Abstract: This paper proves that the problem of finding connected
vertex cover in a 2-connected planar graph ( CVC-2 ) with maximum degree 4 is NP-complete. The motivation for proving this result is to
give a shorter and simpler proof of NP-Completeness of TRA-MLC (the Top Right Access point Minimum-Length Corridor) problem [1], by finding the reduction from CVC-2. TRA-MLC has many applications in laying optical fibre cables for data communication and electrical wiring in floor plans.The problem of finding connected vertex cover in any planar graph ( CVC ) with maximum degree 4 is NP-complete [2]. We first show that CVC-2 belongs to NP and then we find a polynomial reduction from CVC to CVC-2. Let a graph G0 and an integer K form an instance of CVC, where G0 is a planar graph and K is an upper bound on the size of the connected vertex cover in G0. We construct a 2-connected planar graph, say G, by identifying the blocks and cut vertices of G0, and then finding the planar representation of all the blocks of G0, leading to a plane graph G1. We replace the cut vertices with cycles in such a way that the resultant graph G is a 2-connected planar graph with maximum
degree 4. We consider L = K -2t+3 t i=1 di where t is the number of cut vertices in G1 and di is the number of blocks for which ith cut vertex is common. We prove that G will have a connected vertex
cover with size less than or equal to L if and only if G0 has a connected vertex cover of size less than or equal to K.
Abstract: We examined whether children ( < 18 years old) had risk of intra-thoracic trauma during 'one-handed' chest compressions through MDCT images. We measured the length of the lower half of the sternum (Stotal/2~X). We also measured the distance from the diaphragm to the midpoint of the sternum (Stotal/2~D) and half the width of an adult hand (Wtotal/2). All the 1 year-old children had Stotal/2~X and Stotal/2~D less than Wtotal/2. Among the children aged 2 years, 6 (60.0%) had Stotal/2~X and Stotal/2~D less than Wtotal/2. Among those aged 3 years, 4 (26.7%) had Stotal/2~X and Stotal/2~D less than Wtotal/2, and among those aged 4 years, 2 (13.3%) had Stotal/2~X and Stotal/2~D less than Wtotal/2. However, Stotal/2~X and Stotal/2~D were greater than Wtotal/2 in children aged 5 years or more. We knew that small children may be at an increased risk of intra-thoracic trauma during 'one-handed' chest compressions.
Abstract: This paper treats a discrete-time batch arrival queue with single working vacation. The main purpose of this paper is to present a performance analysis of this system by using the supplementary variable technique. For this purpose, we first analyze the Markov chain underlying the queueing system and obtain its ergodicity condition. Next, we present the stationary distributions of the system length as well as some performance measures at random epochs by using the supplementary variable method. Thirdly, still based on the supplementary variable method we give the probability generating function (PGF) of the number of customers at the beginning of a busy period and give a stochastic decomposition formulae for the PGF of the stationary system length at the departure epochs. Additionally, we investigate the relation between our discretetime system and its continuous counterpart. Finally, some numerical examples show the influence of the parameters on some crucial performance characteristics of the system.
Abstract: For many industrial applications plate heat
exchangers are demonstrating a large superiority over the
other types of heat exchangers. The efficiency of such a
device depends on numerous factors the effect of which needs
to be analysed and accurately evaluated.
In this paper we present a theoretical analysis of a cocurrent
plate heat exchanger and the results of its numerical
simulation.
Knowing the hot and the cold fluid streams inlet temperatures,
the respective heat capacities mCp
and the value of the
overall heat transfer coefficient, a 1-D mathematical model
based on the steady flow energy balance for a differential
length of the device is developed resulting in a set of N first
order differential equations with boundary conditions where N
is the number of channels.For specific heat exchanger
geometry and operational parameters, the problem is
numerically solved using the shooting method.
The simulation allows the prediction of the temperature
map in the heat exchanger and hence, the evaluation of its
performances. A parametric analysis is performed to evaluate
the influence of the R-parameter on the e-NTU values. For
practical purposes effectiveness-NTU graphs are elaborated
for specific heat exchanger geometry and different operating
conditions.
