Abstract: An adaptive Helmholtz resonator was designed and
adapted to hydraulics. The resonator was controlled by open- and
closed-loop controls so that 20 dB attenuation of the peak-to-peak
value of the pulsating pressure was maintained. The closed-loop
control was noted to be better, albeit it was slower because of its low
pressure and temperature variation, which caused variation in the
effective bulk modulus of the hydraulic system. Low-pressure
hydraulics contains air, which affects the stiffness of the hydraulics,
and temperature variation changes the viscosity of the oil. Thus, an
open-loop control loses its efficiency if a condition such as
temperature or the amount of air changes after calibration. The
instability of the low-pressure hydraulic system reduced the
operational frequency range of the Helmholtz resonator when
compared with the results of an analytical model.
Different dampers for hydraulics are presented. Then analytical
models of a hydraulic pipe and a hydraulic pipe with a Helmholtz
resonator are presented. The analytical models are based on the wave
equation of sound pressure. Finally, control methods and the results
of experiments are presented.
Abstract: In this paper the application of neuro-fuzzy system for equalization of channel distortion is considered. The structure and operation algorithm of neuro-fuzzy equalizer are described. The use of neuro-fuzzy equalizer in digital signal transmission allows to decrease training time of parameters and decrease the complexity of the network. The simulation of neuro-fuzzy equalizer is performed. The obtained result satisfies the efficiency of application of neurofuzzy technology in channel equalization.
Abstract: In this paper, a new reverse converter for the moduli set {2n, 2n–1, 2n–1–1} is presented. We improved a previously introduced conversion algorithm for deriving an efficient hardware design for reverse converter. Hardware architecture of the proposed converter is based on carry-save adders and regular binary adders, without the requirement for modular adders. The presented design is faster than the latest introduced reverse converter for moduli set {2n, 2n–1, 2n–1–1}. Also, it has better performance than the reverse converters for the recently introduced moduli set {2n+1–1, 2n, 2n–1}
Abstract: In this paper, we apply the FM methodology to the
cross-section of Romanian-listed common stocks and investigate the
explanatory power of market beta on the cross-section of commons
stock returns from Bucharest Stock Exchange. Various assumptions
are empirically tested, such us linearity, market efficiency, the “no
systematic effect of non-beta risk" hypothesis or the positive
expected risk-return trade-off hypothesis. We find that the Romanian
stock market shows the same properties as the other emerging
markets in terms of efficiency and significance of the linear riskreturn
models. Our analysis included weekly returns from January
2002 until May 2010 and the portfolio formation, estimation and
testing was performed in a rolling manner using 51 observations (one
year) for each stage of the analysis.
Abstract: An efficient parallel form in digital signal processor can improve the algorithm performance. The butterfly structure is an important role in fast Fourier transform (FFT), because its symmetry form is suitable for hardware implementation. Although it can perform a symmetric structure, the performance will be reduced under the data-dependent flow characteristic. Even though recent research which call as novel memory reference reduction methods (NMRRM) for FFT focus on reduce memory reference in twiddle factor, the data-dependent property still exists. In this paper, we propose a parallel-computing approach for FFT implementation on digital signal processor (DSP) which is based on data-independent property and still hold the property of low-memory reference. The proposed method combines final two steps in NMRRM FFT to perform a novel data-independent structure, besides it is very suitable for multi-operation-unit digital signal processor and dual-core system. We have applied the proposed method of radix-2 FFT algorithm in low memory reference on TI TMSC320C64x DSP. Experimental results show the method can reduce 33.8% clock cycles comparing with the NMRRM FFT implementation and keep the low-memory reference property.
Abstract: To simulate heating systems in buildings, a research oriented computer code has been developed in Sharif University of Technology in Iran where the climate, existing heating equipment in buildings, consumer behavior and their interactions are considered for simulating energy consumption in conventional systems such as heaters, radiators and fan-coils. In order to validate the computer code, the available data of five buildings was used and the computed consumed energy was compared with the estimated energy extracted from monthly bills. The initial heating system was replaced by the alternative system and the effect of this change was observed on the energy consumption. As a result, the effect of changing heating equipment on energy consumption was investigated in different climates. Changing heater to radiator renders energy conservation up to 50% in all climates and changing radiator to fan-coil decreases energy consumption in climates with cold and dry winter.
Abstract: The Beijing road traffic system, as a typical huge
urban traffic system, provides a platform for analyzing the complex
characteristics and the evolving mechanisms of urban traffic systems.
