A logic for handling time in temporal databases

In general, databases store current data. However,the capability to maintain temporal data is a crucial requirement for many organizations and provides the base for organizational intelligence. A temporal database maintains time-varying data, that is, past, present, and future data. In this chapter, we focus on the relational data model and address the subtle issues in modeling and designing temporal databases. A common approach to handle temporal data within the traditional relational databases is the addition of time columns to a relation. Though this appears to be a simple and intuitive solution, it does not address many subtle issues peculiar to temporal data, that is, comparing database states at two different time points, capturing the periods for concurrent events and accessing times beyond these periods, handling multi-valued attributes, coalescing and restructuring temporal data, and so forth, [Gadia 1988, Tansel and Tin 1997]. There is a growing interest in temporal databases. A first book dedicated to temporal databases [Tansel at al 1993] followed by others addressing issues in handling time-varying data [Betini, Jajodia and Wang 1988, Date, Darwen and Lorentzos 2002, Snodgrass 1999].

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Managing Temporal Data

Enterprise Information Systems ◽

10.4018/978-1-61692-852-0.ch603 ◽

2011 ◽

pp. 1461-1469

Author(s):

Abdullah Uz Tansel

Keyword(s):

Relational Databases ◽

Handling Time ◽

Current Data ◽

Temporal Databases ◽

Time Varying ◽

Temporal Data ◽

Temporal Database ◽

Organizational Intelligence ◽

Relational Data Model ◽

Future Data

In general, databases store current data. However,the capability to maintain temporal data is a crucial requirement for many organizations and provides the base for organizational intelligence. A temporal database maintains time-varying data, that is, past, present, and future data. In this chapter, we focus on the relational data model and address the subtle issues in modeling and designing temporal databases. A common approach to handle temporal data within the traditional relational databases is the addition of time columns to a relation. Though this appears to be a simple and intuitive solution, it does not address many subtle issues peculiar to temporal data, that is, comparing database states at two different time points, capturing the periods for concurrent events and accessing times beyond these periods, handling multi-valued attributes, coalescing and restructuring temporal data, and so forth, [Gadia 1988, Tansel and Tin 1997]. There is a growing interest in temporal databases. A first book dedicated to temporal databases [Tansel at al 1993] followed by others addressing issues in handling time-varying data [Betini, Jajodia and Wang 1988, Date, Darwen and Lorentzos 2002, Snodgrass 1999].

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The Impact of Live Cases on Student Skill Development in Marketing Courses

Journal of Marketing Education ◽

10.1177/02734753211034553 ◽

2021 ◽

pp. 027347532110345

Author(s):

Shannon Cummins ◽

Jeff S. Johnson

Keyword(s):

Time Management ◽

Learning Experience ◽

Skill Development ◽

Handling Time ◽

Thinking Skills ◽

Critical Thinking Skills ◽

Small Samples ◽

Conflict Handling ◽

Student Skill ◽

The Impact

Live cases, where students work directly with an outside organization to solve real-world problems, can be an immersive learning experience for marketing students. Current scholarship on live case usage in marketing is limited to small samples from a handful of live case devotees. This article draws from a large, international sample of 169 marketing educators to investigate the perceived educational impacts of live cases on student skill development. Specifically, the paper explores student teamwork, conflict handling, time management, presentation, communication, and critical thinking skills. Additionally, the article explores how student skill development is affected by the amount of course time dedicated to the live case as well as faculty experience with live cases.

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Hydraulic insertions of cochlear implant electrode arrays into the human cadaver cochlea: preliminary findings

European Archives of Oto-Rhino-Laryngology ◽

10.1007/s00405-021-06979-z ◽

2021 ◽

Author(s):

M. Geraldine ◽

Thomas Lenarz ◽

Thomas S. Rau

Keyword(s):

Cochlear Implant ◽

Outcome Measurement ◽

Round Window ◽

Handling Time ◽

Human Cadaver ◽

Hydraulic Actuator ◽

Electrode Arrays ◽

Non Invasive ◽

Insertion Tool ◽

Set Up

Abstract Objectives (1) To evaluate the feasibility of a non-invasive, novel, simple insertion tool to perform automated, slow insertions of cochlear implant electrode arrays (EA) into a human cadaver cochlea; (2) to estimate the handling time required by our tool. Methods Basic science study conducted in an experimental OR. Two previously anonymized human cadaver heads, three commercially available EAs, and our novel insertion tool were used for the experiments. Our tool operates as a hydraulic actuator that delivers an EA at continuous velocities slower than manually feasible. Intervention(s): the human cadaver heads were prepared with a round-window approach for CI surgery in a standard fashion. Twelve EA insertion trials using our tool involved: non-invasive fixation of the tool to the head; directing the tool to the round window and EA mounting onto the tool; automated EA insertion at approximately 0.1 mm/s driven by hydraulic actuation. Outcome measurement(s): handling time of the tool; post-insertion cone-beam CT scans to provide intracochlear evaluation of the EA insertions. Results Our insertion tool successfully inserted an EA into the human cadaver cochlea (n = 12) while being attached to the human cadaver head in a non-invasive fashion. Median time to set up the tool was 8.8 (7.2–9.4) min. Conclusion The first insertions into the human cochlea using our novel, simple insertion tool were successful without the need for invasive fixation. The tool requires < 10 min to set up, which is clinically acceptable. Future assessment of intracochlear trauma is needed to support its safety profile for clinical translation.

