User Preferences-Based and Time-Sensitive Location Recommendation Using Check-In Data

Location-based social networks have attracted increasing users in recent years. Human movements and mobility patterns have a high degree of freedom and provide us with a lot of trajectory to understand the activity of users. In this paper, we present?a user preferences and time sensitive recommender systems that offer an appropriate venue for a user when he appears in a special time at a particular location. The system considering the factors are: 1) the popularity of a location;2) the preferences of a user;3) social influence of the friends of the user and the friends who are check-in at the same location with the user;and 4) the time feature of the location and the user visiting. We evaluate our system with a large-scale real dataset from a location-based social network of Gowalla. The results confirm that our method provides more accurate location recommendations compared to the baseline.

A Fast Physical Layer Security-Based Location Privacy Parameter Recommendation Algorithm in 5G IoT

The 5G IoT(Internet of Things,IoT)is easier to implement in location privacy-preserving research.The terminals in distributed network architecture blur their accurate locations into a spatial cloaking region but most existing spatial cloaking algorithms cannot work well because of man-in-the-middle attacks,high communication overhead,time consumption,and the lower success rate.This paper proposes an algorithm that can recommend terminal’s privacy requirements based on getting terminal distribution information in the neighborhood after cross-layer authentication and therefore help 5G IoT terminals find enough collaborative terminals safely and quickly.The approach shows it can avoid man-in-the-middle attacks and needs lower communication costs and less searching time than 520ms at the same time.It has a great anonymization success rate by 93%through extensive simulation experiments for a range of 5G IoT scenarios.

Recommending Friends Instantly in Location-based Mobile Social Networks

Differently from the general online social network(OSN),locationbased mobile social network(LMSN),which seamlessly integrates mobile computing and social computing technologies,has unique characteristics of temporal,spatial and social correlation.Recommending friends instantly based on current location of users in the real world has become increasingly popular in LMSN.However,the existing friend recommendation methods based on topological structures of a social network or non-topological information such as similar user profiles cannot well address the instant making friends in the real world.In this article,we analyze users' check-in behavior in a real LMSN site named Gowalla.According to this analysis,we present an approach of recommending friends instantly for LMSN users by considering the real-time physical location proximity,offline behavior similarity and friendship network information in the virtual community simultaneously.This approach effectively bridges the gap between the offline behavior of users in the real world and online friendship network information in the virtual community.Finally,we use the real user check-in dataset of Gowalla to verify the effectiveness of our approach.

Location-Aware Personalized Traveler Recommender System(LAPTA)Using Collaborative Filtering KNN

Many tourists who travel to explore different cultures and cities worldwide aim to find the best tourist sites,accommodation,and food according to their interests.This objective makes it harder for tourists to decide and plan where to go and what to do.Aside from hiring a local guide,an option which is beyond most travelers’budgets,the majority of sojourners nowadays use mobile devices to search for or recommend interesting sites on the basis of user reviews.Therefore,this work utilizes the prevalent recommender systems and mobile app technologies to overcome this issue.Accordingly,this study proposes location-aware personalized traveler assistance(LAPTA),a system which integrates user preferences and the global positioning system(GPS)to generate personalized and location-aware recommendations.That integration will enable the enhanced recommendation of the developed scheme relative to those from the traditional recommender systems used in customer ratings.Specifically,LAPTA separates the data obtained from Google locations into name and category tags.After the data separation,the system fetches the keywords from the user’s input according to the user’s past research behavior.The proposed system uses the K-Nearest algorithm to match the name and category tags with the user’s input to generate personalized suggestions.The system also provides suggestions on the basis of nearby popular attractions using the Google point of interest feature to enhance system usability.The experimental results showed that LAPTA could provide more reliable and accurate recommendations compared to the reviewed recommendation applications.

