• Journal of Korea Multimedia Society
• /
• v.22 no.12
• /
• pp.1368-1375
• /
• 2019

In this paper, an prediction method is proposed for coding of depth pictures using spherical modeling. An spherical surface which has the least error from original depth values is modeled in a block. Pixels in the block are predicted through the parameters of the modeled spherical surface. Simulation results show that average prediction errors and entropy powers are improved to 30% and 200% comparing to the intra prediction of H.264/AVC, selection ratios of the proposed spherical modeling mode is more than 25%.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.1028-1032
• /
• 1995

This paper describes the manufacture of spherical and aspherical surface on glass, superalloy and ceramic components. The rotationally symmetricallenses, and the ceramic or superalloy molds with spherical shapes are mainly generated by cutting processes on CNC lathe machine or 4,5 axis CNC machining centers. Recently, spherical shape parts require more precise and efficent machining technologies for wide material range such as optical lens of the lithography device in semiconductor manufacturing processes or the high precision mold machining of anti-chemical, anti-wear materials. In this paper, we introduce a newly developed infeed grinding machine with metal with metal bonded cup type wheel and its effects on spherical surface grinding.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.8 no.6
• /
• pp.530-536
• /
• 2016

The number of fabrication shop for spherical type LNG tank is proportional to that of the tank radius to be constructed. Due to limitation of facility investment including building sites, it is practically difficult to fabricate various size tanks with perfectly spherical shape in the yards. The efficient method to be capable of increasing cargo tank volume is to extend vertically the conventional spherical type LNG tank by inserting a cylindrical shell structure. The main purpose of this study is to derive related equations on forces generated on spherical type LNG tank with central cylindrical part under various static loadings in order to establish the simplified analysis method for the initial estimate. In this study, equations on circumferential and meridional force have been derived and verified by relations with the reaction forces per unit length of equator.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.5
• /
• pp.172-177
• /
• 2007

In this paper, spherical aberration and light concentrating efficiency of lens was measured. The measuring system is applying spherical aberration occurrence principal and could measure a temperature at focal plane by using the thermocouple. The sun which is located in infinite distance and could makes parallel ray is used as a illuminant or heat source in experiments. It is confirmed that light concentrating efficiency of optical lens is in inverse proportion to spherical aberration and.

• 한국공간정보시스템학회:학술대회논문집
• /
• 2004.05a
• /
• pp.169-175
• /
• 2004

Researches on spherical shell which is most usually applied have been completed by many investigators already and generalized numerical formula was derived. But the existent researches are limited to those on spherical shell with isotropic or orthotropic roof stiffness, periodic distribution of roof stiffness that can be caused by spherical and latticed roof system is not considered. Therefore, this paper is to develop a structural analysis program to analyze spherical shells that have periodicity of roof stiffness distribution caused by latticed roof of large space structure, grasp buckling characteristics and behavior of structure.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.22 no.3
• /
• pp.207-215
• /
• 2017

The superior performance of the spherical actuator is establishing a new trend in the industry. Spherical actuators can perform multiple degrees-of-freedom (DOF) motions by using only one actuator. Therefore, a multi-DOF device using the spherical actuator can reduce weight and simplify the structure. This paper proposes a new spherical actuator that uses the operational principle of a rotational voice coil motor. The effectiveness of the actuator is verified through 3-D finite element method.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.1
• /
• pp.90-96
• /
• 2013

As the need of electric motor is increased rapidly throughout our society, the various application fields are created and the service market called robot gets expanded as well as the existing industrial market. Out of those, the joint systems such as humanoid that is servo actuator for position control or all fields which require multi-degree of freedom (multi-DOF) require the development of innovative actuator. It is multi-DOF spherical motor that can replace the existing system in multi-DOF operating system. But, multi-DOF spherical motor that has been researched up to date is at the stage which is insufficient in performance or mechanical practicality yet. Thus, first of all the research results and limitation of the previously-researched guide frame-type spherical motors were analyzed and then the feature of double air-gap spherical motor which was devised to complement that was studied. The double air-gap multi-DOF spherical motor is very suitable spherical motor for system applying which requires the multi-DOF operation due to its simple structure that does not require other guide frame as well as performance improvement due to its special shape which has two air-gaps. So, the validity of the study was verified by designing and producing it with 3D-FEM through the exclusive jig for multi-DOF spherical motor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.9
• /
• pp.14-22
• /
• 2015

TIn this paper, a centering method for an unfocused input character using the spherical domain system and the centering character to use the shift invariant feature for the recognition system is proposed. A system for recognition is implemented using the centroid method with coordinate average values, and the results of an above 78.14% average differential ratio for the character features were obtained. It is possible to extract the shift invariant feature using spherical transformation similar to the human eyeball. The proposed method, which is feature extraction using spherical coordinate transform and transformed extracted data, makes it possible to move the character to the center position of the input plane. Both digital and optical technologies are mixed using a spherical coordinate similar to the 3 dimensional human eyeball for the 2 dimensional plane format. In this paper, a centering character feature using the spherical domain is proposed for character recognition, and possibilities for the recognized possible character shape as well as calculating the differential ratio of the centered character using a centroid method are suggested.

• Journal of the Society of Naval Architects of Korea
• /
• v.54 no.5
• /
• pp.393-405
• /
• 2017

This paper deals with the buckling strength of the skirt structure in the spherical LNG carriers. The spherical cargo tank systems consist of spherical tank, skirt, tank cover, pump tower, etc. The skirt supports the spherical cargo tank and is connected with ship hull structure. It is designed to act as a thermal brake between the tank and the hull structure by reducing the thermal conduction from the tank to the supporting structure. It is built up of three parts, upper aluminum part, middle stainless steel part and lower carbon steel part. The 150K spherical LNG carrier was designed and carried out the strength verification under Classification Societies Rule. The design loads due to acceleration, thermal distribution, self-weight and cargo weight were estimated considering requirements of the Class Rule and numerical simulation analyses. Based on the obtained design loads and experienced project data, the initial structure scantling was carried out. To verify the structural integrity, theoretical and numerical analyses were carried out and strength was evaluated aspect of buckling capacity. The results by LR and DNV design code are shown and discussed.

• Journal of Korean Ophthalmic Optics Society
• /
• v.12 no.4
• /
• pp.83-86
• /
• 2007

In this study, a program has been developed to enable a simulation of spherical aberration - originated from a spherical surface and an aspheric surface - via ray tracing and calculation of the degree of spherical aberration. This process has been verified for the variation of spherical aberration generated from ray tracing for aspheric surfaces such as an oval, a parabola, and a hyperbola. By comparing it with the spherical surface, the principle and necessity of the aspheric surface lens design have been understood. In addition, it allows confirming the accuracy of the simulation by developing a ray tracing program in relation to the mirror plane of a parabola.