Control of bimanual rhythmic movements: Trading efficiency for robustness depending on the context

This paper investigates how the efficiency and robustness of a skilled rhythmic task compete against each other in the control of a bimanual movement. Human subjects juggled a puck in 2D through impacts with two metallic arms, requiring rhythmic bimanual actuation. The arms kinematics were only constrained by the position, velocity and time of impacts while the rest of the trajectory did not influence the movement of the puck. In order to expose the task robustness, we manipulated the task context in two distinct manners: the task tempo was assigned at four different values (hence manipulating the time available to plan and execute each impact movement individually); and vision was withdrawn during half of the trials (hence reducing the sensory inflows). We show that when the tempo was fast, the actuation was rhythmic (no pause in the trajectory) while at slow tempo, the actuation was discrete (with pause intervals between individual movements). Moreover, the withdrawal of visual information encouraged the rhythmic behavior at the four tested tempi. The discrete versus rhythmic behavior give different answers to the efficiency/robustness trade-off: discrete movements result in energy efficient movements, while rhythmic movements impact the puck with negative acceleration, a property preserving robustness. Moreover, we report that in all conditions the impact velocity of the arms was negatively correlated with the energy of the puck. This correlation tended to stabilize the task and was influenced by vision, revealing again different control strategies. In conclusion, this task involves different modes of control that balance efficiency and robustness, depending on the context. © 2008 Springer-Verlag.

The origins of the control of information in war coverage

The conflict’s coverage, since its inception, has been closely linked to the relationship that both the military and the media have. The freedom they maintained during their first conflicts, although not without problems, though they suffered strict censorship suffered during World War I, and lastly the straitjacket treatment that they have endured during recent wars. The Vietnam War marked a turning point in this relationship, and after the invasion of Grenada, the military would launch new information guidelines, called Department of Defense National Media Pool. The lack of clear guidance of both control and space, has made for a complicated relationship between media and military, so the rules have evolved after every conflict shaping the future of press coverage and thus, war reporting.

A Capabilities-Aware Framework for Using Computational Accelerators in Data-Intensive Computing

Multicore computational accelerators such as GPUs are now commodity components for highperformance computing at scale. While such accelerators have been studied in some detail as stand-alone computational engines, their integration in large-scale distributed systems raises new challenges and trade-offs. In this paper, we present an exploration of resource management alternatives for building asymmetric accelerator-based distributed systems. We present these alternatives in the context of a capabilities-aware framework for data-intensive computing, which uses an enhanced implementation of the MapReduce programming model for accelerator-based clusters, compared to the state of the art. The framework can transparently utilize heterogeneous accelerators for deriving high performance with low programming effort. Our work is the first to compare heterogeneous types of accelerators, GPUs and a Cell processors, in the same environment and the first to explore the trade-offs between compute-efficient and control-efficient accelerators on data-intensive systems. Our investigation shows that our framework scales well with the number of different compute nodes. Furthermore, it runs simultaneously on two different types of accelerators, successfully adapts to the resource capabilities, and performs 26.9% better on average than a static execution approach.

Making geography mobile: using location aware technology to improve student performance in physical geography

With the increased availability of new technologies, geography educators are revisiting their pedagogical approaches to teaching and calling for opportunities to share local and international practices which will enhance the learning experience and improve students’ performance. This paper reports on the use of handheld mobile devices, fitted with GPS, by secondary (high) school pupils in geography. Two location-aware activities were completed over one academic year (one per semester) and pre-test and post-test scores for both topics revealed a statistically significant increase in pupils’ performance as measured by the standard national assessments. A learner centred educational approach was adopted with the first mobile learning activity being created by the teacher as an exemplar of effective mobile learning design. Pupils built on their experiences of using mobile learning when they were required to created their own location aware learning task for peer use. An analysis of the qualitative data from the pupils’ journals, group diaries and focus group interviews revealed the five pillars of learner centred education are addressed when using location aware technologies and the use of handheld mobile devices offered greater flexibility and autonomy to the pupils thus altering the level of power and control away from the teacher. Due to the relatively small number of participants in the study, the results are more informative than generalisable however in light of the growing interest in geo-spatial technologies in geography education, this paper offers encouragement and insight into the use of location aware technology in a compulsory school context

Contested urbanism: Access and control issues in Tundikhel, Kathmandu

Contested Open Spaces?: Access and control issues in Tundikhel, Kathmandu

Public spaces play a role of political, economic and cultural transformation of cities and the impact of these transformations on the nature of public space.

Urban open space(s) in Kathmandu have been an important part of the city’s urbanism. Historically they have played an important role in the city as spaces for religious, cultural, social and political and military activities during the 300 years of unified monarchy. Throughout the civil war period (Maoist insurgency between 1996 and 2006) they became material locations for political activities, and a site for protests and dharnas. In post-conflict Kathmandu, especially since the abolition of Monarchy in May 28, 2008, these spaces are increasingly seen being claimed by street hawkers, informal sellers and individuals reflecting a new set of users and functions, whereas a significant part of Tundikhel still remains under the military occupation posing important questions around access, identity and control of an important space.


