The influence of Smartphone Apps on Handheld game console market

LAM YAT HANG

    Starting from 1976, with the invention of the first handheld game console, playing video games was not restricted at home or game center anymore. We started to see people playing video games when waiting for buses, queuing for tickets or even attending lectures. Handheld game console allows us to have fun anytime at anywhere.

    More than 40 years have passed, today handheld game console is still very popular among people. It is not difficult to find people holding a PSP or NDS on the street. PSP and NDS, as the two consoles having the most competitiveness in the market of handheld game, starting their competition in 2004. They were both first introduced in 2004 and hit the market at that time. Until now, the PSP has sold for more than 71million units and NDS has sold for more than 147million units. With the release of new versions of the two consoles, their sales are still going. In 2009, the NDS shared 70% and PSP shared 11% of the portable game software revenue in the U.S. It seems that in the market there is no another console can complete with them. However, if you also consider mobile phone as one of the console, they really get a strong competitor.

    Many people may wonder if mobile phone can be considered as one type of consoles. Before appearance of the iOS and the Android system, the games installed in the mobile phones were usually simple games like “Snack” and “Minesweeper”. The mobile phone games usually had lower quality than that on traditional game consoles and didn’t be very popular. Therefore, people didn’t consider mobile phone as one of the handheld game consoles. However, with the appearance and popular of the iOS, Android system and Smartphone in recent years, game developers start to put more money in this market to develop more and better games. The games are not simple any more, some of them even have a big hit in the world like the Angry Bird and Fruit Ninja. These years, we can usually see people playing video games on the street, holding not a NDS or PSP, but a mobile phone. Due to its popularity and success, many people start to consider mobile phone as one of the handheld game consoles.

    Is that mobile phone really intimidating other consoles? Recently a research find that the market share for iOS and Android in the U.S portable games revenue raise from 19% in 2009 to 34% in 2010 and is predicted to further increase in the following years. While the market share of iOS and Android system increase by 15% in a year time, the one of NDS and PSP decreased 13% and 2% respectively. Many researcher believe that appearance of Smartphone and its applications, which called as “Apps”, is one of the factors that make the market share of traditional game consoles decline.

Some news also reported that the Nintendo Corporation, the corporation which invented NDS, has classified the iOS and Android system as their strongest competitor in the market of handheld game.

What makes Smartphone a strong handheld game console? Mobile phone is considered as a must-have item for people living in cities. In 2011, the Smartphone makes up 40% of all mobile phones in the market in the U.S and is expected to increase further in the future. It shows that Smartphone is also becoming more and more popular. Before the appearance of Smartphone, people need to bring an additional device like NDS or PSP with them for playing video games. Many people at that time need to bring their cell phone together with a console when they went out which was a little inconvenient. Many people did not own a cell phone and a game console at the same time. However, Smartphone changes the situation. Smartphone combines mobile phone, game console and even computer together. People bring a Smartphone with them are just like bringing a game console at the same time. With the device on hand, people are more likely to play video games. Although not all people use Smartphone to play video games, but a research find that 29% people will do so. With the amazing sales of Smartphone in the recent years, Smartphone had sold for more than 100million units in the 4th quarter of 2010, it can be said as the console having the most consumers.

Apart from that, Smartphone also provides a more convenient way for their consumers to get video games. The video games in the Smartphone are downloaded in form of applications, which usually called as “Apps”. All Apps are downloaded from the web and no exception for the game Apps. When people want to have game, there is no need for them to go to a shopping centre or waiting for the delivery if they buy it online. All the actions for buying Apps are being instant. The consumer just need to press an icon and their Apps will be downloaded and installed in their Smartphone. From the time that a person has a idea to have a game Apps to the time which he can play the game, the whole process takes no more than 5 minutes. The convenient of the process encourage people to enter the Apps market and have their game Apps. The sales revenue and the game developers will definitely be beneficial to this.

With the increase in the market share for Smartphone in the handheld game console, it is expected that more game developer will enter the market and provide more games for consumers. With more choices, more consumers will also be attracted. This forms a virtuous cycle and the Smartphone market share in the handheld game console is likely to further increase in the following years.

Reference

1. http://blog.nielsen.com/nielsenwire/online_mobile/40-percent-of-u-s-mobile-users-own-smartphones-40-percent-are-android/
2. http://blog.nielsen.com/nielsenwire/online_mobile/mobile-snapshot-smartphones-now-28-of-u-s-cellphone-market/
3. http://thegadgetsite.com/2011/04/nintendo-ds-and-psp-losing-market-share-due-to-android-and-ios/
4. http://www.weiphone.com/iPhone/news/2010-05-15/Statistics_say_iPod_iPhone_hit_DS_PSP_sales_216609.shtml
5. http://news.newhua.com/news/2011/0104/112578.shtml
6. http://blog.sina.com.cn/s/blog_5025e3880100ot99.html
7. http://www.gamasutra.com/view/news/37715/comScore_29_Of_US_Mobile_Phone_Subscribers_Play_Mobile_Games.php
8. http://www.hksilicon.com/kb/articles/34964/iOSAndroid-2015
9. http://www.eurogamer.net/articles/2011-09-14-ps3-worldwide-sales-reach-51-8-million
10. http://www.nintendo.co.jp/ir/library/historical_data/pdf/consolidated_sales_e1106.pdf

Grid Computing: Future Development

Wong Lok Kwan

Grid is an infrastructure that enables heterogeneous geographically separated clusters of processors to be connected in a virtual environment (network). Grid computing is a technical means to solve problem by sharing and applying the resources of many computers in the network. There are three main reasons that make grid computing popular. The first one is making more cost-effective use of a given amount of computer resources. Besides, it is a good way to solve problems that can't be approached if not enough amount of computer power is provided. And the last is that it suggests that all the resources of the member computers can be cooperatively harnessed and managed as collaboration toward a common goal.

Due to its many advantages, some models are developing and designing in progress for grid computing. Examples are as follows. 

Corba, it is a set of facilities linked through “off-the-shelf” packages. It is a client server model using web based technology. And it wraps the existing code used in Java objects. What is more, it utilizes current public key security techniques. Furthermore, it also exploits thread level and object level parallelism.

Legion, it is a single unified virtual machine that tying a large number of objects and processors together. This is object oriented machine. Each object defines the rules for access so that the object interfaces will be well defined. In addition, there is a core set of objects which provide basic services. So, the users can create and define their own objects easily and in a comfortable way. Besides, legion works with high performance, users can first consider the load and job affinity then select the hosts. The presence of object wrapping characteristic help to support the parallel programming. And because the user autonomy exists, users can choose security arrangements as well as the scheduling polices.

Globus, it is an integrated ”bag” of basic grid services. Its middleware layered architecture structure helps to builds global services on top of core local services. Apart from that, translucent interfaces to core Globus services, well defined interfaces that can be directly accessed by applications. In addition, its system can be improved like incremental implementation or other existing tools can be enhanced or replaced if needed.

In fact, grid computing has been promoted as the global computing infrastructure of the future for several years. Some scientists even considered grid computing as one of the major sources of the impact to technological and scientific changes on the society and economy, because of the fact that the usage of large amount of data becomes crucial to many aspects.
However, there are still some challenges existing, including the latency limitations, improved protocol schemes, and additional grid-based tools are needed.

