Abstract: A fast adaptive Tomlinson Harashima (T-H) precoder structure is presented for indoor wireless communications, where the channel may vary due to rotation and small movement of the mobile terminal. A frequency-selective slow fading channel which is time-invariant over a frame is assumed. In this adaptive T-H precoder, feedback coefficients are updated at the end of every uplink frame by using system identification technique for channel estimation in contrary with the conventional T-H precoding concept where the channel is estimated during the starting of the uplink frame via Wiener solution. In conventional T-H precoder it is assumed the channel is time-invariant in both uplink and downlink frames. However assuming the channel is time-invariant over only one frame instead of two, the proposed adaptive T-H precoder yields better performance than conventional T-H precoder if the channel is varied in uplink after receiving the training sequence.
Abstract: Multimedia security is an incredibly significant area of concern. The paper aims to discuss a robust image watermarking scheme, which can withstand geometric attacks. The source image is initially moment normalized in order to make it withstand geometric attacks. The moment normalized image is wavelet transformed. The first level wavelet transformed image is segmented into blocks if size 8x8. The product of mean and standard and standard deviation of each block is computed. The second level wavelet transformed image is divided into 8x8 blocks. The product of block mean and the standard deviation are computed. The difference between products in the two levels forms the watermark. The watermark is inserted by modulating the coefficients of the mid frequencies. The modulated image is inverse wavelet transformed and inverse moment normalized to generate the watermarked image. The watermarked image is now ready for transmission. The proposed scheme can be used to validate identification cards and financial instruments. The performance of this scheme has been evaluated using a set of parameters. Experimental results show the effectiveness of this scheme.
Abstract: The setting agent Ca(OH)2 for activation of slag
cement is used in the proportions of 0%, 2%, 4%, 6%, 8% and 10%
by various methods (substitution and addition by mass of slag
cement). The physical properties of slag cement activated by the
calcium hydroxide at anhydrous and hydrated states (fineness,
particle size distribution, consistency of the cement pastes and setting
times) were studied. The activation method by the mineral activator
of slag cement (latent hydraulicity) accelerates the hydration process
and reduces the setting times of the cement activated.
Abstract: The Norwegian Military Academy (Army) has been
using a tactical simulator for the last two years. During this time
there has been some discussion concerning how to use the simulator
most efficiently and what type of learning one achieves by using the
simulator. The problem that is addressed in this paper is how
simulators can be used as a learning resource for students concerned
with developing their military profession. The aim of this article is to
create a wider consciousness regarding the use of a simulator while
educating officers in a military profession. The article discusses the
use of simulators from two different perspectives. The first
perspective deals with using the simulator as a computer game, and
the second perspective looks at the simulator as a socio-cultural
artefact. Furthermore the article discusses four different ways the
simulator can be looked upon as a useful learning resource when
educating students of a military profession.
Abstract: This study deals with a multi-criteria optimization
problem which has been transformed into a single objective
optimization problem using Response Surface Methodology (RSM),
Artificial Neural Network (ANN) and Grey Relational Analyses
(GRA) approach. Grey-RSM and Grey-ANN are hybrid techniques
which can be used for solving multi-criteria optimization problem.
There have been two main purposes of this research as follows.
1. To determine optimum and robust fiber dyeing process
conditions by using RSM and ANN based on GRA,
2. To obtain the best suitable model by comparing models
developed by different methodologies.
The design variables for fiber dyeing process in textile are
temperature, time, softener, anti-static, material quantity, pH,
retarder, and dispergator. The quality characteristics to be evaluated
are nominal color consistency of fiber, maximum strength of fiber,
minimum color of dyeing solution. GRA-RSM with exact level
value, GRA-RSM with interval level value and GRA-ANN models
were compared based on GRA output value and MSE (Mean Square
Error) performance measurement of outputs with each other. As a
result, GRA-ANN with interval value model seems to be suitable
reducing the variation of dyeing process for GRA output value of the
model.
