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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <title>Constructing the feasible space–time region of the Household Activity Pattern Problem</title>
      <link>https://trid.trb.org/View/1412891</link>
      <description><![CDATA[In this paper, a method of constructing the feasible region in space–time dimension of the well-known Household Activity Pattern Problem (HAPP) is developed. HAPP is an optimization model that generates an optimal set of full-day activity-travel decisions. Based on the definition of an activity and its spatial and temporal constraints, feasible space–time region for the completion of one activity is derived. Then, a full-day feasible space–time region is determined as an intersection of a set of feasible regions for activities to be performed on a given travel day. This feasible space–time region is shown to be consistent with the concept of space–time prism. An algorithm is developed for the construction of an activity-specific feasible space–time region for a network-based travel environment. The algorithm generates a set of time windows for each activity and for each node that later converts to link-based time windows of accessibility.]]></description>
      <pubDate>Wed, 27 Jul 2016 09:49:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1412891</guid>
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    <item>
      <title>Space-Time Networks Construction Analysis Based on Railway Wagon-Flow Adjustment</title>
      <link>https://trid.trb.org/View/1276481</link>
      <description><![CDATA[Railway wagon-flow organization and adjustment are connected and influence each other, solve mainly the problem of departure trains on every route direction in railway networks, and absorb wagon flows by every train flow. The change of railway wagon-flow organization and the problem that needed to be solved in recent years were analyzed. On the basis of previous research, the construction method of space-time network was described on basis of physical network that has already definite traveling time and the two parameters including time and station. The construction of the space-time network based on the characteristic of railway wagon-flow adjustment helps to catch the dynamic characteristic in the course of freight transportation. It laid the foundation for constructing a model of railway wagon-flow organization and adjustment.]]></description>
      <pubDate>Mon, 03 Mar 2014 09:30:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1276481</guid>
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    <item>
      <title>Empirical Characteristics of Vehicular (Lagrangian) Fundamental Diagrams and Shock Waves</title>
      <link>https://trid.trb.org/View/1093398</link>
      <description><![CDATA[Traditional macroscopic traffic flow modeling has been focused on the spatial-temporal coordinate system and considering the vehicle as a dependent variable or function with respect to space and time. Such analyzing method has difficulties in dealing with traffic flow data collected from the modern probe vehicle technologies, which are not collected in a fixed space and fixed time but for fixed vehicles at either variable locations or times. With the introduction of the vehicular (Lagrangian) coordinate and the related first-order models, it is now possible to consider the vehicular dimension equally as the spatial x and temporal t dimension when modeling traffic flow dynamics. A key foundation for this method is the empirical characteristics (e.g. Fundamental Diagrams) with respect to vehicular coordinate. But most existing findings are in the space-time coordinates and transforming those findings between different coordinates is not always trivial and accurate. With the above considerations, an empirical study for vehicular coordinate is conducted in this paper to 1) evaluate the characteristics of traffic state measurements in vehicular coordinate systems; 2) compare the fundamental diagrams generated using vehicular traffic states; and 3) correlate and analyze shock waves in different coordinate systems. Edie’s equations for calculating traffic states in x-t coordinates are extended to calculate traffic states from trajectories in n-t and n-x coordinates. Two NGSIM (Next Generation SIMulation) freeway datasets are used as the field data for this study.]]></description>
      <pubDate>Fri, 25 Mar 2011 10:28:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1093398</guid>
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    <item>
      <title>Image-Based Vehicle Localization Using a Series of Building Height Information Timeline Height Image and Texuring Building Model</title>
      <link>https://trid.trb.org/View/908420</link>
      <description><![CDATA[This paper proposes a novel expression of space-time volume, called Temporal Height Image (THI). Assigning a gray value in proportion to height to all the objects in this space-time volume, the authors can obtain THI by looking at the volume from above. THI is supposed to be applied to urban area mainly. Having the similar concept to Epipolar Plane Image (EPI), but THI can overcome the shortages of EPI (i.e. edges inside the building disrupt result). In this paper, after constructing THIs from actual urban image and 3D-city model, we align the two THIs by DP-matching. Then we use matching result to make texture mapping onto building model surface.]]></description>
      <pubDate>Mon, 25 Jan 2010 08:08:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/908420</guid>
    </item>
    <item>
      <title>Space-Time Accessibility Measures for Evaluating Mobility-Related Social Exclusion of the Elderly</title>
      <link>https://trid.trb.org/View/890378</link>
      <description><![CDATA[Towards aged society, it is important to provide better mobility and accessibility for the elderly and disabled people, so that they can live their independent lives in community. The elderly have a wide range of constraints on participating in out-of-home activities; for example, physical disadvantages, keeping regular lifestyles for their health and entrenched habits, limited space-time areas of activity engagement for both safety problems and limited ability of information acquisition, and monetary budget constraint. In addition, people who cannot drive a car depend more on public transport service and need their household members’ help when they go out. Therefore, their choice sets of feasible activity-travel patterns are strongly restricted by these constraints. This is regarded as one of the mobility-related “social exclusion” problems. It should be useful to analyze the feasibility of activity participation of the elderly under personal and environmental constraints they face in