But the most important thing is the cost problem. In order to amortize the substantial costs of managing these large data volumes (the key property of computing grid), the cost will usually be shared by scientists. Besides, large IT system is required to exploit the huge amount of data volumes. However some disciplines with no experience in administrating and managing these complex systems will be affected. These users can neither afford to establish a sufficiently large local compute nor to manage suitable IT systems by their own. Although the significant investments in the grid concepts, it recently draw less attention. Instead, some new concepts like cloud computing seem to replace it.

In fact, computer users will give up if the expected benefits dwarf the transition costs. In this way, we have to enhance the both sides. Many of the publications enhance the eventual benefits, but at the same time should we focus on the transition costs for the user? Can we identify user groups who want to use grid computing so that they may help us to make the system becomes mature then to reduce transition costs? However, this approach will focus on the core services and may create barriers in building a grid with higher level services. But we should consider carefully that do most users actually need such a high level services grid?

In short, there are many advantages of grid computing which is worthwhile to use it. But the inevitable fact is that there are still many problems should be solved first. If those problems are solved, grid computing will be one of the best techniques.

Mobile Device Security: iOS vs Android

Nowadays, it is not uncommon to observe most people around have a mobile device such as smartphone and tablet computer. These devices allow us to stay connected 24/7. The ability for the users to install applications has expanded their usability and thus increased their popularity. However, only a few users are aware of the security aspects of this technology. In this survey, I will compare security features of the two most popular mobile platforms: Apple’s iOS and Google’s Android.

Both iOS and Android have built in security features that were implemented based on four pillars: Application provenance, encryption, isolation, and permission-based access control.

Application Provenance
Application provenance is the technique used to ensure application authors and distributors have an identity that tides to the application.

Apple takes a tight provenance approach to ensure the authenticity of the iOS applications. Every application must be signed by an Apple-issued digital certificate. Apple will verify the identity of the developer and company before issuing such a certificate. Moreover, with the exception of the applications developed under Apple’s iOS Developer Enterprise program, all iOS applications must be published through Apple’s App Store and are subject to vetting by Apple. With a few exceptions, Apple’s approach has been proven to be quite effective.

On the other hand, Google took a relatively loose provenance approach. Although every Android application also must be digitally signed by a certificate, it does not have to be a Google-issued certificate. You can even self-sign the application with an anonymous certificate. To make the matter worse, applications may be posted on the Android Market without vetting by Google, and publishing applications through other channels such as the developer’s website is also allowed. As a result, an attacker can potentially attach malicious codes to a legitimate application, self-signed it and publish it on a website and those non-tech savvy users probably will not notice the differences. As a result, Android is more prone to attacks through polymorphic malware and trojanized legitimate applications.

Encryption
Encryption is the technique used to prevent data loss through unauthorized access. Without the decryption key, the data will look like garbage.

On the latest iOS devices, all data stored in the internal flash memory are encrypted using hardware-accelerated AES-256 encryption. iOS will automatically decrypt the data when it was read. Other data such as email and attachments can be secondarily encrypted by a user passcode. However, such an encryption scheme only provides little protection. A simple jailbreak will allow the attacker to read most of the data including the passwords stored because iOS stores a copy of the decryption key around to decrypt data for the applications running in the background.

Until the recent Android 3.0 release, there was no built-in encryption support on Android devices. Which means most of the Android devices on the market solely relies on the application to conceal sensitive data using the Java encryption API. Otherwise, all data are stored unencrypted on the device. So Android isn’t any better in terms of data loss protection.

Isolation (Sandboxing)
Sandboxing is the technique used to limit access to data and systems. Applications are therefore isolated from each other and the OS.

Applications running on the iOS can only access to a limited set of data such as contacts, calendar and the device ID. But they are blocked from accessing the emails and SMS inbox. User inputs is required if they want to do more, such as initiating phone calls and sending SMS messages. Also, applications are limited to user-mode ones and are blocked from accessing other applications’ data or enumerating other applications and the OS. This isolation model is effective on keeping the applications from causing too much mischief but at the same time also limits the ability to create iOS security applications.

Android on the other hand relies on its Dalvik virtual machine to enforce the isolation. Just like other Java-based platforms, applications on Android are run within its own virtual machine, which is isolated in its own process. Applications are also limited to user-mode ones and are blocked from accessing most system services by default. Although Android limits application’s access to other application’s private data, it allows applications to enumerate and examine other application’s codes. Also, data stored on the external SD card can be read by all applications by default. With the exception of the SD card, Android has an even stricter default isolation model than the iOS and the ability to access other application’s codes make it easier to create security applications.

Permission-based Access Control
Permission-based access control is the technique used to limit access to the data and systems to the ones granted by the policy.

Apple hardwires the access policy into iOS. The only exceptions are the permissions to access to the GPS location data, receive alert notifications, initiation phone calls, and send out emails and SMS messages, which the application can prompt the user and request for permission. So iOS applications do not really have any control over most of their permissions

Unlike iOS, Andriod applications may request granular permission to almost every subsystem. Developers explicitly state the set of permission at compile time and the user can either accept or reject all permissions at install time. While this approach provides greater flexibility to the application developers, it also relies on the user to decide whether it is safe to grant the requested permissions. With over a hundred of different permissions an application can request for, it is difficult for an average user to make such a security decision. This leaves a giant security hole in Andriod.

After reviewing both features of two mobile operating systems, it is obvious that they are different system. Although both platforms are designed with security in mind, users cannot solely rely on these security features to protect their data as there are weakness in both platforms which could open up to attacks. While it is convenient to use these mobile devices to stay connected, users should also be aware of the security implications, and be more educated about mobile security so that they can better safeguard their data.

References:
1.    Android Developers. (2011). The Developer’s Guide. Retrieved from http://developer.android.com/guide /index.html
2.    iOS Developer Library. (2010). iOS Development Workflow Guide. Retrieved from https://developer.apple.com/library/ios/#documentation/Xcode/Conceptual/ios_development_workflow/000-Introduction/introduction.html%23//apple_ref/doc/uid/TP40007959
3.    iOS Developer Library. (2010). Security Overview. Retrieved from https://developer.apple.com/library/ios/#documentation/Security/Conceptual/Security_Overview/Concepts/Concepts.html%23//apple_ref/doc/uid/TP30000976-CH203-TPXREF106
4.    Nachenbery, C. (2011). A Window Into Mobile Device Security. Retrieved from http://www.symantec.com/content/en/us/enterprise/white_papers/b-mobile-device-security_WP.en-us.pdf

The Emergence of Web Applications

Applications are the most important component of a computer. Nearly every interface you use to interact with the computer can be classified as an application, for example, Internet browser, file explorer, and video player. Without these applications, computers will become unusable to most users. In 2005, Gmail brought the term Ajax to the world. It, together with the availability of high-speed Internet around the world, sparked the beginning of a whole new era of applications – Web applications. During these years, a myriad of innovative web applications are introduced – EditGrid, Google Docs, Photoshop Express, etc. While these web applications gain their popularity in an exponential rate, the traditional desktop applications have started to fade out. In other words, everything is moving towards the Internet.

Web applications are welcomed by most developers, software vendors and users due to several advantages of web applications over the traditional ones. The first and most apparent advantage of a web application to end-users is similar to a web site. Users can gain access to the web application anywhere and anytime as long as they have a computer and are connected to the Internet, which is now easily accessible with all the Wi-Fi access points spreading over the city. Web application does not require the users to install it locally on their hard drives before using them. It is more efficient and more readily accessible.