Abstract: As German companies roll out their standardized
production systems to offshore manufacturing plants, they face the
challenge of implementing them in different cultural environments.
Studies show that the local adaptation is one of the key factors for a
successful implementation. Thus the question arises of where the line
between standardization and adaptation can be drawn. To answer
this question the influence of culture on production systems is
analysed in this paper. The culturally contingent components of
production systems are identified. Also the contingency factors are
classified according to their impact on the necessary adaptation
changes and implementation effort. Culturally specific decision
making, coordination, communication and motivation patterns
require one-time changes in organizational and process design. The
attitude towards rules requires more intense coaching and controlling.
Lastly a framework is developed to depict standardization and
adaption needs when transplanting production systems into different
cultural environments.
Abstract: Multirate multimedia delivery applications in multihop Wireless Mesh Network (WMN) are data redundant and delay-sensitive, which brings a lot of challenges for designing efficient transmission systems. In this paper, we propose a new cross layer resource allocation scheme to minimize the receiver side distortion within the delay bound requirements, by exploring application layer Position and Value (P-V) diversity as well as the multihop Effective Capacity (EC). We specifically consider image transmission optimization here. First of all, the maximum supportable source traffic rate is identified by exploring the multihop Effective Capacity (EC) model. Furthermore, the optimal source coding rate is selected according to the P-V diversity of multirate media streaming, which significantly increases the decoded media quality. Simulation results show the proposed approach improved media quality significantly compared with traditional approaches under the same QoS requirements.
Abstract: This paper explores the implementation of adaptive
coding and modulation schemes for Multiple-Input Multiple-Output
Orthogonal Frequency Division Multiplexing (MIMO-OFDM) feedback
systems. Adaptive coding and modulation enables robust and
spectrally-efficient transmission over time-varying channels. The basic
premise is to estimate the channel at the receiver and feed this estimate
back to the transmitter, so that the transmission scheme can be
adapted relative to the channel characteristics. Two types of codebook
based channel feedback techniques are used in this work. The longterm
and short-term CSI at the transmitter is used for efficient channel
utilization. OFDM is a powerful technique employed in communication
systems suffering from frequency selectivity. Combined with
multiple antennas at the transmitter and receiver, OFDM proves to be
robust against delay spread. Moreover, it leads to significant data rates
with improved bit error performance over links having only a single
antenna at both the transmitter and receiver. The coded modulation
increases the effective transmit power relative to uncoded variablerate
variable-power MQAM performance for MIMO-OFDM feedback
system. Hence proposed arrangement becomes an attractive approach
to achieve enhanced spectral efficiency and improved error rate
performance for next generation high speed wireless communication
systems.
Abstract: Charging and discharging phenomenon on the surface
of materials can be found in plasma display panel, spacecraft
charging, high voltage insulator, etc. This report gives a simple
explanation on this phenomenon. A scanning electron microscope
was used not only as a tool to produce energetic electron beam to
charge an insulator without metallic coating and to produce a surface
discharging (surface breakdown/flashover) but also to observe the
visible charging and discharging on the sample surface. A model of
electric field distribution on the surface was developed in order to
explain charging and discharging phenomena. Since charging and
discharging process involves incubation time, therefore this process
can be used to evaluate the insulation property of materials under
electron bombardment.
Abstract: In these days, multimedia data is transmitted and
processed in compressed format. Due to the decoding procedure and
filtering for edge detection, the feature extraction process of MPEG-7
Edge Histogram Descriptor is time-consuming as well as
computationally expensive. To improve efficiency of compressed
image retrieval, we propose a new edge histogram generation
algorithm in DCT domain in this paper. Using the edge information
provided by only two AC coefficients of DCT coefficients, we can get
edge directions and strengths directly in DCT domain. The
experimental results demonstrate that our system has good
performance in terms of retrieval efficiency and effectiveness.
