AiMT Volume 12 (2017), Issue 1

Developments in the Classification of Aviation Accidents in Czechoslovak and Czech Military Aviation

O. Zavila

The article deals with the classification of emergency occurrences in Czechoslovak and Czech military aviation from 1946 to mid-2016. It lists available information sources and presents original definitions laid down therein, as well as many logical links and indications leading to the formulation of development trends in this field. The knowledge and proper understanding of the classification scales for emergency occurrences in both the Czechoslovak and the Czech military aviation in different periods is the key to understanding and correct interpretation of the statistics of aviation accidents and their preconditions. Statistics, the systematic mathematical processing of professional experience, is one of important bases for a positive development in any sector, which is also the case in military aviation.

Keywords: Army of the Czech Republic, Czechoslovak Army, Czechoslovak People’s Army, aviation accident, aviation occurrence, aviation emergency occurrence, development trend.

Pages: 5–20  [References]   [Download Citation]

Battery Voltage Limit Analysis with Support Vector Machine and Fuzzy Logic

R. Szabolcsi and J. Menyhárt

The efficiency and the range of modern electric vehicles are crucial points in their design. Designers and engineers are highly motivated to find solutions to these problems, or, as a rule, to improve existing electrical systems. Considerable number of modern batteries is available for use in electric vehicles and robots. The authors will propose new technology and new methods to use batteries with better efficiency. The authors propose to use the Support Vector Machine and Fuzzy logic in a new approach, which is the battery technical status management. The results show that it is possible to use these two methods simultaneously and they can ensure better results at the operation site.

Keywords: autonomous vehicle, UGV, SVM-Classification, fuzzy logic, battery.

Pages: 21–32  [References]   [Download Citation]

Current Capabilities of Modal Analysis of Aircraft Propeller in ANSYS Mechanical Environment

R. Vysoký

The article deals with the modal analysis of a small aircraft propeller. In here are discussed the possible three cases of the Finite Element Method (FEM) simulation, in the environment of ANSYS Mechanical software. Successively each of them is described by the theoretical and application parts. Further on, there are explained the important results from the modal analysis, i.e., the calculated natural frequencies, mode shapes, participation factors and effective masses. The following three cases of the FEM simulation were used: the classic approach, the cyclic symmetry modelling and the Component Mode Synthesis (CMS) method. At the end the calculated frequencies of the all three cases are compared.

Keywords: aircraft propeller, ANSYS, CMS, cyclic symmetry, dynamics, FEM, modal analysis.

Pages: 33–47  [References]   [Download Citation]

High Power LED Parametric Modelling Using a Double Polynomial Approximation

K. Zaplatílek and J. Leuchter

This article describes calculations for an accurate mathematical model of high power LED modules using double optimal polynomial approximation. The model is based on unique tests of various LED types in a thermal chamber, providing a comprehensive list of parametric temperature profiles. This model was then implemented into MATLAB®&Simulink® and Micro-Cap programs as a Spice compatible electronic circuit model, utilising the newly created algorithm. To define an optimal degree of approximation polynomials, Euclidean norm of residues was used. The new algorithm described in this article was verified using real-life data tested at the author’s work site, where the corresponding research takes place. To maximise the test’s efficiency, an automated data collection system was created. This article describes one particular tested LED module whose characteristic was modelled in both the absolute and the normalised form for easy comparison.

Keywords: high power LED module, optimal polynomial approximation, Euclidean norm of residues, MATLAB®&Simulink®, Spice compatible model, Micro-Cap simulator.

Pages: 49–60  [References]   [Download Citation]

Optimization of the Low-Speed Link Throughput for Voice Services

A. Mazálek, R. Bešťák, Z. Vránová and V. Plátěnka

The weak point of the field network is represented by E12 low-speed relay links. The situation requires savings of the bandwidth. For this purpose, the necessary bandwidth for voice transmission up to the level of the physical layer has been analyzed. As a suitable solution of network throughput increase, we propose the change of a Voice Payload Size. After finding the optimal Voice Payload Size, tests were carried out to verify the impact of the Voice Payload Size on call quality. A packet loss rate is chosen as a parameter for modelling real traffic. To obtain the expected voice quality, the E-model according to the G.107 Recommendation is applied. The theoretical results are compared with practical measurements, when using the proprietary Cisco Packet Loss Concealment algorithm to evaluate the voice quality. The results obtained have confirmed the suitability of the solution.

Keywords: packet loss, performance, voice payload size, VoIP.

Pages: 61–74  [References]   [Download Citation]

Knowledge Management Systems Based on Topic Maps Theory

L. Buřita, K. Halouzka, V. Malý and V. Ondryhal

The aim of the paper is to summarize the experience gained from the research and the constructions of the Knowledge Management Systems (KMS) based on the ontology engineering. Computational ontologies are the means to formally model the structure of a system, to discover the entities and relations that emerge from its observation, and which are useful to the system purposes. In our projects, we utilize the Topic Maps Theory and the tools based on this technology (e.g. ATOM2). The key point of the solution is the ontology development; our methodology procedure is presented; the improvement of the methodology and the future research goals are oriented to automate the procedure steps. During the process, the text mining tools (e.g. TOVEK) and other analytical tools are used. At the end of the paper, the summary of the experience with the methodology application is presented.

Keywords: knowledge management system, Topic Maps, ontology, ATOM, MENTAL, CEFME.

