Yuichiro

When you are adding images to your paper and presentation, you have to be careful not to violate the copyright of the original publisher. There are so many people who cannot site their works with proper references and many experts see this as a serious problem. One solution to this problem is to use creative commons- licensed images. Creative Commons is a global non profit organization that enables sharing and reuse contents by using legal tools. It was found in 2001 and its vision is to help people realize the full potential of the internet. By using creative commons people can protect their own material and also can clarify the purpose of it.

Creative commons is best known for its abundant license. We can categorize the licenses as below. The most strict license is copyright. Actually this is not made by creative commons, but made by law. Copyright is basically no one can perform a piece written by you or make copies of it, even with attribution, unless you the author accepts it. There are many restrictions considering copyrights which strictly restricts us from using items freely. The opposite side of copyright is CC0. CC0 is a license that acknowledges us to use the content freely in certain conditions. One of the conditions is that 70 years after the authors death has to pass. In between copyright and CC0 there are 4 licenses that creative commons had proposed. I would like to explain them below.（Creative Commons.org）

1. Attribution (by) All CC licenses require that others who use your work in any way must give you credit the way you request, but not in a way that suggests you endorse them or their use. If they want to use your work without giving you credit or for endorsement purposes, they must get your permission first.
2. ShareAlike (sa)You let others copy, distribute, display, perform, and modify your work, as long as they distribute any modified work on the same terms. If they want to distribute modified works under other terms, they must get your permission first.
3. NonCommercial (nc)You let others copy, distribute, display, perform, and (unless you have chosen NoDerivatives) modify and use your work for any purpose other than commercially unless they get your permission first.

4.NoDerivatives (nd)You let others copy, distribute, display and perform only original copies of your work. If they want to modify your work, they must get your permission first.