108 research outputs found
Approximation algorithms for mobile multi-agent sensing problem
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곡νκ³Ό, 2020. 8. λ¬ΈμΌκ²½.Multi-agent systems are generally applicable in a wide diversity of domains, such as robot engineering, computer science, the military, and smart cities. In particular, the mobile multi-agent sensing problem can be defined as a problem of detecting events occurring in a large number of nodes using moving agents. In this thesis, we introduce a mobile multi-agent sensing problem and present a mathematical formulation. The model can be represented as a submodular maximization problem under a partition matroid constraint, which is NP-hard in general. The optimal solution of the model can be considered computationally intractable. Therefore, we propose two approximation algorithms based on the greedy approach, which are global greedy and sequential greedy algorithms, respectively. We present new approximation ratios of the sequential greedy algorithm and prove tightness of the ratios. Moreover, we show that the sequential greedy algorithm is competitive with the global greedy algorithm and has advantages of computation times. Finally, we demonstrate the performances of our results through numerical experiments.λ€μ€ μμ΄μ νΈ μμ€ν
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νκ³ κ·Όμ¬ λΉμ¨μ μ ννκ² μΌμΉνλ μΈμ€ν΄μ€λ₯Ό μ μνλ€. λν, μμΉ μ€ν κ²°κ³Όλ‘ μμ°¨ νμ μκ³ λ¦¬μ¦μ ν¨κ³Όμ μΈ ν΄λ₯Ό μ°Ύμμ€ λΏ μλλΌ, μ μ νμ μκ³ λ¦¬μ¦κ³Ό λΉκ΅ν΄ κ³μ° μκ°μ μ΄μ μ κ°μ§κ³ μμμ νμΈνλ€.Chapter 1 Introduction 1
Chapter 2 Literature Review 4
Chapter 3 Problem statement 7
Chapter 4 Algorithms and approximation ratios 11
Chapter 5 Computational Experiments 22
Chapter 6 Conclusions 30
Bibliography 31
κ΅λ¬Έμ΄λ‘ 40Maste
A k-hop Collaborate Game Model: Extended to Community Budgets and Adaptive Non-Submodularity
Revenue maximization (RM) is one of the most important problems on online
social networks (OSNs), which attempts to find a small subset of users in OSNs
that makes the expected revenue maximized. It has been researched intensively
before. However, most of exsiting literatures were based on non-adaptive
seeding strategy and on simple information diffusion model, such as
IC/LT-model. It considered the single influenced user as a measurement unit to
quantify the revenue. Until Collaborate Game model appeared, it considered
activity as a basic object to compute the revenue. An activity initiated by a
user can only influence those users whose distance are within k-hop from the
initiator. Based on that, we adopt adaptive seed strategy and formulate the
Revenue Maximization under the Size Budget (RMSB) problem. If taking into
account the product's promotion, we extend RMSB to the Revenue Maximization
under the Community Budget (RMCB) problem, where the influence can be
distributed over the whole network. The objective function of RMSB and RMCB is
adatpive monotone and not adaptive submodular, but in some special cases, it is
adaptive submodular. We study the RMSB and RMCB problem under both the speical
submodular cases and general non-submodular cases, and propose RMSBSolver and
RMCBSolver to solve them with strong theoretical guarantees, respectively.
Especially, we give a data-dependent approximation ratio for RMSB problem under
the general non-submodular cases. Finally, we evaluate our proposed algorithms
by conducting experiments on real datasets, and show the effectiveness and
accuracy of our solutions
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