Web applications are commonly used in conjunction with cloud storage, like Google Docs. If a user has multiple computers, cloud storage will help the user to manage the files, maximize data consistency and even creating back up of the files. These are all the trivial tasks that the users have to do when they use the previous generation desktop applications. Web applications definitely deliver a much better user experience than traditional desktop applications.

Web applications are also welcomed by developers and software vendors because of several reasons. There is a variety of operating systems available – Windows, Macintosh, Linux, etc. Software developers used to develop desktop applications targeting each operating system individually. In this case, they have to spend a great deal of time tackling different compatibility problems. Development process is slowed down and less time is invested in creating new features. This is really a barrier of software development. However, due to the nature of cross-platform of the web applications, software developers can use much less time in solving compatibility problems. The developers can just create one version of the application and it will be available to most operating systems.

Software developers are humans and humans tend to make mistakes. It is extremely hard, if not impossible, to have a glitch-free software. This is the reason why software vendors have to push out software updates from time to time to eliminate newly discovered software bugs. There is a difficulty in this situation that users may not check for software updates regularly and that even if the software reminds them to perform an update, users may just ignore the notification. User experience is affected when they are prompted to update an application or when they encounter software problems because of not updating. Web application allows software vendors to rapidly deploy updates to the application as they have the full control of the server. Users will not notice any underlying changes of the application unless there is a change in the interface. The whole update process is more streamlined with web applications and user experience is improved.

The software vendors have the full control on who can access and use the web application. Piracy has always been the most concerned problem in the software development industry. With web applications, software vendors can issue user accounts to their paid customers to use the application. It is impossible for people to illegally make copy of the application as it must be accessed through the vendor’s server. The vendors can even impose stricter regulations on user accounts like forbidding concurrent login to secure their profits.

In conclusion, web application offers better user experience and more convenience to the end-users and, at the same time, greater flexibility and security to the software vendors. With benefits to the two parties, there is no doubt that web applications are going to replace most of our commonly used desktop applications. Perhaps one day Google’s Chrome OS will become the most used operating systems.

Whatsapp Messenger

Before the popularization of 3rd generation mobile telecommunications (3G) and Wi-Fi technology, people use Short Message Service (SMS) to text their colleagues, partners, friends and other people. Although handy, SMS has several drawbacks itself. The messaging cost is sometimes a trouble-some problem and the character limit of one message also poses a barrier to people using standard SMS as an exchange of information. Using other types of instant messaging tools on smartphones cannot solve the problem either because of compatibility issues. But now as Whatsapp Messenger (Whatsapp) emerges, these problems seem to be solved. This survey will focus on the working mechanisms of Whatsapp and how it affects the society.

Whatsapp is messaging software available on several popular mobile operating systems, including iOS, Android, Blackberry and Symbian. It makes use of internet connection, instead of cellular connection used by SMS, to deliver messages from one phone to another.

When a person sends a message, Whatsapp will deliver the message to the server. The server will then deliver the message to the destination. No matter what kind of smartphone the user is using, as long as it is installed with the messenger, the messages can be delivered to the phone and can be seen. The compatibility issues do not exist. Other than simple text, Whatsapp message can also be consisted of photos, videos and audios.

As 3G and Wi-Fi technologies are gaining popularity all around the world, and more and more people are replacing their cellular phones by smartphones, the number of Whatsapp users is growing. Its cross-platform feature also enables people to exchange messages between different brands of smartphones. In addition to the basic text messaging functionality, it also supports multimedia messages, which enriches the context of the messages. More importantly, it connects to the server via the Internet, and only requires the user to have a data plan for the 3G services or to have access to Wi-Fi coverage; the cost of messaging is much reduced.

All in all, the emergence of Whatsapp provides a more convenient way for people to send instant messages with enriched context and a lower cost. It can be foreseen that in the future, as the cost of 3G services getting cheaper, Whatsapp Messenger will gradually replace the standard SMS as the major messenger tool in the society.

The Wolfram Alpha search engine

A new search engine called Wolfram Alpha is launched officially on May 15, 2009. In fact, it is a computation knowledge engine rather than a search engine. Instead of giving users some websites which may contain the information they look for, Wolfram Alpha can compute answers and relevant visualizations to factual queries from its knowledge base of structured data. The designer of Wolfram Alpha, Stephen Wolfram, believes that it will change the way people use online data.
   
This short survey will focus on the principle of Alpha’s question answering feature and how it will affect other weds.

With the help of sophisticated Natural Language Processing algorithms, Alpha can understand the meaning of input fed by a user and try to provide answers from its vast repository of data relevant to the likely cultural stance of the user. For example, even two users enter the same word "Cambridge", the one with a UK-based IP address  will receive the data about the Fenland City while the one with a US-based address will receive the data about the Massachusetts Town.

The performance of Wolfram Alpha greatly depends on the scale of its curation system. It stores huge amount of information and algorithms. Mathematica, a powerful tool for scientific computation, is used to manage such a large-scale data curation system and help Wolfram Alpha compute answers.

Mathematica does not only include algorithms for mathematical computation, but also the whole spectrum of logical, numerical, graphical, symbolic, and other computation. Meanwhile, the fundamentally symbolic nature of the Mathematica language allows an unprecedented degree of interoperability between different parts of the system, and between different algorithms and data sources. For example, if you search for "China GDP", Wolfram Alpha will generate a graph and other relevant economical data to you.

Inside Mathematica, a technology called Automatic algorithm selection enables Mathematica to select and apply the best algorithm(s) for a given task. So Wolfram Alpha can generate answers with high order of accuracy. For example, "lim(x->0) x/sin x" yields the expected result, 1, as well as a possible derivation using L'Hôpital's rule.

In terms of technology, Wolfram Alpha is entirely developed and deployed with Mathematica and Mathematica technologies. It is built on top of 5 million lies of Mathematica code which currently run on top of about 10,000 CPUs. In order to serve the public, a software called gridMathematica which increases the number of parallel processes that Mathematica can run at once is introduced. By increasing the number of tasks available, some types of problems can be solved in less time

Wolfram Alpha is an amazing product combining computational capabilities with linguistic processing capabilities. Due to its direct answering feature, many people compare it with Google search and call it "Google killer". Although Wolfram Alpha is powerful, it may not beat Google. Wolfram Alpha can only turn generic information into specific answers for factual queries. If we use it to search for a song called "sad but true", it will provide us the information about depressed. Furthermore, Google is a company but not a technology. In addition to its quality, the success of Google search also rely on its marketing, sales, customers, developers, brand reputation and luck.

However, Wolfram Alpha will probably be a worthy challenger for Wikipedia and many textbooks and reference works. Since users can get a direct answer to their question together with a nicely presented set of graphs and other information when they look for basic encyclopedic information, people will gradually replace them with computation knowledge engine like Wolfram Alpha.

In conclusion, even though Wolfram Alpha is not a perfectly mature technology, it shows the future trend of search engine. It is foreseeable that future search engines will like AI. Humans can normally communicate with them through natural language and they can respond to us with satisfactory answers directly. 

