be a useful application of this technology. As a preamble to the design of a persuasive system for learning, we collected data to identify the study behaviours of students and recent alumni. We then developed two models to measure which behaviours have the most significant impact on learning performance. Current students reported more foundational behaviours whereas alumni demonstrated more higher-order thinking traits. 相似文献
15.
The AS-level topology of the Internet has been quite a hot research topic in the last few years. However, only a small number of studies have been developed that give a structural interpretation of this graph. Such an interpretation is crucially important in order to test protocols and optimal routing algorithms, to design efficient networks, and for failure detection purposes. Moreover, most research does not highlight the role that IXPs have on the AS-level structure of the Internet, although their role is recognized as fundamental.The initial contribution of this study is an analysis of the most important AS-level topologies that are publicly found on the web and an analysis of the topology obtained when they are merged. We compiled structural information from this topology making considerable use of the k-core decomposition technique to delineate various particular classes of nodes. Next, we associated node properties with a reasonable modus operandi of the ASs on the Internet. The second contribution is a study of the impact that ASs connected to IXPs and BGP connections crossing IXPs have on the AS-level topology. To achieve this, we developed a procedure to gather reliable information related to IXPs and their participants. 相似文献
16.
Perfect knowledge of future driving conditions can be rarely assumed on real applications when optimally splitting power demands among different energy sources in a hybrid electric vehicle. Since performance of a control strategy in terms of fuel economy and pollutant emissions is strongly affected by vehicle power requirements, accurate predictions of future driving conditions are needed. This paper proposes different methods to model driving patterns with a stochastic approach. All the addressed methods are based on the statistical analysis of previous driving patterns to predict future driving conditions, some of them employing standard vehicle sensors, while others require non-conventional sensors (for instance, global positioning system or inertial reference system). The different modelling techniques to estimate future driving conditions are evaluated with real driving data and optimal control methods, trading off model complexity with performance. 相似文献
17.
Consider the situation where the Structuration des Tableaux à Trois Indices de la Statistique (STATIS) methodology is applied to a series of studies, each study being represented by data and weight matrices. Relations between studies may be captured by the Hilbert-Schmidt product of these matrices. Specifically, the eigenvalues and eigenvectors of the Hilbert-Schmidt matrix S may be used to obtain a geometrical representation of the studies. The studies in a series may further be considered to have a common structure whenever their corresponding points lie along the first axis. The matrix S can be expressed as the sum of a rank 1 matrix λuuT with an error matrix E. Therefore, the components of the vector are sufficient to locate the points associated to the studies. Former models for S where vec(E) are mathematically tractable and yet do not take into account the symmetry of the matrix S. Thus a new symmetric model is proposed as well as the corresponding tests for a common structure. It is further shown how to assess the goodness of fit of such models. An application to the human immunodeficiency virus (HIV) infection is used for assessing the proposed model. 相似文献
18.
This Theme issue focuses on the emerging research of ubiquitous technologies to support mental health. So far, the majority of work presented in the field of ubiquitous healthcare has focused on supporting people affected by somatic diseases. However, increasing number of diseases affecting mental health has prompted research on technologies to support people suffering from these diseases. This Theme issue provides a number of examples of research on the potential impact of ubiquitous technologies in the field of mental health. 相似文献
19.
Costa G 《Applied ergonomics》1996,27(1):9-16
Shift work, in particular night work, can have a negative impact on health and well-being of workers as it can cause: (a) disturbances of the normal circadian rhythms of the psychophysiological functions, beginning with the sleep/wake cycle; (b) interferences with work performance and efficiency over the 24 hour span, with consequent errors and accidents; (c) difficulties in maintaining the usual relationships both at family and social level, with consequent negative influences on marital relations, care of children and social contacts; (d) deterioration of health that can be manifested in disturbances of sleeping and eating habits and, in the long run, in more severe disorders that deal prevalently with the gastrointestinal (colitis, gastroduodenitis and peptic ulcer), neuro-psychic (chronic fatigue, anxiety, depression) and, probably, cardiovascular (hypertension, ischemic heart diseases) functions. Besides, shift and night work may have more specific adverse effects on women's health both in relation to their particular hormonal and reproductive function, and their family roles. It has been estimated that about 20% of all workers have to leave shift work in a very short time because of serious disturbances; those remaining in shift work show different levels of (mal)adaptation and (in)tolerance, that can become more or less manifest in different times, and with different intensity. In fact, the effects of such stress condition can vary widely among the shift workers in relation to many 'intervening variables' concerning both individual factors (e.g. age, personality traits, physiological characteristics), as well as working situations (e.g. work loads, shift schedules) and social conditions (e.g. number and age of children, housing, commuting). 相似文献
20.
OBJECTIVE: This study examined the effects of night vision goggles (NVGs) on navigation and way-finding performance and the acquisition of spatial knowledge. BACKGROUND: Although numerous studies have examined the effects of NVGs on visual perception, few have examined the effects of using NVGs on the acquisition and expression of spatial cognition. METHOD: Participants learned the environment through active navigation and way finding, searching for targets within a life-sized maze with or without NVGs. Knowledge of the environment was then tested with two spatial memory tests. RESULTS: Findings show that navigation and way finding with NVGs appear to be harder, as indicated by longer navigation times and additional, unnecessary turns, than they are without NVGs. Moreover, change in navigation performance over the course of the way-finding trials varied as a function of group assignment indicating that NVGs influenced the learning process. NVG users demonstrated a significant decrease in navigation times earlier as well as significant decreases in navigational legs compared with the control group. In judging the positions of objects relative to target objects in different rooms in the maze, performance was better for participants without NVGs than for those with NVGs. In a map-drawing task, participants in the NVG group were more likely to position objects incorrectly and to receive worse scores than the controls. CONCLUSION: These results demonstrate that NVGs affected not only spatial navigation and way-finding performance but also the acquisition of spatial knowledge. APPLICATION: These degradations in spatial knowledge should be considered in operational planning and NVG training programs. 相似文献