Abstract: Responses of the dynamical systems are highly affected by the natural frequencies and it has a huge impact on design and operation of high-rise and high-speed elevators. In the present paper, the variational iteration method (VIM) is employed to investigate better understanding the dynamics of elevator cable as a single-degree-of-freedom (SDOF) swing system. Comparisons made among the results of the proposed closed-form analytical solution, the traditional numerical iterative time integration solution, and the linearized governing equations confirm the accuracy and efficiency of the proposed approach. Furthermore, based on the results of the proposed closed-form solution, the linearization errors in calculating the natural frequencies in different cases are discussed.
Abstract: A preliminary evaluation of the urban land system is
presented in the article together with the instruments of land policy in
Serbia. The main reason for the analysis is demand for
definition of reform framework for urban land management in
Serbia in the period of transition towards market-led system. It
is concluded that due to the limitations of the current regulation it
will be impossible in the future to apply market principles in the
urban land policy (supply and demand of land, land capitalization,
investment efficiency, et al.). Based on the estimation that the urban
land system and land policy are key factors of competitiveness
between regions and towns in Serbia, it is necessary to initiate
changes in this field. There are indicated on an option of privatization
of urban public land and possible establishment of leasehold land. A
comparative analysis of the possibilities of the reform urban land
system in Serbia has been carried out in relation to two approaches of
market systems: (a) with dominant private ownership of urban land
(neo/liberal approach) and (b) with dominant public ownership of
urban land (system of leasehold)whose findings can be a basis for
further study of the new system in Serbia.. The attanied results are
part of studies matter for the making of Strategy of territorial
development of Serbia.
Abstract: The commercial finite element program LS-DYNA was employed to evaluate the response and energy absorbing capacity of cylindrical metal tubes that are externally wrapped with composite. The effects of composite wall thickness, loading conditions and fiber ply orientation were examined. The results demonstrate that a wrapped composite can be utilized effectively to enhance the crushing characteristics and energy absorbing capacity of the tubes. Increasing the thickness of the composite increases the mean force and the specific energy absorption under both static and dynamic crushing. The ply pattern affects the energy absorption capacity and the failure mode of the metal tube and the composite material property is also significant in determining energy absorption efficiency.
Abstract: With the development of technology, the growing
trend of fast and safe passenger transport, air pollution, traffic
congestion, increase in problems such as the increasing population
and the high cost of private vehicle usage made many cities around
the world with a population of more or less, start to build rail systems
as a means of urban transport in order to ensure the economic and
environmental sustainability and more efficient use of land in the
city. The implementation phase of rail systems costs much more than
other public transport systems. However, social and economic returns
in the long term made these systems the most popular investment tool
for planned and developing cities.
In our country, the purpose, goals and policies of transportation
plans are away from integrity, and the problems are not clearly
detected. Also, not defined and incomplete assessment of
transportation systems and insufficient financial analysis are the most
important cause of failure. Rail systems and other transportation
systems to be addressed as a whole is seen as the main factor in
increasing efficiency in applications that are not integrated yet in our
country to come to this point has led to the problem.
Abstract: A stiffened laminated composite panel (1 m length ×
0.5m width) was optimized for minimum weight and deflection under
several constraints using genetic algorithm. Here, a significant study
on the performance of a penalty function with two kinds of static and
dynamic penalty factors was conducted. The results have shown that
linear dynamic penalty factors are more effective than the static ones.
Also, a specially combined linear-exponential function has shown to
perform more effective than the previously mentioned penalty
functions. This was then resulted in the less sensitivity of the GA to
the amount of penalty factor.
Abstract: This presentation reviews recent advances in superalloys and thermal barrier coating (TBC) for application in hot sections of energy-efficient gas-turbine engines. It has been reviewed that in the modern combined-cycle gas turbines (CCGT) applying single-crystal energy materials (SC superalloys) and thermal barrier coatings (TBC), and – in one design – closed-loop steam cooling, thermal efficiency can reach more than 60%. These technological advancements contribute to profitable and clean power generation with reduced emission. Alternatively, the use of advanced superalloys (e.g. GTD-111 superalloy, Allvac 718Plus superalloy) and advanced thermal barrier coatings (TBC) in modern gas-turbines has been shown to yield higher energy-efficiency in power generation.
Abstract: This research paper presents a framework on how to
build up malware dataset.Many researchers took longer time to
clean the dataset from any noise or to transform the dataset into a
format that can be used straight away for testing. Therefore, this
research is proposing a framework to help researchers to speed up
the malware dataset cleaningprocesses which later can be used for
testing. It is believed, an efficient malware dataset cleaning
processes, can improved the quality of the data, thus help to improve
the accuracy and the efficiency of the subsequent analysis. Apart
from that, an in-depth understanding of the malware taxonomy is
also important prior and during the dataset cleaning processes. A
new Trojan classification has been proposed to complement this
framework.This experiment has been conducted in a controlled lab
environment and using the dataset from VxHeavens dataset. This
framework is built based on the integration of static and dynamic
analyses, incident response method and knowledge database
discovery (KDD) processes.This framework can be used as the basis
guideline for malware researchers in building malware dataset.
