Abstract: Plasma plume will be produced and arrive at spacecraft when the electric thruster operates on orbit. It-s important to characterize the thruster plasma parameters because the plume has significant effects or hazards on spacecraft sub-systems and parts. Through the ground test data of the desired parameters, the major characteristics of the thruster plume will be achieved. Also it is very important for optimizing design of Ion thruster. Retarding Potential Analyzer (RPA) is an effective instrument for plasma ion energy per unit charge distribution measurement. Special RPA should be designed according to certain plume plasma parameters range and feature. In this paper, major principles usable for good RPA design are discussed carefully. Conform to these principles, a four-grid planar electrostatic energy analyzer RPA was designed to avoid false data, and details were discussed including construction, materials, aperture diameter and so on. At the same time, it was designed more suitable for credible and long-duration measurements in the laboratory. In the end, RPA measurement results in the laboratory were given and discussed.
Abstract: An experiment was conducted under controlled
conditions to study the effect of water extract of leaves, shoots and
roots of either Sisymbrium irio L. =SISIR and or Descurainia
sophia (L.) Schur =DESSO on the germination and primary growth
of barley. A split-split plot experiment in CRD with three
replications was used. The main plots were the type of weed: i.e.
SISIR and DESSO and the sub-plots were type of organ: i.e. leaf,
stem and root and, the sub-sub plots were concentration of the
water extract of each organ of the weeds: i.e. 0, 2, 4 and 8 % w/v.
The results showed that the SISIR water extracts had a greater
inhibitory effects on the germination and primary growth of barley
than those of DESSO water extracts. The water extracts of the
leaves of both weeds had the greatest inhibitory effects on the
germination and primary growth of barley, compared to those of
stems and roots. Increasing the concentration of water extracts of
leaves, stems and roots of both weeds up to 8 % caused the greatest
inhibitory effects to barley and reduced the germination rate and
primary growth of it linearly.
Abstract: The knee bracing steel frame (KBF) is a new kind of energy dissipating frame, which combines excellent ductility and lateral stiffness. In this framing system, a special form of diagonal brace connected to a knee element instead of beam-column joint, is investigated. Recently, a similar system was proposed and named as chevron knee bracing system (CKB) which in comparison with the former system has a better energy absorption characteristic and at the same time retains the elastic nature of the structures. Knee bracing can provide a stiffer bracing system but reduces the ductility of the steel frame. Chevron knee bracing can be employed to provide the desired ductility level for a design. In this article, relation between seismic performance and structural parameters of the two above mentioned systems are investigated and compared. Frames with similar dimensions but various heights in both systems are designed according to Iranian code of practice for seismic resistant design of building, and then based on a non-linear push over static analysis; the seismic parameters such as behavior factor and performance levels are compared.
Abstract: With the exponentially increasing demand for
wireless communications the capacity of current cellular systems will
soon become incapable of handling the growing traffic. Since radio
frequencies are diminishing natural resources, there seems to be a
fundamental barrier to further capacity increase. The solution can be
found in smart antenna systems.
Smart or adaptive antenna arrays consist of an array of antenna
elements with signal processing capability, that optimize the
radiation and reception of a desired signal, dynamically. Smart
antennas can place nulls in the direction of interferers via adaptive
updating of weights linked to each antenna element. They thus cancel
out most of the co-channel interference resulting in better quality of
reception and lower dropped calls. Smart antennas can also track the
user within a cell via direction of arrival algorithms. This implies that
they are more advantageous than other antenna systems. This paper
focuses on few issues about the smart antennas in mobile radio
networks.
Abstract: The use of sewage sludge and effluents from
wastewater treatment plants for irrigation of agricultural lands is on
the rise particularly in peri-urban areas of developing countries.
The reuse of nutrients and organic matter in treated wastewater
and sewage sludge via land application is a desirable goal. However,
trace or heavy metals present in sludge pose the risk of human or
phytotoxicity from land application. Long-term use of sewage
sludge, heavy metals can accumulate to phytotoxic levels and results
in reduced plants growth and/or enhanced metal concentrations in
plants, which consumed by animals then enter the food chain. In this
research, the amount of heavy metals was measured in plants
irrigated with wastewater and sludge application. For this purpose,
three pilots were made in a Shush treatment plant in south of Tehran.
Three plants species, spinach, lettuce and radish were selected and
planted in the pilots.First pilot was irrigated just with wastewater of
treatment plant and second pilot was irrigated with wastewater and
sludge application .Third pilot was irrigated with simulated heavy
metals solution equal 50 years of irrigation. The results indicate that
the average of amount of heavy metals Pb, Cd in three plant species
in first pilot were lower than permissible limits .In second pilot,
Cadmium accumulations are high in three species plants and more
than the standard limits. Concentration of Cd , Pb have exceed their
permitted limits in plants in third pilot . It was concluded that the use
of wastewater and sludge application in agricultural lands enriched
soils with heavy metals to concentrations that may pose potential
environmental and health risks in the long-term.
