Global dynamics of a novel multi-group model for computer worms

In this paper, we study worm dynamics in computer networks composed of many autonomous systems. A novel multigroup SIQR （susceptible-infected-quarantined-removed） model is proposed for computer worms by explicitly considering anti-virus measures and the network infrastructure. Then, the basic reproduction number of worm R0 is derived and the global dynamics of the model are established. It is shown that if R0 is less than or equal to 1, the disease-free equilibrium is globally asymptotically stable and the worm dies out eventually, whereas, if R0 is greater than 1, one unique endemic equilibrium exists and it is globally asymptotically stable, thus the worm persists in the network. Finally, numerical simulations are given to illustrate the theoretical results.

SU(3) Simple Group Model and New Z' Properties in Future Linear Colliders

In the SU（3） simple group model, the new neutral gauge boson Z＇ couples to pairs of SM fermions with couplings fixed in terms of the SM gauge couplings and depending only on the choice of the fermion embedding. In this paper, we calculate the contributions of this new particle to the processes e^＋e^-→l^＋l^-, bb^-, and cc^- and study the possibility of detecting this new particle via these processes in the future high-energy linear e^＋e^- collider（LC） experiments with √s= 500 GeV and ￡int= 340 fb^-1. We find that the new gauge boson Z＇ is most sensitive to the process e^＋e^-→b^＋b^-. As long as Mz,≤2 TeV , the absolute values of the relative correction parameter are larger than 5%. We calculate the forward-backward asymmetries and left-right asymmetries for the process e^＋e^-→c^＋c^-, with both the universal and anomaly-free fermion embeddings. Bounds on Z＇ masses are also estimated within 95% confidence level.

A modified multi-group model of angular and momentum distribution of cosmic ray muons for thickness measurement and material discrimination of slabs

Muon tomography is a capable imaging technique to measure the geometry of high-Z objects. However,most existed algorithms used in muon tomography have obscured the effects of angular distribution and momentum spectra of cosmic ray muons and reduced the spatial resolution. We present a modified multi-group model that takes into account these effects and calibrates the model by the material of lead. Performance tests establish that the model is capable of measuring the thickness of a Pb slab and identifying the material of an unknown slab on a reasonable exposure timescale, in both cases of complete and incomplete angular data. Results show that the modified multi-group model is helpful for improvements in image resolution in real applications.

Enhancing Next-Item Recommendation Through Adaptive User Group Modeling

Session-based recommender systems are increasingly applied to next-item recommendations.However,existing approaches encode the session information of each user independently and do not consider the interrelationship between users.This work is based on the intuition that dynamic groups of like-minded users exist over time.By considering the impact of latent user groups,we can learn a user’s preference in a better way.To this end,we propose a recommendation model based on learning user embeddings by modeling long and short-term dynamic latent user groups.Specifically,we utilize two network units to learn users’long and short-term sessions,respectively.Meanwhile,we employ two additional units to determine the affiliation of users with specific latent groups,followed by an aggregation of these latent group representations.Finally,user preference representations are shaped comprehensively by considering all these four aspects,based on an attention mechanism.Moreover,to avoid setting the number of groups manually,we further incorporate an adaptive learning unit to assess the necessity for creating a new group and learn the representation of emerging groups automatically.Extensive experiments prove our model outperforms multiple state-of-the-art methods in terms of Recall,mean average precision(mAP),and area under curve(AUC)metrics.

Interpersonal Perception in Virtual Groups: Examining Homophily, Identification and Individual Attraction Using Social Relations Model in Network

With the penetration of the Internet, virtual groups have become more and more popular. The reliability and accuracy of interpersonal perception in the virtual environment is an intriguing issue. Using the Social relations model (SRM) [1], this paper investigates interpersonal perception in virtual groups from a multilevel perspective. In particular, it examines the following three areas: homophily, identification, and individual attraction, and explores how much of these directional and dyadic relational evaluations can be attributed to the effect of the actor, the partner, and the relationship.

