Optimal maintenance and replacement of extraction machinery

This paper considers a problem of optimal preventive maintenance and replacement schedule of equipment devoted to extracting resources from known deposits. Typical examples are oil drills, mine shovels, etc. At most one replacement of the existing machinery by a new one is allowed. The problem is formulated as an optimal control problem subject to the state constraint that the remaining deposit at any given time is nonnegative. We show that the optimal preventive maintenance, production rates, and the replacement and salvage times of the existing machinery and the new one, if required, can be obtained by solving sequentially a series of free-end-point optimal control problems. Moreover, an algorithm based on this result is developed and used to solve two illustrative examples.     

Interval Time Series Analysis with an Application to the Sterling-Dollar Exchange Rate

Traditional econometrics has long employed ＂points＂ to measure time series data. In real life situations, however, it suffers the loss of volatility information, since many variables are bounded by intervals in a given period. To address this issue, this paper provides a new methodology for interval time series analysis. The concept of ＂interval stochastic process＂ is formally defined as a counterpart of ＂stochastic process＂ in point-based econometrics. The authors introduce the concepts of interval stationarity, interval statistics （including interval mean, interval variance, etc.） and propose an interval linear model to investigate the dynamic relationships between interval processes. A new interval-based optimization approach for estimation is proposed, and corresponding evaluation criteria are derived. To demonstrate that the new interval method provides valid results, an empirical example on the sterling-dollar exchange rate is presented.     

Immigration, emigration and the ageing of the overseas-born population in the United Kingdom

This article uses data from the 1971 and 2001 Censuses, the 1999-2003 Labour Force Survey and the 1977 to 2002 International Passenger Survey to investigate the migration processes contributing to the age structure and ageing of the UK's overseas-born population. Overall almost half of recent decades' immigrants to the UK emigrate again within five years of arrival, but with large variation by overseas country of birth. Between half and two thirds of the immigrants born in the continental European Union, North America and Oceania emigrate again within five years, while 15 per cent of those born in the Indian subcontinent do so. Significant cumulative emigration more than five years after arrival is seen among earlier immigrants from the Indian subcontinent, the Caribbean Commonwealth and Europe. Large country-of-origin variations in the ratio of pension-age population to working-age population primarily reflect the country composition of immigration streams 30 or more years before.     

ORGANIZATIONAL LEARNING AND VENDOR SUPPORT QUALITY BY THE USAGE OF APPLICATION SOFTWARE PACKAGES： A STUDY OF ASIAN ENTREPRENEURS

In this paper we study how organizational learning impacts organizational behavior, and howvendor support quality enhances product adoption and usage behavior.These constructs were verifiedusing Application Software Packages(ASP)-a prewritten, precoded, commercially available set ofprograms that eliminates the need for individuals or organizations to write their own softwareprograms for certain functions. The relationship between ASP usage, usage outcomes and useprocesses were also investigated. Two hundred and ninety-five Chinese, Indian, and Malayentrepreneurships were studied. It was found that usage outcome strongly determines usage, while useprocess has only an indirect relationship (via outcome) on usage. The impact of organizational learningand vendor service quality on usage, usage outcome, and use process were robust. Theoretical andpractical implications of the research are discussed.     

Simultaneous care for parents and care for children among mid-life British women and men

This article investigates care provided to parents and parents-in-law by mid-life adults with dependent children at home. Data from the General Household Survey are used first to estimate the prevalence of this 'two-way' care over the past decade, and second to develop forecasts of two-way care for a generation of women who have just finished their childbearing years. Having a higher education qualification is associated with later ages both of caring for parents and of having children at home. Increasingly late first childbearing, however, points towards a potentially greater caring 'squeeze' for higher-qualified women, with a little over 1 in 10 at age 45 projected to be caring for a parent while still having a child under 18 in the household.     

An interval method for studying the relationship between the Australian dollar exchange rate and the gold price

This paper proposes an interval method to explore the relationship between the exchange rate of Australian dollar against US dollar and the gold price,using weekly,monthly and quarterly data.With the interval method,interval sample data are formed to present the volatility of variables. The ILS approach is extended to multi-model estimation and the computational schemes are provided. The empirical evidence suggests that the ILS estimates well characterize how the exchange rate relates to the gold price,both in the long-run and short-run.The comparison between the interval and point methods indicates that the difference between the OLS and the ILS estimates is increasing from weekly data to quarterly data,since the lowest frequency point data lost the most information of volatility.     

Childbearing outside marriage in western Europe

Across most European states in recent decades there have been significant increases in childbearing outside marriage. This article examines the extent to which women have their first child in one of four settings: prior to any partnership; in their first cohabiting partnership; in first marriage; and after a first partnership. Temporal changes in these behaviours and variation according to background characteristics of the women are also examined. For the women who had a child outside any partnership, we examine the extent to which they go on to form partnerships and how long after the birth this happens. For those who had their first child within a cohabiting union, we examine the extent to which they marry and how long after the birth this occurs. Finally, we investigate whether children born within cohabiting unions that do and do not convert into marriages are more or less likely than those born within marriage to see their parents separate.     

Birds of a Feather Protest Together: Theorizing Self-Organizing Political Protests with Flock Theory

The current research theorizes decentralized and self-organized political protests via flock theory (Rosen 2002), a theory of emergent self-organization in communicative human interaction. Flock theory draws from a theoretical basis of emergence and self-organizing systems, and is presented as a theory of decentralized communication structures. Focusing on the optimization of decentralized networks and roadmap based coordination of organizationally homopholous foci; the current theory poses a model of human interaction that captures the potentially egalitarian effects of cooperative evolution and collective action. Case studies of two separate decentralized political protests against Korean government and FARC are offered as evidences of such phenomena.