Performance Evaluation of Mobile U-Navigation based on GPS/WLAN Hybridization

This paper present our mobile u-navigation system. This approach utilizes hybridization of wireless local area network and Global Positioning System internal sensor which to receive signal strength from access point and the same time retrieve Global Navigation System Satellite signal. This positioning information will be switched based on type of environment in order to ensure the ubiquity of positioning system. Finally we present our results to illustrate the performance of the localization system for an indoor/ outdoor environment set-up.Comment: Journal of Convergence Information Technology(JCIT

ROLAX: LOCATION DETERMINATION TECHNIQUES IN 4G NETWORKS

In this dissertation, ROLAX location determination system in 4G networks is presented. ROLAX provides two primary solutions for the location determination in the 4G networks. First, it provides techniques to detect the error-prone wireless conditions in geometric approaches of Time of Arrival (ToA) and Time Difference of Arrival (TDoA). ROLAX provides techniques for a Mobile Station (MS) to determine the Dominant Line-of-Sight Path (DLP) condition given the measurements of the downlink signals from the Base Station (BS). Second, robust RF fingerprinting techniques for the 4G networks are designed. The causes for the signal measurement variation are identified, and the system is designed taking those into account, leading to a significant improvement in accuracy. ROLAX is organized in two phases: offline and online phases. During the offline phase, the radiomap is constructed by wardriving. In order to provide the portability of the techniques, standard radio measurements such as Received Signal Strength Indication (RSSI) and Carrier to Interference Noise Ratio(CINR) are used in constructing the radiomap. During the online phase, a MS performs the DLP condition test for each BS it can observe. If the number of the BSs under DLP is small, the MS attempts to determine its location by using the RF fingerprinting. In ROLAX, the DLP condition is determined from the RSSI, CINR, and RTD (Round Trip Delay) measurements. Features generated from the RSSI difference between two antennas of the MS were also used. The features, including the variance, the level crossing rate, the correlation between the RSSI and RTD, and Kullback-Leibler Divergence, were successfully used in detecting the DLP condition. We note that, compared to using a single feature, appropriately combined multiple features lead to a very accurate DLP condition detection. A number of pattern matching techniques are evaluated for the purpose of the DLP condition detection. Artificial neural networks, instance-based learning, and Rotation Forest are particularly used in the DLP detection. When the Rotation Forest is used, a detection accuracy of 94.8\% was achieved in the live 4G networks. It has been noted that features designed in the DLP detection can be useful in the RF fingerprinting. In ROLAX, in addition to the DLP detection features, mean of RSSI and mean of CINR are used to create unique RF fingerprints. ROLAX RF fingerprinting techniques include: (1) a number of gridding techniques, including overlapped gridding; (2) an automatic radiomap generation technique by the Delaunay triangulation-based interpolation; (3) the filtering of measurements based upon the power-capture relationship between BSs; and (4) algorithms dealing with the missing data. In this work, software was developed using the interfaces provided by Beceem/Broadcom chip-set based software. Signals were collected from both the home network (MAXWell 4G network) and the foreign network (Clear 4G network). By combining the techniques in ROLAX, a distance error in the order of 4 meters was achieved in the live 4G networks

HORUS: A WLAN-BASED INDOOR LOCATION DETERMINATION SYSTEM

As ubiquitous computing becomes more popular, the need for context-aware applications increases. The context of an application refers to the information that is part of its operating environment. Typically this includes information such as location, activity of people, and the state of other devices. Algorithms and techniques that allow an application to be aware of the location of a device on a map of the environment are a prerequisite for many of these applications. Many systems over the years have tackled the problem of determining and tracking user position. Examples include GPS, wide-area cellular-based systems, infraredbased systems, magnetic tracking systems, various computer vision systems, physical contact systems, and radio frequency (RF) based systems. Of these, the class of RF-based systems that use an underlying wireless data network, such as the IEEE 802.11 wireless network, to estimate user location has gained attention recently, especially for indoor applications. RF-based techniques provide more ubiquitous coverage than other indoor location determination systems and do not require additional hardware for user location determination, thereby enhancing the value of the wireless data network. However, using a wireless network for location determination has the challenge of dealing with the noisy characteristics of the wireless channel. Current location determination techniques for the 802.11 wireless networks suffer from these noisy characteristics, leading to coarse grained accuracy. A key feature of current techniques is the dependence on building a radio map for the area of interest and using this radio map to infer the user location. Using the radio map to infer the user location is a computationally intensive process and may consume the scarce energy resource of the mobile units. The Horus system is concerned with developing accurate methods for determining the user location with low computation requirements. Our goal is to build a location determination system that is capable of determining the user position with high accuracy, is light enough to be implemented on energy-constrained devices such as handheld computers, and is scalable to track a large number of users and to be used with large areas. We identify different causes of the wireless channel variations and we develop techniques to handle these variations. The results show that the Horus system is able to achieve accuracy significantly better than the current WLAN location determination systems. Moreover, the number of operations required to run the algorithm is better than the current systems with more than an order of magnitude

