Overview of positioning system

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INTRODUCTION

Definition of a localization system

There has been an explosion of technologies to communicate with wireless devices. The global positioning system (GPS), radio frequency (RFID), wireless network (Wi-Fi), mobile phone using global system for mobile communications (GSM) and many more technologies have helped mankind in different fields such as military services, aeronautical teams, security systems and in the lives of common people. For example, the army using GPS to locate their deployed soldiers, the control tower communicating with pilot of an airplane through RFID, different security systems can be connected using Wi-Fi signals and people using the mobile phone to communicate.

Munoz, D et al. (2009) defines position location as that of finding or estimating the location, in a two-dimensional (2D) or three-dimensional (3D) space, of a point of interest within a coordinate system constructed using some known references. On the other hand Schiller, J, Voisard, A (2004) claim that the term location-based services (LBS) is a recent concept that denotes applications integrating geographic location (i.e., spatial coordinates) with the general notion of services. Thus a localization system can be thought as a system that uses wireless network as a tool to detect the signal a mobile device, measure its signal strength, and use this data to locate the position of the device. A person using a positioning system can locate his car, laptop, personal digital assistant (PDA), and any other colleagues or friends using devices equipped with those types of wireless network. Surrounded by a dynamic environment, localization systems need to deliver information in real time. For instance a control tower must have the position of all airplanes in its coverage region to instruct which one is going to land the first.

Outdoor and indoor localization systems

Localization can be classified in two types, mainly outdoor and indoor.

Outdoor localization uses the satellite-based system to estimate the position of wireless devices. Logically, outdoor localization covers a broader area than indoor. For outdoor tracking of devices, the global positioning system (GPS) has become the most popular as it can give valuable position information. For instance tourists use the GPS to find the nearby hotel or to find their way in an alien country. Or the police tracking an escaped prisoner through his mobile phone by means of the GPS. But outdoor localization also pertain some challenges like GPS satellites can be occluded by buildings and trees. Because of these problems, vision has become another important sensor which is widely used. Nevertheless, vision can be affected by illumination changes. This depends mainly on outdoor environments such as sun clouds and other climatic changes.

Due to the different barriers and obstacles present in indoor location, accurate and reliable indoor positioning system has become a challenge for developers. Indoor areas are more complex and they consist of walls, chairs, tables, etc that affect the estimation of localized devices. Moreover, we have dynamic situations such as persons moving around the building and interference coming from wired and wireless network. The indoor positioning systems usually make use of a map to give the absolute or relative position of the device. Many wireless technologies have been used to develop indoor positioning systems and there has always been a trade off between quality and price. Some systems developed for indoor positioning are namely Optotrak system, Active Bat positioning system, WhereNet's Real Time Locating System and Online Person Tracking system.

Types of wireless networks used

Wireless networks solve the problem of space limitation through wireless connections between different devices situated long distances apart. Mobile phones for example use wireless network for easy and fluid communication. They are increasing considerably and can be categorized into three types, namely wireless personal area network (WPAN), wireless local area network (WLAN) and wireless wide area network (WWAN).

WPAN is a wireless computer network that uses computer devices such as telephones and PDA's for communication. Personal network can also provide privacy to its users. The range of a personal area network is quite short, typically about 10 m. Figure 1.1.3(a). shows a WPAN through which a personal computer, PDA, printer and digital camera has been connected.

WLAN connect two or more computers without the help of cables or wires. Hence users from other interconnected computers can share and view files, and also share resources such as printers. Most of the time, WLAN are confined to a single building or a group of buildings. But one WLAN can be connected to another WLAN which is far apart via telephone lines or radio waves.

The use of mobile telecommunication cellular technologies makes WWAN more comfortable to use. WWAN offers 3G, GSM and general packet radio service (GPRS) services though the internet. WWAN are often connected through satellites or the telephone network. The speed on most wireless networks are typically 1-108 Mbit/s, which is relatively slow compared to wired networks.

Wi-Fi

In 1996, an Australian research body, the Commonwealth Scientific and Industrial Research Organization (CSIRO) obtained the patent behind Wi-Fi, the IEEE 802.11 standard. Devices like MP3 player, video game consoles, PDAs are becoming Wi-Fi enabled products. A typical Wi-Fi antenna (802.11b or 802.11g) might have an indoor and outdoor range of 32 m and 95 m respectively, but these values can vary depending on the strength of the signal generated.

