Tài liệu miễn phí Kĩ thuật Viễn thông

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Classes of functions for propagation of topic trust in social network

The purpose of this paper is to study functions for computing topic trust in social networks. The focus is to describe classes of functions for propagation of trust among connected peers. Some of them represent properties of relationships between user’s interests on topic and trust trustworthiness. Some other functions describe computational methods of topic trust values along a path and from various paths. Based on these classes of functions, we construct an algorithm for computing topic trust via propagation of topic trust among nodes.

12/29/2020 2:03:08 PM +00:00

Computational topic trust with user’s interests based on propagation and similarity measure in social networks

The purpose of this work is to present a model of trust computation being defined by means of the context of user’s interests and degrees of direct interaction among peers. A dynamic structure of social network based on a hierarchy of peers into k-layer neighbors w.r.t. a given source peer is investigated. We introduce a similarity measure being constructed from the space of vectors of users’ interests. Up on the location of a target peer w.r.t. the hierarchy, we propose methods of estimating trust values via propagation as well as the similarity. Some classes of functions for supporting the computation of trust values in these cases are also considered.

12/29/2020 2:01:59 PM +00:00

Integrating interaction and similarity threshold of user’s interests for topic trust computation

This paper proposes a computational model of topic trust being constructed from users similarity and levels of their interaction. It is defined as function of similarity degrees in interests and levels of interaction in topics among users. Based on this model, we may estimate trustworthy values among peers in all cases with some direct and indirect interaction or without any interaction. The proposed approach may overcome limitation in the high computational cost of propagation methods based on graph models.

12/29/2020 2:01:53 PM +00:00

Improving TDWZ correlation noise estimation: A deep learning based approach

Transform domain Wyner-Ziv video coding (TDWZ) has shown its benefits in compressing video applications with limited resources such as visual surveillance systems, remote sensing and wireless sensor networks. In TDWZ, the correlation noise model (CNM) plays a vital role since it directly affects to the number of bits needed to send from the encoder and thus the overall TDWZ compression performance. To achieve CNM with high accurate for TDWZ, we propose in this paper a novel CNM estimation approach in which the CNM with Laplacian distribution is adaptively estimated based on a deep learning (DL) mechanism

12/29/2020 1:56:56 PM +00:00

Modified dijkstra’s routing algorithm for security with different trust degrees

A great number of efficient methods to improve the performance of the networks have been proposed in physicallayer security for wireless communications. So far, the security and privacy in wireless communications is optimized based on a fixed assumption about the trustworthiness or trust degrees (TD) of certain wireless nodes. The nodes are often classified into different types such as eavesdroppers, untrusted relays, and trusted cooperative nodes. Wireless nodes in different networks do not completely trust each other when cooperating or relaying information for each other. Optimizing the network based on trust degrees plays an important role in improving the security and privacy for the modern wireless network.

12/29/2020 1:56:48 PM +00:00

Mutual coupling reduction in microstrip antennas using defected ground structure

A Multiple Input Multiple Output (MIMO) antenna with high isolation is proposed in this paper. The proposed antenna includes two sets of four elements (2 × 2) and it is yielded at the central frequency of 5.5 GHz for Wireless Local Area Network (WLAN) applications. Based on RT5880 with height of 1.575 mm, the overall size of MIMO antenna is 140 × 76 × 1.575 mm3 . To get high isolation between antenna elements, a Defected Ground Structure (DGS) is integrated on ground plane. Besides, the MIMO antenna witnesses a large bandwidth of 9.1% and an efficiency of 90% while the pick gain is 8.5 dBi. The measurement results are compared to simulation ones to verify the performance of the proposed antenna.

12/29/2020 1:56:40 PM +00:00

A new linear printed vivaldi antenna array with low sidelobe level and high gain for the band 3.5 GHz

This paper proposes a new design of a low sidelobe level (SLL) and high gain linear printed Vivaldi antenna array. The array composes of two parts, which are a linear Vivaldi antenna array and a back reflector. The array consists of 10 single Vivaldi antennas and a new series-fed network, those are based on Rogers RO4003C substrate (ε = 3.55) with the dimension of 450 × 140 × 1.524 mm3 .

