Formal Modeling of Self-Adaptive Resource Scheduling in Cloud

A self-adaptive resource provisioning on demand is a critical factor in cloud computing.The selection of accurate amount of resources at run time is not easy due to dynamic nature of requests.Therefore,a self-adaptive strategy of resources is required to deal with dynamic nature of requests based on run time change in workload.In this paper we proposed a Cloud-based Adaptive Resource Scheduling Strategy(CARSS)Framework that formally addresses these issues and is more expressive than traditional approaches.The decision making in CARSS is based on more than one factors.TheMAPE-K based framework determines the state of the resources based on their current utilization.Timed-Arc Petri Net(TAPN)is used to model system formally and behaviour is expressed in TCTL,while TAPAAL model checker verifies the underline properties of the system.

A STUDY ON FORMAL MODEL INTEGRATION

Model integration is an important section of the model management research area. The paper puts forward a formalization representation of model, and presents some concepts, such as the compound model re- lation, the composite model and so on. Additionally, the existence of model integration is also analyzed in de- tail and several sufficient conditions are proved.

A formal model for access control with supporting spatial context

There is an emerging recognition of the importance of utilizing contextual information in authorization decisions. Controlling access to resources in the field of wireless and mobile networking require the definition of a formal model for access control with supporting spatial context. However, traditional RBAC model does not specify these spatial requirements. In this paper, we extend the existing RBAC model and propose the SC-RBAC model that utilizes spatial and location-based information in security policy definitions. The concept of spatial role is presented, and the role is assigned a logical location domain to specify the spatial boundary. Roles are activated based on the current physical position of the user which obtsined from a specific mobile terminal. We then extend SC-RBAC to deal with hierarchies, modeling permission, user and activation inheritance, and prove that the hierarchical spatial roles are capable of constructing a lattice which is a means for articulate multi-level security policy and more suitable to control the information flow security for safety-critical location-aware information systems. Next, con- strained SC-RBAC allows express various spatial separations of duty constraints, location-based cardinality and temporal constraints for specify fine-grained spatial semantics that are typical in location-aware systems. Finally, we introduce 9 in- variants for the constrained SC-RBAC and its basic security theorem is proven. The constrained SC-RBAC provides the foundation for applications in need of the constrained spatial context aware access control.

A formal model for integrity protection based on DTE technique

In order to provide integrity protection for the secure operating system to satisfy the structured protection class＇ requirements, a DTE technique based integrity protection formalization model is proposed after the implications and structures of the integrity policy have been analyzed in detail. This model consists of some basic rules for configuring DTE and a state transition model, which are used to instruct how the domains and types are set, and how security invariants obtained from initial configuration are maintained in the process of system transition respectively. In this model, ten invariants are introduced, especially, some new invariants dealing with information flow are proposed, and their relations with corresponding invariants described in literatures are also discussed. The thirteen transition rules with well-formed atomicity are presented in a well-operational manner. The basic security theorems correspond to these invariants and transition rules are proved. The rationalities for proposing the invariants are further annotated via analyzing the differences between this model and ones described in literatures. At last but not least, future works are prospected, especially, it is pointed out that it is possible to use this model to analyze SE-Linux security.

Formal modeling and quantitative evaluation for information system survivability based on PEPA

Survivability should be considered beyond security for information system. To assess system survivability accurately, for improvement, a formal modeling and analysis method based on stochastic process algebra is proposed in this article. By abstracting the interactive behaviors between intruders and information system, a transferring graph of system state oriented survivability is constructed. On that basis, parameters are defined and system behaviors are characterized precisely with performance evaluation process algebra （PEPA）, simultaneously considering the influence of different attack modes. Ultimately the formal model for survivability is established and quantitative analysis results are obtained by PEPA Workbench tool. Simulation experiments show the effectiveness and feasibility of the developed method, and it can help to direct the designation of survivable system.

