Abstract: The application of the synchronous dynamic random
access memory (SDRAM) has gone beyond the scope of personal
computers for quite a long time. It comes into hand whenever a big
amount of low price and still high speed memory is needed. Most of
the newly developed stand alone embedded devices in the field of
image, video and sound processing take more and more use of it. The
big amount of low price memory has its trade off – the speed. In
order to take use of the full potential of the memory, an efficient
controller is needed. Efficient stands for maximum random accesses
to the memory both for reading and writing and less area after
implementation. This paper proposes a target device independent
DDR SDRAM pipelined controller and provides performance
comparison with available solutions.
Abstract: In this work we report on preliminary analysis of a novel optoelectronic gas sensor based on an optical fiber integrated with a tetrakis(4-sulfonatophenyl)porphyrin (TPPS) thin film. The sensitive materials are selectively deposited on the core region of a fiber tip by UV light induced deposition technique. A simple and cheap process which can be easily extended to different porphyrin derivatives. When the TPPS film on the fiber tip is exposed to acid and/or base vapors, dramatic changes occur in the aggregation structure of the dye molecules in the film, from J- to H-type, resulting in a profound modification of their corresponding reflectance spectra. From the achieved experimental results it is evident that the presence of intense and narrow band peaks in the reflected spectra could be monitored to detect hazardous vapors.
Abstract: The results of an experimental study of the process of
convective and boiling heat transfer in the vessel with stirrer for
smooth and rough ring-shaped pipes are presented. It is established
that creation of two-dimensional artificial roughness on the heated
surface causes the essential (~100%) intensification of convective
heat transfer. In case of boiling the influence of roughness appears on
the initial stage of boiling and in case of fully developed nucleate
boiling there was no intensification of heat transfer. The similitude
equation for calculating convective heat transfer coefficient, which
generalizes well experimental data both for the smooth and the rough
surfaces is proposed.
Abstract: Electricity market activities and a growing demand for electricity have led to heavily stressed power systems. This requires operation of the networks closer to their stability limits. Power system operation is affected by stability related problems, leading to unpredictable system behavior. Voltage stability refers to the ability of a power system to sustain appropriate voltage levels through large and small disturbances. Steady-state voltage stability is concerned with limits on the existence of steady-state operating points for the network. FACTS devices can be utilized to increase the transmission capacity, the stability margin and dynamic behavior or serve to ensure improved power quality. Their main capabilities are reactive power compensation, voltage control and power flow control. Among the FACTS controllers, Static Var Compensator (SVC) provides fast acting dynamic reactive compensation for voltage support during contingency events. In this paper, voltage stability assessment with appropriate representations of tap-changer transformers and SVC is investigated. Integrating both of these devices is the main topic of this paper. Effect of the presence of tap-changing transformers on static VAR compensator controller parameters and ratings necessary to stabilize load voltages at certain values are highlighted. The interrelation between transformer off nominal tap ratios and the SVC controller gains and droop slopes and the SVC rating are found. P-V curves are constructed to calculate loadability margins.
Abstract: A modified Saleh-Valenzuela channel model has been
adapted for Ultra Wideband (UWB) system. The suggested realistic
channel is assessed by its distribution of fading amplitude and time of
arrivals. Furthermore, the propagation characteristic has been distinct
into four channel models, namely CM 1 to 4. Each are differentiate in
terms of cluster arrival rates, rays arrival rate within each cluster and
its respective constant decay rates. This paper described the
multiband OFDM system performance simulates under these
multipath conditions. Simulation work described in this paper is
based on WiMedia ECMA-368 standard, which has been deployed
for practical implementation of low cost and low power UWB
devices.
Abstract: A variational method is used to obtain the growth rate of a transverse long-wavelength perturbation applied to the soliton solution of a nonlinear Schr¨odinger equation with a three-half order potential. We demonstrate numerically that this unstable perturbed soliton will eventually transform into a cylindrical soliton.
