A Lossless Watermarking for 3D STL Model Based on Entity Rearrangement and Bit Mapping

2017 ◽  
Vol 9 (2) ◽  
pp. 25-37 ◽  
Author(s):  
Juan Chen ◽  
Fei Peng ◽  
Jie Li ◽  
Min Long

With the wide application of 3D STL model in 3D printing, much attention has been paid to its content security and copyright protection. Based on entity rearrangement and bit mapping, a lossless and high capacity watermarking scheme is proposed for 3D STL model. Experimental results and analysis show that the average capacity is improved 0.71bits/facet compared with the original entity rearrangement method, and the capacity is 0.247 bits/entity larger than that of the optimal capacity of the standard entity rearrangement method. It can achieve good efficiency and it is robust against translation, rotation and even scaling. It has potential application in secret communication and copyright protection of 3D STL model.

2021 ◽  
Vol 1131 (1) ◽  
pp. 012020
Author(s):  
Neha Janu ◽  
Ankit Kumar ◽  
Pankaj Dadheech ◽  
Gajanand Sharma ◽  
Ashutosh Kumar ◽  
...  

2021 ◽  
Vol 19 (1) ◽  
pp. 432-441
Author(s):  
Pawel Jeżowski ◽  
Olivier Crosnier ◽  
Thierry Brousse

Abstract Energy storage is an integral part of the modern world. One of the newest and most interesting concepts is the internal hybridization achieved in metal-ion capacitors. In this study, for the first time we used sodium borohydride (NaBH4) as a sacrificial material for the preparation of next-generation sodium-ion capacitors (NICs). NaBH4 is a material with large irreversible capacity of ca. 700 mA h g−1 at very low extraction potential close to 2.4 vs Na+/Na0. An assembled NIC cell with the composite-positive electrode (activated carbon/NaBH4) and hard carbon as the negative one operates in the voltage range from 2.2 to 3.8 V for 5,000 cycles and retains 92% of its initial capacitance. The presented NIC has good efficiency >98% and energy density of ca. 18 W h kg−1 at power 2 kW kg−1 which is more than the energy (7 W h kg−1 at 2 kW kg−1) of an electrical double-layer capacitor (EDLC) operating at voltage 2.7 V with the equivalent components as in NIC. Tin phosphide (Sn4P3) as a negative electrode allowed the reaching of higher values of the specific energy density 33 W h kg−1 (ca. four times higher than EDLC) at the power density of 2 kW kg−1, with only 1% of capacity loss upon 5,000 cycles and efficiency >99%.


2007 ◽  
Vol 26 (4) ◽  
pp. 319-330 ◽  
Author(s):  
Ming-Chiang Hu ◽  
Der-Chyuan Lou ◽  
Ming-Chang Chang

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