We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

Wireless indoor positioning systems have become very popular in recent years. These systems have been successfully used in many applications such as asset tracking and inventory management. This paper provides an overview of the existing wireless indoor positioning solutions and attempts to classify different techniques and systems. Three typical location estimation schemes of triangulation, scene analysis, and proximity are analyzed. We also discuss location fingerprinting in detail since it is used in most current system or solutions. We then examine a set of properties by which location systems are evaluated, and apply this evaluation method to survey a number of existing systems. Comprehensive performance comparisons including accuracy, precision, complexity, scalability, robustness, and cost are presented.

Survey of Wireless Indoor Positioning Techniques and Systems

http://www.eecs.northwestern.edu/~peters/references/LocalizationTechniquesMaoAustralia.pdf

Wireless sensor network localization techniques

Recently, indoor positioning systems (IPSs) have been designed to provide location information of persons and devices. The position information enables location-based protocols for user applications. Personal networks (PNs) are designed to meet the users' needs and interconnect users' devices equipped with different communications technologies in various places to form one network. Location-aware services need to be developed in PNs to offer flexible and adaptive personal services and improve the quality of lives. This paper gives a comprehensive survey of numerous IPSs, which include both commercial products and research-oriented solutions. Evaluation criteria are proposed for assessing these systems, namely security and privacy, cost, performance, robustness, complexity, user preferences, commercial availability, and limitations.We compare the existing IPSs and outline the trade-offs among these systems from the viewpoint of a user in a PN.

/pdf/a-survey-of-indoor-positioning-systems-for-wireless-personal-49es17pk5j.pdf

A survey of indoor positioning systems for wireless personal networks

http://romisatriawahono.net/lecture/rm/survey/softcomputing/Boussaid%20-%20Optimization%20Metaheuristics%20-%202013.pdf

A survey on optimization metaheuristics

http://alpha.science.unitn.it/~brunato/pubblicazioni/ComNet.pdf

Statistical learning theory for location fingerprinting in wireless LANs

Reactive Search integrates sub-symbolic machine learning techniques into search heuristics for solving complex optimization problems. By automatically adjusting the working parameters, a reactive search self-tunes and adapts, effectively learning by doing until a solution is found. Intelligent Optimization, a superset of Reactive Search, concerns online and off-line schemes based on the use of memory, adaptation, incremental development of models, experimental algorithms applied to optimization, intelligent tuning and design of heuristics. Reactive Search and Intelligent Optimization is an excellent introduction to the main principles of reactive search, as well as an attempt to develop some fresh intuition for the approaches. The book looks at different optimization possibilities with an emphasis on opportunities for learning and self-tuning strategies. While focusing more on methods than on problems, problems are introduced wherever they help make the discussion more concrete, or when a specific problem has been widely studied by reactive search and intelligent optimization heuristics. Individual chapters cover reacting on the neighborhood; reacting on the annealing schedule; reactive prohibitions; model-based search; reacting on the objective function; relationships between reactive search and reinforcement learning; and much more. Each chapter is structured to show basic issues and algorithms; the parameters critical for the success of the different methods discussed; and opportunities and schemes for the automated tuning of these parameters. Anyone working in decision making in business, engineering, economics or science will find a wealth of information here.

/pdf/reactive-search-and-intelligent-optimization-tibwzqrevc.pdf

Reactive Search and Intelligent Optimization

Mobile computing adds a mostly unexplored dimension to data mining: user's position is a relevant piece of information, and recommendation systems, selecting and ranking links of interest to the user, have the opportunity to take location into account. In this paper a mobility-aware recommendation system that considers the location of the user to filter recommended links is proposed. To avoid the potential problems and costs of insertion by hand, a new middleware layer, the location broker, maintains a historic database of locations and corresponding links used in the past and develops models relating resources to their spatial usage pattern. These models are used to calculate a preference metric when the current user is asking for resources of interest. Mobility scenarios are described and analyzed in terms of possible user requirements. The features of the PILGRIM mobile recommendation system are outlined together with a preliminary experimental evaluation of different metrics.

PILGRIM: A location broker and mobility-aware recommendation system

The problem of finding a maximum clique in a graph is prototypical for many clustering and similarity problems; however, in many real-world scenarios, the classical problem of finding a complete subgraph needs to be relaxed to finding an almost complete subgraph, a so-called quasi-clique . In this work, we demonstrate how two previously existing definitions of quasi-cliques can be unified and how the resulting, more general quasi-clique finding problem can be solved by extending two state-of-the-art stochastic local search algorithms for the classical maximum clique problem. Preliminary results for these algorithms applied to both, artificial and real-world problem instances demonstrate the usefulness of the new quasi-clique definition and the effectiveness of our algorithms.

On Effectively Finding Maximal Quasi-cliques in Graphs

Detecting the user location is crucial in a wireless environment, not only for the choice of first-hop communication partners, but also for many auxiliary purposes: Quality of Service (availability of information in the right place for reduced congestion/delay, establishment of the optimal path), energy consumption, automated insertion of location-dependent info into a web query issued by a user (for example a tourist asking informations about a monument or a restaurant, a fireman approaching a disaster area) The technique we propose in our investigation tries to meet two main goals: transparency to the network and independence from the environment A user entering an environment (for instance a wireless-networked building) shall be able to use his own portable equipment to build a personal map of the environment without the system even noticing it Preliminary tests allow us to detect position on a map with an average uncertainty of two meters when using information gathered from three IEEE80211 access points in an indoor environment composed of many rooms on a 625sqm area Performance is expected to improve when more access points will be exploited in the test area Implementation of the same techniques on Bluetooth are also being studied

/pdf/transparent-location-fingerprinting-for-wireless-services-37ea3bqdey.pdf

Mauro Brunato

Papers

Statistical learning theory for location fingerprinting in wireless LANs

Reactive Search and Intelligent Optimization

PILGRIM: A location broker and mobility-aware recommendation system

On Effectively Finding Maximal Quasi-cliques in Graphs

Transparent Location Fingerprinting for Wireless Services