Para responder a questão, leia o texto a seguir.

Body acoustics can turn your arm into a touchscreen

By Paul Marks | March, 2010

Finding the keypad on your cellphone or music player a bit cramped? Maybe your forearm could be more accommodating. It could become part of a skin-based interface that effectively turns your body into a touchscreen.

Bodily interface (Image: ACM)

Called Skinput, the system is a marriage of two technologies: the ability to detect the ultralow-frequency sound produced by tapping the skin with a finger, and the microchip-sized "pico" projectors now found in some cellphones.

The system beams a keyboard or menu onto the user's forearm and hand from a projector housed in an armband. An acoustic detector, also in the armband, then calculates which part of the display you want to activate.

But how does the system know which icon, button or finger you tapped? Chris Harrison at Carnegie Mellon University in Pittsburgh, Pennsylvania, working with Dan Morris and Desney Tan at Microsoft's research lab in Redmond, Washington, exploit the way our skin, musculature and skeleton combine to make distinctive sounds when we tap on different parts of the arm, palm, fingers and thumb.

Bone machine

They have identified various locations on the forearm and hand that produce characteristic acoustic patterns when tapped. The acoustic detector in the armband contains five piezoelectric cantilevers, each weighted to respond to certain bands of sound frequencies. Different combinations of the sensors are activated to differing degrees depending on where the arm is tapped.

Twenty volunteers tested the system and most found it easy to navigate through icons on the forearm and tap fingers to actuate commands.

“Skinput works very well for a series of gestures, even when the body is in motion, “the researchers say, with subjects able to deftly scroll through menus whether they moved up and down or flicked across their arm.

The system could use wireless technology like Bluetooth to transmit commands to many types of device – including phones, iPods and even PCs. The researchers will present their work in April at the ACM Computer- Human Interaction meeting in Atlanta, Georgia.

Body control

Pranav Mistry of the Media Lab at the Massachusetts Institute of Technology warns that users will have to position the armband very precisely so the projection always appears in the right place.

Nevertheless, Skinput looks a promising idea, says Michael Liebschner, director of the Bio-Innovations Lab at Baylor College of Medicine in Houston, Texas, who has worked on bone acoustic conduction technology for gadget-to-gadget transmission.

“This sounds a very feasible approach to using the body itself as an input device," he says. "When you are immersed in a virtual game using a head-mounted 3D display, you cannot just take it off to fiddle around with control buttons. This will make things much easier.”

Fonte: http://www newscientist.com

No segmento “The system could use wireless technology like Bluetooth to transmit commands to many types of device”, a expressão “like” pode ser substituída, sem alteração de sentido, por

Com referência aos efeitos negativos da exposição de um ser humano ao som, marque verdadeira (V) ou falsa (F) em cada afirmativa.

( ) Quanto maior o Nível de Pressão Sonora, menor é o tempo que uma pessoa pode ficar exposta a um som sem que sofra perdas auditivas.

( ) A perda auditiva é irreversível.

( ) A perda auditiva acontece primeiramente nas baixas frequências e, posteriormente, nas altas.

( ) Um trabalhador exposto a altos Níveis de Pressão Sonora durante o dia pode ter problemas de insônia, mesmo que passe o período destinado ao sono em um ambiente silencioso.

A seguir, assinale a alternativa que apresenta a sequência correta.

Destaca-se como uma das características das ondas sonoras que quando duas ondas de mesma frequência se somam, podem sofrer interferência construtiva ou destrutiva. Duas ondas de mesma frequência são mostradas nas Figuras a seguir:

Agora, assinale verdadeira (V) ou falsa (F) em cada afirmativa.

( ) Quando a onda da Figura (A) se soma com a da Figura (B), a onda resultante possui o dobro da amplitude da onda na Figura (A).

( ) Quando a onda da Figura (A) se soma com outra onda como a da Figura (A), a onda resultante possui a mesma amplitude da onda na Figura (A).

( ) Quando a onda da Figura (B) se soma com uma outra onda como a da Figura (B) e uma terceira onda, como a da Figura (A), a onda resultante possui a mesma amplitude da onda na Figura (B).

A sequência correta é

Os microfones são classificados segundo as seguintes categorias: dinâmicos, fita e condensador. Em qual(is) dessas categorias se encontram os microfones mais baratos, mais resistentes e de menor sensibilidade ao mesmo tempo?

O padrão AES/EBU estabelecido em 1985 pela Audio Engineering Society (AES) e pela European Broadcast Union (EBU) serve para a transmissão de que tipo de sinais em tempo real?

Para responder a questão, leia o texto a seguir.

Body acoustics can turn your arm into a touchscreen

By Paul Marks | March, 2010

Finding the keypad on your cellphone or music player a bit cramped? Maybe your forearm could be more accommodating. It could become part of a skin-based interface that effectively turns your body into a touchscreen.

