Abstract: Safety instrumented systems (SISs) are becoming
increasingly complex and the proportion of programmable electronic
parts is growing. The IEC 61508 global standard was established to
ensure the functional safety of SISs, but it was expressed in highly
macroscopic terms. This study introduces an evaluation process for
hardware safety integrity levels through failure modes, effects, and
diagnostic analysis (FMEDA).FMEDA is widely used to evaluate
safety levels, and it provides the information on failure rates and
failure mode distributions necessary to calculate a diagnostic coverage
factor for a given component. In our evaluation process, the
components of the SIS subsystem are first defined in terms of failure
modes and effects. Then, the failure rate and failure mechanism
distribution are assigned to each component. The safety mode and
detectability of each failure mode are determined for each component.
Finally, the hardware safety integrity level is evaluated based on the
calculated results.
Abstract: It is important to predict yield in semiconductor test process in order to increase yield. In this study, yield prediction means finding out defective die, wafer or lot effectively. Semiconductor test process consists of some test steps and each test includes various test items. In other world, test data has a big and complicated characteristic. It also is disproportionably distributed as the number of data belonging to FAIL class is extremely low. For yield prediction, general data mining techniques have a limitation without any data preprocessing due to eigen properties of test data. Therefore, this study proposes an under-sampling method using support vector machine (SVM) to eliminate an imbalanced characteristic. For evaluating a performance, randomly under-sampling method is compared with the proposed method using actual semiconductor test data. As a result, sampling method using SVM is effective in generating robust model for yield prediction.
Abstract: Employee-s task performance has been recognized as a
core contributor to overall organizational effectiveness. Hence,
verifying the determinants of task performance is one of the most
important research issues. This study tests the influence of perceived
organizational support, abusive supervision, and exchange ideology
on employee-s task performance. We examined our hypotheses by
collecting self-reported data from 413 Korean employees in different
organizations. Our all hypotheses gained support from the results.
Implications for research and directions for future research are
discussed.
Abstract: This analysis investigates the distortion of flow
measurement and the increase of cavitation along orifice
flowmeter. The analysis using the numerical method (CFD)
validated the distortion of flow measurement through the inlet
velocity profile considering the convergence and grid
dependency. Realizable k-e model was selected and y+ was
about 50 in this numerical analysis. This analysis also estimated
the vulnerability of cavitation effect due to inlet velocity profile.
The investigation concludes that inclined inlet velocity profile
could vary the pressure which was measured at pressure tab
near pipe wall and it led to distort the pressure values ranged
from -3.8% to 5.3% near the orifice plate and to make the
increase of cavitation. The investigation recommends that the
fully developed inlet velocity flow is beneficial to accurate flow
measurement in orifice flowmeter.
Abstract: In this paper, we proposed the distribution of mesh
normal vector direction as a feature descriptor of a 3D model. A
normal vector shows the entire shape of a model well. The
distribution of normal vectors was sampled in proportion to each
polygon's area so that the information on the surface with less surface
area may be less reflected on composing a feature descriptor in order
to enhance retrieval performance. At the analysis result of ANMRR,
the enhancement of approx. 12.4%~34.7% compared to the existing
method has also been indicated.
Abstract: Though nonlinear dynamic analysis using a specialized
hydro-code such as AUTODYN is accurate and useful tool for
progressive collapse assessment of a multi-story building subjected to
blast load, it takes too much time to be applied to a practical simulation
of progressive collapse of a tall building. In this paper, blast analysis of
a RC frame structure using a simplified model with Reinforcement
Contact technique provided in Ansys Workbench was introduced and
investigated on its accuracy. Even though the simplified model has a
fraction of elements of the detailed model, the simplified model with
this modeling technique shows similar structural behavior under the
blast load to the detailed model. The proposed modeling method can
be effectively applied to blast loading progressive collapse analysis of
a RC frame structure.
Abstract: An ontology is widely used in many kinds of applications as a knowledge representation tool for domain knowledge. However, even though an ontology schema is well prepared by domain experts, it is tedious and cost-intensive to add instances into the ontology. The most confident and trust-worthy way to add instances into the ontology is to gather instances from tables in the related Web pages. In automatic populating of instances, the primary task is to find the most proper concept among all possible concepts within the ontology for a given table. This paper proposes a novel method for this problem by defining the similarity between the table and the concept using the overlap of their properties. According to a series of experiments, the proposed method achieves 76.98% of accuracy. This implies that the proposed method is a plausible way for automatic ontology population from Web tables.
Abstract: At any point of time, a power system operating
condition should be stable, meeting various operational criteria and it
should also be secure in the event of any credible contingency. Present
day power systems are being operated closer to their stability limits
due to economic and environmental constraints. Maintaining a stable
and secure operation of a power system is therefore a very important
and challenging issue. Voltage instability has been given much
attention by power system researchers and planners in recent years,
and is being regarded as one of the major sources of power system
insecurity. Voltage instability phenomena are the ones in which the
receiving end voltage decreases well below its normal value and does
not come back even after setting restoring mechanisms such as VAR
compensators, or continues to oscillate for lack of damping against the
disturbances. Reactive power limit of power system is one of the major
causes of voltage instability. This paper investigates the effects of
coordinated series capacitors (SC) with static VAR compensators
(SVC) on steady-state voltage stability of a power system. Also, the
influence of the presence of series capacitor on static VAR
compensator controller parameters and ratings required to stabilize
load voltages at certain values are highlighted.
