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The determination of virtual constraints is always one of the key and difficult problems in traditional mobility calculation. To make mobility calculation simple, considering avoiding virtual constraints, some new formulae have been presented, however these formulae can hardly intuitively reflect general link group’s restrictions on output member and its influences on independence of output parameters, which is premise to the judgment of the properties of mobility. Towards the problem to reveal the intrinsic relationship between the degree of freedom(DOF) of a mechanism, the link group, and the dimension of output parameters, also to avoid determination of virtual constraint, based on the new concepts of the “DOF of general link group” and “node parameters”, a new formula in the calculation of the mobility of mechanisms is presented that is expressed with DOFs of the general link groups and rank of motion parameters of base point of the output link. It is named GOM(mobility of groups and output parameter) formula. On the basis of new concepts of “effective parameters” and “invalid parameters”, a rule is put forward for solving the DOF of mechanisms with invalid parameters by GOM formula, that is, the base point parameters are the subset of effective parameters of link group. Thereafter, several examples are enumerated and the results coincide with the prototype data, which proves the validity of the proposed formula. Meanwhile, it is obtained that the necessary and sufficient condition for the judgment of output parameters independence is that each of the DOF of the link group is not less than zero. The proposed formula which is simple in calculation provides theoretical basis for the judgment of independence of output parameters and provides references for type synthesis of novel parallel mechanisms with independence requirements of their output parameters. [ABSTRACT FROM AUTHOR]

Embedded systems found in critical infrastructures require tight information flow controls to prevent unintended interference between different system components. These critical systems require extensive testing and verification to ensure strict enforcement of information flow policy. To assist in this process, gate level information flow tracking (GLIFT) has been proposed to expose all flows of information through Boolean gates. However, the current work in this realm only considers a two-level security lattice (\tt LOW \sqsubset \tt HIGH). In this letter, we expand the GLIFT method to multilevel security lattices and provide an analysis of the overheads using IWLS benchmarks. Results show that expanding GLIFT to multilevel security lattices produces overheads and we discuss potential research on its applications. [ABSTRACT FROM PUBLISHER]

In 2005, Gogu, a Frenchman, analyzed 35 different existing formulas for mobility calculation and pointed that the formulas for quick mobility calculation had some limitations and were not general. Therefore, looking for a general and simple mobility formula is still a hot topic in mechanisms. At the meantime, it is also an important topic to complete the mechanism theory. Gogu proposed a new method that can avoid determining virtual constraints in 2008, but the method is still not general. To solve the problem, this paper defines the new concepts of link-group rank, general-kinematic-pair rank, virtual pair, virtual loop, and virtual-loop rank, and gives a new simple and general formula. Our method converts multi-loop mechanisms into some independent virtual loops, simplifies the problem, avoids calculating virtual constraints, and reduces the calculation difficulty. It is proved that the new formula is simple, general and effective through the mobility analysis of several different kinds of mechanisms. The application of this formula will provide great convenience for general engineers in mobility calculation. [ABSTRACT FROM AUTHOR]

Focusing on dropping packets attacks in sensor networks, we propose a model of dropping packets attack-resistance as a repeated game based on such an assumption that sensor nodes are rational. The model prevents malicious nodes from attacking by establishing punishment mechanism, and impels sensor networks to reach a collaborative Nash equilibrium. Simulation results show that the devised model can effectively resist the dropping packets attacks(DPA) by choosing reasonable configuration parameters. [ABSTRACT FROM AUTHOR]

The article proposes a general approach for solving the unified formulas of the constrained Jacobian matrix and constrained Hessian matrix of three translational and one rotational (3T1R) parallel manipulators (PMs). First, based on the constraint properties of PMs, the constrained couples of the limbs are divided into two categories: invariable and variable constrained couples. The unified 2 × 6 constrained Jacobian matrix and 2 × 6 × 6 constrained Hessian matrix of the 3T1R PM are established. Then, a typical 2-(UPU)2R PM is selected, and the 6 × 6 Jacobian matrix and 6 × 6 × 6 Hessian matrix of the mechanism are deduced. The singularity of the mechanism is analyzed based on the 6 × 6 Jacobian matrix. Finally, the kinematics are derived, and results demonstrating the proposed method were provided. [ABSTRACT FROM AUTHOR]

