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Method for Identification the Elastic Properties of Polymer Materiāls by Using Thin-Walled Cylindrical Specimens (TWCS Method)
No full textThe method of determination of the elastic modulus is based on a solution to the problem of compression of a thin-walled circular cylindrical tube by two parallel planes. The contact problem is solved by the finite-element method (ANSYS). The deformation of a thin polymer shell is characterized by great displacements and relatively low elastic deformations in a large range of movement of parallel planes. This method was employed to calculate the elastic modulus for a series of experimental specimens consisting of five polymer compositions, whose elastic modulus have been found earlier via standard tension tests. The good correspondence between the results confirms the efficiency of the given method
Development of Energy Consumption Calculation Program for Indirect Adiabatic Cooling Equipment
No full textThis paper reports on development of energy consumption calculation program for water-side indirect adiabatic cooling equipment, operating under modes of free cooling, indirect
adiabatic cooling, indirect adiabatic cooling with mechanical cooling, and just mechanical cooling
Structure of Automated Railway Electric Vehicle Safety Control System
No full textObjective of this paper is to design a structure of a safety control system for electric vehicles’ circuits, drives and brakes. The authors review analysis methods used to detect electrical circuits, engines and brakes failures during its operation while outside the technical service environment. The authors examine the algorithms used in artificial immune systems to review possibility to apply them to the system
Epistēmiskā loģika aģentu komunikācijā un zināšanu formalizēšanā
No full textDaudzaģentu sistēma ir sistēma, kas sasitāv no vairākām daļēji autonomām komponentēm (aģentiem). Pētījumi liecina, ka, pirmkārt, šādās sistēmās katram aģentam ir nepietiekamas zināšanas un spējas visas problēmas atrisināšanai. Otrkārt, problēmas risināšanai nav centralizētas vadības. Treškārt, zināšanas un ievades dati tiek iegūti decentralizētā veidā. Ceturtkārt, spriešanas procesi bieži vien ir asinhroni. Tā kā aģenti šādās sistēmās var būt arī heterogēni, tad šie fakti liecina par to, ka nepieciešams formāls veids, kā tiem nodot savas zināšanas un spriest par citu aģentu zināšanām. Epistemoloģijas, kā zinātnes par zināšanām, ietvaros tiek pētīti ar zināšanām saistītie procesi gan individuālu, gan vairāku aģentu situācijās. Daudzaģentu gadījumā nepieciešams apskatīt tādus zināšanu veidus, kā vispārīgās, kopīgās un dalītās zināšanas. Šajā rakstā tiek apskatītas epistēmiskās loģikas pielietošanas iespējas komunikācijas un spriešanas nodrošināšanai daudzaģentu sistēmās
Актуальные проблемы реализации директив Европейского Союза в сфере страхования
No full textВиды страхования, характерные для стран с развитой рыночной экономикой, не имели возможности получить развитие в странах Балтии в период Советского союза. Граждане были вынуждены довольствоваться страхованием строений, домашнего имущества, средств транспорта и некоторых других объектов. Кроме того, предлагался определенный набор разновидностей личного страхования, проводимого на условиях, диктуемых единственным страховщиком-монополистом в лице системы органов государственного страхования. Существовавшие условия хозяйственной деятельности не благоприятствовали использованию страхового метода охраны имущества предприятий и организаций, ущерб возмещался в основном посредством использования дотаций из общегосударственных бюджетных резервов. Переход к рыночным отношениям, формирование многоукладной системы хозяйствования, основанной на разнообразных формах собственности, создало объективные предпосылки для активного внедрения в сферу экономики страхования как одного из гарантов обеспечения финансовой устойчивости хозяйствующих субъектов. Теперь они сами должны заботиться о собственном экономически устойчивом положении, сохранности материальных объектов и средств, кредито- и платежеспособности, т.к. убытки от стихийных бедствий, техногенных аварий и иных превратностей рынка должны иметь надежный и гарантированный финансовый источник покрытия
An Introduction to Mobile Agent-Supported Business Process Management
No full textBusiness Process Management Systems (BPM systems) are used to control, analyze and manage business processes in organizations. BPM systems help to reduce the amount of administrative effort and focus on the processes which add value and generate income. This paper starts with an overview of two major BPM system design approaches – centralized and agent-based. Then it describes how intelligent agents can improve the effectiveness of business processes in an organization. Finally it covers modern BPM in the cloud concepts and associated issues, and provides an outlook on how these can be addressed by using mobile agents
Wiki Approach and Student Engagement in the Learning Process
