Procurement process: Decision by exclusion and pairwise comparisons

Two case studies illustrate multicriteria decision making techniques frequently used in procurement practice: least-cost sufficient performance and weighted utility optimization. Both techniques have defects and are rarely robust. Decision by exclusion and pairwise comparisons is proposed as a third approach which eliminates inferior alternatives by generalized forms of minimum performance requirements established under multicriteria framework. It is more robust and maintains high level of accountability.     

Estimation of an Asymmetric Stochastic Volatility Model for Asset Returns

A stochastic volatility model may be estimated by a quasi-maximum likelihood procedure by transforming to a linear state-space form. The method is extended to handle correlation between the two disturbances in the model and applied to data on stock returns     

Sex, age, season, and habitual physical activity of older Japanese: the Nakanojo study

The interactions of sex, age, season, and habitual physical activity were examined in 41 male and 54 female Japanese age 65-83 yr, using a pedometer/accelerometer that determined step counts and amounts of physical activity (<3 and >3 metabolic equivalents [METs]) throughout each 24-hr period for an entire year. All 3 measures were greater in men than in women. In women, age was negatively correlated with step count and activity <3 METs, but in men, it was correlated with step count and activity >3 METs. Irrespective of sex or age, all 3 activity variables were low in the winter, peaking in spring or autumn. In the summer, step counts matched the annual average, but durations of activity <3 and >3 METs were, respectively, longer and shorter than in other seasons. These findings have practical implications for those promoting physical activity for older adults.     

Nonformal education for improving educational outcomes for street children and street youth in developing countries: A systematic review

Tens of millions of children and youth (up to 24 years of age) live and work on the streets of developing countries. Most of them are forced to leave formal education. As a potential solution, nonformal education (NFE) interventions have spread worldwide. However, no previous attempt has been made to address the state of evidence regarding effectiveness studies of NFE for street children and youth. This review addresses this gap by conducting the first systematic review concerning the effectiveness of NFE for improving educational outcomes for street children and street youth. The search was conducted in 35 structured electronic databases and numerous organizations and experts were also contacted. The screening of 9,271 titles resulted in the identification of zero prospective effectiveness studies with a counterfactual. Lessons are drawn from the highest quality excluded studies to inform future evaluations that seek to address this knowledge gap. Key Practitioner Message: ● Practitioners should implement comparable intake and monitoring assessments to track changes consistently over time; ● Programs informed by critical pedagogy and empowerment‐based approaches may improve behavioral outcomes; ● Programs that work with street children and street youth should clarify how they identify their target population.     

Econometric analysis of realized volatility and its use in estimating stochastic volatility models

Summary. The availability of intraday data on the prices of speculative assets means that we can use quadratic variation-like measures of activity in financial markets, called realized volatility, to study the stochastic properties of returns. Here, under the assumption of a rather general stochastic volatility model, we derive the moments and the asymptotic distribution of the realized volatility error—the difference between realized volatility and the discretized integrated volatility (which we call actual volatility). These properties can be used to allow us to estimate the parameters of stochastic volatility models without recourse to the use of simulation-intensive methods.     

The simulation of industrial robot systems

This paper describes the GRASP computer aided design system for modelling and evaluating industrial robot workplaces. GRASP satisfies a range of simulation needs within the context of designing, implementing and operating industrial robotic systems. The GRASP software may be used to investigate robots operating by themselves or, more likely, as part of an integrated cell. Facilities within GRASP assist workplace layout, position and velocity evaluations, clash detection and co-ordination between items. A robot library exists and is being extended, and an embryo off-line programming facility has been used under restricted conditions. GRASP has been used to help solve a wide range of practical industrial robot problems and has proved itself technically, and also as an educational tool, by showing how a proposed system would operate. The paper describes the facilities within GRASP.     

How do we capture 15 years of complex and meaningful data about young people's lives?

Abstract

This paper describes the development of a method of data collection, which captures the complexity of living situations, family dynamics and key life events of teenagers. This ‘Life History Calendar’ was adapted from earlier life history calendar methods for a multidisciplinary intergenerational study. The new calendar is able to record details of 15 years of teenage participants’ lives and can be administered to teenagers and their parents to show changes over individual lives and difference between individuals in a cohort. Referring to some preliminary data, we show that the calendar is a practical and effective method of data collection, which will be useful to researchers and practitioners working with young people and their families.     

Integrated OU Processes and Non-Gaussian OU-based Stochastic Volatility Models

Abstract. In this paper, we study the detailed distributional properties of integrated non-Gaussian Ornstein–Uhlenbeck (intOU) processes. Both exact and approximate results are given. We emphasize the study of the tail behaviour of the intOU process. Our results have many potential applications in financial economics, as OU processes are used as models of instantaneous variance in stochastic volatility (SV) models. In this case, an intOU process can be regarded as a model of integrated variance. Hence, the tail behaviour of the intOU process will determine the tail behaviour of returns generated by SV models.     

Precaution and liquidity in the demand for housing

We exploit cross-sectional mortgage data to investigate the importance of liquidity constraints and a precautionary motive in the demand for housing. Households that are not liquidity constrained consume housing services essentially as the life cycle hypothesis suggests but with a significant precautionary component. Households that are liquidity constrained, in terms of not meeting standard loan-to-value or payments-to-income constraints, are similar to unconstrained households in most respects, including the precautionary motive, but they respond somewhat less to fluctuations in their lifetime income - suggesting some influence of bank-induced liquidity constraints. We additionally find, however, that banks enforce liquidity constraints only weakly.