Pursue Some Path : Green Space as a Self-care Method

This action research begins with an exploration of “Green Space,” a theory that claims nature has a deep and meaningful impact on the psyche. Green Space has been shown to help reduce anxiety and increase attention, creativity, and memory. The Transactional Theory Framework is examined in tandem with Green Space theory. The transactional theory is a means to evaluate the processes of coping with stress and stressful events. I applied the concept of Green Space as a primary self-care method and then collected and analyzed data. I looked at how Green Space combats stress and burnout. Additionally, I explored in what ways Green Space impacts my work as an American Sign Language/ English interpreter. I did this by viewing and/or participating in a Green Space event, collecting data via daily journaling, as well as writing pre and post journal entries, and creating work sample

ANTICIPATING THE MNEMONIC SHIFT: ORGANIZATIONAL REMEMBERING AND FORGETTING IN 2001

Following a review of prior work, the paper presents a model of organizational memory. Relying on structuration theory for its development, the model overcomes some of the problematic dualisms of conventional approaches (i.e., subjecUobject, social/technical, abstract/concrete). According to the model, co-memory (for collective memory) consists of rules and resources that recursively mediate both interactivity and structure in organizations. The model provides the basis for a taxonomy of existing and projected IT-based co-memory systems. Four classes of co-memory systems are described: transactional, managerial, strategic, and team. An analysis of driving trends concerning people, structure, and technology is used to project four scenarios for organizations in 2001: bureaucracy, factory, affiliation, and infocracy. Co-memory systems that can be expected in each scenario are discussed. Predictions indicate that a mnemonic s

Privatization-Safe Transactional Memories

Transactional memory (TM) facilitates the development of concurrent applications by letting the programmer designate certain code blocks as atomic. Programmers using a TM often would like to access the same data both inside and outside transactions, and would prefer their programs to have a strongly atomic semantics, which allows transactions to be viewed as executing atomically with respect to non-transactional accesses. Since guaranteeing such semantics for arbitrary programs is prohibitively expensive, researchers have suggested guaranteeing it only for certain data-race free (DRF) programs, particularly those that follow the privatization idiom: from some point on, threads agree that a given object can be accessed non-transactionally. In this paper we show that a variant of Transactional DRF (TDRF) by Dalessandro et al. is appropriate for a class of privatization-safe TMs, which allow using privatization idioms. We prove that, if such a TM satisfies a condition we call privatization-safe opacity and a program using the TM is TDRF under strongly atomic semantics, then the program indeed has such semantics. We also present a method for proving privatization-safe opacity that reduces proving this generalization to proving the usual opacity, and apply the method to a TM based on two-phase locking and a privatization-safe version of TL2. Finally, we establish the inherent cost of privatization-safety: we prove that a TM cannot be progressive and have invisible reads if it guarantees strongly atomic semantics for TDRF programs

The Transactional Conflict Problem

The transactional conflict problem arises in transactional systems whenever two or more concurrent transactions clash on a data item. While the standard solution to such conflicts is to immediately abort one of the transactions, some practical systems consider the alternative of delaying conflict resolution for a short interval, which may allow one of the transactions to commit. The challenge in the transactional conflict problem is to choose the optimal length of this delay interval so as to minimize the overall running time penalty for the conflicting transactions. In this paper, we propose a family of optimal online algorithms for the transactional conflict problem. Specifically, we consider variants of this problem which arise in different implementations of transactional systems, namely "requestor wins" and "requestor aborts" implementations: in the former, the recipient of a coherence request is aborted, whereas in the latter, it is the requestor which has to abort. Both strategies are implemented by real systems. We show that the requestor aborts case can be reduced to a classic instance of the ski rental problem, while the requestor wins case leads to a new version of this classical problem, for which we derive optimal deterministic and randomized algorithms. Moreover, we prove that, under a simplified adversarial model, our algorithms are constant-competitive with the offline optimum in terms of throughput. We validate our algorithmic results empirically through a hardware simulation of hardware transactional memory (HTM), showing that our algorithms can lead to non-trivial performance improvements for classic concurrent data structures

Inherent Limitations of Hybrid Transactional Memory

Several Hybrid Transactional Memory (HyTM) schemes have recently been proposed to complement the fast, but best-effort, nature of Hardware Transactional Memory (HTM) with a slow, reliable software backup. However, the fundamental limitations of building a HyTM with nontrivial concurrency between hardware and software transactions are still not well understood. In this paper, we propose a general model for HyTM implementations, which captures the ability of hardware transactions to buffer memory accesses, and allows us to formally quantify and analyze the amount of overhead (instrumentation) of a HyTM scheme. We prove the following: (1) it is impossible to build a strictly serializable HyTM implementation that has both uninstrumented reads and writes, even for weak progress guarantees, and (2) under reasonable assumptions, in any opaque progressive HyTM, a hardware transaction must incur instrumentation costs linear in the size of its data set. We further provide two upper bound implementations whose instrumentation costs are optimal with respect to their progress guarantees. In sum, this paper captures for the first time an inherent trade-off between the degree of concurrency a HyTM provides between hardware and software transactions, and the amount of instrumentation overhead the implementation must incur