No full textWikis are one of Web 2.0 tools that can be used in the e-learning process. This article investigates how to engage students to use wiki environment. The study is based on cognitive learning theory and engagement theory. This article evaluates how learner's activity in wiki depends on interaction with teacher. Direct observation, subject teaching, literature and wiki statistical data are used to analyse student activity in a wiki environment. The results of the research indicate that appliance of wiki in informal adult learning is low when teacher do not facilitate learning process. Moreover, the author makes some recommendations for improving learning process in wiki environment to support education for sustainable development
Intelligent Agents for Business Process Management Systems
No full textThe chapter is focused on the usage of intelligent agents in business process modelling and business process management systems in particular. The basic notions of agent-based systems and their architectures are given. Multiagent systems as sets of multiple interacting software agents, as well as frameworks and methodologies of their development are discussed. Three kinds of architectures of agent-based systems – holons, multi-multi-agent systems and aspect-oriented architecture are described. Examples of already implemented agent-based systems in logistics, transportation and supply chain management are given. The chapter gives an insight into recent business process management systems and their architectures, and highlights several issues and challenges which underpin the necessity for agent-based business process management. Methodologies and implementation of agent-based business process management systems are discussed and directions of future research in this area are outlined
Sensing Element Performance Analyses Using In-Situ Measurements of Electric Resistance, Mass and the Sample Length Change
No full textSensing element made of polyisoprene and nanostructured carbon black particles (mean size: 30nm, specific surface: 950m2/g) for organic solvent vapour (osv) detection have been produced. To create very sensitive and reusable sensor material for the air quality monitoring, we have to analyze possible sensor material osv detection performance. Using in-situ measuring technique we determined absorbed analyte amount by the composite, analyte induced elongation of the sample and electric resistance change(see Fig. 1).
Mass-sorption data is the source for evaluation of sensor material suitability for vapour detection. First, we can calculate analyte diffusion coefficient in to the composite. Second, we can find out diffusion behaviour. From diffusion theory: , where Mt is mass uptake in time t, M∞ is mass uptake, when time (t) approaches infinity. n and k are constants. If n=0,5 then the rate of diffusion is much slower than molecular chain relaxation (Fickian diffusion). When diffusion is very rapid compared with molecular chain relaxation process, then it is called Supercase II and n≥1.The third one is non-Fickian diffusion (0,5<n<1) that occurs when the diffusion rate and molecular chain relaxation are comparable [1]. For sensor material with immediate response to vapour the value of n should be within 0,5≤n<1.
Length and electric resistance measurements let us evaluate resistance change mechanism. We have found out that at short exposure time electric resistance of the composite increases due to tunnelling current decrease in thin layers of matrix between carbon black aggregates (see Fig.2. 1.tunneling). But further exposure of composite to vapour leads to extreme increase of R/R0 and it is related to destruction of the conducting network (at deformations larger than 0,018). The process can be described by equation (see Fig.2.):
, where R is samples electric resistance, R0–samples initial electric resistance and Δl/l0–relative elongation of the sample [2]
Shape Optimization of Mounting Disk of Railway Vehicle Measurement System
No full textNowadays special tensometric wheel pairs are used for the wheel - rail system monitoring. In this work the task of unification of the tensometric wheel pairs and reducing of the expenses required for testing is considered. The equipment allowing realization of the measurements for the monitoring of wagon or locomotive system wheel–railing using ordinary standard wheel pair is elaborated. The objective of optimization is to find the shape of the equipment’s mounting disk with minimal weight constrained by specified displacement and stress levels. Dynamic excitations due to the rail irregularities and flat of wheel are taken into account. The strength calculations of the mounting disk are realized by FEM and are relatively time consuming. The conventional topological optimization as well as shape optimization using metamodels is discussed. Procedures of metamodel building by global and local approximations, as well as kriging are discussed in detail. The optimal curved shape of the cross-section of the ellipsoidal mounting disc is elaborated