Dealing with Timing and Synchronization in Opportunities for Joint Activity Participation. 公共活动参与机会中实时性与同步性处理

The ability of people to access opportunities offered by the built environment is circumscribed by various sets of space–time constraints, including the requirements to meet other persons at particular times and places to undertake activities together. While models of space–time accessibility recognize that joint activities may constrain the performance of activities in space and time, their specifications do not explicitly acknowledge the opportunities that individuals of a group have for joint activity participation. Therefore, this article focuses on joint activity participation and argues that collective activity decisions are the outcome of a complex process involving various aspects of timing, synchronization, and social hierarchy. The utility‐theoretic model proposed here quantifies the extent to which opportunities can be jointly accessed by a particular group of people within a specific time period. Central to the approach are three key variables: the attractiveness of an opportunity, the time available for activity participation, and the travel time to an activity location. Because of the multiperson character of joint activities, the determination of these variables is subject to individual preferences, privileges, and power differentials within a group. Specific attention is given to how time‐of‐day and synchronization effects influence the opportunities accessible to a group of individuals. The impact of these factors on joint accessibility is illustrated by a real‐world example of an everyday rendezvous scenario. The outcomes of a simulation exercise suggest that time‐of‐day and synchronization effects significantly affect the benefits that can be gained from opportunities for joint activities.     

Kings and commoners at Copan: Isotopic evidence for origins and movement in the Classic Maya period

Eight human interments were excavated in the 1990s beneath the Acropolis at the Classic Maya site of Copan in Honduras, which was the capital of a Maya kingdom from ca. AD 400 to 800. These human remains come from both royal tombs and less elaborate burials dating to the early part of this period and lie deep in the accumulated architectural layers of the Acropolis. We present a brief summary of the context, contents, and external links represented by these interments. Several lines of evidence point to connections between early Copan and Teotihuacan in the Central Highlands of Mexico, and Tikal in the central Maya lowlands of the Petén in Guatemala.     

Australia–Japan economic relations: ten years after the NARA Treaty

The NARA Treaty looked to a strengthened Australia–Japan relationship, which foreign ministers of both countries celebrated this year. Events of the mid 1980s, however, demonstrated how an adverse turn in economic circumstances can stress even a strong bilateral relationship. The two countries were then at opposite points in their economic cycles, Japan almost too successful, with the high yen putting pressure on Japan's export industries, steel in particular. Seeking to reduce costs, the steel mills transferred pressure to their Australian suppliers of coal and iron ore, through reductions in prices and volumes. This was unwelcome to an Australian government coping with a recession and worried about balance of payments and unemployment, and led to concerns about equal treatment. Although the minerals trade returned to normal relatively quickly, ambitious investment projects aimed at enhancing the economic relationship did not materialise.     

A NOTE ON ADDED INFORMATION IN THE RAS PROCEDURE: REEXAMINATION OF SOME EVIDENCE

ABSTRACT.  An example in Miernyk (1977) presented a rather counterintuitive result, namely, that introducing accurate exogenous information into an RAS matrix estimating procedure could lead to an estimate that was worse than one generated by RAS using no exogenous information at all. This became an oft-cited black mark against RAS. Miller and Blair (1985) included a different (and small) illustration of the same possibility. It was recently pointed out by one of us that the Miller–Blair numerical results are wrong. For that reason, we decided to reexamine all the empirical evidence we could find on the subject. While figures in both Miernyk and Miller–Blair appear to be wrong, more recent published examples seem to have it right. In short, it is possible to identify examples in which additional (correct) information leads to poorer RAS estimates, at least under several fairly common metrics for comparing "closeness" of matrices. However, the overwhelming majority of the evidence is to the contrary. As a general rule, introduction of accurate exogenous information into RAS improves the resulting estimates, and counterexamples should probably not be taken too seriously.