This paper presents a design tool of impedance controllers for robot manipulators, based on the formulation of Lyapunov functions. The proposed control approach addresses two cha\-llen\-ges: the regulation of the interaction forces, ensured by the impedance error converging to zero, while preserving a suitable path tracking despite constraints imposed by the environment. The asymptotic stability of an equilibrium point of the system, composed by full non\-li\-near robot dynamics and the impedance control, is demonstrated according to Lyapunov's direct method. The system's performance was tested through the real-time experimental implementation of an interaction task involving a two degree-of-freedom, direct-drive robot.
Philosophy of technology was not initially considered a consolidated field of inquiry. However, under the influence of sociology and pragmatist philosophy, something resembling a consensus has emerged in a field previously marked by a lack of agreement amongst its practitioners. This has given the field a greater sense of structure and yielded interesting research. However, the loss of the earlier “messy” state has resulted in a limitation of the field’s scope and methodology that precludes an encompassing view of the problematic issues inherent in the question of technology. It is argued that the heterodox disunity and diversity of earlier philosophy of technology was not a mark of theoretical immaturity but was necessitated by the field’s complex subject matter. It is further argued that philosophy of technology should return to its pluralistic role as a meta-analytical structure linking insights from different fields of research. and Filosofi e techniky nebyla zpočátku považována za ucelenou oblast bádání. Pod vlivem sociologie a pragmatické fi losofi e se však postupně začal utvářet určitý konsensus, který dal fi losofi i techniky větší strukturovanost a nová témata k výzkumů. Ztráta dřívějšího „chaotického“ stavu však vedla k omezení rozsahu a metodiky tohoto oboru a znesnadňuje komplexní pohled, který je pro zkoumání technologie nezbytný. V tomto článku budeme zastávat pozici, že heterodoxní nejednotnost a rozmanitost dřívější fi losofi e techniky nebyla známkou teoretické nezralosti, ale nutným důsledkem složitosti zkoumané oblasti. Filosofi e techniky by se dle nás měla vrátit ke své pluralitní roli metaanalytické struktury, která spojuje poznatky z různých oblastí výzkumu.
Iron is an essential limiting factor for primary production in many marine systems. The present study investigated differential regulation of protein expression in marine phytoplankton Prymnesium parvum under low Fe concentration. The phytoplankton was grown in f/2 culture medium in artificial seawater with low (0.0025 μM) and high (0.05 μM) Fe concentrations. Two-dimensional differential gel electrophoresis and matrix-assisted laser desorption-ionization-time of flight-mass spectrometer analysis were performed for protein identification and characterization. The growth of the alga declined substantially under the low Fe compared to the high Fe concentration. Under low Fe conditions, P. parvum upregulated 10 proteins including chloroplastic ATP synthase subunit b, D2 protein of PSII, D1 protein of PSII reaction centre, and light harvesting complex II protein, most of which are associated with photosynthetic activities in PSII. The results suggest that the marine alga P. parvum altered the biosynthesis of several photosynthetic proteins in order to cope with low Fe conditions., M. M. Rahman, M. A. Rahman, T. Maki, T. Nishiuchi, T. Asano, H. Hasegawa., and Obsahuje bibliografii
Let $(H,\alpha )$ be a monoidal Hom-Hopf algebra and $(A,\beta )$ a right $(H,\alpha )$-Hom-comodule algebra. We first introduce the notion of a relative Hom-Hopf module and prove that the functor $F $ from the category of relative Hom-Hopf modules to the category of right $(A, \beta )$-Hom-modules has a right adjoint. Furthermore, we prove a Maschke type theorem for the category of relative Hom-Hopf modules. In fact, we give necessary and sufficient conditions for the functor that forgets the $(H, \alpha )$-coaction to be separable. This leads to a generalized notion of integrals.
A modified exponential model was used to describe light-response curves of Nicotiana tabacum L. The accuracies of an exponential model, a nonrectangular hyperbola model, a rectangular hyperbola model, a modified rectangular hyperbola model and the modified exponential model were evaluated by Mean square error (MSE) and Mean absolute error (MAE). The tests MSE and MAE of the modified exponential model were the lowest among the five models. The light saturation point (LSP) obtained by the exponential model, the nonrectangular hyperbola model and the rectangular hyperbola model were much lower than the measured values, and the maximum net photosynthetic rates (Pmax) calculated from these models, were greater than the measured values. Pmax at LSP of 1,077 μmol m-2 s-1 calculated by the modified exponential model was 12.34 μmol(CO2) m-2 s-1, which was more accurate than the values obtained from the modified rectangular hyperbola model. The results show that the modified exponential model is superior to other models for describing light-response curves. and Z. Y. Chen ... [et al.].
