Abstract: This paper presents a computational study of steady
state three dimensional very high turbulent flow and heat transfer
characteristics in a constant temperature-surfaced circular duct fitted
with 900 hemispherical inline baffles. The computations are based on
realizable k-ɛ model with standard wall function considering the
finite volume method, and the SIMPLE algorithm has been
implemented. Computational Study are carried out for Reynolds
number, Re ranging from 80000 to 120000, Prandtl Number, Pr of
0.73, Pitch Ratios, PR of 1,2,3,4,5 based on the hydraulic diameter of
the channel, hydrodynamic entry length, thermal entry length and the
test section. Ansys Fluent 15.0 software has been used to solve the
flow field. Study reveals that circular pipe having baffles has a higher
Nusselt number and friction factor compared to the smooth circular
pipe without baffles. Maximum Nusselt number and friction factor
are obtained for the PR=5 and PR=1 respectively. Nusselt number
increases while pitch ratio increases in the range of study; however,
friction factor also decreases up to PR 3 and after which it becomes
almost constant up to PR 5. Thermal enhancement factor increases
with increasing pitch ratio but with slightly decreasing Reynolds
number in the range of study and becomes almost constant at higher
Reynolds number. The computational results reveal that optimum
thermal enhancement factor of 900 inline hemispherical baffle is
about 1.23 for pitch ratio 5 at Reynolds number 120000.It also shows
that the optimum pitch ratio for which the baffles can be installed in
such very high turbulent flows should be 5. Results show that pitch
ratio and Reynolds number play an important role on both fluid flow
and heat transfer characteristics.
Abstract: Experts, enterprises and operators expect that the
bandwidth request will increase up to rates of 100 to 1,000 Mbps
within several years. Therefore the most important question is which
technology shall satisfy the future consumer broadband demands.
Currently the consensus is, that the fiber technology has the best
technical characteristics to achieve such the high bandwidth rates.
But fiber technology is so far very cost-intensive and resource
consuming. To avoid these investments, operators are concentrating
to upgrade the existing copper and hybrid fiber coax infrastructures.
This work presents a comparison of the copper and fiber
technologies including an overview about the current German
broadband market. Both technologies are reviewed in the terms of
demand, willingness to pay and economic efficiency in connection
with the technical characteristics.
Abstract: The aim of this investigation is to elaborate nearinfrared
methods for testing and recognition of chemical components
and quality in “Pannon wheat” allied (i.e. true to variety or variety
identified) milling fractions as well as to develop spectroscopic
methods following the milling processes and evaluate the stability of
the milling technology by different types of milling products and
according to sampling times, respectively. These wheat categories
produced under industrial conditions where samples were collected
versus sampling time and maximum or minimum yields. The changes
of the main chemical components (such as starch, protein, lipid) and
physical properties of fractions (particle size) were analysed by
dispersive spectrophotometers using visible (VIS) and near-infrared
(NIR) regions of the electromagnetic radiation. Close correlation
were obtained between the data of spectroscopic measurement
techniques processed by various chemometric methods (e.g. principal
component analysis [PCA], cluster analysis [CA]) and operation
condition of milling technology. It is obvious that NIR methods are
able to detect the deviation of the yield parameters and differences of
the sampling times by a wide variety of fractions, respectively. NIR
technology can be used in the sensitive monitoring of milling
technology.
Abstract: By the evolvement in technology, the way of
expressing opinions switched direction to the digital world. The
domain of politics, as one of the hottest topics of opinion mining
research, merged together with the behavior analysis for affiliation
determination in texts, which constitutes the subject of this paper.
