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En el trabajo de Verónica Rodríguez-Blanco presentado y debatido en este número se propone el siguiente vínculo entre la teoría del derecho y la teoría de la acción: el teórico del derecho debería partir de una teoría correcta de la acción humana, a saber, una que permita captar el “sentido y propósito” (point) de las acciones de los participantes de la práctica jurídi- ca. Según la autora, la metodología hartiana del punto de vista interno es “inestable” porque no logra este objetivo. Tres son las críticas que enfrenta la autora: una que discute principalmente el alcance y objetivo de la teoría de Hart; otra que cuestiona que el punto de vista interno revista algún privilegio como metodología científica; y una tercera que discute centralmente cuál sería una teoría correcta de la acción humana. Por mi parte, teniendo en cuenta la distinción entre explicaciones normativas y causales, destaco que no toda explicación basada en reglas presupone la representación por parte del agente del propósito valioso de la práctica o institución.

En el trabajo Rastreando las críticas de Finnis al punto de vista interno de Hart: inestabilidad y el “sentido y propósito” de la acción humana en el derecho, la iusfilósofa Verónica Rodríguez-Blanco continúa el desarrollo de su concepción sobre la naturaleza y el concepto del derecho, profundizando la metodología necesaria para darle solución a esos asuntos. La mayor parte del texto que presento a continuación se dedica a recons- truir las ideas de Rodríguez-Blanco sobre estos asuntos fundamentales y articular sus ideas con la metateoría de los conceptos científicos y varios de sus problemas metodológicos centrales. Todo esto me permite además enunciar algunas críticas puntuales en contra de la posibilidad de que la metodología de Rodríguez-Blanco para identificar el concepto de Derecho brinde razones epistemológicamente relevantes para sustentar que el concepto así identificado presenta la naturaleza del Derecho.

Este trabajo reconstruye algunos aspectos centrales de la distinción de Hart entre punto de vista interno y punto de vista externo, enfatizando cuál es el sentido y propósito de la distinción en la teoría del derecho. Para esto, se contextualiza la propuesta de Hart dentro de “la revolución en la filosofía del lenguaje ordinario”, mostrando sus conexiones con los trabajos de Wittgenstein y Winch. Esta reconstrucción busca dar respuesta a la crítica según la cual el punto de vista interno hartiano es inestable y que, por lo tanto, no puede explicar el sentido de las acciones en el derecho.

En el artículo publicado en el presente volumen, Verónica Rodríguez-Blanco argumenta que el punto de vista interno hartiano es inestable en la medida que, al centrarse en los estados mentales del agente, solo puede conducirnos a comprender el sentido o propósito de las acciones de un modo accidental. El núcleo del argumento es que el punto de vista interno presupone un enfoque inward-looking de la acción y que, para comprender adecuadamente el sentido o propósito de las acciones, es necesario adoptar, en cambio, un enfoque outward-looking. En este artículo, sostengo que los argumentos de Rodríguez-Blanco en contra del enfoque inward-looking de la acción son insatisfactorios. Argumento, además, que las críticas que dirige a la teoría del punto de vista jurídico de Raz están igualmente desencaminadas, y que su propuesta positiva relativa al rol de las reglas jurídicas en el razonamiento práctico tiene serios defectos.

Finnis nos dice que el participante de la práctica jurídica, por ejemplo, el ciudadano, el juez, el abogado, están comprometidos con el derecho y están interesados en distinguir entre una norma buena y una no tan buena, entre una directiva justa y una directiva injusta, entre una decisión racional de un tribunal y una decisión irracional. El punto de vista interno de Hart se niega a hacer ulteriores distinciones entre los casos centrales y periféricos del derecho y esto trae inestabilidad al concepto. El punto de vista interno de Hart como inestable puede remontarse a una crítica más fundamental, a saber, el punto de vista interno de Hart no puede ser usado para entender el sentido y propósito de las acciones humanas y, por lo tanto, no podemos basarnos en el punto de vista interno de Hart para identificar diferencias de importancia que pueda hacer cualquier actor en el campo. En la literatura sobre la “metodología”, este argumento de la inestabilidad es pasado por alto y sus premisas no han sido cuidadosamente examinadas. En este capítulo, trataré de mostrar que la idea de que el punto de vista interno es inestable es, a la vez, clave para entender los límites de la teoría del derecho de Hart y para arrojar más luz sobre la idea de que el derecho debe concebirse en términos de un caso central o focal.