In this paper a model for the recovery of human and economic activities in a region, which underwent a serious disaster, is proposed. The model treats the case that the disaster region has an industrial collaboration with a non-disaster region in the production system and, especially, depends upon each other in technological development. The economic growth model is based on the classical theory of R. M. Solow (1956), and the full model is described as a nonlinear system of ordinary differential equations.
In this paper, we present a novel quantitative description of intracellular and t-tubular Ca2+ dynamics in a model of rat cardiac ventricular myocyte. In order to simulate recently published data, the model incorporates t-tubular and peripheral dyads and intracellular subspaces, segmentation of the t-tubular luminal volume, reformulation of the inactivation properties of t-tubular land peripheral L-type calcium current (ICa) and a description of exogenous Ca2q+ buffer function in the intracellular space. The model is used to explore activity-induced changes of ion concentration in the intracellular and t-tubular spaces and their role in excitation - contraction coupling in ventricular myocytes. and Obsahuje Appendix se seznamy literatury, užitých zkratek a symbolů
In this paper we show that the measure generated by the indefinite Henstock-Kurzweil integral is $F_{\sigma \delta }$ regular. As a result, we give a shorter proof of the measure-theoretic characterization of the Henstock-Kurzweil integral.
Short-winged (brachypterous) and long-winged (macropterous) adult females of Pyrrhocoris apterus (L.) originating from a Mediterranean population (Israel) were analyzed for their adipokinetic responses. The adipokinetic response, expressed as an increase of haemolymph lipids after injection of adipokinetic hormone from Locusta migratoria (Lom-AKH-I), was assessed in relation to age and dose of the hormone. We demonstrate in this study that the adipokinetic responses induced by bug's corpora cardiaca extract and Lom-AKH-I were dose-dependent for both brachypterous and macropterous females. Significant differences between the morphs were recorded for doses >= 0.25 corpora cardiaca equivalent (P < 0.01) and doses >= 0.25 pmol Lom-AKH-I (P < 0.05). The haemolymph lipid elevations induced in both morphs by 2 pmols Lom-AKH-I are comparable with that induced by crude extract of one pair of the bug's own corpora cardiaca. The age-dependent test showed much higher adipokinetic responses (P < 0.01) in macropterous females (>= 5 days old) than in the brachypterous females of the same age, when treated with 2 pmols Lom-AKH-I. Starting from day 7, the concentration of haemolymph lipids was also considerably higher (2.5-5 times) in macropterous females than in the brachypterous ones. The obtained data indicate that difference in mobilization of lipids between brachypterous and macropterous females is a geographically independent feature and represents a true wing morph characteristic of P. apterus., Dalibor Kodrík, Radomír Socha, and Lit
People spend a large part of their awake time at work, which can have a huge impact on their life satisfaction. Scholars have found that job satisfaction influences life satisfaction, but the role of work alienation is little studied. While work alienation reportedly diminishes life satisfaction, just how job satisfaction relates with these two constructs has not yet been clarified. Currently, the role of labor union membership is an underestimated aspect of this relationship. Although the relationship between union membership and job satisfaction has been variously studied, its relationship with other variables (e.g., work alienation and life satisfaction) remains less investigated. To fill this gap, the authors examined the influence of work alienation on job and life satisfaction in relation to belonging or not to a public administration workers’ union. Self-report questionnaire responses (N=479) indicated a negative relationship between work alienation and job satisfaction and a negative influence on overall quality of life. The relationship between work alienation and life satisfaction, however, was moderated by union membership. Union memberships mitigated the negative relationship between work alienation and life satisfaction and may be considered a protective factor for workers’ quality of life. and Lidé tráví hodně svého času v práci, což může mít velký dopad na jejich životní spokojenost. Bylo zjištěno, že spokojenost s prací ovlivňuje spokojenost se životem, ale role práce byla málo zkoumána. Zatímco bylo zjištěno, že odcizení snižuje životní spokojenost, musí být ještě zkoumáno, jak spokojenost s prací souvisí s těmito dvěma konstrukty. V současné době je role členství v odborech podceňovaným aspektem tohoto vztahu. Ačkoli byl vztah mezi členstvím v odborech a spokojeností s prací zkoumán mnohokrát, vztah s jinými proměnnými (např. pracovní odcizení a spokojenost se životem) byl studován méně. Proto autoři zkoumali dopad pracovního odcizení na spokojenost s prací a životní spokojenost ve vztahu k členství v odborech pracovníků veřejné správy. Odpovědi na sebehodnotící dotazník (N = 479) naznačily negativní vztah mezi pracovním odcizením a spokojeností s prací a negativní vliv na celkovou kvalitu života. Vztah mezi pracovním odcizením a životní spokojeností byl však zmírněn členstvím v odborech. Členství v odborech zmírnilo negativní vztah mezi mezi pracovním odcizením a životní spokojeností a lze je považovat za ochranný faktor pro kvalitu života zaměstnanců.