12/29/2020 1:56:34 PM +00:00

2D parity product code for TVS online fault correction and detection

This paper presents a 2D Parity Product Code (2D-PPC) for TSV fault-tolerance with the ability to correct one fault and detect, at least, two faults. In an implementation of 64-bit data and 81-bit code-word, 2D-PPC can detect over 71 faults, on average. Its encoder and decoder decrease the overall latency by 38.33% when compared to the Single Error Correction Double Error Detection code. In addition to the high detection rates, the encoder can detect 100% of its gate failures, and the decoder can detect and correct around 40% of its individual gate failures. The squared 2D-PPC could be extended using orthogonal Latin square to support extra bit correction.

12/29/2020 1:56:27 PM +00:00

Evaluating the effect of self-interference on the performance of full-duplex two-way relaying communication with energy harvesting

– In this paper, we study the throughput and outage probability (OP) of two-way relaying (TWR) communication system with energy harvesting (EH). The system model consists two source nodes and a relay node which operates in full-duplex (FD) mode. The effect of self-interference (SI) due to the FD operation on the system performance is evaluated for both one-way full duplex (OWFD) and two-way full duplex (TWFD) diagrams where the amplify-and-forward (AF) relay node collects energy harvesting with the time switching (TS) scheme. We first propose an individual OP expression for each specific source. Then, we derive the exact closed-form overall OP expression for the OWFD diagram...

12/29/2020 1:56:13 PM +00:00

Low-dose ct image denoising using image decomposition and sparse representation

This paper contributes an efficient denoising method for low-dose CT images. A noisy image is decomposed into three component images of low, medium and high frequency bands; noise is mainly presented in the medium and high component images. Then, by exploiting the fact that a small image patch of the noisy image can be approximated by a linear combination of several elements in a given dictionary of noise-free image patches generated from noise-free images taken at nearly the same position with the noisy image, noise in these medium and high component images are effectively eliminated. Specifically, we give new solutions for image decomposition to easily control the filter parameters, for dictionary construction to improve the effectiveness and reduce the running-time. Instead of using a large dataset of patches, only a structured small part of patches extracted from the raw data is used to form a dictionary, to be used in sparse coding. In addition, we illustrate the effectiveness of the proposed method in preserving image details which are subtle but clinically important. Experimental results conducted on both synthetic and real noise data demonstrate that the proposed method is competitive with the state-of-the-art methods.

12/29/2020 1:55:58 PM +00:00

Impact of frequency shift on nonlinear compensation using optical phase conjugation for M-QAM signals

In this paper, we investigate the impact of frequency shift on the nonlinear compensation using OPC for high symbol rate, high level modulation format signals. This will be important to understand the tolerance of the OPC techniques against such a practical condition for actual system implementations.

12/29/2020 1:55:49 PM +00:00

A rank-deficient and sparse penalized optimization model for compressive indoor radar target localization

This paper aims to tackle these difficulties by formulating the task of wall clutter suppression and target image formation as a penalized minimization problem with low-rank and sparse regularizers. The former penalty is used to model the low-dimensional attribute of the wall reflections and the later regularizer is used to represent the image of the behind-the-wall targets. We develop an iterative algorithm based on the forward-backward proximal gradient technique to solve the regularized minimization problem, which removes wall interferences and forms an indoor target image simultaneously. The effectiveness of the proposed approach is validated using extensive experiments on both simulated and real radar data.

12/29/2020 1:55:41 PM +00:00

Hardware architectures of visible light communication transmitter and receiver for beacon-based indoor positioning systems

In this paper, we introduce a compact Polar-code-based VLC receivers. in which flicker mitigation of the system can be guaranteed even without RLL codes. In particular, we utilized the centralized bit-probability distribution of a pre-scrambler and a Polar encoder to create a non-RLL flicker mitigation solution. At the receiver, a 3-bit soft-decision filter was implemented to analyze signals received from the VLC channel to extract log-likelihood ratio (LLR) values and feed them to the Polar decoder. Therefore, the proposed receiver could exploit the soft-decoding of the Polar decoder to improve the error-correction performance of the system. Due to the non-RLL characteristic, the receiver has a preeminent code-rate and a reduced complexity compared with RLL-based receivers. We present the proposed VLC receiver along with a novel very-large-scale integration (VLSI) architecture, and a synthesis of our design using FPGA/ASIC synthesis tools.

