Second-generation (2G) mobile systems were very successful in the previous decade. Their success prompted the development of third generation (3G) mobile systems. While 2G systems such as GSM, IS-95, and cdmaOne were designed to carry speech and low-bit-rate data, 3G systems were designed to provide higher-data-rate services. During the evolution from 2G to 3G, a range of wireless systems, including GPRS, IMT-2000, Bluetooth, WLAN, and HiperLAN, have been developed. All these systems were designed independently, targeting different service types, data rates, and users. As all these systems have their own merits and shortcomings, there is no single system that is good enough to replace all the other technologies. Instead of putting efforts into developing new radio interfaces and technologies for 4G systems, which some researchers are doing, we believe establishing 4G systems that integrate existing and newly developed wireless systems is a more feasible option.
Researchers are currently developing frameworks for future 4G networks. Different research programs, such as Mobile VCE, MIRAI, and DoCoMo, have their own visions on 4G features and implementations. Some key features (mainly from user's point of view) of 4G networks are stated as follows:" High usability: anytime, anywhere, and with any technology" Support for multimedia services at low transmission cost" Personalization" Integrated servicesFirst, 4G networks are all IP based heterogeneous networks that allow users to use any system at any time and anywhere. Users carrying an integrated terminal can use a wide range of applications provided by multiple wireless networks.
Second, 4G systems provide not only telecommunications services, but also data and multimedia services. To support multimedia services, high-data-rate services with good system reliability will be provided. At the same time, a low per-bit transmission cost will be maintained.
Third, personalized service will be provided by this new-generation network. It is expected that when 4G services are launched, users in widely different locations, occupations, and economic classes will use the services. In order to meet the demands of these diverse users, service providers should design personal and customized services for them.
Finally, 4G systems also provide facilities for integrated services. Users can use multiple services from any service provider at the same time. Just imagine a 4G mobile user, Mary, who is looking for information on movies shown in nearby cinemas. Her mobile may simultaneously connect to different wireless systems. These wireless systems may include a Global Positioning System (GPS) (for tracking her current location), a wireless LAN (for receiving previews of the movies in nearby cinemas), and a code-division multiple access (CDMA) (for making a telephone call to one of the cinemas). In this example Mary is actually using multiple wireless services that differ in quality of service (QoS) levels, security policies, device settings, charging methods and applications. It will be a significant revolution if such highly integrated services are made possible in 4G mobile applications.
To migrate current systems to 4G with the features mentioned above, we have to face a number of challenges. In this article these challenges are highlighted and grouped into various research areas. An overview of the challenges in future heterogeneous systems will be provided. Each area of challenges will be examined in detail. The article is then concluded.
Thursday, June 11, 2009
Friday, March 20, 2009
Mobile agent
In computer science, a mobile agent is a composition of computer software and data which is able to migrate (move) from one computer to another autonomously and continue its execution on the destination computer.
Mobile Agent, namely, is a type of software agent, with the feature of autonomy, social ability, learning, and most important, mobility.
When the term mobile agent is used, it refers to a process that can transport its state from one environment to another, with its data intact, and still being able to perform appropriately in the new environment. Mobile agents decide when and where to move next, which is evolved from RPC. So how exactly does a mobile agent move? Just like a user doesn t really visit a website but only make a copy of it, a mobile agent accomplishes this move through data duplication. When a mobile agent decides to move, it saves its own state and transports this saved state to next host and resume execution from the saved state.
Mobile agents are a specific form of mobile code and software agents paradigms. However, in contrast to the Remote evaluation and Code on demand paradigms, mobile agents are active in that they may choose to migrate between computers at any time during their execution. This makes them a powerful tool for implementing distributed applications in a computer network.
Advantages
1) Move computation to data, reducing network load.
2) Asynchronous execution on multiple heterogeneous network hosts
3) Dynamic adaptation - actions are dependent on the state of the host environment
4) Tolerant to network faults - able to operate without an active connection between client and server
5) Flexible maintenance - to change an agent s actions, only the source (rather than the computation hosts) must be updated
Applications
1) Resource availability, discovery, monitoring
2) Information retrieval
3) Network management
4) Dynamic software deployment
Mobile Agent, namely, is a type of software agent, with the feature of autonomy, social ability, learning, and most important, mobility.
When the term mobile agent is used, it refers to a process that can transport its state from one environment to another, with its data intact, and still being able to perform appropriately in the new environment. Mobile agents decide when and where to move next, which is evolved from RPC. So how exactly does a mobile agent move? Just like a user doesn t really visit a website but only make a copy of it, a mobile agent accomplishes this move through data duplication. When a mobile agent decides to move, it saves its own state and transports this saved state to next host and resume execution from the saved state.
