8 research outputs found
Public survey instruments for business administration using social network analysis and big data
Purpose: The subject matter of this research is closely intertwined with the scientific discussion about the necessity of developing and implementing practice-oriented means of measuring social well-being taking into account the intensity of contacts between individuals. The aim of the research is to test the toolkit for analyzing social networks and to develop a research algorithm to identify sources of consolidation of public opinion and key agents of influence. The research methodology is based on postulates of sociology, graph theory, social network analysis and cluster analysis. Design/Methodology/Approach: The basis for the empirical research was provided by the data representing the reflection of social media users on the existing image of Russia and its activities in the Arctic, chosen as a model case. Findings: The algorithm allows to estimate the density and intensity of connections between actors, to trace the main channels of formation of public opinion and key agents of influence, to identify implicit patterns and trends, to relate information flows and events with current information causes and news stories for the subsequent formation of a "cleansed" image of the object under study and the key actors with whom this object is associated. Practical Implications: The work contributes to filling the existing gap in the scientific literature, caused by insufficient elaboration of the issues of applying the social network analysis to solve sociological problems. Originality/Value: The work contributes to filling the existing gap in the scientific literature formed as a result of insufficient development of practical issues of using analysis of social networks to solve sociological problems.peer-reviewe
Optimal Multiphase Investment Strategies for Influencing Opinions in a Social Network
We study the problem of optimally investing in nodes of a social network in a
competitive setting, where two camps aim to maximize adoption of their opinions
by the population. In particular, we consider the possibility of campaigning in
multiple phases, where the final opinion of a node in a phase acts as its
initial biased opinion for the following phase. Using an extension of the
popular DeGroot-Friedkin model, we formulate the utility functions of the
camps, and show that they involve what can be interpreted as multiphase Katz
centrality. Focusing on two phases, we analytically derive Nash equilibrium
investment strategies, and the extent of loss that a camp would incur if it
acted myopically. Our simulation study affirms that nodes attributing higher
weightage to initial biases necessitate higher investment in the first phase,
so as to influence these biases for the terminal phase. We then study the
setting in which a camp's influence on a node depends on its initial bias. For
single camp, we present a polynomial time algorithm for determining an optimal
way to split the budget between the two phases. For competing camps, we show
the existence of Nash equilibria under reasonable assumptions, and that they
can be computed in polynomial time
Optimal multiphase investment strategies for influencing opinions in a social network
International audienceWe study the problem of two competing camps aiming to maximize the adoption of their respective opinions, by optimally investing in nodes of a social network in multiple phases. The final opinion of a node in a phase acts as its biased opinion in the following phase. Using an extension of Friedkin-Johnsen model, we formulate the camps' utility functions, which we show to involve what can be interpreted as multiphase Katz centrality. We hence present optimal investment strategies of the camps, and the loss incurred if myopic strategy is employed. Simulations affirm that nodes attributing higher weightage to bias necessitate higher investment in initial phase. The extended version of this paper analyzes a setting where a camp's influence on a node depends on the node's bias; we show existence and polynomial time computability of Nash equilibrium
Identifying Influential Agents In Social Systems
This dissertation addresses the problem of influence maximization in social networks. In- fluence maximization is applicable to many types of real-world problems, including modeling contagion, technology adoption, and viral marketing. Here we examine an advertisement domain in which the overarching goal is to find the influential nodes in a social network, based on the network structure and the interactions, as targets of advertisement. The assumption is that advertisement budget limits prevent us from sending the advertisement to everybody in the network. Therefore, a wise selection of the people can be beneficial in increasing the product adoption. To model these social systems, agent-based modeling, a powerful tool for the study of phenomena that are difficult to observe within the confines of the laboratory, is used. To analyze marketing scenarios, this dissertation proposes a new method for propagating information through a social system and demonstrates how it can be used to develop a product advertisement strategy in a simulated market. We consider the desire