Ethnic capital and intergenerational transmission of educational attainment

This paper studies the role of ethnicity in the intergenerational transmission of educational attainment within the framework outlined by Borjas (Quarterly Journal of Economics, 1992, 107(1), 123-150). Relying on heteroskedasticity to identify parameters in the presence of endogenous regressors, I find evidence that the ordinary least squares estimates of the effect of ethnic capital on intergenerational transmission of education are biased upwards due to the transfer of unobserved ability. I also find that, while the role of parental capital has declined over time, ethnic capital has a relatively constant effect on intergenerational transmission of educational attainment

Switching systems for integrated communication

At the Heinrich-Hertz-Institut an experimental system is being developed for testing the functioning and technology of integrated digital switching units connected by glass fiber networks. This experimental system includes many switching components and exchange methods. This paper presents the concept and operation of these components. The procedures of system operation in the digital network is described as well as concepts for maintenance and improvement of the reliability. Finally a monitoring system is described for the digital network. An efficient multiprocessor system is designed for rate registration, function monitoring, remote control of components and protection against manipulation

Network architectures for optical burst switching in "broadcast and select" switching

The paper describes the use of optical semiconductor amplifiers (SOA) and explains "optical burst switching" (OBS) as situations where several Internet protocol packets are aggregated electronically for broadband Internet applications. It presents calculations and results of a simulation relating to scalability of optical switching nodes, and examines signal quality and error rate due to noise in semiconductor amplifiers and optical switches, and refers to optical wavelength conversion. The paper notes that optical burst switching should be achievable within 1 microsecond, and refers to avoidance of switching conflicts, by using intermediate burst storage, and also deals with multicast applications, used for conference connections

Einordnung des Breitband-Kommunikations-Systems mit optischen Kanaelen in den internationalen Stand der Entwicklung optischer Breitbandnetze

TIB: RA 361 (223) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

OFDM-LAN mit optischer Filtertechnik. Teilprojekte: 'OFDM-LAN/MAN' und 'Optisch transparente Zusammenschaltung von OFDM-Inselnetzen' Abschlussbericht

SIGLEAvailable from TIB Hannover: DtF QN1(87,38) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman