International Journal of Human–Computer Interaction ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/hihc20 An Improved Human-Computer Interaction Content Recommendation Method Based on Knowledge Graph Zhu He To cite this article: Zhu He (22 Dec 2023): An Improved Human-Computer Interaction Content Recommendation Method Based on Knowledge Graph, International Journal of Human–Computer Interaction, DOI: 10.1080/10447318.2023.2295734 To link to this article: https://doi.org/10.1080/10447318.2023.2295734 Published online: 22 Dec 2023. Submit your article to this journal Article views: 34 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=hihc20 INTERNATIONAL JOURNAL OF HUMAN–COMPUTER INTERACTION https://doi.org/10.1080/10447318.2023.2295734 An Improved Human-Computer Interaction Content Recommendation Method Based on Knowledge Graph Zhu He Global Business School, UCSI University, Kuala Lumpur, Malaysia ABSTRACT KEYWORDS Since human-to-human communication is contentful and coherent, during human-computer inter­ action (HCI), people naturally hope that the computer’s reply will be contentful and coherent. How to enable computers to recognize, understand and generate quality content and coherent responses like humanshas drawn a great deal of interest from bothindustry and academia.In order to address the current problems of lack of background knowledge of robots and low consistency of responses in open-domain HCI systems, we present a content recommendation method on the basis of knowledge graph ripple network. In order to realize a human-computer interaction system with better content and stronger coherence, and this model simulates the real process of humanhuman communication. At first, the emotional friendliness of HCI is gotten through calculating the emotional confidence level together with emotional evaluation value of HCI. After that, the exter­ nal knowledge graph is introduced as the robot’s background knowledge, and the dialog entities are embedded in the ripple network of knowledge graphsto access the content of entities that may be of interest to participants. Lastly, the robot reply is given by comprehensively considering the content and emotional friendliness. The results of the experiments indicate a comparison with comparative modeling approaches like MECs models, robots with emotional measures and back­ ground knowledge can effectively enhance their emotional consistency and friendliness when per­ forming HCI. Human-computer inter­ action; knowledge graph; ripple network; deep learning 1. Introduction The evolution of wireless communication technologies and the spread of social networks have driven transformations in the field of human-computer interaction (HCI). Every change in HCI will set off a huge wave of changes in the information industry. Changes in the information industry in turn promote the development of the communications industry. Human-computer interaction technology is com­ mitted to smooth and natural communication between humans and computers, aiming to dissolve the boundaries of dialogue between interactive systems and achieve smooth and natural information exchange between humans and machines. Specifically, it ranges from the initial command line human-computer interaction to traditional graphical interface interaction, and then to various voice control interactions (Shackel, 1997). Nowadays, the innovation of interactive interface aesthetics no longer meets people’s needs. During the interaction process, participants hope to take into account more convenient and more customary aes­ thetic interaction methods (Ren et al., 2023). In the era of mobile Internet, human-computer interaction is gradually changing from computers passively accepting, processing, and replying to information to actively understanding, proc­ essing, and replying to information, further improving the user’s interactive experience. CONTACT Zhu He julylitbri@outlook.com � 2023 Taylor & Francis Group, LLC With the emergence and popularization of various human-computer interaction systems, the relationship between humans and machines, data, and information has been broken. Human-computer interaction is developing in the direction of natural human conversation and towards a more intelligent and natural human-computer interaction. interactive development. Conventional passive interaction logic is very simple. The user gives instructions to the machine, the machine executes them and gives the results back to the user. While the entire process is straightforward and efficient, it is not natural or intelligent. Real intelligence and nature should be when the machine actively provides natural and intelligent services to users through perception and prediction. Human-computer interaction systems are also developing from passively accepting user information to actively understanding user intentions. This change in inter­ action methods will enable machines to more naturally and accurately understand user intentions or emotions to pro­ vide services for users. Such a change requires intelligent robots to have stronger emotional perception and intelligent understanding capabilities. In order to achieve such a goal, more and more academics and industrial people have launched many researches including robot cognitive and emotional computing (Zhou and Wang, 2017), robot per­ sonalization (Irfan et al., 2019), robot anthropomorphism Global Business School, UCSI University, Kuala Lumpur, Malaysia 2 Z. HE (Spatola et al., 2019), robot intelligent dialogue (Jokinen, 2018), etc. The study of knowledge graph-based content recommen­ dation techniques for HCI is the focus of this article. Our suggested model technique replicates the true human-tohuman communication process in an open domain inter­ active system. Initially, the robot’s background knowledge is considered to be represented by the knowledge graph. Second, during human-to-human contact, the ripple net­ work is employed to imitate the waking of locally relevant background information. This article is focused on know­ ledge graph-based HCI content recommendation, which offers helpful investigation for implementing a more natural and intelligent HCI system in both closed and open domains. 