A new formal model for privilege control with supporting POSIX capability mechanism

In order to enforce the least privilege principle in the operating system, it is necessary for the process privilege to be effectively controlled; but this is very difficult because a process always changes as time changes. In this paper, based on the analysis on how the process privilege is generated and how it works, a hierarchy implementing the least privilege principle with three layers, i.e. administration layer, functionality control layer and performance layer, is posed. It is clearly demonstrated that to bound privilege's working scope is a critical part for controlling privilege, but this is only mentioned implicitly while not supported in POSIX capability mechanism. Based on analysis of existing control mechanism for privilege, not only an improved capability inheritance formula but also a new complete formal model for controlling process based on integrating RBAC, DTE, and POSIX capability mechanism is introduced. The new invariants in the model show that this novel privilege control mechanism is different from RBAC's, DTE's, and POSIX's, and it generalizes subdomain control mechanism and makes this mechanism dynamic.

A formal model for plastic human computer interfaces

The considerable and significant progress achieved in the design and development of new interaction devices between man and machine has enabled the emergence of various powerful and efficient input and/or output devices. Each of these new devices brings specific interaction modes. With the emergence of these devices, new interaction techniques and modes arise and new interaction capabilities are offered. New user interfaces need to be designed or former ones need to evolve. The design of so called plastic user interfaces contributes to handling such evolutions. The key requirement for the design of such a user interface is that the new obtained user interface shall be adapted to the application and have, at least, the same behavior as the previous （adapted） one. This paper proposes to address the problem of user interface evolution due to the introduction of new interaction devices and/or new interaction modes. More, precisely, we are interested by the study of the design process of a user interface resulting from the evolution of a former user interface due to the introduction of new devices and/or new interaction capabilities. We consider that interface behaviors are described by labelled transition systems and comparison between user interfaces is handled by an extended definition of the bi-simulation relationship to compare user interface behaviors when interaction modes are replaced by new ones.

Research on system-of-systems combat simulation model formal specification and representation

To makesystem-of-systems combat simulation models easy to be developed and reused, simulation model formal specification and representation are researched. According to the view of system-of-systems combat simulation, and based on DEVS, the simulation model＇s fundamental formalisms are explored. It includes entity model, system-of-systems model and experiment model. It also presents rigorous formal specification. XML data exchange standard is combined to design the XML based language, SCSL, to support simulation model representation. The corresponding relationship between SCSL and simulation model formalism is discussed and the syntax and semantics of elements in SCSL are detailed. Based on simulation model formal specification, the abstract simulation algorithm is given and SCSL virtual machine, which is capable of automatically interpreting and executing simulation model represented by SCSL, is designed. Finally an application case is presented, which can show the validation of the theory and verification of SCSL.

Establishing formal state space models via quantization forquantum control systems

Formal state space models of quantum control systems are deduced and a scheme to establish formal state space models via quantization could been obtained for quantum control systems is proposed. State evolution of quantum control systems must accord with Schrdinger equations, so it is foremost to obtain Hamiltonian operators of systems. There are corresponding relations between operators of quantum systems and corresponding physical quantities of classical systems, such as momentum, energy and Hamiltonian, so Schrdinger equation models of corresponding quantum control systems via quantization could been obtained from classical control systems, and then establish formal state space models through the suitable transformation from Schrdinger equations for these quantum control systems. This method provides a new kind of path for modeling in quantum control.

Formal Verification of TASM Models by Translating into UPPAAL

Timed abstract state machine(TASM) is a formal specification language used to specify and simulate the behavior of real-time systems. Formal verification of TASM model can be fulfilled through model checking activities by translating into UPPAAL. Firstly, the translational semantics from TASM to UPPAAL is presented through atlas transformation language(ATL). Secondly, the implementation of the proposed model transformation tool TASM2UPPAAL is provided. Finally, a case study is given to illustrate the automatic transformation from TASM model to UPPAAL model.

A Novel Formal Theory for Security Protocol Analysis of Denial of Service Based on Extended Strand Space Model

Denial of Service Distributed Denial of Service （DOS） attack, especially （DDoS） attack, is one of the greatest threats to Internet. Much research has been done for it by now, however, it is always concentrated in the behaviors of the network and can not deal with the problem exactly. In this paper, we start from the security of the protocol, then we propose a novel theory for security protocol analysis of Denial of Service in order to deal with the DoS attack. We first introduce the conception of weighted graph to extend the strand space model, then we extend the penetrator model and define the goal of anti-DoS attack through the conception of the DoS-stop protocol, finally we propose two kinds of DoS test model and erect the novel formal theory for security protocol analysis of Denial of Service. Our new formal theory is applied in two example protocols. It is proved that the Internet key exchange （IKE） easily suffers from the DoS attacks, and the efficient DoS- resistant secure key exchange protocol （JFK） is resistant against DoS attack for the server, respectively.

