scholarly journals Investigation of the computational complexity of methods for hiding information in cluster steganosystems

Radiotekhnika ◽  
2021 ◽  
pp. 77-87
Author(s):  
K.Yu. Shekhanin ◽  
S.V. Pshenichnaya ◽  
A.A. Kuznetsov

Several methods of technical steganography are currently known. Hiding information in a model in 3D printing, this industry of hiding information has certain advantages and disadvantages, namely: the relatively high cost of creating a hidden message and the difficulty in reading the information. The second area of technical steganography is related to network traffic. In this method, information can be hidden, for example, in the header fields of protocols, or, for example, the transmission of a hidden message by sending packets in a certain sequence. There are also methods of hiding information in the structure of the file system, but the known methods are either capable of hiding a small amount of information, or have an insufficient level of resistance to detection. Thus, an urgent task is to develop a method for hiding information, which is able to hide more information and has a higher level of resistance to detection, with a satisfactory level of computational complexity. This paper presents methods of technical steganography based on the structural features of file systems in storage media, in particular, hiding information in the FAT file system by mixing clusters of certain key files (cover files). Methods of hiding information in the structure of a clustered file system by mixing clusters of cover files require significant computational resources. In this paper, research has been carried out on methods to increase computational efficiency in terms of the amount of required RAM, and the number of the required number of basic operations to hide a message.

2016 ◽  
Vol 5 (01) ◽  
pp. 4723 ◽  
Author(s):  
Bhusnure O. G.* ◽  
Gholve V. S. ◽  
Sugave B. K. ◽  
Dongre R. C. ◽  
Gore S. A. ◽  
...  

Many researchers have attempted to use computer-aided design (C.A.D) and computer-aided manufacturing (CAM) to realize a scaffold that provides a three-dimensional (3D) environment for regeneration of tissues and organs. As a result, several 3D printing technologies, including stereolithography, deposition modeling, inkjet-based printing and selective laser sintering have been developed. Because these 3D printing technologies use computers for design and fabrication, and they can fabricate 3D scaffolds as designed; as a consequence, they can be standardized. Growth of target tissues and organs requires the presence of appropriate growth factors, so fabrication of 3Dscaffold systems that release these biomolecules has been explored. A drug delivery system (D.D.S) that administrates a pharmaceutical compound to achieve a therapeutic effect in cells, animals and humans is a key technology that delivers biomolecules without side effects caused by excessive doses. 3D printing technologies and D. D. Ss have been assembled successfully, so new possibilities for improved tissue regeneration have been suggested. If the interaction between cells and scaffold system with biomolecules can be understood and controlled, and if an optimal 3D tissue regenerating environment is realized, 3D printing technologies will become an important aspect of tissue engineering research in the near future. 3D Printing promises to produce complex biomedical devices according to computer design using patient-specific anatomical data. Since its initial use as pre-surgical visualization models and tooling molds, 3D Printing has slowly evolved to create one-of-a-kind devices, implants, scaffolds for tissue engineering, diagnostic platforms, and drug delivery systems. Fuelled by the recent explosion in public interest and access to affordable printers, there is renewed interest to combine stem cells with custom 3D scaffolds for personalized regenerative medicine. Before 3D Printing can be used routinely for the regeneration of complex tissues (e.g. bone, cartilage, muscles, vessels, nerves in the craniomaxillofacial complex), and complex organs with intricate 3D microarchitecture (e.g. liver, lymphoid organs), several technological limitations must be addressed. Until recently, tablet designs had been restricted to the relatively small number of shapes that are easily achievable using traditional manufacturing methods. As 3D printing capabilities develop further, safety and regulatory concerns are addressed and the cost of the technology falls, contract manufacturers and pharmaceutical companies that experiment with these 3D printing innovations are likely to gain a competitive edge. This review compose the basics, types & techniques used, advantages and disadvantages of 3D printing


2012 ◽  
Vol 263-266 ◽  
pp. 1979-1986
Author(s):  
Qiang Li ◽  
Li Gu Zhu ◽  
Sai Feng Zeng

Updates discovery is the key problem of data synchronization; it has been used to generate updates operations. The traditional algorithms ignore the modify semanteme, cause the updates operations increased. A new file updating discovery algorithm that supports semantic synchronization is proposed in this paper. The algorithm takes advantage of semantic info, which preserved in file system journal, to accurately recognize users originally modify intents. We take the NTFS file system as an example to realize and test the new algorithm. By comparison, the algorithm effectively reduces synchronization requests. Experiments show that, the algorithm cans timely respond to users’ modification and support massive file changes that occurred in short time. The algorithm is designed based on the basic features of file system journal, and can be applied to other file systems.