Recommending Personalized POIs from Location Based Social Network

Location based social networks（ LBSNs） provide location specific data generated from smart phone into online social networks thus people can share their points of interest（ POIs）. POI collections are complex and can be influenced by various factors,such as user preferences,social relationships and geographical influence. Therefore,recommending new locations in LBSNs requires to take all these factors into consideration. However,one problem is how to determine optimal weights of influencing factors in an algorithm in which these factors are combined. The user similarity can be obtained from the user check-in data,or from the user friend information,or based on the different geographical influences on each user＇s check-in activities. In this paper,we propose an algorithm that calculates the user similarity based on check-in records and social relationships,using a proposed weighting function to adjust the weights of these two kinds of similarities based on the geographical distance between users. In addition,a non-parametric density estimation method is applied to predict the unique geographical influence on each user by getting the density probability plot of the distance between every pair of user＇s check-in locations. Experimental results,using foursquare datasets,have shown that comparisons between the proposed algorithm and the other five baseline recommendation algorithms in LBSNs demonstrate that our proposed algorithm is superior in accuracy and recall,furthermore solving the sparsity problem.

Benign Strategy for Recommended Location Service Based on Trajectory Data

A new collaborative filtered recommendation strategy oriented to trajectory data is proposed for communication bottlenecks and vulnerability in centralized system structure location services. In the strategy based on distributed system architecture, individual user information profiles were established using daily trajectory information and neighboring user groups were established using density measure. Then the trajectory similarity and profile similarity were calculated to recommend appropriate location services using collaborative filtering recommendation method. The strategy was verified on real position data set. The proposed strategy provides higher quality location services to ensure the privacy of user position information.

基于Location2vec的地点推荐算法

在地点推荐应用中,传统的协同过滤推荐算法由于签到数据稀疏导致推荐效果不佳。为提高推荐效果并克服传统协同过滤推荐算法受到热门地点影响的不足,提出一种新的地点推荐算法。将签到地点转换为向量,通过向量的余弦相似性计算签到地点的地点相似性。标记签到频次较低的地点为冷门地点,以计算签到地点的用户相似性,结合地理因素的影响,生成对用户的推荐列表。实验结果表明,相比传统协同过滤推荐算法,该算法 F 1值提升了0.009以上,推荐效果更好。

Exploiting Geo-Social Correlations to Improve Pairwise Ranking for Point-of-Interest Recommendation

Recently, as location-based social network(LBSN) rapidly grow, point-of-interest(POI) recommendation has become an important way to help people locate interesting places. Nowadays, there have been deep studies conducted on the geographical and social influence in the point-of-interest recommendation model based on the rating prediction. The fact is, however, relying solely on the rating fails to reflect the user's preferences very accurately, because the users are most concerned with the list of ranked point-of-interests(POIs) on the actual output of recommender systems. In this paper, we propose a co-pairwise ranking model called Geo-Social Bayesian Personalized Ranking model(GSBPR), which is based on the pairwise ranking with the exploiting geo-social correlations by incorporating the method of ranking learning into the process of POI recommendation. In this model, we develop a novel BPR pairwise ranking assumption by injecting users' geo-social preference. Based on this assumption, the POI recommendation model is reformulated by a three-level joint pairwise ranking model. And the experimental results based on real datasets show that the proposed method in this paper enjoys better recommendation performance compared to other state-of-the-art POI recommendation models.

An Entropy-Based Model for Recommendation of Taxis’Cruising Route

Cruising route recommendation based on trajectory mining can improve taxi-drivers'income and reduce energy consumption.However,existing methods mostly recommend pick-up points for taxis only.Moreover,their performance is not good enough since there lacks a good evaluation model for the pick-up points.Therefore,we propose an entropy-based model for recommendation of taxis'cruising route.Firstly,we select more positional attributes from historical pick-up points in order to obtain accurate spatial-temporal features.Secondly,the information entropy of spatial-temporal features is integrated in the evaluation model.Then it is applied for getting the next pick-up points and further recommending a series of successive points.These points are constructed a cruising route for taxi-drivers.Experimental results show that our method is able to obviously improve the recommendation accuracy of pick-up points,and help taxi-drivers make profitable benefits more than before.