Infrared

The infrared (IR) has frequency of about 3*1012 Hz. For IR to work properly it needs a line-of-sight between the transmitter and the receiver and a little interference from other sources like fluorescent light and sunlight can affect the reception of the signal. IR has been well anchored in our society as it is used devices such as mobile phones, remote controls, TVs, laptops, etc.

Bluetooth

Bluetooth is slowly replacing IR ports in devices such as mobile phones and laptops. It is a low-cost and low-power technology and offers a range of 100 m for communication. Bluetooth does not need a line-of-sight for transmission but a dynamic changing environment can affect its signal.

Radio frequency

Using radio frequency (RF), radio frequency identification (RFID) has a wavelength of 1 to 3 metres. RFID uses radio frequency circuit and electromagnetic transmission to store data. It is often used in complex indoor environment as radio signals can travel through walls and human bodies easily. Hence RFID technology offers a broader range for communication of wireless devices.

Applications using positioning systems

Positioning systems are gaining popularity in this era of technology. Many applications have been devised to offer adaptive and convenient services such as the location of persons and their devices at different places as home and office.

One scenario can be an application used for someone working or being a member in a fitness centre. The application will consist of the days per week that the person has to go to the centre for exercising. So when the person enters the centre, the application will automatically detect the mobile device of the user, for example his PDA, and will show him a map of the fitness centre along with his position in the building. The application will measuring his weight and guide the user to which activities he has to practice. The above data will be stored on a database. The application can also advice the user which weight of dumbbell to choose. If the user is running on a threadmill the application automatically detects his position and monitors his heart rate during running. If necessary, the service can also adjust the running speed to which the user can afford.

Another scene can be that a person enters a large building like a museum. So using the position location, the person gets a map of the building together with his location. At the start itself, the user can pay his entrance fee via access to his bank account through the application. He can also locate the different places of interest available in the museum and according to his taste he can be guided all around the building. The application can also display the picture of the object at that specific place and give necessary information like when the object was discovered and why is this object s precious. When the user gets out of the museum, the application automatically detects the device being out of range and the application automatically turns off.

An application can also be developed for tourists in Mauritius. Using wireless networks, the application can give details of the island like the history of Mauritius and its places of interest. It will also situate the user on a map. With respect to the users taste, pricing, etc the system will show him the different restaurants available. The application can also guide the user through the shortest route possible and estimate the time of arrival as the user moves towards his destination. Services like online booking of hotels can also be incorporated in the system.

WIRELESS TECHNOLOGIES FOR POSITIONING SYSTEMS

With the large availability of wireless network types like Wi-Fi, Bluetooth, infrared, ultrasound and radio frequency, different technologies are using one or combinations of wireless network to offer a more precise result of localization.

Ekahau

The Ekahau positioning system uses existing Wi-Fi set-ups. It detects the position of its targets based on the received signal strength indication (RSSI) values of the transmitted RF signals captured at different access points (APs). Ekahau has an accuracy of 1 m if there is a minimum of three overlapping APs. The system can simultaneously track thousands of devices. The tag is reasonably small with a weight of 48g and battery life time of 5 years. Ekahau is flexible and inexpensive for indoor localization.

Firefly

The Firefly system is a high level accuracy system of about 3 mm precision using IR signals. The program has a sampling rate of 30 scans per second for an amount of 30 tags being tracked. The location is tracked using a high-speed and real-time way with measurement delay of 3 ms. Even if the tags are small, they are uncomfortable due to the fact that cables are use for their connections. The Firefly is a system which is easy to install and maintain. A Firefly system with one tag controller and 32 tags cost around $27500.

Active Bat

The Active Bat system offers a 3D positioning system. A tag is carried by a person and receivers are placed on the ceiling. The Active Bat system uses ultrasound to locate the tags by measuring the time of arrival (TOA). The tags are small and convenient to carry and it is powered by a battery that can last around 15 months. But for a coverage area of 1000 m2, 720 receivers need to be fixed on the ceiling. However the Active Bat system can track 3 tags at the same time and provides an accuracy of about 3 cm for 95% of measurements.

