Modal Terms Research Articles

The logic of Quinean revisability

W.V. Quine is committed to the claim that all beliefs are rationally revisable; Jerrold Katz has argued that this commitment is unstable on grounds of self-application. The subsequent discussion of this issue has largely proceeded in terms of the logic of belief revision, but there is also an issue here for the treatment of Quine’s views in a doxastic modal system. In this paper I explore the treatment of Quinean epistemology in modal terms. I argue that a set of formal revisability desiderata can be distilled from Quine’s epistemic writings, and that there are demonstrably coherent and non-trivial systems that meet these conditions.

Topology Optimization of Plane Structures using Modal Strain Energy for Fundamental Frequency Maximization

This paper describes a topology optimization technique which can maximize the fundamental frequency of the structures. The fundamental frequency maximization is achieved by means of the minimization of modal strain energy as an inverse problem so that the strain energy based resizing algorithm is directly used in this study. The strain energy to be minimized is therefore employed as the objective function and the initial volume of structures is used as the constraint function. Multi-frequency problem is considered by the introduction of the weight which is used to combine several target modal strain energy terms into one scalar objective function. Several numerical examples are presented to investigate the performance of the proposed topology optimization technique. From numerical tests, it is found to be that the proposed optimization technique is extremely effective to maximize the fundamental frequency of structure and can successfully consider the multi-frequency problems in the topology optimization process.

Modified decision processes marked by linguistic forms in a problem solving task

The aim of this paper is to formalize, from linguistic markers, the on-line modifications of decision processes in terms of detachments from the spatio-temporal situation. For that, a 10-year-old’s verbal protocol, obtained during four successive trials on the Tower of Hanoi puzzle, is analyzed in the line of current cognitive linguistics, notably Culioli’s theory of enunciative operations. A first modification is inherent to decision process themselves according to their status, defining a distribution of representations between internal vs external problem spaces. That is marked by the presence or not of aggregates and of “starting terms”. A second kind of modifications is marked by modal terms. The formalization relies on a cognitive interpretation of enunciative operations involved in these detachments and suggests a new approach of information processing. Results show a progressive identification of constraints, and the reconstruction of the spatio-temporal situation at detached levels. Several kinds of partial articulations and compositions intervene in the on-line construction of elementary classes and between declarative and procedural aggregates.

LabVIEW toolkits for output-only modal identification and long-term dynamic structural monitoring

This paper describes the development of computational tools for modal identification and long term dynamic monitoring in LabVIEW environment. These tools mainly consist of two individual toolkits for structural modal identification (SMI) and continuous monitoring (CSMI), respectively. The SMI toolkit implements the frequency domain Peak-Picking (PP) and Enhanced Frequency Domain Decomposition (EFDD) method, as well as the time domain Stochastic Subspace Identification (SSI) techniques. Based on this toolkit, the user can easily develop the whole process of structural modal identification by simply pushing buttons. The CSMI toolkit was conceived for continuous dynamic monitoring excluding manual interaction. It automatically searches the latest output measurements, detects maximum vibration amplitudes and makes statistical treatment of acceleration time series, generates waterfall plots for depicting the frequency component distribution and identifies modal parameters based on automated EFDD technique. The application of these tools is briefly described based on experimental data collected at Pinhão bridge and Coimbra footbridge.

Derrida and Lacan: An Impossible Friendship?

This article explores the relation between the work of Lacan and Derrida, focusing on the use of modal logic in both writers (the categories of necessity, impossibility, contingency, and possibility). The author explores the structure of the aporia in Derrida as a peculiar conjunction of necessity and impossibility, distinct from previous forms of contradiction (antinomies in Kant and dialectical contradiction in Hegel) and therefore historically situated in relation to the tradition of metaphysics. He argues that the other two modal categories, possibility and contingency, are largely absorbed by the aporia of necessity and impossibility. In Lacan, by contrast, modal categories are introduced in Encore, his notorious seminar on sexual difference, to develop the distinction between masculinity and femininity. The author argues that the sexuation graph of Encore, which is written in symbolic logic, is later redescribed by Lacan in modal terms, and this later description alters Lacan's initial presentation, allowing for greater flexibility among these categories. The essay shows that Lacan eventually presents a model of discursive transformation in which each modal category is capable of being shifted into another. This produces a model of discursive transformation that brings Lacan closer to Foucault than most commentators have acknowledged. The broader horizon of the argument concerns psychoanalysis and historical change, and the author argues that Foucault, Lacan, and Derrida all address the problem of history and that the relations among these thinkers deserve more attention than their polemical reception has allowed, particularly with regard to attacks on psychoanalysis as ahistorical.