El libro Legalidad de Scott Shapiro se propone llevar a cabo una estimulante, pero ardua, tarea filosófica, a saber: ofrecer una explicación de aquello que el derecho es y de por qué vale la pena tenerlo. Su “Teoría del derecho como plan” aborda la primera cuestión en términos de la denominada tesis de los “hechos sociales” y la segunda en términos de la tesis del “fin moral”. Así, el derecho está determinado únicamente por hechos sociales, pero posee un punto moral, puesto que la finalidad de la actividad legal es solucionar algunos problemas morales. Las escuelas filosófico-jurídicas del siglo veinte se han dividido acerca de estos temas. Entre tales escuelas, Shapiro rechaza la visión realista porque deja de lado el punto de vista interno. Sin embargo, muchas afirmaciones realistas se referían al conocimiento del derecho, no a su normatividad. El artículo aborda este punto recordando también el debate entre Hart y Ross.

En este artículo se argumenta que la teoría de la planificación presentada por Scott Shapiro en su libro Legalidad ofrece una explicación mixta del fenómeno jurídico. Por una parte, pretende desentrañar la naturaleza del derecho, mediante un análisis conceptual que reconstruya fielmente el punto de vista interno. Por otra parte, Shapiro propone una explicación funcional del derecho que trasciende la pers- pectiva de los participantes. Ambas explicaciones iluminan aspectos diferentes de la práctica jurídica y, por ello, son complementarias.

Three-dimensional reorientation of a rigid body by means of several auxiliary masses moving relative to the body is considered. The algorithm presented is based on simple circular motions of the internal point masses. It is shown that the case of several masses, especially if their number exceeds three, has certain advantages compared to the case of one moving mass. The location of domains where these masses move as well as the size of these domains can be chosen according to the design requirements. The results obtained can be of interest for the control of mobile robots and other moving objects including spacecraft.

The contact interaction of two elastic semi-infinite solids with flat surfaces and different mechanical properties is studied. The solids are subjected to pressure at infinity and concentrated force is applied at internal point of the upper solid. The normal and tangential contact stresses are found assuming full stick of the solids. Based on the numerical analysis of the contact stresses, it is shown that the solids can be in stick contact or in stick-slip contact (with one or two zones of local frictional slip) depending on the magnitude and orientation of the concentrated force and elastic characteristics of the contacting materials

O objetivo deste artigo é discutir a importância da NOS (Nature of Science) na formação dos professores de ciências e no ensino de ciências em geral. Há uma centralidade acerca dessa discussão, desde que se admite que saber sobre ciência é tão importante quanto saber conteúdos de ciência. Assumimos que a NOS é um conjunto de saberes ou ?olhares? metateóricos que trata das várias características da ciência, seja do ponto de vista internalista, seja em seu caráter eminentemente cultural e social. Encontramos em Douglas Allchin e em Derek Hodson argumentos que sustentam o uso da Whole Science em detrimento do uso de listas consensuais, muito mais comuns na formação de professores e no ensino de ciências. Por fim, trazemos um exemplo de uso da Whole Science na forma de uma história ficcional, na qual vários pontos da NOS podem ser explorados para efeitos de seu ensino. This article aims to discuss the importance of NOS (Nature of Science) in the training of science teachers and science teaching in general. This is a pivotal discussion because it is assumed that knowing about science is as important as knowing the contents of science. We understand, from the outset, that NOS is a set of meta-theoretical knowledge or “views” that deal with the various characteristics of science, either from the internal point of view (its methods and its theories) or its eminently cultural and social character. After all, which NOS points are essential for teacher training? We found arguments in Allchin and Hodson that support the use of Whole Science rather than consensus lists, which are much more common in teacher education and science teaching. Finally, we present an example of Whole Science use in the form of a fictional story, in which many points of NOS can be explored in teaching. Fil: Rui Ribas Bejarano, Nelson. Universidade Federal da Bahia; Brasil Fil: Aduriz Bravo, Agustin. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Formación e Investigación en Enseñanza de las Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Santos Bonfim, Carolina. Universidade Federal da Bahia; Brasil

Internal points were introduced in the literature of topological vector spaces to characterize the finest locally convex vector topology. Very recently this concept was generalized to the one of in...

