Analysis of automatic network management controls

The performance response of circuit-switched networks with stored program control exchanges is analyzed under nonstationary traffic conditions. Models of real time traffic measurements and dynamic flows in such networks are developed. A framework for analysis and design of state-dependent routing and flow control algorithms is provided based on concepts of various traffic measurements and different patterns of traffic nonhomogeneity. It is indicated that global performance objectives can be obtained by means of the state-dependent shortest route algorithms. Issues relevant to an implementation of different traffic control techniques are discussed. An example routing scheme is introduced and compared with known procedures     

Engineering education in Poland

Basic engineering education in Poland is described. The factors effecting education which are specific to that country, including its political situation and the efforts of the academic community during the last several decades to keep in touch with the global flow of people and information, are emphasized. The basic structure of the Polish educational system is discussed and illustrated with several statistics. The decentralization of the academic system is discussed, along with obstacles to further progress. The evolution of curricula for students of telecommunications is analyzed, and the aid of the European Community (EC) in restructuring and modernizing Polish universities is presented. Some comments on continuing education are made     

Relations of changes in coronary disease rates and changes in risk factor levels: methodological issues and a practical example

One of the main hypotheses of the World Health Organization (WHO) MONICA Project is that trends in the major coronary disease risk factors are related to trends in rates of fatal and non-fatal coronary disease events. The units of study are populations rather than individuals. The WHO MONICA Project involves continuous monitoring of all coronary disease events in the populations over a 10-year period and periodic risk factor surveys in random samples of the same populations. Estimation of associations between average annual changes in mortality and risk factor levels is illustrated with the use of data from a subset of MONICA centers. Crude estimates of regression coefficients are compared with estimates obtained by weighting for standard errors in both the outcome and explanatory variables. The results show that the strength of association may be either underestimated or overestimated if these errors are not taken into account.