Public spaces are broadly defined as crossroads where different paths and trajectories meet, sometimes overlapping and other times colliding (Madanipour, 2003). Using Tudikhel in Kathmandu, this research examines the increasing collision and contestations witnessed through social, political and neoliberal interactions. It explores how spaces are constantly
contested, negotiated and as a result reshaped through these interactions. It is observed that multiple forces are at play to gain control and access of this important open space, leading to increasing fragmentation of the space, and erosion of its historic significance both as cultural venue and a symbol of democracy in modern Nepal. It is argued that increasing disconnection of Tudikhel from wider urban setting has contributed to exacerbation of these contestations

Control design for multicast-aware class-based networks

The expectations of citizens from the Information Technologies (ITs) are increasing as the ITs have become integral part of our society, serving all kinds of activities whether professional, leisure, safety-critical applications or business. Hence, the limitations of the traditional network designs to provide innovative and enhanced services and applications motivated a consensus to integrate all services over packet switching infrastructures, using the Internet Protocol, so as to leverage flexible control and economical benefits in the Next Generation Networks (NGNs). However, the Internet is not capable of treating services differently while each service has its own requirements (e.g., Quality of Service - QoS). Therefore, the need for more evolved forms of communications has driven to radical changes of architectural and layering designs which demand appropriate solutions for service admission and network resources control. This Thesis addresses QoS and network control issues, aiming to improve overall control performance in current and future networks which classify services into classes. The Thesis is divided into three parts. In the first part, we propose two resource over-reservation algorithms, a Class-based bandwidth Over-Reservation (COR) and an Enhanced COR (ECOR). The over-reservation means reserving more bandwidth than a Class of Service (CoS) needs, so the QoS reservation signalling rate is reduced. COR and ECOR allow for dynamically defining over-reservation parameters for CoSs based on network interfaces resource conditions; they aim to reduce QoS signalling and related overhead without incurring CoS starvation or waste of bandwidth. ECOR differs from COR by allowing for optimizing control overhead minimization. Further, we propose a centralized control mechanism called Advanced Centralization Architecture (ACA), that uses a single state-full Control Decision Point (CDP) which maintains a good view of its underlying network topology and the related links resource statistics on real-time basis to control the overall network. It is very important to mention that, in this Thesis, we use multicast trees as the basis for session transport, not only for group communication purposes, but mainly to pin packets of a session mapped to a tree to follow the desired tree. Our simulation results prove a drastic reduction of QoS control signalling and the related overhead without QoS violation or waste of resources. Besides, we provide a generic-purpose analytical model to assess the impact of various parameters (e.g., link capacity, session dynamics, etc.) that generally challenge resource overprovisioning control. In the second part of this Thesis, we propose a decentralization control mechanism called Advanced Class-based resource OverpRovisioning (ACOR), that aims to achieve better scalability than the ACA approach. ACOR enables multiple CDPs, distributed at network edge, to cooperate and exchange appropriate control data (e.g., trees and bandwidth usage information) such that each CDP is able to maintain a good knowledge of the network topology and the related links resource statistics on real-time basis. From scalability perspective, ACOR cooperation is selective, meaning that control information is exchanged dynamically among only the CDPs which are concerned (correlated). Moreover, the synchronization is carried out through our proposed concept of Virtual Over-Provisioned Resource (VOPR), which is a share of over-reservations of each interface to each tree that uses the interface. Thus, each CDP can process several session requests over a tree without requiring synchronization between the correlated CDPs as long as the VOPR of the tree is not exhausted. Analytical and simulation results demonstrate that aggregate over-reservation control in decentralized scenarios keep low signalling without QoS violations or waste of resources. We also introduced a control signalling protocol called ACOR Protocol (ACOR-P) to support the centralization and decentralization designs in this Thesis. Further, we propose an Extended ACOR (E-ACOR) which aggregates the VOPR of all trees that originate at the same CDP, and more session requests can be processed without synchronization when compared with ACOR. In addition, E-ACOR introduces a mechanism to efficiently track network congestion information to prevent unnecessary synchronization during congestion time when VOPRs would exhaust upon every session request. The performance evaluation through analytical and simulation results proves the superiority of E-ACOR in minimizing overall control signalling overhead while keeping all advantages of ACOR, that is, without incurring QoS violations or waste of resources. The last part of this Thesis includes the Survivable ACOR (SACOR) proposal to support stable operations of the QoS and network control mechanisms in case of failures and recoveries (e.g., of links and nodes). The performance results show flexible survivability characterized by fast convergence time and differentiation of traffic re-routing under efficient resource utilization i.e. without wasting bandwidth. In summary, the QoS and architectural control mechanisms proposed in this Thesis provide efficient and scalable support for network control key sub-systems (e.g., QoS and resource control, traffic engineering, multicasting, etc.), and thus allow for optimizing network overall control performance.

