Issues

Conference & Issues

Volume 28 (2022): Issue 3 (June 2022)

Volume 28 (2022): Issue 2 (June 2022)

Volume 28 (2022): Issue 1 (June 2022)

Volume 27 (2021): Issue 3 (June 2021)

Volume 27 (2021): Issue 2 (June 2021)

Volume 27 (2021): Issue 1 (June 2021)

Volume 26 (2020): Issue 3 (June 2020)

Volume 26 (2020): Issue 2 (June 2020)

Volume 26 (2020): Issue 1 (June 2020)

Volume 25 (2019): Issue 3 (June 2019)

Volume 25 (2019): Issue 2 (June 2019)

Volume 25 (2019): Issue 1 (June 2019)

Volume 24 (2018): Issue 3 (June 2018)

Volume 24 (2018): Issue 2 (June 2018)

Volume 24 (2018): Issue 1 (June 2018)

Volume 23 (2017): Issue 3 (June 2017)

Volume 23 (2017): Issue 2 (June 2017)

Volume 23 (2017): Issue 1 (June 2017)

Volume 22 (2016): Issue 3 (June 2016)

Volume 22 (2016): Issue 2 (June 2016)

Volume 22 (2016): Issue 1 (June 2016)

Volume 21 (2015): Issue 3 (June 2015)

Volume 21 (2015): Issue 2 (June 2015)

Volume 21 (2015): Issue 1 (June 2015)

Conference Details
Format
Conference
eISSN
2451-3113
ISSN
1843-6722
First Published
15 Dec 2015
Publication timeframe
3 times per year
Languages
English

Search

Volume 23 (2017): Issue 3 (June 2017)

Conference Details
Format
Conference
eISSN
2451-3113
ISSN
1843-6722
First Published
15 Dec 2015
Publication timeframe
3 times per year
Languages
English

Search

39 Articles
Open Access

Simulation and Gamification in E-Learning Technical Courses

Published Online: 22 Jul 2017
Page range: 7 - 11

Abstract

Abstract

The paper is based on the experience gained in creating eLearning courses to keep the student’s interest high, to encourage them to study additional materials in order to achieve the level of complexity proposed by the discipline objectives. The combination of specific gaming-techniques with simulation elements has been combined into designing the e-learning content. The degree of motivation and the interest in the discipline were appreciated by comparing the results obtained by students attending a blending-learning to those students who did the didactic activities in the traditional way. At present, there is a decrease in students’ interest in technical subjects. On one hand, the complexity of these disciplines is high, and moreover, in order for the students to achieve the didactic objectives of the discipline, they must make a sustained effort and combine the individual study with the explanations in the classroom.

Keywords

  • motivation for learning
  • interaction
  • simulation
  • gamification
Open Access

The Radiation Problem from a Vertical Short Dipole Antenna Above Flat and Lossy Ground: Comparison of Exact Analytical Solutions with Empirical Terrain Propagation Models and Investigation of Surface Waves

Published Online: 22 Jul 2017
Page range: 12 - 17

Abstract

Abstract

The results of a recently introduced novel solution to the well-known ‘Sommerfeld radiation problem’ are compared to those obtained through the classical Sommerfeld formulation. The method is novel in that it is entirely performed in the frequency domain, yielding simple integral expressions for the received Electromagnetic (EM) field and also in that they can end up into closed-form analytic formulas applicable to high frequencies. In this paper we compare our analytical results with existing theoretical calculations found in the literature, based on the Sommerfeld formulation. The above comparison shows good agreement in the corresponding numerical results. Furthermore, a comparison of the method to the well-known Okumura-Hata empirical model is performed in an attempt to roughly estimate the extent to which the proposed model is suitable for real-environment EM field calculations. Finally, preliminary investigations by our research group on the behaviour of the surface waves will be presented.

Keywords

  • Wireless Communications
  • Electromagnetic Waves Propagation Models
Open Access

Software Define Radio System for HF Noise Measurements

Published Online: 22 Jul 2017
Page range: 18 - 23

Abstract

Abstract

Accurate noise estimation in the HF band is a defining aspect in the evaluation of SNR for communication links. The reference document that specifies how different types of electromagnetic noise can be taken into account by radio communication system planners is the ITU-R Recommendation P.372.Meanwhile a series of studies have demonstrated that Gaussian noise in the HF band is not always valid because this band noise is strongly affected by atmospheric emission sources such as lightning impulse. This leads to the idea that a distribution suited to express the noise variance is the Bi-Kappa distribution. In addition, over the past decade, SDR devices and real-time spectrum analysers, which can be used to evaluate this noise, have registered explosive growth. This article indicates technical solutions and procedures used to estimate the noise level in the HF subband which can be used for Near Vertical Incidence Skywave (NVIS) communications and proposes a measurement system based on a SDR solution which meets these requirements.

Keywords

  • HF
  • noise
  • measurement
  • methods
  • SDR
Open Access

Determining a Particular Solution for n-th Order Linear Differential Equations with Constant Coefficients

Published Online: 22 Jul 2017
Page range: 24 - 29

Abstract

Abstract

For n-th order linear differential equations with constant coefficients, the problem to be solved is related to determining a particular solution, and then, with the general solution of n-th homogeneous linear differential equation with constant coefficients attached, to write the general solution of n-th linear differential equation with the given constant coefficients. In all the works that deal with this issue three situations are analyzed: the situation in which the free term is a polynomial P(x), the situation in which the free term is like P(x)· eα·x and lastly, the situation in which the free term is like eω·x · (P(x)· cos(β·x)+ Q(x)·sin(β·x)). In this study we aim to analyze if the free term is a combination of the three cases mentioned.

Keywords

  • n-th order linear differential equations with constant coefficients
  • n-th order homogeneous linear differential equations with constant coefficients
  • particular solution
  • general solution
Open Access

Determining a Particular Solution for the Systems of Linear Differential Equations with Constant Coefficients

Published Online: 22 Jul 2017
Page range: 30 - 36

Abstract

Abstract

As with the n-th order linear differential equations with constant coefficients, the problem to be solved is related to determining a particular solution, and then, using the general solution of the attached homogeneous system of linear differential equations with constant coefficients, to write the general solution of the initially given system. For homogeneous systems of linear differential equations with constant coefficients, the determination of the general solution is the method of eliminating or reducing which make the system a linear differential equation of the same order as that of the system, and its methods of solving it applies or the method of own values and vectors. If the system is non-homogeneous, then we also have to determine a particular solution that can be done in the same way as in the case of n-th order differential equations with constant coefficients, if the method of reduction or elimination was used, or the method of variation of constants, regardless of the method used to determine the general solution of the attached homogenous system of linear differential equations with constant coefficients. Whichever method is used, determining a particular solution for a system of linear differential equations with constant coefficients is difficult, in this study being proposed a method similar to that of n-th order linear differential equations with constant coefficients.

Keywords

  • systems of linear differential equations with constant coefficients
  • homogeneous systems of linear differential equations with constant coefficients
  • particular solution
  • general solution
Open Access

Responsive Web Design Techniques

Published Online: 22 Jul 2017
Page range: 37 - 42

Abstract

Abstract

First introduced by Ethan Marcotte in 2010 in his article Responsive Web Design, responsive design concept refers to the ability of a website to adapt to different resolutions and devices on which it is displayed (PCs, laptops, tablets, smartphones, etc.) without undergoing degradation. The site should recognize what device it is displayed on and automatically respond to user preferences. This approach comes to the aid of those who were forced to do a lot of versions of the site, so that it can be accessed from the iPad, Blackberry, Kindle, netbook, iPhone and so on[1], and becomes today a necessity. While using the same code and URL, a responsive website can provide an optimum viewing experience - without resizing, panning or scrolling on most of the devices. Web designers approached approach the new challenge with many and various solutions. To keep up with the transformations emerging in web design, this article intends to discuss the issues applied to the Land Forces Academy’s official site.

Keywords

  • responsive
  • web design
Open Access

The Decomposition Issue of a Time Series in the Forecasting Process

Published Online: 22 Jul 2017
Page range: 43 - 47

Abstract

Abstract

Decomposition of time series is the estimate and extraction of deterministic part of the series - trend, cyclical and seasonal fluctuations in the hope that the rest of the data, that is, theoretically, a random variable will be stationary random process. During the process of predicting the time series elements affects significantly on the determination of the future values, which are characterized by a low forecast error. Therefore, the purpose of this article is to identify the elements of the time series decomposition and to determine the extent to which they affect the forecasting process. Problems that often appear when you run the forecast and methods of building models and forecasts based on time series will be presented. Observations will be described on the basis of nonparametric time series modeling.

