One elegant way to express the desired part of the need is to combine it with the task in a single sentence.
This sentence expresses first the objective, then the action undertaken to reach this objective, thus creating a strong and elegant connection between need and task.
Start by stating the actual situation (what we have) as a direct continuation of the context.
If you feel you must explain recent achievements in much detail — say, in more than one or two paragraphs — consider moving the details to a section titled State of the art (or something similar) after the Introduction, but do provide a brief idea of the actual situation in the Introduction. Emphasize the contrast between the actual and desired situations with such words as but, however, or unfortunately.
To this end, they must emphasize both the motivation for the work and the outcome of it, and they must include just enough evidence to establish the validity of this outcome.
Papers that report experimental work are often structured chronologically in five sections: first, Introduction; then Materials and Methods, Results, and Discussion (together, these three sections make up the paper's body); and finally, Conclusion.
The traditional Results and Discussion sections are best combined because results make little sense to most readers without interpretation.
When reporting and discussing your results, do not force your readers to go through everything you went through in chronological order.
You can similarly prepare your readers for an upcoming division into subsections by introducing a global paragraph between the heading of a section and the heading of its first subsection. Mention these things early in your paragraph, ideally in the first sentence.
This paragraph can contain any information relating to the section as a whole rather than particular subsections, but it should at least announce the subsections, whether explicitly or implicitly. If you use a standard or usual procedure, mention that upfront, too.