Reference
1.    http://news.bbc.co.uk/2/hi/technology/8052798.stm
2.    http://en.wikipedia.org/wiki/Wolfram_Alpha
3.    http://www.theregister.co.uk/2009/05/18/wolfram_alpha/
4.    http://www.readwriteweb.com/archives/wolframalpha_our_first_impressions.php
5.    http://blog.wolframalpha.com/2009/05/01/the-secret-behind-the-computational-engine-in-wolframalpha/
6.    http://www.wolfram.com/technology/guide/AutomaticAlgorithmSelection/
7.    http://www.wolfram.com/mathematica/how-mathematica-made-wolframalpha-possible.html
8.    http://en.wikipedia.org/wiki/GridMathematica
9.    http://bits.blogs.nytimes.com/2009/03/09/better-search-doesnt-mean-beating-google/

Are Facebook games eating up your life?

Nowadays, many people from different places like to use Facebook online. That is a growing trend of the world. Facebook is becoming much and much more popular. Many people love to use Facebook when they get free. There are many different applications and games on Facebook. Facebook users usually use these applications or games while using Facebook. From statistics, there are more than 800 million users on Facebook and 53% of them play games on Facebook. Maybe you are one of the Facebook users who play games on Facebook. Will your ever think that playing Facebook games are time consuming or wasting your time? This survey would go through the question.

Firstly, let’s discuss the reasons of people playing Facebook games. People who play Facebook games usually said that they play Facebook games because they want to be social, to engage, to immerse, etc. The first reason is that most of the popular games on Facebook are easy to learn and easy to play. They are attractive to most of the Facebook users. Once they saw their friends play some new games on Facebook, they will also try to play them. These games can be very addictive and may cause players lose lots of time for working or studying. Players may even need to sacrifice their sleeping time. One of the other reasons is that people do not know how to spend their free time. While they are free, they try to log on Facebook and use different applications or games to consume their time. Playing Facebook games is also a good way for people to spend their time. They may even not know why they play these games, just for consuming the time. They strive for nothing.

The next point is to talk about what are the effects acting on the people who play games on Facebook. Surely, people can get entertained, that is the greatest advantage to human’s life. But there are many negative effects on that, especially on their time. Playing Facebook games is time-consuming and the time will be wasted. This situation occurs especially on the people who get addicted on playing Facebook games. They spend most of their time on it.

Here is the table of top 5 parent companies for January 2010.

Top 5 Parent Companies/Divisions for January 2010 (U.S., Home and Work)
Rank	Parent	Unique Audience(000)	Time Per Person
1	Google	162,536	2:05:19
2	Microsoft	143,893	1:57:58
3	Yahoo!	138,850	2:28:33
4	Facebook	116,329	7:01:41
5	AOC LLC	87,629	2:14:12

From statistics, the average time spent on Facebook per month by each user is 421 minutes, which is about 7 hours. Then by calculations, we can obtain that 927 million hours are spent on Facebook games per month, which is a very large figure. This figure indicates that a large amount of human resources are wasted. If these 927 million hours are spent on other fields, great efforts can be made. Also, some people will devote their money into Facebook games to gain some benefits in games. They used something real to pay something virtual. They spend time to earn money, and they spend more time and the money to buy things virtual. That means they have to pay double cost to exchange these benefits which are not worthy.

To conclude, Facebook games should be eating up our life. But surely, it depends on that how do you play games on Facebook. Whether you can control yourself or manage your time probably can also avoid Facebook games eating up your life. They can entertain you if they is used probably, otherwise they will become drugs. Someone who is fallen into Facebook games before said, the key to keep balance is to let yourself play the games and do not let the games play you. Do not be the next Facebook games’ victim.

References

1. 10 Mind Blowing Facebook Games Statistics : http://www.allfacebook.com/facebook-games-statistics-2010-09
2. Facebook Statistics : http://www.facebook.com/press/info.php?statistics
3. Facebook Users Average 7 hours a Month in January as Digital Universe Expands : http://blog.nielsen.com/nielsenwire/online_mobile/facebook-users-average-7-hrs-a-month-in-january-as-digital-universe-expands/
4. Why do people play games on Facebook? : http://playaslife.com/2010/04/08/why-do-people-play-games-on-facebook/
5. How to control your Facebook games addiction? : http://gameolosophy.com/games/how-to-control-your-facebook-games-addiction/

The Wolfram Alpha Search Engine

Wolfram Alpha is a brand-new search engine. One expert said it "could be as important as Google". What is so special about this new search engine?

Wolfram Alpha is developed by Wolfram Research. Scientists is already using this company’s previous creations, the computer program Mathematica, to help them with their work. Same as this former program, Wolfram Alpha is also mathematic. But this “answer-engine” not just can help you with mathematic works. It can do something more.

The term “answer-engine” means that Wolfram Alpha is “question answering”. The engine would understand your question, then answer your question. For example, typing “which is the tallest building in the world?”, Wolfram Alpha will answer you “Burj Khalifa”. Searching for “lim(x->infinity) (x^3)/(x+5)^3”, Wolfram Alpha will answer you “1”. When compared with Google, or other ordinary search engines, which would gives you websites containing your keywords, Wolfram Alpha’s results would truly amaze us.

Wolfram Alpha is expected to be successful, even can be compared with Google. Before this search engine appeared, it was far more inconvenient to find the answer of our question. Searching on Google gives us a lot if irrelevant results; Reading and searching on books is very time consuming; asking teachers or lecturers is not always possible as we seldom meet. Thus, Wolfram Alpha will be the best choice of search engine when we are looking for answer of a certain question.

Wolfram Alpha also outstands with its sophisticated knowledge. We can easily search for accurate and detailed physics or chemistry data on it. It can also act as a dictionary, giving us several definition of a certain English word. Stephen Wolfram, developer of this engine, also showed us searching examples for nutritional information, weather, and census data in a demonstration. The abundance and flexibility of Wolfram Alpha is astonishing.

Although it has some advantages over Google and other search engines, it is quite different from other search engines. Sometimes what we are looking for are some webpage, some photos, some articles, some wider variety of information, rather than an exact solution. Therefore, there would not be direct competition between these engines.

With its unique and convenient features, it is believed that Wolfram Alpha would become as famous as Google. Its success can even induce other companies to develop new technologies of search engines, not just blinded to the old format webpage search engines.

References

1. http://blog.wolframalpha.com/2009/05/15/wolframalpha-is-launching-made-possible-by-mathematica/
2. http://www.readwriteweb.com/archives/wolframalpha_our_first_impressions.php
3. http://en.wikipedia.org/wiki/Wolfram_Alpha
4. http://www.wired.com/epicenter/2009/05/wolframalpha-fails-the-cool-test/
5. http://www.guardian.co.uk/technology/2009/mar/09/search-engine-google
6. http://blog.wolframalpha.com/2009/05/12/going-live-and-webcasting-it/

Microblogging -- Twitter & Sina Weibo

Liu Songling

Introduction

Twitter is an online social networking and microblogging service that enables its users to send and read text-based posts of up to 140 characters, informally known as "tweets", and images.

Sina Weibo (Chinese: 新浪微博; literally "Sina microblogging") is a Chinese microblogging site. Akin to a hybrid of Twitter and Facebook, it is one of the most popular sites in China, in use by well over 30% of internet users, it has a similar market penetration that Twitter has established in the USA.