Keywords

  • time series decomposition
  • seasonal fluctuations
  • cyclicity
Open Access

Study of Operational Capabilities of Chemical Sources of Electricity Influenced by Ambient Factors

Published Online: 22 Jul 2017
Page range: 48 - 52

Abstract

Abstract

This study focuses on the possibility of using chemical sources of electricity to power smallsized equipment with a short-term activity. Physical models of the suggested battery were used and their performance was studied according to the requirements for testing the effects of both changes in temperature and reduced atmospheric pressure. Qualitative methods were implemented to define the performance of the test specimens.

Keywords

  • batteries
  • alkaline silver
  • lithium
Open Access

Characterization of 2D and 3D Rough Fractal Surfaces from Backscattered Radar Data

Published Online: 22 Jul 2017
Page range: 53 - 58

Abstract

Abstract

The scattering of electromagnetic (EM) waves, emitted by a monostatic radar, from two - dimensional (2D) rough fractal surfaces is examined by using the Kirchhoff approximation. We examine the way that the level of roughness of the fractal surface affects the backscattered EM wave captured by a radar as a function of frequency (therefore, a ‘spectral method’) and whether the roughness of the surface can be estimated from these radar measurements. The backscattering coefficient is calculated for a number of radar frequencies and for different values of the surface fractal dimension. It is found that the values of the slopes between the main lobe and the first sidelobes of the backscattering coefficient as a function of the wave number (frequency) of the incident EM waves increase with the surface fractal dimension. Therefore, we conclude that the magnitude of the above slopes provides a reliable method for the classification of the rough fractal surfaces. Furthermore, concerning three - dimensional (3D) fractal surfaces, investigations similar to the above are already performed by the authors and will be presented during the Conference. The above are also investigated in the presence of electronic noise in the radar receiver (effect of SNR values in the above proposed technique).

Keywords

  • Radar
  • Scattering of electromagnetic (EM) waves
Open Access

Methodological Framework for Capability Analysis

Published Online: 22 Jul 2017
Page range: 59 - 64

Abstract

Abstract

The article offers a methodological framework for systematic and rigorous capability analysis under uncertainty while applying basic principles of capability based planning. More specifically, it focuses on determination of capability requirements against multiple generic and specific set of force development scenarios, identification of capability mismatches, operational risk assessment steaming from capability gaps and capability prioritisation techniques and procedures. Methodological framework for capability analysis is one of the outputs of the Centre for Security and Military Strategic Studies of University of Defence in Brno institutional research project “STRATAL” - Strategic Alternatives for the Development of the Czech Armed Forces. The authors offer an innovative methodology for further discussion and best practices for development of sound defence planning process and its analytical support. Successful application of this framework depends on the quality of professional military judgement and proper use of relevant analytical techniques and procedures. In addition to that, the framework interlinks efforts in several functions of overarching defence management system, and that constitutes certain risks for generating expected outcomes e.g. insufficient coordination and harmonisation of effort, unclear responsibility for final outcomes just to name a few.

Keywords

  • capability analysis
  • capability mismatches
  • capability gaps
  • operational risks
  • prioritisation
Open Access

Electromagnetic Dosimetry of Radiofrequency Portable Transceivers Used in Front of the Face

Published Online: 22 Jul 2017
Page range: 65 - 70

Abstract

Abstract

Portable transceivers emitting in the UHF radiofrequency band are sources of human electromagnetic exposure, when located in front of the face. Three output power levels were tested while the exposed target was a phantom filled with dielectric liquid simulating average human head behavior at the used frequency of 446 MHz. A flat phantom and a head phantom were scanned by an automatic E-field probe robot, based on the standardized procedure, in order to report specific absorption rates of energy deposition in the head. A discussion on the obtained results is provided, together with a comparison with other similar results in the literature. Consequences upon the safe use of such devices by public or by occupational personnel in the proximity of the brain and eyes are underlined.

Keywords

  • SAR
  • RF dosimetry
  • human exposure
  • near field
  • portable transceiver
Open Access

Upon Bulk Cavitation Appearing in Underwater Explosions

Published Online: 22 Jul 2017
Page range: 71 - 78

Abstract

Abstract

This paper presents some results of the author’s researching in connection with SPH (smoothed particle hydrodynamics) method and underwater explosion numerical modelling. All about cavitation fundamentals are considered known and about cavitation effects upon the structures. The authors, deeply preoccupied in using of SPH method, as well in modelling of the underwater explosion effects upon structures, had to take into consideration the bulk cavitation. A main issue in this study was the knowing of the bulk cavitation domain and its characteristic parameters. Such researching was possible to be successfully carried out, only by using of the SPH method. Finally, the paper presents the relations and the working way for knowing of the bulk cavitation domain and also a numerical model using SPH method is presented. The numerical example regarding shape and dimensions of the bulk cavitation is presented together putting in evidence of some parameters which can make damages upon a structure that is in the bulk cavitation area.

Keywords

  • bulk cavitation
  • shock wave
  • SPH method
  • underwater explosion
Open Access

Analyses of Face Recognition Rate Using Holistic Methods

Published Online: 22 Jul 2017
Page range: 79 - 83

Abstract

Abstract

The paper focuses on the analysis of holistic facial recognition rates obtained by changing the parameters related to the number of components and the number of images for the same subject in the training set. It has been observed that, regardless of the method used, choosing a small number of samples for the training set does not lead to acceptable results. The recognition rate for using the PCA algorithm is directly influenced by the number of samples and by the size of the feature vector. Thus, if all the features were retained and the number of images in the training set was high, 95% rates were obtained. Similarly, in the case of the extraction of vectors of variable dimensions with DCT and the use of a neural network for classification, the obtained rates were not satisfactory for a small number of samples in the training set.

Keywords

  • face recognition
  • PCA
  • DCT
  • Neural Network
Open Access

Aspects on the Influence of Starting the Own Services Consumers of an Energy Group with Unit of 330 MW on the Power Supply

Published Online: 22 Jul 2017
Page range: 84 - 89

Abstract

Abstract

The elaborated paper had as support a study case on the monitoring of the supply voltage on a busbar system, which feeds the electric motors that enters into the configuration of the technological flow of electricity production of an energy group with a unitary power of 330 MW. In the start-up phase of the energy groups with a unitary power of 330 MW, the consumers of their own services are supplied with electricity by means of general service transformers interconnected to the National Energy System.

Keywords

  • power supply
  • own services
  • bus bars
  • main bus systems
  • monitoring
  • energy group
Open Access

Environmental Influence on Divers’ Health

Published Online: 22 Jul 2017
Page range: 90 - 102

Abstract

Abstract

In contemporary society we all are deeply affected by the air we breathe, the water we drink, the food we eat, and, not in the least, along with other factors, by the stress we encounter in our everyday life.Apart from this general issue this paper aims to raise awareness on a specific problem concerning divers life and training, namely on how the environment can affect their health. The clinical and statistical studies observed the incidence of pathological changes that occur in people exposed to hyperbaric environment, which more often than not can be the case of professional divers. What we also aim at is to find solutions for the elimination and avoidance of such risk factors

Keywords

  • hyperbaric environment
  • pathological changes
  • breathing gas mixture
  • water
Open Access

Theoretical and Practical Study on Divers’ Diet During Their Training Practice

Published Online: 22 Jul 2017
Page range: 103 - 113

Abstract

Abstract

The hereby paper briefly presents the specific objectives announced, the ways in which they have been carried out, the measures taken by the Divers Center, the divers’ awareness towards their duties, further measures to be taken, and finally the way all these are applied to divers’ everyday life. The paper concludes with interpretations, comments, final considerations on the research and development theme approached by the CPSA laboratory, along with future developments within the area of research

Keywords

  • diver’s feeding regime/diet
  • effort
  • weight index
  • improper nutrition
Open Access

Mobile Phone User Exposure Assessment to UMTS and LTE Signals at Mobile Data Turn on by Applying an Original Method

Published Online: 22 Jul 2017
Page range: 114 - 119

Abstract

Abstract

In order to provide assessment of mobile phone user exposure to electromagnetic fields emitted in the close vicinity of a mobile device we have measured real life UMTS and LTE signals at mobile data turn on. The paper presents some preliminary results of mobile phone user exposure assessment at mobile data turn by making use of a non-standardized procedure that enables the calculus of the radiated signal energy and duty cycle. Our results sustain that higher user exposure is expected within the first minute after mobile data is switched on as higher duty cycles and more than a third of the total radiated energy is found in this time period, as compared to the total signal monitoring time. Authors expect increased exposure if other application services are launched within this time frame. Moreover, special attention should be paid to user exposure assessment in the case of active call services with mobile data turned on. Because SAR is currently the sole standardized metrics in dosimetry, the authors propose the use of the measured signal radiated energy as well as the calculated duty cycle as complementary indicators of user exposure to electromagnetic fields in order to provide a more comprehensive view on mobile phone radiation exposure.

