Hybrid graph convolutional networks with multi-head attention for location recommendation

World Wide Web - Recommending yet-unvisited points of interest (POIs) which may be of interest to users is one of the fundamental applications in location-based social networks. It mainly replies...     

Minimax regret 1-sink location problem in dynamic cycle networks

In this paper, we consider the minimax regret 1-sink location problem in a dynamic cycle network with positive edge lengths and uniform edge capacity. Let C be an undirected cycle graph of n vertices and n edges. Each edge has a positive edge length and a uniform edge capacity. Each vertex has a weight which is not known exactly but we know the interval it belongs to. The problem is to find a point x as the sink on the cycle and all weights evacuate to x   such that the maximum regret for all possible weight distributions is minimized. This paper presents an O(n³log?n)$O(n^3\log ?n)$ time algorithm.     

Noise-tolerance matrix completion for location recommendation

Due to the sharply increasing number of users and venues in Location-Based Social Networks, it becomes a big challenge to provide recommendations which match users’ preferences. Furthermore, the sparse data and skew distribution (i.e., structural noise) also worsen the coverage and accuracy of recommendations. This problem is prevalent in traditional recommender methods since they assume that the collected data truly reflect users’ preferences. To overcome the limitation of current recommenders, it is imperative to explore an effective strategy, which can accurately provide recommendations while tolerating the structural noise. However, few study concentrates on the process of noisy data in the recommender system, even recent matrix-completion algorithms. In this paper, we cast the location recommendation as a mathematical matrix-completion problem and propose a robust algorithm named Linearized Bregman Iteration for Matrix Completion (LBIMC), which can effectively recover the user-location matrix considering structural noise and provide recommendations based solely on check-in records. Our experiments are conducted by an amount of check-in data from Foursquare, and the results demonstrate the effectiveness of LBIMC.     

Aggregate nearest neighbor queries in road networks

Aggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points. Consider, for example, several users at specific locations (query points) that want to find the restaurant (data point), which leads to the minimum sum of distances that they have to travel in order to meet. We study the processing of such queries for the case where the position and accessibility of spatial objects are constrained by spatial (e.g., road) networks. We consider alternative aggregate functions and techniques that utilize Euclidean distance bounds, spatial access methods, and/or network distance materialization structures. Our algorithms are experimentally evaluated with synthetic and real data. The results show that their relative performance depends on the problem characteristics.     

Hub location for time definite transportation

Time definite motor carriers provide very reliable scheduled truck transportation service between specified terminals. They provide service competitive with airfreight carriers over continental-scale distances at a much lower cost. This paper provides time definite models for multiple allocation p-hub median problems and hub arc location problems. Service levels are imposed by limiting the maximum travel distance via the hub network for each origin–destination pair. Computational results are presented to demonstrate the effects of the time definite service levels on practical network design for truck transportation in North America.     

The dynamic competitive recommendation algorithm in social network services

As the number of Twitter users exceeds 175 million and the scale of social network increases, it is facing with a challenge to how to help people find right people and information conveniently. For this purpose, current social network services are adopting personalized recommender systems. Existing recommendation algorithms largely depend on one of content-based algorithm, collaborative filtering, or influential ranking analysis. However, these algorithms tend to suffer from the performance fluctuation phenomenon in common whenever an active user changes, and it is due to the diversities of personal characteristics such as the local social graph size, the number of followers, or sparsity of profile content. To overcome this limitation and to provide consistent and stable recommendation in social networks, this study proposes the dynamic competitive recommendation algorithm based on the competition of multiple component algorithms. This study shows that it outperforms previous approaches through performance evaluation on actual Twitter dataset.     

