GOOGLE SELF DRIVING CAR

Jaywalking pedestrians. Cars lurching out of hidden driveways. Double-parked delivery trucks blocking your lane and your view. At a busy time of day, a typical city street can leave even experienced drivers sweaty-palmed and irritable. We all dream of a world in which city centers are freed of congestion from cars circling for parking (PDF) and have fewer intersections made dangerous by distracted drivers. That’s why over the last year we’ve shifted the focus of the Google self-driving car project onto mastering city street driving.

Since our last update, we’ve logged thousands of miles on the streets of our hometown of Mountain View, Calif. A mile of city driving is much more complex than a mile of freeway driving, with hundreds of different objects moving according to different rules of the road in a small area. We’ve improved our software so it can detect hundreds of distinct objects simultaneously—pedestrians, buses, a stop sign held up by a crossing guard, or a cyclist making gestures that indicate a possible turn. A self-driving vehicle can pay attention to all of these things in a way that a human physically can’t—and it never gets tired or distracted.

Click the LINK showing how this vehicle navigates some common scenarios near the Googleplex: 

As it turns out, what looks chaotic and random on a city street to the human eye is actually fairly predictable to a computer. As we’ve encountered thousands of different situations, we’ve built software models of what to expect, from the likely (a car stopping at a red light) to the unlikely (blowing through it). We still have lots of problems to solve, including teaching the car to drive more streets in Mountain View before we tackle another town, but thousands of situations on city streets that would have stumped us two years ago can now be navigated autonomously.

Our vehicles have now logged nearly 700,000 autonomous miles, and with every passing mile we’re growing more optimistic that we’re heading toward an achievable goal—a vehicle that operates fully without human intervention. 

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WHAT IS FIBER OPTICS AND HOW DOES IT WORK

Fiber-optic lines have revolutionized long-distance phone calls, cable TV and the Internet. See more electronic parts pictures.

Introduction to How Fiber Optics Work

You hear about fiber-optic cables whenever people talk about the telephone system, the cable TV system or the Internet. Fiber-optic lines are strands of optically pure glass as thin as a human hair that carry digital information over long distances. They are also used in medical imaging and mechanical engineering inspection.

In this article, we will show you how these tiny strands of glass transmit light and the fascinating way that these strands are made.

What are Fiber Optics?

Fiber optics (optical fibers) are long, thin strands of very pure glass about the diameter of a human hair. They are arranged in bundles called optical cables and used to transmit light signals over long distances.

If you look closely at a single optical fiber, you will see that it has the following parts:

·         Core - Thin glass center of the fiber where the light travels

·         Cladding - Outer optical material surrounding the core that reflects the light back into the core

·         Buffer coating - Plastic coating that protects the fiber from damage and moisture

Hundreds or thousands of these optical fibers are arranged in bundles in optical cables. The bundles are protected by the cable's outer covering, called a jacket.

Optical fibers come in two types:

·         Single-mode fibers

·         Multi-mode fibers

See Tpub.com: Mode Theory for a good explanation.

Single-mode fibers have small cores (about 3.5 x 10^-4 inches or 9 microns in diameter) and transmit infrared laser light (wavelength = 1,300 to 1,550 nanometers).Multi-mode fibers have larger cores (about 2.5 x 10^-3 inches or 62.5 microns in diameter) and transmit infrared light (wavelength = 850 to 1,300 nm) from light-emitting diodes (LEDs).

Some optical fibers can be made from plastic. These fibers have a large core (0.04 inches or 1 mm diameter) and transmit visible red light (wavelength = 650 nm) from LEDs.

Let's look at how an optical fiber works.

  Diagram of total internal reflection in an optical fiber

How Does an Optical Fiber Transmit Light?

