Embedded Files
Short Answer
1. What is metadata? Give an example of how a piece of metadata could be used to increase the usefulness of an image or document.
Metadata is information about an electronic document or file, like the file name, the size of the file, the level of encryption, and the owner of the file. If you were looking at a classified document you could use metadata to determine the author of the file and the date it was created.
2. What is a model?
A model is the representation of something from real life into a virtual interpretation. This can apply to digital photographs and many other things.
3. What's the difference between a raster image and an ASCII representation of a text document?
A raster image is based on a division into pixels. An ASCII representation of a text document uses one byte per character.
4. What are filename extensions? What are they used for?
Filename extensions are the three letters after the dot in the filename that indicate how a certain file should be interpreted (.gif, .exe, .jpg).
5. What is lossless representation? What is lossy representation? What are the trade-offs in using each representation?
A lossless representation is a representation that allows exactly the same image to be rendered. A lossy representation is one that allows an approximation of the original image to be rendered. A lossy image could be fine if the images are shown quickly like in a movie.
6. What is steganography and what is it used for? Describe in your own words the steganography algorithm used in the
activity.
Steganography is the art of sending secret messages in imperceptible ways. The steganography algorithm in the activity used patterns of even and odd numbers to determine what part of the sequence was out of place.
7. What would you have to do to delete a document from your computer so that it could not possibly be read by anyone else?
You would have to use a special command like "secure empty trash" or software like DBAN that completely erases what is on a disk drive.
8. What is free and open source software? Provide an example.
Free and open source software is software that is not copyrighted as intellectual property, so is available to anyone who wants to use it. An example would be Linux.
Free Response
1. How has retouching become a controversial issue? Give an example.
Retouching has become a controversial issue because it changes the true nature of photographs and is sometimes viewed as deceptive. It can be used to sell products by promising unrealistic results.
2. Would you rather own a camera (or camera phone) with a higher number of megapixels or lower? Explain.
I would rather own a camera with a higher with a higher number of megapixels because this would mean that there are more pixels in the images and it would have better quality.
3. Other than digital images, what might be an example of a computer model? Explain your answer based on the definition of a model.
An example of a computer model could be a simulation that demonstrates a physical process. I have used models like these in various science classes. They represent an actual process, but are not exactly the real thing.
4. The code that implements App Inventor is open source and its impact on education is obvious. Find another example of open source software and describe its positive impact on education, business or society.
Another example of open source software that benefits society is Blender, which provides a way to do 3D visual effects and 3D printing for free. This allows the public to have access to software they might not usually have access to.
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