Water cycle algorithm for solving the reliability-redundancy allocation problem with a choice of redundancy strategies

Abstract

This paper proposes a new mathematical model for the reliability-redundancy allocation problem (RRAP) with a choice of redundancy strategies. To maximize the reliability of a system, this model chooses the best redundancy strategy from among both active and standby ones for each subsystem. For those with a standby strategy, a continuous time Markov chain model is used to calculate the exact reliability values. In order to solve the proposed mixed-integer non-linear programing model, a powerful evolutionary algorithm, called water cycle algorithm (WCA), is developed and implemented on three famous benchmark problems. Finally, the results of different benchmark problems are compared with those previously reported to show the superiority of the proposed model and the efficiency of WCA.     

Effect of Sociocultural Context and Parenting Style on Scholastic Achievement among Iranian Adolescents

School grades, family demographics and responses to the parental authority questionnaire were assessed in 240 eighth‐grade students in the southern, central and northern parts of Tehran, Iran's capital. The result showed that poorer families with traditional values had more authoritarian attitudes toward parenting than richer families with more modern values. In contrast to the studies conducted in East Asian societies, the current study found that authoritative parenting was the style associated with the highest academic outcome. Tests of mediation and moderation effects showed that the relation between parenting style and academic outcome was independent of sociocultural context.     

Gambling motivations and superstitious beliefs: a cross-cultural study with casino customers

The expansion of legalized commercial gaming in Macau has motivated stakeholders to explore opportunities in other Asian countries. However, there is a lack of research focusing on casino customers in these markets. Thus, the purpose of this study is to explore gambling superstitious beliefs and motivations of those visiting a casino in South Korea, and how these factors are different across four ethnic groups. The researchers surveyed 323 casino customers in the lounge area on the casino floor, including Americans, Chinese, Japanese, and Koreans living abroad. This study found American gamblers could be characterized as more superstitious than Japanese gamblers, while the Chinese and American gamblers exhibited many similarities regarding the pattern of superstitious beliefs that they were most likely to endorse. The findings also suggest the culture and the area around the casino might be more important to Chinese, while novelty to Japanese and winning money to Korean gamblers are seen as most important. This study contributes to gambling literature by examining gamblers’ beliefs and motives in a different setting with more diverse populations than those in previous studies. The findings of this study will help casino operators properly develop and adjust strategies to thrive in the Asian marketplace.     

The Evolution of Housing Typologies for Older Adults in The Netherlands From 1945 to 2016: An Analysis in the Context of Policy,Societal, and Technological Developments

This study aims to examine housing typologies for older adults in the light of three qualitatively examined exogenous factors: policy, societal developments, and technology. The developments in inpatient and assisted ambulatory housing facilities for older adults have been mapped from 1945 to 2016 using quantitative data. Using these data, five transition periods can be distinguished. Within the first transition periods, policy factors were tremendously important, while within the later ones, societal influence empowered by technological change became the primarily driving factor. This research shows that the classification of inpatient, assisted ambulatory housing, and outpatient housing may no longer be applicable in its current form.     

Topics on Dynamic Panel Data Models with Random Effects Using Semi-Parametric Bayesian Approach

A common assumption in fitting panel data models is normality of stochastic subject effects. This can be extremely restrictive, making vague most potential features of true distributions. The objective of this article is to propose a modeling strategy, from a semi-parametric Bayesian perspective, to specify a flexible distribution for the random effects in dynamic panel data models. This is addressed here by assuming the Dirichlet process mixture model to introduce Dirichlet process prior for the random-effects distribution. We address the role of initial conditions in dynamic processes, emphasizing on joint modeling of start-up and subsequent responses. We adopt Gibbs sampling techniques to approximate posterior estimates. These important topics are illustrated by a simulation study and also by testing hypothetical models in two empirical contexts drawn from economic studies. We use modified versions of information criteria to compare the fitted models.     

To Tell or Not to Tell? The Ethical Dilemma of the Would-Be Whistleblower

Despite the growing emphasis placed on the responsible conduct of research, little attention has been devoted to the question of what an individual should do upon discovering research misconduct. This article takes seriously the dilemma of a would-be whistleblower. It identifies ethical considerations that can be taken into account in moral decision-making about reporting research misconduct. It also offers rough guidelines about the moral significance of each consideration in the decision-making process based on the facts of the case in question. The article, therefore, offers tools for a would-be whistleblower to use to arrive at a defensible resolution to a difficult dilemma.     

The Public Sector and income distribution in South Africa during the period 1970–82

This study considers the impact of fiscal and monetary policy on the distribution of income in South Africa. It analyses expenditure using two approaches: (1) the general approach which considers the extent of programmes having a relatively high distributive contact in favour of the poor and (2) the direct money‐flow approach which assumes that expenditure benefits those who receive it as their income. Although neither approach is perfect, it can be concluded that the general composition of expenditure has favoured the poor. It is also argued that the tax system is partly progressive and partly regressive and that it has become more regressive, although remaining in balance progressive. Monetary policy during the 1970s, however, has had definite regressive income distribution effects.     

A sustainable supply chain network considering lot sizing with quantity discounts under disruption risks: centralized and decentralized models

This study proposes a framework for the main parties of a sustainable supply chain network considering lot-sizing impact with quantity discounts under disruption risk among the first studies. The proposed problem differs from most studies considering supplier selection and order allocation in this area. First, regarding the concept of the triple bottom line, total cost, environmental emissions, and job opportunities are considered to cover the criteria of sustainability. Second, the application of this supply chain network is transformer production. Third, applying an economic order quantity model lets our model have a smart inventory plan to control the uncertainties. Most significantly, we present both centralized and decentralized optimization models to cope with the considered problem. The proposed centralized model focuses on pricing and inventory decisions of a supply chain network with a focus on supplier selection and order allocation parts. This model is formulated by a scenario-based stochastic mixed-integer non-linear programming approach. Our second model focuses on the competition of suppliers based on the price of products with regard to sustainability. In this regard, a Stackelberg game model is developed. Based on this comparison, we can see that the sum of the costs for both levels is lower than the cost without the bi-level approach. However, the computational time for the bi-level approach is more than for the centralized model. This means that the proposed optimization model can better solve our problem to achieve a better solution than the centralized optimization model. However, obtaining this better answer also requires more processing time. To address both optimization models, a hybrid bio-inspired metaheuristic as the hybrid of imperialist competitive algorithm (ICA) and particle swarm optimization (PSO) is utilized. The proposed algorithm is compared with its individuals. All employed optimizers have been tuned by the Taguchi method and validated by an exact solver in small sizes. Numerical results show that striking similarities are observed between the results of the algorithms, but the standard deviations of PSO and ICA–PSO show better behavior. Furthermore, while PSO consumes less time among the metaheuristics, the proposed hybrid metaheuristic named ICA–PSO shows more time computations in all small instances. Finally, the provided results confirm the efficiency and the performance of the proposed framework and the proposed hybrid metaheuristic algorithm.