Bagalamukhi Paintings

It's an Indian paintings.

Lab MT - Falling down more than 20 times while learning ski

Day before yesterday I went to ski with entire members of our lab to a ski resort called Oak Valley. We skied for 8 hours including night skiing. Now I am feeling pain all over my body. I fall down more than 20 times. By mistake, I didn’t lock my shoes, so it’s slightly loose that is the reason why I fall down several times. However, it’s a nice experience. I enjoyed a lot. I am worried now not because I have pain in my body but I have to go to Australia for presentation, I didn't prepare for my presentation.

Kazi, Jonayed (Bangaladesh), me, Prof. and doughter, Dawun (Korea), Farruh (Uzbekisthan) and Deoksu (Korea) from left to right

Deoksu, Kazi, me, Key young, Farruh and Jonayed


Deoksu, me and Farruh

Expensive NEPAL

Today, I found a product named Nepal EVO GTX in Korean ebusiness site. I surprised with the price 785,000, even a discount price is 700,000 Korean won (around 500 USD or NRs 40,000). According to the manufacturer LA Sportiva, it’s the best leather mountaineering boot on the market. The Nepal last offers an excellent fit for any foot and is easily adjustable with the removable/adjustable tongue. It’s around 1 KG.

Because of few reasons I am particularly interested in it. One is I like adventure and recently I am going to skiing. Another is, the name of the shoes is Nepal, the name of my country.Finally, the shoes is looks like very durable and comfortable.

New Google

Thesedays, Google is a synonyms for search engine. People say googling for search in the internet. Many new innovative (not sure how innovative they are though) search engines are showing their existence in the market. 

Today, I received an email from SONSIK yahoo group member mentioning that the search engines that we are mostly using Google and Yahoo, there is a new searching engine promoting by Nepalese. The mail requested to try the search engine. I tried it and searched some stuffs too. I read the About Us column. It seems that basically the search engine is operating from US. It has offices in both country US and India. The promoters are seems to be Nepalese and Indian origin. The official blog is written in January 28, 2009, looks pretty new. 

The name of the search engine is given Sagoon. Although the GOO of Sagoon looks like taken from Google, it’s not true. It’s derived from Sanskrit which means Auspicious or ushering good results. In News section there are two language changing options – Nepali and Hindi. It can be assumed that this search engine is targeted to the Nepali and Indian users. History shows that Google and Yahoo are not big success in non-english speaking countries like China and Korea. So this search engine can be very popular as a regional search engine. 

The founder of the company Sagoon Inc. Govinda mentions in the blog that it’s the beginning of their journey, a journey with bigger challenge. Of course, as there are many Big Bosses in search engine industries occupying large market shares already, it might be challenging for Sagoon. 

Anyway, finger crossed to Sagoon team for their success. 

www.sagoon.com

Mata Saileshwori, Silgadhi, Doti

Photo taken by two different nonprofessional cameras. 

Why TCP modeling?

There are certain things we can achieve with TCP modeling that cannot be achieved with simulation. Some of them are as follows. 

• We can model some uncertainties using stochastic process that cannot be determined by simply simulation. For example, number of current TCP connections, how much bandwidth is occupied by the non TCP transport protocols and what is the effect of those in TCP etc. 
  
• TCP operating scale is very large in terms of geographical scale and the number of inputs/outputs. To simulate the large number of inputs/outputs and geographical scale is not easy due to hardware constraints (some times budget constraints as well).
  
• Mathematical models are required to quantify metrics that define system performance and develop control strategies that result in the optimum being achieved.
• It also helps to determine how close it is to achieving a system optimum, as defined by a specific cost function, and subsequently identify issues that need to be addressed in future control protocol. 
  
• TCP is already mostly used transport layer protocol in the world. To test some optimization in it is not easy to implement in real world scenario and observe its performances. So, before implementation any optimization patches it is very much necessary to model it. Some examples of those patches are Fast Retransmission and Fast Recovery. These were not in the very first version of TCP.
  

The role of the "gateway" option of tcpdump

‘Gateway’ in tcpdump specifies a name of gate that transfers the packet. We can use gateway to monitor traffic from specific TCP/IP applications at strategic locations of a given TCP/IP network. For example to print all ftp traffic through snup gateway the command is as follows:
#tcpdump 'gateway snup and (port ftp or ftp-data)'

To print IP packets longer than 576 bytes sent through gateway snup the command is:
#tcpdump 'gateway snup and ip[2:2] > 576'