Rapid Development

Twitter was created in March 2006 by Jack Dorsey and launched that July. Twitter rapidly gained worldwide popularity, with 200 million users as of 2011, generating over 200 million tweets and handling over 1.6 billion search queries per day. It is sometimes described as the "SMS of the Internet."

Sina Weibo was launched by SINA Corporation in August 2009, and now has more than 200 million registered users. A two-year-old block on Twitter setting being accessible in China has allowed Sina’s homegrown Weibo to flourish - and now it’s blossoming in to far more than a Twitter-style microblogging tool.

Social influence

a. Twitter

As one of the most popular social network sites in the world and with more than 10 languages in used, Twitter has an indisputable influence in both the daily life of humans and issues of the society.

Nowadays, people spend an increasing time chatting online or with cell-phones, with great interest in what their friends or some other famous people are doing. Thus as a convenient internet posing wall for users to update their moods, status just via text-based posts, twitter not only provides the commenting and chatting services like Facebook, but also let users become “followers”, which enable users know not only their friends’ status but also other famous people,  their interested companies, organization and so on.

“Followers” in twitter, like fans or supporters, by leaving comments or reply to a status can somehow show their supports or arguments, and can even reflect the public opinion on a certain social event. For example, in August, 2009, when the opponents of Obama’s health care reform plan aggressed the National Health System (NHS) of UK, thousands of the users of NHS used the #welovetheNHS label in twitter to support NHS and refute the campaign of U.S.Right, winning the Prime Minister Gordon Brown’s support and respect.

b. Sina Weibo

Owning similar services with Twitter, Sina Weibo, though established only 2years ago, now also has a great influence in the society. Mainly used by people in China, the impact of Sina Weibo largely focuses on the care of the life of people. People in Sina Weibo not only share some advice and tips of daily life, but also warm-heartedly post some advertisement on emergent need of hospitals and disaster area. For instant, the reason why Yao Chen becomes the Queen of Weibo is not just the humor language she used in her post, but her consistent post for the people in urgent need for help. People love to see that famous Weibo owners take advantage of their large amount of fans to help others with widely advertising instead of promoting products.

Also, like news broadcasting, Weibo users report and describe the real situation of big events and disasters, enable people in the nation get the fastest information. For example, in the disaster of the train crash in Wenzhou China, on 23rd July, 2011, people post the condition of the crash and the people injured in Weibo, which was more informative and timely than TV news report.

Advertising effectiveness

a. Twitter

While hesitation over making purchases for products through the networking sites has abated, what along with the widely use of Twitter, of course, is the great profit from advertisements. While Facebook may take the lion's share of social media marketing budgets, Twitter is fast catching up and eMarketer has estimated that worldwide advertising revenues will rise by 210 per cent by the end of this year. This represents moving from $45 million (£28.7 million) earnings in 2010 to an expected $139.5 million (£88.9 million) by the end of 2011. The marketing analysts also forecast that Twitter's worldwide ad revenues will reach $400 million (£255 million) by 2013.

Also, economic advantages come from the cooperation between mobile phones and Twitter. For example, Samsung announced the launching of Galaxy S, a Smartphone manufactured by Samsung, in Korea in detail via the Twitter. Usages like these certainly helped people in terms of receiving information quickly. This not only enables people to use Twitter with smartphones at anytime in anywhere, but also decrease the cost of communication. It is estimated that over half of Twitter users use their webpage by mobile devices. While other online services such as blogs and MSN Messenger require people to be stationed, Twitter can be accessed while moving. Moreover, other online communication systems such as MSN Messenger ask users to sign in. This means that people have to stay in their seats in order to use the system, which is a huge inconvenience.

b. Sina Weibo

Via such kind of social network, not only companies advertise their products by posting ads, but users publicize the products they love by showing their pictures and comments. Recently, it has become a trend that users would love to post what they have bought and what they have eaten on Sina Weibo, which then cause a great popularity of the product or the restaurant that is appreciated and forwarded by many other users. Since people would rather believe what their peers and friends preferences, thus the effectiveness of such advertising may much more powerful than TV ads. 

Conclusion

Though I just talk about the development, social influence and advertising effectiveness above, there are many other information and benefits of these two social networks. However, apart from their advantages, they also have their respective limitation. For instant, Twitter has no constant, long-term income source, which makes it hard to decide whether to choose the profit from companies’ advertisement or the users’ favors, as it may worsen the perception of users about twitter if it intentional creates a platform for advertisements. Also, Sina Weibo only has Chinese version which greatly limits its development and expansion. 

Reference

1. http://zh.wikipedia.org/wiki/Twitter
2. http://en.wikipedia.org/wiki/Sina_Weibo
3. http://www.equimedia.co.uk/index.php?id=98&article=800744322
4. http://ahnyoungjae.wordpress.com/2010/12/12/economic-benefits-and-limitations-of-twitter-and-the-future/

Is it secure to shop online?

With the growing in popularity in surfing the internet among the public across the decade, online shopping has become a widespread activity in our daily life. No matter what you can think of, almost all the products and service are available on the internet, which vary from groceries to clothes, from cars to house. A research conducted by Pew Internet in 2008 revealed that over half (66%) of the online American admitted that they have purchased a product online, and most of them thought that it is convenient (78%) and time saving (68%). Despite the benefits online shopping bring us, it draws some concerns over the security problem of data transmission. 75% of internet users worried about the safety of sending personal details or financial information such as the credit card number over the internet. Is it safe to shop online? How to ensure the security of online shopping or e-commerce? What can we do to protect our personal information from leakage? In this survey, I would like to focus on the precautionary measures to better protect ourselves so as to enjoy a safe and comfortable online shopping experience.

1. Web sites with secure transmission
The first measure is to look for secure web sites which use the secure transmission standard such as Secure Sockets Layer (SSL) and Secure Electronic Transaction (SET). It ensures secure transmission of data between a web site and its client by using Public Key Infrastructure (PKI). When sensitive data is needed to sent over the internet from the client, the public key of the web site is obtained to encrypt the data. It can only be decrypted by using the company’s own private key which must be kept secret, ensuring the security and maintaining the confidentiality of the message no matter when it is intercepted during transmission. An SSL web site can be identified by a symbol of a closed lock icon in the status bar or the protocol prefix “https” in the Uniform Resources Locator (URL). (Chan W. N., 2005) The following is a web site with SSL.

2. Verifying a site by Digital Certificate
Using a digital certificate is another way to verify a web site to see if it is secure. It is a digital document including the name and the public key of a person or an organization, which is used to verify or identify that a person or an organization sending a message is who he or she claims to be. Checking the digital certificate of a web site by clicking the lock icon on the browser can easily ensure the security of transaction with the web site.

3. Looking for the Web Site's Privacy Statement
Checking out the “Privacy and Security Policy” of the web site can give you a clearer understanding on how your data is processed. To be more specific, you can find out what type of information is collected by the web site, whether your information is shared with a third party and how it is shared.  If your data is allowed to be marketed to others, you can probably expect to receive spam mails.

