Core Networking

Difference between 2G - 3G - 4G & What is 4G & its Advantages ?

noreply@blogger.com (Manpreet Singh Bindra) — Wed, 29 Mar 2017 18:00:00 +0000

This is how technology is improving.

4G is stand for ‘Fourth Generation’, it is a wireless network system or packet switched wireless system with extensive area exposure & soaring throughput. It is intended to be cost efficient & to supply high phantom effectiveness. The data rate or velocity of 20Mbps is working. The mobile velocity will be up to ‘200Km/Hr’ & the elevated presentation is accomplished by the utilization of extensive term channel in both instance term channel in both instance & occurrence, preparation among users.

Advantages:

It speedily downloads the files over wireless network system or form.
Particularly elevated voice excellence.
It can simply reach Internet, Instant Messaging (IM), common networks, video calling, and many more things.
It continues connected to the Internet devoid of any disturbance.
It has simpler approach to the services & consumption.

Internet and its Component

noreply@blogger.com (Manpreet Singh Bindra) — Sun, 22 Jul 2012 15:26:00 +0000

The internet is a computer network made up of thousands of networks worldwide. No one knows exactly how many computers are connected to the Internet. It is certain, however, that these number in the millions.

No one is in charge of the Internet. There are organizations which develop technical aspects of this network and set standards for creating applications on it, but no governing body is in control. The Internet backbone, through which Internet traffic flows, is owned by private companies.

All computers on the Internet communicate with one another using the Transmission Control Protocol/Internet Protocol suite, abbreviated to TCP/IP. Computers on the Internet use a client /server architecture. This means that the remote server machine provides files and services to the user's local client machine. Software can be installed on a client computer to take advantage of the latest access technology.

An Internet user has access to a wide variety of services: electronic mail, file transfer, vast information resources, interest group membership, interactive collaboration, multimedia displays, real-time broadcasting, shopping opportunities, breaking news, and much more.

The Internet consists primarily of a variety of access protocols. Many of these protocols feature programs that allow users to search for and retrieve material made available by the protocol.

COMPONENTS OF THE INTERNET

WORLD WIDE WEB

The World Wide Web (abbreviated as the Web or WWW) is a system of Internet servers that supports hypertext to access several Internet protocols on a single interface. Almost every protocol type available on the Internet is accessible on the Web. This includes e-mail, FTP, Telnet, and Usenet News. In addition to these, the World Wide Web has its own protocol: HyperText Transfer Protocol, or HTTP. These protocols will be explained later in this document.

The World Wide Web provides a single interface for accessing all these protocols. This creates a convenient and user-friendly environment. It is no longer necessary to be conversant in these protocols within separate, command-level environments. The Web gathers together these protocols into a single system. Because of this feature, and because of the Web's ability to work with multimedia and advanced programming languages, the Web is the fastest-growing component of the Internet.

The operation of the Web relies primarily on hypertext as its means of information retrieval. HyperText is a document containing words that connect to other documents. These words are called links and are selectable by the user. A single hypertext document can contain links to many documents. In the context of the Web, words or graphics may serve as links to other documents, images, video, and sound. Links may or may not follow a logical path, as each connection is programmed by the creator of the source document. Overall, the Web contains a complex virtual web of connections among a vast number of documents, graphics, videos, and sounds.

Producing hypertext for the Web is accomplished by creating documents with a language called HyperText Markup Language, or HTML. With HTML, tags are placed within the text to accomplish document formatting, visual features such as font size, italics and bold, and the creation of hypertext links. Graphics and multimedia may also be incorporated into an HTML document. HTML is an evolving language, with new tags being added as each upgrade of the language is developed and released. The World Wide Web Consortium (W3C), led by Web founder Tim Berners-Lee, coordinates the efforts of standardizing HTML. The W3C now calls the language XHTML and considers it to be an application of the XML language standard.

The World Wide Web consists of files, called pages or home pages, containing links to documents and resources throughout the Internet.

The Web provides a vast array of experiences including multimedia presentations, real-time collaboration, interactive pages, radio and television broadcasts, and the automatic "push" of information to a client computer. Programming languages such as Java, JavaScript, Visual Basic, Cold Fusion and XML are extending the capabilities of the Web. A growing amount of information on the Web is served dynamically from content stored in databases. The Web is therefore not a fixed entity, but one that is in a constant state of development and flux.

For more complete information about the World Wide Web, see Understanding The World Wide Web.

E-MAIL

Electronic mail, or e-mail, allows computer users locally and worldwide to exchange messages. Each user of e-mail has a mailbox address to which messages are sent. Messages sent through e-mail can arrive within a matter of seconds.

A powerful aspect of e-mail is the option to send electronic files to a person's e-mail address. Non-ASCII files, known as binary files, may be attached to e-mail messages. These files are referred to as MIME attachments.MIME stands for Multimedia Internet Mail Extension, and was developed to help e-mail software handle a variety of file types. For example, a document created in Microsoft Word can be attached to an e-mail message and retrieved by the recipient with the appropriate e-mail program. Many e-mail programs, including Eudora, Netscape Messenger, and Microsoft Outlook, offer the ability to read files written in HTML, which is itself a MIME type.

TELNET

Telnet is a program that allows you to log into computers on the Internet and use online databases, library catalogs, chat services, and more. There are no graphics in Telnet sessions, just text. To Telnet to a computer, you must know its address. This can consist of words (locis.loc.gov) or numbers (140.147.254.3). Some services require you to connect to a specific port on the remote computer. In this case, type the port number after the Internet address. Example: telnet nri.reston.va.us 185.

Telnet is available on the World Wide Web. Probably the most common Web-based resources available through Telnet have been library catalogs, though most catalogs have since migrated to the Web. A link to a Telnet resource may look like any other link, but it will launch a Telnet session to make the connection. A Telnet program must be installed on your local computer and configured to your Web browser in order to work.

With the increasing popularity of the Web, Telnet has become less frequently used as a means of access to information on the Internet.

FTP

FTP stands for File Transfer Protocol. This is both a program and the method used to transfer files between computers. Anonymous FTP is an option that allows users to transfer files from thousands of host computers on the Internet to their personal computer account. FTP sites contain books, articles, software, games, images, sounds, multimedia, course work, data sets, and more.

If your computer is directly connected to the Internet via an Ethernet cable, you can use one of several PC software programs, such as WS_FTP for Windows, to conduct a file transfer.

FTP transfers can be performed on the World Wide Web without the need for special software. In this case, the Web browser will suffice. Whenever you download software from a Web site to your local machine, you are using FTP. You can also retrieve FTP files via search engines such as FtpFind, located at /http://www.ftpfind.com/. This option is easiest because you do not need to know FTP program commands.

E-MAIL DISCUSSION GROUPS

One of the benefits of the Internet is the opportunity it offers to people worldwide to communicate via e-mail. The Internet is home to a large community of individuals who carry out active discussions organized around topic-oriented forums distributed by e-mail. These are administered by software programs. Probably the most common program is the listserv.

A great variety of topics are covered by listservs, many of them academic in nature. When you subscribe to a listserv, messages from other subscribers are automatically sent to your electronic mailbox. You subscribe to a listserv by sending an e-mail message to a computer program called a listserver. Listservers are located on computer networks throughout the world. This program handles subscription information and distributes messages to and from subscribers. You must have a e-mail account to participate in a listserv discussion group. Visit Tile.net at /http://tile.net/ to see an example of a site that offers a searchablecollection of e-mail discussion groups.

Majordomo and Listproc are two other programs that administer e-mail discussion groups. The commands for subscribing to and managing your list memberships are similar to those of listserv.

USENET NEWS

Usenet News is a global electronic bulletin board system in which millions of computer users exchange information on a vast range of topics. The major difference between Usenet News and e-mail discussion groups is the fact that Usenet messages are stored on central computers, and users must connect to these computers to read or download the messages posted to these groups. This is distinct from e-mail distribution, in which messages arrive in the electronic mailboxes of each list member.

Usenet itself is a set of machines that exchanges messages, or articles, from Usenet discussion forums, called newsgroups. Usenet administrators control their own sites, and decide which (if any) newsgroups to sponsor and which remote newsgroups to allow into the system.

There are thousands of Usenet newsgroups in existence. While many are academic in nature, numerous newsgroups are organized around recreational topics. Much serious computer-related work takes place in Usenet discussions. A small number of e-mail discussion groups also exist as Usenet newsgroups.