The problem of optimal spacecraft reorientation using internal point masses is considered. The masses can move inside the spacecraft arbitrarily but constrained by spatial constraints and subject to control constraints. Assuming linear and angular momentum conservation, both minimum energy and minimum time variants of the optimal control problem are considered and treated numerically. This problem is motivated by the question of whether existing momentum exchange devices provide optimal reorientation capabilities to the spacecraft and whether other potential devices could be devised and be beneficial in certain circumstances. The outcomes of numerical trajectory optimization for different spatial constraints and objectives are reported and discussed.

Inner structure appeared in the literature of topological vector spaces as a tool to characterize the extremal structure of convex sets. For instance, in recent years, inner structure has been used to provide a solution to The Faceless Problem and to characterize the finest locally convex vector topology on a real vector space. This manuscript goes one step further by settling the bases for studying the inner structure of non-convex sets. In first place, we observe that the well behaviour of the extremal structure of convex sets with respect to the inner structure does not transport to non-convex sets in the following sense: it has been already proved that if a face of a convex set intersects the inner points, then the face is the whole convex set, however, in the non-convex setting, we find an example of a non-convex set with a proper extremal subset that intersects the inner points. On the opposite, we prove that if a extremal subset of a non-necessarily convex set intersects the affine internal points, then the extremal subset coincides with the whole set. On the other hand, it was proved in the inner structure literature that isomorphisms of vector spaces and translations preserve the sets of inner points and outer points. In this manuscript, we show that in general, affine maps and convex maps do not preserve inner points. Finally, by making use of the inner structure, we find a simple proof of the fact that a convex and absorbing set is a neighborhood of 0 in the finest locally convex vector topology. In fact, we show that in a convex set with internal points, the subset of its inner points coincides with the subset of its internal points, which also coincides with its interior with respect to the finest locally convex vector topology.

In the present paper, inverse problems are considered for the impulsive Sturm–Liouville equations in the finite interval. We use formulations of the inverse problem the so called Mochizuki–Trooshin theorem and demonstrate that the coefficients of the considered problem are uniquely determined by values of the eigenfunctions in the middle of the interval and one spectrum. We also prove that some information on eigenfunctions at some internal point $$b\in \left( \frac{1}{2}, 1 \right) $$ and parts of two spectra suffice to determine all coefficients in the boundary value problem.

This paper examines the practical reality and experience of racism from the “internal point of view” of blacks who suffer racism and white racists. It uses this point of view to critically examine Carter’s and Corlett’s views regarding realism about race and racism. They suggest that theories must inquire about race and racism as categories for understanding the way-things-really-are. I argue that a plausible idea of racism, as a thick concept, must not be subservient to public policy. Rather, public policy must reflect experiential reality of racism. I argue that the views of Corlett and Carter, which tie racism to human agency, have heuristic value. However, they are too narrow; they have problematic implications, and do not sufficiently capture many putative cases and common usage of race and experience of racism.

Internal points were introduced in the literature of topological vector spaces to characterize the finest locally convex vector topology. In this manuscript we generalize the concept of internal point in real vector spaces by introducing a type of points, called inner points, that allows us to provide an intrinsic characterization of linear manifolds, which was not possible by using internal points. We also characterize infinite dimensional real vector spaces by means of the inner points of convex sets. Finally, we prove that in convex sets containing internal points, the set of inner points coincides with the one of internal points.