Pages: 75–89  [References]   [Download Citation]

Substantiation of Reliability Requirements for Mobility Means of Surface-to-Air Missile Systems

P.V. Open’ko, P.A. Drannyk, V.V. Kobzev, M.B. Brovko and G.S. Zalevsky

Common principles of substantiation of reliability requirements for vehicles (mobility means) of surface-to-air missile (SAM) systems are discussed. The principles mentioned include the impact of a hierarchically-branched structure of SAM system and reliability of their vehicles on system effectiveness under the real conditions. As the complex measure of SAM system effectiveness the coefficient of effectiveness sustainment of SAM system combat (technical) mobility means is used, which is the ratio of system output effect characteristic taking into account reliability measures of mobility means to its value in case, when mobility means do not have failures. The coefficient used here is considered to be the function of mean distance between failures (MDBF) of mobility means and their number.

Keywords: effectiveness of the hierarchic system, mobility means, reliability requirements, surface-to-air missile system.

Pages: 91–99  [References]   [Download Citation]

Modelling and Comparison of Tracking Loops for GPS Signal

B.N. Vu and M. Andrle

Nowadays, Global Positioning System (GPS) applications are widely spread and affect all aspects of our modern lives. They can be found in many different fields, such as aviation, environment, marine, space, surveying, mapping, and military operations. In military, the GPS is employed in missile guidance, vessels and aircraft navigation, location, communication network timing, etc. The GPS receiver is required to be more and more robust to withstand harsh condition, for example losing signal or jamming. This paper demonstrates the implementation and simulation of an advanced tracking technique that is used in modern GPS receivers – a vector tracking loop. Brief related principles of a GPS receiver are introduced. The principle of traditional tracking loop is shown and compared to the vector tracking loop. An extended Kalman filter is employed as a vector tracking algorithm. The extended Kalman filter uses pseudo range rate, which is computed from both the code and the carrier to constrain the receiver velocity. The acquired results are compared and advantages of the vector tracking algorithm against the traditional tracking loop are presented in this paper, including characteristics of the vector tracking loop.

Keywords: vector tracking loop, Kalman filter.

Pages: 101–112  [References]   [Download Citation]

Assessment of Selected Cannons according to the Probability of Target Destruction

J. Němeček and M. Polášek

The article discribes combat effectiveness of aircraft automatic cannons and compares combat effectiveness of M61A1 rotary cannon with cannons being used on aircraft of the Czech Air Force. The procedure and examples of probability calculation for aerial target destruction are presented for hight rate of fire weapons firing one burst. The procedure is shown for a step law and an exponential law of target destruction and for the constant and changing target hit probability. Basic characteristics for all types of rapid-firing cannons which are part of standard armament of modern aircraft are included in this paper.

Keywords: aircraft automatic cannon, rate of fire, probability of target hits, law of destruction.

Pages: 113–128  [References]   [Download Citation]

Probabilistic Gross Vehicle Weights and Associated Axle Loads for Military Vehicles in Bridge Evaluation and Code Calibration

A.J. MacDonald, F.M. Bartlett, and R. Gordon Wight

Military vehicles frequently use civilian bridges. The loading effects of military vehicles, both wheeled and tracked, are specific and different than those of civilian vehicles in normal traffic. Calibration to determine appropriate load factors for military loading of civilian bridges has not been fully performed and the corresponding levels of safety have not been quantified. This is partially due to the lack of probabilistic information of the gross vehicle weights and corresponding axle loads of military vehicles while operating in real-world conditions. This paper quantifies probabilistically the gross vehicle weight and axle loads for three military vehicles in use by NATO, each of which is representative of: military transport vehicles; armoured personnel carriers; and main battle tanks. A general means are proposed to quantify the probabilistic gross vehicle weight of military vehicles on the basis of maximum nominal payload as a proportion of the total nominal vehicle weight. Based on observed probabilistic gross vehicle weight of military vehicles, it is recommended to differentiate between military transport and military fighting vehicles as different categories of vehicles in bridge evaluation.

Keywords: highway bridge design, highway bridge evaluation, military vehicle, gross vehicle weight, military engineering.

Pages: 129–145  [References]   [Download Citation]

Using Aviation Simulation Technologies for Pilot Modelling and Flight Training Assessment

J. Boril, M. Jirgl and R. Jalovecky

This paper summarises many years of the results of the development and modelling of human behaviour while flying an aircraft, from a flight automation point of view. The introduction presents the challenges of describing and modelling human behaviour. Based on that knowledge, options for acquiring parameters for a pilot behaviour model are described. Then, analysis of pilot response is presented, acquired from many tests on two simulators (stationary and motion-platform). These experimental tests are pilot responses to a visual stimulus and also partially to motion stimulus – step change in flight altitude where the task of the pilot is to return the flight, as quickly as possible to the original flight altitude. Due to the vast amount of test data files – missions from each test – the authors rewrote the identification algorithms for batch data processing and utilised a Salamon supercomputer located at Technical University of Ostrava. In the first phase of implementation of the identification algorithms, the calculations were 4 times faster, and after rewriting the algorithms for parallel calculations, the authors expect the speed to increase more than 10 times.

Keywords: flight simulators, simulation technologies, pilot training, pilot modelling, human behaviour model, MATLAB®.

Pages: 147–161  [References]   [Download Citation]

Professor Lubomír Popelínský, 85, died

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Impressions from the ICMT’17

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New Trends in Signal Processing 2018

Call for Papers