信息条件下基于预期后悔更新生成备选路径仿真研究*

为了研究影响私家车驾驶者备选路径生成的因素,以预期后悔理论为基础,借助贝叶斯网络推理方法,计算了私家车驾驶者受先验知识和出行信息双重影响下的备选路径生成。通过改进的贝叶斯网络结构和参数学习程序建立了实验路网的贝叶斯网络结构,对生成的网络结构进行了参数学习,模拟了不同出行信息和先验条件下生成的备选路径,得出了驾驶者备选路径生成与驾驶者先验知识和出行信息的变化关系。     

基于居民出行行为分析的公交线路调度研究

针对居民出行高峰时段的交通拥堵问题,建立了以居民的出行行为分析为基础的公交线路调度模型。该模型运用生存分析理论对居民出行时间的影响因素进行分析,科学划分城市居民出行时段区间,进而针对该地区高峰时段的公交发车间隔构造非线性规划模型函数。模型函数综合考虑乘客时间成本和公交公司运营成本,加入权重系数并利用粒子群算法求解,从而得到最佳发车间隔时间。结合杭州某地区市民出行数据,通过实证研究得出优化后的调度时刻表,验证了模型的可行性和有效性。     

贝叶斯网络及其在决策支持系统中的应用

以贝叶斯概率和贝叶斯网络基本理论为基础，主要研究了贝叶斯网络的结构学习和使用贝叶斯网络进行知识发现和决策支持的方法。利用WILD算法对防洪数据进行了属性离散化，采用K2算法在防洪决策中建立了一种贝叶斯网络模型，并对该模型进行了概率依赖关系描述。说明了贝叶斯网络对数据库进行知识发现和决策支持的有效性。     

基于市民出行模式的拥堵综合治理对策研究--以温州市鹿城区为例

以温州市鹿城区为例,基于居民在不同时间节点下出行方式选择的实地调查,通过分析调查数据,定性得出影响居民出行方式的因素。为了定量表述各影响因素的影响程度,建立市民出行方式选择预测模型。模型能描述在不同时间节点下各影响因素所占的权重大小,更好的为居民选择出行方式提供一定的理论指导。另外,还根据调查问卷并结合温州实地情况,提出拥堵治理建议。     

用于风险管理的贝叶斯网络学习

结合专家知识和数据进行贝叶斯网络学习.首先利用专家知识建立初始贝叶斯网络结构和参数;然后基于变量之间基本依赖关系、基本结构和依赖分析方法,对初始贝叶斯网络结构进行修正和调整,得到新的贝叶斯网络结构;最后将由专家和数据确定的参数合成为新的参数,得到融合专家知识和数据的贝叶斯网络.该方法可避免现有的贝叶斯网络学习过于依赖数据、对数据的数量和质量要求过高等问题.     

基于改进贝叶斯网络的健康大数据分类模型

贝叶斯网络是数据挖掘领域的研究热点,它是一种确定事物间不确定性依赖关系的有效工具。本文研究传统贝叶斯网络结构学习算法的优点和不足,并针对原算法的不足之处提出了改进。将改进后的算法应用于健康大数据集上,确定了数据集中各个健康属性之间的依赖关系,建立了相关属性依赖关系的网络结构。最终运用该网络结构对数据集中的数据进行自动分类。实验结果表明,本文基于贝叶斯网络建立的健康大数据分类模型具有良好的性能,实现了预期效果。     

混合多元回归学习模型的改进

研究统计方法分析问题,针对在实际应用外特性模型的输入普遍为混合变量,既包括连续随机变量,也包括离散随机变量.目前已有混合多元回归学习模型大多只处理连续随机变量,且有着多重共线性的缺陷.针对上述问题,研究了基于贝叶斯网络的回归树学习模型.基于贝叶斯网络的回归树学习模型的研究方法建立在朴素贝叶斯网络模型基础上,采用分而治之的原则构造决策树,以朴素贝叶斯取代叶节点.在2个UCI机器学习数据集上的仿真实验结果表明模型性能良好.基于贝叶斯网络的回归树学习模型可以有效减小预测误差.     

贝叶斯网络结构学习综述

贝叶斯网络是一种有效的不确定性知识表达和推理工具,在数据挖掘等领域得到了较好的应用,而结构学习是其重要研究内容之一.经过二十多年的发展,已经出现了一些比较成熟的贝叶斯网络结构学习算法,对迄今为止的贝叶斯网络结构学习方法进行了综述.现阶段获得的用于结构学习的观测数据都比较复杂,这些数据分为完备数据和不完备数据两种类型.针对完备数据,分别从基于依赖统计分析的方法、基于评分搜索的方法和混合搜索方法三个方面对已有的算法进行分析.对于不完备数据,给出了数据不完备情况下网络结构的学习框架.在此基础上归纳总结了贝叶斯网络结构学习各个方向的研究进展,给出了贝叶斯网络结构学习未来可能的研究方向.     

