Статьи журнала - International Journal of Wireless and Microwave Technologies
Все статьи: 532
Статья научная
Negative impedance converter (NIC) circuits are very interesting and beneficial building blocks with the capability of generating negative resistance, capacitance and/or inductance elements which do not exist as a singular electrical component in practice. They are commonly used for the impedance matching and parasitic element cancellation in electrically small antennas and amplifier circuits. In this study, a special kind of NIC circuit in HF band up to 30 MHz is analysed, designed and physically realised with a current feedback (CFB) operational amplifier (OPAMP) which is the core active element of the NIC circuit. The non-inverting terminal of CFB OPAMP is used for RF input signal with the elimination of DC offset voltage in the proposed NIC circuit. The negative impedance conversion capability of the circuit is theoretically proved and simulated first. This capability of CFB OPAMP to generate negative impedance is very important in high-frequency applications as they have low distortion and faster switching than that of voltage feedback (VFB) OPAMP. For the physical realizations, printed circuit board (PCB) is designed and manufactured on FR-4 dielectric material. Measurement results obtained from the realized circuit with resistive (100Ω) and capacitive (10pF) loads to be converted negatively showed that the negative impedance conversion performance of the circuit is very close to its theoretical behaviour in the lower HF frequencies generally in 3- 20 MHz band.
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Analytical Model for Wireless Channel of Vehicle-to-Vehicle Communications
Статья научная
Vehicle-to-Vehicle (V2V) communication system is a network of vehicles that communicate with each other to exchange information. The environment between vehicles affect in the signals that travel from the transmitter to the receiver, subsequently, it is important to comprehend the underlying characteristics propagation channels. This paper discusses and models some of the key metrics such as path loss, power delay profile, and delay spread at 5.2 GHz carrier frequency. The analyses are presented for two scenarios; both of the transmitter and receiver are stationary and in moving case with considering the direction of the moving and the separation between the vehicles. Likewise, a probability of a presence of some impediments in between of the vehicles with various separations is considered. The achieved results show that path loss for many types of environments may be predicted with using the presented model channel Model and location of the obstacles is sensitive to the received signals.
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Статья научная
One of the business activities in the company is Inventory management. Stocktaking is an important process to ensure stable operation. A conventional method for item identification is through an attached human-readable label. Employees use an inventory sheet of paper to keep track of items. We propose new system inventory management based on an android application to increase time efficiency for Obtain data tracking through NFC (Near Field Communication) tag-based system. This approach involved 11 participants who performed stocktaking to compare performance between the new and old systems. We collect 54 of the Sample data for time evaluation using a t-test to analyze the data. The result was significantly shorter time in stocktaking process of new system than conventional method (df = 26, t = -7.075, p < .001). Furthermore, the proposed system could be a viable solution for reduce the time needed to complete the stocktaking process in the company.
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Статья научная
Artificial Neural Networks have been widely used in security and privacy domains for alleviating the issues of malicious attacks. Several embedded codes like Visual Basic for Application Macros are reasonably powerful scripts that can help to automate iterative processes in word processing documents. It has been observed that, unethical hackers exploit these embedded scripts for their malicious intents. Since most of the Microsoft Word users are unaware of such malicious attacks because they are layman end users and mistakenly considers less suspicious contents. And therefore, these hackers prefer to use Microsoft Office documents as most vulnerable items for or Attack vectors. As a general approach, non-executable files are assumed to be less vulnerable than executable files. This implies that these document files could provide an easy and convenient exploitable pathway that can allow hackers to execute their intended malicious actions on the victim’s machine. This research paper presents an automatic detection of malicious embedded codes in general and Microsoft Office documents as a specific case for experimental analysis. This research paper considered only malicious behavior of the embedded codes i.e. checks the status of inclusion or exclusion of the executable code. The malicious datasets are developed to create a knowledgebase where documents are pre-processed. Thereafter the data sets are disassembled using reverse engineering and then malicious features are extracted from the documents. In this research paper, nineteen different malicious keys were extracted. Later, feature reduction technique was applied. Based upon actions; these malicious keys were reduced to eight behaviors. Finally, a machine is trained using artificial neural network with eight input features; extracted from individual disassembled scripts. Afterwards, output nodes that represent malicious or benign behavior classify the existence of attack i.e. exists or does not exists. Based on the training model, a total of seven hundred ninety-two samples of documents were tested. Finally, the research has achieved an average accuracy of 92.2% in the identification of maliciousness of embedded codes in Microsoft Office documents as a case. This result shows that the proposed system has high accuracy in detecting malicious Embedded in word processing documents.
