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Conducting performance assessment during the early phases of system development enhances early design decisions of system design. The generated performance models from system design will help in identifying the potential performance problems in the system design based on the result of the performance assessment. In recent years, several methods for performance assessment and modeling have been proposed. This paper presents the comparative evaluation of performance assessment and modeling methods to discover the strengths and weaknesses of the existing methods based on a set of criteria which includes process and modeling elements that was developed with the purpose to represent a specific process to assess the performance attributes with the help of modeling concepts. The four selected methods were evaluated based on these criterions and the results will hopefully guidance for developers to propose better methods for performance assessment and modeling in the future.

A real-time system is one in which the temporal aspects of its behaviour are part of their specification. The problem with traditional real-time specification is no guarantees on when and how many deadlines may be missed can be given to the tasks because their specification is focused on met all the deadlines and cannot missed it, otherwise the tasks is totally failed. Thus, the weakly hard specification solve this problem with define a gradation on how the deadlines can be missed while still guaranteeing the tasks meets their deadlines. In this paper, a review has been made on the three specifications of real-time systems which is losses or missed of the deadlines can be permitted occasionally. Three criteria used in the evaluation are the process model, temporal specifications and predictability. These three criteria were chosen because the tasks in real-time systems are usually periodic in nature, have timing constraints like deadlines and the behaviour of the systems must be predictable. The three specifications we reviewed in this paper are the skip constraints known as skip factor s, (m,k)-firm deadlines and the weakly hard constraints. The objective of review is to find which specification is better in order to predict the behaviour of a task based on those three criteria. Based on our review, it is concluded that the weakly hard constraints outperforms the two conventional specifications of weakly hard real-time systems using that three criteria based on our evaluation by using a mobile robot case study due to its capability to specify in a clear of the distribution of deadlines met and missed.

A validation process for integrated model-based methodology for component-based embedded real-time software with a profile is presented in this paper. Unified Modeling Language for Modeling and Analysis Real-Time and Embedded System, as a newly developed profile has been introduced to overcome problems in previous profiles. Nevertheless, a sound and systematic methodology is needed in order to tackle complexity problems that arose. The objective of this paper is to validate the integrated profile and a selected component-based methodology component model for satisfying embedded real-time software requirements, thus helping engineers to model their system, enhancing the structure and component modeling. For that, this paper described a component model meta-model validation process using quality matching for the integration process, involving a profile and a methodology. Nevertheless, this paper focused more towards the validation of the integrated component model before can be implemented on Embedded Real-Time software development, whereby the proposed integration component model is applied on a case study to show its enhancements. The integration result will support to solve complexity whereby the profile is used to solve the lack of specific modeling language notation for embedded real-time system and the method can provide a systematical software process.

The increasing use and reliance on Distributed Embedded Real-Time Systems (DERTS) demand the enhancement of their capabilities. This along with the unique characteristics of DERTS, such as resource constraints, make the design and development more complex. State-of-the-art software development methods like Service-Oriented Computing (SOC) and Model-Driven Development can be used to cope with these complexities. However, both of the methods require the system to be designed at a higher level of abstraction and the details are provided at lower levels. Such design models for DERTS with different levels of abstractions are still currently unavailable. This paper presents four basic design models representing different levels of abstraction, to be used in Service-Oriented DERTS design. The proposed models were applied in the Home Automation domain for verification purposes. This level-by-level modelling does not only simplify the design process, but can also be used as part of a Service-Oriented modelling framework for DERTS. Furthermore, these design models can support service composition during Service-Oriented DERTS development. The service composition modelling would be beneficial for CASE tools development in supporting designers working at different levels of abstraction.