Abstract: The effect of muscle loss due to transfemoral
amputation, on energy expenditure of hip joint and individual
residual muscles was simulated. During swing phase of gait, with
each muscle as an ideal force generator, the lower extremity was
modeled as a two-degree of freedom linkage, for which hip and knee
were joints. According to results, muscle loss will not lead to higher
energy expenditure of hip joint, as long as other parameters of limb
remain unaffected. This finding maybe due to the role of biarticular
muscles in hip and knee joints motion. Moreover, if hip flexors are
removed from the residual limb, residual flexors, and if hip extensors
are removed, residual extensors will do more work. In line with the
common practice in transfemoral amputation, this result demonstrates
during transfemoral amputation, it is important to maintain the length
of residual limb as much as possible.
Abstract: Evolution of one-dimensional electron system under
high-energy-density (HED) conditions is investigated, using the
principle of least-action and variational method. In a single-mode
modulation model, the amplitude and spatial wavelength of the
modulation are chosen to be general coordinates. Equations of motion
are derived by considering energy conservation and force balance.
Numerical results show that under HED conditions, electron density
modulation could exist. Time dependences of amplitude and
wavelength are both positively related to the rate of energy input.
Besides, initial loading speed has a significant effect on modulation
amplitude, while wavelength relies more on loading duration.
Abstract: In the domain of machine vision, the
measurement of length is done using cameras where the
accuracy is directly proportional to the resolution of the
camera and inversely to the size of the object. Since most of
the pixels are wasted imaging the entire body as opposed to
just imaging the edges in a conventional system, a double
aperture system is constructed to focus on the edges to
measure at higher resolution. The paper discusses the
complexities and how they are mitigated to realize a practical
machine vision system.
Abstract: In this study, we are interested in the economic lot
scheduling problem (ELSP) that considers manufacturing of the
serviceable products and remanufacturing of the reworked products. In
this paper, we formulate a mathematical model for the ELSP with
reworks using the basic period approach. In order to solve this
problem, we propose a search algorithm to find the cyclic multiplier ki
of each product that can be cyclically produced for every ki basic
periods. This research also uses two heuristics to search for the optimal
production sequence of all lots and the optimal time length of the basic
period so as to minimize the average total cost. This research uses a
numerical example to show the effectiveness of our approach.
Abstract: The vehicle fleet of public transportation companies is often equipped with intelligent on-board passenger information systems. A frequently used but time and labor-intensive way for keeping the on-board controllers up-to-date is the manual update using different memory cards (e.g. flash cards) or portable computers. This paper describes a compression algorithm that enables data transmission using low bandwidth wireless radio networks (e.g. GPRS) by minimizing the amount of data traffic. In typical cases it reaches a compression rate of an order of magnitude better than that of the general purpose compressors. Compressed data can be easily expanded by the low-performance controllers, too.
Abstract: The development of biomimetic micro-aerial-vehicles
(MAVs) with flapping wings is the future trend in military/domestic
field. The successful flight of MAVs is strongly related to the
understanding of unsteady aerodynamic performance of low Reynolds
number airfoils under dynamic flapping motion. This study explored
the effects of flapping frequency, stroke amplitude, and the inclined
angle of stroke plane on lift force and thrust force of a bio-inspiration
corrugated airfoil with 33 full factorial design of experiment and
ANOVA analysis. Unsteady vorticity flows over a corrugated thin
airfoil executing flapping motion are computed with time-dependent
two-dimensional laminar incompressible Reynolds-averaged
Navier-Stokes equations with the conformal hybrid mesh. The tested
freestream Reynolds number based on the chord length of airfoil as
characteristic length is fixed of 103. The dynamic mesh technique is
applied to model the flapping motion of a corrugated airfoil. Instant
vorticity contours over a complete flapping cycle clearly reveals the
flow mechanisms for lift force generation are dynamic stall, rotational
circulation, and wake capture. The thrust force is produced as the
leading edge vortex shedding from the trailing edge of airfoil to form a
reverse von Karman vortex. Results also indicated that the inclined
angle is the most significant factor on both the lift force and thrust
force. There are strong interactions between tested factors which mean
an optimization study on parameters should be conducted in further
runs.