PROBLEM DEFINITION

In this project, a system will be designed and implemented such as to locate the position of a person through his mobile device. One of the most important characteristics of the system is that it should be developed for mobile devices which will use wireless networks or communication.

For position location, we have many techniques like fingerprinting. Kolodziej, K. W, Hjelm,J (2006) explains that fingerprinting (scene analysis) technique examines a scene such as a room from a fixed vantage point. Radar measures signal strengths of mobile devices from the vantage point of a fixed base station. These measurements are then used to calculate the position of the devices on a two-dimensional coordinate system local to the building. Other writers suggest fingerprinting as follows. A map of the coverage area of the network is obtained by measuring received signal strength (RSS) at various points and using a propagation model for the entire area. After this, when a node needs to be localized, the RSS from it can help locate the area in which it is found with certain accuracy by comparing the current RSS levels with those stored from fingerprinting procedures (Munoz, D et al. 2009).

Fingerprinting is in fact a method used for position location. It gives the position of the mobile device by determining what is the signal received at every grid point inside a building. The grid points are in fact small areas inside the building. This technique uses the access points and the triangulation technique. Fingerprinting accounts for effects like reflection, attenuation and multipath, that the building, objects and people are going to have on the received signal. With respect to all the access points available, a site survey collects information and identifies each grid points. This will give a detailed description of the signal received on the floor of the building. But for identifying these grids, first we have to determine the signal received using a WLAN management system. This will give a signal structure database of the location map which will be used to track the position of the mobile device.

MOTIVATIONS FOR THE PROJECT

The University Of Mauritius has an area of about 5 hectares. It consists of different buildings blocks and a well set-up area with different services available. The University Of Mauritius has set up different Wi-Fi access points on the campus. This helps the students to get free internet access for the research work as long as they are in the available range. Thus with the availability of different Wi-Fi access points in strategic positions, the development of a system for localizing different mobile devices using this wireless technology is now possible. For instance, we have an access point in the Raiz Plaza building and in the cafeteria. The development of a localization system will be of great help to people who are unfamiliar with the university campus. It will be easier to locate people easily thus reducing time and facilitating the tasks of everyone on the campus.

DETAILED OBJECTIVES OF THE PROJECT

The project needs to satisfy the following objectives:

  • Access points need to be configured.
  • To set-up different wireless access points so as to cover the region of interest.
  • The access points have to be set-up in such a way that they can be intersected.
  • The network signal characteristics of the access points have to be measured.
  • A relationship has to be found between the wireless access points signal strength and position location.
  • A location map of the set-up access points have to be designed.
  • A system has to be designed and implemented to measure signal strength and deduce its position on the location map.
  • Relevant data concerning the strength of the signals received at different positions have to be collected.
  • The system (program) should be able to run on a laptop for mobility reasons.

PROJECT PLAN

BACKGROUND STUDY

WIRELESS LAN

Computers connected through wireless connection form a wireless LAN (a wireless network). A wireless network allows for device mobility and increase convenience for users. For network detection and communication, the computers must receive a signal strength which comes from an emitter. The emitter can be an access point. The above mentioned signal strength is known as the received signal strength (RSS).

Received signal strength (RSS)

Received signal strength is the signal captured by the receiver (laptop, PDA, computer) through a software for detecting and measuring the signal received at a specific location. If more than one signal is being emitted, the software should identify all the received signals at that specific point and measure the signal strength. The signal strength received decreases with distance of separation from the receiver and the emitter. The strength of the signal captured is used to identify the position of the mobile device with respect to a map. There are two techniques used for locating the device receiving the signal, namely time of arrival (TOA) and angle of arrival (AOA).

The amount of signal attenuation in the atmosphere which occurs due to effects like reflection, diffraction and scattering is known as the path loss (PL). It is the difference between the transmitted signal and the received signal.

The path exponent (n) depends mostly on the frequency and obstacles present in the environment. It is the rate at which the path loss increases with distance. An estimation of the path exponent for different environment are as follow:

  • 2 for open free space.
  • >2 where obstacles are present.
  • 3.5 for an indoor office.
  • 3.7 to 4.0 for a dense commercial or industrial environment.
  • 4.5 for a dense home environment.