The Usenet newsfeed can be read by a variety of newsreader software programs. For example, the Netscape suite comes with a newsreader program called Messenger. Newsreaders are also available as standalone products.

FAQ, RFC, FYI

FAQ stands for Frequently Asked Questions. These are periodic postings to Usenet newsgroups that contain a wealth of information related to the topic of the newsgroup. Many FAQs are quite extensive. FAQs are available by subscribing to individual Usenet newsgroups. A Web-based collection of FAQ resources has been collected by The Internet FAQ Consortium and is available at /http://www.faqs.org/.

RFC stands for Request for Comments. These are documents created by and distributed to the Internet community to help define the nuts and bolts of the Internet. They contain both technical specifications and general information.

FYI stands for For Your Information. These notes are a subset of RFCs and contain information of interest to new Internet users.

Links to indexes of all three of these information resources are available on the University Libraries Web site at /http://library.albany.edu/reference/faqs.html.

CHAT & INSTANT MESSENGING

Chat programs allow users on the Internet to communicate with each other by typing in real time. They are sometimes included as a feature of a Web site, where users can log into the "chat room" to exchange comments and information about the topics addressed on the site. Chat may take other, more wide-ranging forms. For example, America Online is well known for sponsoring a number of topical chat rooms.

Internet Relay Chat (IRC) is a service through which participants can communicate to each other on hundreds of channels. These channels are usually based on specific topics. While many topics are frivolous, substantive conversations are also taking place. To access IRC, you must use an IRC software program.

A variation of chat is the phenomenon of instant messenging. With instant messenging, a user on the Web can contact another user currently logged in and type a conversation. Most famous is America Online's Instant Messenger. ICQ, MSN and Yahoo are other commonly-used chat programs.

Other types of real-time communication are addressed in the tutorial Understanding the World Wide Web.

MUD/MUSH/MOO/MUCK/DUM/MUSE

MUD stands for Multi User Dimension. MUDs, and their variations listed above, are multi-user virtual reality games based on simulated worlds. Traditionally text based, graphical MUDs now exist. There are MUDs of all kinds on the Internet, and many can be joined free of charge. For more information, read one of the FAQs devoted to MUDs available at the FAQ site at

Politics at Workplace: Evil or Beneficial?

noreply@blogger.com (Manpreet Singh Bindra) — Sat, 05 May 2012 19:28:00 +0000

Avoiding politics at workplace
Although it is practically impossible to make your workplace free from the politics, but the organisation and the employees can follow certain ethics for themselves to make their workplace healthier:

Avoid distorting or manipulating the truth and the facts.
Be yourself. Don’t have different faces to suit different people and different situations.
Be fair in your dealings. Take decisions based on other’s performance and not on the basis of your relations with them.
Be flexible, approachable and accessible to others. Rigidity can isolate you.
Communicate – Lack of proper communication is the root cause of most of the problems. Therefore, ensure a timely and open communication system. Hiding information, rumors or distorted information can aggravate the situation and problem. Proper communication will also help to combat the effect of gossip.
Have a broader perspective. Don’t work to satisfy your ego every time. Give a fair chance to everyone to put forward their thoughts.
Last but not the least; be clear in your conscious. Don’t compromise on your morals and ethics and, don’t hesitate to apologize if you realize that you are wrong.

Multi-Core Processing

noreply@blogger.com (Manpreet Singh Bindra) — Sun, 11 Mar 2012 11:12:00 +0000

Multi-core processing is a disruptive technology. Network packets can be processed much more efficiently with multi-core systems, but only if software is carefully optimized.Existing networking stacks will not perform well in multi-core environments; a new paradigm is needed to harness the potential of multi-core networking. Expertise is required in processor device programming, operating systems internals, and networking internals. Remember, two out of three isn’t good enough.

Today multi-core packet processing is utilized in edge, aggregation, and core devices where multi-gigabit performance is required. But multi-core packet processing promises to bring performance enhancements to the entire range of networking devices, from the core to end user.

Pressure Swing Adsorption(PSA)

noreply@blogger.com (Manpreet Singh Bindra) — Sat, 02 Apr 2011 14:50:00 +0000

PSA (Pressure Swing Adsorption) technology permits producing oxygen by pressurization with low-pressure compressed air of two towers filled with zeolite molecular sieve in cyclic alternation. While one of the towers is in adsorption phase, the other one is regenerated by reducing the pressure.

Business Strategy for Growth

noreply@blogger.com (Manpreet Singh Bindra) — Sun, 20 Feb 2011 18:51:00 +0000

Business strategy depend on whether it markets new or existing products in new or existing markets.

Result from Ansoff Model

Market penetration

• Maintain or increase the market share of current products – this can be achieved by a combination of competitive pricing strategies, advertising, sales promotion and perhaps more resources dedicated to personal selling

• Secure dominance of growth markets

• Restructure a mature market by driving out competitors; this would require a much more aggressive promotional campaign, supported by a pricing strategy designed to make the market unattractive for competitors

• Increase usage by existing customers – for example by introducing loyalty schemes
A market penetration marketing strategy is very much about “business as usual”. The business is focusing on markets and products it knows well. It is likely to have good information on competitors and on customer needs. It is unlikely, therefore, that this strategy will require much investment in new market research.

Market development

• New geographical markets; for example exporting the product to a new country

• New product dimensions or packaging: for example

• New distribution channels

• Different pricing policies to attract different customers or create new market segments

Product development

This strategy may require the development of new competencies and requires the business to develop modified products which can appeal to existing markets.

Diversification

This is an inherently more risk strategy because the business is moving into markets in which it has little or no experience.

Long Term Evolution (LTE)

noreply@blogger.com (Manpreet Singh Bindra) — Fri, 18 Feb 2011 10:46:00 +0000

Talking about Long Term Evolution (LTE) ,it is a 4G wireless broadband technology developed by the Third Generation Partnership Project (3GPP).

"Long Term Evolution" because it represents the next step (4G) in a progression from GSM, a 2G standard, to UMTS, the 3G technologies based upon GSM. LTE provides significantly increased peak data rates, with the potential for 100 Mbps downstream and 30 Mbps upstream.

LTE support mixed data, voice, video and messaging traffic and use OFDM (Orthogonal Frequency Division Multiplexing) and MIMO (Multiple Input Multiple Output) antenna technology similar to that used in the IEEE 802.11n wireless local area network (WLAN) standard. The higher signal to noise ratio (SNR) at the receiver enabled by MIMO, along with OFDM, provides improved coverage and throughput, especially in dense urban areas.

Core Network of 3G

noreply@blogger.com (Manpreet Singh Bindra) — Tue, 23 Nov 2010 17:32:00 +0000

The Core Network of 3G is divided in circuit switched and packet switched domains. Some of the circuit switched elements are Mobile services Switching Centre (MSC), Visitor location register (VLR) and Gateway MSC. Packet switched elements are Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN). Some network elements, like EIR, HLR, VLR and AUC are shared by both domains.

The Asynchronous Transfer Mode (ATM) is defined for UMTS core transmission. ATM Adaptation Layer type 2 (AAL2) handles circuit switched connection and packet connection protocol AAL5 is designed for data delivery.

The architecture of the Core Network may change when new services and features are introduced. Number Portability DataBase (NPDB) will be used to enable user to change the network while keeping their old phone number. Gateway Location Register (GLR) may be used to optimise the subscriber handling between network boundaries. MSC, VLR and SGSN can merge to become a UMTS MSC.

Dr. Jasleen BDS

Basic & Simple Definition to 3G

noreply@blogger.com (Manpreet Singh Bindra) — Tue, 23 Nov 2010 17:24:00 +0000

For common man 3G means

1. Video Call And
2. Fast Speed to download data.

a. The transfer rate for 3G networks is between 128 and 144 kbps (kilobits per second) for devices that are moving fast and 384 kbps for slow ones(like for pedestrians).

b. For fixed wireless LAN, the speed goes beyond 2 Mbps.

c. The first thing you require is a device (e.g. a mobile phone) that is 3G compatible. This is where the name 3G phone comes from - a phone that has 3G functionality; nothing to do with the number of cameras or the memory it has. An example is the iPhone 3G.

At Last 3G provides

Several times higher data speed;
Enhanced audio and video streaming;
Video-conferencing support;
Web and WAP browsing at higher speeds;
IPTV (TV through the Internet) support.