Abstract: Compaction testing methods allow at-speed detecting
of errors while possessing low cost of implementation. Owing to this
distinctive feature, compaction methods have been widely used for
built-in testing, as well as external testing. In the latter case, the
bandwidth requirements to the automated test equipment employed
are relaxed which reduces the overall cost of testing. Concurrent
compaction testing methods use operational signals to detect
misbehavior of the device under test and do not require input test
stimuli. These methods have been employed for digital systems only.
In the present work, we extend the use of compaction methods for
concurrent testing of analog-to-digital converters. We estimate
tolerance bounds for the result of compaction and evaluate the
aliasing rate.
Abstract: Due to the Rapid Urbanization in China, the influence of metropolises to surrounding areas grows by a tremendous speed in developed region. One of the most obvious influences is the expansion of the urban built-up areas which covers the land belongs to small towns. Around metropolitan fringe, the boundary between city and village becomes more and more obscure. So being the most sensitive area, the small towns on the fringe of metropolises have the special meaning on the research into the small towns- development. This paper chooses Sandun Town in Hangzhou of Zhejiang Province as an example, emphatically focus on aspects such as the central area proliferation, the industrial shift, the position effect, the subway effect and the commercial development, reviews a few problems of small towns in the future and the important problems in their planning by the analysis of the characteristics of the present conditions and the developing motive mechanism, so that guides small towns to develop properly by liking with these small towns and center metropolises.
Abstract: Porcine production in China represents approximately
the 50% of the worldwide pig production. Information about pig
husbandry characteristics in China and manure properties from sows
to fatteners in intensive pig farms are not broadly available for
scientific studies as it is a time consuming, expensive task and highly
inaccessible. This study provides a report about solid pig manures
(28% dry matter) in a commercial pig farm located in the peri-urban
area of Beijing as well as a general overview of the current pig
husbandry techniques including pig breeds, feeds, diseases, housing as
well as pig manure and wastewater disposal. The main results are
intended to serve as a literature source for young scientists in order to
understand the main composition of pig manures as well as to identify
the husbandry techniques applied in an intensive pig farm in Beijing.
Abstract: This paper examines the role and the place of
transdisciplinarity in the urbanism of the 21st century, with the
emphasis on Montenegro urbanism. Global processes require a
systematic strategy and systemic synergistic engagement in the
development of cities in 21st centuries. Urbanism as a profession and
a discipline should be developed parallel and in correlation, based on
the principles of integrality and communication skills, in order to
enable development of the sustainable urban system. The importance
of integrated urbanism and other disciplines are also emphasized as
well as their synergies activities. The paper also presents the positive
examples of urban theory and practice in the world, which influenced
the direction of development of the modern urbanism.
Transdisciplinarity is a priority methodology for sustainable urban
development, which is insufficiently developed in Montenegro, but
there is a basis for its development. It is necessary to unite different
social sensibilities, academic and non-academic knowledge, as well
as the public and private sectors in order to develop holistic,
inclusive and sustainable urban spaces of the 21st centuries.
Abstract: As a result of the high cost of housing, the increasing population is forced to live in substandard housing and unhealthy conditions giving rise to poor residential neighborhoods. The paper examines the causes and characteristics of poor residential neighborhood. The paper finds the problems that have influence poor neighborhoods to; poverty, growth of informal sector and housing shortage. The paper asserts that poor residential neighborhoods have adverse effects on the people.
The secondary data was obtained from books, journals and seminar papers while primary data relating to building and environmental quality from structured questionnaire administered on sample of 500 household heads, from sampling frame of 5000 housing units.
The study reveals that majority of the respondents are poor and employed in informal sector. The paper suggests urban renewal and slum upgrading programs as methods in dealing with the situation and an improvement in the socio-economic circumstances of the inhabitants.
Abstract: Ethnicity identification of face images is of interest in
many areas of application, but existing methods are few and limited.
