Applications of fuzzy theories to multi-objective system optimization

Most of the computer aided design techniques developed so far deal with the optimization of a single objective function over the feasible design space. However, there often exist several engineering design problems which require a simultaneous consideration of several objective functions. This work presents several techniques of multiobjective optimization. In addition, a new formulation, based on fuzzy theories, is also introduced for the solution of multiobjective system optimization problems. The fuzzy formulation is useful in dealing with systems which are described imprecisely using fuzzy terms such as, 'sufficiently large', 'very strong', or 'satisfactory'. The proposed theory translates the imprecise linguistic statements and multiple objectives into equivalent crisp mathematical statements using fuzzy logic. The effectiveness of all the methodologies and theories presented is illustrated by formulating and solving two different engineering design problems. The first one involves the flight trajectory optimization and the main rotor design of helicopters. The second one is concerned with the integrated kinematic-dynamic synthesis of planar mechanisms. The use and effectiveness of nonlinear membership functions in fuzzy formulation is also demonstrated. The numerical results indicate that the fuzzy formulation could yield results which are qualitatively different from those provided by the crisp formulation. It is felt that the fuzzy formulation will handle real life design problems on a more rational basis

Improvement of Learning and Memory of Mice by Plumbagin

Roots of Plumbago zeylanica have been reported to improve learning and memory of mice, but the effect of plumbagin on learning and memory of mice and the possible mechanisms for its effect on memory have not been explored till date. So the present study was designed to evaluate the effect of plumbagin on learning and memory of Swiss young male albino mice. Plumbagin (4, 8, 16 mg/kg, p.o.) and physostigmine (0.1 mg/kg,i.p.) per se were administered for 15 successive days to separate groups of mice. Behavioral parameters of learning and memory were recorded using Morris water maze. Acetylcholinesterase activity was estimated in brain of mice. Effect of plumbagin on scopolamine (0.4 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.)-induced amnesia was also investigated. Locomotor activities of mice were also recorded. Plumbagin (8 and 16 mg/kg) and physostigmine significantly improved learning and memory of mice, as indicated by decrease in escape latency during training and increase in time spent in target quadrant of Morris water maze during retrieval. The drugs did not show any significant effect on locomotor activities of mice. Memory improving activity of plumbagin (16 mg/kg) was equivalent to physostigmine. Plumbagin significantly reversed scopolamine- and diazepam- induced amnesia in mice. Plumbagin and physostigmine also significantly reduced brain acetylcholinesterase activity of mice. In conclusion, plumbagin significantly improved memory of mice possibly through inhibition of brain acetylcholinesterase activity and through involvement of GABA-benzodiazepine pathway. Thus, plumbagin may be explored further for management of cognitive dysfunction

Monopolistic competition and optimum product diversity under firm heterogeneity

Empirical work has drawn attention to the high degree of productivity differences within industries, and its role in resource allocation. This paper examines the allocational efficiency of such markets. Productivity differences introduce two new margins of potential inefficiency: selection of the right distribution of firms and allocation of the right quantities across firms. We show that these considerations impact welfare and policy analysis and market power across firms leads to distortions in resource allocation. Demand-side elasticities determine how resources are misallocated and when increased competition from market expansion provides welfare gains

Discomfort, Pressure Distribution and Safety in Operator's Seat-A Critical Review

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is an Invited Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 5 (2003): H. Dhingra, V. Tewari, and S. Singh. Discomfort, Pressure Distribution and Safety in Operator's Seat-A Critical Review. Vol. V. July 2003

“I Don’t Mind Being Ugly but I Don’t Wanna Have Skin Cancer”: A Qualitative Study of Attitudes to UV Exposure and a Facial Morphing Intervention in Men 35 Years and Older