Abstract: The rapid advance of communication technology is
evolving the network environment into the broadband convergence
network. Likewise, the IT services operated in the individual network
are also being quickly converged in the broadband convergence
network environment. VoIP and IPTV are two examples of such new
services. Efforts are being made to develop the video phone service,
which is an advanced form of the voice-oriented VoIP service.
However, the new IT services will be subject to stability and reliability
vulnerabilities if the relevant security issues are not answered during
the convergence of the existing IT services currently being operated in
individual networks within the wider broadband network
environment. To resolve such problems, this paper attempts to analyze
the possible threats and identify the necessary security measures
before the deployment of the new IT services. Furthermore, it
measures the quality of the encryption algorithm application example
to describe the appropriate algorithm in order to present security
technology that will have no negative impact on the quality of the
video phone service.
Abstract: Recommender systems are usually regarded as an
important marketing tool in the e-commerce. They use important
information about users to facilitate accurate recommendation. The
information includes user context such as location, time and interest
for personalization of mobile users. We can easily collect information
about location and time because mobile devices communicate with the
base station of the service provider. However, information about user
interest can-t be easily collected because user interest can not be
captured automatically without user-s approval process. User interest
usually represented as a need. In this study, we classify needs into two
types according to prior research. This study investigates the
usefulness of data mining techniques for classifying user need type for
recommendation systems. We employ several data mining techniques
including artificial neural networks, decision trees, case-based
reasoning, and multivariate discriminant analysis. Experimental
results show that CHAID algorithm outperforms other models for
classifying user need type. This study performs McNemar test to
examine the statistical significance of the differences of classification
results. The results of McNemar test also show that CHAID performs
better than the other models with statistical significance.
Abstract: Since MEMS gyro sensors measure not angle of rotation but angular rate, an estimator is designed to estimate the angles in many applications. Gyro and accelerometer are used to improve estimating accuracy of the angle. This paper presents a method of finding filter coefficients of the well-known estimator which is to get rotation angles from gyro and accelerometer data. In order to verify the performance of our method, the estimated angle is compared with the encoder output in a rotary pendulum system.
Abstract: The objective of this work is to investigate the
turbulent reacting flow in a three dimensional combustor with
emphasis on the effect of inlet swirl flow through a numerical
simulation. Flow field is analyzed using the SIMPLE method which is
known as stable as well as accurate in the combustion modeling, and
the finite volume method is adopted in solving the radiative transfer
equation. In this work, the thermal and flow characteristics in a three
dimensional combustor by changing parameters such as equivalence
ratio and inlet swirl angle have investigated. As the equivalence ratio
increases, which means that more fuel is supplied due to a larger inlet
fuel velocity, the flame temperature increases and the location of
maximum temperature has moved towards downstream. In the mean
while, the existence of inlet swirl velocity makes the fuel and
combustion air more completely mixed and burnt in short distance.
Therefore, the locations of the maximum reaction rate and temperature
were shifted to forward direction compared with the case of no swirl.
Abstract: Primary barrier of membrane type LNG containment system consist of corrugated 304L stainless steel. This 304L stainless steel is austenitic stainless steel which shows different material behaviors owing to phase transformation during the plastic work. Even though corrugated primary barriers are subjected to significant amounts of pre-strain due to press working, quantitative mechanical behavior on the effect of pre-straining at cryogenic temperatures are not available. In this study, pre-strain level and pre-strain temperature dependent tensile tests are carried to investigate mechanical behaviors. Also, constitutive equations with material parameters are suggested for a verification study.
Abstract: Wheat gluten hydrolyzates (WGHs) and anchovy fine
powder hydrolyzates (AFPHs) were produced at 300 MPa using
combinations of Flavourzyme 500MG (F), Alcalase 2.4L (A),
Marugoto E (M) and Protamex (P), and then were compared to those
produced at ambient pressure concerning the contents of soluble solid
(SS), soluble nitrogen and electrophoretic profiles. The contents of SS
in the WGHs and AFPHs increased up to 87.2% according to the
increase in enzyme number both at high and ambient pressure. Based
on SS content, the optimum enzyme combinations for one-, two-,
three- and four-enzyme hydrolysis were determined as F, FA, FAM
and FAMP, respectively. Similar trends were found for the contents of
total soluble nitrogen (TSN) and TCA-soluble nitrogen (TCASN). The
contents of SS, TSN and TCASN in the hydrolyzates together with
electrophoretic mobility maps indicates that the high-pressure
treatment of this study accelerated protein hydrolysis compared to
ambient-pressure treatment.