Operators launching 3G by 2010 end :

1. Tata Teleservices Ltd.
2. Vodafone Essar Ltd.
3. Airtel

India's largest mobile service provider, Bharti Airtel has announced that it will Launch its 3G Services in 13 Circles across India by 2010 End. Airtel becoming the third private operator after Tata Teleservices Ltd. and Vodafone Essar Ltd. to announce 3G service plans in the world's fastest growing telecommunications market. In May 2010, Airtel succesfully won the bid for 13 telecom zones for INR122.95 billion ($2.77 billion).

Er. Manpreet Singh Bindra
India

Business Wireless Planning Strategy

noreply@blogger.com (Manpreet Singh Bindra) — Wed, 22 Sep 2010 08:00:00 +0000

Business Wireless Planning Strategy

Business Planning

New entrants to wireless have the daunting task of attracting marketshare in an increasingly competitive environment. Identifying the coverage footprint that will deliver the target ROI hinges on many variables, such as the underlying demographics, competitor footprint, technology capability and target service offering. Subscriber projections, churn, and average revenue per unit (ARPU) are tied closely to system performance and device capabilities. The Wireless Strategy team has built new markets from the ground up, and can turn the multivariate view of technical, marketing, and competitive data into a coherent financial and operational plan. We understand the business of wireless technology.

Spectrum Valuation

The value of spectrum depends on both business and technical factors. FCC regulations, interference concerns, and existing and future uses of the spectrum and adjacent blocks all affect its viability for various technologies. The technology's true performance will impact the services that can be offered, which will impact the revenue opportunity. Wireless Strategy understands both sides of the equation and can solve for the true value.

Strategic Analysis

The wireless sector offers unlimited investment opportunities. But which new wireless technologies will be adopted by operators, and which ones will be left by the wayside? Which new wireless entrants or traditional operators will be capable of growing to the next level of performance and deliver significant returns on investment? Wireless Strategy's partners have years of experience in analyzing new technologies and assessing their value to the wireless operator.

Technology Briefings

We have years of experience in briefing wireless executives on technical subjects, providing clear, concise summaries of the relevant information affecting their business. Investors benefit from our unbiased assessments of technologies and operator performance. Whether explaining the basics of wireless operations or identifying the impact of a new technology on a business, we are ready to brief executives and investors on the best path forward.

Executive Services

The wireless industry has seen numerous mergers and turbulence in recent years. Wireless Strategy can provide stability through management change by teaming with the business organizations and delivering continuity and focus on company performance. Our partners are well qualified to fill technology and operations executive positions on a temporary or longer term basis.

Karl

USA

Nokia Dual Sim Phones

noreply@blogger.com (Manpreet Singh Bindra) — Wed, 22 Sep 2010 07:56:00 +0000

Nokia Dual Sim Phones

The new dual SIM phones, Nokia C1 (C1-00) and Nokia C2 (C2-00), were affordable entry level phones which will give maximum battery back up. Company claimed that these models, especially Nokia C1, will provide a standby battery time of up to six weeks, the longest ever for a Nokia phone.

The Nokia C1 was a basic model without much multimedia features. The users can only use this type for voice and SMS. It has a FM radio, a flashlight and colour screen. The 'call divert' feature will help the users not to miss a call from either of the two SIMs.

The users can switch between the two SIM cards by simply holding down a key. Users can buy Nokia C1 at just Rs 1999.

Nokia C2 has features like Ovi Mail and Ovi Life Tools, which provides information on healthcare, agriculture, education and entertainment. The memory capacity can be expanded upto 32 GB using Micro SD cards. Users can buy this dual SIM phone at just Rs 2500.

Puneet Tripathi

4G Technology : 4th Generation Technology

noreply@blogger.com (Manpreet Singh Bindra) — Sat, 28 Aug 2010 11:51:00 +0000

The fourth generation of mobile networks will truly turn the current mobile phone networks, in to end to end IP based networks, couple this with the arrival of IPv6, every device in the world will have a unique IP address, which will allow full IP based communications from a mobile device, right to the core of the internet, and back out again. If 4G is implemented correctly, it will truly harmonise global roaming, super high speed connectivity, and transparent end user performance on every mobile communications device in the world.

4G is set to deliver 100mbps to a roaming mobile device globally, and up to 1gbps to a stationary device. With this in mind, it allows for video conferencing, streaming picture perfect video and much more.

It wont be just the phone networks that need to evolve, the increased traffic load on the internet as a whole (imagine having 1 billion 100mb nodes attached to a network over night) will need to expand, with faster backbones and oceanic links requiring major upgrade.

4G wont happen over night, it is estimated that it will be implemented by 2010, and if done correctly, should take off rather quickly.

WiMAX Introduction

noreply@blogger.com (Manpreet Singh Bindra) — Sat, 06 Feb 2010 19:53:00 +0000

WiMAX Introduction

WiMax (Worldwide Interoperability for Microwave Access) is a wireless broadband technology, which supports point to multi-point (PMP) broadband wireless access.

WiMax is basically a new shorthand term for IEEE Standard 802.16, which was designed to support the European standards. 802.16's predecessors (like 802.11a) were not very acc ommodative of the European standards, per se.

The IEEE wireless standard has a range of up to 30 miles, and can deliver broadband at around 75 megabits per second. This is theoretically, 20 times faster than a commercially available wireless broadband.

The 802.16, WiMax standard was published in March 2002 and provided updated information on the Metropolitan Area Network (MAN) technology. The extension given in the March publication, extended the line-of-sight fixed wireless MAN standard, focused solely on a spectrum from 10 GHz to 60+ GHz.

This extension provides for non-line of sight access in low frequency bands like 2 - 11 GHz. These bands are sometimes unlicensed. This also boosts the maximum distance from 31 to 50 miles and supports PMP (point to multipoint) and mesh technologies.

The IEEE approved the 802.16 standards in June 2004, and three working groups were formed to evaluate and rate the standards.

WiMax can be used for wireless networking like the popular WiFi. WiMax, a second-generation protocol, allows higher data rates over longer distances, efficient use of bandwidth, and avoids interference almost to a minimum. WiMax can be termed partially a successor to the Wi-Fi protocol, which is measured in feet, and works, over shorter distances.

Manpreet Singh Bindra

Hotmail: Free, trusted and rich email service. Get it now.

OPTICAL CHARACTERISTICS OF LEDS

noreply@blogger.com (Manpreet Singh Bindra) — Mon, 28 Sep 2009 19:04:00 +0000

The radiation from an LED can be characterized by radiometric and spectroradiometric
quantities. If the LED emits visible radiation, then photometric and colorimetric quantities
are also required to quantify its effect on the human eye. Note that for every radiometric
quantity there is a photometric analog. The only difference is that, for radiometric quantities
the radiation is evaluated in energy units, while for photometric quantities the radiation is
weighted against the photopic response of the human eye.

3.1 Spectral Properties of Light Emitting Diodes

The spectral distribution of the optical radiation emitted by LEDs distinguish them from
typical element sources. The radiant power is neither monochromatic (as emitted by lasers),
nor broadband (as found with incandescent lamps), but rather something between the two.
The light output of a typical LED has a narrowband spectral bandwidth between 20nm and
50nm and a peak wavelength somewhere in the near UV, the visible, or near infrared regions
of the spectrum.