Abstract: Geometric design is an important part of planning
process design for physical highway to fill up basic function of roads,
to give good traffic service. It is found that most of the road safety
problems occur at the horizontal curves and complex-compound
curves. In this paper, review on Sagarinn-Myinsain Portion of Nay
Pyi Taw - Mandalay highway has been conducted in aspect of
geometric design induced road safety condition. Horizontal
alignment of geometric features and curve details are reviewed based
on (AASHTO) standard and revised by Autodesk Land Desktop
Software. Moreover, 85th Percentile Operation Speeds (V85) with
driver confidence on horizontal curves is evaluated in order to obtain
the range of highway safety factor (FS). The length of the selected
highway portion is 13.65 miles and 8 lanes. The results of this study
can be used to investigate the possible hazardous locations in
advance and to revise how design radius and super elevation should
be for better road safety performance for the selected portion.
Moreover, the relationship between highway safety and highway
geometry characteristics can also be known.
Abstract: Evaluation of crop plants resistance to environmental
stresses specially in germination stage is a critical factor in their
selection in different conditions of cultivation. Therefore use of a
procedure in controllable situation can help to evaluate plants
reaction to stress quickly and precisely. In order to study germination
characteristics of flax in water and salinity stress conditions were
conducted two laboratories experimental. The two experimental were
conducted in 4-replicant completing random design for salinity and
water stress. The treatment, for salinity and water stress was three
potential (zero, 40, 80 mM) of NaCl and three potential (zero, -2, -4
bar) of PEG respectively. Germination percentage and rate, in
addition to Radical and plumule length and dry-weight and
plumule/Radical ration were measured. All of characteristics reduce
under water stress conditions. salinity stress significant reduce
germination rate and Radical and plumule length of flax seeds.
Hydropriming and osmopriming significant increased germination
rate, plumule length and plumule/Radical ration ration of flax seeds.
But germination percentage and Radical and plumule dry weight
significant increased only in hydropriming treat. Hydropriming and
osmopriming could not be used to improved germination under saline
and drought stress. But has more tolerance in salinity and drought
stress in flax by less reduce in Radical and plumule length under
saline and drought stress.
Abstract: In this paper, the link quality in SHF and EHF ranges
are studied. In order to achieve high data rate higher frequencies must
be used – centimeter waves (SHF), millimeter waves (EHF) or optical
range. However, there are significant problem when a radio link work
in that diapason – rain attenuation and attenuation in earth-s
atmosphere. Based on statistical rain rates data for Bulgaria, the link
availability can be determined, depending on the working frequency,
the path length and the Power Budget of the link. For the calculations
of rain attenuation and atmosphere-s attenuation the ITU
recommendations are used.
Abstract: The increments of aromatic structures are widely used to monitor the degree of humification. Compost derived from mix manures mixed with agricultural wastes was studied. The compost collected at day 0, 7, 14, 21, 28, 35, 49, 77, 91, 105, and 119 was divided into 3 stages, initial stage at day 0, thermophilic stage during day 1-48, and mature stage during day 49-119. The change of highest absorptions at wavelength range between 210-235 nm during day 0- 49 implied that small molecules such as nitrates and carboxylic occurred faster than the aromatic molecules that were found at wavelength around 280 nm. The ratio of electron-transfer band at wavelength 253 nm by the benzonoid band at wavelength 230 nm (E253/E230) also gradually increased during the fermenting period indicating the presence of O-containing functional groups. This was in agreement with the shift change from aliphatic to aromatic structures as shown by the relationship with C/N and H/C ratios (r = - 0.631 and -0.717, p< 0.05) since both were decreasing. Although the amounts of humic acid (HA) were not different much during the humification process, the UV spectral deconvolution showed better qualitative characteristics to help in determining the compost quality. From this study, the compost should be used at day 49 and should not be kept longer than 3 months otherwise the quality of HA would decline regardless of the amounts of HA that might be rising. This implied that other processes, such as mineralization had an influence on the humification process changing HA-s structure and its qualities.
Abstract: Downward turbulent bubbly flows in pipes were
modeled using computational fluid dynamics tools. The
Hydrodynamics, phase distribution and turbulent structure of twophase
air-water flow in a 57.15 mm diameter and 3.06 m length
vertical pipe was modeled by using the 3-D Eulerian-Eulerian
multiphase flow approach. Void fraction, liquid velocity and
turbulent fluctuations profiles were calculated and compared against
experimental data. CFD results are in good agreement with
experimental data.