347 音響放射パワーの振動モード展開

The vibration modal expansion of acoustical intensity on a plane is derived as well as the expansion of structural intensity on a plate. The expansion is expressed by the superposition of modal terms composed of weight functions and cross-modal functions. The weight functions are determined by the natural frequencies and modes and the information. The cross-modal function is evaluated by the products of two modes and the information of the observed points. This paper also discusses the the relation between the structural intensity and the acoustical intensity. As a result, the relation can be found in case of the non-vortex typed structural intensity on the near vibrating plate with high damping.

2710 加振位置の選択による振動インテンシティ分布の設計(J20-3 流体関連の騒音と振動(3) 流れの制御と騒音,ジョイントセッション,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

Structural intensity presents the energy flow on structures. This paper discusses a structural intensity design method with selection of excitation position with a modal expansion of structural intensity which is expressed by superposition of modal terms expressed by the product of weight coefficients and "cross-modal functions" as a modal expansion of displacement Weight coefficient is presented by the material properties, excitation condition, and two modes with or without spatial derivatives at excitation point. Cross-modal function is presented by the product of two modes with or without spatial derivatives. Weight coefficients change by a excitation position movement but cross-modal functions not. In this paper, numerical simulation on of bending vibration on plates carried out to show the method which emphasizes a weight coefficient with movement of excitation position.

Peirce's Modal Shift: From Set Theory to Pragmaticism

For many years, Charles Peirce maintained that all senses of the modal terms "possible" and "necessary" can be defined in terms of "states of information." But in 1896, he was motivated by his work in set theory to criticize that account of modality, and in 1905 he characterized that criticism as a return "to the Aristotelian doctrine of a real possibility ... the great step that was needed to render pragmaticism an intelligible doctrine." But since Peirce was a realist about modality before 1896, and since he continued defining "possibility" in terms of "states of information" after that date, it is not clear exactly what he changed his mind about. In this essay I explain what it was that Peirce changed his mind about and why, in retrospect, he viewed that change as a decisive step in the development of pragmaticism.

A Non-modal Conception of Secondary Properties

There seems to be a distinction between primary and secondary properties; some philosophers defend the view that properties like colours and values are secondary, while others criticize it. The distinction is usually introduced in terms of essence; roughly, secondary properties essentially involve mental states, while primary properties do not. In part because this does not seem very illuminating, philosophers have produced different reductive analyses in modal terms, metaphysic or epistemic. Here I will argue, firstly, that some well-known examples fail, and also that there are deep reasons why such approaches should do so. Secondly, I will argue that it is acceptable to remain satisfied with the non-reductive account in terms of essence. To that end, I will indicate how such an explication could be put to use to support the claim that properties like colours and values are secondary. In a series of recent writings, Kit Fine has argued that essence cannot be reductively analysed in modal terms. Fine offers some examples to motivate his claim. I suggest that the primary/secondary distinction constitutes a philosophically interesting illustration.

An electromagnetic horizontal impact device for centrifuge testing

The device presented herein consists of an electromagnetic horizontal impact device. The use of a steel ball serves to avoid friction of the impact mass within the guide tube, and the presence of a slight back-slope easily leads the ball back to its initial position after bouncing on the target structure. Repeated impacts can then be triggered and tuned while in-flight. The obtained impact force duration is shorter than the impact of a truck on bridge piles; however, the required level of momentum transmitted to the pile could be attained, as could the other requirements such as remote control, reproducibility and tunability. This device produces sharp impacts that enable modeling the free vibration response of structures or the impulse response in modal terms. Two applications are presented here in order to demonstrate both the versatility of the device and the types of observations it yields: a study of the inertial pile response; and a study of structure-soil-structure interactions, as part of an effort to describe the “site-city interaction”.

0128 振動インテンシティのモード展開(J18-2 機械と環境の騒音評価,低減技術(2),J18 機械と環境の振動・騒音評価,低減技術の新展開)

This paper derives the modal descriptions of structural intensity for flexural vibration on plates. The modal expansion of the intensity is superposistioned by modal terms expressed by the product of weight function and the product of two modes with or without spatial derivative, which is called "cross-modal function" in this paper. It is also demonstrated that the expansion can design the excitation position for realizing the vortex energy flow on the plate, which flow type affects the radiation efficiency strongly. It is also shown that the products of two natural modes have the relation with the cross-mode functions, which enables to predict roughly the cross-mode functions when it is difficult to evaluate the spatial derivatives of natural mode.

