Stochastic Database Cracking: Towards Robust Adaptive Indexing in Main-Memory Column-Stores

Modern business applications and scientific databases call for inherently dynamic data storage environments. Such environments are characterized by two challenging features: (a) they have little idle system time to devote on physical design; and (b) there is little, if any, a priori workload knowledge, while the query and data workload keeps changing dynamically. In such environments, traditional approaches to index building and maintenance cannot apply. Database cracking has been proposed as a solution that allows on-the-fly physical data reorganization, as a collateral effect of query processing. Cracking aims to continuously and automatically adapt indexes to the workload at hand, without human intervention. Indexes are built incrementally, adaptively, and on demand. Nevertheless, as we show, existing adaptive indexing methods fail to deliver workload-robustness; they perform much better with random workloads than with others. This frailty derives from the inelasticity with which these approaches interpret each query as a hint on how data should be stored. Current cracking schemes blindly reorganize the data within each query's range, even if that results into successive expensive operations with minimal indexing benefit. In this paper, we introduce stochastic cracking, a significantly more resilient approach to adaptive indexing. Stochastic cracking also uses each query as a hint on how to reorganize data, but not blindly so; it gains resilience and avoids performance bottlenecks by deliberately applying certain arbitrary choices in its decision-making. Thereby, we bring adaptive indexing forward to a mature formulation that confers the workload-robustness previous approaches lacked. Our extensive experimental study verifies that stochastic cracking maintains the desired properties of original database cracking while at the same time it performs well with diverse realistic workloads.Comment: VLDB201

Health System Reform: The Value and Price of Innovation

Explores the role of innovation in healthcare by reviewing the literature on international, federal, state, and local examples of system change; barriers to change; the contributions of research, academia, and industry; and the financing of innovation

Managed Forgetting to Support Information Management and Knowledge Work

Trends like digital transformation even intensify the already overwhelming mass of information knowledge workers face in their daily life. To counter this, we have been investigating knowledge work and information management support measures inspired by human forgetting. In this paper, we give an overview of solutions we have found during the last five years as well as challenges that still need to be tackled. Additionally, we share experiences gained with the prototype of a first forgetful information system used 24/7 in our daily work for the last three years. We also address the untapped potential of more explicated user context as well as features inspired by Memory Inhibition, which is our current focus of research.Comment: 10 pages, 2 figures, preprint, final version to appear in KI - K\"unstliche Intelligenz, Special Issue: Intentional Forgettin

Fixing a Flat at 65 MPH: Restructuring Services to Improve Program Performance in Workforce Development

Business leaders have easy access to primers on organizational change; indeed many are bestsellers. In contrast, little is available to nonprofit executives intent on restructuring their organizations. And, while many lessons from the business world are relevant, there are unique aspects of nonprofits' missions and organizational cultures that demand special attention. This report examines the restructuring of three leading workforce development organizations that were seeking to improve performance. Based on their many achievements and the occasional misstep, Fixing a Flat at 65 MPH offers nonprofit managers seven guiding principles addressing the most significant challenges likely to arise during a major reorganization

Analyst Ratings for Firms Filing and Reorganizing Under Chapter 11

Purpose The purpose of this paper is to examine analyst followings of firms starting from one year prior to their filing for Chapter 11 and as the firms progress through bankruptcy proceedings with a focus on firms receiving “Hold” or better recommendations. The authors attempt to answer questions such as what the common characteristics of the firms receiving stronger than expected recommendations one year prior to filing for bankruptcy reorganization or while in bankruptcy are, and how the market reacts to the issuance of stronger ratings for those firms. Design/methodology/approach The authors design various regressions and apply them to a total of 2,754 sell-side analyst recommendations and 325 firms that are either approaching bankruptcy filing or in the process of reorganizing. In each analysis, the authors control for several firm and performance characteristics. Findings The authors find that the probability of securing stronger ratings is higher for small firms and for those followed by a greater number of analysts than for large firms and firms followed by fewer analysts. The market becomes more skeptical of optimistic evaluations closer to the date of bankruptcy filing (perhaps reflecting some anticipation) and reacts more positively to rating upgrades issued during bankruptcy protection than to the upgrades issued before the bankruptcy filing. Research limitations/implications The conclusions are based on the analysis of analyst recommendations issued shortly before Chapter 11 filings and during bankruptcy proceedings. The conclusions could be strengthened by further analysis of firms’ post-bankruptcy recovery and performance and examination of analyst recommendations issued for the firms after they emerge from Chapter 11.. Practical implications Analyst security ratings that are more positive than expected are perhaps the result of superior expertise and access to private information. During bankruptcy proceedings, when information disclosure is limited, investors could greatly benefit from reports issued by security analysts. Originality/value This study contributes to the literature in a number of ways. First, the authors contribute to the literature on the analyst ratings of firms in distress by considering the period between bankruptcy filing and emergence, while the existing literature provides analysis of pre-bankruptcy recommendations and forecasts. Second, the authors focus on better than expected ratings rather than all types of ratings as the firms approach bankruptcy filings and proceed through reorganization. Finally, they evaluate how investors react to stronger than expected analyst ratings

Are interventions for improving the quality of services provided by specialized drug shops effective in sub-Saharan Africa? A systematic review of the literature.

PURPOSE: We set out to determine effectiveness of interventions for improving the quality of services provided by specialized drug shops in sub-Saharan Africa. DATA SOURCES: We searched PubMed, CAB Abstracts, Web of Science, PsycINFO and Eldis databases and websites for organizations such as WHO and Management Sciences for Health. Finally, we searched manually through the references of retrieved articles. STUDY SELECTION: Our search strategy included randomized trials, time-series studies and before and after studies evaluating six interventions; education, peer review, reorganizing administrative structures, incentives, regulation and legislation. DATA EXTRACTION: We extracted information on design features, participants, interventions and outcomes assessed studies for methodological quality, and extracted results, all using uniform checklists. RESULTS OF DATA SYNTHESIS: We obtained 10 studies, all implementing educational interventions. Outcome measures were heterogeneous and included knowledge, communication and dispensing practices. Education improved knowledge across studies, but gave mixed results on communication between sellers and clients, dispensing of appropriate treatments and referring of patients to health facilities. Profit incentives appeared to constrain behaviour change in certain instances, although cases of shops adopting practices at the expense of sales revenue were also reported. CONCLUSION: Evidence suggests that knowledge and practices of pharmacies and drug shops can be improved across a range of diseases and countries/regions, although variations were reported across studies. Profit incentives appear to bear some influence on the level of success of interventions. More work is required to extend the geographical base of evidence, investigate cost-effectiveness and evaluate sustainability of interventions over periods longer than 1 year