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2022 ◽  
Vol 34 (3) ◽  
pp. 1-21
Xue Yu

The purpose is to solve the problems of sparse data information, low recommendation precision and recall rate and cold start of the current tourism personalized recommendation system. First, a context based personalized recommendation model (CPRM) is established by using the labeled-LDA (Labeled Latent Dirichlet Allocation) algorithm. The precision and recall of interest point recommendation are improved by mining the context information in unstructured text. Then, the interest point recommendation framework based on convolutional neural network (IPRC) is established. The semantic and emotional information in the comment text is extracted to identify user preferences, and the score of interest points in the target location is predicted combined with the influence factors of geographical location. Finally, real datasets are adopted to evaluate the recommendation precision and recall of the above two models and their performance of solving the cold start problem.

During the recent years, there is an increasing demand for software systems that dynamically adapt their behavior at run-time in response to changes in user preferences, execution environment, and system requirements, being thus context-aware. Authors are referring here to requirements related to both functional and non-functional aspects of system behavior since changes can also be induced by failures or unavailability of parts of the software system itself. To ensure the coherence and correctness of the proposed model, all relevant properties of system entities are precisely and formally described. This is especially true for non-functional properties, such as performance, availability, and security. This article discusses semantic concepts for the specification of non-functional requirements, taking into account the specific needs of a context-aware system. Based on these semantic concepts, we present a specification language that integrates non-functional requirements design and validation in the development process of context-aware self-adaptive systems.

2022 ◽  
Vol 40 (4) ◽  
pp. 1-40
Weiyu Ji ◽  
Xiangwu Meng ◽  
Yujie Zhang

POI recommendation has become an essential means to help people discover attractive places. Intuitively, activities have an important impact on users’ decision-making, because users select POIs to attend corresponding activities. However, many existing studies ignore the social motivation of user behaviors and regard all check-ins as influenced only by individual user interests. As a result, they cannot model user preferences accurately, which degrades recommendation effectiveness. In this article, from the perspective of activities, this study proposes a probabilistic generative model called STARec. Specifically, based on the social effect of activities, STARec defines users’ social preferences as distinct from their individual interests and combines these with individual user activity interests to effectively depict user preferences. Moreover, the inconsistency between users’ social preferences and their decisions is modeled. An activity frequency feature is introduced to acquire accurate user social preferences because of close correlation between these and the key impact factor of corresponding check-ins. An alias sampling-based training method was used to accelerate training. Extensive experiments were conducted on two real-world datasets. Experimental results demonstrated that the proposed STARec model achieves superior performance in terms of high recommendation accuracy, robustness to data sparsity, effectiveness in handling cold-start problems, efficiency, and interpretability.

2022 ◽  
Vol 40 (2) ◽  
pp. 1-23
Zhiqiang Tian ◽  
Yezheng Liu ◽  
Jianshan Sun ◽  
Yuanchun Jiang ◽  
Mingyue Zhu

Personalized recommendation has become more and more important for users to quickly find relevant items. The key issue of the recommender system is how to model user preferences. Previous work mostly employed user historical data to learn users’ preferences, but faced with the data sparsity problem. The prevalence of online social networks promotes increasing online discussion groups, and users in the same group often have similar interests and preferences. Therefore, it is necessary to integrate group information for personalized recommendation. The existing work on group-information-enhanced recommender systems mainly relies on the item information related to the group, which is not expressive enough to capture the complicated preference dependency relationships between group users and the target user. In this article, we solve the problem with the graph neural networks. Specifically, the relationship between users and items, the item preferences of groups, and the groups that users participate in are constructed as bipartite graphs, respectively, and the user preferences for items are learned end to end through the graph neural network. The experimental results on the and Douban Movie datasets show that considering group preferences can improve the recommendation performance and demonstrate the superiority on sparse users compared

2022 ◽  
Vol 40 (2) ◽  
pp. 1-29
Jun Yang ◽  
Weizhi Ma ◽  
Min Zhang ◽  
Xin Zhou ◽  
Yiqun Liu ◽  

Recommendation in legal scenario (Legal-Rec) is a specialized recommendation task that aims to provide potential helpful legal documents for users. While there are mainly three differences compared with traditional recommendation: (1) Both the structural connections and textual contents of legal information are important in the Legal-Rec scenario, which means feature fusion is very important here. (2) Legal-Rec users prefer the newest legal cases (the latest legal interpretation and legal practice), which leads to a severe new-item problem. (3) Different from users in other scenarios, most Legal-Rec users are expert and domain-related users. They often concentrate on several topics and have more stable information needs. So it is important to accurately model user interests here. To the best of our knowledge, existing recommendation work cannot handle these challenges simultaneously. To address these challenges, we propose a legal information enhanced graph neural network–based recommendation framework (LegalGNN). First, a unified legal content and structure representation model is designed for feature fusion, where the Heterogeneous Legal Information Network (HLIN) is constructed to connect the structural features (e.g., knowledge graph) and contextual features (e.g., the content of legal documents) for training. Second, to model user interests, we incorporate the queries users issued in legal systems into the HLIN and link them with both retrieved documents and inquired users. This extra information is not only helpful for estimating user preferences, but also valuable for cold users/items (with less interaction history) in this scenario. Third, a graph neural network with relational attention mechanism is applied to make use of high-order connections in HLIN for Legal-Rec. Experimental results on a real-world legal dataset verify that LegalGNN outperforms several state-of-the-art methods significantly. As far as we know, LegalGNN is the first graph neural model for legal recommendation.