Mobile agents are a specific form of mobile code and software agents paradigms. However, in contrast to the Remote evaluation and Code on demand paradigms, mobile agents are active in that they may choose to migrate between computers at any time during their execution. This makes them a powerful tool for implementing distributed applications in a computer network.
Advantages
1) Move computation to data, reducing network load.
2) Asynchronous execution on multiple heterogeneous network hosts
3) Dynamic adaptation - actions are dependent on the state of the host environment
4) Tolerant to network faults - able to operate without an active connection between client and server
5) Flexible maintenance - to change an agent s actions, only the source (rather than the computation hosts) must be updated
Applications
1) Resource availability, discovery, monitoring
2) Information retrieval
3) Network management
4) Dynamic software deployment
Thursday, March 19, 2009
Open GPS Tracker
The Open GPS Tracker is a small device which plugs into a $20 prepaid mobile phone to make a GPS tracker. The Tracker responds to text message commands, detects motion, and sends you its exact position, ready for Google Maps or your mapping software. The Tracker firmware is open source and user-customizable.
The current supported hardware platform is:
* Tyco Electronics A1035D GPS module
* Motorola C168i AT&T GoPhone prepaid mobile phone
* Atmel ATTINY84-20PU AVR microcontroller
Project requires no interfacechips! All you need is a GPS module, a phone, an ATTINY84, a voltage regulator, a PNP transistor, and a few passive components. This is a commercial grade tracker and is currently a second-generation stable beta V0.17.
This version stores messages while out of GSM coverage, and forwards them when it regains coverage.
Introduction |
Welcome to the Open GPS Tracker site. The Open GPS Tracker is a small device which plugs into a $20 prepaid mobile phone to make a GPS tracker. The Tracker responds to text message commands, detects motion, and sends you its exact position, ready for Google Maps or your mapping software
. The Tracker firmware
Project status: We currently have second-generation stable firmware and a reference hardware design. All parts are available from Mouser Electronics, and the phone is available from Target, Walmart, or Radio Shack. This site provides the firmware with source code, theory of operation, parts list, and exact assembly and checkout instructions. If you can solder, this is a one-sitting project. No PC board or surface-mount capability is required.
Programmed parts will be available as soon as the firmware is out of beta. We intend to have kits and assembled units available for purchase shortly thereafter. Commercial products are planned, but the firmware will remain open source.
The current supported hardware platform is:
Tyco Electronics A1035D GPS module
Motorola C168i AT&T GoPhone prepaid mobile phone
Atmel ATTINY84-20PU AVR microcontroller
We intend to support
more phones and GPS devices in the future.
The Tracker's features are competitive with, or better than, many commercial products:
SiRFstar III receiver gets a fix inside most buildings.
Sends latitude, longitude, altitude, speed, course, date, and time.
Sends to any SMS-capable mobile phone, or any email address.
Battery life up to 14 days, limited by mobile phone. Longer life possible with external batteries.
GoPhone costs $10 per month for 1000 messages per month.
Configurable over-the-air via text message commands.
Password security and unique identifier.
Manual locate and automatic tracking modes controlled via text message.
Automatic tracking mode sends location when the tracker starts moving,
when it stops moving, and at programmable intervals while moving.Alerts when user-set speed limit is exceeded.
Retains tracking messages if out of coverage, and sends when back in coverage.
Retains and reports last good fix if it loses GPS coverage.
Remote reporting of mobile phone battery and signal status.
Extended runtime mode switches phone on and off to save battery life.
Watchdog timer prevents device lockup.
Firmware is user-customizable with a $35.91 programmer and free software.
In addition to being a GPS tracker, the firmware is easily modified to monitor
and control anything from a weather station to a vending machine via text messaging.
Smart NoteTaker
The Smart NoteTaker is such a helpful product that satisfies the needs of the people in today's technologic and fast life. This product can be used in many ways. The Smart NoteTaker provides taking fast and easy notes to people who are busy one's self with something. With the help of Smart NoteTaker, people will be able to write notes on the air, while being busy with their work. The written note will be stored on the memory chip of the pen, and will be able to read in digital medium after the job has done. This will save time and facilitate life.
