399 research outputs found
Building recognition on subregionās multi-scale gist feature extraction and corresponding columns information based dimensionality reduction
Peer reviewedPublisher PD
Multi-Perspective Relevance Matching with Hierarchical ConvNets for Social Media Search
Despite substantial interest in applications of neural networks to
information retrieval, neural ranking models have only been applied to standard
ad hoc retrieval tasks over web pages and newswire documents. This paper
proposes MP-HCNN (Multi-Perspective Hierarchical Convolutional Neural Network)
a novel neural ranking model specifically designed for ranking short social
media posts. We identify document length, informal language, and heterogeneous
relevance signals as features that distinguish documents in our domain, and
present a model specifically designed with these characteristics in mind. Our
model uses hierarchical convolutional layers to learn latent semantic
soft-match relevance signals at the character, word, and phrase levels. A
pooling-based similarity measurement layer integrates evidence from multiple
types of matches between the query, the social media post, as well as URLs
contained in the post. Extensive experiments using Twitter data from the TREC
Microblog Tracks 2011--2014 show that our model significantly outperforms prior
feature-based as well and existing neural ranking models. To our best
knowledge, this paper presents the first substantial work tackling search over
social media posts using neural ranking models.Comment: AAAI 2019, 10 page
Polylogarithmic Approximation Algorithm for k-Connected Directed Steiner Tree on Quasi-Bipartite Graphs
In the k-Connected Directed Steiner Tree problem (k-DST), we are given a directed graph G = (V,E) with edge (or vertex) costs, a root vertex r, a set of q terminals T, and a connectivity requirement k > 0; the goal is to find a minimum-cost subgraph H of G such that H has k edge-disjoint paths from the root r to each terminal in T. The k-DST problem is a natural generalization of the classical Directed Steiner Tree problem (DST) in the fault-tolerant setting in which the solution subgraph is required to have an r,t-path, for every terminal t, even after removing k-1 vertices or edges. Despite being a classical problem, there are not many positive results on the problem, especially for the case k ? 3. In this paper, we present an O(log k log q)-approximation algorithm for k-DST when an input graph is quasi-bipartite, i.e., when there is no edge joining two non-terminal vertices. To the best of our knowledge, our algorithm is the only known non-trivial approximation algorithm for k-DST, for k ? 3, that runs in polynomial-time Our algorithm is tight for every constant k, due to the hardness result inherited from the Set Cover problem
SSLRec: A Self-Supervised Learning Framework for Recommendation
Self-supervised learning (SSL) has gained significant interest in recent
years as a solution to address the challenges posed by sparse and noisy data in
recommender systems. Despite the growing number of SSL algorithms designed to
provide state-of-the-art performance in various recommendation scenarios (e.g.,
graph collaborative filtering, sequential recommendation, social
recommendation, KG-enhanced recommendation), there is still a lack of unified
frameworks that integrate recommendation algorithms across different domains.
Such a framework could serve as the cornerstone for self-supervised
recommendation algorithms, unifying the validation of existing methods and
driving the design of new ones. To address this gap, we introduce SSLRec, a
novel benchmark platform that provides a standardized, flexible, and
comprehensive framework for evaluating various SSL-enhanced recommenders. The
SSLRec framework features a modular architecture that allows users to easily
evaluate state-of-the-art models and a complete set of data augmentation and
self-supervised toolkits to help create SSL recommendation models with specific
needs. Furthermore, SSLRec simplifies the process of training and evaluating
different recommendation models with consistent and fair settings. Our SSLRec
platform covers a comprehensive set of state-of-the-art SSL-enhanced
recommendation models across different scenarios, enabling researchers to
evaluate these cutting-edge models and drive further innovation in the field.
Our implemented SSLRec framework is available at the source code repository
https://github.com/HKUDS/SSLRec.Comment: Published as a WSDM'24 full paper (oral presentation
Optimal Power Flow in Hybrid AC and Multi-terminal HVDC Networks with Offshore Wind Farm Integration Based on Semidefinite Programming
Multi-terminal high voltage direct current (MTHVDC) technology is a promising
technology for the offshore wind farm integration, which requires the new
control and operation scheme. Therefore, the optimal power flow problem for
this system is important to achieve the optimal economic operation. In this
paper, convex relaxation model based on semidefinite programming for the
MT-HVDC system considering DC/DC converters is proposed to solve the optimal
power flow problem. A hybrid AC and MT-HVDC system for offshore wind farm
integration is used for the test. The simulation results validate the
effectiveness of the proposed model and guarantee that the global optimum
solution is achieved.Comment: Accepted in IEEE/PES ISGT Asia 2019 conference (May, 2019), Chengdu,
Chin
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