Large Worlds Research Articles

Enhanced waypoint graph for surface and volumetric path planning in virtual worlds

Our research focuses on the problem of path planning in 3D virtual world applications. The characters we consider are heterogeneous, as they have different sizes, and can perform surface or volumetric motion. In this paper, we propose an enhanced waypoint graph, which consists of point nodes equipped with radius, as well as edges connecting those nodes. Each edge is labeled with the motion type it can support. Given a polygon soup representation of a virtual world, the proposed algorithm starts by subdividing the virtual world into regions. This enables us to process large virtual worlds. Each region is then locally voxelized, one at a time. Two kinds of waypoints are generated: local waypoints using corner detection on the voxelization, and border waypoints at the region boundary. Waypoints are then sparsely connected to form a local waypoint graph, and local graphs are finally connected via the border waypoints to create the final global enhanced waypoint graph. To plan paths between arbitrary points using this graph, the points are connected to the graph using nearest neighbor search and traversability test, then Dijkstra/A* algorithm is used to calculate the final path, taking into account the appropriate size and motion type.

Implementing artificial intelligence: a generic approach with software support

In computer games, one of the eminent trends is to create large virtual worlds with numerous non-player characters. Usually their artificial intelligence (AI) is implemented by scripting, which can be a burden for the application developers involved. This paper suggests an approach facilitating designing AI functionalities and striving to reduce, via software tool support, the amount of hand-written AI script code needed. Our approach is suitable for, e.g., creating autonomous agents with personal characteristics, capable of behaving in a natural manner. For instance, the goal-oriented agent paradigm can be applied easily with the approach. The definitions needed are written using a script language. Therefore, the agent configurations can be tested rapidly. We have extended an existing AI environment and created a script framework for implementing general-purpose AIs. Moreover, we have implemented software tools capable of generating script code for helping in the AI structure design and for simplifying the actual code-writing task. For demonstrating the applicability of our approach, three example scenarios specialized from the framework are presented.

Distinct Clusterings and Characteristic Path Lengths in Dynamic Small-World Networks with Identical Limit Degree Distribution

Many real-world networks belong to a particular class of structures, known as small-world networks, that display short distance between pair of nodes. In this paper, we introduce a simple family of growing small-world networks where both addition and deletion of edges are possible. By tuning the deletion probability q t , the model undergoes a transition from large worlds to small worlds. By making use of analytical or numerical means we determine the degree distribution, clustering coefficient and average path length of our networks. Surprisingly, we find that two similar evolving mechanisms, which provide identical degree distribution under a reciprocal scaling as t goes to infinity, can lead to quite different clustering behaviors and characteristic path lengths. It is also worth noting that Farey graphs constitute the extreme case q t ≡0 of our random construction.

Multi‐core scalable and efficient pathfinding with Parallel Ripple Search

ABSTRACTGame developers are often faced with very demanding requirements on huge numbers of agents moving naturally through increasingly large and detailed virtual worlds. With the advent of multi‐core architectures, new approaches to accelerate expensive pathfinding operations are worth being investigated. Traditional single‐processor pathfinding strategies, such as A* and its derivatives, have been long praised for their flexibility. We implemented several parallel versions of such algorithms to analyze their intrinsic behavior, concluding that they have a large overhead, yield far from optimal paths, do not scale up to many cores or are cache unfriendly. In this article, we propose Parallel Ripple Search, a novel parallel pathfinding algorithm that largely solves these limitations. It utilizes a high‐level graph to assign local search areas to CPU cores at “equidistant” intervals. These cores then use A* flooding behavior to expand towards each other, yielding good “guesstimate points” at border touch on. The process does not rely on expensive parallel programming synchronization locks but instead relies on the opportunistic use of node collisions among cooperating cores, exploiting the multi‐core's shared memory architecture. As a result, all cores effectively run at full speed until enough way‐points are found. We show that this approach is a fast, practical and scalable solution and that it flexibly handles dynamic obstacles in a natural way. Copyright © 2012 John Wiley & Sons, Ltd.

