The paper presents a novel method for compressing large database workloads for purpose of autonomic, continuous index selection. The compressed workload contains a small subset of representative queries from the original workload. A single pass clustering algorithm with a simple and elegant selectivity based query distance metric guarantees low memory and time complexity. Experiments on two rea...

In the design of a relational database, the administrator has to decide, given a fixed or estimated workload, which indexes should be created. This so called index selection problem is an non-trivial optimization problem in relational databases. In this paper we describe a novel approach for index selection on RDF data sets. We propose an algorithm to automatically suggest a set of indexes as m...

To contribute to systems that reason about human attention, our work empirically demonstrates how a user’s mental workload changes during task execution. We conducted a study where users performed interactive, hierarchical tasks while mental workload was measured through the use of pupil size. Results show that (i) different types of subtasks impose different mental workload, (ii) workload decr...

Extensive job stress and workload are main causes of frustration and reduced efficiency among workers and despite negative effects of these factors on employees' performance, related studies in rehabilitation staff are limited. The aim of this study was to evaluate job stress, workload and their related factors in rehabilitation staff. In this cross-sectional study, 150 employees in three rehab...

AIM To calculate workloads of Departments of Pathology and staff histopathologists at two Croatian University Hospitals by means of the Suvarna and Kay's Kim Unit (KU) activity index. METHOD The total number of specimens and KU activity/year were calculated to compare staff pathologists' workload in two Pathology Departments, one at Split and the other at Zagreb University Hospital. The indiv...

mental workload is one of the factors that influence individuals’ performance in the work environment as well as their efficiency and productivity. the present study aimed at examining the association between mental workload and general health among welders of tehran heavy structuress metal company.this cross-sectional study was conducted in 2016. the sample included 100 welders who were workin...

background: the lack of satisfaction and balance between the workload and abilities and limitations of individuals in various occupations may influence their general health. the aim of this study was to determine the effect of workload and job satisfaction on the general health of industrial workers.   materials and methods: this was a cross-sectional and correlational study on 215 workers of a...

Index tuning, i.e., selecting the indexes appropriate for a workload, is a crucial problem in database system tuning. In this paper, we solve index tuning for large problem instances that are common in practice, e.g., thousands of queries in the workload, thousands of candidate indexes and several hard and soft constraints. Our work is the first to reveal that the index tuning problem has a wel...

Several indexing techniques have been proposed to accelerate database operations in object-oriented databases. A database operation gives rise to the processing of a path. We address the problem of optimal index connguration for a given logical schema, the workload deened on the schema and some other database characteristics such as the cardinality of a class, page size, etc. As will be shown a...

Electroencephalography (EEG) is an important physiological index of cognitive workload. While previous research has employed high-end EEG devices, this work investigates the feasibility of measuring cognitive workload with a low-cost EEG system. In our experiment, EEG signals are recorded from subjects performing silent reading tasks under different difficulty levels. Experimental results demon...