Abstract: A forecasting model for steel demand uncertainty in Thailand is proposed. It consists of trend, autocorrelation, and outliers in a hierarchical Bayesian frame work. The proposed model uses a cumulative Weibull distribution function, latent first-order autocorrelation, and binary selection, to account for trend, time-varying autocorrelation, and outliers, respectively. The Gibbs sampling Markov Chain Monte Carlo (MCMC) is used for parameter estimation. The proposed model is applied to steel demand index data in Thailand. The root mean square error (RMSE), mean absolute percentage error (MAPE), and mean absolute error (MAE) criteria are used for model comparison. The study reveals that the proposed model is more appropriate than the exponential smoothing method.
Abstract: Technical analysis comprised by various technical indicators is a holistic way of representing price movement of stocks in the market. Various forms of indicators have evolved from the primitive ones in the past decades. There have been many attempts to introduce volume as a major determinant to determine strong patterns in market forecasting. The law of demand defines the relationship between the volume and price. Most of the traders are familiar with the volume game. Including the time dimension to the law of demand provides a different visualization to the theory. While attempting the same, it was found that there are different thresholds in the market for different companies. These thresholds have a significant influence on the price. This article is an attempt in determining the thresholds for companies using the three dimensional graphs for optimizing the portfolios. It also emphasizes on the magnitude of importance of volumes as a key factor for determining of predicting strong price movements, bullish and bearish markets. It uses a comprehensive data set of major companies which form a major chunk of the Indian automotive sector and are thus used as an illustration.
Abstract: In an increasingly connected world, where speed of communication attempts to match the speed of thought and thus intentions; conflict gets actioned faster using media like the internet and telecommunication technology. This has led to a new form of aggression: “cyber bullying”. The present paper attempts to integrate existing theory on bullying, and the dark triad personality traits in a work environment and extrapolate it to the cyber context.
Abstract: This paper presents a nonparametric method to obtain the hazard rate “Bathtub curve” for power system components. The model is a mixture of the three known phases of a component life, the decreasing failure rate (DFR), the constant failure rate (CFR) and the increasing failure rate (IFR) represented by three parametric Weibull models. The parameters are obtained from a simultaneous fitting process of the model to the Kernel nonparametric hazard rate curve. From the Weibull parameters and failure rate curves the useful lifetime and the characteristic lifetime were defined. To demonstrate the model the historic time-to-failure of distribution transformers were used as an example. The resulted “Bathtub curve” shows the failure rate for the equipment lifetime which can be applied in economic and replacement decision models.
Abstract: This paper introduces a new generalization of the two parameter Weibull distribution. To this end, the quadratic rank transmutation map has been used. This new distribution is named exponentiated transmuted Weibull (ETW) distribution. The ETW distribution has the advantage of being capable of modeling various shapes of aging and failure criteria. Furthermore, eleven lifetime distributions such as the Weibull, exponentiated Weibull, Rayleigh and exponential distributions, among others follow as special cases. The properties of the new model are discussed and the maximum likelihood estimation is used to estimate the parameters. Explicit expressions are derived for the quantiles. The moments of the distribution are derived, and the order statistics are examined.
Abstract: This paper presents a detailed description of evaporative cooling systems used for space cooling in Mina Valley, Saudi Arabia. The thermal performance and environmental impact of the evaporative coolers were evaluated. It was found that the evaporative cooling systems used for space cooling in pilgrims’ accommodations and in the train stations could reduce energy consumption by as much as 75% and cut carbon dioxide emission by 78% compared to traditional vapour compression systems.
Abstract: Television news has gained a new dimension in terms
of ideological approaches as a result of such factors as globalization,
cross monopolization, presence of international companies etc. and
certain strategies have been developed at the production, presentation
and distribution stages of news. In this study, television news about a
process called “settlement process” was investigated. In this
framework, news about the settlement process on TV channels of
TRT 1, ATV, FOX TV, NTV, HABERTÜRK, TRT HABER and
STV was investigated using the content analysis method in terms of
the strategies the ideology construction, attitude towards the party in
power, attitude towards parties in opposition and attitude towards
BDP (Peace and Democracy Part) and Imrali (the island where
Abdullah Ocalan, head of PKK, is kept). First, the aforementioned
TV channels were selected randomly from 3 groups in order to be
able to reveal the representational capacity of commercial, news and
public channels.
The study covers 557 news items broadcast in the main news
bulletins between the dates of 15 March 2013 and 15 March 2013.
While there was a positive attitude towards the government in a
sizable portion of the news about the settlement process (63.6%), the
attitude of 25.3% of the news was impartial towards the government
and 11.3% had a negative attitude. On the other hand, there was a
negative attitude towards the Opposition in a considerable portion of
the news about the settlement process (56.1%). The attitude of 35.9%
of the news towards the Opposition was impartial whereas 8.0% had
a positive attitude. While 34.9% of the news about the settlement
process used the legitimization strategy from among the ideology
construction strategies, 22.8% used the unification strategy, 15.7%
the reification strategy, 15.6% fractional and 11%
concealment/mystification strategy.
