Abstract: Electrical resistivity is a fundamental parameter of metals or electrical conductors. Since resistivity is a function of temperature, in order to completely understand the behavior of metals, a temperature dependent theoretical model is needed. A model based on physics principles has recently been developed to obtain an equation that relates electrical resistivity to temperature. This equation is dependent upon a parameter associated with the electron travel time before being scattered, and a parameter that relates the energy of the atoms and their separation distance. Analysis of the energy parameter reveals that the equation is optimized if the proportionality term in the equation is not constant but varies over the temperature range. Additional analysis reveals that the theoretical equation can be used to determine the mean free path of conduction electrons, the number of defects in the atomic lattice, and the ‘equivalent’ charge associated with the metallic bonding of the atoms. All of this analysis provides validation for the theoretical model and provides insight into the behavior of metals where performance is affected by temperatures (e.g., integrated circuits and temperature sensors).
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: This paper presents the design and implementation of a fully integrated transimpedance amplifier (TIA) as the analog frontend receiver for Capacitive Micromachined Ultrasound Transducers (CMUTs) for ultrasound biomicroscope imaging application. The amplifier is designed to amplify the received signals from 17.5MHz to 52.5MHz with a center frequency of 35MHz. The TIA was fabricated in GF 0.18μm 1P6M 30V high voltage process. The measurement results show that the designed amplifier can reach a transimpedance gain of 61.08dBΩ and operating frequency from 17.5MHz to 100MHz with 1VP-P output voltage under 6V power supply.
Abstract: Sorghum flour was supplemented with 15 and 30%
chickpea flour. Sorghum flour and the supplement were fermented at
35 oC for 0, 8, 16, and 24 h. Changes in pH, titrable acidity, total
soluble solids, protein content, in vitro protein digestibility and
amino acid composition were investigated during fermentation and/or
after supplementation of sorghum flour with chickpea. The pH of the
fermenting material decreased sharply with a concomitant increase in
the titrable acidity. The total soluble solids remained unchanged with
progressive fermentation time. The protein content of sorghum
cultivar was found to be 9.27 and that of chickpea was 22.47%. The
protein content of sorghum cultivar after supplementation with15 and
30% chickpea was significantly (P ≤ 0.05) increased to 11.78 and
14.55%, respectively. The protein digestibility also increased after
fermentation from 13.35 to 30.59 and 40.56% for the supplements,
respectively. Further increment in protein content and digestibility
was observed when supplemented and unsupplemented samples were
fermented for different periods of time. Cooking of fermented
samples was found to increase the protein content slightly and
decreased digestibility for both supplements. Amino acid content of
fermented and fermented and cooked supplements was determined.
Supplementation was found to increase the lysine and therionine
content. Cooking following fermentation decreased lysine,
isoleucine, valine and sulfur containg amino acids.
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: Group work, projects and discussions are important
components of teacher education courses whether they are face-toface,
blended or exclusively online formats. This paper examines the varieties of tasks and challenges with this learning format in a face to
face class teacher education class providing specific examples of both
failure and success from both the student and instructor perspective.
The discussion begins with a brief history of collaborative and cooperative learning, moves to an exploration of the promised
benefits and then takes a look at some of the challenges which can
arise specifically from the use of new technologies. The discussion concludes with guidelines and specific suggestions.
Abstract: The experiment was performed to evaluate the effect
of GA3, 2,4-D on fruit growth and fruit quality of wax apple. The
experiment consisted of Red A, Monulla, Atu, Red B cultivars. GA3
and 2,4-D were applied at the small bud and petal fall stage.
Physiological, biochemical characters of fruit were recoded. The
result showed application of GA3, 2,4-D greatly response in
increasing fruit set for all treatment as compared to control. Fruit
weight, fruit size were increased at 10 ppm 2,4-D in ‘Red A’, ‘Red
B’, however it was also enhancing at 10 ppm GA3 in ‘Monulla’,
‘Atu’. For ‘Monulla’, ‘Atu’ fruit crack reduced by 10 ppm 2,4-D
application, but ‘Red B’, ‘Red A’ gave least fruit crack at 10 and 30
ppm GA3, respectively. ‘Monulla’, ‘Atu’ and ‘Red B’ resulted in
response well to 10 ppm GA3 on improving TSS, whereas
application of 30 ppm GA3 greatly enhancing TSS in ‘Red A’. For
‘Atu’ titratable acidity markedly reduced by 10 ppm GA3
application, but spraying with 30 ppm GA3 greatly response in
reducing titratable acidity in ‘Red A’, ‘Red B’ and ‘Monulla’. It was
concluded that GA3, 2,4-D can be an effective tool to enhancing fruit
set, fruit growth as well as improving fruit quality of wax apple.
