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As a leading contemporary British scholar of critical communication, Christian Fuchs has long devoted himself to the study of human communication in the digital age from the perspective of academic tradition of Western Marxism, thus systematically proposing the critical theory of communication. Based on this, the paper aims to explore the basic clues of the formation of Fuchs' critical theory of communication, mainly by researching Fuchs' academic dialogues and debates with thinkers such as Marx and Engels, scholars of the Frankfurt School and Dallas W. Smythe through the method of intellectual history. In conclusion, it finds that from historical materialism and labor theory of value to critical theory and audience commodity, all of them have been critically interpreted and digitally combined by Fuchs, forming the historical foundation of his critical theory of communication. [ABSTRACT FROM AUTHOR]

Chinese tea culture has a long history and is an important carrier of Chinese excellent traditional culture. Chinese traditional tea making techniques and related customs have been included in the representative list of the intangible cultural heritage of humanity, highlighting the significant achievements of the development of Chinese tea culture and tea industry. According to investigation, there are still some problems in the development of tea culture, such as insufficient popularization, unbalanced regional development, inadequate influence as a whole. It suggests that we focus on the inheritance and protection of tea intangible cultural heritage, optimize the tea culture supervision and service system, deepen the connotation of tea culture research, and promote the integration of all elements of tea tourism. Besides, we need to strengthen the digital communication of tea culture, and promote the high-quality development of tea culture, thus enhancing the international influence of Chinese tea culture. [ABSTRACT FROM AUTHOR]

Digital information technology has made human beings move into a mixed space where virtuality and reality are integrated. Maps, that have always been used as the abstraction and interpretation of the real world and assist us to cognize the real world, are facing new challenges. Under the new digital and communication situations, maps need to incorporated digital virtual spaces and analyze the impacts brought by virtuality and reality, nihility and existence and the interpromotion of void and solid. Game maps are suitable carrier in this paper to analyze and discover the relations between the virtuality and the reality. Game map has seven elements including the time, the place, the personage, the object, the event, the phenomenon and the scenario to describe the world. This paper analyzes their virtual and real characteristics, explores the relationships and the interactions between virtual world construction and the reality, and discusses their feedback to the real world. This research can enrich the theoretical system of cartography and facilitate planning a smarter and more pleasant society for us. [ABSTRACT FROM AUTHOR]

BACKGROUND: To achieve a unified aesthetic restoration effect, digital smile design technologies have been introduced and gradually applied in clinical practice. However, due to the limitations and authenticity of the software’s own dental pictures, the promotion of the software encountered difficulties. Researchers found that using the digital smile design software to import previous similar cases may optimize this problem, making the design of the prosthesis authentic and personalized. OBJECTIVE: To verify the advantages and limitations of the case-based digital smile design method by comparing the effect of the case-based digital smile design method and the traditional aesthetic restoration method in the aesthetic restoration of anterior teeth. METHODS: From October 2018 to October 2020, 36 patients requiring aesthetic restoration of anterior teeth at the Department of Prosthodontics in Tianjin Stomatological Hospital were selected and randomly divided into experimental group and control group according to the sequence of treatment, with 18 patients in each group. In the experimental group, digital smile design technology was used to collect and import digital photos, and the diagnostic wax pattern and diagnostic decoration were made based on the pictures of the prostheses from the most similar cases in the past. Patients could obtain the digital smile design drawing and three-dimensional oral preview form for doctor-patient communication and design adjustment. The control group was treated with digital photography combined with colorimetric palettes. Immediately after aesthetic repair, patient satisfaction evaluation was performed. Aesthetic prostheses were clinically evaluated as per the modified United States Public Health Service (USPHS) criteria at 2 weeks, 6 months, and 12 months after aesthetic repair. RESULTS AND CONCLUSION: In terms of patient satisfaction, patients in the experimental group were more satisfied with the shape and color of the prosthetics than those in the control group (P < 0.05), and there was no significant difference in the comfort of the prosthetics and the time to seek medical treatment (P > 0.05). There was no significant difference between the two groups in postoperative prosthesis integrity, periodontal healthy, tooth sensitivity, edge fit, color matching, and occlusal relationship at 2 weeks after restoration (P > 0.05), while the experimental group was superior to the control group in color matching at 6 and 12 months after restoration (P < 0.05). To conclude, the case-based digital smile design technique is superior to the traditional method in doctor-patient communication, prosthesis color and shape; however, there are limitations such as the limited number of previous cases and the increased workload and cost of the digital smile design process. [ABSTRACT FROM AUTHOR]