Investigation of Microscopic Structures in the Low-Energy Electric Dipole Response of 120Sn using Consistent Experimental and Theoretical Observables and Digital Signal Processing for Nuclear Physics Experiments

This thesis consists of two parts which deal with the low-energy electric dipole response (LEDR) of atomic nuclei and the development and commissioning of a digital data acquisition system for nuclear-structure experiments, respectively. A term commonly found in the literature for the overall LEDR of atomic nuclei is Pygmy Dipole Resonance (PDR), which was historically used to imply the picture of a neutron-skin oscillation. Since the underlying mechanisms in the LEDR region have been found to be diverse, the term PDR was avoided within this thesis, unless referring explicitly to a neutron-skin oscillation. Part I tries to uncover the generating nuclear-structure features at play in the LEDR of 120Sn below the neutron-separation threshold via two complementary experiments and their theoretical comprehension. The conducted 120Sn(a,a'g) and 119Sn(d,pg) experiments are presented and nuclear-structure calculations performed within the Quasiparticle-Phonon-Model (QPM) are introduced, together with two corresponding reaction-theory approaches. The alpha-scattering experiment was performed at the Research Center for Nuclear Physics in Osaka, Japan, utilizing the combined particle and gamma-ray spectrometer setup CAGRA+GR. Experimental results indicate the presence of isoscalar excitations with a surface-mode character in the LEDR of 120Sn, resembling a neutron-skin oscillation. The 119Sn(d,pg) transfer experiment was performed with the SONIC@HORUS setup at the University of Cologne and constitutes a novel tool to study the microscopic character of individual LEDR states. The remarkable agreement between theoretically obtained (d,pg) cross sections and the experimental data allows to benchmark the predictive power of the QPM and therein employed Energy-Density-Functional calculations. Furthermore, the QPM reproduces the key structural aspects of the LEDR in 120Sn suggested by previous experiments, including the summed B(E1) strength and a transition to more complex configurations at higher excitation energies. It was enforced that theory and experiment are consistently compared via identical observables and striking agreement is found for several experimentally accessible values on a quantitative level. The microscopic information, obtained for the first time in this thesis, complements the knowledge on the relevant nuclear-structure phenomena present in the LEDR of 120Sn. Part II covers a state-of-the-art digital data acquisition system which was designed and commissioned within this thesis. The flexible system exhibits significantly reduced dead time and reaches excellent energy resolution for gamma-ray spectroscopy. It fully replaces the predecessor system and is suitable for all nuclear-physics experiments performed today and in the near future at the 10 MV FN-Tandem accelerator laboratory of the University of Cologne

Intelligent Indoor Parking

Nowadays positioning based navigation is an integrated part of our everyday’s routine. Hence, it is hard to succeed without a GPS based navigation system in a bigger city today. However, indoor positioning and navigation are still in their infancy, although these services would be desirable in many areas. One obvious application domain is vehicle navigation in a parking garage. The use of an indoor vehicle navigation system is convenient for the drivers, decreases the unnecessary circling in the garage and reduces air pollution. In this paper, we introduce our iParking indoor positioning and navigation system which has been under development. Our system monitors the occupancy of the parking lots, and with the aid of a Wi-Fi based background wireless infrastructure tracks the position of the vehicle entering the parking garage and navigates the driver to an appropriate free parking lot. Lot selection is handled at the entry point of the garage based on simple preferences, eg., the closest disabled parking space. The navigation interface is the driver’s smartphone. Currently, we have been implementing a prototype of our iParking system in a parking garage of a shopping mall for demonstration purposes