(i) E-Commerce also has some limitations. The following are the major drawbacks of E-Commerce for a business organization.
(ii) In E-Commerce, the customer should wait between placing the order and having the product in hand.
(iii) The doubts about the period of returning, will the returned goods reach source in time, refunds, exchange, and postage make one tiresome.
(iv) Privacy issues are serious in E-Commerce.
(v) In E-Commerce generating consumer information is inevitable. Not all the companies use the personal information they obtained to improve services to consumers.
(vi) Many companies misuse the information and make money out of it.
(vii) It is true that privacy concerns are a critical reason why people get cold feet about online shopping Physical product disputes are a major disadvantage in E-Commerce.
(viii) In online shopping, we would see only the pictures the seller had chosen for us.
(ix) The Internet needs to survive the trip from the supplier to the consumer. This makes the customers turn back towards traditional supply chain arrangements.
(x) It is pretty hard to knock on their door to complain or seek legal recourse. Further, even if the item is sent, it is easy to. start bothering whether or not it will ever arrive on time. 

(i) OSS is slightly different from free software.
(ii) Both deal with the ability to download and modify software without restriction or charge.
(iii) In contrast, the OSS criteria, which the Open Source Initiative developed a decade later, place more emphasis on the modification of software, and the consequences of altering source code, licensing, and distribution.
(iii) Obviously, the two overlap; some would say the differences between OSS and free software are more philosophical than practical.
(iv) However, neither should be confused with freeware.
(v) Freeware usually refers to proprietary software that users can download at no cost, but the whose source code cannot be changed.

Network simulation
In a computer network, network simulation is a method whereby a software program models the activities of a network by calculating the communication between the different network objects such as(routers, nodes, switches, access points, links, etc.).
Network simulator
(i)  A network simulator is a software program that replicates the functioning of a computer network.
(ii) In simulators, the computer network is typically demonstrated with devices, traffic, etc. and the performance is evaluated.
Normally, users can then adapt the simulator to accomplish their precise analysis needs.
Network Parameters:
The network parameters define the state of the network (node placement, existing links) and the events (data transmissions, link failures, etc.).
Trace files:
A significant output of the simulation is the trace files. Trace files can document every incident that happened in the simulation and are used for examination.
NS2: NETWORK SIMULATOR version 2.
(i) It was considered explicitly for exploration in network communication and event-driven opensource simulator in computer.
(ii) OTCL and C++ used to create and run NS2.
(iii) NS2 works on Windows and Linux platforms that support wired or wireless network and also use the command line interface as a user interface.
API:
(i) API a pure event base software tool with super simulation design, it has more models which help the user to get desired output easily.

Step 1: Login to net banking account using unique user name and password provided by the bank earlier.
Step 2: Add the beneficiary as a payee to enable transfer of fund. The following details like Account Number, Name, IFSC about the beneficiary' are to be filled in the 'Add New Payee'section.
Step 3: Once the beneficiary is added, choose RTGS/ NEFT/ IMPS as mode of Fund Transfer.
Step 4: Select the account to transfer money from, select the payee, enter the amount to be transferred and add remarks (optional).
Step 5: Click on submit.
Step 6: Enter the OTPreceivedto mobile number linked to the corresponding account to complete the transaction.

1. Credit card number: The modern credit card number has 16-digit unique identification number.
2. The first digit of the credit card number is Major Industry Identifier (MII).
i) It identifies the issuer category.
ii) e.g. 1 - Airlines,4 - Banks
3. The next 5 digits uniquely identify the issuing organization
4. The first 6 digits together called as Issuer Identifier number (IlN) or Bank Identification number (BIN).
5. The next 9 digits are the account number.
6. The last digit is a check digit (based to the Luhn algorithm).

Default Syntax:
The default Syntax begins with " < ?php"and closes with "? > ".

Short open Tags
(i) The Short open Tags begins with " < ?" andcloses with "? > " .
(ii) But admin user has to enable Short style tags settings in php.ini file on the server.

HTML Script embed Tags:
HTML Script embed Tags looks just like HTML scripts tags.

