Transcript Voice over Internet Protocol (VoIP)

VOIP: Voice over Internet
Protocol
Broadband Phone Services
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Introduction
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Voice over Internet Protocol (VoIP) is a protocol optimized for the
transmission of voice through the Internet or other packet switched
networks.
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VoIP is often used abstractly to refer to the actual transmission of voice
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VoIP is also known as IP Telephony, Internet telephony, Broadband
telephony, Broadband Phone and Voice over Broadband.
VoIP is the ability to make telephone calls over IP-based data networks
with a suitable quality of service and superior cost-efficiency.
www.about.com
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Introduction
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VoIP converts analog voice signals into digital data packets and
supports real-time, two-way transmission of conversations using
Internet protocol.
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VoIP calls can be made on the Internet using a VoIP service provider
and standard computer audio systems. Some service providers support
VoIP through ordinary telephones that use special adapters to connect
to a home computer network.
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Broadband Phone Service
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Broadband phone service [3]
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Enables voice telephone calls to work over your
high-speed Internet connection.
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A broadband phone (also known as a VoIP or
Internet phone) utilizes the same IP network as
your Internet service.
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Hardware adapters connect a standard telephone
to the high-speed Internet connection to create a
broadband phone.
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Broadband Phone Service
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Hardware and software broadband phones are
available [3].
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Hardware broadband phones use an adapter (either as an
add-on to your traditional phone or built in to an all-in-one
phone unit).
The hardware is then connected to either the router on your
network (via Ethernet) or your PC (via USB).
Software broadband phones use a software program to
make broadband calls.
http://qwest.centurylink.com/residenti
al/products/voip/how_it_works.html
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Broadband Phone Service Plans
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Service providers offer many different broadband
phone subscription plans [3].
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As with a cell phone, some service plans for these
telephones feature unlimited local calling or large numbers
of free minutes.
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The cost of broadband phone service is highly variable;
international, long distance and other calling charges often
still apply.
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Broadband Phone Reliability
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Compared to an Internet-based broadband phone
network, the standard home voice telephone
network is extremely reliable [3].
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Calls cannot be made with the broadband phone whenever
your home Internet service is down.
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Additional failures within the broadband phone service itself
will add to any downtime caused by the Internet connection.
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Broadband Phone Sound Quality
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The sound quality supported by broadband phone
service was significantly less than with traditional
telephone services [3].
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It can vary by provider and location, in general the quality
of broadband phone audio is very good.
You might notice a small delay ("lag") between when you
speak and the other party hears your voice.
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Why choose VoIP
[2]
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Why choose VoIP
[2]
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Why choose VoIP
[2]
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Why choose VoIP
[2]
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Why choose VoIP
[2]
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Why choose VoIP [1]
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Cost reduction.
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Consolidation.
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The ability to eliminate points of failure, consolidate accounting systems and
combine operations is obviously more efficient.
Simplification.
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There can be a real savings in long distance telephone costs which is
extremely important to most companies, particularly those with international
markets.
An integrated voice/data network allows more standardization and reduces
total equipment needs.
Bandwidth efficiency:
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PSTN networks reserve one pipe for every call. But in IP networks many
calls can use the same pipe simultaneously.
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Why choose VoIP [1]
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Important problems of fixed line
telephony:
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Limited extension of PBX
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Imperfect simultaneous calls
number
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No common local (short) numbers
between branches
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Slow installation of changes in all
telephony system – maintenance is
done of few companies (cabling,
PBX changes, system changes);
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Advantages of fixed line telephony
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Well tried quality of calls, services
Well known technology
Limited ability to transfer, forward
calls;
Paid calls between branches;
Slow and expensive installation
when moving to new office;
No possibility to integrate
telephony system with computer
systems.
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Why choose VoIP [1]
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Advantages of VoIP
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Extra functions (conversations recording, statistics of calls.
Faster and cheaper installation of the system
Portability
Integration with computer systems
Free calls between company’s branches
Free calls in your network
Lower subscription fees
You can use your current LAN – no need to change infrastructure;
No limit to simultaneous calls
Not limited number of users connected to PBX
Remote and fast maintenance
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References
[1] www.gmsvoip.com
[2] Peter Ingram, “Voice over Internet Protocol
(VoIP) - An Introduction”, Ofcom, 18th
January 2005.
[3] www.about.com
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e-Commerce
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How to enhance e-Commerce sales?
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Browsers into buyers
Cross-sell
Recommender Systems!!
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What are recommender systems?
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Recommender systems are systems which provide
recommendations to a user
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Too much information (information overload)
Users have too many choices
Recommend different products for users, suited to
their tastes.
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Assist users in finding information
Reduce search and navigation time
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Case Study: Amazon
www.amazon.com
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Personalized Product
Recommendation?
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Which Sources of Information?
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Sources of information for recommendations:
[1]
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Browsing and searching data
Purchase data
Feedback provided by the users
Textual comments
Expert recommendations
E-mail
Rating
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Type of Recommendations [2]
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Population-based
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The most popular news articles, or searches, or
downloads
Frequently add content
No user tracking needed.
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Type of Recommendations [2]
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Item-to-item
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Content-based
One item is recommended based on the user’s
indication that they like another item.
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If you like Lord of the Rings, you’ll like Legend.
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Type of Recommendations [2]
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Challenges with item-to-item:
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Getting users to tell you what they like
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Financial and time reasons
Getting enough data to make “novel” predictions.
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What users really want are recommendations for things
they’re not aware of.
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Type of Recommendations [2]
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Item-to-item
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Most effective when you have metadata that lets
you automatically relate items.
Genre, actors, director, etc.
Also best when decoupled from payment
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Users should have an incentive to rate items
truthfully.
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Type of Recommendations [2]
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User-based
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“Users who bought X like Y.”
Each user is represented by a vector indicating
his ratings for each product.
Users with a small distance between each other
are similar.
Find a similar user and recommend things they
like that you haven’t rated.
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Type of Recommendations [2]
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User-based
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Advantages:
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Users don’t need to rate much.
No info about products needed.
Easy to implement
Disadvantages
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Pushes users “toward the middle” – products with more
ratings carry more weight.
How to deal with new products?
Many products and few users -> lots of things don’t get
recommended.
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References
[1] Aalap Kohojkar, Yang Liu, Zhan Shi, “Recommender Systems”, March 31, 2008.
[2] Maria Fasli, “Agent Technology for e-Commerce”, http://cswww.essex.ac.uk/staff/mfasli/ATeCommerce.htm
[3] Amit Tiroshi, Tsvi Kuflik, Judy Kay and Bob Kummerfeld, “Recommender Systems and the Social Web”,
International Workshop at UMAP2011 on Augmenting User Models with Real World Experiences to
Enhance Personalization and Adaptation, July 15, 2011.
[4] Xiaoyuan Su, Taghi M. Khoshgoftaar, “A Survey of Collaborative Filtering Techniques”, Advances in
Artificial Intelligence, Vol. 2009, 2009.
[5] Badrul M. Sarwar, George Karypis , Joseph Konstan, and John Riedl, “Recommender Systems for Largescale E-Commerce: Scalable Neighborhood Formation Using Clustering”, The Fifth International
Conference on Computer and Information Technology (ICCIT 2002) , 2002.
[6] Louis E. Frenzel, Jr., “Principles of Electronic Communication Systems”, The third edition, McGraw-Hill,
2008.
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