Packet Transactions: High-level Programming for Line-Rate Switches

Many algorithms for congestion control, scheduling, network measurement, active queue management, security, and load balancing require custom processing of packets as they traverse the data plane of a network switch. To run at line rate, these data-plane algorithms must be in hardware. With today's switch hardware, algorithms cannot be changed, nor new algorithms installed, after a switch has been built. This paper shows how to program data-plane algorithms in a high-level language and compile those programs into low-level microcode that can run on emerging programmable line-rate switching chipsets. The key challenge is that these algorithms create and modify algorithmic state. The key idea to achieve line-rate programmability for stateful algorithms is the notion of a packet transaction : a sequential code block that is atomic and isolated from other such code blocks. We have developed this idea in Domino, a C-like imperative language to express data-plane algorithms. We show with many examples that Domino provides a convenient and natural way to express sophisticated data-plane algorithms, and show that these algorithms can be run at line rate with modest estimated die-area overhead.Comment: 16 page

Navigating the Chasms Between Real and Ideal Literacy Professional Development

In this study, we examine the supportive and hindering factors that influenced 26 teachers’ implementation of pedagogy learned through a research-based, resource-intensive literacy PD initiative (100+ hours). Through post-intervention interviews, we explore the space between learning and enactment of new practices for literacy teaching and learning. Specifically, we ask, What are teachers’ perceptions of the contextual factors that support and hinder their moving from learning to implementation of literacy PD? Results indicate four primary supportive factors (PD facilitators, communities of practice, schools/administrators, and student affective responses) and three primary hindering factors (circumstantial factors, lack of resources, and mismatches between school or district demands). Identifying and considering these factors is an important step toward increasing implementation, which serves as a gatekeeper between teacher learning and student outcomes

Raising the Barre and Stretching the Canvas: Implementing High Quality Arts Programming in a National Youth Serving Organization

Experiences of the Boys and Girls Clubs of America suggest that large, multidisciplinary youth organizations can establish high-quality arts program

Planning Graph as a (Dynamic) CSP: Exploiting EBL, DDB and other CSP Search Techniques in Graphplan

This paper reviews the connections between Graphplan's planning-graph and the dynamic constraint satisfaction problem and motivates the need for adapting CSP search techniques to the Graphplan algorithm. It then describes how explanation based learning, dependency directed backtracking, dynamic variable ordering, forward checking, sticky values and random-restart search strategies can be adapted to Graphplan. Empirical results are provided to demonstrate that these augmentations improve Graphplan's performance significantly (up to 1000x speedups) on several benchmark problems. Special attention is paid to the explanation-based learning and dependency directed backtracking techniques as they are empirically found to be most useful in improving the performance of Graphplan

An International Study in Competency Education: Postcards from Abroad

Acknowledging that national borders need not constrain our thinking, we have examined a selection of alternative academic cultures and, in some cases, specific schools, in search of solutions to common challenges we face when we consider reorganizing American schools. A wide range of interviews and e-mail exchanges with international researchers, government officials and school principals has informed this research, which was supplemented with a literature review scanning international reports and journal articles. Providing a comprehensive global inventory of competency-based education is not within the scope of this study, but we are confident that this is a representative sampling. The report that follows first reviews the definition of competency-based learning. A brief lesson in the international vocabulary of competency education is followed by a review of global trends that complement our own efforts to improve performance and increase equitable outcomes. Next, we share an overview of competency education against a backdrop of global education trends (as seen in the international PISA exams), before embarking on an abbreviated world tour. We pause in Finland, British Columbia (Canada), New Zealand and Scotland, with interludes in Sweden, England, Singapore and Shanghai, all of which have embraced practices that can inform the further development of competency education in the United States

