Net operation

Abstract: As system complexity increases, the role of Model Based Development is more and more important. Several modeling formalisms are widely used when considering the area of hardware-software co-design of embedded systems. The goal of the work presented in this paper is to contribute for the usage of Petri nets as the system-level specification language. Techniques for system model partitioning into components are a major concern within co-design methodologies. This paper proposes a net operation, called net splitting, able to decompose a Petri net model into Petri net sub-models using synchronous communication channels. The operation is based on the definition of a valid cutting set. Specific rules are presented in order to obtain the sub-models from the initial one. The generated sub-models are associated with components to be executed concurrently, allowing a distributed execution of the initial model. On the other hand, at the implementation level, it is necessary to accommodate a severe deviation on synchronous communication channel execution semantics (as far as the components are in execution in different controllers and zero time delay is not possible to obtain). For some specific situations, initial model properties are not preserved considering execution of components obtained after net splitting operation. Although, it is possible to anticipate the impact of using specific communication channels models at the implementation level. For that end, a second step on property verification is needed in order to validate a specific partitioning solution. An illustrative example applying the referred mechanisms is presented.

Abstract: The utility model relates to a comprehensive railway repairing operation vehicle; the technical scheme is as follows: two bogies are arranged below the vehicle body; a hydraulic transmission device for providing power is suspended below the vehicle body; the front end of the vehicle body is provided with a cab; and the rear end of the cab is provided with a repairing operation material platform. Different operation devices can be arranged on the repairing operation material platform and are combined into the repairing operation vehicle with different functions; and the vehicle mainly comprises a whole carriage heavy rail vehicle, a public work repairing vehicle, a contact net operation vehicle, a bridge inspection vehicle, an aerial operation vehicle and the like. The utility model realizes that a single vehicle not only transport workers and operation equipment to an operation site but also completes the functions of relevant repairing operation, and simultaneously can transport waste and old materials after the operation.

Abstract: The invention discloses a line loss analysis method based on a power distribution automation platform. The line loss analysis method based on the power distribution automation platform is characterized by comprising the following steps: getting basic data, integrating relative data with different types of a plurality of systems by means of an information interact bus carrier and an interface message and is unified, analyzed and shared to the power distribution automation platform so that the basic data can be provided for analysis and application of line losses, and automatically getting the interface data before two days everyday; getting operation mode data, the whole net operation modes are recorded by the power distribution automation platform everyday, when the daily line losses is calculated, times are adjusted according to an operation mode of a line each day and an operation mode section at a certain moment is selected to be used as a computational frame; calculating line losses, according to the gotten interface data and the operation mode data each day, the line losses before two days is calculated and analyzed so that accurate instantaneity of calculation and query of the line losses are ensured. The line loss analysis method based on the power distribution automation platform can achieve the accurate instantaneity of calculation and analysis of the net distribution line losses and ensure timeliness and accuracy of calculation.

Abstract: Model based development within the area of hardware-software embedded systems co-design has been used as a major attitude to support embedded system complexity increasing during the last decade. Several modeling formalisms are very well matched for usage within this area. One of the main goals of the work presented in this paper is to contribute for the usage of Petri nets as the system-level specification language within model-based development of embedded systems using co-design techniques. System model partitioning into modules and components ready to be implemented in hardware or software and be deployed into a distributed platform is a major concern within co-design methodologies. A net operation, called net splitting, is used in this paper in order to decompose a Petri net model into several Petri net submodels, which will be executed in parallel using synchronous communication channels. Those Petri net sub-models are seen as modules or components ready to be used for distributed execution of the initial model. In this paper, we propose a set of techniques to allow module replication and their composition in new situations, supporting module reutilization, which has a key impact factor within engineering activities. The proposed techniques rely on keeping the module interface unchanged in order to support the integration of the module in new situations.