CP-ABE Based Privacy-Preserving User Profile Matching in Mobile Social Networks.

Privacy-preserving profile matching, a challenging task in mobile social networks, is getting more attention in recent years. In this paper, we propose a novel scheme that is based on ciphertext-policy attribute-based encryption to tackle this problem. In our scheme, a user can submit a preference-profile and search for users with matching-profile in decentralized mobile social networks. In this process, no participant's profile and the submitted preference-profile is exposed. Meanwhile, a secure communication channel can be established between the pair of successfully matched users. In contrast to existing related schemes which are mainly based on the secure multi-party computation, our scheme can provide verifiability (both the initiator and any unmatched user cannot cheat each other to pretend to be matched), and requires few interactions among users. We provide thorough security analysis and performance evaluation on our scheme, and show its advantages in terms of security, efficiency and usability over state-of-the-art schemes

Scheduling Independent Partitions in Integrated Modular Avionics Systems.

Recently the integrated modular avionics (IMA) architecture has been widely adopted by the avionics industry due to its strong partition mechanism. Although the IMA architecture can achieve effective cost reduction and reliability enhancement in the development of avionics systems, it results in a complex allocation and scheduling problem. All partitions in an IMA system should be integrated together according to a proper schedule such that their deadlines will be met even under the worst case situations. In order to help provide a proper scheduling table for all partitions in IMA systems, we study the schedulability of independent partitions on a multiprocessor platform in this paper. We firstly present an exact formulation to calculate the maximum scaling factor and determine whether all partitions are schedulable on a limited number of processors. Then with a Game Theory analogy, we design an approximation algorithm to solve the scheduling problem of partitions, by allowing each partition to optimize its own schedule according to the allocations of the others. Finally, simulation experiments are conducted to show the efficiency and reliability of the approach proposed in terms of time consumption and acceptance ratio

Modelling the Embedded Control System Using iUML-B Pattern State Machine

Developing the formal model based on the Event-B design pattern is an excellent method to improve the development efficiency of the embedded control system and improve the reusability of the formal model. However, the instantiation of the Event-B design pattern requires the manual writing of a large number of model codes, which brings a great deal of learning cost and coding burden to the engineering staff. In this paper, we propose a modelling approach for formal development of control systems based on the application of iUML-B state machine patterns to model the four synchronization patterns of the typical control system. Then, we use the instantiation of iUML-B pattern state machine to establish a typical multilevel control system's Event-B model. The simulation results show that the event trace of the model obtained using our method is the same as that of the corresponding model obtained using the traditional Event-B design pattern. Compared with the traditional Event-B design pattern method, our method can greatly reduce the manual coding burden in the modelling process. The system model expressed using the iUML-B pattern state machine can be easily mapped to the labelled transition system so as to verify the behavioural properties of the model

A LTS Approach to Control in Event-B

In Event-B, people need to use control variables to constrain the order of events, which is a time-consuming and error-prone process. This paper presents a method of combining labeled transition system and iUML-B to complete the behavior modeling of system, which is more convenient and practical for engineers who are accustomed to using the automaton to build a system behavior model. First, we use labeled transition system to establish the behavior model of the system. Then we simulate and verify the event traces of the labeled transition system behavior model. Finally, we convert labeled transition system model into iUML-B state machine and use it to generate the corresponding control flow model. We use Abrial’s bounded retransmission protocol to demonstrate the practicality of our approach. The simulation results show that the system behavior model generated by the iUML-B state machine has the same event trace as the corresponding labeled transition system model

Schedulability Analysis of Non-Preemptive Strictly Periodic Tasks in Multi-Core Real-Time Systems

Non-preemptive tasks with strict periods are usually adopted in practical real-time systems where missing deadlines may lead to catastrophic situations. Their schedulability analysis plays a crucial role in guiding the design and development of such real-time systems. In this paper, we study the schedulability analysis problem of partitioned non-preemptive scheduling for strictly periodic tasks on multiprocessors. We propose a set of schedulability conditions, which determines whether a new task can be scheduled on a processor without changing the offsets of the existing tasks and identifies all valid start time offsets for the new task if it is schedulable. Based on these conditions, we present a task assignment algorithm, which is not optimal, but provides an upper bound on the number of cores required by a periodic task set. We illustrate this algorithm with a practical example and conduct stimulation experiments with randomly generated task sets to evaluate the performance of our approach from several aspects

A Simulation and Verification Platform for Avionics Systems Based on Future Airborne Capability Environment Architecture

Avionics systems, which determine the performance, stability, and safety of aircraft, are a crucial part of aircraft. With the rapid development of the aviation industry, there are many serious problems in the process of the traditional simulation and verification of avionics systems, especially in the aspects of poor reusability of the hardware and software, poor real-time data interaction, and the high cost of development. In order to solve these problems, a simulation and verification platform for avionics systems based on the Future Airborne Capability Environment (FACE) architecture has been designed by using component and memory database technology. First, a general architecture is designed by referencing the FACE architecture, which allows flexible access to software and hardware resources of avionics systems. Second, the key technologies involved in the platform are described in detail, including scheduling management, communication management, and configuration management, which provide technical support for the simulation and verification of avionics systems. Finally, the simulation and verification environment of avionics systems is established, which realizes data interaction and management of various models, and improves the efficiency of the development and implementation of avionics systems

A Simulation and Verification Platform for Avionics Systems Based on Future Airborne Capability Environment Architecture

Avionics systems, which determine the performance, stability, and safety of aircraft, are a crucial part of aircraft. With the rapid development of the aviation industry, there are many serious problems in the process of the traditional simulation and verification of avionics systems, especially in the aspects of poor reusability of the hardware and software, poor real-time data interaction, and the high cost of development. In order to solve these problems, a simulation and verification platform for avionics systems based on the Future Airborne Capability Environment (FACE) architecture has been designed by using component and memory database technology. First, a general architecture is designed by referencing the FACE architecture, which allows flexible access to software and hardware resources of avionics systems. Second, the key technologies involved in the platform are described in detail, including scheduling management, communication management, and configuration management, which provide technical support for the simulation and verification of avionics systems. Finally, the simulation and verification environment of avionics systems is established, which realizes data interaction and management of various models, and improves the efficiency of the development and implementation of avionics systems

Scheduling Non-preemptive Tasks with Strict Periods in Multi-core Real-time Systems

Non-preemptive tasks with strict periods are usually adopted in practical multi-core real-time systems when continual sampling and processing of data are required. Systems designers need to provide a proper scheduling strategy such that the tasks’ deadlines will be met even under the worst-case conditions. In this paper, we study the scheduling problem of non-preemptive tasks with strict periods in multi-core real-time systems. We first derive a necessary and sufficient condition to determine whether a new task is schedulable upon a multi-core platform without changing the allocations of the existing tasks. Then, with a game theory analogy, we design a recursive method to calculate the maximum permissible execution time for a given task, and propose a new schedulability condition used when the start time and processor assignments of the existing tasks can be modified. Finally, based on the conditions derived previously, we present a task assignment algorithm, which not only provides valid allocations for all tasks, but also obtains the minimum number of processors required by the system. Simulation experiments with randomly generated task sets have been conducted to show the high efficiency and reliability of the proposed approach