Saturday, July 31, 2010

DEMS: A Data Mining Based Technique to Handle Missing Data in Mobile Sensor Network Applications

In Mobile Sensor Network (MSN) applications, sensors move to increase the area of coverage and/or to compensate for the failure of other sensors. In such applications, loss or corruption of sensor data, known as the missing sensor data phenomenon, occurs due to various reasons, such as power outage, network interference, and sensor mobility. A desirable way to address this issue is to develop a technique that can effectively and efficiently estimate the values of the missing sensor data in order to provide timely response to queries that need to access the missing data. There exists work that aims at achieving such a goal for applications in static sensor networks (SSNs), but little research has been done for those in MSNs, which are more complex than SSNs due to the mobility of mobile sensors. In this paper, we propose a novel data mining based technique, called Data Estimation for Mobile Sensors (DEMS), to handle missing data in MSN applications. DEMS mines the spatial and temporal relationships among mobile sensors with the help of virtual static sensors. DEMS converts mobile sensor readings into virtual static sensor readings and applies the discovered relationships on virtual static sensor readings to estimate the values of the missing sensor data. We also present the experimental results using both real life and synthetic datasets to demonstrate the efficacy of DEMS in terms of data estimation accuracy.

In DMSN' 2010

Saturday, July 24, 2010

Grand canyon

It is hard to explain why Grand canyon is so amazing unless you be there. Mountain is something which amazes me all the time and Grand canyon with its color made me speech less. Here is something I need to share that I learned from my mistakes of Grand canyon trip.

1. Plan for at least seven days, this is so amazing place it is hard to see everything in short period of time. If you are planning for less than that all you can do is some photo session. If "be there, done that" is you intention then probably you can finish it up by few hours. But my recommendation is plan for at least seven days, find a quite place and try to feel the color and vastness of this awful mother nature's creation.

2. Don't make any arrangement to stay in a hotel. Staying at hotel is waste of money and time. You have to travel a lot back and forth. Make an arrangement for camping and that's the way you can enjoy the grand creation. And of course make some plan for hiking, Grand canyon trip without hiking is incomplete. Find a camping place near the Colorado river and spend some time. The quieter the place the better it would be. If you are in a group fix time to be alone.

3. Renting is a car is not a good option but I don't know about good public transportation. But surely if you rent a car left it somewhere before the camping. Grand canyon national park has some arrangements for parking and they are often very full. I recommend public transportation (if you have any).

4. Try to visit as many places as you can by walking (hiking). Do not drive, it is waste of your time. It is around 110F during summer with extremely low humid, so carry as much water as you can. Following the trails for hiking is a safe option but if you are little bit adventurous, you can do more than that.

5. It is really difficult to find food in Grand canyon area, so make some arrangement about the food beforehand. I would recommend light foods but you can carry some heavy meals and waste as less as possible time for food.

6. Skywalk is one of a kind engineering work, if you can appreciate its extreme engineering make a plan to visit there. If you have acrophobia then surely you would enjoy Skywalk. Either you have to have acrophobia or you have to have some knowledge about engineering to appreciate Skywalk otherwise it is a complete waste of money for you.

7. Finally try to avoid crowd. Scenic and crowd does not go together. I would recommend going to Grand canyon all alone and be there all alone is the best option.

I hope I covered all you need to know before you plan for Grand canyon. It's a one of a kind place and be there before your end. It is perfectly capable of changing your perspective.

Wednesday, July 14, 2010

Choices

I was walking alone thru a side show
With passion and pain on each side.
Something inside me was calling
For a chance to stay alive.

At the time I didn't know what was calling
As my head was buried in grief.
Today I heard what was crying.
My freedom calling me

And we all make our choices
Like a blind man feels his way,
And the choice I've made is simple;
Passion over pain.

When I got to the end of the side show
And looked back to where I had been,
My eyes filled with teardrops of loneliness
For the ones who will never be free

And we all make our choices
Like a blind man feels his way,
And the choice I've made is simple:
Passion over pain.