2. Related work Letting robots have similar capabilities to human brains is the eventual goal of HCI, and it is a long and arduous chal­ lenging task. Since 1951, academia and industry have widely adopted the ideas proposed by Turing in “Computers and Intelligence” and used human-machine dialogue to test the intelligence level of robots. Usually, humans perceive the intelligence or emotional intelligence level of a robot through the content of its reply during human-computer interaction. Human-computer interaction systems are div­ ided into task-driven closed-and open-domain dialogue sys­ tems without specific tasks. In the industrial world, the next generation of human-computer interaction mainly takes the form of dialogue systems, and many technology companies have invested in research and development work and have also developed some products with commercial value (Adamopoulou and Moussiades, 2020; Hoy, 2018). We ana­ lyze the current research status of content recommendation by robots in open domain and closed domain interactive systems respectively. 2.1. Research status of robot content recommendation in open domain The human-computer interaction system under the open domain has the following two distinctive characteristics. First, participants can input any content of interest, and there are no clear reply rules for the robot’s replies. The reply content only needs to take into account the partici­ pants’ emotions and the relevance of the content. Second, the robot, which plays the role of companion in the humancomputer interaction process, does not have background knowledge, and its replies are not very relevant. Many researchers have conducted various studies on robot content recommendation under human-computer interaction sys­ tems in the open domain. In the literature (Liu et al., 2017), the author argued that participants’ expression changes gen­ erate external emotional stimuli for the robot and presented a successive cognitive emotion regulation model that can endow the robot with certain emotional cognitive capabil­ ities. For realizing the intelligent emotional expression, Rodr�ıguez et al. (2016) presented an emotion generation frame that allows robots to generate the same emotional state as the participants, which can build emotional trust between both parties in the interaction during the dialog. Jokinen and Wilcock (2013) maps real-life realistic emo­ tional states into the PAD 3D space, where the value of each dimension on the 3D axes is given by a psychological attri­ bute. The emotional space model of PAD is applied to express the various successive emotional states of a robot. To fulfill the emotional demands of participants during HCI, robots are gradually realizing the emotional intelli­ gence ability of “sorrowing you when you are sad, and happy when you are happy”. The authors proposed an Emotional Chatting Machine (ECM) in the literature (Zhou et al., 2018). They quantified unique human emotions and introduced them into the generative dialogue system so that the robot can not only extract emotions from the partici­ pants’ dialogue content but also make empathetic responses from an emotionally consistent direction. The purpose of its research is to enable robotic responses to participants’ emo­ tions. Adamopoulou and Moussiades (2020) made a sequence-to-sequence improvement for emotional issues in dialogue. First, three-dimensional word vectors with emo­ tional information are introduced. Second, for better results, the emotional dissonance loss function is minimized and the emotional content is maximized. Finally, emotional factors are comprehensively considered to allow the decoded con­ tent to have a variety of Different emotional responses. A series of improvements are designed to enable decoding emotionally diverse replies from candidate replies. Liu et al. (2017) presented an emotion regulation model on the basis of guided cognitive reappraisal under continuous external emotional stimulation. This model is able to achieve positive emotional responses from the robot. When participants are in an emotional state of weak emotional involvement, they can also respond positively to the reply, which improves the participants’ positive emotional tendencies. In order to achieve contextual coherence and natural and coherent con­ tent connection during human-computer interaction, robots are gradually endowed with external knowledge. Lowe et al. (2015) first chooses external knowledge of unstructured text relevant to the conversation content context with TFIDF (Term Frequency–Inverse Document Frequency) and subse­ quently utilizes a convolutional neural network (Recurrent Neural Network, RNN) encoder to present knowledge. Lastly, the scores of the candidate responses are computed according to the external knowledge and contextual seman­ tics to make sure the accuracy of the bot’s responses. Young et al. (2018) proposed to store the common-sense knowledge graph in an external memory module. The authors encode queries, responses, and common sense through the Tri-LSTM (Triggered Long Short-Term Memory) model. Then, they combined relevant common sense with the retrieval dialogue model to get more precise responds from the robot, resolving the issue of background common sense being lacking in HCI. A deep neural matching network-based learning framework was presented by Yang et al. (2018). Utilizing question-andanswer sessions and pseudo-associative feedback, the authors INTERNATIONAL JOURNAL OF HUMAN–COMPUTER INTERACTION score the retrieval dialogue system’s response set based on external knowledge. This has the advantage of incorporating outside information into the deep neural network, which enhances the coherence of settings in HCI. 2.2. Research status of robot content recommendation in closed domain Human-computer interaction systems in closed domains have the following two distinguishing features. First, the par­ ticipants’ input was limited to a particular domain, and the robot’s reply content is limited to a specific field. Replies to specific fields often require standardized answers. Second, robots usually play the role of facilitator in the interaction process. In this process, the relevance of the robot inter­ action environment is essential. The major goal of the closed-domain dialogue system is to guide participants to complete their demands in a specific field, and during the interaction process, the participants feel that the communi­ cation method is similar to human communication, and the communication process is natural and smooth. Closed domain