Thursday, December 13, 2007

Teledesic Project Ended

Space News

PARIS — The Craig McCaw-backed Teledesic satellite broadband constellation project, which took the space industry by storm in the late 1990s and persuaded prospective contractors to invest about $1 billion in preparatory research, has surrendered its sole remaining asset.

In a letter to the U.S. Federal Communications Commission (FCC), the Bellevue, Wash., company said it was giving up its license to use a massive swath of radio spectrum — 500 megahertz uplink, and 500 megahertz downlink.

At just three paragraphs, the June 27 letter from Teledesic’s lawyer, Mark A. Grannis, is as short and clear as the Teledesic story is long and complicated.

Why Teledesic decided to make the move now is unclear. The company has been little more than a shell for at least a year, and its would-be contractors had long since stopped working on the project.

From its beginnings in 1991 and its formal FCC application in 1994, Teledesic evolved from a system proposing a low-orbiting constellation of 840 satellites, to one with 288 satellites, and finally to a medium Earth orbit constellation of 30 satellites.

Grannis, a partner in the Washington law firm of Harris, Wiltshire & Grannis LLP, said the decision to abandon all claims on the radio spectrum was made in part because Teledesic was facing a January 2004 FCC deadline to show firm progress in building its satellites.

"In the current funding environment, that was not going to be possible," Grannis said in a July 11 interview. "Teledesic was a magnificent dream, and I was a true believer all along — one of the last true believers."

International frequency regulations assign licenses to nations, not to companies. The licensed administration then sorts out which company has access. With Teledesic abandoning its rights, FCC officials now are mulling whether to return the frequencies to the common global pool managed by the International Telecommunication Union (ITU), a United Nations affiliate based in Geneva.

"We’re still looking at this to determine what to do," said an FCC official July 11. "It might be better just to let the license expire. At this point, does anybody care about it? We want to find out. We have other applicants that want to use this spectrum."

But the FCC official acknowledged that the other applicants, while alive in a regulatory sense, have shown no recent motivation to develop their systems. Ironically, the week after Teledesic’s letter to the FCC, the agency issued a broad order setting out its proposal for how Teledesic would share its frequencies with the several other satellite-broadband proposals that had applied for the spectrum in a second round of applications. Teledesic was the lone licensee in the first round.

The FCC official said that order, dated July 9, was issued despite the Teledesic decision because it has value as a precedent for settling future conflicts between first-round licensees and second-round applicants for spectrum.

"We’re going to do an honest evaluation," the FCC official said. "For now, as far as we’re concerned the other applicants have not informed us that they are no longer interested."

At the height of its reputation, Teledesic marshaled the lobbying power of the U.S. government to persuade other governments to grant the company access to its radio frequencies. Several European governments feared that Teledesic, which for a time also appeared to have the support of Microsoft Chairman Bill Gates, would create a global broadband monopoly.

"Some of the delegates to those (ITU) meetings might feel like they are owed an apology for all the work they put in," Grannis said. "But we really believed it would have been a good system for the world. Still, you can’t blame the investors in Teledesic now for not wanting to walk off a cliff."

Teledesic Project

Teledesic Corporation was a company founded in the 1990s to build a commercial broadband satellite constellation for Internet services. The goal of the Teledesic system was to provide a telecommunications infrastructure composed of low-earth-orbit satellites, for use by millions of concurrent Internet users, providing uplinks of as much as 100 Mbit/second and downlinks of up to 720 Mbit/second, using small, fixed, VSAT-type antennas, and completely bypassing terrestrial networks. The original 1995 proposal was extremely ambitious, costing over US$9 billion originally planning 840 active satellites with in-orbit spares at an altitude of 700 km. In 1997 the scheme was scaled back to 288 active satellites at 1400 km and was later scaled back further in complexity and number of satellites as the projected market demand continued to decrease.

The commercial failure of the similar Iridium and Globalstar ventures (composed of 66 and 48 operational satellites, respectively) and other systems, along with bankruptcy protection filings, were primary factors in halting the project, and Teledesic officially suspended its satellite construction work on October 1, 2002.

Teledesic was notable for gaining early funding from Microsoft (investing US$30 million for an 8.5% stake), Craig McCaw, Bill Gates, Paul Allen and Saudi prince Alwaleed bin Talal, and for achieving allocation on the Ka-band frequency spectrum for non-geostationary services. Teledesic's merger with ICO Global Communications led to McCaw's companies taking control of ICO, which has successfully launched one test satellite.

Tuesday, November 27, 2007

ASP.NET / C#.NET / Authentication & Authorisation

Authentication & authorization:-

If you are beginner in web applications, then this is right time to feed the following topic.

Suppose you are going to develop a website (in ASP.NET), where there must be a process of authentication & authorization (authentication means that the user is valid or not & authorization means how much resources an authenticated user will enjoy).

