In this paper, the notion of partial completion of equational theories is proposed, which is a procedure to construct a confluent term rewriting system from an equational theory without requirement of termination cond...In this paper, the notion of partial completion of equational theories is proposed, which is a procedure to construct a confluent term rewriting system from an equational theory without requirement of termination condition. A partial completion algorithm is presented with a brief description of its application in a program development system.展开更多
At present,although knowledge graphs have been widely used in various fields such as recommendation systems,question and answer systems,and intelligent search,there are always quality problems such as knowledge omissi...At present,although knowledge graphs have been widely used in various fields such as recommendation systems,question and answer systems,and intelligent search,there are always quality problems such as knowledge omissions and errors.Quality assessment and control,as an important means to ensure the quality of knowledge,can make the applications based on knowledge graphs more complete and more accurate by reasonably assessing the knowledge graphs and fixing and improving the quality problems at the same time.Therefore,as an indispensable part of the knowledge graph construction process,the results of quality assessment and control determine the usefulness of the knowledge graph.Among them,the assessment and enhancement of completeness,as an important part of the assessment and control phase,determine whether the knowledge graph can fully reflect objective phenomena and reveal potential connections among entities.In this paper,we review specific techniques of completeness assessment and classify completeness assessment techniques in terms of closed world assumptions,open world assumptions,and partial completeness assumptions.The purpose of this paper is to further promote the development of knowledge graph quality control and to lay the foundation for subsequent research on the completeness assessment of knowledge graphs by reviewing and classifying completeness assessment techniques.展开更多
This paper introduces a new approach for reservoir performance where long horizontal wellbores are extended in the porous media with the existence of closed sections.It focuses on the impact of these sections on the p...This paper introduces a new approach for reservoir performance where long horizontal wellbores are extended in the porous media with the existence of closed sections.It focuses on the impact of these sections on the pressure behavior,flow regimes,and productivity index considering different characteristics for the closed sections in terms of the length and petrophysical properties.The methodology used in this approach includes different tasks.The first is developing analytical models for the pressure drop caused by the production at a constant sandface flow rate from a horizontal wellbore where a part of it is closed.These models are developed based on the fact that the porous media with the existence of the closed sections in the horizontal wellbores consists of three regions.The first represents the porous media in the vicinity of the open section of the wellbore and extends to a distance equal to half the formation thickness while the second is the porous media of the open section that extends beyond the first region and reaches the reservoir boundary.The third region represents the porous media of the closed sections that extend from the wellbore to the reservoir boundary.In the second task,the proposed models are solved for different reservoir configurations,wellbore lengths,and closed and open section characteristics.The impact of closed sections on transient and stabilized pseudo-steady state productivity indices are demonstrated in third tacks while the analytical models of the observed flow regimes in the porous media are presented in the fourth task with a major focus given to those impacted by the closed sections.The outcomes of this study can be summarized in the following points:1)The pressure behavior,flow regimes,and productivity index are significantly influenced by the existence of closed sections.This influence is significant during early production time,but it decreases during intermediate production,however,it is not seen at late production time.2)The impact of closed sections becomes more severe when the petrophysical properties of the closed sections are greatly different from those of open sections.3)The pressure behavior of early production time is not affected by the petrophysical properties of the closed section porous media while pseudo-steady state flow is significantly impacted by these properties.4)The pressure and pressure derivative behaviors of long horizontal wellbores with long closed sections are similar to those developed in reservoirs depleted by hydraulic fractures.5)Reaching pseudo-steady state flow may need a longer time when there is a great difference in the petrophysical properties between closed and open sections,however,the length of the closed sections may not have such impact.The novel point that has reached in this study is observing a new bi-linear flow regime instead of a linear flow regime.This flow regime represents a simultaneous linear flow from the closed section porous media to the open section and from the open section to the porous media in the vicinity of the open section of the wellbore.New analytical models for the pressure and pressure derivative of this flow regime is introduced in this study.展开更多
In recent years,the development of machine learning has introduced new analytical methods to theoretical research,one of which is Bayesian network—a probabilistic graphical model well-suited for modelling complex non...In recent years,the development of machine learning has introduced new analytical methods to theoretical research,one of which is Bayesian network—a probabilistic graphical model well-suited for modelling complex non-deterministic systems.A recent study has revealed that the order in which variables are read from data can impact the structure of a Bayesian network(Kitson and Constantinou in The impact of variable ordering on Bayesian Network Structure Learning,2022.arXiv preprint arXiv:2206.08952).However,in empirical studies,the variable order in a dataset is often arbitrary,leading to unreliable results.To address this issue,this study proposed a hybrid method that combined theory-driven and data-driven approaches to mitigate the impact of variable ordering on the learning of Bayesian network structures.The proposed method was illustrated using an empirical study predicting depression and aggressive behavior in high school students.The results demonstrated that the obtained Bayesian network structure is robust to variable orders and theoretically interpretable.The commonalities and specificities in the network structure of depression and aggressive behavior are both in line with theorical expectations,providing empirical evidence for the validity of the hybrid method.展开更多
文摘In this paper, the notion of partial completion of equational theories is proposed, which is a procedure to construct a confluent term rewriting system from an equational theory without requirement of termination condition. A partial completion algorithm is presented with a brief description of its application in a program development system.
