Abstract: In an electric power system, spinning reserve
requirements can be determined by using deterministic and/or
probabilistic measures. Although deterministic methods are usual in
many systems, application of probabilistic methods becomes
increasingly important in the new environment of the electric power
utility industry. This is because of the increased uncertainty
associated with competition. In this paper 1) a new probabilistic
method is presented which considers the reliability of transmission
system in a simplified manner and 2) deterministic and probabilistic
methods are compared. The studied methods are applied to the Roy
Billinton Test System (RBTS).
Abstract: Transient Stability is an important issue in power systems planning, operation and extension. The objective of transient stability analysis problem is not satisfied with mere transient instability detection or evaluation and it is most important to complement it by defining fast and efficient control measures in order to ensure system security. This paper presents a new Fuzzy Support Vector Machines (FSVM) to investigate the stability status of power systems and a modified generation rescheduling scheme to bring back the identified unstable cases to a more economical and stable operating point. FSVM improves the traditional SVM (Support Vector Machines) by adding fuzzy membership to each training sample to indicate the degree of membership of this sample to different classes. The preventive control based on economic generator rescheduling avoids the instability of the power systems with minimum change in operating cost under disturbed conditions. Numerical results on the New England 39 bus test system show the effectiveness of the proposed method.
Abstract: Hospitals in southern Hualien teamed with the
Hypertension Joint Care Network. Working with the network, the
team provided a special designed health education to the individual
who had been identified as a hypertension patient in the outpatient
department. Some metabolism improvements achieved. This is a
retrospective study by purposively taking 106 patients from a hospital
between 2008 and 2010. Records of before and after education
intervention of the objects was collected and analyzed to see the how
the intervention affected the patients- hypertension control via clinical
parameter monitoring. The results showed that the clinical indicators,
the LDL-C, the cholesterol and the systolic blood pressure were
significantly improved. The study provides evidence for the
effectiveness of the network in controlling hypertension.
Abstract: By analyzing the sources of energy and power
loss in PWM (Pulse Width Modulation) controlled drivers of
water electrolysis cells, it is possible to reduce the power
dissipation and enhance the efficiency of such hydrogen
production units. A PWM controlled power driver is based on
a semiconductor switching element where its power
dissipation might be a remarkable fraction of the total power
demand of an electrolysis system. Power dissipation in a
semiconductor switching element is related to many different
parameters which could be fitted into two main categories:
switching losses and conduction losses. Conduction losses are
directly related to the built, structure and capabilities of a
switching device itself and indeed the conditions in which the
element is handling the switching application such as voltage,
current, temperature and of course the fabrication technology.
On the other hand, switching losses have some other
influencing variables other than the mentioned such as control
system, switching method and power electronics circuitry of
the PWM power driver. By analyzings the characteristics of
recently developed power switching transistors from different
families of Bipolar Junction Transistors (BJT), Metal Oxide
Semiconductor Field Effect Transistors (MOSFET) and
Insulated Gate Bipolar Transistors (IGBT), some
recommendations are made in this paper which are able to
lead to achieve higher hydrogen production efficiency by
utilizing PWM controlled water electrolysis cells.
Abstract: In this paper, perceptions of actors on changes in
crop productivity, quantity and quality of water, and determinants of
their perception are analyzed using descriptive statistics and ordered
logit model. Data collected from 297 Ethiopian farmers and 103
agricultural professionals from December 2009 to January 2010 are
employed. Results show that the majority of the farmers and
professionals recognized decline in water resources, reasoning
climate changes and soil erosion as some of the causes. However,
there is a variation in views on changes in productivity. The
household asset, education level, age and geographical positions are
found to affect farmers- perception on changes in crop productivity.
But, the study underlines that there is no evidence that farmers-
economic status, age, or education level affects recognition of
degradation of water resources. Thus, more focus shall be given on
providing them different coping mechanisms and alternative
resource conserving technologies than educating about the
problems.
Abstract: Space-time block codes (STBC) and spatial multiplexing
(SM) are promising techniques that effectively exploit multipleinput
multiple-output (MIMO) transmission to achieve more reliable
communication and a higher multiplexing rate, respectively. In this
paper, we study a practical design for hybrid scheme with multi-input
multi-output orthogonal frequency division multiplexing (MIMOOFDM)
systems to flexibly maximize the tradeoff between diversity
and multiplexing gains. Unlike the existing STBC and SM designs
which are suitable for the integer multiplexing rate, the proposed
design can achieve arbitrary number of multiplexing rate.