The standard deviation of shadow fading (s) is the measure of the signal strength variability. It considers for effects of attenuation due to obstructions, orientation problems between transmitters and receivers and multipath that are not considered in the path loss.

PL = PL1 metre + 10 log (dn) + s

PL = total path loss experienced between sender and receiver (in dB).

PL1 metre = reference path loss (in dB) for the frequency used when the distance separating the transmitter and the receiver is 1 metre.

d = distance of separation between transmitter and receiver.

n = path loss exponent for the environment.

s = the standard deviation present in relation to the degree of shadows fading present in the environment (in dB).

Time of arrival (TOA)

Time of arrival measures the time difference between the emitter and the receiver to estimate the distance separating the two devices. The devices must have high clock synchronization to obtain an accurate time intervals between the sent signal and the received signal. Since the signal travels with velocity of approximately 3 x 108 ms-1, the distance of the separation between the transmitter and the receiver can be found using the formula:

D = c x t

D = distance in metres.

c = speed of propagation ~ 3 x 10 ms-1.

t = time in seconds.

Angle of arrival (AOA)

This techniques consists of a measuring the angle at which the signal is received from the emitter. The relative angles can the obtained by using antenna arrays to measure the phase difference of the signal as it reaches each element array. The accuracy in the AOA is affected by the number of sensors in the array and the distance separating the sensors.

In the diagram below, ?A and ?B are the angle of incidence of the received signal for receiver A and B respectively. The intersection of these two lines give the position of the emitter X.

Tri-lateration Technique

The tri-lateration technique makes use of three access points (emitters) to localize a mobile device (receiver). The amount of time required for a message to travel from access point A, B and C can be measured in tA, tB, tC. Given that the waves travel at a propagation velocity of 3 x 10 ms-1, we can calculate the distance DA, DB, DC from each of these access points (emitters) to the mobile device (receiver). These distances form a circular region around each transmitter A, B and C. The intersection of the three radii gives the position of the mobile device (receiver X) as shown in figure 2.1.1.1.1(a). The tri-lateration technique can also be used to localize a device using the received signal strength value.

Range of transmission

According to the Federal Communications Commission, the wireless signals are label in the 802.11 code. The 802.11 is further categorized in 802.11a, 802.11b, 802.11n, etc, according to their frequency generated and the range of transmission. Table 2.1.2(a) shows some typical Wi-fi signal range.

Degradation of Wi-Fi signals over distance

Wi-Fi signals loose signal strength as they propagate through air and as they encounter natural and manmade obstacles. This reduction in signal strength during transmission is known as attenuation. The problem of degradation of signal strength increases when interference is present. Attenuation grows exponentially as range increases. Due to excessive attenuation, the network's throughput will decrease. This is because operations occur at a low data rate and we need additional overhead to retransmit the frames. If the attenuation is too high, the user can also loose connection to the network. "You represent attenuation in decibels (dB), which is ten times the logarithm of the signal power at a particular input divided by the signal power at an output of a specified medium" as from Wi-Fi planet website. Hence if an obstacle decreases the propagation of the signal from a power level of 400 milliwatts input to 200 milliwatts output, we obtain an attenuation of 3dB. Here are the attenuations for some typical obstacles in table 2.1.3(a).

Attenuation = 10 x log ( signal power input / signal power output )

WIRELESS ACCESS POINTS

Wikipedia defines a wireless access point as a device that allows wireless networked computers to be connected through wireless connections such as Bluetooth or Wi-Fi. An access point can be a radio transmitter or receiver. These radio waves travel at different frequencies which can range from 2.4 GHz to 5 GHz. You need to be in the transmission range and to have a transmitter/receiver (PC wireless card) so as to receive the signal from the access points. Two access points should not be broadcasted on the same channel as they compete and cancel each other. Hence they would be become unusable.

Wi-Fi hotspots

Wikipedia defines a hotspot as a physical location that offers internet access over a wireless LAN through the use of a shared internet connection and a single router. From this location, u can access internet through your mobile, PDA, laptop, cell phone or through any other device that has wireless connection. Places like coffee shop, bars, colleges, health clubs or hotel can charge users or offer free access to WLAN. For a charged Wi-Fi hotspot, the network must be restricted. Thus the user needs to be authenticated before gaining access to a paid hotspot, while for a free hotspot no authentication is necessary.