task-based dialogue model frameworks are divided into two major categories, one is a pipeline model-based framework, and the other is an end-to-end model framework. In a framework on the basis of the pipeline model, intent recognition has always been a research focus in this field. Jeong and Lee (2008) suggested a coordinated probabilistic model of a triangular chain of conditional random fields. The model denotes meta-sequence and sequence labels jointly in a single graph structure, which explicitly encodes the association between them while retaining the uncertainty between the sequences. By extending the linear chain tri­ angle chain conditional random field probabilistic model, the model enables efficient inference and evaluation methods. Xu and Sarikaya (2013) suggested a neural network ver­ sion according to the triangular conditional random field algorithm model. In this model, intent tags and slot sequen­ ces are jointly modeled using their correlation, and their fea­ tures are automatically extracted through the convolutional neural network layer and shared by the intent model, achieving clearer intent discovery. Guo et al. (2014) imple­ mented a task-oriented dialogue system and solved the problem of completing various online shopping-related tasks through natural language dialogue. The authors established a task-based dialogue system for e-commerce through nat­ ural language processing technology and data resources, and realized good effects in practical applications. Yan et al. (2017) implemented generalization via successive spatial rep­ resentations and applied arithmetic operations to these rep­ resentations to realize combinatoriality, including feedforward and recurrent neural network language models. This model provides an elegant mechanism to merge the discrete syntactic structures with the representations of phrases and words in continuous space into a powerful combinatorial model to provide additional feature informa­ tion for intent detection. 3 In the last few years, with the boom in social networks and deep learning, end-to-end closed-domain dialogue sys­ tems have been developed more strongly. Liu and Lane (2017) proposed an optimized deep reinforcement learning framework for dialogue systems on the basis of end-to-end task. The dialogue agent and user simulator are jointly opti­ mized through deep reinforcement learning. The authors simulate the dialogue between the two agents and imple­ ments a reliable user simulator that achieves good results in the movie ticket booking scenario. Wen et al. (2016) pro­ posed a target-oriented trainable dialogue method and a new approach to the collection of dialog data on the basis of a new pipeline framework through neural network text input and end-to-end text output. In this article, the author con­ structs a dialogue system to achieve better results in restaur­ ant search applications. Su et al. (2016) presented an active learning Gaussian process model. Such Gaussian process runs on successive spatial dialog representations, which are produced in an unsupervised way utilizing recursive neural network codecs. This framework can greatly decrease the user feedback noise and the costs of data annotation in dia­ log strategy learning. While the aforementioned studies do, to some extent, take into account the two primary factors of external know­ ledge and emotional state during HCI, some only take into account the impact of a single interaction round and neglect the coherence of the context, or they only take into account the robot’s reaction to the emotional state in the context. The robot’s reaction is evaluated, or rather, solely the effect of contextually relevant external knowledge. We proposed an HCI model according to the ripple net­ work of knowledge graph with the goal of enhancing the emotional friendliness of the robot during the HCI process in order to address the issues of lack of background know­ ledge and low coherence of responses in the current HCI model. We examine the participants’ emotional friendliness and replicate the process of background knowledge awaken­ ing during a human-to-human conversation by introducing the external knowledge graph as the robot’s background knowledge. In accordance with the experimental data, robots with emotional measurements and prior information may evidently raise their emotional friendliness and coherence during HCI, in contrast to contrasting model techniques like MECs models. 3. Content recommendation method based on knowledge graph ripple network Human learning, life, work, and other experiences will be stored in the brain as associated memories, and these memories can be viewed as individual background know­ ledge (Richmond and Nelson, 2009). The communication process among people can be seen as a process in which background knowledge is constantly awakened. During the communication process, one party’s strong emotional desire to communicate will usually keep the conversation going. Correspondingly, during human-computer inter­ action, humans naturally hope to communicate with a 4 Z. HE knowledgeable and emotional robot. How to enable robots to use background knowledge to achieve emotional com­ munication like humans during HCI is the focus of many scholars. Our proposed model in this section simulates the interaction process between people that considers both content and emotion. The ripple network of know­ ledge graph enables the discovery of content that may be of interest to participants and the emotional friendliness of HCI realizes the calculation of the emotional process of participants. 2. basis of this. An overall raising tendency in the partici­ pants’ emotional states during the interaction process is indicative of a healthy interactive relationship. Assessment of the content connection between HCI: People communicate with one other through a process of ongoing background knowledge awakening, and the contents of communications are correlated. We subse­ quently employ this information to perform a correl­ ation analysis on the content of the human-computer dialogue and identify any potentially fascinating partici­ pant content on the knowledge network. 