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Application of Digital Mockup Technology
Статья научная
Digital simulation design is one of the mechanical product modern design methods. We have introduced the concept and meaning of digital mockup technology in mechanical design and its architecture, design cycle, which are concerned multi-domain UML, multi-body dynamics and multidisciplinary design. We also have analyzed the automobile digital simulation design method and digital mockup technology.
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Статья
This paper analyzes and researches the theories of the encryption communications and identities authentication over the Internet banking based on the PKI technology. Combined with the specific Internet banking system, this research tries to design Internet banking system communication encryption and identities verification and the workflow and main functions. Implementing application to enhance confidentiality of the information transferred by the network communication, this research solves the problems of encrypting Internet banking data and verifying the identities of users and Internet banking. Finally, this paper explores the key technology more in-depth in the designing.
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Applications of Leaky-wave Antennas: A Review
Статья научная
This review discusses some of the widely used applications of Leaky-wave antennas (LWA) along with their certain types. LWAs have been used extensively in various fields since their origin in the 1940s. They provide wide range of applications that include radars, human sensors, imaging and satellite communication. These antennas have advantage of frequency scanning in a single sweep which make them better choice for frequency scanning applications. Different techniques are integrated with them which increase their importance by providing ease of fabrication and low-profile system. In addition to discussing different types of LWA, this paper contains a comparative analysis of these types which helps in providing a clear knowledge of how and where these antennas can be used. Most of the antenna parameters have a tradeoff between gain and radiation patter, for which careful evaluation of these parameters is needed to make a choice for antenna. Slight modification in the antenna renders great increase in its performance or sometimes degrade it as well. LWA are used for 5G applications which is the latest trend and has great potential of development in coming years. Recent advances in LWA put emphasis on attaining radiations at the broadside which is a challenge for them. The challenges and possible future directions which can draw from existing data have been briefly discussed in this review. To form this review, 15 papers from last 6 years are considered which discusses various parameters of these antennas like radiation pattern, directivity and their fabrication complexities.
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Approaches of Buried Object Detection Technology
Статья научная
This paper describes the different art of buried object detection technology and algorithms. This detection of buried object finds application in many areas, importantly in the Landmine detection which is of growing concern due to the danger of buried landmines to people’s lives, economic growth and development. This paper describes and analyzes different technology available. The approaches discussed are Electrical Impedance Tomography, X-ray backscatter, Infrared Systems, Acoustics/seismic systems; Neutron based Method and finally Ground-Penetrating Radar with two commonly available approaches: Least squares and SVD approach. Finally, the paper concludes highlighting the need to improve the way this information is processed and compared.
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Area Limitations on Smart Grid Computer Networks
Статья научная
Smart grid implementations rely on the real-time monitoring and controlling of the electric power grid. To achieve real time there is need for a messaging system with minimum delays. After mentioning latest implementations and their delays we analyze the role of the different communication protocols needed within smart grids and we describe key factors to a message's delay. Taking into consideration a packet's speed constraints we then calculate a radius, within which, the ETSI communication requirements for smart grids are satisfied.
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Attacks on Cyber Physical System: Comprehensive Review and Challenges
Статья научная
CPS is often comprised of several networked systems that could really observe as well as modify real-world objects and operations. They're analogous with IoT systems, and that therefore CPS concentrates mostly on interplay of mechanical, communications, as well as compute operations. As a result of their connection with IoT, a truly innovative CPS element, the “Internet of Cyber-Physical Things (IoCPT)”, has been established. The speedy pace and substantial development of CPS does have a consequence upon several parts of people's lives and permits a plethora of services and applications, including such e-Health, home automation, and e-Commerce. Interlinking the physical and virtual realms, on the other hand, poses additional security risks. As a necessary consequence, CPS cyber-security increasingly piqued the interest of both academics as well as corporations. In this research work, a literature review has been undergone in terms of cyber security in cyber physical systems. All the literature papers on cyber security have been collected from standard journals like IEEE, Springer and Elsevier. The collected papers are analyzed in diverse aspects like application, dataset used, technique utilized, tool and performance recorded. Finally, the research gaps identified is manifested to guide the future researchers on intrusion detection in CPS.