基于位置相似性与Markov模型的移动轨迹预测算法

实时、准确的移动轨迹预测是移动端新兴业务发展的重要支撑。目前的移动轨迹预测大多采用Markov模型,但是Markov模型存在对历史轨迹信息利用不充分的问题。为此,论文提出了一种基于位置相似性与Markov模型的移动轨迹预测算法。首先,通过迭代网格划分方法实现原始轨迹数据的序列化;然后,根据用户当前轨迹位置找出历史轨迹集合中与之相似的历史轨迹;最后,由相似的历史轨迹建立转移概率矩阵,完成对用户未来区域的预测。在大规模数据集上的试验结果表明,相比于传统Markov模型,该方法的平均预测准确率提高了13.8%。

基于代价图的铁路线路走向通道智能规划方法

在铁路智能选线中,线路走向通道规划是一个至关重要的步骤,是后续线路方案设计的基础。针对分析总结现有线路走向通道规划方法的优缺点,提出基于代价图的铁路线路走向通道智能规划方法。基于线路技术标准进行地形快速探查,构建桥隧高代价面域;基于各类面域的边界特征线,通过三角剖分构建无向图,并形成代价图;基于差异演化算法,计算最优代价参数集;基于代价图,使用改进的Dijkstra算法生成多样化走向通道;基于走向通道,进行站位的智能推荐。应用验证结果表明,该方法能够快速生成多个线路走向通道,为线路方案决策提供参考,有效提高设计效率。

基于多源数据的城市医疗设施布局优化——以兰州市主城区为例

结合人口统计数据、POI数据、土地利用数据以及遥感影像数据,对公共医疗服务设施选址问题进行分析,提出通过熵权法综合空间可达性水平和随机森林选址推荐度计算空间区域选址推荐得分的计算方法。研究结果表明:兼顾设施供给能力、常住与流动人口医疗需求,兼顾资源分布与公共设施公平性,融合空间可达性和选址推荐度计算医疗设施推荐指数更能表现现有医疗资源的覆盖与缺失情况。最后以该方法分析兰州市主城区域内医疗资源配置合理性作为实证。该方法可为其他区域和其他类公共设施选址相关研究提供参考依据和理论基础。

基于LBS的旅游路线推荐系统设计

为满足日益增长的高品质、多样化、个性化旅游需求,采用基于位置的服务(Location Based Services,LBS),结合用户行为分析和智能算法处理,设计旅游路线推荐系统。该系统由个性化路线推荐模块、消息推送模块、用户管理模块、人工智能模块等构成。系统性能测试结果表明,该推荐系统能显著提高旅游规划效率和用户满意度,可为旅游行业智慧化服务模式发展提供技术支持。

基于极限学习机的兴趣点推荐模型

随着移动社交平台的发展,基于位置的社交网络服务(Location-Based Social Network,LBSN)已进入人们的视野。在LBSN中,根据用户的签到数据进行兴趣点(Point-of-Interest,POI)推荐是近年来研究的热点问题。提出一种基于极限学习机(Extreme Learning Machine,ELM)的POI推荐算法,提取用户的个人偏好、朋友偏好、类型偏好、流行度偏好等特征,利用ELM提供的分类方法,使用上述特征向量集合训练ELM分类器,最终根据分类结果向用户推荐POI。本文使用Foursquare和Twitter数据集的实验结果表明,该方法在精确率和效率方面均有所提高。

Next POI Recommendation Based on Location Interest Mining with Recurrent Neural Networks

In mobile social networks,next point-of-interest(POI)recommendation is a very important function that can provide personalized location-based services for mobile users.In this paper,we propose a recurrent neural network(RNN)-based next POI recommendation approach that considers both the location interests of similar users and contextual information(such as time,current location,and friends’preferences).We develop a spatial-temporal topic model to describe users’location interest,based on which we form comprehensive feature representations of user interests and contextual information.We propose a supervised RNN learning prediction model for next POI recommendation.Experiments based on real-world dataset verify the accuracy and efficiency of the proposed approach,and achieve best F1-score of 0.196754 on the Gowalla dataset and 0.354592 on the Brightkite dataset.