3.1. Problem description When two engaging individuals converse on a specific prob­ lem in an open domain, the topic’s substance will progres­ sively expand as the conversation goes on, and both parties’ prior knowledge will gradually come to light. The party with prior knowledge of the interaction process is referred to as the participant in the present HCI system. When carrying out multiple rounds of dialogue, the participants’ willingness to participate will be substantially diminished through the dialogue system, which will eventually happen in the end of the dialogue, if the system fails to present new content or if the content introduced is not relevant enough or is not emotionally expected by the participants. In Figure 1, the process of HCI is displayed. The participants in robot and HCI are represented by R and H, respectively. 3.1.1. Problem formalization From Figure 1, it can be observed that the participant’s k input in the k-th interaction system is CH : Supposing that the friendliness of the emotional interaction between the robot and the participant is R(k), what requires to be gotten is the content CRk of the robot replies to the partici­ pant in the k-th conversation. Its concrete mathematical expression is: � � k f : RðkÞ, G, CH ! CRk (1) 3.1.2. Emotional friendliness of HCI HCI is an ongoing process. The current emotional state is not only associated with the content of the current interactive dialog, but also with the content of the historical interactive dialog. The update function that defines the human-computer interaction emotional friendliness R(k) based on the current and historical interactive session content is: RðkÞ ¼ minð1, maxðRðk − 1Þ þ WðkÞ � CðkÞ, 0ÞÞ (2) Among them, R(k) is the emotional friendliness of the kth human-computer interaction, and the range of value is [0,1]. The lower the value, the poorer the emotional inter­ action state. Conversely, the larger the value, the better the emotional interaction state. The initial value of R(0) is 0.5, which suggests that the HCI association is indeterminate. W(k) is the emotional evaluation value of the interaction input, with an initial value of 0 and a range of [−1]. When their values were positive and plural, the participants’ emo­ tional states were positive and negative, respectively. With an initial value of 0, C(k) is the emotional confidence of HCI and denotes the reinforcement impact of persistently negative or positive feelings. In other words, both the emo­ tional certainty and the value of C(k) rise when the two conversations have the same emotional tendency. The degree of confidence declines when the two conversation’s emotions diverge. We will define C(k) and W(k) in detail below. Input and output: Knowledge graph G is being introduced when the system is initialized. During the interaction, the input of the partici­ k , and the pant is the content of the k-th conversation CH output of the system is the content of the k-th robot’s reply CRk : Considerations: 3.1.2.1. Human-computer interaction emotion assessment. Interactive input emotions were quantified into vectors with numerical values according to the literature (Park et al., 2011) in order to more accurately quantify and compute emotions. The six fundamental emotion states that make up the PAD emotion space’s emotion vector are happiness, dis­ gust, surprise, sadness, fear, and anger. Its specific definition is as follows: 1. hl ¼ ðEp − El ÞCl ðEp − El ÞT l ¼ 1, 2, 3, 4, 5, 6 (3) � � Among them, Ep ¼ pp , ap , dp represents the emotion of interactive input, that is, combining the PAD emotion model in psychology to analyze the semantic sense to obtain the input emotion. The values of l are 1, 2, 3, 4, 5, and 6, respectively representing the six emotions of happiness, dis­ gust, surprise, sadness, fear, and anger. El represents the coordinate set of fundamental emotional states in PAD space, which is used as a standard emotion measurement vector. Cl represents the set of covariance matrices of Assessment of emotional connection in HCI: HCI is an ongoing process of interaction, and the participants’ emotional attachment to the material influences the dia­ logue’s continuity. We first assess the human-computer dialogue’s friendliness of emotional interaction on the Figure 1. Diagram of content input and output during HCI. INTERNATIONAL JOURNAL OF HUMAN–COMPUTER INTERACTION underlying emotional states in the PAD space. Later, hl denotes the separation between the basic emotion El and interactive input emotion Ep acquired under Cl constraint. This distance corresponds to 6 emotional states. The interactive input sentiment evaluation function was defined as P(Ep), and normalize its corresponding emotion intensity l, as shown in Equation (4). To make sure that the formula makes sense, we especially define hl not to be zero, which is expressed as follows by Equation (5). 8 1=h > > > pl ¼ P6 l , hl 6¼ 0 > < k¼1 1=hk (4) l 6 X X > > > p ¼ 1, p ¼ p ¼ 0, h ¼ 0 i i l > : l i¼0 i¼lþ1 PðEp Þ ¼ ½p1 , p2 , p3 , p4 , p5 , p6 � (5) For the k-th conversation, the emotion evaluation of HCI can be defined as follows: WðkÞ ¼ p1 þ 0:6p2 þ 0:2p3 − 0:2p4 − 0:6p5 − p6 (6) The range of the emotional evaluation value W(k) is [−1]. When the value is positive, it means that the emo­ tional state of the participant is positive. On the contrary, when the value is negative, it means negative emotion. 3.1.2.2. Emotional confidence in human-computer inter­ action. Emotional certainty represents the influence of previ­ ous emotional states on subsequent emotional states. When the same emotion appears continuously, it will strengthen this emotion. Now define the dynamic change of C(k) as follows. 8 � �!!! > �WðkÞ − Wðk − 1Þ� > > � > , min 1, max 0, Cðk − 1Þ þ 1 − �� > � > > 2 > > < WðkÞWðk − 1Þ � 0 CðkÞ ¼ � � !! > � � > > min 1, max 0, Cðk − 1Þ − �WðkÞ − Wðk − 1Þ� > , > � � > 2 > > > : WðkÞWðk − 1Þ < 0 (7) The interactive emotional confidence C(k) is closely related to the interactive emotional evaluation value W(k). Continuous positive emotional evaluation values will posi­ tively promote emotional certainty and make the humancomputer interaction state more positive. Continuous negative emotional evaluation values will reversely promote emotional certainty, which enhances the negativity of the entire inter­ action state. The psychological process of genuine interper­ sonal communication is more in accordance with the emotional certainty evaluation process. 