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Cache-efficient sweeping-based interval joins for extended Allen relation predicates

The VLDB Journal ◽

10.1007/s00778-020-00650-5 ◽

2021 ◽

Author(s):

Danila Piatov ◽

Sven Helmer ◽

Anton Dignös ◽

Fabio Persia

Keyword(s):

Data Structure ◽

Experimental Evaluation ◽

State Of The Art ◽

Temporal Databases ◽

Access Method ◽

Wide Range ◽

Interval Relation ◽

Cache Efficient ◽

Join Algorithms ◽

Better Than

AbstractWe develop a family of efficient plane-sweeping interval join algorithms for evaluating a wide range of interval predicates such as Allen’s relationships and parameterized relationships. Our technique is based on a framework, components of which can be flexibly combined in different manners to support the required interval relation. In temporal databases, our algorithms can exploit a well-known and flexible access method, the Timeline Index, thus expanding the set of operations it supports even further. Additionally, employing a compact data structure, the gapless hash map, we utilize the CPU cache efficiently. In an experimental evaluation, we show that our approach is several times faster and scales better than state-of-the-art techniques, while being much better suited for real-time event processing.

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The effect of research activities and winter precipitation on voiding behaviour of Agassiz’s desert tortoises (Gopherus agassizii)

Wildlife Research ◽

10.1071/wr14196 ◽

2014 ◽

Vol 41 (8) ◽

pp. 641 ◽

Cited By ~ 2

Author(s):

Mickey Agha ◽

Mason O. Murphy ◽

Jeffrey E. Lovich ◽

Joshua R. Ennen ◽

Christian R. Oldham ◽

...

Keyword(s):

Stress Responses ◽

Handling Time ◽

Winter Precipitation ◽

Contact Period ◽

Gopherus Agassizii ◽

Desert Tortoise ◽

Defensive Strategy ◽

Survivorship Analysis ◽

Research Activities

Context There is little information available on how research activities might cause stress responses in wildlife, especially responses of threatened species such as the desert tortoise (Gopherus agassizii). Aims The present study aims to detect behavioural effects of researcher handling and winter precipitation on a natural population of desert tortoises in the desert of Southwestern United States, over the period 1997 to 2014, through extensive assessments of capture events during multiple research studies, and capture–mark–recapture survivorship analysis. Methods Juvenile and adult desert tortoises were repeatedly handled with consistent methodology across 18 years during 10 study seasons. Using a generalised linear mixed-effects model, we assessed the effects of both research manipulation and abiotic conditions on probability of voiding. Additionally, we used a Cormack–Jolly–Seber model to assess the effects of winter precipitation and voiding on long-term apparent survivorship. Key results Of 1008 total capture events, voiding was recorded on 83 (8.2%) occasions in 42 different individuals. Our top models indicated that increases in handling time led to significantly higher probabilities of voiding for juveniles, females and males. Similarly, increases in precipitation resulted in significantly higher probabilities of voiding for juveniles and females, but not for males. Tortoise capture frequency was negatively correlated with voiding occurrence. Cormack–Jolly–Seber models demonstrated a weak effect of winter precipitation on survivorship, but a negligible effect for both voiding behaviour and sex. Conclusions Handling-induced voiding by desert tortoises may occur during common research activities and years of above average winter precipitation. Increased likelihood of voiding in individuals with relatively low numbers of recaptures suggested that tortoises may have perceived researchers initially as predators, and therefore voided as a defensive strategy. Voiding does not appear to impact long-term survivorship in desert tortoises at this site. Implications This study has demonstrated that common handling practices on desert tortoise may cause voiding behaviour. These results suggest that in order to minimise undesirable behavioural responses in studied desert tortoise populations, defined procedures or protocols must be followed by the investigators to reduce contact period to the extent feasible.

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Main Memory-Based Algorithms for Efficient Parallel Aggregation for Temporal Databases

Distributed and Parallel Databases ◽

10.1023/b:dapd.0000028553.70337.e1 ◽

2004 ◽

Vol 16 (2) ◽

pp. 123-163 ◽

Cited By ~ 12

Author(s):

Dengfeng Gao ◽

Jose Alvin G. Gendrano ◽

Bongki Moon ◽

Richard T. Snodgrass ◽

Minseok Park ◽

...

Keyword(s):

Main Memory ◽

Temporal Databases

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Influence of prey size and environmental factors on predation by Podisus maculiventris (Hemiptera: Pentatomidae) on viburnum leaf beetle (Coleoptera: Chrysomelidae)

The Canadian Entomologist ◽

10.4039/n07-021 ◽

2008 ◽

Vol 140 (2) ◽

pp. 192-202 ◽

Cited By ~ 7

Author(s):

Gaylord A. Desurmont ◽

Paul A. Weston

Keyword(s):

Host Plant ◽

Plant Species ◽

Biological Control Agent ◽

Handling Time ◽

Leaf Beetle ◽

Podisus Maculiventris ◽

Viburnum Opulus ◽

Host Plant Species ◽

Search Area ◽

Rate Of Increase

AbstractExperiments were conducted under laboratory conditions to determine the influence of the relative sizes of predator and prey, temperature, presence of refugia, size of the search area, and host-plant species on the predation performance of Podisus maculiventris (Say) nymphs against viburnum leaf beetle, Pyrrhalta viburni (Paykull), a new landscape pest in North America that feeds on the foliage of species of Viburnum L. (Caprifoliaceae). Predator handling time was positively correlated with body mass of the prey for all instars of P. maculiventris, but the rate of increase of handling time relative to prey mass decreased as predator age increased. Temperature was positively correlated with predation rates, but the presence of refugia did not have an impact on predation. The influence of host-plant species and size of the search area was tested on southern arrowwood (Viburnum dentatum L.) and American cranberrybush (Viburnum opulus L. var. americanum Aiton). There was a significant interaction between plant species and size of the search area, the species effect becoming significant as leaf surface area increased. In the case of southern arrowwood a negative correlation between size of the search area and predation rate was also detected. The identification of these factors adds valuable knowledge for using P. maculiventris as a biological-control agent against P. viburni.

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