Some resesarch on control of vibrations in civil engineering under covicocepad project

Some information is provided on the latest R&D within COVICOCEPAD project approved in the framework of Eurocores program. It addresses the use of TMD’s TLD’s, base isolation devices, MR dampers and a hybrid technique using both devices together. Some results are provided associated with calibration of a MR damper at FEUP, as well as its inclusion in a small scale laboratory set-up with proper equations of motion of the controlled smart structure. Applications of TMD’s devices to two civil engineering structures under dynamic and seismic actions are also outlined

Incremental cities : discovering the sweet spot for making town-within-a-city

This thesis studies how utterly marginalised people acquire acceptance or credibility - therefore participation - in the established civic and economic processes of a larger host municipality. In particular the signifi cance to this aspiration of incremental house and city-making is explored. The primary vehicle of interpretation is Savda Ghvera, a large resettlement colony for people resettled from central Delhi, for which the author organised a central sewerage system, which in turn became the basis for a neighbourhood association with political influence. Incrementalism describes a process of city-making in increments - as materials, time, etc. become available - mostly through the [self-] building of houses which, in their later stages, can support commercial or other activities. The main concern of this thesis is two-fold. Firstly it studies “shared incrementalism”, or the degree to which a commitment arises to a social and political context greater than an aggregate of individual houses. Secondly, it studies the role of making in creating the conditions for sharing, and with that, the roles of a visiting architect-researcher. On one hand, the constraints upon marginalised peoples are severe, and it is impossible to accurately assess the depth of commitment to both house and to a larger social and political order. On the other hand, it is evident that the opportunities for collaboration are volatile, constantly shifting, and that the virtues of solidarity are not necessarily accepted at face value. The process of shared incrementalism is seen through the lens of Amartya Sen’s concept of ‘freedom’ in the context of global capitalism, which places stress on what he terms ‘capacity-building’. The term emphasises the capacity of an individual to escape poverty and acquire dignity, whereas this thesis studies not only how this might be achieved through shared incrementalism but also the conditions under which this sharing might be converted into long-term political solidarity. Accordingly, comparison is made between Savda Ghevra and older resettlement colonies that have been absorbed by ever-expanding Delhi

A survey of statistical network models

Networks are ubiquitous in science and have become a focal point for discussion in everyday life. Formal statistical models for the analysis of network data have emerged as a major topic of interest in diverse areas of study, and most of these involve a form of graphical representation. Probability models on graphs date back to 1959. Along with empirical studies in social psychology and sociology from the 1960s, these early works generated an active network community and a substantial literature in the 1970s. This effort moved into the statistical literature in the late 1970s and 1980s, and the past decade has seen a burgeoning network literature in statistical physics and computer science. The growth of the World Wide Web and the emergence of online networking communities such as Facebook, MySpace, and LinkedIn, and a host of more specialized professional network communities has intensified interest in the study of networks and network data. Our goal in this review is to provide the reader with an entry point to this burgeoning literature. We begin with an overview of the historical development of statistical network modeling and then we introduce a number of examples that have been studied in the network literature. Our subsequent discussion focuses on a number of prominent static and dynamic network models and their interconnections. We emphasize formal model descriptions, and pay special attention to the interpretation of parameters and their estimation. We end with a description of some open problems and challenges for machine learning and statistics.Comment: 96 pages, 14 figures, 333 reference

UrbanDiary - a tracking project

This working paper investigates aspects of time in an urban environment, specifically the cycles and routines of everyday life in the city. As part of the UrbanDiary project (urbantick.blogspot.com), we explore a preliminary study to trace citizen’s spatial habits in individual movement utilising GPS devices with the aim of capturing the beat and rhythm of the city. The data collected includes time and location, to visualise individual activity, along with a series of personal statements on how individuals “use” and experience the city. In this paper, the intent is to explore the context of the UrbanDiary project as well as examine the methodology and technical aspects of tracking with a focus on the comparison of different visualisation techniques. We conclude with a visualisation of the collected data, specifically where the aspect of time is developed and explored so that we might outline a new approach to visualising the city in the sense of a collective, constantly renewed space

Analyzing helicopter evasive maneuver effectiveness against rocket-propelled grenades

It has long been acknowledged that military helicopters are vulnerable to ground-launched threats, in particular, the RPG-7 rocket-propelled grenade. Current helicopter threat mitigation strategies rely on a combination of operational tactics and selectively placed armor plating, which can help to mitigate but not entirely remove the threat. However, in recent years, a number of active protection systems designed to protect land-based vehicles from rocket and missile fire have been developed. These systems all use a sensor suite to detect, track, and predict the threat trajectory, which is then employed in the computation of an intercept trajectory for a defensive kill mechanism. Although a complete active protection system in its current form is unsuitable for helicopters, in this paper, it is assumed that the active protection system’s track and threat trajectory prediction subsystem could be used offline as a tool to develop tactics and techniques to counter the threat from rocket-propelled grenade attacks. It is further proposed that such a maneuver can be found by solving a pursuit–evasion differential game. Because the first stage in solving this problem is developing the capability to evaluate the game, nonlinear dynamic and spatial models for a helicopter, RPG-7 round, and gunner, and evasion strategies were developed and integrated into a new simulation engine. Analysis of the results from representative vignettes demonstrates that the simulation yields the value of the engagement pursuit–evasion game. It is also shown that, in the majority of cases, survivability can be significantly improved by performing an appropriate evasive maneuver. Consequently, this simulation may be used as an important tool for both designing and evaluating evasive tactics and is the first step in designing a maneuver-based active protection system, leading to improved rotorcraft survivability

R&D on control of vibrations under covicocepad during 2007-2008

This paper provides information on the latest R&D within COVICOCEPAD project approved in the framework of Eurocores program. It addresses the use of TLD, base isolation devices, MR dampers and a hybrid technique using both devices together. Some results are provided associated with calibration of a MR damper at FEUP, as well as its inclusion in a small scale laboratory set-up with proper equations of motion of the controlled smart structure. An application of semi-active control technique to a bridge is outlined. Further remarks and details on future tests to be performed in LNEC shaking table, within COVICOCEPAD project, are provided