A Novel IoT Application Recommendation System Using Metaheuristic Multi-Criteria Analysis

There are a variety of Internet of Things(IoT)applications that cover different aspects of daily life.Each of these applications has different criteria and sub-criteria,making it difficult for the user to choose.This requires an automated approach to select IoT applications by considering criteria.This paper presents a novel recommendation system for presenting applications on the IoT.First,using the analytic hierarchy process(AHP),a multi-layer architecture of the criteria and sub-criteria in IoT applications is presented.This architecture is used to evaluate and rank IoT applications.As a result,finding the weight of the criteria and subcriteria requires a metaheuristic approach.In this paper,a sequential quadratic programming algorithm is used to find the optimal weight of the criteria and sub-criteria automatically.To the best of our knowledge,this is the first study to use an analysis of metaheuristic criteria and sub-criteria to design an IoT application recommendation system.The evaluations and comparisons in the experimental results section show that the proposed method is a comprehensive and reliable model for the construction of an IoT applications recommendation system.

A general tail item representation enhancement framework for sequential recommendation

Recently advancements in deep learning models have significantly facilitated the development of sequential recommender systems(SRS).However,the current deep model structures are limited in their ability to learn high-quality embeddings with insufficient data.Meanwhile,highly skewed long-tail distribution is very common in recommender systems.Therefore,in this paper,we focus on enhancing the representation of tail items to improve sequential recommendation performance.Through empirical studies on benchmarks,we surprisingly observe that both the ranking performance and training procedure are greatly hindered by the poorly optimized tail item embeddings.To address this issue,we propose a sequential recommendation framework named TailRec that enables contextual information of tail item well-leveraged and greatly improves its corresponding representation.Given the characteristics of the sequential recommendation task,the surrounding interaction records of each tail item are regarded as contextual information without leveraging any additional side information.This approach allows for the mining of contextual information from cross-sequence behaviors to boost the performance of sequential recommendations.Such a light contextual filtering component is plug-and-play for a series of SRS models.To verify the effectiveness of the proposed TailRec,we conduct extensive experiments over several popular benchmark recommenders.The experimental results demonstrate that TailRec can greatly improve the recommendation results and speed up the training process.The codes of our methods have been available.

KGSR-GG:A Noval Scheme for Dynamic Recommendation

Recommendation algorithms regard user-item interaction as a sequence to capture the user’s short-term preferences,but conventional algorithms cannot capture information of constantly-changing user interest in complex contexts.In these years,combining the knowledge graphwith sequential recommendation has gained momentum.The advantages of knowledge graph-based recommendation systems are that more semantic associations can improve the accuracy of recommendations,rich association facts can increase the diversity of recommendations,and complex relational paths can hence the interpretability of recommendations.But the information in the knowledge graph,such as entities and relations,often fails to be fully utilized and high-order connectivity is unattainable in graph modelling in knowledge graph-based sequential recommender systems.To address the above problems,a knowledge graph-based sequential recommendation algorithm that combines the gated recurrent unit and the graph neural network(KGSRGG)is proposed in the present work.Specifically,entity disambiguation in the knowledge graph is performed on the preprocessing layer;on the embedding layer,the TransR embedding technique is employed to process the user information,item information and the entities and relations in the knowledge graph;on the aggregation layer,the information is aggregated by graph convolutional neural networks and residual connections;and at last,on the sequence layer,a bi-directional gated recurrent unit(Bi-GRU)is utilized to model the user’s sequential preferences.The research results showed that this newalgorithm performed better than existing sequential recommendation algorithms on the MovieLens-1M and Book-Crossing datasets,as measured by five evaluation indicators.