SU(3) simple group model and single top production at the e^-γ colliders

In the framework of the SU（3） simple group model, we consider the single top quark production process e^-γ →vebt^-. We find that the correction effects on the process mainly come from the terms of the tree-level Wqq＇ couplings. In the reasonable parameter space of the SU（3） simple group model, the deviation of the total production cross section σ^tot from its SM value is larger than 5%, which might be detected in the future high energy linear e^＋e^- collider （LC） experiments.

GLOBAL STABILITY OF EXTENDED MULTI-GROUP SIR EPIDEMIC MODELS WITH PATCHES THROUGH MIGRATION AND CROSS PATCH INFECTION

In this article, we establish the global stability of an endemic equilibrium of multi-group SIR epidemic models, which have not only an exchange of individuals between patches through migration but also cross patch infection between different groups. As a result, we partially generalize the recent result in the article [16].

Modeling walking behavior of pedestrian groups with floor field cellular automaton approach

Walking in groups is very common in a realistic walking environment. An extended floor field cellular automaton （CA） model is therefore proposed to describe the walking behavior of pedestrian groups, This model represents the motion of pedestrian groups in a realistic way. The simulation results reveal that the walking behavior of groups has an important but negative influence on pedestrian flow dynamics, especially when the density is at a high level. The presence of pedestrian groups retards the emergence of lane formation and increases the instability of operation of pedestrian flow. Moreover, the average velocity and volume of pedestrian flow are significantly reduced due to the group motion. Meanwhile, the parameter-sensitive analysis suggests that pedestrian groups should make a compromise between efficient movement and staying coherent with a certain spatial structure when walking in a dense crowd.

Group Decision-Making Model of Renal Cancer Surgery Options Using Entropy Fuzzy Element Aczel-Alsina Weighted Aggregation Operators under the Environment of Fuzzy Multi-Sets

Since existing selection methods of surgical treatment schemes of renal cancer patients mainly depend on physicians’clinical experience and judgments,the surgical treatment options of renal cancer patients lack their scientifical and reasonable information expression and group decision-making model for renal cancer patients.Fuzzy multi-sets(FMSs)have a number of properties,which make them suitable for expressing the uncertain information of medical diagnoses and treatments in group decision-making(GDM)problems.To choose the most appropriate surgical treatment scheme for a patient with localized renal cell carcinoma(RCC)(T1 stage kidney tumor),this article needs to develop an effective GDM model based on the fuzzy multivalued evaluation information of the renal cancer patients.First,we propose a conversionmethod of transforming FMSs into entropy fuzzy sets(EFSs)based on the mean and Shannon entropy of a fuzzy sequence in FMS to reasonably simplify the information expression and operations of FMSs and define the score function of an entropy fuzzy element(EFE)for ranking EFEs.Second,we present the Aczel-Alsina t-norm and t-conorm operations of EFEs and the EFE Aczel-Alsina weighted arithmetic averaging(EFEAAWAA)and EFE Aczel-Alsina weighted geometric averaging(EFEAAWGA)operators.Third,we develop a multicriteria GDM model of renal cancer surgery options in the setting of FMSs.Finally,the proposed GDM model is applied to two clinical cases of renal cancer patients to choose the best surgical treatment scheme for a renal cancer patient in the setting of FMSs.The selected results of two clinical cases verify the efficiency and rationality of the proposed GDM model in the setting of FMSs.

The Game Model Analysis between the Individual and the Group

This paper analyses the game model between the individual and the group that has the characteristics of Stackelberg model in traditional game theory and replicator dynamic model in evolutionary game theory. In the first phase of game, the bounded rationality group players adopt the replicator dynamic behavior. Secondly, the full rationality individual player decides the own response function by the strategies distribution of group players. The shortsighted individual player will take the risk-dominant strategy. This model has some unique characteristics.

Performance Evaluation of Routing Protocols on the Reference Region Group Mobility Model for MANET

Group mobility is prevalent in many mobile ad hoc network (MANET) applications, such as disaster recovery, military operations, searching and rescue activities. Group partition, as an inherent phenomenon in group mobility, may occur when mobile nodes move in diverse mobility patterns and it causes the network to be partitioned into disconnected components. It may result in severe link disconnections, which interrupts network communications. To address this concern, we proposed a novel group mobility model in this paper, namely the Reference Region Group Mobility model, which can be used to mimic group operations in MANETs, i.e. group partitions and mergers. Based on this model, a comprehensive study on the impact of group partitions to the performance of network routing protocols are carried out by evaluating two well-known routing protocols, namely the Ad Hoc On-demand Distance Vector Routing protocol (AODV) and the Dynamic Source Routing protocol (DSR). The simulation results reflect that group partitions have a significant impact to the performance of network routing protocols.

