Adaptive Test Question Buffering to Reduce Latency
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Solution Overview
Problem
Computer adaptive tests (CATs) face significant latency issues due to the need for remote question storage and updating, leading to delays in question presentation and resource wastage from downloading unused questions, while also posing security concerns.
Innovation Solution
Implementing a method where a threshold number of questions are pre-downloaded at the testing terminal, allowing for adaptive selection based on earlier answers without immediate real-time updates, thereby reducing latency and minimizing bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If questions are stored remotely on secure servers and fetched in real-time, then test security is improved, but system latency increases causing delays between questions
Solution Approach 1:
The system pre-loads a buffer of questions (e.g., 5-10 questions) onto the testing terminal before they are needed. This preliminary action ensures that when a question is answered, the next question is already available locally, eliminating the real-time network fetch delay while maintaining security since questions are loaded in advance under controlled conditions
2Loss of time
If decision trees are used to download potential future questions, then latency is reduced, but bandwidth is wasted downloading questions that may not be used
Solution Approach 1:
Instead of using complex decision trees that download multiple potential question paths, the system changes the parameter of question buffering by maintaining a simple fixed-size buffer of pre-loaded questions. This simplifies the download logic to only fetch questions sequentially in advance, dramatically reducing bandwidth consumption while still eliminating latency
3Loss of time
If a buffer of questions is maintained at the terminal, then latency is reduced, but more memory is required locally
Solution Approach 1:
The system applies partial buffering by maintaining a buffer of only 5-10 questions locally rather than caching all possible questions. This partial action is sufficient to eliminate the perceptible latency between questions while keeping the local memory requirement minimal and manageable
Data Source
AI summary
A system and method for administering tests at a computer terminal in communication with a remote location is provided. The method includes: establishing an initial threshold amount of questions, the initial threshold amount being a positive integer greater than one; sending to the computer terminal a first batch of questions that exceeds the threshold amount, the batch of questions having a substantially equal difficulty level; receiving an answer to one of the batch of questions; selecting, based on the answer to the one of the number of questions, a new question having a difficultly level different than the one of the number of questions; and sending the new question to the computer terminal.