Types of access points

Stand alone access points

The stand alone access points are designed for home or small office networks (SOHO). These access points together with the network are easy to manage as they consist of a small number of access points. The stand alone access points can be used for a WPAN.

Light weight access points with central controller

This type of access points consist of a central controller (that can be an Ethernet switch) and can control a large number of access points. The access points are normally light weight and thin and can be used for a WLAN. The central controller is very expensive and thus light weight access points are only used by large enterprises.

Virtual management

Virtual management has been developed by mixing the light weight access point and stand alone access point principles. They can function on their own and can detect and connect to other networks access point so as to provide higher voice and video quality. The virtual management work as fat access points, meaning that if one of the access point stops working the network is still available.

Netgear

Netgear is a United States company that manufactures computer hardware and computer networks. It was founded in 1996. Netgear products can be found in North America, Europe, Middle East, Africa and Asia Pacific areas and has developed a range of wireless products.

Some features of Netgear wireless products:

ADSL2+ VOICE GATEWAY WITH 802.11G WIRELESS DVG834G:

  • Wireless speeds: 802.11g in 2.4 GHz band.
  • USB 2.0 host and 2 analog phone lines.
  • Size: 223 x 153 x 31 mm.
  • Weight: 0.5kg.
  • Input power: 18W.
  • Adapter: 12V DC, 1.5A.
  • Standards: CE, UL, FCC 15, A-TICK, C-TICK, Wi-Fi.
  • ADSL, LAN, Internet, USB, Wireless.
  • Security: Intrusion logging and reporting.
  • Operating system: Microsoft Windows Vista, XP, 2000.
  • Wireless speeds: 802.11b (max 11Mbps), 802.11g (max 54 Mbps), 802.11n (max 300 Mbps).
  • Size: 177.5 x 130 x 31 mm.
  • Weight: 0.265kg.
  • Input power: 18W.
  • Adapter: 12V DC, 1.0A.
  • Standards: IEEE 802.11n draft 2.0 specification, 802.11b, 802.11g, 2.4 GHz.
  • Security: Intrusion detection and prevention, denial-of-service attack prevention, double firewall.
  • Operating system: Microsoft Windows Vista, XP, 2000.

RANGEMAX™ WIRELESS-N ROUTER WITH BUILT-IN DSL MODEM DG834N:

  • Size: 225.5 x 172 x 39 mm.
  • Weight: 0.56kg.
  • Standards: IEEE 802.11n draft 2.0 specification, 802.11b, 802.11g, 2.4 GHz.
  • Security: Intrusion detection and prevention, denial-of-service attack prevention, double firewall.
  • Operating system: Microsoft Windows ME, XP, 2000, Mac OS, UNIX, Linux.

ANALYZING RELATED WORKS ON FINGERPRINTING

ENHANCED INDOOR LOCATING IN A CONGESTED WI-FI ENVIRONMENT

Assumptions

During the experiment, the assumptions made were that:

  • Access points are set up outside the building and also on the 1st and 2nd floor of the building.
  • The building is a congested Wi-Fi environment as there is a total of 16 access points.
  • The main target is the 2nd floor with a coverage area of approximately 60mx15m.
  • The access points have been thoroughly positioned so as to cover a maximum area of the building (2nd floor).
  • There was a testing phase and a training phase.
  • Fingerprinting was the technique used in this experiment.

Methods used

Naïve Bayes classifier

It is based on the Bayes theorem with a naïve independence assumption. It is used to find the location Lx by having the fingerprint of different access points. This method is based on probability by taking into consideration the existence of a set of access points. Signal strength is ignored.

Given AP = (AP1,...APn), the joint probability of Lx and AP is:

P (Lx, AP1,...,APn) = P (Lx) P (AP1,...,APn|Lx)

= P (Lx) P (AP1|Lx) P (AP2|Lx, AP1)... P (APn|Lx, AP1,..., APn-1)

= P (Lx) P (AP1|Lx) P (AP2|Lx)... P (APn|Lx)

= P (Lx) ?i=1

Support vector machine

We use the support vector machine (SVM) to arrange data in groups. These data consist of a target value and some features. Thus when given the attributes, the SVM will use a model to estimate the target value. The SVM results can be affected by signal fluctuations and will hence reduce the accuracy.