Suppose you want to shine a flashlight beam down a long, straight hallway. Just point the beam straight down the hallway -- light travels in straight lines, so it is no problem. What if the hallway has a bend in it? You could place a mirror at the bend to reflect the light beam around the corner. What if the hallway is very winding with multiple bends? You might line the walls with mirrors and angle the beam so that it bounces from side-to-side all along the hallway. This is exactly what happens in an optical fiber.

The light in a fiber-optic cable travels through the core (hallway) by constantly bouncing from the cladding (mirror-lined walls), a principle called total internal reflection. Because the cladding does not absorb any light from the core, the light wave can travel great distances.

However, some of the light signal degrades within the fiber, mostly due to impurities in the glass. The extent that the signal degrades depends on the purity of the glass and the wavelength of the transmitted light (for example, 850 nm = 60 to 75 percent/km; 1,300 nm = 50 to 60 percent/km; 1,550 nm is greater than 50 percent/km). Some premium optical fibers show much less signal degradation -- less than 10 percent/km at 1,550 nm.

A Fiber-Optic Relay System

To understand how optical fibers are used in communications systems, let's look at an example from a World War II movie or documentary where two naval ships in a fleet need to communicate with each other while maintaining radio silence or on stormy seas. One ship pulls up alongside the other. The captain of one ship sends a message to a sailor on deck. The sailor translates the message into Morse code (dots and dashes) and uses a signal light (floodlight with a venetian blind type shutter on it) to send the message to the other ship. A sailor on the deck of the other ship sees the Morse code message, decodes it into English and sends the message up to the captain.

Now, imagine doing this when the ships are on either side of the ocean separated by thousands of miles and you have a fiber-optic communication system in place between the two ships. Fiber-optic relay systems consist of the following:

·         Transmitter - Produces and encodes the light signals

·         Optical fiber - Conducts the light signals over a distance

·         Optical regenerator - May be necessary to boost the light signal (for long distances)

·         Optical receiver - Receives and decodes the light signals

Transmitter

The transmitter is like the sailor on the deck of the sending ship. It receives and directs the optical device to turn the light "on" and "off" in the correct sequence, thereby generating a light signal.

The transmitter is physically close to the optical fiber and may even have a lens to focus the light into the fiber. Lasers have more power than LEDs, but vary more with changes in temperature and are more expensive. The most common wavelengths of light signals are 850 nm, 1,300 nm, and 1,550 nm (infrared, non-visible portions of the spectrum).

Optical Regenerator

As mentioned above, some signal loss occurs when the light is transmitted through the fiber, especially over long distances (more than a half mile, or about 1 km) such as with undersea cables. Therefore, one or more optical regenerators is spliced along the cable to boost the degraded light signals.

An optical regenerator consists of optical fibers with a special coating (doping). The doped portion is "pumped" with a laser. When the degraded signal comes into the doped coating, the energy from the laser allows the doped molecules to become lasers themselves. The doped molecules then emit a new, stronger light signal with the same characteristics as the incoming weak light signal. Basically, the regenerator is a laser amplifier for the incoming signal.

Optical Receiver

The optical receiver is like the sailor on the deck of the receiving ship. It takes the incoming digital light signals, decodes them and sends the electrical signal to the other user's computer, TV or telephone (receiving ship's captain). The receiver uses a photocell or photodiode to detect the light.

Advantages of Fiber Optics

Why are fiber-optic systems revolutionizing telecommunications? Compared to conventional metal wire (copper wire), optical fibers are:

Less expensive - Several miles of optical cable can be made cheaper than equivalent lengths of copper wire. This saves your provider (cable TV, Internet) and you money. Thinner - Optical fibers can be drawn to smaller diameters than copper wire. Higher carrying capacity - Because optical fibers are thinner than copper wires, more fibers can be bundled into a given-diameter cable than copper wires. This allows more phone lines to go over the same cable or more channels to come through the cable into your cable TV box. Less signal degradation - The loss of signal in optical fiber is less than in copper wire. Light signals - Unlike electrical signals in copper wires, light signals from one fiber do not interfere with those of other fibers in the same cable. This means clearer phone conversations or TV reception. Low power - Because signals in optical fibers degrade less, lower-power transmitters can be used instead of the high-voltage electrical transmitters needed for copper wires. Again, this saves your provider and you money. Digital signals - Optical fibers are ideally suited for carrying digital information, which is especially useful in computer networks. Non-flammable - Because no electricity is passed through optical fibers, there is no fire hazard. Lightweight - An optical cable weighs less than a comparable copper wire cable. Fiber-optic cables take up less space in the ground. Flexible - Because fiber optics are so flexible and can transmit and receive light, they are used in many flexible digital cameras for the following purposes:

·         Medical imaging - in bronchoscopes, endoscopes, laparoscopes

·         Mechanical imaging - inspecting mechanical welds in pipes and engines (in airplanes, rockets, space shuttles, cars)

·         Plumbing - to inspect sewer lines

Because of these advantages, you see fiber optics in many industries, most notably telecommunications and computer networks. For example, if you telephone Europe from the United States (or vice versa) and the signal is bounced off a communications satellite, you often hear an echo on the line. But with transatlantic fiber-optic cables, you have a direct connection with no echoes.

MCVD process for making the preform blank

Image courtesy Fibercore Ltd.

How Are Optical Fibers Made?

Now that we know how fiber-optic systems work and why they are useful -- how do they make them? Optical fibers are made of extremely pure optical glass. We think of a glass window as transparent, but the thicker the glass gets, the less transparent it becomes due to impurities in the glass. However, the glass in an optical fiber has far fewer impurities than window-pane glass. One company's description of the quality of glass is as follows: If you were on top of an ocean that is miles of solid core optical fiber glass, you could see the bottom clearly.

Making optical fibers requires the following steps:

1.     Making a preform glass cylinder

2.     Drawing the fibers from the preform

3.     Testing the fibers

Making the Preform Blank

The glass for the preform is made by a process called modified chemical vapor deposition(MCVD).

In MCVD, oxygen is bubbled through solutions of silicon chloride (SiCl4), germanium chloride (GeCl4) and/or other chemicals. The precise mixture governs the various physical and optical properties (index of refraction, coefficient of expansion, melting point, etc.). The gas vapors are then conducted to the inside of a synthetic silicaor quartz tube (cladding) in a special lathe. As the lathe turns, a torch is moved up and down the outside of the tube. The extreme heat from the torch causes two things to happen:

Lathe used in preparing the preform blank Photo courtesy Fiber core Ltd.

·         The silicon and germanium react with oxygen, forming silicon dioxide (SiO2) and germanium dioxide (GeO2).

·         The silicon dioxide and germanium dioxide deposit on the inside of the tube and fuse together to form glass.

The lathe turns continuously to make an even coating and consistent blank. The purity of the glass is maintained by using corrosion-resistant plastic in the gas delivery system (valve blocks, pipes, seals) and by precisely controlling the flow and composition of the mixture. The process of making the preform blank is highly automated and takes several hours. After the preform blank cools, it is tested for quality control (index of refraction).

Drawing Fibers from the Preform Blank

Once the preform blank has been tested, it gets loaded into a fiber drawing tower.

Diagram of a fiber drawing tower used to draw optical glass fibers from a preform blank

The blank gets lowered into a graphite furnace (3,452 to 3,992 degrees Fahrenheit or 1,900 to 2,200 degrees Celsius) and the tip gets melted until a molten glob falls down by gravity. As it drops, it cools and forms a thread.

 The operator threads the strand through a series of coating cups (buffer coatings) and ultraviolet light curing ovens onto a tractor-controlled spool. The tractor mechanism slowly pulls the fiber from the heated preform blank and is precisely controlled by using a laser micrometer to measure the diameter of the fiber and feed the information back to the tractor mechanism. Fibers are pulled from the blank at a rate of 33 to 66 ft/s (10 to 20 m/s) and the finished product is wound onto the spool. It is not uncommon for spools to contain more than 1.4 miles (2.2 km) of optical fiber.