Abstract: Pressure wave velocity in a hydraulic system was
determined using piezo pressure sensors without removing fluid from
the system. The measurements were carried out in a low pressure
range (0.2 – 6 bar) and the results were compared with the results of
other studies. This method is not as accurate as measurement with
separate measurement equipment, but the fluid is in the actual
machine the whole time and the effect of air is taken into
consideration if air is present in the system. The amount of air is
estimated by calculations and comparisons between other studies.
This measurement equipment can also be installed in an existing
machine and it can be programmed so that it measures in real time.
Thus, it could be used e.g. to control dampers.
Abstract: Cross layer optimization based on utility functions has
been recently studied extensively, meanwhile, numerous types of
utility functions have been examined in the corresponding literature.
However, a major drawback is that most utility functions take a fixed
mathematical form or are based on simple combining, which can
not fully exploit available information. In this paper, we formulate a
framework of cross layer optimization based on Adaptively Weighted
Utility Functions (AWUF) for fairness balancing in OFDMA networks.
Under this framework, a two-step allocation algorithm is
provided as a sub-optimal solution, whose control parameters can be
updated in real-time to accommodate instantaneous QoS constrains.
The simulation results show that the proposed algorithm achieves
high throughput while balancing the fairness among multiple users.
Abstract: This paper discusses the approach of real-time
controlling of the energy management system using the data
acquisition tool of LabVIEW. The main idea of this inspiration was
to interface the Station (PC) with the system and publish the data on
internet using LabVIEW. In this venture, controlling and switching of
3 phase AC loads are effectively and efficiently done. The phases are
also sensed through devices. In case of any failure the attached
generator starts functioning automatically. The computer sends
command to the system and system respond to the request. The
modern feature is to access and control the system world-wide using
world wide web (internet). This controlling can be done at any time
from anywhere to effectively use the energy especially in developing
countries where energy management is a big problem. In this system
totally integrated devices are used to operate via remote location.
Abstract: In this research, a systematic investigation was carried out to determine the optimum conditions of HDS reactor. Moreover, a suitable model was developed for a rigorous RTO (real time optimization) loop of HDS (Hydro desulfurization) process. A systematic experimental series was designed based on CCD (Central Composite design) and carried out in the related pilot plant to tune the develop model. The designed variables in the experiments were Temperature, LHSV and pressure. However, the hydrogen over fresh feed ratio was remained constant. The ranges of these variables were respectively equal to 320-380ºC, 1- 21/hr and 50-55 bar. a power law kinetic model was also developed for our further research in the future .The rate order and activation energy , power of reactant concentration and frequency factor of this model was respectively equal to 1.4, 92.66 kJ/mol and k0=2.7*109 .
Abstract: Paced Auditory Serial Addition Test (PASAT) has
been used as a common research tool for different neurological
disorders like Multiple Sclerosis. Recently, technology let
researchers to introduce a new versions of the visual test, the paced
visual serial addition test (PVSAT). In this paper, the computerized
version of these two tests is introduced. Beside the number of true
responses are interpreted, the reaction time of subjects are calculated
by the software. We hypothesize that paying attention to the reaction
time may be valuable. For this purpose, sixty eight female normal
subjects and fifty eight male normal subjects are enrolled in the
study. We investigate the similarity between the PASAT3 and
PVSAT3 in number of true responses and the new criterion (the
average reaction time of each subject). The similarity between two
tests were rejected (p-value = 0.000) which means that these two test
differ. The effect of sex in the tests were not approved since the pvalues
of different between PASAT3 and PVSAT3 in both sex is the
same (p-value = 0.000) which means that male and female subjects
performed the tests at no different level of performance. The new
criterion shows a negative correlation with the age which offers aged
normal subjects may have the same number of true responses as the
young subjects but they have latent responses. This will give prove
for the importance of reaction time.