K-nearest neighbor

This is an algorithm used for finding the position of an object based on the results of its nearest neighboring access points only by measuring the value of the signal strength. The K-nearest neighbor will use the fingerprinting values from the database to estimate the location of an object. This algorithm uses only the value of the signal strength to perform its calculations. The K-nearest neighbor algorithm provides enough accuracy but due to signal strength variation of the same position for indoor location, there can be some measurement error.

Redpin algorithm

The Redpin algorithm makes use of a mixture of Vector distance and the similarity between access points to find the most appropriate location. This algorithm uses the number of common access points, the number of non-common access points and the signal strength value to find the data which is closest to the fingerprinting values.

Correlation between locations and access points

In one location, the visibility of the access points are not always the same. This is due to some environmental effects that causes the Wi-Fi signal to vary with time. The Point-wise mutual information (PMI) is used to calculate the correlation between one access point and one location. The PMI is calculated using the formula:

I (Lock ; APi) = log (P (Lock , APi) / (P (Lock) P (APi)))

The higher the value of I (Lock ; APi), the closely is the location associated with the access point.

Noise filter

The noise filter is used to remove those access points that are the least visible in the fingerprints of a location. The most visible access points are called "relevant AP" and the least visible ones are taken as noise and are thus ignored. Hence using a noise filter for a location will only select those access points that are the most frequently detected and ignore the remaining ones. The noise filter is given by the formula:

Experiment environment and apparatus

In this experiment, we will use a WLAN of 802.11b which consist of seven 3-COM access points and six Motorola access points. For the collection of the fingerprints, the Nokia N95 has been used as it has built-in Wi-Fi for 802.11b and 802.11g. Access points are located on both the first and the second floor of the building, but our main target is the second floor. The latter has a size of approximately 60 m x 15 m. Moreover we have three access points that are found outside the building but will be detected during the experimental phase. This makes the building a congested Wi-Fi environment. The red dots in the figure 3.1.3(b) shows the position where the access points are placed.

This experiment was performed for a period of seven days for nine rooms from the second floor. More than 100 fingerprints were collected from each room and there was 1002 unique fingerprints that were obtained. The distribution for the fingerprint results are as shown in table 3.1.3(a).

The 10-fold cross validation has been used to define the accuracy of the experiment. The algorithms used for the experiment are:

  • Naïve Bayes classifier
  • Support vector machine
  • K-nearest neighbor
  • Redpin
  • Enhanced Redpin

Results

It has been found that Naïve Bayes has the least accuracy followed by SVM and KNN which have nearly the same accuracy. Then we have the Redpin, and the Enhanced Redpin with 87% accuracy.

From the experiment, it has also been noted that the most appropriate value of k for KNN, Redpin and Enhanced Redpin is k=5.

Granularity of Rooms

The rooms have been combined with their neighboring rooms to create a larger virtual room. This has shown that the level of accuracy increases with the increase in adjacent rooms. With a combination of four adjacent rooms, the accuracy of the algorithms can be up to 90%.

Noise Filter

The noise filter was applied to the training data. The result was that the accuracy of all the algorithms was improved except the Naïve Bayes. This is because nearly all the noises have been filtered out. Moreover, the PMI had no effect for the Redpin (k=5).

Number of APs

The also found that as the number of APs increased, the accuracy of the location also increased. But this was only for the number of APs ranging from 1 to 10. As the number of APs gets more than 10, there is fingerprinting pollution from APs with less frequency visibility. This reduces the accuracy and causes confusion for the fingerprint matching.

ANALYSIS OF LANGUAGES

This section is for analyzing the available languages that can be used for the design of the system. Three languages that are mostly used these days are mostly Java, VB.NET and C++.

