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A Skeptic Embrace of Simulation
Funcke, Alexander (Stockholm University)
Skeptics tend not to be the first to jump on the next band- wagon. In quite a few areas of science, simulations and Com- plex Adaptive Systems (CAS) has been the bandwagon in question. This paper intends to reach out to the skeptics and convince them to hop-on; take over the controls and make the wagon do a U-turn and aim for the established scientific theories. The argument is that simulation techniques, such as Agent- Based Modelling (ABM), may possibly be epistemically problematic as one sets out to strongly corroborate theories concerned with our overly complex real world. However, us- ing the same techniques to explore the robustness of (or to falsify) existing abstract and idealised mathematical models will be to be epistemically uncomplicated. This allows us to study the effects of reintroduction of real-world traits, such as autonomy and heterogeneity that was previously sacrificed for mathematical tractability.
Fractally Finding the Odd One Out: An Analogical Strategy For Noticing Novelty
McGreggor, Keith (Georgia Institute of Technology) | Goel, Ashok (Georgia Institute of Technology)
The Odd One Out test of intelligence consists of 3x3 matrix reasoning problems organized in 20 levels of difficulty. Addressing problems on this test appears to require integration of multiple cognitive abilities usually associated with creativity, including visual encoding, similarity assessment, pattern detection, and analogical transfer. We describe a novel fractal strategy for addressing visual analogy problems on the Odd One Out test. In our strategy, the relationship between images is encoded fractally, capturing important aspects of similarity as well as inherent self-similarity. The strategy starts with fractal representations encoded at a high level of resolution, but, if that is not sufficient to resolve ambiguity, it automatically adjusts itself to the right level of resolution for addressing a given problem. Similarly, the strategy starts with searching for fractally-derived similarity between simpler relationships, but, if that is not sufficient to resolve ambiguity, it automatically shifts to search for such similarity between higher-order relationships. We present preliminary results and initial analysis from applying the fractal technique on nearly 3,000 problems from the Odd One Out test.
Representing and Reasoning About Spatial Regions Defined by Context
Klenk, Matthew (Palo Alto Research Center) | Hawes, Nick (University of Birmingham) | Lockwood, Kate (California State University, Monterey Bay)
In order to collaborate with people in the real world, cognitive systems must be able to represent and reason about spatial regions in human environments. Consider the command "go to the front of the classroom". The spatial region mentioned (the front of the classroom) is not perceivable using geometry alone. Instead it is defined by its functional use, implied by nearby objects and their configuration. In this paper, we define such areas as context-dependent spatial regions and propose a method for a cognitive system to learn them incrementally by combining qualitative spatial representations, semantic labels, and analogy. Using data from a mobile robot, we generate a relational representation of semantically labeled objects and their configuration. Next, we show how the boundary of a context-dependent spatial region can be defined using anchor points. Finally, we demonstrate how an existing computational model of analogy can be used to transfer this region to a new situation.
The Investigation of Problems of Healing of Cracks by Injection of Fluids with Inclusions in Various Thermoelastic Media
Bagdoev, Alexander (Institute of Mechanics NAS of Armenia) | Manukyan, Gohar (Institute of Mechanics NAS of Armenia)
The purpose of this paper is to investigate the problem of healing of cracks in infinite thermo elastic surroundings by currents of fluids with inclusions. The process of healing is result of growing of layer of sediments on crack’s surfaces due to transverse diffusion currents of crystalline inclusions which leads to closing of crack. The obtained analytical formulae for vertical displacements of boundary of crack and graphs of it allow determine coordinates and time moments of zero width of crack, i.e. process of healing of crack. The applications to biological and technological problems when as mixture is used fluid with camphor crystalline as well as to geothermal cracks with fluid currents containing silicon crystalline with application to geophysics, and results of calculations also can be used in meso mechanics. The investigation of obtained curves of dependence of times and coordinates of healing of cracks processes is done as by deterministic treatment, as well as on account of possible randomness, taking places for micro sizes of cracks by methods of nonlinear wave dynamics. The main methods of investigation of healing problem for cracks are taking into account of thermo diffusion and thermo elasticity stresses and displacements effects and trybological supplements in boundary condition on the cracks., and solution of posed problem of thermo elasticity by method of integral transformations of Laplace and Fourier, method of Winner-Hopf. The analytical solution for displacements of mentioned unsteady plane problem is brought to effective Smirnov-Sobolev form. The calculations of integrals for displacements on crack surface are carried out for number of typical constants of media and parameters of biomechanical, technological, geophysical, nanophysics problems. Furthermore there are carried out applications of methods of nonlinear wave dynamics to finding of probabilities of processes of healing of cracks.These analytic and numerical methods based on dynamic thermo-elasticity approximation on account of diffusion currents of inclusions in fluid mixture in cracks allow determine time and coordinate of closing of cracks. Besides are examined obtained curves of healing processes by methods of nonlinear waves dynamics. These methods can be applied also to extremely processes of transition from meso level defects to synchronized processes of generation of macro cracks and fracture.
