Google Home and Project Soli = ?

Google Home is coming out today. It is getting super excited to see that Google is using its cutting-edge technology on smart home, just like Amazon Echo and Samsung Atrik. What is interesting about Google Home is that we see many other opportunities other than just voice commands.

While security is surely one thing (and one big thing of course) in these smart home devices (or precisely in the IoT development), I thought of one thing in particular: sensing. Although it is not limited to Google Home, here I use it as an example. Continue reading Google Home and Project Soli = ?

Turn Stale SmartPhone Into SecCamera?

I was having this idea for a long long time. Yesterday my friends and I were talking about it again. Well, apparently others have done so, if you Google it. Below is a very short list of things I found online (there are tons of apps and companies doing so).


But it occurs to me to understand why this method isn't so popular. Many companies are making expensive security cameras, and people still buy them. Maybe because we trust things that are dedicated to what they are made for? Then I see that Yi (belonged to XiaoMi) released low-cost security camera (around $30), and a lot of people like it, including me. I realized that it isn't we don't trust low-cost solutions to leverage old smartphones for surveillance. We like them and buy them because we simply don't care, because most of us simply like new stuff.

No matter how easy the setup is for the whole "using old smartphone as monitoring system," old stuff is old. We no longer want to touch the old phones. Maybe they are painfully slow. Maybe they have been sitting in the dust for so long. Maybe some functionality in the phone do not work any more. Maybe they carry so many memories and emotionally we do not want to revisit. And we move on, we get new phones, why do we turn back?

From "We Can" To "We Should"

Just finished my cruise trip to Mexico with my gf and it was a fantastic experience, though I had to read around 100 papers and organize them for finding my potential research directions and wrote the journal.. I managed to do so before the start of new year and enjoyed the trip at the same time.. phew..

Anyway. After reading the papers about sensing and wireless at MobiCom, MobiSys, SenSys, NSDI, HotMobile from 2012 to 2015, I find the interesting phenomenon. We always claim that we can do this by using that. Taking "localization" as an example, it's been studied for years and people use all kinds of technologies (e.g., FM, Wi-Fi, RFID, sound, geomagnetic, visible light, 60GHz, etc.) to accomplish meter-level or cm-level or even mm-level accuracy. Of course, they are done by assuming various kinds of scenarios. And we show that we can do it. Most introductions would look like:  Continue reading From "We Can" To "We Should"

Brief on Synthetic Aperture Radar Imaging Resolution

I assume readers already know the definitions of:

  • Frequency of a wave \(f\): number of periods per unit time
  • Wavelength \(\lambda\): distance between each period
  • Propagation velocity \(v=\frac{1}{\sqrt{\mu\epsilon}}\): wave traveling speed, here assuming the speed of light \(c=\lambda f\) in the air
  • Beam width \(\theta\): the angular spread of the radar beam, approximated by \(\theta=\frac{\lambda}{L}\) in radian, where \(L\) is the size of real aperture

Continue reading Brief on Synthetic Aperture Radar Imaging Resolution

UnwiredLab and The Fun

Never thought crawling data from a company will be found out so fast.


The thing is UnwiredLab has extensive dataset that allows them to derive the cell tower location. And they sell the number of queries for the service. Similar services include Google Map, OpencellID, Combain, CellIDFinder, etc. UnwiredLab provides a trial/free account that allows 50 queries per day, 1500 per month. Because of my research purpose, I need extensive number of queries. I wrote my crawler and wanted to test its robustness, but obviously 50 isn't enough for testing. So I created 6 accounts in a row, with Tor, trying to escape from their spam detection system.  Continue reading UnwiredLab and The Fun

The Uniform and Separation of Devices

Not so long ago (maybe just several years ago), people had succeeded to unify multiple devices into one. For example, cellphone is now multi-functional and has replaced many utilities we saw in the early years. People tended to squeeze everything into a small device, and that led to the what smartphone looks like today. We don't need map anymore since there's GPS and Google Maps. Post-it turns unpopular since there are multimedia notes taking apps. There are countless things that are replaced: cameras, music stations, radios, CDs, books, flashlights, compass, and so on so forth. People literally thought a smartphone could replace everything we have in life. One recent example is ASUS's Padfone. Continue reading The Uniform and Separation of Devices

Attending NSDI 15'

This has been my third conference event since I became a PhD student at SANDLab. NSDI 15' was between May 4 - 6, held in Oakland, CA. My friends were saying things like "do not go out at night" because of so many negative news about Oakland downtown. Well, I stuck to what they suggested and stayed in hotel at nights - not only because of the potential dangers but also due to homework due. Yep, skipping two classes and TA discussion is never fun and you have to do the work at night. 😛

NSDI is a conference that pays much attention in practical system designs. Most topics are in data centers, software-defined networks, and operational systems. Although there were wireless and physical layer sections, based on what I observed, most people were more interested in previous topics I mentioned. This year there are three best paper awards, which are by Matthew Grosvenor et al., Dan Ports et al., and Ben Pfaff et al. Here are some papers I think very interesting and I learn new things from. Continue reading Attending NSDI 15'