A new visibility instrument, the forward scatter visibility meter, has been developed. This report describes the development of the instrument, including the various field tests. Some thirty instruments have been operationally deployed in a network of automatic weather stations near L.G. Hanscom Field in Bedford, Mass. Comparisons between field instruments and transmissometers yield differences of about plus or minus 19 percent. Comparisons with visual observations show differences of plus or minus 34 percent and greater. Analyses of individual cases uncovered difficulties with the response time of observers and with ability to diagnose spatially varying visibility. The accuracy of visibility measurements is assessed and the report concludes by looking at the future of visibility instruments. (Author).

Welcome to Social City! Follow Brian as he navigates his way through Social City, experiencing problems of different sizes. Using the Problem/Reaction Meter, he and his friend Ellie gauge the size of each problem and choose a reaction on the same level. This book makes abstract social-emotional concepts concrete for children who overreact to little problems, helping them realize the importance of matching the size of their reaction to the size of the problem. Visuals and lessons are included to help children further understand this concept and apply it to their own lives. This second book of the Social City series is a fun and effective resource for teachers, speech language pathologists, counselors and parents to use with preschool and elementary-aged children.

In the past decade, the formal theory of specification, verfication and development of real-time programs has grown from work of a few specialized groups to a real "bandwagon". Many eminent research groups have shifted their interests in this direction. Consequently, research in real-time is now entering established research areas in formal methods, such as process algebra, temporal logic, and model checking. This volume contains the proceedings of a workshop dedicated to the theory of real-time with the purpose of stepping back and viewing the results achieved as well as considering the directions of ongoing research. The volume gives a representative picture of what is going on in the field worldwide, presented by eminent, active researchers. The material in the volume was prepared by the authors after the workshop took place and reflects the results of the workshop discussions.

This book explores the option of building on symbolizing, modeling and tool use as personally meaningful activities of students. It discusses the dimension of setting: varying from the study of informal, spontaneous activity of students, to an explicit focus on instructional design, and goals and effects of instruction; and the dimension of the theoretical framework of the researcher: varying from constructivism, to activity theory, cognitive psychology and instructional-design theory.