espanolLa teoria de la democracia deliberativa constituye una de las propuestas filosofico- politicas mas importantes de los ultimos anos para la reconstruccion normativa del Estado democratico de derecho, y que, al igual que la etica del discurso, constituye una derivacion teorica del enfoque de la racionalidad discursiva. Ahora bien, una cuestion que es necesario analizar es que tipo de relacion se plantea entre ambas teorias. Esta es una tarea pendiente, porque para algunos de los exponentes de tal teoria etica, ella parece asumir el rol de conducir y guiar de un modo exclusivo las decisiones politicas, lo cual implica una reduccion de la Filosofia politica al campo de la etica olvidando que dicha Filosofia, si bien presupone la etica, tiene sus propios principios. El presente articulo analiza entonces esta teoria politica desde un punto de vista interno, senalando los problemas que podrian seguirse a partir de abordar filosoficamente el cuestion de la politica democratica exclusivamente desde la perspectiva de la etica del discurso. EnglishThe theory of deliberative democracy is one of the most important philosophical-political proposals in the last years for the Normative reconstruction of the democratic State of Law, and, as the Discourse Ethics, constitutes a theoretical derivation of the perspective of discursive rationality. In this respect, is necessary to analyze what kind of relation there is between both theories. This one is a hanging task, because for some of its exponents the ethical theory seems to assume the role of driving and guiding, in an exclusive way, the political decisions, which implies a reduction of the political Philosophy to the field of the ethics. But, even when presupposes ethics, politics has his own rules. The present article analyzes this political theory from an internal point of view, indicating the problems that might follow from one philosophical approaching to the issue of the democratic politics exclusively from the perspective of the Discourse Ethics.

El objetivo de este artículo es ofrecer una panorámica de la evolución de la medición y gestión del riesgo financiero en los últimos 40 años, con especial mención a la banca. Tras una etapa basada en los principios de la Modern Portfolio Theory (MPT), hace 25 años se produce una revolución con la introducción del Value-at-Risk (VaR). Desde entonces, la introducción de nuevas medidas cuantitativas, con complejidad matemática creciente, no se ha detenido, en una interacción continua entre académicos, profesionales y reguladores, como respuesta a las sucesivas crisis financieras y bancarias. Entre ellas, destacan las medidas coherentes del riesgo (concretamente el Expected Shortfall), espectrales y basadas en expectiles. Se concluye que el VaR y el Expected Shortfall (ES) continúan siendo, a pesar de sus limitaciones, las dos medidas más utilizadas tanto desde el punto de vista interno de los bancos, como por parte del regulador y supervisor de su solvencia. Finalmente, se plantean algunas de las líneas de investigación en este campo que tratan de abordar los retos en el futuro de la medición del riesgo financiero en banca.

RESUMEN. Este trabajo analiza la relacion de la democracia y la argumentacion juridica desde diversas perspectivas. En primer lugar, desde un punto de vista externo, que apunta al fundamento politico y moral de las corrientes argumentativas dentro de la Filosofia del Derecho. En segundo lugar, aborda esta relacion desde un punto de vista interno, analizando el papel del principio democratico en el marco de un modelo general de racionalidad argumentativa. Y, por ultimo, pretende hacer una caracterizacion de las teorias/ideologias juridicas en el contexto de la democracia constitucional. ABSTRACT. This paper analyzes from varied perspectives the relation between democracy and legal argumentation. First, from an external point of view, that points to the political and moral foundations of the argumentative currents of Philosophy of Law. Secondly, it aproaches this relation from an internal point of view, inquiring into the rol of the democratic principle within a general model of argumentative rationlity. And, last, it pretends to characterize the various legal theories/ideologies in the context of constitucional democracy.

In this article motivated by unique representation of a topology \(\tau \) on X, we introduce some kind of representation for \(\tau \) in \({ Top}(X)\) and find the equivalent condition for a topological space to have unique representation. As the main part of the paper, we introduce the natural representation for every topology \(\tau \) on a set X of the form \(\bigwedge _{a\in L(X)}\mathscr {T}(a,\mathscr {W}_a)\), where \(\mathscr {W}_a\) is the set of all neighborhoods and deleted neighborhoods of a and L(X) is the set of all non-isolated points of X, and we characterize the spaces whose topology has unique representation. Also it is proved that every first countable Hausdorff space has unique representation property.

The article is written in response to a recent flurry of studies on international practices. In investigating this theme, International Relations scholars have drawn on diverse traditions in sociology, philosophy and organisational theory such as Bourdieu’s theory of practice, Dewey’s and James’ pragmatism, communities of practice approach and actor-network theory. One preliminary question presupposed by these investigations however is, what standpoint (if any) enables us to make sense of international practices? Our central thesis is that the proper understanding of practices – including international ones – requires the internal point of view (practice internalism). To make our case, we develop an analytic distinction between two basic standpoints: practice externalism, represented by Adler and Pouliot’s approach to international practices, and practice internalism, represented by Wittgensteinian philosopher Peter Winch. Following Winch, we argue that the practice of social science is externalist, and point to the limitations of an analysis of international practices predicated on externalist, social scientific premises.