There should be 3 types of users in your website:-

1. 1. Anonymous user
2.
General user
3.
Administrator

When an anonymous user requests for home page, following page will come(Login.aspx)


They can only view the website’s limited resources.



If he/she provide user name & password, then they will be authenticated users & the following page will be displayed(Default.aspx)

There will be Sign out option as they are logged in.



Again if they click in Sign out option, they get following page again (Login.aspx)

If anyone access website with Admin password, then following page (Default.aspx) will come with Sign out option & various more options exclusively unique for Administrator





The codes are very simple, try to understand the underlying technology.

You think in this way, that users are requesting for the home page (Default.aspx). If page is not authenticated then users get the Login.aspx page & users will see Login.aspx page as home page.

Codes under Default.aspx ,

protected void Page_Load(object sender, EventArgs e)

{

if (!Page.User.Identity.IsAuthenticated)

{

Server.Transfer("login.aspx");

}

else

{

lblStatus.Text = User.Identity.Name;

if (Page.User.IsInRole("adminrole"))

{

btnAdmin.Visible = true;

btnUpload_books.Visible = true;

btnUpload_papers.Visible = true;

btnCk_payments.Visible = true;

}

}

}

Codes under Login.aspx ,

using System.Data;

using System.Data.SqlClient;

string s1;

SqlConnection sqlCon;

SqlCommand command;

SqlDataReader reader;

protected void Page_Load(object sender, EventArgs e)

{

s1 = System.Configuration.ConfigurationManager.AppSettings.Get("con1");

sqlCon = new SqlConnection();

sqlCon.ConnectionString = s1;

}

protected void btnLogin_Click(object sender, EventArgs e)

{

if (sqlCon.State == ConnectionState.Open)

sqlCon.Close();

sqlCon.Open();

command = new SqlCommand();

command.Connection = sqlCon;

command.CommandType = System.Data.CommandType.StoredProcedure;

command.CommandText = "user_select";

command.Parameters.Add("@uid", System.Data.SqlDbType.VarChar, 20);

command.Parameters["@uid"].Value = txtUname.Text.ToString();

reader = command.ExecuteReader();

if (reader.Read())

{

if (reader["upasswd"].ToString() == txtUpasswd.Text.ToString())

{

FormsAuthentication.RedirectFromLoginPage(txtUname.Text, false);

}

else

{

lblWarn.Text = "Invalid Credentials; Please Try again";

}

}

}

Codes under web.config ,

<authentication mode="Forms">

<forms name="login" loginUrl="login.aspx" protection="All" timeout="30" />

authentication>

<authorization>

<allow users="admin"/>

<allow roles="adminrole"/>

<deny users="?"/>

authorization>

<anonymousIdentification enabled="true"/>

<roleManager enabled="true"/>

N.B. :- Here I have used name of Administrator ‘Admin’, if you like to give other name then write your own given name in tag.

Thank You…………….

Mail me at : partho.neo@gmail.com / partho.neo@indiatimes.com



Thursday, November 22, 2007

Netbeans vs Eclipse

Eclipse vs NetBeans ...On which side are you on? Let us know which IDE you think is better and why.

Think of Java IDEs and two names that will come up are Eclipse and NetBeans. I have been using NetBeans for many years now and Eclipse has been a more recent addition to my Java armory. I have enjoyed working with both tools and as such don't have a clear favorite. I prefer NetBeans a little more than Eclipse as I have been using it longer and am more comfortable with it.

The thing I am most surprised about is how rapidly Eclipse has grown and how it has well and truly eclipsed NetBeans over the past year or so.

In the article: Migrating to Eclipse: A developer's guide to evaluating Eclipse vs. Netbeans, the author shows the differences between the two IDEs.

Just Eclipse or Eclipse in its WSAD avatar or MyEclipseIDE avatar is definitely good but hey..is it so good that nobody wants to be talk of NetBeans these days??? I haven't as yet tried out the new NetBeans 5.5 but I do hope it is very good. So that the competition between Eclipse and NetBeans stays fierce and there is no clear winner.

The end user gets two very good IDEs.

Java IDE comparison: Borland JBuilder Top

A comparison of 4 Java IDEs, from Borland, IBM, Oracle and Sun ranks them as follows:
  • Borland JBuilder 2005 Enterprise tops with - ( 8.5 / 10 )
  • IBM Rational Software Architect 6.0 - ( 8.3 / 10 )
  • Oracle JDeveloper 10.1.3 - ( 8 / 10 )
  • Sun Java Studio Enterprise 7 - ( 7.4 / 10 )


The article evaluates the four IDEs based on Features, Ease-of-use, Integration, Performance and Value.

To get more info click here