PLC Modeling and Checking Based on Formal Method

High reliability is the key to performance of electrical control equipment. PLC combines computer technology, automatic control technology and communication technology and becomes widely used for automation of industrial processes. Some requirements of complex PLC systems cannot be satisfied by the traditional verification methods. In this paper, an efficient method for the PLC systems modeling and verification is proposed. To ensure the high-speed property of PLC, we proposed a technique of “Time interval model” and “notice-waiting”. It could reduce the state space and make it possible to verify some complex PLC systems. Also, the conversion from the built PLC model to the Promela language is obtained and a tool PLC-Checker for modeling and checking PLC systems are designed. Using PLC-Checker to check a classical PLC example, a counter-example is found. Although the probability of this logic error occurs very small, it could result in system crash fatally.

Comparison of the Molecular Interaction Volume Model with the Unified Interaction Parameter Formalism in the Fe-Cr-Ni Liquid Alloys at 1873 K

The molecular interaction volume model （MIVM） for a general ternary system was deduced in detail for further clarifying and understanding its general multicomponent expression. Both MIVM and the unified interaction parameter formalism （UIPF） can be used to predict the activities of solutes and solvents in the Fe-Cr-Ni liquid alloys. But the former employs only the infinite dilute activity coefficients, and the later is not applicable without the dilute binary and ternary interaction parameters. MIVM has a certain physical meaning from the viewpoint of statistical thermodynamics, so it is an alternative for the estimation of activity coefficients of the solutes and solvents in a dilute or finite concentration metal solution where the interaction parameters are absent or their accuracies are questionable.

基于HCPN的复杂BPMN协作模型数据流建模与验证

为了保证复杂BPMN协作模型的正确性,不仅要涵盖多实例和子进程等复杂元素,还要在检测控制流错误的同时检测数据流错误。但业务流程建模标注(BPMN 2.0)缺乏形式化语义的描述,这对模型正确性的验证造成了阻碍。因此,给出了一种具有弧权重的层次化着色Petri网(HCPN)的定义,它既可以对数据流进行形式化表示,又可以对多实例和子进程结构进行建模。进一步提出了从BPMN协作模型到HCPN模型的形式化映射方法。然后基于HCPN模型的弧权重给出了缺失、丢失和冗余3种数据流错误的定义,并提出了对应的检测算法。最后,设计了一个自动化建模与验证的框架,通过一个案例研究说明了该方法的有效性。

基于形式化方法的区块链系统漏洞检测模型

随着区块链技术在各行各业的广泛应用,区块链系统的架构变得越来越复杂,这也增加了安全问题的数量.目前,在区块链系统中采用了模糊测试、符号执行等传统的漏洞检测方法,但这些技术无法有效检测出未知的漏洞.为了提高区块链系统的安全性,提出基于形式化方法的区块链系统漏洞检测模型VDMBS(vulnerability detection model for blockchain systems),所提模型综合系统迁移状态、安全规约和节点间信任关系等多种安全因素,同时提供基于业务流程执行语言BPEL(business process execution language)的漏洞模型构建方法.最后,用NuSMV在基于区块链的电子投票选举系统上验证所提出的漏洞检测模型的有效性,实验结果表明,与现有的5种形式化测试工具相比,所提出的VDMBS模型能够检测出更多的区块链系统业务逻辑漏洞和智能合约漏洞.

金融能力、正规信贷约束与农户创业行为

基于金融能力和正规信贷约束视角,利用2017年和2019年CHFS微观数据,通过构建Probit模型实证分析金融能力对农户创业行为的影响,探讨正规信贷约束在金融能力和农户创业行为关系中发挥的中介效应。结果表明:金融能力对农户创业行为具有显著正向影响,且在考虑内生性的情况下,该结论仍然成立;中介机制检验表明,金融能力能够通过缓解正规信贷约束来促进农户创业行为;异质性分析表明,中、西部地区和三线及以下城市的农户金融能力对其创业行为的影响更为显著。据此,建议建立完善的金融能力培养体系,加大对欠发达地区的政策扶持,且提高正规信贷支持力度。

