Wednesday, August 1, 2018

The Atlanta Algorithm

[Aug 1st] As with many other cities in the US, Atlanta has a public transportation network (known as MARTA), which is a joke. In fact, the metro is ok. But my issue is with the buses. Unfortunately, most of Atlanta is not also walkable. Lack of proper sidewalks in the residential neighborhoods. Life in Europe has taught us that it is not necessary to drive, and it is ok to use the public transport. :D Given this state, we choose to live close to my university. 20 minutes by walk.


There is also a bus stop close to both my apartment and my lab. A bus (#6) passes by every 30 minutes, connecting my home to my lab in the university. I usually walk to my lab, and return, by foot. But since I have a free monthly public transportation pass from the university, I decided to use it.


Before leaving home, I check the app to confirm the arrival time of the bus. However, the timing is not accurate. The bus usually comes with a time interval [-3:5], that means 3 minutes earlier to 5 minutes later. But now for the third time in a row, the bus came 10 minutes late. To ensure I do not miss the bus, I always arrive 3 - 4 minutes earlier. Therefore, I leave home 7 minutes earlier than the bus' arrival time at the bus stop (since I need to walk a bit to reach the bus stop).


Let's look at one specific example: Today, I left home at 7:43 to catch the bus that would arrive at 7:50. I reached the bus stop at 7:46. The bus eventually came at 8:10. Then, the bus reached the destination in a few minutes, and I entered the lab at 8:18. If I walked, I would have reached the lab at 8:03. The bus cost me 15 minutes extra.


In a regular/successful day, this would go like this. I leave home at 7:43. The bus comes at 7:54, and I arrive at the lab at 8:01. If the bus reaches my bus halt earlier than usual, the bus driver stops in the bus stop before the Emory village for a few minutes to make sure the bus does not proceed to the next stop too early?!?!?!. So it never happened that I arrived before 8:01 when I use the bus. So I can conclude that using the bus costs me 18 minutes in the best case and 35 minutes in the worst case. On the other hand, if I walk, I take 20 minutes, a constant time, regardless of rain or shine.



[Update: Aug 2nd]
So I found that "MARTA On the Go" application actually offers a real-time schedule of the bus, unlike Google maps which shows a static schedule. Today I checked the bus time just before leaving home. The bus was on its way. It said "6 minutes late" with the current location. MARTA On the Go does not show the estimated arrival time at each stop with this dynamic information. Rather, it shows the current location of the bus (that means, you should have an idea of the road map, or you need to use it in conjunction with another application such as Google maps) and the current delay. With the 6 minutes delay, the bus can reach my stop in 4 (if the driver manages to catch up) - 8 (if the bus further gets delayed) minutes late, I estimated. With this estimate, I left home at 7:48 and arrived at the stop at 7:50. The bus eventually arrived at 8:02. So it actually got delayed 12 minutes (apparently it got delayed 6 more minutes since I checked). I reached the destination bus stop at 8:12 (13 minutes later than the original time). I arrived at the lab at 8:13. 25 minutes (i.e., 5 minutes later than my walking time). I noticed from the app that the next bus got delayed 8 minutes to reach my starting bus stop. While this app does not solve the inefficiency of the public transport, it certainly mitigates the uncertainty and help plan the timing better.

Every city's public transportation system teaches me some new life lesson. I learned something in Jeju. Now in Atlanta. I like these life lessons - I do not underestimate them. Trust yourself, instead of trusting an external element!


Monday, June 18, 2018

My "CAT"/ Ph.D. Proposal

Today I presented my CAT, " Software-Defined Systems for Network-Aware Service Composition and Workflow Placement". I should have presented the CAT much earlier. However, it was delayed, and now I have presented it just a few months before my final defense. I received a grade of 18/20 for the CAT. The presentation slides are attached below.



Tuesday, May 15, 2018

Moving Bits with a Fleet of Shared Virtual Routers

Today I presented my paper titled "Moving Bits with a Fleet of Shared Virtual Routers" at IFIP Networking 2018 in Zurich. The presentation was very interactive. This was my work from KAUST. It is nice to be back in Zurich.


Abstract: The steady decline of IP transit prices in the past two decades has helped fuel the growth of traffic demands in the Internet ecosystem. Despite the declining unit pricing, bandwidth costs remain significant due to ever-increasing scale and reach of the Internet, combined with the price disparity between the Internet's core hubs versus remote regions. In the meantime, cloud providers have been auctioning underutilized computing resources in their marketplace as spot instances for a much lower price, compared to their on-demand instances. This state of affairs has led the networking community to devote extensive efforts to cloud-assisted networks --- the idea of offloading network functionality to cloud platforms, ultimately leading to more flexible and highly composable network service chains.

