Currently the 2 percent growth rate for the world's older population exceeds the 1.2 percent rate for the world's population as a whole. This difference is expected to increase rather than diminish so that by 2050, the number of individuals over the age 85 is projected to be three times what it is today. Most of these individuals will need physical, emotional, and cognitive assistance. In this paper, we present a new system based on the socially assistive robotics (SAR) technology that will play the role of a music therapist and will try to provide a customized help protocol through motivation, encouragements, and companionship to users suffering from cognitive changes related to aging and/or Alzheimer's disease.

This research focuses on studying the possible role of a socially interactive robot as a tool for monitoring and encouraging cognitive activities of the elderly and/or individuals suffering from dementia. One of the aims of this work is to show the benefits of the robot's physical embodiment in human-robot social interactions. The social therapist robot tries to provide customized cognitive stimulation by playing a music game with the user. The results of the 8-month pilot study depict a more efficient, natural, and preferred interaction with the robot rather than with the simulated robot.

This paper describes a hands-off therapist robot that monitors, assists, encourages, and socially interacts with post-stroke users in the process of rehabilitation exercises. We developed a behavior adaptation system that takes advantage of the users introversion-extroversion personality trait and the number of exercises performed in order to adjust its social interaction parameters (e.g., interaction distances/proxemics, speed, and vocal content) toward a customized post-stroke rehabilitation therapy. The experimental results demonstrate the robot's autonomous behavior adaptation to the user's personality and the resulting user improvements of the exercise task performance.

We present an approach for implementing language-level primitives for whole-process migration and speculative execution in a compiler and associated runtime environment. These primitives are exposed to the user through simple language constructs that do not require the user to manage process state explicitly. With migration and speculation we show how the user can quickly add persistent checkpoints to any large-scale distributed application that requires longevity in a faulty environment. We demonstrate the use of migration and speculation primitives for checkpointing in a canonical grid computation application, and analyze the results of this implementation.

Model checking, logging, debugging, and checkpointing/recovery are great tools to identify bugs in small sequential programs. The direct application of these techniques to the domain of distributed applications, however, has been less effective (mostly owing to the high degree of concurrency in this context). This paper presents the design of a hybrid tool, FixD, that attempts to address the deficiencies of these tools with respect to their application to distributed systems by using a novel composition of several of these existing techniques. The authors first identify and describe the four abstract components that comprise the FixD tool, then conclude with a proposal for how existing tools can be used to implement these components.

Transactions are a simple and powerful mechanism for establishing fault-tolerance. To allow multiple processes to cooperate in a transaction we relax the isolation property and use message passing for communication. We call the new abstraction a speculation.

This paper presents MojaveFS, a distributed file system with support for sequential consistency. It provides location transparency and makes use of replication for reliability and fault tolerance. We employ a hybrid hash-based and tree-based lookup mechanism for files that, combined with an efficient caching scheme, provides fast access to files in the system. MojaveFS uses a novel data storage strategy where files are split into smaller objects to increase data availability. It also uses a group communication protocol with guarantees for a total order on messages sent within the system, enabling MojaveFS to support the traditional sequential consistency model for concurrent access

This paper presents a kernel level distributed interprocess communication library (KDIPC) with support for distributed shared memory and distributed semaphores. KDIPC uses the System V inter-process communication programming interface and enhances it to provide functionality in distributed environments. A key feature of KDIPC, inherited from System VIPC API, is providing an interface allowing atomic operations on semaphore sets. This permits application developers to perform locking of multiple resources in an atomic manner, simplifies the code and reduces the risk of deadlocks. The implementation is done at the Linux kernel level to reduce the overhead induced by the strict consistency model.

Interprocess communication (IPC) is ubiquitous in today's computing world. One of the simplest mechanisms for IPC is shared memory. We present a system that enhances the System V IPC API to support distributed shared memory (DSM) by using speculations. Speculations provide performance improvements by enabling rollback of overly optimistic speculative executions. This paper describes a speculative total order communication protocol, a speculative sequential consistency model, and a speculative distributed locking mechanism. All these are supported by a mathematical model showing the advantages of speculative execution over traditional execution. Our DSM system is part of the Mojave system, which consists of a compiler and the extensions of the operating system designed to support speculations and process migration. The goal of our system is to provide a simpler programming paradigm for designers of distributed systems.

In this paper, we present the Active Harmony automated runtime tuning system. We describe the interface used by programs to make applications tunable. We present the Library Specification Layer which helps program library developers expose multiple variations of the same API using different algorithms.The Library Specification Language helps to select the most appropriate program library to tune the overall performance. We also present the optimization algorithm used to adjust parameters in the application and the libraries. Finally, we present results that show how the system is able to tune several real applications. The automated tuning system is able to tune the application parameers to within a few percent of the best value after evaluating only 11 out of over 1,700 possible configurations.