Multi-agent location system in wireless networks

In this paper we propose a flexible Multi-Agent Architecture together with a methodology for indoor location which allows us to locate any mobile station (MS) such as a Laptop, Smartphone, Tablet or a robotic system in an indoor environment using wireless technology. Our technology is complementary to the GPS location finder as it allows us to locate a mobile system in a specific room on a specific floor using the Wi-Fi networks.The idea is that any MS will have an agent known at a Fuzzy Location Software Agent (FLSA) with a minimum capacity processing at its disposal which collects the power received at different Access Points distributed around the floor and establish its location on a plan of the floor of the building. In order to do so it will have to communicate with the Fuzzy Location Manager Software Agent (FLMSA). The FLMSAs are local agents that form part of the management infrastructure of the Wi-Fi network of the Organization.The FLMSA implements a location estimation methodology divided into three phases (measurement, calibration and estimation) for locating mobile stations (MS). Our solution is a fingerprint-based positioning system that overcomes the problem of the relative effect of doors and walls on signal strength and is independent of the network device manufacturer.In the measurement phase, our system collects received signal strength indicator (RSSI) measurements from multiple access points. In the calibration phase, our system uses these measurements in a normalization process to create a radio map, a database of RSS patterns. Unlike traditional radio map-based methods, our methodology normalizes RSS measurements collected at different locations on a floor. In the third phase, we use Fuzzy Controllers to locate an MS on the plan of the floor of a building.Experimental results demonstrate the accuracy of the proposed method. From these results it is clear that the system is highly likely to be able to locate an MS in a room or adjacent room.     

Flickr group recommendation with auxiliary information in heterogeneous information networks

Over the past few years, the appropriate utilization of user communities or image groups in social networks (i.e., Flickr or Facebook) has drawn a great deal of attention. In this paper, we are particularly interested in recommending preferred groups to users who may favor according to auxiliary information. In real world, the images captured by mobile equipments explicitly record a lot of contextual information (e.g., locations) about users generating images. Meanwhile, several words are employed to describe the particular theme of each group (e.g., “Dogs for Fun Photos” image group in Flickr), and the words may mention particular entities as well as their belonging categories (e.g., “Animal”). In fact, the group recommendation can be conducted in heterogeneous information networks, where informative cues are in general multi-typed. Motivated by the assumption that the auxiliary information (visual features of images, mobile contextual information and entity-category information of groups in this paper) in heterogeneous information networks will boost the performance of the group recommendation, this paper proposes to combine auxiliary information with implicit user feedback for group recommendation. In general, the group recommendation in this paper is formulated as a non-negative matrix factorization (NMF) method regularized with user–user similarity via visual features and heterogeneous information networks. Experiments show that our proposed approach outperforms other counterpart recommendation approaches.     

Topic-tracking-based dynamic user modeling with TV recommendation applications

One of the challenging issues in TV recommendation applications based on implicit rating data is how to make robust recommendation for the users who irregularly watch TV programs and for the users who have their time-varying preferences on watching TV programs. To achieve the robust recommendation for such users, it is important to capture dynamic behaviors of user preference on watched TV programs over time. In this paper, we propose a topic tracking based dynamic user model (TDUM) that extends the previous multi-scale dynamic topic model (MDTM) by incorporating topic-tracking into dynamic user modeling. In the proposed TDUM, the prior of the current user preference is estimated as a weighted combination of the previously learned preferences of a TV user in multi-time spans where the optimal weight set is found in the sense of the evidence maximization of the Bayesian probability. So, the proposed TDUM supports the dynamics of public users’ preferences on TV programs for collaborative filtering based TV program recommendation and the highly ranked TV programs by similar watching taste user group (topic) can be traced with the same topic labels epoch by epoch. We also propose a rank model for TV program recommendation. In order to verify the effectiveness of the proposed TDUM and rank model, we use a real data set of the TV programs watched by 1,999 TV users for 7 months. The experiment results demonstrate that the proposed TDUM outperforms the Latent Dirichlet Allocation (LDA) model and the MDTM in log-likelihood for the topic modeling performance, and also shows its superiority compared to LDA, MDTM and Bayesian Personalized Rank Matrix Factorization (BPRMF) for TV program recommendation performance in terms of top-N precision-recall.     

Broadcasting in dynamic radio networks

It is reasonable to claim that almost all major questions related to radio broadcasting can be considered closed as far as static networks are considered: the network never changes during the entire protocol's execution. On the other hand, theoretical results on communication protocols in any scenario where the network topology may change during protocol's execution (i.e. a dynamic radio network) are very few.In this paper, we present a theoretical study of broadcasting in radio networks having dynamic unknown topology. The dynamic network is modeled by means of adversaries: we consider two of them. We first analyze an oblivious, memoryless random adversary that can be seen as the dynamic version of the average-case study presented by Elsässer and Gasieniec in JCSS, 2006. We then consider the deterministic worst-case adversary that, at each time slot, can make any network change (thus the strongest adversary). This is the dynamic version of the worst-case study provided by Bar-Yehuda, Goldreich and Itai in JCSS, 1992.In both cases we provide tight bounds on the completion time of randomized broadcast protocols.     

