Wednesday, 22 November 2017

Electrocardiogram of the Heart

An Electrocardiogram of the Heart is the recording of small electric waves being generated during heart activity. The term electrocardiograph is derived from three Greek words 'electro' meaning related to electrical activity, 'cardio' meaning heart, and 'graph' meaning to write. It is used worldwide as a simple way of diagnosing heart conditions.

Electrical activity of heart: In the heart there are specialized cells called pacemaker cells. When the heart muscle is at rest, the pacemaker cells are negatively charged and when the heart contracts they are positively charged. These cells produce small electrical signals b changing their electrical from positive to negative and back. The heart cells have the ability to spread its electrical charge to its adjacent cells. This initial trigger is enough to produce a chain reaction. Thus the electrical activity of heart starts at the top of the heart and spreads down. So this tiny electric shock spreads down to heart causing it to contract. The contraction of heart results in the pumping of blood.

For the cardiovascular system to work properly, the atria and ventricles must operate in proper time relationship. During each cycle of ECG, the action potential in the heart originates near the top of the right atrium at a point called the pace maker or sino-atrial node (SA node). Pacemakers are specialized cells that generate action potentials at a regular rate. It is necessary that to initiate the heart beat, the action potentials generated by the pacemakers propagate in all directions along the surface of atria. These propagating waves terminate at a point near the center of the heart called AV node (Atrio-ventricular node). As told earlier, the action of atria and ventricles must have a proper timing relationship. This is provided by some special fibers at the AV node. These fibers act as a delay line to provide the timing between the atria and ventricles. So after the electrical excitation passes through the delay line, it is spread rapidly to all parts of both ventricles by the bundle of His. Purkinje fibers are special fibers present in the bundle of His.

Usually heart problems can produce a wide range of symptoms. Without the help of ECG it may not be possible to tell whether the symptoms are caused by a heart problem. Symptoms are chest pain, shortness of breath, palpitations, abdominal pain, weakness etc. In some cases ECG reveals a problem that is not cardiac in nature. Ex: Overdose of certain drugs, electrolyte abnormalities etc.

Saturday, 18 November 2017

E-commerce - Challenges, Security Issues, Fundamentals


Traditional commerce is the term used for the local buying and selling of products. here there is no intermediary service such as internet or others. Some of the products involved in sale or purchase are fashion clothing, food products, jewelry and other products which are available in the local market. While in a E-commerce, sale or purchase of books, online CD'S, delivery of software, advertising and promotion of travel and other services takes place. Also online tracking of shipments is done through E-commerce.

But we can also combine both traditional commerce and E-commerce. The combination of both includes online banking, sale or purchase of automobiles and insurance products. Investment can be also done through the traditional and electronic commerce.


E-commerce can help to increase the profit that is increasing sales and decreasing cost. Some of the challenges faced by e-commerce is explained below.

E-commerce can help to increase the profit, that is increasing sales and decreasing cost. The advertisement provided on the web can help small industries for the purpose of promotion. It will reach all the customers in the world. This help in the increased sale and thus the cost of product can be reduced. Also, the business can use e-commerce in their purchasing process to identify the new suppliers and business parties. This is also a challenge faced by an E-commerce. When we create a site for the purpose of E-commerce, the following factors should be considered.
1. Why do we need to create a site?
2. Who is the visitor for the site?
3. Why do we want our own website for E-Commerce?


Security issues in E-commerce can be classified according to secrecy, integrity and necessity.

1. Necessity Threats: This type of threats will happen due to delay or denial threat. It will disrupt the normal computer processing. A computer that has affected necessity threats slows the processing speed.
2. Secrecy Threats: It is one of the most high security threat. It prevents the unauthorized information disclosure. But the privacy is to the protection of individual rights to non disclosure.
Example: Sniffer programs.
3. Integrity Threats: Unprotected banking transactions are a type of integrity threat. Here the deposited amount transmitted over the internet may sometimes subject to integrity violations may leads to integrity threat.
Example: Cyber Vandalism (replacing data with porn or others).


E-Commerce not only helps to increase the profit by increasing sales and decreasing cost. But also increases the purchasing opportunities for the buyer. This process helps to identify new parties and business suppliers. Thus negotiation of price and delivery terms can be made easier. This is one of the success factors for E-Commerce. Another factor is the buyer can select from a wide range of choices and information available about the product in the web. Also they can customize the level of details about a particular product.

The involvement of E-commerce in the social welfare is also a success factor for the E-commerce. The welfare of the society includes tax refunds, public retirement and so on. This type of electronic payment helps the customer to audit and monitor. This type of transaction can be done at home. Thus we can avoid the transportation cost and save time.


1. Electronic Cash: Electronic Cash must be able to pass transparently across international borders and can be automatically converted to recipient country's currency. It must have a monetary value. Companies offering E-Cash are
a. Check Free: Check Free provides software that permits users to pay all their bills with online electronic checks.
b. Internet Cash: Merchants provide cash rather than credit cards to pay for products for online customers.
c. Pay Pal: Pay Pal provide payment processing services to business and for individuals.
d. Cyber Cash: Cyber Cash includes credit card, micro payment and check payment services.

2. Electronic Payment: Electronic Payment is the first introduced money transfer method. In Early days, it was labeled at Electronic Fund Transfer. The transfer of fund is done through electronic terminals, telephone or computers.

3. Electronic Wallets: It includes credit cards, electronic cash, owner identification and owner address information. Examples are Agile Wallet, Microsoft Wallet and E-Wallets.

4. Stored Value Cards: It consists of a microchip or a plastic card with a magnetic strip. Commonly used stored value cards include Prepaid Phone and Bus Card.
   example: Magnets strip cards, Smart Cards, Mondex Smart Card etc.

Website Development

Web Developers are the people involved in developing the website. They consists of a team of workers. Their main aim is to satisfy the client's need and to meet the expectation level of client. The web development team consists of  Web Optimizers,Web Designers,Web Programmers and Content Writers. The main duty of designers is to design the web page. They produce prototypes. Dynamic programming section belongs to Web programmers. Content writers write the contents for the website. Web Optimizers optimize the web pages.

Each Worker in the Web Development Company should have their own duty.The web designers produce the prototypes according to the client's need.They design the pages beautifully to attract the visitors.Content Writers write the contents for the website..They construct the sentences simply in order to understand the visitors quickly.Programming is an important part in website development and is done by the web programmers.Optimization is done by the Web Optimizers.Optimizers are the key people in website development.Their duty is to increase the page rank.

Web developers work in co-operation in order to fulfill clients demand.The prototypes built by the developers are reviewed by the team workers and send to client.After demonstration,client will send the feedback of website.According to the feedback,they redesign the web page.After designing ,programming and content writing,optimization for website is done.