A Simulation Model Articulation of the REA Ontology

This paper demonstrates how the REA enterprise ontology can be used to construct simulation models for business processes, value chains and collaboration spaces in supply chains. These models support various high-level and operational management simulation applications, e.g. the analysis of enterprise sustainability and day-to-day planning. First, the basic constructs of the REA ontology and the ExSpect modelling language for simulation are introduced. Second, collaboration space, value chain and business process models and their conceptual dependencies are shown, using the ExSpect language. Third, an exhibit demonstrates the use of value chain models in predicting the financial performance of an enterprise

Performance Analysis of Dataflow Architectures Using Timed Coloured Petri Nets

We present an approach to model dataflow architectures at a high level of abstraction using timed coloured Petri nets. We specifically examine the value of Petri nets for evaluating the performance of such architectures. For this purpose we assess the value of Petri nets both as a modelling technique for dataflow architectures and as an analysis tool that yields valuable performance data for such architectures through the execution of Petri net models. Because our aim is to use the models for performance analysis, we focus on representing the timing and communication behaviour of the architecture rather than the functionality. A modular approach is used to model architectures. We identify five basic hardware building blocks from which Petri net models of dataflow architectures can be constructed. In defining the building blocks we will identify strengths and weaknesses of Petri nets for modelling dataflow architectures. A technique called folding is applied to build generic models of dataflow architectures. A timed coloured Petri net model of the Prophid dataflow architecture, which is being developed at Philips Research Laboratories, is presented. This model has been designed in the tool ExSpect. The performance of the Prophid architecture has been analysed by simulation with this model

Modelling reconfigurable manufacturing systems with coloured timed Petri nets

International audienceReconfigurable manufacturing systems (RMSs) have been acknowledged as a promising means of providing manufacturing companies with the required production capacities and capabilities. This is accomplished through reconfiguring system elements over time for a diverse set of individualized products often required in small quantities and with short delivery lead times. Recognizing the importance of dynamic modeling and visualization in decision-making support in RMSs and the limitations of current research, we propose in this work to model RMSs with Petri net (PN) techniques focusing on the process of reconfiguring system elements while considering constraints and system performance. In view of the modeling challenges, including variety handling, production variation accommodation, machine selection, and constraint satisfaction, we develop a new formalism of colored timed PNs. In conjunction with colored tokens and timing in colored and timed PNs, we also define a reconfiguration mechanism to meet modeling challenges. An application case from an electronics company producing mobile phone vibration motors is presented. Also reported are system analysis and application results, which show how the proposed formalism can be used in the reconfiguration decision making process

Cytoplasmic Prep1 Interacts with 4EHP Inhibiting Hoxb4 Translation

embryo development. Interestingly, Prep1 contains a putative binding motif for 4EHP, which may reflect a novel unknown function. development effect. mRNA to the 5′ cap structure. This is the first demonstration that a mammalian homeodomain transcription factor regulates translation, and that this function can be possibly essential for the development of female germ cells and involved in mammalian zygote development

Displacements of the central part of the Upper Silesia Coal Basin measured by GPS method