序列标签推荐

随着互联网技术的发展以及社交网络的扩大,网络平台已经成为人们获取信息的一个重要途径。标签的引入提升了信息分类及检索效率。同时,标签推荐系统的出现不仅方便了用户输入标签,还提高了标签的质量。传统的标签推荐算法通常只考虑标签和项目两个主体,而忽略了用户在选择标签时个人意图所起到的重要作用。由于在标签推荐系统中标签最终由用户确定,因此用户的偏好在标签推荐中起着关键作用。为此,引入用户作为主体,并结合用户发布的历史帖子的先后顺序,将标签推荐任务建模为更加符合真实场景的序列标签推荐任务。提出了一种基于MLP的序列标签推荐方法(MLP for Sequential Tag Recommendation, MLP4STR),该方法显式地建模用户偏好用于引导整体标签推荐。MLP4STR采用一种跨特征对齐的MLP序列特征提取框架,将文本和标签的特征对齐,获取用户的历史帖子信息和历史标签信息中隐含的用户动态兴趣。最后,结合帖子内容和用户偏好进行标签推荐。在4个真实世界的数据集上得到的实验结果表明,MLP4STR能够有效地学习序列标签推荐中的用户历史行为序列的信息,其中,评价指标F1@5较最优的对比算法有显著提升。

Sequential Recommendation via Cross-Domain Novelty Seeking Trait Mining

Transfer learning has attracted a large amount of interest and research in last decades, and some effort has been made to build more precise recommendation systems. Most previous transfer recommendation systems assume that the target domain shares the same/similar rating patterns with the auxiliary source domain, which is used to improve the recommendation performance. However, almost all existing transfer learning work does not consider the characteristics of sequential data. In this paper, we study the new cross-domain recommendation scenario by mining novelty-seeking trait. Recent studies in psychology suggest that novelty-seeking trait is highly related to consumer behavior, which has a profound business impact on online recommendation. Previous work performed on only one single target domain may not fully characterize users' novelty-seeking trait well due to the data scarcity and sparsity, leading to the poor recommendation performance. Along this line, we propose a new cross-domain novelty-seeking trait mining model (CDNST for short) to improve the sequential recommendation performance by transferring the knowledge from auxiliary source domain. We conduct systematic experiments on three domain datasets crawled from Douban to demonstrate the effectiveness of our proposed model. Moreover, we analyze the directed influence of the temporal property at the source and target domains in detail.

TransRec++:Translation-based sequential recommendation with heterogeneous feedback

1 Introduction Nowadays,recommender systems are widely used because of the information overload problem on the Internet.There are a variety of feedback in recommender systems,such as explicit feedback,implicit feedback,sequential feedback,etc.Among them,modeling of heterogeneous sequential feedback,which contains not only different types of feedback such as examinations and purchases but also the sequential information,is an emerging and important problem receiving more and more attention.Heterogeneous sequential feedback is relatively easy to be collected in a deployed system and is also able to provide more information than the homogeneous feedback,which is thus expected to be helpful in improving the recommendation accuracy.

Quantifying predictability of sequential recommendation via logical constraints

The sequential recommendation is a compelling technology for predicting users’next interaction via their historical behaviors.Prior studies have proposed various methods to optimize the recommendation accuracy on different datasets but have not yet explored the intrinsic predictability of sequential recommendation.To this end,we consider applying the popular predictability theory of human movement behavior to this recommendation context.Still,it would incur serious bias in the next moment measurement of the candidate set size,resulting in inaccurate predictability.Therefore,determining the size of the candidate set is the key to quantifying the predictability of sequential recommendations.Here,different from the traditional approach that utilizes topological constraints,we first propose a method to learn inter-item associations from historical behaviors to restrict the size via logical constraints.Then,we extend it by 10 excellent recommendation algorithms to learn deeper associations between user behavior.Our two methods show significant improvement over existing methods in scenarios that deal with few repeated behaviors and large sets of behaviors.Finally,a prediction rate between 64%and 80%has been obtained by testing on five classical datasets in three domains of the recommender system.This provides a guideline to optimize the recommendation algorithm for a given dataset.

