why the frequency and voltage in india is 230v and 50HZ. when compared to USA say 110v and 60 HZ.

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4 down vote favorite share [g+] share [fb] share [tw] I am developing my site using server side sessions using redis as backend for saving the session. Now the issue which is bothering me is of user leaving the website without logging out. I mean user simply closes the browser which causes the cookie to be deleted. Now session of that user still exists on the server and will not be used again as new login requires creating a new session due to security reasons. To avoid the case where hacker steals the old cookie and use it after user login again with same old session id. In essence user leaves the website without explicitly logging out and his session will be deleted after certain time limit of inaccessibility. I am thinking time limit of 30-60 minutes. Also with every new request from user his cookie will also be updated to keep track of when the user last time accessed the site. But nowadays, people let site remain open for long time without accessing it. For example users open facebook and gmail in new tabs and forget about them for 2-3 hours and still they are not asked to login again. Is letting a 2-3 hours old cooke access the session secure? My concern is someone steals user cookie and use it 2-3 hours later. Thinking on this topic has also forced me to question how facebook manages security if user can use a session where they are not accessing it for long periods of time and still they remain logged in. Or is it not secure for me to keep logged in when am not accessing the site session for longer period of time? It can be the case also there is some pinging mechanism using which sites keep track of user having their site open in a browser and when browser closes they are notified and can work accordingly. My website is a social network and needs all those security and usage features which a social network may need. I am new to web security and web development in general and may be the case where my above questions may seem a little basic. If you feel that is the case kindly point to some good reference where I can read and find answers to my question.

1066

What is the use of Imagelist Controls ?

738

How we will do Memory Testing? There is any tool to do that testing and to whome this testing to be performed?

722

what is error and fault in terms of software quality?

773

how is data partitioned before it is sent to the reducer if no custom partitioner is defined in Hadoop?

10

What are the recording modes in wave event?

723

Why did you choose this Mechanical Engineering Carrier? What goals do you have in your carrier? How do you plan to achieve these goals?

1149

are there rmu for 3 transformer?

552

a private address 172.116.0.0 will borrow ? bits from the HOST to give one 120 subnets - range = ?

1112

What collections you have worked on? Internal working of Hashmap?

1059

Please let me know what to answer how long you prepared for SBI exam? if selected your credit goes to whom?

782

What is the defination of job costing, batch costing and contract costing?

2903

what is the age limit for groups1 examination

940

Tell me what you know about Web UI customizing? How can we edit labels?

1465