Keywords

  • exposure assessment
  • radiated power
  • mobile data turn on
  • UMTS
  • LTE
Open Access

Numerical Analyis of the Low-Altitude Air Turbulence Mathematical Models Used in Modelling of the Spatial Motion of the Small Unmanned Aerial Vehicles

Published Online: 22 Jul 2017
Page range: 120 - 130

Abstract

Abstract

Unmanned Aerial Vehicles designed and manufactured often with unknown origin but available in sale of the model aircraft market rarely deals with weather circumstances and conditions defining clearances for safe air operations of the UAV. UAVs used in low-altitude flight missions are often threatened by atmospheric turbulences leading either to high angle-of-attack (AoA) or leading to the stall of the UAV. There are many mathematical models well-known and widely applied in piloted aircraft aviation when to simulate atmospheric turbulences affecting spatial motion of the aircraft. This paper targets to evaluate and simulate numerically the low-altitude air turbulences, and, to examine the vertical gust speed of the small UAV. The UAV behaviour examined numerically will support to find weather clearances ensuring UAV flight safety having the level equal or higher to that level of manned aircraft regulated well-before. A computer code in MATLAB environment is created to support numerical analysis of the small UAV behaviour in low altitude atmospheric turbulence.

Keywords

  • air turbulence
  • modelling atmospheric turbulences
  • small UAV in turbulent air
  • numerical simulation
Open Access

Reducing the Phase-Noise In ΔΣ Fractional-N Synthezis – A Simulink Model

Published Online: 22 Jul 2017
Page range: 131 - 134

Abstract

Abstract

The resolution in fractional-N synthesis results as a fractional part of the reference frequency. This category of synthesizers permits a greater fref and a smaller N, a larger loop bandwidth, faster lock times and reduced output phase-noise. In ΔΣ fractional-N PLL’s the main problem is the specific quantization noise. To reduce them many techniques are used. The paper presents a Simulink model of the influence of the requantisation in the phase-noise cancellation process.

Keywords

  • frequency synthesis
  • ΔΣ modulator
  • phase-noise
Open Access

Computer Simulation - Efficient Tool of Crisis Management

Published Online: 22 Jul 2017
Page range: 135 - 141

Abstract

Abstract

The paper presents an analytical evaluation of the advantages of computer simulation of emergency situations within crisis management processes optimization. It affirms the efficiency of the preparation of crisis staffs, their coordination, communication and cooperation on the practical example of the SIMEX simulation tool.

Keywords

  • crisis management
  • communication
  • exercise
  • simulation
Open Access

Cargo Securing During Transportation – Using Extreme Values

Published Online: 22 Jul 2017
Page range: 142 - 147

Abstract

Abstract

This article analyses possibilities for securing cargo on selected military truck - middle cargo terrain Tatra T-810 DO AŠ. It presents a model of cargo securing using lashing straps, which is based on the minimum and maximum angle possible between lashing strap and horizontal plane where mounted. It compares inertial forces in the x-axis and y-axis, where the data source is in one case the basal variant of measured values of acceleration coefficients and in the second case normatively set values of acceleration coefficients. Both outputs - the size of the inertial forces in both axes are compared and a set of recommendations for cargo securing is formulated.

Keywords

  • transportation
  • cargo securing
  • acceleration coefficient
  • fastening strap
Open Access

Cargo Securing and Accident Rate in the Army of the Czech Republic

Published Online: 22 Jul 2017
Page range: 148 - 154

Abstract

Abstract

The article analyses the evolution of the accident rate in terms of the Army of the Czech Republic during last 6 years (2010-2015) and examines selected causes of vehicle accidents. In the context of the comparison of selected methods of cargo securing an analysis of potential risks in cargo securing on trucks of the Army of the Czech Republic has been done. A simple model of cargo securing on selected truck was created for these purposes. The model takes into account values measured in the field in comparison to conventional transport performed on highway and 2nd class road. Statistical analysis of the evaluation values of the coefficients of acceleration, which serves as a data source of the presented model, is included.

Keywords

  • transportation
  • cargo security
  • modelling
  • accident rate
Open Access

Unmanned Aerial Vehicle Influence of Troops Leading Procedure

Published Online: 22 Jul 2017
Page range: 155 - 162

Abstract

Abstract

Unmanned aerial vehicles, drones and other similar equipment are having a boom nowadays. Moreover, the usage of those modern technologies is also significant within armies. Unmanned aerial vehicles are extensively use within most of the military activities all over the world mainly on the battalion level and above. This paper is focused to discuss the usage of this technology on tactical level, particularly by squad and squad size units. The paper deals mainly with influence of unmanned aerial vehicles on troops leading procedure. The main methods of this paper are outcomes from the realized experiment. It shows on examples specific impact on all steps of the troops leading procedure. The experiment revealed interesting data and some possible conclusion were made. The primarily target of this paper is experience military personnel dealing with this topic. The paper should open broad discussion focused on all steps of troops leading procedure and outline the possible way of troops leading procedure update. Unmanned aerial vehicles, drones and other modern technology providing almost online information to the squad leader could significantly influence all steps of the troop leading procedure, safe preparation time as well as lives of the troops.

Keywords

  • unmanned aerial vehicle
  • troops leading procedure
  • small unit tactics
  • mission
  • squad
Open Access

Challenges for Sample Preparation and Analysis of New Matrices During the OPCW Proficiency Tests

Published Online: 22 Jul 2017
Page range: 163 - 167

Abstract

Abstract

In the OPCW Proficiency Tests usually two sets of three samples each (test sample, control, blank) are sent for analysis, with no indication for the type of the sample. Each set of samples can be prepared in a different matrix, with organic solvent, water and soil as the most frequent ones. Thus each sample has to be analyzed like a test sample. Participants are requested to identify any chemical contained in the schedules of the Chemical Weapons Convention plus all the degradation products that can originate from them; this involves millions of possible chemicals. Usually, a spiking level of ≈10 ppm is applied. Only chemicals that are considered relevant within the scenario of the proficiency test are to be reported. The choice of sample preparation method strongly depends on the composition of the sample and on the requirements for the different analytical techniques employed in the screening and analysis. Because the sample composition of proficiency test samples is unknown, no target compound sample preparation methods can be applied. New matrices, never used in a PT before, required participants to develop new or to adopt existing sample preparation methods. The new matrices from the 38th OPCW PT were linked to food, biodiesel like used cooking oil methyl ester and a 2% Agar-agar solution (solid gel). Aluminium metal and artificial rainwater chosen to provide matrix challenge for the 40th OPCW PT. The paper provides the challenges that are generated by the new and complex matrices, how to work up gel sample, the tendency of biodiesel to form emulsions, how to sub-sample “metal fragments”, and the method of extractions.

Keywords

  • OPCW
  • matrices
  • proficiency test
  • trichloronitromethane
  • 3-Quinuclidinyl benzilate
Open Access

The Influence of Temperature Changes on the Eigen - Frequencies and Mode Shapes for Rectangular Plates Clamped on the Contour

Published Online: 22 Jul 2017
Page range: 168 - 173

Abstract

Abstract

The alysis of free vibrations on rectangular plates with mixed conditions of buckling in the thermal environment is carried out by means of the 3D elasticity theory. In this paper there has been analyzed by the finite element method (FEM), the mode shape and the eigen-frequencies for a rectangular plate clamped on the contour for different temperatures. In this analysis successive heat degrees have been used, this fact helping to find the critical values in which the frequencies were at zero and to correlate these temperatures with the values obtained from the static analysis The temperature rise, the material graded index and the geometrical parameters on the eigen-frequencies were studied.

Keywords

  • temperature changes
  • eigen-frequencies
  • mode shapes
  • rectangular plates
  • FEM
Open Access

Numerical Modeling and Experimental Research of the Perforation Phenomenon of Certain Materials Used for Individual Protection by Bullets

Published Online: 22 Jul 2017
Page range: 174 - 179

Abstract

Abstract

The paper captures two aspects related to the phenomenon of impact between bullets and different types of materials used for the individual protection of the militaries, for the same type of ammunition and for the same configuration of the ballistic protection system, both in the case of the activity of experimental shooting range testing, as well as in the case of the modeling and simulation of the impact between the bullet and the protection materials.

