FRENCH: Je suis en la vraie France

C'est ma premire article en français. Je sais il a beaucoup de erreurs mais pas de problem, je essayer pour ecrire en français de toute façon :). Après quelques articles je peux réduire les erreurs.

La semaine dernier j'ai changé ma appartment. Avant, mon appartment était plus loin de mon bureau. La nouvelle apartment est pas loin. Je peux a piéd meme si il ya une grave, manifastation etc. en train ou bus. La autre difference: j'ai habité en mémé batiment avec mon ami l'étranger. Cependant, maintenant je connaise moin personne que habite a coté de mon appartment. La troisième difference : je dois parler française parce que peuple ne parler pas l'anglais ici.

Donc, Je sens que je suis en la vraie France maintenant. Aussi, je connaître pourquoi je ne parler pas bien français. La réponse est simple, avant je n'ai pas habité en vraie france :).

Merci beaucoup pour lire ma premire article en francaise. à bientôt!

When will this recession ends?

Everybody in the world is affected by recession. All of them are eagerly waiting for its end date. Although it is hard to say when it is going to be end, history can assist to think about it. In this article, I will paraphrase the major recessions and their life period.

According to the Bishambher Pyakurel, there are many recessions since last 70 years [1]. The major recessions and corresponding durations are listed here:

  1. Recession during 1930 - 1932 : Duration= 43 months
  2. Recession during 1980-1981 : Duration= 16 months
  3. Recession during 1990-1991: Duration = mild
  4. Recession during 2001 : Duration = mild
  5. Recession during 2007: Started in December , End = Unknown

Furthermore, [1] states that there are 10 recessions since World War II and the average duration is 10.4 months. The current recession is already 17 months old, greater than the average duration, but the end date is not certain yet. It is predicted that the recession will end by the end of 2010. Lets hope it will end very soon.

References:

[1] My Republica

OPINION: "Life is a computer Program"

Despite some differences, a Life and a Computer Program have many similarities. In this article, I will analyze the similarities between them. First I define some of the terms as:

Computer Program: "A computer program is a collection of instructions"

Life :"A human life is a collection of instructions"

Programmer: One who writes programs

Environment: The way a program is written . A computer program is written in another computer program such as IDE.

States: A possible situation of a program such as on lab, running, paused, killed, died etc.



Terms
Computer Program
Human Life
Programmer
Computer Programmer(s)
The God (s)
Environment
Programming languages. Computer Program is written in editors, the computer programs. Not all editors can be used to write programs.
Human life is written using parents, the human lives . Not all parents are used to write human lives.



Execution
executes inside computers
executes in planets



Communication
communicate each other using protocols. Mismatch in protocols means no communication.
communicate each others using languages. Mismatch in languages means no communication.



Dimension
the dimension (height, width etc) depends on the the purpose and devices (computer, mobile phones, pda etc)
depends on the state to states.



States
in lab, written, running, killed, stopped
in belly, born, running, killed (by accidents, wars etc), died



Repairing
debugmedicate



Exception
handled by Exception handlers. Not all programs have such facilities like programs in C vs programs Java.
handled by Insurances. Not all people have such facilities.



War
A program can kill other programs with or without any reasons.
A human can kill other humans with or without any reasons.



Dependent
A program may depend on other programs like packages, APIs
A human may depends on other humans e.g. espouse, parents etc



Hierarchy
have hierarchies. Operating Systems are the big bosses.
have hierarchies. State heads, company executives are the big bosses..



Migration
Can be written in a lab and be sent to other places for execution.
May born in a place and live in another place


NOTE: If you have other similarities in your mind, let us share...

Can problems be solved by laws and legal systems ?

Many people think that laws and legal systems are the only thing that a nation should have in order to keep things in control. In South Asia, we frequently talk about laws. For example, we talk about the laws for women empowerment, child labor, terrorism, dowry etc. However, I personally don't believe only on the legal systems. What I think is that the laws and orders make sense when it applies to the region where basic needs are already fulfilled.

There is a saying - 'Hungry man is the angry man'. I absolutely agree with this statement. How can a law work if people are not certain for their daily foods, sufficient clean drinking water and shelters? We have made laws to prevent selling women for money. Is that working? Of course not! Hundreds of Nepalese ladies are being sold today to Bombay.

Moreover, we have made laws to prevent child labor. All we know that it is illegal to keep a child as a labor. But we forget when we return to our home. We are using them to clean dishes, wash clothes etc. No matter how educated the person we are, we usually forget such rules rules in our daily life.