1. Primary Key:
(i) This key of relational table identifies each record in the table in a unique way.
(ii) A primary key which is a combination of more than one attribute is called a composite primary key.
(iii) The candidate key that is chosen to perform the identification task is called the primary key
2. Foreign Key:
(i) A foreign key is a "copy" of a primary keythat has been exported from one relation into another to represent the existence of a relationship between them
(ii) A foreign key is a copy of the whole of its parent primary key i.e if the primary key is composite, then so is the foreign key.
(iii) Foreign key values do not (usually) have to be unique.
(iv) Foreign keys can also be null.
(v) A composite foreign key cannot have some attribute(s) null and others non-null.
3. Candidate Key:
(i) Each super key is called a candidate key.
(ii) A candidate key is selected from the set of Super Key.
(iii) While selecting candidate key, redundant attributes should not be taken.
(iv) The candidate key is also known as minimal super keys.
4. Super Key:
(i) An attribute or group of attributes, which is sufficient to distinguish every tuple in the relation from every other one is known as Super Key.
5. Composite Key (Compound Key):
(i) A key with more than one attribute to identify rows uniquely in a table is called Composite key.
(ii) This is also known as Compound Key.

To make page numbers appear on every page
1. Click on Master Pages icon.
2. Then click on Text Tool. Now the cursor changes to I - beam.
3. Then Click on the left Master page where you want to put the page number.
4. Press Ctrl + Alt + P.
5. The page number displays as 'LM' on the left master page.
6. Similarly click on the right master page where you want to put the page number.
7. Press Ctrl + Alt + P.
8. The page number displays as 'RM' on the right master page, but will appear correctly on the actual pages

Filling Rectangle with colour
1. Draw a rectangle using Rectangle tool.
2. Select the rectangle.
3. Choose Window > Show colors inthe menu bar. (or) Press Ctrl + J. Now Colors palette appears.
4. Click on the required colour from the Colors Palette.
5. The rectangle has been filled with the colour

1. Double click the Line tool from the toolbox. A Custom Stroke dialogue box appears.
2. Select the required Stroke style in the drop-down list box.
3. Then click OK button. Now the cursor changes to a crosshair.
4. Click and drag on the screen to draw your dotted line. As you drag, the line appears
5. Release the mouse button and the line will be drawn and selected, with sizing handles on either end. Resize the line by clicking and dragging the handles, if necessary.

Use the zoom tool to magnify or reduce the display of any area in your publication
To magnify or reduce with the zoom tool
1. Select the zoom tool. The pointer becomes a magnifying glass with a plus sign in its center, indicating that the zoom tool will magnify your view of the image. To toggle between magnification and reduction, press the Ctrl key.
2. Position the magnifying glass at the center of the area you want to magnify or reduce, and then click to zoom in or out. Continue clicking until the publication is at the magnification level you want. When the publication has reached its maximum magnification or reduction level, the center of the magnifying glass appears blank.
To magnify part of a page by dragging:
1. Select the zoom tool.
2. Drag to draw a marquee around thearea you want to magnify
To zoom in or out while using another tool:
Press Ctrl+Spacebar to zoom in. Press Ctrl + Alt + Spacebar to zoom out.

Method - 1:
(i) Select the blcok that you wish to unthread with the pointer tool. Click on Edit > Cut in the menu bar. (the block disappear).
(ii) Now click on the Edit ⟶ Paste in the menu bar.
(iii) The block will reappear in the same position, but it is now an unthreaded block
Method - 2:
(i) Select the block that you wish to unthread with the pointer tool
(ii) Then choose the Text tool and select all the menu bar.(the blok disappear).
(iii) Now click the insertion point within an existing threaded block.
(iv) Then click on Edit ⟶ Paste in the menu bar.
(v) The text will be added in this block.

(i) Within an E-Commerce site, there are multiple vulnerable areas that can serve as an intrusion point for a hacker to gain payment and user information.
(ii) Using malware, Cross Site Scripting or SQL Injection, an attacker will extract the credit card information and sell the acquired data on black markets.
Fraud is then committed to extract the greatest value possible through E-Commerce transactions or ATM withdrawals, etc.

(i) Tampering intentional modification of products in a way that would make them harmful to the consumer
(ii) E-Commerce has the problem of the authenticity and integrity of business information.
(iii) When hackers grasp the data transmitted on the network, it can be falsified in the middle through various technical means, and then sent to the destination, thereby destroying the authenticity and integrity of the data.