Testing the Finished Optical Fiber

The finished optical fiber is tested for the following:

 

Finished spool of optical fiber

Photo courtesy Corning

·         Tensile strength - Must withstand 100,000 lb/in² or more

·         Refractive index profile - Determine numerical aperture as well as screen for optical defects

·         Fiber geometry - Core diameter, cladding dimensions and coating diameter are uniform

·         Attenuation - Determine the extent that light signals of various wavelengths degrade over distance

·         Information carrying capacity (bandwidth) - Number of signals that can be carried at one time (multi-mode fibers)

·         Chromatic dispersion - Spread of various wavelengths of light through the core (important for bandwidth)

·         Operating temperature/humidity range

·         Temperature dependence of attenuation

·         Ability to conduct light underwater - Important for undersea cables

Once t­he fibers have passed the quality control, they are sold to telephone companies, cable companies and network providers. Many companies are currently replacing their old copper-wire-based systems with new fiber-optic-based systems to improve speed, capacity and clarity.

Total internal reflection in an optical fiber

Physics of Total Internal Reflection

When light passes from a medium with one index of refraction (m1) to another medium with a lower index of refraction (m2), it bends or refracts away from an imaginary line perpendicular to the surface (normal line). As the angle of the beam through m1 becomes greater with respect to the normal line, the refracted light through m2 bends further away from the line.

At one particular angle (critical angle), the refracted light will not go into m2, but instead will travel along the surface between the two media (sine [critical angle] = n2/n1 where n1 and n2 are the indices of refraction [n1 is greater than n2]). If the beam through m1 is greater than the critical angle, then the refracted beam will be reflected entirely back into m1 (total internal reflection), even though m2 may be transparent!

In physics, the critical angle is described with respect to the normal line. In fiber optics, the critical angle is described with respect to the parallel axis running down the middle of the fiber. Therefore, the fiber-optic critical angle = (90 degrees - physics critical angle).

In an optical fiber, the light travels through the core (m1, high index of refraction) by constantly reflecting from the cladding (m2, lower index of refraction) because the angle of the light is always greater than the critical angle. Light reflects from the cladding no matter what angle the fiber itself gets bent at, even if it's a full circle!

Because the cladding does not absorb any light from the core, the light wave can travel great distances. However, some of the light signal degrades within the fiber, mostly due to impurities in the glass. The extent that the signal degrades depends upon the purity of the glass and the wavelength of the transmitted light (for example, 850 nm = 60 to 75 percent/km; 1,300 nm = 50 to 60 percent/km; 1,550 nm is greater than 50 percent/km). Some premium optical fibers show much less signal degradation -- less than 10 percent/km at 1,550 nm.

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6 MOST COMMON PASSWORD CRACKING METHODS AND THEIR COUNTERMEASURES

There are number of methods out their used by hackers to hack your account or get your personal information. Today in this post i will share with you guys 6 Most commonly used method to crack password and their countermeasures. You must check out this article to be safe and to prevent your online accounts from hacking.

1. BruteForce Attack

Any password can be cracked using Brute-force attack. Brute-force attacks try every possible combinations of numbers, letters and special characters until the right password is match. Brute-force attacks can take very long time depending upon the complexity of the password. The cracking time is determined by the speed of computerand complexity of the password.

Countermeasure: Use long and complex passwords. Try to use combination of upper and lowercase letters along with numbers. Brute-force attack will take hundreds or even thousands of years to crack such complex and long passwords.

Example: Passwords like "iloveu" or "password" can be cracked easily whereas computer will take years to crack passwords like "aN34lL00"

2. Social Engineering

Social engineering is process of manipulating someone to trust you and get information from them. For example, if the hacker was trying to get the password of a co-workers or friends computer, he could call him pretending to be from the IT department and simply ask for his login details. Sometime hackers call the victim pretending to be from bank and ask for their credit cards details. Social Engineering can be used to get someone password, to get bank credentials or any personal information.