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BER Analysis with Adaptive Modulation Coding in MIMO-OFDM for WiMAX using GNU Radio
Статья научная
This paper explores how MIMO increases channel capacity and how the fundamental characteristics of a MIMO system can create significant test challenges. Spatial modulation (SM) is the latest developed modulation method in the field of communication. The latest research on this shows that SM is useful to achieve the multiplexing gain for the single antenna system, this avoids the inter-channel interference but the spatial modulation is inherently unable to get transmit-diversity. In other words, SM is a novel modulation technique which combines the high multiplexing gain provided by the spatial modulation and transmit-diversity gain, given by the space time block codes (STBCs) technology. Different space-time block coding (STBC) schemes including Alamouti’s STBC for 2 transmit antennas as well as orthogonal STBC (OSTBC) for 3 and 4 transmit antennas are explored. The result of using these MIMO techniques is higher data rate or longer transmit range without requiring additional bandwidth or transmit power. This paper presents a detailed study of diversity coding for MIMO systems. In addition, adaptive modulation and coding (AMC) technique in conjunction with MIMO techniques constitute a technological breakthrough that greatly helps in satisfying the ever increasing demands of wireless networks. This paper presents a performance study of Mobile WiMAX networks based on MIMO and AMC perspectives. It also describes how to implement WiMAX PHY with MIMO on software defined radio (SDR) experimental setup with the help of USRP N210 as hardware and GNU Radio as software platforms.
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Статья научная
Free Space Optics is a medium with high bandwidth which has maximum data rate. Demand for large data speed capacity has been increasing exponentially due to the massive spread of internet services. So with the growing transmission rate and demand in the field of optical communication, the electronic regeneration has become more expensive. With the introduction of power optical amplifiers the cost of converting optical signals to electronic signals has been brought down immensely. This research paper describes the effect of varying duty cycle on BER performance of the FSO link with hybrid amplifier having different attenuation.
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Статья научная
In this paper, the bit error rate (BER) performance of SFBC-OFDM systems for frequency selective fading channels is observed for various antenna orientations and modulation schemes. The objective is to find out a suitable configuration with minimum number of receiving antenna that requires minimum signal power level at the receiver to provide reliable voice and video communication. We have considered both M-ary phase shift keying (MPSK) and M-ary quadrature amplitude modulation (MQAM) in the performance analysis considering both perfect and imperfect channel state information (CSI). The authors have expressed the BER under imperfect channel estimation condition as a function of BER under perfect channel condition in this paper. The finding shows, for a BTS with 4 transmitting antenna and MS with 2 receiving antenna BPSK performs better for both perfect and imperfect CSI. Maximum permissible channel estimation error increases with the usage of more receiving antenna at the expense of increased cost.
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Big Data Compression in Mobile and Pervasive Computing
Статья научная
The usability of Mobile devices and portable computers has been increased very rapidly. The main focus of modern research is to handle the big data in Mobile and pervasive computing. This paper gives an overview of Mobile Data Challenge which was a smart phone based research done by Nokia through Lausanne Data Collection Campaign. The Mobile Data Challenge was introduced when the amount of mobile data was seen to be increased very much in a short period of time. The rise of big data demands that this data can be accessed from everywhere and anytime. For handling such a huge amount of data e.g. SMS, images, videos etc, this data must be compressed for easy transmission over the network. It also helps in reducing the storage requirements. There are various techniques for the compression of data that are discussed in this paper. SMAZ and ShortBWT techniques are used to compress SMS. JPEG and Anamorphic Stretch Transform are used to compress the images.
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Статья научная
In the recent development of the Internet of Things (IoT), Artificial Intelligence (AI) plays a significant role in enabling cognitive IoT applications. Among popular IoT applications, location-based services are considered one of the primary applications where the real-time location of a moving object is estimated. In recent works, AI-based techniques have been investigated to the indoor localization problem, showing significant advantages over deterministic and probabilistic algorithms used for indoor localization. This paper presents a feasibility study of using Bluetooth Low Energy (BLE) and Feed Forward Neural Networks (FFNN) for indoor localization applications. The signal strength values received from thirteen different BLE ibeacon nodes placed in an indoor environment were trained using a Feed-Forward Neural Network (FFNN). The FFNN was tested under other hyper-parameter conditions. The prediction model provides reasonably good accuracy in classifying the correct zone of 86% when batch size is 100 under the learning rate of 0.01.Hence the FFNN could be used to implement on location-based IoT applications.