This paper presents a fusion scheme that uses block-based uniform
local binary patterns and Haar wavelet transform to combine local
and global features. In particular, the LL subband coefficients of the
whole face are fused with the histograms of uniform local binary
patterns from block partitions of the face. We applied the principal
component analysis on the fused features and managed to reduce the
dimensionality of the feature space from 536 down to around 15
without sacrificing too much accuracy. We have conducted a number
of preliminary experiments using a collection of 746 subject face
images. The test results show good accuracy and demonstrate the
potential of fusing global and local features. The fusion approach is
robust, making it easy to further improve the identification at both
feature and score levels.
Abstract: A SnO2/CdS/CdTe heterojunction was fabricated by
thermal evaporation technique. The fabricated cells were annealed at
573K for periods of 60, 120 and 180 minutes. The structural
properties of the solar cells have been studied by using X-ray
diffraction. Capacitance- voltage measurements were studied for the
as-prepared and annealed cells at a frequency of 102 Hz. The
capacitance- voltage measurements indicated that these cells are
abrupt. The capacitance decreases with increasing annealing time.
The zero bias depletion region width and the carrier concentration
increased with increasing annealing time. The carrier transport
mechanism for the CdS/CdTe heterojunction in dark is tunneling
recombination. The ideality factor is 1.56 and the reverse bias
saturation current is 9.6×10-10A. The energy band lineup for the n-
CdS/p-CdTe heterojunction was investigated using current - voltage
and capacitance - voltage characteristics.
Abstract: In this paper, the significant wave height at the Upper Gulf of Thailand and the changing of wave height at Bangkhuntien shoreline were simulated by using the Simulating WAves Nearshore Model (SWAN) version 40.51. The simulated results indicated that the significant wave height by SWAN model corresponded with the observed data. The results showed that the maximum significant wave height at the Bangkhuntien shoreline were 1.06-2.05 m. and the average significant wave height at the Bangkhuntien shoreline were 0.30-0.47 m. The significant wave height can be used to calculate the erosion through the Bangkhuntien shoreline. The erosion rates at the Bangkhuntien shoreline were prepared by using the aerial photo and they were about 1.80 m/yr. from 1980- 1986, 4.75 m/yr from 1987-1993, 15.28 m/yr from 1994-1996 and 10.03 m/yr from 1997-2002. The relation between the wave energy and the erosion were in good agreement. Therefore, the significant wave height was one of the major factors of the erosion at the Bangkhuntien shoreline.
Abstract: In the present work, an attempt has been made to
understand the feasibility of using UHF technique for identification
of any corona discharges/ arcing in insulating material due to water
droplets. The sensors of broadband type are useful for identification
of such discharges. It is realised that arcing initiated by liquid droplet
radiates UHF signals in the entire bandwidth up to 2 GHz. The
frequency content of the UHF signal generated due to corona/arcing
is not much varied in epoxy nanocomposites with different weight
percentage of clay content. The exfoliated/intercalated properties
were analysed through TEM studies. It is realized that corona
initiated discharges are of intermittent process. The hydrophobicity
of the material characterized through contact angle measurement. It
is realized that low Wt % of nanoclay content in epoxy resin reduces
the surface carbonization due to arcing/corona discharges. The results
of the study with gamma irradiated specimen indicates that contact
angle, discharge inception time and evaporation time of the liquid are
much lower than the virgin epoxy nanocomposite material.