12/29/2020 1:55:33 PM +00:00

Secure information flow for IoT applications

This paper discusses how to ensure security, i.e., confidentiality and integrity properties, for data in IoT applications. While confidentiality could be assessed via information flow analysis, integrity is ensured by error-correcting codes. In addition to errors, many communication channels also cause erasures, i.e., the demodulator cannot decide which symbol the received waveform represents. The paper proposes a method that might correct both errors and erasures together. Our method is efficient in reducing memory storage as well as decoding complexity.

12/29/2020 1:55:27 PM +00:00

Xây dựng ứng dụng Sổ liên lạc điện tử trong trường đại học

Bài viết giới thiệu về công nghệ điện toán đám mây và khả năng ứng dụng của nó trong việc xây dựng các ứng dụng di động, cụ thể là ứng dụng Sổ liên lạc điện tử, là một dịch vụ cung cấp thông tin từ nhà trường tới sinh viên/phụ huynh thông qua ứng dụng chạy trên các thiết bị di động.

12/29/2020 1:29:29 PM +00:00

Điều khiển và giám sát hệ thống tưới nước tự động sử dụng mạng không dây trong thời đại công nghệ IoT

Cung cấp đủ nước theo nhu cầu sinh trưởng của cây trồng là yếu tố quyết định đến năng suất. Do đó, bài viết đề xuất cấu trúc điều khiển hệ thống tưới nước tự động theo kiểu IoT đáp ứng được yêu cầu về độ ẩm theo đặc tính sinh trưởng của cây trồng.

12/29/2020 1:27:01 PM +00:00

Security capability analysis of cognitive radio network with secondary user capable of jamming and self-powering

This paper investigates a cognitive radio network where a secondary sender assists a primary transmitter in relaying primary information to a primary receiver and also transmits its own information to a secondary recipient. This sender is capable of jamming to protect secondary and/or primary information against an eavesdropper and self-powering by harvesting radio frequency energy of primary signals. Security capability of both secondary and primary networks are analyzed in terms of secrecy outage probability.

12/29/2020 1:04:24 PM +00:00

QoT aware load balancing routing in manet using relay type of amplify and forward based cooperative communications

In research topics to improve the performance of the mobile ad hoc networks (MANET), the load balancing routing has attracted many research groups because it is an effective solution to reduce traffic congestion. However, to balance the traffic load, the routing algorithm often has to choose some long routes. These routes pass through many hops and intermediate nodes, so the accumulated noise along with the route increases.

12/29/2020 1:04:12 PM +00:00

Generic framework for industrial 4.0 applications based on internet of things

In this framework, low-powered sensor nodes are based on the micro:bit platform, providing a multiple footprints for different sensor connections. The wireless capability on micro:bit provides a complete solution to deploy the system in such places that wire is impractical to draw. The data is wirelessly gathered by a basestation node that is powered by Android Things operating system provided by Google. This operating system is based on the Android platform for smart devices and Internet of Things products. The approach to this framework indicates a low cost and minimum setup and especially amenable for applications control. To support many applications with minimum modifications, the framework is designed for easy expansion by supporting popular serial connection ports, including the Universal Asynchronous Receiver/Transmitter and Serial Peripheral Interface.

12/29/2020 11:55:52 AM +00:00

Energy-efficiency approach for long range wireless communication

This research not only introduced the reference hardware of a sensor node in wireless sensor networks but also conducted experiments on typical LoRaTM network infrastructure. We conduct three different experiments to validate our proposed algorithm with real systems which use air quality sensors and an ultra-low-power micro-controller unit board from Texas instruments.

12/29/2020 11:55:19 AM +00:00

Applying attribute-based encryption on mobile devices

The paper also describes a few implementations of ABE applied in the cryptography community and the challenges of integrating ABE into real-world applications. Finally, the paper proposes an implementation of ABE for Android mobile devices. This implementation associated with the Kerberos protocol can be applied to secured data sharing applications. The Kerberos protocol aims at providing mutual authentication for the client server model. Experiments have evaluated the proposed ABE implementation on Android mobile devices along with the Kerberos system. The evaluation also includes ABE performance with discussions and lessons learned.

12/29/2020 11:52:36 AM +00:00

Đánh giá hiệu năng cơ chế đa truy cập phi trực giao NOMA cho đường lên của mạng 5G

Trong bài viết này nghiên cứu đánh giá hiệu năng của cơ chế phi trực giao (NOMA) trong đường lên của mạng 5G. Mô hình được khảo sát trong bài báo này gồm 1 trạm cơ sở và 2 người dùng với hệ số kênh truyền, khoảng cách… khác nhau.

