March 2009 ~ ADVANCE C PROGRAMMING

Sunday, March 15, 2009

2003

11:43 PM wildrank Comments (0)

In November 2003, Ben and Adam Laurie from A.L. Digital Ltd. discovered that serious flaws in Bluetooth security may lead to disclosure of personal data.[26] It should be noted, however, that the reported security problems concerned some poor implementations of Bluetooth, rather than the protocol itself.In a subsequent experiment, Martin Herfurt from the trifinite.group was able to do a field-trial at the CeBIT fairgrounds, showing the importance of the problem to the world. A new attack called BlueBug was used for this experiment.[27] This is one of a number of concerns that have been raised over the security of Bluetooth communicatio...

2004

11:42 PM wildrank Comments (0)

In 2004 the first purported virus using Bluetooth to spread itself among mobile phones appeared on the Symbian OS.[28] The virus was first described by Kaspersky Lab and requires users to confirm the installation of unknown software before it can propagate. The virus was written as a proof-of-concept by a group of virus writers known as "29A" and sent to anti-virus groups. Thus, it should be regarded as a potential (but not real) security threat to Bluetooth or Symbian OS since the virus has never spread in the wild.In August 2004, a world-record-setting experiment (see also Bluetooth sniping) showed that the range of Class 2 Bluetooth radios...

2005

11:41 PM wildrank Comments (0)

In January 2005, a mobile malware worm known as Lasco.A began targeting mobile phones using Symbian OS (Series 60 platform) using Bluetooth-enabled devices to replicate itself and spread to other devices. The worm is self-installing and begins once the mobile user approves the transfer of the file (velasco.sis ) from another device. Once installed, the worm begins looking for other Bluetooth-enabled devices to infect. Additionally, the worm infects other .SIS files on the device, allowing replication to another device through use of removable media (Secure Digital, Compact Flash, etc.). The worm can render the mobile device unstable.[30]In April...

2006

11:39 PM wildrank Comments (0)

In April 2006, researchers from Secure Network and F-Secure published a report that warns of the large number of devices left in a visible state, and issued statistics on the spread of various Bluetooth services and the ease of spread of an eventual Bluetooth wo...

2007

11:38 PM wildrank Comments (0)

In October 2007, at the Luxemburgish Hack.lu Security Conference, Kevin Finistere and Thierry Zoller demonstrated and released a remote root shell via Bluetooth on Mac OS X v10.3.9 and v10.4. They also demonstrated the first Bluetooth PIN and Linkkeys cracker, which is based on the research of Wool and Shak...

Health concerns

11:35 PM wildrank Comments (0)

Main article: Wireless electronic devices and healthBluetooth uses the microwave radio frequency spectrum in the 2.4 GHz to 2.4835 GHz range. Maximum power output from a Bluetooth radio is 100 mW, 2.5 mW, and 1 mW for Class 1, Class 2, and Class 3 devices respectively, which puts Class 1 at roughly the same level as mobile phones, and the other two classes much lower.[35] Accordingly, Class 2 and Class 3 Bluetooth devices are considered less of a potential hazard than mobile phones, and Class 1 may be comparable to that of mobile pho...

Code division multiple access (CDMA)

11:33 PM wildrank Comments (0)

Code division multiple access (CDMA) is a channel access method utilized by various radio communication technologies. It should not be confused with the mobile phone standards called cdmaOne and CDMA2000 (which are often referred to as simply "CDMA"), this uses CDMA as an underlying channel access method.One of the basic concepts in data communication is the idea of allowing several transmitters to send information simultaneously over a single communication channel. This allows several users to share a bandwidth of frequencies. This concept is called multiplexing. CDMA employs spread-spectrum technology and a special coding scheme (where each...

Uses

11:32 PM wildrank Comments (0)

* One of the early applications for code division multiplexing—predating, and distinct from cdmaOne—is in GPS. * The Qualcomm standard IS-95, marketed as cdmaOne. * The Qualcomm standard IS-2000, known as CDMA2000. This standard is used by several mobile phone companies, including the Globalstar satellite phone network. * CDMA has been used in the OmniTRACS satellite system for transportation logisti...

Steps in CDMA Modulation

11:30 PM wildrank Comments (0)

CDMA is a spread spectrum multiple access[1] technique. A spread spectrum technique is one which spreads the bandwidth of the data uniformly for the same transmitted power. Spreading code is a pseudo-random code which has a narrow Ambiguity function unlike other narrow pulse codes. In CDMA a locally generated code runs at a much higher rate than the data to be transmitted. Data for transmission is simply logically XOR (exclusive OR) added with the...