The Smart NoteTaker is good and helpful for blinds that think and write freely. Another place, where our product can play an important role, is where two people talks on the phone. The subscribers are apart from each other while their talk, and they may want to use figures or texts to understand themselves better. It's also useful especially for instructors in presentations. The instructors may not want to present the lecture in front of the board. The drawn figure can be processed and directly sent to the server computer in the room. The server computer then can broadcast the drawn shape through network to all of the computers which are present in the room. By this way, the lectures are aimed to be more efficient and fun. This product will be simple but powerful. The product will be able to sense 3D shapes and motions that user tries to draw. The sensed information will be processed and transferred to the memory chip and then will be monitored on the display device. The drawn shape then can be broadcasted to the network or sent to a mobile device.
There will be an additional feature of the product which will monitor the notes, which were taken before, on the application program used in the computer. This application program can be a word document or an image file. Then, the sensed figures that were drawn onto the air will be recognized and by the help of the software program we will write, the desired character will be printed in the word document. If the application program is a paint related program, then the most similar shape will be chosen by the program and then will be printed on the screen.
Since, JAVA Applet is suitable for both the drawings and strings, all these applications can be put together by developing a single JAVA program. The JAVA code that we will develop will also be installed on the pen so that the processor inside the pen will type and draw the desired shape or text on the display panel.
The Smart NoteTaker is good and helpful for blinds that think and write freely. Another place, where our product can play an important role, is where two people talks on the phone. The subscribers are apart from each other while their talk, and they may want to use figures or texts to understand themselves better. It's also useful especially for instructors in presentations. The instructors may not want to present the lecture in front of the board. The drawn figure can be processed and directly sent to the server computer in the room. The server computer then can broadcast the drawn shape through network to all of the computers which are present in the room. By this way, the lectures are aimed to be more efficient and fun. This product will be simple but powerful. The product will be able to sense 3D shapes and motions that user tries to draw. The sensed information will be processed and transferred to the memory chip and then will be monitored on the display device. The drawn shape then can be broadcasted to the network or sent to a mobile device.
There will be an additional feature of the product which will monitor the notes, which were taken before, on the application program used in the computer. This application program can be a word document or an image file. Then, the sensed figures that were drawn onto the air will be recognized and by the help of the software program we will write, the desired character will be printed in the word document. If the application program is a paint related program, then the most similar shape will be chosen by the program and then will be printed on the screen.
Since, JAVA Applet is suitable for both the drawings and strings, all these applications can be put together by developing a single JAVA program. The JAVA code that we will develop will also be installed on the pen so that the processor inside the pen will type and draw the desired shape or text on the display panel.
Data Compression Techniques
Data Compression Techniques
Data compression is the procces of converting an input data stream or the source stream or the original raw data into another data stream that has a smaller size. data compression is popular because of two reasons
1) People like to accumulate data and hate to throw anything away. No matter however large a storage device may be, sooner or later it is going to overflow. Data compression seems useful because it delays this inevitability2) People hate to wait a long time for data transfer. There are many known methods of data compression. They are based on the different ideas and are suitable for different types of data.
They produce different results, but they are all based on the same basic principle that they compress data by removing the redundancy from the original data in the source file. The idea of compression by reducing redundancy suggests the general law of data compression, which is to "assign short codes to common events and long codes to rare events". Data compression is done by changing its representation from inefficient to efficient form.
The main aim of the field of data compression is of course to develop methods for better and better compression. Experience shows that fine tuning an algorithm to squeeze out the last remaining bits of redundancy from the data gives diminishing returns. Data compression has become so important that some researches have proposed the "simplicity and power theory". Specifically it says, data compression may be interpreted as a process of removing unnecessary complexity in information and thus maximizing the simplicity while preserving as much as possible of its non redundant descriptive power.Basic Types Of Data Compression
There are two basic types of data compression.
1. Lossy compression
2. Lossless compression
Lossy Compression: In lossy compression some information is lost during the processing, where the image data is stored into important and unimportant data. The system then discards the unimportant dataIt provides much higher compression rates but there will be some loss of information compared to the original source file. The main advantage is that the loss cannot be visible to eye or it is visually lossless. Visually lossless compression is based on knowledge about colour images and human perception.
Lossless Compression: In this type of compression no information is lost during the compression and the decompression process. Here the reconstructed image is mathematically and visually identical to the original one. It achieves only about a 2:1 compression ratio. This type of compression technique looks for patterns in strings of bits and then expresses them more concisely.