Based on dynamic network theory, we construct the dynamic model
of the Beijing road traffic system in which the dynamical properties
are described completely. Furthermore, we come into the conclusion
that urban traffic systems can be viewed as static networks, stochastic
networks and complex networks at different system phases by
analyzing the structural randomness. As well as, we demonstrate the
evolving process of the Beijing road traffic network based on real
traffic data, validate the stochastic characteristics and the scale-free
property of the network at different phases
Abstract: User interaction components of Augmented Reality (AR) systems have to be tested with users in order to find and fix usability problems as early as possible. In this paper we will report on a user-centered design approach for AR systems following the experience acquired during the design and evaluation of a software prototype for an AR-based educational platform. In this respect we will focus on the re-design of the user task based on the results from a formative usability evaluation. The basic idea of our approach is to describe task scenarios in a tabular format, to develop a task model in a task modeling environment and then to simulate the execution.
Abstract: Pressure driven microscale gas flow-separation has
been investigated by solving the compressible Navier-Stokes (NS)
system of equations. A two dimensional explicit finite volume (FV)
compressible flow solver has been developed using modified
advection upwind splitting methods (AUSM+) with no-slip/first
order Maxwell-s velocity slip conditions to predict the flowseparation
behavior in microdimensions. The effects of scale-factor
of the flow geometry and gas species on the microscale gas flowseparation
have been studied in this work. The intensity of flowseparation
gets reduced with the decrease in scale of the flow
geometry. In reduced dimension, flow-separation may not at all be
present under similar flow conditions compared to the larger flow
geometry. The flow-separation patterns greatly depend on the
properties of the medium under similar flow conditions.
Abstract: There are many researches to detect collision between real object and virtual object in 3D space. In general, these techniques are need to huge computing power. So, many research and study are constructed by using cloud computing, network computing, and distribute computing. As a reason of these, this paper proposed a novel fast 3D collision detection algorithm between real and virtual object using 2D intersection area. Proposed algorithm uses 4 multiple cameras and coarse-and-fine method to improve accuracy and speed performance of collision detection. In the coarse step, this system examines the intersection area between real and virtual object silhouettes from all camera views. The result of this step is the index of virtual sensors which has a possibility of collision in 3D space. To decide collision accurately, at the fine step, this system examines the collision detection in 3D space by using the visual hull algorithm. Performance of the algorithm is verified by comparing with existing algorithm. We believe proposed algorithm help many other research, study and application fields such as HCI, augmented reality, intelligent space, and so on.
Abstract: This paper presents a set of guidelines for the design
of multi-user awareness systems. In a first step, general requirements
for team awareness systems are analyzed. In the second part of the
paper, the identified requirements are aggregated and transformed
into concrete design guidelines for the development of team
awareness systems.
Abstract: A control system design with Characteristic Ratio
Assignment (CRA) is proven that effective for SISO control design.
But the control system design for MIMO via CRA is not concrete
procedure. In this paper presents the control system design method
for quadruple-tank process via CRA. By using the decentralized
method for both minimum phase and non-minimum phase are made.
The results from PI and PID controller design via CRA can be
illustrated the validity of our approach by MATLAB.
Abstract: Recently, the improvements in processing performance
of a computer and in high speed communication of an optical fiber
have been achieved, so that the amount of data which are processed
by a computer and flowed on a network has been increasing greatly.
However, in a client-server system, since the server receives and
processes the amount of data from the clients through the network, a
load on the server is increasing. Thus, there are needed to introduce
a server with high processing ability and to have a line with high
bandwidth. In this paper, concerning to P2P networks to resolve the
load on a specific server, a criterion called an Indexed-Priority Metric
is proposed and its performance is evaluated. The proposed metric is
to allocate some files to each node. As a result, the load on a specific
server can distribute them to each node equally well. A P2P file
sharing system using the proposed metric is implemented. Simulation
results show that the proposed metric can make it distribute files on
the specific server.
Abstract: Efficient utilization of existing water is a pressing
need for Pakistan. Due to rising population, reduction in present
storage capacity and poor delivery efficiency of 30 to 40% from
canal. A study to evaluate an irrigation system in the cotton-wheat
zone of Pakistan, after the watercourse lining was conducted. The
study is made on the basis of cropping pattern and salinity to evaluate
the system. This study employed an index-based approach of using
Geographic information system with field data. The satellite images
of different years were use to examine the effective area. Several
combinations of the ratio of signals received in different spectral
bands were used for development of this index. Near Infrared and
Thermal IR spectral bands proved to be most effective as this
combination helped easy detection of salt affected area and cropping
pattern of the study area. Result showed that 9.97% area under
salinity in 1992, 9.17% in 2000 and it left 2.29% in year 2005.
Similarly in 1992, 45% area is under vegetation it improves to 56%
and 65% in 2000 and 2005 respectively. On the basis of these results
evaluation is done 30% performance is increase after the watercourse
improvement.