3.1.3. Knowledge graph ripple network content recom­ mendation method 3.1.3.1. Knowledge graph ripple network. The Knowledge Graph (KG) is a type of heterogeneous graph where the edges represent relationships and the nodes represent enti­ ties. Triples (tail entity, relationship, head entity) are the 5 forms that relationships and entities take to construct a het­ erogeneous network. The following benefits arise from inte­ grating knowledge graphs into recommendation systems: First, it can provide rich semantic information, allowing the recommendation system to recommend richer and more diverse content. For example, a recommendation system based on knowledge graphs can semantically link movies, music, etc. that users have previously liked, thereby recom­ mending more relevant content. Second, it can semantically link various information to enable recommender systems to better understand the interests and needs of users, thereby improving the recommendation effect. By analyzing the enti­ ties, relationships and attributes in the knowledge graph, more precise personalized recommendations can be realized. Third, it provides a structured model that can express the recommendation logic of the recommendation system more clearly, making the recommendation results easier to under­ stand and explain. Currently, there are three main categories of recommendation methods based on knowledge graphs: embedding-based knowledge graph recommendation, pathbased knowledge graph recommendation, and hybrid method-based knowledge graph recommendation. This complex relationship in the knowledge graph pro­ vides us with a deeper and broader content perspective, which corresponds to the relevance of the real objective world and provides prerequisites for the expansion of par­ ticipant dialogue content in human-computer interaction systems. A common representation of knowledge graphs is triples, namely G ¼ (H, R, T). Here, H ¼ {e1, e2, … ,eN} denotes the set of head entities in the knowledge base, N represents the entities number, R ¼ {r1, r2, … , rM} denotes the combination of connections in knowledge base, M is the entity relationships number, T is the set of tail entities in knowledge base, and T � H � R � H:H(head), R(relation), T(tail) form a triplet, namely head entity-relationship-tail entity. A simple triplet link is from Figure 2. Figure 3 illustrates the activation of underlying entities of participants by dialog entities, in which entities A and B are the entities participating in the content of the participants’ dia­ logs in a certain human-computer interaction process. The entity number of entity A’s first-level association is (1, 4, 5), and the entity number of entity B’s first-level association is (1, 8, 9). The common first-level associated entity number of entity A and entity B is 1. The entities involved are the shaded parts in Figure 3(b). The second-level related entities of entity A are numbered (2, 3, 6, 7) and those of entity B are num­ bered (2, 7). The common number of the second-level related entities of entity A and B is (2, 7), the involved entities are as shown in the shaded part in Figure 3(c). Based on this reasoning, we can conclude the entity number of the lower association hierarchy of entity A or entity B (the lower the relationship, the higher the level of association). Content that may be of interest to a participant is activated through conversation entities and propagated along hierarchical connections in the knowledge graph from strong to weak and near to far. As the number of related entities raises, the interest of the user reduces, which correlates with the shaded area in Figure 3. Such a process is similar to the propagation of water 6 Z. HE Figure 2. Example of knowledge graph perspective. Figure 3. Knowledge graph ripple network propagation model diagram. ripples from strong to weak and near to far. The water ripple’s amplitude will progressively weaken as they propagate from near to far. Similarly, the influence of dialogue entities on enti­ ties with lower correlation levels gradually becomes smaller, and during the ripple propagation process, interference super­ position effects will occur at certain entities to highlight certain entities (common related entities). Finally, the entity content that the participants are interested in is optimally selected based on their emotional tendencies. The above entire process describes the HCI model. To utilize the knowledge graph to dig out the potentially interesting content of the participants, entity extraction and disambiguation are performed on the dialogue content of the participants through entity linking (Sil and Yates, 2013), and the dialogue entity set in the interaction process is obtained, and then the entities are the set is embedded into the ripple network of the knowledge graph. The relevant sets in the rip­ ple network of knowledge graph are specified as below. According to the propagation model of the ripple network of the knowledge graph, the set of participant dialog entities that we acquired in the kth conversation is defined as below. � � Hk ¼ hk jhk 2 G (8) In which, G represents the known knowledge graph, hkand k denote the dialogue entity and dialogue round. The ternary ripple of the obtained set of participant dialog enti­ ties Hk is given in below: � � (9) Skn ¼ ðh, r, tÞjðh, r, tÞ 2 Gh 2 Hk , n ¼ 1, 2, ::, N Here, n stands for the associated entity level, eg, S11 denotes the first-level associated entity of dialogue entity in the first conversation. The set of responses from the participants is in INTERNATIONAL JOURNAL OF HUMAN–COMPUTER INTERACTION turn derived from the retrieval formula and a vector of sen­ tence feature representation v 2 Kd is obtained by using the word2Vec (Mikolov et al., 2013) method and the Embedding Average vector mean method to obtain the content of the reply set. In which, K and d stand for the feature representa­ tion vector and word vector dimension, separately. We com­ pute the probability of association pi between the sentence feature vector v and each triad (ti, ri, hi) in the first-level associated entity of ripple set Sk1 in the k-th conversation with the formula: � exp ðvT Ri hi Þ pi ¼ softmax vT Ri hi ¼ P (10) ð T Þ ðh, r , tÞ2Sk1 exp v Rh Here, hi 2 Kd and Ri 2 Kd�d stand for the entity vectors of ripple sets hi and ri separately. The entity vectors of the ripple set triad (ti, ri, hi) are acquired by the feature learning method Trans D for the knowledge graph, and the respect­ ive corresponding entity vectors stand for ti, ri, and hi. pi can be viewed