Sunday, June 27, 2010

More on the Evo

I decided to keep my Evo and switch to Sprint. The switch from the G1 to the Evo was a no-brainer. The Evo is far far superior, as it should be since it's a later generation of an android-based device.

I did get a chance to play with the iPhone4 the other day and I was quite impressed with the UI and general feel of the phone. Functionality-wise, I think the Evo is better (Evo versus iPhone4), especially if you're a power user and use the internet a lot. I've found that the 3G AP feature is not only extremely useful for me, but it is far more stable than the access point connection I have at the CS lab at school. The bandwidth is great for productivity. I've evened streamed tv using the slingbox client, for hours on end without any hitches. It's really fantastic!

However, that said, the iPhone's UI is FAR superior. I very much hate to admit that but it's true. Their engineers and artists have clearly spent an inordinate amount of time making the feel of the phone just right. They really nailed it. It's sensitive to the user's touch, but not too sensitive. It's very responsive and is able to decipher user gestures with high accuracy and it just looks so pretty. I understand why it is that people love the phone so much.

From a functionality perspective, I think the Evo is a better phone. Once 4G is ubiquitous it will make the phone much more valuable. But it's going to be difficult to get the lay-person user to see that those differences matter since the lay-person surely doesn't use the sophisticated features. Apple has focused it's attention on the lay user while not compromising too much on the technical end of things. It's certainly a nice tradeoff. Secondly, most people could care less about Apple's practices because it really does not affect them. I am against apple in principal, since they have a closed platform -- a walled garden usage model. Andriod is quite the opposite, and there are certainly tradeoffs to consider there as well, but all things being equal, i'd rather have choices.

My neighborhood -- Woodside

Just a couple of pictures of where I grew up. My family still live there and it's where I call home when I visit NYC. Woodside, Queens: Always reppin'










Thursday, May 20, 2010

Sprint Evo Review

There was no 4G coverage here in Berkeley so, for now, all the tests were run on the 3G network.

===============================
Download speed: ~500 Kbps
Upload speed: ~120Kbps
===============================

Supposedly the 4G network is 10x faster. That would make the connection speed similar to the one I have at home. That would be 5Mbps down and 1.2 Mbps up. That's pretty amazing.

The live the tv feature is pretty incredible. And the fast that the data is being carried over the 3G network is actually quite impressive.

The keyboard facility is not as bad as I expected it to be. Although it's seriously lacking in comparison to the keyboard on the droid or the G1.

Battery life. It might be a good idea to really run some battery tests on this thing. Live TV, Access Point feature, etc. Those things have really got to drain the battery. It's likely a function of the cellular radio's duty cycle. Probably easy to do the 'back-of-the-envelope' calculation to figure out how long the battery is expected to last.

The screen is huge, and clearly this also drain the battery.

Not all 3G networks are create equal. It comparison to T-mobile's 3G network in this area, there really is no comparison. The Sprint 3G network is significantly better than the t-mobile network. I can barely hold a voice call for my drive from school which is only 3 miles/10 minutes aways by car.

Radio -- it has one and it's awesome. I put on some headphone and was able to get local radio stations. Radio hasn't been integrated into any of my devices and that has made it very difficult to keep up with radio shows I hear in the morning on my way to school. Not all the stations I listen to have online/streaming audio stations, so when i turn the car off upon arrival, no more radio show.


More to come....

Monday, January 4, 2010

Open research questions in IS4

I'm working on building a sensor storage system with features that will make it easy to integrate multiple stream of data into a database for long-term storage, real-time streaming, and perhaps real-time trending/search. The name of the system is the Integrated Sensor-stream Storage System or IS4 and there is more information here.

Long-term storage is trivial. The challenge or contribution in this area is really the protocols and associated schemas for integrating data stream from a heterogenous set of sensors. There are also challenges that have been directly addressed in the literature with respect to the integration of data that does not have a unifying condition. In other words, there's no column whose values match in order to run a join across columns. It's important to note that in this work, we assume that the data is all timeseries data. Furthermore, the associated metadata is also timeseries data. Therefore we can use aggregation, windowing, extrapolation, and interpolation techniques to create views (temporary and materialized).

From the ActionWebs meeting, the main take-away related to my work is the idea of the relationship between models and data. Up to this point our mindset has been on applying a model to the data, for example, running linear interpolation in time and surface-fitting in space to generate a 2D temperature-distribution map overlayed on a map of a space. But this kind of interpolation has major flaws. Especially when dealing with temperature data, linear interpolation has no bounded contraints. There is no notion of heat transfer, no notion of space separation, no physical model that can be fed the collected data so that observations are based more on physical reality rather than pure mathematical modeling. Really, the model should set the context for the data and the data should then inform the model. Adjustments to the model should made according to the data.

On the data model...

I am reluctant to use the word column or view since it implies a relational data model. The data model is object-oriented. We can, however, map data objects to tables. The concept of a column is an ordered vector of object attribute values for the same attribute label. The row corresponds to an object of attribute-value pairs. Views are comprised of a mapping of attributes in column form. Since all objects are timestamped, we can use a model (physical, mathematical, or otherwise) to fill in any missing values so that a merge/join can be performed.

Open challenges:

1. Real-time streaming queries
2. Actuation
3. Staged pub/sub system
4. Alerts and modeling
5. Query language

Real-time streaming queries
This problem has been addressed in the literature. Windowing is one of the most common techniques.

Actuation
This is a problem in sensor networks that has not been addressed. Most papers mention the need for actuation, very few actually do it.

Staged pub/sub system
Client systems to IS4 will have the ability to subscribe to various stages of incoming data and processing stream. This implies the need to paint stream flows and forwarding those flows to all subscribers.

Alerts and modeling
Models used to apply to incoming data; data informing the model for adjustments. Deviations of data from model beyond pre-defined thresholds should trigger either alerts to client processes or online model adjustment.

Query language
How do we query the data? If end-clients are not processes by a human user, should we provide a SQL-like to allow users to express what they would like from the data without having to express how to get it.

[more later]