Dimitrios Christodoulakis

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This paper presents a secure watermarking method, which provides robustness against a set of attacks. The watermark is embedded into the blue channel of the images in specific locations that guarantee the minimization of the number of bits modified, based on bit similarities that exist between the signature and the cover data. Visual quality measurements(More)
The correlation between developer-oriented and user-oriented software quality measurements (a case study) " Summary This paper presents a case study on the correlation of user-oriented and developer-oriented measurements. Developer-oriented measurements were performed on 46 different software projects. These projects were given to a number of users, in(More)
This paper presents QSUP, a programming environment enhanced with measurement facilities. Its prime aim is to support preserving software quality standards by the programmers. QSUP offers low level information (raw metric data), as well as high level information such as advice in natural language on quality improvement of the project or a particular(More)
Digital watermarking seems to be one of the most promising methods for copyright protection of digital images, authentication, labeling and monitoring. Since digital images can be published in the Internet, anyone can access and manipulate them. Such kind of manipulations (attacks) falls in one of the following categories: (a) those applied without(More)
In this work we p r e s e n t a method for proving copyright o wnership based on Zero Knowledge Interactive Proof (ZKIP) protocols for computation-ally intractable problems. We use the 3-coloring problem, w h i c h consists in assigning one of three available colors to the vertices of a graph so that no two adjacent vertices have the same color. Using the(More)
The widespread use of Internet in conjunction with the appearance of powerful and cheap hardware makes the massive reproduction and distribution of digital material easier than ever before. The digital material is vulnerable to unauthorized modification, duplication and distribution every day. A digitally embedded signature is an identifying characteristic(More)
Web 2.0 has facilitated interactive information sharing on the WWW, allowing users the opportunity to articulate their opinions on different topics. In this framework, certain practices implement information monitoring systems so as digests, reports on keywords and thematic queries regarding opinions on government decisions to be created. Analysis of(More)
Topic: information technology (medical record) Type of session: oral presentation Summary This paper presents a new universal approach for the computer-based patient record, based on the quality requirements for the patient record that rose throughout the years of practice. The expression "computer-based patient record" includes not only the data contained(More)
1 In this work, a method for proving copyright ownership is presented that is based on Zero Knowledge Interactive Proof (ZKIP) protocols for computation-ally intractable problems. The utilized problem is the 3-coloring problem, which consists in assigning one of three available colors to the vertices of a graph so that no two adjacent vertices have the same(More)