Nielsen’s Five Components of Usability

The Spiral Model is a risk-driven software development process model that combines elements of both prototyping and the waterfall model. It is a type of iterative development where the project passes through four phases in each iteration (spiral): determine objectives, identify and resolve risks, develop and test, and plan the next iteration. It emphasizes continuous risk analysis.

Signal detection is the process of identifying potential causal relationships between a drug and an adverse event from large datasets, typically spontaneous reporting systems. It uses statistical methods, known as disproportionality analysis, to find drug-event combinations reported more frequently than expected. A common measure is the Reporting Odds Ratio (ROR), a value greater than one suggesting a potential signal that requires further investigation.

The international standard ISO 9241-11 defines usability as the "extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use." This definition provides a framework for measuring usability by breaking it down into three distinct, quantifiable components, moving beyond purely subjective assessments.

In fair machine learning, impossibility theorems demonstrate that it is mathematically impossible for an algorithm to satisfy multiple, seemingly intuitive fairness criteria simultaneously, except in trivial cases. For example, an algorithm cannot generally satisfy both demographic parity (equal positive rates across groups) and equalized odds (equal true positive and false positive rates across groups) if the base rates differ between groups.

BFT (acronym of Byzantine Fault Tolerance) is a property of a system that allows it to continue operating correctly and reach consensus even if some of its components fail in arbitrary, unpredictable ways, including malicious behavior (Byzantine failures). This is a much stronger guarantee than tolerating simple crash failures. It requires a minimum of \(3f+1\) total components to tolerate \(f\) faulty, malicious components.

RAID (acronym of Redundant Array of Independent Disks) is a data storage virtualization technology that combines multiple physical disk drives into one or more logical units for data redundancy, performance improvement, or both. Different RAID levels provide varying balances of reliability, availability, performance, and capacity. For example, RAID 1 mirrors data across two disks, while RAID 5 stripes data and parity across at least three disks.

Agile project management is an iterative approach to delivering a project throughout its life cycle. It breaks down large projects into smaller, manageable tasks completed in short iterations or 'sprints.' This allows for frequent reassessment, adaptation of plans, and flexibility in response to change. It prioritizes customer collaboration, working software, and responding to change over comprehensive documentation and rigid plans.

Algorithmic bias mitigation techniques are categorized into three main stages relative to the model training process. Pre-processing methods modify the training data itself (e.g., reweighing, resampling). In-processing methods incorporate fairness constraints directly into the model's learning algorithm. Post-processing methods adjust the model's predictions after they have been made to improve fairness.

Algorithmic confounding occurs when a proxy variable used by an algorithm is correlated with a protected attribute (like race or gender) and also with the outcome of interest. The algorithm may inadvertently learn to discriminate based on the protected attribute by using the proxy, even if the protected attribute itself is explicitly excluded from the model's input data.