Deep Sequential Model for Anchor Recommendation on Live Streaming Platforms

Live streaming has grown rapidly in recent years, attracting increasingly more participation. As the number of online anchors is large, it is difficult for viewers to find the anchors they are interested in. Therefore, a personalized recommendation system is important for live streaming platforms. On live streaming platforms, the viewer’s and anchor’s preferences are dynamically changing over time. How to capture the user’s preference change is extensively studied in the literature, but how to model the viewer’s and anchor’s preference changes and how to learn their representations based on their preference matching are less studied. Taking these issues into consideration, in this paper, we propose a deep sequential model for live streaming recommendation. We develop a component named the multi-head related-unit in the model to capture the preference matching between anchor and viewer and extract related features for their representations. To evaluate the performance of our proposed model, we conduct experiments on real datasets, and the results show that our proposed model outperforms state-of-the-art recommendation models.

Multimodal Interactive Network for Sequential Recommendation

Building an effective sequential recommendation system is still a challenging task due to limited interactions among users and items.Recent work has shown the effectiveness of incorporating textual or visual information into sequential recommendation to alleviate the data sparse problem.The data sparse problem now is attracting a lot of attention in both industry and academic community.However,considering interactions among modalities on a sequential scenario is an interesting yet challenging task because of multimodal heterogeneity.In this paper,we introduce a novel recommendation approach of considering both textual and visual information,namely Multimodal Interactive Network(MIN).The advantage of MIN lies in designing a learning framework to leverage the interactions among modalities from both the item level and the sequence level for building an efficient system.Firstly,an item-wise interactive layer based on the encoder-decoder mechanism is utilized to model the item-level interactions among modalities to select the informative information.Secondly,a sequence interactive layer based on the attention strategy is designed to capture the sequence-level preference of each modality.MIN seamlessly incorporates interactions among modalities from both the item level and the sequence level for sequential recommendation.It is the first time that interactions in each modality have been explicitly discussed and utilized in sequential recommenders.Experimental results on four real-world datasets show that our approach can significantly outperform all the baselines in sequential recommendation task.

基于情境感知和序列模式挖掘的气象学习资源推荐算法

随着互联网的快速发展,气象部门职工作为学习者可以获得的学习资源得到极大丰富。信息超载导致检索合适的在线学习资源时遇到了困难;学习者在不同学习环境和序列访问模式上也有不同的学习需求。但是,现有的推荐系统,如基于内容的推荐和协同过滤,没有结合学习者的情境和序列访问模式,推荐结果准确度不高。本文提出了一种结合情境感知、序列模式挖掘和协同过滤算法的混合推荐算法来为学习者推荐学习资源。混合推荐算法中,情境感知被用来整合学习者的情境信息,如知识水平和学习目标;序列模式挖掘被用来对网络日志进行挖掘,发现学习者的序列访问模式;协同过滤被用来根据学习者的情境数据和序列访问模式为目标学习者计算预测并生成建议。实验和应用效果表明,该混合推荐算法推荐的质量和准确性方面优于其他推荐算法。

融合时间和知识信息的生成对抗网络序列推荐算法

序列推荐作为一种常用的推荐系统技术,通过对用户的历史交互序列进行建模来预测下一个可能交互的项目。现有的序列推荐方法主要利用用户交互序列和上下文信息进行推荐,忽略了序列中交互项目之间的时间间隔信息,交互项目之间的组合依赖以及上下文信息中存在噪声的问题,导致推荐结果受限。针对以上问题,提出一种基于生成对抗网络的序列推荐模型TKWGAN,该模型包含一个生成器和一个判别器。生成器结合了用户历史交互序列和各项目之间的时间间隔信息对用户偏好进行建模并生成预测,判别器则引入了知识图谱信息对项目进行语义扩充,从而能更准确地对生成器的预测进行合理性判断。针对用户交互序列和知识图谱信息中可能存在噪声的问题,提出一种基于小波变换的多核卷积神经网络来构造判别器,以更全面、准确地捕获用户的潜在兴趣,提高推荐的准确性。在MovieLens-1M、Amazon Books和Yelp2018这3个公开数据集上的实验结果表明,与8个序列化推荐算法相比,提出的TKWGAN模型在命中率(HR@N)和归一化折损累计增益(NDCG@N)指标上均有显著提升。

