Performance evaluation of two multiple-access protocols

A real-time, microprocessor-based simulator was designed to study the packet transmission of voice on a broadcast type local area network, based on the CSMA/CD and Hymap multiple-access protocols. The speech quality is evaluated subjectively. A packetization-frozen protocol is used to eliminate the successive collisions due to possible synchronization of packet generation among stations. The variance of the network delay is bounded by discarding packets which have not been transmitted within a certain amount of time. Smooth speech output can be obtained by introducing additional buffer delay at the receiver.     

Mechanisms of normal and abnormal neurulation: evidence from embryo culture studies

In this paper we estimate the size of several categories of "Israeli" immigrants in the United States. According to the 1990 U.S. census, there were about 95,000 Israeli-born immigrants in the United States in that year. Using the language and ancestry information available in the Public Use Microdata Sample (PUMS) of the 1990 census, we estimate that of this total, about 80,000 are Jews and 15,000 are Palestinian Arabs born in Israel. In addition to the Israeli-born, we present a range for the number of Jewish immigrants from Israel who are not Israeli-born (about 30,000-56,000). Thus our estimate for the total number of Jewish immigrants from Israel in the United States in 1990 is between 110,000 and 135,000. Fertility information available in the PUMS, also enable us to provide estimates for the number of second-generation Israelis in the United States in the 1990 (about 42,000). Finally, using both the 1980 and 1990 PUMS, we provide estimates for the rate of return migration among Israeli-born Jewish immigrants in the United States.