一种改进的贝叶斯网络结构学习分类模型及应用

贝叶斯网络结构的构建是贝叶斯网络分类的重点,有效的贝叶斯网络结构学习算法是构建贝叶斯网络的核心。改进的贝叶斯网络结构学习算法使用交叉熵来确定弧的方向,用最小切割集来对有向图进行调整,并且加入环路检验以保证图中不会出现回路。将算法应用到质量管理中,用实际的数据集进行实验,并与现有算法进行对比,结果表明该算法是行之有效的,且具有较高的精确性。     

基于多源出行数据的居民行为模式分析方法

基于对智能交通卡数据的挖掘与分析能够为城市交通建设和城市管理提供有力支持,但现有研究数据大都仅包含公交或地铁这两方面数据,且主要关注群体性宏观出行规律。针对这一问题,以某城市交通卡数据为例,该数据包含着城市居民日常出行公交、地铁、出租车等多源数据,首先提出行程链的概念对居民出行行为建模,在此基础上给出不同维度的周期性出行特征;然后提出一种基于最长公共子序列的空间周期性特征提取方法,并对城市居民出行规律进行聚类分析;最后通过规则定义5个评价指标对该方法的有效性进行初步验证。结果表明引入该方法的聚类算法对聚类结果有6.8%的效果提升,有利于发现居民的行为模式。     

基于贝叶斯网络的不确定因果逻辑量化分析方法

在安全苛求系统中,潜在风险会引发灾难事故,研究分析潜在风险的影响至关重要. 风险到事故的因果逻辑关系包括两类：确定性和非确定性的. 确定性因果关系可以用事件树、故障树等分析. 由于非确定性因果关系包含不确定性因素和数据不足,贝叶斯网络成为最佳选择. 量化分析中,条件概率的分配是一件不容易的工作,本文提出一种基于模糊逻辑的分配方法,结合建立的不确定性影响模型,利用贝叶斯网络进行量化分析,分析确定性因素的影响. 最后通过实例学习,验证和评估方法的有效性.     

基于大规模GPS轨迹数据的出租车换道行为研究

出租车换道行为的统计特性对研究经济、心理等人类动力学有重要的意义.结合大数据分析技术,基于西安市出租车GPS轨迹数据对出租车司机的换道行为进行了定量研究.设计了一种基于出租车GPS轨迹数据的出租车司机换道行为识别模型,利用大数据平台对出租车司机换道次数按不同时段进行了定量统计,对出租车司机换道次数、出租车平均行驶速度和出租车司机的收入之间进行了相关性分析.分析结果表明,出租车频繁换道行为对司机收益呈现负相关影响,进一步说明出租车司机驾驶习惯和和心理对整个出租车运营有显著影响.     

基于模糊信息分配的水环境质量评价

将模糊信息分配方法应用到水环境质量评价中，以西安市水环境质量评价为例进行了检验计算，结果表明：评价结果能较准确地反映水环境质量的实际情况，最后对其进行了合理的分级，具有一定的应用价值，为水环境保护和管理提供依据。     

Workplace slip,trip and fall injuries and obesity

The objective of this study was to examine the relationship between slip, trip and fall injuries and obesity in a population of workers at the Idaho National Laboratory (INL) in Idaho Falls, Idaho. INL is an applied engineering facility dedicated to supporting the US Department of Energy's mission. An analysis was performed on injuries reported to the INL Medical Clinic to determine whether obesity was related to an increase in slip, trip and fall injuries. Records were analysed that spanned a 6-year period (2005–2010), and included 8581 employees (mean age, 47 ± 11 years and body mass index [BMI], 29 ± 5 kg/m²; 34% obesity rate). Of the 189 people who reported slip, trip and fall injuries (mean age, 48 ± 11 years), 51% were obese (P < 0.001 compared with uninjured employees), and their mean BMI was 31 ± 6 kg/m² (P < 0.001). Obesity in this population was associated with a greater rate of slip, trip and fall injuries.     

