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|Computer keyboard is an device used to convert the keystrokes in to the electrical signals that a computer can understand. There are special types of switches and circuits to do this. When we press a key, it completes its corresponding circuit and an electrical signal goes to keyboard’s internal processor which detects the key which is pressed.
Keyboard contains its own internal processor that takes electrical signals through key strokes.
Every invention has a story which sizzles right behind the scenes. Ball Pen is also one invention, which though is of huge importance, yet not many know where it originated from. The history can be traced back to 1880s, when the first patent on a ball pen was issued to John Loud. This leather tanner attempted to make a writing object with which he could write on the leather he tanned. The pen, he had invented, constituted of a rotating steel ball as the tip held in a socket. It could write on the leather as intended by Loud. However, the invention proved futile for others as it proved way too coarse and messy for letter writing; so was disapproved commercially. The original patent lapsed with the failure of this invention on the grounds of practicality and usability.
The second innings for the ball pen was in the making and it all began again with the first and very famous stylized fountain pen. Invented by Cross, the fountain pen is identified as daddy to the ball pens. This invention triggered more of brainstorming that lasted till ball pen was born. Laszlo Jozsef Biro, a native of Budapest owns the patent of the ball pen to his name. What he had invented was a ball pen that contained ink cartridge in the pressurized form. A journalist named Biro took no time in noticing the quick drying capability of the ink used in the newspapers, and thought that if the same ink was utilized in a pen that smudged letters problem could be resolved. Being a proof reader, Biro had to refill his fountain pen from an ink bottle incessantly and this drove him crazy at times.
|In this tutorial, we will be covering how to use Classes and Objets instead of Parallel Arrays. In order to teach
students how to use arrays, many instructors give assignmentsallows students to gain confidence
when using arrays, this type of approach becomes very cumbersome to use and difficult to manage, especially as the number of elements stored increases in size and more so as the use of resizable collections like ArrayLists come into play.
So let's go ahead and start out with a standard inventory program that uses parallel arrays to store price, quantity and name. This program will display a menu using a JOptionPane window requesting input for adding inventory, updating a current item's status, displaying the inventory, and quitting. If the user wants to update an item, we will display another menu asking for the index of the item to change. After we recieve the index, we will display another menu asking the user if they want to update the name, quantity or price, followed by a prompt for the new value. And as was the requirement when I did the assignment, we'll limit the size of the arrays to 10 items in inventory.
So far, this program isn't too bad. A few tedious things (beyond getting input) that I noticed included making the display String for a given item, like at this line String item = "Name: " + name[index] + "\nQuantity: " + quantity[index] + "\nPrice: " + price[index];. Consider this though- what would happen if there were no size limitations as to the number of items you could have in inventory (meaning we are now using ArrayLists in parallel instead of static arrays)? When you go to add or remove (which would be the next logical step) items, you wouldn't have to use a counter variable because the ArrayLists would automatically resize as soon as elements are added or removed from them. This gets a little sticky, however, when removing elements in the middle of the lists, as it is very easy to get attributes mixed up. For example, you could remove element 9 for the name list, but end up removing element 8 from the quantity and element 10 from the price list. This would completely mess up the data integrity and accuracy, plus it is very hard to debug this error.
Another logical step would be to sort the elements according to one of their attributes (name, quantity or price). Using parallel arrays, you have to enforce each step of the sort amongst all three arrays. So for example, if you sort the quantity array in ascending order, the changes aren't automatically affected throughout the other two arrays. This means that if you call Arrays.sort() on one array, it doesn't necessarily change the other two. And if you call Arrays.sort() on each of the three arrays, you have just sorted three arrays individually, so your name, qunatity and price array are all in order according to the values stored in them. However, you will have mismatched all the attributes from the item they are supposed to describe.
Now that we've seen the cons of parallel arrays, let's talk about the advantages of using classes instead. First off, the attributes representing each class are contained within the class. This means that the quantity, price and name cannot get mismatched like we saw when using parallel arrays. This also means that we only have to manage one collection, so it saves memory. Next, we can use methods to make our lives easier. This means that we can set up a toString() method in the class, and when invoked, it will return a nice formatted (to our specifications) String; and we can also use a single setter method so we can eliminate the group of if statements for updating an item. So in short, you are dealing with one variable that holds all the information and can have automated tasks set up instead of having to hard code each component as we saw above.