of agents toward purchasing an item as a random variable and solve the influence maximization problem in steady state using an optimization method to assign the advertisement of available products to appropriate messenger agents. Our market simulation 1) accounts for the effects of group membership on agent attitudes 2) has a network structure that is similar to realistic human systems 3) models inter-product preference correlations that can be learned from market data. The results on synthetic data show that this method is significantly better than network analysis methods based on centrality measures. The optimized influence maximization (OIM) described above, has some limitations. For instance, it relies on a global estimation of the interaction among agents in the network, rendering it incapable of handling large networks. Although OIM is capable of finding the influential nodes in the social network in an optimized way and targeting them for advertising, in large networks, performing the matrix operations required to find the optimized solution is intractable. To overcome this limitation, we then propose a hierarchical influence maximization (HIM) iii algorithm for scaling influence maximization to larger networks. In the hierarchical method the network is partitioned into multiple smaller networks that can be solved exactly with optimization techniques, assuming a generalized IC model, to identify a candidate set of seed nodes. The candidate nodes are used to create a distance-preserving abstract version of the network that maintains an aggregate influence model between partitions. The budget limitation for the advertising dictates the algorithmâs stopping point. On synthetic datasets, we show that our method comes close to the optimal node selection, at substantially lower runtime costs. We present results from applying the HIM algorithm to real-world datasets collected from social media sites with large numbers of users (Epinions, SlashDot, and WikiVote) and compare it with two benchmarks, PMIA and DegreeDiscount, to examine the scalability and performance. Our experimental results reveal that HIM scales to larger networks but is outperformed by degreebased algorithms in highly-connected networks. However, HIM performs well in modular networks where the communities are clearly separable with small number of cross-community edges. This finding suggests that for practical applications it is useful to account for network properties when selecting an influence maximization method
Supporting cooperation and coordination in open multi-agent systems
Cooperation and coordination between agents are fundamental processes for increasing
aggregate and individual benefit in open Multi-Agent Systems (MAS).
The increased ubiquity, size, and complexity of open MAS in the modern world
has prompted significant research interest in the mechanisms that underlie cooperative
and coordinated behaviour. In open MAS, in which agents join and
leave freely, we can assume the following properties: (i) there are no centralised
authorities, (ii) agent authority is uniform, (iii) agents may be heterogeneously
owned and designed, and may consequently have con
icting intentions and inconsistent
capabilities, and (iv) agents are constrained in interactions by a complex
connecting network topology. Developing mechanisms to support cooperative
and coordinated behaviour that remain effective under these assumptions
remains an open research problem.
Two of the major mechanisms by which cooperative and coordinated behaviour
can be achieved are (i) trust and reputation, and (ii) norms and conventions.
Trust and reputation, which support cooperative and coordinated
behaviour through notions of reciprocity, are effective in protecting agents from
malicious or selfish individuals, but their capabilities can be affected by a lack of
information about potential partners and the impact of the underlying network structure. Regarding conventions and norms, there are still a wide variety of
open research problems, including: (i) manipulating which convention or norm
a population adopts, (ii) how to exploit knowledge of the underlying network
structure to improve mechanism efficacy, and (iii) how conventions might be
manipulated in the middle and latter stages of their lifecycle, when they have
become established and stable.
In this thesis, we address these issues and propose a number of techniques
and theoretical advancements that help ensure the robustness and efficiency
of these mechanisms in the context of open MAS, and demonstrate new techniques
for manipulating convention emergence in large, distributed populations.
Specfically, we (i) show that gossiping of reputation information can mitigate
the detrimental effects of incomplete information on trust and reputation and reduce
the impact of network structure, (ii) propose a new model of conventions
that accounts for limitations in existing theories, (iii) show how to manipulate
convention emergence using small groups of agents inserted by interested
parties, (iv) demonstrate how to learn which locations in a network have the
greatest capacity to in
uence which convention a population adopts, and (v)
show how conventions can be manipulated in the middle and latter stages of
the convention lifecycle