visual programming of intelligent agents for virtual archaeology

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  • 7/28/2019 Visual programming of intelligent agents for virtual archaeology


    Visual programming of intelligent agents for virtualarchaeology


    Abstract Historians and archaeologists have used virtual worldsin their research to provide them with a laboratory to testhypothesis based on excavation data, site pictures, historicdocuments and images, and similar elements. Known as virtualarchaeology, this new set of methods to visualise historic sites hasso far focused on depicting the architecture and artefacts foundon the sites. More recently, however, historians andarchaeologists have employed virtual worlds to also study socialinteraction in those sites, thus increasing the level of immersionfor researchers, students, and visitors, but also presenting newchallenges: simulation of behaviour and social interaction

    commonly uses intelligent agents, an area extensively researched,but which requires relatively advanced programming skills whichmight not be universally available to historians and archeologists.Work done for this thesis will attempt to provide them withsimple, visual tools to allow researchers to describe profiles andrules enabling the simulation of social interaction inside heritagesites recreated in virtual worlds using Second Life/OpenSimulator technology.

    Keywords: Virtual archaeology; Second Life; OpenSimulator;visual programming; intelligent agents


    Virtual archaeology is a field of research that employs

    techniques and methods used by historians and archaeologists,using computer-generated models, to visualise culturalartefacts and heritage sites [1]. These days, most of thosemodels are done in 3D and have become increasingly popularas the cost of sufficiently powerful hardware to render 3Dsynthetic environments dropped to affordable levels.

    Historically, this area of computer science focused mostlyon the technology to render 3D artefacts and heritage sites[2].Research focused on realism and immersive interfaces, usuallyusing haptic devices, and the goal was to provide an experienceof the past that was as realist as possible. This captured theattention of the movie and games software industry which wereinterested in the degree of realistic detail provided by thetechnology employed on the models. On the educational side,

    most of the installations were made in museums or similarenvironments, where whole rooms could be dedicated to therequired machinery providing the illusion of walking acrossheritage sites; more light-weight solutions, using portablehelmets and augmented reality glasses, started to appear onsome historical sites, providing additional information tovisitors.

    However, Frisher reports that the focus of those initialattempts was on the spectacularity of the technology, and noton its historical accuracy. Frequently, historians andarcheologists were not part of the research teams, which

    included mostly computer experts, software engineers, and 3Dmodellers. Several decisions were made during the creation ofthe models that were poorly documented (or not at all) and thecriteria were mostly favouring an interesting, quasi-cinematographic experience, regardless of the actual level ofhistorical accuracy of the models. Additionally, the costs were

    prohibitive for most installations, mostly due to the hardwarerequirements, many of which were still experimental

    prototypes, custom-built for a specific type of experience, andnot easily available.

    This lead historians and archaeologists, recognising theimmense potential of 3D computer models for their research, tostart proposing research methodologies focused on thehistorian/archaeologist (one of those methodologies is detailedin the London Charter [3], but others exist). These documentsspecified guidelines for adding documented justifications of allmodelling decisions made during a virtual archaeology project,described metadata types to identify the 3D objects used in the

    project, and suggested methods to keep track of successiverevisions and versions of the project. The adoption of such amethod would allow researchers to validate models as to theirhistoric accuracy, by allowing further researchers to build theirown models based on the documentation provided, andeventually confirm or reject the model independently.

    Thus, current research in virtual archaeology tends to havehistorians and/or archaeologists as project leaders, withtechnically qualified researchers contributing to the projectdevelopment under their guidance. This lead to historicallymore correct models, which, however, might be visually lessattractive.

    The new model is not free of problems. On one hand,historians might not be technologically proficient enough tounderstand how to use and employ appropriate computerhardware and software to model the heritage site [4] or havedifficulties in conveying what they wish to create to thetechnical team, overestimating the capabilities of current-generation hardware and software. Research teams and

    technical teams might be separated, working in isolation ofeach other, and only with difficulty manage to complete aproject that is fulfilling to both and is also historicallyvalidated. Fortunately, such examples abound (Rome Reborn isa typical example of a successful project [5]).

    Since many of those projects might not be so visuallyappealing as the first-generation projects, the movie and gameindustry have been more reluctant to adopt them, preferringinstead to continue to use historically inaccurate models, sincethey have a different audience in mind entertainment andnot necessarily education. This raises the question of how to

  • 7/28/2019 Visual programming of intelligent agents for virtual archaeology


    distribute the results of a virtual archaeology project once all3D models have been created; very often, the costs ofdistribution have to be included in the project as well.


    A. Solving distribution problems, but raising new ones

    Virtual worlds are synthetic computer-generated 3Denvironments used simultaneously by thousands or evenhundreds of thousands of users, each of which represented bytheir avatar, and who can interact, in real time, with thesimulated environment. These allow for the same model to beinstantly visualised by several users sharing the same virtualspace, and are thus appropriate both for entertainment andeducational purposes (e.g. a guided tour to Ancient Rome,which can be visited alone or in a group with or without aguide [6]).

    Among all virtual worlds, Second Life, and its opensource counterpart, OpenSimulator, has gained popularityamong the research community. Second Life has around twentymillion users registered with their avatars, and all the displayedcontent is created by its users. 3D content is created and

    visualised in real-time; no special external software is required,since the open source Second Life Viewer includes all buildingand programming tools to create content, which appearsimmediately for all users in the same scene, without requiringrendering. Content is created collaboratively: several users canwork on the same models at the same time, and each will seeimmediately the results of adding further content. Theunderlying system will provide object persistence by storingcontent on the so-called grid servers, which are hosted by thecompany Linden Lab in the case of the Second Life Grid acollection of several servers running a single, visuallycontiguous virtual world. While creating appealing contentrequires some skill and talent, the creation tools were designedwith amateurs in mind. All this has contributed to itswidespread use as a residential entertainment platform, a

    business tool, an education platform, and as a research andsimulation platform for many different areas; virtualarchaeology neatly fitted in the kind of possible uses forSecond Life.

    When working on a virtual archaeology project, teams canlog in from geographically distinct areas but workcollaboratively on the same virtual site; due to the nature ofimmediate visualisation of the created content, historians canuse Second Life as a research lab: modelling heritage sites

    based on researched documentation and images and deployinga possible virtual reconstruction of the site. Researchers canimmediately validate their assumptions visually and proceed tocorrect them. Changing models or moving it to different places

    is very easy to accomplish even for an unskilled user; bycollaborating with skilled 3D modellers, historians can, in thevirtual world environment, using communication tools likeVoice over IP (VoIP) or simple text chat, instruct technicians to

    position content accurately. This interactive mode of closecollaboration allows several hypothesis about the layout of theheritage site to be quickly evaluated and approve or rejectthem. Simultaneously, while the site is being reconstructed, thearea can be opened to visitors; thus, it is possible todynamically adapt and change the whole site, or start with anarea but expand it gradually, while the site is being activelyvisited. Virtual worlds like Second Life neatly exploit this

    facility to distribute content to a relatively large audience veryeasily; unlike other platforms, it eliminates long preparation

    phases before modelling begins, followed by content actuallygetting modelled using specialised and expensive 3D tools likeMaya, 3DS, Blender, or others; 3D models get rendered (whichusually takes a lot of time); digital video footage is capturedand then edited; and finally, the resulting images are published,

    burned to DVDs, or sent to websites for streaming. Anycorrections required under a more traditional approach take alot of time until a new version is produced and distributed tothe end users. By contrast, using virt