Abstract: In competitive electricity markets all over the world, an adoption of suitable transmission pricing model is a problem as transmission segment still operates as a monopoly. Transmission pricing is an important tool to promote investment for various transmission services in order to provide economic, secure and reliable electricity to bulk and retail customers. The nodal pricing based on SRMC (Short Run Marginal Cost) is found extremely useful by researchers for sending correct economic signals. The marginal prices must be determined as a part of solution to optimization problem i.e. to maximize the social welfare. The need to maximize the social welfare subject to number of system operational constraints is a major challenge from computation and societal point of views. The purpose of this paper is to present a nodal transmission pricing model based on SRMC by developing new mathematical expressions of real and reactive power marginal prices using GA-Fuzzy based optimal power flow framework. The impacts of selecting different social welfare functions on power marginal prices are analyzed and verified with results reported in literature. Network revenues for two different power systems are determined using expressions derived for real and reactive power marginal prices in this paper.
Abstract: Solid oxide fuel cells have been considered in the last years as one of the most promising technologies for very highefficiency electric energy generation from hydrogen or other hydrocarbons, both with simple fuel cell plants and with integrated gas turbine-fuel cell systems. In the present study, a detailed thermodynamic analysis has been carried out. Mass and exergy balances are performed not only for the whole plant but also for each component in order to evaluate the thermal efficiency of combined cycle. Moreover, different sources of irreversibilities within the SOFC stack have been discussed and a parametric study conducted to evaluate the effect of temperature as well as pressure on SOFC irreversibilities and its performance. In this investigation methane and hydrogen have been used for fueling the SOFC stack and combustion chamber.
Abstract: According to investigating impact of complexity of
stereoscopic frame pairs on stereoscopic video coding and
transmission, a new rate control algorithm is presented. The proposed
rate control algorithm is performed on three levels: stereoscopic group
of pictures (SGOP) level, stereoscopic frame (SFrame) level and
frame level. A temporal-spatial frame complexity model is firstly
established, in the bits allocation stage, the frame complexity, position
significance and reference property between the left and right frames
are taken into account. Meanwhile, the target buffer is set according to
the frame complexity. Experimental results show that the proposed
method can efficiently control the bitrates, and it outperforms the fixed
quantization parameter method from the rate distortion perspective,
and average PSNR gain between rate-distortion curves (BDPSNR) is
0.21dB.
Abstract: Arenga pinnata is an abundantly natural fiber that can be used for sound proof material. However, the scientific data of acoustics properties of Arenga pinnata was not available yet. In this study the sound absorption of pure arenga pinnata was measured. The thickness of Arenga pinnata was varied in 10 mm, 20 mm, 30mm, and 40mm. This work was carried out to investigate the potential of using Arenga pinnata fiber as raw material for sound absorbing material. Impedance Tube Method was used to measure sound absorption coefficient (α). The Measurements was done in accordance with ASTM E1050-98, that is the standard test method for impedance and absorption of acoustical materials using a tube, two microphones and a digital frequency analysis system . The results showed that sound absorption coefficients of Arenga pinnata were good from 2000 Hz to 5000 Hz within the range of 0.75 – 0.90. The optimum sound absorption coefficient was obtained from the thickness of 40 mm. These results indicated that Arenga pinnata fiber is promising to be used as raw material of sound absorbing material with low cost, light, and biodegradable.
Abstract: The demand on High voltage (HV) infrastructures is growing due to the corresponding growth in industries and population. New or upgraded HV infrastructure has safety implications since Transmission mains usually occupy the same easement in the vicinity of neighbouring residents. Transmission mains consist of underground (UG) and overhead (OH) sections and the transition between the UG and OH section is known as the UGOH pole. The existence of two transmission mains in the same easement can dictate to resort to more complicated earthing design in order to mitigate the effect of AC interference, and in some cases it can also necessitates completing a Split Study of the system. This paper provides an overview of the AC interference, Split Study and the earthing of an underground feeder including the UGOH pole .In addition, this paper discusses the use of different link boxes on the UG feeder and presents a case study that represent a clear example of the Ac interference and Split factor. Finally, a few recommendations are provided to achieve a safety zone in the area beyond the boundary of the HV system.
Abstract: The performance of modified Fenton (MF) treatment
to promote PAH oxidation in artificially contaminated soil was
investigated in packed soil column with a hydrogen peroxide (H2O2)
delivery system simulating in situ injection. Soil samples were spiked
with phenanthrene (low molecular weight PAH) and fluoranthene
(high molecular weight PAH) to an initial concentration of 500
mg/kg dried soil each. The effectiveness of process parameters
H2O2/soil, iron/soil, chelating agent/soil weight ratios and reaction
time were studied using a 24 three level factorial design experiments.
Statistically significant quadratic models were developed using
Response Surface Methodology (RSM) for degrading PAHs from the
soil samples. Optimum operating condition was achieved at mild
range of H2O2/soil, iron/soil and chelating agent/soil weight ratios,
indicating cost efficient method for treating highly contaminated
lands.
