Argument Graph Research Articles

Argument graph as a tool for promoting collaborative online reading

AbstractThis study explored how the construction of an argument graph promotes students' collaborative online reading compared to note‐taking. Upper secondary school students (n = 76) worked in pairs. The pairs were asked to search for and read source material on the Web for a joint essay and either construct an argument graph or take notes during online reading. The data consist of transcription protocols of student pairs' discussions and joint essays. The study indicated that argument graphs may be useful tools when teachers want students to pay attention to the argumentative content of online sources and to consider relations between arguments. Additionally, with argument graphs, teachers can support students' post‐reading activities, such as source‐based argumentative writing.

Using argumentation to reason about trust and belief

Trust is a mechanism for managing the uncertainty about autonomous entities and the information they store, and so can play an important role in any decentralized system. As a result, trust has been widely studied in multi-agent systems and related fields such as the semantic web. Here, we introduce a formal system of argumentation that can be used to reason using information about trust. This system is described as a set of graphs, which makes it possible to combine our approach with conventional representations of trust between individuals where the relationships between individuals are given in the form of a graph. The resulting system can easily relate the grounds of an argument to the agent that supplied the information, and can be used as the basis to compute Dungian notions of acceptability that take trust into account. We explore some of the properties of these argumentation graphs, examine the computation of trust and belief in the graphs and illustrate the capabilities of the system on an example from the trust literature.

Instantiating abstract argumentation with classical logic arguments: Postulates and properties

In this paper we investigate the use of classical logic as a basis for instantiating abstract argumentation frameworks. In the first part, we propose desirable properties of attack relations in the form of postulates and classify several well-known attack relations from the literature with regards to the satisfaction of these postulates. Furthermore, we provide additional postulates that help us prove characterisation results for these attack relations. In the second part of the paper, we present postulates regarding the logical content of extensions of argument graphs that may be constructed with classical logic. We then conduct a comprehensive study of the status of these postulates in the context of the various combinations of attack relations and extension semantics.

Teaching Adverse Selection at the Principles of Economics Level

The paper proposes a framework for teaching adverse selection at the principles of economics level based on simple graphical and numerical arguments. The proposed approach is useful for putting the emphasis on the beliefs of individuals about the behavior of others and for considering thin markets and market vanishing as outcomes of dynamic processes.

Teaching a process model of legal argument with hypotheticals

The research described here explores the idea of using Supreme Court oral arguments as pedagogical examples in first year classes to help students learn the role of hypothetical reasoning in law. The article presents examples of patterns of reasoning with hypotheticals in appellate legal argument and in the legal classroom and a process model of hypothetical reasoning that relates them to work in cognitive science and Artificial Intelligence. The process model describes the relationships between an advocate's proposed test for deciding a case or issue, the facts of the hypothetical and of the case to be decided, and the often conflicting legal principles and policies underlying the issue. The process model of hypothetical reasoning has been partially implemented in a computerized teaching environment, LARGO ("Legal ARgument Graph Observer") that helps students identify, analyze, and reflect on episodes of hypothetical reasoning in oral argument transcripts. Using LARGO, students reconstruct examples of hypothetical reasoning in the oral arguments by representing them in simple diagrams that focus students on the proposed test, the hypothetical challenge to the test, and the responses to the challenge. The program analyzes the diagrams and provides feedback to help students complete the diagrams and reflect on the significance of the hypothetical reasoning in the argument. The article reports the results of experiments evaluating instruction of first year law students at the University of Pittsburgh using the LARGO program as applied to Supreme Court personal jurisdiction cases. The learning results so far have been mixed. Instruction with LARGO has been shown to help law student volunteers with lower LSAT scores learn skills and knowledge regarding hypothetical reasoning better than a text-based approach, but not when the students were required to participate. On the other hand, the diagrams students produce with LARGO have been shown to have some diagnostic value, distinguishing among law students on the basis of LSAT scores, posttest performance, and years in law school. This lends support to the underlying model of hypothetical argument and suggests using LARGO as a pedagogically diagnostic tool.