Sample LED Spectral Distributions

The spectral properties of an LED are important to aid
manufacturers in their design efforts and process control.
End-users use these values in determining the correct LED
for their application. An overview of the spectral parameters
of an LED is listed below:
Peak Wavelength λp:
Wavelength at the maximum spectral power . The peak wavelength has little significance for
practical purposes since two LEDs may have the same peak
wavelength but different color perception.
Full Width Half Max (FWHM):
The spectral bandwidth at half peak λ 0.5 is calculated from
the two wavelengths λ'0.5 and λ''0.5 on either side of λp.
λ 0.5 = λ'0.5 - λ''0.5 (Reference Figure 3.0).
Center Wavelength λ m:
The center wavelength is the wavelength halfway between the half-wavelengths λ'0.5 - λ''0.5.
Centroid Wavelength λc:
The centroid wavelength is the center of moment or the mean of the spectral power
distribution.
Dominant Wavelength:
The dominant wavelength is determined from drawing a straight line through the color
coordinates of the reference illuminant (usually arbitrarily chosen as illuminant E) and
the measured chromaticity coordinates of the LED in the International Commission on
Illumination (CIE) 1931 chromaticity diagram. The intersection of this straight line on
the boundary of the chromaticity diagram gives the dominant wavelength. It is a measure
of the hue sensation produced in the human eye by the LED.
Purity:
Purity is defined as the ratio of the distance from reference illuminant (usually arbitrarily
chosen as Illuminant E) to the measured chromaticity coordinates and the distance from
reference illuminant to the intersection with the boundary of the chromaticity diagram.
Most LEDs are narrow band radiators, with a purity of nearly 100%, i.e. the color cannot
be distinguished from a monochromatic beam. Polychromatic sources have low purity
approaching zero.
Full Width Half Max Angle , Viewing Angle or Beam Angle:
The total cone apex angle in degrees encompassing the central, high luminous intensity
portion of a directional beam, from the on-axis peak out to the off-axis angles in both
directions at which the source's relative intensity is 1/2.
Half-Angle:
The included angle in degrees between the peak and the point on one side of the beam
axis at which the luminous intensity is 50% of maximum or half of the beam angle.
Note: Peak Wavelength, Full Width Half Max, Center Wavelength, and Centroid
Wavelength are all plotted on a scale of (power / λ) vs. (λ).
0.5
(2θ1/2)
4

Theoretical V(λ) function, relative
spectral flux output of a blue LED,
relative spectral distribution of a
typical tungsten incandescent lamp,
typical response of photopic detector
with f1’ response of 4%.
3.2 Comparison of Photometers and Spectroradiometers
Photometers use a broadband detector in conjunction with an optical filter in an effort to
simulate the spectral luminous efficiency curve of the human eye, V(λ), which is referenced
using CIE 15.2 Colorimetry. The detection process involves a change in the
characteristics of the detector caused by the absorption of visible photons. The electrical
signal generated by the detector is a response to the visible radiation incident on the detector
active area. For example, a photometer designed to measure illuminance may be calibrated
in photocurrent per lux.
Spectroradiometers can be calibrated to measure the radiant energy or radiant flux from an
LED as a function of wavelength. These instruments separate or disperse polychromatic light
into its constituent monochromatic components usually by means of prisms or gratings. The
photometric value may then be computed (usually by software) from this measured spectrum.
This basic difference between spectroradiometers and photometers is extremely important in
LED metrology.
A disadvantage of a photometer is the difficulty in designing a filter that, when combined
with a detector, fits the spectral luminous efficiency curve of the eye exactly. Because of
available filter materials, a mismatch is particularly prevalent in the blue portion of the
spectrum. Though corrections can be applied, these corrections require knowledge of the
LED spectral distribution and are usually approximations. Figure 3.1 shows the theoretical
V(λ) function, the relative spectral flux output of a blue LED, the relative spectral distribution
of a typical tungsten incandescent lamp, and the typical response of a photopic detector.
A typical photopic detector with an f1' response of 4% can have a spectral mismatch as great
as a factor of 2 at 470nm between the V(λ) function and the response of a photopic detector.
If an incandescent source or a source similar in spectral content is measured, the correction
for the slopes of the photopic detector to the V(λ) curve is minimal since the light is
continuous and there is relatively little light in the
blue portion of the spectrum in relation to the
higher wavelengths. A mismatch in the response
curves results in only a slight error of the measured
photometric value.
LEDs, however, have a completely different spectral
power distribution, which tends to be narrowband
Gaussian with a specific peak and a FWHM of a
couple of tens of nanometers. The relatively poor
match of the photopic detector to the V(λ) function,
can result in large deviations in the measured photometric
quantities. This is particularly true for blue
and red LEDs. Errors exceeding a hundred percent
are not unusual for blue LEDs. Spectroradiometers
avoid these errors because the photometric quantities
are calculated from the spectral data and defined CIE
functions. It should be noted that photometers can
be used to compare sources having identical spectral
distribution, or to measure illumination of the same spectral distribution as that of the source
with which it was calibrated. LEDs can have so much variation from one to another, spectroradiometers
or photometers fabricated with specially designed filtering should be used for
LED metrology.
5
3.3 Color and Dominant Wavelength
Often used for determining the color of an LED, dominant wavelength is actually a
measure of the hue sensation produced in the human eye. Hue designates the basic color
being referenced; such as, red, yellow or blue-green. The hue refers to the color impression
that a sample makes. Two LEDs can have the same hue, but it is possible for one to appear
washed out. For example, one can look red and one can look pink.
In order to guarantee a match in color from one LED to another both dominant wavelength
and purity should be referenced. Purity is a characteristic of chroma (also referred to as
saturation), which is the degree of color saturation, or the amount of pure color added to
obtain the sample. The purer colors of a particular hue sample are placed nearer to the
boundary of the chromaticity diagram.
In order to calculate the color properties of an LED, the spectral properties of the LED
must be known. Therefore, a photometer cannot be used. In choosing a spectroradiometer
with which to calculate these values, it should be noted that the optical bandwidth of a
spectroradiometer artificially broadens the spectral shape of any source. For LEDs, this
can introduce errors, especially in the calculated chromaticity coordinates and dominant
wavelength. A 10nm bandwidth spectroradiometer, measuring 20nm full width half max
LEDs, can cause errors as high as:
0.005 in x
0.007 in y
2nm in λd
On the other hand, error contributions on color for spectroradiometers with bandwidths
of 5nm have been documented to be less than about 0.002 in x,y (0.001 in u',v') and 0.2nm
in dominant wavelength. Bandwidths of 1nm or less have no appreciable error contribution.
In choosing a spectroradiometer one should be aware of these errors. Spectroradiometers
with bandwidths of 5nm or less are accepted for most practical measurements of LEDs
of all colors.
3.4 Influence of Temperature on Radiation
Initial Light-up:
The light output of an LED is a function of Vf and If,
where the LED junction temperature under constant current
operation heavily influences Vf. At constant current.
the forward voltage of an LED stabilizes as the junction
temperature (Tj) stabilizes. The junction temperature of
the LED is determined by Tj =Ta + Pd * Rth (j-a). Where
Ta is ambient temperature, Pd is power dissipation (Vf *I f)
and Rth(j-a) is the thermal resistance (junction to ambient
temperature). During initial light-up, the temperature of
the junction increases due to electrical power consumed
by the LED chip and then stabilizes at a temperature
value > Ta. Because of this effect, the emitted light is not
stabilized until thermal equilibrium has been reached.
After thermal equilibrium, the junction value is governed
by the heat transfer to the surroundings, which takes
place through the leads of the LED. As a consequence,
the thermal properties of the electrical contacts used to
supply the LED, the length of the wires between the chip, and when used the heat sink can
significantly affect the output. Figure 3.2 shows the stabilization over time of a green LED.
The relative spectral flux and the forward voltage is measured every 5 seconds with a constant
current of 20ma flowing through the LED, until a near constant forward voltage is achieved. The stabilization procedure can take several minutes and will be
influenced by the properties of the specific LED measured. Depending on the LED type,
spectral distribution effects from junction temperature, as presented in the graph, can create
6 shifts in dominant wavelength

Example of LED
Stabilization Over Time
as great as 0.7nm and decreases in luminous flux as great as
3.5%. Since the dominant wavelength is dependent upon
the intersection on the spectrum locus of the 1931 CIE
chromaticity diagram, small spectral distribution changes
in "red" and "blue" LEDs can create relatively large changes
in dominant wavelength.
Thermal Equilibrium:
Once thermal equilibrium has been reached, the spectral
distribution of an LED is dependent upon the ambient
temperature surrounding the chip. For a typical LED as the
power is stabilized and the ambient temperature rises, there
will be a slight change in the shape of the spectrum, and the
peak wavelength will shift about 0.1 to 0.3nm/K. For blue
LEDs, the shift in most cases is towards shorter wavelengths.
For other LEDs, the whole distribution will shift in the
direction of longer wavelengths. The luminous efficacy and color of LEDs can be changed by
relatively small ambient temperature changes, making it difficult to achieve constant photometric
or radiometric measurement results. Figure 3.3 depicts the spectral radiant flux output
of a "green" LED run at 23°C and 30°C. For this example, a 1.1nm shift in peak wavelength
resulted in a 0.2nm change in dominant wavelength. As previously described, shifts in the
spectra of red and blue LEDs, because of their location on the color curve, will create greater
changes in dominant wavelength. Since the spectral distribution of an LED depends on both
the junction temperature of the chip and stabilization of current, temperature offers the best
way of controlling the operating conditions and maintaining a constant spectral distribution.

