Decompositions of Grammar Constraints

A wide range of constraints can be compactly specified using automata or formal languages. In a sequence of recent papers, we have shown that an effective means to reason with such specifications is to decompose them into primitive constraints. We can then, for instance, use state of the art SAT solvers and profit from their advanced features like fast unit propagation, clause learning, and conflict-based search heuristics. This approach holds promise for solving combinatorial problems in scheduling, rostering, and configuration, as well as problems in more diverse areas like bioinformatics, software testing and natural language processing. In addition, decomposition may be an effective method to propagate other global constraints.Comment: Proceedings of the Twenty-Third AAAI Conference on Artificial Intelligenc

Submodular Function Maximization for Group Elevator Scheduling

We propose a novel approach for group elevator scheduling by formulating it as the maximization of submodular function under a matroid constraint. In particular, we propose to model the total waiting time of passengers using a quadratic Boolean function. The unary and pairwise terms in the function denote the waiting time for single and pairwise allocation of passengers to elevators, respectively. We show that this objective function is submodular. The matroid constraints ensure that every passenger is allocated to exactly one elevator. We use a greedy algorithm to maximize the submodular objective function, and derive provable guarantees on the optimality of the solution. We tested our algorithm using Elevate 8, a commercial-grade elevator simulator that allows simulation with a wide range of elevator settings. We achieve significant improvement over the existing algorithms.Comment: 10 pages; 2017 International Conference on Automated Planning and Scheduling (ICAPS

Order and disorder in everyday action: the roles of contention scheduling and supervisory attention

This paper describes the contention scheduling/supervisory attentional system approach to action selection and uses this account to structure a survey of current theories of the control of action. The focus is on how such theories account for the types of error produced by some patients with frontal and/or left temporoparietal damage when attempting everyday tasks. Four issues, concerning both the theories and their accounts of everyday action breakdown, emerge: first, whether multiple control systems, each capable of controlling action in different situations, exist; second, whether different forms of damage at the neural level result in conceptually distinct disorders; third, whether semantic/conceptual knowledge of objects and actions can be dissociated from control mechanisms, and if so what computational principles govern sequential control; and fourth, whether disorders of everyday action should be attributed to a loss of semantic/conceptual knowledge, a malfunction of control, or some combination of the two

Understanding temporal rhythms and travel behaviour at destinations: Potential ways to achieve more sustainable travel

This paper analyses the roles played by time in destination-based travel behaviour. It contrasts clock time's linear view of time with fragmented time, instantaneous time, fluid time and flow, time out and the multiple temporalities of tourism experiences. It explores temporal issues in a destination travel context, using qualitative techniques. Data were captured using diary photography, diary-interview method with tourists at a rural destination; their spatial and temporal patterns were captured using a purpose built smartphone app. The analysis revealed three temporal themes influencing travel behaviour: time fluidity; daily and place-related rhythms; and control of time. Three key messages emerge for future sustainable tourist destination-based travel systems. Given the strong desire for temporal fluidity, transport systems should evolve beyond clock-time regimes. Second, temporal forces favour personal modes of transport (car, walk, cycle), especially in rural areas where public transport cannot offer flexibility. Third, the car is personalised and perceived to optimise travel fluidity and speed, but is currently unsustainable. Imaginative initiatives, using new mobile media technology can offer new positive and proactive car travel, utilising spare public and private vehicle capacity. Research is needed to implement mechanisms for individualised space-time scheduling and collective vehicle use strategies. © 2013 Copyright Taylor and Francis Group, LLC

An Approach to Agent-Based Service Composition and Its Application to Mobile

This paper describes an architecture model for multiagent systems that was developed in the European project LEAP (Lightweight Extensible Agent Platform). Its main feature is a set of generic services that are implemented independently of the agents and can be installed into the agents by the application developer in a flexible way. Moreover, two applications using this architecture model are described that were also developed within the LEAP project. The application domain is the support of mobile, virtual teams for the German automobile club ADAC and for British Telecommunications

Literacy Access through Storytime: An Ethnographic Study of Public Library Storytellers in a Low-Income Neighborhood

While early literacy achievement continues to be stratified by social class in the United States, public libraries often offer programs such as “storytime” in order to bolster the literacy development of youth in their communities. The purpose of the present ethnographic study was to explore how storytellers recruited and maintained participation in this free literacy program in a lower-income neighborhood. Via participant observations, semi-structured interviews, and artifact collection, storytellers recruited new patrons to storytime by (1) appealing to community members to enter the physical space of the library and (2) appealing to library patrons to attend storytime. Once patrons attended storytime, storytellers acted in order to maintain storytime attendance by (1) facilitating meaningful learning experiences, (2) fostering enjoyment through participation, (3) developing nurturing relationships, and (4) offering flexibility in storytime expectations. By exploring a contextualized account of the work of storytellers, the findings suggest important avenues through which public programs may contribute to more equitable access to literacy learning

A Copula-Based Joint Model of Commute Mode Choice and Number of Non-Work Stops during the Commute

At the time of publication A. Portoghese, E. Spissu, and I. Meloni were at University of Cagliari, and C.R. Bhat and N. Eluru were at the University of Texas at Austin.In this paper, in the spirit of a tour-based frame of analysis, we examine the commute mode choice and the number of non-work stops during the commute. Understanding the mode and activity stop dimensions of weekday commute travel is important since the highest level of weekday traffic congestion in urban areas occurs during the commute periods. The paper employs a copula-based joint multinomial logit – ordered modeling framework in which commute mode choice is modeled using a multinomial logit formulation and the number of commute stops is modeled using an ordered response formulation. The data used in this study are drawn from the “Time use” multipurpose survey conducted between 2002 and 2003 by the Turin Town Council and the Italian National Institute of Statistics (ISTAT) in the Greater Turin metropolitan area of Italy. The results highlight the importance of accommodating the inter-relationship between commute mode choice and commute stops behavior. The results also point to the stronger effect of household responsibilities and demographic characteristics in the Italian context compared to the US context.Civil, Architectural, and Environmental Engineerin