Abstract: Along with forward supply chain organization needs
to consider the impact of reverse logistics due to its economic
advantage, social awareness and strict legislations. In this paper, we
develop a system dynamics framework for a closed-loop supply
chain with fuzzy demand and fuzzy collection rate by incorporating
product exchange policy in forward channel and various recovery
options in reverse channel. The uncertainty issues associated with
acquisition and collection of used product have been quantified using
possibility measures. In the simulation study, we analyze order
variation at both retailer and distributor level and compare bullwhip
effects of different logistics participants over time between the
traditional forward supply chain and the closed-loop supply chain.
Our results suggest that the integration of reverse logistics can reduce
order variation and bullwhip effect of a closed-loop system. Finally,
sensitivity analysis is performed to examine the impact of various
parameters on recovery process and bullwhip effect.
Abstract: The peng-Robinson (PR), a cubic equation of state (EoS), is extended to polymers by using a single set of energy (A1, A2, A3) and co-volume (b) parameters per polymer fitted to experimental volume data. Excellent results for the volumetric behavior of the 11 polymer up to 2000 bar pressure are obtained. The EoS is applied to the correlation and prediction of Henry constants in polymer solutions comprising three polymer and many nonpolar and polar solvents, including supercritical gases. The correlation achieved with two adjustable parameter is satisfactory compared with the experimental data. As a result, the present work provides a simple and useful model for the prediction of Henry's constant for polymer containing systems including those containing polar, nonpolar and supercritical fluids.
Abstract: The problem of updating damped gyroscopic systems using measured modal data can be mathematically formulated as following two problems. Problem I: Given Ma ∈ Rn×n, Λ = diag{λ1, ··· , λp} ∈ Cp×p, X = [x1, ··· , xp] ∈ Cn×p, where p
Abstract: Context awareness is a capability whereby mobile
computing devices can sense their physical environment and adapt
their behavior accordingly. The term context-awareness, in
ubiquitous computing, was introduced by Schilit in 1994 and has
become one of the most exciting concepts in early 21st-century
computing, fueled by recent developments in pervasive computing
(i.e. mobile and ubiquitous computing). These include computing
devices worn by users, embedded devices, smart appliances, sensors
surrounding users and a variety of wireless networking technologies.
Context-aware applications use context information to adapt
interfaces, tailor the set of application-relevant data, increase the
precision of information retrieval, discover services, make the user
interaction implicit, or build smart environments. For example: A
context aware mobile phone will know that the user is currently in a
meeting room, and reject any unimportant calls. One of the major
challenges in providing users with context-aware services lies in
continuously monitoring their contexts based on numerous sensors
connected to the context aware system through wireless
communication. A number of context aware frameworks based on
sensors have been proposed, but many of them have neglected the
fact that monitoring with sensors imposes heavy workloads on
ubiquitous devices with limited computing power and battery. In this
paper, we present CALEEF, a lightweight and energy efficient
context aware framework for resource limited ubiquitous devices.
Abstract: Knowledge discovery from text and ontology learning
are relatively new fields. However their usage is extended in many
fields like Information Retrieval (IR) and its related domains. Human
Plausible Reasoning based (HPR) IR systems for example need a
knowledge base as their underlying system which is currently made
by hand. In this paper we propose an architecture based on ontology
learning methods to automatically generate the needed HPR
knowledge base.
Abstract: Finger spelling is an art of communicating by signs
made with fingers, and has been introduced into sign language to serve
as a bridge between the sign language and the verbal language.
Previous approaches to finger spelling recognition are classified into
two categories: glove-based and vision-based approaches. The
glove-based approach is simpler and more accurate recognizing work
of hand posture than vision-based, yet the interfaces require the user to
wear a cumbersome and carry a load of cables that connected the
device to a computer. In contrast, the vision-based approaches provide
an attractive alternative to the cumbersome interface, and promise
more natural and unobtrusive human-computer interaction. The
vision-based approaches generally consist of two steps: hand
extraction and recognition, and two steps are processed independently.
This paper proposes real-time vision-based Korean finger spelling
recognition system by integrating hand extraction into recognition.
First, we tentatively detect a hand region using CAMShift algorithm.
Then fill factor and aspect ratio estimated by width and height
estimated by CAMShift are used to choose candidate from database,
which can reduce the number of matching in recognition step. To
recognize the finger spelling, we use DTW(dynamic time warping)
based on modified chain codes, to be robust to scale and orientation
variations. In this procedure, since accurate hand regions, without
holes and noises, should be extracted to improve the precision, we use
graph cuts algorithm that globally minimize the energy function
elegantly expressed by Markov random fields (MRFs). In the
experiments, the computational times are less than 130ms, and the
times are not related to the number of templates of finger spellings in
database, as candidate templates are selected in extraction step.