Abstract: This paper presents the experimental as well as the
simulated performance studies on the transcritical CO2 heat pumps
for simultaneous water cooling and heating; effects of water mass
flow rates and water inlet temperatures of both evaporator and gas
cooler on the cooling and heating capacities, system COP and water
outlets temperatures are investigated. Study shows that both the
water mass flow rate and inlet temperature have significant effect on
system performances. Test results show that the effect of evaporator
water mass flow rate on the system performances and water outlet
temperatures is more pronounced (COP increases 0.6 for 1 kg/min)
compared to the gas cooler water mass flow rate (COP increases 0.4
for 1 kg/min) and the effect of gas cooler water inlet temperature is
more significant (COP decreases 0.48 for given ranges) compared to
the evaporator water inlet temperature (COP increases 0.43 for given
ranges). Comparisons of experimental values with simulated results
show the maximum deviation of 5% for cooling capacity, 10% for
heating capacity, 16% for system COP. This study offers useful
guidelines for selecting appropriate water mass flow rate to obtain
required system performance.
Abstract: In this paper, an erosion-based model for abrasive
waterjet (AWJ) turning process is presented. By using modified
Hashish erosion model, the volume of material removed by impacting
of abrasive particles to surface of the rotating cylindrical specimen is
estimated and radius reduction at each rotation is calculated.
Different to previous works, the proposed model considers the
continuous change in local impact angle due to change in workpiece
diameter, axial traverse rate of the jet, the abrasive particle roundness
and density. The accuracy of the proposed model is examined by
experimental tests under various traverse rates. The final diameters
estimated by the proposed model are in good accordance with
experiments.
Abstract: Experiments have been carried out at the Latvia
University of Agriculture Department of Food Technology. The aim
of this work was to assess the effect of sous vide packaging during
the storage time of salad with meat in mayonnaise at different storage
temperature. Samples were evaluated at 0, 1, 3, 7, 10, 15, 18, 25, 29,
42, and 52 storage days at the storage temperature of +4±0.5 ºC and
+10±0.5 ºC. Experimentally the quality of the salad with meat in
mayonnaise was characterized by measuring colour, pH and
microbiological properties. The sous vide packaging was effective in
protecting the product from physical, chemical, and microbial quality
degradation. The sous vide packaging significantly reduces microbial
growth at storage temperature of +4±0.5 ºC and +10±0.5 ºC.
Moreover, it is possible to extend the product shelf life to 52 days
even when stored at +10±0.5 ºC.
Abstract: The present study was provided to examine the
vortical structures generated by two inclined impinging jets with
experimental and numerical investigations. The jets are issuing with a
pitch angle α=40° into a confined quiescent fluid. The experimental
investigation on flow patterns was visualized by using olive particles
injected into the jets illuminated by Nd:Yag laser light to reveal the
finer details of the confined jets interaction. It was observed that two
counter-rotating vortex pairs (CVPs) were generated in the near
region. A numerical investigation was also performed. First, the
numerical results were validates against the experimental results and
then the numerical model was used to study the effect of section ratio
on the evolution of the CVPs. Our results show promising agreement
with experimental data, and indicate that our model has the potential
to produce useful and accurate data regarding the evolution of CVPs.
Abstract: A spatial classification technique incorporating a State of Art Feature Extraction algorithm is proposed in this paper for classifying a heterogeneous classes present in hyper spectral images. The classification accuracy can be improved if and only if both the feature extraction and classifier selection are proper. As the classes in the hyper spectral images are assumed to have different textures, textural classification is entertained. Run Length feature extraction is entailed along with the Principal Components and Independent Components. A Hyperspectral Image of Indiana Site taken by AVIRIS is inducted for the experiment. Among the original 220 bands, a subset of 120 bands is selected. Gray Level Run Length Matrix (GLRLM) is calculated for the selected forty bands. From GLRLMs the Run Length features for individual pixels are calculated. The Principle Components are calculated for other forty bands. Independent Components are calculated for next forty bands. As Principal & Independent Components have the ability to represent the textural content of pixels, they are treated as features. The summation of Run Length features, Principal Components, and Independent Components forms the Combined Features which are used for classification. SVM with Binary Hierarchical Tree is used to classify the hyper spectral image. Results are validated with ground truth and accuracies are calculated.