Abstract: A real time image-guided electroplating system is
proposed in this paper. Unlike previous electroplating systems, instead
of using the intermittent mode to electroplate 500um long copper
specimen, a CCD camera and a motion controller are used to adjust
anode-cathode distance to obtain better results. Since the image of the
gap distance is highly deteriorated due to complex chemical-electrical
operation inside the electrolyte, to determine the gap distance, an
image processing algorithm is developed and mainly based on the
entropy and energy values. In addition, the color and incidence
direction of light source are also discussed to help the image process in
this paper. From the experiment results, the specimens created by the
proposed system show better structure, better uniformity and better
finishing surface compared to those by previous intermittent
electroplating setup.
Abstract: In this paper we present an extension to Vision Based
LRTA* (VLRTA*) known as Vision Based Moving Target Search
(VMTS) for capturing unknown moving target in unknown territory
with randomly generated obstacles. Target position is unknown to the
agents and they cannot predict its position using any probability
method. Agents have omni directional vision but can see in one
direction at some point in time. Agent-s vision will be blocked by the
obstacles in the search space so agent can not see through the
obstacles. Proposed algorithm is evaluated on large number of
scenarios. Scenarios include grids of sizes from 10x10 to 100x100.
Grids had obstacles randomly placed, occupying 0% to 50%, in
increments of 10%, of the search space. Experiments used 2 to 9
agents for each randomly generated maze with same obstacle ratio.
Observed results suggests that VMTS is effective in locate target
time, solution quality and virtual target. In addition, VMTS becomes
more efficient if the number of agents is increased with proportion to
obstacle ratio.
Abstract: Pharmacology curriculum plays an integral role in
medical education. Learning pharmacology to choose and prescribe
drugs is a major challenge encountered by students. We developed
pharmacology applied learning activities for first year medical
students that included realistic clinical situations with escalating
complications which required the students to analyze the situation
and think critically to choose a safe drug. Tutor feedback was
provided at the end of session. Evaluation was done to assess the
students- level of interest and usefulness of the sessions in rational
selection of drugs. Majority (98 %) of the students agreed that the
session was an extremely useful learning exercise and agreed that
similar sessions would help in rational selection of drugs. Applied
learning sessions in the early years of medical program may promote
deep learning and bridge the gap between pharmacology theory and
clinical practice. Besides, it may also enhance safe prescribing skills.
Abstract: In intensity modulated radiation therapy (IMRT)
treatment planning, beam angles are usually preselected on the basis of
experience and intuition. Therefore, getting an appropriate beam
configuration needs a very long time. Based on the present situation,
the paper puts forward beam orientation optimization using ant colony
optimization (ACO). We use ant colony optimization to select the
beam configurations, after getting the beam configuration using
Conjugate Gradient (CG) algorithm to optimize the intensity profiles.
Combining with the information of the effect of pencil beam, we can
get the global optimal solution accelerating. In order to verify the
feasibility of the presented method, a simulated and clinical case was
tested, compared with dose-volume histogram and isodose line
between target area and organ at risk. The results showed that the
effect was improved after optimizing beam configurations. The
optimization approach could make treatment planning meet clinical
requirements more efficiently, so it had extensive application
perspective.
Abstract: The massive proliferation of affordable computers, Internet broadband connectivity and rich education content has created a global phenomenon in which information and communication technology (ICT) is being used to transform education. Therefore, there is a need to redesign the educational system to meet the needs better. The advent of computers with sophisticated software has made it possible to solve many complex problems very fast and at a lower cost. This paper introduces the characteristics of the current E-Learning and then analyses the concept of cloud computing and describes the architecture of cloud computing platform by combining the features of E-Learning. The authors have tried to introduce cloud computing to e-learning, build an e-learning cloud, and make an active research and exploration for it from the following aspects: architecture, construction method and external interface with the model.
Abstract: With the widespread growth of applications of
Wireless Sensor Networks (WSNs), the need for reliable security
mechanisms these networks has increased manifold. Many security
solutions have been proposed in the domain of WSN so far. These
solutions are usually based on well-known cryptographic
algorithms.
In this paper, we have made an effort to survey well known
security issues in WSNs and study the behavior of WSN nodes that
perform public key cryptographic operations. We evaluate time
and power consumption of public key cryptography algorithm for
signature and key management by simulation.