Objects: Micro landform is an important basis for safe operation of transmission lines engineering, the risk division of lines icing and the calculation of energy consumption during the construction period of transmission lines. As the national grid extends and voltage levels increases, there are a lot of transmission lines passing through the micro landform area and damaged seriously. The traditional macro geomorphologic map can not show the micro landform characteristics accurately. It is subjective and costly for identifying micro landform by experts on the spot base on aerial photography and satellite images. Furthermore, it is difficult to meet actual engineering requirements. The automatic extraction micro landform of transmission lines is not only a requirement for digital transmission lines landform analysis precisely, but also a prerequisite and guarantee for the construction of power grid projects under complex landform conditions. Methods: According to the classification system of micro landform in the specifications, the micro landform types of transmission lines were investigated and five micro landform types including yakou, mountain, uplift, canyon and vapor were proposed. The micro landform type with yakou, mountain, uplift, canyon focuses on regional terrain complexity and relief, as while vapour landform focuses on the causes of the disaster. A decision-making scheme was proposed by terrain position index, slope, relative elevation and water distance, and a method of transmission line micro landform extraction based on grid digital elevation model(DEM) was constructed. About the vapor landform, the water distribution data were applied to the experimental area, the water area units were divided, and water body distance was calculated by grid statistics.Results: 9 transmission lines DEM data of a power grid company during 2012—2018 were used for extraction experiment. The micro landform type of yakou, mountain, uplift, canyon and vapor was extracted effectively, the position and tendency of the micro landform could be discriminated by the extraction results, and the statistical parameters of each transmission lines micro landform in the experimental area were obtained. A comparative analysis of disaster data form the influence of micro landform was added. It was found that the proportion of typical micro landform area where the disaster occurred was over 90%, much higher than the proportion of micro landform in the non-disaster area.Conclusions: The topographic position index, slope, relative elevation and water body distance were adopted to describe the five typical micro landform characteristics of the transmission line with digital terrain analysis technology and the existing transmission line micro landform classification system. Mined the micro landform information, a micro landform extraction method of grid DEM for transmission line was established. Compared with the traditional manual sketching method, it is simple and efficient, and the boundary contour of the extraction results was obvious, which could provide basic support for transmission line construction. [ABSTRACT FROM AUTHOR]

In order to solve the issue of malicious phonily occupying seats for some ticket agents or passengers in the process of air ticket sales, this paper proposed a blockchain system scheme based on the improved PoA consensus mechanism. The scheme used the alliance blockchain as a communication platform among airlines, adopted credit points and dynamic grading to build a new PoA consensus mechanism, protected passengers ' private information with hash algorithm, and achieved digital storage of ID information, registration of passengers, storage and sharing of passenger booking information for airline corporations relying on smart contracts. The prototype system trial operation shows that the system can timely detect and effectively stop the phonily occupying seats behavior. After analysis and evaluation, the program has the characteristics of privacy protection, decentralization and high security, and provides a new reference to solve the long-standing problem of phonily occupying seats in the civil aviation field. [ABSTRACT FROM AUTHOR]

The digital trunking system has the characteristics that the calling mode is mainly group calling and the communication mode is mostly half duplex. For the problem that the traditional user classification method couldn't meet the classification requirements of digital cluster users, this paper proposed a digital cluster user classification method based on improved RFM model. Firstly, it introduced the average speech duration attribute to establish the recency vitality speak (RVS) model. Then, it used the analytic hierarchy process to determine the weight of each parameter in the model. Finally, it used the K-means + + clustering algorithm to classify digital cluster users. The simulation result shows that, by using the user classification method proposed in this paper, the accuracy of digital cluster user classification can reach more than 87. 9% . [ABSTRACT FROM AUTHOR]

For the security problem of the spread of digital image and the digital image encryption from plaintext and too depend on the chaotic systems, this paper proposed a digital image encryption and monitoring algorithm combined with plaintext-related chaotic mapping and SHA-256. The algorithm used the SHA-256 algorithm to calculate the hash value as record to monitor the spread of digital image. Lorenz chaotic mapping generated the corresponding cryptogram by using forward diffusion, associated plaintext scrambling and backward diffusion to encrypt the digital image. The results show that the algorithm can resist many attacks and achieve the security and concealment of image propagation. [ABSTRACT FROM AUTHOR]

Aiming at the weak points in the experimental teaching both of Design of Machinery and Theory of Machines and Mechanisms, a comprehensive experimental system for gear transmission based on digital speckle correlation method is developed. The system consists of two parts; an experiment table of gear transmission and data processing. It can complete the measure experiments of gear structure parameters such as the principle of gear meshing, basic parameters, contact ratio, and the mechanics experiments of gear such as bending strength, contact strength, load distribution between teeth. Through non-contact real-time detection and image analysis, the principle of gear meshing and the theory of gear strength can be revealed and verified, the blank of gear strength experiment is filled, and the coverage of the experimental course to the knowledge points is increased. The practice of teaching shows that the application of advanced measurement technology in practical teaching can improve students' understanding of basic theoretical knowledge, and teachers' teaching level of design of machinery and theory of machines and mechanisms. [ABSTRACT FROM AUTHOR]