Does possible world semantics turn all propositions into necessary ones?

A number of philosophical and semantic analyses make essential use of the concept of a possible world. Following tradition, we will refer to this family of analyses as “possible world semantics” (PWS). The present work argues that there is no interpretation of the term “world” that validates even a single one of the doctrines composing PWS. It is argued that, depending on what the word “world” is taken to mean, PWS entails either that all modal terms (words like “necessarily” and “possibly”) are infinitely ambiguous or that all true propositions are necessarily true. It is also argued that David Lewis’ PWS-based analysis of counterfactuals can succeed only relative to decidedly retrograde conceptions of space and time. Most importantly, it is shown that PWS is false even if it finds a way to neutralize the arguments just described. Given certain truisms about spatiotemporal existence, it is a substantive modal question whether the worlds needed to validate PWS are even possible. (As we will see, there is reason to believe that many of those worlds are in the same category as worlds that comprise light but not electromagnetic radiation.) The modal status of these worlds cannot be non-circularly resolved within a PWS-framework, and must be therefore resolved within some other modal framework, showing that PWS is parasitic on some more fundamental understanding of modality.

RESONANCE AND THE LATE COEFFICIENTS IN THE SCATTERED FIELD OF A DIELECTRIC CIRCULAR CYLINDER

The classical modal expansion for the scattered field of a plane wave from a circular dielectric cylinder is studied. A new uniform asymptotic approximation is presented for the late coefficients in this expansion, in the case of a fixed relative dielectric constant εr, both real and complex. These new approximations for the mode values are not based on the scattering matrix but rather the classical WKBJ approximations for the Bessel functions, and are valid for the entire region exterior to the cylinder, including the transition region. Furthermore, a precise asymptotic form for the location of a certain critical Regge pole is obtained. It is shown that this pole can lead to at least one dramatic resonant modal term at certain critical values, and the exponential nature of the mode in question is determined explicitly. This is followed by an extension to complex values of εrwith new uniform asymptotic approximations for the modes also being obtained, and these in turn demonstrate a heavy damping of the resonant mode.

The modality principle and work-relativity of modality

Davies argues that the ontology of artworks as performances offers a principled way of explaining work-relativity of modality. Object oriented contextualist ontologies of art (Levinson) cannot adequately address the problem of work-relativity of modal properties because they understand looseness in what counts as the same context as a view that slight differences in the work-constitutive features of provenance are work-relative. I argue that it is more in the spirit of contextualism to understand looseness as context-dependent. This points to the general problem—the context of appreciation is not robust enough to ground modal intuitions about objective entities. In general, when epistemology dictates ontology there is always a threat of anti-realism, scepticism and relativism. Davies also appeals to the modality principle—an entity’s essential properties are all and only its constitutive properties. Davies understands essentiality in a traditional way: a property P is an essential property of an object o iff o could not exist and lack P. Kit Fine has recently made a convincing case for the view that the notion of essence is not to be understood in modal terms. I explore some of the implications of this view for Davies’ modal argument for the performance theory.

THE ESSENTIAL AND THE ACCIDENTAL

AbstractThe distinction between the essential and the accidental is nearly always understood in modal terms. After criticizing some recent writings by Kit Fine that question that understanding, I develop a theory according to which whether a given feature of a thing is essential turns on whether it is explained by other features of that thing. The theory differs from the modal view by leaving room for features that are accidental even though their bearers cannot exist without them. The theory has the additional advantage of being open to the results of scientific theory.

Agnosticism About Other Worlds: A New Antirealist Programme in Modality

The modal antirealist, as presented here, aims to secure at least some of the benefits associated with talking in genuine modal realist terms while avoiding commitment to a plurality of Lewisian (or ersatz) worlds. The antirealist stance of agnosticism about other worlds combines acceptance of Lewis's account of what world‐talk means with refusal to assert, or believe in, the existence of other worlds. Agnosticism about other worlds does not entail a comprehensive agnosticism about modality, but where such agnosticism about modality is enforced, the aim of the agnostic programme is to show that it is not detrimental to our modal practices. The agnostic programme consists in an attempt to demonstrate the rational dispensability of that disputed class of modal beliefs which the agnostic eschews, but which are held by the realist and the folk. Here I attempt to motivate, describe, and illustrate such an agnostic antirealist programme in modal philosophy.