Now that we've discussed the advantages of classes, let's take a look into puttingputting them into use. To start, we'll take a look at designing a class to model an Item.
After looking at the Item class, I notice how it is a lot more organized than using parallel arrays, plus it provides a little tighter control on the attributes and more usability through many of its methods, most notably the toString() and update() methods. Now let's redo our Inventory program using the Item class instead of Parallel arrays.
As we can see, this program gives us tighter control over each Item because we don't have to worry about keeping up with which indices represent each Item. This becomes increasingly important as we move onto using resizable collections like ArrayList, and as we attempt to sort the Items by a given attribute (or multiple attributes). We also have the convenience of using methods defined in the Item class, something we didn't have the luxury of doing when using parallel arrays.
By using classes instead of parallel arrays, you will begin to get a better handle on Object-Oriented Programming. This will help you as you continue your studies of Java, especially as you come across more advanced OO concepts like inheritance, abstraction and polymorphism, in addition to helping you better organize your program.
|The one thing I can emphatically say iMOVING AWAY FROM PARALLEL ARRAYS . Use classes and objects instead! They will help you organize your code so much better, as well as develop modular and reusable components.
I would also encourage developers to use appropriate data structures. When choosing a data structure, using it should make your life easier, especially as the size of the problem grows. The structure should also provide an efficient and appropriate means of accessing data (ie., with Trees, it might take longerr to traverse the Tree, but it shouldn't take O(n^3) time to access a bottom-level element in the Tree). Some examples of appropriate data structures are Maps for finding the frequencies of occurrences for elements, Graphs for GPS systems, etc.
Regarding GUIs, always separate your GUI from your data and program state. Regardless of the UI (console, GUI, etc.), the way the data is accessed, modified, and organized shouldn't change. Generally, one should design DataManager and/or StateManager classes to handle this.
Also with GUIs, design your Components with OOP in mind. They should be modular, easily reusable, and extensible. If you are getting to the point where you are setting up a method to initialize and/or return a single GUI Component, then it is probably time to extend that Component and make it its own class.
These are just a few of the things I came up with off the top of my head.
|While on DIC, I've seen a bunch of threads all asking basically the same thing- how can I get better at programming? The simple truth is that programming takes practice writing and debugging code. It is not something that comes overnight. So for those of you relatively new to (Java) programming, I've outlined a list of topics in a sequence from total novice to advanced programming, with focuses on various aspects of programming from data structures to Graphics to Networking.
Stage 1: You might fall into this category if you've never written a line of code before. Some things I would cover include:
-Hello, World (print() vs. println(), \n escape sequence)
-Primitive data types (byte, short, int, long, float, double, char, boolean)
-Basic use of the String class and Primitive Wrappers for parse methods (ie., Integer.parseInt(String))
-User Input: JOptionPane vs. Scanner
-If, Else-if, else statements; switch blocks, basic while, do-while, and for loops
-Arrays and foreach loop
Stage 2: If you have completed all the Stage 1 topics with a decent proficiency or are in the AP Computer Science or comparable class, then you should work on these topics. Note that all of these topics are critical to sucessful programming in Java, so you should have a strong handle on them before going onto stage 3:
-Class design (constructors, instance variables and non-static methods, use of static)
-Abstraction, Polymorphism (method overloading and overriding), and Inheritance
-Interface design and usage
-Object-Oriented Design Patterns
-Working comfortably on a large project where most of the code is not yours.
Stage 3: If you have completed AP CS or Comparable Course and are proficient with all the above tools, then you may want to start on Stage 3 topics:
-Data Structures and Collections (Linked Lists, Stacks, Queues, TreeMaps, HashMaps, TreeSets, HashSets, Graphs)
-Advanced Generics (use of the wildcard operator and further parameterization; making your classes generic)
-Graphical User Interfaces (Swing and AWT), as well as Graphics and Graphics2D classes for animations
-Event-Driven Programming (possibly game programming)
-Proficiency at maintaining code, including refactoring
-Becoming comfortable with a domain-specific third party API. (i.e. something niche, not standard, and possibly poorly designed and a nightmare to work with)
-Finding performance bottlenecks and designing solutions.