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 208
Jun Wu ◽  
Yuanyuan Li ◽  
Li Shi ◽  
Liping Yang ◽  
Xiaxia Niu ◽  

Existing studies have made a great endeavor in predicting users’ potential interests in items by modeling user preferences and item characteristics. As an important indicator of users’ satisfaction and loyalty, repeat purchase behavior is a promising perspective to extract insightful information for community e-commerce. However, the repeated purchase behaviors of users have not yet been thoroughly studied. To fill in this research gap from the perspective of repeated purchase behavior and improve the process of generation of candidate recommended items this research proposed a novel approach called ReRec (Repeat purchase Recommender) for real-life applications. Specifically, the proposed ReRec approach comprises two components: the first is to model the repeat purchase behaviors of different types of users and the second is to recommend items to users based on their repeat purchase behaviors of different types. The extensive experiments are conducted on a real dataset collected from a community e-commerce platform, and the performance of our model has improved at least about 13.6% compared with the state-of-the-art techniques in recommending online items (measured by F-measure). Specifically, for active users, with w = 1 and N(UA)∈[5,25], the results of ReRec show a significant improvement (at least 50%) in recommendation. With α and σ as 0.75 and 0.2284, respectively, the proposed ReRec for unactive users is also superior to (at least 13.6%) the evaluation indicators of traditional Item CF when N(UB)∈[6, 25]. To the best of our knowledge, this paper is the first to study recommendations in community e-commerce.

2022 ◽  
Vol 5 ◽  
Agnes Gachuiri ◽  
Ana Maria Paez-Valencia ◽  
Marlène Elias ◽  
Sammy Carsan ◽  
Stepha McMullin

Food trees contribute substantially to the food and nutrition security of millions of rural households in Africa. Farming communities prioritize tree and shrub species on farms based on a combination of factors, including their knowledge of potential uses the species' economic potential and a range of constraints and opportunities that each farmer faces depending on their position within the community and the household, in cultivating, harvesting and processing tree products. Gender and age are strong determinants of such constraints and opportunities as well as ecological knowledge and use of tree resources. This study contributes to the understanding of gender and generational preferences for food tree species that determine their use, and which contribute to food and nutrition security in Central Uganda and Eastern Kenya. Sixteen gender and age segregated focus group discussions were conducted to assess food tree species preferences. A total of 61 food tree species were listed −46 in Uganda (including 16 indigenous species) and 44 in Kenya (21 indigenous species). Results showed knowledge on food tree species differed by gender and age, with differences across gender lines found more prevalently in Uganda, and across generational lines in Kenya. Age-related differences in knowledge and preferences were clear with regard to indigenous species, whereby older women and men were found to have the most knowledge in both countries. Among key challenges for food tree cultivation, farming households mentioned knowledge of tree management, the lack of planting materials, especially for improved varieties, prolonged droughts and scarcity of land. Some of these constraints were gendered and generational, with women mostly mentioning lack of knowledge about planting and management as well as cultural restrictions, such as only having access to land when married; whereas younger men indicated management challenges such as pests, limited markets, as well as scarcity and limited ownership of land. Overall findings suggest that consulting user preferences for food tree species and constraints experienced by gender and age group could be important in the design of interventions which involve a diversity of food trees.

Linus W. Dietz ◽  
Sameera Thimbiri Palage ◽  
Wolfgang Wörndl

AbstractConversational recommender systems have been introduced to provide users the opportunity to give feedback on items in a turn-based dialog until a final recommendation is accepted. Tourism is a complex domain for recommender systems because of high cost of recommending a wrong item and often relatively few ratings to learn user preferences. In a scenario such as recommending a city to visit, conversational content-based recommendation may be advantageous, since users often struggle to specify their preferences without concrete examples. However, critiquing item features comes with challenges. Users might request item characteristics during recommendation that do not exist in reality, for example demanding very high item quality for a very low price. To tackle this problem, we present a novel conversational user interface which focuses on revealing the trade-offs of choosing one item over another. The recommendations are driven by a utility function that assesses the user’s preference toward item features while learning the importance of the features to the user. This enables the system to guide the recommendation through the search space faster and accurately over prolonged interaction. We evaluated the system in an online study with 600 participants and find that our proposed paradigm leads to improved perceived accuracy and fewer conversational cycles compared to unit critiquing.

2022 ◽  
Vol 306 ◽  
pp. 118004
Michel Zade ◽  
Sebastian Dirk Lumpp ◽  
Peter Tzscheutschler ◽  
Ulrich Wagner

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