TY  - JOUR
AU  - Popkonstantinović, Branislav
AU  - Obradović, Ratko
AU  - Stojićević, Miša
AU  - Jeli, Zorana
AU  - Cvetković, Ivana
AU  - Vasiljević, Ivana
AU  - Milojević, Zoran
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3501
AB  - This paper describes and explains the synthesis of an astronomical clock mechanism which displays the mean position of the Sun, the Moon, the lunar node and zodiac circle as well as the Moon phases and their motion during the year as seen from the Earth. The clock face represents the stereographic projection of the celestial equator, celestial tropics, zodiac circle (ecliptic) and horizon for the latitude of Belgrade from the north celestial pole to the equator plane. The observed motions of celestial objects are realized by a set of clock gear trains with properly calculated gear ratios. The method of continued fraction is applied in the computation of proper and practically applicable gear ratios of the clock gear trains. The fully operational 3D model of the astronomical clock is created and the motion study of its operation is accomplished by using the SolidWorks 2016 application. The simulation results are compared with the ephemeris data and the detected differences are used to evaluate the long-term accuracy of the astronomical clock operation. The presented methods of the clock mechanism synthesis can be useful for the design, maintenance and conservation of large-scale city astronomical clocks since these clocks represent a precious historical and cultural heritage of European civilization.
PB  - MDPI, Basel
T2  - Applied Sciences-Basel
T1  - The Design and Simulation of an Astronomical Clock
IS  - 9
VL  - 11
DO  - 10.3390/app11093989
ER  - 

@article{
author = "Popkonstantinović, Branislav and Obradović, Ratko and Stojićević, Miša and Jeli, Zorana and Cvetković, Ivana and Vasiljević, Ivana and Milojević, Zoran",
year = "2021",
abstract = "This paper describes and explains the synthesis of an astronomical clock mechanism which displays the mean position of the Sun, the Moon, the lunar node and zodiac circle as well as the Moon phases and their motion during the year as seen from the Earth. The clock face represents the stereographic projection of the celestial equator, celestial tropics, zodiac circle (ecliptic) and horizon for the latitude of Belgrade from the north celestial pole to the equator plane. The observed motions of celestial objects are realized by a set of clock gear trains with properly calculated gear ratios. The method of continued fraction is applied in the computation of proper and practically applicable gear ratios of the clock gear trains. The fully operational 3D model of the astronomical clock is created and the motion study of its operation is accomplished by using the SolidWorks 2016 application. The simulation results are compared with the ephemeris data and the detected differences are used to evaluate the long-term accuracy of the astronomical clock operation. The presented methods of the clock mechanism synthesis can be useful for the design, maintenance and conservation of large-scale city astronomical clocks since these clocks represent a precious historical and cultural heritage of European civilization.",
publisher = "MDPI, Basel",
journal = "Applied Sciences-Basel",
title = "The Design and Simulation of an Astronomical Clock",
number = "9",
volume = "11",
doi = "10.3390/app11093989"
}

Popkonstantinović, B., Obradović, R., Stojićević, M., Jeli, Z., Cvetković, I., Vasiljević, I.,& Milojević, Z.. (2021). The Design and Simulation of an Astronomical Clock. in Applied Sciences-Basel
MDPI, Basel., 11(9).
https://doi.org/10.3390/app11093989

Popkonstantinović B, Obradović R, Stojićević M, Jeli Z, Cvetković I, Vasiljević I, Milojević Z. The Design and Simulation of an Astronomical Clock. in Applied Sciences-Basel. 2021;11(9).
doi:10.3390/app11093989 .

Popkonstantinović, Branislav, Obradović, Ratko, Stojićević, Miša, Jeli, Zorana, Cvetković, Ivana, Vasiljević, Ivana, Milojević, Zoran, "The Design and Simulation of an Astronomical Clock" in Applied Sciences-Basel, 11, no. 9 (2021),
https://doi.org/10.3390/app11093989 . .