Badania sejsmologiczne silnych wstrząsów, prowadzone na terenie GZW, wskazują na ich ścisły związek z budową geologiczną tego obszaru. Występujące na tym terenie deformacje powierzchni terenu są wynikiem prowadzenia podziemnej eksploatacji górniczej. Jednak na te deformacje mogą nakładać się wpływy naprężeń tektonicznych. Potwierdzeniem tej tezy może być wykonanie długoterminowych badań geodynamicznych. Interpretacja takich badań w rejonach prowadzenia intensywnej eksploatacji górniczej jest bardzo trudna ze względu na występowanie dużych przemieszczeń, wywołanych przez szkody górnicze. Z tego powodu badania geodynamiczne prowadzone techniką GPS w rejonach górniczych powinny zostać rozszerzone dodatkowo o szczegółowe badania geologiczne oraz sejsmologiczne. W pracy przedstawiono wstępne wyniki pomiarów GPS na 8 punktach położonych południkowo w północnej i centralnej części GZW, pomiędzy Świerklańcem oraz Mikołowem.The seismological study carried out in the area of the Upper Silesia Coal Basin shows the close connection between strong tremors and geological structure. In this region tectonic stresses can be intensified by other stresses which have occurred owing to mining exploitation. To obtain the most valuable information on this relation leading to its plausible interpretation, it seems to be purposeful and advisable to apply geodynamical investigation. However, such a kind of investigation belongs to a long-term one, and its interpretation is relatively difficult owing to the fact that the area is under the intensive mining exploitation resulting in large dislocation and mining damage. That is why the geodynamical investigation in such troublesome region, despite the use of a high-tech GPS method, should be additionally developed by making detailed geological inspection and seismological research. Moreover, a geological survey should be done with great accuracy in the region of mining activity because it plays a key role in a complex interpretation based on obtained data. In the paper preliminary results of GPS measurements taken from 8 survey points are presented. The survey points were located meridionally in the north and central part of the USCB between Świerklaniec town and Mikołów town

Temperature dependences of surface magnetoelastic constants of ultrathin Fe/GaAs (001) films

The magnetoelastic constants of epitaxial iron films prepared by dc magnetron sputtering on single crystal GaAs (001) substrate in argon atmosphere and covered with a protective Si layer have been investigated in the temperature range 10–300 K by means of the strain modulated ferromagnetic resonance. It has been shown that the magnetoelastic constants strongly depend on the thickness of the film. The surface components of the magnetoelastic constants have been determined and analyzed within the Néel and dipolar models. The proposed analysis of experimental data gives chance for deeper insight into mechanisms responsible for magnetostriction of iron thin films

Магнитооптические исследования фазовой Н-Т-диаграммы многослойной пленки Fe/Si

В температурном интервале 25-300 K проведены магнитооптические исследования процесса перемагничивания многослойной пленки Fe/Si, имеющей кубическую магнитокристаллографическую анизотропию. Обнаружено, что возрастание биквадратного обменного взаимодействия с понижением температуры вызывает спонтанный фазовый переход второго рода из коллинеарного антиферромагнитного состояния в неколлинеарное. Наличие в пленке кубической анизотропии приводит к появлению спонтанного и индуцированных магнитным полем фазовых переходов первого рода между неколлинеарными состояниями. Магнитооптические исследования позволили построить магнитную фазовую Н-Т-диаграмму многослойной пленки Fe/Si при ориентации внешнего поля вдоль оси трудного намагничивания [110]. Проведен расчет фазовой H-T-диаграммы в рамках модели, учитывающей билинейный обмен и кубическую анизотропию, константы которых I1 и K предполагались не зависящими от температуры, а также биквадратный обмен с линейно зависящей от температуры константой I2. Получено удовлетворительное согласие экспериментальной и расчетной фазовых диаграмм.The magnetization reversal of a multilayered Fe/Si film having cubic magnetocrystalline anisotropy is investigated in the temperature interval 25–300 K by magnetooptical methods. It is found that the growth of the biquadratic exchange interaction as the temperature is lowered causes a spontaneous second-order phase transition from a collinear antiferromagnetic state to a noncollinear state. The presence of cubic anisotropy in the film gives rise to spontaneous and magnetic-field-induced first-order phase transitions between noncollinear states. Magnetooptical studies permit constructing the H–T magnetic phase diagram of the multilayered Fe/Si film for an orientation of the external field along the hard magnetization axis [110]. A calculation of the H–T phase diagram in the framework of a model taking into account the bilinear exchange and cubic anisotropy, with constants I1 and K that are assumed to be independent of temperature, and also the biquadratic exchange with a linearly temperature-dependent constant I2. Satisfactory agreement is obtained between the experimental and calculated phase diagrams