The same pattern applies in case of terrorism. If a person is not getting items to eat, he could be easily influenced by terrorist groups as they offer a handsome amount of money to him or his family. As a result, he is motivated to carry out dangerous attacks. This is a ground reality we are seeing each day in our region, South Asia.

I believe no counties support dowry and all of them have made some forms of laws to prevent it. But we have witnessed its effect very frequently. In other words, people are not able to get married just because they haven't sufficient money to pay for the boy. After marriage also, many women are forced to do suicide just because their parents can't pay the money committed before their marriage.

These are just few examples. We have a bundle of such laws we are not working at all. The main reason is the lack of basic needs. If a person is not hungry, then only he/she starts thinking what a law is. The important question is not about whether laws are needed or not. The question is - How can we fulfill the basic needs of people so that the laws could be enforced ? People will be educated only when their basic needs are fulfilled and then think about their rights, the laws and legislative systems.

Definitions of few words in linguistics

Today I am presenting the definitions for few words which are commonly used in linguistic. They are Synonymy, Antonymy, Hypernymy, Hyponymy & Meronymy, and Corpus. Note that I have used Wikipedia for the definitions.
  1. Synonymy: Synonyms are the different words but refers to the same or similar meaning. State of being synonyms is called Synonymy and words which are synonyms are called synonymous. Example: Buy and Purchage (verbs), pretty and attractive (adjectives) etc.
  2. Antonymy: Antonyms are the words which have opposite meanings or refers to the opposite pair. e.g. Male and Female, Long and Short.
  3. Hyponymy & Hypernymy : According to the wikipedia [1], hyponym is a word or a phrase whose semantic range is included within that of another word. In other words, hyponyms are a set of related words whose meaning are specific instances of a more general word. Hyponym is also known as IS-A relations between concepts. On the other hand, hypernyms are the words which represents a broad meaning. To make the definitions clear, consider words car, automobiles, bus, plane and vehicle. Here vehicle refers all forms of transportation i.e. car, automobile, bus and plane. Thus, vehicle is hypernym of each of these words. Conversely each of those words are the hyponyms of the word vehicle.
  4. Meronymy and Holonomy: Meronymy (Part-Of relationship between concepts ) is opposite of Holonomy. Holonomy defines the relationship between a term denoting the whole and a term denoting a part of , or a member of, the whole. Putting differently, X' is a holonym of 'Y' if Ys are parts of Xs, or
    'X' is a holonym of 'Y' if Ys are members of Xs. Examples: 'tree' is a holonym of 'bark', of 'trunk' and of 'limb' | 'finger' is a meronym of 'hand' because a finger is part of a hand | 'wheel' is a meronym of 'automobile'.
  5. Corpus: A corpus is a large and structured set of texts which are used to do statistical analysis, hypothesis testing etc.
  6. Polysemy: A polyseme is a word or phrase with multiple, related meanings. For instance, the word wood can refer either 1. a piece of a tree or 2. a geographical area with many trees.
References:
[1] Wikipedia

Amsterday - 5th Busiest tourist destination in Europe

Source: http://oainfo.olympicairlines.com/destinations_ams_en.html

As I recently visited Amsterdam, I wanted to post an article about it (source mentioned above) so that I can quickly review the history of Amsterdam in future.

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History

The first known record of Amsterdam is 27 October 1275, when the inhabitants of a late 12th century fishing village who had built a bridge with a dam across the Amstel were granted freedom by count Floris V from paying a bridge toll . The certificate's wording (homines manentes apud Amestelledamme - people living near Amestelledamme) gives the first known use of the name Amsterdam, which by 1327 had developed into Aemsterdam. A local tradition has the city being founded by two Frisian fishermen, who landed on the shores of the Amstel in a small boat with their dog. In any case, Amsterdam's origin is relatively recent in comparison with other Dutch cities such as Nijmegen, Rotterdam and Utrecht.

In 1538 Amsterdam was given city rights in 1300 or 1301. From the 14th century on, Amsterdam flourished, largely on the basis of trade with the cities of the Hanseatic League. In 1345 a Eucharistic miracle occurred near the Kalverstraat and Amsterdam would remain an important pilgrimage city until the Alteration to the protestant faith; today the Stille Omgang - a silent procession in civil dress - remains of the rich pilgrimage history.

