Chartering strategies for shipping companies

This paper describes a model which may be used in the evaluation of the relative effectiveness of policies used in the areas of ship chartering and the switching of combined carriers between the dry cargo market and the tanker market. The policies for chartering and market switching are expressed in the form of ‘desired proportions’ of the fleet operating in a particular charter-mode or a particular market. Graphical illustration of this form of expression of policies can be easily understood, so that alternative policies can be designed with relative ease. The effectiveness of a particular form of policy under various freight market conditions can be determined from the model, the use of which is illustrated by its application to the deployment of the fleet of an hypothetical shipping company. It is assumed that the feedback connection between the company's actions and the marketplace is negligible.     

The reversal small-world experiment

This paper is an attempt to examine and define the world network of a typical individual by discovering how many of his or her acquaintances could be used as first steps in a small-world procedure, and for what reasons. The town and occupation of each target was provided, together with the ethnic background, where this could not be inferred from the name. Starters were instructed in the small-world experiment and asked to write down their choice, amongst the people they knew, for the first link in a potential chain from them to each of 1267 targets. Starters provided information on each choice made (e.g. mother, cousin, friend, acquaintance, etc.) together with the sex of the choice) and the reason that choice had been made. The reason could be in one or more of four categories: something about the location of the target caused the starter to think of his or her choice; the occupation of the target was responsible for the choice; the ethnicity of the target; or some other, unspecified, reason.Six main conclusions may be drawn from the data: (1) A mean of 210 choices per starter account for the “world” (i.e. the 1267 targets). This number is probably an underestimate. Only 35 choices are necessary to account for half the world, however. Of the 210, 95 (45%) were chosen most often for location reasons, 99 (47%) were chosen most often for occupation reasons, and only 7% of the choices were mainly based on ethnicity or other reasons. (2) Choices were mainly friends and acquaintances, with strong cleavage by sex. For any given target, the type of choice used by the majority of starters was a friend or acquaintance, and not family. For any given target, the most likely sex of the choice (i.e. over all starters) can be predicted accurately on 82% of occasions. This sex tends to be male, unless both starter and target are female, or if the target has a low-status occupation. Additionally, any given starter is most likely to pick a male choice for any target, except for the female starter-female target combination, when female choices are more likely. This was correct on 64% of occasions. (3) Location was the usual reason for choice (out of the four categories), with occupation second, and ethnicity or other reasons rarely used. This most popular reason for choice may be correctly predicted for any given target 81% of the time. (4) The decision as to which choice was made appears to depend primarily on the occupation of the target, and secondly on the distance (near/far) from Morgantown, West Virginia, where the experiment took place. (5) The expression “having one's man in …” can be partially quantified. We may define a choice to “handle” a state in the U.S. if he or she was chosen for two-thirds or more of the targets in that state for which choices were made on the basis of location. Then, for any starter, on average, half the states are each handled by a single choice. (6) The accuracy of starters' recall about their networks is low, in the sense that their recall is incorrect more often than it is correct (i.e. their recall could not be put to any other use with any reliability). This confirms previous experiments on informant accuracy.     

Census enumeration in remote Australia: Issues for aboriginal data analysis

Given the crucial role played by census data in informing economic and social policies directed at the Aboriginal population in remote areas, some assessment of the quality of remote area data is required as these are derived from enumeration procedures which differ fundamentally from the standard approach employed in the census. This paper discusses the remote area census enumeration strategy employed by the Australian Bureau of Statistics (ABS), with a particular focus on the Northern Territory, and highlights possible implications for the interpretation of census counts and census characteristics.     

Adaptation to Retirement: Role Changes and Psychological Resources

In this review, the influence of social and work roles are incorporated into a model of retirement adjustment, along with two psychological moderators that may aid the retirement transition. These psychological resources, locus of control and retirement self-efficacy, are those behavioral predispositions that would lead one to engage in proactive strategies for mastering the role changes inherent in the retirement transition. The implications of social and work-related role changes and psychological resources for retirement planning and adjustment are discussed.     

Statistical approaches for the reliability of structural designs

The Construction Industry Research and Information Association (CIRIA) has produced some guidelines for the assessment of the reliability of components and/or structures. The methods of analysis suggested by these guidelines are far from adequate and, in certain cases, contain some imperfections. In this paper, some of the weaknesses of the guidelines are identified. The shortcomings are mainly in the ease of calculations and the feasibility of the assumptions which are imposed. Three alternative methods aimed at tackling some of the weaknesses are introduced. A simulation study is used to compare these methods.