THE DATACON MASTER -RENOVATION OF A DATACON FIELD BUS COMMUNICATIONS SYSTEM FOR ACCELERATOR CONTROL *

Abstract The Datacon Master (V110) is a custom-designed VMEbus SBC event driven serial communications engine featuring a superscaler RISC 32-bit Intel i960 CPU. The V110 and a commercial VMEbus host CPU running vxWorks with an Ethernet LAN connecting UNIX workstation consoles, make up the real time control system. Five V110 and three host CPUs will replace and upgrade PDP10 and PDP8 Datacon AGS front end computers. Five V110s will support twenty Datacon field busses with some 2600 devices. The V110 firmware is written in C. An accelerator event time link interface and µS timestamp are built-in. Each Datacon field bus supports up to 256 devices on a multidrop RG62A/U coaxial cable with up to 2000 feet between repeaters. Each V110 drives up to four full Datacon field busses at 1 MHz bandwidth

Course Credit Accrual and Dropping Out of High School, by Student Characteristics.

This Statistics in Brief uses data from the Education Longitudinal Study of 2002 (ELS:2002) to examine the number of credits earned by high school students and the relationship between course credit accrual and dropping out. Findings indicate that high school dropouts earned fewer credits than did on-time graduates within each year of high school, and the cumulative course credit accrual gap increased with each subsequent year. The pattern of dropouts earning fewer credits than on-time graduates remained across all examined student and school characteristics (student sex, race/ethnicity, and socioeconomic status, school location, and sophomore class size). However, the size of the cumulative course credit accrual gap between on-time graduates and dropouts varied within academic years for males versus females, Blacks and Hispanics versus Whites, and students attending city high schools versus students attending suburban, town, and rural high schools. For example, the cumulative gap between on-time graduates and 12th-grade dropouts in 2001-02 and 2002-03 was larger for males than for females, indicating that male 12th-grade dropouts were further behind their on-time peers in cumulative course credits accrued than were female 12th-grade dropouts

Racial School Segregation and the Transition to College

Prior studies generally find that attending black-segregated schools is detrimental across a range of academic outcomes, but much research on the causes and consequences of school segregation rely on single time-point measures of student exposure. Demographic shifts and educational policy changes in the last two decades increase the possibility that students experience different racial compositions throughout their educational careers and underscore the need to better understand how different patterns of exposure over time affect student outcomes. This dissertation identifies distinct trajectories of exposure to racially segregated schools for a national sample of a student cohort, examines factors that predict trajectory membership, and estimates the consequences of different patterns of exposure on postsecondary college outcomes. Using data from the National Longitudinal Survey of Youth (1997), Common Core Data, and the Private School Survey, I find that the vast majority of students belong to stable exposure trajectories, either consistently exposed or consistently non-exposed to black-segregated schools; a smaller proportion of students belong to dynamic trajectories, either exiting or entering black-segregated schools. The pattern of racial change (or stability) at the school level, as opposed to student school mobility, is the primary predictor of a student’s own segregation exposure trajectory. I find a key difference in college outcomes along different temporal dimensions of segregation exposure, particularly that exposure later in high school, but not early in middle school, is detrimental to college enrollment and completion. These findings provide direction for educational policy and motivate future research to uncover the mechanisms responsible

The Fragmented Evolution of Racial Integration since the Civil Rights Movement

The Civil Rights Movement ushered in a new era of racial tolerance. One reflection of this tolerance is the diminishing occurrence of White flight: in 2010, only one in one hundred neighborhoods is all-White. Although some have declared the "end of segregation" based on this news, I document how ``integrated'' neighborhoods are actually fragmented into many different types of racial change. This means that some nominally integrated neighborhoods have less in common with one another than they do with adjacent segregated neighborhoods. Others, however, appear to maintain stable integration across many decades. I consider the historical, geographic, and demographic factors that can help explain how neighborhoods end up following different trajectories. I argue that this fragmented integration should cause us to think more deeply about what integration means and make policies that address the foundation of spatial inequality in the post-Civil Rights Era

Process control for the ISABELLE system

A low cost, highly reliable control system has been developed for use in the radiation environment of the ISABELLE ring. The Ultra-High Vacuum installation will consist of approximately 1500 stations - each having 8 readbacks, 4 on-off operations and 4 special functions - distributed over 2.5 mills. The paper will describe a multidrop party line system in which a ..mu..p based controller located in a protected environment communicates with up to 25 vacuum stations. All the ..mu..p controllers will be linked via the ISABELLE data highway. Mechanical, electronic and software aspects of the system are discussed and performance data from our First Cell model are presented

Expectations and Reports of Homework for Public School Students in the First, Third, and Fifth Grades.

This brief uses data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 (ECLS-K) to examine (1) the amount of time that students’ public school teachers expected them to spend on reading/language arts and mathematics homework in first, third, and fifth grades; and (2) reports from parents of public school children of how often their children did homework at home in the first, third, and fifth grades. Teachers' expectations are reported by the percentage of minority students in the student's school and parents' reports are reported by the child's race/ethnicity. The findings indicate that the amount of reading and mathematics homework that students' teachers expected them to complete on a typical evening generally increased from first grade to fifth grade. In both subjects and in all grades, differences were found by the minority enrollment of the school. Children in schools with higher percentages of minority students had teachers who expected more homework on a typical evening, whereas generally children in lower minority schools had teachers who expected less homework. In addition, in all three grades, larger percentages of Black, Asian, and Hispanic children than White children had parents who reported that their child did homework five or more times a week

RELWAY: a process data highway system optimized for accelerators

The command/control scheme for the Isabelle accelerator, specifically the process data highway are discussed. (GHT)