Study on Agency Models within Internal Capital Market of Enterprise Group

In order to overcome the shortcomings brought up by the single-layer agency relation analyses of agency problems within enterprise group, two-tiered agency models in the internal capital market are set up, and how rent-seeking behaviors of member firms＇ managers affect investment allocation decision made by headquarters manager is demonstrated. From equilibrium solutions of the model, it＇s inferred that the larger the divergence of member firm＇s productivity is, the higher probability of investment allocation distortion is.

Derivation of a second-order model for Reynolds stress using renormalization group analysis and the two-scale expansion technique

With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic field.At a low-order two-scale expansion,applying the mode coupling approximation in the Yakhot-Orszag renormalization group method to analyze the fluctuating field,the Reynolds-average terms in the Reynolds stress transport equation,such as the convective term,the pressure-gradient-velocity correlation term and the dissipation term,are modeled.Two numerical examples：turbulent flow past a backward-facing step and the fully developed flow in a rotating channel,are presented for testing the efficiency of the proposed second-order model.For these two numerical examples,the proposed model performs as well as the Gibson-Launder （GL） model,giving better prediction than the standard k-ε model,especially in the abilities to calculate the secondary flow in the backward-facing step flow and to capture the asymmetric turbulent structure caused by frame rotation.

Hierarchical Merging &Generalization Method of Three-Dimension City Model Group Based on the Theory of Spatial Visual Cognition

In order to simplify the three-dimensional building group model, this paper proposes a clustering generalization method based on visual cognitive theory. The method uses road elements to roughly divide scenes, and then uses spatial cognitive elements such as direction, area, height and their topological constraints to classify them precisely, so as to make them conform to the urban morphological characteristics. Delaunay triangulation network and boundary tracking synthesis algorithm are used to merge and summarize the models, and the models are stored hierarchically. The proposed algorithm should be verified experimentally with a typical urban complex model. The experimental results show that the efficiency of the method used in this paper is at least 20% higher than that of previous one, and with the growth of test data, the higher efficiency is improved. The classification results conform to human cognitive habits, and the generalization levels of different models can be relatively unified by adaptive control of each threshold in the clustering generalization process.

Exact solutions to drift-flux multiphase flow models through Lie group symmetry analysis

In the present paper, Lie group symmetry method is used to obtain some exact solutions for a hyperbolic system of partial differential equations （PDEs）, which governs an isothermal no-slip drift-flux model for multiphase flow problem. Those sym- metries are used for the governing system of equations to obtain infinitesimal transforma- tions, which consequently reduces the governing system of PDEs to a system of ODEs. Further, the solutions of the system of ODEs which in turn produces some exact solutions for the PDEs are presented. Finally, the evolutionary behavior of weak discontinuity is discussed.

Concave Group Selection of Nonparameter Additive Accelerated Failure Time Model

In this paper, we have studied the nonparameter accelerated failure time (AFT) additive regression model, whose covariates have a nonparametric effect on high-dimensional censored data. We give the asymptotic property of the penalty estimator based on GMCP in the nonparameter AFT model.

Physical modeling of behaviors of cast-in-place concrete piled raft compared to free-standing pile group in sand

