188 research outputs found
Adaptive fault-tolerant routing in hypercube multicomputers
A connected hypercube with faulty links and/or nodes is called an injured hypercube. To enable any non-faulty node to communicate with any other non-faulty node in an injured hypercube, the information on component failures has to be made available to non-faulty nodes so as to route messages around the faulty components. A distributed adaptive fault tolerant routing scheme is proposed for an injured hypercube in which each node is required to know only the condition of its own links. Despite its simplicity, this scheme is shown to be capable of routing messages successfully in an injured hypercube as long as the number of faulty components is less than n. Moreover, it is proved that this scheme routes messages via shortest paths with a rather high probabiltiy and the expected length of a resulting path is very close to that of a shortest path. Since the assumption that the number of faulty components is less than n in an n-dimensional hypercube might limit the usefulness of the above scheme, a routing scheme is introduced based on depth-first search which works in the presence of an arbitrary number of faulty components. Due to the insufficient information on faulty components, the paths chosen by the above scheme may not always be the shortest. To guarantee that all messages be routed via shortest paths, it is proposed that every mode be equipped with more information than that on its own links. The effects of this additional information on routing efficiency are analyzed, and the additional information to be kept at each node for the shortest path routing is determined. Several examples and remarks are also given to illustrate the results
Scale-Adaptive Group Optimization for Social Activity Planning
Studies have shown that each person is more inclined to enjoy a group
activity when 1) she is interested in the activity, and 2) many friends with
the same interest join it as well. Nevertheless, even with the interest and
social tightness information available in online social networks, nowadays many
social group activities still need to be coordinated manually. In this paper,
therefore, we first formulate a new problem, named Participant Selection for
Group Activity (PSGA), to decide the group size and select proper participants
so that the sum of personal interests and social tightness of the participants
in the group is maximized, while the activity cost is also carefully examined.
To solve the problem, we design a new randomized algorithm, named Budget-Aware
Randomized Group Selection (BARGS), to optimally allocate the computation
budgets for effective selection of the group size and participants, and we
prove that BARGS can acquire the solution with a guaranteed performance bound.
The proposed algorithm was implemented in Facebook, and experimental results
demonstrate that social groups generated by the proposed algorithm
significantly outperform the baseline solutions.Comment: 20 pages. arXiv admin note: substantial text overlap with
arXiv:1305.150
Maximizing Friend-Making Likelihood for Social Activity Organization
The social presence theory in social psychology suggests that
computer-mediated online interactions are inferior to face-to-face, in-person
interactions. In this paper, we consider the scenarios of organizing in person
friend-making social activities via online social networks (OSNs) and formulate
a new research problem, namely, Hop-bounded Maximum Group Friending (HMGF), by
modeling both existing friendships and the likelihood of new friend making. To
find a set of attendees for socialization activities, HMGF is unique and
challenging due to the interplay of the group size, the constraint on existing
friendships and the objective function on the likelihood of friend making. We
prove that HMGF is NP-Hard, and no approximation algorithm exists unless P =
NP. We then propose an error-bounded approximation algorithm to efficiently
obtain the solutions very close to the optimal solutions. We conduct a user
study to validate our problem formulation and per- form extensive experiments
on real datasets to demonstrate the efficiency and effectiveness of our
proposed algorithm
Dual Adversarial Alignment for Realistic Support-Query Shift Few-shot Learning
Support-query shift few-shot learning aims to classify unseen examples (query
set) to labeled data (support set) based on the learned embedding in a
low-dimensional space under a distribution shift between the support set and
the query set. However, in real-world scenarios the shifts are usually unknown
and varied, making it difficult to estimate in advance. Therefore, in this
paper, we propose a novel but more difficult challenge, RSQS, focusing on
Realistic Support-Query Shift few-shot learning. The key feature of RSQS is
that the individual samples in a meta-task are subjected to multiple
distribution shifts in each meta-task. In addition, we propose a unified
adversarial feature alignment method called DUal adversarial ALignment
framework (DuaL) to relieve RSQS from two aspects, i.e., inter-domain bias and
intra-domain variance. On the one hand, for the inter-domain bias, we corrupt
the original data in advance and use the synthesized perturbed inputs to train
the repairer network by minimizing distance in the feature level. On the other
hand, for intra-domain variance, we proposed a generator network to synthesize
hard, i.e., less similar, examples from the support set in a self-supervised
manner and introduce regularized optimal transportation to derive a smooth
optimal transportation plan. Lastly, a benchmark of RSQS is built with several
state-of-the-art baselines among three datasets (CIFAR100, mini-ImageNet, and
Tiered-Imagenet). Experiment results show that DuaL significantly outperforms
the state-of-the-art methods in our benchmark.Comment: Best student paper in PAKDD 202
Progressive content-based retrieval of image and video with adaptive and iterative refinement
A method and apparatus for minimizing the time required to obtain results for a content based query in a data base. More specifically, with this invention, the data base is partitioned into a plurality of groups. Then, a schedule or sequence of groups is assigned to each of the operations of the query, where the schedule represents the order in which an operation of the query will be applied to the groups in the schedule. Each schedule is arranged so that each application of the operation operates on the group which will yield intermediate results that are closest to final results
When Social Influence Meets Item Inference
Research issues and data mining techniques for product recommendation and
viral marketing have been widely studied. Existing works on seed selection in
social networks do not take into account the effect of product recommendations
in e-commerce stores. In this paper, we investigate the seed selection problem
for viral marketing that considers both effects of social influence and item
inference (for product recommendation). We develop a new model, Social Item
Graph (SIG), that captures both effects in form of hyperedges. Accordingly, we
formulate a seed selection problem, called Social Item Maximization Problem
(SIMP), and prove the hardness of SIMP. We design an efficient algorithm with
performance guarantee, called Hyperedge-Aware Greedy (HAG), for SIMP and
develop a new index structure, called SIG-index, to accelerate the computation
of diffusion process in HAG. Moreover, to construct realistic SIG models for
SIMP, we develop a statistical inference based framework to learn the weights
of hyperedges from data. Finally, we perform a comprehensive evaluation on our
proposals with various baselines. Experimental result validates our ideas and
demonstrates the effectiveness and efficiency of the proposed model and
algorithms over baselines.Comment: 12 page
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