基金supported by the National Key Laboratory for Complex Systems Simulation Foundation(6142006190301)。
文摘At present,although knowledge graphs have been widely used in various fields such as recommendation systems,question and answer systems,and intelligent search,there are always quality problems such as knowledge omissions and errors.Quality assessment and control,as an important means to ensure the quality of knowledge,can make the applications based on knowledge graphs more complete and more accurate by reasonably assessing the knowledge graphs and fixing and improving the quality problems at the same time.Therefore,as an indispensable part of the knowledge graph construction process,the results of quality assessment and control determine the usefulness of the knowledge graph.Among them,the assessment and enhancement of completeness,as an important part of the assessment and control phase,determine whether the knowledge graph can fully reflect objective phenomena and reveal potential connections among entities.In this paper,we review specific techniques of completeness assessment and classify completeness assessment techniques in terms of closed world assumptions,open world assumptions,and partial completeness assumptions.The purpose of this paper is to further promote the development of knowledge graph quality control and to lay the foundation for subsequent research on the completeness assessment of knowledge graphs by reviewing and classifying completeness assessment techniques.
文摘This paper introduces a new approach for reservoir performance where long horizontal wellbores are extended in the porous media with the existence of closed sections.It focuses on the impact of these sections on the pressure behavior,flow regimes,and productivity index considering different characteristics for the closed sections in terms of the length and petrophysical properties.The methodology used in this approach includes different tasks.The first is developing analytical models for the pressure drop caused by the production at a constant sandface flow rate from a horizontal wellbore where a part of it is closed.These models are developed based on the fact that the porous media with the existence of the closed sections in the horizontal wellbores consists of three regions.The first represents the porous media in the vicinity of the open section of the wellbore and extends to a distance equal to half the formation thickness while the second is the porous media of the open section that extends beyond the first region and reaches the reservoir boundary.The third region represents the porous media of the closed sections that extend from the wellbore to the reservoir boundary.In the second task,the proposed models are solved for different reservoir configurations,wellbore lengths,and closed and open section characteristics.The impact of closed sections on transient and stabilized pseudo-steady state productivity indices are demonstrated in third tacks while the analytical models of the observed flow regimes in the porous media are presented in the fourth task with a major focus given to those impacted by the closed sections.The outcomes of this study can be summarized in the following points:1)The pressure behavior,flow regimes,and productivity index are significantly influenced by the existence of closed sections.This influence is significant during early production time,but it decreases during intermediate production,however,it is not seen at late production time.2)The impact of closed sections becomes more severe when the petrophysical properties of the closed sections are greatly different from those of open sections.3)The pressure behavior of early production time is not affected by the petrophysical properties of the closed section porous media while pseudo-steady state flow is significantly impacted by these properties.4)The pressure and pressure derivative behaviors of long horizontal wellbores with long closed sections are similar to those developed in reservoirs depleted by hydraulic fractures.5)Reaching pseudo-steady state flow may need a longer time when there is a great difference in the petrophysical properties between closed and open sections,however,the length of the closed sections may not have such impact.The novel point that has reached in this study is observing a new bi-linear flow regime instead of a linear flow regime.This flow regime represents a simultaneous linear flow from the closed section porous media to the open section and from the open section to the porous media in the vicinity of the open section of the wellbore.New analytical models for the pressure and pressure derivative of this flow regime is introduced in this study.
基金supported by National Natural Science Foundation of China(Grant No.32171089)Research Fund from Hangzhou Mingshitang Education Technology Development Co.,Ltd.(Project No.1222000035).
文摘In recent years,the development of machine learning has introduced new analytical methods to theoretical research,one of which is Bayesian network—a probabilistic graphical model well-suited for modelling complex non-deterministic systems.A recent study has revealed that the order in which variables are read from data can impact the structure of a Bayesian network(Kitson and Constantinou in The impact of variable ordering on Bayesian Network Structure Learning,2022.arXiv preprint arXiv:2206.08952).However,in empirical studies,the variable order in a dataset is often arbitrary,leading to unreliable results.To address this issue,this study proposed a hybrid method that combined theory-driven and data-driven approaches to mitigate the impact of variable ordering on the learning of Bayesian network structures.The proposed method was illustrated using an empirical study predicting depression and aggressive behavior in high school students.The results demonstrated that the obtained Bayesian network structure is robust to variable orders and theoretically interpretable.The commonalities and specificities in the network structure of depression and aggressive behavior are both in line with theorical expectations,providing empirical evidence for the validity of the hybrid method.