In the 16th century, the Dutch rebelled against Philip II of Spain and his successors. Both for his imposition of new taxes, the tenth penny, and his religious persecution of Protestantism with the Spanish Inquisition. The revolt escalated into the Eighty Years' War which ultimately led to Dutch independence. Strongly pushed by Dutch Revolt leader William the Silent, the Dutch Republic became known for its relative religious tolerance. Jews from Spain and Portugal, prosperous merchants and printers from Antwerp, Ghent and Bruges (economic and religious refugees from the part of the Low Countries still controlled by Spain), and Huguenots from France (persecuted for their religion) sought safety in Amsterdam. The influx of Flemish printers and the city's intellectual tolerance made Amsterdam a hotbed of the European free press.

The 17th century is considered Amsterdam's "Golden Age". In the early 17th century, Amsterdam became one of the wealthiest cities in the world. Ships sailed from Amsterdam to the Baltic Sea, North America, Africa and present-day Indonesia, India, Sri Lanka and Brazil, and formed the basis of a worldwide trading network. Amsterdam's merchants had the biggest share in the VOC and WIC. These companies acquired the overseas possessions which formed the seeds of the later Dutch colonies. Amsterdam was the most important point for the trans-shipment of goods in Europe, and it was the leading financial centre of the world. Amsterdam's stock exchange was the first to trade continuously.

The 18th and early 19th centuries saw a decline in Amsterdam's prosperity. The wars of the Dutch Republic with England and France took their toll on Amsterdam. During the Napoleonic Wars, Amsterdam's fortunes reached their lowest point. However, with the establishment of the Kingdom of the Netherlands in 1815, things slowly began to improve. In Amsterdam new developments were started by people like city planner Samuel Sarphati, who found their inspiration in Paris.

The end of the 19th century is sometimes called Amsterdam's second Golden Age. New museums, a train station, and the Concertgebouw were built. At this time the Industrial Revolution reached Amsterdam. The Amsterdam-Rhine Canal was dug to give Amsterdam a direct connection to the Rhine, and the North Sea Canal to give the port a shorter connection to the North Sea. Both projects improved communication with the rest of Europe and the world dramatically. Joseph Conrad gives a brief description of Amsterdam, seen from the sea at this period, in The Mirror of the Sea (1906).


Geography

Amsterdam fans out south from Amsterdam Centraal railway station. The main street is Damrak which leads into Rokin. The area to the east of Damrak is the oldest area and is known as de Wallen ("the walls") after the medieval walls of the city - this area contains the city's red light area. To the south of de Wallen is the old Jewish quarter of Waterlooplein. The 17th century girdle of concentric canals, known as the "grachtengordel", embraces the heart of the city. Beyond the grachtengordel are the formerly working class areas of Jordaan and de Pijp, Museumplein, containing the city's major museums, and Vondelpark, the 19th century park named after the Dutch writer Joost van den Vondel.

Several parts of the city and of the urban area are polders, recognisable by their postfix -meer meaning 'lake', such as Aalsmeer, Bijlmermeer, Haarlemmermeer, and Watergraafsmeer.


The canals

A woodcut (1885) of the Nieuwezijds Voorburgwal, a canal that is now a filled up
A typical view of Amsterdam canal, Feb 2008Much of the Amsterdam canal system is the successful outcome of city planning. In the early part of the 17th century, with immigration at a height, a comprehensive plan was put together, calling for four main, concentric half-circles of canals with their ends resting on de IJ bay. Known as the "grachtengordel", three of the canals are mostly for residential development (Herengracht or ‘’Gentleman's Canal’’; Keizersgracht or ‘’Emperor's Canal’’; and Prinsengracht or ‘’Prince's Canal’’), and a fourth, outer canal, the present Nassau/Stadhouderskade, for purposes of defense and water management. The plan also envisaged interconnecting canals along radii; a set of parallel canals in the Jordaan quarter (primarily for the transportation of goods, for example, beer); the conversion of an existing, inner perimeter canal (Singel) from a defensive purpose to residential and commercial development; and more than one hundred bridges. The defensive purpose of the Nassau/Stadhouderskade was served by moat and earthen dikes, with gates at transit points but otherwise no masonry superstructures.