Relational Modeling Relevance and Business Engineering Context

Even today, in many debates concerning the extension of model support to model complexity of the real world, one of the most cited of systems drawbacks is their flatness. The proponents of this vision set out the idea that the concepts proposed by the model do not supply the right constructors to express the abstractions of business reality that is modeled. If we want to demonstrate if these points of view are indeed invalid, looking at a simple relational diagram we don't get much reliable graphical arguments. Nevertheless, we believe that counting on graphical reasons converted in semantic issues constitutes, in fact, a real trap. Therefore our analysis proposes another perspective, the relevance of the model for IS design in the context of business engineering, and is builded as a systematic argumentation to clarify the relevance and the position of model and systems in the today's era of information systems for business.

Comment on the Cardozo conference on graphic and visual representations of evidence and inference in legal settings

The paper I presented at the conference gave graphical form to certain kinds of legal arguments: arguments from precedent cases (Loui, 2007). I did not intend to impose a kind of discipline on those who make such arguments. My research aims at elucidating the various forms of reasoning, proposing rules that capture their patterns and regularities, even if those rules and patterns might seem naive to experts at arguing from precedent. To a formalist, a few good rules are better than no rules, especially since artificial intelligence (AI) depends on having rules for computers to follow. A graphical way of diagramming such arguments is simply an alternative way to present the disciplined arguments and to make them comprehensible to humans, especially when the symbols are being manipulated by automata. For some of my logic colleagues, however, the implicit value of such a graphical mechanism is normative: one presumes to improve the quality of legal arguments by imposing a canonical form. This is the presumption that ran badly afoul at this conference. Why should someone who is already very good at making arguments be interested in following our rules for diagramming their arguments? My idea was simply to improve on the ubiquitous ‘Toulmin form’ for diagramming defeasible arguments (Hitchcock and Verheij, 2006). Analogies are a specific kind of argument requiring a specific kind of Toulmin structure. My theory is itself a putative improvement on existing theories of analogy from precedent. Hence, by claiming to have an improved theory of analogical argument, and claiming to refine Toulmin diagrams with that theory, it is easy to imagine that people could be led to better arguments, better rationality and better decision making, by using new diagramming conventions. This is what many formalists and many research computer scientists engaged in logic and visualization would have claimed. But why should it be true? Why are more diagramming rules better than fewer? I did not explicitly claim that people who use our diagrams make better arguments. I would not even have claimed that people who use Toulmin diagrams make better arguments with those diagrams. My paper was actually a ‘Modest Proposal for Annotating the Dialectical State’ and literary tradition required that such a paper be ironic or satirical, even humorous in the face of serious circumstances (Swift, 1996). So I suggested, whimsically, that the boxes and arrows and recursive structure of argument graphs could be replaced by a single historical image: the face of a political candidate, or a civil war general, perhaps even a football quarterback. Throw out all the rigid logical form, I wrote tongue-in-cheek, and use Barack Obama’s face for a new and untested argument of great popular force, or George W. Bush’s face for an old argument that has gotten progressively more difficult to make and which began on dubious grounds anyway. It was not such a bad idea: replace the Microsoft Windows style summaries that use plus and minus signs (or red and green lights) with a richer set of ‘emoticons.’ Some arguments get a plus sign, or a green light, when many

Optimality Model of Unsupervised Spike-Timing-Dependent Plasticity: Synaptic Memory and Weight Distribution

We studied the hypothesis that synaptic dynamics is controlled by three basic principles: (1) synapses adapt their weights so that neurons can effectively transmit information, (2) homeostatic processes stabilize the mean firing rate of the postsynaptic neuron, and (3) weak synapses adapt more slowly than strong ones, while maintenance of strong synapses is costly. Our results show that a synaptic update rule derived from these principles shares features, with spike-timing-dependent plasticity, is sensitive to correlations in the input and is useful for synaptic memory. Moreover, input selectivity (sharply tuned receptive fields) of postsynaptic neurons develops only if stimuli with strong features are presented. Sharply tuned neurons can coexist with unselective ones, and the distribution of synaptic weights can be unimodal or bimodal. The formulation of synaptic dynamics through an optimality criterion provides a simple graphical argument for the stability of synapses, necessary for synaptic memory.

Inhomogeneous birth-death and birth–death–immigration processes and the logarithmic series distribution. Part 2

A simple graphical argument described in a previous paper is used to show that the zero-modified geometric form of the population-size distribution of a time-inhomogeneous birth-and-death model is maintained when the death rates of individuals depend on their ages and times of birth. An explicit form for the population-size distribution is found. Certain models incorporating immigration, but again with general lifetime distributions, continue to lead to Fisher's logarithmic series distribution for the abundance of families of a particular size. It is shown that the zero-modified geometric form no longer holds if the model is extended to incorporate age-dependent birth rates.