STRUCTURED CABLES IN TELECOMMUNICATION

noreply@blogger.com (Manpreet Singh Bindra) — Mon, 28 Sep 2009 18:53:00 +0000

Cable is the highway used to deliver all of you organization's information. A system that is poorly designed, ineffectively installed, or out of date hinders the performance, profitability and client satisfaction in your organization

TNSI has the experience and capability to tie your cabling needs together for maximum efficiency in a cost effective manner, in your building or in a campus environment.

Voice: Structured wiring for voice, modem, terminal, fax and other applications.

Data: Structured wiring systems for local area networks, host terminal, data collection, factory automation. Category 5 and 6 copper twisted pair, patch panels, ladder and system racks, network services access, building connection, and many other applications.

Fiber Optics: Backbone and workstation cable systems using single or mutimode fiber. We offer a variety of fiber optic systems for unique applications.

High Speed Internet Access: Access the information Super Highway using a high speed internet connection.

AIRTEL Success Story

noreply@blogger.com (Manpreet Singh Bindra) — Fri, 12 Jun 2009 18:29:00 +0000

Airtel’s solutions provider, Bharti Telesoft, designed a unique televoting application that uses Short Messages as the media for polling votes. The application was developed on open standards. Televoting effectively enables Airtel’s mobile subscribers to participate in various SMS contests aired on both KBC & Indian Idol. The system handles tremendous peak loads of mobile-originated (MO) messages generated by subscribers and processes it according to a pre-configured format specified by the two TV programs. The application caters to subscriber traffic across millions of users in seven different Airtel Circles over a pre-defined short code (646).

“When we first decided to evaluate Linux, apprehensions were raised immediately. People began to say that the system would choke and not be able to handle the load,” explains Vatsal.

“But in our simulations, Linux proved its detractors completely wrong. The pilot Enterprise Linux server could handle a peak load of 1000 TPS with superb ease. People soon began to realize that Linux is in fact ideally suited for high throughputs. Since our transactions needed to be recorded into a log file on-the-fly, Linux, with its high performance, was the perfect fit,” he adds.

Security was also another critical factor that swung the decision in the favor of Enterprise Linux. “Microsoft Windows is prone to viruses that affect its filesystem easily, whereas Linux remains unaffected,” he adds. In fact, Windows was never on the selection radar at all. “We didn’t even evaluate it for our server requirements,” adds Vatsal.

At Airtel, Enterprise Linux runs on low cost, dual Intel Xeon servers. The servers run both the Televoting application and a MySQL database at each of the seven different locations across the country. A central server, again powered by Red Hat Enterprise Linux, functions as a host. “The central server generates MIS reports and also acts as an FTP server for the other seven distributed machines,” explains Uttam Kumar, Project Head, Airtel.

Wireless Code Division Multiple Access (CDMA)

noreply@blogger.com (Manpreet Singh Bindra) — Fri, 12 Jun 2009 18:26:00 +0000

Code Division Multiple Access (CDMA) is a radically new concept in wireless communications. It has gained widespread international acceptance by cellular radio system operators as an upgrade that will dramatically increase both their system capacity and the service quality. It has likewise been chosen for deployment by the majority of the winners of the United States Personal Communications System spectrum auctions. It may seem, however, mysterious for those who aren't familiar with it. This site is provided in an effort to dispel some of the mystery and to disseminate at least a basic level of knowledge about the technology.

CDMA is a form of spread-spectrum , a family of digital communication techniques that have been used in military applications for many years. The core principle of spread spectrum is the use of noise-like carrier waves, and, as the name implies, bandwidths much wider than that required for simple point-to-point communication at the same data rate. Originally there were two motivations: either to resist enemy efforts to jam the communications (anti-jam, or AJ), or to hide the fact that communication was even taking place, sometimes called low probability of intercept (LPI). It has a history that goes back to the early days of World War II.

The use of CDMA for civilian mobile radio applications is novel. It was proposed theoretically in the late 1940's, but the practical application in the civilian marketplace did not take place until 40 years later. Commercial applications became possible because of two evolutionary developments. One was the availability of very low cost, high density digital integrated circuits, which reduce the size, weight, and cost of the subscriber stations to an acceptably low level. The other was the realization that optimal multiple access communication requires that all user stations regulate their transmitter powers to the lowest that will achieve adequate signal quality.

CDMA changes the nature of the subscriber station from a predominately analog device to a predominately digital device. Old-fashioned radio receivers separate stations or channels by filtering in the frequency domain. CDMA receivers do not eliminate analog processing entirely, but they separate communication channels by means of a pseudo-random modulation that is applied and removed in the digital domain, not on the basis of frequency. Multiple users occupy the same frequency band. This universal frequency reuse is not fortuitous. On the contrary, it is crucial to the very high spectral efficiency that is the hallmark of CDMA. Other discussions in these pages show why this is true.

CDMA is altering the face of cellular and PCS communication by:

Dramatically improving the telephone traffic capacity
Dramatically improving the voice quality and eliminating the audible effects of multipath fading
Reducing the incidence of dropped calls due to handoff failures
Providing reliable transport mechanism for data communications, such as facsimile and internet traffic
Reducing the number of sites needed to support any given amount of traffic
Simplifying site selection
Reducing deployment and operating costs because fewer cell sites are needed
Reducing average transmitted power
Reducing interference to other electronic devices
Reducing potential health risks

Commercially introduced in 1995, CDMA quickly became one of the world's fastest-growing wireless technologies. In 1999, the International Telecommunications Union selected CDMA as the industry standard for new "third-generation" (3G) wireless systems. Many leading wireless carriers are now building or upgrading to 3G CDMA networks in order to provide more capacity for voice traffic, along with high-speed data capabilities.

CDMA is a form of Direct Sequence Spread Spectrum communications. In general, Spread Spectrum communications is distinguished by three key elements:

1. The signal occupies a bandwidth much greater than that which is necessary to send the information. This results in many benefits, such as immunity to interference and jamming and multi-user access, which we'll discuss later on.

2. The bandwidth is spread by means of a code which is independent of the data. The independence of the code distinguishes this from standard modulation schemes in which the data modulation will always spread the spectrum somewhat.

3. The receiver synchronizes to the code to recover the data. The use of an independent code and synchronous reception allows multiple users to access the same frequency band at the same time.

In order to protect the signal, the code used is pseudo-random. It appears random, but is actually deterministic, so that the receiver can reconstruct the code for synchronous detection. This pseudo-random code is also called pseudo-noise (PN).

There are three ways to spread the bandwidth of the signal:

Frequency hopping. The signal is rapidly switched between different frequencies within the hopping bandwidth pseudo-randomly, and the receiver knows before hand where to find the signal at any given time.
Time hopping. The signal is transmitted in short bursts pseudo-randomly, and the receiver knows beforehand when to expect the burst.
Direct sequence. The digital data is directly coded at a much higher frequency. The code is generated pseudo-randomly, the receiver knows how to generate the same code, and correlates the received signal with that code to extract the data.

How spread spectrum works:

Spread Spectrum uses wide band, noise-like signals. Because Spread Spectrum signals are noise-like, they are hard to detect. Spread Spectrum signals are also hard to Intercept or demodulate. Further, Spread Spectrum signals are harder to jam (interfere with) than narrowband signals. These Low Probability of Intercept (LPI) and anti-jam (AJ) features are why the military has used Spread Spectrum for so many years. Spread signals are intentionally made to be much wider band than the information they are carrying to make them more noise-like.

Spread Spectrum signals use fast codes that run many times the information bandwidth or data rate. These special "Spreading" codes are called "Pseudo Random" or "Pseudo Noise" codes. They are called "Pseudo" because they are not real gaussian noise.

Spread Spectrum transmitters use similar transmit power levels to narrow band transmitters. Because Spread Spectrum signals are so wide, they transmit at a much lower spectral power density, measured in Watts per Hertz, than narrowband transmitters. This lower transmitted power density characteristic gives spread signals a big plus. Spread and narrow band signals can occupy the same band, with little or no interference. This capability is the main reason for all the interest in Spread Spectrum today.