安全协议形式化分析方法研究综述

介绍了安全协议的基本概念和分类,然后对安全协议形式化分析方法进行了详细介绍,包括基于模态逻辑的方法、基于模型检测的方法、基于定理证明的方法和基于可证明安全性理论的方法。其中,基于模型检测的方法是目前应用最广泛的一种方法,因此详细介绍了一些常用的基于模型检测方法的工具。最后,总结了当前安全协议形式化分析方法的研究热点和未来的发展方向。

面向无线传感器网络的认证密钥协商机制

无线传感器网络(Wireless Sensor Networks,WSN)是物联网的重要组成部分,因为WSN能通过因特网将采集到的数据发送到云服务器.认证和密钥协商机制是一个重要的密码学概念,可以确保数据传输的安全和完整性.传感器节点是资源受限的设备,因此目前多数认证和密钥协商机制在计算效率上并不适用于WSN.针对该问题,本文提出了一种新的认证和密钥协商机制,该方案是一种基于椭圆曲线的轻量级认证和密钥协商方案.在eCK安全模型下,将方案的安全性规约到CDH数学困难假设之上,形式化的证明了方案的安全性.最后通过方案对比,表明文章所提出的方案实现了计算效率和安全属性之间的平衡.

语义任务与形式任务对二语词汇形义匹配的影响——对加工资源分配模型的验证

本研究采用拉丁方设计,考察任务类型对二语词汇即时学习的影响,并从词汇形义匹配的角度对加工资源分配模型(即TOPRA模型)的适用性进行验证。51名非英语专业一年级大学生分别在语义任务、形式任务和无任务3种条件下学习24个英语单词,之后接受单词自由回忆和单词提示回忆的即时测试。结果发现:在一语自由回忆测试中,任务类型显著影响词汇意义的学习,语义任务对词汇意义的学习有促进作用,而形式任务对词汇意义的学习有抑制作用;在二语自由回忆测试中,任务类型对词汇形式的学习没有影响;在一语和二语提示回忆测试中,任务类型显著影响二语词汇的即时学习效果,语义任务和形式任务都对词汇形义匹配知识的学习有抑制作用。本研究部分验证了TOPRA模型的适用性,希望可以为二语词汇教学提供一定的借鉴和参考。

核能装备安全控制代码自动生成软件研发与应用的构想与成果展望

目前,核能装备等安全关键系统中软件的作用越来越重要,对系统的安全稳定运行具有至关重要的影响。安全关键软件规模的增长和复杂度的增加给设计和开发高可信的软件带来了新的挑战,亟需新的软件开发和验证方法与模式。针对此需求,本文围绕核能装备安全控制代码自动生成软件研究面临的三大关键科学问题,分别开展一个基础理论、七大关键技术及一套原型系统的研究。通过核能安全控制代码自动生成软件总体设计集成与评估、核能安全控制与交互系统软件建模技术、核能安全控制系统模型分析与验证技术、核能安全控制系统可信软件代码自动生成技术等方面的研究,突破核能装备安全控制代码自动生成软件在建模、代码生成和测试验证面临的系统性技术瓶颈,建立起新的安全关键软件开发和验证方法与模式。通过可信安全控制代码自动生成软件工程化应用与认证技术研究,构建一个核能装备安全控制代码自动生成的原型系统,并在核能、汽车等领域对研究成果进行验证。通过上述研究实现以下5个方面创新:一是形式化方法与模型驱动开发融合理论,用确定的数学理论保证模型的高可信;二是状态机扩展同步数据流语言形式化定义方法,建立适用于核能、航空、汽车等场景的软件建模方法;三是基于交互式定理证明的可信代码生成器构造方法,形成经过形式化验证的可信代码生成器;四是数据驱动的测试用例智能生成方法,实现测试验证的自动化;五是一套面向核能装备控制软件的一体化研发平台,构建完整的开发和验证工具链。本文旨在以形式化和模型驱动方法为基础,对安全关键软件的建模、模型验证、代码生成、测试验证等方面进行系统性研究,以形成高可信的安全关键软件开发和验证新方法。研究成果对核能等领域安全关键软件开发相关工业软件的科学研究、技术研发、产业发展等具有十分重要的理论意义和实际应用价值。