Objectives: Skin cancer is a growing problem globally. Older men have been largely ignored in previous research, even though men may generally be prone to riskier exposure to the sun than women. Past research suggests that appearance-focused techniques such as facial morphing can increase motivations to use sun protection among women of all ages, and younger men. Design: was qualitative, consisting of individual interviews. Method: was semi-structured interviews with 25 older men, to examine attitudes to UV exposure and reactions to a facial morphing intervention. Interviews were subjected to thematic analysis. Results: Three themes were constructed: masculine UV exposure; appearance that’s accepted; personal responsibility. The men did not identify gaps in their sun protection behaviour, and demonstrated a lack of concern about ageing and appearance. These attitudes translated into a lack of motivation for behaviour change due to ageing acceptance. However, motivation to change behaviour came from health concerns resulting from the intervention. Conclusions: The men experienced different motivations and barriers for sun protection use than women of similar ages. Facial morphing can be effective with older men, but may need to be reframed to focus on health implications and personal choice

Gender differences and correlates of extreme dieting behaviours in US adolescents.

This article examined correlates of and gender differences in extreme dieting behaviours among 15,425 US adolescents from the 2011 Youth Risk Behavior Survey. Suicidal thoughts and plans and binge drinking were related to extreme dieting behaviours in females, but not in males. Suicide attempts, daily smoking and marijuana use were related to extreme dieting behaviours in males, but not females. Results suggest extreme dieting behaviours are associated with a range of negative psychosocial factors and substance use behaviours, and that these differ for boys and girls. Additional research is required to elucidate these relationships, and these results provide a focus for future research, prevention and intervention efforts

Criminal social identity and suicide ideation among Pakistani young prisoners.

© Emerald Group Publishing Limited. Purpose: Suicidal behaviour is a common in prisoners, yet little is known about the factors that may protect against thoughts of ending one's life. The purpose of this paper is to specify and test a structural model to examine the relationship between three criminal social identity (CSI) dimensions (in-group affect, in-group ties, and cognitive centrality) and suicide ideation while controlling for period of confinement, age, criminal friends, and offense type (violent vs non-violent). Design/methodology/approach: Participants were 415 male juvenile offenders incarcerated in prisons in Khyber Pakhtunkhwa Pakistan. A structural model was specified and tested using Mplus to examine the relationships between the three factors of CSI and suicidal thoughts, while controlling for age, offender type, period of confinement, and substance dependence. Findings: The model provided an adequate fit for the data, explaining 22 per cent of variance in suicidal thoughts. In-group affect (the level of personal bonding with other criminals) was found to exert a strong protective effect against suicide ideation. Originality/value: The research contributes important information on suicide ideation in Pakistan, an Islamic country in which suicide is considered a sin and subsequently a criminal offence. Results indicate that Juvenile offenders' sense of shared identity may help to prevent the development of thoughts of death by suicide. Consequently, separating and isolating young prisoners may be ill advised

Latent classes of delinquent behaviour associated with criminal social identity among juvenile offenders in Pakistan

© Emerald Group Publishing Limited. Purpose – The purpose of this paper is to examine the number and nature of latent classes of delinquency that exist among male juvenile offenders incarcerated in prisons in Pakistan. Design/methodology/approach – The sample consisted of 415 young male offenders incarcerated in prisons in Khyber Pakhtunkhwa (KPK) Pakistan. Latent class analysis was employed to determine the number and nature of delinquency latent classes. Multinomial logistic regression was used to estimate the associations between latent classes and the three factors of criminal social identity (cognitive centrality, in-group affect, and in-group ties) whilst controlling for criminal friends, period of confinement, addiction, age, and location. Findings – The best fitting latent class model was a three-class solution. The classes were labelled: “minor delinquents” (the baseline/normative class; Class 3), “major delinquents” (Class 1), and “moderate delinquents” (Class 2). Class membership was predicted by differing external variables. Specifically, Class 1 membership was related to having more criminal friends; while Class 2 membership was related to lower levels of in-group affect and higher levels of in-group ties. Practical implications – Findings are discussed in relation to refining current taxonomic arguments regarding the structure of delinquency and implications for prevention of juvenile delinquent behaviour. Originality/value – First, most previous studies have focused on school children, whereas, this paper focuses on incarcerated juvenile offenders. Second, this research includes delinquents from Pakistan, whereas, most previous research has examined delinquent behaviour in western cultures