Abstract: The effect of dry milling on the carbothermic
reduction of celestite was investigated. Mixtures of celestite
concentrate (98% SrSO4) and activated carbon (99% carbon) was
milled for 1 and 24 hours in a planetary ball mill. Un-milled and
milled mixtures and their products after carbothermic reduction were
studied by a combination of XRD and TGA/DTA experiments. The
thermogravimetric analyses and XRD results showed that by milling
celestite-carbon mixtures for one hour, the formation temperature of
strontium sulfide decreased from about 720°C (in un-milled sample)
to about 600°C, after 24 hours milling it decreased to 530°C. It was
concluded that milling induces increasingly thorough mixing of the
reactants to reduction occurring at lower temperatures
Abstract: The purpose of this article is to study the effects of
plants cover on overland flow and, therefore, its influences on the
amount of eroded and transported soil. In this investigation, all the
experiments were conducted in the LEGHYD laboratory using a
rainfall simulator and a soil tray. The experiments were conducted
using an experimental plot (soil tray) which is 2m long, 0.5 m wide
and 0.15 m deep. The soil used is an agricultural sandy soil (62,08%
coarse sand, 19,14% fine sand, 11,57% silt and 7,21% clay). Plastic
rods (4 mm in diameter) were used to simulate the plants at different
densities: 0 stem/m2 (bared soil), 126 stems/m², 203 stems/m², 461
stems/m² and 2500 stems/m²). The used rainfall intensity is 73mm/h
and the soil tray slope is fixed to 3°. The results have shown that the
overland flow velocities decreased with increasing stems density, and
the density cover has a great effect on sediment concentration.
Darcy–Weisbach and Manning friction coefficients of overland flow
increased when the stems density increased. Froude and Reynolds
numbers decreased with increasing stems density and, consequently,
the flow regime of all treatments was laminar and subcritical. From
these findings, we conclude that increasing the plants cover can
efficiently reduce soil loss and avoid denuding the roots plants.
Abstract: The contact width is important design parameter for
optimizing the design of new metal gasket for asbestos substitution
gasket. The contact width is found have relationship with the helium
leak quantity. In the increasing of axial load value, the helium leak
quantity is decreasing and the contact width is increasing. This study
provides validity method using simulation analysis and the result is
compared to experimental using pressure sensitive paper. The results
denote similar trend data between simulation and experimental result.
Final evaluation is determined by helium leak quantity to check
leakage performance of gasket design. Considering the phenomena of
position change on the convex contact, it can be developed the
optimization of gasket design by increasing contact width.
Abstract: Emotion recognition is an important research field that finds lots of applications nowadays. This work emphasizes on recognizing different emotions from speech signal. The extracted features are related to statistics of pitch, formants, and energy contours, as well as spectral, perceptual and temporal features, jitter, and shimmer. The Artificial Neural Networks (ANN) was chosen as the classifier. Working on finding a robust and fast ANN classifier suitable for different real life application is our concern. Several experiments were carried out on different ANN to investigate the different factors that impact the classification success rate. Using a database containing 7 different emotions, it will be shown that with a proper and careful adjustment of features format, training data sorting, number of features selected and even the ANN type and architecture used, a success rate of 85% or even more can be achieved without increasing the system complicity and the computation time
Abstract: This work deals with aspects of support vector machine learning for large-scale data mining tasks. Based on a decomposition algorithm for support vector machine training that can be run in serial as well as shared memory parallel mode we introduce a transformation of the training data that allows for the usage of an expensive generalized kernel without additional costs. We present experiments for the Gaussian kernel, but usage of other kernel functions is possible, too. In order to further speed up the decomposition algorithm we analyze the critical problem of working set selection for large training data sets. In addition, we analyze the influence of the working set sizes onto the scalability of the parallel decomposition scheme. Our tests and conclusions led to several modifications of the algorithm and the improvement of overall support vector machine learning performance. Our method allows for using extensive parameter search methods to optimize classification accuracy.