This study aims to classify the text in news/blogs either as
Republican or Democrat with the minimum number of features. As
an initial set, 68 features which 64 were constituted by Linguistic
Inquiry and Word Count (LIWC) features were tested against 14
benchmark classification algorithms. In the later experiments, the
dimensions of the feature vector reduced based on the 7 feature
selection algorithms. The results show that the “Decision Tree”,
“Rule Induction” and “M5 Rule” classifiers when used with “SVM”
and “IGR” feature selection algorithms performed the best up to
82.5% accuracy on a given dataset. Further tests on a single feature
and the linguistic based feature sets showed the similar results. The
feature “Function”, as an aggregate feature of the linguistic category,
was found as the most differentiating feature among the 68 features
with the accuracy of 81% in classifying articles either as Republican
or Democrat.
Abstract: Any signal transmitted over a channel is corrupted by noise and interference. A host of channel coding techniques has been proposed to alleviate the effect of such noise and interference. Among these Turbo codes are recommended, because of increased capacity at higher transmission rates and superior performance over convolutional codes. The multimedia elements which are associated with ample amount of data are best protected by Turbo codes. Turbo decoder employs Maximum A-posteriori Probability (MAP) and Soft Output Viterbi Decoding (SOVA) algorithms. Conventional Turbo coded systems employ Equal Error Protection (EEP) in which the protection of all the data in an information message is uniform. Some applications involve Unequal Error Protection (UEP) in which the level of protection is higher for important information bits than that of other bits. In this work, enhancement to the traditional Log MAP decoding algorithm is being done by using optimized scaling factors for both the decoders. The error correcting performance in presence of UEP in Additive White Gaussian Noise channel (AWGN) and Rayleigh fading are analyzed for the transmission of image with Discrete Cosine Transform (DCT) as source coding technique. This paper compares the performance of log MAP, Modified log MAP (MlogMAP) and Enhanced log MAP (ElogMAP) algorithms used for image transmission. The MlogMAP algorithm is found to be best for lower Eb/N0 values but for higher Eb/N0 ElogMAP performs better with optimized scaling factors. The performance comparison of AWGN with fading channel indicates the robustness of the proposed algorithm. According to the performance of three different message classes, class3 would be more protected than other two classes. From the performance analysis, it is observed that ElogMAP algorithm with UEP is best for transmission of an image compared to Log MAP and MlogMAP decoding algorithms.
Abstract: The main function of Medium Access Control (MAC) is to share the channel efficiently between all nodes. In the real-time scenario, there will be certain amount of wastage in bandwidth due to back-off periods. More bandwidth will be wasted in idle state if the back-off period is very high and collision may occur if the back-off period is small. So, an optimization is needed for this problem. The main objective of the work is to reduce delay due to back-off period thereby reducing collision and increasing throughput. Here a method, called the virtual back-off algorithm (VBA) is used to optimize the back-off period and thereby it increases throughput and reduces collisions. The main idea is to optimize the number of transmission for every node. A counter is introduced at each node to implement this idea. Here counter value represents the sequence number. VBA is classified into two types VBA with counter sharing (VBA-CS) and VBA with no counter sharing (VBA-NCS). These two classifications of VBA are compared for various parameters. Simulation is done in NS-2 environment. The results obtained are found to be promising.
Abstract: The venture capital becomes more and more advanced
and effective source of the innovation project financing, connected
with a high-risk level. In the developed countries, it plays a key role
in transforming innovation projects into successful businesses and
creating the prosperity of the modern economy. In Russia, there are
many necessary preconditions for creation of the effective venture
investment system: the network of the public institutes for innovation
financing operates; there is a significant number of the small and
medium-sized enterprises, capable to sell production with good
market potential. However, the current system does not confirm the
necessary level of efficiency in practice that can be substantially
explained by the absence of the accurate plan of action to form the
national venture model and by the lack of experience of successful
venture deals with profitable exits in Russian economy. This paper
studies the influence of various factors on the venture industry
development by the example of the IT-sector in Russia. The choice of
the sector is based on the fact, that this segment is the main driver of
the venture capital market growth in Russia, and the necessary set of
data exists. The size of investment of the second round is used as the
dependent variable. To analyse the influence of the previous round,
such determinant as the volume of the previous (first) round
investments is used. There is also used a dummy variable in
regression to examine that the participation of an investor with high
reputation and experience in the previous round can influence the size
of the next investment round. The regression analysis of short-term
interrelations between studied variables reveals prevailing influence
of the volume of the first round investments on the venture
investments volume of the second round. The most important
determinant of the value of the second-round investment is the value
of first–round investment, so it means that the most competitive on
the Russian market are the start-up teams that can attract more money
on the start, and the target market growth is not the factor of crucial
importance. This supports the point of view that VC in Russia is
driven by endogenous factors and not by exogenous ones that are
based on global market growth.
