Integración del módulo DeviceView que permite gestionar switches multi-vendor al sistema de monitoreo de red Open Source Nagios, para centralizar la administración en redes LAN

Se expone una síntesis de la construcción de un prototipo de software denominado DeviceView que permite a los administradores de red gestionar de forma gráfica dispositivos activos de red (de tipo switch) que se encuentren en su red LAN (red de área local) (Limoncelli, Hogan y Chalup, 2007). De esta forma, el dministrador de red no tiene que dirigirse a cada una de las aplicaciones de gestión creadas por cada fabricante de dispositivos activos en particular, debido a que estas herramientas no permiten administrar dispositivos activos de otros fabricantes que por lo general existen en la misma red (dato del porcentaje de redes LAN que cuentan con dispositivos activos de red de más de un fabricante). Para facilitar y centralizar la tarea al administrador de red, el DeviceView está integrado al Sistema de Monitoreo de Redes de código abierto Nagios (Silver; Harlan, 2003); este no requiere licenciamiento adicional para su operación, lo que facilita su uso y proporciona al administrador de red una única interfaz (Web) para realizar sus tareas de monitoreo de equipos y servicios, gestión de red y de sus dispositivos activos

Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 5: Unsteady counterrotation ducted propfan analysis. Computer program user's manual

The primary objective of this study was the development of a time-marching three-dimensional Euler/Navier-Stokes aerodynamic analysis to predict steady and unsteady compressible transonic flows about ducted and unducted propfan propulsion systems employing multiple blade rows. The computer codes resulting from this study are referred to as ADPAC-AOACR (Advanced Ducted Propfan Analysis Codes-Angle of Attack Coupled Row). This report is intended to serve as a computer program user's manual for the ADPAC-AOACR codes developed under Task 5 of NASA Contract NAS3-25270, Unsteady Counterrotating Ducted Propfan Analysis. The ADPAC-AOACR program is based on a flexible multiple blocked grid discretization scheme permitting coupled 2-D/3-D mesh block solutions with application to a wide variety of geometries. For convenience, several standard mesh block structures are described for turbomachinery applications. Aerodynamic calculations are based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. Steady flow predictions are accelerated by a multigrid procedure. Numerical calculations are compared with experimental data for several test cases to demonstrate the utility of this approach for predicting the aerodynamics of modern turbomachinery configurations employing multiple blade rows

Managing the bazaar: commercialization and peripheral participation in mature, community-led free/open source software projects

The thesis investigates two fundamental dynamics of participation and collaboration in mature, community-led Free/Open Source (F/OS) software projects - commercialization and peripheral participation. The aim of the thesis is to examine whether the power relations that underlie the F/OS model of development are indicative of a new form of power relations supported by ICTs. Theoretically, the thesis is located within the Communities of Practice (CoP) literature and it draws upon Michel Foucault's ideas about the historical and relational character of power. It also mobilizes, to a lesser extent, Erving Goffman's notion of `face-work'. This framework supports a methodology that questions the rationality of how F/OS is organized and examines the relations between employed coders and volunteers, experienced and inexperienced coders, and programmers and nonprogrammers. The thesis examines discursive and structural dimensions of collaboration and employs quantitative and qualitative methods. Structural characteristics are considered in the light of arguments about embeddedness. The thesis contributes insights into how the gift economy is embedded in the exchange economy and the role of peripheral contributors. The analysis indicates that community-integrated paid developers have a key role in project development, maintaining the infrastructure aspects of the code base. The analysis suggests that programming and non-programming contributors are distinct in their make-up, priorities and rhythms of participation, and that learning plays an important role in controlling access. The results show that volunteers are important drivers of peripheral activities, such as translation and documentation. The term `autonomous peripherality' is used to capture the unique characteristics of these activities. These findings support the argument that centrality and peripherality are associated with the division of labour, which, in turn, is associated with employment relations and frameworks of institutional support. The thesis shows how the tensions produced by commercialization and peripheral participation are interwoven with values of meritocracy, ritual and strategic enactment of the idea of community as well as with tools and techniques developed to address the emergence of a set of problems specific to management and governance. These are characterized as `technologies of communities'. It is argued that the emerging topology of F/OS participation, seen as a `relational meshwork', is indicative of a redefinition of the relationship between sociality and economic production within mature, community-led F/OS projects

A Functional Approach to Memory-Safe Operating Systems

Purely functional languages--with static type systems and dynamic memory management using garbage collection--are a known tool for helping programmers to reduce the number of memory errors in programs. By using such languages, we can establish correctness properties relating to memory-safety through our choice of implementation language alone. Unfortunately, the language characteristics that make purely functional languages safe also make them more difficult to apply in a low-level domain like operating systems construction. The low-level features that support the kinds of hardware manipulations required by operating systems are not typically available in memory-safe languages with garbage collection. Those that are provided may have the ability to violate memory- and type-safety, destroying the guarantees that motivate using such languages in the first place. This work demonstrates that it is possible to bridge the gap between the requirements of operating system implementations and the features of purely functional languages without sacrificing type- and memory-safety. In particular, we show that this can be achieved by isolating the potentially unsafe memory operations required by operating systems in an abstraction layer that is well integrated with a purely functional language. The salient features of this abstraction layer are that the operations it exposes are memory-safe and yet sufficiently expressive to support the implementation of realistic operating systems. The abstraction layer enables systems programmers to perform all of the low-level tasks necessary in an OS implementation, such as manipulating an MMU and executing user-level programs, without compromising the static memory-safety guarantees of programming in a purely functional language. A specific contribution of this work is an analysis of memory-safety for the abstraction layer by formalizing a meaning for memory-safety in the presence of virtual-memory using a novel application of noninterference security policies. In addition, we evaluate the expressiveness of the abstraction layer by implementing the L4 microkernel API, which has a flexible set of virtual memory management operations

