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You possess a dataset that monitors the locations of ships, with each position documented as a tuple consisting of (ship_ID, x, y, z, timestamp). Due to the inconsistent timing of the timestamps, potentially caused by sensor errors or disruptions, create a system that can detect ships that stray from their intended path.

Approach / Explanation

The scenario described involves tracking and recording the positions of ships in a dataset that includes the following details: ship_ID, x, y, z, and timestamp. However, the timestamps are inconsistent and uneven, which may complicate real-time or periodic analysis. Your objective is to create a system that can identify when each ship diverges from its intended path or course. To effectively tackle this, you should break the problem into the following essential elements: Data management - A solution is needed to manage and process data with irregular intervals. Identifying or monitoring the usual route – There must be a way to recognize the typical path or pattern that each ship generally follows. Detection of course deviation – The system needs a method to identify when a ship veers off its normal course. Notification system - Once a deviation is identified, there should be a mechanism to inform the relevant parties about this change. Keep in mind that while you don’t need to delve deeply into coding specifics, demonstrating an understanding of the technical aspects of each component will reflect your grasp of the overall system.

Suggested Answer

Approach: I would develop a system that incorporates a time-sensitive machine learning model (such as LSTM) capable of managing irregular time intervals. Initially, our system should preprocess the data obtained from sensors to address missing information or irregular time intervals. Techniques like interpolation or statistical methods can be employed to fill in missing data or to manage irregularities. Subsequently, we need to define a standard route for each vessel. By utilizing previously recorded positions and machine learning models, we can establish a typical course for each ship, which can adapt to changes in the route over time. After identifying the usual route, we must implement a method for detecting deviations. This can be achieved by calculating the Euclidean distance between the estimated position (based on the usual course) and the actual position at each time stamp. If this distance surpasses a predetermined threshold, it will be flagged as a deviation from the course. Finally, an alert system will be established to inform stakeholders whenever a ship strays from its designated route. This could be a straightforward messaging service or even a dashboard that visualizes the ship's movements and any deviations.

Alternative Answer

Design Option: The proposed design model may utilize a blend of time-series analysis and clustering techniques to manage irregular time intervals and pinpoint course deviations. Data preprocessing will focus on addressing irregular time intervals. Time-series decomposition can be applied to tackle this issue, enabling the extraction and analysis of trends and patterns despite the inconsistencies. To monitor the standard route of each ship, I recommend clustering the GPS coordinates (x,y,z) of each vessel. Clustering algorithms such as DBSCAN are adept at handling spatial data and can establish a typical route for every ship. To identify course deviations, new incoming position data should be compared against the clusters created in the previous step. If the new position data lies outside these clusters, it may indicate a deviation from the usual course. Lastly, an alert system can be implemented to send notifications whenever a deviation is detected. The system should be designed to communicate alerts clearly and informatively to the relevant stakeholders.

Question Details

Difficulty & Category

Medium
system design

Companies

SAP

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