Governance and post-statist security: The politics of US and Norwegian foreign aid for demining in Afghanistan, Bosnia and Sudan.

While governance has traditionally been the realm of states, new "Emerging Political Complexes," as Mark Duffield calls them, incorporate networks of public and private actors. These networks of governance come in two competing ideal types: a) strategic-commercial complexes, shaped by particularist interests, that provide protection to a select few, whether citizens of a great power or 'the client', and b) human security-civil society complexes, shaped by norms, ideals and more global notions of public interest, that aim to extend protection to whole populations. This PhD examines the effects and impact of these two approaches in managing and neutralizing the threat of landmines and unexploded ordnance. At the donor level, it compares the US and Norway, arguing that Norway, working with NGOs, churches and other small states, has been at the forefront of efforts to ban landmines and cluster munitions, whereas the US has resisted tight regulation. Moreover, US funding of clearance and mitigation programs was shaped by narrow strategic interests and favored a commercially-driven process. In contrast, Norway's programs, implemented through international NGOs, were shaped more by more global conceptions of interest and normative commitments to humanitarianism, multilateralism and international law. At the level of implementation in mine and ordnance-affected countries - Afghanistan, Bosnia and Sudan - the PhD argues that Norwegian long-term grants to international NGOs produced demining that, while more expensive and slower, was better targeted on humanitarian priorities, safer and of better quality. Such programs also attempted to build inclusive institutions and resist the politics of violence. In contrast, US efforts, often driven by strategic concems and tendered out to commercial companies, were cheaper and faster but also less safe and of lower quality. These companies were also embedded in the political economy of war and may have contributed to the fragmentation of the public monopoly on force

Performance Bounds for Synchronized Queueing Networks

Las redes de Petri estocásticas constituyen un modelo unificado de las diferentes extensiones de redes de colas con sincronizaciones existentes en la literatura, válido para el diseño y análisis de prestaciones de sistemas informáticos distribuidos. En este trabajo se proponen técnicas de cálculo de cotas superiores e inferiores de las prestaciones de redes de Petri estocásticas en estado estacionario. Las cotas obtenidas son calculables en tiempo polinómico en el tamaño del modelo, por medio de la resolución de ciertos problemas de programación lineal definidos a partir de la matriz de incidencia de la red (en este sentido, las técnicas desarrolladas pueden considerarse estructurales). Las cotas calculadas dependen sólamente de los valores medios de las variables aleatorias que describen la temporización del sistema, y son independientes de los momentos de mayor orden. Esta independencia de la forma de las distribuciones de probabilidad asociadas puede considerarse como una útil generalización de otros resultados existentes para distribuciones particulares, puesto que los momentos de orden superior son, habitualmente, desconocidos en la realidad y difíciles de estimar. Finalmente, las técnicas desarrolladas se aplican al análisis de diferentes ejemplos tomados de la literatura sobre sistemas informáticos distribuidos y sistemas de fabricación. ******* Product form queueing networks have long been used for the performance evaluation of computer systems. Their success has been due to their capability of naturally expressing sharing of resources and queueing, that are typical situations of traditional computer systems, as well as to their efficient solution algorithms, of polynomial complexity on the size of the model. Unfortunately, the introduction of synchronization constraints usually destroys the product form solution, so that general concurrent and distributed systems are not easily studied with this class of models. Petri nets have been proved specially adequate to model parallel and distributed systems. Moreover, they have a well-founded theory of analysis that allows to investigate a great number of qualitative properties of the system. In the original definition, Petri nets did not include the notion of time, and tried to model only the logical behaviour of systems by describing the causal relations existing among events. This approach showed its power in the specification and analysis of concurrent systems in a way independent of the concept of time. Nevertheless the introduction of a timing specification is essential if we want to use this class of models for the performance evaluation of distributed systems. One of the main problems in the actual use of timed and stochastic Petri net models for the quantitative evaluation of large systems is the explosion of the computational complexity of the analysis algorithms. In general, exact performance results are obtained from the numerical solution of a continuous time Markov chain, whose dimension is given by the size of the state space of the model. Structural computation of exact performance measures has been possible for some subclasses of nets such as those with state machine topology. These nets, under certain assumptions on the stochastic interpretation are isomorphic to Gordon and Newell's networks, in queueing theory terminology. In the general case, efficient methods for the derivation of performance measures are still needed. Two complementary approaches to the derivation of exact measures for the analysis of distributed systems are the utilization of approximation techniques and the computation of bounds. Approximate values for the performance parameters are in general more efficiently derived than the exact ones. On the other hand, "exactness" only exists in theory! In other words, numerical algorithms must be applied in practice for the computation of exact values, therefore making errors is inevitable. Performance bounds are useful in the preliminary phases of the design of a system, in which many parameters are not known accurately. Several alternatives for those parameters should be quickly evaluated, and rejected those that are clearly bad. Exact (and even approximate) solutions would be computationally very expensive. Bounds become useful in these instances since they usually require much less computation effort. The computation of upper and lower bounds for the steady-state performance of timed and stochastic Petri nets is considered in this work. In particular, we study the throughput of transitions, defined as the average number of firings per time unit. For this measure we try to compute upper and lower bounds in polynomial time on the size of the net model, by means of proper linear programming problems defined from the incidence matrix of the net (in this sense, we develop structural techniques). These bounds depend only on the mean values and not on the higher moments of the probability distribution functions of the random variables that describe the timing of the system. The independence of the probability distributions can be viewed as a useful generalization of the performance results, since higher moments of the delays are usually unknown for real cases, and difficult to estimate and assess. From a different perspective, the obtained results can be applied to the analysis of queueing networks extended with some synchronization schemes. Monoclass queueing networks can be mapped on stochastic Petri nets. On the other hand, stochastic Petri nets can be interpreted as monoclass queueing networks augmented with synchronization primitives. Concerning the presentation of this manuscript, it should be mentioned that chapter 1 has been written with the object of giving the reader an outline of the stochastic Petri net model: its definition, terminology, basic properties, and related concepts, together with its deep relation with other classic stochastic network models. Chapter 2 is devoted to the presentation of the net subclasses considered in the rest of the work. The classification presented here is quite different from the one which is usual in the framework of Petri nets. The reason lies on the fact that our classification criterion, the computability of visit ratios for transitions, is introduced for the first time in the field of stochastic Petri nets in this work. The significance of that criterion is based on the important role that the visit ratios play in the computation of upper and lower bounds for the performance of the models. Nevertheless, classical important net subclasses are identified here in terms of the computability of their visit ratios from different parameters of the model. Chapter 3 is concerned with the computation of reachable upper and lower bounds for the most restrictive subclass of those presented in chapter 2: marked graphs. The explanation of this fact is easy to understand. The more simple is the model the more accessible will be the techniques an ideas for the development of good results. Chapter 4 provides a generalization for live and bounded free choice nets of the results presented in the previous chapter. Quality of obtained bounds is similar to that for strongly connected marked graphs: throughput lower bounds are reachable for bounded nets while upper bounds are reachable for 1-bounded nets. Chapter 5 considers the extension to other net subclasses, like mono-T-semiflow nets, FRT-nets, totally open deterministic systems of sequential processes, and persistent nets. The results are of diverse colours. For mono-T-semiflow nets and, therefore, for general FRT-nets, it is not possible (so far) to obtain reachable throughput bounds. On the other hand, for bounded ordinary persistent nets, tight throughput upper bounds are derived. Moreover, in the case of totally open deterministic systems of sequential processes the exact steady-state performance measures can be computed in polynomial time on the net size. In chapter 6 bounds for other interesting performance measures are derived from throughput bounds and from classical queueing theory laws. After that, we explore the introduction of more information from the probability distribution functions of service times in order to improve the bounds. In particular, for Coxian service delay of transitions it is possible to improve the throughput upper bounds of previous chapters which held for more general forms of distribution functions. This improvement shows to be specially fruitful for live and bounded free choice nets. Chapter 7 is devoted to case studies. Several examples taken from literature in the fields of distributed computing systems and manufacturing systems are modelled by means of stochastic Petri nets and evaluated using the techniques developed in previous chapters. Finally, some concluding remarks and considerations on possible extensions of the work are presented