(i) To avoid the major disadvantage of Flat namespace, hierarchical namespace is used in large
(ii)  Hierarchical namespace is where the name is made up of several parts.
a. First part may represent the nature of the organization.
b. Second part may represent the name of the organization, and
c. Third part may represent the department of the organization and so on.
(iii) In this way the power to control the namespace can be decentralized.
(iv) The centralized authority can be given to nature and then to the name of the organization and so on.
(v) To achieve hierarchical namespace, Domain Name Space was designed.

(i) SG is the stage succeeds the 4G (LTE/WiMAx), 3G(umts) and 2G(GSM)syetems.
(ii) SG targets to performance the high data rate, reduced latency, energy saving, cost reduction, higher system, capacity, and massive device connectivity.
(iii) The two phasesof SG,First one will be Release-1S complete by March 2019, Second one Release- 16is expected to complete at March2020, for submission to the ITU (International Telecommunication Union) as a candidate IMT- 2020 technology.
(iv)  The ITU IMT - 2020 provides speeds up to 20 gigabits per second it has been demonstrated with millimeter waves of lS giga hertz and higher frequency. 3 GPPstandards includes any network using the New Radio software. SGNew Radio can accessat lower frequencies from 600 MHzto 6 GHz.
(v) Speed in the lower frequencies are only modest higher than 4G systems, estimated at lS% to SO%faster

(i) Third generation of mobile systems merges different mobile technology standards, and uses higher frequency bands for transmission and Code Division Multiple Access to delivery data rates of up to 2Mbit/s supports multimedia services (MMS: voice, video and data) .
(ii) European standard is UMTS(Universal Mobile Telecommunication Systems).
(iii)  Mobile phones systems continue to use digital transmission with SIM authentication for billing systems and for data incorruption.
(iv) Data transmission used a WCDMA. WCDMA stands for (Wideband Code Division Multiple Access).
(v) One technique to obtain data rates between 384kbit/s and 2048kbit/s. Few 3G suppliers use ATM (Asynchronous Transfer Mode) for their 'over the air' network with in MPLS(Multiprotocol Label Switching) or IP for theirs backbone network.
(vi) Mobility still supported at layer2, and hence like 2G it still prohibits seamless roaming beyond heterogeneous access networks and routing domains.
(vii) The transmission were band frequencies are between 1900 and 2200 MHz. All UMTS license holders at the UK holds a 20-year license with the condition that 80% population coverage is achieved by 31 December 2007.
(viii) The present third generation licensed operators in the UK can be seen below as at August 2004.

The Internet Explosion
(i) Internet is simply defined as the World Wide Web connection of individual networks which operated by academic, industry, government, and private parties.
(ii)  The Internet served to interconnect with laboratories engaged at government research, and from 1994 it is expanded to serve millions of user and a multiple purpose in all parts of this universe.
(iii) In few years, the Internet built itself as a highly powerful platform that changed their way we do business and the way we communicate. Internet promotes as the universal source of information of billions of people, at work, at home, at school. Internet gave high communication medium, has given an international, "Globalised" at all dimension of the world.
(iv) Internet is growing all the time. By two things, have marked its evolution nowadays the mobile technology and social web. These two innovations have been changed the people life style to use Internet. We may find many communities in social web. Facebook was created in 2004 but gowned into world wide network all over more than 2,230 million active users.
(v) Mobile technology on hand made possible to great reach of Internet and increase the Internet user all over the world.
(vi) The Internet allows all to be democratic in mass media. Anyone can have a webpage in
(vii) Internet with very low investment. Similarly any business can reach a very large market directly, economically and fast, no matter of location or size of their business. Almost anyone that who san read and write can have a access and a presence in World Wide Web with very low investment. People everywhere can express and publish their ideas and opinions via blogging.

< ?php
＄n = "February";
switch(＄n) {
case "January":
echo "Its January";
break;
case "February":
echo "Its February";
break;
case "March":
echo "Its- March";
break;
case "April":
echo "Its April";
break;
case "May":
echo "Its May";
break;
case "June":
echo "Its June";
break;
case "July":
echo "Its July";
break;
case "August":
echo "Its August";
break;
case "September":
echo "Its September";
break;
case "October":
echo "Its October";
break;
case "November":
echo "Its November";
break;
case "December":
echo "Its December";
break;
default:
echo "Doesn't exist";
}
? >

(i) Four Parameters are used to connect to the Database server.
(ii) They are
1.＄ servername -> Database Server server IP address
2.＄ susername -> Database Server User Name
3.＄ password -> Database Server Password
4.＄ DB_Name -> Database Name