How is writing an article for publications different from writing a thesis or dissertation in terms of ethics and language usage. How does the background to the study look in the case of an article or dissertation?
An article for publication is a manuscript formatted according to a particular journal's formatting standards, whose content is judged acceptable by the editors, following the advice of referees.*
A thesis or dissertation is a manuscript formatted according to a particular university's formatting standards, whose content is judged acceptable by your advisor, following the advice of a committee.
In both cases, the expectations for ethics, language, length, novelty, rigor, formality, background exposition, typesetting, submission processes, approval processes, and so on strongly depend on the specific people who judge whether the manuscript is acceptable, and more broadly on the institutions and research communities to which those people belong.
You should ask them.
*In computer science, substitute "conference", "program committee", and "reviewers" for "journal", "editors", and "referees", respectively.