You are asked to develop a stock trading software system for your bank. The stock trading works as follows. The users (i.e., the clients) of the system. The bank at a given time contains stocks of number of publicly traded companies. Each such company is identified by an ID in the stock market, each ID is called a ticker. For example, the company Apple has the ticker AAPL in the NASDAQ stock exchange. The bank also monitors a number of tickers on which it has not invested yet, but those tickers are of interest for potential investment to the bank. The system needs to address the following requirements from the clients. 1. The system needs to monitor public sentiments about the tickers the bank has invested in or the ticker the bank is interested in investment. The system monitors public sentiments to tweets and retweets about a ticker in two social networks: X and in Facebook. Two types of sentiments are collected: positive and negative. An aggregator is used to produce the sentiment scores ( 1 for a positive tweet, -1 for a negative tweet) per hour, per day, per week, per month, per year, and overall. The aggregator is