It's actually very simple. Please note that citing your own work is NOT plagiarism, if you remember to correctly cite your own work. Since you have previously written the material that you are citing, you will have no trouble at all in finding your own references, and including them in your citations and References list.

It is a real issue and many researchers face this difficulty. An author can cite their own publications in a journal article or conference paper or book chapter etc. However, it is not a good practice to cite an article in a thesis if the same article is made from that thesis work. You might have cited several references in the published article which you can cite in the thesis since both the works are same.

When an author checks plagiarism for thesis, it will certainly highlight all the portions of his previously published articles based on the thesis work and available online. Because, many researchers use the same sentences in the thesis. We use Turnitin software for plagiarism checking. It will give a report of overall similarity index as well as break up of those similarity index to individual sources. One needs to subtract the similarity from his own publications to the total similarity for thesis.

Please refer the attached image. It shows a partial view of the similarity report for one of my articles. The total similarity is 17% and it shows 4% and 1% from my earlier articles. If it is for thesis, the net similarity will be 17-4-1=12%.

Some universities across the globe follow a different system of thesis submission for Ph.D work. The scholar is required to write an introduction, literature survey and conclusion chapters and append all his publications from the doctoral work. Their will not be any running chapters between literature survey and conclusion. This will completely solve the issue.

Please see the following discussion

https://www.researchgate.net/post/Does_copy_pasting_of_published_research_work_in_PhD_thesis_comes_under_self_plagiarism2

With best regards

Chitra

Basically, each researcher has an urge to produce a good thesis which will make a justice to his / her hard-work during the PhD period and at the same time no question should arise from it in future.

Thank you all for your valuable suggestions. I have seen plagiarism reports sent by IEEE conferences similar to that provided by Dr. Isaac Dinaharan. If in case of PhD thesis, it is a common practice to eliminate the self plagiarism percentage from the total, then it is fine and the problem is solved. The same has been suggested by Dr. Ian Kennedy. I have also gone through the discussion raised from a similar question of Dr. Elangbam Chitra Devi which is very informative.

Thank you all again.

To make myself quite clear. There is no need to self-plagiarise. Merely self-cite, and all is well.

One advice is, try to write them by a different way to avoid the self-plagiarism. The plagiarism detection software read the similarities that suspected to be plagiarism whether self or not, they are the same in the program.

Publishing from a thesis before the defense is a normal issue, and it is also a prerequisite by many institutions for the award of a postgraduate degree. In my faculty, we exclude self-plagiarism in articles derived from a thesis before its defense.

Thank you Dr.s, Ian Kennedy, Abdallah Hussien Fathy and Mohamed EL-Shimy for your kind suggestions and advice. I can understand that copy-paste like thing is a bad practice and will hamper the logical flow of writing a thesis. My only concern was the algorithms and few figures (most of the figures have been reproduced), as I had written in my first post. As from the discussion over here, it is clear that self citation will solve those, I am happy and satisfied. Thank you all for your contributions.