Given two sets of points $A$ and $B$ ($|A| = m$, $|B| = n$), we seek to find a minimum-weight many-to-many matching which seeks to match each point in $A$ to at least one point in $B$ and vice versa. Each matched pair (an edge) has a weight. The goal is to find the matching that minimizes the total weight. We study two kinds of problems depending on the edge weight used. The first edge weight is the Euclidean distance, $d_1$. The second is edge weight is the square of the Euclidean distance, $d_2$. There already exists an $O(k\log k)$ algorithm for $d_1$, where $k=m+n$. We provide an $O(mn)$ algorithm for the $d_2$ problem. We also solve the problem of finding the minimum-weight matching when the sets $A$ and $B$ are allowed to be translated on the real line. We present an $O(mnk \log k)$ algorithm for the $d_1$ problem and an $O(3^{mn})$ algorithm for the $d_2$. Furthermore, we also deal with the special case where $A$ and $B$ lie on a circle of a specific circumference. We present an $O(k^2 \log k)$ algorithm and $O(kmn)$ algorithm for solving the minimum-weight matching for the $d_1$, and $d_2$ weights respectively. Much like the problem on the real line, we extend this problem to allow the sets $A$ and $B$ to be rotated on the circle. We try to find the minimum-weight many-to-many matching when rotations are allowed. For $d_1$ we present an $O(k^2mn \log k)$ algorithm and a $O(3^{mn})$ algorithm for $d_2$. / Thesis (Master, Computing) -- Queen's University, 2010-11-08 20:48:18.968

Implementing an effective social media marketing strategy campaign to engage customers and increase sales is a challenge for owners of small retail business owners The purpose of this multiple case study was to explore the social media marketing strategies owners of small retail businesses used to increase sales. The conceptual framework for this study was the social media marketing strategy theory. Data were collected from 5 small retail business owners in North Carolina through semistructured, face-to-face interviews and a review of company documents, websites, and social media sites. Data analysis through Yin's 5-step process of compiling, disassembling, reassembling, interpreting, and concluding data resulted in 3 emergent themes: social media engagement strategy, outsourcing strategy, and target market strategy. Owners of small retail businesses might benefit from the findings of this study to increase sales by understanding how to integrate a mix of social media marketing platforms, improve customer engagement, use third-party social media experts to improve advertising, and target customers using social media. The implications of this study for positive social change include the potential for small business owners to increase job opportunities, lower local unemployment rates, and improve local economic growth and stability.

Um dos principais desafios em Redes Centradas em Informação (ICN) é como prover controle de acesso à publicação e recuperação de conteúdos. Apesar das potencialidades, as soluções existentes, geralmente, consideram um único usuário agindo como publicador. Ao lidar com múltiplos publicadores, elas podem levar a uma explosão combinatória de chaves criptográficas. As soluções projetadas visando a múltiplos publicadores, por sua vez, dependem de arquiteturas de redes específicas e/ou de mudanças nessas para operar. Nesta dissertação é proposta uma solução, apoiada em criptografia baseada em atributos, para controle de acesso a conteúdos. Nessa solução, o modelo de segurança é voltado a grupos de compartilhamento seguro, nos quais todos os usuários membros podem publicar e consumir conteúdos. Diferente de trabalhos anteriores, a solução proposta mantém o número de chaves proporcional ao de membros nos grupos e pode ser empregada em qualquer arquitetura ICN de forma gradual. A proposta é avaliada quanto ao custo de operação, à quantidade de chaves necessárias e à eficiência na disseminação de conteúdos. Em comparação às soluções existentes, ela oferece maior flexibilidade no controle de acesso, sem aumentar a complexidade do gerenciamento de chaves e sem causar sobrecustos significativos à rede. / One of the main challenges in Information-Centric Networking (ICN) is providing access control to content publication and retrieval. In spite of the potentialities, existing solutions often consider a single user acting as publisher. When dealing with multiple publishers, they may lead to a combinatorial explosion of cryptographic keys. Those solutions that focus on multiple publishers, on the other hand, rely on specific network architectures and/or changes to operate. In this dissertation, it is proposed a solution, supported by attribute-based encryption, for content access control. In this solution, the security model is focused on secure content distribution groups, in which any member user can publish to and retrieve from. Unlike previous work, the proposed solution keeps the number of cryptographic keys proportional to the number of group members, and may even be adopted gradually in any ICN architecture. The proposed solution is evaluated with respect to the overhead it imposes, number of required keys, and efficiency in the content dissemination. In contrast to existing solutions, it offers higher access control flexibility, without increasing key management process complexity and without causing significant network overhead.