Abstract: Electrohydraulic servo system have been used in industry in a wide number of applications. Its dynamics are highly nonlinear and also have large extent of model uncertainties and external disturbances. In this paper, a robust back-stepping control (RBSC) scheme is proposed to overcome the problem of disturbances and system uncertainties effectively and to improve the tracking performance of EHS systems. In order to implement the proposed control scheme, the system uncertainties in EHS systems are considered as total leakage coefficient and effective oil volume. In addition, in order to obtain the virtual controls for stabilizing system, the update rule for the system uncertainty term is induced by the Lyapunov control function (LCF). To verify the performance and robustness of the proposed control system, computer simulation of the proposed control system using Matlab/Simulink Software is executed. From the computer simulation, it was found that the RBSC system produces the desired tracking performance and has robustness to the disturbances and system uncertainties of EHS systems.
Abstract: Biodiesel as an alternative diesel fuel is steadily gaining more attention and significance. However, there are some drawbacks while using biodiesel regarding its properties that requires it to be blended with petrol based diesel and/or additives to improve the fuel characteristics. This study analyses thermal cracking as an alternative technology to improve biodiesel characteristics in which, FAME based biodiesel produced by transesterification of castor oil is fed into a continuous thermal cracking reactor at temperatures range of 450-500°C and flowrate range of 20-40 g/hr. Experiments designed by response surface methodology and subsequent statistical studies show that temperature and feed flowrate significantly affect the products yield. Response surfaces were used to study the impact of temperature and flowrate on the product properties. After each experiment, the produced crude bio-oil was distilled and diesel cut was separated. As shorter chain molecules are produced through thermal cracking, the distillation curve of the diesel cut fitted more with petrol based diesel curve in comparison to the biodiesel. Moreover, the produced diesel cut properties adequately pose within property ranges defined by the related standard of petrol based diesel. Cold flow properties, high heating value as the main drawbacks of the biodiesel are improved by this technology. Thermal cracking decreases kinematic viscosity, Flash point and cetane number.
Abstract: The present study is concerned with the problem of determining the shape of the free surface flow in a hydraulic channel which has an uneven bottom. For the mathematical formulation of the problem, the fluid of the two-dimensional irrotational steady flow in water is assumed inviscid and incompressible. The solutions of the nonlinear problem are obtained by using the usual conformal mapping theory and Hilbert’s technique. An experimental study, for comparing the obtained results, has been conducted in a hydraulic channel (subcritical regime and supercritical regime).
Abstract: To solve these problems, we investigated the management system of heating enterprise, including strategic planning based on the balanced scorecard (BSC), quality management in accordance with the standards of the Quality Management System (QMS) ISO 9001 and analysis of the system based on expert judgment using fuzzy inference. To carry out our work we used the theory of fuzzy sets, the QMS in accordance with ISO 9001, BSC, method of construction of business processes according to the notation IDEF0, theory of modeling using Matlab software simulation tools and graphical programming LabVIEW. The results of the work are as follows: We determined possibilities of improving the management of heat-supply plant-based on QMS; after the justification and adaptation of software tool it has been used to automate a series of functions for the management and reduction of resources and for the maintenance of the system up to date; an application for the analysis of the QMS based on fuzzy inference has been created with novel organization of communication software with the application enabling the analysis of relevant data of enterprise management system.