Abstract: The paper deals with the possibilities of modelling
vapour propagation of explosive substances in the FLUENT
software. With regard to very low tensions of explosive substance
vapours the experiment has been verified as exemplified by
mononitrotoluene. Either constant or time variable meteorological
conditions have been used for calculation. Further, it has been
verified that the eluent source may be time-dependent and may reflect
a real situation or the liberation rate may be constant. The execution
of the experiment as well as evaluation were clear and it could also
be used for modelling vapour and aerosol propagation of selected
explosive substances in the atmospheric boundary layer.
Abstract: In this paper, the melting of a semi-infinite body as a
result of a moving laser beam has been studied. Because the Fourier
heat transfer equation at short times and large dimensions does not
have sufficient accuracy; a non-Fourier form of heat transfer
equation has been used. Due to the fact that the beam is moving in x
direction, the temperature distribution and the melting pool shape are
not asymmetric. As a result, the problem is a transient threedimensional
problem. Therefore, thermophysical properties such as
heat conductivity coefficient, density and heat capacity are functions
of temperature and material states. The enthalpy technique, used for
the solution of phase change problems, has been used in an explicit
finite volume form for the hyperbolic heat transfer equation. This
technique has been used to calculate the transient temperature
distribution in the semi-infinite body and the growth rate of the melt
pool. In order to validate the numerical results, comparisons were
made with experimental data. Finally, the results of this paper were
compared with similar problem that has used the Fourier theory. The
comparison shows the influence of infinite speed of heat propagation
in Fourier theory on the temperature distribution and the melt pool
size.
Abstract: Checkpointing is one of the commonly used techniques to provide fault-tolerance in distributed systems so that the system can operate even if one or more components have failed. However, mobile computing systems are constrained by low bandwidth, mobility, lack of stable storage, frequent disconnections and limited battery life. Hence, checkpointing protocols having lesser number of synchronization messages and fewer checkpoints are preferred in mobile environment. There are two different approaches, although not orthogonal, to checkpoint mobile computing systems namely, time-based and index-based. Our protocol is a fusion of these two approaches, though not first of its kind. In the present exposition, an index-based checkpointing protocol has been developed, which uses time to indirectly coordinate the creation of consistent global checkpoints for mobile computing systems. The proposed algorithm is non-blocking, adaptive, and does not use any control message. Compared to other contemporary checkpointing algorithms, it is computationally more efficient because it takes lesser number of checkpoints and does not need to compute dependency relationships. A brief account of important and relevant works in both the fields, time-based and index-based, has also been included in the presentation.
Abstract: In this paper we present our results on the performance analysis of a multi-product manufacturing line. We study the influence of external perturbations, intermediate buffer content and the number of manufacturing stages on the production tracking error of each machine in the multi-product line operated under a surplusbased production control policy. Starting by the analysis of a single machine with multiple production stages (one for each product type), we provide bounds on the production error of each stage. Then, we extend our analysis to a line of multi-stage machines, where similarly, bounds on each production tracking error for each product type, as well as buffer content are obtained. Details on performance of the closed-loop flow line model are illustrated in numerical simulations.
Abstract: Low power consumption is a major constraint for battery-powered system like computer notebook or PDA. In the past, specialists usually designed both specific optimized equipments and codes to relief this concern. Doing like this could work for quite a long time, however, in this era, there is another significant restraint, the time to market. To be able to serve along the power constraint while can launch products in shorter production period, objectoriented programming (OOP) has stepped in to this field. Though everyone knows that OOP has quite much more overhead than assembly and procedural languages, development trend still heads to this new world, which contradicts with the target of low power consumption. Most of the prior power related software researches reported that OOP consumed much resource, however, as industry had to accept it due to business reasons, up to now, no papers yet had mentioned about how to choose the best OOP practice in this power limited boundary. This article is the pioneer that tries to specify and propose the optimized strategy in writing OOP software under energy concerned environment, based on quantitative real results. The language chosen for studying is C# based on .NET Framework 2.0 which is one of the trendy OOP development environments. The recommendation gotten from this research would be a good roadmap that can help developers in coding that well balances between time to market and time of battery.