as a probability that gauges the similarity between the entity hi and the word vector vin the relation Ri space. After getting the correlation probability, we later compute the effect of the dialog entity on the tail entity r of the first-level correlated entities. We can compute vector o1. X o1 ¼ pi ti (11) ðhi , ri , ti Þ2S11 Vector o1 is the first-order response of sentence feature vector v, in which ti 2 Kd : With Equations (10 and 11), the content of interest to the participants is distributed far along the hierarchical relationship of knowledge graph. The secondorder response o2 is acquired from replacing the sentence vector v in Equation (10) by the vector o1 in Equation (11). This process is repeated on ripple set, ie, the values of n in Skn are 1 and 2 separately. It stands for the secondary propagation of the participant’s conversational entities on the knowledge graph ripple network. Since too large an order response dilutes valuable information, the value of N in Equation (9) is 2 or 3. In summary, the formula for the participant’s response with respect to vector v can be represented as. H X O¼ oi (12) i¼1 The normalized content probability is: y ¼ rðOT vÞ (13) Equation (13) was defined as the content friendliness of participant, where the sigmoid function is as below: 1 1 þ exp ð−xÞ value in the range [0, 1]. As the value gets closer to 1, the participant is more satisfied with the response. 3.1.3.2. Construction of knowledge graph ripple network interaction model. First of all, a knowledge graph G (in this paper, we adopt CN-Dbpedia, a Chinese general encyclope­ dia knowledge graph developed and maintained via Fudan University) is given, and the input to the model is the con­ k , and the tent of the kth participant’s interaction input CH output is the content of the kth þ 1th robot’s reply CRkþ1 : Next, the ripple network of knowledge graph is employed for assessing the friendliness of the participant’s dialogue material, and emotional friendliness is applied to establish the participant’s continuous emotional state vector. Ultimately, the robot’s best response is identified via taking into account both the friendliness of the content and the participant’s emotional state vector. In particular, Table 1 illustrates how the ripple network of knowledge graph inter­ action model is built. 4. Experimental design and result analysis 4.1. Experimental framework We modified ChatterBot in Python to the suggested model and simulated it as text chat for performing an efficient experimental comparison of the suggested HCI model con­ tent recommendation approach. The ChatterBot framework is represented by the solid line in the model process struc­ ture presented in Figure 4, while the expanded content is represented by the dotted line. During HCI, facial expres­ sions, voice, gestures, as well as other cues are employed to evaluate emotional friendliness. 4.2. Experimental data and comparative models The experimental data is derived from the conversation material of the 2018 NLPCC task Open Domain Question Answering, ie, Chinese dialogue question and answer. In the corpus, there are 24,479 pairs of questions and answers. We designate 2500 pairs of questions and answers at random to serve as the verification set, another 2500 pairs at random to serve as the test set, and the rest of the pairs to serve as the model training set. We have chosen these four models for comparison tests in this section. (14) 1. In combination with Equations (2) and (13), we add con­ tent- and sentiment-friendliness weights to the content of candidate responses, normalized as below. 2. yv ¼ aRðkÞ þ by 3. rðxÞ ¼ (15) Where a and b are the constraint factorsa þ b ¼ 1 (the default is a ¼ b ¼ 0.5, which will be described in more detail later in the experimental discussion section). Yv takes the 7 Literature (Sutskever et al., 2014) is a dialogue model that automatically generates replies based on Seq2Seq of LSTM network. Literature (Gunther, 2019) is a ChatterBot interaction model that sorts answers and outputs them based on confidence level. Literature (Zhang et al., 2018) takes into account the “empathy” of the participants in the interaction and chooses emotionally similar replies as responses, thereby realizing an emotional MECs dialogue cognitive model. 8 Z. HE Table 1. Modeling of human-computer dialogues on the basis of knowledge graph ripple network. Input: The k-th participant inputs content CHk , known knowledge graph G; Output: The response content CRkþ1 of the robot for the k þ 1th time (1) Repeat: (2) Return the n replies with the highest semantic confidence based on the participant’s k-th interactive input, and vectorize the reply sentences to obtain their feature representations; perform entity extraction and disambiguation of the dialogue content through entity connection; (3) Calculate the emotional friendliness R(k) of the k-th participant’s interactive input according to patterns Equations (2)–(7); (4) According to Equations (8) and (9), the ripple set of associated entities is obtained; (5) According to Equations (10)–(14), the content response probability of the candidate reply is obtained; (6) According to Equation (15), the normalized values of content friendliness and emotional friendliness are obtained, that is, the satisfaction value of the candidate reply; (7) Select the maximum satisfaction value yv as the reply content; (8) k ¼ k þ 1; (9) Until the participant stops interactive input; (10) The human-computer interaction session is terminated. Figure 4. Content recommendation method process framework according to the ripple network of knowledge graph. 4. Literature (Lowe et al., 2015) is a Concept Net cognitive model that states general knowledge in an external memory module and incorporates associated general knowledge into the retrieval dialog. 