Abstract: An advanced composite flywheel rotor consisting of
intra and inter hybrid rims was designed to optimally increase the energy capacity, and was manufactured using filament winding with
in-situ curing. The flywheel has recently attracted considerable attention from many investigators since it possesses great potential in
many energy storage applications, including electric utilities, hybrid or
electric automobiles, and space vehicles. In this investigation, a comprehensive study was conducted with the intent to implement
composites in high performance flywheel applications.The inner two
intra-hybrid rims (rims 1 and 2) were manufactured as a whole part
through continuous filament winding under in-situ curing conditions,
and so were the outer two rims (rims 3 and 4). The outer surface of rim
2 and the inner surface of rim 3 were CNC-tapered for press-fitting. Machined rims were finally press-fitted using a hydraulic press with a
maximum compressive force of approximately 1000 ton.
Abstract: Numerical simulations are performed for laminar
continuous and pulsed jets impinging on a surface in order to
investigate the effects of pulsing frequency on the heat transfer
characteristics. The time-averaged Nusselt number of pulsed jets is
larger in the impinging jet region as compared to the continuous jet,
while it is smaller in the outer wall jet region. At the stagnation point,
the mean and RMS Nusselt numbers become larger and smaller,
respectively, as the pulsing frequency increases. Unsteady behaviors
of vortical fluid motions and temperature field are also investigated to
understand the underlying mechanisms of heat transfer enhancement.
Abstract: Arms detection is one of the fundamental problems in
human motion analysis application. The arms are considered as the
most challenging body part to be detected since its pose and speed
varies in image sequences. Moreover, the arms are usually occluded
with other body parts such as the head and torso. In this paper,
histogram-based skin colour segmentation is proposed to detect the
arms in image sequences. Six different colour spaces namely RGB,
rgb, HSI, TSL, SCT and CIELAB are evaluated to determine the best
colour space for this segmentation procedure. The evaluation is
divided into three categories, which are single colour component,
colour without luminance and colour with luminance. The
performance is measured using True Positive (TP) and True Negative
(TN) on 250 images with manual ground truth. The best colour is
selected based on the highest TN value followed by the highest TP
value.
Abstract: This paper presents a mathematical model and a
methodology to analyze the losses in transmission expansion
planning (TEP) under uncertainty in demand. The methodology is
based on discrete particle swarm optimization (DPSO). DPSO is a
useful and powerful stochastic evolutionary algorithm to solve the
large-scale, discrete and nonlinear optimization problems like TEP.
The effectiveness of the proposed idea is tested on an actual
transmission network of the Azerbaijan regional electric company,
Iran. The simulation results show that considering the losses even for
transmission expansion planning of a network with low load growth
is caused that operational costs decreases considerably and the
network satisfies the requirement of delivering electric power more
reliable to load centers.
Abstract: Soil washing process with a surfactant solution is a potential technology for the rapid removal of hydrophobic organic compound (HOC) from soil. However, large amount of washed water would be produced during operation and this should be treated effectively by proper methods. The soil washed water for complex contaminated site with HOC and heavy metals might contain high amount of pollutants such as HOC and heavy metals as well as used surfactant. The heavy metals in the soil washed water have toxic effects on microbial activities thus these should be removed from the washed water before proceeding to a biological waste-water treatment system. Moreover, the used surfactant solutions are necessary to be recovered for reducing the soil washing operation cost. In order to simultaneously remove the heavy metals and HOC from soil-washed water, activated carbon (AC) was used in the present study. In an anionic-nonionic surfactant mixed solution, the Cd(II) and phenanthrene (PHE) were effectively removed by adsorption on activated carbon. The removal efficiency for Cd(II) was increased from 0.027 mmol-Cd/g-AC to 0.142 mmol-Cd/g-AC as the mole ratio of SDS increased in the presence of PHE. The adsorptive capacity of PHE was also increased according to the SDS mole ratio due to the decrement of molar solubilization ratios (MSR) for PHE in an anionic-nonionic surfactant mixture. The simultaneous adsorption of HOC and cationic heavy metals using activated carbon could be a useful method for surfactant recovery and the reduction of heavy metal toxicity in a surfactant-enhanced soil washing process.
Abstract: A satured liquid is warmed until boiling in a parallelepipedic boiler. The heat is supplied in a liquid through the horizontal bottom of the boiler, the other walls being adiabatic. During the process of boiling, the liquid evaporates through its free surface by deforming it. This surface which subdivides the boiler into two regions occupied on both sides by the boiled liquid (broth) and its vapor which surmounts it. The broth occupying the region and its vapor the superior region. A two- fluids model is used to describe the dynamics of the broth, its vapor and their interface. In this model, the broth is treated as a monophasic fluid (homogeneous model) and form with its vapor adiphasic pseudo fluid (two-fluid model). Furthermore, the interface is treated as a zone of mixture characterized by superficial void fraction noted α* . The aim of this article is to describe the dynamics of the interface between the boiled fluid and its vapor within a boiler. The resolution of the problem allowed us to show the evolution of the broth and the level of the liquid.