基于贝叶斯网络的个体隐性知识测度方法研究

隐性知识是企业创新力和竞争力的源泉，因此对其进行合理地表达、转换、分享和测度，将会为企业带来无形却巨大的经济效益。基于此，提出基于贝叶斯网络的个体隐性知识测度方法。构建了包括特定情境的设定和分析，贝叶斯网络拓扑结构的构建、节点概率的参数学习，贝叶斯网络的概率推理、排序和解释及其模型的有效性测试等在内的个体隐性知识测度模型。最后，以L企业研发部的招聘活动为例进行算例分析。结果表明该算例模型的有效性约为75%～80%，验证了所提方法对隐性知识的客观量化测度具有较好可行性和有效性。     

A Bayesian network and analytic hierarchy process based personalized recommendations for tourist attractions over the Internet

Selecting tourist attractions to visit at a destination is a main stage in planning a trip. Although various online travel recommendation systems have been developed to support users in the task of travel planning during the last decade, few systems focus on recommending specific tourist attractions. In this paper, an intelligent system to provide personalized recommendations of tourist attractions in an unfamiliar city is presented. Through a tourism ontology, the system allows integration of heterogeneous online travel information. Based on Bayesian network technique and the analytic hierarchy process (AHP) method, the system recommends tourist attractions to a user by taking into account the travel behavior both of the user and of other users. Spatial web services technology is embedded in the system to provide GIS functions. In addition, the system provides an interactive geographic interface for displaying the recommendation results as well as obtaining users’ feedback. The experiments show that the system can provide personalized recommendations on tourist attractions that satisfy the user.     

Use of a Bayesian network for Red Listing under uncertainty

The IUCN (International Union for Conservation of Nature) Red List is widely recognised as an authoritative assessment of the conservation status of species. However, the data available for Red Listing are often lacking or uncertain. This paper presents a Bayesian network that may be used to perform a Red List assessment of a taxon using uncertain data. In such cases, input variables can be entered as likelihoods, and the appropriate Red List category is identified by the network using Bayesian inference. Relative performance of the Bayesian network was evaluated by comparison with an alternative method (RAMAS^® Red List), based on the use of fuzzy numbers. While results were generally comparable, some differences were noted for species with uncertain input data. Contrasting results may be attributed to differences in how uncertain data are analysed by the two approaches. The Bayesian network has the advantage of being more transparent, facilitating sensitivity analysis. The method consequently has potential for facilitating Red List assessments, particularly for poorly known taxa.     

Synthesising carbon emission for mega-cities: A static spatial microsimulation of transport CO2 from urban travel in Beijing

Developing low carbon cities is a key goal of 21st century planning, and one that can be supported by a better understanding of the factors that shape travel behaviour, and resulting carbon emissions. Understanding travel based carbon emissions in mega-cities is vital, but city size and often a lack of required data, limits the ability to apply linked land use, transport and tactical transport models to investigate the impact of policy and planning interventions on travel and emissions. Here, we adopt an alternative approach, through the development of a static spatial microsimulation of people’s daily travel behaviour. Using Beijing as a case study, we first derive complete activity-travel records for 1026 residents from an activity diary survey. Then, using the 2000 population census data at the sub-district level, we apply a simulated annealing algorithm to create a synthetic population at fine spatial scale for Beijing and spatially simulate the population’s daily travel, including trip distance and mode choice at the sub-district scale. Finally, we estimate transport CO₂ emission from daily urban travel at the disaggregate level in urban Beijing.     

Learning implicit information in Bayesian games with knowledge transfer

In this paper, we consider to learn the inherent probability distribution of types via knowledge transfer in a two-player repeated Bayesian game, which is a basic model in network security. In the Bayesian game, the attacker''s distribution of types is unknown by the defender and the defender aims to reconstruct the distribution with historical actions. It is difficult to calculate the distribution of types directly since the distribution is coupled with a prediction function of the attacker in the game model. Thus, we seek help from an interrelated complete-information game, based on the idea of transfer learning. We provide two different methods to estimate the prediction function in different concrete conditions with knowledge transfer. After obtaining the estimated prediction function, the defender can decouple the inherent distribution and the prediction function in the Bayesian game, and moreover, reconstruct the distribution of the attacker''s types. Finally, we give numerical examples to illustrate the effectiveness of our methods.     

Sensitivity analysis on causal chains of Bayesian networks

To analyze the key path of Bayesian network in complex systems, this study proposes to analyze the sensitivity of causal chains of Bayesian networks using the Petri net structural analysis approach to obtain the key chain through which the cause influences the consequence. First, the Bayesian network is transformed into Petri net, the structural analysis approach of which is employed to analyze structural nature of the Bayesian network, ensuring correctness of the constructed Bayesian network structure. Then based on the above fact that the structure is correct, S‐invariants of a Petri net is used to search for simple causal chains of the Bayesian network. Finally, the causal effect is defined and sensitivity analysis is made on the causal chains. The said method is applied to MDS causal chain analysis. Results show that the proposed method is direct viewing and practical. This method has some reference value for decision making in complex systems. © 2011 Wiley Periodicals, Inc.