http://dspace.dtu.ac.in:8080/jspui/handle/123456789/83 2026-04-28T04:03:54Z 2026-04-28T04:03:54Z DINKAR, NAIK KISHOR http://dspace.dtu.ac.in:8080/jspui/handle/repository/14831 2016-06-06T05:52:29Z 2016-05-01T00:00:00Z

Title: DESIGN AND ANALYSIS OF SINGLE MODE SINGLE POLARIZATION PHOTONIC CRYSTAL FIBER Authors: DINKAR, NAIK KISHOR Abstract: Photonic Crystal fibers consisting of defect region at a center surrounded by multiple air holes running along its length have been the topic of most interest of researchers because of unique properties over conventional optical fibers. Here basics of Photonic Crystal Fibers, PCFs modeling methods are discussed. A rectangular core photonic crystal fiber structure has been designed based on higher order mode filtering, in which single polarization is obtained with asymmetric design and introducing different loss for x-polarization and ypolarization of fundamental mode. Single polarization single mode operation of a highly birefringent photonic crystal fiber is investigated in detail by using a full vector finite element method with anisotropic perfectly matched layer. The variations of confinement loss and effective mode area of x-polarization and y-polarization of fundamental mode have been simulated by varying the structural parameters of the proposed photonic crystal fiber. At optimized parameters, the confinement loss and effective mode area is obtained as 0.94 dB/m and 60.67 μm2 for x-polarization as well as 26.67 dB/m and 67.23 μm2 for y-polarization of fundamental mode respectively at 1.55 μm. Therefore, 0.75 m length of fiber will be sufficient to get x-polarized fundamental mode with effective mode area as large as 60.67 μm2.

2016-05-01T00:00:00Z VERMA, PANKAJ http://dspace.dtu.ac.in:8080/jspui/handle/repository/13960 2014-12-19T11:12:22Z 2012-01-27T00:00:00Z

Title: PERFORMANCE ANALYSIS OF FIXED AND MOBILE WIMAX SYSTEMS Authors: VERMA, PANKAJ Abstract: The common feature of the next generation of wireless communications technologies (or 4G ) will be the convergence of different wireless networks with multimedia services such as speech, audio, video, image, Internet services, and data at high data rates and with high mobility, high capacity and high QoS. There are many techniques that fulfill these requirements. One of the most important technique is Orthogonal Frequency Division Multiplexing (OFDM) . OFDM has recently gained a lot of attention and is a potential candidate for 4G wireless systems because it promises data rates up to one Gbps or less under stationary conditions and up to about 100 Mbps under vehicular conditions and it has robustness against multipath fading channels effects. A variation of OFDM is Multi-Carrier Code Division Multiple Access (MC-CDMA) which is an OFDM technique where the individual data symbols are spread using a spreading code in the frequency domain. The spreading code associated with MC-CDMA provides multiple access technique as well as interference suppression. WiMAX (Worldwide Interoperability for Microwave Access) is OFDM-based technology that supports point to multi-point (PMP) Broadband Wireless Access (BWA) for the next generation radio access. Main application (fixed and mobile) of WiMAX today is for MAN/WAN base stations and link stations. It delivers the maximum range (50 km) and higher data rates (up to 75 Mbps) than Wi-Fi. WiMAX has been implemented depending on IEEE 802.16 standard which was designed by Institute of Electrical and Electronic Engineers (IEEE). This thesis aims to analyze and simulate a MC-CDMA system to be used in WiMAX instead of OFDM system. A MATLAB code had been written to simulate both Fixed WiMAX (IEEE 802.16d) and Mobile WiMAX (IEEE 802.16e). The analysis part includes a comparison between them in performance evaluation. The simulation results include the performance analysis based on bit error rate (BER) versus bit energy to noise rate (Eb/No ) plots and spectral efficiency of different modulation and channel coding schemes according to the standard IEEE 802.16. The results show that MC-CDMA outperforms OFDM in WiMAX system and enhances the performance more when spreading factor increases. Description: M.TECH

2012-01-27T00:00:00Z RAGHA, N S SENTHIL, KUMAR http://dspace.dtu.ac.in:8080/jspui/handle/repository/13569 2014-12-19T11:02:35Z 2006-01-24T00:00:00Z

Title: IMAGE PROCESSING FOR SYNTHSIZING LUNG NODULES: A EXPERIMENTAL STUDY Authors: RAGHA, N S; SENTHIL, KUMAR Abstract: The aim of this experiment is to study how effectively image processing utilises in CT scan. So a software application is developed using MATLAB software to experiment computer tomography (CT) image, using this application we identify the real nodule and create a 3d mesh Gaussian structure. A Certain parameters of this 3D mesh are taken to create a synthetic lung nodule. This synthetic nodule is inserted into the CT image. The real and synthetic nodules are evaluated from its appearance and shape in the CT image and 3D mesh plot. Based on this, more number of synthetic nodules can be created using various parameters; the characteristics of nodules are stored in to single database, which might be useful to the radiologist for further references of analysing the Lung nodules. Description: ME THESIS

2006-01-24T00:00:00Z DUBEY, NISHANT http://dspace.dtu.ac.in:8080/jspui/handle/repository/13475 2014-12-19T11:00:07Z 2006-01-31T00:00:00Z

Title: PERFORMANCE ANALYSIS OF OPTICAL CDMA & WDMA FOR BROADCAST LAN'S Authors: DUBEY, NISHANT Description: ME THESIS

2006-01-31T00:00:00Z