Flocking techniques to naturally support navigation in large and open virtual worlds

This paper proposes and explores the use of flocking techniques to naturally support navigation in large and open virtual environments. The proposed approach comprises both a flocking algorithm (which simulates the behavior of a flock of virtual beings) and a control algorithm (which manages the navigation information and parameterizes the flocking behavior). The model was developed and evaluated through a user study which investigated whether the addition of the proposed model has an effect on the user experience when exploring a virtual environment. In the research the experiment group explored a virtual environment where the proposed flocking model was added to suggest places to visit. The participants were not informed about the guiding abilities of the virtual animals. The control group explored the same virtual environment without the animal flock. The impact of both cases was compared. The results indicate that the proposed model is adequate to suggest places to visit in large and open virtual worlds.

Innovation in virtual social networks: the widespread of new electronic currencies and the emergence of a new category of entrepreneurs

The internet network hosts an increasing number of large synthetic worlds. These virtual worlds exhibit most of the characters we associate with the real world like interpersonal relationships, economic transactions, production of goods and services, political institutions? Inside these synthetic worlds, new economic behaviours can be studied and new entrepreneurs emerge. By focusing on the widespread of new private electronic currencies, this paper shows first the main benefits for e-money users of entering in a community of payments. Second, the economic behaviour of electronic money (e-money) users and the network externalities effects are studied. Thirdly, the phenomenon of the emergence of a new category of entrepreneurs specialised in e-money creation and the regulation of a new monetary regime are exposed.

Book Reviews

Tilman Borgers of University of Michigan reviews “Rational Decisions” by Ken Binmore,. The EconLit Abstract of the reviewed work begins “Explores standard theories of choice and belief under risk and uncertainty, focusing on Bayesian decision theory. Discusses revealed preference; game theory; risk; utilitarianism; classical probability; frequency; Bayesian decision theory; epistemology; large worlds; and mathematical notes. Binmore is Professor Emeritus of Economics at University College London. Index.”

Dealing with Multiple Truths in Online Virtual Worlds

Virtual environments and online games are becoming a major market force. At the same time, the virtual property contained in these environments is being traded for real money and thus attains a real value. Although the legal issues involved with this virtual property have not yet been decided, they will have to be soon. It is foreseeable that the next generation of very large virtual worlds will carry the possibility of multiple truths existing at the same time. Under such circumstances, it will be impossible to physically protect virtual property. In order to protect virtual property, virtual environment systems will therefore have to conform to certain requirements. We analyze what these requirements are in order to either prevent cheating or at least prove a digital offence has transpired. Along with greater security, this will also simplify end user support, which is one of the major cost factors for online games.

Scalable real‐time animation of rivers

AbstractMany recent games and applications target the interactive exploration of realistic large scale worlds. These worlds consist mostly of static terrain models, as the simulation of animated fluids in these virtual worlds is computationally expensive. Adding flowing fluids, such as rivers, to these virtual worlds would greatly enhance their realism, but causes specific issues: as the user is usually observing the world at close range, small scale details such as waves and ripples are important. However, the large scale of the world makes classical methods impractical for simulating these effects. In this paper, we present an algorithm for the interactive simulation of realistic flowing fluids in large virtual worlds. Our method relies on two key contributions: the local computation of the velocity field of a steady flow given boundary conditions, and the advection of small scale details on a fluid, following the velocity field, and uniformly sampled in screen space.