Abstract: Computer worm detection is commonly performed by
antivirus software tools that rely on prior explicit knowledge of the
worm-s code (detection based on code signatures). We present an
approach for detection of the presence of computer worms based on
Artificial Neural Networks (ANN) using the computer's behavioral
measures. Identification of significant features, which describe the
activity of a worm within a host, is commonly acquired from security
experts. We suggest acquiring these features by applying feature
selection methods. We compare three different feature selection
techniques for the dimensionality reduction and identification of the
most prominent features to capture efficiently the computer behavior
in the context of worm activity. Additionally, we explore three
different temporal representation techniques for the most prominent
features. In order to evaluate the different techniques, several
computers were infected with five different worms and 323 different
features of the infected computers were measured. We evaluated
each technique by preprocessing the dataset according to each one
and training the ANN model with the preprocessed data. We then
evaluated the ability of the model to detect the presence of a new
computer worm, in particular, during heavy user activity on the
infected computers.
Abstract: This paper is to present context-aware sensor grid
framework for agriculture and its design challenges. Use of sensor
networks in the domain of agriculture is not new. However, due to
the unavailability of any common framework, solutions that are
developed in this domain are location, environment and problem
dependent. Keeping the need of common framework for agriculture,
Context-Aware Sensor Grid Framework is proposed. It will be
helpful in developing solutions for majority of the problems related
to irrigation, pesticides spray, use of fertilizers, regular monitoring of
plot and yield etc. due to the capability of adjusting according to
location and environment. The proposed framework is composed of
three layer architecture including context-aware application layer,
grid middleware layer and sensor network layer.
Abstract: Sensors possess several properties of physical
measures. Whether devices that convert a sensed signal into an
electrical signal, chemical sensors and biosensors, thus all these
sensors can be considered as an interface between the physical and
electrical equipment. The problem is the analysis of the multitudes of
saved settings as input variables. However, they do not all have the
same level of influence on the outputs. In order to identify the most
sensitive parameters, those that can guide users in gathering
information on the ground and in the process of model calibration
and sensitivity analysis for the effect of each change made.
Mathematical models used for processing become very complex.
In this paper a fuzzy rule-based system is proposed as a solution
for this problem. The system collects the available signals
information from sensors. Moreover, the system allows the study of
the influence of the various factors that take part in the decision
system. Since its inception fuzzy set theory has been regarded as a
formalism suitable to deal with the imprecision intrinsic to many
problems. At the same time, fuzzy sets allow to use symbolic models.
In this study an example was applied for resolving variety of
physiological parameters that define human health state. The
application system was done for medical diagnosis help. The inputs
are the signals expressed the cardiovascular system parameters, blood
pressure, Respiratory system paramsystem was done, it will be able
to predict the state of patient according any input values.
Abstract: The blood ducts must be occluded to avoid loss of
blood from vessels in laparoscopic surgeries. This paper presents a
locking mechanism to be used in a ligation laparoscopic procedure
(LigLAP I), as an alternative solution for a stapling procedure.
Currently, stapling devices are being used to occlude vessels. Using
these devices may result in some problems, including injury of bile
duct, taking up a great deal of space behind the vessel, and bile leak.
In this new procedure, a two-layer suture occludes a vessel. A
locking mechanism is also required to hold the suture. Since there is
a limited space at the device tip, a Shape Memory Alloy (SMA)
actuator is used in this mechanism. Suitability for cleanroom
applications, small size, and silent performance are among the
advantages of SMA actuators in biomedical applications. An
experimental study is conducted to examine the function of the
locking mechanism. To set up the experiment, a prototype of a
locking mechanism is built using nitinol, which is a nickel-titanium
shape memory alloy. The locking mechanism successfully locks a
polymer suture for all runs of the experiment. In addition, the effects
of various surface materials on the applied pulling forces are studied.
Various materials are mounted at the mechanism tip to compare the
maximum pulling forces applied to the suture for each material. The
results show that the various surface materials on the device tip
provide large differences in the applied pulling forces.
Abstract: The effect of varying holding temperature on hatching success, occurrence of deformities and mortality rates were investigated for goldlined seabream eggs. Wild broodstock (600 g) were stocked at a 2:1 male-female ratio in a 2 m3 fiberglass tank supplied with filtered seawater (37 g L-1 salinity, temp. range 24±0.5 oC [day] and 22±1 oC [night], DO2 in excess of 5.0mg L-1). Females were injected with 200 IU kg-1 HCG between 08.00 and 10.00 h and returned to tanks to spawn following which eggs were collected by hand using a 100μm net. Fertilized eggs at the gastrulation stage (120 L-1) were randomly placed into one of 12 experimental 6 L aerated (DO2 5 mg L-1) plastic containers with water temperatures maintained at 24±0.5 oC (ambient), 26±0.5 oC, 28± 0.5 oC and 30±0.5 oC using thermostats. Each treatment was undertaken in triplicate using a 12:12 photophase:scotophase photoperiod. No differences were recorded between eggs reared at 24 and 26 oC with respect to viability, deformity, mortality or unhatched egg rates. Increasing temperature reduced the number of viable eggs with those at 30 oC returning poorest performance (P < 0.05). Mortality levels were lowest for eggs incubated at 24 and 26 oC. The greatest level of deformities recorded was that for eggs reared at 28 oC.
