Dynamic Virtual Resource Allocation in Virtualized multi-RAT Cellular Networks

The legacy wireless systems are designed to exploit static configuration and deployment, and cannot handle the discrepancies of the spatio-temporal traffic demand. Cloud RAN (C-RAN) is a novel flexible radio technology that utilizes the virtualization concepts and can efficiently address the static deployment of conventional wireless systems. The C-RAN also leverages high radio network flexibility by introducing the network function virtualization approach to wireless networks. This paper presents a novel C-RAN platform that virtualizes and operates with full GSM and LTE systems. The presented platform is solely based on open-source and off the shelf solutions, providing easy implementation, low cost and high scalability. The paper also introduces a novel dynamic resource allocation algorithm that facilitates the C-RAN’s optimal performance in dynamic scenarios. The proposed algorithm is analyzed and validated on the presented C-RAN platform. The results of the performance analysis clearly show the advantages of the proposed dynamic resource allocation algorithm. Moreover, they prove the applicability of the C-RAN platform for variety of different scenarios.     

Fuzzy linear model for production optimization of mining systems with multiple entities

Planning and production optimization within multiple mines or several work sites (entities) mining systems by using fuzzy linear programming (LP) was studied.LP is the most commonly used operations research methods in mining engineering.After the introductory review of properties and limitations of applying LP,short reviews of the general settings of deterministic and fuzzy LP models are presented.With the purpose of comparative analysis,the application of both LP models is presented using the example of the Bauxite Basin Niksic with five mines.After the assessment,LP is an efficient mathematical modeling tool in production planning and solving many other single-criteria optimization problems of mining engineering.After the comparison of advantages and deficiencies of both deterministic and fuzzy LP models,the conclusion presents benefits of the fuzzy LP model but is also stating that seeking the optimal plan of production means to accomplish the overall analysis that will encompass the LP model approaches.     

Predicting piezometric water level in dams via artificial neural networks

The safety control of dams is based on measurements of parameters of interest such as seepage flows, seepage water clarity, piezometric levels, water levels, pressures, deformations or movements, temperature variations, loading conditions, etc. Interpretation of these large sets of available data is very important for dam health monitoring and it is based on mathematical models. Modelling seepage through geological formations located near the dam site or dam bodies is a challenging task in dam engineering. The objective of this study is to develop a feedforward neural network (FNN) model to predict the piezometric water level in dams. An improved resilient propagation algorithm has been used to train the FNN. The measured data have been compared with the results of FNN models and multiple linear regression (MLR) models that have been widely used in analysis of the structural dam behaviour. The FNN and MLR models have been developed and tested using experimental data collected during 9 years. The results of this study show that FNN models can be a powerful and important tool which can be used to assess dams.     

Computer Aided Tolerancing (CAT) platform for the design of assemblies under external and internal forces

Due to the stochastic nature of manufacturing processes, the functionality of mechanical assemblies is subject to variation defined by tolerances and manufacturing process characteristics. In many assemblies, functionality is also dependent on external and internal forces. Numerous Computer Aided Tolerancing (CAT) tools have been proposed that address tolerance analysis problems in complex mechanical assemblies; however current tools do not accommodate a general class of problem where the functionality of a design is fundamentally dependent on the effects of external and internal forces. This research addresses the limitation of CAT tools to accommodate assemblies under loading by developing a tolerance analysis platform which integrates CAD, CAE and statistical analysis tools using Process Integration and Design Optimisation (PIDO) software capabilities. The platform extends the capabilities of traditional CAT tools by enabling tolerance analysis of assemblies in which assembly characteristics are dependent on external and internal forces. To demonstrate the capabilities of the developed platform, examples of tolerance analysis problems involving external forces (compliance) and internal forces (multi-body dynamics) are presented.     

Security Analysis of the Efficient Chaos Pseudo-random Number Generator Applied to Video Encryption

Recently, chaos based pseudo-random number generator (PRNG) for video encryption was proposed. Security analysis presented in this paper reveals serious problems. Chaotic maps used in analyzed PRNG do not enhance its security due to a considerable number of initial values that lead to fixed points. Also, based on 6 known iterations, an attacker can reconstruct a secret key used in the working stage of the analyzed PRNG based on attack whose complexity is much smaller than the estimated key space. Therefore, security of the analyzed PRNG is much lower than expected and it should be used with caution. Some potential improvements of the analyzed PRNG are proposed which could eliminate perceived shortcomings of the original version.     

Correlations between submission and acceptance of papers in peer review journals

Scientometrics - This paper provides a comparative study about seasonal influence on editorial decisions for papers submitted to two peer review journals. We distinguish a specialized one, the...     

GPS telemetry of energetic-technical and technological parameters at open pit mines

Application of GPS in mining and geology has proved to be of ever increasing importance since recently. GPS is used for positioning both researching and exploitation drill holes, mining facilities, equipment, machines, when monitoring slopes and falls, mining facilities dimensioning, navigation of machines, roads tracing, etc. The paper presents a pilot system for surveillance and monitoring of energetic and technological parameters at open pit mines, developed at the “Jazovnik” open pit mine for experimental purposes. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 90–94, July–August, 2008.     

A correlation to describe interfacial heat transfer coefficient during solidification of Al–Si alloy casting

A thin wall Al–9 wt.% Si alloy casting was made in a sand mold prepared by CO₂ process. The thermal history obtained from the experiment was used to solve an inverse heat conduction problem (IHCP). The IHTC was estimated by an iterative algorithm based on the function specification method. Acquired IHTC values are given as a function of time and as a function of the casting surface temperature at the interface. It has been found that pattern of IHTC variation with casting surface temperature can be described by an equation which has been proposed as a new correlation model. In order to verify broader applicability of the proposed correlation, its use is demonstrated on the IHTC results taken from the literature.     

Impurity removal and overall rate constant during low pressure treatment of liquid silicon

The research presented analyzes the effect of low pressure on the amount and reduction of impurity elements in upgraded metallurgical grade silicon. The achieved pressure was 5 kPa in the commercial electro-resistance furnace in the magnesia and mullite refractory material. The chemical composition was determined by ICP-MS method. Elements such as Al, Fe, Mn, Cu or Zn had the highest evaporation rates where higher evaporation was achieved at higher melt temperatures. The overall rate constant was deduced for four melt temperatures indicating high values even for low melt temperatures. The interfacial boundary between Si and mullite refractory showed no dissolution of Al into the liquid Si.