Abstract: The quality-of-service (QoS) support for wireless
LANs has been a hot research topic during the past few years. In this paper, two QoS provisioning mechanisms are proposed for the employment in 802.11e EDCA MAC scheme. First, the proposed call
admission control mechanism can not only guarantee the QoS for the higher priority existing connections but also provide the minimum reserved bandwidth for traffic flows with lower priority. In addition, the adaptive contention window adjustment mechanism can adjust the
maximum and minimum contention window size dynamically according to the existing connection number of each AC. The collision
probability as well as the packet delay will thus be reduced effectively.
Performance results via simulations have revealed the enhanced QoS property achieved by employing these two mechanisms.
Abstract: This paper presents a review of an 8-year study on radiation effects in commercial memory devices operating within the main on-board computer system OBC386 of the Algerian microsatellite Alsat-1. A statistical analysis of single-event upset (SEU) and multiple-bit upset (MBU) activity in these commercial memories shows that the typical SEU rate at alsat-1's orbit is 4.04 × 10-7 SEU/bit/day, where 98.6% of these SEUs cause single-bit errors, 1.22% cause double-byte errors, and the remaining SEUs result in multiple-bit and severe errors.
Abstract: This paper presents a model for analysis the induced voltage of transmission lines (energized) acting on neighboring distribution lines (de-energized). From environmental restrictions, 22 kV distribution lines need to be installed under 115 kV transmission lines. With the installation of the two parallel circuits like this, they make the induced voltage which can cause harm to operators. This work was performed with the ATP-EMTP modeling to analyze such phenomenon before field testing. Simulation results are used to find solutions to prevent danger to operators who are on the pole.
Abstract: K-Modes is an extension of K-Means clustering algorithm, developed to cluster the categorical data, where the mean is replaced by the mode. The similarity measure proposed by Huang is the simple matching or mismatching measure. Weight of attribute values contribute much in clustering; thus in this paper we propose a new weighted dissimilarity measure for K-Modes, based on the ratio of frequency of attribute values in the cluster and in the data set. The new weighted measure is experimented with the data sets obtained from the UCI data repository. The results are compared with K-Modes and K-representative, which show that the new measure generates clusters with high purity.
Abstract: The aim of this paper is to introduce and study a new concept of strong double χ2 (M,A, Δ) of fuzzy numbers and also some properties of the resulting sequence spaces of fuzzy numbers were examined.
Abstract: Sustainable development is a concept which was
originated in Burtland commission in 1978. Although this concept
was born with environmental aspects, it is penetrated in all areas
rapidly, turning into a dominate view of planning. Concentrating on
future generation issue, especially when talking about heritage has a
long story. Each approach with all of its characteristics illustrates
differences in planning, hence planning always reflects the dominate
idea of its age. This paper studies sustainable development in
planning for historical cities with the aim of finding ways to deal
with heritage in planning for historical cities in Iran. Through this, it
will be illustrated how challenges between sustainable concept and
heritage could be concluded in planning.
Consequently, the paper will emphasize on:
Sustainable development in city planning
Trends regarding heritage
Challenges due to planning for historical cities in Iran
For the first two issues, documentary method regarding the
sustainable development and heritage literature is considered. As the
next step focusing on Iranian historical cities require considering the
urban planning and management structure and identifying the main
challenges related to heritage, so analyzing challenges regarding
heritage is considered. As the result it would be illustrated that key
issue in such planning is active conservation to improve and use the
potential of heritage while it's continues conservation is guaranteed.
By emphasizing on the planning system in Iran it will be obvious that
some reforms are needed in this system and its way of relating with
heritage. The main weakness in planning for historical cities in Iran
is the lack of independent city management. Without this factor
achieving active conservation as the main factor of sustainable
development would not be possible.
Abstract: Nowadays, the focus on renewable energy and alternative fuels has increased due to increasing oil prices, environment pollution, and also concern on preserving the nature. Biodiesel has been known as an attractive alternative fuel although biodiesel produced from edible oil is very expensive than conventional diesel. Therefore, the uses of biodiesel produced from non-edible oils are much better option. Currently Jatropha biodiesel (JBD) is receiving attention as an alternative fuel for diesel engine. Biodiesel is non-toxic, biodegradable, high lubricant ability, highly renewable, and its use therefore produces real reduction in petroleum consumption and carbon dioxide (CO2) emissions. Although biodiesel has many advantages, but it still has several properties need to improve, such as lower calorific value, lower effective engine power, higher emission of nitrogen oxides (NOX) and greater sensitivity to low temperature. Exhaust gas recirculation (EGR) is effective technique to reduce NOX emission from diesel engines because it enables lower flame temperature and oxygen concentration in the combustion chamber. Some studies succeeded to reduce the NOX emission from biodiesel by EGR but they observed increasing soot emission. The aim of this study was to investigate the engine performance and soot emission by using blended Jatropha biodiesel with different EGR rates. A CI engine that is water-cooled, turbocharged, using indirect injection system was used for the investigation. Soot emission, NOX, CO2, carbon monoxide (CO) were recorded and various engine performance parameters were also evaluated.