A method for stochastic seismic response analysis of non-classically damped structures

A method to calculate the stationary random response of a non-classically damped structure is proposed that features clearly-defined physical meaning and simple expression. The method is developed in the frequency domain. The expression of the proposed method consists of three terms, i.e., modal velocity response, modal displacement response, and coupled (between modal velocity and modal displacement response). Numerical results from the parametric study and three example structures reveal that the modal velocity response term and the coupled term are important to structural response estimates only for a dynamic system with a tuned mass damper. In typical cases, the modal displacement term can provide response estimates with satisfactory accuracy by itself, so that the modal velocity term and coupled term may be ignored without loss of accuracy. This is used to simplify the response computation of non-classically damped structures. For the white noise excitation, three modal correlation coefficients in closed form are derived. To consider the modal velocity response term and the coupled term, a simplified approximation based on white noise excitation is developed for the case when the modal velocity response is important to the structural responses. Numerical results show that the approximate expression based on white noise excitation can provide structural responses with satisfactory accuracy.

The Achilles’ heel of positivism

The 20th century encompasses philosophical trends as wide apart as (neo-) positivism and postmodernism. The assumed objectivity and neutrality of the former and the radical relativity claimed by the latter both have difficulties in accounting for the nature of universality. Since sense experience is directed towards concrete entities and events, the universal scope of law-statements remains problematic – particularly exemplified in the universal scope of modal terms (what will be designated as modal universality). Not even postmodernism can side-step this fundamental ontic dimension of reality. Insofar as the positivistic ideal of an objective and neutral science still dominates the thought-world of many practising (natural and social) scientists, a critique of the Achilles’ heel of positivism may render a service to the ideal of Christian scholarship, since it is argued that such a critique highlights the inevitability of a distinct theoretical view of reality which ultimately emanates from a person’s deepest convictions. The contributions of Popper and Stegmüller are contextualized in the argumentation. Popper realized that rationality needs a more-than-rational foundation and Stegmüller acknowledges that one cannot justify something without a prior trust. The inability of sense experience to account for the functional properties of natural things and their accompanying concepts indeed reveals the Achilles’ heel of positivism. This view is explained with reference to the uniqueness of function concepts employed in the historical development of the concept of matter. In the final part of the article Popper’s idea of falsification is assessed by taking into account the criticism raised by Stegmüller. In the course of the argumentation the relevance for the South African context is mentioned with reference to the idea of neutrality as it is advanced in the current debate about the teaching of religion at school.

A simple maximality principle

AbstractIn this paper, following an idea of Christophe Chalons, I propose a new kind of forcing axiom, the Maximality Principle, which asserts that any sentence φ holding in some forcing extension Vℙ and all subsequent extensions Vℙ*ℚ holds already in V. It follows, in fact, that such sentences must also hold in all forcing extensions of V. In modal terms, therefore, the Maximality Principle is expressed by the scheme (◊ □ φ) ⇒ □ φ, and is equivalent to the modal theory S5. In this article, I prove that the Maximality Principle is relatively consistent with ZFC. A boldface version of the Maximality Principle, obtained by allowing real parameters to appear in φ, is equiconsistent with the scheme asserting that Vδ ≺ V for an inaccessible cardinal δ, which in turn is equiconsistent with the scheme asserting that ORD is Mahlo. The strongest principle along these lines is □ , which asserts that holds in V and all forcing extensions. From this, it follows that 0# exists, that x# exists for every set x, that projective truth is invariant by forcing, that Woodin cardinals are consistent and much more. Many open questions remain.

Effects of Boundary Flexibility on the Vibration of a Continuum With a Moving Oscillator

In this paper, the problem of an oscillator traversing an elastically supported continuum is studied. The flexibility in the boundaries of the continuum is modeled by linear, transverse springs. The response of the continuum and the dynamic interaction force between the moving oscillator and the continuum are evaluated by an eigenfunction expansion series. To circumvent convergence difficulties associated with the jump in the shear force due to the moving interaction force, an improved series expansion employing the static Green’s function is derived. The coupled governing equations of motion are solved numerically and results are obtained to examine the effects of the boundary flexibility on the response, the dynamic interaction force, the shear force spatial and temporal distributions, as well as the convergence properties of the expansion series. It is found that high order modal terms contribute significantly to the shear force expansion series in the elastically supported model. The presence of large amplitude and high frequency components in the shear force is critical in understanding the cumulative fatigue failure of the structure. A useful and compact formula estimating the value of the support stiffness above which a boundary may be modeled as simply supported is also derived.