An Empirical Validation of Oracle Improvement Jahangirova, Gunel; Clark, David; Harman, Mark ...
IEEE transactions on software engineering,
08/2021, Volume:
47, Issue:
8
Journal Article
Peer reviewed
Open access
We propose a human-in-the-loop approach for oracle improvement and analyse whether the proposed oracle improvement process is helping developers to create better oracles. For this, we conducted two ...human studies with 68 participants overall: an oracle assessment study and an oracle improvement study. Our results show that developers exhibit poor performance (29 percent accuracy) when manually assessing whether an assertion oracle contains a false positive, a false negative or none of the two. This shows that automated detection of these oracle deficiencies is beneficial for the users. Our tool OASIs ( O racle AS sessment and I mprovement) helps developers produce assertions with higher quality. Participants who used OASIs in the improvement study were able to achieve 33 percent of full and 67 percent of partial correctness as opposed to participants without the tool who achieved only 21 percent of full and 43 percent of partial correctness.
Motivation: The availability of user-friendly, high-resolution global environmental datasets is crucial for bioclimatic modelling. For terrestrial environments, WorldClim has served this purpose ...since 2005, but equivalent marine data only became available in 2012, with pioneer initiatives like Bio-ORACLE providing data layers for several ecologically relevant variables. Currently, the available marine data packages have not yet been updated to the most recent Intergovernmental Panel on Climate Change (IPCC) predictions nor to present times, and are mostly restricted to the top surface layer of the oceans, precluding the modelling of a large fraction of the benthic diversity that inhabits deeper habitats. To address this gap, we present a significant update of Bio-ORACLE for new future climate scenarios, present-day conditions and benthic layers (near sea bottom). The reliability of data layers was assessed using a cross-validation framework against in situ quality-controlled data. This test showed a generally good agreement between our data layers and the global climatic patterns. We also provide a package of functions in the R software environment (sdmpredictors) to facilitate listing, extraction and management of data layers and allow easy integration with the available pipelines for bioclimatic modelling. Main types of variable contained: Surface and benthic layers for water temperature, salinity, nutrients, chlorophyll, sea ice, current velocity, phytoplankton, primary productivity, iron and light at bottom. Spatial location and grain: Global at 5 arcmin (c. 0.08° or 9.2 km at the equator). Time period and grain: Present (2000–2014) and future (2040–2050 and 2090–2100) environmental conditions based on monthly averages. Major taxa and level of measurement: Marine biodiversity associated with sea surface and epibenthic habitats. Software format: ASCII and TIFF grid formats for geographical information systems and a package of functions developed for R software.
A blockchain provides decentralization and trustlessness features for the Industrial Internet of Things (IIoT), which expands the application scenarios of IIoT. To address the problem that ...blockchains cannot actively obtain off-chain data, the blockchain oracle is proposed as a bridge between the blockchain and external data. However, the existing oracle schemes make it difficult to solve the problem of low quality of service caused by frequent data changes and heterogeneous devices in IIoT, and the current oracle node selection schemes are difficult to balance security and quality of service. To tackle these problems, this paper proposes a secure and reliable oracle scheme that can obtain high-quality off-chain data. Specifically, we first design an oracle node selection algorithm based on a Verifiable Random Function (VRF) and reputation mechanism to securely select high-quality nodes. Second, we propose a data filtering algorithm based on a sliding window to further improve the consistency of the collected data. We verify the security of the proposed scheme through security analysis. The experimental results show that the proposed scheme can effectively select high-quality nodes, reduce data differences, and improve the quality of service of the oracle. In the oracle network with malicious nodes accounting for 10%, the data accuracy rate is increased by about 4%, and the data variance is reduced by about 45% on average.
The lasso is a popular technique for simultaneous estimation and variable selection. Lasso variable selection has been shown to be consistent under certain conditions. In this work we derive a ...necessary condition for the lasso variable selection to be consistent. Consequently, there exist certain scenarios where the lasso is inconsistent for variable selection. We then propose a new version of the lasso, called the adaptive lasso, where adaptive weights are used for penalizing different coefficients in the ℓ
1
penalty. We show that the adaptive lasso enjoys the oracle properties; namely, it performs as well as if the true underlying model were given in advance. Similar to the lasso, the adaptive lasso is shown to be near-minimax optimal. Furthermore, the adaptive lasso can be solved by the same efficient algorithm for solving the lasso. We also discuss the extension of the adaptive lasso in generalized linear models and show that the oracle properties still hold under mild regularity conditions. As a byproduct of our theory, the nonnegative garotte is shown to be consistent for variable selection.
This research paper aims to investigate the current state of process efficiency in Iraqi universities and propose a management information system (MIS) to improve it. A literature review was ...conducted to identify the challenges faced by universities in Iraq, as well as the solutions proposed in the literature. The findings showed that the main challenges in Iraqi universities include a lack of automation, poor data management, and inadequate communication between departments. A comparison was also made between the challenges faced by Iraqi universities and those faced by universities worldwide. To address these challenges, a survey was conducted to gather data from university staff and students. The survey results were analyzed, and the findings were used to design a MIS based on Oracle Application Express (APEX). The proposed system includes a student records management system, a staff management system, and an automated workflow system to improve communication and collaboration between departments. The proposed system was also found to be in line with the regulations and policies of the Ministry of Higher Education in Iraq. The system architecture and database design were also discussed in detail. The results of this research indicate that implementing a MIS using Oracle APEX can significantly improve the process efficiency in Iraqi universities. This can lead to an increase in the quality of education and a reduction in the administrative burden on staff and students.
We define and analyze three mechanisms for getting common knowledge, a posteriori truths about the world, onto a blockchain in a decentralized setting. We show that, when a reasonable economic ...condition is met, these mechanisms are individually rational, incentive compatible, and decide the true outcome of valid oracle queries in both the non-cooperative and cooperative settings. These mechanisms are based upon repeated games with two classes of players: queriers who desire to get common knowledge truths onto the blockchain and a pool of reporters who posses such common knowledge. Presented with a new oracle query, reporters have an opportunity to report the truth in return for a fee provided by the querier. During subsequent oracle queries, the querier has an opportunity to punish any reporters who did not report truthfully during previous rounds. While the set of reporters has the power to cause the oracle to lie, they are incentivized not to do so.
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