Two-stage proportionate flexible flow shop to minimize the makespan

We consider a two-stage flexible flow shop problem with a single machine at one stage and m identical machines at the other stage, where the processing times of each job at both stages are identical. The objective is to minimize the makespan. We describe some optimality conditions and show that the problem is NP-hard when m is fixed. Finally, we present an approximation algorithm that has a worst-case performance ratio of $\frac{5}{4}$ for m=2 and $\frac{\sqrt{1+m^{2}}+1+m}{2m}$ for m≥3.     

Active Ageing Index in Korea – Comparison with China and EU countries

The evidence‐based policymaking relies on the use and robustness of the available data. Many conceptual and operational difficulties restrict this process, not least in making use of evidence to identify policy priorities. The Active Ageing Index (AAI), developed originally for the 28 European Union countries, offers a strong motivation in this respect. This paper reports on the development of the AAI for Korea, a country where speed and level of population aging is among the highest in the world. Drawing on the comparative analysis of the AAI results for Korea, China, and European countries, we find that Korea's AAI (35.3) is higher than the average of the AAI for all EU countries (33.9) but lower than China (37.3). Fitting Korea into the overall ranking with the EU countries and China (ranked 7), Korea is ranked 11, just behind Germany (10). The AAI results in Korea show that the employment domain performs extremely well compared with the EU countries, but other domains, especially “Social participation” and “Independent, healthy and secure living,” are achieving less favorable outcomes. High employment among the current cohorts of older workers in Korea can be attributed largely to the constraints of low pension income status.     

Static Numbers to Dynamic Statistics: Designing a Policy-Friendly Social Policy Indicator Framework

In line with the economic crisis and rapid socio-demographic changes, the interest in ??social?? and ??well-being?? indicators has been revived. Social indicator movements of the 1960s resulted in the establishment of social indicator statistical frameworks; that legacy has remained intact in many national governments and international organisations. With this background, this research examines whether existing social indicator frameworks are valid and effective enough to address increasingly complex social issues. The authors argue that, despite some improvements, current social indicators fail to provide an effective framework and tool for measuring the progress of social welfare and also for developing or reforming social policy to cope with newly emerging social problems. While proposing a new social indicator framework based on the Organisation for Economic Co-operation and Development??s pressure-state-response (PSR) model, the paper argues that the new framework should be more than displaying static numbers but should use dynamic statistics revealing causes and effects and shedding light on social and policy changes.     

Bootstrap confidence regions computed from autoregressions of arbitrary order

Given a linear time series, e.g. an autoregression of infinite order, we may construct a finite order approximation and use that as the basis for confidence regions. The sieve or autoregressive bootstrap, as this method is often called, is generally seen as a competitor with the better-understood block bootstrap approach. However, in the present paper we argue that, for linear time series, the sieve bootstrap has significantly better performance than blocking methods and offers a wider range of opportunities. In particular, since it does not corrupt second-order properties then it may be used in a double-bootstrap form, with the second bootstrap application being employed to calibrate a basic percentile method confidence interval. This approach confers second-order accuracy without the need to estimate variance. That offers substantial benefits, since variances of statistics based on time series can be difficult to estimate reliably, and—partly because of the relatively small amount of information contained in a dependent process—are notorious for causing problems when used to Studentize. Other advantages of the sieve bootstrap include considerably greater robustness against variations in the choice of the tuning parameter, here equal to the autoregressive order, and the fact that, in contradistinction to the case of the block bootstrap, the percentile t version of the sieve bootstrap may be based on the 'raw' estimator of standard error. In the process of establishing these properties we show that the sieve bootstrap is second order correct.     

Testing non-nested log-linear models with pseudo estimator

As the number of random variables for the categorical data increases, the possible number of log-linear models which can be fitted to the data increases rapidly, so that various model selection methods are developed. However, we often found that some models chosen by different selection criteria do not coincide. In this paper, we propose a comparison method to test the final models which are non-nested. The statistic of Cox (1961, 1962) is applied to log-linear models for testing non-nested models, and the Kullback-Leibler measure of closeness (Pesaran 1987) is explored. In log-linear models, pseudo estimators for the expectation and the variance of Cox's statistic are not only derived but also shown to be consistent estimators.     

Racial differences in retirement income: the roles of public and private income sources

Despite great overall improvement in the elderly's economic status over the past two decades, minority elders still comprise the poorest population group of all. Nonetheless, the income security of minority elders has not been given special attention in the scrutiny in recent years of the size and the future of various federal programs affecting older persons. Based on data from the 1971, 1981, and 1991 public-use data tapes of the Current Population Survey, the racial difference in income status of the elderly and the role of Social Security and Supplemental Security income versus that of income from private sources are analyzed in terms of how income inequality among races is ameliorated or escalated. The findings show that racial/ethnic differences in income status increased between 1970 and 1990. The findings also confirm that, for both elderly singles and couples, Social Security is the most important income source. Without it, poverty rates among elderly black couples, for example, would have increased by as much as 48.5 percentage points in 1990. Policies that would help improve the income status of the low-income elderly are discussed.     

The Impact of Authority Relations and Feedback Delivery Method on Performance

ABSTRACT

The proliferation of technology has been changing feedback delivery methods in organizations. However, the effectiveness of feedback delivery methods can vary depending on social dynamics (e.g., authority relations) in the organization. The current study was designed to examine the impact of authority relations and feedback delivery methods on performance. A total of 120 participants were recruited to work on a simulated cell-phone assembly task and were exposed to one of the four feedback conditions: (a) authority figure with face-to-face feedback, (b) authority figure with e-mail feedback, (c) non-authority figure with face-to-face feedback, and (d) non-authority figure with e-mail feedback. Results showed that while both feedback delivery methods resulted in high performance with the presence of an authority figure, only face-to-face feedback resulted in high performance with a non-authority figure. Practical considerations for effective feedback delivery methods in relation to authority figures are also discussed.     

On the leadership function of self-sacrifice

This paper describes the leadership function of self-sacrifice in organizational settings using a multiple-level model of leadership. It explores why self-sacrificial behaviors would arise in organizational settings and what would be the effects on followers if a leader exhibits self-sacrificial behaviors. It is proposed that self-sacrificial leadership will facilitate individual and organizational adaptations to changing environments and that followers will attribute charisma and legitimacy to a self-sacrificial leader and intend to reciprocate.