The controlled motion of a rolling ball actuated by internal point masses that move along arbitrarily-shaped rails fixed within the ball is considered. The controlled equations of motion are solved numerically using a predictor-corrector continuation method, starting from an initial solution obtained via a direct method, to realize trajectory tracking and obstacle avoidance maneuvers., 51 pages, 59 figures, 13 tables, 2 algorithms. arXiv admin note: substantial text overlap with arXiv:1708.03829

The text contains some remarks on the methodological issues of jurisprudence. It points to important role of the so-called internal point of view in epistemology of law and it stresses an important role of the analysis of legislative language (language of the law) and legal language in an attitude of the participant of the communicational community. Tekst zawiera kilka spostrzeżeń dotyczących metodologicznej problematyki prawoznawstwa. Autorzy wskazują w nim na istotną rolę tzw. wewnętrznego punktu widzenia w epistemologii prawa oraz analiz języka prawnego i prawniczego w postawie uczestnika wspólnoty komunikacyjnej.

This paper presents a parallel mesh deformation solver using radial basis function (RBF) interpolation. The solver computes the displacement of each internal point independently without usi...

Predicting the leakage condition is of primary importance when designing metal-to-metal flanges. The gap between flange surfaces is regarded as a partially open crack with a zero stress intensity factor, then a model based on fracture mechanics is proposed for predicting leakage pressure. An analytical solution was found, with weight function, considering the condition of crack front at the most internal point of the bolt hole. Finite element and experimental tests validated the effectiveness of the model. In addition, the dependencies on the main flange dimensions were investigated and discussed, providing useful guidelines for optimal flange design.

The goal of this paper is to investigate the normal and tangential forces acting at the point of contact between a horizontal surface and a rolling ball actuated by internal point masses moving in the ball's frame of reference. The normal force and static friction are derived from the equations of motion for a rolling ball actuated by internal point masses that move inside the ball's frame of reference, and, as a special case, a rolling disk actuated by internal point masses. The masses may move along one-dimensional trajectories fixed in the ball's and disk's frame. The dynamics of a ball and disk actuated by masses moving along one-dimensional trajectories are simulated numerically and the minimum coefficients of static friction required to prevent slippage are computed., Comment: 24 pages, 28 figures, 2 tables. arXiv admin note: substantial text overlap with arXiv:1801.09178; text overlap with arXiv:1708.03829

The Primal-dual interior-point methods with a filter are one of hot issues in optimization with both equality and inequality constraints. Extensive attention has been paid and great progress has been made for a long time. Interior-point methods not only have polynomial complexity, but are also highly efficient in practice.

Two-point boundary value problem for a singularly perturbed ordinary differential equation of second order is considered in the case when the degenerate equation has three unintersecting roots from which one root is two-tuple and two roots are one-tuple. It is prooved that for sufficiently small values of the small parameter the problem has a solution with the transition from the two-tuple root of the degenerate equation to the one-tuple root in the neighbourhood of an internal point of the interval. The asymptotic expansion of this solution is constructed. It distinguishes from the known expansion in the case when all roots of the degenerate equation are one-tuple, in particular, the transitional layer is multizonal.

The controlled motion of a rolling ball actuated by internal point masses that move along arbitrarily-shaped rails fixed within the ball is considered. Application of the variational Pontryagin's minimum principle yields the ball's controlled equations of motion, a solution of which obeys the ball's uncontrolled equations of motion, satisfies prescribed initial and final conditions, and minimizes a prescribed performance index., 30 pages, 16 figures

This essay concerns Scott Shapiro's criticism that H.L.A. Hart's theory of law suffers from a “category mistake.” Although other philosophers of law have summarily dismissed Shapiro's criticism, I argue that it identifies an important requirement for an adequate theory of law. Such a theory must explain why legal officials justify their actions by reference to abstract propositional entities, instead of pointing to the existence of social practices. A virtue of Shapiro's planning theory of law is that it can explain this phenomenon. Despite these sympathies, however, I end with the suggestion that Shapiro's criticism of Hart, as it stands, is incomplete. Careful attention to Hart's notion of the internal point of view indicates that he was aware that legal justification ends with abstract objects, not practices, and that he offered his own explanation of this phenomenon.