4.3. Evaluation metrics The two measures we employ to objectively assess the accur­ acy of model response are Mean Average Precision (MAP)together with Mean Reciprocal Rank (MRR). Whereas MAP represents the accuracy of a particular statis­ tic, MRR reflects overall accuracy. Both indicators are defined as below: MRR ¼ k 1 X 1 jkj i¼1 rankqi 8 k > > 1 X > > AveðAi Þ < MAP ¼ jkj i¼1 Pn > > j¼1 ðrðjÞ=pðjÞÞ > > : AveðAi Þ ¼ n (16) (17) where k stands for the number of times a participant has q engaged in a conversation and ranki stands for the ordering of the i-th participant’s response in the reply set. Ave(Ai) denotes the mean accuracy of the ordering of the responses of the i-th conversation model. p(j) denotes the ordering level of the j-th answer in the adjusted response set after the model has adapted the ordering of the candidate reply set taking into account the given constraints; r(j) denotes the ordering of the j-th answer in the standard reply set; and n indicates the number of replies in the standard reply set. MAP expresses the mean accuracy of single-valued accuracy of response performance. To confirm the model’s efficacy, a manual assessment technique was employed to enlist 40 participants as needed to engage with chatbots using varying cognitive models. First, determine the length of the debate between a person and a computer by measuring each model’s efficacy in terms of time. Next, ask the volunteers to rate using the assess­ ment criteria for Sentiment and Fluency. Table 2 displays the evaluation criterion table. We assume that there are 10 candidate responses in the standard reply set, or that the number of standard reply sets INTERNATIONAL JOURNAL OF HUMAN–COMPUTER INTERACTION 9 Table 2. Evaluation indicators of ripple network content recommendation method based on knowledge graph. Fluency Evaluation index The content is relevant, grammatically fluent, and consistent with human communication. The content logic is barely relevant, and the grammatical expression is acceptable. Content lacks logical relevance, the answers are incorrect, and the expressions are confusing. Evaluation index Responses are emotionally appropriate and expressive and interesting Responding with appropriate emotion Vague expressions, meaningless replies, etc. þ2 þ1 þ0 Sentiment þ2 þ1 þ0 Table 3. Objective assessment results of various cognitive models. Models Seq2Seq ChatterBot MECs ConceptNet Ours MRR MAP 0.3729 0.4514 0.5820 0.6317 0.6492 0.4123 0.4871 0.6114 0.6513 0.6696 is 10. This allows us to compute the outcomes of the two objective evaluation indicators of MRR and MAP. Table 3 displays the results of the computation. Table 3 presents that our suggested model outperformed the other four comparison models in terms of results. The primary explanation for this is that the model sorts the can­ didate reply set based on both content and emotional friend­ liness. It limits the reply content not only in terms of the coherence of objective things but also in terms of subjective emotional friendliness. When comparing the ChatterBot and Seq2Seq models, the ConceptNet and MECs models per­ formed better than the others. The rationale is that ConceptNet presents external knowledge graphs as com­ mon-sense knowledge, and MECs take empathy into account during the interaction process. To improve the model’s performance, they take into account, respectively, background knowledge and emotional elements. Seq2Seq has the lowest grade because it produces a large number of nonsensical responses while accounting for interaction pro­ cess security. Again, objective assessment confirmed the effi­ caciousness of our suggested strategy in raising response accuracy. The impact of varying gender and age groups on the assessment of the dialogue system’s interaction effect must be taken into account throughout the process of manual evaluation. Forty participants, varying in age and gender, were asked to engage with each model, and the duration of each interaction as well as the number of rounds were recorded. Table 4 exhibits the statistical results. We then rated 40 volunteers’ satisfaction with Fluency and Sentiment according to different gender groups and different age groups. The gender group consists of 20 males and 20 females, respectively, group 1 and group 2. Table 5 displays statistical results. In the age group, 19–23 years old is group 3, and 24– 28 years old is group 4. Each age group consisted of 2 females and 2 males (19–22 years old are undergraduates, 23–25 years old are undergraduates) Those aged between 26 and 28 years old are master students, and those between 26 and 28 years old are social workers. Table 6 displays the stat­ istical results. Table 4. Statistics on the number of rounds and time of interaction between models and volunteers. Models Average number of interaction rounds/person Average interaction time/person 6.350 6.850 7.925 9.850 11.250 71.32 72.57 83.26 109.63 122.45 Seq2Seq ChatterBot MECs ConceptNet Ours Table 5. Statistics on the Fluency and Sentiment scores of each model by vol­ unteers in the gender group. Fluency Models Seq2Seq ChatterBot MECs ConceptNet Ours Group 1 0.82 1.26 1.47 1.48 1.55 Sentiment Group 2 0.75 1.18 1.41 1.46 1.48 Group 1 0.63 0.84 1.42 1.36 1.50 Group 2 0.68 0.97 1.46 1.43 1.53 Table 6. Statistics on fluency and sentiment scores of each model by volun­ teers in age groups. Fluency Models Seq2Seq ChatterNot MECs ConceptNet Ours Group 3 0.68 1.32 1.39 1.50 1.54 Sentiment Group 4 0.62 1.27 1.32 1.41 1.45 Group 3 0.67 0.82 1.50 1.43 1.54 Group 4 0.74 0.85 1.50 1.49 1.53 Table 4 shows that when in contrast to other models, vol­ unteers and the model applied in this chapter did superior in terms of the duration of interactions and the quantity of interaction rounds. Tables 5 and 6 indicate that in this chap­ ter, the model received higher results in terms of Sentiment and Fluency than other models from volunteers of varying ages and genders. The model in this chapter, which consid­ ers emotional friendliness and coherence of material, has been manually evaluated and demonstrated to be capable of extending both the number and duration of discussion rounds in HCI. 4.4. Experimental discussion We address the constraint parameters a and b in Equation (15) to examine the real effects of content and emotional friendliness on the model in more detail. We just need to talk about how a between [0,1] affects the model because there is a link between b ¼ 1–a. The two indicators, MAP and MRR, are still measured utilizing objective assessment, and their values are likewise identified via applying the number of standard answer sets (n ¼ 10). 