Keywords

  • perforation
  • bullet
  • protection materials
  • armor
Open Access

Experimental Investigations on the Stress State in the Bearing Structure of a Special Wagon to Transport Liquid Iron

Published Online: 22 Jul 2017
Page range: 180 - 187

Abstract

Abstract

In order to increase productivity, to reduce energy consumption and for environmental protection, a special wagon intended for the transport of liquid pig iron, in steel mills, it was designed and manufactured. This wagon consists of an especial chamotted torpedo, with a capacity of 300 tons, rested, at each end, by means of a box beam, on two buggies, with four axles each one. To evaluate the mechanical behavior of this wagon during service, its prototype was investigated experimentally in terms of the stress and strain state. Due to difficulties encountered related to the long duration of loading and unloading time of the torpedo pot with liquid cast iron and due to very large dimensions of the carriage gauge, experimental investigations were performed on the torpedo pot and box beam models, manufactured at scale. The buggy structure was investigated on a special stand, set up in the laboratory of Strength of Materials Department of the Polytechnic University of Bucharest. The torpedo pot and box beam were investigated using two combined experimental techniques (brittle coatings technique and resistive strain gauge technique). Brittle coatings technique was used to identify the principal stresses directions, which then were applied electro-resistive transducers. Using strain gauge amplifiers the principal strains were measured, and principal stresses in measurement points were calculated. The results of these studies have led to changes of constructive solutions in the case of some substructures, contributing to increase the operational safety of the wagon.

Keywords

  • stress state
  • box beam
  • bogie
  • strain gauge
  • brittle coatings
Open Access

Design and Testing of an Unguided Rocket with Thermobaric Warhead for Multiple Launcher System

Published Online: 22 Jul 2017
Page range: 188 - 198

Abstract

Abstract

This paper presents the development, testing and evaluation of a new unguided rocket equipped with a thermobaric warhead. The aim of the research was to design the ammunition to be integrated with an existing multiple launch rocket system. This condition introduced limitations of dimensions, mass and mass distribution. The experimental work consisted also in optimisation of the thermobaric composition and configuration. The resulting ammunition was tested for determination of effective range and precision. The destructive effect was evaluated by live firing against non-armoured vehicles and masonry light structures.

Keywords

  • thermobaric
  • munitions
  • blast
  • energetic materials
Open Access

Numerical Modelling of Terminal Ballistic for 40 × 46 mm Lesslethal Kinetic Grenade

Published Online: 22 Jul 2017
Page range: 199 - 203

Abstract

Abstract

This paper presents the terminal ballistics of a 40×46mm less lethal grenade. The aim of the research was to determine the kinetic energy applied to the surface in the moment of impact and also the non-lethal characteristic of this ammunition. 40 × 46 mm less-lethal kinetic grenade is made of resilient material that increases its surface in the moment of impact in order to dissipate the kinetic energy developed

Keywords

  • 40×46 mm
  • less lethal
  • terminal ballistics
Open Access

Design and Performance Characteristics of New Female Bulletproof Vests

Published Online: 22 Jul 2017
Page range: 204 - 207

Abstract

Abstract

The new female bulletproof vest was designed with a superior female fit, this body armour providing a good balance between protection and comfort. One of the new issues in designing the female ballistic vest consists in taking into account the shape and bras size of Romanian female body, based on anthropometric survey using the 3D scanner technology. This bulletproof vest will provide comfort and mobility with the same or superior ballistic resistance properties versus standard body armour equipment. The ballistic performance parameters have been evaluated, in agreement with the international standards, in specialized laboratories of the Romanian MoD.

Keywords

  • female bulletproof
  • vest
  • body armour
Open Access

Maintenance System Research for Armored Vehicles in Peacekeeping Operation as Close Queueing System in Dynamic Regime

Published Online: 22 Jul 2017
Page range: 208 - 212

Abstract

Abstract

The maintenance system for wheel vehicles of 4th infantry battalion from Iraqi stable forces is studied in this article as a close queuing system. The differential equations of the dynamic functioning of the system are derived and solved numerically. The results of the dynamic characteristics and loading of the system are analyzed and compared with the results in stationary regime.

Keywords

  • Queuing model
  • maintenance
Open Access

Evacuation Algorithm of Armoured Vehicles

Published Online: 22 Jul 2017
Page range: 213 - 218

Abstract

Abstract

This publication analyses the main stages of evacuation of stuck and mind-bound armoured vehicles. A methodology and an algorithm have been developed for towing vehicles in cases of insufficient traction power of the traction engine.

Keywords

  • evacuation
  • armoured vehicles
Open Access

Virtual Model of the Terrain – A Reality Available to Everyone

Published Online: 22 Jul 2017
Page range: 219 - 223

Abstract

Abstract

Planning warfare at the tactical level, establishing and choosing the best course of action involves among other things, a precise knowledge of the configuration of the field in the area of engagement, disposition natural and artificial planimetric elements (layout) and their influence on warfare. Classical sandbox or sand table, tree branches, stones and other materials will be replaced with land simulation methods which located in the virtual sphere with minimal hardware and software investment and which will generate a report outstanding results with extremely high efficiency

Keywords

  • terrain
  • analysis
  • virtual
  • sandbox
Open Access

Resistance of Barrier Materials Against Toxic Compounds Permeation and Its Evaluation in Accordance with New European Norms

Published Online: 22 Jul 2017
Page range: 224 - 233

Abstract

Abstract

Study of barrier material resistance against permeation of toxic compounds belongs to a category of chemical warfare agents and toxic industrial chemicals are permanently insufficiently solved problems. This work deals with changes in approaches to testing barrier materials against toxic compounds permeation in static and dynamic conditions. An aim of this information is to describe specifications of cancelled norms of ČSN EN ISO 6529 (2002) a ČSN EN 374-3 (2004) with newly established norms ČSN EN 16523-1 a 16523-2 (2015). Authors focused on specification and comments of changes in such parts of norms concerning their scope, terms and definitions. A selected problem was solved with the help of analyse of newly established norms in a form of comments. Conditions for specification of understanding of mentioned problems in a context of established or occasionally prepared methods of testing resistance barrier materials against toxic compounds permeation have been formed with elaborated research.

Keywords

  • Protective clothing
  • barrier material
  • toxic compound
  • permeation
  • norm
Open Access

Chemical Resistance of Textile with a Butyl-Rubber Polymeric Mixture Against Decontamination Mixture on the Base of Chlorinated Aliphatic and Aromatic Hydrocarbons

Published Online: 22 Jul 2017
Page range: 234 - 242

Abstract

Abstract

Used equipment for providing hermetic isolative protection of the Czech Armed Forces Chemical Corps specialists’ body surface is currently solved with the employment of a mixture based on butyl-rubber. By producers declared protective properties of used barrier material does not mention a potential influence of decontamination mixtures and their components on the change of protective properties. A paper deals with selected chemical properties of butyl-rubber and points to the destructive influences of selected decontamination mixtures on protective textile used to production of isolative hermetic protective equipment. Study of barrier material chemical resistance against permeation of selected chemical compounds and mixtures creates the base presumption for evaluation of its usability.

Keywords

  • decontamination
  • decontamination mixture
  • breakthrough time
  • diffusion
Open Access

Experimental Research on the Manufactureof Parts Composing a Technical System Using Polymer Composite Materials

Published Online: 22 Jul 2017
Page range: 243 - 250

Abstract

Abstract

The article presents experimental research conducted by the authors for use of polymer composite materials to manufacture pressure parts of subassemblies composition of technical systems, currently manufactured from nonferrous materials. The research aimed to identify and establish a manufacturing technology specific for polymer composite materials and conducting testing and verification of resistance of manufactured parts, including their real operation conditions under pressure. The final part of the article highlights the authors’ conclusions, insisting on the advantages and disadvantages of the proposed method.

Keywords

  • polymer materials
  • FIBROPLAST BURNAS STI-20material
  • mechanical properties
Open Access

Selected Aspects of Vehicle Born Improvized Explosive Devices

Published Online: 22 Jul 2017
Page range: 251 - 256

Abstract

Abstract

The paper focuses on the analysis of the current highly dangerous tools of destruction, used mostly by insurgents and terrorists, especially in asymmetric warfare. Vehicles usually loaded with explosives (mostly homemade explosive), driven by suicide bombers are a significant threat to troops and the civilian population, not only in high risk areas. Analysis of the available incidents of this type, and available response to an incident mentioned in this article, it becomes the basic portfolio data for the design of effective elimination or at least reduction of the destructive effect, especially on soft targets.

Keywords

  • IED
  • VBIED
  • Tactics
  • Barrier
Open Access

Influence of the Shock Wave on the Hybrid Ballistic Gelatin

Published Online: 22 Jul 2017
Page range: 257 - 261

Abstract

Abstract

Forensic ballistic tests involve the use of various ballistic gelatins and soaps. Their use is restrained due to several important factors: their synthesis strategy, their availability at room temperature and their rapid degradation even when kept in cold places. The importance of human torso surrogates translates in the facility to verify various ballistic factors impact, such as shock wave or fragments. In the first case, the use of piezoelectric transducers and accelerometers inside torso surrogates helps in defining safety distances and materials for individual protection equipment.