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Статья научная
A Wireless Network is an assortment of organization hubs that can work with framework or Adhoc mode. Because of the absence of incorporated control in Adhoc-based remote organizations, planning a steering convention to give a proficient and appropriate technique to course the information with fewer clogs, bundle drop has turned into a difficult issue in remote organizations. The significant goal of the present review is to foster a Load Aware Congestion Control. The further developed rendition of directing conventions is proposed Fuzzy Enhanced Load Aware Routing in Ad hoc (FE-LARA). Here, WNs climate is recreated in MATLAB for different situations to figure LARA and FE-LARA. Outcomes got from this extensive investigation discover that FE-LARA offers a strong improvement in opposition to winning methodology with LARA and it largely concentrates for corresponding flow of load of data amidst various multi-paths which are exposed, lower queue length for various nodes. A network would consequently be resilient to node catastrophes and activate through diminutive or no mainstay substructure
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CNN-based Security Authentication for Wireless Multimedia Devices
Статья научная
Security is a major concern for wireless multimedia networks because of their role in providing various services. Traditional security techniques have inadequacies in identifying emerging security threats and also lacks in computing efficiency. Furthermore, conventional upper-layer authentication doesn’t provide any protection for physical layer, thus leading to leakage of privacy data. Keep these issues in mind, the paper has envisioned an artificial intelligence-based security authentication system that is lightweight, adaptive and doesn’t require any explicit programming. The neural network is built on convolutional filters which explore the data and learns the features or characteristic of the data. With this learned feature, the model will be able to recognize whether a wireless multimedia device present in a network is legitimate or not. Experimental analysis and validation have been performed on the trained model and ensure that the authentication of wireless multimedia devices can be achieved and also ensuring lightweight authentication system, which ensures less computation needs. The different neural model is also trained using gaussian noise of different standard deviation so that it can be used in a practical scenario like smart industry etc.
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CPW-fed Compact antenna for WiMAX/WLAN applications
Статья научная
A compact antenna with Coplanar waveguide (CPW) feed for WiMAX/WLAN applications is presented in this paper. Antenna is fabricated on FR4 substrate having size of (35mm×25mm).The rectangular antenna is etched with slit and stub which obtains triple band. The measured results shows that S11< ̶ 10dB impedance bandwidths are at 100MHz(2.39-2.49 GHz), 800MHz(3.4-4.2 GHz) and 1680 MHz(5.4-7.08 GHz).These frequency ranges meet the bandwidth requirement for Wireless local area network (WLAN) 2.4/5.8 GHz bands and Worldwide interoperability for microwave access (WiMAX) 3.5 GHz band. Bandwidth, S11, VSWR, radiation and gain characteristics of the antenna are investigated. Antenna exhibits good resemblance between measured and simulation results
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CPW-fed Wideband Antenna with U-shaped Ground Plane
Статья научная
This paper proposes the design of CPW-fed wideband antenna with U-shaped ground plane. The proposed antenna is a simple printed antenna, which is fed by a 50Ω CPW line. The Antenna has a compact size of 13mm×25mm. To obtain wide bandwidth, a slot is cut in ground plane and radiating patch is modified. The proposed antenna yields the operating frequency range from 7.3GHz to 15.1GHz, which offers the bandwidth of 7.79GHz. Simulation has been performed by using CST Microwave Studio Software. This frequency range satisfies the system requirements for Narrowband PCS Services, Satellite, Cellular Phone, Domestic Public Land Mobile Communication and International Public Broadcasting applications.
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Статья научная
Multiple input multiple output (MIMO) is one of the key technology to accomplish the goal of the future wireless broadband communication.This paper deals with the bit error rate (BER) and capacity performance of the Vertical Bell laboratories layered space-time (VBALST) MIMO systems with a linear receiver such as minimum mean-square error (MMSE) and zero forcing (ZF) over Nakagami-m channel. Both the BER and the capacity of MIMO systems have been analyzed for different modulation techniques and also with various configurations of MIMO systems. We have also analyzed the VBLAST MIMO system performance in a higher SNR region.
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