Abstract: A procedural-animation-based approach which rapidly
synthesize the adaptive locomotion for quadruped characters that they
can walk or run in any directions on an uneven terrain within a
dynamic environment was proposed. We devise practical motion
models of the quadruped animals for adapting to a varied terrain in a
real-time manner. While synthesizing locomotion, we choose the
corresponding motion models by means of the footstep prediction of
the current state in the dynamic environment, adjust the key-frames of
the motion models relying on the terrain-s attributes, calculate the
collision-free legs- trajectories, and interpolate the key-frames
according to the legs- trajectories. Finally, we apply dynamic time
warping to each part of motion for seamlessly concatenating all desired
transition motions to complete the whole locomotion. We reduce the
time cost of producing the locomotion and takes virtual characters to
fit in with dynamic environments no matter when the environments are
changed by users.
Abstract: Both image steganography and image encryption have
advantages and disadvantages. Steganograhy allows us to hide a
desired image containing confidential information in a covered or
host image while image encryption is decomposing the desired image
to a non-readable, non-comprehended manner. The encryption
methods are usually much more robust than the steganographic ones.
However, they have a high visibility and would provoke the attackers
easily since it usually is obvious from an encrypted image that
something is hidden! The combination of steganography and
encryption will cover both of their weaknesses and therefore, it
increases the security. In this paper an image encryption method
based on sinc-convolution along with using an encryption key of 128
bit length is introduced. Then, the encrypted image is covered by a
host image using a modified version of JSteg steganography
algorithm. This method could be applied to almost all image formats
including TIF, BMP, GIF and JPEG. The experiment results show
that our method is able to hide a desired image with high security and
low visibility.
Abstract: This paper presents the new results of energy plant –
rye and triticale at yellow ripeness and ripe, pre-treatment in high
pressure steam reactor and monosaccharide extraction. There were
investigated the influence of steam pressure (20 to 22 bar), retention
duration (180 to 240 s) and catalytic sulphuric acid concentration
strength (0 to 0.5 %) on the pre-treatment process, contents of
monosaccharides (glucose, arabinose, xylose, mannose) and
undesirable by-compounds (furfural and HMF) in the reactor. The
study has determined that the largest amount of monosaccharides
(37.2 % of glucose, 2.7 % of arabinose, 8.4 % of xylose, and 1.3 %
of mannose) was received in the rye at ripe, the samples of which
were mixed with 0.5 % concentration of catalytic sulphuric acid, and
hydrolysed in the reactor, where the pressure was 20 bar, whereas the
reaction time – 240 s.
Abstract: This paper addresses a current problem that occurs among Thai internet service providers with regard to bandwidth network quality management. The IPSTAR department of Telecom Organization of Thailand public company (TOT); the largest internet service provider in Thailand, is the case study to analyze the problem that exists. The Internet bandwidth network quality management (iBWQM) framework is mainly applied to the problem that has been found. Bandwidth management policy (BMP) and quality of service (QoS) are two antecedents of iBWQM. This paper investigates internet user behavior, marketing demand and network operation views in order to determine bandwidth management policy (e.g. quota management, scheduling and malicious management). The congestion of bandwidth is also analyzed to enhance quality of service (QoS). Moreover, the iBWQM framework is able to improve the quality of service and increase bandwidth utilization, minimize complaint rate concerns to slow speed, and provide network planning guidelines through Thai Internet services providers.
Abstract: The whole-cell protein-profiling technique was
evaluated for studying differences in banding pattern of three
different species of Cyanobacteria i.e. Anabaena fertilissima,
Aulosira fertilissima and Westiellopsis prolifica under the influence
of four different pesticides-2,4-D (Ethyl Ester of 2,4-Dichloro
Phenoxy Acetic Acid), Pencycuron (N-[(4-chlorophenyl)methyl]-Ncyclopentyl-
N'–phenylurea), Endosulfan (6,7,8,9,10,10hexachloro-
1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepine-3-
oxide) and Tebuconazole (1-(4-Chlorophenyl)-4,4-dimethyl-3-(1,2,4-
triazol-1-ylmethyl)pentan-3-ol). Whole-cell extracts were obtained by
sonication treatment (Sonifier cell disruptor -Branson Digital Sonifier
S-450D, USA) and were analyzed by sodium dodecyl sulfate
polyacrylamide gel electrophoresis (SDS-PAGE). SDS-PAGE
analyses of the total protein profile of Anabaena fertilissima,
Aulosira fertilissima and Westiellopsis prolifica showed a linear
decrease in the protein content with increasing pesticide stress when
administered to different concentrations of 2, 4-D, Pencycuron,
Endosulfan and Tebuconazole. The results indicate that different
stressors exert specific effects on cyanobacterial protein synthesis.