Spectral evolution in dynamic networks

We introduce and study the spectral evolution model, which characterizes the growth of large networks in terms of the eigenvalue decomposition of their adjacency matrices: In large networks, changes over time result in a change of a graph’s spectrum, leaving the eigenvectors unchanged. We validate this hypothesis for several large social, collaboration, rating, citation, and communication networks. Following these observations, we introduce two link prediction algorithms based on the learning of the changes to a network’s spectrum. These new link prediction methods generalize several common graph kernels that can be expressed as spectral transformations. The first method is based on reducing the link prediction problem to a one-dimensional curve-fitting problem which can be solved efficiently. The second algorithm extrapolates a network’s spectrum to predict links. Both algorithms are evaluated on fifteen network datasets for which edge creation times are known.     

Search on transportation networks for location-based service

The issue of how to provide location-based service (LBS) attracted many researchers. In this paper, we focus on a typical situation of LBS which is to provide services for users in cars that move in a road network. To provide such kind of services, an integration method for representing transportation information with a road map is proposed. By using our integration method, since the transportation information of road networks is managed under the spatial index structure created for road networks, spatial queries on them can take advantages of the spatial index structure and achieve an efficient process. Moreover, we discuss path search, region search, nearest neighbor search and continuous nearest neighbor search in this paper, which are based on transportation networks with (or without) considering the static spatial objects outside the transportation networks. Using transportation information and the corresponding real road network, the paper offers evaluations by comparing our representation method and query method with those in related works. The results show a good performance of our methods.     

Presenting a hybrid model in social networks recommendation system architecture development

There are many studies conducted on recommendation systems, most of which are focused on recommending items to users and vice versa. Nowadays, social networks are complicated due to carrying vast arrays of data about individuals and organizations. In today’s competitive environment, companies face two significant problems: supplying resources and attracting new customers. Even the concept of supply-chain management in a virtual environment is changed. In this article, we propose a new and innovative combination approach to recommend organizational people in social networks based on organizational communication and SCM. The proposed approach uses a hybrid strategy that combines basic collaborative filtering and demographic recommendation systems, using data mining, artificial neural networks, and fuzzy techniques. The results of experiments and evaluations based on a real dataset collected from the LinkedIn social network showed that the hybrid recommendation system has higher accuracy and speed than other essential methods, even substantially has eliminated the fundamental problems with such systems, such as cold start, scalability, diversity, and serendipity.

     

Multimedia content recommendation in social networks using mood tags and synonyms

Multimedia Systems - The preferences of Web information purchasers are changing. Cost-effectiveness (i.e., an emphasis on performance with respect to price) is becoming less regarded than...     

无线传感器网络在智能交通中的应用

针对目前中国的交叉路口多、车流量大、交通混乱等现象,阐述了基于无线传感器网络的智能交通系统的基本原理。结合国内外将无线传感器网络应用于智能交通网系统的已有研究应用情况,指出了无线传感器网络技术应用于智能交通中的交通信息采集、交通信息传输、交通控制和诱导等方面的几个关键技术,以便为进一步研究并拓展无线传感器网络在智能交通中的应用提供参考。     

Neural networks for analyzing service quality in public transportation

It is essential to take into account the service quality assessment made by the passengers of a public transportation system, as well as the weight or relative importance assigned to each one of the attributes considered, in order to know its strengths and weaknesses. This paper proposes using Artificial Neural Networks (ANN) to analyze the service quality perceived by the passengers of a public transportation system. This technique is characterized by its high capability for prediction and for capturing highly non-lineal intrinsic relations between the study variables without requiring a pre-defined model. First, an ANN model was developed using the data gathered in a Customer Satisfaction Survey conducted on the Granada bus metropolitan transit system in 2007. Next, three different methods were used to determine the relative contribution of the attributes. Finally, a statistical analysis was applied to the outcomes of each method to identify groups of attributes with significant differences in their relative importance. The results show that statistical significant differences exist among several categories of attributes that have a greater or lesser impact on service quality and satisfaction. All the methods agree that Frequency is the most influential attribute in the service quality, and that other attributes such as Speed, Information and Proximity are also important.     

A collaborative filtering recommendation system with dynamic time decay

The Journal of Supercomputing - The collaborative filtering (CF) technique has been widely utilized in recommendation systems due to the precise prediction of users' interests. Most prior CF...