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PublicationOverview of chameleon mechanism in B-MAC protocol for WSN(Learning and Library Sciences (LLS), 2020-12-15)
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PublicationPerformance study of a MIMO mobile terminal with upto 18 elements operating in the sub-6 GHz 5G band with user hand(IEEE, 2020-01)This paper investigates the performance variation when a different number of antenna elements (AEs) is integrated onto a single MIMO mobile terminal, both in free space and when held in a user hand in data mode. Starting with a minimum of two AEs, this investigation assessed the performance of the MIMO terminal with every additional two AEs (up to 18 AEs) in terms of envelope correlation coefficient (ECC), efficiency, multiplexing efficiency, capacity and maximal ratio combining (MRC). The integrated MIMO antennas are identical and operate between 5 and 6 GHz for 5G applications. Results indicated that ECC increased with the number of AEs. However, ECC remains less than 0.32 for the case of 18 AEs in both free space and with a user hand. Meanwhile, the free space efficiency of about 90 % for the two AEs is observed to decrease with the increasing number of AEs to about 50 % with 18 AEs. However, the efficiency of elements changes with user hand depending on the level of interaction between each element and the hand. Direct blockage of AEs by the hand resulted in efficiencies of as low as 5 %, while at the same time, other AEs retained an efficiency of up to 75 %. At the center frequency of 5.5 GHz, the free space capacity is 11.1, 49.5 and 83.2 bit/s/Hz with two, ten and 18 AEs, respectively. However, the use of the mobile terminal in the proximity of the user hand degraded these levels by 11 % (two AEs), 35 % (10 AEs) and 31 % (18 AEs). Finally, multiplexing efficiency showed that capacity degradation is caused mainly by the degradation of AEs efficiency, whereas the impact of low correlation between AEs is found to be an insignificant factor. In addition to the capacity analysis, gain and diversity gain of the maximal ratio combining technique was also investigated.
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PublicationLocal neighbourhood image properties for exposure region determination method in nonuniform illumination images(IEEE, 2020-04)During image acquisition, nonuniform illumination regions are produced due to several factors, such as improper environment lighting and inappropriate capturing device setting. Applying contrast enhancement methods with the same enhancement concept to the whole image can over enhance or under enhance nonuniform illumination image. Thus, different and specific enhancement concepts should be applied to different regions in nonuniform illumination image. This concept requires identification of those different regions. Almost all existing methods that introduced the region determination process can only detect two different regions, namely, dark and bright, which inadequately represent the real exposure condition because the methods only consider intensity criteria to determine the regions. For this problem, a new method used for the accurate detection of nonuniform illumination regions is proposed. Different illumination levels affect not only the intensity but also the details in an image. Thus, three image attributes, namely, intensity, entropy and contrast, which are evaluated locally in detecting the regions, must be considered. For the detection to be on par with that in humans, the three attributes are combined with a rule-based method for the identification of illumination regions. Experimental results involving evaluation from research experts demonstrate that the proposed method qualitatively detects different illumination regions (i.e., over-exposed, well-exposed and under-exposed) in a nonuniform illumination image more accurate than the state-of-the-art methods.
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PublicationAn Augmented Reality (AR) marker-based application for smart campus: UniMAP residential college(Institute of Advanced Scientific Research, 2020)Augmented Reality nowadays is getting wide usage with all application in human daily life. This paper of research is about the design and development of Augmented Reality (AR) for smart campus urbanization using the student’s residential college. The technique used in this application is marker-based. Then analyze the efficiency of positioning the object on the right place on display screen with the image processing to get the tag from the image and set as the image marker. The image triggered is analyze either it is projected on the image or slightly change from the actual position. The scope of this research is direct and specific as it will help newcomers or visitor to the hostel area to get information and direction easily with this application. There are many area and information inside as the users should know with the guidance of the application. This research is to make an Android-based application with the interfaces of Augmented Reality to demonstrate and testify the proficiency of virtual data and information shown on the device screen and the feasibility of the augmented object plotted and registered at certain places of hostel. Thus, by using this AR technology to enhance user experience in the hostel area with direction and right information instantly. The contribution of this research trying to reach were those first-time visitors when they arrived at the hostel as there is lack of information for them to locate themselves in such a large campus area and assisting them especially in the term of information and directions. Information is easier and capable to receive by the user as they require only a smart phone to operate the advance feature from the AR application. Furthermore, it does not need any of internet connection in order to use the application and can be operated in offline. With the specified and unique images, users are able to view the virtual object in an entertaining AR environment at the same time better presentation of info can also be delivered.
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PublicationDual-band, dual-sense textile antenna with AMC backing for localization using GPS and WBAN/WLAN(IEEE, 2020)A wearable textile antenna with dual-band and dual-sense characteristics is presented in this work. It operates at the 2.45 GHz band for WBAN and WLAN applications, and at the 1.575 GHz band for Global Positioning System (GPS) applications. An antenna backing based on an artificial magnetic conductor (AMC) plane operating at 2.45 GHz band is introduced to reduce the backward radiation and to improve antenna gain. It consists of a 3×3 array of square patch unit cells, where each unit cell is integrated with four square slits and a square ring. A square-shaped patch is then located on top of the substrate as its radiator. To enable dual-band operation, two corners of this radiator are truncated, with each of the four corners incorporated with a rectangular slit to enable its circular polarization characteristic in the GPS band. Simulation and experimental results are in good agreement and indicate proper antenna operation with linear polarization in the 2.45 GHz band and circular polarization in the 1.575 GHz band, with realized gain of 1.94 dBi and 1.98 dBic, respectively.
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