Urban Growth and Housing Quality in Iran

Rapid urban population growth and the lack of effective policies in order to desired population settlement, has encountered Iran’s major cities with multiple social, economic and environment problems. Physical expansion of cities in order to settlement the increasing population, causes the formation of new textures surrounding old urban textures. In the new textures, urban housing is formed with the modern approach and least logical connection with common practice in the old textures. Therefore, the main objective of this paper is to evaluate the housing quality and identify strengths and weaknesses in old and new urban textures to improve the quality of urban housing in Iran. Household survey were conducted to collect the needed data in the old and new textures in Khorramabad city. Results showed that the satisfaction level of housing quality in new texture is far more than old ones. The highest satisfaction level in both textures are related to housing basic facilities domain. However, satisfaction level of this domain in new texture is much greater compared to the old texture. The lowest level of satisfaction is related to the quality of neighborhood domain in old texture and to the access to public services domain in the new one. Results from the factor analysis to identify the dimensions of housing quality in old and new textures illustrated that housing quality is a multidimensional concept, studying of which requires considering all dimensions and aspects.     

Bayesian Analysis of Skew Gaussian Spatial Models Based on Censored Data

The customary approach to spatial data modeling in the presence of censored data, is to assume the underlying random field is Gaussian. However, in practice, we often faced data that the exploratory data analysis shows the skewness and consequently, it violates the normality assumption. In such setting, the skew Gaussian (SG) spatial model is used to overcome this issue. In this article, the SG model is fitted based on censored observations. For this purpose, we adopt the Bayesian approach and utilize the Markov chain Monte Carlo algorithms and data augmentations to carry out calculations. A numerical example illustrates the methodology.     

Designing an ergonomics backpack for student aged 7-9 with user centred design approach

Researches explored that backpacks are the most common means of carrying school supplies for students. Carrying heavy backpacks causes a wide range of disorders such as musculoskeletal disorders and postural malfunction. User Centered Design has proven its suitability to produce high efficient products with the most adaptability to consumer demands. This approach combined with consideration of normal standards and ergonomics features, with the recognition of children's needs and requirements, has been used in this research to prepare an initial design of a backpack. After that, its prototype was manufactured. The backpack was tested by 120 elementary students in three steps of form, ergonomics and load sense. A redesign was performed that has applied the results of the test run. Results showed that this new backpack can considerably reduce the effective loads on the shoulders, back and neck.     

Economic design of VSI X̄ control chart with correlated non-normal data under multiple assignable causes

It has been recently revealed that the Shewhart control charts with variable sampling interval (VSI) perform better than the traditional Shewhart chart with the fixed sampling interval in detecting shifts in the process. In most of these research works, the normality and independency of the process data or measurements are assumed and that the process is subjected to only one assignable cause. While, in practice, these assumptions usually do not hold, some recent studies are focused on working with only one or two of these violations. In this paper, the situation in which the process data are correlated and follow a non-normal distribution and that there is multiplicity of assignable causes in the process is considered. For this case, a cost model for the economic design of the VSI X? control chart is developed, where the Burr distribution is employed to represent the non-normal distribution of the process data. To obtain the optimal values of the design parameters, a genetic algorithm is employed in which the response surface methodology is applied. A numerical example is presented to show the applicability and effectiveness of the proposed methodology. Sensitivity analysis is also carried out to evaluate the effects of cost and input parameters on the performance of the chart.     

Robust surface estimation in multi-response multistage statistical optimization problems

As the ordinary least squares (OLS) method is very sensitive to outliers as well as to correlated responses, a robust coefficient estimation method is proposed in this paper for multi-response surfaces in multistage processes based on M-estimators. In this approach, experimental designs are used in which the intermediate response variables may act as covariates in the next stages. The performances of both the ordinary multivariate OLS and the proposed robust multi-response surface approach are analyzed and compared through extensive simulation experiments. Sum of the squared errors in estimating the regression coefficients reveals the efficiency of the proposed robust approach.     

Examining the Notion of Listening Subskill Divisibility and its Implications for Second Language Listening

The testing and teaching of listening has been partially guided by the notion of subskills, or a set of listening abilities that are needed for achieving successful comprehension and utilization of the information from listening texts. Although this notion came about mainly through applications of theoretical perspectives from psychology and communication studies, the actual divisibility of the subskills has rarely been examined. This article reports an attempt to do so by using data from the answers of 916 test takers of a retired version of the Michigan English Language Assessment Battery listening test. First, an iterative content analysis of items was carried out, identifying five key subskills. Next, the discriminability of subskills was examined through confirmatory factor analysis (CFA). Five independent measurement models representing the subskills were evaluated. The overall CFA model comprising the measurement models showed excessively high correlations among factors. Further tests through CFA resolved the inadmissible correlations, though the high correlations persisted. Finally, we made 23 aggregate-level items which were used in a higher-order model, which induced best fit indices and resolved the inadmissible estimates. The results show that the subskills in the test were empirically divisible, lending support to scholarly attempts in discussing components in the listening construct for the purpose of teaching and assessment.     

Modified branching process for the reliability analysis of complex systems: Multiple-robot systems

Current design practice is usually to produce a safety system which meets a target level of performance that is deemed acceptable by the regulators. Safety systems are designed to prevent or alleviate the consequences of potentially hazardous events. In many modern industries the failure of such systems can lead to whole system breakdown. In reliability analysis of complex systems involving multiple components, it is assumed that the components have different failure rates with certain probabilities. This leads into extensive computational efforts involved in using the commonly employed generating function (GF) and the recursive algorithm to obtain reliability of systems consisting of a large number of components. Moreover, when the system failure results in fatalities it is desirable for the system to achieve an optimal rather than adequate level of performance given the limitations placed on available resources. This paper concerns with developing a modified branching process joint with generating function to handle reliability evaluation of a multi-robot complex system. The availability of the system is modeled to compute the failure probability of the whole system as a performance measure. The results help decision-makers in maintenance departments to analyze critical components of the system in different time periods to prevent system breakdowns.     

Modeling the effectiveness of urban agriculture education courses

Urban Ecosystems - Urban agriculture can provide food security that is essential to sustainable development goals. Citizen education plays a vital role in urban agriculture formation. The present...