Stage 4: This is the advanced stuff, for which you should have a strong understanding of the previous 3 stages:
-Networking, Client/Server design
-Interacting with Websites and Webpages (ie., creating an RSS Feed Reader would fall into this category, while getting the webpage source might be more stage 3 topic)
-Advanced Applications of Reflection
-Drag and Drop with GUIs
I'd be happy to update this lis
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How can an organization detect the onset of an attack on its computer network giving it time to respond quickly and block any intrusion or compromise of its data? Modern firewalls and other technology are already in place, but these have not prevented major attacks on prominent networks in recent months. Now, information technologist Heechang Shin of Iona College in New Rochelle, NY, has used game theory to develop a defense mechanism for networks that is more effective than previous approaches.
Writing in the International Journal of Business Continuity and Risk Management, Shin explains that with the tremendous growth in numbers of computing and other devices connected to networks, information systems security has become an issue of serious global concern. He points out that each incident might not only cause significant disruption to services affecting many thousands of people but for a commercial operation can take as much as 1 percent of annual sales, per incident. That number amounts to tens of millions of dollars for the average publicly listed company, Shin says.
Shin has now developed an effective anti-hacking tool based on a game theoretic model, called defensive forecasting, which can detect network intrusions in real time. The tool, by playing a "game" of reality versus forecast, wins when reality matches its forecast and it sends out an alert to block the intrusion.
Importantly, the tool works on real-time data flowing in and out of the network rather than analyzing logs, an approach that can only detect network intrusions after they have taken place. The game theoretic model continuously trains the tool so that it can recognize the patterns of typical network attacks: denial of service attacks, such as a syn flood, unauthorized access from remote machines in which login passwords are being guessed or brute-force tested, attacks by insiders with "superuser" or system root privileges or probing attacks in which software carries out surveillance or port scanning to find a way into the system.
In order to measure the effectiveness of the tool, Shin compared the approach using the semi-synthetic dataset generated from raw TCP/IP dump data by simulating a typical US Air Force LAN to a network intrusion system based on a support vector machine (SVM), which is considered one of the best classification methods for network intrusion detection. Experimental results show that the tool is as good as or better than the one based on SVM for detecting network intrusion while the tool adds the benefit of real-time detection
How do I create a Windows shortcut key?
Create a shortcut
- Open the folder or directory that contains the program you wish to create a shortcut for.
- Right-click on the program and click Create Shortcut.
- This will create a shortcut named "Shortcut to <your program>" in the directory you are in. If you wish to rename this shortcut, right-click the file and click rename.
- Once the above steps have been completed, you can copy or cut this shortcut and paste it anywhere to execute this program.
Assign shortcut key to that Windows shortcut
Once the shortcut has been created to assign a shortcut key to that Windows shortcut follow the below steps.
- Right-click the shortcut and click Properties.
- Click the Shortcut tab.
- Click in the Shortcut key box and press a letter. For example, if you press "p" the shortcut key will automatically be made Ctrl + Alt + P. Which means if saved when pressing Ctrl and Alt and "P" all at the same time will run that shortcut.
Using keyboard shortuts can greatly increase your productivity, reduce repetitive strain, and help keep you focused. For example, highlighting text with the keyboard and pressing Ctrl + C is much faster than taking your hand from the keyboard, highlighting the text using the mouse, clicking copy from the file menu, and then putting your hand back in place on the keyboard. Below are our top 10 keyboard shortcuts we recommend everyone memorize and use.
Ctrl + C or Ctrl + Insert
Copy the highlighted text or selected item.
Ctrl + V or Shift + Insert
Paste the text or object that's in the clipboard.
Ctrl + Z and Ctrl + Y
Undo any change. For example, if you cut text, pressing this will undo it. This can also often be pressed multiple times to undo multiple changes. Pressing Ctrl + Y would redo the undo.
