This paper discusses the interim results of the AHRC RTISAD project. The project has developed and tested a range of techniques for gathering and processing reflectance transformation imaging (RTI) data. It has also assembled a detailed understanding of the breadth of RTI practice. Over the past decade the range of applications and algorithms in the broad domain of RTI has increased markedly, with current working addressing issues such as large resolution capture, 3D RTI, annotation, enhancement amongst others. Capture of RTI datasets has begun to occur in all aspects of cultural heritage and elsewhere. This has in turn prompted the development of policies and methods for managing and integrating the large quantities of data produced. The paper describes these techniques and issues in the context of a range of artefacts, including painted Roman and Neolithic surfaces, examples of ancient documents in a variety of forms, and archaeological datasets from Herculaneum, Çatalhöyük, Abydos and elsewhere. The paper also identifies ongoing software development work of value to the broad EVA community and proposes further enhancements.
This paper discusses an emerging cloud of Linked Open Data in the humanities sometimes referred to as the Graph of Ancient World Data (GAWD). It provides historical background to the domain, before gong on to describe the open and decentralised characteristics which have partially characterised its development. This is done principally through the lens of Pelagios, a collaborative initiative led by the authors which connects online historical resources based on common references to places. The benefits and limitations of the approach are evaluated, in particular its low barrier to entry, open architecture and restricted scope. The paper concludes with a number of suggestion for encouraging the adoption of Linked Open Data within other humanities communities and beyond.
The development of on-ramp metering control strategies for a freeway can be aided by the well-developed theory of linear optimal control. However, an adequate model of an appropriate form must be available. Recently developed "aggregate variable" models appear to be best suited to this purpose. In these models the freeway is sectioned into lengths of about f mi and traffic is described in terms of the aggregate variables section speed, section density, and volume. The model is used to formulate a linear regulator problem with quadratic cost for the purpose of determining a feedback control rule which returns the freeway to nominal conditions after a disturbance.The solution of the regulator problem involves considerable computation dSculty when the order of the system is large. In a large class of applications the optimal control law has a local structure which can be exploited in a computationally efficient manner to yield a suboptimal control with little loss of system performance. A new technique, the augmentation method, is presented for constructing a suboptimal control from a set of optimal controls for low-order subsystems. New results are presented which provide a rational and elegant measure for the additional cost associated with an arbitrary stabilizing suboptimal control. Additional results pertain especially to the augmentation procedure. The models and suboptimal control scheme are applied to a specific detailed design for an 8-mi segment of the San Diego Freeway in Los Angeles. Simulations are shown illustrating the effectiveness of such tratfic-responsive controls in clearing up congestion due to tratfic incidents. I I. IKTRODUCTIONK T H E PAST few years there has been interest in the surveillance and control of urban free-n-ays during periods of peak demand with the object,ive being to improve in some sense the qualit,y of vehicular ilex-through a t r a c corridor consisting of b0t.h a freeway and the parallel surface streets serving as potential alternate routes for freeway traffic. Freeway cont,rol projects in Chicago [I 3, Detroit [ 2 ] , Houst.on [3], Los Angeles [4], and other cities [ 5 ] hare shown that control procedures can improve traffic conditions.Presence detectors, especially in t,he form of inductive loops imbedded in the roadn-a.y, are in widespread use as integral parts of surveillance and control systems for monitoring freeway condit,ions [6]. At each sampling inst.a.nt the det,ector is either activated or not. act,ivated by the presence of a vehicle, and the state of the detectmom is sampled at. regular intervals, usually 1/15 s. From this sequence of state conditions the t,rafIic volume (vehicles per hour per lane) can be determined. The percent of time during which these detectors are activat,ed, termed occupancy, is typically t,aken by highway engineers as a measure of traffic behavior.Freeways are generally controlled by standard t.rafFic signals placed on the freeway entrance ramps. Traffic on the freewap can be influenced by adjusting t,he signal periods; no control is ex...
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