BSNL DATAONE broadband disconnect problem

noreply@blogger.com (Manpreet Singh Bindra) — Wed, 13 May 2009 14:57:00 +0000

Hello
folks....Internet now spreading its roots deep n further deep inside
the Indian households.BSNL has come up with Broadband service Dataone
with really awesome price plans 500 bucks for 1 GB thing....sounds
koool...no???
But many of us are facing problems with Dataone
service that the Green Light of DSL in broadband modem switches off
time to time rendering you off the net for long time afterwards.
So im giving you a solution here which is a by-mistake discovery by in-house research team:-) and its 100% working:
When ever your DSL light goes off...
pick
up the phone co-attached to your modem and dial any number and the DSL
light will switch ON[blinking]...that moment only you drop back the
phone reciever.And reconnect the Broadband connection.Simple!!!
NOTE: DSL light may not switch on in one Dial attempt only..so try 2-3 times and it will work...

Setting Priorities for Next-Generation Web Apps - MICROSOFT

noreply@blogger.com (Manpreet Singh Bindra) — Sun, 19 Apr 2009 15:20:00 +0000

Through the use of new development environments, combined with Web services and an emerging set of collaboration technologies, Web applications are matching and threatening to exceed the capabilities of their shrink-wrapped antecedents. It's safe to say that the days of classical offline desktop applications and simple informational Web sites are rapidly drawing to a close. It's also safe to say that while the next generation of Web applications will combine both the richness of the desktop and the networking of the Internet, there are still a number of concerns that need to be addressed around security, transition costs, and other factors.

For this report, InformationWeek Analytics polled both technical decision makers (TDMs) and business decision makers (BDMs) for their interest in, and concerns about, next-generation Web applications in three areas: advancements in user interface; the integration of business intelligence and event processing with collaboration tools; and their interest in hosting some application functions in the cloud. One result of the survey that shouldn't surprise anyone is the popularity of "eye candy" rich Internet applications (RIAs) with both TDMs and BDMs.The consensus of our survey of 415 business technology professionals indicates that RIAs are widely accepted and are now the technology of choice for many new Web development projects.

Although not as far along as most corporate RIA initiatives, there is similar interest in the use of combined business intelligence, event processing, and collaboration tools to kick off complex tasks, such as bringing appropriate teams together to make critical decisions and alerting stake holders of key developments.While there is some interest among smaller companies and startups for hosting applications in the cloud—as a way to add robust IT infrastructure at minimal cost, for example—enterprise decision makers by and large are much more skeptical about cloud computing, citing issues such as security, governance, privacy, and control.That skepticism is reflected in the 50% negative response from both TDMs and BDMs who said they do not expect to host any application functions in the cloud over the next 24 months.

This point was made more vociferously by Scott Wentzka, a senior architect with Paisley Consulting, a Minnesota provider of governance, risk, and compliance software. "Cloud computing is an over-priced fraud," says Wentzka. "If you actually figure out the real TCO, it's about four times as expensive as internally hosted applications. On the other hand, RIA technology is the real deal—faster, more interactive, and less painful to develop than the ancient kludge that is HTML and JavaScript."

Social Network Services

noreply@blogger.com (Manpreet Singh Bindra) — Mon, 13 Apr 2009 15:02:00 +0000

Social network services allow people to come together online around shared interests, hobbies, or causes. For example, some sites provide dating services where users post personal profiles, locations, ages, gender, etc, and are able to search for a partner. Other services enable business networking (Ryze, XING, and LinkedIn) and social event meetups (Meetup).

Some large wikis effectively become social network services by encouraging user pages and portals.

Anyone can create their own social networking service using hosted offerings like Ning or rSitez, or more flexible, installable software like Elgg.

Social network search engines::

Social network search engines are a class of search engines that use social networks to organize, prioritize, or filter search results. There are two subclasses of social network search engines: those that use explicit social networks, and those that use implicit social networks:
Explicit social network search engines allow people to find each other according to explicitly stated social relationships such as XFN social relationships. XHTML Friends Network, for example, allows people to share their relationships on their own sites, thus forming a decentralized/distributed online social network, in contrast to centralized social network services listed in the previous section.
Implicit social network search engines allow people to filter search results based upon classes of social networks they trust, such as a shared political viewpoint. This was called an epistemic filter in a United Nations University report from 1993 which predicted that this would become the dominant means of search for most users.

Lacking trustworthy explicit information about such viewpoints, this type of social network search engine mines the web to infer the topology of online social networks. For example, the NewsTrove search engine infers social networks from content - sites, blogs, pods, and feeds - by examining, among other things, subject matter, link relationships, and grammatical features to infer social networks.

Deliberative social networks

Deliberative social networks are webs of discussion and debate for decision-making purposes. They are built for the purpose of establishing sustained relationships between individuals and their government. They rely upon informed opinion and advice that is given with a clear expectation of outcomes.

Commercial social networks

Commercial social networks are designed to support business transaction and to build a trust between an individual and a brand, which relies on opinion of product, ideas to make the product better, enabling customers to participate with the brands in promoting development, service delivery, and a better customer experience.[citation needed]. an example of these networks is Dell IdeaStorm.

Social guides

A social guide recommending places to visit or contains information about places in the real world such as coffee shops, restaurants, and wifi hotspots, etc. One such application is WikiTravel.

Social bookmarking
Main article: Social bookmarking

Some Web sites allow users to post their list of bookmarks or favorites websites for others to search and view them. These sites can also be used to meet others sharing common interests. Examples include digg, del.icio.us, StumbleUpon, reddit, Netvouz, and furl.

Social cataloging

In Social cataloging much like social bookmarking, this software is aimed towards academics, and allows the user to post a citation for an article found on the internet or a website, online database like Academic Search Premier or LexisNexis Academic University, a book found in a library catalog, and so on. These citations can be organized into predefined categories or a new category defined by the user through the use of tags. This allows academics researching or interested in similar areas to connect and share resources. Examples for those services include CiteULike, Connotea, BibSonomy and refbase.

Social libraries

This applications allows visitors to keep track of their collectibles, books, records, and DVDs. Users can share their collections. Recommendations can be generated based on user ratings, using statistical computation and network theory. Some sites offer a buddy system, as well as virtual "check outs" of items for borrowing among friends. Folksonomy or tagging is implemented on most of these sites. Examples include discogs.com, imdb.com and LibraryThing.

Virtual worlds
Main article: Virtual world

Virtual Worlds are services where it is possible to meet and interact with other people in a virtual environment reminiscent of the real world. Thus the term virtual reality. Typically, the user manipulates an avatar through the world, interacting with others using chat or voice chat.

Massively Multiplayer Online Games (MMOGs)
Main article: Massively Multiplayer Online Games

MMOGs are virtual worlds that add various sorts of point systems, levels, competition, and winners and losers to virtual world simulation. Commercial MMOGs (or, more accurately, massively multiplayer online role-playing games or MMORPGs,) include Everquest and World of Warcraft. The Dotsoul Cyberpark is one of the more innovative non-commercial worlds, with the look and feel of Second Life and Active Worlds, but an adamantly anti-corporate stance. Other open-source and experimental examples include Planeshift, Croquet project, VOS and Solipsis.

Non-game worlds

Another development are the worlds that are less game-like, or not games at all. Games have points, winners, and losers. Instead, some virtual worlds are more like social networking services like MySpace and Facebook, but with 3D simulation features. Examples include Second Life, ActiveWorlds, The Sims Online, and There.

Economies

Very often a real economy emerges in these worlds, extending the non-physical service economy within the world to service providers in the real world. Experts can design dresses or hairstyles for characters, go on routine missions for them, and so on, and be paid in game money to do so. This emergence has resulted in expanding social possibility and also in increased incentives to cheat. In the case of Second Life, the in-world economy is one of the primary features of the world.

Other specialized social applications

There are many other applications with social software characteristics that facilitate human connection and collaboration in specific contexts. Project management and e-learning applications are among these.

Emerging technologies

Emerging technological capabilities to more widely distribute hosting and support much higher bandwidth in real time are bypassing central content arbiters in some cases.

Peer-to-peer social networks

A hybrid of web-based social networks, instant messaging technologies and peer-to-peer connectivity and file sharing, peer-to-peer social networks generally allow users to share blogs, files (especially photographs) and instant messages. Some examples are imeem, SpinXpress, Bouillon, Wirehog, and Soulseek. Also, Groove, WiredReach and Kerika have similar functionality, but with more of a work-based, collaboration bias.