Ctrl + F
Open the Find in any program. This includes your Internet browser to find text on the current page.
Alt + Tab or Alt + Esc
Quickly switch between open programs moving forward.
Press Ctrl + Tab to switch between tabs in a program.
Adding the Shift key to Alt + Tab or Ctrl + Tab will move backwards. For example, if you are pressing Alt + Tab and pass the program you want to switch to, press Alt + Shift + Tab to move backwards to that program.
Windows Vista and 7 users can also press the Windows Key + Tab to switch through open programs in a full screenshot of the Window.
Ctrl + Back space
Pressing Ctrl + Backspace will delete a full word at a time instead of a single character.
Ctrl + Left arrow / Right arrow
Move the cursor one word at a time instead of one character at a time. If you wanted to highlight one word at a time you can hold down Ctrl + Shift and then press the left or right arrow key to move one word at a time in that direction while highlighting each word.
Ctrl + Home / End
Move the cursor to the beginning or end of a document.
Ctrl + P
Print the page being viewed. For example, the document in Microsoft Word or the web page in your Internet browser.
Page Up / Space bar and Page Down
Pressing either the page up or page down key will move that page one page at a time in that direction. When browsing the Internet pressing the space bar will also move the page down one page at a time. If you press Shift and the Space bar the page will go up a page at a time.
This article will be useful for people who wants to speak in front of a crowd without any fear.
Glossophobia or speech anxiety is the fear of public speaking. If you have those sweaty palms, shivering hands, squeamish feelings in your stomach, rapid breathing, and a dry mouth before you go onstage, take comfort in the fact that you are not alone. In fact, it has been found that more than 95% of people are scared of giving a public speech or performing a public act and this goes way above death and spiders in the list of things that people fear the most.
We must understand that a little amount of stage fear is actually good. It helps us prepare and boosts up our adrenaline and pumps up our energy levels. But it should not be so acute that it starts to cripple our confidence and our career. Here are a few ways in which you can alleviate your stage fear.
Prepare and Practice
"A person who fails to prepare is a person who is preparing for failure”
The two Ps, thorough preparation and practice is the best possible key to a good presentation. Go through the material carefully and organize what you have to tell in a way such that the audience will find it easy to understand and assimilate. Anticipate all the easy and hard questions that may come your way while you do the presentation and also make a mental note of how best to answer those questions. This will prevent you from balking when someone asks a question. Once you are sure that you have prepared very well your confidence levels will automatically boost up and your nerves will hold longer than you had expected them to once you are on the stage.
Practicing again and again will go a long way in ensuring that you make a great presentation. Once you have decided on what you are going to speak, concentrate on how you are going to speak. The major work is done and so now we can start ironing out the nuances. Stand in front of the mirror and see how your body, and in particular your hands move. Notice your pitch and the speed at which you deliver the words. Too fast and it shows that you are nervous and your audience will have a hard time catching up with you; Too slow and they will start slumbering. Maintain a moderate pace so that they can ride along with you.
Come to terms with the fact that things can go wrong
Now that you have done your two Ps you must also accept the fact that you cannot control anything that is outside your sphere of influence. People from the audience can treat you with negative remarks or gestures but you should never allow them to get on your nerves. This can seriously injure your performance. The best trick to deal with this is to imagine your audience doing something silly (like wearing funny clothes, or having whiskers drawn on their faces). This will soothe you and make you more tolerant with your audience.
Also be aware that you can indeed make a mistake sometimes. After all everyone is mortal and we are prone to making errors. Every single person in the audience would definitely have had their own embarrassing moments. Accepting this can drastically reduce your fear of making a mistake.
Mug up your opening line so that even if you are too nervous to think, you can spit up the opening line. A few minutes into your speech you will start warming up.
It is very important that you relax the day before your big day. Take the speech thing out of your mind and indulge in something that you love. Listen to music, have a nice long bath, water your plants, rent a funny movie and laugh your head off. Make sure you get ample amount of sleep the night before the speech. This will leave you feeling fresh and confident the next day.