SELECTION OF LANGUAGES

After a through analysis of the advantages and disadvantages offered by all the languages named above, Java has been found to be the most appropriate one. It provides for many features that makes it better over VB.NET and C++ for this software development; namely:

  • Java is simple. Therefore it is easier to learn, write, compile and debug compared to C++ and VB.NET. Java provides for automatic memory allocation and garbage collection.
  • Java is platform independent. Java codes can be written and debugged on one computer and moved and run on other computers. Java allows the same program to be run on different systems. Java is platform independent at source and binary levels.
  • Java is object-oriented. Java allows for creation and manipulation of objects. These objects can be made to work together and thus java allows you to create modular programs and reusable codes.
  • Security was considered when designing java. The java compiler, interpreter and runtime environment were developed with a level of security.
  • Java is robust. This is because java focuses a lot on error checking and error handling. The java compiler detects lots of errors that can crop up during its execution in other languages. Hence java is much reliable than other languages.
  • Java is interpreted. To run java programs, we need an interpreter. This interpreter will convert the program into bytecode. Hence any machine which has a java interpreter can run the bytecodes and execute the program.
  • Java is multithreaded. Java allows the execution of several tasks simultaneously within a program. Multithreading is necessary for visual and network programming.

ANALYSIS OF DATABASES

There exist many database models for the storage and manipulation of data. The most common ones have to be selected and considered.

Oracle Database

Oracle database is a product of the Oracle Corporation. Oracle database is a relational database management system and allows data redundancy and data replication. It also stores the data and executes functions and procedures. Oracle database is becoming more and more popular as it handles enterprise database with great efficiency.

Microsoft SQL Server

Microsoft made a database, namely Microsoft SQL Server which uses T-SQL and ANSI SQL as query languages. Microsoft SQL is a relational model database server. It allows for XML query also.

MySQL

MySQl is ones of the most popular databases as it run efficiently with fewer resources than other databases need. Moreover it is an open-source, thus free database server. MySQL, being a relational database management system provides for multi-user access.

PostgreSQL

Like many others, PostgreSQL is another free and open source database. It is an object-relational database management system. PostgreSQL is known for its stability and reliability. It is extensible and is Windows and Linux compatible also.

Microsoft Office Access

Microsoft Office Access is a relational database management system. It has a fairly good and easy graphical user interface and can connect data from other sources such as XML, Excel, text, Outlook and HTML.

SELECTION OF DATABASES

Among the above mentioned databases, we have to choose one that allows easy management of the data. Operations such as insert, retrieve and modify will be performed. This database will contain about hundred data which is relatively small compared to large enterprise databases. Thus, PostgreSQL has been chosen to be the ideal database for the possessing of the system.

OUTDOOR EXPERIMENT ON FINGERPRINTING

Experiment 1

Aim: The aim of this experiment is to measure and analyze how received signal strength (RSS) varies with distance in an outdoor atmosphere.

Apparatus: Laptop, Wi-Fi router, measuring tape, electric wire extension.

Procedure:

  1. The router has been configured and placed in an open space as shown in the diagram below.
  2. 5 angles of 45 degrees are measured from the router as sown in the diagram. The angles are named Sample 1, Sample 2, Sample 3, Sample 4 and Sample 5.
  3. Starting with 1 angle from the router, measure intervals of 5 metres and record a range of the Received Signal Strength (RSS) at each distance.
  4. Calculate the Median from the range of RSS and plot a graph from the medians obtained.
  5. Repeat steps 3 and 4 for the remaining 4 angles.
  6. Plot as graph from the average of the medians.

Assumptions:

  1. We assumed that the effect of the wind is negligible in the variation of the RSS.
  2. During the experiment we found that the sun may have some effects on the value of the Received Signal Strength. Hence we noted the sun and shadow values.
  3. Interference of people in the environment was not considered.

Experiment 2

Aim: The aim of this experiment is to measure and analyze how received signal strength (RSS) varies with distance in an outdoor atmosphere when the router is placed in an indoor environment.

Apparatus: Laptop, Wi-Fi router, measuring tape, electric wire extension.

Procedure:

  1. The router has been configured and placed inside a building as shown in the diagram below.
  2. 3 angles of 45 degrees are measured from the router as sown in the diagram. The angles are named Sample 1, Sample 2 and Sample 3.
  3. Starting with 1 angle from the router, measure intervals of 5 metres and record a range of the Received Signal Strength (RSS) at each distance.
  4. Calculate the Median from the range of RSS.
  5. Repeat steps 3 and 4 for the remaining 4 angles.

Assumptions:

  1. We assumed that the effect of the wind and sun are negligible in the variation of the RSS.
  2. Interference of people in the environment was not considered.