Countermeasure: If someone tries to get your personal or bank details ask them few questions. Make sure the person calling you is legit. Never ever give your credit card details on phone.

3. Rats And Keyloggers

In keylogging or RATing the hacker sends keylogger or rat to the victim. This allows hacker to monitor every thing victim do on his computer. Every keystroke is logged including passwords. Moreever hacker can even control the victims computer.

Countermeasure: Never login to your bank account from cyber cafe or someone elsecomputer. If its important use on-screen or virtual keyboard while tying the login. Use latest anti-virus software and keep them updated. 

4. Phishing

Phishing is the most easiest and popular hacking method used by hackers to get someone account details. In Phishing attack hacker send fake page of real website like facebook, gmail to victim. When someone login through that fake page his details is send to the hacker. This fake pages can be easily created and hosted on free web-hosting sites.

Countermeasure: Phishing attacks are very easy to avoid. The url of this phishing pages are different from the real one. For example URL of phishing page of facebook might look like facbbook.com (As you can see There are two "b"). Always make sure that websites url is correct. 

5. Rainbow Table

A Rainbow table is a huge pre-computed list of hashes for every possible combination of characters. A password hash is a password that has gone through a mathematical algorithm such as md5 and is transformed into something which is not recognizable. A hash is a one way encryption so once a password is hashed there is no way to get the original string from the hashed string. A very commonly used hashing algorithm to store passwords in website databases is MD5. It is almost similar to dictionary attack, the only difference is, in rainbow tables attack hashed characters are used as passwords whereas in dictionary attack normal characters are used as passwords. 

Example: ‘hello’ in md5 is 5d41402abc4b2a76b9719d911017c592 and zero length string ("") is d41d8cd98f00b204e9800998ecf8427e

Countermeasure: Make sure you choose password that is long and complex. Creating tables for long and complex password takes a very long time and a lot of resources

6. Guessing

This seems silly but this can easily help you to get someones password within seconds. If hacker knows you, he can use information he knows about you to guess your password. Hacker can also use combination of Social Engineering and Guessing to acquire your password.

Countermeasure: Don't use your name, surname, phone number or birthdate as your password. Try to avoid creating password that relates to you. Create complex and long password with combination of letters and numbers.

CREDIT FROM COOL HACKING TRICK.

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WHAT IS KEYLOGGER AND HOW TO BE SAFEF ROM KEYLOGGERS

this tutorial will talk about the most use piece of software besides from RAT by hackers to observe your activities on your computer and that is keyloggers. A keylogger is a software or hardware device which monitors each and every key typed by you on your keyboard. I am going to talk about different types of keylogger and how to be safe from keyloggers. So lets learn somthing about keyloggers.

 1. What is keylogger ?

You might have heard about keyloggers but really dont know what they are reading this article will clear your mind. A keylogger also know as keystroke logger is software or hardware device which monitors each and every key typed by you on your keyboard. You can not identify the presence of keylogger on your computer since it runs in background and also it is not listed in task manager or control panel. It can be used by parents to keep eye on their childrens or company owner to spy on their employes.

2. How it can harm you ?

In this section i will talk about how keylogger can harm you in different ways for example It can be used by your enemy or friend to get sensitive information such as your username and password, Bank credit card details, or any other activities you do on your computer.

• Example: You login in to your Facebook account from a computer in which keylogger is install then your username and password will be captured.

3. Types of  keyloggers 

There are two types of keylogger hardware keylogger and software keylogger. Software keylogger is install in your computer where as a Hardware keylogger is attached to your keyboard. Looking at below images will clear your mind.

                              HARDWARE KEYLOGGER                                  

 

 SOFTWARE KEYLOGGER

 

                            

 4. How to Protect yourself from keyloggers ?

Keylogger  can be used by your enemy  to get sensitive information such as your Bank credit card details, or password of any social networking sites etc. In order to be safe keep following points in your mind.