Abstract: Traditional optical networks are gradually evolving towards intelligent optical networks due to the need for faster bandwidth provisioning, protection and restoration of the network that can be accomplished with devices like optical switch, add drop multiplexer and cross connects. Since dense wavelength multiplexing forms the physical layer for intelligent optical networking, the roll of high speed all optical switch is important. This paper analyzes such an ultra-high speed polymer electro-optic switch. The performances of the 2x2 optical waveguide switch with rectangular, triangular and trapezoidal grating profiles on various device parameters are analyzed. The simulation result shows that trapezoidal grating is the optimized structure which has the coupling length of 81μm and switching voltage of 11V for the operating wavelength of 1550nm. The switching time for this proposed switch is 0.47 picosecond. This makes the proposed switch to be an important element in the intelligent optical network.
Abstract: A simple approach is demonstrated for growing large
scale, nearly vertically aligned ZnO nanowire arrays by thermal
oxidation method. To reveal effect of temperature on growth and
physical properties of the ZnO nanowires, gold coated zinc substrates
were annealed at 300 °C and 400 °C for 4 hours duration in air. Xray
diffraction patterns of annealed samples indicated a set of well
defined diffraction peaks, indexed to the wurtzite hexagonal phase of
ZnO. The scanning electron microscopy studies show formation of
ZnO nanowires having length of several microns and average of
diameter less than 500 nm. It is found that the areal density of wires
is relatively higher, when the annealing is carried out at higher
temperature i.e. at 400°C. From the field emission studies, the values
of the turn-on and threshold field, required to draw emission current
density of 10 μA/cm2 and 100 μA/cm2 are observed to be 1.2 V/μm
and 1.7 V/μm for the samples annealed at 300 °C and 2.9 V/μm and
3.7 V/μm for that annealed at 400 °C, respectively. The field
emission current stability, investigated over duration of more than 2
hours at the preset value of 1 μA, is found to be fairly good in both
cases. The simplicity of the synthesis route coupled with the
promising field emission properties offer unprecedented advantage
for the use of ZnO field emitters for high current density
applications.
Abstract: Channel junctions can be analyzed in two ways of
division (lateral intake) and combined flows (confluence). The
present paper investigates 3D flow pattern at lateral intake using
Navier-Stokes equation and κ -ε (RNG) turbulent model. The
equations are solved by Finite-Volume Method (FVM) and results
are compared with the experimental data of (Barkdoll, B.D., 1997)
to test the validity of the findings. Comparison of the results with
the experimental data indicated a close proximity between the two
sets of data which suggest a very close simulation. Results further
indicated an inverse relation between the effects of discharge ratio
( r Q ) on the length and width of the separation zone. In other words,
as the discharge ration increases, the length and width of separation
zone decreases.
Abstract: In order to study seed yield and seed yield
components in bean under reduced irrigation condition and
assessment drought tolerance of genotypes, 15 lines of White beans
were evaluated in two separate RCB design with 3 replications under
stress and non stress conditions. Analysis of variance showed that
there were significant differences among varieties in terms of traits
under study, indicating the existence of genetic variation among
varieties. The results indicate that drought stress reduced seed yield,
number of seed per plant, biological yield and number of pod in
White been. In non stress condition, yield was highly correlated with
the biological yield, whereas in stress condition it was highly
correlated with harvest index. Results of stepwise regression showed
that, selection can we done based on, biological yield, harvest index,
number of seed per pod, seed length, 100 seed weight. Result of path
analysis showed that the highest direct effect, being positive, was
related to biological yield in non stress and to harvest index in stress
conditions. Factor analysis were accomplished in stress and nonstress
condition a, there were 4 factors that explained more than 76
percent of total variations. We used several selection indices such as
Stress Susceptibility Index ( SSI ), Geometric Mean Productivity (
GMP ), Mean Productivity ( MP ), Stress Tolerance Index ( STI ) and
Tolerance Index ( TOL ) to study drought tolerance of genotypes, we
found that the best Stress Index for selection tolerance genotypes
were STI, GMP and MP were the greatest correlations between these
Indices and seed yield under stress and non stress conditions. In
classification of genotypes base on phenotypic characteristics, using
cluster analysis ( UPGMA ), all allels classified in 5 separate groups
in stress and non stress conditions.
Abstract: In present paper we proposed a simple and effective method to compress an image. Here we found success in size reduction of an image without much compromising with it-s quality. Here we used Haar Wavelet Transform to transform our original image and after quantization and thresholding of DWT coefficients Run length coding and Huffman coding schemes have been used to encode the image. DWT is base for quite populate JPEG 2000 technique.