基于层级过滤器和时间卷积增强自注意力网络的序列推荐

针对实际推荐场景中用户意外交互产生的噪声问题,以及自注意力机制中注意力分布分散导致用户短期需求偏移难以捕获的问题,提出一种基于层级过滤器和时间卷积增强自注意力网络的序列推荐(FTARec)模型。首先,通过层级过滤器过滤原始数据中的噪声;其次,结合时间卷积增强自注意力网络和解耦混合位置编码获取用户嵌入,该过程通过时间卷积增强补充自注意力网络在项目短期依赖建模上的不足;最后,结合对比学习改善用户嵌入,并根据最终用户嵌入进行预测。相较于自注意力序列推荐(SASRec)、过滤增强的多层感知器序列推荐方法(FMLPRec)等现有序列推荐模型,FTARec在3个公开数据集Beauty、Clothing和Sports上取得了更高的命中率(HR)和归一化折损累计增益(NDCG),相较于次优的DuoRec,HR@10分别提高了7.91%、13.27%和12.84%,NDCG@10分别提高了5.52%、8.33%和9.88%,验证了所提模型的有效性。

解释引导增强的多对对比学习序列推荐

序列推荐中对比学习可有效地缓解数据稀疏性问题,但现有对比学习采用的随机增强方法产生的正样本表现出假阳性,单对对比学习不能很好地中和假阴性的负样本问题,导致推荐性能受限。针对上述问题,提出解释引导增强的多对对比学习序列推荐算法(EMC4Rec)。首先利用解释方法来确定用户序列中项目的重要性分数,再通过解释引导增强根据项目的重要性分数生成多个高质量的正样本并执行多对对比学习。在Beauty、Toys、ML-1M三个公共数据集上实验结果表明,EMC4Rec在命中率(HR)和归一化折损累计增益(NDCG)两个指标上相较于CL4SRec、CoSeRec分别提升8.13%,11.38%。

基于傅里叶变换与近端采样的序列推荐算法

传统推荐算法比较注重于模型本身对于推荐效果的提升,实际上数据质量对于算法的影响更为重要,但目前在推荐算法领域对于数据的科学处理方法比较零散,没有形成一个系统的框架。针对以上问题,基于傅里叶变换与近端序列采样的数据预处理,结合SASRec提出可以普遍应用的序列推荐框架FTRRec。首先通过傅里叶变换将序列数据在时域和频域中相互转换,并根据序列数据的特点,过滤序列中的无用信息,其次使用近端序列采样替换传统的滑动窗口采样法,加速样本采样的同时,提升模型对于序列的特征捕获能力。通过在5个公开数据集上的实验,将框架应用于三个不同的主流推荐算法时,每种模型均有3%-5%的提升。

基于排序蒸馏的序列化推荐算法

为解决当前基于知识蒸馏的推荐算法排名有效性和效率低,以及现有知识蒸馏模型更强调的是静态和单一知识迁移的问题,提出一种基于排序蒸馏的序列化推荐算法。训练一个性能优越、规模大的教师模型,训练一个符合移动终端设备的小模型即学生模型,使学生模型在教师模型的指导下学习排序。学生模型实现了与教师模型相似的排名性能,且学生模型规模较小提高了在线推荐效率。通过在数据集MovieLens和Gowalla上的实验,验证了该模型增强了学生模型的学习效果,缓解了学生模型学习不充分导致排名不佳的问题。模型可以自然地运用于序列化推荐的模型中,具有很好的通用性。