Abstract: This investigation presents preparation of sample and
analysis of results of ballistic impact test as per EN 1063 on the size,
thickness, number, position, and type of the bonding interlayer
Polyvinyl Butyral, Poly Carbonate and Poly Urethane on bullet proof
glass. It was observed that impact energy absorbed by bullet proof
glass increases with the increase of the total thickness from 33mm to
42mm to 51mm for all the three samples respectively. Absorption
impact energy is greater for samples with more number of bonding
interlayers than with the number of glass layers for uniform increase
in total sample thickness. There is no effect on the absorption impact
energy with the change in position of the bonding interlayer.
Abstract: This paper discusses the effects of using progressive Type-I right censoring on the design of the Simple Step Accelerated Life testing using Bayesian approach for Weibull life products under the assumption of cumulative exposure model. The optimization criterion used in this paper is to minimize the expected pre-posterior variance of the Pth percentile time of failures. The model variables are the stress changing time and the stress value for the first step. A comparison between the conventional and the progressive Type-I right censoring is provided. The results have shown that the progressive Type-I right censoring reduces the cost of testing on the expense of the test precision when the sample size is small. Moreover, the results have shown that using strong priors or large sample size reduces the sensitivity of the test precision to the censoring proportion. Hence, the progressive Type-I right censoring is recommended in these cases as progressive Type-I right censoring reduces the cost of the test and doesn't affect the precision of the test a lot. Moreover, the results have shown that using direct or indirect priors affects the precision of the test.
Abstract: The fracture performance of steel wires for civil engineering applications remains a major concern in civil engineering construction and maintenance of wire reinforced structures. The need to employ approaches that simulate micromechanical material processes which characterizes fracture in civil structures has been emphasized recently in the literature. However, choosing from the numerous micromechanics-based fracture models, and identifying their applicability and reliability remains an issue that still needs to be addressed in a greater depth. Laboratory tensile testing and finite element tensile testing simulations with the shear, ductile and Gurson-Tvergaard-Needleman’s micromechanics-based models conducted in this work reveal that the shear fracture model is an appropriate fracture model to predict the fracture performance of steel wires used for civil engineering applications. The need to consider the capability of the micromechanics-based fracture model to predict the “cup and cone” fracture exhibited by the wire in choosing the appropriate fracture model is demonstrated.
Abstract: With the use of developing technology, mostly in communication and entertainment, students spend considerable time on the Internet. In addition to the advantages provided by the Internet, social isolation brings problems such as addiction. This is one of the problems of the virtual violence. Cyber bullying is the common name of the intensities which students are exposed on the Internet. The purpose of this study designed as a qualitative research is to find out the cyber bullying varieties and its effects on elementary school students. The participants of this research are 6th, 7th and 8th grade students of a primary school and 24 students agreed to participate in the study. The students were asked to fill an interview with semi-structured open-ended questions. According to the results obtained in the research, the most important statements determined by the participants are breaking passwords on social networking sites, slang insult to blasphemy and taking friendship offers from unfamiliar people. According to participants from the research, the most used techniques to prevent themselves from cyber bullying are to complain to the site administrator, closing accounts on social networking sites and countercharging. Also, suggestions were presented according to the findings.
Abstract: In this study, tapioca starch, which acts as natural polymer, was added in the blend in order to produce biodegradable product. Low density polyethylene (LDPE) and tapioca starch blends were prepared by extrusion and the test sample by injection moulding process. Ethylene vinyl acetate (EVA) acts as compatibilizer while glycerol as processing aid was added in the blend. The blends were characterized by using melt flow index (MFI), fourier transform infrared (FTIR) and the effects of water absorption to the sample. As the starch content increased, MFI of the blend was decreased. Tensile testing were conducted shows the tensile strength and elongation at break decreased while the modulus increased as the starch increased. For the biodegradation, soil burial test was conducted and the loss in weight was studied as the starch content increased. Morphology studies were conducted in order to show the distribution between LDPE and starch.
Abstract: This paper presents the experimental investigation of on-body channel fading at 2.45 GHz considering two effects of the user body movement; stationary and mobile. A pair of body-worn antennas was utilized in this measurement campaign. A statistical analysis was performed by comparing the measured on-body path loss to five well-known distributions; lognormal, normal, Nakagami, Weibull and Rayleigh. The results showed that the average path loss of moving arm varied higher than the path loss in sitting position for upper-arm-to-left-chest link, up to 3.5 dB. The analysis also concluded that the Nakagami distribution provided the best fit for most of on-body static link path loss in standing still and sitting position, while the arm movement can be best described by log-normal distribution.