Abstract: Since dealing with high dimensional data is
computationally complex and sometimes even intractable, recently
several feature reductions methods have been developed to reduce
the dimensionality of the data in order to simplify the calculation
analysis in various applications such as text categorization, signal
processing, image retrieval, gene expressions and etc. Among feature
reduction techniques, feature selection is one the most popular
methods due to the preservation of the original features.
In this paper, we propose a new unsupervised feature selection
method which will remove redundant features from the original
feature space by the use of probability density functions of various
features. To show the effectiveness of the proposed method, popular
feature selection methods have been implemented and compared.
Experimental results on the several datasets derived from UCI
repository database, illustrate the effectiveness of our proposed
methods in comparison with the other compared methods in terms of
both classification accuracy and the number of selected features.
Abstract: Stock portfolio selection is a classic problem in finance,
and it involves deciding how to allocate an institution-s or an individual-s
wealth to a number of stocks, with certain investment objectives
(return and risk). In this paper, we adopt the classical Markowitz
mean-variance model and consider an additional common realistic
constraint, namely, the cardinality constraint. Thus, stock portfolio
optimization becomes a mixed-integer quadratic programming problem
and it is difficult to be solved by exact optimization algorithms.
Chemical Reaction Optimization (CRO), which mimics the molecular
interactions in a chemical reaction process, is a population-based
metaheuristic method. Two different types of CRO, named canonical
CRO and Super Molecule-based CRO (S-CRO), are proposed to solve
the stock portfolio selection problem. We test both canonical CRO
and S-CRO on a benchmark and compare their performance under
two criteria: Markowitz efficient frontier (Pareto frontier) and Sharpe
ratio. Computational experiments suggest that S-CRO is promising
in handling the stock portfolio optimization problem.
Abstract: This paper objects to extend Jon Kleinberg-s research. He introduced the structure of small-world in a grid and shows with a greedy algorithm using only local information able to find route between source and target in delivery time O(log2n). His fundamental model for distributed system uses a two-dimensional grid with longrange random links added between any two node u and v with a probability proportional to distance d(u,v)-2. We propose with an additional information of the long link nearby, we can find the shorter path. We apply the ant colony system as a messenger distributed their pheromone, the long-link details, in surrounding area. The subsequence forwarding decision has more option to move to, select among local neighbors or send to node has long link closer to its target. Our experiment results sustain our approach, the average routing time by Color Pheromone faster than greedy method.
Abstract: As far as the latest technological improvements are concerned, digital systems more become popular than the past. Despite this growing demand to the digital systems, content copy and attack against the digital cinema contents becomes a serious problem. To solve the above security problem, we propose “traceable watermarking using Hash functions for digital cinema system. Digital Cinema is a great application for traceable watermarking since it uses watermarking technology during content play as well as content transmission. The watermark is embedded into the randomly selected movie frames using CRC-32 techniques. CRC-32 is a Hash function. Using it, the embedding position is distributed by Hash Function so that any party cannot break off the watermarking or will not be able to change. Finally, our experimental results show that proposed DWT watermarking method using CRC-32 is much better than the convenient watermarking techniques in terms of robustness, image quality and its simple but unbreakable algorithm.