Interactive diversity and interactive identity are two common behavioral patterns. Interactive identity, where each individual takes identity behavior to all its neighbors, and interactive diversity, where each individual takes diversity behaviors to its different neighbors. However, most previous researches mainly focused on study these two behaviors separately. So how the cooperation dynamics will perform when two behaviors are mixed in population still needs a reasonable explanation. In this paper, we study the cooperation evolution process when players take interactive diversity and identity are mixed in population. This model is applied for prisoner dilemma game on square lattice. When studying mixed population including both interactive in various proportions we find out the damage of cooperation. On the contrary, when player taking interactive diversity or players taking interactive identity exist alone in the population cooperation will be improved. To figure out the internal dynamic, we plot different kinds of strategy pair evolution process and the distribution of strategy and player when different proportion. The results of our study reveal that for only players taking interactive diversity or identity, defectors form distinct shape of clusters, while when two typed players are mixed distribute in network, defectors will form large and connected clusters, which is the crucial to maintain existence of defectors. [ABSTRACT FROM AUTHOR]

To ensure the security of highly sensitive remote sensing images (RSIs) during their distribution, it is essential to implement effective content security protection methods. Generally, secure distribution schemes for remote sensing images often employ cryptographic techniques. However, sending encrypted data exposes communication behavior, which poses significant security risks to the distribution of remote sensing images. Therefore, this paper introduces deep information hiding to achieve the secure distribution of remote sensing images, which can serve as an effective alternative in certain specific scenarios. Specifically, the Deep Information Hiding for RSI Distribution (hereinafter referred to as DIH4RSID) based on an encoder–decoder network architecture with Parallel Attention Mechanism (PAM) by adversarial training is proposed. Our model is constructed with four main components: a preprocessing network (PN), an embedding network (EN), a revealing network (RN), and a discriminating network (DN). The PN module is primarily based on Inception to capture more details of RSIs and targets of different scales. The PAM module obtains features in two spatial directions to realize feature enhancement and context information integration. The experimental results indicate that our proposed algorithm achieves relatively higher visual quality and secure level compared to related methods. Additionally, after extracting the concealed content from hidden images, the average classification accuracy is unaffected. [ABSTRACT FROM AUTHOR]

Abstract: Rigid sub-chain detection and isomorphism identification are two of the most difficult problems in the computer-aided structure synthesis of kinematic chains. This paper aims to find an efficient solution which can be fulfilled within the computer itself to the problem of rigid sub-chain detection of planar kinematic chains, especially for complex planar mechanisms. Based on the array representation of the loops of kinematic chains, this paper first introduces two operations of loops, the “Θ” and “⊕” operations. Then a new theory of structure decomposition of kinematic chains is proposed on the basis of the concept of the independent loop set. After that a new method grounded on the theory is proposed for rigid sub-chain detection. Finally, the optimized algorithm for structure decomposition is presented and the corresponding program for rigid sub-chain detection is developed as well. [Copyright &y& Elsevier]

Timing channels are becoming a critical threat to hardware security. When exploited, secret information can be revealed by analyzing the execution time statistically. There are a variety of methods for detecting timing channels such as statistical analysis, testing and formal verification. However, existing methods cannot guarantee that the timing channels can be identified due to limited test coverage or high performance overhead. In this work, we introduce a novel model for evaluating timing variations of the hardware design. Furthermore, we propose a systematical solution that integrates time label enhanced tracking logic and formally verifies the timing invariant property of hardware designs in order to identify hardware timing channels. We demonstrate our solution on several hardware implementations, including arithmetic units, cryptographic cores and cache. The proof results show that our solution can detect hardware timing channels effectively. • Developing an IFT model with time label to detect hardware timing channels. • Formally verifying timing invariant property of hardware design. • Demonstrating the timing invariant property across several hardware designs. [ABSTRACT FROM AUTHOR]