Gravitational contributions to the running Yang-Mills coupling in large extra-dimensional brane worlds

We study the question of a modification of the running gauge coupling of Yang-Mills theories due to quantum gravitational effects in a compact large extra dimensional brane world scenario with a low energy quantum gravity scale. The ADD scenario is applied for a D=d+\delta dimensional space-time in which gravitons freely propagate, whereas the non-abelian gauge fields are confined to a d-dimensional brane. The extra dimensions are taken to be toroidal and the transverse fluctuation modes (branons) of the brane are taken into account. On this basis we have calculated the one-loop corrections due to virtual Kaluza-Klein graviton and branon modes for the gluon two- and three-point functions in an effective field theory treatment. Applying momentum cut-off regularization we find that for a d=4 brane the leading gravitational divergencies cancel irrespective of the number of extra dimensions \delta, generalizing previous results in the absence of extra-dimensions. Hence, again the Yang-Mills \beta-function receives no gravitational corrections at one-loop. This is no longer true in a `universal' extra dimensional scenario with a d>4 dimensional brane. Moreover, the subleading power-law gravitational divergencies induce higher-dimensional counterterms, which we establish in our scheme. Interestingly, for d=4 these gravitationally induced counterterms are of the form recently considered in non-abelian Lee-Wick extensions of the standard model -- now with a possible mass scale in the TeV range due to the presence of large extra dimensions.

Developing Countries and E-Learning Program Development

Technological advances offer new paradigms for university training. In particular, multimedia tools have strengthened the distance learning and e-learning approaches. E-Learning is a subset of two large worlds, specifically, "information technology" and "education and training." Converting a traditional course to e-learning may represent a complex endeavour, and as such it requires accurate planning, monitoring, and control to make the conversion effective and economical. In this paper, after reviewing some general concepts and components of e-learning programs, the e-learning model and guidelines for developing countries are presented. Then, the case study of the first e-University (or Virtual University) established in Iran is reported.

Comment on 'Making Decisions in Large Worlds' by Ken Binmore

In this brilliant, provocative new piece, KEN BINMORE continues in his efforts to "debayes" game theory. The current paper, given as the ADRES 2006 lecture in Marseilles, is part of a broad research agenda, where Professer BINMORE aims at refounding game the, by questioning some of its basic tenets. In this lecture, he focusses attention on the inadequacy of Bayesian reasoning to handle decision making and strategic interaction in large worlds. The distinction between small and large worlds in SAVAGES Foundation of Statistics, is hardly format or precise. A small world is a situation where the decision maker understands all the contingencies, and Bayesian decision making applies; a large world is characterized by uncertainty (about the events and their likelihood), and ambiguity. Clearly, the tools and methods of Bayesian statistics are inadequate to handle decision-making in large worlds.

Rational Decisions in Large Worlds

This paper argues that we need to look beyond Bayesian decision the, for an answer to the general problem of making national decision under uncertainty. The view that Bayesian decision theory is only genuinely valid in a small world was asserted very firmly by SAVAGE [1951] when laying down the principles of the theory in his path - breaking Foundations of Statistics. He makes the distinction between small and large worlds in a folksy way by quoting the proverbs "Look before you leap" and "Cross that bridge when you corne to it". You are in a small world if it is feasible always to look before you leap. You are in a large world if there are some bridges that you cannot cross before you corne to them.

Bayesian Foundations for Game Theory? A Comment on "Making Decisions in Large Worlds" by Ken Binmore

Bayesian Foundations for Game Theory? A Comment on "Making Decisions in Large Worlds" by Ken Binmore

Drift–diffusion in mangled worlds quantum mechanics

In Everett's many-worlds interpretation, where quantum measurements are seen as decoherence events, inexact decoherence may let large worlds mangle the memories of observers in small worlds, creating a cutoff in observable world measure. I solve a growth–drift–diffusion–absorption model of such a mangled worlds scenario, and show that it reproduces the Born probability rule closely, though not exactly. Thus, inexact decoherence may allow the Born rule to be derived in a many-worlds approach via world counting, using a finite number of worlds and no new fundamental physics.