Abstract: The purpose of this study is to design a portable virtual
piano. By utilizing optical fiber gloves and the virtual piano software
designed by this study, the user can play the piano anywhere at any
time. This virtual piano consists of three major parts: finger tapping
identification, hand movement and positioning identification, and
MIDI software sound effect simulation. To play the virtual piano, the
user wears optical fiber gloves and simulates piano key tapping
motions. The finger bending information detected by the optical fiber
gloves can tell when piano key tapping motions are made. Images
captured by a video camera are analyzed, hand locations and moving
directions are positioned, and the corresponding scales are found. The
system integrates finger tapping identification with information about
hand placement in relation to corresponding piano key positions, and
generates MIDI piano sound effects based on this data. This
experiment shows that the proposed method achieves an accuracy rate
of 95% for determining when a piano key is tapped.
Abstract: This paper presents an approach for repairing word order errors in English text by reordering words in a sentence and choosing the version that maximizes the number of trigram hits according to a language model. A possible way for reordering the words is to use all the permutations. The problem is that for a sentence with length N words the number of all permutations is N!. The novelty of this method concerns the use of an efficient confusion matrix technique for reordering the words. The confusion matrix technique has been designed in order to reduce the search space among permuted sentences. The limitation of search space is succeeded using the statistical inference of N-grams. The results of this technique are very interesting and prove that the number of permuted sentences can be reduced by 98,16%. For experimental purposes a test set of TOEFL sentences was used and the results show that more than 95% can be repaired using the proposed method.
Abstract: Experiments were carried out at the Faculty of Food
Technology of Latvia University of Agriculture (LLU). Soft cheese
Kleo produced in Latvia was packed in a biodegradable PLA without
barrierproperties and VC999 BioPack lidding film PLA, coated with
a barrier of pure silicon oxide (SiOx) and in combination with
modified atmosphere (MAP) the influence on the shelf life was
investigated and compared with some conventional (OPP, PE/PA,
PE/OPA and Multibarrier 60) polymer film impact. Modified
atmosphere consisted of carbon dioxide CO2 (E 290) 30% and
nitrogen N2 (E 941) 70%. The analyzable samples were stored at the
temperature of +4.0±0.5 °C up to 32 days- and analyzed before
packaging and in the 0, 5th, 11th, 15th, 18th, 22nd, 25th, 29th and 32nd
day of storage. The shelf life was extended along to 32 days, good
outside appearance and lactic acid aroma was observed.
Abstract: The common practice of operating S-rotor is in an
open environment; however there are times when the rotor is
installed in a bounded environment and there might be changes in the
performance of the rotor. This paper presents the changes in the
performance of S-rotor when operated in bounded flows. The
investigation was conducted experimentally to compare the
performance of the rotors in bounded environment against open
environment. Three different rotors models were designed, fabricated
and subjected to experimental measurements. All of the three models
were having 600 mm height and 300 mm Diameter. They were tested
in three different flow environments; namely: partially bounded
environment, fully bounded environment and open environment.
Rotors were found to have better starting up capabilities when
operated in bounded environment. Apart from that, all rotors manage
to achieve higher Power and Torque Coefficients at a higher Tip
Speed Ratio as compared to the open environment.
Abstract: This paper presents a novel approach to assessing textile porosity by the application of the image analysis techniques. The images of different types of sample fabrics, taken through a microscope when the fabric is placed over a constant light source,transfer the problem into the image analysis domain. Indeed, porosity can thus be expressed in terms of a brightness percentage index calculated on the digital microscope image. Furthermore, it is meaningful to compare the brightness percentage index with the air permeability and the tightness indices of each fabric type. We have experimentally shown that there exists an approximately linear relation between brightness percentage and air permeability indices.
Abstract: Intelligent tutoring systems constitute an evolution of computer-aided educational software. We present here the modules of an intelligent tutoring system for Automatic Control, developed in our department. Through the software application developed,students can perform complete automatic control laboratory experiments, either over the departmental local area network or over the Internet. Monitoring of access to the system (local as well as international), along with student performance statistics, has yielded strongly encouraging results (as of fall 2004), despite the advanced technical content of the presented paradigm, thus showing the potential of the system developed for education and for training.