2021 ◽  
Vol 17 (3) ◽  
pp. 1-25
Author(s):  
Bohong Zhu ◽  
Youmin Chen ◽  
Qing Wang ◽  
Youyou Lu ◽  
Jiwu Shu

Non-volatile memory and remote direct memory access (RDMA) provide extremely high performance in storage and network hardware. However, existing distributed file systems strictly isolate file system and network layers, and the heavy layered software designs leave high-speed hardware under-exploited. In this article, we propose an RDMA-enabled distributed persistent memory file system, Octopus + , to redesign file system internal mechanisms by closely coupling non-volatile memory and RDMA features. For data operations, Octopus + directly accesses a shared persistent memory pool to reduce memory copying overhead, and actively fetches and pushes data all in clients to rebalance the load between the server and network. For metadata operations, Octopus + introduces self-identified remote procedure calls for immediate notification between file systems and networking, and an efficient distributed transaction mechanism for consistency. Octopus + is enabled with replication feature to provide better availability. Evaluations on Intel Optane DC Persistent Memory Modules show that Octopus + achieves nearly the raw bandwidth for large I/Os and orders of magnitude better performance than existing distributed file systems.


Author(s):  
E. V. Kudryavtseva ◽  
V. V. Kovalev ◽  
E. S. Zakurinova ◽  
G. Muller-Kamskii ◽  
V. V. Popov

Introduction. Despite the notable and rapid progress in the development of medical 3D printing in recent years, not much is known about the use of this technology in obstetrics and gynecology.The purpose of our review of scientific literature was to determine the current level of 3D printing development, discuss the closest and long term prospects for using this technology in obstetrics and gynecology, and analyze its potential advantages and disadvantages.Materials and methods. We searched for scientific literature. 378 papers passed a three-step screening, as a result of which 42 sources were selected for the final scientific review.Results and discussion. The main areas in which dimensional printing can be used in this area of medicine is the creation of simulation models and training for students, the creation of anatomical models for preoperative preparation, the surgical instruments, the creation of new dosage drug forms (including transvaginal ones), and bioprinting of organs and tissues.Conclusion. The presented literary review allows us to conclude that 3D printing the obstetrics and gynecology is a current rapidly developing direction. The organization of 3D modeling and printing laboratories can significantly increase the efficiency of teaching students and residents. In addition, obstetricians-gynecologists and surgeons should be informed about the possibility of 3D printing surgical instruments according to an individual design. It can inspire them to implement their own ideas and develop domestic innovative developments. Three-dimensional printing of dosage forms and bioprostheses requires more complex technological solutions, and is not yet used in clinical practice. However, given the enormous prospects for these areas, various grants should be envisaged for their development in Russia


2019 ◽  
Vol 34 (09) ◽  
pp. 1658-1661
Author(s):  
Stojan Mitrić

Main contribution of this paper is comparison of 3D printing technologies with detailed description of their work processes, usage of technologies in different applications and their advantages and disadvantages. This paper also describes software that are most commonly used in 3D printing world, and example of usage of 3D printing in Apiculture for creating system of rollers for making beeswax foundations.


2019 ◽  
Vol 3 (9) ◽  
pp. 283-289
Author(s):  
Shuchi Sukul ◽  
Goldy Rathee ◽  
Parimal Anand ◽  
Sakshi Kataria ◽  
Pratibha Taneja

OBJECTIVES: The present research was conducted to assess incidences of root microcracks caused by hand and rotary file system at different lengths MATERIAL AND METHODS: This in-vitro study was undertaken to assess incidence of root microcracks caused by hand and rotary file system at different lengths In total, 100 the mandibular premolar with straight roots determined with intact, fully formed apices were taken. Samples were randomly distributed into 5 groups based on the file system used: a) Group A: Control, b) Group B: Reciproc, c) Group C: WaveOne, d) Group D: One Shape and e) Group E: ProTaper. Pearson Chi-square test was used to determine the differences between groups. The dentinal defects were expressed as percentage of samples with microcracks in each group. Level of statistical significance was set at p-value less than 0.05. RESULTS: The chi square test was used to compare the Distribution of the number of teeth in which cracks were observed on the horizontal sections. It was found to be significant with group ProTaper showing maximum cracks at 3,6,9 mm level as compared to other file systemCONCLUSION: Nickel-titanium instruments causes cracks on the apical root surface or in the root canal wall. ProTaper causes maximum dentinal cracks as compared to other file systems


2021 ◽  
Vol 2103 (1) ◽  
pp. 012033
Author(s):  
M A Kotov ◽  
N A Monakhov ◽  
S A Poniaev ◽  
P A Popov ◽  
K V Tverdokhlebov

Abstract The features of 3D printing method for rapid prototyping and manufacturing of models for a pulsed high-speed gas-dynamic experiment are considered. Modern additive technologies allow the production of models. The basic properties of the materials and the advantages of 3D printing methods are described. The structure and properties of the obtained models can be unattainable using traditional manufacturing techniques. The design of the wind tunnel nozzle block is considered, which provides for the production of profiled contours using 3D printing. The advantages and disadvantages of use of such units on the shock tube are considered.


2015 ◽  
Vol 713-715 ◽  
pp. 2418-2422
Author(s):  
Lei Rao ◽  
Fan De Yang ◽  
Xin Ming Li ◽  
Dong Liu

Data management has experienced three stages: labor management, file systems, and database systems. In this paper, manage equipment data using a combination of HDFS file system and HBase database: the principles of HBase data management is studied; equipment data’s reading and writing processes is established; data model of equipment database is designed based on HBase.


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