Definition
According to the dictionary guidance is the 'process of guiding the path of an object towards a given point, which in general may be moving'. The process of guidance is based on the position and velocity if the target relative to the guided object. The present day ballistic missiles are all guided using the global positioning system or GPS.GPS uses satellites as instruments for sending signals to the missile during flight and to guide it to the target.
SATRACK is a system that was developed to provide an evaluation methodology for the guidance system of the ballistic missiles. This was developed as a comprehensive test and evaluation program to validate the integrated weapons system design for nuclear powered submarines launched ballistic missiles.this is based on the tracking signals received at the missile from the GPS satellites. SATRACK has the ability to receive record, rebroadcast and track the satellite signals.
SATRACK facility also has the great advantage that the whole data obtained from the test flights can be used to obtain a guidance error model. The recorded data along with the simulation data from the models can produce a comprehensive guidance error model. This will result in the solution that is the best flight path for the missile.
The signals for the GPS satellite navigation are two L-band frequency signals. They can be called L1 and L2.L1 is at 1575.42 MHz and L2 at 1227.60 MHz.The modulations used for these GPS signals are
1. Narrow band clear/acquisition code with 2MHz bandwidth.
2. Wide band encrypted P code with 20MHz bandwidth.
L1 is modulated using the narrow band C/A code only. This signal will give an accuracy of close to a 100m only. L2 is modulated using the P code. This code gives a higher accuracy close to 10m that is why they are encrypted. The parameters that a GPS signal carries are latitude, longitude, altitude and time. The modulations applied to each frequency provide the basis for epoch measurements used to determine the distances to each satellite. Tracking of the dual frequency GPS signals provides a way to correct measurements from the effect of refraction through the ionosphere. An alternate frequency L3 at 1381.05MHz was also used to compensate for the ionospheric effects.
Definition
The World Wide Web's current implementation is designed predominantly for information retrieval and display in a human readable form. Its data formats and protocols are neither intended nor suitable for machine-to-machine interaction without humans in the loop. Emergent Internet uses - including peer- to- peer and grid computing - provide both a glimpse and impetus for evolving the Internet into a distributed computing platform.
What would be needed to make the Internet into a application-hosting platform. This would be a networked, distributed counterpart of the hosting environment that traditional operating system provides to application in a single node. Creating this platform requires additional functional layer to the Internet that can allocate and manage resources necessary for application execution.
Given such a hosting environment, software designers could create network application without having to know at design time the type or the number of nodes the application will execute on. With proper support, the system could allocate and bind software components to the resources they require at runtime, based on resource requirement, availability, connectivity and system state at actual time of execution. In contrast, early bindings tend to result in static allocations that cannot adapt well to resource, load and availability variations, thus the software components tend to be less efficient and have difficulty recovering from failures. The foundation of proposed approach is to disaggregate and virtualize.
System resources as services that can be described, discovered and dynamically configured at runtime to execute a application. Such a system can be built as a combination and extension of Web services, peer-to-peer computing, and grid computing standards and technologies, It thus follows the successful internet model of adding minimal and relatively simple functional layers to meet requirements while atop already available technologies.
But it does not advocate an "Internet OS" approach that would provide some form of uniform or centralized global-resources management. Several theoretical and practical reasons makes such an approach undesirable, including its inability to scale and the need to provide and manage supporting software on every participating platform. Instead, we advocate a mechanism that supports spontaneous, dynamic, and voluntary collaboration among entities with their contributing resources.
Definition
A correct firewall policy can minimize the exposure of many networks however they are quite useless against attacks launched from within. Hackers are also evolving their attacks and network subversion methods. These techniques include email based Trojan, stealth scanning techniques, malicious code and actual attacks, which bypass firewall policies by tunneling access over allowed protocols such as ICMP, HTTP, DNS, etc. Hackers are also very good at creating and releasing malware for the ever-growing list of application vulnerabilities to compromise the few services that are being let through by a firewall.
IDS arms your business against attacks by continuously monitoring network activity, ensuring all activity is normal. If IDS detects malicious activity it responds immediately by destroying the attacker's access and shutting down the attack. IDS reads network traffic and looks for patterns of attacks or signatures, if a signature is identified, IDS sends an alert to the Management Console and a response is immediately deployed.
What is intrusion?
An intrusion is somebody attempting to break into or misuse your system. The word "misuse" is broad, and can reflect something severe as stealing confidential data to something minor such as misusing your email system for Spam.
What is an IDS?
An IDS is the real-time monitoring of network/system activity and the analysing of data for potential vulnerabilities and attacks in progress.
Need For IDS
Who are attacked?
Internet Information Services (IIS) web servers - which host web pages and serve them to users - are highly popular among business organizations, with over 6 million such servers installed worldwide. Unfortunately, IIS web servers are also popular among hackers and malicious fame-seekers - as a prime target for attacks!
As a result, every so often, new exploits emerge which endanger your IIS web server's integrity and stability. Many administrators have a hard time keeping up with the various security patches released for IIS to cope with each new exploit, making it easy for malicious users to find a vulnerable web server on the Internet. There are multiple issues which can completely endanger your Web server - and possibly your entire corporate network and reputation.
People fell there is nothing on their system that anybody would want. But what they are unaware of is that, there is the issue of legal liability. You are potentially liable for damages caused by a hacker using your machine. You must be able to prove to a court that you took "reasonable" measures to defend yourself from hackers. For example, consider if you put a machine on a fast link (cable modem or DSL) and left administrator/root accounts open with no password. Then if a hacker breaks into that machine, then uses that machine to break into a bank, you may be held liable because you did not take the most obvious measures in securing the machine.