Keywords

  • forensics
  • materials
  • ballistics
  • shock wave
Open Access

Methods For Determination of the Parameters of a Machine Gun Suspension Mounted on an Armoured Vehicle

Published Online: 22 Jul 2017
Page range: 262 - 267

Abstract

Abstract

The following report shows methods for determination of the coefficients of stiffness and damping, for softening the vibrations, which ensue in an armoured vehicle’s suspension from the shooting of a mounted machine-gun. The methods are based on a model of the movement smoothness, in which is additionally included the signal of the machine gun’s recoil.

Keywords

  • shooting
  • machine gun suspension
  • stiffness
  • damping
39 Articles
Open Access

Simulation and Gamification in E-Learning Technical Courses

Published Online: 22 Jul 2017
Page range: 7 - 11

Abstract

Abstract

The paper is based on the experience gained in creating eLearning courses to keep the student’s interest high, to encourage them to study additional materials in order to achieve the level of complexity proposed by the discipline objectives. The combination of specific gaming-techniques with simulation elements has been combined into designing the e-learning content. The degree of motivation and the interest in the discipline were appreciated by comparing the results obtained by students attending a blending-learning to those students who did the didactic activities in the traditional way. At present, there is a decrease in students’ interest in technical subjects. On one hand, the complexity of these disciplines is high, and moreover, in order for the students to achieve the didactic objectives of the discipline, they must make a sustained effort and combine the individual study with the explanations in the classroom.

Keywords

  • motivation for learning
  • interaction
  • simulation
  • gamification
Open Access

The Radiation Problem from a Vertical Short Dipole Antenna Above Flat and Lossy Ground: Comparison of Exact Analytical Solutions with Empirical Terrain Propagation Models and Investigation of Surface Waves

Published Online: 22 Jul 2017
Page range: 12 - 17

Abstract

Abstract

The results of a recently introduced novel solution to the well-known ‘Sommerfeld radiation problem’ are compared to those obtained through the classical Sommerfeld formulation. The method is novel in that it is entirely performed in the frequency domain, yielding simple integral expressions for the received Electromagnetic (EM) field and also in that they can end up into closed-form analytic formulas applicable to high frequencies. In this paper we compare our analytical results with existing theoretical calculations found in the literature, based on the Sommerfeld formulation. The above comparison shows good agreement in the corresponding numerical results. Furthermore, a comparison of the method to the well-known Okumura-Hata empirical model is performed in an attempt to roughly estimate the extent to which the proposed model is suitable for real-environment EM field calculations. Finally, preliminary investigations by our research group on the behaviour of the surface waves will be presented.

Keywords

  • Wireless Communications
  • Electromagnetic Waves Propagation Models
Open Access

Software Define Radio System for HF Noise Measurements

Published Online: 22 Jul 2017
Page range: 18 - 23

Abstract

Abstract

Accurate noise estimation in the HF band is a defining aspect in the evaluation of SNR for communication links. The reference document that specifies how different types of electromagnetic noise can be taken into account by radio communication system planners is the ITU-R Recommendation P.372.Meanwhile a series of studies have demonstrated that Gaussian noise in the HF band is not always valid because this band noise is strongly affected by atmospheric emission sources such as lightning impulse. This leads to the idea that a distribution suited to express the noise variance is the Bi-Kappa distribution. In addition, over the past decade, SDR devices and real-time spectrum analysers, which can be used to evaluate this noise, have registered explosive growth. This article indicates technical solutions and procedures used to estimate the noise level in the HF subband which can be used for Near Vertical Incidence Skywave (NVIS) communications and proposes a measurement system based on a SDR solution which meets these requirements.

Keywords

  • HF
  • noise
  • measurement
  • methods
  • SDR
Open Access

Determining a Particular Solution for n-th Order Linear Differential Equations with Constant Coefficients

Published Online: 22 Jul 2017
Page range: 24 - 29

Abstract

Abstract

For n-th order linear differential equations with constant coefficients, the problem to be solved is related to determining a particular solution, and then, with the general solution of n-th homogeneous linear differential equation with constant coefficients attached, to write the general solution of n-th linear differential equation with the given constant coefficients. In all the works that deal with this issue three situations are analyzed: the situation in which the free term is a polynomial P(x), the situation in which the free term is like P(x)· eα·x and lastly, the situation in which the free term is like eω·x · (P(x)· cos(β·x)+ Q(x)·sin(β·x)). In this study we aim to analyze if the free term is a combination of the three cases mentioned.

Keywords

  • n-th order linear differential equations with constant coefficients
  • n-th order homogeneous linear differential equations with constant coefficients
  • particular solution
  • general solution
Open Access

Determining a Particular Solution for the Systems of Linear Differential Equations with Constant Coefficients

Published Online: 22 Jul 2017
Page range: 30 - 36

Abstract

Abstract

As with the n-th order linear differential equations with constant coefficients, the problem to be solved is related to determining a particular solution, and then, using the general solution of the attached homogeneous system of linear differential equations with constant coefficients, to write the general solution of the initially given system. For homogeneous systems of linear differential equations with constant coefficients, the determination of the general solution is the method of eliminating or reducing which make the system a linear differential equation of the same order as that of the system, and its methods of solving it applies or the method of own values and vectors. If the system is non-homogeneous, then we also have to determine a particular solution that can be done in the same way as in the case of n-th order differential equations with constant coefficients, if the method of reduction or elimination was used, or the method of variation of constants, regardless of the method used to determine the general solution of the attached homogenous system of linear differential equations with constant coefficients. Whichever method is used, determining a particular solution for a system of linear differential equations with constant coefficients is difficult, in this study being proposed a method similar to that of n-th order linear differential equations with constant coefficients.

Keywords

  • systems of linear differential equations with constant coefficients
  • homogeneous systems of linear differential equations with constant coefficients
  • particular solution
  • general solution
Open Access

Responsive Web Design Techniques

Published Online: 22 Jul 2017
Page range: 37 - 42

Abstract

Abstract

First introduced by Ethan Marcotte in 2010 in his article Responsive Web Design, responsive design concept refers to the ability of a website to adapt to different resolutions and devices on which it is displayed (PCs, laptops, tablets, smartphones, etc.) without undergoing degradation. The site should recognize what device it is displayed on and automatically respond to user preferences. This approach comes to the aid of those who were forced to do a lot of versions of the site, so that it can be accessed from the iPad, Blackberry, Kindle, netbook, iPhone and so on[1], and becomes today a necessity. While using the same code and URL, a responsive website can provide an optimum viewing experience - without resizing, panning or scrolling on most of the devices. Web designers approached approach the new challenge with many and various solutions. To keep up with the transformations emerging in web design, this article intends to discuss the issues applied to the Land Forces Academy’s official site.

Keywords

  • responsive
  • web design
Open Access

The Decomposition Issue of a Time Series in the Forecasting Process

Published Online: 22 Jul 2017
Page range: 43 - 47

Abstract

Abstract

Decomposition of time series is the estimate and extraction of deterministic part of the series - trend, cyclical and seasonal fluctuations in the hope that the rest of the data, that is, theoretically, a random variable will be stationary random process. During the process of predicting the time series elements affects significantly on the determination of the future values, which are characterized by a low forecast error. Therefore, the purpose of this article is to identify the elements of the time series decomposition and to determine the extent to which they affect the forecasting process. Problems that often appear when you run the forecast and methods of building models and forecasts based on time series will be presented. Observations will be described on the basis of nonparametric time series modeling.

Keywords

  • time series decomposition
  • seasonal fluctuations
  • cyclicity
Open Access

Study of Operational Capabilities of Chemical Sources of Electricity Influenced by Ambient Factors

Published Online: 22 Jul 2017
Page range: 48 - 52

Abstract

Abstract

This study focuses on the possibility of using chemical sources of electricity to power smallsized equipment with a short-term activity. Physical models of the suggested battery were used and their performance was studied according to the requirements for testing the effects of both changes in temperature and reduced atmospheric pressure. Qualitative methods were implemented to define the performance of the test specimens.

