Why bother with a Literature Survey? How do you do it? Here are some
motivation, tips and samples.
Room-level indoor localization is a hot new technology that can be applied in
many areas. We found three popular methods for applying it.
This method was developed by the University of Cambridge AT&T Computer Laboratory in 1997. It uses radio-synchronized ultrasound instead of infrared and provides a higher level of precision. However, Active Bat infrastructure is costly both to purchase and to install.
This method was developed by Nissanka B. Priyantha, Anit Chakraborty, and Hari Balakrishnan in 2000. It emphasizes a lack of dependence on a centralized structure to implement a complete positioning system. Cricket requires the purchase and installation of special beacons and receivers.
This method was developed by Gaetano Borriello, Alan Liu, Tony Offer, Christopher Palistrant and Richard Sharp in 2005. It is a unique mixture of other schemes. For example, it uses existing technology to reduce costs (like Place Lab and Radar); it decentralizes for the purpose of maintaining privacy (like Cricket and GPS); it uses human-inaudible ultrasound (like Cricket and Active Bat); and it provides room-level precision (like Active Badge). The strengths of WALRUS are: no specialized and costly hardware is needed; room level precision, since ultrasound detection is accurate nearly 100% of the time when used within 10m of the server beacon; and well suited for non-interactive awareness in devices that move at human speeds.
Other methods also exist, but they are either for outdoor localization or are unsuitable for what we want to do.
Here is a chart by Gaetano Borriello et al.  comparing with different methods of indoor localization.
Figure 1 - Summary of location sensing systems by Gaetano Borriello 
For our final year project we combined the features of WALRUS, Active Bat and Cricket to come up with a new technology for room-level localization. In particular, we used the concept of human-inaudible ultrasound.
Herecast is a Location-Based WiFi Services application created by Mark Paciga in September 2003 . It started as his MSc project at the University of Western Ontario (UWO). It uses WiFi signals to locate the position of users, and it uses the information for social purposes, such as a friend-finder and a location-based message board. Herecastís map covers the area of UWO, but the resolution is such that precision is limited only to buildings or large areas. As a result, the position of users is not very precise. In our design, we aim to locate users with a precision of 2-3 meters.
1.3.2 Global Positioning System (GPS) based applications
The most popular wireless location-based technology is the Global Positioning
System (GPS) . Most cars use this technology to guide their way, while Loopt
 uses it to provide a social network services, such as finding friends and
sharing information about buddies. However GPS has its drawback, the reliability
drops when it is used indoors, as the GPS signals have difficulty penetrating
building walls. Ted Morgan, CEO of Skyhook, said the location system is more
accurate than global positioning systems that use satellites to find locations,
saying "GPS was designed by the military for guiding missiles," he said. "It
performs poorly in urban areas where buildings block the view of satellites, and
it doesn't provide any coverage inside of buildings." 
With enough access points, Wi-Fi based applications can work smoothly both indoors and outdoors. The benefit of using Wi-Fi is much more significant in Hong Kong since Hong Kong has an increasing number of Wi-Fi access points. Also, the high density of concrete buildings makes Hong Kong one of the best places to adopt this technology.
1.3.3 Google Latitude
Google Latitude is a location-aware mobile application developed by Google. It uses signal from cell tower as a source to estimate the userís current location. It allows a mobile phone user to track him or her and track other users where he/she is in the Google map. Although the system knows the location of the user, the user can protect the privacy by selecting whether his or her information and location would be shown to the others. 
Since the coverage of cell tower is really huge, therefore the location estimation of Google map may result with an error tolerance of 100m. The user may find it not precise enough if he or she really want to find other frineds using this Google application.
Role-playing games (RPGs) are a branch of video games in which players typically have various attributes centering on one or more personalities (ďavatarsĒ) who possess specific skills and determine the outcome of the story. One of the attractive features of RPGs is that each playerís attributes are clearly displayed in form of numeric values, instead of simply an abstract graphical representation.
Figure 1.3.1 - Old RPG in Unix OS
The first generation of RPGs began in the mid-1970s. At that time, RPGs were written at a university and mainly Unix-based and text-based. In 1980, Dungeons and Dragons (D&D) was released, and it became the most popular RPG for a few years. Starting in 1988 with Pool of Radiance, SSI Company produced a series of RPGs based on the D&Dís rules. This led to in the success of some other famous RPG games such as Dragon Quest and Final Fantasy.
In the mid 1990s, gamers saw the next major revolution in RPGs. The RPG market demanded higher quality and features, and players became hard to satisfy. Therefore RPGs were created with longer playing times, more complicated quests, better audio, and full-motion videos. Final Fantasy VII was one of the most popular games developed by SQUARE. It was released in 1997 for Sony's PlayStation and in 1998 for Microsoft's Windows-based personal computers. With brand-new graphics, outstanding music, and colorful scenery, as of December 2005, the game had sold more than 9.8 million copies worldwide.
Figure 1.3 - Final Fantasy (RPG) running on a PDA
In the early 21st century, thousands of game companies have been expanding their business to the mobile device market, and numerous famous RPGs now run on PDA and mobile phones.
1.3.2 PDA games
A mobile game is a video game played on a mobile phone, smartphone, PDA or handheld computer. Simply speaking, a PDA game is a game that can be executed on a PDA platform.
The first famous game to be pre-installed onto a mobile phone was Snake on selected Nokia models in 1997. The Snack series has became the most-played videogame in the world, with over a billion people having played the game.
Nowadays, PDA Games are mainly sold through game company networks. By surfing the Internet, we found lots of different PDA games:
Figure 1.3.2 - A typical PDA game on the Internet
Typically, PDA games are classified into 7 categories: Action, Action-adventure, Adventure, Role-playing, Strategy, Simulation, Others. Action games are the easiest to find online, while Role Playing Games (RPGs) are the most popular.
Fig 1.3.3 - Pie chart showing the distribution of game categories in 2005 (whole game market)
Figure 1.3.4 - A common PDA game
The graphics used in PDA games varies from simple 2D graphics to complex 3D-graphics.
Figure - 1.3.5 - a game with 3D graphics
Although many PDA games are available online in the market, they may not meet the demands of todayís gamers, who are looking for surprises and excitement; we believe that a good RPG could easily become popular. If you study the RPGs available online today, you will find that most are not PDA-oriented. Also, most of them only include fighting scenes and ignore one main advantage of a PDA, a touch screen and stylus.
Therefore, we think we have found a niche, and we aimed to create a RPG that will make us to be pioneers in this new field.
Copyright HKUST CSE Dept. 2015