Volume 4, No. 14 (2008)
Articles
FINDING THE OPTIMAL ROUTES USING GENETIC ALGORITHMS
BALAN IONUŢ
This paper aims to describe the implementation of a genetic algorithm system in order to search the optimal routes between two cities. Above the deterministic methods, which, in most of cases, offer us the best path, the algorithm implemented here (a stochastic algorithm), can provide the best “k” paths. This option is recommended for us, if we want to choose a road from the best (short) existing. For a better exemplification we considered the map of Romania, a map with 23 cities, the route that we want to find being Arad – Suceava.
LATENT HEAT-OF-FUSION ENERGY STORAGE: EXPERIMENTS ON HEAT TRANSFER FROM CYLINDERS DURING MELTING
CĂLIMAN RADU, OLARU IONEL
Melting from an array of three staggered, electrically heated cylinders imbedded in paraffin (n-octadecane) has been studied. The shape of the melting front has been determined photographically, and the local heat transfer coefficients were measured using a shadowgraph technique. The experiments provide conclusive evidence of the important role played by natural convection on the time variation of the melt shape, the surface temperature and the instantaneous local as well as circumferentially averaged heat transfer coefficients around the imbedded heat sources. After a common solid-liquid interface is formed around the cylinders, natural convection circulation around each cylin¬der interacts strongly with the other two cylinders.
ABSTRACTION OF COMPLEX SPATIAL DATA IN OBJECT-ORIENTED ENVIRONMENT
COSTACHE GABRIEL
Geographical Information Systems (GISs) represent a powerful tool for capturing, storing, manipulating, and analyzing geographic data. This tool is being used by various geo-related professionals, such as surveyors, cartographers, photogrammetrists, civil engineers, physical planners (urban and rural), rural and urban developers, geologists, etc. They use the tool for analyzing, interpreting, and representing the real world and understanding the behavior of the spatial phenomena under their respective jurisdictions. Almost all of the systems used by the geoinformation community to date are based on two-dimensional (2D) or two-and a half-dimensional (2.5D) spatial data. In other words, one may find difficulty processing and manipulating spatial data of greater dimension than 2 in the existing systems, resulting in inaccurate or at least very incomplete information. In geomatics or geoinformatics we consider real world objects exist in three-dimensional (3D), thus it is desirable to have a system which is able to store, handle, manipulate, and analyze objects in a 3D environment.
GENETIC ALGORITHMS OPTIMIZATION USING NEURAL NETWORKS
CURCA RADU
The real life provides a large range of problems, which cannot be solved in any traditional way. An efficient approach of solving them is to use genetic algorithms. Genetic algorithms represent a search method that can be used for both solving problems and modeling evolutionary systems. Genetic algorithms are implemented as a simulation in which a population of representations of candidate solutions to a problem evolves toward better solutions. All the traditional approaches are based on evolution only, while the proposed approach will try to integrate learning in the evolutionary process.
ALGORITHM FOR COMPUTER AIDED FEATURES’ RECOGNITION
DOICIN CRISTIAN, MELNIC LUCIA VIOLETA, CONSTANTIN ILIE
The software systems developed to generate manufacturing process plans use two main methods: a variant method and a generative one [1, 3]. The modern CAPP systems are generative ones. These systems use the solid models of the parts as the input data, to which technological information, useful in planning process, is then added. Usual, the solid model is generated within a CAD system and the technological information are transferred to the module of process plans’ generation through a transfer file, having a certain format [3]. In the following sections a method for identifying the features within generative CAPP system is described. The method is based on an algorithm composed by the following steps: define the initial data, define the constraints and establish in advance the variants of process plans, establish the technical possible variants and select the optimum one and design the jigs and fixtures. The paper presents the aspects concerning the design of the module for identification of the parts’ shapes, emphasizing the algorithm for feature recognition.
A.I. APPLICATIONS: INTELLIGENT FIREWALLS
GAGNIUC MIRCEA-BOGDAN
This paper will analyze the possibility to create firewalls with AI algorithms to implement prediction methods for setting firewall rules of data traffic acceptance. Using ID3 decision tree algorithm, created by J. Ross Quinlan will be demonstrating a possible prediction possibility to implement automat decision for firewall questions. The paper will use a simple example, calculating a simple decision tree based on ID3 algorithm.