Time and Location Aware Points of Interest Recommendation inLocation-Based Social Networks

The wide spread of location-based social networks brings about a huge volume of user check-in data, whichfacilitates the recommendation of points of interest （POIs）. Recent advances on distributed representation shed light onlearning low dimensional dense vectors to alleviate the data sparsity problem. Current studies on representation learningfor POI recommendation embed both users and POIs in a common latent space, and users＇ preference is inferred basedon the distance/similarity between a user and a POI. Such an approach is not in accordance with the semantics of usersand POIs as they are inherently different objects. In this paper, we present a novel translation-based, time and locationaware （TransTL） representation, which models the spatial and temporal information as a relationship connecting users andPOIs. Our model generalizes the recent advances in knowledge graph embedding. The basic idea is that the embedding ofa 〈time, location〉 pair corresponds to a translation from embeddings of users to POIs. Since the POI embedding shouldbe close to the user embedding plus the relationship vector, the recommendation can be performed by selecting the top-kPOIs similar to the translated POI, which are all of the same type of objects. We conduct extensive experiments on tworeal-world data.sets. The results demonstrate that our TransTL model achieves the state-of-the-art performance. It is alsomuch more robust to data sparsity than the baselines.

结合用户特征的政务服务协同过滤推荐方法

为推荐政务服务相关事项,提高用户办事效率与政府服务水平,该文提出一种推荐算法,即结合用户特征的政务服务协同过滤推荐方法。该方法为解决传统协同过滤未考虑用户属性的问题,将用户画像技术与其相结合。首先,建立政务服务用户画像;然后,采用奇异值度量分析方法融合用户画像与基于用户的协同过滤算法,使特征属性参与相似度计算,改善用户之间的相似性,并解决数据稀疏性的问题,使推荐结果更具实际意义;最后,计算政务服务事项预测得分,将得分最高的TOP-N推荐给用户。在实验部分,该文利用某市企业法人的政务服务真实数据进行验证。结果显示,该算法能够满足政务服务推荐的个性化要求,预测准确性较高。

基于用户特征聚类与服务质量预测的推荐方法

随着服务系统中Web服务的不断增加,为用户进行个性化Web服务推荐成为服务计算领域最热门的研究课题之一,然而,服务推荐面临不可靠用户和服务导致推荐的不准确性问题.为了解决上述问题,提出一种基于位置和信誉感知的Web服务推荐方法.首先采用粒子群优化(Particle Swarm Optimization,PSO)对用户进行聚类,得到相似用户;其次,计算用户和服务的信誉来识别可信的用户和服务;最后,将相似用户和可信服务的信息整合到矩阵分解(Matrix Factorization,MF)中,为用户预测缺失的服务质量(Quality of Service,QoS).在真实数据集WS-Dream上的实验验证了提出方法的可行性与有效性.与其他先进的预测方法相比,该方法的MAE(Mean Absolute Error)和RMSE(Root Mean Squared Error)较低,证明该方法有较高的预测准确性.

基于用户长短期偏好的序列推荐模型

针对现有序列推荐模型忽略了不同用户的个性化行为,导致模型不能充分捕获用户动态偏好而产生的兴趣漂移等问题,提出了一种基于用户长短期偏好的序列推荐模型(Sequential Recommendation Model Based on User’s Long and Short Term Preference,ULSP-SRM)。首先,根据用户的序列中交互物品的类别和时间信息生成用户的动态类别嵌入,进而有效建立物品之间的关联性,并且降低数据的稀疏性;其次,根据用户当前点击物品和最后一项点击的时间间隔信息生成个性化时序位置嵌入矩阵,模拟用户的个性化聚集现象,以更好地反映用户偏好的动态变化;然后,将融合了个性化时序位置嵌入矩阵的用户长期偏好序列以会话为单位输入门控循环单元中,生成用户的长期偏好表示,并通过注意力机制将用户长短期偏好进行融合,生成用户的最终偏好表示,从而达到充分捕获用户偏好的目的;最后,将用户最终偏好表示输入推荐预测层进行下一项推荐预测。在Amazon公开数据集的7个子集上进行实验,采用AUC(Area Under Curve)值、召回率和精确率指标进行综合评估,实验结果表明,所提模型的表现优于其他先进基准模型,有效地提升了推荐性能。