Framväxten av en ny kundlogik, orsakad av teknikens framfart, har tvingat företag och organisationer att hitta nya tillvägagångssätt för att nå potentiella medlemmar eller kunder. Sociala medier är ett fenomen som har utvecklats från att vara ett kommunikationsverktyg för privatpersoner, till att bli ”ett nödvändigt ont” och en viktig del av marknadskommunikationen för många företag. Med denna uppsats vill vi utforska hur en ideell förening använder sociala medier för sin marknadsföring, vilka risker detta medför och vad som kan göras för att undvika dessa. Uppsatsen är en fallstudie som bygger på metodtriangulering och karaktäriseras av en abduktiv ansats. Studien baseras på två kvalitativa personliga intervjuer och en kvantitativ undersökning i form av enkät. Den teoretiska referensramen utgörs av word-of-mouth marketing, word-of-mouse marketing och many-to-many marketing.  Resultatet påvisar att fördelar med användandet av sociala medier för marknadsföring överträffar nackdelarna. För ideella organisationer borde nätverkande med hjälp av sociala medier vara en del av det vardagliga arbetet, både av ekonomiska och strategiska skäl. / The emergence of a new customer logic, caused by technological progress, has forced businesses to find new ways to reach potential members or customers. Social media is a phenomenon that has evolved from being a communication tool for individuals, to become a “necessary evil” and an important part of marketing communication for many businesses.  In this paper we explore how nonprofit organizations use social media in marketing, the risks involved in the process and what can be done to avoid these risks. The essay is a case study based on a quantitative survey and two qualitative interviews. The study shows that the benefits of the use of social media marketing surpass the disadvantages. For nonprofit organization, social media networking should be an integral part of the marketing efforts, for both economic and strategic reasons.

Today’s metropolitan areas see changes in populations and land development occurring at faster rates than transportation planning can be updated. This dissertation explores the use of a new dataset from the location-based social networking spectrum to analyze origin-destination travel demand within Austin, TX. A detailed exploration of the proposed data source is conducted to determine its overall capabilities with respect to the Austin area demographics. A new methodology is proposed for the creation of origin-destination matrices using a peer-to-peer modeling structure. This methodology is compared against a previously examined and more traditional approach, the doubly-constrained gravity model, to understand the capabilities of both models with various friction functions. Each method is examined within the constructs of the study area’s existing origin-destination matrix by examining the coincidence ratios, mean errors, mean absolute errors, frequency ratios, swap ratios, trip length distributions, zonal trip generation and attraction heat maps, and zonal origin-destination flow patterns. Through multiple measures, this dissertation provides initial interpretations of the robust Foursquare data collected for the Austin area. Based upon the data analytics performed, the Foursquare data source is shown to be capable of providing immensely detailed spatial-temporal data that can be utilized as a supplementary data source to traditional transportation planning data collection methods or in conjunction with other data sources, such as social networking platforms. The examination of the proposed peer-to-peer methodology presented within this dissertation provides a first look at the potential of many-to-many modeling for transportation planning. The peer-to-peer model was found to be superior to the doubly-constrained gravity model with respect to intrazonal trips. Furthermore, the peer-to-peer model was found to better estimate productions, attractions, and zone to zone movements when a linear function was used for long trips, and was computationally more proficient for all models examined.