Abstract: Quaternary InxAlyGa1-x-yN semiconductors have
attracted much research interest because the use of this quaternary
offer the great flexibility in tailoring their band gap profile while
maintaining their lattice-matching and structural integrity. The
structural and optical properties of InxAlyGa1-x-yN alloys grown by
molecular beam epitaxy (MBE) is presented. The structural quality of
InxAlyGa1-x-yN layers was characterized using high-resolution X-ray
diffraction (HRXRD). The results confirm that the InxAlyGa1-x-yN
films had wurtzite structure and without phase separation. As the In
composition increases, the Bragg angle of the (0002) InxAlyGa1-x-yN
peak gradually decreases, indicating the increase in the lattice constant
c of the alloys. FWHM of (0002) InxAlyGa1-x-yN decreases with
increasing In composition from 0 to 0.04, that could indicate the
decrease of quality of the samples due to point defects leading to
non-uniformity of the epilayers. UV-VIS spectroscopy have been used
to study the energy band gap of InxAlyGa1-x-yN. As the indium (In)
compositions increases, the energy band gap decreases. However, for
InxAlyGa1-x-yN with In composition of 0.1, the band gap shows a
sudden increase in energy. This is probably due to local alloy
compositional fluctuations in the epilayer. The bowing parameter
which appears also to be very sensitive on In content is investigated
and obtained b = 50.08 for quaternary InxAlyGa1-x-yN alloys. From
photoluminescence (PL) measurement, green luminescence (GL)
appears at PL spectrum of InxAlyGa1-x-yN, emitted for all x at ~530 nm
and it become more pronounced as the In composition (x) increased,
which is believed cause by gallium vacancies and related to isolated
native defects.
Abstract: Bursa, since the establishment of the Ottoman Empire,
being on the important trade roads and having a capital accumulation
as a result of silk production, was one of the first cities of
modernization activities applied. Bursa maintained its importance
even during the Republican Period and became one of the most
important cities of the country and today is the fourth biggest and the
industrialized city in Turkey. Social, political, economical and
cultural changes occured with the reforms starting with the 1839
Edict of Tanzimat that aimed at modernizing the society and the
government and centralizing the political power began in the
Ottoman Empire. After the Tanzimat Reforms transformation of the
city changed and planning processes began in Bursa according to the
vision of Governors. The theresholds of the city are very important
data for a sustainable planning for the city planners. Main aim of this
study is to investigate the changes and transformations of the city
according to the changes in the socio-economical and cultural
properties for the city planners.
Abstract: The IEEE802.16 standard which has emerged as
Broadband Wireless Access (BWA) technology, promises to deliver
high data rate over large areas to a large number of subscribers in the
near future. This paper analyze the effect of overheads over capacity
of downlink (DL) of orthogonal frequency division multiple access
(OFDMA)–based on the IEEE802.16e mobile WiMAX system with
and without overheads. The analysis focuses in particular on the
impact of Adaptive Modulation and Coding (AMC) as well as
deriving an algorithm to determine the maximum numbers of
subscribers that each specific WiMAX sector may support. An
analytical study of the WiMAX propagation channel by using Cost-
231 Hata Model is presented. Numerical results and discussion
estimated by using Matlab to simulate the algorithm for different
multi-users parameters.
Abstract: A model-free robust control (MFRC) approach is proposed for position control of robot manipulators in the state space. The control approach is verified analytically to be robust subject to uncertainties including external disturbances, unmodeled dynamics, and parametric uncertainties. There is a high flexibility to work on different systems including actuators by the use of the proposed control approach. The proposed control approach can guarantee the robustness of control system. A PUMA 560 robot driven by geared permanent magnet dc motors is simulated. The simulation results show a satisfactory performance for control system under technical specifications. KeywordsModel-free, robust control, position control, PUMA 560.
Abstract: Large full frequency band gaps of surface and bulk
acoustic waves in two-dimensional phononic band structures with
hollow cylinders are addressed in this paper. It is well-known that
absolute frequency band gaps are difficultly obtained in a band
structure consisted of low-acoustic-impedance cylinders in
high-acoustic-impedance host materials such as PMMA/Ni band
structures. Phononic band structures with hollow cylinders are
analyzed and discussed to obtain large full frequency band gaps not
only for bulk modes but also for surface modes. The tendency of
absolute frequency band gaps of surface and bulk acoustic waves is
also addressed by changing the inner radius of hollow cylinders in this
paper. The technique and this kind of band structure are useful for
tuning the frequency band gaps and the design of acoustic waveguides.