The effects of different choices of order for autoregressive approximation on the Gaussian likelihood estimates for ARMA models

This paper investigates, by means of Monte Carlo simulation, the effects of different choices of order for autoregressive approximation on the fully efficient parameter estimates for autoregressive moving average models. Four order selection criteria, AIC, BIC, HQ and PKK, were compared and different model structures with varying sample sizes were used to contrast the performance of the criteria. Some asymptotic results which provide a useful guide for assessing the performance of these criteria are presented. The results of this comparison show that there are marked differences in the accuracy implied using these alternative criteria in small sample situations and that it is preferable to apply BIC criterion, which leads to greater precision of Gaussian likelihood estimates, in such cases. Implications of the findings of this study for the estimation of time series models are highlighted.     

River basin planning as a strategy for rural development in Nigeria

River basin planning has existed in one form or another since the third millenium B.C. when some of the earliest civilizations evolved in the great drainage basins of Mesopotamia, Egypt and north-west India. It has, however, undergone several modifications before finally culminating in the comprehensive planning for simultaneous development of all resources of a river basin.The idea of river basin planning was first mooted in Nigeria by the Food and Agriculture Organization in the late 1960s. Beginning in the early 1970s, the Federal government of Nigeria also came to the belief that river basin planning could play a significant role in the country's development. At the height of the ‘oil boom’ in 1976 and with the incipient manifestation of structural problems in the national economy, the government took a giant step in river basin planning by the establishment of 11 river basin development authorities. River basin planning is viewed as a ‘new approach’ to rural development and has involved more substantial capital outlay than all the other rural programmes combined.This paper examines the implementation and impact of these projects, which are large-scale and capital intensive, and which may be incompatible with a strategy aimed at improving the lot of the peasant farmers. The projects have wrought havoc on the prevailing rural economy and social-economic structures. Even if they were to achieve the primary objective of increasing rural productivity, this may be at a great cost to the rural populace and the environment.Perhaps more important is that river basin planning has the potential of substituting one form of dependency for another (food importation being substituted for the importation of fertilizer, pesticides, herbicides, equipment, machines and foreign experts). The projects are thus benefiting a powerful combination of interests comprising local and foreign contractors, land speculators, bureaucrats, rural elites and incipient capitalist farmers who have not borne any losses in the process of implementation.     

Toward a reappraisal of social indicators for housing in developing nations

The need for social indicators to monitor and evaluate progress in the achievement of certain predetermined goals is now very evident. However, the design and construction of these indiactors still leave much to be desired. This paper analyzes the application of social indicators for housing in the context of the developing nations. The problem of changing standards of acceptable housing over time and the different images and needs of the diverse inhabitants bring the validity of present indicators for housing into question and at least, point out the need for talking social and cultural variables into consideration.     

Quality of life and city size: An exploratory study of Nigeria

This paper examines the variations in the quality of life at the relatively neglected inter-urban scale in a developing nation. Based on a sample survey of 3800 heads of households in Nigerian cities ranked into three categories: large, medium and small, the study found that level-of-living is related to city size, with the residents of large cities having a higher quality of life than those in the medium and small cities.     

The effects of cyclic queues on the balance of flow lines

This paper considers a flow line with different numbers of parallel machines at each stage and discusses findings regarding the effect of cyclic queues of containers on line balance. Three types of containers for holding work-in-process following different routes are stored in the cyclic queues. The degree of line imbalance is measured by the level of starving and blocking delays occurring through the line. Stage utilization rates are taken as the measure of performance. The structure of the flow line, which occurs in the cotton spinning industry, and some features of the simulation model are also presented.     

Homosexuality and heterosexism: views from academics in the helping professions

Summary This study describes and analyses attitudes towards homosexualityamong faculty in departments of three helping professions: socialwork, psychology and education. The sample consists of 235 facultymembers in the five main universities in Israel. Out of 849questionnaires that were sent to all faculty members of therelevant departments of social work, psychology and education,103 were completed and returned from social work, 56 from psychologyand 76 from education, representing a 27.7 per cent total responserate. The instrument used was the Index of Homophobia (IHP)(Hudson and Ricketts, 1980) in addition to professional backgroundand demographic information. Findings show that, overall, membersof academic departments of the helping professions present 'low-gradehomophobic' attitudes (Hudson and Ricketts, 1980). Statisticallysignificant differences surfaced among the three departments,with faculty members in schools of education emerging as mosthomophobic, followed by social work and psychology. Severalexplanations are put forward in an attempt to account for suchdifferences, including the theoretical framework of marginality,the variables traditionally associated with homophobia, andprofessional training.     

Measurement of changes: What criteria do we adopt?

Many changes in industrial working methods are now under discussion which are not easily evaluated and management is concerned about the probable return from investing in these methods. It is proposed that, whilst it is clear that improving work performance is a benefit, it is also of benefit to achieve changes in attitudes which correlate more closely with the objectives and state of the enterprise. Increased agreement in this respect is stated to lead to increased stability for the production process as there is less likelihood of disruption of output due to inappropriate decisions and actions. Since the loss due to various forms of interruption in output can be assessed it is described how the benefit of attitude change might thus be measured. A model for the relationships relevant to ergonomic and behavioural science changes in industry is given and its potential is illustrated by examples.     

Stable spectral factorization with applications to the estimation of time series models

A method for generating a miniphase and inveitible spectral factor from an unstable v × v full rank polynomial matrix is proposed. The zeros inside the unit circle are reflected through the boundary |z|=1 using closed form algebraic manipulations. Also included in the procedure is a technique foi determining the stability of a polynomial operator that does not require the explicit construction of the determinant al equation. Application of the technique is illustrated and the implementation of the method in the statistical context of system estimation is discussed.