Abstract: Sometimes the amount of time available for testing could be considerably less than the expected lifetime of the component. To overcome such a problem, there is the accelerated life-testing alternative aimed at forcing components to fail by testing them at much higher-than-intended application conditions. These models are known as acceleration models. One possible way to translate test results obtained under accelerated conditions to normal using conditions could be through the application of the “Maxwell Distribution Law.” In this paper we will apply a combined approach of a sequential life testing and an accelerated life testing to a low alloy high-strength steel component used in the construction of overpasses in Brazil. The underlying sampling distribution will be three-parameter Inverse Weibull model. To estimate the three parameters of the Inverse Weibull model we will use a maximum likelihood approach for censored failure data. We will be assuming a linear acceleration condition. To evaluate the accuracy (significance) of the parameter values obtained under normal conditions for the underlying Inverse Weibull model we will apply to the expected normal failure times a sequential life testing using a truncation mechanism. An example will illustrate the application of this procedure.
Abstract: This paper discusses the application of extreme events distribution taking the Limpopo River Basin at Xai-Xai station, in Mozambique, as a case analysis. We analyze the extreme value concepts, namely Gumbel, Fréchet, Weibull and Generalized Extreme Value Distributions and then extrapolate the original data to 1000, 5000 and 10000 figures for further simulations and we compare their outcomes based on these three main distributions.
Abstract: The presented paper copes with an experimental evaluation of a model based on modified Weibull size effect theory. Classical statistical Weibull theory was modified by introducing a new parameter (correlation length lp) representing the spatial autocorrelation of a random mechanical properties of material. This size effect modification was observed on two different materials used in civil engineering: unreinforced (plain) concrete and multi-filament yarns made of alkaliresistant (AR) glass which are used for textile-reinforced concrete. The behavior under flexural, resp. tensile loading was investigated by laboratory experiments. A high number of specimens of different sizes was tested to obtain statistically significant data which were subsequently corrected and statistically processed. Due to a distortion of the measured displacements caused by the unstiff experiment device, only the maximal load values were statistically evaluated. Results of the experiments showed a decreasing strength with an increasing sample length. Size effect curves were obtained and the correlation length was fitted according to measured data. Results did not exclude the existence of the proposed new parameter lp.
Abstract: The impacts of near-campus student housing, or offcampus
students accommodation cannot be ignored by the
universities and as well as the community officials. Numerous
scholarly studies, have highlighted the substantial economic impacts
either; direct, indirect or induced, and cumulatively the roles of the
universities have significantly contributed to the local economies.
The issue of the impacts of off-campus student rental housing on
neighbourhoods is one that has been of long-standing but increasing
concern in Malaysia. Statistically, in Malaysia, there was
approximately a total of 1.2 - 1.5 million students in 2009. By the
year 2015, it is expected that 50 per cent of 18 to 30 year olds active
population should gain access to university education, amounting to
120,000 yearly. The objectives of the research are to assess the
impacts off-campus students on the local neighbourhood and
specifically to obtain information on the living and learning
conditions of off-campus students of Universiti Teknologi MARA
Shah Alam, Malaysia. It is also to isolate those factors that may
impede the successful learning so that priority can be given to them
in subsequent policy implementations and actions by government and
the higher education institutions.
Abstract: Vehicular Ad-hoc Network (VANET) is taking more
attention in automotive industry due to the safety concern of human
lives on roads. Security is one of the safety aspects in VANET. To be
secure, network availability must be obtained at all times since
availability of the network is critically needed when a node sends any
life critical information to other nodes. However, it can be expected
that security attacks are likely to increase in the coming future due to
more and more wireless applications being developed and deployed
onto the well-known expose nature of the wireless medium. In this
respect, the network availability is exposed to many types of attacks.
In this paper, Denial of Service (DOS) attack on network availability
is presented and its severity level in VANET environment is
elaborated. A model to secure the VANET from the DOS attacks has
been developed and some possible solutions to overcome the attacks
have been discussed.
Abstract: In this paper we will develop a sequential life test approach applied to a modified low alloy-high strength steel part used in highway overpasses in Brazil.We will consider two possible underlying sampling distributions: the Normal and theInverse Weibull models. The minimum life will be considered equal to zero. We will use the two underlying models to analyze a fatigue life test situation, comparing the results obtained from both.Since a major chemical component of this low alloy-high strength steel part has been changed, there is little information available about the possible values that the parameters of the corresponding Normal and Inverse Weibull underlying sampling distributions could have. To estimate the shape and the scale parameters of these two sampling models we will use a maximum likelihood approach for censored failure data. We will also develop a truncation mechanism for the Inverse Weibull and Normal models. We will provide rules to truncate a sequential life testing situation making one of the two possible decisions at the moment of truncation; that is, accept or reject the null hypothesis H0. An example will develop the proposed truncated sequential life testing approach for the Inverse Weibull and Normal models.
Abstract: Constant upgrading of Enterprise Resource Planning
(ERP) systems is necessary, but can cause new defects. This paper
attempts to model the likelihood of defects after completed upgrades
with Weibull defect probability density function (PDF). A case study
is presented analyzing data of recorded defects obtained for one ERP
subsystem. The trends are observed for the value of the parameters
relevant to the proposed statistical Weibull distribution for a given
one year period. As a result, the ability to predict the appearance of
defects after the next upgrade is described.