Abstract: In this contribution, a way to enhance the performance of the classic Genetic Algorithm is proposed. The idea of restarting a Genetic Algorithm is applied in order to obtain better knowledge of the solution space of the problem. A new operator of 'insertion' is introduced so as to exploit (utilize) the information that has already been collected before the restarting procedure. Finally, numerical experiments comparing the performance of the classic Genetic Algorithm and the Genetic Algorithm with restartings, for some well known test functions, are given.
Abstract: In this paper, we consider nested sliding mode control of SISO nonlinear systems, perturbed by bounded matched and unmatched uncertainties. The systems are assumed to be in strict-feedback form. A step wise procedure is introduced to obtain the controller. In each step, a continuous sliding mode controller is designed as virtual control law. Then the next step sliding surface is defined by using this virtual controller. These sliding surfaces are selected as nonlinear static functions of the system states. Finally in the last step, smooth static state feedback control law is determined such that the output reaches the desired set-point while the system is forced arbitrary close to the intersection of sliding surfaces and the states remain bounded.
Abstract: Organochlorine pesticides (OCPs) are known to be
persistent and bioaccumulative toxicants that may cause reproductive
impairments in wildlife as well as human. The current study uses the
snail-eating turtle Malayemys macrocephala, a long-lived animal
commonly distribute in rice field habitat in central part of Thailand,
as a sentinel to monitor OCP contamination in environment. The
nest soil, complete clutch of eggs, and blood of the turtle were
collected from agricultural areas in the Chao Phraya River Basin,
Thailand during the nesting season of 2007-2008. The novel
methods for tissue extraction by an accelerated solvent extractor
(ASE, for egg) and liquid-liquid extraction (for blood) have been
developed. The nineteen OCP residues were analyzed by gas
chromatography with micro-electron captured detector (GC-μECD).
The validated methods have met requirements of the AOAC
standard. The results indicated that significant amounts of OCPs are
still contaminated in nest soil and eggs of the turtle even though the
OCPs had been banned in this area for many years. This suggested
the potential risk to health of wildlife as well as human in the area.
Abstract: The proper design of RF pulses in magnetic resonance imaging (MRI) has a direct impact on the quality of acquired images, and is needed for many applications. Several techniques have been proposed to obtain the RF pulse envelope given the desired slice profile. Unfortunately, these techniques do not take into account the limitations of practical implementation such as limited amplitude resolution. Moreover, implementing constraints for special RF pulses on most techniques is not possible. In this work, we propose to develop an approach for designing optimal RF pulses under theoretically any constraints. The new technique will pose the RF pulse design problem as a combinatorial optimization problem and uses efficient techniques from this area such as genetic algorithms (GA) to solve this problem. In particular, an objective function will be proposed as the norm of the difference between the desired profile and the one obtained from solving the Bloch equations for the current RF pulse design values. The proposed approach will be verified using analytical solution based RF simulations and compared to previous methods such as Shinnar-Le Roux (SLR) method, and analysis, selected, and tested the options and parameters that control the Genetic Algorithm (GA) can significantly affect its performance to get the best improved results and compared to previous works in this field. The results show a significant improvement over conventional design techniques, select the best options and parameters for GA to get most improvement over the previous works, and suggest the practicality of using of the new technique for most important applications as slice selection for large flip angles, in the area of unconventional spatial encoding, and another clinical use.
Abstract: This research paper designs a unique motion planner
of multiple platoons of nonholonomic car-like robots as a feasible
solution to the lane changing/merging maneuvers. The decentralized
planner with a leaderless approach and a path-guidance principle
derived from the Lyapunov-based control scheme generates collision
free avoidance and safe merging maneuvers from multiple lanes to a
single lane by deploying a split/merge strategy. The fixed obstacles
are the markings and boundaries of the road lanes, while the moving
obstacles are the robots themselves. Real and virtual road lane
markings and the boundaries of road lanes are incorporated into a
workspace to achieve the desired formation and configuration of the
robots. Convergence of the robots to goal configurations and the
repulsion of the robots from specified obstacles are achieved by
suitable attractive and repulsive potential field functions,
respectively. The results can be viewed as a significant contribution
to the avoidance algorithm of the intelligent vehicle systems (IVS).
Computer simulations highlight the effectiveness of the split/merge
strategy and the acceleration-based controllers.