Abstract: This study aims to explore the relationship between the
disposition effect and herding behavior of investors trading Taiwanese
information technology stocks. This study differs from previous
literature in two aspects. First, in contrast with the earlier studies that
focused on investigating investors’ herding behavior, this study
explores the possibility that the disposition effect drives investors’
herding behavior. Additionally, it takes an in-depth look at the
interdependence between the disposition effect and herding behavior
of investors, including lead-lag relationship and volatility transmission
effect. Empirical results show that investors trading Taiwan’s
information technology stocks exhibit pronounced herding behavior
and that the disposition effect has a great impact on their herding
behavior.
Abstract: Malaria is by far the world-s most persistent tropical parasitic disease and is endemic to tropical areas where the climatic and weather conditions allow continuous breeding of the mosquitoes that spread malaria. A mathematical model for the transmission of malaria with prophylaxis prevention is analyzed. The stability analysis of the equilibria is presented with the aim of finding threshold conditions under which malaria clears or persists in the human population. Our results suggest that eradication of mosquitoes and prophylaxis prevention can significantly reduce the malaria burden on the human population.
Abstract: Firstly, research and development on RFID focuses on
manufacturing and retail sectors, because it can improve supply chain
efficiency. But, now a variety of field is considered the next research
area for Radio Frequency Identification (RFID). Although RFID is
infancy, RFID technology has great potential in power industry to
significantly reduce cost, and improve quality of power supply. To
complement the limitation of RFID, we adopt the WSN (Wireless
Sensor Network) technology. However, relevant experience is limited,
the challenge will be to derive requirement from business practice and
to determine whether it is possible or not. To explore this issue, we
conduct a case study on implementing power facility management
system using RFID/WSN in Korea Electric Power Corporation
(KEPCO). In this paper we describe requirement from power industry.
And we introduce design and implementation of the test bed.
Abstract: The aerodynamic performances of vertical axis wind
turbines are highly affected by tip vortexes. In the present
work, different tip devices are considered and simulated against
a baseline rotor configuration, with the aim of identifying the
best tip architecture. Three different configurations are tested:
winglets, an elliptic termination and an aerodynamic bulkhead.
A comparative analysis on the most promising architectures is
conducted, focusing also on blade torque evolution during a full
revolution of the rotor blade. The most promising technology is
concluded to be a well designed winglet.
Abstract: Silk sericin (SS) is a glue-like protein from silkworm
cocoon. With its outstanding moisturization and activation collagen
synthesis properties, silk protein is applied for wound healing. Since
wound dressing in film preparation can facilitate patients-
convenience and reduce risk of wound contraction, SS and polyvinyl
alcohol (PVA) films were prepared with various concentrations of
SS. Their physical properties such as surface density, light
transmission, protein dissolution and tensile modulus were
investigated. The results presented that 3% SS with 2% PVA is the
best ingredient for SS film forming.
Abstract: Meshing is the process of discretizing problem
domain into many sub domains before the numerical calculation can
be performed. One of the most popular meshes among many types of meshes is tetrahedral mesh, due to their flexibility to fit into almost
any domain shape. In both 2D and 3D domains, triangular and tetrahedral meshes can be generated by using Delaunay triangulation.
The quality of mesh is an important factor in performing any Computational Fluid Dynamics (CFD) simulations as the results is
highly affected by the mesh quality. Many efforts had been done in
order to improve the quality of the mesh. The paper describes a mesh
generation routine which has been developed capable of generating
high quality tetrahedral cells in arbitrary complex geometry. A few
test cases in CFD problems are used for testing the mesh generator.
The result of the mesh is compared with the one generated by a
commercial software. The results show that no sliver exists for the
meshes generated, and the overall quality is acceptable since the percentage of the bad tetrahedral is relatively small. The boundary
recovery was also successfully done where all the missing faces are
rebuilt.
Abstract: The nature of wireless ad hoc and sensor networks
make them very attractive to attackers. One of the most popular and
serious attacks in wireless ad hoc networks is wormhole attack and
most proposed protocols to defend against this attack used
positioning devices, synchronized clocks, or directional antennas.
This paper analyzes the nature of wormhole attack and existing
methods of defending mechanism and then proposes round trip time
(RTT) and neighbor numbers based wormhole detection mechanism.
The consideration of proposed mechanism is the RTT between two
successive nodes and those nodes- neighbor number which is needed
to compare those values of other successive nodes. The identification
of wormhole attacks is based on the two faces. The first consideration
is that the transmission time between two wormhole attack affected
nodes is considerable higher than that between two normal neighbor
nodes. The second detection mechanism is based on the fact that by
introducing new links into the network, the adversary increases the
number of neighbors of the nodes within its radius. This system does
not require any specific hardware, has good performance and little
overhead and also does not consume extra energy. The proposed
system is designed in ad hoc on-demand distance vector (AODV)
routing protocol and analysis and simulations of the proposed system
are performed in network simulator (ns-2).