Code Division Multiplexing (Synchronous CDMA)

11:16 PM wildrank Comments (0)

Synchronous CDMA exploits mathematical properties of orthogonality between vectors representing the data strings. For example, binary string "1011" is represented by the vector (1, 0, 1, 1). Vectors can be multiplied by taking their dot product, by summing the products of their respective components. If the dot product is zero, the two vectors are said to be orthogonal to each other. (Note: If u=(a,b) and v=(c,d), the dot product u.v = a*c + b*d)...

Example

11:09 PM wildrank Comments (0)

Start with a set of vectors that are mutually orthogonal. (Although mutual orthogonality is the only condition, these vectors are usually constructed for ease of decoding, for example columns or rows from Walsh matrices.) An example of orthogonal functions is shown in the picture on the left. These vectors will be assigned to individual users and are called the "code", "chipping code" or "chip code". In the interest of brevity, the rest of this example...

Asynchronous CDMA

11:08 PM wildrank Comments (0)

ee also: Direct-sequence spread spectrumThe previous example of orthogonal Walsh sequences describes how 2 users can be multiplexed together in a synchronous system, a technique that is commonly referred to as Code Division Multiplexing (CDM). The set of 4 Walsh sequences shown in the figure will afford up to 4 users, and in general, an NxN Walsh matrix can be used to multiplex N users. Multiplexing requires all of the users to be coordinated so that each transmits their assigned sequence v (or the complement, -v) starting at exactly the same time. Thus, this technique finds use in base-to-mobile links, where all of the transmissions originate...

Advantages of Asynchronous CDMA over other techniques

11:06 PM wildrank Comments (0)

1. Efficient Practical utilization of Fixed Frequency SpectrumAsynchronous CDMA's main advantage over CDM (Synchronous CDMA), TDMA and FDMA is that it can use the spectrum more efficiently in mobile telephony applications. (In theory, CDMA, TDMA and FDMA have exactly the same spectral efficiency but practically, each has its own challenges - power control in the case of CDMA, timing in the case of TDMA, and frequency generation/filtering in the case of FDMA.) TDMA systems must carefully synchronize the transmission times of all the users to ensure that they are received in the correct timeslot and do not cause interference. Since this cannot...

Spread Spectrum Characteristics of CDMA

11:05 PM wildrank Comments (0)

Most modulation schemes try to minimize the bandwidth of this signal since bandwidth is a limited resource. However, spread spectrum techniques use a transmission bandwidth that is several orders of magnitude greater than the minimum required signal bandwidth. One of the initial reasons for doing this was military applications including guidance and communication systems. These systems were designed using spread spectrum because of its security and resistance to jamming. Asynchronous CDMA has some level of privacy built in because the signal is spread using a pseudorandom code; this code makes the spread spectrum signals appear random or have...

GPRS Core Network

10:49 PM wildrank Comments (0)

he General Packet Radio Service (GPRS) system is used by GSM mobile phones, the most common mobile phone system in the world (as of 2004[update]), for transmitting IP packets. The GPRS core network is the centralized part of the GPRS system. It also provides support for WCDMA based 3G networks. The GPRS core network is an integrated part of the GSM network switching subsystem.General support functionsGPRS core structureThe GPRS core network provides...

General packet radio service (GPRS)

10:44 PM wildrank Comments (0)

General packet radio service (GPRS) is a packet oriented mobile data service available to users of the 2G cellular communication systems global system for mobile communications (GSM), as well as in the 3G systems. In the 2G systems, GPRS provides data rates of 56-114 kbit/s.GPRS data transfer is typically charged per megabyte of traffic transferred, while data communication via traditional circuit switching is billed per minute of connection time,...

Gearing Up for the Big Switch

2:27 AM wildrank Comments (0)

By LISA NAPOLIPublished: Thursday, November 13, 2003 * Sign In to E-Mail * Print * Single-Page * Reprints * ShareClose o Linkedin o Digg o Facebook o Mixx o My Space o Yahoo! Buzz o PermalinkoArticle Tools Sponsored ByGUY RADER lives in Queens, but when it comes to cellphone service, he feels as if he has been ''in pre-glasnost Russia.''That is because he has not been able to switch wireless companies without giving up his number, which he has had for four years. But in 11 days, new federal rules will let him move his number from Sprint to a new provider, so he...

tata neno picture

2:08 AM wildrank Comments (0)

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Tata Motors Will Launch Nano With Micro-Hybrid Version In India

10:18 PM wildrank Comments (0)

Tata Motors is currently working on launching the world’s cheapest, People’s car on a micro-hybrid version to increase the fuel efficiency to cut down its emission.Tata Motors is currently discussing with Bosch, the world’s biggest component supplier, for sourcing the technology that is already being used by Mahindra & Mahindra in India and other automak...