4. Be Aware of Cookies
Cookies are a small chunk of data generated by a dynamic web page and stored in a text file on your computer’s hard disk. (Chan W. N., 2005). It is an online tracking system that stores information such as your login name and even your password you sign in a site, the web sites you visit as well as your shopping and surfing habits. This data is useful for the companies to select and promote their products and services to you through targeted advertisements which suit your interests and shopping patterns. It is a common and useful marketing tactics for the companies to expose their products to their potential customers, which in turn has a higher chance to earn a greater profit. However, this data are stored secretly without your active consent. All this information may combine to form a detailed profile and may be transmitted to the third parties in the worst case. Although you are allowed to set your security settings to disable cookies, you may possibly not be able to make online purchase from e-commerce web site where cookies are needed for running the shopping carts.

5. Using single-use credit card numbers

Since your credit card number can be easily stolen from the customers’ databases by hackers, it is not secure to use it for online shopping. To tackle this problem, it is suggested to use the single-use credit card numbers or “virtual credit cards” to make purchase, which the substitute account number is generated on a random based for one-time usage only. This method can effectively keep your actual card number hidden while performing the transaction. Due to the single usage in nature, it can’t be used again for other purchase even if the card number is stolen from a hacker.

In conclusion, there are pros and cons in conducting e-commerce. It indeed brings us convenience and fun in shopping online without the restriction of the geographical boundaries and time factors. The number of online shopper will be soared rapidly if the public’s concern over the security and privacy problem of data transmission can be addressed. You may find the advice above useful in protecting your sensitive data while enjoying the fun of e-commerce.

Reference

1. Chan, W.N. (2005). Computer concepts. Hong Kong: Radian Publishing Co.
2. Chan, W.N. (2005). Data communication & networking. Hong Kong: Radian   Publishing Co.
3. Horrigan, J. (2008) Online Shopping. Retrieved from http://www.pewinternet.org/Reports/2008/Online-Shopping/01-Summary-of-Findings.aspx
4. Online Shopping and Security (n.d.) Retrieved October 4, from http://www.extension.iastate.edu/publications/pm1789g.pdf
5. Online Shopping and Tips: E-Commerce and You (2011) Retrieved from https://www.privacyrights.org/fs/fs23-shopping.htm

The Largest Marketplace on the Internet: eBay

Due to rapid growth of e-commerce, people nowadays can easily purchase goods and services at home. With increasing popularity of online shopping, there are more and more auction websites existing on the Internet. Among these, eBay is the largest and one of the most famous online marketplace for selling goods and services for individuals. In this survey, I will discuss the business model of eBay, followed by its security measures. Finally, my opinion on eBay will be made.

Business Model
eBay creates an online person-to-person marketplace where sellers list a variety of goods and services for sale and buyers can bid on their interested items. Instead of direct the transactions, these two online auction websites provide buyers and sellers with a platform to communicate during the transaction.

However, both eBay does not provide this platform free. Although buyers can browse and bid on auctions without being charged, sellers are required to pay for the transaction fees, including insertion fee and final value fee. Insertion fee is the fee that is charged when sellers list their item on eBay for sales. For final value fee, it is charged when the auction ends. Insertion fee and final value fee are charged based on the opening bid and final selling price of the sold item respectively.

Once the auction ends, eBay will notify both the seller and buyer through email. After that, the payment exchange is left to the seller and buyer.

Security Measures
In order to provide confidence to users in a safe and secure ways through the transactions, eBay established a number of security measures to protect users.  Firstly, registration is required for users before buying or selling items on eBay. Apart from this, user’s information such as the URL, browser software and IP address can be tracked by eBay. This can avoid users from creating more than one account in the same computer.

To avoid improper activities such as fraud and intellectual property infringement on the website, eBay runs the Verified Right Owner Program which assists in the investigations of these activities. If users are found violating the rules repeatedly, eBay has the right to disclose the users’ account to law enforcement. This makes the users have more confidence when using eBay.

Besides, eBay also protects the buyers’ right by providing refund. When the buyer cannot receive the bided item and cannot solve the problem with the seller, he or she can go to the Resolution Center and eBay will carry investigation the case.  If the problem is due to the seller, eBay will return full refund including the selling price and the shipping cost to the buyer.

After reviewing the business model and security measures established by eBay, it is not difficult to understand why eBay is one of the largest and most successful online auction websites in the world. However, whether security measures are useful and convenient for users is still questionable. Take Verified Rights Owner Program as an example, this program assist in the investigation of any intellectual property infringement on the website. However, it cannot identify whether the item sold is a licensed or unlicensed product.  If you sell second hand Nike shoes on eBay, eBay may suspend your account because you are not authorized to list Nike products by Nike and eBay will consider you are selling unlicensed product on the website. What you need to do next is to send email to eBay telling it you are actually selling the licensed items. And eBay will investigate the case that usually takes several weeks. During this period, the user’s account is still suspended. This causes inconvenience to sellers and in case if they want to create another account in the same computer, eBay can track IP address of users’ computers and prohibit users from creating a new account in the same computer. 

Undoubtedly, eBay system provides a good platform for people to online shopping or trading; however, there are many constraints which lower the efficiency of trading from sellers or buyers.

Cloud Computing

Poon Kwok Huen

Introduction
Cloud computing is a very popular concept applied in many internet websites and applications like Google and Facebook, but it seems that not many people what cloud computing is. Through cloud computing, users can just use their phones to connect to the internet and access software, platform and hardware provided by many other computers that are also connected to the internet. We can also perform computation of very large programs which even supercomputer takes time to solve with cloud computing.

Definitions
Actually, cloud computing is not a new technology, but only a concept about delivery of resources on internet. We can find many definitions of cloud computing on the internet and we may not have a clear idea about cloud computing, but we can still conclude some common characteristics and applications about cloud computing.

Cloud computing is to access internet resources by the users’ own internet devices and make use of the resources to do tasks. As internet is a very big collection of computers, cloud computing can also be described to be using the software and hardware resources of the other computers through internet. As we can gather the power of a large number of computers, we can perform powerful computing or provide computing services through internet.

Characteristics
In real life situation, cloud computing is used by large companies for delivering their services. They set up many powerful servers and develop applications for users to access, with some are charged and some are free of charge. This kind of service shares 3 properties:

1. The service is charged according to the amount of resources used, like the amount of time using the online service of the computation power used by the servers.
2. Users can use and cut the service as they want to, as well as they have no time limit or specified period. The providers put the services on their platform and users can use the service as they pay the required charge or cut the service by stop accessing the service.
3. The services provided are totally maintained by the providers, which are the companies. As the resources such as software and hardware are all owned by the companies, the companies are responsible to maintain the functionality of the resources so to maintain stable services.

These services are divided into 3 main types: Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS) and Infrastructure-as-a-Service (IaaS).

Software-as-a-Service (SaaS)
SaaS is to provide software for user to use online. Originally, individual users or companies need to buy the license of software for several years in order to use the software, and they can install the software at their computer to do their tasks. Now cloud computing allows the user to use the software on demand. The software is installed in the providers’ servers. When the user wants to use it, they can connect to the providers’ servers and use the software online. It can reduce the cost of the software for users in a small scale, and the software is kept to be the most upgraded version. Also, the requirement of hardware for the users’ computers is not high as they just need their device to connect to the computer, operate the software and receive the result, but not computing the content. Nowadays SaaS is focusing on commercial software, and some companies such as Salesforce are fighting for the SaaS market.

Platform-as-a-Service (PaaS)
PaaS is to provide a platform, including a set of software on an API, website portals or gateway software, for users to develop their own set of programs on the platform. As a result, PaaS is an entire service for users to develop their own software which fits them most. Also because the users develop the PaaS, it helps the improvement of PaaS and SaaS, creating more functions and applications for the platform. For example, Google provided the Google App Engine in 2008 for users to develop their apps, which is also a typical case of PaaS.