We initiate a critical discussion on the economic and technological aspects of leveraging cloud-assisted networks for Internet-scale interconnections and data transfers. Namely, we investigate the prospect of constructing a large-scale virtualized network provider that does not own any fixed or dedicated resources and runs atop several spot instances. We construct a cloud-assisted overlay as a virtual network provider, by leveraging third-party cloud spot instances. We identify three use case scenarios where such approach will not only be economically and technologically viable but also provide performance benefits compared to current commercial offerings of connectivity and transit providers.

Tuesday, May 1, 2018

The Conference Survival Guide

SoCPar 2010, Paris
I enjoy attending conferences. I never attended a conference when I did not have something to present. This is usually because of the funding, as it is unlikely for me to get funded to a conference when I am not presenting my work. So far, WWW2011 is the only conference that I attended without having a paper to present. Conferences help me fine tune my research, make new friends and build a network. I still vividly recall my first conference, SoCPaR 2010. I was presenting our paper, and luckily for me, I had 3 of my best friends with me. I was not alone. We all were co-authors of the paper, a team effort during our BSc times. I recall presenting the paper confidently and discussing with other researchers. Prof. Ajith Abraham of MIRLABS, who was organizing the conference remarked that he remembered us, a 4-member team arriving in Paris all the way from Sri Lanka to present our paper. It was a nice experience to travel to Paris, my first overseas trip. It was a cold winter, full of snow. The conference was held in Université de Cergy-Pontoise. I met two researchers from the same university in latter conferences, bringing back memories from 2010. 

Be prepared for the delayed luggage
Interestingly, the second conference I presented my paper was again in Paris in 2014. This time, it was MASCOTS, and this was the first paper of my MSc, and also the first paper as the first author. The other conference as part of my MSc research was UCC'14 in London. I met my friend there after a long time, and we had some good chat!

I love visiting different countries and various cities. Attending conferences also offers this opportunity. Moreover, the conferences immediately give you some partners to travel with. You meet some random researchers and make friends with them - because of the shared research interest (or purely because you are from the same university, country, or have something in common other than the research interest). For the rest of the conference, you can explore the city with them.

I try my best to attend all the sessions at the conferences. However, sometimes it is inevitable that I miss one session. Especially the earliest one on the day following my presentation. This is because sometimes I feel tired after the long presentation and its preparations and oversleep the following day. I also enjoy the coffee breaks, lunch times, and the gala dinner. The ideal time to make friends. You are lucky if your presentation comes on the first day. You can relax and enjoy the remaining talks/sessions without having to check your presentation once in a while.

I have attended several conferences during my Ph.D. As a result, I have traveled to several cities: Tempe, AZ, USA (IC2E'15); Berlin, Germany (IC2E'16); San Francisco, CA, USA (AMIA'16 and ICWS'16); Rhodes, Greece (CoopIS'16); Valencia, Spain (SDS'17); Munich, Germany (VLDB'17); Barcelona, Spain (SDS'18); and Zurich, Switzerland (Networking'18). Sometimes, I have one or two additional days following a conference. I use these days to travel to a near-by country or a city. Conferences always leave me with good memories - no exceptions so far. They give me more knowledge, and also other experiences with travels. I thank all the conference organizers and volunteers who make sure that we all have good experience attending the conference.

Saturday, April 28, 2018

The Road to Monaco

The Monte Carlo Casino
Finally, I visited Monaco! It was very similar to my trip to Andorra in 2015. When I visited Barcelona for an EMJD-DC Spring Event, I had an extra day. So I took a bus to Andorra and spent a whole day there before returning to Andorra. This time I had a free day after the conference. I also found a cheap return flight ticket (50 Euro Vueling) to Nice from Barcelona. From the Nice airport, you can get a bus (no 110) to Monaco. Purchase the tickets at the ticket office as the bus driver does not sell the tickets.  A return trip to Monaco costs 33 Euro. One way costs 22 Euro. So I purchased a return ticket.


Once you have your bus ticket, proceed to catch the bus at the bus terminal #3 right outside the airport. The bus is hourly. There is also a bus that goes to Menton with the same number (no 110). At least during our trip, two buses left at the same time, ours with the destination to Monaco, and the other to Menton (a city in French Riviera that comes right after Monaco). Make sure to get on the right bus. The bus drivers speak good English, and you will be fine.