THE DETERMINATION OF THE RESIDUAL AUSTENITE QUANTITY BY THE METHOD OF PULLING OUT FROM MAGNETICAL FIELD
GHEORGHIAN MIRELA, CIUCESCU DORU
After the quenching treatment of the steels, the microstructure contains martensite (hard and brittle) and residual austenite (soft and tenacious). The quantity of residual austenite in the final structure of the quenched steels depends on many factors: the speed of heating, the chemical composition, the speed of cooling, the position of critical points Ms and Mf. There are several methods to determine the quantity of the residual austenite: the X rays diffraction, the expansion analyze, the metallographic analyze, the magnetic investigations, the ultrasonic investigations. The quantitative determination of the residual austenite based on the magnetic characteristics, may be realized by measurement of the saturated magnetization, measurement of the coercive field, measurement of the magnetic permeability etc. All these methods have as fundament the correlation between the magnetic properties and the structural constitution of the steels.
THE ENERGETIC AND EXERGIC PERFORMANCE OF GAS TURBINE COGENERATION SYSTEM
HAZI ANETA(*), HAZI GHEORGHE(*), VERNICA SORIN(*), GOGA FLORIN(**)
This paper presents a performant evaluation of gas turbine cogeneration system. For a gas turbine cogeneration system, which generates electricity and hot water, an energetic and exergetic analysis was made. Finally, energy and exergy efficiency was evaluated.
ANALYTICAL RELATION FOR DESIGN OF PROTECTIVE ZONES AT VERTICAL LIGHTNING RODS
HAZI GHEORGHE, HAZI ANETA
This paper presents some relations established by authors, for analytical design of protective zones at vertical lightning rods, according to standard NTE 001/03/00. There are presented relations for usually cases in the energetic installations: a vertical lightning rod, two lightning rods with equal heights, and two lightning rods with different heights. The analytical models proposed by authors permit easy design and verification of protective surface for complex electrical installations. For example, using these relations it can be easy design the protective surface of substation.
SELECTION OF A KINEMATIC MODEL AND DESIGN FEATURES OF A 3D SCANNER
ILARIONOV RAYCHO(1), STOYANOV BORISLAV(2)
The paper examines the selection of a conceptual diagram for a 3D scanner of free form objects. A structure has been chosen that meets the design requirement for scanning accuracy of 25µm for parts of dimensions 500х500х350 mm. The choice of mechanical elements has determined the scanning accuracy, mechanical characteristics, as well as the required electric drive. Conclusions have been drawn about the accomplishment of precise digital images of mechanical parts ready to be used in a computer medium.
DEVELOPMENT OF A QUICK AND ACCURATE DYNAMIC IMAGE PROCESSING SOFTWARE FOR THE EFFICIENT TERRESTRIAL INDEXES’ CENTER OF GRAVITY DETERMINATION ON SPATIAL ANALYSIS SOLUTIONS – SPATIAL MANUFACTURES’ PROJECT MANAGEMENT
T. C. KOLIOPOULOS(1), C. AXINTE(2), G. KOLIOPOULOU(3)
This paper presents a quick and accurate determination of the center of gravity on a given terrestrial area. Proper image processing utilizations are presented for the examining problem in order to develop efficient civil defense works of the manufactures and effective lining of several risk management works. Moreover, useful solutions are presented for several environmental problems in order to develop an effective manufactures’ management for proper lining of particular quality control, maintenance and reclamation works. In the end, useful projections are made for the eco-design, environmental management system audit of manufactures, infrastructure works and environmental impacts’ investigation of products along their lifetime.
DEVELOPMENT OF A USEFUL IMAGE PROCESSING SOFTWARE UTILITY FOR EFFICIENT DIAGNOSTIC MONITORING OF CIRCULAR MANUFACTURES
KOLIOPOULOS T. C.(1), AXINTE C.(2), KOLIOPOULOU G.(3)
This paper presents a quick and accurate image processing monitoring method, which confronts the most common met problems in the quality assurance and safety certification of circular manufactures. An analysis is presented for mapping out life cycle diagnosis of manufactures within the field of circular geometries. Proper solutions are presented for the examining problem in order to develop effective image evaluation and mapping out methods of circular geometric manufactures. In the end, useful conclusions are made for the mapping out, risk assessment, safety certification and lining maintenance works within the management of manufactures’ technical projects.
MANAGING RISK IN AN ORGANIZATION
LABOVIÆ S. DRAGANA
There is an important component in the process of using derivatives for managing risk: effective risk management requires an effective organizational structure. The use of derivatives for managing risk can be dangerous in the absence of proper personnel, teamwork, controls and organization. The concerns of this inscription are mostly qualitative. It is easy to neglect these more subjective factors that lead to good risk management, but they are critically important. In fact, all of the quantitative models for analytical knowledge about risk management would be lost if an organization could not implement sound risk management policies.