Virtual presence

Widely viewed, virtual presence means being present via intermediate technologies, usually radio, telephone, television, or the internet. In addition, it can denote apparent physical appearance, such as voice, face, and body language.

More narrowly, the term virtual presence denotes presence on World Wide Web locations which identified by URLs. People who are browsing a web site are considered to be virtually present at web locations. Virtual presence is a social software in the sense that people meet on the web by chance or intentionally. The ubiquitous(in the web space) communication transfers behavior patterns from the real world and virtual worlds to the web. Research has demonstrated effects of online indicators

CCTV IP camera

noreply@blogger.com (Manpreet Singh Bindra) — Mon, 13 Apr 2009 15:00:00 +0000

IP cameras are Closed-circuit television (CCTV) cameras that utilize Internet Protocol to transmit image data and control signals over an Fast Ethernet link. As such, IP cameras are also commonly referred to as network cameras. IP cameras are primarily used for surveillance in the same manner as analog closed-circuit_television. A number of IP cameras are normally deployed together with a digital video recorder (DVR) or a network video recorder (NVR) to form a video surveillance system.

The terms IP camera and network camera are most commonly used to refer to surveillance cameras with a Fast Ethernet interface. In this context, the term IP camera does not include GigE_Vision camera, which is a machine vision camera with a Gigabit Ethernet interface.

Is Your Networking Caught A Virus?

noreply@blogger.com (Manpreet Singh Bindra) — Mon, 13 Apr 2009 14:58:00 +0000

Caught A Virus?

If you've let your guard down--or even if you haven't--it can be hard to tell if your PC is infected. Here's what to do if you suspect the worst.

Heard this one before? You must run antivirus software and keep it up to date or else your PC will get infected, you'll lose all your data, and you'll incur the wrath of every e-mail buddy you unknowingly infect because of your carelessness.

You know they're right. Yet for one reason or another, you're not running antivirus software, or you are but it's not up to date. Maybe you turned off your virus scanner because it conflicted with another program. Maybe you got tired of upgrading after you bought Norton Antivirus 2001, 2002, and 2003. Or maybe your annual subscription of virus definitions recently expired, and you've put off renewing.

It happens. It's nothing to be ashamed of. But chances are, either you're infected right now, as we speak, or you will be very soon.

For a few days in late January, the Netsky.p worm was infecting about 2,500 PCs a day. Meanwhile the MySQL bot infected approximately 100 systems a minute (albeit not necessarily desktop PCs). As David Perry, global director of education for security software provider Trend Micro, puts it, "an unprotected [Windows] computer will become owned by a bot within 14 minutes."

Today's viruses, worms, and so-called bots--which turn your PC into a zombie that does the hacker's bidding (such as mass-mailing spam)--aren't going to announce their presence. Real viruses aren't like the ones in Hollywood movies that melt down whole networks in seconds and destroy alien spacecraft. They operate in the background, quietly altering data, stealing private operations, or using your PC for their own illegal ends. This makes them hard to spot if you're not well protected.

Is Your PC "Owned?"

I should start by saying that not every system oddity is due to a virus, worm, or bot. Is your system slowing down? Is your hard drive filling up rapidly? Are programs crashing without warning? These symptoms are more likely caused by Windows, or badly written legitimate programs, rather than malware. After all, people who write malware want to hide their program's presence. People who write commercial software put icons all over your desktop. Who's going to work harder to go unnoticed?

Other indicators that may, in fact, indicate that there's nothing that you need to worry about, include:

* An automated e-mail telling you that you're sending out infected mail. E-mail viruses and worms typically come from faked addresses.
* A frantic note from a friend saying they've been infected, and therefore so have you. This is likely a hoax. It's especially suspicious if the note tells you the virus can't be detected but you can get rid of it by deleting one simple file. Don't be fooled--and don't delete that file.

I'm not saying that you should ignore such warnings. Copy the subject line or a snippet from the body of the e-mail and plug it into your favorite search engine to see if other people have received the same note. A security site may have already pegged it as a hoax.

Sniffing Out an Infection

There are signs that indicate that your PC is actually infected. A lot of network activity coming from your system (when you're not actually using Internet) can be a good indicator that something is amiss. A good software firewall, such as ZoneAlarm, will ask your permission before letting anything leave your PC, and will give you enough information to help you judge if the outgoing data is legitimate. By the way, the firewall that comes with Windows, even the improved version in XP Service Pack 2, lacks this capability.

To put a network status light in your system tray, follow these steps: In Windows XP, choose Start, Control Panel, Network Connections, right-click the network connection you want to monitor, choose Properties, check "Show icon in notification area when connected," and click OK.

If you're interested in being a PC detective, you can sniff around further for malware. By hitting Ctrl-Alt-Delete in Windows, you'll bring up the Task Manager, which will show you the various processes your system is running. Most, if not all, are legit, but if you see a file name that looks suspicious, type it into a search engine and find out what it is.

Want another place to look? In Windows XP, click Start, Run, type "services.msc" in the box, and press Enter. You'll see detailed descriptions of the services Windows is running. Something look weird? Check with your search engine.

Finally, you can do more detective work by selecting Start, Run, and typing "msconfig" in the box. With this tool you not only see the services running, but also the programs that your system is launching at startup. Again, check for anything weird.

If any of these tools won't run--or if your security software won't run--that in itself is a good sign your computer is infected. Some viruses intentionally disable such programs as a way to protect themselves.

What to Do Next

Once you're fairly sure your system is infected, don't panic. There are steps you can take to assess the damage, depending on your current level of protection.

* If you don't have any antivirus software on your system (shame on you), or if the software has stopped working, stay online and go for a free scan at one of several Web sites. There's McAfee FreeScan, Symantec Security Check, and Trend Micro's HouseCall. If one doesn't find anything, try two. In fact, running a free online virus scan is a good way to double-check the work of your own local antivirus program. When you're done, buy or download a real antivirus program.
* If you have antivirus software, but it isn't active, get offline, unplug wires-- whatever it takes to stop your computer from communicating via the Internet. Then, promptly perform a scan with the installed software.
* If nothing seems to be working, do more research on the Web. There are several online virus libraries where you can find out about known viruses. These sites often provide instructions for removing viruses--if manual removal is possible--or a free removal tool if it isn't. Check out GriSOFT's Virus Encyclopedia, Eset's Virus Descriptions, McAffee's Virus Glossary, Symantec's Virus Encyclopedia, or Trend Micro's Virus Encyclopedia.

A Microgram of Prevention

Assuming your system is now clean, you need to make sure it stays that way. Preventing a breach of your computer's security is far more effective than cleaning up the mess afterwards. Start with a good security program, such Trend Micro's PC-Cillin, which you can buy for $50.

Don't want to shell out any money? You can cobble together security through free downloads, such as AVG Anti-Virus Free Edition, ZoneAlarm (a personal firewall), and Ad-Aware SE (an antispyware tool).

Just make sure you keep all security software up to date. The bad guys constantly try out new ways to fool security programs. Any security tool without regular, easy (if not automatic) updates isn't worth your money or your time.

Speaking of updating, the same goes for Windows. Use Windows Update (it's right there on your Start Menu) to make sure you're getting all of the high priority updates. If you run Windows XP, make sure to get the Service Pack 2 update. To find out if you already have it, right-click My Computer, and select Properties. Under the General tab, under System, it should say "Service Pack 2."

Here are a few more pointers for a virus-free life:

* Be careful with e-mail. Set your e-mail software security settings to high. Don't open messages with generic-sounding subjects that don't apply specifically to you from people you don't know. Don't open an attachment unless you're expecting it.
* If you have broadband Internet access, such as DSL or cable, get a router, even if you only have one PC. A router adds an extra layer of protection because your PC is not connecting directly with the Internet.
* Check your Internet ports. These doorways between your computer and the Internet can be open, in which case your PC is very vulnerable; closed, but still somewhat vulnerable; or stealthed (or hidden), which is safest. Visit Gibson Research's Web site and run the free ShieldsUP test to see your ports' status. If some ports show up as closed--or worse yet, open--check your router's documentation to find out how to hide them.