• Never use your online banking from cyber cafe. If you want to use then you can try this method. open notepad and type anything Then copy and paste each word that comes in your username or password.
• You can even use above method to protect your facebook profile, yahoo or gmail id.
• When you enter cyber cafe make sure that no hardware device is attached to keyboard wire. Its look something similar to above image.

FROM CHT

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3 BASIC TIPS TO PREVENT A DDOS ATTACK

Distributed denial-of-service (DDoS) attacks are always in top headlines worldwide, as they are plaguing websites in banks, and virtually of almost every organization having a prominent online presence. The main cause behind the proliferation of DDoS attacks is that there is a very low-cost that the attacker has to incur to put such attack in motion. Fortunately, today various prevention methods have been developed to tackle such attacks. Before delving further into understanding about the ways to prevent DDoS attack, let’s first understand what exactly a DDoS attack is!

Understanding DDOS Attack

A DDoS (distributed denial-of-service) attack is an attempt made by attackers to make computers’ resources inaccessible to its anticipated user. In order to carry out a DDOS attack the attackers never uses their own system; rather they create a network of zombie computers often called as a “Botnet” – that is a hive of computers, to incapacitate a website or a web server.

Let’s understand the basic idea! Now, the attacker notifies all the computers present on the botnet to keep in touch with a particular site or a web server, time and again. This increases traffic on the network that causes in slowing down the speed of a site for the intended users. Unfortunately, at times the traffic can be really high that could even lead to shutting a site completely.

3 Basic Tips to Prevent a DDoS Attack

There are several ways to prevent the DDOS attack; however, here in this guest post I’ll be covering three basic tips that will help you to protect your website from the DDoS attack.

1. Buy More Bandwidth.

One of the easiest methods is to ensure that you have sufficient bandwidth on your web. You’ll be able to tackle lots of low-scale DDOS attacks simply by buying more bandwidth so as to service the requests. How does it help? Well, distributed denial of service is a nothing more than a game of capacity. Let’s suppose you have 10,000 computer systems each distributing 1 Mbps directed towards your way. This means you’re getting 10 GB of data that is hitting your web server every second. Now, that’s causes a lot of traffic!

So to avoid such issue, you need to apply the same rule intended for normal redundancy. According to this technique, if you wish to have more web servers just multiply around diverse data centers and next make use of load balancing. By spreading your traffic to various servers will help you balance the load and will most likely create large space adequate to handle the incessant increase in traffic.

However, there’s a problem with this method that is buying more bandwidth can be a costly affair. And as you’ll know that the current DDoS attacks are getting large, and can be a lot bigger exceeding your budget limit.

2. Opt for DDoS Mitigation Services.

A lot of network or Internet-service providers render DDoS mitigation capabilities. Look for an internet service provider having the largest DDoS protection and mitigation network, automated tools, and a pool of talented anti-DDoS technicians with the wherewithal to take action in real-time as per the varying DDoS attack characteristics. A viable alternative is to utilize a DDoS prevention appliance, which is specifically intended to discover and prevent distributed denial-of-service attacks.

3. Restricted Connectivity.

In case you have computer systems that are connected to the web directly, a better idea is to properly install/configure your routers and firewall so as to limit the connectivity. For an instance, while receiving some data from a client machine you can only allow traffic to pass from the machine only on a few chosen ports (like HTTP, POP, SMTP etc.) via the firewall.

Wrapping Up!

Websites are largely getting attacked by hackers every second. Denial-of-service attack is insanely getting huge and is creating a lot of problems for business organizations having strong online vicinity. In this guest post you’ll not only understand what a DDoS attack actually means, but will also come to know about a few type of methods to prevent DDoS attacks. Aforementioned are three tips that I’ll recommend you to run through to at least understand where to get started towards building a resilient web network with chances of surviving a DDoS attack.

FROM COOL HACKING TRICK

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