Construction proceeded from west to east, across the breadth of the lay-out, like a gigantic windshield wiper as the historian Geert Mak calls it – not from the center outwards as a popular myth has it. Construction of the north-western sector was started in 1613. After 1656, with the canals in the southern sector also already finished for some time, building in that sector too was started, although slowly. The eastern part of the concentric canal plan, covering the area between the Amstel river and the IJ bay, was never implemented. In the following centuries, the land went mostly for parks, old age homes, theaters and other public facilities – and for waterways without much plan.

Over the years, several canals have been filled up and are now streets or squares, such as Nieuwezijds Voorburgwal and Spui.


Climate

Amsterdam enjoys a moderate temperate climate, with the weather patterns being strongly influenced by Amsterdam's proximity to the North Sea to the west and its prevailing north-western winds and gales. Winter temperatures are mild: on average above freezing, although frosts are not uncommon during spells of easterly or northeasterly winds blowing in from the inner European continent, i. e. from Scandinavia, Russia and even Siberia. Summers are warm but rarely hot. Days with measurable precipitation are common, but still Amsterdam averages less than 760 mm of precipitation annually. Most of it falls as protracted drizzle or light rain. But the occasional Western storm may bring a lot of water at once, and all of it has to be pumped out to higher ground and to the seas around the city. These bodies of water make cloudy and damp days common, particularly in cooler months, October through March.


Economy

New development on the south bank of the IJAmsterdam is the financial and business capital of the Netherlands and one of the most important cities in Europe in which to do business. Many large Dutch corporations and banks have their headquarters in Amsterdam, including ABN Amro, Akzo Nobel, Heineken International, ING Group, Ahold, TomTom, Delta Lloyd Group and Philips. KPMG International's global headquarters is located in nearby Amstelveen, as is the European headquarters of Cisco Systems.

Though many subsidiaries are located along the old canals, companies are increasingly relocating outside the city centre. The South Axis (Dutch: Zuidas) is increasingly a financial and legal center, and is intended to become the new business-face of the Netherlands.The five largest legal companies of the Netherlands have settled down in the South Axis, and also the Dutch subsidiaries of large consulting firms like Boston Consulting Group, McKinsey & Co and Accenture. In this financial quarter the recently expanded World trade centre also has its location.

The Amsterdam Stock Exchange (AEX), nowadays part of Euronext, is the world's oldest stock exchange and still one of the most important in Europe.


Tourism

Amsterdam is the 5th busiest tourist destination in Europe with more than 4.2 million international visitors. The room occupation rate is the 2nd highest in Europe in 2007. Tourists can choose from 350 Hotels, 17 of which are fivestar hotels. 18,000 rooms and almost 45,000 beds are provided.


Retail

Amsterdam shops range from large department stores such as Metz & Co, founded in 1740, Maison de Bonneterie a Parisian style store founded in 1889, and De Bijenkorf founded in 1870, to small specialty shops. The most luxurious shopping street is P.C. Hooftstraat, the busiest high street is Kalverstraat.


Demography

In the 16th and 17th century non-Dutch immigrants to Amsterdam were mostly Huguenots, Flemings, Sephardi Jews and Westphalians. Hugenots came after 1685's Edict of Fontainebleau, while the Flemish Protestants came during the Eighty Years' War. The Westphalians came to Amsterdam mostly for economic reasons – their influx continued through the 18th and 19th centuries.

The first mass immigrants in the 20th century were people from Indonesia, who came to Amsterdam after the independence of the Dutch East Indies in the 1940s and 1950s. In the 1960s guest workers from Turkey, Morocco, Italy and Spain migrated to Amsterdam. After the independence of Suriname in 1975 a large wave of Surinamese settled in Amsterdam, mostly in the Bijlmer area. Other immigrants, among which asylants and illegals, come from Europe, America, Asia and Africa. In the seventies and eighties many 'old' Amsterdammers moved to 'new' cities like Almere and Purmerend, prompted by the third planological bill of the Dutch government. This bill promoted suburbanization and arranged for new developments in so called "groeikernen", lit. "cores of growth". Young professionals and artists moved into neighbourhoods the Pijp and the Jordaan abandoned by these Amsterdammers. The non-Western immigrants settled mostly in the social housing projects in Amsterdam-West and the Bijlmer.