Apple 3G iPhone Improving Networking

noreply@blogger.com (Manpreet Singh Bindra) — Mon, 13 Apr 2009 14:53:00 +0000

General

2G Network GSM 850 / 900 / 1800 / 1900
3G Network HSDPA 850 / 1900 / 2100
Announced 2008, June
Status Available. Released 2008, July

Size

Dimensions 115.5 x 62.1 x 12.3 mm
Weight 133 g
Display Type Capacitive touchscreen, 16M colors
Size 320 x 480 pixels, 3.5 inches
- Multi-touch input method
- Accelerometer sensor for auto-rotate
- Proximity sensor for auto turn-off
- Scratch-resistant surface
- Ambient light sensor

Ringtones

Type Polyphonic, MP3
Customization Download
Vibration Yes
- 3.5 mm headset jack

Memory

Phonebook Practically unlimited entries and fields, Photocall
Call records 100 received, dialed and missed calls
Internal 8 GB/ 16 GB
Card slot No

Data

GPRS Yes
HSCSD No
EDGE Yes
3G HSDPA
WLAN Wi-Fi 802.11b/g
Bluetooth Yes, v2.0, headset support only
Infrared port No
USB Yes, v2.0

Camera

Primary 2 MP, 1600x1200 pixels
Video No
Secondary No

Features

OS Mac OS X v10.4.10
Messaging SMS (threaded view), Email
Browser HTML (Safari)
Radio No
Games Downloadable
Colors Black(8/16 GB), White (16 GB)
GPS Yes, with A-GPS support
Java No
- Google Maps
- Audio/video player
- TV-out
- Photo browser
- Voice memo
- Integrated handsfree

Battery Standard battery, Li-Ion

Stand-by Up to 300 h

Talk time Up to 10 h

Analysis (Insertion and deletion operation)

noreply@blogger.com (Manpreet Singh Bindra) — Mon, 13 Apr 2009 14:52:00 +0000

The best possible case in insertion operation is when the item is inserted at the last position. In this case, no movement of elements is required. The worst case occurs when the element has to be inserted at the beginning of the list. In this case, we have to move all the elements down the list. Therefore, the while loop executes n times, each moving one element down. Thus complexity of insertin operation is O(n), i.e linear time.

.The best case in deletion occurs when the element to be deleted is the last element of the array. In this case, no element is moved up. The worst case occurs when element is deleted from the first position. In this case, all (n-1) elements are moved up. The while loop executes n-1 times, each time moving one element down. Thus complexity of deletion operation is also O(n) i.e linear time.

Spyware affecting Networking

noreply@blogger.com (Manpreet Singh Bindra) — Mon, 13 Apr 2009 14:48:00 +0000

There are a lot of PC users that know little about "Spyware", "Mal-ware", "hijackers", "Dialers" & many more. This will help you avoid pop-ups, spammers and all those baddies.

What is spy-ware?
Spy-ware is Internet jargon for Advertising Supported software (Ad-ware). It is a way for shareware authors to make money from a product, other than by selling it to the users. There are several large media companies that offer them to place banner ads in their products in exchange for a portion of the revenue from banner sales. This way, you don't have to pay for the software and the developers are still getting paid. If you find the banners annoying, there is usually an option to remove them, by paying the regular licensing fee.

Known spywares
There are thousands out there, new ones are added to the list everyday. But here are a few:
Alexa, Aureate/Radiate, BargainBuddy, ClickTillUWin, Conducent Timesink, Cydoor, Comet Cursor, eZula/KaZaa Toptext, Flashpoint/Flashtrack, Flyswat, Gator, GoHip, Hotbar, ISTbar, Lions Pride Enterprises/Blazing Logic/Trek Blue, Lop (C2Media), Mattel Brodcast, Morpheus, NewDotNet, Realplayer, Songspy, Xupiter, Web3000, WebHancer, Windows Messenger Service.

How to check if a program has spyware?
The is this Little site that keeps a database of programs that are known to install spyware.

Check Here: http://www.spywareguide.com/product_search.php

If you would like to block pop-ups (IE Pop-ups).
There tons of different types out there, but these are the 2 best, i think.

Try: Google Toolbar (http://toolbar.google.com/) This program is Free
Try: AdMuncher (http://www.admuncher.com) This program is Shareware

If you want to remove the "spyware" try these.
Try: Lavasoft Ad-Aware (http://www.lavasoftusa.com/) This program is Free
Info: Ad-aware is a multi spyware removal utility, that scans your memory, registry and hard drives for known spyware components and lets you remove them. The included backup-manager lets you reinstall a backup, offers and multi language support.

Try: Spybot-S&D (http://www.safer-networking.org/) This program is Free
Info: Detects and removes spyware of different kinds (dialers, loggers, trojans, user tracks) from your computer. Blocks ActiveX downloads, tracking cookies and other threats. Over 10,000 detection files and entries. Provides detailed information about found problems.

Try: BPS Spyware and Adware Remover (http://www.bulletproofsoft.com/spyware-remover.html) This program is Shareware
Info: Adware, spyware, trackware and big brotherware removal utility with multi-language support. It scans your memory, registry and drives for known spyware and lets you remove them. Displays a list and lets you select the items you'd like to remove.

Try: Spy Sweeper v2.2 (http://www.webroot.com/wb/products/spysweeper/index.php) This program is Shareware
Info: Detects and removes spyware of different kinds (dialers, loggers, trojans, user tracks) from your computer.
The best scanner out there, and updated all the time.

Try: HijackThis 1.97.7 (http://www.spywareinfo.com/~merijn/downloads.html) This program is Freeware
Info: HijackThis is a tool, that lists all installed browser add-on, buttons, startup items and allows you to inspect them, and optionally remove selected items.

If you would like to prevent "spyware" being install.
Try: SpywareBlaster 2.6.1 (http://www.wilderssecurity.net/spywareblaster.html) This program is Free
Info: SpywareBlaster doesn`t scan and clean for so-called spyware, but prevents it from being installed in the first place. It achieves this by disabling the CLSIDs of popular spyware ActiveX controls, and also prevents the installation of any of them via a webpage.

Try: SpywareGuard 2.2 (http://www.wilderssecurity.net/spywareguard.html) This program is Free
Info: SpywareGuard provides a real-time protection solution against so-called spyware. It works similar to an anti-virus program, by scanning EXE and CAB files on access and alerting you if known spyware is detected.

Try: XP-AntiSpy (http://www.xp-antispy.org/) This program is Free
Info: XP-AntiSpy is a small utility to quickly disable some built-in update and authentication features in WindowsXP that may rise security or privacy concerns in some people.

Try: SpySites (http://camtech2000.net/Pages/SpySites_Prog...ml#SpySitesFree) This program is Free
Info: SpySites allows you to manage the Internet Explorer Restricted Zone settings and easily add entries from a database of 1500+ sites that are known to use advertising tracking methods or attempt to install third party software.

If you would like more Information about "spyware".
Check these sites.
http://www.spychecker.com/
http://www.spywareguide.com/
http://www.cexx.org/adware.htm
http://www.theinfomaniac.net/infomaniac/co...rsSpyware.shtml
http://www.thiefware.com/links/
http://simplythebest.net/info/spyware.html

Usefull tools...
Try: Stop Windows Messenger Spam 1.10 (http://www.jester2k.pwp.blueyonder.co.uk/j...r2ksoftware.htm) This program is Free
Info: "Stop Windows Messenger Spam" stops this Service from running and halts the spammers ability to send you these messages.

----------------------------------------------------------------------------
All these softwares will help remove and prevent evil spammers and spywares attacking your PC. I myself recommend getting "spyblaster" "s&d spybot" "spy sweeper" & "admuncher" to protect your PC. A weekly scan is also recommended

Free Virus Scan
Scan for spyware, malware and keyloggers in addition to viruses, worms and trojans. New threats and annoyances are created faster than any individual can keep up with.
http://defender.veloz.com// - 15k

Finding . is a Click Away at 2020Search.com
Having trouble finding what you re looking for on: .? 2020Search will instantly provide you with the result you re looking for by drawing on some of the best search engines the Internet has to offer. Your result is a click away!
http://www.2020search.com// - 43k

Download the BrowserVillage Toolbar.
Customize your Browser! Eliminate Pop-up ads before they start, Quick and easy access to the Web, and much more. Click Here to Install Now!
http://www.browservillage.com/ - 36k