2008年1月4日金曜日
2008年1月2日水曜日
Meeting memo-30/12/07
1. Issue of scenario
+Global map
-hight-popularity/frequency
-colour - types of music
-colour-freshness of the information
-2D map(colour-density)
-Size of the Map
-I like it -privacy(ad) Should we really need personal information?
+Function I like it
-to tell specific personal information is bit dangerous.
it might cause the issue of AD. some company use this info.
So think about the amount of information we give.
2.Technical issue
+pocket issue ( How GPS can work when the object is in the pocket)
+size of the bubble-10m
if the users works 4m/sec, it takes 4-5sec these users cross by each other.
But, usually to listen to sample music file, each company provide 15-sec.
Maybe, it should be better if each of them can hear at least 7-8sec.
In this case, there is two way to achieve this condition.
1. change the size of the bubble ex) n=>15m
2. when people are crossing, they can exchange 10sec of music file.
so, still people can hear 10sec.
(And then, the volume does fade in and fade out)
-how much data we can send
with Wi-Fi : Each 1sec-20sec of music files
+Accuracy of GPS is 10-15m. so only with GPS we can not show our position on the screen as we want. So the possibility is here.
1. put additional emitter and receiver for each devise.
-put the some sensor and signal
tech how it works) each 0.5 sec culiculate the speed of the signal from other side
But in this case, we can know the distance but not orientation(position of the other user)
2.celle phone-antena- but still its accuracy is wider than GPS
+rather than Wi-FI , bluetooth must be better(can be 10m)
-Wi-Fi takes lots of power
2007年12月31日月曜日
Ultra wideband
[Difinision]
Ultra-wideband (UWB, ultra-wide band, ultraband, etc.) is
a radio technology. It can be used at very low energy levels for
short-range high-bandwidth communications by using a larger
portion of the radio spectrum. This method is using pulse coded
information with sharp carrier pulses at a bunch of center frequencies
in logical connex. UWB has traditional applications in non cooperative
radar imaging. Most recent applications target sensor data collection,
precision locating and tracking applications.
[Applications]
Due to the extremely low emission levels currently allowed by
regulatory agencies, UWB systems tend to be short-range and indoors
applications. However, due to the short duration of the UWB pulses, it
is easier to engineer extremely high data rates, and data rate can be
readily traded for range by simply aggregating pulse energy per data bit
using either simple integration or by coding techniques. Conventional
OFDM technology can also be used subject to the minimum bandwidth
requirement of the regulations. High data rate UWB can enable wireless
monitors, the efficient transfer of data from digital camcorders, wireless
printing of digital pictures from a camera without the need for an intervening
personal computer, and the transfer of files among cell phone handsets and
other handheld devices like personal digital audio and video players.
UWB is used as a part of location systems and real time location systems.
The precision capabilities combined with the very low power makes it ideal
for certain radio frequency sensitive environments such as hospitals and
healthcare. Another benefit of UWB is the short broadcast time which enables
implementers of the technology to install orders of magnitude more transmitter
tags in an environment relative to competitive technologies. USA based Parco
Merged Media Corporation was the first systems developer to deploy a
commercial version of this system in a Washington, DC hospital.
New UWB Products from HITACHI[link]
Accuracy- 30cm