Infrastructure-as-a-Service (IaaS)
IaaS is to provide users with all the server resources, including start, stop, access, configure, storage, computing power, internet service and software. It is just like using a virtual machine online and you can do whatever you want. Base on the concept of on demand, a user can just use what he or she needs and leaves the other resources, so that the other resources for other usage. The most famous IaaS provider is Amazon EC2, which start running from 2006 and provide virtual machine with different configurations.
 

Conclusion
There are still many probabilities for cloud computing. The characteristics, definition and common service form stated above are just some brief introduction about the situation and application of cloud computing and the whole world is still looking forward to how cloud computing can lead the development of the commercial world, electrical world and our living standard.

References

1. “What is Cloud Computing?” http://searchcloudcomputing.techtarget.com/

Graphic Card – Endless Competition

What is graphic card? A graphic card can also be called as video adapter, graphics accelerator card, display adapter, or graphics card. Actually it is a hardware that converts the display signal from the motherboard to the monitor for display. The card is inserted onto the motherboard perpendicular to the board. For some motherboard, the Graphical chip (GPU) is embedded into the motherboard, while some would have a separate video card. Today let me talk about those separate video cards.

Structure

A video card is basically an electric circuit card with input and output ports. First, it has a chipset consisting of a Graphics Processing Unit, which is called as GPU. The GPU is the graphic accelerator which is dedicated to processing graphical information. The graphic card also has video BIOS. The BIOS is used to let the users control the settings of the video card, i.e. to communicate with the card. The BIOS also controls the card’s operation. Also, a graphical card consists of video memory. The video memory can be made up to 8 Gb nowadays. It is used to store the video information like the color, pixel…etc temporarily so as to facilitate the graphical process.

The card also has different ports for connecting to the monitor. For example,  the blue port is called the VGA port and is connected to the monitor. Now, there is a new and more commonly used port called the DVI port. It supports the HDMI output and thus is becoming more and more popular.

Development

Now, the computer development is fierce. Generally, the graphic cards are divided into 3 categories: the low-level cards, mid-level cards and the advanced cards and their prices vary accordingly. Actually the competition among companies in the advanced card category is the hottest one. To manufacture the stronger graphic cards, the companies employ different ways to enhance the performance of their graphic cards.

First, the companies compete in making their graphic card with the strongest GPU. As mentioned, the graphic cards have the chipset (GPU) determining their graphical performance, so the companies make the cards better by increasing the clock frequency which in turn determines the card’s ability to process graphical data. The video RAM is also another important factor to distinguish the “better” cards because it determines the resolution of the display. In a word, both GPU clock frequency and video RAM are “the more, the better”. However, the clock frequency cannot be elevated endlessly as the higher clock frequency will increase the operation temperature of the chipset. This poses a great problem to the engineers.

To tackle the problem, the graphic card companies have developed new technologies. For example, the Graphic card company nVidia developed the SLI (Scalable Link Interface) technology in which 2 display cards work in parallel to process the graphical data, so as to accelerate the graphical display performance but not with the expense of increasing the temperature. Another company ATi has also developed the similar technology called Crossfire. Today, The SLI and Crossfire technology are also not limited to 2 cards only. In fact, 3 or more cards are now able to be connected together to achieve ultimate graphical excellence.

Now, the display card has also progressed into multi-GPU technology. From 2 GPU per card to 4 and now even more, a single graphic card is becoming more capable in dealing with the graphical demanding games like Crysis 2.

In conclusion, the competition of different company in the aspect of video cards will keep going because people are demanding for better technologies and perfect graphic. Whenever there is a problem, there is alternatives to the problems. As  graphic card companies, they will keep working to earn more money. As consumers, we will not stop pursuing the better technologies. Therefore the computer world is always progressing!

Application of different shortest path algorithms in daily life

The shortest path problem is the problem of finding a path between two vertices (or nodes) in a graph such that the sum of the weights of its constituent edges is minimized. (Shortest path problem - Wikipedia, the free encyclopedia, 2011) In other words, when we have to find a path with minimum cost to go from a place to another place which there are a number of intermediate points in between to travel to with different costs, we are dealing with the shortest path problems. It should be noted that the phrase “shortest path” here does not necessarily mean physically shortest distance, but a path with minimum weight which can be measured in, say, time or  monetary cost.

Actually, the shortest path problems are closely related to our daily life. For example, we all have to travel within the campus when we attend different lectures, such as going from Meng Wah Complex (MW) to Main Building (MB) to attend the next lecture.
 

Graph 1: The map of the University of Hong Kong

In fact, we should wisely choose our path so we can travel with least amount of time in order to arrive on time, especially when the next lesson starts only 5 minutes later. This will be an example of shortest path problem and the weight will be the time cost. Certainly different routes will involve different buildings and pathways, which some are less time-consuming. For instance, we may go via Chong Yuet Ming Amenities Centre (CYA) and K K Leung Building (KK), or we may walk on the University Drive to Haking Wong Building (HW) first and pass through the podium of Kadoorie Biological Sciences Building (KBS) amd reach MB. However, there are many other possible routes and it is quite impossible for us to try out all possible route to find the one with least time needed. Therefore, we need a more effective method to find out such path and we may apply the Dijkstra’s algorithm to solve this problem.

Graph 2: A simplified map of the University of Hong Kong with checkpoint marked

The Dijkstra's algorithm is an algorithm that can find the shortest path for a single source graph. The Dijkstra's algorithm adopts the concept of greedy approach. First, we will have to initialize the temporary “estimated time needed” from the starting point (the source which is MW in this case) of every checkpoint in the University of Hong Kong (the node, e.g. CYA, MW, MB).
 
Obviously, the time needed to go to the starting point from the starting point is 0. However we do not know the time needed to go to other checkpoint from the starting point yet so we may take them as infinity. Then we can choose a checkpoint which take the minimum time to go from the starting point (choose any one if there are more than 1 checkpoint needed same minimum time to go to) and update the neighbouring checkpoints’ “estimated time needed”, i.e. if the time needed to go to next checkpoint(CPnext) via the chosen checkpoint(CPchosen) is less, we will go to CPnext via the CPchosen instead and replace the time needed to go to CPnext by the sum of the time needed to go to the CPchosen from starting point and the time needed to go to CPnext from CPchosen. And we repeat the above process until all checkpoints are considered.
 