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: Prolonged immobilization leads to significant
weakness and atrophy of the skeletal muscle and can also impair the
recovery of muscle strength following injury. Therefore, it is
important to minimize the period under immobilization and accelerate
the return to normal activity. This study examined the effects of heat
treatment and rest-inserted exercise on the muscle activity of the lower
limb during knee flexion/extension. Twelve healthy subjects were
assigned to 4 groups that included: (1) heat treatment + rest-inserted
exercise; (2) heat + continuous exercise; (3) no heat + rest-inserted
exercise; and (4) no heat + continuous exercise. Heat treatment was
applied for 15 mins prior to exercise. Continuous exercise groups
performed knee flexion/extension at 0.5 Hz for 300 cycles without rest
whereas rest-inserted exercise groups performed the same exercise but
with 2 mins rest inserted every 60 cycles of continuous exercise.
Changes in the rectus femoris and hamstring muscle activities were
assessed at 0, 1, and 2 weeks of treatment by measuring the
electromyography signals of isokinetic maximum voluntary
contraction. Significant increases in both the rectus femoris and
hamstring muscles were observed after 2 weeks of treatment only
when both heat treatment and rest-inserted exercise were performed.
These results suggest that combination of various treatment techniques,
such as heat treatment and rest-inserted exercise, may expedite the
recovery of muscle strength following immobilization.
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 study extends research on the relationship
between marketing strategy and market segmentation by
investigating on market segments in the cement industry.
Competitive strength and rivals distance from the factory were used
as business environment. A three segment (positive, neutral or
indifferent and zero zones) were identified as strategic segments. For
each segment a marketing strategy (aggressive, defensive and
decline) were developed. This study employed data from cement
industry to fulfill two objectives, the first is to give a framework to
the segmentation of cement industry and the second is developing
marketing strategy with varying competitive strength. Fifty six
questionnaires containing close-and open-ended questions were
collected and analyzed. Results supported the theory that segments
tend to be more aggressive than defensive when competitive strength
increases. It is concluded that high strength segments follow total
market coverage, concentric diversification and frontal attack to their
competitors. With decreased competitive strength, Business tends to
follow multi-market strategy, product modification/improvement and
flank attack to direct competitors for this kind of segments. Segments
with weak competitive strength followed focus strategy and decline
strategy.
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 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: When programming in languages such as C, Java, etc.,
it is difficult to reconstruct the programmer's ideas only from the
program code. This occurs mainly because, much of the programmer's
ideas behind the implementation are not recorded in the code during
implementation. For example, physical aspects of computation such as
spatial structures, activities, and meaning of variables are not required
as instructions to the computer and are often excluded. This makes the
future reconstruction of the original ideas difficult. AIDA, which is a
multimedia programming language based on the cyberFilm model, can
solve these problems allowing to describe ideas behind programs
using advanced annotation methods as a natural extension to
programming. In this paper, a development environment that
implements the AIDA language is presented with a focus on the
annotation methods. In particular, an actual scientific numerical
computation code is created and the effects of the annotation methods
are analyzed.
Abstract: With the increasing complexity of engineering
problems, the traditional, single-objective and deterministic
optimization method can not meet people-s requirements. A
multi-objective fuzzy optimization model of resource input is built for
M chlor-alkali chemical eco-industrial park in this paper. First, the
model is changed into the form that can be solved by genetic algorithm
using fuzzy theory. And then, a fitness function is constructed for
genetic algorithm. Finally, a numerical example is presented to show
that the method compared with traditional single-objective
optimization method is more practical and efficient.
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: The current study describes a multi-objective optimization technique for positioning of houses in a residential neighborhood. The main task is the placement of residential houses in a favorable configuration satisfying a number of objectives. Solving the house layout problem is a challenging task. It requires an iterative approach to satisfy design requirements (e.g. energy efficiency, skyview, daylight, roads network, visual privacy, and clear access to favorite views). These design requirements vary from one project to another based on location and client preferences. In the Gulf region, the most important socio-cultural factor is the visual privacy in indoor space. Hence, most of the residential houses in this region are surrounded by high fences to provide privacy, which has a direct impact on other requirements (e.g. daylight and direction to favorite views). This investigation introduces a novel technique to optimally locate and orient residential buildings to satisfy a set of design requirements. The developed technique explores the search space for possible solutions. This study considers two dimensional house planning problems. However, it can be extended to solve three dimensional cases.