Abstract: This paper presents a numerical investigation of the
unsteady flow around an American 19th century vertical-axis
windmill: the Stevens & Jolly rotor, patented on April 16, 1895. The
computational approach used is based on solving the complete
transient Reynolds-Averaged Navier-Stokes (t-RANS) equations: a
full campaign of numerical simulation has been performed using the
k-ω SST turbulence model. Flow field characteristics have been
investigated for several values of tip speed ratio and for a constant
unperturbed free-stream wind velocity of 6 m/s, enabling the study of
some unsteady flow phenomena in the rotor wake. Finally, the global
power generated from the windmill has been determined for each
simulated angular velocity, allowing the calculation of the rotor
power-curve.
Abstract: This paper presents the H-ARQ techniques comparison for OFDM systems with a new family of non-binary LDPC codes which has been developed within the EU FP7 DAVINCI project. The punctured NB-LDPC codes have been used in a simulated model of the transmission system. The link level performance has been evaluated in terms of spectral efficiency, codeword error rate and average number of retransmissions. The NB-LDPC codes can be easily and effective implemented with different methods of the retransmission needed if correct decoding of a codeword failed. Here the Optimal Symbol Selection method is proposed as a Chase Combining technique.
Abstract: Anaerobic Digestion has become a promising
technology for biological transformation of organic fraction of the
municipal solid wastes (MSW). In order to represent the kinetic
behavior of such biological process and thereby to design a reactor
system, development of a mathematical model is essential.
Addressing this issue, a simplistic mathematical model has been
developed for anaerobic digestion of MSW in a continuous flow
reactor unit under homogeneous steady state condition. Upon
simulated hydrolysis, the kinetics of biomass growth and substrate
utilization rate are assumed to follow first order reaction kinetics.
Simulation of this model has been conducted by studying sensitivity
of various process variables. The model was simulated using typical
kinetic data of anaerobic digestion MSW and typical MSW
characteristics of Kolkata. The hydraulic retention time (HRT) and
solid retention time (SRT) time were mainly estimated by varying
different model parameters like efficiency of reactor, influent
substrate concentration and biomass concentration. Consequently,
design table and charts have also been prepared for ready use in the
actual plant operation.
Abstract: The reluctance motor is an electric motor in which
torque is produced by the tendency of its moveable part to move to a
position where the inductance of the excited winding is maximized.
In this paper switched reluctance motors (SRMs) with two different
configurations(3-phase SRM with 4rotor poles and 6 stator poles, 4-
phase SRM with 6rotor poles and 8 stator poles) is designed by
RMxprt, and performance of them is analyzed. Efficiency and torque
of SRM for different configurations in full-load condition have been
presented. The results indicate that with correct choosing of motor
applications, maximum efficiency can be found.
Abstract: Space Vector Pulse Width Modulation SVPWM is
one of the most used techniques to generate sinusoidal voltage and
current due to its facility and efficiency with low harmonics
distortion. This algorithm is specially used in power electronic
applications. This paper describes simulation algorithm of SVPWM
& SPWM using MatLab/simulink environment. It also implements a
closed loop three phases DC-AC converter controlling its outputs
voltages amplitude and frequency using MatLab. Also comparison
between SVPWM & SPWM results is given.
Abstract: This paper presents a vocoder to obtain high quality synthetic speech at 600 bps. To reduce the bit rate, the algorithm is based on a sinusoidally excited linear prediction model which extracts few coding parameters, and three consecutive frames are grouped into a superframe and jointly vector quantization is used to obtain high coding efficiency. The inter-frame redundancy is exploited with distinct quantization schemes for different unvoiced/voiced frame combinations in the superframe. Experimental results show that the quality of the proposed coder is better than that of 2.4kbps LPC10e and achieves approximately the same as that of 2.4kbps MELP and with high robustness.
Abstract: The objective of this paper is to present a research
study of the convectors that are used for heating or cooling of the
living room or industrial halls. The key points are experimental
measurement and comprehensive numerical simulation of the flow
coming throughout the part of the convector such as heat exchanger,
input from the fan etc.. From the obtained results, the components of
the convector are optimized in sense to increase thermal power
efficiency due to improvement of heat convection or reduction of air
drag friction. Both optimized aspects are leading to the more
effective service conditions and to energy saving. The significant part
of the convector research is a design of the unique measurement
laboratory and adopting measure techniques. The new laboratory
provides possibility to measure thermal power efficiency and other
relevant parameters under specific service conditions of the
convectors.