Abstract: Based on an indoor environmental quality (IEQ) index established by previous work that indicates the overall IEQ acceptance from the prospect of an occupant in residential buildings in terms of four IEQ factors - thermal comfort, indoor air quality, visual and aural comforts, this study develops a user-friendly IEQ calculator for iOS and Android users to calculate the occupant acceptance and compare the relative performance of IEQ in apartments. “IEQ calculator” is easy to use and it preliminarily illustrates the overall indoor environmental quality on the spot. Users simply input indoor parameters such as temperature, number of people and windows are opened or closed for the mobile application to calculate the scores in four areas: the comforts of temperature, brightness, noise and indoor air quality. The calculator allows the prediction of the best IEQ scenario on a quantitative scale. Any indoor environments under the specific IEQ conditions can be benchmarked against the predicted IEQ acceptance range. This calculator can also suggest how to achieve the best IEQ acceptance among a group of residents.
Abstract: Rapidly changing factors that affect daily life also affect operational environment and the way military leaders fulfill their missions. With the help of technological developments, traditional linearity of conflict and war has started to fade away. Furthermore, mission domain has broadened to include traditional threats, hybrid threats and new challenges of cyber and space. Considering the future operational environment, future military leaders need to adapt themselves to the new challenges of the future battlefield. But how to decide what kind of features of leadership are required to operate and accomplish mission in the new complex battlefield? In this article, the main aim is to provide answers to this question. To be able to find right answers, first leadership and leadership components are defined, and then characteristics of future operational environment are analyzed. Finally, leadership features that are required to be successful in redefined battlefield are explained.
Abstract: Surf is an increasingly popular sport and its performance evaluation is often qualitative. This work aims at using a smartphone to collect and analyze the GPS and inertial sensors data in order to obtain quantitative metrics of the surfing performance. Two approaches are compared for detection of wave rides, computing the number of waves rode in a surfing session, the starting time of each wave and its duration. The first approach is based on computing the velocity from the Global Positioning System (GPS) signal and finding the velocity thresholds that allow identifying the start and end of each wave ride. The second approach adds information from the Inertial Measurement Unit (IMU) of the smartphone, to the velocity thresholds obtained from the GPS unit, to determine the start and end of each wave ride. The two methods were evaluated using GPS and IMU data from two surfing sessions and validated with similar metrics extracted from video data collected from the beach. The second method, combining GPS and IMU data, was found to be more accurate in determining the number of waves, start time and duration. This paper shows that it is feasible to use smartphones for quantification of performance metrics during surfing. In particular, detection of the waves rode and their duration can be accurately determined using the smartphone GPS and IMU.
Abstract: Security can be defined as the degree of resistance to, or protection from harm. It applies to any vulnerable and valuable assets, such as persons, dwellings, communities, nations or organizations. Cybercrime is any crime committed or facilitated via the Internet. It is any criminal activity involving computers and networks. It can range from fraud to unsolicited emails (spam). It includes the distant theft of government or corporate secrets through criminal trespass into remote systems around the globe. Nigeria like any other nations of the world is currently having her own share of the menace that has been used even as tools by terrorists. This paper is an attempt at presenting cyber security as an issue that requires a coordinated national response. It also acknowledges and advocates the key roles to be played by stakeholders and the importance of forging strong partnerships to prevent and tackle cybercrime in Nigeria.
Abstract: To explore how the brain may recognise objects in its
general,accurate and energy-efficient manner, this paper proposes the
use of a neuromorphic hardware system formed from a Dynamic
Video Sensor (DVS) silicon retina in concert with the SpiNNaker
real-time Spiking Neural Network (SNN) simulator. As a first step
in the exploration on this platform a recognition system for dynamic
hand postures is developed, enabling the study of the methods used
in the visual pathways of the brain. Inspired by the behaviours of
the primary visual cortex, Convolutional Neural Networks (CNNs)
are modelled using both linear perceptrons and spiking Leaky
Integrate-and-Fire (LIF) neurons.