Scalable semantic aware context storage

In recent years the Internet has grown by incorporating billions of small devices, collecting real-world information and distributing it though various systems. As the number of such devices grows, it becomes increasingly difficult to manage all these new information sources. Several context representation schemes have tried to standardize this information, however none of them have been widely adopted. Instead of proposing yet another context representation scheme, we discuss an efficient way to deal with this diversity of representation schemes. We define the basic requirements for context storage systems, analyse context organizations models and propose a new context storage solution. Our solution implements an organizational model that improves scalability, semantic extraction and minimizes semantic ambiguity.

PREGNANCY-RELATED CHURN AND ACCESS TO CARE IN THE CONTEXT OF NARROW NETWORKS IN WASHINGTON STATE

Thesis (Master's)--University of Washington, 2016-03

Intelligent energy resources management in the context of smart grids

Smart grids are envisaged as infrastructures able to accommodate all centralized and distributed energy resources (DER), including intensive use of renewable and distributed generation (DG), storage, demand response (DR), and also electric vehicles (EV), from which plug-in vehicles, i.e. gridable vehicles, are especially relevant. Moreover, smart grids must accommodate a large number of diverse types or players in the context of a competitive business environment. Smart grids should also provide the required means to efficiently manage all these resources what is especially important in order to make the better possible use of renewable based power generation, namely to minimize wind curtailment. An integrated approach, considering all the available energy resources, including demand response and storage, is crucial to attain these goals. This paper proposes a methodology for energy resource management that considers several Virtual Power Players (VPPs) managing a network with high penetration of distributed generation, demand response, storage units and network reconfiguration. The resources are controlled through a flexible SCADA (Supervisory Control And Data Acquisition) system that can be accessed by the evolved entities (VPPs) under contracted use conditions. A case study evidences the advantages of the proposed methodology to support a Virtual Power Player (VPP) managing the energy resources that it can access in an incident situation.

Scalable and interference aware wi-fi mesh networks using cots devices

A crescente tendencia no acesso móvel tem sido potenciada pela tecnologia IEEE 802.11. Contudo, estas redes têm alcance rádio limitado. Para a extensão da sua cobertura é possível recorrer a redes emalhadas sem fios baseadas na tecnologia IEEE 802.11, com vantagem do ponto de vista do custo e da flexibilidade de instalação, face a soluções cabladas. Redes emalhadas sem fios constituídas por nós com apenas uma interface têm escalabilidade reduzida. A principal razão dessa limitação deve-se ao uso do mecanismo de acesso ao meio partilhado Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) em topologias multi-hop. Especificamente, o CSMA/CA não evita o problema do nó escondido levando ao aumento do número de colisões e correspondente degradação de desempenho com impacto direto no throughput e na latência. Com a redução da tecnologia rádio torna-se viável a utilização de múltiplos rádios por nó, sem com isso aumentar significativamente o custo da solução final de comunicações. A utilização de mais do que um rádio por nó de comuniações permite superar os problemas de desempenho inerentes ás redes formadas por nós com apenas um rádio. O objetivo desta tese, passa por desenvolver uma nova solução para redes emalhadas multi-cana, duar-radio, utilizando para isso novos mecanismos que complementam os mecanismos definidos no IEEE 802.11 para o estabelecimento de um Basic Service Set (BSS). A solução é baseada na solução WiFIX, um protocolo de routing para redes emalhadas de interface única e reutiliza os mecanismos já implementados nas redes IEEE 802.11 para difundir métricas que permitam à rede escalar de forma eficaz minimizando o impacto na performance. A rede multi-hop é formada por nós equipados com duas interfaces, organizados numa topologia hierárquica sobre múltiplas relações Access Point (AP) – Station (STA). Os resultados experimentais obtidos mostram a eficácia e o bom desempenho da solução proposta face à solução WiFIX original.

Right to asylum and border control : implications of european union policies on access to EU territory of people in need of international protection

Depuis plusieurs années, les États membres de l’Union européenne (UE) se soumettent à des politiques restrictives, en matière d’asile, qui les contraignent à respecter leur engagement de protéger les personnes qui fuient la persécution. Plusieurs politiques de dissuasion de l’UE sont controversées. Certaines ont d’abord été élaborées dans différents États, avant que l’UE ne mette en place une politique commune en matière d’asile. Certaines des ces politiques migratoires ont été copiées, et ont un effet négatif sur la transformation des procédures d’asile et du droit des réfugiés dans d’autres pays, tel le Canada. En raison des normes minimales imposées par la législation de l’UE, les États membres adoptent des politiques et instaurent des pratiques, qui sont mises en doute et sont critiquées par l’UNHCR et les ONG, quant au respect des obligations internationales à l'égard des droits de la personne. Parmi les politiques et les pratiques les plus critiquées certaines touchent le secteur du contrôle frontalier. En tentant de remédier à l’abolition des frontières internes, les États membres imposent aux demandeurs d’asile des barrières migratoires quasi impossibles à surmonter. Les forçant ainsi à s’entasser dans des centres de migration, au nord de l’Afrique, à rebrousser chemin ou encore à mourir en haute mer.

The expression and production of piano timbre : gestural control and technique, perception and verbalisation in the context of piano performance and practice

La version intégrale de cette thèse est disponible uniquement pour consultation individuelle à la Bibliothèque de musique de l’Université de Montréal (http://www.bib.umontreal.ca/MU).