A Single-instrument strategy, involves in trading only one instrument and can go both buy or sell. The typical usage is to automate entering into a position under certain condition and exiting the position under another condition, hoping to make a profit from the round trip.
Hedge funds, proprietary trading business in i-bank and individual traders - whoever believe they have some winning strategies...
Strategy parameters controls the strategy behavior. For single-instrument strategies, strategy parameters are organised at a flat level
Stock price fluctuates with market. An ordinary Joe's trading strategy is usually to buy a stock at a price that he thinks it is low enough and sell it when it is high enough. Primitive? but there is nothing wrong with that, as long as his judgement is correct, he can make money.However ordinary Joe is too busy to watch the stock price all time and he has a full time job to do to fund his trading. What he can do is to use this strategy frame work to write a single-instrument strategy. He only needs to specify a price he wants to buy and a price he wants to sell then the platform can do the rest of work for him.
As for a professional trader, the advantage lies in he/she can code a much complicate strategy and apply the strategy to many stocks and leave it to the computer to monitor/trade them.