I thought of the children in the side show
As they wandered around so confused.
Some day they'll make their decision
But which one will they choose?

And we all make our choices
Like a blind man feels his way,
And the choice I've made is simple;
Passion over pain.

[Uriah Heep]

Thursday, July 8, 2010

Racism!

Once again racism. Racism is something I am encountering these days! It is not that other people are judging me, it is my friends(!) are judging other people. Very funny but true. Personally I hate racism, it hurts me when my friends say, stay away from race "X". A decent number of my friends are here in Norman now and unfortunately I have heard most racist comments from them. I don't know why but it hurts me. I hate racism. Segregating people is the last thing I would accept.

Racists are narcissists. Today they are segregating based on your color, tomorrow when everyone would have same color they will segregate based on something else, then something else, and so on. Human beings are social animal, and probably the worst byproduct of being a social being is racism. Its a shame for human civilization if we can't overcome such a small shortcoming. I have heard hundreds time that my friends are judged by their race; I know its true but to me that cannot be a justification of being racist. Racism is an ancient thing. It is taught in family and society, no one born with it.

Tuesday, July 6, 2010

OUTLIER DETECTION FOR DATA STREAMS

Outlier detection is a well established area of study for statistical data. However, most of the existing outlier detection techniques are designed targeting the regular data model, where the entire dataset is available for random access. Typical outlier detection techniques construct a standard data distribution or model from the entire dataset and execute their detection algorithms over each data point. Evidently these techniques are not suitable for online data streams where the entire dataset, due to its unbounded volume, is not available for random access. Moreover, the data distribution in data streams change over time which challenges the existing outlier detection techniques that assume a constant standard data distribution for the entire dataset. In addition, data streams are characterized by uncertainty which imposes further complexity. In this work we propose two outlier detection techniques, called Distance Based Outline Detection for Data Streams (DB-ODDS) and Automatic Outlier Detection for Data Streams (A-ODDS). Both techniques are based on a novel continuously adaptive data distribution function that addresses all the issues of data streams; but DB-ODDS identifies outliers depending upon a user-defined minimum neighbor density, whereas A-ODDS identifies the most deviated data points as outliers. We also present efficient and online implementations of the two techniques and experiments evaluating their accuracy and execution time using three real-life datasets from meteorological and energy consumption monitoring applications. The performance results show that DB-ODDS and A-ODDS are superior compared with existing techniques, and while DB-ODDS requires domain knowledge to function, it offers better accuracy and execution time than A-ODDS.

In case if you are interested what have I done for last six months. This is what have I done for last six months. I am tired of it.

Downtown train

Outside another yellow moon
has punched a hole in the night time mist
I climb through the window and down to the street
I'm shining like a new dime
The downtown trains are full
full of all them Brooklyn girls
They try so hard to break out of their little worlds

You wave your hand and they scatter like crows
They have nothing that'll ever capture your heart
They're just thorns without the rose
Be careful of them in the dark
Oh if I was the one you chose to be your only one
Oh baby can't you hear me now, can't you hear me now

Will I see you tonight on a downtown train
Every night, every night its just the same
On a downtown train

I know your window and I know its late
I know your stairs and your doorway
I walk down your street and past your gate

I stand by the light of the four way
and watch them as they fall, oh baby
They all having their heart attacks
They stay at the carnival
But they'll never win you back

Will I see you tonight on a downtown train
Every night, every night its just the same
You leave me lonely
Will I see you tonight on a downtown train
All my dreams, all my dreams fall like rain
On a downtown train

Will I see you tonight on a downtown train
Every night, every night its just the same

Will I see you tonight on a downtown train
All my dreams, all my dreams fall like rain
On a downtown train
On a downtown train
All my dreams fall like rain
On a downtown train

[Tom Waits; 1985] [Rod Stewart' 1989] [Youtube] [wiki]

I am suffocating, ..., suffocating, ..., suffocating...