CONTROLLING – A CONCEPT OF FUNCTIONAL MANAGEMENT WITHIN ORGANIZATIONS
LATU LAZĂR
Controlling is a procedural-type pragmatic process, which has developed mainly within large companies owing to the complexity of the economic activity. It is regarded as a management concept, i.e. coordinating planning, control, and information processing, with a view to producing a body of knowledge necessary in the decision-making process. Its function is to support the company management by coordinating planning, informing, analysis and control. This support refers to gathering as much information as possible with respect to the actions planned, their current status, the gaps occurred between planning and results by using accounting as an assessment system.
EXPERIMENTAL STAND FOR SIMULATING THE RUNNING OF A LOW POWER WIND STATION
LIVINTI PETRU, STAN GHEORGHE
This work present an experimental stand equipped with an asynchronous three phase motor with short circuited rotor, coupled to an asynchronous generator with wound rotor. Further to the experimental findings the following conclusions resulted: Depending on the variation of the wind speed and the variation of the load connected to the terminals of the phase windings of the three-phase asynchronous generator, the parameters of the electric energy supplied by the three-phase asynchronous generator can be controlled, by modifying the parameters of the energy supplying the excitation (operating) winding of the three-phase asynchronous generator. It may be affirmed that the three-phase asynchronous motors with wound rotor may be used in the construction of low power wind stations.
NEURAL NETWORKS IN THE PREDICTION OF ENERGY CONSUMPTION
NITU COSTICĂ, DOBRESCU ANDA SABENA
The energy consumption is as important in all the domains as difficult the prediction of the consumption is. The models of global energy consumption are most often nonlinear. Therefore the neural networks offer an invaluable assistance for this field. This paper presents a model for predicting the energy consumption in a building with the neural network. The application is designed in Matlab.
LINEARIZED STABILITY ANALYSIS OF FILM CONDENSATION
OLARU IONEL, CĂLIMAN RADU
A modified Yih analysis is used to investigate the stability of laminar film condensation on a vertical wall. The analysis presented leads to closed-form expressions for the wave amplification rate, the wave velocity, the neutral stability curve, and the critical Reynolds number. It is found that the condensation mass transfer rate has a dual role in the instability-inducing mechanism. Results indicate that surface tension, viscosity, and the overall effect of condensation mass transfer tend to stabilize while gravity tends to destabilize the flow. The critical distance predictions are an order of magnitude larger than the predictions from previous theories.
CONTRIBUTIONS TO THE IMPLEMENTATION OF THE TELEMETRIC PROGRAMMABLE AUTOMATS BY RTU TYPE IN THE TEHNOLOGICAL AUTOMATION LINES
OPREA CONSTANTIN, BARZ CRISTIAN, SEREGHI ALEXANDRU
The equipment RTU (Remote Terminal Unit) monopolize much more the sphere of industrial applications which necessitate the control and monitoring from distance of the processes, stored under histories form of land events, take some measures in case of damage or alert the personal. So, with help of SCADA interface (Supervisory Control And Data Acquisition) all the process can be monitored and controlled with the help of a computer. In the paper an application created with the help of the RTU Tbox equipment is presented, application being used for the monitoring of a solar installation for the processing of hot water. The application is located in a mountain area, the solar system being made up of collectors with a surface of 2x16 mp, two 500 liter reservoirs and two heat switches.
THE LABVIEW USE FOR THE REALIZATION OF THE ASSET MANAGEMENT SYSTEM IN THE ELECTROENERGETICAL DOMAIN
PUIU PETRU GABRIEL(*), BARABOI ADRIAN(**), ABABEI ȘTEFAN(*), ADAM MARCEL(**), PRUTEANU EUSEBIU(*), POPA SORIN(*)
The paper work presents an application of the asset management in the electroenergetic field. It allows on the base of real time data, the setting of a hierarchy in the assets maintenance in the energetic field
MICROCONTROLLER NEURAL NETWORK SOLUTION
ROTAR DAN, ANGHELUT MARIUS, ANDRIOAIA DRAGOS
The paper describes a solution for the neural network implement with microcontroller. One of the difficulties of the microcontroller neural network realization is the parameter acquiring and transmission. The neural network inputs consist in analog signals from the process. A solution for input signals conversion and transmission to microcontroller is presented. This method allows the remote connection of the converted numeric signals and an economic solution for neural network implement. The experimental results are presented and discussed.
CONTROL SYSTEM OF GAS COOLER OF HEAT PUMP ON CARBON DIOXIDE FOR DISTRICT HEATING SYSTEM
SIT B., JURAVLEOV A., SIT M.
The control system of the district heating system with the use of the heat pump for heating of the heating–system water arriving from combined heat power (CHP) plant is considered. Possibility of PID-controller with gain scheduling utilization with the coefficients changing depending on gas cooler mode of operation for temperature disturbances compensation of direct heating–system water is shown.