Cheapest Car in the World:TATA NANO: only 2500$

10:01 PM wildrank Comments (0)

Hello everyone, Although this is a off topic post on this blog, but i cant keep myself in control about not to posting this news. Today here in Auto EXPO Delhi (India) Tata motors launched worlds cheapest ever car named as "TATA NENO" When this project started 3 years back, everyone in world says "THIS IS IMPOSSIBLE TO DO". Now Tata motors have created a history by launching the car. Here are quick specifications: Engine: 625 CC (4 gear manual transmission)...

Standards

2:13 AM wildrank Comments (0)

There are several standards documents covering the physical encoding of QR Code:[1] * October 1997 — AIM International ISS QR Code * January 1999 — JIS X 0510 * June 2000 — ISO/IEC 18004:2000 Information technology — Automatic identification and data capture techniques — Bar code symbology — QR Code (now withdrawn) Defines QR Code Model 1 and QR Code Model 2 symbols. * 1 September 2006 — ISO/IEC 18004:2006 Information technology...

Overview

2:11 AM wildrank Comments (0)

Although initially used for tracking parts in vehicle manufacturing, QR Codes are now used in a much broader context, including both commercial tracking applications and convenience-oriented applications aimed at mobile phone users (known as mobile tagging). QR Codes storing addresses and URLs may appear in magazines, on signs, buses, business cards or just about any object that users might need information about. Users with a camera phone equipped...

QR Code

2:08 AM wildrank Comments (0)

A QR Code is a matrix code (or two-dimensional bar code) created by Japanese corporation Denso-Wave in 1994. The "QR" is derived from "Quick Response", as the creator intended the code to allow its contents to be decoded at high speed. QR Codes are common in Japan, where they are currently the most popular type of two dimensional codes. Moreover, most current Japanese mobile phones can read this code with their came...

Japan, EU to jointly develop eco-friendly technologies

12:33 AM wildrank Comments (0)

TOKYO — Japan has decided to work with the European Union to develop next-generation photovoltaic technologies as part of their efforts to combat climate change, industry ministry officials said Friday. Japan and the European Union will cooperate in developing photovoltaic cells that would be 40 percent more efficient in power generation but cost about one-sixth of the current average price of 46 yen per kilowatt hour, the officials said.The other areas in which Japan and the European Union will launch joint development projects are related to rechargeable batteries, and carbon capture and storage technologies, they said. As to batteries for...

Science, engineering and technology

12:22 AM wildrank Comments (0)

The distinction between science, engineering and technology is not always clear. Science is the reasoned investigation or study of phenomena, aimed at discovering enduring principles among elements of the phenomenal world by employing formal techniques such as the scientific method.[8] Technologies are not usually exclusively products of science, because they have to satisfy requirements such as utility, usability and safety.Engineering is the goal-oriented process of designing and making tools and systems to exploit natural phenomena for practical human means, often (but not always) using results and techniques from science. The development...

Technology

12:16 AM wildrank Comments (0)

From Wikipedia, the free encyclopediaJump to: navigation, searchSemi-protected"Advanced technology" redirects here. For the Advanced Technology form factor, see AT (form factor).By the mid 20th century, humans had achieved a mastery of technology sufficient to leave the atmosphere of the Earth for the first time and explore space.Technology is a broad concept that deals with an animal species' usage and knowledge of tools and crafts, and how it affects...

WiMAX

9:13 PM wildrank Comments (1)

WiMAXFrom Wikipedia, the free encyclopediaJump to: navigation, search This article may require copy-editing for grammar, style, cohesion, tone or spelling. You can assist by editing it now. A how-to guide is available. (August 2008)The Internet Protocol SuiteApplication LayerBGP · DHCP · DNS · FTP · GTP · HTTP · IMAP · IRC · Megaco · MGCP · NNTP · NTP · POP · RIP · RPC · RTP · RTSP · SDP · SIP · SMTP · SNMP · SOAP · SSH · STUN · Telnet · TLS/SSL...