The Price of Safety in an Active Network

Security is a major challenge for "Active Networking," accessible programmability creates numerous opportunities for mischief. The point at which programmability is exposed, e.g., through the loading and execution of code in network elements, must therefore be carefully crafted to ensure security. The SwitchWare active networking research project has studied the architectural implications of various tradeoffs between performance and security. Namespace protection and type safety were achieved with a module loader for active networks, ALIEN, which carefully delineated boundaries for privilege and dynamic updates. ALIEN supports two extensions, the Secure Active Network Environment (SANE), and the Resource Controlled Active Network Environment (RCANE). SANE extends ALIEN's node protection model into a distributed setting, and uses a secure bootstrap to guarantee integrity of the namespace protection system. RCANE provides resource isolation between active network node users, including separate heaps and robust time-division multiplexing of the node. The SANE and RCANE systems show that convincing active network security can be achieved. This paper contributes a measurement-based analysis of the costs of such security with an analysis of each system based on both execution traces and end-to-end behavior

Design space exploration and optimization of path oblivious RAM in secure processors

Keeping user data private is a huge problem both in cloud computing and computation outsourcing. One paradigm to achieve data privacy is to use tamper-resistant processors, inside which users' private data is decrypted and computed upon. These processors need to interact with untrusted external memory. Even if we encrypt all data that leaves the trusted processor, however, the address sequence that goes off-chip may still leak information. To prevent this address leakage, the security community has proposed ORAM (Oblivious RAM). ORAM has mainly been explored in server/file settings which assume a vastly different computation model than secure processors. Not surprisingly, naïvely applying ORAM to a secure processor setting incurs large performance overheads. In this paper, a recent proposal called Path ORAM is studied. We demonstrate techniques to make Path ORAM practical in a secure processor setting. We introduce background eviction schemes to prevent Path ORAM failure and allow for a performance-driven design space exploration. We propose a concept called super blocks to further improve Path ORAM's performance, and also show an efficient integrity verification scheme for Path ORAM. With our optimizations, Path ORAM overhead drops by 41.8%, and SPEC benchmark execution time improves by 52.4% in relation to a baseline configuration. Our work can be used to improve the security level of previous secure processors.National Science Foundation (U.S.). Graduate Research Fellowship Program (Grant 1122374)American Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipUnited States. Defense Advanced Research Projects Agency (Clean-slate design of Resilient, Adaptive, Secure Hosts Contract N66001-10-2-4089

Student Satisfaction and Performance in an Online Teacher Certification Program

The article presents a study which demonstrates the effectiveness of an online post baccalaureate teacher certification program developed by a Wisconsin university. The case method approach employing multiple methods and multiple data sources were used to investigate the degree to which pre-service teachers were prepared to teach. It was concluded that the study supports online delivery as an effective means of teacher preparation, but it was limited in the number of students followed into their first year of teaching

Internal structure of virtual communications in communities of inquiry in higher education: Phases, evolution and participants’ satisfaction

This study investigates the phases of development of synchronous and asynchronous virtual communication produced in a community of inquiry (CoI) by analyzing the internal structure of each intervention in the forum and each chat session to determine the evolution of their social, cognitive and teaching character. It also analyzes the participating higher education students’ satisfaction with the activities, with the professors’ actions, and with themselves. We use a mixed methodology that includes content analysis of the virtual communications by crossing two categorization systems: (1) type of communication according to the model adopted from Garrison, Anderson and Archer (social, cognitive and teaching presence) and (2) phases in the evolution of the communication (initiation, proposal, development, opinion/closing and good-byes). The data are relevant to the students’ satisfaction and grades earned. The results suggest differences in the quantity and content of the communication in each phase and an evolution from social to cognitive elements, ending with social contributions. The students are satisfied with the virtual communications related to both the activities and the professors and evaluate themselves positively

The Impact of Digital Storytelling on Social Agency: Early Experience at an Online University

Digital Storytelling\u27 is a term often used to refer to a number of different types of digital narrative including web-based stories, hypertexts, videoblogs and computer games. This emergent form of creative work has found an outlet in a wide variety of different domains ranging from community social history, to cookbooks, to the classroom. It is the latter domain that provides the focus for this paper, specifically the online classroom at the tertiary level...Early feedback from students suggests that listening to and telling \u27true stories\u27 was a compelling and emotionally-engaging experience, providing an opportunity for \u27transformative reflection\u27 (Lambert 2000). By including multimedia, learners were able to build upon the fundamentals, presenting content in an easy-to-absorb and compelling way. In terms of team assignments students learned to become more effective actors in collaborative work environments

INTERNATIONALIZATION OF BRAZILIAN FRANCHISE CHAINS: A COMPARATIVE STUDY

The primary goal of this paper is to comprehend the fundamental organizational differences between Brazilian franchise chains that only operate in the home market and Brazilian franchise chains that operate internationally. The sample chosen for this study comprehends 96 Brazilian franchises operating in the home market and 67 franchises with international operations; logistic regression was used to analyze data obtained from these sources. Our findings suggest that the development of a brand in international operations can be strategic for certain Brazilian franchise chains; this seems to be, however, a scarce resource for many franchises and it could be developed through international operations. With regard to the fees charged, the outcomes demonstrate that Brazilian franchises with international operations tend to charge lower fees from its franchisees to install new units. Regarding the monitoring and control of franchises, there is evidence that the monitoring capability is one of the determining factors in the development of Brazilian franchises international operations

Performance configurations over time: implications for growth- and profit-oriented strategies

Strategic entrepreneurship can be described as simultaneous opportunity seeking and advantage seeking. Younger firms are generally more flexible and therefore enjoy 'discovery advantages', whereas established firms tend to be resource rich and more experienced and consequently enjoy 'exploitation advantages'. The resulting evolution of the two important performance dimensions 'growth' and 'profitability' by firm age is not well understood. In this paper we integrate several theoretical arguments concerning profit-growth relationships to develop a dynamic model of firm development which suggests different development pathways for young firms. This leads to several unidirectional, competing hypotheses that we examine by studying the profitability-growth configurations of approximately 3,500 small firms and how these configurations evolve over time. We find that for both young and old firms, a focus on achieving above-average profitability and then striving for growth is a more likely path towards achieving sustained above-average performance than is first pursuing strong growth in the hope of building profitability later. In line with our hypothesis we find that younger firms are over-represented as 'Stars' (high on both growth and profitability) and under-represented as 'Poor' (low on both growth and profitability). However, young firms in the 'Star' category are also less likely than their older counterparts to maintain that position. Furthermore, our results indicate that young firms are over-represented not only among 'Stars', but also among growth-orientated firms regardless of the level of profitability. The findings strongly caution against the blind pursuit of growth for young firms, in favor of a thoughtful analysis of how both growth and profitability might be developed by firms. The results also question whether simultaneous high performance in terms of growth and profitability among young firms usually reflects a successful entrepreneurial strategy. The results can also be interpreted as luck on the part of a sub-group of young firms who indiscriminately pursue growth opportunities with varying profit prospects, and in many cases the high growth-profit performance will be short lived