Not only knowledge plays a central role in human life at all levels, from survival to improving the quality of life, but, since antiquity, several people have claimed that knowledge is the purpose and meaning of human life. This chapter maintains that this claim is unjustified, and that all attempts to show that human life has a purpose and meaning from an external and higher point of view are bound to be unsuccessful. Human life has indeed a purpose and meaning, but only from an internal point of view. As it has been widely held since antiquity, this purpose and meaning is happiness, which however does not consist in knowledge. On the other hand, even if happiness does not consist in knowledge, knowledge is a precondition of happiness.

Can Hart's non-cognitivism be reconciled with his rejection of the predictive and sanction-based explanations of law? This paper analyses Hart's notion of the internal point of view and focuses on the notion of acceptance of a rule along the lines of a non-cognitivist understanding of intentional actions. It is argued that a non-cognitivist analysis of acceptance of rules is incomplete and parasitic on a more basic or primary model of acceptance that does not involve mental states. This basic or primary model of acceptance explains actions in terms of other actions and in terms of reasons for actions that are both presented as good-making characteristics and transparent to the agent. If Hart's internal point of view is able to work as the key argument to reject predictive and sanction-based explanations of law, it needs to make the outward approach of intentional action basic or primary rather than rely on an inward approach such as the one advanced by non-cognitivism.

This paper discusses the problem of determining an unknown source which depends only on one variable in two-dimensional Poisson equation from one supplementary temperature measurement at an internal point. The problem is ill-posed in the sense that the solution (if it exists) does not depend continuously on the data. The regularization solution is obtained by the modified regularization method. For the regularization solution, the Holder type stability estimate between the regularization solution and the exact solution is given. Numerical results are presented to illustrate the accuracy and efficiency of this method.

We consider a linear semidefinite programming problem. To solve this problem, we propose a dual numerical method from the class of affine scaling methods. We use Ostrovskii's theorem to establish its local convergence. We also show results for test problems.

This article addresses the question of whether judges can take the internal point of view toward—accept—their legal system's rule of recognition for purely prudential reasons. It takes a fresh look at an underappreciated conceptual argument of Joseph Raz's that answers: no. In a nutshell, Raz argues that purely prudential reasons are reasons of the wrong kind for judges to accept their legal system's rule of recognition. And should Raz's argument succeed, an important necessary connection between law and morality would be established.

In this paper, inverse spectra problems for a differential pencil are studied. By using the approach similar to those in Hochstadt and Lieberman (1978) [14] and Ramm (2000) [26] , we prove that (1) if p ( x ) (or q ( x ) ) is full given on the interval [ 0 , π ] , then a set of values of eigenfunctions at the mid-point of the interval [ 0 , π ] and one spectrum suffice to determine q ( x ) (or p ( x ) ) on the interval [ 0 , π ] and all parameters in the boundary conditions; (2) if p ( x ) (or q ( x ) ) is full given on the interval [ 0 , π ] , then some information on eigenfunctions at some internal point b ∈ ( π 2 , π ) and parts of two spectra suffice to determine q ( x ) (or p ( x ) ) on the interval [ 0 , π ] and all parameters in the boundary conditions.

This paper investigates the inverse problem of determining an unknown source term in a heat equation subject to the overspecification of the solution at an internal point along with the usual initial boundary conditions, and the source term is only time-dependent. In this paper, the method of trace-type functional formulation of a problem is considered. Some numerical examples using this approach and the finite-difference method are presented and discussed.

