An ad hoc network is formed by a group of self-configuring nodes, typically deployed in two or three dimensional spaces, and communicating with each other through wireless or some other media. The distinct characteristics of ad hoc networks include the lack of pre-designed infrastructure, the natural correlation between the network topology and geometry, and limited communication and computation resources. These characteristics introduce new challenges and opportunities for de- signing ad hoc network applications. This dissertation studies various optimization problems in ad hoc network information retrieval and transmission. Information stored in ad hoc networks is naturally associated with its location. To effectively retrieve such information, we study two fundamental problems, range search and object locating, from a distance sensitive point of view, where the retrieval cost depends on the distance between the user and the target information. We develop a general framework that is applicable to both problems for optimizing the storage overhead while maintaining the distance sensitive retrieval requirement. In addition, we derive a lowerbound result for the object locating problem which shows that logarithmic storage overhead is asymptotically optimal to achieve linear retrieval cost for growth bounded networks. Bandwidth is a scarce resource for wireless ad hoc networks, and its proper utilization is crucial to effective information transmission. To avoid conflict of wireless transmissions, links need to be carefully scheduled to satisfy various constraints. In this part of the study, we first consider an optimization problem of end-to-end on- demand bandwidth allocation with the single transceiver constraint. We study its complexity and present a 2-approximation algorithm. We then discuss how to estimate the end-to-end throughput under a widely adopted model for radio signal interference. A method based on identifying certain clique patterns is proposed and shown to have good practical performance.

As effective routing is critical in mobile ad hoc networks (MANETs), the Ad Hoc On-demand Distance Vector (AODV) has been extensively studied in recent years. AODV is a single path routing protocol that requires a new route discovery procedure whenever a link breaks, such frequent route discoveries incur a high routing overhead and increase end-to-end delay. Therefore, by modifying the AODV protocol, this work presents a novel backup routing scheme capable of repairing disrupted links locally without activating a route re-discovery procedure. Additionally, backup paths are established based on 2-hop neighbor knowledge. These backup paths are geographically close to the primary path in order to provide efficient recovery from route failure and maintain an adequate routing length. Simulation results indicate that the proposed backup routing scheme obtains a lower average end-to-end delay and less routing overhead than those of the Ad hoc On-demand Multipath Distance Vector (AOMDV) and the conventional AODV.

<p>Mitt examensarbete handlar om koncentrationssvårigheter. Att vara koncentrerad är inte det lättaste, under en hel dag måste eleven koncentrera sig på många olika saker. Eleven måste även lära sig att koppla bort vissa ljud och händelser för att kunna koncentrera sig på det den håller på med. Att hjälpa elever med koncentrationssvårigheter behöver inte vara komplicerat, det handlar om att göra undervisningen mer enkel och konkret. Koncentrationssvårigheter kan bero på många olika faktorer som till exempel miljön runt omkring eleven eller rent biologiska orsaker. För att komma fram till mitt resultat har jag intervjuat lärare och pedagoger samt observerat elever i olika åldrar på olika skolor. Det har givit mig en bra grund att stå på när jag sedan skrivit mitt arbete. I dagens skolor anser många lärare och pedagoger att det blir fler och fler elever som får koncentrationssvårigheter, frågan är om det verkligen är så? Är det en sådan ökning idag jämfört med hur det var förr eller är problemet bara mer uppmärksammat i dagens skola? Elever behöver inte få en diagnos för att ha koncentrationssvårigheter. För att få en diagnos krävs en viss problematik och detta uppfyller inte alla elever som har svårt att koncentrera sig. Alla elever har olika förutsättningar i skolan därför är det viktigt att vi som lärare och pedagoger kan ge dem den hjälp de behöver.</p>

Thèse de doctorat--Informatique et réseaux--Paris--ENST, 2006. / Bibliogr. p. 165-175. Glossaire. Résumé en anglais et en français.

Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Computer Science." Includes bibliographical references (p. 113-121).

Zugl.: Halle, Wittenberg, Univ., Diss., 2007

Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on June 27, 2009). Includes bibliographical references (p. 59-60).

Thesis (Ph.D.) -- University of Texas at Arlington, 2008.

Given the continuing improvements in design and manufacturing processes in addition to improvements in artificial intelligence, robots are being deployed in an increasing variety of environments for longer periods of time. As the number of robots grows, it is expected that they will encounter and interact with other robots. Additionally, the number of companies and research laboratories producing these robots is increasing, leading to the situation where these robots may not share a common communication or coordination protocol. While standards for coordination and communication may be created, we expect that any standards will lag behind the state-of-the-art protocols and robots will need to additionally reason intelligently about their teammates with limited information. This problem motivates the area of ad hoc teamwork in which an agent may potentially cooperate with a variety of teammates in order to achieve a shared goal. We argue that agents that effectively reason about ad hoc teamwork need to exhibit three capabilities: 1) robustness to teammate variety, 2) robustness to diverse tasks, and 3) fast adaptation. This thesis focuses on addressing all three of these challenges. In particular, this thesis introduces algorithms for quickly adapting to unknown teammates that enable agents to react to new teammates without extensive observations. The majority of existing multiagent algorithms focus on scenarios where all agents share coordination and communication protocols. While previous research on ad hoc teamwork considers some of these three challenges, this thesis introduces a new algorithm, PLASTIC, that is the first to address all three challenges in a single algorithm. PLASTIC adapts quickly to unknown teammates by reusing knowledge it learns about previous teammates and exploiting any expert knowledge available. Given this knowledge, PLASTIC selects which previous teammates are most similar to the current ones online and uses this information to adapt to their behaviors. This thesis introduces two instantiations of PLASTIC. The first is a model-based approach, PLASTIC-Model, that builds models of previous teammates' behaviors and plans online to determine the best course of action. The second uses a policy-based approach, PLASTIC-Policy, in which it learns policies for cooperating with past teammates and selects from among these policies online. Furthermore, we introduce a new transfer learning algorithm, TwoStageTransfer, that allows transferring knowledge from many past teammates while considering how similar each teammate is to the current ones. We theoretically analyze the computational tractability of PLASTIC-Model in a number of scenarios with unknown teammates. Additionally, we empirically evaluate PLASTIC in three domains that cover a spread of possible settings. Our evaluations show that PLASTIC can learn to communicate with unknown teammates using a limited set of messages, coordinate with externally-created teammates that do not reason about ad hoc teams, and act intelligently in domains with continuous states and actions. Furthermore, these evaluations show that TwoStageTransfer outperforms existing transfer learning algorithms and enables PLASTIC to adapt even better to new teammates. We also identify three dimensions that we argue best describe ad hoc teamwork scenarios. We hypothesize that these dimensions are useful for analyzing similarities among domains and determining which can be tackled by similar algorithms in addition to identifying avenues for future research. The work presented in this thesis represents an important step towards enabling agents to adapt to unknown teammates in the real world. PLASTIC significantly broadens the robustness of robots to their teammates and allows them to quickly adapt to new teammates by reusing previously learned knowledge. / text

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / A substantial amount of the energy usage in developed countries is consumed by climate control of residential and commercial structures. Collecting information on the usage patterns of heating, ventilation and air conditioning (HVAC) systems can allow a consumer to better understand the cost and effectiveness of these systems, and allow landlords and others to monitor their use. This paper describes a system which can easily be retrofitted onto legacy HVAC systems to monitor their activity, and then transmit the information over a wireless radio network for archiving and analysis