A geometric approach to free variable loop equations in discretized theories of 2D gravity

We present a self-contained analysis of theories of discrete 2D gravity coupled to matter, using geometric methods to derive equations for generating functions in terms of free (noncommuting) variables. For the class of discrete gravity theories which correspond to matrix models, our method is a generalization of the technique of Schwinger-Dyson equations and is closely related to recent work describing the master field in terms of noncommuting variables; the important differences are that we derive a single equation for the generating function using purely graphical arguments, and that the approach is applicable to a broader class of theories than those described by matrix models. Several example applications are given here, including theories of gravity coupled to a single Ising spin (c = 1 2 ) , multiple Ising spins (c = 1 2 k) , a general class of two-matrix models which includes the Ising theory and its dual, the three-state Potts model, and a dually weighted graph model which does not admit a simple description in terms of matrix models.

A Renormalization Group Flow Approach to Decoupling and Irrelevant Operators

Using Wilson-Polchinski renormalization group equations, we give a simple new proof of decoupling in a φ 4-type scalar field theory involving two real scalar fields (one in heavy with mass M and the other light). Then, to all orders in perturbation theory, it is shown that effects of virtual heavy particles up to the order 1/ M 2 N 0 can be systematically incorporated into light-particle theory via effective local vertices of canonical dimension at most 4 + 2 N 0. The couplings for vertices of dimension 4 + 2 N are of order 1/ M 2 N and are systematically calculable. All this is achieved through intuitive dimensional arguments without resorting to complicated graphical arguments or convergence theorems.

Inhomogeneous birth-death and birth-death-immigration processes and the logarithmic series distribution

The modified geometric distribution for the population size of a time-inhomogeneous linear birth-and-death model is obtained by a simple graphical argument. A time-inhomogeneous birth-death-immigration process with a particular relationship between birth and immigration rates is shown to lead to Fisher's logarithmic series distribution for the abundance of families of a particular size (and hence to, for example, Ewens' formula for the allelic distribution of a population).

Argument comprehension and retrieval for editorial text

OpEd is a prototype editorial comprehension and question-answering system in the domain of politico-economic protection. Editorial comprehension in OpEd involves the application of: domain-specific knowledge, abstract knowledge of argumentation, and strategies for mapping input editorial text into conceptual structures. OpEd's model of domain-specific knowledge includes four major elements: authority triangles and social acts, to represent explicitly all the information associated with conflicts in international trade, including beliefs, goals, and conflict-resolution methods: goals and plans, to represent political and economic actions in terms of desired economic states; a trade graph, to represent causal relationships among the economic quantities associated with products and consumers; and reasoning scripts, to represent common chains of cause-effect relationships in editorials. OpEd's central, organizing constructs of argument knowledge are termed argument units (AUs). AUs consist of configurations of support and attack relationships among beliefs, where the content of each belief refers to goal/plan situations. The knowledge of argumentation encoded by AUs is highly abstract and independent of any particular domain. As a result, argument comprehension in OpEd requires instantiating AUs with the aid of politico-economic knowledge. Associated with each knowledge construct in OpEd are one or more processing strategies. These strategies are invoked to recognize knowledge constructs that are not explicitly stated in the text, but which must be inferred to understand the argument, planning and causal structure of the text. The result of processing strategies is the construction of an argument graph, organized in terms of beliefs, belief relationships, and AUs. Question answering in OpEd requires retrieving appropriate beliefs, belief relationships, or AUs from the editorial's argument graph. Intial entry to the argument graph is provided by indexing structures associated with argument participants, plans and goals. To answer belief-related questions, OpEd analyses the contents of each question into one of six conceptual question categories. Each conceptual question category leads to the selection of a specific search and retrieval strategy.