their daily lives. The objectives of this study are (1) to propose and validate a method for evaluating mobility-related social exclusion based on the concept of space-time accessibility and (2) to investigate the elderly people’s constraints in their activity schedules by examining how they adjust activity schedules when participating in out-of-home activities. Space-time accessibility measures represent the ease to participate in out-of-home activities, considering possibility of activity engagement under space-time constraints. Data required for the analysis consist of activity schedules of individuals, transportation network, and locations and opening hours of activity opportunities. In December 2005, we conducted a questionnaire survey to collect information on activity diaries and scheduling adjustment for participating in a medical care activity at two general hospitals. The respondents were people of 65 years and over who came to either of the two hospitals in Akita city. The number of samples was 70. Based on space-time constraints of daily in-home mandatory and maintenance activities, space-time accessibility measures to participating in a medical care activity at the hospitals were calculated. Information on spatial distribution of the elderly population from the Population Census data was used for analysis of accessibility evaluation in urban scale. Geographic information system (GIS) was used for data management and representation of the results. From a series of analyses, we identified a considerable gap in accessibility between individuals with and without car, and between urban and suburban areas. It was also found that the elderly adjusted their activity schedules (adjustment in start time, duration of activities) to participate in a medical care activity as compared to their daily regular schedules. The proposed method makes it possible to evaluate the impacts of policy measures for mitigating mobility-related social exclusion, which incorporate not only the improvement of transportation services, but also the improvement of activity opportunities and household activity schedules.]]></description>
      <pubDate>Fri, 19 Jun 2009 09:28:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/890378</guid>
    </item>
    <item>
      <title>Human Interaction Spaces Under Uncertainty</title>
      <link>https://trid.trb.org/View/800940</link>
      <description><![CDATA[Rigid activity schedules and pressure of time can strongly influence the determination of a meeting place and time. When several uncertain determinants need to be taken into account, joint activity planning becomes a complex issue. In this respect, a cross-pollination of Hägerstrand’s time geography and Pawlak’s rough set theory yields a fruitful foundation for analyzing multiple agents’ travel spaces under uncertainty. This paper reports on an attempt to analyze the effects of uncertain spatiotemporal settings on the determination of interaction spaces. The aim is to provide a better understanding of the uncertainty component of constraints to support agents pointing out a feasible meeting place while respecting individuals’ fixed activity programs. The concept of rough space–time prisms and their effect on current space–time accessibility measures is presented. The paper focuses on three types of uncertainty: temporal, spatial, and speed.]]></description>
      <pubDate>Wed, 02 May 2007 13:02:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/800940</guid>
    </item>
    <item>
      <title>Integrated Spatiotemporal GIS System for Exploring Intrahousehold Interactions</title>
      <link>https://trid.trb.org/View/801759</link>
      <description><![CDATA[Activity-based travel demand modeling has long focused on individual scheduling decisions. However, household members do not make their activity/travel decisions in isolation from other members of their household. Rather, they interact in many ways; therefore, their activity/travel patterns are inter-dependent. An explicit recognition of joint episodes is crucial to the development of a new generation of activity-based models, whose performance will be improved in capturing or predicting responses to policy changes in land-use and transportation system. This paper develops an integrated spatio-temporal GIS system to support exploration of intra-household interactions. This framework includes two toolkits.  One is called “Space-Time Coincidence Analyst”, which helps identify joint activity/travel behavior undertaken by household members. The core of this toolkit is that we develop a set of flexible criteria for classifying joint episodes. The second toolkit is called “Space-Time Path Visualizer”, which not only helps display each individual space-time path for each household member, but also visualizes joint activities undertaken by any two household members. Our system is the first integrated household-based spatio-temporal GIS model, which combines functions of analysis and visualization of intra-household interactions together in a complimentary way. At the same time, these two toolkits can be used individually, which means that the user can choose using either one of them or both at any sequence, depending on their research goals. Furthermore, our framework is not limited to any specific survey data set. In other words, it can be applied to various surveys in different regions.]]></description>
      <pubDate>Wed, 25 Apr 2007 13:44:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/801759</guid>
    </item>
    <item>
      <title>CONDITIONAL SIMULATION OF A CLASS OF NONSTATIONARY SPACE-TIME RANDOM FIELDS</title>
      <link>https://trid.trb.org/View/656271</link>
      <description><![CDATA[This paper first addresses the problem of conditionally simulating stationary, space-time, Gaussian random fields.  A method developed for quadrant-symmetric, stationary, space-time fields is extended to account for the imaginary part of the complex cross-spectrum.  The paper then addresses the case of amplitude- and frequency-modulated (AFM) nonstationary space-time fields.  The evolutionary spectral density and cross-correlation structure of such a class of nonstationary random fields are analyzed in terms of the envelope and frequency modulation functions.  A method for the conditional simulation of AFM space-time fields is advanced.  The AFM nonstationary fields are mapped to a domain where the conditional simulation is performed as for stationary, space-time fields.  Examples are given to illustrate the use and capabilities of the method including applications to the simulation of earthquake ground motions.]]></description>
      <pubDate>Thu, 22 Jun 2000 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/656271</guid>
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