PurposeThe purpose of this paper is to discuss the properties of transparency and excitability of positive linear time‐invariant systems under internal point delays.Design/methodology/approachThe problem is solved by combining the algebraic conditions for positivity, excitability, and transparency for the case of linear and time‐invariant dynamic systems in the presence of discrete lags.FindingsIt is shown that the excitability independent of delay is guaranteed if an auxiliary delay‐free system is excitable. Necessary and sufficient conditions for excitability and transparency are formulated in terms of the parameterization of the dynamics and control matrices, and equivalently, in terms of strict positivity of a matrix of an associate system obtained from the influence graph of the original system. Such conditions are testable through simple algebraic tests involving moderate computational effort.Practical implicationsThe practical implications mainly rely on some biological and medical problems where delays are present by nature, excitability means the activation of all the state components under positive controls after a short time in the sense that it cannot remain identically zero. In the same way, it relays on the activation of all the output components under zero controls and non‐negative initial conditions.Originality/valueThe paper extends the concepts of excitability and transparency to dynamic systems with point time‐lags which are very common in nature and some practical problems.

We consider an inverse problem for estimating an unknown time-dependent heat source H ( t ) in a heat conduction equation T t ( x , t ) = T xx ( x , t ) + H ( t ) , with the aid of an extra measurement of temperature at an internal point. The Lie-group shooting method (LGSM) was used in the solution of this inverse problem; however, when the data are acquired at an internal point we require to develop a two-stage Lie-group shooting method (TSLGSM) to solve it. This novel approach is examined through numerical examples to convince that it is a rather accurate and efficient method, whose estimation error is small even for the identification of discontinuous and oscillatory heat source under large noise.

In his book The Concept of Law, Hart advances an arresting idea: the internal point of view. The idea immediately captured the imagination of legal theorists and was envisaged as a step forward in understanding both the nature of law and its practices. There is, however, lack of clarity and ambiguity on understanding Hart’s important notion and its role in different key jurisprudential problems such as the normativity of law and the methodology of legal theory. This article reconstructs the intellectual roots of the internal point of view and argues that although the seeds of Hart’s idea can be found in Winch’s seminal book The Idea of a Social Science, there are striking differences between Hart’s and Winch’s notions of the internal point of view. Winch endeavors to explain the participant’s viewpoint in terms of what the participants are doing. On the other hand, Hart aims to provide an explanation of how the law enables judges and law-abiding citizens to determine what they ought to do. This difference has been often overlooked by legal scholars; however, it provides the key to understanding Hart’s connection between the internal viewpoint and the normativity of law, i.e., the idea that legal rules provide reasons for action and, in some circumstances, create and impose duties and obligations. The distinction also illuminates the demarcation in the methodology of legal theory between an explanation from a detached perspective, namely the second or third-person standpoint of the practical point of view and, on the other hand, either a theoretical or hermeneutical explanation of the participant’s point of view. I argue that the non-recognition of the practical/participant distinction has been pervasive in two ways. First, there has been an overemphasis on the distinction between the internal and the external point of view. Second, a more fundamental distinction between an ‘engaged’ and ‘detached’ viewpoint which is a predominant feature of the practical point of view has been under-researched.

This paper reviews and summarises the theory and techniques used when conducting hydraulic tracer tests in treatment wetlands, with particular attention paid to the practical issues to be considered during the planning and implementation phases. Typically, a single-shot impulse of tracer is introduced at the inlet and the concentration tracked at the outlet or other internal point in order to uncover information about the hydraulic characteristics of the wetland. The following aspects are discussed: the range of commonly used tracer substances, the mass of tracer to be added, and planning of the sampling regime. A range of graphical and statistical tools are described for interpreting the data from a tracer study, with example data from an impulse tracer study used to demonstrate the required computational procedures. It is recommended that a standardised approach be adopted for presenting tracer study data in order to allow the direct comparison of data from different wetland systems.

The paper critically examines Bobbio's famous disctinction between legal positivism as a method, a theory and an ideology. The author first highlights certain problems of the distinction itself and then focuses on Bobbio's self-determined position within it. Delving on Bobbio's analysis of the concepts of basic norm and rule of recognition, he demonstrates how Bobbio's later rejection of these two concepts implies acceptance of positivistic legal theory and ideology – despite the fact that he explicitly rejected them in the first place. The reason for this Bobbio's slip is found in his absorbtion in the positivist legal culture which is permeated with the internal point of view on the law. The author suggests rejecting Bobbio's tripartite disctinction of legal positivism and proposes instead to view this as a set of seldom indvisible standpoints forming a specific legal culture.