Graphical Argument Analysis: A New Approach to Understanding Arguments, Applied to a Debate about the Window of Vulnerability

Arguments and debates about politics are activities central to a democracy. Understanding arguments according to common frames of reference is not a straightforward task but demands much critical intelligence and skill. To aid in evaluating and criticizing arguments, we present in this paper a quasi-formal analytical methodology that uses a graphical scheme synthesized from the work of Toulmin and others. Arguments are analyzed into sets of propositions structurally linked by support, attack, and “warranting” relations. This method had advantages over others, since it is well-adapted to informal reasoning and since it helps identify implicit principles of argumentation (warrants), unsupported claims, circularities in reasoning, lines of possible attack, and structural relations between sub-arguments. Anyone can use the graphical template of argument elements and relations as a guide in analyzing political (or other) arguments for a variety of critical purposes. In this paper, we apply the method to a debate about the strategic window of vulnerability, a debate chosen for its continuing political relevance and the richness of its argument structure. We present graphs and their verbal interpretations, and we hope to encourage others to use this method in their own critical research.

Optimal Commodity Taxation and Tax Reform under Unemployment

This paper derives the optimal commodity tax formula and the tax reform rule which should be used in a situation of (orthodox Keynesian) unemployment. The setting considered is a four-good one-individual model with fixed real wage implying an excess supply of labor. The presentation is very simple and based on intuitive and graphical arguments. The emphasis is on comparing our results with the more traditional results derived under full employment.

Fractal lattices and universality.

The Ising problem is studied on the generalized Koch curve. By the use of graphical methods the model is solved exactly for all dimensions less than 1.44 with the result that there exists no phase transition and the critical phenomena are one-dimensional in character. Between 1.44 and 2 dimensions, graphical arguments are presented which indicate a lower critical dimensionality of 2. This work is then compared with the work of previous authors, and questions pertaining to universality are raised.

The Fourier Flexible Form

One perspective on the recent work in flexible functional forms is that the use of such forms represents an attempt to remove the modelinduced augmenting hypothesis that is inevitably linked to parametric statistical inference. The Fourier flexible form is discussed from this perspective. The discussion relies on heuristic and graphical arguments rather than formal mathematics. The generality of parametric statistical inference is limited by the augmenting hypothesis induced by model specification. For instance, to conclude that rejection of the integrability conditions in a translog consumer demand system implies rejection of the theory of consumer demand requires the augmenting hypothesis that all possible consumer demand systems must belong to the translog family (Christensen, Jorgenson, and Lau). This reliance on an assumed parametric model is not only philosophically distasteful but is of practical importance in applications. Estimators can be seriously biased by specification error; a test can reject a null hypothesis with a probability that greatly exceeds its nominal rejection probability (Gallant 1981). One way to interpret the recent work in flexible functional forms is to see it as the use of richer parametric families of models in an attempt to reduce these two sorts of statistical biases--estimator bias and excess rejection probability. Most of the flexible forms that have appeared in the literature are second-order (or Diewert-flexible) forms. Technically, this means that if g(x) is to be approximated by g(xIO), then at any given point xo there is a corresponding choice of parameters 01 such that

Application of nonperturbative quantum field theoretic methods to hadron-nucleus collisions: Background theory

An exposition of the background theory necessary for understanding the application of nonperturbative QFT methods (LSZ reduction formalism) to hadron-nucleus collisions, for example the derivation of pi-nucleus ( πn) Low and Chew Low equations, is given. The many channels and complex targets on the one hand, and the quantized field interactions on the other, introduce subtleties not well covered in particle theory or potential scattering literature. By specializing the πn Low Equation we derive a “pi-nucleon Low equation in the nuclear medium.” The second main goal of the paper is to compare this equation with Dover and Lemmer's analogous equation arrived at by graphical arguments. This requires especially making explicit the analyticity properties left tacit in their work. In is concluded that the two are essentially different.

Stability of nonlinear oscillations predicted by harmonic-linearisation technique

An analytic method of establishing the stability of oscillations which occur under both forced and limit-cycle conditions in nonlinear systems of any order is presented. The method allows the rate at which oscillations diverge or converge to be calculated. it is shown that the normally used graphical argument for assessing the stability of limit cycles is an approximate solution of the theory, obtained by neglecting the frequency and damping dependence of the nonlinearity. The theory is also used to derive a general stability bound on forced oscillations occurring in nonlinear systems. Application of the theory to a relay system stabilised by integral control indicates that stability is always predicted correctly and that divergence of stable oscillations is calculated with sensible accuracy. The jump phenomenon in a ferroresonant circuit is also examined, and a formula is derived for the stability boundaries. Digital-computer modelling is used to verify the predicted exponential change in sinusoidal output for step changes in input amplitude and frequency.