Monaco is the smallest UN member nation since Vatican is not a UN member state. Before the journey started, the bus driver proceeded to ask from each of us where are we going. By doing so, he made sure that no one missed their bus stop. That is a pretty smart thing to do. I got down at the Monte Carlo casino with many others. The bus goes until the Monte Carlo beach. There was a tourist information desk in a short walking distance from the bus stop. There was a hop-on-hop-off bus. However, I did not take that and proceeded to walk across the entire country. Thanks to its small size, I managed to create a record of my own to have walked across a country for the first time! :D I discourage anyone from taking the hop-on-hop-off bus. It goes in parallel with the coastal line and does not even go to the Jardim Exotica (7 Euro entry fee). I easily walked to more places than what the bus covers. Also, why waste money on something useless? Monaco (combined with its towns such as Monte Carlo and Monaco Ville is entirely walkable). It also has a complete transport network of buses consisting of public buses.
Monaco is a rich country. A small 19 sq meter studio apartment costs 2,500 Euro per month as rent, excluding the utilities, as I found from an apartment agent advertisement in Monte Carlo. I paid 500 Euro for a studio of the same size inclusive of all the costs in Lisboa. I know people earn in Monaco much more than in Portugal, while not having to pay taxes. I had a good meal (bread, starters, entry, main dish, and dish), a menu option for 29 Euro (34 Euro including the glass of wine). It was a very crowded simple restaurant. Must be one of those on the cheaper side of the price spectrum as far as Monaco is concerned, I guess. I also found other restaurants that are more expensive.

There were several casinos including the Monte Carlo Casino and Cafe Paris Casino near the bus stop. Several shops selling luxury brands, and there was also a very nicely illuminated shopping mall with many such stores, giving it a golden feeling. As far as I noticed they did not have our cheap shops such as Zara and H&M. There was also a nice park with walking trails and a Japanese garden. I paid a visit to both. I avoided the Jardim Exotica as its entrance is not free. I visited the cathedral. Ok, if you are still reading the blog post, by now you would have identified that Monaco is not just casinos and shopping malls.

I walked across the beach until the end. I was thinking - where to get the bus now?! Luckily I found the bus stop of Monte Carlo Beach easily as I step out of the beach, completing my long walk. So did not have to spend time trying to locate it, or returning to the stop I arrived at. While waiting for the bus, a very old lady (in her 80s) came to me and asked me something in French. I told her that I did not understand. She immediately switched to English and asked me to tell her when the bus number 6 arrives. We immediately proceeded into a long conversation. When I asked her how many languages she can speak, she proudly answered: "oh, many." She happily recalled her life with three passports (born in France, 1 km from the bus stop, and having a husband with a Switzerland mother and a Switzerland passport - and thus having passports from Monaco, France, and Switzerland). Since she lives in Monaco, she has a Monaco passport and does not need to pay taxes. "That's the good thing about this," she claimed.

She also asked about what I am doing in Portugal. When I said I am studying, she proceeded to ask my age, and gave a look with a face, "Dude, that is too old of age to study. Did you fail your school or something?" lol. I tried to explain to her what is a Ph.D. I am pretty confident she knows what that is, given her exposure to the world (She has traveled as far as Hong Kong and her husband worked as a hotelier). But probably due to her difficulties in hearing, she did not quite catch what I said. Before I tried to explain her, the bus number 6 arrived. I stopped the bus for her and told her her bus is here. She thanked and greeted me good luck and proceeded to board the bus. I like nice people. They give you good memories that are hard to forget.

I returned to Nice to catch the last flight to return to Barcelona. I also saw the same two couple (looked like a young couple with the lady's parents) that came with me on the bus from Nice to Monaco. Previously on the bus, we shared a brief smile. The young lady came to me and asked something in Spanish, "blablabla, Moh-nuh-koh?" I understood she was asking something about Monaco. But not sure what is that she is asking about. I smiled and replied, "Sorry, I do not understand." I hate to say that. But unfortunately, I am not great at picking up with natural languages. :( She replied, "Monaco - good?" while giving a thumbs-up gesture. I said, "ah, yes, yes, good." giving back a thumbs-up, and asked her back, "And you? How was it?" She replied, "Yes, good! good!!" with a big smile. We all boarded the flight. I am happy to know that it is not just me doing this crazy travel of a same day return flight to Nice from Barcelona just to go to Monaco and return on the same day. There were 5 of us, including the young and old couple. I am not alone in this world. We are all similar in our uniqueness.