To deal with the problem that CIM should consume a lot of pseudo noise (PN) code resources when it increased the information transmission rate by increasing the number of mapping bits. This paper proposed a novel generalized code index modulation (GCIM). It divided the information bits of the transmitter into mapped bits and modulation bits and mapping modulation bits and mapped bits into modulation symbol and the indexes of the PN code groups respectively. The in-phase part and the orthogonal part of the modulation symbol spread spectrum by selecting activate PN code group respectively. What’s more, by increasing the number of the activate PN code of per transmission slot, which could increase the number of mapped bits and improved the spectral efficiency and energy efficiency of the system. The simulation results show that it is not better than CIM about 2 dB in the additive white Gaussian noise channel and about 1 dB in the Rayleigh fading channel at the same spectral efficiency. Nevertheless, compared with CIM, GCIM consumes significantly less PN code resources. [ABSTRACT FROM AUTHOR]

This paper proposed a twice channel estimation algorithm, in which used weighted coefficient to cancel ICI caused by Doppler frequency shift in high speed mobile environment. The algorithm achieved twice channel estimation. The first estimation provided channel state information to cancel the ICI under the premise of ensuring the symbol rate. In the case of ICI cancellation, the second estimation enhanced the channel estimation accuracy. Then the algorithm improved the simplified PIC algorithm, and introduced the weighting coefficient to make the residual error smallest after ICI cancellation based on the minimum mean square error criterion. The simulation results are in good agreement with the theoretical analysis. The proposed algorithm improves the estimation accuracy of rapidly time-varying channels. The maximum value of NMSE performance gain is0. 071 4, when the SNR is 0 dB. [ABSTRACT FROM AUTHOR]

The development of digital and online communication and information technologies that have led to the creation of personalized and proficient literary sites on the Internet and social networks are the beginning of a widespread dissemination of literary works in digital and cyberspace. "Virtual Literature" is used as a new literary theory that seeks to break down the format and content of traditional and written literature and create a new plan. After describing and understanding the realities of digital and cyberspace, this paper seeks to provide the necessary reasons for designing and expanding the definition of "virtual literary theory" based on scientific bases. The results of this study explain the Definition of virtual literature, origin and causes of the emergence of virtual literature, such as the increase of literary sites and channels, the examination of ordinary and non-professional individuals, and the multimedia content of virtual literature. [ABSTRACT FROM AUTHOR]

High-precision, high-speed clock synchronization is one of the key technologies for modern digital communication systems. Taking QPSK baseband communication system as an example, a clock synchronization method based on maximum likelihood synchronization error detection and polyphase filter is proposed. The operation principles and design procedures are analyzed in detail. Moreover, its performance is simulated by using Matlab. The results show that the requirement of Eb/N0 of the proposed method is less than 0.5dB higher compared with coherent demodulation with ideal timing at the BER close to 10-5. Its performance is satisfactory, with less computation, and easy to realize by modern DSP or FPGA technologies. [ABSTRACT FROM AUTHOR]

A novel dynamic bandwidth management mechanism based on the traffic prediction is presented to solve the problem of long delay caused by traditional demand assigned multiple access (DAMA). Firstly, the satellite terminals predict the queue length of the buffer, then send the reports to the network control center (NCC). Finally, the resources are allocated to the terminals by NCC. The algorithm performance is validated through the simulation for different types of traffic and different intervals between two consecutive prediction reports. The priority of real time traffic is considered. The delays of DAMA based on prediction and normal case are compared. The theoretical analysis and simulation results show that the new DAMA algorithm can efficiently tackle the problem of delay between bandwidth request and bandwidth assignment. [ABSTRACT FROM AUTHOR]

A design scheme for the body electrical system of a pan-electronic vehicle system is put forward with a two-level network (backbone network and local area network) as digital signal network, the vehicle power network as power source and the central coordination control unit for vehicle coordination control. The electrical equipment interconnection, the light and heavy current supply and the wire harness simplification are realized respectively by backbone network / local area network, distributed power network and standardized appliance interfaces. Thus an intelligent and standardized electrical system with high consistency, good expandability and high reliability is constructed. Finally a prototype vehicle is developed to verify the feasibility of the system. [ABSTRACT FROM AUTHOR]