Um dos principais desafios em Redes Centradas em Informação (ICN) é como prover controle de acesso à publicação e recuperação de conteúdos. Apesar das potencialidades, as soluções existentes, geralmente, consideram um único usuário agindo como publicador. Ao lidar com múltiplos publicadores, elas podem levar a uma explosão combinatória de chaves criptográficas. As soluções projetadas visando a múltiplos publicadores, por sua vez, dependem de arquiteturas de redes específicas e/ou de mudanças nessas para operar. Nesta dissertação é proposta uma solução, apoiada em criptografia baseada em atributos, para controle de acesso a conteúdos. Nessa solução, o modelo de segurança é voltado a grupos de compartilhamento seguro, nos quais todos os usuários membros podem publicar e consumir conteúdos. Diferente de trabalhos anteriores, a solução proposta mantém o número de chaves proporcional ao de membros nos grupos e pode ser empregada em qualquer arquitetura ICN de forma gradual. A proposta é avaliada quanto ao custo de operação, à quantidade de chaves necessárias e à eficiência na disseminação de conteúdos. Em comparação às soluções existentes, ela oferece maior flexibilidade no controle de acesso, sem aumentar a complexidade do gerenciamento de chaves e sem causar sobrecustos significativos à rede. / One of the main challenges in Information-Centric Networking (ICN) is providing access control to content publication and retrieval. In spite of the potentialities, existing solutions often consider a single user acting as publisher. When dealing with multiple publishers, they may lead to a combinatorial explosion of cryptographic keys. Those solutions that focus on multiple publishers, on the other hand, rely on specific network architectures and/or changes to operate. In this dissertation, it is proposed a solution, supported by attribute-based encryption, for content access control. In this solution, the security model is focused on secure content distribution groups, in which any member user can publish to and retrieve from. Unlike previous work, the proposed solution keeps the number of cryptographic keys proportional to the number of group members, and may even be adopted gradually in any ICN architecture. The proposed solution is evaluated with respect to the overhead it imposes, number of required keys, and efficiency in the content dissemination. In contrast to existing solutions, it offers higher access control flexibility, without increasing key management process complexity and without causing significant network overhead.

Um dos principais desafios em Redes Centradas em Informação (ICN) é como prover controle de acesso à publicação e recuperação de conteúdos. Apesar das potencialidades, as soluções existentes, geralmente, consideram um único usuário agindo como publicador. Ao lidar com múltiplos publicadores, elas podem levar a uma explosão combinatória de chaves criptográficas. As soluções projetadas visando a múltiplos publicadores, por sua vez, dependem de arquiteturas de redes específicas e/ou de mudanças nessas para operar. Nesta dissertação é proposta uma solução, apoiada em criptografia baseada em atributos, para controle de acesso a conteúdos. Nessa solução, o modelo de segurança é voltado a grupos de compartilhamento seguro, nos quais todos os usuários membros podem publicar e consumir conteúdos. Diferente de trabalhos anteriores, a solução proposta mantém o número de chaves proporcional ao de membros nos grupos e pode ser empregada em qualquer arquitetura ICN de forma gradual. A proposta é avaliada quanto ao custo de operação, à quantidade de chaves necessárias e à eficiência na disseminação de conteúdos. Em comparação às soluções existentes, ela oferece maior flexibilidade no controle de acesso, sem aumentar a complexidade do gerenciamento de chaves e sem causar sobrecustos significativos à rede. / One of the main challenges in Information-Centric Networking (ICN) is providing access control to content publication and retrieval. In spite of the potentialities, existing solutions often consider a single user acting as publisher. When dealing with multiple publishers, they may lead to a combinatorial explosion of cryptographic keys. Those solutions that focus on multiple publishers, on the other hand, rely on specific network architectures and/or changes to operate. In this dissertation, it is proposed a solution, supported by attribute-based encryption, for content access control. In this solution, the security model is focused on secure content distribution groups, in which any member user can publish to and retrieve from. Unlike previous work, the proposed solution keeps the number of cryptographic keys proportional to the number of group members, and may even be adopted gradually in any ICN architecture. The proposed solution is evaluated with respect to the overhead it imposes, number of required keys, and efficiency in the content dissemination. In contrast to existing solutions, it offers higher access control flexibility, without increasing key management process complexity and without causing significant network overhead.