On your big day make sure that you eat something light. You don’t want to be feeling queasy along with everything else. Make sure that you arrive at your destination well before the scheduled time. But you also don’t want to arrive too early and spend a lot of time worrying about your performance. Once you are on the spot you can do some stretching, shoulder and neck rolls and arm swings to alleviate the tension in your muscles. Take a few deep breaths and try to relax. Smile, because studies have shown that when we smile we automatically tickle the pleasure sensors in our brain. Smells also have a relaxing effect on people (esp. jasmine and lavender). You can spray some on your Kleenex and inhale it to reassure your brain that everything is OK.
Tips and Tricks on Stage
Before you go onstage talk to someone to make sure that your voice is fine. Have a sip of water and then walk on to the stage with a confident upward posture. Remember that people are here to watch your performance and not to watch you. Try not to be self-conscious. If you feel your legs shaking, lean on the podium or try walking. Don’t carry notes with you as they will betray your trembling hands. Carry three by five cards that fit smugly in your palm. Don’t fidget or put your hands in your pocket.
Browse through the audience and identify a few friendly faces all around the room. When you are talking, take turns to look at those faces. This will give the illusion that you are making eye contact with everyone and will also prevent you from fixating at any one point of the room.
If you do make a mistake DO NOT panic. Instead be happy that the worst is over. Move on and complete your performance with aplomb.
Once you start practicing all this you will find that performing on stage is not a big deal after all. So purge all your self-doubts and deliver your speech with splendor and confidence
Dreaming of becoming someone great is one thing but planning, executing and achieving what one dreamt is a completely different thing.
Every person has a dream but not all of them succeed in accomplishing what he dreams; only those with a strong commitment and passion towards what they dream achieve them.
Here are some examples of such great people who have paved a path for themselves and reached great heights walking in them without looking back.
Fifteen years ago a young Harvard drop out made history through his expertise in computer software. Yes! It is none other than Bill Gates.
Born in an affluent family, Bill Gates showed excellence in his early school days itself and breezed through schooling to get a Bachelor’s degree in Harvard. It was here that he met his future business partner Steve Ballmer.
Being a part of the team that wrote Altair BASIC for Altair 8800 was the turning point for Bill Gates. He gained so much confidence in his programming skills that he dropped out of college and got in touch with MITS orMicro Instrumentation and Telemetry Systems.
He was just half way in his venture of developing a new version of programming BASIC for the microcomputer platform, but informed them that the work was complete and bargained for a huge price.
This is where luck played its role in Bill Gates life to make him the world’s richest person; he got a very high price and also completed programming the new version in a week’s time from the day he called.
Bill Gates success is a clear illustration that shows that self confidence when combined with hard work never fails.
Well, for people who sought inspiration from their own generation Bill Gates’ story might seem history. However, the success story of Mark Zuckerberg, the founder of this era’s most famous social network Facebook, would make all the difference.
This 26 year Harvard graduate who revolutionized social networking hails from an educated family. Mark showed interest towards computer programming from his childhood days especially in connecting people and gaming.
His passion towards socializing and bringing people into each other’s social circle grew and led to the bringing up of a protocol program that was similar to the present Facebook. It worked well with students in Harvard University.
Slowly the facebook as it was initially called became prominent among student community and with time grew to such a huge presence that it handles the complete advertising of Microsoft. Now the 26 year old computing geek is one of the most famous persons in the world.
These two are not the only people whom you could get inspiration from; there are hundreds of other people around the world who have arisen to Himalayan heights from ashes. These people do not have any new power or magical wand to bring their dreams to life; everything lies in hard work and dedication in what they do.
Every person has the capability to do what he wants but the right choice and passion is what makes successful people emerge victorious against all odds.
Some of the famous college dropout billionaires are as follows.
1. Bill Gates - Microsoft Founder - US
2. Mark Zuckerberg - Facebook Founder- US
3. Mukesh Ambani - Reliance Group - India
4. Lawrence Ellison - Oracle - US
5. Eike Batista – EBX Group - Brazil
6. Steve Jobs - Apple Inc –US
7. Michael Dell - Dell Inc - US
8. Marc Rich - Commodities Trader - US
9. Ty Warner - Ty Inc - US
10. Gautam Adani – Adani Group – India