TY  - JOUR
AU  - Vasiljević, Ivana
AU  - Obradović, Ratko
AU  - Durić, Isidora
AU  - Popkonstantinović, Branislav
AU  - Budak, Igor
AU  - Kulić, Luka
AU  - Milojević, Zoran
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3518
AB  - In recent years, digitization of cultural heritage objects, for the purpose of creating virtual museums, is becoming increasingly popular. Moreover, cultural institutions use modern digitization methods to create three-dimensional (3D) models of objects of historical significance to form digital libraries and archives. This research aims to suggest a method for protecting these 3D models from abuse while making them available on the Internet. The proposed method was applied to a sculpture, an object of cultural heritage. It is based on the digitization of the sculpture altered by adding local clay details proposed by the sculptor and on sharing on the Internet a 3D model obtained by digitizing the sculpture with a built-in error. The clay details embedded in the sculpture are asymmetrical and discreet to be unnoticeable to an average observer. The original sculpture was also digitized and its 3D model created. The obtained 3D models were compared and the geometry deviation was measured to determine that the embedded error was invisible to an average observer and that the watermark can be extracted. The proposed method simultaneously protects the digitized image of the artwork while preserving its visual experience. Other methods cannot guarantee this.
PB  - MDPI, Basel
T2  - Applied Sciences-Basel
T1  - Copyright Protection of 3D Digitized Artistic Sculptures by Adding Unique Local Inconspicuous Errors by Sculptors
IS  - 16
VL  - 11
DO  - 10.3390/app11167481
ER  - 

@article{
author = "Vasiljević, Ivana and Obradović, Ratko and Durić, Isidora and Popkonstantinović, Branislav and Budak, Igor and Kulić, Luka and Milojević, Zoran",
year = "2021",
abstract = "In recent years, digitization of cultural heritage objects, for the purpose of creating virtual museums, is becoming increasingly popular. Moreover, cultural institutions use modern digitization methods to create three-dimensional (3D) models of objects of historical significance to form digital libraries and archives. This research aims to suggest a method for protecting these 3D models from abuse while making them available on the Internet. The proposed method was applied to a sculpture, an object of cultural heritage. It is based on the digitization of the sculpture altered by adding local clay details proposed by the sculptor and on sharing on the Internet a 3D model obtained by digitizing the sculpture with a built-in error. The clay details embedded in the sculpture are asymmetrical and discreet to be unnoticeable to an average observer. The original sculpture was also digitized and its 3D model created. The obtained 3D models were compared and the geometry deviation was measured to determine that the embedded error was invisible to an average observer and that the watermark can be extracted. The proposed method simultaneously protects the digitized image of the artwork while preserving its visual experience. Other methods cannot guarantee this.",
publisher = "MDPI, Basel",
journal = "Applied Sciences-Basel",
title = "Copyright Protection of 3D Digitized Artistic Sculptures by Adding Unique Local Inconspicuous Errors by Sculptors",
number = "16",
volume = "11",
doi = "10.3390/app11167481"
}

Vasiljević, I., Obradović, R., Durić, I., Popkonstantinović, B., Budak, I., Kulić, L.,& Milojević, Z.. (2021). Copyright Protection of 3D Digitized Artistic Sculptures by Adding Unique Local Inconspicuous Errors by Sculptors. in Applied Sciences-Basel
MDPI, Basel., 11(16).
https://doi.org/10.3390/app11167481

Vasiljević I, Obradović R, Durić I, Popkonstantinović B, Budak I, Kulić L, Milojević Z. Copyright Protection of 3D Digitized Artistic Sculptures by Adding Unique Local Inconspicuous Errors by Sculptors. in Applied Sciences-Basel. 2021;11(16).
doi:10.3390/app11167481 .

Vasiljević, Ivana, Obradović, Ratko, Durić, Isidora, Popkonstantinović, Branislav, Budak, Igor, Kulić, Luka, Milojević, Zoran, "Copyright Protection of 3D Digitized Artistic Sculptures by Adding Unique Local Inconspicuous Errors by Sculptors" in Applied Sciences-Basel, 11, no. 16 (2021),
https://doi.org/10.3390/app11167481 . .