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Download Full Article WAP

WAP: An Introduction                                                           

The Wireless Application Protocol (WAP) is a new advanced intelligent messaging service for digital mobile phones and other mobile terminals that will allow you to see Internet content in special text format on special WAP-enabled mobile phones. Enabling information access from handheld devices requires a deep understanding of both technical and market issues that are unique to the wireless environment. The WAP specification was developed by the industry’s best minds to address these issues. Wireless devices represent the ultimate constrained computing device with limited CPU, memory and battery life and a simple user interface. Wireless networks are constrained by low bandwidth, high latency and unpredictable availability and stability. The WAP specification addresses these issues by using the best of existing standards and developing new extensions when needed. The WAP solution leverages the tremendous investment in web servers, web development tools, web programmers and web applications while solving the unique problems associated with the wireless domain. The specification ensures that this solution is fast, reliable and secure. The WAP specification is developed and supported by the wireless telecommunication community so that the entire industry and its subscribers can benefit from a single, open specification. 

 The WAP forum                        

The WAP specification was developed by the WAP forum, a consortium founded by the telecommunication giants Nokia, Ericsson, Phone.com and Motorola. The WAP forum’s membership roster now includes computer industry heavyweights such as Microsoft, Oracle, IBM and Intel along with several hundred other companies. The WAP forum is an industry group dedicated to the goal of enabling sophisticated telephony and information services on handheld wireless devices. The WAP forum has drafted a global wireless protocol specification for all wireless networks and is contributing it to various industry groups and standard bodies.  This WAP specification by the WAP forum enables manufacturers, network operators, content providers and application developers to offer compatible products and secure services on all devices and networks, resulting in greater economies of scale and universal access to information.   

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Download Full Article 3g

Marconi’s innovative perception of electromagnetic waves and the air interface in 1897 was the first milestone on the important road to shared use of the radio spectrum. But only after almost a century later did mobile wireless communication start to take off. Despite a series of disappointing false starts, communication world in the late 1980’s was rapidly becoming more mobile for a much wider segment of communication users than ever before. With the advent of wireless technology, a transition from point-to-point communication toward person to-person communication (i.e.; independent of position) has begun. Testimony to this is the rapidly increasing penetration of cellular phones all across the world. In anticipation of the growing consumer demands, the next generation of wireless systems endeavors to provide person-to-person communication of the circuit and packet multimedia data.

The first generation cellular networks, which were based on analog technology with FM modulation, have been successfully deployed since the early and mid 1980’s. A typical example of a first generation cellular telephone system ( 1G ) is the Advanced Mobile Phone Services ( AMPS) . Second generation ( 2G ) wireless systems employ digital modulation and advanced call-processing capabilities. In view of the processing complexity required for these digital systems, two offered advantages are the possibility of using spectrally efficient radio transmission schemes such as Time Division Multiple Access ( TDMA ) or Code Division Multiple Access ( CDMA ), in comparison to the analog Frequency Division Multiple Access ( FDMA ) schemes previously employed and the provision for implementation of a wide variety of integrated speech and data services such as paging and low data rate network access. Examples of 2 G  wireless systems include the Global System for Mobile communication ( GSM ), TDMA IS-54/IS-136 and Personal Digital Cellular ( PDC ).

Third Generation ( 3G ) wireless systems will evolve from mature 2G networks with the aim of providing universal access and global roaming. More important these systems are expected to support multi dimensional (multi-information media, multi-transmission media, and multi-layered networks) high-speed wireless communication- an important milestone toward achieving the grand vision of ubiquitous personal communications. Introduction of wide band packet-data services for wireless Internet up to 2Mbps will be the main attribute of 3G system.

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Download Full Article Intrusion Detection

In the last three years, the networking revolution has finally come of age. More than ever before, we see that the Internet is changing computing as we know it. The possibilities and opportunities are limitless; unfortunately, so too are the risks and chances of malicious intrusions.

It is very important that the security mechanisms of a system are designed so as to prevent unauthorized access to system resources and data. However, completely preventing breaches of security appear, at present, unrealistic. We can, however, try to detect these intrusion attempts so that action may be taken to repair the damage later. This field of research is called Intrusion Detection.

Anderson, while introducing the concept of intrusion detection in 1980, defined an intrusion attempt or a threat to be the potential possibility of a deliberate unauthorized attempt to

• access information,
• manipulate information, or
• render a system unreliable or unusable.

Since then, several techniques for detecting intrusions have been studied. This paper discusses why intrusion detection systems are needed, the main techniques, present research in the field, and possible future directions of research.

SECURITY POLICY

A Security Policy defines what is permitted and what is denied on a system. There are two basic philosophies behind any security policy:

1. Prohibitive where everything that is not expressly permitted is denied.
2. Permissive where everything that is not expressly denied is permitted.

Elements of a System’s Security

A computer system can be considered as a set of resources which are available for use by authorized users. A paper by Donn P outlines six elements of security that must be addressed by a security administrator. It is worth evaluting any tool by determining how it address these six elements.

1. Availability – the system must be available for use when the users need it. Similarly, critical data must be available at all times.
2. Utility – the system, and data on the system, must be useful for a purpose.
3. Integrity – the system and its data must be complete, whole, and in a readable condition.
4. Authenticity – the system must be able to verify the identity of users, and the users should be able to verify the identity of the system.
5. Confidentiality – private data should be known only to the owner of the data, or to a chosen chosen few with whom the owner shares the data.
6. Possession – the owners of the system must be able to control it. Losing control of a system to a malicious user affects the security of the system for all other users.