REQUIREMENT SPECIFICATION OF THE SYSTEM

This document will give clear and precise functionalities of the system. Any constraint present in the system must also be defined. If any of the requirements is wrongly defined, this will make us to work in a wrong direction when implementing the system. Thus, this step needs to be thoroughly implemented.

The system requirements can be broken into two sections, namely functional and non-functional requirements.

Functional Requirements

Functional requirements are the statements of services that the system should provide. Functional requirements will give detailed description on the main functionalities of the system. It will also describe how the system is going to react and behave to particular situations.

The functional requirements of the system are as follows:

  • The system interface should consist of a space box to allow the user to enter the RSSI values for the different APs.
  • The system interface should contain 5 space boxes for the RSSI input values of the 5 APs.
  • The system interface must display a map of the floor where the system will be used.
  • The system must be able to compute the position of the user from the RSSI values input for the 5 APs.
  • The system interface should display the user location on the map.
  • The map must be divided into grids for locating the position of the user.
  • The map should show the different position where the access points have been set up.
  • The system interface should consist of a space box where the position location of the user can be entered.
  • The system must compute the RSSI values of the 5 APs from the input of the position location.
  • The system interface must output the 5 RSSI values obtained from the values of the input position.
  • The system must contain a database that will store the fingerprinting values of the system.
  • The system interface must be connected to the system database.
  • The system must be operational as from the time the system have been started and stopped.

Non- Functional Requirements

Non-functional requirements are the constraints on the services or functions that are expected to be present on the system.

The non-functional requirements are:

  1. Usability Requirements
    • The system should be easy to use and to learn.
    • The system interface should be appealing to users.
    • Attractive colours causing eye strain should be avoided.
    • The system interface must not be overloaded with buttons and data.
  2. Efficiency Requirements
    1. Performance Requirements

MOTION GRAPHICS

An overview on motion graphics

Definition of motion graphics

Wikipedia defines motion graphics as the graphics that use video and/or animation technology to create an illusion of motion or a transforming appearance. Motion graphics hence brings a life to static contents. Audio can be added to give a much deeper meaning to the data presented. For example a dynamic web page or the welcome page of a software is more pleasing than a static one. Long ago we were using the frame-by-frame technique to make animations. With the evolution of technologies, computers have become enough powerful to calculate the change in the picture and hence it gives the illusion of motion. Software like Adobe After Effects and Apple Motion are used to give a dynamic touch to the images.

Short history on motion graphics

Motion graphics began to appear in the early 1800 by the animator John Whitney. He started first with some presentations and then in 1960, then founded a company known as the Motion Graphics Inc. Saul Bass is considered to be the leader in the development of animated graphic design. He gave a new turn in the progress of motion graphics and worked in the title sequence of some films such as "The Man With The Golden Arm", "Anatomy of a Murder", and many others.

SYSTEM DESGN

OUR METHODOLOGY

After we have analyzed the architectures of the previously mentioned algorithms and methods we are going to use the most appropriate ones. We are going to use a Wi-Fi router for the propagation of Wi-Fi signal in an indoor environment. Many such studies have been made on the indoor localization using Wi-Fi signals. The designing system will consist of the following features:

Accuracy: The nearest-neighbour (NN) algorithm will be used along with the fingerprinting technique for the indoor localization. The system can have an accuracy of 3 metres radius.

Convenience: The system will make use of Wi-Fi technology which is widely being used nowadays.

Cost: The system cost is not extremely expensive in relation to the service provided.

The system will comprise of a robust infrastructure for the computerized localization. Wi-Fi routers of 802.11b will be set up at specific places in order as to have full coverage of the building. A Wi-Fi enabled device will then be used to find and display the latter's approximate position. The fingerprinting technique will be used for the device localization.

DESCRIPTION OF THE SYSTEM

The system will consist of an interface that will allow the user to input the RSSI values of different access points and determine the location of the device, or allows the user to input the position location of the device and the system will determine the RSSI values of the different access points. The system will have a map which will consist of grids that will divide the map into different locations.

There will be a testing phase where access points will be placed at strategic positions inside the building. After detecting the router, the RSSI values of each grid will be measured using an RSSI measuring software. These values will then be inserted and saved into a database. Hence after that the user has input the data, the system will look for the results in the database and display them to the user.

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