Culture

Rijksmuseum AmsterdamDuring the later part of the 16th century Amsterdams Rederijkerskamer (Chamber of Rhetoric) organized contests between different Chambers in the reading of poetry and drama. In 1638 Amsterdam got its first theatre. Ballet performances were given in this theatre as early as 1642. In the 18th century French theatre became popular. Opera could be seen in Amsterdam from 1677, first only Italian and French operas, but in the 18th century German operas. In the 19th century popular culture was centered around the Nes area in Amsterdam (mainly vaudeville and music-hall). The metronome, one of the most important advances in European classical music was invented here in 1812 by Dietrich Nikolaus Winkel. At the end of this century the Rijksmuseum and Gemeentelijk Museum were built. In 1888 the Concertgebouworkest was established. With the 20th century came cinema, radio and television. Though the studios are in Hilversum and Aalsmeer, Amsterdam's influence on programming is very strong.


Art

The artist most associated with Amsterdam is Rembrandt, whose work, and the work of his pupils, is displayed in the Rijksmuseum. Van Gogh lived in Amsterdam for a short while, so there is a museum dedicated to his early work.

Amsterdam has a world-class symphony orchestra, the Royal Concertgebouw Orchestra, the home base of which is the Concertgebouw.


Fashion

Amsterdam has developed itself into a European fashion capital. Big fashion brands like G-star,Gsus,BlueBlood,10 feet and Warmenhoven & Venderbos and fashion designers like Mart Visser Viktor & Rolf, Marlies Dekkers and Frans Molenaar are headquartered in Amsterdam. Also model agencies like Elite Models, Touche models and Tony Jones have opened departments in Amsterdam. Supermodels like Yfke Sturm, Doutzen Kroes and Kim Noorda started their career in Amsterdam. Amsterdam is also known for its World Fashion Centre.


Tourist attractions

Nearly a million people a year visit the Anne Frank House on the Prinsengracht.Visitors are attracted to Amsterdam for its reputation as a liberal city; its relaxed charm emphasised by elegant, narrow fronted merchant's houses and enchanting canals; and the reputation of its museums.

The major museums are the Rijksmuseum, the Stedelijk Museum, the Rembrandt House Museum, and the Van Gogh Museum, which houses the largest collection of Van Gogh's paintings and drawings in the world. The Anne Frank House, a museum dedicated to the story of Anne Frank, is also a popular tourist attraction.

The liberal nature of Amsterdam is not only physically embodied in the layout of the city, such as the de Wallen area which contains the red-light district and many cannabis-selling coffeeshops, but it is also embodied in the well-rounded, prevailing attitudes of its residents, government and businesses. Amsterdam's red-light district is located in the centre of the city and is clearly marked on maps. Window prostitution in the Netherlands is legal at specific places. Cannabis selling, however, is not - but it is tolerated when small quantities of cannabis (up to 5 grams) are involved.Previously in Amsterdam a handful of smart shops sold psilocybin mushrooms and drug paraphernalia. However psilocybin mushrooms have recently been made illegal. Though illegal to consume in public, these mushrooms are still sold by several smart shops.


Sports

Amsterdam is the hometown of Eredivisie football club Ajax. Its home base is the modern stadium Amsterdam ArenA, located in the south-east of the city.

In 1928, Amsterdam hosted the Games of the IXth Olympiad. The Olympic Stadium built for the occasion has been completely restored and is now used for cultural and sporting events, such as the Amsterdam Marathon.

Amsterdam also is home to a famous ice rink, the Jaap Eden baan. The Amstel Tijgers play in this arena in the Dutch ice hockey premier league. In speed skating many international championships have been fought in the 400-metre (1,310 ft) lane of this ice rink.

The city also has a baseball team, the Amsterdam Pirates, who play in the Dutch Major League. There are three field hockey teams, Amsterdam, Pinoke and Hurley, who play their matches around the Wagener Stadium. These teams are often referred to as playing in Amsterdam; however, all of them (even Amsterdam) play their matches in the neighbouring city of Amstelveen. There is also a basketball team, the Amsterdam Astronauts, who compete in the Dutch premier division and play their games in the Sporthallen Zuid, near the Olympic Stadium.

Since 1999 the city of Amsterdam has honoured its best sportsmen and -women at the Amsterdam Sports Awards. Boxer Raymond Joval and field hockey midfielder Carole Thate were the first to receive the awards in 1999.


Transportation

An Amsterdam bikeAmsterdam is one of the most bicycle-friendly cities in the world and is a centre of bicycle culture with good provision for cyclists such as bike paths and bike racks, which are ubiquitous throughout the city. There are an estimated one million bicycles in the city. However, bike theft is common, so cyclists use large secure locks.

