Examen tic

Sound is a vibrational phenomenon transmitted in the form of waves propagating in a determined elastic medium (commonly the air or the water). When the vibrations are produced arbitrarily, without any rhythmic sequencing, we are talking about noise.

Digital sound is the digital codification of an electric signal that represents a sound wave. Consists of a sequence of binary numbers and is derived from the digital sampling and quantification of the analogue signal that subsequently can be codified or compressed, giving rise to more compact formats (audio compression).

• Sampling: consists of measuring the value of an analogue signal at a specific point in time at regular predetermined intervals.

• Quantification: for each sample, it is assigned a value that will represent the amplitude of that sample

• Sample rate: is the number of times per second that a sample is taken from a sound of the analogue signal to digitalise it. It gives an idea of the quality of the digital sound. A CD-Audio quality sound has a sample rate of 44100 Hz (44100 samples per second)

 • Channels: is the number of points from which the sound is emitted. A mono sound has a single channel, a stereo sound two channels and a 5.1 sound has five channels.

• Sample size (resolution):indicates the amount of information bits that occupies the sample. A standard CD-Audio quality has 16 bits.

• Tone: wave magnitude that tells us the number of complete vibrations (frequency) that take place during 1 second. The measurement unit is the Hertz (Hz).

• Intensity: depends on the magnitude of the vibrations (wave amplitude) of the body that produces them. A sound becomes stronger the greater its amplitude is

• Pitch: quality of the sound that allows us to distinguish between two sounds of the same intensity and tone

1. Linear structure: the navigation works as a book in which the pages are being turned onwards or backwards. This type of pages is recommended for pages of manuals

2. Hierarchical structure: the navigation works by means of category levels of the contents. From each individual page it will be possible to access to the upper level and the home page.

3. Mixed structure: combines the hierarchical navigation with zones of linear navigation. It is the most used.

4. Frame structure: consists of having always visible a side or upper frame with the access menu to the different main sections of the website. Within the same structure can be established hierarchical or linear relationships, but the main menu of the frame must always be present.

5. Web structure: all the pages provide access to the rest of the contents. The navigation can be quite confusing, but offers full freedom of choice to the user.

• Streaming is the possibility of playing multimedia content directly from a web server without the need to download the files to our computer.

• Traditionally, when you wanted to listen to a song or display a video that was hosted on the Internet, it had to be previously downloaded to our local computer in order to be played

• With the new streaming techniques, whose use has proliferated in the Web, this is no longer necessary. Thanks to the bandwidths existing nowadays, it can be assured a continuous data flow that allows playing a video or listening to music in real time.

• Currently, the most of the radio stations and many of the television stations broadcast their contents through Internet.

• In order to incorporate multimedia files into a web page are used different technologies based on players that support streaming, such as Real Player, QuickTime, Windows Media Player or Flash Player.

• The Content Management Systems (CMS) are applications installed on the server that enable us the creation of dynamic web pages and allow us to design the site independently of the content. This way, the changes done in the design do not affect the contents, and vice versa.

• The CMS are modified through Internet, so any administrator can do it from a remote computer.

• When we administer a CMS, we define an aspect in accordance with some PHP templates created by us or facilitated by user communities. These templates work as an empty presentation box into which we have to create the web page by adding articles, news, downloadable files, etc.

• The most of CMS are freely distributable and do not require great knowledge of programming. Another advantage of CMS is their large user communities that, selflessly way, develope new modules or components that extend the possibilities of these applications. The dynamism of these pages lies in the possibility that any user can update them by adding news, downloadable files, content articles, conversations in the forums, etc

• For the creation of a web page we will use a previously mention free web editor. This is the editor Kompozer, that does not require installation, we have just to double-click on its executable file in order to start to work in the programme.

• Kompozer allows the creation of Cascading Style Sheets (CSS). The CSS are some standard configuration files that store information about the attributes of the different types of text that compose a web page. In this way the content (that will be found in the HTML document) and the format (that will be specified in the CSS file) are separated.

• The third practice will consist in the creation of a full website of original theme with, at least, four pages containing multimedia and other elements such as lists, tables, links, etc. following a web structure. As a help it may be used the attached file “Práctica 3 – Kompozer” which explains step by step how to create web sites including the main “index.html” file, tables, layers, links, CSS, insertion of videos and images, etc

• The word chat refers to the Internet service that allows us to keep written conversations instantly with other users of the Net.

• The Chat includes all services able to communicate with two or more users between them in real time. Within the term or chat service we may encompass real time conversations being offered through instant messaging, the use of client chat programs like ChatZilla or the use of Webchat (windows in a web page in which to read or write messages).

• Prominent amongst specific chat applications are X-Chat, ChatZilla or mIRC, that use the Internet protocol IRC (Internet Relay Chat). For being able to connect with a chat that uses this IRC protocol, we must have the proper client software installed in our computer (i.e. plugins).

• When accessing an IRC chat, we must register in order to use a user name or nickname. There are chats that include webcam utility and allow conversation while video is displayed. They are videochats.

• The Chat is a complementary tool in many other applications. The Web Conference or Webinar is a new communication service focused on teaching, in which a moderator gives a multimedia lecture and creates interactivity with the rest of the participants through voice, video, shared desktop, shared applications and, as we have said, chat.