Keywords

  • batteries
  • alkaline silver
  • lithium
Open Access

Characterization of 2D and 3D Rough Fractal Surfaces from Backscattered Radar Data

Published Online: 22 Jul 2017
Page range: 53 - 58

Abstract

Abstract

The scattering of electromagnetic (EM) waves, emitted by a monostatic radar, from two - dimensional (2D) rough fractal surfaces is examined by using the Kirchhoff approximation. We examine the way that the level of roughness of the fractal surface affects the backscattered EM wave captured by a radar as a function of frequency (therefore, a ‘spectral method’) and whether the roughness of the surface can be estimated from these radar measurements. The backscattering coefficient is calculated for a number of radar frequencies and for different values of the surface fractal dimension. It is found that the values of the slopes between the main lobe and the first sidelobes of the backscattering coefficient as a function of the wave number (frequency) of the incident EM waves increase with the surface fractal dimension. Therefore, we conclude that the magnitude of the above slopes provides a reliable method for the classification of the rough fractal surfaces. Furthermore, concerning three - dimensional (3D) fractal surfaces, investigations similar to the above are already performed by the authors and will be presented during the Conference. The above are also investigated in the presence of electronic noise in the radar receiver (effect of SNR values in the above proposed technique).

Keywords

  • Radar
  • Scattering of electromagnetic (EM) waves
Open Access

Methodological Framework for Capability Analysis

Published Online: 22 Jul 2017
Page range: 59 - 64

Abstract

Abstract

The article offers a methodological framework for systematic and rigorous capability analysis under uncertainty while applying basic principles of capability based planning. More specifically, it focuses on determination of capability requirements against multiple generic and specific set of force development scenarios, identification of capability mismatches, operational risk assessment steaming from capability gaps and capability prioritisation techniques and procedures. Methodological framework for capability analysis is one of the outputs of the Centre for Security and Military Strategic Studies of University of Defence in Brno institutional research project “STRATAL” - Strategic Alternatives for the Development of the Czech Armed Forces. The authors offer an innovative methodology for further discussion and best practices for development of sound defence planning process and its analytical support. Successful application of this framework depends on the quality of professional military judgement and proper use of relevant analytical techniques and procedures. In addition to that, the framework interlinks efforts in several functions of overarching defence management system, and that constitutes certain risks for generating expected outcomes e.g. insufficient coordination and harmonisation of effort, unclear responsibility for final outcomes just to name a few.

Keywords

  • capability analysis
  • capability mismatches
  • capability gaps
  • operational risks
  • prioritisation
Open Access

Electromagnetic Dosimetry of Radiofrequency Portable Transceivers Used in Front of the Face

Published Online: 22 Jul 2017
Page range: 65 - 70

Abstract

Abstract

Portable transceivers emitting in the UHF radiofrequency band are sources of human electromagnetic exposure, when located in front of the face. Three output power levels were tested while the exposed target was a phantom filled with dielectric liquid simulating average human head behavior at the used frequency of 446 MHz. A flat phantom and a head phantom were scanned by an automatic E-field probe robot, based on the standardized procedure, in order to report specific absorption rates of energy deposition in the head. A discussion on the obtained results is provided, together with a comparison with other similar results in the literature. Consequences upon the safe use of such devices by public or by occupational personnel in the proximity of the brain and eyes are underlined.

Keywords

  • SAR
  • RF dosimetry
  • human exposure
  • near field
  • portable transceiver
Open Access

Upon Bulk Cavitation Appearing in Underwater Explosions

Published Online: 22 Jul 2017
Page range: 71 - 78

Abstract

Abstract

This paper presents some results of the author’s researching in connection with SPH (smoothed particle hydrodynamics) method and underwater explosion numerical modelling. All about cavitation fundamentals are considered known and about cavitation effects upon the structures. The authors, deeply preoccupied in using of SPH method, as well in modelling of the underwater explosion effects upon structures, had to take into consideration the bulk cavitation. A main issue in this study was the knowing of the bulk cavitation domain and its characteristic parameters. Such researching was possible to be successfully carried out, only by using of the SPH method. Finally, the paper presents the relations and the working way for knowing of the bulk cavitation domain and also a numerical model using SPH method is presented. The numerical example regarding shape and dimensions of the bulk cavitation is presented together putting in evidence of some parameters which can make damages upon a structure that is in the bulk cavitation area.

Keywords

  • bulk cavitation
  • shock wave
  • SPH method
  • underwater explosion
Open Access

Analyses of Face Recognition Rate Using Holistic Methods

Published Online: 22 Jul 2017
Page range: 79 - 83

Abstract

Abstract

The paper focuses on the analysis of holistic facial recognition rates obtained by changing the parameters related to the number of components and the number of images for the same subject in the training set. It has been observed that, regardless of the method used, choosing a small number of samples for the training set does not lead to acceptable results. The recognition rate for using the PCA algorithm is directly influenced by the number of samples and by the size of the feature vector. Thus, if all the features were retained and the number of images in the training set was high, 95% rates were obtained. Similarly, in the case of the extraction of vectors of variable dimensions with DCT and the use of a neural network for classification, the obtained rates were not satisfactory for a small number of samples in the training set.

Keywords

  • face recognition
  • PCA
  • DCT
  • Neural Network
Open Access

Aspects on the Influence of Starting the Own Services Consumers of an Energy Group with Unit of 330 MW on the Power Supply

Published Online: 22 Jul 2017
Page range: 84 - 89

Abstract

Abstract

The elaborated paper had as support a study case on the monitoring of the supply voltage on a busbar system, which feeds the electric motors that enters into the configuration of the technological flow of electricity production of an energy group with a unitary power of 330 MW. In the start-up phase of the energy groups with a unitary power of 330 MW, the consumers of their own services are supplied with electricity by means of general service transformers interconnected to the National Energy System.

Keywords

  • power supply
  • own services
  • bus bars
  • main bus systems
  • monitoring
  • energy group
Open Access

Environmental Influence on Divers’ Health

Published Online: 22 Jul 2017
Page range: 90 - 102

Abstract

Abstract

In contemporary society we all are deeply affected by the air we breathe, the water we drink, the food we eat, and, not in the least, along with other factors, by the stress we encounter in our everyday life.Apart from this general issue this paper aims to raise awareness on a specific problem concerning divers life and training, namely on how the environment can affect their health. The clinical and statistical studies observed the incidence of pathological changes that occur in people exposed to hyperbaric environment, which more often than not can be the case of professional divers. What we also aim at is to find solutions for the elimination and avoidance of such risk factors

Keywords

  • hyperbaric environment
  • pathological changes
  • breathing gas mixture
  • water
Open Access

Theoretical and Practical Study on Divers’ Diet During Their Training Practice

Published Online: 22 Jul 2017
Page range: 103 - 113

Abstract

Abstract

The hereby paper briefly presents the specific objectives announced, the ways in which they have been carried out, the measures taken by the Divers Center, the divers’ awareness towards their duties, further measures to be taken, and finally the way all these are applied to divers’ everyday life. The paper concludes with interpretations, comments, final considerations on the research and development theme approached by the CPSA laboratory, along with future developments within the area of research

Keywords

  • diver’s feeding regime/diet
  • effort
  • weight index
  • improper nutrition
Open Access

Mobile Phone User Exposure Assessment to UMTS and LTE Signals at Mobile Data Turn on by Applying an Original Method

Published Online: 22 Jul 2017
Page range: 114 - 119

Abstract

Abstract

In order to provide assessment of mobile phone user exposure to electromagnetic fields emitted in the close vicinity of a mobile device we have measured real life UMTS and LTE signals at mobile data turn on. The paper presents some preliminary results of mobile phone user exposure assessment at mobile data turn by making use of a non-standardized procedure that enables the calculus of the radiated signal energy and duty cycle. Our results sustain that higher user exposure is expected within the first minute after mobile data is switched on as higher duty cycles and more than a third of the total radiated energy is found in this time period, as compared to the total signal monitoring time. Authors expect increased exposure if other application services are launched within this time frame. Moreover, special attention should be paid to user exposure assessment in the case of active call services with mobile data turned on. Because SAR is currently the sole standardized metrics in dosimetry, the authors propose the use of the measured signal radiated energy as well as the calculated duty cycle as complementary indicators of user exposure to electromagnetic fields in order to provide a more comprehensive view on mobile phone radiation exposure.

Keywords

  • exposure assessment
  • radiated power
  • mobile data turn on
  • UMTS
  • LTE
Open Access

Numerical Analyis of the Low-Altitude Air Turbulence Mathematical Models Used in Modelling of the Spatial Motion of the Small Unmanned Aerial Vehicles

Published Online: 22 Jul 2017
Page range: 120 - 130

Abstract

Abstract

Unmanned Aerial Vehicles designed and manufactured often with unknown origin but available in sale of the model aircraft market rarely deals with weather circumstances and conditions defining clearances for safe air operations of the UAV. UAVs used in low-altitude flight missions are often threatened by atmospheric turbulences leading either to high angle-of-attack (AoA) or leading to the stall of the UAV. There are many mathematical models well-known and widely applied in piloted aircraft aviation when to simulate atmospheric turbulences affecting spatial motion of the aircraft. This paper targets to evaluate and simulate numerically the low-altitude air turbulences, and, to examine the vertical gust speed of the small UAV. The UAV behaviour examined numerically will support to find weather clearances ensuring UAV flight safety having the level equal or higher to that level of manned aircraft regulated well-before. A computer code in MATLAB environment is created to support numerical analysis of the small UAV behaviour in low altitude atmospheric turbulence.