E Pluribus Unum. La relation chez AristoteAristote déconstruit l’unité originaire des réalités à l’aide d’intelligibles en relation de plusieurs façons (relation indivisible, proportion, direction d’unification, assemblage de parties proportionnées entre elles, coïncidence). En donnant du volume à la pensée Aristote ouvre la voie de la connaissance de la complexité. Il ne faut pas hiérarchiser, voire opposer, la matière et l’esprit, l’ordre et le changement, l’unité et la pluralité, le déterminé et l’imprévisible, mais les mettre en relation. La relation, ce qui est partagé par plusieurs, est au cœur des « catégories » aussi bien que de l’unité « tout en un » des principes essentiels de l’étant. La relation seule n’explique pas l’être, mais l’être rend compte du fait que le mode de structuration des relations (séparabilité et indivisibilité) est un de ses principes premiers.Dans une première partie nous montrons qu’Aristote utilise toutes les topologies relationnelles, dont la relation de plusieurs à plusieurs propre aux réseaux.Dans la deuxième partie nous montrons comment sa notion d’être s’étudie à l’aide de la relation. L’être est une relation entre ses conditions d’existence impartageables (essentiel) et sa réalisation par des séparables (accidents). Aristote constate et analyse les principes (dimensions) de cette complexité, et il identifie que, pour penser les relations indivisibles (causes), l’homme possède un esprit immortel (le « noûs »). / E Pluribus Unum. The relation in Aristotle work’sAristotle studies unity as a complexity with several kinds of relationships. By doing so, he opens the way to the understanding of complexity. Our purpose is to study the different uses of relationship in Aristotle works. Relation is used from an accidental point of view (prós ti) as well as from an essential point of view (ousia), for the pros hén directionnal convergence and for the coïncidence of homonyms. Relationship fits with the “all-in-one” and pluri-dimensionnal approach of being by Aristotle. Relation alone is not being, but is part of being.In a first part we show that Aristotle uses each of the relation topologies in his studies, the many to many relationships used for networking is the base for Catégories.In the second part we show, from the major thesis of Aristotle, that a relational approach, coupled to directional finality and the prime motricity of each being, helps to understand the subject matter of what Aristotle is saying. Relation, because it is a first principle, helps to understand the role of all other principles used by Aristotle. Since man thinks unbreakable relations, it should possess an immortal “noûs”.

Collective Communication Operations are widely used in MPI applications and play an important role in their performance. Hence, various projects have focused on optimization of collective communications for various kinds of parallel computing environments including LAN settings, heterogeneous networks and most recently Grid systems. The distinguishing factor of Grids from all the other environments is heterogeneity of hosts and network, and dynamically changing resource characteristics including load and availability. The first part of the thesis develops a solution for MPI broadcast (one-to-many) on Grids. Some current strategies take into consideration static information about network topology for determining an efficient broadcast tree for Grids. Some other strategies take into account only transient network characteristics. We combined both these strategies and cluster the network dynamically on the basis of link bandwidths. Given a set of network parameters we use Simulated Annealing (SA) to obtain the best schedule. Also, we can time tune individual. SAs, to adapt the solution finding process, on the basis of estimated available times before next broadcast invocations in the application. We also developed software architecture for updation of schedules. We compared our algorithm with the earlier approaches under loaded network conditions, and obtained average performance improvement of 20%. The second part of the thesis extends the work for MPI all gather (many-to-many) operation. Current popular techniques consider strict hierarchical schemes for this operation, wherein from each cluster a representative (or coordinator) node is chosen, and inter cluster communication is done through these representative nodes. This is non optimal as inter cluster communication is usually on high capacity links that can sustain more than one transfer with the same through- put. We developed a cluster based and incremental heuristic algorithm for allgather on Grids. We compared the time taken by allgather schedules determined by this algorithm with current popular implementations. We also compared our algorithm with a strategy where allgather is constructed from a set of broadcast trees. We obtained average performance improvement of 67% over existing strategies.

This thesis consists of three independent papers. They are put in reverse chronological order according to when they were initiated. The first paper, which is a joint work with Özgür Evren, extends the standard rational choice framework with the option to postpone the act of selecting an alternative. In that paper, we propose an axiomatic model of choice over risky prospects that restricts the classical rationality axioms solely to those instances in which the decision maker does not defer. The cardinal approach we follow allows us to identify the preference relation of the decision maker over lotteries, even if the choice data is very scarce due to deferral. Moreover, we also derive the value of deferring choice from a given set of options, which turns out to be an affine utility function over choice sets. At each choice situation, the decision maker compares the utility of each available alternative with that of deferral so as to decide on opting for an alternative immediately. The second paper is a model of status quo bias with choice avoidance. It describes the choice behavior of an otherwise standard decision maker whose choices are affected by the presence of a status quo alternative. The status quo emerges as a temporary choice, which may be reversed upon arrival of new (introspective or objective) information, or upon finding new alternatives. The third paper considers the network formation problem from a matching perspective. In that paper, agents want to link with each other and each has preferences over the subsets of others. We consider various solution concepts regarding the stability of a matching between the agents, establish relations between these concepts under several preference restrictions, and provide sufficient conditions for these solutions to be nonempty. / Diss. Stockholm : Handelshögskolan i Stockholm, 2011