In the city centre, driving a car is discouraged. Parking fees are steep and a great number of streets are closed to cars or are one-way.The local government sponsors carsharing and carpooling initiatives such as Autodelen and Meerijden.nu.

Public transport in Amsterdam mainly consists of bus and tram lines, operated by Gemeentelijk Vervoerbedrijf, Connexxion and Arriva; however, there are four metro lines; with a fifth line, the North/South line, under construction. Three free ferries carry pedestrians and cyclists across the IJ to Amsterdam-Noord, and two fare charging ferries go east and west along the harbour. There are also water taxis and a water bus, in addition to the canal cruises, that transport people along Amsterdam's waterways.

The A10 Ringroad surrounding the city connects Amsterdam with the Dutch national network of freeways. Interchanges on the A10 allow cars to enter the city by transferring to one of the eighteen city roads, numbered s101 through s118. These city roads are regional roads without grade separation, and sometimes without a central reservation. Most are accessible by cyclists. The s100 is called the centrumring, a smaller ringroad circumnavigating the city centre.

A tram on JavapleinAmsterdam is served by eight stations of the Nederlandse Spoorwegen (Dutch Railways). Five are intercity stops: Sloterdijk, Zuid, Amstel, Bijlmer ArenA and Amsterdam Centraal. Many other stations exist in the Amsterdam urban area.

Eurolines has coaches from Amsterdam to destinations all over Europe.

Amsterdam Centraal is an international train station. From the station there are regular services with destinations in Belgium, France, Germany, and Switzerland. Among these trains are international trains of the Nederlandse Spoorwegen and the Thalys, CityNightLine, and InterCityExpress.

Amsterdam Schiphol Airport is less than 20 minutes by train from Amsterdam Central Station. It is the biggest airport in the Netherlands, the fourth largest in Europe and the tenth largest in the world. It handles about 44 million passengers a year and is home base to KLM. Schiphol is the third busiest airport in the world measured by international passengers.

JXTA

I have been knowing JXTA since 2 years ago while I was studying P2P networks at AIT. At that time, I couldn't allocate my time to go through it. At present I need to work on it and, therefore, I spent my whole week on JXTA and played with the sample applications which use JXTA. Just few minutes ago, I took a quiz from Sun Microsystem's website. My score was more than 80 %. This indicates that my knowledge on JXTA is not so bad :). In this essay, I will focus the need of JXTA and discuss some of its features.

Traditional server client based applications have limitations. They can not serve to a large number of users. They are also vulnerable as they have a single point of failure, the server. P2P network can solve such limitations. Napster was the first P2P application in the internet which provided a P2P solution to share music files among peers. Although it was very popular, it had to shut down shortly after its lunch because of copyright infringement. However, it paved the way for P2P applications. Consequently, we can find very famous P2P applications e.g. skype in the current Internet.

Because of the key properties of P2P protocols many applications try to use the concepts. The concepts used by an application do not match with the concepts used by other application even if they provide the same features. For example, messages which are used to communicate among peers for yahoo chat application have completely different formats than those of MSN messenger. Some solution was needed to handle such issues. JXTA came up with the idea.

JXTA, also known as Juxtapose, is an open source peer-to-peer (P2P) protocol specification. The specification is prepared by Sun Microsystems in 2001. Remember that JXTA is specification. Thus it is platform independent. Its implementations can be found for Java, C, C++, C#.

Interesting feature of JXTA is that it can communicate with any peer or resource that are behing firewalls and NATs or use different transports. It forms an overlay network of peers. Each peer is identified by a unique ID, hash value of a URN ( ::= "urn:" ":" e.g. urn:ietf:rfc:2648, urn:isbn:0451450523). It means that peer can change the networks while keeping a constant identifier number.

As mentioned earlier, JXTA provides specification for building P2P networks. There are six protocols: Peer Resolver Protocol; Peer Information Protocol; Rendezvous Protocol; Peer Membership Protocol; Pipe Binding Protocol; Endpoint Routing Protocol. Furthermore, JXTA has two types of peers: Edge peers and Super Peers (Rendezvous Peer and Relay Peer). One peer can handle the role of all three peers. Super peer needs high resources like memory, and processing capacity. Furthermore, JXTA uses XML to send its messages. Pipes are used to communicate between two overlay peers.

References:
  1. Free JXTA Book
  2. Wikipedia
  3. JXTA Overview
  4. JXTA official site