Act as a senior academic researcher with 10+ years of experience in educational technology and AI applications. Analyze the role of AI in detecting academic plagiarism by comparing [THREE SPECIFIC AI TOOLS] (e.g., Turnitin, Grammarly, Copyscape) across [THREE METRICS] (e.g., accuracy, speed, cost-effectiveness) for [THREE DIFFERENT ACADEMIC LEVELS] (e.g., high school, undergraduate, postgraduate). Include a discussion on how AI handles [PARAPHRASED CONTENT] versus [DIRECT COPIES], and propose [THREE IMPROVEMENTS] for future AI plagiarism detectors. Support your analysis with [CASE STUDIES OR RESEARCH DATA] where possible, and conclude with ethical considerations regarding [STUDENT PRIVACY] and [FALSE POSITIVES].