基于知识增强对比学习的长尾用户序列推荐算法

序列推荐根据目标用户的历史交互序列,预测其可能感兴趣的下一个物品。现有的序列推荐方法虽然可以有效捕获用户的历史交互序列中的长期依赖关系,但是无法为交互序列较短且用户数量庞大的长尾用户提供精确推荐。为了解决此问题,提出了一种基于知识增强对比学习的长尾用户序列推荐算法。首先,基于知识图谱中的丰富实体关系信息,构建一个基于语义的物品相似度度量,分别提取原始序列中物品的协同关联物品。然后,基于不同学习序列提出2种序列增强算子,通过增强自监督信号解决长尾用户序列训练数据不足的问题。最后,通过对比自监督任务和推荐主任务的网络参数共享的联合训练,为长尾用户提供更精确的序列推荐结果。在实际数据集上的实验结果表明,所提算法可以有效提高针对长尾用户的序列推荐精度。

采用偏好编辑的轻量自注意降噪序列推荐模型

在自注意序列推荐中,除项目嵌入矩阵带来巨大内存消耗问题和自注意层中的不相关信息带来噪声问题,还存在如何在用户行为数据稀疏的情况下准确提取和表示用户偏好的关键问题。针对这些问题,提出一种采用偏好编辑的轻量自注意降噪序列推荐模型(LDSR-PE)。采用上下文感知的动态嵌入组合方案缓解内存消耗问题,在每个自注意层上附加可训练的二进制掩膜,实现自适应修剪不相关噪声项。为更好训练模型,设计基于偏好编辑的自监督学习策略,促使序列推荐模型在不同的交互序列之间区分公共和唯一的偏好。在3个公开数据集上的实验结果表明,LDSR-PE优于主流先进推荐模型。

基于平滑图掩码编码器的顺序推荐模型

针对现有顺序推荐模型在处理推荐任务时由于数据集标签稀缺和用户交互数据噪声导致性能降低的问题,提出基于平滑图掩码编码器的顺序推荐模型(Smoothing Graph Masked Encoder Recommender System,SGMERec).首先,设计数据平滑编码器处理数据,提升数据质量,降低极端值和数据噪声的负面影响.然后,设计图掩码编码器,自适应提取全局项目的转换信息,构造关系图帮助模型补全缺失的标签数据,提高模型对于标签稀缺问题的应对能力.最后,运用批标准化,归一化每个神经网络层的输入分布,确保每层输入的分布相对稳定,降低用户序列的稀缺标签比例.在3个真实数据集上的实验表明,SGMERec具有一定的性能提升.

融合时间感知和多兴趣提取网络的序列推荐

针对序列推荐任务中的时间动态性和多重兴趣建模问题,提出一种时间感知的项目嵌入方法,用于学习项目之间的时间关联性。在此基础上,提出一种融合时间感知和多兴趣提取网络的序列推荐(time-aware multi-interest sequence recommendation,TMISA)方法。TMISA采用自注意力序列推荐模型作为局部特征学习模块,以捕捉用户行为序列中的动态偏好;通过多兴趣提取网络对用户的全局偏好进行建模;引入门控聚合模块将局部和全局特征表示动态融合,生成最终的用户偏好表示。实验证明,在5个真实推荐数据集上,TMISA模型表现出卓越性能,超越了多个先进的基线模型。

融合局部最优划分长短期兴趣的序列推荐

序列推荐中划分用户的长期和短期兴趣非常重要。现有的序列推荐模型多简单预设短期兴趣长度,但性能提升不明显。为了更好地建模用户长短期兴趣,本文提出了一种融合局部最优划分长短期兴趣的序列推荐模型,采用了一种局部最优短期兴趣长度算法,自动和自适应搜索最优短期兴趣长度,并设计了MLP层分别对长短期兴趣建模。在三个数据集上进行实验,结果表明运用该模型能够取得与最先进模型具有竞争力的性能。