Generating a VRML world from database contents: Illustrated by application to flood risk communication

The Virtual Reality Modelling Language (VRML) was created for visualizing interactive 3D objects and worlds over the Internet. For cartography, VRML has proved to be a useful tool for modelling reality producing 3D animations and interactive mapping. Another useful and emerging VRML capability for cartographers is database connectivity. Databases can be used to store object characteristics such as geographic coordinates, object geometry and object textures. The object characteristics stored in the database can be used to generate a VRML world. This is particularly useful for improving the efficiency of data maintenance and reducing the download rates of large VRML worlds. The main objective of this paper is to inform readers of how VRML can be generated from a database. An example of a VRML world that is being generated by the scripting language PHP from a text database will be provided. This example is a part of prototype, geographic visualization (GeoVis) tools being developed by the authors for a research project. The research project is motivated by the idea that visuals can be used alongside traditional warning methods as a way of improving flood risk communication to the public. This paper is a good starting point for those wanting to link a database to a VRML world but lack the experience in VRML and database connectivity to do so.

The Price of Bodies: A Hedonic Pricing Model of Avatar Attributes in a Synthetic World

SummaryThis paper explores a unique new source of social valuation: a market for bodies. The internet hosts a number of large synthetic worlds which users can visit by piloting a computer‐generated body, known as an avatar. Avatars can have an asset value, in that users can spend time to increase their skills; these asset values can be directly observed in online markets. Auction data for avatars from the synthetic fantasy world of EverQuest are used here to explore a number of questions involving the relative value of different body characteristics. Hedonic analysis of the auction price data suggests that the ‘level’, a game‐design metric that indicates the overall functionality or power of the avatar, is by far the most important attribute of the body. Other attributes that show significant price effects include: sex and class (i.e. being a wizard rather than warrior type of character). The male‐female price difference is interesting because there are actually no sex‐based differences in the abilities of the avatar bodies, by design. Price differences here must be caused by some other aspect of buyer preferences, ones unrelated to power or functionality of the avatar itself.

The Price of 'Man' and 'Woman': A Hedonic Pricing Model of Avatar Attributes in a Synthethic World

This paper explores a unique new source of social valuation: a market for bodies. The internet hosts a number of large synthetic worlds which users can visit by piloting a computer-generated body, known as an avatar. Avatars can have an asset value, in that users can spend time to increase their skills; these asset values can be directly observed in online markets. Auction data for avatars from the synthetic fantasy world of EverQuest are used here to explore a number of questions, especially those involving the relative value of male and female avatars. In EverQuest, about 20 percent of the avatar population is female, and there are no sex-based differences in avatar capabilities. Many avatars (about one-fourth to one-fifth of the population) are cross-gendered, being piloted by a person of the opposite sex. Nonetheless, relations between avatars are gender-based, and include chivalry, dating, and sex. Female avatars tend to be concentrated in highly sexualized Human and Elven races, with very few being present among such aesthetically-challenged races as Ogres and Trolls. Hedonic analysis of the auction price data suggests that gender labels are a less important determinant of avatar values than the level, a game-design metric that indicates the overall capabilities of the avatar. Thus, ability seems more important than sex in determining the value of a body. Nonetheless, among comparable avatars, females do sell at a significant price discount. The average avatar price is 333 dollar; the price discount for females is 40 to 55 dollar, depending on methods. The discount may stem from a number of causes, including discrimination in Earth society, the maleness of the EverQuest player base, or differences in well-being related to male and female courtship roles. We do know, however, that these differences cannot be caused by sex-based differences in the abilities of the body, since in the fantasy world of Norrath there are none.

When Worlds Collide: Quantum Probability from Observer Selection?

In Everett's many worlds interpretation, quantum measurements are considered to be decoherence events. If so, then inexact decoherence may allow large worlds to mangle the memory of observers in small worlds, creating a cutoff in observable world size. Smaller world are mangled and so not observed. If this cutoff is much closer to the median measure size than to the median world size, the distribution of outcomes seen in unmangled worlds follows the Born rule. Thus deviations from exact decoherence can allow the Born rule to be derived via world counting, with a finite number of worlds and no new fundamental physics.