Geographic Distribution of Disruptions in Weighted Complex Networks: An Agent-Based Model of the U.S. Air Transportation Network
Earnest, David C. (Old Dominion University)
International networks, although highly efficient, may produce surprising threshold effects that shift costs to geographically distant locations. International utility, transportation, and information networks facilitate the efficient flow of information, energy, goods and people. These networks exhibit a scale-free network structure with a few large “hubs”. Yet their efficiency belies their lack of robustness. Because such networks transcend national boundaries, furthermore, disruptions to the network in one geographic region may have profound economic and national security costs for countries in another region. To illustrate how complex networks may transmit costs among countries, this paper builds an agent-based model (ABM) of the international air transportation system. The ABM employs a genetic algorithm to identify “small” disruptions that produce cascading network failures. The study makes two contributions. First, it demonstrates how some complex networks evolve into network structures that trade off robustness for efficiency. Second, it illustrates how researchers can combine agent-based modeling, evolutionary computation, and network analysis to simulate differing failure modes for global networks. This convergence of simulation methodologies characterizes the emerging field of computational social science.
Modal Verbs in the Common Ground: Discriminating Among Actual and Nonactual Uses of Could and Would for Improved Text Interpretation
Moon, Lori (University of Illinois Urbana Champaign)
Modal verbs occur in contexts which convey information about non-actual states of affairs as well as in contexts which convey information about the actual world of the discourse. Modeling the semantic interpretation of non-actual states of affairs is notoriously complicated, sometimes requiring modal logic, belief revision, non-monotonic reasoning, and multi-agent autoepistemic models. This work presents linguistic features which disambiguate those instances of the past tense modal verbs `could’ and `would’ which occur in contexts where the proposition in the scope of the modal is not true in the actual world of the discourse from those instances which presuppose or entail that an event in their scope occurred in the actual world of the discourse. It also illustrates the complexity of the role of modal verbs in semantic interpretation and, consequently, the limitations of state of the art inference systems with respect to modal verbs. The features suggested for improving modal verb interpretation are based on the analysis of corpus data and insights from the linguistic literature.
Ziggurat: Steps Toward a General Episodic Memory
Faltersack, Zachary (University of Portland) | Burns, Brian (University of Portland) | Nuxoll, Andrew (University of Portland) | Crenshaw, Tanya L. (University of Portland)
Evidence indicates that episodic memory plays an important role in general cognition. A modest body of research exists for creating artificial episodic memory systems. To date, research has focused on exploring their benefits. As a result, existing episodic memory systems rely on a small, relevant memory cue for effective memory retrieval. We present Ziggurat, a domain-independent episodic memory structure and accompanying episodic learning algorithm that learns the temporal context of recorded episodes. Ziggurat's context-based memory retrieval means that it does not have to rely on relevant agent cues for effective memory retrieval; it also allows an agent to dynamically make plans using past experiences. In our experimental trials in two different domains, Ziggurat performs as well or better than an episodic memory implementation based on most other systems.
Automatic Verification and Validation of a CAS Simulation of an Intensive Care Unit
Eichelberger, Christopher (The University of North Carolina at Charlotte) | Hadzikadic, Mirsad (The University of North Carolina at Charlotte) | Gajic, Ognjen (The Mayo Clinic) | Li, Guangxi (The Mayo Clinic)
Complex adaptive systems (CAS) promise to be useful in modeling and understanding real-world phenomena, but remain difficult to validate and verify. The authors present an adaptive, tool-chain-based approach to continuous validation and verification that allows the subject matter experts (SMEs) and modelers to interact in a useful manner. A CAS simulation of the ICU at the Mayo Clinic is used as a working example to illustrate the method and its benefits.
Evaluating Integrated, Knowledge-Rich Cognitive Systems
Jones, Randolph M. (Soar Technology) | Robert E. Wray, III (Soar Technology)
This paper argues the position that an essential approach to the advancement of the state of the art in cognitive systems is to focus on systems that deeply integrate knowledge representations, cognitive capabilities, and knowledge content. Integration is the path to aggregating constraints in ways that improve the science of cognitive systems. However, evaluating the role of knowledge among these constraints has largely been ignored, in part because it is difficult to build and evaluate systems that incorporate large amounts of knowledge. We provide suggestions for evaluating such systems and argue that such evaluations will become easier as we come closer to applying usefully new, integrated learning mechanisms that are capable of acquiring large and effective knowledge bases.
Building Common Ground and Interacting through Natural Language
Murugesan, Arthi (Naval Research Laboratory) | Frost, Wende K. (Naval Research Laboratory) | Brock, Derek (Naval Research Laboratory) | Perzanowski, Dennis (Naval Research Laboratory)
Natural language is a uniquely convenient means of communication due to, among its other properties, its flexibility and its openness to interpretation. These properties of natural language are largely made possible by its heavy dependence on context and common ground. Drawing on elements of Clark’s account of language use, we view natural language interactions as a coordination problem involving agents who work together to convey and thus coordinate their interaction goals. In the modeling work presented here, a sequence of interrelated modules developed in the Polyscheme cognitive architecture is used to implement several stages of reasoning the user of a simple video application would expect an addressee—ultimately, the application—to work through, if the interaction goal was to locate a scene they had previously viewed together.