112,980 research outputs found
Blocking Java Applets at the Firewall
This paper explores the problem of protecting a site on the Internet against hostile external Java applets while allowing trusted internal applets to run. With careful implementation, a site can be made resistant to current Java security weaknesses as well as those yet to be discovered. In addition, we describe a new attack on certain sophisticated firewalls that is most effectively realized as a Java applet
Deep Space Network information system architecture study
The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control
The battle between standards: TCP/IP vs OSI victory through path dependency or by quality?
Between the end of the 1970s and 1994 a fierce competition existed between two possible standards, TCP/IP and OSI, to solve the problem of interoperability of computer networks. Around 1994 it became evident that TCP/IP and not OSI had become the dominant standard. We specifically deal with the question whether the current dominance of the TCP/IP standard is the result of third degree path dependency or of choices based on assessments of it being technical-economically superior to the OSI standard and protocols
A Fault Tolerant, Dynamic and Low Latency BDII Architecture for Grids
The current BDII model relies on information gathering from agents that run
on each core node of a Grid. This information is then published into a Grid
wide information resource known as Top BDII. The Top level BDIIs are updated
typically in cycles of a few minutes each. A new BDDI architecture is proposed
and described in this paper based on the hypothesis that only a few attribute
values change in each BDDI information cycle and consequently it may not be
necessary to update each parameter in a cycle. It has been demonstrated that
significant performance gains can be achieved by exchanging only the
information about records that changed during a cycle. Our investigations have
led us to implement a low latency and fault tolerant BDII system that involves
only minimal data transfer and facilitates secure transactions in a Grid
environment.Comment: 18 pages; 10 figures; 4 table
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