Data bases and data base systems related to NASA's Aerospace Program: A bibliography with indexes

This bibliography lists 641 reports, articles, and other documents introduced into the NASA scientific and technical information system during the period January 1, 1981 through June 30, 1982. The directory was compiled to assist in the location of numerical and factual data bases and data base handling and management systems

Left and Right: Politics and Images of Motherhood in Weimar Germany

Art historians and cultural critics have long debated the aesthetic and political implications of the stylistic shift in Germany from pre-war experimentations with abstraction and expressive distortion to more clear-cut figuration in their paintings during the years following World War I. They have questioned whether this shift represents a regressive return to tradition or a new artistic direction and if it should be associated with a reactionary or progressive political stance. This dissertation broadens our understanding of German interwar realism, commonly referred to as Neue Sachlichkeit, by examining representations of mothers, a popular theme in the realist painting of the Weimar period (1919-1933). Through a series of case studies I explore how artists, as well as art critics and collectors, working from a range of political positions, used the image of the mother, employing various strategies of realism, to engage with the social and political conflicts of the tumultuous Weimar years. Focusing first on leftist figures I examine how socially-engaged artists, including Käthe Kollwitz and Rudolf Schlichter, produced simplistically realistic images of proletarian mothers as propaganda for the German Communist Party’s campaign to legalize abortion. I then study the veristic realism of representations of working-class mothers by Otto Dix, one of the most (in)famous painters of the Weimar period, in an attempt to resolve the controversy about whether his minute attention to detail and exaggerated color typical of the German Old Masters relates to a need to expose the social evils of the Weimar years. The next chapter focuses on Georg Schrimpf’s maternal images and how his employment of an idealizing and classicizing naturalism grounded in the Italianate pastoral tradition gives form to his utopian, anarcho-socialist beliefs. In the final chapter I consider how members of the Weimar art world affiliated with the political right also championed artistic realism by examining the posthumous reception of Paula-Modersohn Becker. As I discuss, numerous right-wing art historians, critics and collectors appropriated her motherhood works to support various nationalist and conservative agendas. By demonstrating the political and stylistic complexity of German interwar painting, my dissertation challenges previous attempts to interpret Neue Sachlichkeit simplistically as either right/reactionary or left/liberal while also opening up new understandings of some of the movement’s most important members

Spacelab Science Results Study

Beginning with OSTA-1 in November 1981 and ending with Neurolab in March 1998, a total of 36 Shuttle missions carried various Spacelab components such as the Spacelab module, pallet, instrument pointing system, or mission peculiar experiment support structure. The experiments carried out during these flights included astrophysics, solar physics, plasma physics, atmospheric science, Earth observations, and a wide range of microgravity experiments in life sciences, biotechnology, materials science, and fluid physics which includes combustion and critical point phenomena. In all, some 764 experiments were conducted by investigators from the U.S., Europe, and Japan. The purpose of this Spacelab Science Results Study is to document the contributions made in each of the major research areas by giving a brief synopsis of the more significant experiments and an extensive list of the publications that were produced. We have also endeavored to show how these results impacted the existing body of knowledge, where they have spawned new fields, and if appropriate, where the knowledge they produced has been applied