Metamorphic malicious code behavior detection using probabilistic inference methods

Existing antivirus programs detect malicious code based on fixed signatures; therefore, they have limitations in detecting metamorphic malicious code that lacks signature information or possesses circumventing code inserted into it. Research on the methods for detecting this type of metamorphic malicious code primarily focuses on techniques that can detect code based on behavioral similarity to known malicious code. However, these techniques measure the degree of similarity with existing malicious code using API function call patterns. Therefore, they have certain disadvantages, such as low accuracy and large detection times. In this paper, we propose a method which can overcome the limitations of existing methods by using the FP-Growth algorithm, a data mining technique, and the Markov Logic Networks algorithm, a probabilistic inference method. To perform a comparative evaluation of the proposed method's malicious code behavior detection, we performed inference experiments using malicious code with an inserted code for random malicious behavior. We performed experiments to select optimal weights for each inference rule to improve our malicious code behavior inferences’ accuracy. The results of experiments, in which we performed a comparative evaluation with the General Bayesian Network, showed that the proposed method had an 8% higher classification performance.     

心理距离视角下的行为决策

决策是指决策者对将产生不同结果的多个备择方案的评估与选择。无论决策结果涉及的是金钱、健康、环境或是其他事物,它们都同时具有多重属性,如发生的概率,发生的时间,发生的地点,发生在谁身上等,这些属性会和结果量一起影响人们对结果效用的评价和对备择方案的选择。以往有关风险决策、跨期决策和社会决策的理论分别探究结果的概率属性、时间属性和人际属性如何与结果量一起共同决定人们的效用评估与选择,并提出了各自不同的决策模型。然而,心理距离理论则认为,决策结果的概率、时间、空间、人际等属性本质上都可被表征为结果在决策者心中的心理距离。这意味着风险、跨期和社会决策模型有可能经由心理距离而得以统一。近几年来,众多研究围绕这一思想开展了一系列实验研究,分析了各种心理距离的同质性,探索了基于心理距离的心理折扣现象及其规律,探讨了时间、概率、人际、空间距离对个体决策的影响。在此基础上,未来研究还应更加重视对多特征决策的研究,探索心理距离之间的替换率和通币问题,探究心理距离的本质及其整合方式,以期形成统一的决策理论模型。     

Paranormal belief and errors of probabilistic reasoning: The role of constituent conditional relatedness in believers' susceptibility to the conjunction fallacy

The present study examines the extent to which stronger belief in either extrasensory perception, psychokinesis or life-after-death is associated with a proneness to making conjunction errors (CEs). One hundred and sixty members of the UK public read eight hypothetical scenarios and for each estimated the likelihood that two constituent events alone plus their conjunction would occur. The impact of paranormal belief plus constituents’ conditional relatedness type, estimates of the subjectively less likely and more likely constituents plus relevant interaction terms tested via three Generalized Linear Mixed Models. General qualification levels were controlled for. As expected, stronger PK beliefs and depiction of a positively conditionally related (verses conditionally unrelated) constituent pairs predicted higher CE generation. ESP and LAD beliefs had no impact with, surprisingly, higher estimates of the less likely constituent predicting fewer - not more - CEs. Theoretical implications, methodological issues and ideas for future research are discussed.     

Does goal relevant episodic future thinking amplify the effect on delay discounting?

Delay discounting (DD) is the preference for smaller immediate rewards over larger delayed rewards. Research shows episodic future thinking (EFT), or mentally simulating future experiences, reframes the choice between small immediate and larger delayed rewards, and can reduce DD. Only general EFT has been studied, whereby people reframe decisions in terms of non-goal related future events. Since future thinking is often goal-oriented and leads to greater activation of brain regions involved in prospection, goal-oriented EFT may be associated with greater reductions in DD than general goal-unrelated EFT. The present study (n = 104, M_age = 22.25, SD = 3.42; 50% Female) used a between-subjects 2 × 2 factorial design with type of episodic thinking (Goal, General) and temporal perspective (Episodic future versus recent thinking; EFT vs ERT) as between factors. Results showed a significant reduction in DD for EFT groups (p < 0.001, Cohen’s d effect size = 0.89), and goal-EFT was more effective than general-EFT on reducing DD (p = 0.03, d = 0.64).     

问题启动对跨时选择的影响研究

本研究采用2×3混合实验设计,通过控制时间距离和表征的建构水平,对不同问题启动下的跨时选择进行对比研究。实验结果显示,问题启动是影响跨时选择的重要因素,不同问题启动下的未来结果价值折扣存在显著差异。Why问题启动使个体的时间距离敏感度降低,How问题启动使个体的时间距离敏感度提高。     

Where science starts: spontaneous experiments in preschoolers' exploratory play

Probabilistic models of expected information gain require integrating prior knowledge about causal hypotheses with knowledge about possible actions that might generate data relevant to those hypotheses. Here we looked at whether preschoolers (mean: 54 months) recognize “action possibilities” (affordances) in the environment that allow them to isolate variables when there is information to be gained. By manipulating the physical properties of the stimuli, we were able to affect the degree to which candidate variables could be isolated; by manipulating the base rate of candidate causes, we were able to affect the potential for information gain. Children’s exploratory play was sensitive to both manipulations: given unambiguous evidence children played indiscriminately and rarely tried to isolate candidate causes; given ambiguous evidence, children both selected (Experiment 1) and designed (Experiment 2) informative interventions.     

时间贴现的分段性

以延迟和相对延迟时间贴现的实验范式, 用选择法、匹配法确定价值主观相等点, 探讨时间贴现的分段性。三个实验和一个问卷调查发现, 时间贴现具有分段性。被试的时间贴现有三次显著变化, 表现为三个时段时间贴现心理状态的不同: 从现在到未来2周内规避损失、偏好风险、愿意短期等待, 从未来2周起直到未来10年采取非补偿性策略、需求与风险并重、愿意长期等待, 和从未来10年起直到未来50年规避风险、聊胜于无、不愿意等待。     

成瘾人群跨期选择的神经机制及干预方法

成瘾可分为物质成瘾和行为成瘾, 两类成瘾人群在跨期选择上都表现出高时间折扣率的缺陷, 但也有各自的特异性特征。成瘾人群跨期选择缺陷的神经基础主要集中在评估网络(腹内侧前额叶、纹状体、后扣带皮层等)、认知控制网络(前额叶皮层、前扣带皮层等)和预期想象网络(海马、杏仁核等); 可利用心理训练来改善成瘾人群跨期选择缺陷, 其干预方法包括工作记忆训练、预期想象训练、金钱管理指导等。未来研究应该从成瘾者跨期选择缺陷的认知机制、3个神经网络系统的交互作用机理、行为遗传学以及开发有效的干预方法等方面展开大量研究。     

降低决策冲动性的方法及其神经机制

大量实验研究显示, 成瘾患者、多动症患者和病态赌博者在决策中表现出冲动偏好。目前研究冲动性决策偏好的经典实验范式是延迟折扣任务。通过延迟折扣任务, 心理学家揭示了冲动性决策偏好的神经机制并构建了多种理论, 包括单一系统评价理论、双系统评价理论、自我控制理论和自我参照加工理论。基于这些理论, 已经发展出了多种降低决策冲动性的方法, 包括想象未来具体事件、工作记忆训练、预先承诺以及提高血液中葡萄糖水平, 其背后的神经机制是通过认知控制和价值表征理论来实现的。未来研究方向需集中于价值计算、价值系统和多体素模式分析(MVPA)在改善决策冲动性以及内在机制研究上的应用。