Keywords

  • air turbulence
  • modelling atmospheric turbulences
  • small UAV in turbulent air
  • numerical simulation
Open Access

Reducing the Phase-Noise In ΔΣ Fractional-N Synthezis – A Simulink Model

Published Online: 22 Jul 2017
Page range: 131 - 134

Abstract

Abstract

The resolution in fractional-N synthesis results as a fractional part of the reference frequency. This category of synthesizers permits a greater fref and a smaller N, a larger loop bandwidth, faster lock times and reduced output phase-noise. In ΔΣ fractional-N PLL’s the main problem is the specific quantization noise. To reduce them many techniques are used. The paper presents a Simulink model of the influence of the requantisation in the phase-noise cancellation process.

Keywords

  • frequency synthesis
  • ΔΣ modulator
  • phase-noise
Open Access

Computer Simulation - Efficient Tool of Crisis Management

Published Online: 22 Jul 2017
Page range: 135 - 141

Abstract

Abstract

The paper presents an analytical evaluation of the advantages of computer simulation of emergency situations within crisis management processes optimization. It affirms the efficiency of the preparation of crisis staffs, their coordination, communication and cooperation on the practical example of the SIMEX simulation tool.

Keywords

  • crisis management
  • communication
  • exercise
  • simulation
Open Access

Cargo Securing During Transportation – Using Extreme Values

Published Online: 22 Jul 2017
Page range: 142 - 147

Abstract

Abstract

This article analyses possibilities for securing cargo on selected military truck - middle cargo terrain Tatra T-810 DO AŠ. It presents a model of cargo securing using lashing straps, which is based on the minimum and maximum angle possible between lashing strap and horizontal plane where mounted. It compares inertial forces in the x-axis and y-axis, where the data source is in one case the basal variant of measured values of acceleration coefficients and in the second case normatively set values of acceleration coefficients. Both outputs - the size of the inertial forces in both axes are compared and a set of recommendations for cargo securing is formulated.

Keywords

  • transportation
  • cargo securing
  • acceleration coefficient
  • fastening strap
Open Access

Cargo Securing and Accident Rate in the Army of the Czech Republic

Published Online: 22 Jul 2017
Page range: 148 - 154

Abstract

Abstract

The article analyses the evolution of the accident rate in terms of the Army of the Czech Republic during last 6 years (2010-2015) and examines selected causes of vehicle accidents. In the context of the comparison of selected methods of cargo securing an analysis of potential risks in cargo securing on trucks of the Army of the Czech Republic has been done. A simple model of cargo securing on selected truck was created for these purposes. The model takes into account values measured in the field in comparison to conventional transport performed on highway and 2nd class road. Statistical analysis of the evaluation values of the coefficients of acceleration, which serves as a data source of the presented model, is included.

Keywords

  • transportation
  • cargo security
  • modelling
  • accident rate
Open Access

Unmanned Aerial Vehicle Influence of Troops Leading Procedure

Published Online: 22 Jul 2017
Page range: 155 - 162

Abstract

Abstract

Unmanned aerial vehicles, drones and other similar equipment are having a boom nowadays. Moreover, the usage of those modern technologies is also significant within armies. Unmanned aerial vehicles are extensively use within most of the military activities all over the world mainly on the battalion level and above. This paper is focused to discuss the usage of this technology on tactical level, particularly by squad and squad size units. The paper deals mainly with influence of unmanned aerial vehicles on troops leading procedure. The main methods of this paper are outcomes from the realized experiment. It shows on examples specific impact on all steps of the troops leading procedure. The experiment revealed interesting data and some possible conclusion were made. The primarily target of this paper is experience military personnel dealing with this topic. The paper should open broad discussion focused on all steps of troops leading procedure and outline the possible way of troops leading procedure update. Unmanned aerial vehicles, drones and other modern technology providing almost online information to the squad leader could significantly influence all steps of the troop leading procedure, safe preparation time as well as lives of the troops.

Keywords

  • unmanned aerial vehicle
  • troops leading procedure
  • small unit tactics
  • mission
  • squad
Open Access

Challenges for Sample Preparation and Analysis of New Matrices During the OPCW Proficiency Tests

Published Online: 22 Jul 2017
Page range: 163 - 167

Abstract

Abstract

In the OPCW Proficiency Tests usually two sets of three samples each (test sample, control, blank) are sent for analysis, with no indication for the type of the sample. Each set of samples can be prepared in a different matrix, with organic solvent, water and soil as the most frequent ones. Thus each sample has to be analyzed like a test sample. Participants are requested to identify any chemical contained in the schedules of the Chemical Weapons Convention plus all the degradation products that can originate from them; this involves millions of possible chemicals. Usually, a spiking level of ≈10 ppm is applied. Only chemicals that are considered relevant within the scenario of the proficiency test are to be reported. The choice of sample preparation method strongly depends on the composition of the sample and on the requirements for the different analytical techniques employed in the screening and analysis. Because the sample composition of proficiency test samples is unknown, no target compound sample preparation methods can be applied. New matrices, never used in a PT before, required participants to develop new or to adopt existing sample preparation methods. The new matrices from the 38th OPCW PT were linked to food, biodiesel like used cooking oil methyl ester and a 2% Agar-agar solution (solid gel). Aluminium metal and artificial rainwater chosen to provide matrix challenge for the 40th OPCW PT. The paper provides the challenges that are generated by the new and complex matrices, how to work up gel sample, the tendency of biodiesel to form emulsions, how to sub-sample “metal fragments”, and the method of extractions.

Keywords

  • OPCW
  • matrices
  • proficiency test
  • trichloronitromethane
  • 3-Quinuclidinyl benzilate
Open Access

The Influence of Temperature Changes on the Eigen - Frequencies and Mode Shapes for Rectangular Plates Clamped on the Contour

Published Online: 22 Jul 2017
Page range: 168 - 173

Abstract

Abstract

The alysis of free vibrations on rectangular plates with mixed conditions of buckling in the thermal environment is carried out by means of the 3D elasticity theory. In this paper there has been analyzed by the finite element method (FEM), the mode shape and the eigen-frequencies for a rectangular plate clamped on the contour for different temperatures. In this analysis successive heat degrees have been used, this fact helping to find the critical values in which the frequencies were at zero and to correlate these temperatures with the values obtained from the static analysis The temperature rise, the material graded index and the geometrical parameters on the eigen-frequencies were studied.

Keywords

  • temperature changes
  • eigen-frequencies
  • mode shapes
  • rectangular plates
  • FEM
Open Access

Numerical Modeling and Experimental Research of the Perforation Phenomenon of Certain Materials Used for Individual Protection by Bullets

Published Online: 22 Jul 2017
Page range: 174 - 179

Abstract

Abstract

The paper captures two aspects related to the phenomenon of impact between bullets and different types of materials used for the individual protection of the militaries, for the same type of ammunition and for the same configuration of the ballistic protection system, both in the case of the activity of experimental shooting range testing, as well as in the case of the modeling and simulation of the impact between the bullet and the protection materials.

Keywords

  • perforation
  • bullet
  • protection materials
  • armor
Open Access

Experimental Investigations on the Stress State in the Bearing Structure of a Special Wagon to Transport Liquid Iron

Published Online: 22 Jul 2017
Page range: 180 - 187

Abstract

Abstract

In order to increase productivity, to reduce energy consumption and for environmental protection, a special wagon intended for the transport of liquid pig iron, in steel mills, it was designed and manufactured. This wagon consists of an especial chamotted torpedo, with a capacity of 300 tons, rested, at each end, by means of a box beam, on two buggies, with four axles each one. To evaluate the mechanical behavior of this wagon during service, its prototype was investigated experimentally in terms of the stress and strain state. Due to difficulties encountered related to the long duration of loading and unloading time of the torpedo pot with liquid cast iron and due to very large dimensions of the carriage gauge, experimental investigations were performed on the torpedo pot and box beam models, manufactured at scale. The buggy structure was investigated on a special stand, set up in the laboratory of Strength of Materials Department of the Polytechnic University of Bucharest. The torpedo pot and box beam were investigated using two combined experimental techniques (brittle coatings technique and resistive strain gauge technique). Brittle coatings technique was used to identify the principal stresses directions, which then were applied electro-resistive transducers. Using strain gauge amplifiers the principal strains were measured, and principal stresses in measurement points were calculated. The results of these studies have led to changes of constructive solutions in the case of some substructures, contributing to increase the operational safety of the wagon.

