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علوم کامپیوتر برای دبیرستان (CS4MS): چگونه مدیران و معلمان مدارس راهنمایی برنامه های درسی علوم کامپیوتر را اجرا می کنند
Computer Science for Middle School (CS4MS): How Middle School Administrators and Teachers Implement Computer Science Curricula
Computer science education in K-12 schools is a popular topic of study, especially in quantitative research. Many findings concur that computer science education should be introduced at lower grade levels to provide students with early exposure to computing skills or computational thinking more broadly. While there is substantial research about computer science education implementation at the elementary and high school levels. However, there is a paucity of qualitative research about computer science curriculum implementation at the middle school level.
The current case study concentrated on the computer science implementation stories of six teachers and six administrators at six middle schools in a large urban public school district with a large number of socioeconomically disadvantaged and traditionally underrepresented minority students. Through the theoretical framework of diffusion of innovation in organizations, the study investigated the essential elements of a computer science curriculum implementation, as well as the essential elements of sustaining a computer science education implementation. The study also focused on the challenges of computer science education implementation and how the challenges, if any, varied by student population. Lastly, the study sought data on solutions to implementation challenges and how solutions, if any, varied by student population.
Study findings show that when middle school teachers do not receive computer science curriculum training, their implementation of the curriculum does not reach the higher stages of diffusion, such as redefining, clarifying, and routinizing. Results also indicate that the middle school computer science teacher’s dedication to and enthusiasm for teaching the subject is essential to sustaining the implementation. Furthermore, when the administrator and teacher in charge of computer science education are both committed to the implementation, then they are more likely to exhibit a problem-solving mindset.
Challenges to implementing a middle school computer science curriculum include securing funding for training to teach the curriculum, in addition to finding enthusiastic teachers to teach the topic. A further challenge was the lack of teacher support from administrators who were not completely sold on any particular computer science curriculum or plan of implementation. Challenges pertaining to students include teachers not having any assistance with special education students who are not necessarily ready for a computer science classroom environment. Teachers also expressed challenges in terms of student behavior and students’ reluctance to work in teams, especially when there is not enough equipment for every student.
Solutions to the funding challenge that worked for participants of the study included continuous fundraising and grantwriting. Administrators who were more dedicated to implementing computer science education at their middle schools had all read research about the importance of early exposure to computer science opportunities as well as project-based learning curricula. Solutions related to special education students and others who were not ready for the advanced curriculum included having multiple levels of the work available for students to feel challenged at their level.
Teacher enthusiasm and ability to teach CS can be found among existing middle school teachers. Administrators who are informed about middle school CS education are in a better position to make teacher-centered and student-centered decisions about CS implementation. When administrators’ visions of CS implementation align with the middle school teacher’s vision of CS implementation, the social network that is generated by the administrator and CS teacher working collaboratively makes a CS program more sustainable. The alignment of middle school CS education research with existing research about diffusion of innovations makes these insights more accessible. Consequently, the implementation of middle school CS education can be better understood by using the five stages of diffusion of innovations as a theoretical framework.
به سمت دفاع از هدف متحرک سطح شبکه با شبکه سازی تعریف شده نرم افزاری
Towards Network Level Moving Target Defense with Software Defined Networking
Current computer systems are built in a relatively static nature. Once deployed, computer systems will keep running unchanged. They will use the fixed operating systems, a set of fixed software stacks, and the same network configurations, which keep them easy to operate and manage. However, their static nature makes them easy targets of cyber attacks as well. Attackers are able to spend as much time as they can to find an effective way to compromise a target system. Moving Target Defense was proposed as a promising defense paradigm to break the static nature of current computer systems. It tries to introduce uncertainty and unpredictability into computer systems, which can greatly raise the bar for attackers. Software Defined Networking (SDN) is a new network paradigm, which provides unprecedented flexibility and programmability to computer networks. In this dissertation, we propose to achieve a Moving Target Defense at the network level with SDN.
First, we present Sniffer Reflector, a new method to practice Moving Target Defense against network reconnaissance. Network reconnaissance is usually regarded as the very first step of most attacks. The basic idea is to employ SDN programming capability and virtualization technologies to defend against malicious network reconnaissance. We use SDN and network node virtualization technologies to provide an obfuscated reconnaissance result for the attackers. Our experiment results show that Sniffer Reflector is effective and efficient in blurring malicious network reconnaissance.
Then, we propose Shoal, a network-level Moving Target Defense engine over SDN networks. Shoal seeks to build a comprehensive Moving Target Defense engine with multiple MTD strategies over SDN networks. It is designed to fit the need of various security protections and defend against diverse attacks in software defined networks and other virtual network environments. Our experiment shows the effectiveness of Shoal protection and demonstrates it is able to provide complicated protections and mitigate advanced attacks.
Finally, we propose SecControl, a practical security protection framework combining the existing security tools and SDN technologies, to produce a comprehensive network security solution in an SDN network environment. SecControl provides a traditional-security-tool-friendly security solution for SDN networks. Our experiment shows that SecControl can cooperate with many mainstream security tools and provide effective defense responses over SDN-supported networks.