Data compression is the procces of converting an input data stream or the source stream or the original raw data into another data stream that has a smaller size. data compression is popular because of two reasons
1) People like to accumulate data and hate to throw anything away. No matter however large a storage device may be, sooner or later it is going to overflow. Data compression seems useful because it delays this inevitability2) People hate to wait a long time for data transfer. There are many known methods of data compression. They are based on the different ideas and are suitable for different types of data.
They produce different results, but they are all based on the same basic principle that they compress data by removing the redundancy from the original data in the source file. The idea of compression by reducing redundancy suggests the general law of data compression, which is to "assign short codes to common events and long codes to rare events". Data compression is done by changing its representation from inefficient to efficient form.
The main aim of the field of data compression is of course to develop methods for better and better compression. Experience shows that fine tuning an algorithm to squeeze out the last remaining bits of redundancy from the data gives diminishing returns. Data compression has become so important that some researches have proposed the "simplicity and power theory". Specifically it says, data compression may be interpreted as a process of removing unnecessary complexity in information and thus maximizing the simplicity while preserving as much as possible of its non redundant descriptive power.Basic Types Of Data Compression
There are two basic types of data compression.
1. Lossy compression
2. Lossless compression
Lossy Compression: In lossy compression some information is lost during the processing, where the image data is stored into important and unimportant data. The system then discards the unimportant dataIt provides much higher compression rates but there will be some loss of information compared to the original source file. The main advantage is that the loss cannot be visible to eye or it is visually lossless. Visually lossless compression is based on knowledge about colour images and human perception.
Lossless Compression: In this type of compression no information is lost during the compression and the decompression process. Here the reconstructed image is mathematically and visually identical to the original one. It achieves only about a 2:1 compression ratio. This type of compression technique looks for patterns in strings of bits and then expresses them more concisely.
Internet Access via Cable TV Network
Internet is a network of networks in which various computers connect each other through out the world. The connection to other computers is possible with the help of ISP (Internet Service Provider). Each Internet users depend dialup connections to connect to Internet. This has many disadvantages like very poor speed, may time cut downs etc. To solve the problem, Internet data can be transferred through Cable networks wired to the user computer. Different type connections used are PSTN connection, ISDN connection and Internet via Cable networks. Various advantages are High availability, High bandwidth to low cost, high speed data access, always on connectivity etc.The huge growth in the number of Internet users every year has resulted in the traffic congestion on the net, resulting in slower and expensive Internet access. As cable TV has a strong reach to homes, it is the best medium for providing the Internet to house - holds with faster access at feasible rates.
We are witnessing an unprecedented demand from residential and business customers, especially in the last few years, for access to the Internet, corporate intranets and various online information services. The Internet revolution is sweeping the country with a burgeoning number of the Internet users. As more and more people are being attracted towards the Internet, traffic congestion on the Net is continuously increasing due to limited bandwidths resulting in slower and expensive Internet access.
The number of household getting on the Internet has increased exponentially in the recent past. First time internet users are amazed at the internet's richness of content and personalization, never before offered by any other medium. But this initial awe last only till they experienced the slow speed of internet content deliver. Hence the popular reference "World Wide Wait"(not world wide web). There is a pent-up demand for the high-speed (or broad band) internet access for fast web browsing and more effective telecommuting.
India has a cable penetration of 80 million homes, offering a vast network for leveraging the internet access. Cable TV has a strong reach to the homes and therefore offering the Internet through cable could be a scope for furthering the growth of internet usage in the homes.
The cable is an alternative medium for delivering the Internet services in the US, there are already a million homes with cable modems, enabling the high-speed internet access over cable. In India, we are in the initial stages. We are experiencing innumerable local problems in Mumbai, Bangalore and Delhi, along with an acute shortage of international Internet connectivity.
Accessing the Internet on the public switched telephone networks (PSTN) still has a lot of problems. Such as drops outs. Its takes along time to download or upload large files. One has to pay both for the Internet connectivity as well as for telephone usages during that period. Since it is technically possible to offer higher bandwidth by their cable, home as well as corporate users may make like it. Many people cannot afford a PC At their premises. Hardware obsolescence in the main problem to the home user. Who cannot afford to upgrade his PC every year? Cable TV based ISP solution s offer an economic alternative.
We are witnessing an unprecedented demand from residential and business customers, especially in the last few years, for access to the Internet, corporate intranets and various online information services. The Internet revolution is sweeping the country with a burgeoning number of the Internet users. As more and more people are being attracted towards the Internet, traffic congestion on the Net is continuously increasing due to limited bandwidths resulting in slower and expensive Internet access.
