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

Low-Temperature Migration of Silicon in Metal Films on Silicon Substrates Studied by Backscattering Techniques

The backscattering method using 2-MeV^(4)He^(+) ions is employed to obtain microscopic information about solid-solid reaction of Si with thin layers (200∼4000 Å) of Au, Ag, and Al which are vacuum evaporated onto Si crystal substrates. The interesting observation is the migration of Si atoms into these metal films at temperatures (for example, 150°C in Au, 400°C in Ag) well below their eutectic points (375°C for Au and 850°C for Ag). This phenomenon also indicates that at these low temperatures the dislodgment of Si atoms from tightly bound Si crystal does occur. Our experiments clarify that the origin of this effect is the interaction of Si with metals at the interface

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

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

On gradual-impulse control of continuous-time Markov decision processes with multiplicative cost

In this paper, we consider the gradual-impulse control problem of continuous-time Markov decision processes, where the system performance is measured by the expectation of the exponential utility of the total cost. We prove, under very general conditions on the system primitives, the existence of a deterministic stationary optimal policy out of a more general class of policies. Policies that we consider allow multiple simultaneous impulses, randomized selection of impulses with random effects, relaxed gradual controls, and accumulation of jumps. After characterizing the value function using the optimality equation, we reduce the continuous-time gradual-impulse control problem to an equivalent simple discrete-time Markov decision process, whose action space is the union of the sets of gradual and impulsive actions

Smart Dimensioning of IP Network Links

Link dimensioning is generally considered as an effective and (operationally) simple mechanism to meet (given) performance requirements. In practice, the required link capacity C is often estimated by rules of thumb, such as C = d·M, where M is the (envisaged) average traffic rate, and d some (empirically determined) constant larger than 1. This paper studies the viability of this class of ‘simplistic’ dimensioning rules. Throughout, the performance criterion imposed is that the fraction of intervals of length T in which the input exceeds the vailable output capacity (i.e., CT) should not exceed $\varepsilon$, for given T and $\varepsilon$.\ud We first present a dimensioning formula that expresses the required link capacity as a function of M and a variance term V(T), which captures the burstiness on timescale T. We explain how M and V(T) can be estimated with low measurement effort. The dimensioning formula is then used to validate dimensioning rules of the type C = d·M. Our main findings are: (i) the factor d is strongly affected by the nature of the traffic, the level of aggregation, and the network infrastructure; if these conditions are more or less constant, one could empirically determine d; (ii) we can explicitly characterize how d is affected by the ‘performance parameters’, i.e., T and $\varepsilon$

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

Analysing representations of the comfort women issue : gender, race, nation and subjectivities

Employs post-structuralist theories of subjectivity as well as feminism and men's studies (particularly as it exists in America) to explore the experience, gender subjectivites and national and racial subjectivities in personal narratives of ex-comfort women and ex-Japanese soldiers.Thesis (M.A.) -- University of Adelaide, Dept. of Social Inquiry, 199