Keywords

  • stress state
  • box beam
  • bogie
  • strain gauge
  • brittle coatings
Open Access

Design and Testing of an Unguided Rocket with Thermobaric Warhead for Multiple Launcher System

Published Online: 22 Jul 2017
Page range: 188 - 198

Abstract

Abstract

This paper presents the development, testing and evaluation of a new unguided rocket equipped with a thermobaric warhead. The aim of the research was to design the ammunition to be integrated with an existing multiple launch rocket system. This condition introduced limitations of dimensions, mass and mass distribution. The experimental work consisted also in optimisation of the thermobaric composition and configuration. The resulting ammunition was tested for determination of effective range and precision. The destructive effect was evaluated by live firing against non-armoured vehicles and masonry light structures.

Keywords

  • thermobaric
  • munitions
  • blast
  • energetic materials
Open Access

Numerical Modelling of Terminal Ballistic for 40 × 46 mm Lesslethal Kinetic Grenade

Published Online: 22 Jul 2017
Page range: 199 - 203

Abstract

Abstract

This paper presents the terminal ballistics of a 40×46mm less lethal grenade. The aim of the research was to determine the kinetic energy applied to the surface in the moment of impact and also the non-lethal characteristic of this ammunition. 40 × 46 mm less-lethal kinetic grenade is made of resilient material that increases its surface in the moment of impact in order to dissipate the kinetic energy developed

Keywords

  • 40×46 mm
  • less lethal
  • terminal ballistics
Open Access

Design and Performance Characteristics of New Female Bulletproof Vests

Published Online: 22 Jul 2017
Page range: 204 - 207

Abstract

Abstract

The new female bulletproof vest was designed with a superior female fit, this body armour providing a good balance between protection and comfort. One of the new issues in designing the female ballistic vest consists in taking into account the shape and bras size of Romanian female body, based on anthropometric survey using the 3D scanner technology. This bulletproof vest will provide comfort and mobility with the same or superior ballistic resistance properties versus standard body armour equipment. The ballistic performance parameters have been evaluated, in agreement with the international standards, in specialized laboratories of the Romanian MoD.

Keywords

  • female bulletproof
  • vest
  • body armour
Open Access

Maintenance System Research for Armored Vehicles in Peacekeeping Operation as Close Queueing System in Dynamic Regime

Published Online: 22 Jul 2017
Page range: 208 - 212

Abstract

Abstract

The maintenance system for wheel vehicles of 4th infantry battalion from Iraqi stable forces is studied in this article as a close queuing system. The differential equations of the dynamic functioning of the system are derived and solved numerically. The results of the dynamic characteristics and loading of the system are analyzed and compared with the results in stationary regime.

Keywords

  • Queuing model
  • maintenance
Open Access

Evacuation Algorithm of Armoured Vehicles

Published Online: 22 Jul 2017
Page range: 213 - 218

Abstract

Abstract

This publication analyses the main stages of evacuation of stuck and mind-bound armoured vehicles. A methodology and an algorithm have been developed for towing vehicles in cases of insufficient traction power of the traction engine.

Keywords

  • evacuation
  • armoured vehicles
Open Access

Virtual Model of the Terrain – A Reality Available to Everyone

Published Online: 22 Jul 2017
Page range: 219 - 223

Abstract

Abstract

Planning warfare at the tactical level, establishing and choosing the best course of action involves among other things, a precise knowledge of the configuration of the field in the area of engagement, disposition natural and artificial planimetric elements (layout) and their influence on warfare. Classical sandbox or sand table, tree branches, stones and other materials will be replaced with land simulation methods which located in the virtual sphere with minimal hardware and software investment and which will generate a report outstanding results with extremely high efficiency

Keywords

  • terrain
  • analysis
  • virtual
  • sandbox
Open Access

Resistance of Barrier Materials Against Toxic Compounds Permeation and Its Evaluation in Accordance with New European Norms

Published Online: 22 Jul 2017
Page range: 224 - 233

Abstract

Abstract

Study of barrier material resistance against permeation of toxic compounds belongs to a category of chemical warfare agents and toxic industrial chemicals are permanently insufficiently solved problems. This work deals with changes in approaches to testing barrier materials against toxic compounds permeation in static and dynamic conditions. An aim of this information is to describe specifications of cancelled norms of ČSN EN ISO 6529 (2002) a ČSN EN 374-3 (2004) with newly established norms ČSN EN 16523-1 a 16523-2 (2015). Authors focused on specification and comments of changes in such parts of norms concerning their scope, terms and definitions. A selected problem was solved with the help of analyse of newly established norms in a form of comments. Conditions for specification of understanding of mentioned problems in a context of established or occasionally prepared methods of testing resistance barrier materials against toxic compounds permeation have been formed with elaborated research.

Keywords

  • Protective clothing
  • barrier material
  • toxic compound
  • permeation
  • norm
Open Access

Chemical Resistance of Textile with a Butyl-Rubber Polymeric Mixture Against Decontamination Mixture on the Base of Chlorinated Aliphatic and Aromatic Hydrocarbons

Published Online: 22 Jul 2017
Page range: 234 - 242

Abstract

Abstract

Used equipment for providing hermetic isolative protection of the Czech Armed Forces Chemical Corps specialists’ body surface is currently solved with the employment of a mixture based on butyl-rubber. By producers declared protective properties of used barrier material does not mention a potential influence of decontamination mixtures and their components on the change of protective properties. A paper deals with selected chemical properties of butyl-rubber and points to the destructive influences of selected decontamination mixtures on protective textile used to production of isolative hermetic protective equipment. Study of barrier material chemical resistance against permeation of selected chemical compounds and mixtures creates the base presumption for evaluation of its usability.

Keywords

  • decontamination
  • decontamination mixture
  • breakthrough time
  • diffusion
Open Access

Experimental Research on the Manufactureof Parts Composing a Technical System Using Polymer Composite Materials

Published Online: 22 Jul 2017
Page range: 243 - 250

Abstract

Abstract

The article presents experimental research conducted by the authors for use of polymer composite materials to manufacture pressure parts of subassemblies composition of technical systems, currently manufactured from nonferrous materials. The research aimed to identify and establish a manufacturing technology specific for polymer composite materials and conducting testing and verification of resistance of manufactured parts, including their real operation conditions under pressure. The final part of the article highlights the authors’ conclusions, insisting on the advantages and disadvantages of the proposed method.

Keywords

  • polymer materials
  • FIBROPLAST BURNAS STI-20material
  • mechanical properties
Open Access

Selected Aspects of Vehicle Born Improvized Explosive Devices

Published Online: 22 Jul 2017
Page range: 251 - 256

Abstract

Abstract

The paper focuses on the analysis of the current highly dangerous tools of destruction, used mostly by insurgents and terrorists, especially in asymmetric warfare. Vehicles usually loaded with explosives (mostly homemade explosive), driven by suicide bombers are a significant threat to troops and the civilian population, not only in high risk areas. Analysis of the available incidents of this type, and available response to an incident mentioned in this article, it becomes the basic portfolio data for the design of effective elimination or at least reduction of the destructive effect, especially on soft targets.

Keywords

  • IED
  • VBIED
  • Tactics
  • Barrier
Open Access

Influence of the Shock Wave on the Hybrid Ballistic Gelatin

Published Online: 22 Jul 2017
Page range: 257 - 261

Abstract

Abstract

Forensic ballistic tests involve the use of various ballistic gelatins and soaps. Their use is restrained due to several important factors: their synthesis strategy, their availability at room temperature and their rapid degradation even when kept in cold places. The importance of human torso surrogates translates in the facility to verify various ballistic factors impact, such as shock wave or fragments. In the first case, the use of piezoelectric transducers and accelerometers inside torso surrogates helps in defining safety distances and materials for individual protection equipment.

Keywords

  • forensics
  • materials
  • ballistics
  • shock wave
Open Access

Methods For Determination of the Parameters of a Machine Gun Suspension Mounted on an Armoured Vehicle

Published Online: 22 Jul 2017
Page range: 262 - 267

Abstract

Abstract

The following report shows methods for determination of the coefficients of stiffness and damping, for softening the vibrations, which ensue in an armoured vehicle’s suspension from the shooting of a mounted machine-gun. The methods are based on a model of the movement smoothness, in which is additionally included the signal of the machine gun’s recoil.

Keywords

  • shooting
  • machine gun suspension
  • stiffness
  • damping

Plan your remote conference with Sciendo