Abstract: Transdermal delivery of ondansetron hydrochloride (OdHCl) can prevent the problems encountered with oral ondansetron. In previously conducted studies, effect of amount of polyvinyl pyrrolidone, permeation enhancer and casting solvent on the physicochemical properties on OdHCl were investigated. It is feasible to develop ondansetron transdermal patch by using ethyl cellulose and polyvinyl pyrrolidone with dibutyl pthalate as plasticizer, however, the desired flux is not achieved. The primary aim of this study is to use dimethyl succinate (DMS) and propylene glycol that are not incorporated in previous studies to determine their effect on the physicochemical properties of an OdHCl transdermal patch using ethyl cellulose and polyvinyl pyrrolidone. This study also investigates the effect of permeation enhancer (eugenol and phosphatidylcholine) on the release of OdHCl. The results showed that propylene glycol is a more suitable plasticizer compared to DMS in the fabrication of OdHCl transdermal patch using ethyl cellulose and polyvinyl pyrrolidone as polymers. Propylene glycol containing patch has optimum drug content, thickness, moisture content and water absorption, tensile strength, and a better release profile than DMS. Eugenol and phosphatidylcholine can increase release of OdHCl from the patches. From the physicochemical result and permeation profile, a combination of 350mg of ethyl cellulose, 150mg polyvinyl pyrrolidone, 3% of total polymer weight of eugenol, and 40% of total polymer weight of propylene glycol is the most suitable formulation to develop an OdHCl patch. OdHCl release did not increase with increasing the percentage of plasticiser. DMS 4, PG 4, DMS 9, PG 9, DMS 14, and PG 14 gave better release profiles where using 300mg: 0mg, 300mg: 100mg, and 350mg: 150mg of EC: PVP. Thus, 40% of PG or DMS appeared to be the optimum amount of plasticiser when the above combination where EC: PVP was used. It was concluded from the study that a patch formulation containing 350mg EC, 150mg PVP, 40% PG and 3% eugenol is the best transdermal matrix patch compositions for the uniform and continuous release/permeation of OdHCl over an extended period. This patch design can be used for further pharmacokinetic and pharmacodynamic studies in suitable animal models.
Abstract: The improvement of irrigation systems in the Nile
Delta is one of the most important attempts in Egypt to implement
more effective irrigation technology by improving the existing
irrigation networks. Demand delivery system in the existing irrigation
network is using of mechanical gates structures to automatically
divert water from one portion of an agricultural field to another in the
desired amount and sequence. This paper discusses evaluating main
irrigation networks system under the government managed before
and after improvement systems in the Nile Delta. The overall results
indicate that policy of using the demand delivery concept through
irrigation networks is successful by improving water delivery
performance among them than the rotation delivery concept that used
before. It is provided fair share of water delivery among irrigation
districts and available water in the end of irrigation network,
although this system located in an end of irrigation networks in the
Nile Delta.
Abstract: Performance of any continuous speech recognition system is highly dependent on performance of the acoustic models. Generally, development of the robust spoken language technology relies on the availability of large amounts of data. Common way to cope with little data for training each state of Markov models is treebased state tying. This tying method applies contextual questions to tie states. Manual procedure for question generation suffers from human errors and is time consuming. Various automatically generated questions are used to construct decision tree. There are three approaches to generate questions to construct HMMs based on decision tree. One approach is based on misrecognized phonemes, another approach basically uses feature table and the other is based on state distributions corresponding to context-independent subword units. In this paper, all these methods of automatic question generation are applied to the decision tree on FARSDAT corpus in Persian language and their results are compared with those of manually generated questions. The results show that automatically generated questions yield much better results and can replace manually generated questions in Persian language.
Abstract: In this paper, we study the formation control problem
for car-like mobile robots. A team of nonholonomic mobile robots navigate in a terrain with obstacles, while maintaining a desired
formation, using a leader-following strategy. A set of artificial potential field functions is proposed using the direct Lyapunov
method for the avoidance of obstacles and attraction to their designated targets. The effectiveness of the proposed control laws to verify the feasibility of the model is demonstrated through computer simulations
Abstract: This paper represents four unsupervised clustering algorithms namely sIB, RandomFlatClustering, FarthestFirst, and FilteredClusterer that previously works have not been used for network traffic classification. The methodology, the result, the products of the cluster and evaluation of these algorithms with efficiency of each algorithm from accuracy are shown. Otherwise, the efficiency of these algorithms considering form the time that it use to generate the cluster quickly and correctly. Our work study and test the best algorithm by using classify traffic anomaly in network traffic with different attribute that have not been used before. We analyses the algorithm that have the best efficiency or the best learning and compare it to the previously used (K-Means). Our research will be use to develop anomaly detection system to more efficiency and more require in the future.