Replacing the Ethernet access mechanism with the real-time access mechanism of Twentenet

The way in which a Local Area Network access mechanism (Medium Access Control protocol) designed for a specific type of physical service can be used on top of another type of physical service is discussed using a particular example. In the example, an Ethernet physical layer is used to provide service to the Twentenet real-time access mechanism. Relevant Ethernet and Twentenet concepts are explained, the approach taken is introduced, and problems encountered, along with the actual synthesis of both networks, are described

Self-management of lambda-connections in optical networks

This paper presents a new idea for the management of lambda-connections in optical networks. The idea consists of making multi-service optical switches responsible for automatically detecting IP flows at the packet-level, creating lambda-connections for them, and moving them to the optical-level. In addition to that, they are also in charge of tearing down the connections when no longer needed. This new idea is the result of 1 year of research work at the University of Twente (UT) and it is aimed at resulting in a Ph.D. thesis by the end of 4 years of Ph.D. research

What is Community Informatics in Japan? A look at 12 cases

In this paper, we are concerned with the applicability of the concept of Community Informatics (CI) rooted in North American studies to a different context, Japan. Despite the fact that CI is a relatively new filed of study, and Japan???s intensive use of mobile information and communication technologies (ICT) are a common area to find in articles, Japanese CI practices are little known. Among major academic journals that CI scholars appear, there have none of CI articles by Japanese scholars published so far. These draw our attention. We review cases in Japan that apply and adapt information and communications technology (ICT) to local community settings. Applying Williams and Durrance???s framework encompassing community informatics practices, twelve community projects and groups were identified in the study (2007). The projects are categorized into four types based on different conceptions of ICT use in fulfilling community needs and objectives (Williams and Durrance, 2007). These are community groups, organizations, and projects that rely on (1) actual places, i.e., public computing places and cyber cafes, (2) virtual spaces, i.e. , community networks and online resources, (3) some combination of those two, and (4) organic, that is, borne out of community efforts not particularly concerned with technology but which now involve ICT. We chose an opportunistic sampling technique in order to find cases that fit in those four types of CI models. For the very first step, we draw on a small number of articles by Japanese scholars on the utilization of social network service developed by municipal offices using open source software for community development (Toyama, 2007; Shoji, 2007)

DNS zones revisited

Recent research [Pap04b] suggests DNS reliability and performance is not up to the levels it should be due to misconfigurations. This paper checks the configuration of nameserver zones against additional requirements, recommendations and best-practices. It shows that almost one in four domains fails to pass one or more of these checks. During the checks an interesting correlation is established: a higher number of nameservers for a single zone usually decreases reliability and performance instead of increasing both

The Rise of School-Supporting Nonprofits

This paper examines voluntary contributions to public education via charitable school foundations, booster clubs and PTAs/PTOs as an alternative to local revenues generated via the property tax. We employ panel data on school-supporting charities with national coverage from 1995 to 2010, which we geocode and match to school districts. We first document the meteoric rise of school-supporting nonprofits during this panel, and then estimate a series of regression models including both reduced-form and fixed effects specifications to examine the distributional consequences of voluntary distributions. We find that districts with higher perpupil expenditures and higher enrollments are more likely to have one or more operating schoolsupporting charities, but that the level of per-pupil voluntary contributions declines with student enrollment. Higher-poverty school districts are less likely to be served by a school-supporting nonprofit and receive significantly lower voluntary contributions on a per-pupil basis. Finally, impressive recent growth in the number and financial size of these school supporting charities since 1995 has not offset reductions in state aid. Moreover, we do not find sufficient evidence to conclude that voluntary contributions change the distribution of funding across school districts and undo school finance equalization.LBJ School of Public Affair

Report of the Third Workshop on the Usage of NetFlow/IPFIX in Network Management

The Network Management Research Group (NMRG) organized in 2010 the Third Workshop on the Usage of NetFlow/IPFIX in Network Management, as part of the 78th IETF Meeting in Maastricht. Yearly organized since 2007, the workshop is an opportunity for people from both academia and industry to discuss the latest developments of the protocol, possibilities for new applications, and practical experiences. This report summarizes the presentations and the main conclusions of the workshop

Heating experiments of the Tagish Lake meteorite: Investigation of the effects of short-term heating on chondritic organics

We present in this study the effects of short-term heating on organics in the Tagish Lake meteorite and how the difference in the heating conditions can modify the organic matter (OM) in a way that complicates the interpretation of a parent body’s heating extent with common cosmothermometers. The kinetics of short-term heating and its influence on the organic structure are not well understood, and any study of OM is further complicated by the complex alteration processes of the thermally metamorphosed carbonaceous chondrites—potential analogues of the target asteroid Ryugu of the Hayabusa2 mission—which had experienced posthydration, short-duration local heating. In an attempt to understand the effects of short-term heating on chondritic OM, we investigated the change in the OM contents of the experimentally heated Tagish Lake meteorite samples using Raman spectroscopy, scanning transmission X-ray microscopy utilizing X-ray absorption near edge structure spectroscopy, and ultraperformance liquid chromatography fluorescence detection and quadrupole time of flight hybrid mass spectrometry. Our experiment suggests that graphitization of OM did not take place despite the samples being heated to 900 °C for 96 h, as the OM maturity trend was influenced by the heating conditions, kinetics, and the nature of the OM precursor, such as the presence of abundant oxygenated moieties. Although both the intensity of the 1s σ* exciton cannot be used to accurately interpret the peak metamorphic temperature of the experimentally heated Tagish Lake sample, the Raman graphite band widths of the heated products significantly differ from that of chondritic OM modified by long-term internal heating

Assessing unknown network traffic

Recent measurements have shown that a growing fraction of all Internet traffic is unknown: it is unclear which applications are causing the traffic. Therefore we have developed and applied a novel methodology to find out what applications are running on the network. This methodology is based on the notion of ¿induced traffic¿: traffic cannot (wide-scale) be on unknown ports, thus, \ud the hypothesis is that such traffic on unknown ports should be preceeded by traffic on known ports between the same peers. We have developed and implemented an algorithm to test this hypothesis. After applying the algorithm in two case studies we, unfortunately, have to conclude that although some improvement is made, there is still a significant fraction of traffic unidentifiable