Abstract: Silicon is a beneficial element for plant growth. It
helps plants to overcome multiple stresses, alleviates metal toxicity
and improves nutrient imbalance. Field experiment was conducted as
split-split plot arranged in a randomized complete block design with
four replications. Irrigation system include continues flooding and
deficit as main plots and nitrogen rates N0, N46, N92, and N138 kg/ha
as sub plots and silicon rates Si0 & Si500 kg/ha as sub-subplots.
Results indicate that grain yield had not significant difference
between irrigation systems. Flooding irrigation had higher biological
yield than deficit irrigation whereas, no significant difference in grain
and straw yield. Nitrogen application increased grain, biological and
straw yield. Silicon application increased grain, biological and straw
yield but, decreased harvest index. Flooding irrigation had higher
number of total tillers / hill than deficit irrigation, but deficit
irrigation had higher number of fertile tillers / hill than flooding
irrigation. Silicon increased number of filled spikelet and decreased
blank spikelet. With high nitrogen application decreased 1000-grain
weight. It can be concluded that if the nitrogen application was high
and water supplied was available we could have silicon application
until increase grain yield.
Abstract: In this study, a low temperature sensor highly selective to CO in presence of methane is fabricated by using 4 nm SnO2 quantum dots (QDs) prepared by sonication assisted precipitation. SnCl4 aqueous solution was precipitated by ammonia under sonication, which continued for 2 h. A part of the sample was then dried and calcined at 400°C for 1.5 h and characterized by XRD and BET. The average particle size and the specific surface area of the SnO2 QDs as well as their sensing properties were compared with the SnO2 nano-particles which were prepared by conventional sol-gel method. The BET surface area of sonochemically as-prepared product and the one calcined at 400°C after 1.5 hr are 257 m2/gr and 212 m2/gr respectively while the specific surface area for SnO2 nanoparticles prepared by conventional sol-gel method is about 80m2/gr. XRD spectra revealed pure crystalline phase of SnO2 is formed for both as-prepared and calcined samples of SnO2 QDs. However, for the sample prepared by sol-gel method and calcined at 400°C SnO crystals are detected along with those of SnO2. Quantum dots of SnO2 show exceedingly high sensitivity to CO with different concentrations of 100, 300 and 1000 ppm in whole range of temperature (25- 350°C). At 50°C a sensitivity of 27 was obtained for 1000 ppm CO, which increases to a maximum of 147 when the temperature rises to 225°C and then drops off while the maximum sensitivity for the SnO2 sample prepared by the sol-gel method was obtained at 300°C with the amount of 47.2. At the same time no sensitivity to methane is observed in whole range of temperatures for SnO2 QDs. The response and recovery times of the sensor sharply decreases with temperature, while the high selectivity to CO does not deteriorate.
Abstract: The great challenge of the agricultural sector is to
produce more crop from less water, which can be achieved by
increasing crop water productivity. The modernization of the
irrigation systems offers a number of possibilities to expand the
economic productivity of water and improve the virtual water status.
The objective of the present study is to assess the global water
productivity (GWP) within the major irrigation command areas of
I.R. Iran. For this purpose, fourteen irrigation command areas where
located in different areas of Iran were selected. In order to calculate
the global water productivity of irrigation command areas, all data on
the delivered water to cropping pattern, cultivated area, crops water
requirement, and yield production rate during 2002-2006 were
gathered. In each of the command areas it seems that the cultivated
crops have a higher amount of virtual water and thus can be replaced
by crops with less virtual water. This is merely suggested due to crop
water consumption and at the time of replacing crops, economic
value as well as cultural and political factors must be considered. The
results indicated that the lowest GWP belongs to Mahyar and
Borkhar irrigation areas, 0.24 kg m-3, and the highest is that of the
Dez irrigation area, 0.81 kg m-3. The findings demonstrated that
water management in the two irrigation areas is just efficient. The
difference in the GWP of irrigation areas is due to variations in the
cropping pattern, amount of crop productions, in addition to the
effective factors in the water use efficiency in the irrigation areas.