9,640 research outputs found

    Designing the master schedule for demand-adaptive transit systems

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    Abstract Demand-Adaptive Systems (DAS) display features of both traditional fixed-line bus services and purely on-demand systems such as dial-a-ride, that is they offer demand-responsive services within the framework of traditional scheduled bus transportation. A DAS bus line serves, on one hand, a given set of compulsory stops according to a predefined schedule specifying the time windows associated with each, providing the traditional use of the transit line, without requiring any reservation. On the other hand, passengers may also issue requests for transportation between two desired, optional, stops, which induces detours in the vehicle routes. The design of a DAS line is a complex planning operation that requires to determine not only its design in terms of selecting the compulsory stops, but also its master schedule in terms of the time windows associated with the compulsory stops. Designing a DAS thus combines elements of strategic and tactical planning. In this paper we focus on determining a master-schedule for a single DAS line. We propose a mathematical description and a solution framework based on the estimation of a number of statistical parameters of the demand and the DAS line service. Results of numerical experiments are also given and analyzed

    Cracking the Code: Synchronizing Policy and Practice for Performance-Based Learning

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    Proposes a policy framework for integrating performance-based learning into the education system, synchronizing policy and practice, and ensuring collaborative state leadership and flexible federal leadership. Lists state policy issues and exemplars

    Habersham County Growth Management and Conservation Strategies

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    CP 6055 Studio, School of City and Regional PlanningGeorgia's land cover change over the past 50 years has been documented in an unprecedented study conducted by the Georgia Conservancy and the Georgia Tech Center for Spatial Planning and Visualization (CSPAV). This study has resulted in Georgia Now and Forever initiative, an ambitious undertaking to educate key decision-makers across Georgia as to the study's findings with a message that intentional, thoughtful decisions around the use of Georgia's remaining undeveloped land are inextricably linked to Georgia's future ecological and economic sustainability. item_description: Georgia's land cover change over the past 50 years has been documented in an unprecedented study conducted by the Georgia Conservancy and the Georgia Tech Center for Spatial Planning and Visualization (CSPAV). This study has resulted in Georgia Now and Forever initiative, an ambitious undertaking to educate key decision-makers across Georgia as to the study's findings with a message that intentional, thoughtful decisions around use of Georgia's remaining undeveloped land are inextricably linked to Georgia's future ecological and economic sustainability. Unsurprisingly, but important to have clearly documented, is the role low density development has played in the significant acreage conversion from agricultural land, forested land, and wetlands. These findings from past development patterns have allowed for the identification of plausible future landcover change trends, assuming business-as-usual development approaches. North Georgia is clearly in the path of major landcover change to low density developed land as metro Atlanta proceeds to "move" northward. This is also an area of significant ecological and carbon assets in the form of our mountain and valley forests, as well as agricultural lands. There is keen community interest in welcoming development-especially diverse and affordable housing choices-but alongside serious advancement in the conservation of the natural landscape. Representatives from the Habersham County, the City of Clarkesville and the property manager of a large conservation tract in the area that includes two riverfront miles of the Soquee River requested assistance from the Georgia Conservancy and Georgia Tech to consider how and where development and conservation can and should occur across their home county of Habersham. There is an understanding among this group that the very conditions that draw new residents to the area-the forests, mountains, streams-are at risk without a concerted effort to include conservation alongside land-efficient development. Given the larger situation in Georgia, the public and political will in the Clarkesville/Habersham area to pursue a larger joint development and conservation priority led to this planning process of identifying strategies for managing local resources in a sustainable way.Habersham CountyCity of Clarksvill

    Prometheus unbound: A study of the Dallas/Fort Worth Regional Airport

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    The history of the controversies in the development of the Dallas/Fort Worth Regional Airport is detailed. Present technological and organizational management problems are outlined. Maps and illustrations are included

    Development of Economic Water Usage Sensor and Cyber-Physical Systems Co-Simulation Platform for Home Energy Saving

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    In this thesis, two Cyber-Physical Systems (CPS) approaches were considered to reduce residential building energy consumption. First, a flow sensor was developed for residential gas and electric storage water heaters. The sensor utilizes unique temperature changes of tank inlet and outlet pipes upon water draw to provide occupant hot water usage. Post processing of measured pipe temperature data was able to detect water draw events. Conservation of energy was applied to heater pipes to determine relative internal water flow rate based on transient temperature measurements. Correlations between calculated flow and actual flow were significant at a 95% confidence level. Using this methodology, a CPS water heater controller can activate existing residential storage water heaters according to occupant hot water demand. The second CPS approach integrated an open-source building simulation tool, EnergyPlus, into a CPS simulation platform developed by the National Institute of Standards and Technology (NIST). The NIST platform utilizes the High Level Architecture (HLA) co-simulation protocol for logical timing control and data communication. By modifying existing EnergyPlus co-simulation capabilities, NIST’s open-source platform was able to execute an uninterrupted simulation between a residential house in EnergyPlus and an externally connected thermostat controller. The developed EnergyPlus wrapper for HLA co-simulation can allow active replacement of traditional real-time data collection for building CPS development. As such, occupant sensors and simple home CPS product can allow greater residential participation in energy saving practices, saving up to 33% on home energy consumption nationally
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