18420 research outputs found
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Analysing and Understanding the Construction of Vernacular Buildings at the National Technical University of Athens
No full textThis paper presents a course organized by the department of Architectural Technology of the School of Architecture of the National Technical University of Athens (NTUA) that focuses on the systematic architecture survey and structural analysis of traditional settlements and buildings. The course is an “elective” study course in the 8th semester of the undergraduate studies that is run continuously with great success and feedback from students since the academic year 1975–76
Singularity Avoidance by Virtual Redundant Axis and its Application to Large Base Motion Compensation of Serial Robots
No full textThis paper describes a new method for robot hand wrist singularity avoidance by using a virtual redundant axis. The method is described for the application of large spatial robot base motion compensation for a 6 degrees of freedom serial manipulator using an inertial measurement unit such that the end effector maintains a prescribed target location. The overall system is tested for a KUKA KR500 system and computer-generated as well as real wave signals with large amplitudes
Modelling and Assessment of Multi-Agent Systems for Intelligent Safety Control in Railway Transport
No full textThe purpose is research of methods for multi-agents to control electric railway transport system. Methods of scheduling theory define criteria for target functions of the optimal control and safety task. Mathematical models and procedures are developed for control of electrical processes using multi-criteria decision making and optimization of traffic control. The model of railway transport and
signalling system is proposed and target functions for multi-criteria optimization are defined. Experiments show that developed models and methods are suitable for realtime railway control system and give possibility to prevent accidents on railway transport
Ab Initio Modeling of Sulphur Doped TiO2 Nanotubular Photocatalyst for Water-Splitting Hydrogen Generation
No full textIn order to construct an efficient visible-light-driven TiO2 photocatalyst for water splitting applications, one has to perform improvements of its electronic structure. In this theoretical study we consider single-walled anatase TiO2 nanotubes having following morphologies: (101) 3-layered wall with chirality indexes (n,0) and (n,n), (101) 6-layered wall with (n,0) and (0,n), (001) 6-layered wall with (n,0) and (0,n), and (001) 9-layered wall with (n,0) and (0,n). The latter configuration occurs to be the most energetically stable, due to possessing negative strain energy. In our study the most stable 9-layered anatase (001) (0,n) nanotube has been doped with sulphur. According to obtained results sulphur dopant creates the mid-gap states the TiO2 nanotube to be a good candidate for efficient photocatalyst working under day light irradiation
Modeling of Intelligent Agents and Neural Network Controller for Maritime Transport
No full textThe purpose of the research is to develop new mathematical models and new algorithms for intelligent agents with neural network controllers in maritime transport. Main goal of research is increasing of safety level of maritime transport. The research includes the analysis and modelling of intelligent electronics devices based on multi-agent approaches. Methodologies used in research are intelligent electronic devices and negotiations, artificial neural network controllers, bond graphing for mechatronic system analysis and control. The research proposes the solution for control task between intelligent maritime transport units and intelligent maritime control units with a purpose to prevent accidents. The model includes algorithms of intelligent ship mechatronic system control and intelligent schedule control
Development and Modelling of Scheduling Theory Algorithms for Intelligent Electric Transport System
No full textThe purpose of research is to develop new mathematical models and new algorithms for intelligent devices to control in electric transport system taking in account dynamic parameter of city transport system. Models and algorithms are proposed for multi-criteria optimization. Main goal of research is energy saving for public electric transport. Mathematical model and scheduling theory algorithm is developed and proposed in the paper to solve multi-criteria optimization task minimizing idle time and electric energy used by public electric transport and maximize average speed of the flow in traffic jam. Mathematical model of public electric transport system has a set of dynamic parameters. All these variables are changing continuously. That is why scheduling theory algorithm is necessary to adopt optimal solution to current input dynamic parameters. Scheduling theory algorithm with dynamic input parameters can be very useful to create schedule for traffic lights according to transport flows and public electric transport schedule to avoid idle time, directive term infringements and to provide faster service to passengers. Paper presents a practical example to test proposed mathematical model and workability of developed algorithm
Finding an Optimal Solution for Biowaste Management System in the Baltic States
No full textThe use of biowaste as a resource allows for the execution of the EU common objectives regarding the minimization of the deposited amount of biodegradable waste. Also, by using biowaste to convert waste to energy (biogas, waste incineration) the reuse of waste materials increases. Unfortunately, organic waste management is underdeveloped in the Baltic States. The aim of this research is to find an optimal solution for biowaste treatment for the conditions in the Baltic States. Furthermore, the assessment of different scenarios through a multi-criteria sustainability assessment will occur. This paper discusses the application of biowaste management systems for energy issues in the region by integrating ecological, socio-economic and economic aspects. This paper presents an analysis of the possibilities to utilize biowaste for energy production in the Baltic States, including biogas production from landfill gas and biogas production from biowaste by the method of anaerobic digestion and waste incineration
Holistic Human Resource Management Model towards Sustainable and Sophisticated Business
No full textThe aim of the paper is to analyse different human resource management (HRM) models and aspects of corporate social responsibility and creating shared value for building holistic model towards sophistication and sustainable development of the company. Research methods such as analysis and synthesis of the relevant scientific literature, logical and comparative analysis, as well as analytic hierarchy process (AHP) method are applied. Based on both the theoretical research and empirical analysis the authors show the factors, practices and outcomes of different models; developed holistic human resource management model; and draw conclusions regarding importance of HRM practices, the interconnectedness of human resource management and sustainability
Signālu diskretizācijas un atjaunošanas paņēmienu izpēte
No full textDarbā ir pētīti dažādi signālu diskretizācijas un atjaunošanas paņēmieni ar mērķi
izstrādāt teorētisku pamatojumu pieņēmumam, ka signālus ar laikā mainīgu spektrālo sastāvu precīzi var reprezentēt ar nolasēm, kuru izvietojumu laikā nosaka signāla aktivitāte – jo straujāk mainās signāls (jo lielāka lokālā frekvence), jo biežāk tiek ņemtas nolases, un otrādi – jo lēnāk mainās signāls (jo mazāka lokālā frekvence), jo lielāki ir laika intervāli starp secīgām nolasēm
Levoglikozenona iegūšanas iespējas, veicot koksnes priekšapstrādi un katalītisko pirolīzi
No full textIzstrādājot lapu koksnes un citas ar pentozāniem bagātas biomasas kompleksu izmantošanu, no
mikrokristāliskās celulozes, sulfātcelulozes un no lignocelulozes ar katalītisko pirolīzi, kā katalizatoru
izmantojot fosforskābi, iegūts dehidratētais 1,6 – anhidrocukurs – levoglikozenons, kuru izmanto kā analogu dabiskiem bioloģiski aktīviem savienojumiem. Ir noteikts, ka visaugstākie levoglikozenona iznākumi (vairāk nekā 30% pēc analītiskas pirolīzes datiem) ir izejvielām, kuras satur lignīnu, pateicoties tam, ka lignīns veic celulozi aizsargājošas funkcijas pirolīzes laikā