The number of household getting on the Internet has increased exponentially in the recent past. First time internet users are amazed at the internet's richness of content and personalization, never before offered by any other medium. But this initial awe last only till they experienced the slow speed of internet content deliver. Hence the popular reference "World Wide Wait"(not world wide web). There is a pent-up demand for the high-speed (or broad band) internet access for fast web browsing and more effective telecommuting.
India has a cable penetration of 80 million homes, offering a vast network for leveraging the internet access. Cable TV has a strong reach to the homes and therefore offering the Internet through cable could be a scope for furthering the growth of internet usage in the homes.
The cable is an alternative medium for delivering the Internet services in the US, there are already a million homes with cable modems, enabling the high-speed internet access over cable. In India, we are in the initial stages. We are experiencing innumerable local problems in Mumbai, Bangalore and Delhi, along with an acute shortage of international Internet connectivity.
Accessing the Internet on the public switched telephone networks (PSTN) still has a lot of problems. Such as drops outs. Its takes along time to download or upload large files. One has to pay both for the Internet connectivity as well as for telephone usages during that period. Since it is technically possible to offer higher bandwidth by their cable, home as well as corporate users may make like it. Many people cannot afford a PC At their premises. Hardware obsolescence in the main problem to the home user. Who cannot afford to upgrade his PC every year? Cable TV based ISP solution s offer an economic alternative.
MPEG-7
As more and more audiovisual information becomes available from many sources around the world, many people would like to use this information for various purposes. This challenging situation led to the need for a solution that quickly and efficiently searches for and/or filters various types of multimedia material that's interesting to the user.For example, finding information by rich-spoken queries, hand-drawn images, and humming improves the user-friendliness of computer systems and finally addresses what most people have been expecting from computers. For professionals, a new generation of applications will enable high-quality information search and retrieval.
For example, TV program producers can search with "laser-like precision" for occurrences of famous events or references to certain people, stored in thousands of hours of audiovisual records, in order to collect material for a program. This will reduce program production time and increase the quality of its content.MPEG-7 is a multimedia content description standard, (to be defined by September 2001), that addresses how humans expect to interact with computer systems, since it develops rich descriptions that reflect those expectations.
The Moving Pictures Experts Group abbreviated MPEG is part of the International Standards Organization (ISO), and defines standards for digital video and digital audio. The primal task of this group was to develop a format to play back video and audio in real time from a CD. Meanwhile the demands have raised and beside the CD the DVD needs to be supported as well as transmission equipment like satellites and networks. All this operational uses are covered by a broad selection of standards. Well known are the standards MPEG-1, MPEG-2, MPEG-4 and MPEG-7.
Each standard provides levels and profiles to support special applications in an optimized way.It's clearly much more fun to develop multimedia content than to index it. The amount of multimedia content available -- in digital archives, on the World Wide Web, in broadcast data streams and in personal and professional databases -- is growing out of control. But this enthusiasm has led to increasing difficulties in accessing, identifying and managing such resources due to their volume and complexity and a lack of adequate indexing standards. The large number of recently funded DLI-2 projects related to the resource discovery of different media types, including music, speech, video and images, indicates an acknowledgement of this problem and the importance of this field of research for digital libraries.
For example, TV program producers can search with "laser-like precision" for occurrences of famous events or references to certain people, stored in thousands of hours of audiovisual records, in order to collect material for a program. This will reduce program production time and increase the quality of its content.MPEG-7 is a multimedia content description standard, (to be defined by September 2001), that addresses how humans expect to interact with computer systems, since it develops rich descriptions that reflect those expectations.
The Moving Pictures Experts Group abbreviated MPEG is part of the International Standards Organization (ISO), and defines standards for digital video and digital audio. The primal task of this group was to develop a format to play back video and audio in real time from a CD. Meanwhile the demands have raised and beside the CD the DVD needs to be supported as well as transmission equipment like satellites and networks. All this operational uses are covered by a broad selection of standards. Well known are the standards MPEG-1, MPEG-2, MPEG-4 and MPEG-7.
Each standard provides levels and profiles to support special applications in an optimized way.It's clearly much more fun to develop multimedia content than to index it. The amount of multimedia content available -- in digital archives, on the World Wide Web, in broadcast data streams and in personal and professional databases -- is growing out of control. But this enthusiasm has led to increasing difficulties in accessing, identifying and managing such resources due to their volume and complexity and a lack of adequate indexing standards. The large number of recently funded DLI-2 projects related to the resource discovery of different media types, including music, speech, video and images, indicates an acknowledgement of this problem and the importance of this field of research for digital libraries.
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