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Download Full Article HAAPS

Affordable bandwidth will be as essential to the Information Revolution in the21 st century as inexpensive power was to the Industrial Revolution in the 18 th and 19 th centuries. Today’s global communications infrastructures of landlines, cellular towers, and satellites are inadequately equipped to support the increasing worldwide demand for faster, better, and less expensive service. At a time when conventional ground and satellite systems are facing increasing obstacles and spiraling costs, a low cost solution is being advocated.

This paper focuses on airborne platforms- airships, planes, helicopters or some hybrid solutions which could operate at stratospheric altitudes for significant periods of time, be low cost and be capable of carrying sizable multipurpose communications payloads. This report briefly presents an overview about the internal architecture of a High Altitude Aeronautical Platform and the various HAAPS projects.

HAAPS

 High Altitude Aeronautical Platform Stations (HAAPS) is the name of a technology for providing wireless narrowband and broadband telecommunication services as well as broadcasting services with either airships or aircrafts. The HAAPS are operating at altitudes between 3 to 22 km. A HAPS shall be able to cover a service area of up to 1′000 km diameter, depending on the minimum elevation angle accepted from the user’s location. The platforms may be airplanes or airships (essentially balloons) and may be manned or un-manned with autonomous operation coupled with remote control from the ground. While the term HAP may not have a rigid definition, we take it to mean a solar-powered and unmanned airplane or airship, capable of long endurance on-station –possibly several years.

Various types of platform options exist: SkyStation™, the Japanese Stratospheric Platform Project, the European Space Agency (ESA) and others suggest the use of airships/blimps/dirigibles. These will be stationed at 21km and are expected to remain aloft for about 5 years. Angel Technologies (HALO™), AeroVironment/ NASA (Helios) and the European Union (Heliplat) propose the use of high altitude long endurance aircraft. The aircraft are either engine or solar powered and are stationed at 16km (HALO) or 21km (Helios). Helios is expected to stay aloft for a minimum of 6 months whereas HALO will have 3 aircraft flying in 8- hour shifts. Platforms Wireless International is implementing a tethered aerostat situated at ~6km.

A high altitude telecommunication system comprises an airborne platform – typically at high atmospheric or stratospheric altitudes – with a telecommunications payload, and associated ground station telecommunications equipment. The combination of altitude, payload capability, and power supply capability makes it ideal to serve new and metropolitan areas with advanced telecommunications services such as broadband access and regional broadcasting. The opportunities for applications are virtually unlimited. The possibilities range from narrowband services such as paging and mobile voice to interactive broadband services such as multimedia and video conferencing. For future telecommunications operators such a platform could provide blanket coverage from day one with the added advantage of not being limited to a single service. Where little or unreliable infrastructure exists, traffic could be switched through air via the HAPS platform. Technically, the concept offers a solution to the propagation and rollout problems of terrestrial infrastructure and capacity and cost problems of satellite networks. Recent developments in digital array antenna technology make it possible to construct 100+ cells from one platform. Linking and switching of traffic between multiple high altitude platforms, satellite networks and terrestrial gateways are also possible. Economically it provides the opportunity for developing countries to have satellite-like infrastructure without the funds flowing out of the country due to gateways and control stations located outside of these countries.

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Download Full Article Augmented reality (AR)

Augmented reality (AR) refers to computer displays that add virtual information to a user’s sensory perceptions. Most AR research focuses on see-through devices, usually worn on the head that overlay graphics and text on the user’s view of his or her surroundings. In general it superimposes graphics over a real world environment in real time.

                Getting the right information at the right time and the right place is key in all these applications. Personal digital assistants such as the Palm and the Pocket PC can provide timely information using wireless networking and Global Positioning System (GPS) receivers that constantly track the handheld devices. But what makes augmented reality different is how the information is presented: not on a separate display but integrated with the user’s perceptions. This kind of interface minimizes the extra mental effort that a user has to expend when switching his or her attention back and forth between real-world tasks and a computer screen. In augmented reality, the user’s view of the world and the computer interface literally become one.

Between the extremes of real life and Virtual Reality lies the spectrum of Mixed Reality, in which views of the real world are combined in some proportion with views of a virtual environment. Combining direct view, stereoscopic video, and stereoscopic graphics, Augmented Reality describes that class of displays that consists primarily of a real environment, with graphic enhancements or augmentations.

                In Augmented Virtuality, real objects are added to a virtual environment. In Augmented reality, virtual objects are added to real world. 

                An AR system supplements the real world with virtual (computer generated) objects that appear to co-exist in the same space as the real world. Virtual Reality is a synthetic environment

1.1 Comparison between AR and virtual environments

                                The overall requirements of AR can be summarized by comparing them against the requirements for Virtual Environments, for the three basic subsystems that they require.

1) Scene generator: Rendering is not currently one of the major problems in AR. VE systems have much higher requirements for realistic images because they completely replace the real world with the virtual environment. In AR, the virtual images only supplement the real world. Therefore, fewer virtual objects need to be drawn, and they do not necessarily have to be realistically rendered in order to serve the purposes of the application.

2) Display device: The display devices used in AR may have less stringent requirements than VE systems demand, again because AR does not replace the real world. For example, monochrome displays may be adequate for some AR applications, while virtually all VE systems today use full color. Optical see-through HMDs with a small field-of-view may be satisfactory because the user can still see the real world with his peripheral vision; the see-through HMD does not shut off the user’s normal field-of-view. Furthermore, the resolution of the monitor in an optical see-through HMD might be lower than what a user would tolerate in a VE application, since the optical see-through HMD does not reduce the resolution of the real environment.

3) Tracking and sensing: While in the previous two cases AR had lower requirements than VE, that is not the case for tracking and sensing. In this area, the requirements for AR are much stricter than those for VE systems. A major reason for this is the registration problem.

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