Change the text into Academic Style?

The research objects of this study are as follow: first, develop a numerical representation method, a computational language model, for design text so that sentiment and subject matter can be detected by a machine learning system. Secondly, build a corpus of design text for training and validation purposes for a supervised machine learning system, Fourthly, construct a large database to calculate word orientation based on a word's co-occurrence with a canonical set of positive and negative words in a text-based very large database. Fifthly, compare the complexity of the proposed approach to the complexity of established methods. Finally, compare the computational complexity of the text representation to a bag-of-words representation.

The research objects of this study are as follows. First, develop a numerical representation method, a computational language model, for design text so that sentiment and subject matter can be detected by a machine learning system. Second, build a corpus of design text for training and validation purposes for a supervised machine learning system, Fourth, construct a large database to calculate word orientation based on a word's co-occurrence with a canonical set of positive and negative words in a very large text-based database. Fifth, compare the complexity of the proposed approach to the complexity of established methods. Finally, compare the computational complexity of the text representation to a bag-of-words representation.

Don't use the colon because you are not listing all five in the part of the sentence that follows the colon.

Be consistent. First/second/third/etc. or   firstly/secondly/thirdly/etc. The former is simpler and commonly used

Clive