On green routing and scheduling problem

The vehicle routing and scheduling problem has been studied with much interest within the last four decades. In this paper, some of the existing literature dealing with routing and scheduling problems with environmental issues is reviewed, and a description is provided of the problems that have been investigated and how they are treated using combinatorial optimization tools

Does First Last: The Existence and Extent of First Mover Advantages on Spatial Networks

This paper examines the nature of first mover advantages on spatially-differentiated surface transportation networks. The literature on first mover advantages identifies a number of sources that explain their existence. However whether those sources exist on spatial networks, and how they play out with true capital immobility have been unanswered questions. By examining empirical examples including commuter rail and the Underground in London and roads in the Twin Cities of Minneapolis and St. Paul, first mover advantages were observed in rail stations but not in the road network. A simulation model was then constructed to replicate the growth of surface transportation networks incorporating idealized deployment decisions and to test whether the first network elements (links, nodes) remain strongest (or even strong) into the future. Simulation experiments were conducted and Spearman rank correlation tests revealed that first mover advantages exist in both nodes and links and become increasingly prominent as the network evolves due to the accumulated advantage of earlier established network elements. Simulation results also disclosed that network growth with a higher concentration of initial land uses results in stronger first mover advantages, and that the extent may vary as the topological attributes of the network change over time. The sensitivity of simulation results on model parameters are also discussed.First mover advantage, transport, land use, London Underground, London railways, network growth, induced demand, induced supply

Strengthening America's Best Idea: An Independent Review of the National Park Service's Natural Resource Stewardship and Science Directorate

NRSS requested that an independent panel of the National Academy conduct a review of its effectiveness in five core functions, its relationships with key internal stakeholders, and its performance measurement system. Among other things, the National Park Service's Natural Resource Stewardship and Science Directorate (NRSS) is responsible for providing usable natural and social science information throughout the National Park Service (NPS). NRSS leadership requested this review of the directorate's performance on five core functions, its relationships with key internal NPS stakeholders, and its performance measurement system.Main FindingsThe panel determined that NRSS is a highly regarded organization that provides independent, credible scientific expertise and technical information. The panel also found that NRSS and NPS have additional opportunities to advance natural resource stewardship throughout the Service. If implemented, the panel's eight major recommendations will: (1) help the Service respond to the parks' environmental challenges while raising public awareness about the condition of these special places; (2) strengthen NRSS as an organization; (3) promote scientifically based decision-making at the national, regional, and park levels; and (4) improve the existing performance measurement system

Unattended network operations technology assessment study. Technical support for defining advanced satellite systems concepts

The results are summarized of an unattended network operations technology assessment study for the Space Exploration Initiative (SEI). The scope of the work included: (1) identified possible enhancements due to the proposed Mars communications network; (2) identified network operations on Mars; (3) performed a technology assessment of possible supporting technologies based on current and future approaches to network operations; and (4) developed a plan for the testing and development of these technologies. The most important results obtained are as follows: (1) addition of a third Mars Relay Satellite (MRS) and MRS cross link capabilities will enhance the network's fault tolerance capabilities through improved connectivity; (2) network functions can be divided into the six basic ISO network functional groups; (3) distributed artificial intelligence technologies will augment more traditional network management technologies to form the technological infrastructure of a virtually unattended network; and (4) a great effort is required to bring the current network technology levels for manned space communications up to the level needed for an automated fault tolerance Mars communications network

ADS pilot program Plan

The Applications Data Service (ADS) is a system based on an electronic data communications network which will permit scientists to share the data stored in data bases at universities and at government and private installations. It is designed to allow users to readily locate and access high quality, timely data from multiple sources. The ADS Pilot program objectives and the current plans for accomplishing those objectives are described

Joint Network Function Placement and Routing Optimization in Dynamic Software-defined Satellite-Terrestrial Integrated Networks

Software-defined satellite-terrestrial integrated networks (SDSTNs) are seen as a promising paradigm for achieving high resource flexibility and global communication coverage. However, low latency service provisioning is still challenging due to the fast variation of network topology and limited onboard resource at low earth orbit satellites. To address this issue, we study service provisioning in SDSTNs via joint optimization of virtual network function (VNF) placement and routing planning with network dynamics characterized by a time-evolving graph. Aiming at minimizing average service latency, the corresponding problem is formulated as an integer nonlinear programming under resource, VNF deployment, and time-slotted flow constraints. Since exhaustive search is intractable, we transform the primary problem into an integer linear programming by involving auxiliary variables and then propose a Benders decomposition based branch-and-cut (BDBC) algorithm. Towards practical use, a time expansion-based decoupled greedy (TEDG) algorithm is further designed with rigorous complexity analysis. Extensive experiments demonstrate the optimality of BDBC algorithm and the low complexity of TEDG algorithm. Meanwhile, it is indicated that they can improve the number of completed services within a configuration period by up to 58% and reduce the average service latency by up to 17% compared to baseline schemes.Comment: Accepted by IEEE Transactions on Wireless Communication

The 1990 progress report and future plans

This document describes the progress and plans of the Artificial Intelligence Research Branch (RIA) at ARC in 1990. Activities span a range from basic scientific research to engineering development and to fielded NASA applications, particularly those applications that are enabled by basic research carried out at RIA. Work is conducted in-house and through collaborative partners in academia and industry. Our major focus is on a limited number of research themes with a dual commitment to technical excellence and proven applicability to NASA short, medium, and long-term problems. RIA acts as the Agency's lead organization for research aspects of artificial intelligence, working closely with a second research laboratory at JPL and AI applications groups at all NASA centers

'Sense and respond' and 'autonomic' logistics: a review of US and UK developments

Until recently, platform-based, logistics applications required data to be physically downloaded and transferred between systems so that analysis could estimate the status of key components. In both the Sense and Respond Logistics (S&RL) and Autonomic Logistics (AL) systems, prognostics have been added to monitoring functions, effectively extending the reach of Combat Service Support (CSS). The scope the supply chain has also been expanded with the potential inclusion of some classes of supply within the AL approach. The real time and predictive aspects are relatively new logistics developments facilitated by the real-time communication of data while platforms are in operation. While the (Australian) Military Integrated Logistics Information System (MILIS) proposes to extend the reach of supply chain information to sub-unit level, it falls short of crossing the gap to link Health and Usage Monitoring System (HUMS), platform-based, data into the logistics continuum to provide end-to-end visibility, a foxhole-to-factory-to-foxhole perspective, of the supply chain. This paper will review developments in recent military applications of Autonomic Logistics and Sense & Respond Logistics in the United States Defense Forces and the military in the UK while also considering a selection of Australian Defence Force programs. It will state the case for application of Autonomic Logistics and Sense & Respond Logistics to the ASLAV and Bushmaster platforms, in a similar fashion to those employed in the US and the UK, as a source of accurate and up-to-date CSS information for the various levels of command