3,490 research outputs found

    Security-Driven Software Evolution Using A Model Driven Approach

    Get PDF
    High security level must be guaranteed in applications in order to mitigate risks during the deployment of information systems in open network environments. However, a significant number of legacy systems remain in use which poses security risks to the enterprise’ assets due to the poor technologies used and lack of security concerns when they were in design. Software reengineering is a way out to improve their security levels in a systematic way. Model driven is an approach in which model as defined by its type directs the execution of the process. The aim of this research is to explore how model driven approach can facilitate the software reengineering driven by security demand. The research in this thesis involves the following three phases. Firstly, legacy system understanding is performed using reverse engineering techniques. Task of this phase is to reverse engineer legacy system into UML models, partition the legacy system into subsystems with the help of model slicing technique and detect existing security mechanisms to determine whether or not the provided security in the legacy system satisfies the user’s security objectives. Secondly, security requirements are elicited using risk analysis method. It is the process of analysing key aspects of the legacy systems in terms of security. A new risk assessment method, taking consideration of asset, threat and vulnerability, is proposed and used to elicit the security requirements which will generate the detailed security requirements in the specific format to direct the subsequent security enhancement. Finally, security enhancement for the system is performed using the proposed ontology based security pattern approach. It is the stage that security patterns derived from security expertise and fulfilling the elicited security requirements are selected and integrated in the legacy system models with the help of the proposed security ontology. The proposed approach is evaluated by the selected case study. Based on the analysis, conclusions are drawn and future research is discussed at the end of this thesis. The results show this thesis contributes an effective, reusable and suitable evolution approach for software security

    An Empirical Study of Low-carbon Lifestyle

    Get PDF
    This paper mainly organizes the theory of lifestylefrom the fields of sociology and consumer behavior, it alsooutlines the situation of domestic scholars on the study of thelow-carbon lifestyle. Then this paper does an empiricalresearch, with the method of structural equation, onlow-carbon lifestyle in which residents of Dalian are theobjects of study. And it defines low-carbon lifestyle as asustainable way of life which includes low-carbon publicbehavior, daily low-carbon behavior, social behavior,environmental attitude and low-carbon acknowledgment. Thispaper also finds out that the environmental attitude andlow-carbon acknowledgment affect people’s low-carbonbehavior, includes low-carbon public behavior, social behaviorand daily low0carbon behavior. In the end of the paper, it putsforward the limitations of this study as well as a researchdirection for lifestyle in the future

    Analysis of two stroke marine diesel engine operation including turbocharger cut-out by using a zero-dimensional model

    Get PDF
    In this article, the operation of a large two-stroke marine diesel engine including various cases with turbocharger cut-out was thoroughly investigated by using a modular zero-dimensional engine model built in MATLAB/Simulink environment. The model was developed by using as a basis an in-house modular mean value engine model, in which the existing cylinder block was replaced by a more detailed one that is capable of representing the scavenging ports-cylinder-exhaust valve processes. Simulation of the engine operation at steady state conditions was performed and the derived engine performance parameters were compared with the respective values obtained by the engine shop trials. The investigation of engine operation under turbocharger cut-out conditions in the region from 10% to 50% load was carried out and the influence of turbocharger cut-out on engine performance including the in-cylinder parameters was comprehensively studied. The recommended schedule for the combination of the turbocharger cut-out and blower activation was discussed for the engine operation under part load conditions. Finally, the influence of engine operating strategies on the annual fuel savings, CO2 emissions reduction and blower operating hours for a Panamax container ship operating at slow steaming conditions is presented and discussed
    • …
    corecore