Social Skills and Autism Spectrum Disorder

Children on the autistic spectrum display significant social deficits that negatively impact daily functioning and may lead to serious mental health problems. Research on the effectiveness of school based social skills programs and students with Autism Spectrum Disorder (ASD), specifically children identified with Asperger Disorder (AS) and high functioning Autism (HFA), has yielded limited positive outcomes. This study evaluated the effectiveness of a school based social skills program, the Social Skills Improvement System (SSIS), over a 7 month period with six 8th grade middle school students who had been identified with autism or a social disability. Outcome data and program evaluation data were used to identify program modifications and implementation factors needed to adapt this program to meet the unique needs of these adolescents and promote skill generalization. The Social Skills Rating Scale (SSRS) was administered to parents, students, and teachers before and near the end of the intervention. Parent and teacher-completed Social Responsiveness Scales (SRS) were obtained pre- and near the end of the intervention. Program evaluation interviews with teachers, students and parents were conducted during the intervention. Data from these interviews were used to make modifications to the SSIS for the second half of the intervention to facilitate more student involvement and generalization of skills. Program evaluation surveys were completed by parents, teachers, administrators included quantitative and qualitative information were used to provide a better understanding of the meaning of the intervention for each student. Every student demonstrated a positive outcome based on more than one data source. Program evaluation data were used to recommend the SSIS for other middle schools in the district. More studies are needed that incorporate student input and progress monitoring results for adolescents with social disabilities

Caring or not caring for coworkers? An empirical exploration of the dilemma of care allocation in the workplace

Organization and management researchers praise the value of care in the workplace. However, they overlook the conflict between caring for work and for coworkers, which resonates with the dilemma of care allocation highlighted by ethicists of care. Through an in-depth qualitative study of two organizations, we examine how this dilemma is confronted in everyday organizational life. We draw on the concept of boundary work to explain how employees negotiate the boundary of their caring responsibilities in ways that grants or denies care to coworkers. We argue that the possibility of an ethics of care for coworkers requires boundary work that suspends the separation of personal and professional selves and constitutes the worker as a whole person. We contribute to research on care in organizations by showing how care for coworkers may be enabled or undermined by maintaining or suppressing the care allocation dilemma

CRIKEY! ― It's co-ordination in temporal planning

Temporal planning contains aspects of both planning and scheduling. Many temporal planners assume a loose coupling between these two sub-problems in the form of "blackbox" durative actions, where the state of the world is not known during the action's execution. This reduces the size of the search space and so simplifies the temporal planning problem, restricting what can be modelled. In particular, the simplification makes it impossible to model co-ordination, where actions must be executed concurrently to achieve a desired effect. Coordination results from logical and temporal constraints that must both be met, and for this reason, the planner and scheduler must communicate in order to find a valid temporal plan. This communication effectively increases the size of the search space, so must be done intelligently and as little as possible to limit this increase. This thesis contributes a comprehensive analysis of where temporal constraints appear in temporal planning problems. It introduces the notions of minimum and maximum temporal constraints, and with these isolates where the planning and scheduling are coupled together tightly, in the form of co-ordination, it characterises this with the new concepts of envelopes and contents. A new temporal planner written, called СRIKЕҮ, uses this theory to solve temporal problems involving co-ordination that other planners are unable to solve. However, it does this intelligently, using this theory to minimise the communication between the sub-solvers, and so does not expand the search space unnecessarily. The novel search space that CRIKEY uses docs not specify the timings of future events and this allows for the handling of duration inequalities, which again, few other temporal planners are able to solve. Results presented show СRIKЕҮ to be a competitive planner, whilst not making the same simplifying assumptions that other temporal planners make as to the nature of temporal planning problems

Extending classical planning with state constraints: Heuristics and search for optimal planning

We present a principled way of extending a classical AI planning formalism with systems of state constraints, which relate - sometimes determine - the values of variables in each state traversed by the plan. This extension occupies an attractive middle ground between expressivity and complexity. It enables modelling a new range of problems, as well as formulating more efficient models of classical planning problems. An example of the former is planning-based control of networked physical systems - power networks, for example - in which a local, discrete control action can have global effects on continuous quantities, such as altering flows across the entire network. At the same time, our extension remains decidable as long as the satisfiability of sets of state constraints is decidable, including in the presence of numeric state variables, and we demonstrate that effective techniques for cost-optimal planning known in the classical setting - in particular, relaxation-based admissible heuristics - can be adapted to the extended formalism. In this paper, we apply our approach to constraints in the form of linear or non-linear equations over numeric state variables, but the approach is independent of the type of state constraints, as long as there exists a procedure that decides their consistency. The planner and the constraint solver interact through a well-defined, narrow interface, in which the solver requires no specialisation to the planning contextThis work was supported by ARC project DP140104219, “Robust AI Planning for Hybrid Systems”, and in part by ARO grant W911NF1210471 and ONR grant N000141210430