A New Hybrid Model for Improvement of ARIMA by DEA

The classic ARIMA models use the information criteria for lag selection since 1990s. The information criteria are based on the summation of two expressions: a function of Residual Sum of Squares (RSS) and a penalty for decrease of degrees of freedom. However, the information criteria have some disadvantages since these two expressions do not have the same scale, so the information criteria are mainly based on the first expression (because of its bigger scale). In this paper, we propose a hybrid ARIMA model, which uses the Data Envelopment Analysis (DEA) model to select the best lags of AR and MA process called DEA-ARIMA. DEA is a linear programming technique, which computes a comparative ratio of multiple outputs to multiple inputs for each Decision Making Unit (DMU), which is reported as the relative efficiency score. We identify inputs as the number of AR and MA terms and outputs of the model are inverse of Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE). In fact, in our proposed model, inputs consider as resources, so we are looking for some models with fewer resources and high efficiency. The DEA unlike the information criteria may have more than one solution and all of them are efficient so to compare this two models selection the mean of best DMUs is calculated. Experimental results demonstrate DEA-ARIMA will not trap in over fitting problem in contrast to classic ARIMA models because of considering a set of efficient ARIMA models

RANKING THE SPECTATORS’ DIFFICULTIES IN PURCHASING ELECTRONIC TICKETS OF FOOTBALL PREMIER LEAGUE

This study aimed to rank the spectators’ difficulties in buying electronic tickets of football premier league matches at Azadi stadium. The population consisted of all spectators of Esteghlal-Persepolis match in the fifteenth league at Azadi stadium (N= 100000). According to Morgan table and using simple random sampling method, 500 participants were selected as sample. A researcher-made questionnaire was used for collecting the data; its face validity was confirmed by 15 experts and performing a pilot study on 30 subjects, its Cronbach’s alpha was calculated to be 0.86. Using SPSS 22, the descriptive and inferential (including Friedman test) statistics was applied for analyzing the data. The findings showed that there was a significant difference between rankings of difficulties in buying electronic tickets of Football premier league matches at Azadi Stadium. The difficulties were ranked as: problem in ticket systems, early selling out of electronic tickets, lack of confidence to electronic ticket sale, lack of skill to work with the internet, low speed of internet, and lack of access to the interne

A Hybrid Approach for Thread Recommendation in MOOC Forums

Recommender Systems have been developed to provide contents and services compatible to users based on their behaviors and interests. Due to information overload in online discussion forums and users diverse interests, recommending relative topics and threads is considered to be helpful for improving the ease of forum usage. In order to lead learners to find relevant information in educational forums, recommendations are even more needed. We present a hybrid thread recommender system for MOOC forums by applying social network analysis and association rule mining techniques. Initial results indicate that the proposed recommender system performs comparatively well with regard to limited available data from users' previous posts in the forum

Gasoline Additives

Gasoline – the most common petroleum product comes in several types or grades. Straight-run gasoline is generated solely by crude oil distillation. Crack gasoline, derived by thermal or catalytic breaking of heavier oil fractions, accounts for the majority of gasoline used in automobile and aviation. Straight-run gasoline, fractured gasoline, reformed and synthetic gasoline, and additives are used to create a wide range of gasoline kinds.Бензин – наиболее распространенный нефтепродукт, выпускаемый в нескольких видах или сортах. Прямогонный бензин производится исключительно путем перегонки сырой нефти. Крекинг-бензин, получаемый путем термического или каталитического расщепления более тяжелых нефтяных фракций, составляет большую часть бензина, используемого в автомобилестроении и авиации. Прямогонный бензин, фракционированный бензин, реформированный и синтетический бензин, а также присадки используются для создания широкого спектра видов бензина.Используемые программы Adobe Acroba

High sensitivity surface plasmon resonance (SPR) refractive index sensor in 1.5 μm

A surface plasmon resonance (SPR) based sensor is proposed and demonstrated for operation in the 1500 nm region. The sensor operates by the immersion of microfibers with a 25-μm diameter waist in chemical solutions that have varying external effective refractive indices. The sensor is fabricated using a homemade single-mode tapered fiber with a uniform waist coated on all sides with a gold layer approximately 45 nm thick by means of a vacuum electron beam evaporator machine. The transmission dips in the sensor’s optical spectrum are highly responsive to any perturbations in the external medium refractive index, thus providing high sensitivity. The proposed sensor system has multiple potential applications in biological and chemical constituent and reaction measurements

Self-reported risk behaviors among offender motorcyclists in Ahvaz City

Introduction: Road traffic accidents are among the most critical public health issues. Many people die on the roads each day and tens of millions sustain nonfatal injuries. The aim of this study is to describe the high-risk behaviors of motorcyclists in which police had to confiscate their motorcycles. Methods: This cross-sectional study was carried out on 240 motorcyclists in Iran from December 2010 to February 2011. A researcher-created questionnaire was used to collect data on self-reported high-risk behaviors, including passing the crossroads without considering the traffic light, refusing to wear a helmet, performing stunts in the street, and driving in the opposite direction. The collected data was descriptively analyzed. Results: The mean age of motorcyclists was 29.3 years (SD=8.26). Twenty-six percent (n=62) of the participants did not have a motorcycle driver’s license. The analysis of risk behaviors showed that 60.8% (n=146) of the motorcycle drivers usually passed crossroads without considering the traffic light and 20.8% (n=50) performed stunts in the street. Conclusions: This study indicates that the prevalence of high-risk behaviors among motorcyclists is significant. Health education interventions may inhibit these behaviors, thus reducing the risk of injuries