12/29/2020 8:38:41 AM +00:00

Kỹ thuật phân đoạn chùm trong mạng chuyển mạch chùm quang

Bài viết này nhằm phân tích một số kỹ thuật phân đoạn chùm kết hợp với lập lịch và đường trễ quang FDL; đánh giá thông qua gói mô phỏng OBS0.9a trên phần mềm mô phỏng NS2-OBS.

12/29/2020 4:02:12 AM +00:00

Kỹ thuật kiểm thử hồi qui hiệu quả cho phát triển ứng dụng di động

Bài viết đề xuất một kỹ thuật kết hợp lựa chọn ca kiểm thử, xác định mức độ ưu tiên và tối thiểu hóa số lượng ca kiểm thử bao phủ được mã nguồn sửa đổi của chương trình. Kỹ thuật xác lập ưu tiên và giảm thiểu ca kiểm thử được đề xuất trong nghiên cứu này cùng với qui trình thực hiện kiểm thử hồi qui cho ứng dụng di động trong môi trường phát triển linh hoạt mang lại hiệu quả cao cho hoạt động kiểm thử hồi qui về mặt chi phí và thời gian.

12/29/2020 4:02:05 AM +00:00

Một phương pháp cải thiện chất lượng trải nghiệm trong truyền video trên mạng IP

Bài viết đề xuất một phương pháp cải tiến quản lý hàng đợi tích cực Blue để cải thiện chất lượng truyền video trên môi trường mạng IP. Thông qua sử dụng phương pháp điều chỉnh xác xuất đánh dấu (loại bỏ) gói tin trong giải thuật quản lý hàng đợi tích cực Blue để làm giảm xác suất mất gói tin đang video trong các ứng dụng truyền video trên mạng. Sử dụng công cụ mô phỏng NS-2 để kiểm nghiệm trên các mẫu video chuẩn mpeg cho thấy chất lượng truyền video đã được cải thiện đáng kể.

12/29/2020 4:00:51 AM +00:00

Một thuật toán định tuyến xuyên lớp đảm bảo QOT trong mạng manet

Bài báo tập trung nghiên cứu các thuật toán định tuyến dưới điều kiện ràng buộc ảnh hưởng của các hiệu ứng vật lý xảy ra trên đường truyền. Từ đó, chúng tôi cải tiến thuật toán DSR sử dụng kỹ thuật định tuyến xuyên lớp kết hợp với agent tĩnh nhằm giảm xác suất nghẽn mạng, giảm thiểu số gói tin điều khiển. Các hiệu ứng vật lý được xem xét bao gồm nhiễu tích lũy trên đường truyền, suy hao công suất tín hiệu qua môi trường truyền dẫn.

12/29/2020 3:59:36 AM +00:00

Thách thức đối với ứng dụng dùng mạng 5G trong bối cảnh công nghệ 4.0

Bài viết đề cập đến phạm vi truyền thông, dung lượng băng thông, độ trễ, độ tin cậy, năng lượng, bảo mật và quyền riêng tư và xác định các thách thức của các ứng dụng dùng mạng thông tin 5G trong bối cảnh hiện nay.

12/29/2020 1:22:32 AM +00:00

Lesson Regulatory and spectrum aspects of 5G and IoT/M2M

Lesson Regulatory and spectrum aspects of 5G and IoT/M2M Unique characteristics of Indian telecom industry; machine to machine (M2M) communications-trends; IoT/M2M applications; IoT in healthcare; IoT in financial services...

12/28/2020 6:20:34 PM +00:00

Lesson Regulatory and spectrum aspects of 5G technology

Lesson Regulatory and spectrum aspects of 5G technology present 5G technology; mobile wireless generati; spectrum bands used for 4G in India; overview of timeline for imt development and deployment....

12/28/2020 6:20:27 PM +00:00

Đề thi cuối học kỳ I năm học 2017-2018 môn Xử lý số hình ảnh và âm thanh - ĐH Bách khoa TP.HCM

Đề thi cuối học kỳ I năm học 2017-2018 môn Xử lý số hình ảnh và âm thanh giúp các bạn học sinh có thêm tài liệu ôn tập, luyện tập nhằm nắm vững được những kiến thức, kĩ năng cơ bản, đồng thời vận dụng kiến thức để giải các bài tập một cách thuận lợi.

12/28/2020 5:38:36 PM +00:00