Similar to free-standing pile groups, piled raft foundations are conventionally designed in which the piles carry the total load of structure and the raft bearing capacity is not taken into account. Numerous studies indicated that this method is too conservative. Only when the pile cap is elevated from the ground level,the raft bearing contribution can be neglected. In a piled raft foundation, pileesoileraft interaction is complicated. Although several numerical studies have been carried out to analyze the behaviors of piled raft foundations, very few experimental studies are reported in the literature. The available laboratory studies mainly focused on steel piles. The present study aims to compare the behaviors of piled raft foundations with free-standing pile groups in sand, using laboratory physical models. Cast-in-place concrete piles and concrete raft are used for the tests. The tests are conducted on single pile, single pile in pile group, unpiled raft, free-standing pile group and piled raft foundation. We examine the effects of the number of piles, the pile installation method and the interaction between different components of foundation. The results indicate that the ultimate bearing capacity of the piled raft foundation is considerably higher than that of the free-standing pile group with the same number of piles. With installation of the single pile in the group, the pile bearing capacity and stiffness increase. Installation of the piles beneath the raft decreases the bearing capacity of the raft. When the raft bearing capacity is not included in the design process, the allowable bearing capacity of the piled raft is underestimated by more than 200%. This deviation intensifies with increasing spacing of the piles.

萨提亚模式团体辅导在大学生自杀意念干预中的应用效果

目的探讨萨提亚模式团体辅导对大学生自杀意念的干预效果,为大学生自杀行为的防控提供依据。方法采用随机整群抽样方法选取某高校大二年级的20个班的学生作为调查对象,随机分为干预组和对照组,每组10个班,干预组采用萨提亚模式团体辅导进行干预,对照组不采取任何干预。随访干预3个月,对2组大学生的自杀意念、生命意义及自我和谐进行比较分析。结果干预后,干预组的自杀意念检出率(6.13%)低于对照组(10.31%)及干预前(11.74%)(P<0.05);干预组对自杀行为的态度、对自杀者的态度、对自杀者家属的态度和对安乐死的态度得分分别为(2.98±0.56)分、(2.81±0.45)分、(2.97±0.36)分和(2.95±0.61)分,均高于对照组及干预前自身得分(P<0.05);干预组生命意义得分和寻求意义得分分别为(25.15±3.12)分和(26.82±3.63)分,均高于对照组得分(P<0.05);干预组自我与经验的不和谐、自我的灵活性和自我的刻板性得分分别为(45.32±8.21)、(47.81±8.27)和(16.03±3.92)分,与对照组相比差异均有统计学意义(P<0.05)。结论萨提亚模式团体辅导对大学生自杀意念有着积极的干预作用,值得在高校推广。

Phase Diagrams of the Semi-Infinite Blume-Capel Model with Mixed Spins (SA = 1 and SB = 3/2) by Migdal Kadanoff Renormalization Group

We study the mixed spin-1 and spin-3/2 Blume-Capel model under crystal field in the tridimensional semi-infinite case. This has been done by using the real-space renormalization group approximation and specifically the Migdal-Kadanoff technique. As a function of the ratio R of bulk and surface interactions and the ratios R1 and R2 of bulk and surface crystals fields on the spin-1 and spin-3/2 respectively, we have determined various types of phase diagrams. Besides second- order transition lines, first-order phase transition lines terminating at tricritical points are obtained. We found that there existed nine main types of phase diagram showing a variety of phase transitions associated with the surface, including ordinary, extraordinary, surface and special phase transitions.

基于组基轨迹模型的全膝关节置换术病人心理弹性轨迹及影响因素

目的:追踪全膝关节置换术后病人心理弹性的动态变化,并探究轨迹的相关影响因素。方法:选取2022年7月—2023年2月青岛市某三级甲等医院关节外科接受全膝关节置换术的病人为研究对象,在病人入院当天、术后3 d、术后2周拆线当日、术后1个月复诊当日、术后3个月复诊时调查病人的心理弹性水平,使用组基轨迹模型识别心理弹性变化轨迹及轨迹类别,采用多元Logistic回归分析不同轨迹的影响因素。结果:经模型拟合,最后得出4条不同的心理弹性轨迹,分别为低心理弹性平稳组、中心理弹性平稳组、低心理弹性下降组、高心理弹性上升组。多元Logistic回归分析结果显示,文化程度、领悟社会支持、正负性情绪为全膝关节置换术病人心理弹性轨迹的影响因素(P<0.05)。结论:全膝关节置换术病人心理弹性存在4个异质性轨迹亚组,且随时间而发生变化,但大多数病人在术后可以保持平稳水平。文化程度、领悟社会支持、正负性情绪为病人心理弹性的影响因素。