In this study’s largest configuration using these approaches, a
network of 74,210 neurons and 15,216,512 synapses is created and
operated in real-time using 290 SpiNNaker processor cores in parallel
and with 93.0% accuracy. A smaller network using only 1/10th of the
resources is also created, again operating in real-time, and it is able
to recognise the postures with an accuracy of around 86.4% - only
6.6% lower than the much larger system. The recognition rate of the
smaller network developed on this neuromorphic system is sufficient
for a successful hand posture recognition system, and demonstrates
a much improved cost to performance trade-off in its approach.
Abstract: Presently a significant portion of the Earth's
population does not have access to healthy food. Either because they
cannot afford it or because they do not know which one are they. The
aim of the VII th Framework Chance project (Nr. 266331) supported
by the European Union has been to develop relatively cheap food
with favourable nutritional value and it should have acceptable
quality for consumers. As one task of the project we manufactured
bread products as a basic food. We examined the enrichment of bread
products with four kinds of bran, with a special milling product of
grain industry (aleurone-rich flour) and with a soy-based sprouted
additive. The applied concentration of the six mentioned additives
has been optimized and the physical properties of the bread products
were monitored. The weight/density of the enriched breads increased
a bit, however the volume and height decreased slightly compared to
the corresponding data of the control bread. The optimized
composition of the final product is favourably affected by these
additives having highly preferred composition from nutritional point
of view.
Abstract: Distributed applications deployed on LEO satellites
and ground stations require substantial communication between
different members in a constellation to overcome the earth
coverage barriers imposed by GEOs. Applications running on LEO
constellations suffer the earth line-of-sight blockage effect. They
need adequate lab testing before launching to space. We propose
a scalable cloud-based network simulation framework to simulate
problems created by the earth line-of-sight blockage. The framework
utilized cloud IaaS virtual machines to simulate LEO satellites
and ground stations distributed software. A factorial ANOVA
statistical analysis is conducted to measure simulator overhead on
overall communication performance. The results showed a very low
simulator communication overhead. Consequently, the simulation
framework is proposed as a candidate for testing LEO constellations
with distributed software in the lab before space launch.
Abstract: Exploration and exploitation capabilities are both
important within Operations as means for improvement when
managed separately, and for establishing dynamic improvement
capabilities when combined in balance. However, it is unclear what
exploration and exploitation capabilities imply in improvement and
development work within an Operations context. So, in order to
better understand how to develop exploration and exploitation
capabilities within Operations, the main characteristics of these
constructs needs to be identified and further understood. Thus, the
objective of this research is to increase the understanding about
exploitation and exploration characteristics, to concretize what they
translates to within the context of improvement and development
work in an Operations unit, and to identify practical challenges. A
literature review and a case study are presented. In the literature
review, different interpretations of exploration and exploitation are
portrayed, key characteristics have been identified, and a deepened
understanding of exploration and exploitation characteristics is
described. The case in the study is an Operations unit, and the aim is
to explore to what extent and in what ways exploration and
exploitation activities are part of the improvement structures and
processes. The contribution includes an identification of key
characteristics of exploitation and exploration, as well as an
interpretation of the constructs. Further, some practical challenges are
identified. For instance, exploration activities tend to be given low
priority, both in daily work as in the manufacturing strategy. Also,
the overall understanding about the concepts of exploitation and
exploration (or any similar aspect of dynamic improvement
capabilities) is very low.
Abstract: Metal thin-walled members have been widely used in
building industry. Usually they are utilized as purlins, girts or ceiling
beams. Due to slenderness of thin-walled cross-sections these
structural members are prone to stability problems (e.g. flexural
buckling, lateral torsional buckling). If buckling is not
constructionally prevented their resistance is limited by buckling
strength. In practice planar members of roof or wall cladding can be
attached to thin-walled members. These elements reduce
displacement of thin-walled members and therefore increase their
buckling strength. If this effect is taken into static assessment more
economical sections of thin-walled members might be utilized and
certain savings of material might be achieved. This paper focuses on
problem of determination of critical load of steel thin-walled beams
with lateral continuous restraint which is crucial for lateral torsional
buckling assessment.