10 Z. HE Table 7. Evaluation results of different knowledge perception models. Models ChatterBot DISAN BIMPM Ours MRR MAP 0.4512 0.5638 0.5711 0.6223 0.4354 0.5775 0.5628 0.6316 Figure 5. MAP objective evaluation results. Figure 7. Satisfaction survey of volunteers interacting with customer service robots. Figure 6. MRR objective evaluation results. Figures 5 and 6 indicate that the model in this section outperforms the MECs and ChatterBot models in the object­ ive assessment of MRR and MAP when a approaches 0, while the difference is negligible when in contrast to the ConceptNet model. The rationale is because the ConceptNet model and the model in this section only take content coherence into account when subjected to this restriction. When a approaches 1, the model in this chapter also achieves better results than the ChatterBot model and ConceptNet model in the objective assessment of MRR and MAP, however, the difference is small in comparison to the MECs model. The rationale is because both the MECs model and the model in this chapter only take emotional elements into account when faced with this limitation. The model in this chapter outperforms the comparative model in the objective assessment of MRR and MAP when a is nearer to 0.5. This is due to the fact that at that point, both content and emotional friendliness are considered, which may sub­ stantially raise response accuracy. We employed a manual evaluation technique to confirm the model’s efficacy, which was implemented by 30 online shopping volunteers interacting with chatbots with different cognitive models. The classic Likert scale in psychology was used to allow volunteers to rate the accuracy, friendliness, and acceptability of each interaction model. The scoring details are listed below: very satisfied with five points, satis­ fied with four points, unsure with three points, dissatisfied with two points, and extremely dissatisfied with one point. The indicator evaluation uses the results of calculating the two indicators MRR and MAP. In order to compute the two indicator values, we assume that there are n ¼ 10 recov­ ery sets. Table 7 presents the results. Table 7 illustrates that the knowledge perception model that presented in this section has superior outcomes in con­ trast to other model methods. The reason is that this model method provides a more profound representation of the dia­ logue content of the participants. First, we extract knowledge from the participants’ dialogue content to obtain the partici­ pant dialogue entity set. After obtaining the dialogue enti­ ties, we link the entities to form word link entities. Not only that, we also perform first-order external expansion on each entity to form word expansion entities. Secondly, we vector­ ize the obtained participant conversations and obtain a vec­ tor set of participant knowledge vectors through the knowledge-aware deep learning network. Finally, we dynam­ ically obtain the focus of participants’ attention on the basis of the attention mechanism and give the optimal content reply. Therefore, the modeling approach presented in this section can get better assessment results. In the manual evaluation, we also invited 30 volunteers to interact with each model and then perform scoring oper­ ations. Volunteers rated each model from three aspects: acceptability, accuracy, and friendliness. The statistical results after averaging are presented in Figure 7. Figure 7 displays that in the statistical results of volunteer scoring, the model approaches in this chapter are superior to other models. Specifically, the modeling approach in this chapter is slightly superior to the BIMPM and DISAN model, as well as to the ChatterBot model. For the four models, volun­ teers gave good scores for the acceptability, accuracy, and friendliness of the models during the interaction process. INTERNATIONAL JOURNAL OF HUMAN–COMPUTER INTERACTION For the ChatterBot model, volunteers rated all three items near satisfaction. Volunteers gave the BIMPM model and DISAN model a score between 4 and 4.5. The volunteers gave the model in this chapter a score of around 4.5. From the scores, we can see how satisfied the volunteers are with the model. The acceptability of the four models was affirmed by volun­ teers. Accuracy focused on the quality of responses during the customer service human-computer interaction process, while friendliness focused on the dialogue coherence during the cus­ tomer service human-computer interaction process. From the scoring, we can see that the dialogue quality and coherence of the BIMPM model and the DISAN model have reached a sat­ isfactory level. In contrast to the DISAN and BIMPM model, the dialogue quality and coherence of the model in this section have reached a better level of satisfaction. 5. Conclusions Human’s learning, work, life, as well as other experiences are held in the brain as associations. These memories can be con­ sidered as individual background knowledge. The process of interpersonal communication is the process of awakening locally relevant background knowledge under the impact of emotional factors. The content recommendation method we proposed according to the ripple network of knowledge graph considers the knowledge graph as the robot’s background knowledge. Then, we extract the potentially interesting enti­ ties of the participants and thoroughly consider the partici­ pants’ subjective emotional friendliness to make the best decision for the robot dialogue reply. We accomplish this by simulating the awakening of local associated background knowledge during the process of human-to-human communi­ cation employing the ripple network. Our suggested model can successfully enhance the emotional coherence and friend­ liness of robots during HCI, according to comparative testing data. Our suggested HCI model technique offers valuable possibilities for the development of a more intelligent and realistic HCI system, while also simulating real-world humanto-human communication. 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Emotional chatting machine: Emotional conversation generation with internal and external memory. Proceedings of the AAAI Conference on Artificial Intelligence, 32(1), 1–9. https://doi.org/10.1609/aaai.v32i1.11325 Zhou, X., & Wang, W. Y. (2017). Mojitalk: Generating emotional responses at scale. arXiv preprint arXiv:1711.04090, About the author Zhu He is a Ph.D. student currently pursuing her degree in UCSI University – Business and Management program. She is currently researching how responsible and lovable AI-based agents, both tangible and intangible, provide values to the business community. Her research interests are AI in marketing and human-AI interactions.