 So, we know that the Dijkstra’s algorithm is useful in solving this kind of shortest path problem. Then can we apply the Dijkstra’s algorithm to every situation to solve the shortest path problems? Unfortunately, the answer is no. The Dijkstra’s algorithm will fail to find the path with minimum weight if the graph consist of some negative weight. At first glance, this situation seems impossible to happen as you may wonder since there will never be a path that will reduce the time needed for the journey. Yet, according to Robert Sedgewick, "Negative weights are not merely a mathematical curiosity; [...] [they] arise in a natural way when we reduce other problems to shortest-paths problems".(Sedgewick, 2003) (Bellman–Ford_algorithm - Wikipedia, the free encyclopedia, 2011) Besides, the weight need not to be time only. Consider the same situation that you have to go from a place to another in the University of Hong Kong, but you have to pay if you go through some place (e.g. the Run Run Shaw Podium (RR)) and some other place may pay you back instead (e.g. the Starbucks may be giving out free coffee at the Sun-Yat-Sen Place). For simplicity, we may consider go from MW to MB again. Consider you can make a handsome profit (e.g. +$1000) going only from the Main Library New Wing (LBN) to KK, but going from RR to LBN costs you a lot (e.g. -$300) and assume travelling in other checkpoint costs nothing . Then according to the Dijkstra’s algorithm, you will choose the LBN checkpoint at last since the only incoming check point is from RR to LBN which make lower the priority of LBN. And even if you update the neighboring checkpoint of LBN, the cost of MB cannot be changed since other checkpoints are all visited already. So the Dijkstra’s algorithm can not give an optimal solution. And we need another algorithm to deal with this kind of problems and we may apply another method -- the Bellman-Ford Algorithm.

“Bellman-Ford is in its basic structure very similar to Dijkstra's algorithm, but instead of greedily selecting the minimum-weight node not yet processed to relax, it simply relaxes all the edges, and does this |V | − 1 times, where |V | is the number of vertices in the graph” (Bellman–Ford_algorithm - Wikipedia, the free encyclopedia, 2011) This means that we will repeat the updating process of Dijkstra’s algorithm for each checkpoints instead of the neighboring checkpoints only, and repeat this for every checkpoints. This guarantees that every checkpoint is updated every time and promises the optimality of the path even if there are negative weights. Nonetheless, this will result in many repeated procedures (overlapping sub-problems) and we may apply the concept of Dynamic Programming in order to speed up the Bellman-Ford algorithm, i.e. using the previously updated checkpoints’ information to update the next checkpoint.

All in all, the shortest path problems is closely connected to our daily life. This is because many problems can be transformed into shortest path problems, though they may not seems to be shortest path problems at first glance, if we analyze the problems carefully. I think this lead to another observation - we should, in terms of both algorithm and problem solving skills, try to think in multiple-dimension and should not simply limited ourselves into 1 solution only. For example, there are different algorithms to solve the shortest path problems, such as the Dijkstra’s algorithm and Bellmen-ford algorithm covered in this survey and many other not discussed in this survey. However, different algorithms may have their own strengths and drawbacks (e.g. Dijkstra’s algorithm is faster and simpler but cannot deal with graph with negative weights) and we should not be constrained to use 1 only in all situation.

References

1. Shortest path problem - Wikipedia, the free encyclopedia. (2011, 9 23). Retrieved 9 28, 2011, from Wikipedia: http://en.wikipedia.org/wiki/Shortest_path_problem
2. Robert Sedgewick. Algorithms in Java. Third Edition. ISBN 0-201-36121-3. Section 21.7: Negative Edge Weights. http://safari.oreilly.com/0201361213/ch21lev1sec7
3. Bellman–Ford_algorithm - Wikipedia, the free encyclopedia. (2011, 9 23). Retrieved 10 4, 2011, from Wikipedia: http://en.wikipedia.org/wiki/Bellman–Ford_algorithm

Microblogging

Wong Kwan Ting

Introduction
Recent years, microblogging is very popular all over the world. Microblogging is a type of blogging, but it has a small scale than blogging. In a microblog, users are only allowed to post small content within 140 words or a photo only. Nowadays, it is more and more convenient to surf the Internet everywhere. People are able to connect to the Internet by their smart phones and they can update their microblogs no matter where they are. The most famous companies which provide microblogging services include Twitter, Weibo and Plurk.

History of Microblogging
The history of microblogs starts from 2005 and it was called tumblelogs at that time. It was a simpler type of blog which was a quick and good platform to publish people’s work on the Internet. After one year, the term “microblogs” was used by Twitter instead of “tumblelogs”. Then, more and more companies start to provide microblogging services and each of the providers has its own characteristics. For instance, Plurk has a timeline view which shows the statuses, photos and videos of the user in a form of timeline. This helps people share information and news more quickly and efficiently. Due to the fast development of the sharing platforms on the Internet, the Internet has become a place where breaking news and new ideas come out. The news and ideas can usually spread all over the world after a short period of time.

Benefits of Microblogging to the Business
The main characteristic of microblogging is the function “follow”. The microblog users are able to follow other users so that the most updated statuses or photos are pushed to the followers’ news feeds. The followers are able to choose what updates they want to get. Moreover, as microblogs are mainly public to all people, microblogging is a very good platform to promote business. Because of the popularity of microblogging, a lot of corporations, such as Dell, Apple and Microsoft, have microblogs on Twitter or other microblogging service providers to deliver their exclusive news or most updated products and services to the public. For instance, Microsoft posted a video of the new Xbox Live Experience on their Twitter recently. The video is just like an advertisement or a TV commercial on the Internet but it is totally free of charge. The companies do not need to pay a cent to publicize their products and services on the microblogs. The microblogs are also good places for marketing and public relations. The Sysomos study reveals that the group of marketers is more active than general users on Twitter. 15% of the marketers follow more than 2000 people but only 0.29% of the general users follow more than 2000 people. [1] Apart from companies, the film stars and singers from Hong Kong, Taiwan and the mainland China are very common to use Weibo to share their daily life to their fans. Through microblogs, the stars are able to promote their recent work. Furthermore, they can build up a good image to their fans and the public. This could help them attract more opportunities on working. Hence, microblogging is also a great and convenient promotion platform to the public figures.

Privacy and Security on Microblogging
Apart from the benefits that microblogging brings, there are some issues which we need to aware. For instance, privacy is a main concern on microblogging. The users of microblogs may post some personal information such as telephone numbers or addresses on their microblogs. As their microblogs may be seen by the public, the personal information may spread at a very fast rate. Moreover, it is not secure even if the users set up privacy on their microblogs. For instance, Google’s Buzz platform automatically publicizing their users’ email contacts as followers in 2010. [2] This aroused a controversy to the users and Google later edited the settings. Besides, hackers may have access to the server of the microblogging service providers and steal the users’ information. As a result, the users of microblogs should not rely on the providers very much and they should be careful before posting their personal information on their microblogs.

Freedom of Speech on Microblogging
The freedom of speech on the microblogs is also a concern on society. This issue mainly affects the users of microblogs in the mainland China, especially the users of Weibo. For instance, Weibo would filter the posts or photos which are related to the June Fourth Incident or sensitive information considering the Chinese government. The Internet should be a platform which allows every one expressing their opinions and ideas freely. The action of deleting statuses is very annoying to the users since they are not allowed to express what they are thinking. This matter leads to a controversy to the microblog users and the microblogging service providers. It is also a new social issue to society in Hong Kong and the mainland China.

Conclusion
In conclusion, microblogging help us spread our ideas and the news to the world more quickly. More and more people are able to exchange their information via microblogs. Nonetheless, the convenience may lead to some side-effects. The privacy and security of microblogs are still doubtful to the users. Furthermore, freedom of speech on microblogs also leads to a controversy on society in recent years. We should identity the benefits and demerits of microblogging and think twice on how we use microblogs.

References

1. Inside Twitter: An In-depth Look Inside the Twitter World. Sysomos; 2009-06-10. Retrieved 2009-06-23.
2. Google Buzz redesigned after privacy complaints. The Telegraph (London); February 15, 2010. Retrieved March 25, 2010.