Abstract: POS (also been called DGPS/IMU) technique can obtain the Exterior Orientation Elements of aerial photo, so the triangulation and DLG production using POS can save large numbers of ground control points (GCP), and this will improve the produce efficiency of DLG and reduce the cost of collecting GCP. This paper mainly research on POS technique in production of 1:10 000 scale DLG on GCP distribution. We designed 23 kinds of ground control points distribution schemes, using integrated sensor direction method to do the triangulation experiments, based on the results of triangulation, we produce a map with the scale of 1:10 000 and test its accuracy. This paper put forward appropriate GCP distributing schemes by experiments and research above, and made preparations for the application of POS technique on photogrammetry 4D data production.
Abstract: Today global warming, climate change and energy supply are of greater concern as it is widely realized that the planet earth does not provide an infinite capacity for absorbing human industrialization in the 21st century. The aim of this paper is to analyze upstream and downstream electricity production in selected case studies: a coal power plant, a pump system and a microwave oven covering and consumption to explore the position of energy efficiency in engineering sustainability. Collectively, the analysis presents energy efficiency as a major pathway towards sustainability that requires an inclusive and a holistic supply chain response in the engineering design process.
Abstract: In the competitive environment of aircraft industries it becomes absolutely necessary to improve the efficiency, performance of the aircrafts to reduce the development and operating costs considerably, in order to capitalize the market. An important contribution to improve the efficiency and performance can be
achieved by decreasing the aircraft weight through considerable
usage of composite materials in primary aircraft structures. In this study, a type of composite material called Carbon Fiber Reinforced
Plastic (CFRP) is explored for the usage is aircraft skin panels. Even
though there were plenty of studies and research has been already
carried out, here a practical example of an aircraft skin panel is taken
and substantiated the benefits of composites material usage over the
metallic skin panel. A crown skin panel of a commercial aircraft is
designed using both metal and composite materials. Stress analysis
has been carried out for both and margin of safety is estimated for the
critical load cases. The skin panels are compared for manufacturing,
tooling, assembly and cost parameters. Detail step by step comparison between metal and composite constructions are studied
and results are tabulated for better understanding.
Abstract: In recent years, we see an increase of interest for efficient tracking systems in surveillance applications. Many of the proposed techniques are designed for static cameras environments. When the camera is moving, tracking moving objects become more difficult and many techniques fail to detect and track the desired targets. The problem becomes more complex when we want to track a specific object in real-time using a moving Pan and Tilt camera system to keep the target within the image. This type of tracking is of high importance in surveillance applications. When a target is detected at a certain zone, the possibility of automatically tracking it continuously and keeping it within the image until action is taken is very important for security personnel working in very sensitive sites. This work presents a real-time tracking system permitting the detection and continuous tracking of targets using a Pan and Tilt camera platform. A novel and efficient approach for dealing with occlusions is presented. Also a new intelligent forget factor is introduced in order to take into account target shape variations and avoid learning non desired objects. Tests conducted in outdoor operational scenarios show the efficiency and robustness of the proposed approach.
Abstract: Multimedia courseware has been accepted as a tool
that can support teaching and learning process. 'Li2D' courseware
was developed to assist student-s visualization on the topic of Loci in
Two Dimension. This paper describes an evaluation on the
effectiveness and usability of a 'Li2D' courseware. The quasi
experiment was used for the effectiveness evaluation. Usability
evaluation was accomplished based on four constructs of usability,
namely: efficiency, learnability, screen design and satisfaction. An
evaluation on the multimedia elements was also conducted. A total of
63 students of Form Two are involved in the study. The students are
divided into two groups: control and experimental. The experimental
group had to interact with 'Li2D' courseware as part of the learning
activities while the control group used the conventional learning
methods. The results indicate that the experimental group performed
better than the control group in understanding the Loci in Two
Dimensions topic. In terms of usability, the results showed that the
students agreed on the usability in multimedia elements in the 'Li2D'
courseware.
Abstract: The process for predicting the ballistic properties of a liquid rocket engine is based on the quantitative estimation of idealized performance deviations. In this aim, an equilibrium chemistry procedure is firstly developed and implemented in a Fortran routine. The thermodynamic formulation allows for the calculation of the theoretical performances of a rocket thrust chamber. In a second step, a computational fluid dynamic analysis of the turbulent reactive flow within the chamber is performed using a finite volume approach. The obtained values for the “quasi-real" performances account for both turbulent mixing and chemistryturbulence coupling. In the present work, emphasis is made on the combustion efficiency performance for which deviation is mainly due to radial gradients of static temperature and mixture ratio. Numerical values of the characteristic velocity are successfully compared with results from an industry-used code. The results are also confronted with the experimental data of a laboratory-scale rocket engine.