Bodily interface (Image: ACM)

Called Skinput, the system is a marriage of two technologies: the ability to detect the ultralow-frequency sound produced by tapping the skin with a finger, and the microchip-sized "pico" projectors now found in some cellphones.

The system beams a keyboard or menu onto the user's forearm and hand from a projector housed in an armband. An acoustic detector, also in the armband, then calculates which part of the display you want to activate.

But how does the system know which icon, button or finger you tapped? Chris Harrison at Carnegie Mellon University in Pittsburgh, Pennsylvania, working with Dan Morris and Desney Tan at Microsoft's research lab in Redmond, Washington, exploit the way our skin, musculature and skeleton combine to make distinctive sounds when we tap on different parts of the arm, palm, fingers and thumb.

Bone machine

They have identified various locations on the forearm and hand that produce characteristic acoustic patterns when tapped. The acoustic detector in the armband contains five piezoelectric cantilevers, each weighted to respond to certain bands of sound frequencies. Different combinations of the sensors are activated to differing degrees depending on where the arm is tapped.

Twenty volunteers tested the system and most found it easy to navigate through icons on the forearm and tap fingers to actuate commands.

“Skinput works very well for a series of gestures, even when the body is in motion, “the researchers say, with subjects able to deftly scroll through menus whether they moved up and down or flicked across their arm.

The system could use wireless technology like Bluetooth to transmit commands to many types of device – including phones, iPods and even PCs. The researchers will present their work in April at the ACM Computer- Human Interaction meeting in Atlanta, Georgia.

Body control

Pranav Mistry of the Media Lab at the Massachusetts Institute of Technology warns that users will have to position the armband very precisely so the projection always appears in the right place.

Nevertheless, Skinput looks a promising idea, says Michael Liebschner, director of the Bio-Innovations Lab at Baylor College of Medicine in Houston, Texas, who has worked on bone acoustic conduction technology for gadget-to-gadget transmission.

“This sounds a very feasible approach to using the body itself as an input device," he says. "When you are immersed in a virtual game using a head-mounted 3D display, you cannot just take it off to fiddle around with control buttons. This will make things much easier.”

Fonte: http://www newscientist.com

No texto, a expressão “It” refere-se a

Para responder a questão, leia o texto a seguir.

Body acoustics can turn your arm into a touchscreen

By Paul Marks | March, 2010

Finding the keypad on your cellphone or music player a bit cramped? Maybe your forearm could be more accommodating. It could become part of a skin-based interface that effectively turns your body into a touchscreen.

Bodily interface (Image: ACM)

Called Skinput, the system is a marriage of two technologies: the ability to detect the ultralow-frequency sound produced by tapping the skin with a finger, and the microchip-sized "pico" projectors now found in some cellphones.

The system beams a keyboard or menu onto the user's forearm and hand from a projector housed in an armband. An acoustic detector, also in the armband, then calculates which part of the display you want to activate.

But how does the system know which icon, button or finger you tapped? Chris Harrison at Carnegie Mellon University in Pittsburgh, Pennsylvania, working with Dan Morris and Desney Tan at Microsoft's research lab in Redmond, Washington, exploit the way our skin, musculature and skeleton combine to make distinctive sounds when we tap on different parts of the arm, palm, fingers and thumb.

Bone machine

They have identified various locations on the forearm and hand that produce characteristic acoustic patterns when tapped. The acoustic detector in the armband contains five piezoelectric cantilevers, each weighted to respond to certain bands of sound frequencies. Different combinations of the sensors are activated to differing degrees depending on where the arm is tapped.

Twenty volunteers tested the system and most found it easy to navigate through icons on the forearm and tap fingers to actuate commands.

“Skinput works very well for a series of gestures, even when the body is in motion, “the researchers say, with subjects able to deftly scroll through menus whether they moved up and down or flicked across their arm.

The system could use wireless technology like Bluetooth to transmit commands to many types of device – including phones, iPods and even PCs. The researchers will present their work in April at the ACM Computer- Human Interaction meeting in Atlanta, Georgia.

Body control

Pranav Mistry of the Media Lab at the Massachusetts Institute of Technology warns that users will have to position the armband very precisely so the projection always appears in the right place.

Nevertheless, Skinput looks a promising idea, says Michael Liebschner, director of the Bio-Innovations Lab at Baylor College of Medicine in Houston, Texas, who has worked on bone acoustic conduction technology for gadget-to-gadget transmission.

“This sounds a very feasible approach to using the body itself as an input device," he says. "When you are immersed in a virtual game using a head-mounted 3D display, you cannot just take it off to fiddle around with control buttons. This will make things much easier.”

Fonte: http://www newscientist.com

Assinale a alternativa cujo segmento contém a resposta à pergunta “But how does the system know which icon, button or finger you tapped?”.

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