Investigation of Advanced Counterrotation Blade Configuration Concepts for High Speed Turboprop Systems. Task 8: Cooling Flow/heat Transfer Analysis User's Manual

The focus of this task was to validate the ADPAC code for heat transfer calculations. To accomplish this goal, the ADPAC code was modified to allow for a Cartesian coordinate system capability and to add boundary conditions to handle spanwise periodicity and transpiration boundaries. This user's manual describes how to use the ADPAC code as developed in Task 5, NAS3-25270, including the modifications made to date in Tasks 7 and 8, NAS3-25270

Network knowledge and route choice

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.Includes bibliographical references (p. 225-236).Models of urban traveler route choice are reviewed in the context of Intelligent Transportation Systems, particularly Advanced Traveler Information S ystems. Existing models suffer from assumptions of perfect information about travel conditions a nd infinite information processing capabilities of drivers. We present evidence that a majority of travelers fail to minimize travel time or distance. We also show that travelers with more network knowledge appear to vary their commute route to respond to changing travel conditions. Coefficient estimates of a model of network knowledge, based on the geographical idea of spatial ability, are presented. To better understand habitual route choice behavior, we examine many possible route generation algorithms. A simulation approach is preferred because it allows for heterogeneity in driver perceptions and it has a quick computational time. Alternative route choice model specifications such as Multinomial Logit, C-Logit, Path Size Logit, Cross-Nested Logit and Logit Kernel Probit are evaluated. The exponential specification of the Path S ize term, using a large parameter value, offers a considerable improvement in fit over MNL, C -Logit and CNL. A hybrid Path Size Logit and Logit Kernel Probit model offers the best overall fit; however, the stability of these estimates requires further examination. The hybrid Path S ize Logit and CNL model provides the next best empirical fit. Random coefficient specifications of MNL, PS L and LK Probit models were also examined.Significant random coefficient parameter estimates were only obtained for the MNL model. This result suggests that random coefficients capture variation in route choice models that would be more effectively explained by a Path S ize or LK Probit specification. Model fit can be further improved by adding an Implicit Availability/Perception term that includes estimated network knowledge. However, this term provides limited explanatory power, as can be seen by its standard errors and by forecasts that are relatively insensitive to changes in traveler knowledge. These results suggest that continued development of better attitudinal surveys to assess network knowledge and wayfinding strategies would allow estimation of route choice models with better explanatory power.by Michael Scott Ramming.Ph.D

The nature of management work.

The thesis contributes to an understanding of the nature of Managerial work, confronting the work in its natural setting. It offers an empirically grounded description of the social organisation of managerial work; it explores the taken for granted features of managers'work that allows members to recognise and reproduce their normal everyday activities amid the variability and complexity that comprises their days work. The study finds managerial work to be a primarily verbal activity; accessible through a study of interaction. Resources of Conversation Analysis are utilised to explore how the managers use talk to accomplish their activities and to expose and test their understanding. An ethnographically informed approach reveals that the social organisation of the work is inextricable from local, referential matters. The thesis is presented in two parts. Part I explorest he 'insitu' accomplishment of a number of activities within selected instances of managerial work; a memo,a discussion of future work plans and a strategic planning meeting. It finds and demonstrates how such work as negotiating a position, identifying a problem reaching agreement is not just the outcome of a sequential organisation but of a retrospective-prospective design. Phenomena such as 'planning' and 'organising' are appropriated at the interactional level. They are found to be achieved in the insitu accomplishment of various conversational features; agreement and modification amongst others, through an understanding of local contingencies such as time scales for projects, the personalities involved, and by practices of description and explanation. Part 2 takes up an interest, begun in Part 1, with occasions when the managers offer explanations of their work. The ability to "talk about management" is found to be a competenc essential to the accomplishment of a number of managerial activities such as working up plans, making sensible a proposal. A number of occasions where particular managers offer verbal 'tours' of their work are explored. Not only doest his reveal something of how accounts get done, but it brings into the public domain some of the 'commonsense understandings' that the managers orientate in shaping up a telling of their work. Attention to these 'espoused logics' 'lines of regard' is important in terms of developing an adequate theory of the organisation of managerial work. It could be on the basis of these' practical theories' that the managers work proceeds that particular decisions get taken, plans are agreed etc

Public Expenditure Planning in New Zealand

It is argued in this thesis that over the past 15 years planning - and in particular expenditure planning - has had three main functions in New Zealand central government: as a survival mechanism for elites; as a means to cope with the problems and deficiencies of organised knowledge; and as a symbolic act of reassurance in the face of economic and fiscal uncertainty. Expenditure planning is regarded in this work as a learning process. However, the thesis describes historical developments which illustrate that the imperative need to contain and manage conflict inside central government is such that real executive learning is effectively precluded. Dissonance between the political implications of significant information and the rational action that might be dictated by that information inhibits effective communication and control. The cybernetic malfunctioning of the central system arises not so much from political debate over the fiscal issues as from the need of certain elites to retain their pre-eminence in the planning process - most notably, the Treasury and its associated ministers. It is concluded that a less historically-bound system of power-sharing is called for if the executive agents - officials and ministers - are to react more sensitively to adverse fiscal circumstances and prepare more efficiently for future uncertainties than they have in the past

Bowdoin Orient v.96, no.1-24 (1966-1967)

https://digitalcommons.bowdoin.edu/bowdoinorient-1960s/1007/thumbnail.jp