Creative Aging in America's Libraries: Year Two Evaluation Report

Creative Aging in America's Libraries is a three-year national leadership initiative to improve, expand and sustain Creative Aging programming in public libraries. It was designed and is led by Lifetime Arts, Inc., in partnership with Westchester Library System. Major support is provided by the Institute for Museum and Library Services. Twenty library systems across the country (listed in Appendix A) are participating in this initiative. The initiative began in the spring of 2014 with a preparation phase, equipping participating libraries to plan and conduct instructional arts programs for older adults according to the model developed by Lifetime Arts. Activities included a series of webinars; a pair of three-day regional training institutes (one in the east, one in the west) to which each library system sent a team of up to five librarians and administrators; launch of a Wikispace where participants can raise questions, exchange information and engage in peer learning and mutual support; access to Lifetime Arts' online resources; and customized assistance from Lifetime Arts staff. The second phase, implementation, began in late 2014 and runs through mid-2016. During this phase, each system is conducting between two and five Creative Aging programs, with support from Lifetime Arts. Goals are to demonstrate and evaluate the model including testing any local variations, build capacity, and begin building sustainability for this kind of programming. Altogether, 67 Creative Aging programs are planned across the 20 systems (plus additional programs in several systems conducted with funding from other sources). A final phase, from July through December 2016, will analyze final results and lessons from all sites, and do further exploration and planning to sustain and expand libraries' Creative Aging activities into the future

Microgrid - The microthreaded many-core architecture

Traditional processors use the von Neumann execution model, some other processors in the past have used the dataflow execution model. A combination of von Neuman model and dataflow model is also tried in the past and the resultant model is referred as hybrid dataflow execution model. We describe a hybrid dataflow model known as the microthreading. It provides constructs for creation, synchronization and communication between threads in an intermediate language. The microthreading model is an abstract programming and machine model for many-core architecture. A particular instance of this model is named as the microthreaded architecture or the Microgrid. This architecture implements all the concurrency constructs of the microthreading model in the hardware with the management of these constructs in the hardware.Comment: 30 pages, 16 figure

Probabilistic Rely-guarantee Calculus

Jones' rely-guarantee calculus for shared variable concurrency is extended to include probabilistic behaviours. We use an algebraic approach which combines and adapts probabilistic Kleene algebras with concurrent Kleene algebra. Soundness of the algebra is shown relative to a general probabilistic event structure semantics. The main contribution of this paper is a collection of rely-guarantee rules built on top of that semantics. In particular, we show how to obtain bounds on probabilities by deriving rely-guarantee rules within the true-concurrent denotational semantics. The use of these rules is illustrated by a detailed verification of a simple probabilistic concurrent program: a faulty Eratosthenes sieve.Comment: Preprint submitted to TCS-QAP

Relating goal scheduling, precedence, and memory management in and-parallel execution of logic programs

The interactions among three important issues involved in the implementation of logic programs in parallel (goal scheduling, precedence, and memory management) are discussed. A simplified, parallel memory management model and an efficient, load-balancing goal scheduling strategy are presented. It is shown how, for systems which support "don't know" non-determinism, special care has to be taken during goal scheduling if the space recovery characteristics of sequential systems are to be preserved. A solution based on selecting only "newer" goals for execution is described, and an algorithm is proposed for efficiently maintaining and determining precedence relationships and variable ages across parallel goals. It is argued that the proposed schemes and algorithms make it possible to extend the storage performance of sequential systems to parallel execution without the considerable overhead previously associated with it. The results are applicable to a wide class of parallel and coroutining systems, and they represent an efficient alternative to "all heap" or "spaghetti stack" allocation models

Logical Concurrency Control from Sequential Proofs

We are interested in identifying and enforcing the isolation requirements of a concurrent program, i.e., concurrency control that ensures that the program meets its specification. The thesis of this paper is that this can be done systematically starting from a sequential proof, i.e., a proof of correctness of the program in the absence of concurrent interleavings. We illustrate our thesis by presenting a solution to the problem of making a sequential library thread-safe for concurrent clients. We consider a sequential library annotated with assertions along with a proof that these assertions hold in a sequential execution. We show how we can use the proof to derive concurrency control that ensures that any execution of the library methods, when invoked by concurrent clients, satisfies the same assertions. We also present an extension to guarantee that the library methods are linearizable or atomic