• Current Optics and Photonics
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• v.7 no.6
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• pp.597-607
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• 2023

Volumetric 3D displays generate voxels to enable users to watch three-dimensional virtual objects from various angles, and they have a significant advantage over other types of 3D displays in terms of realism and the absence of vergence-accommodation conflict (VAC). By virtue of these advantages, various volumetric 3D display technologies incorporating novel approaches have been introduced competitively. As a result, the conventional classification criteria for volumetric 3D technology often fall short in categorizing these innovative methods. In this study, we present an improved classification framework capable of accommodating these new technologies. We expect that a new classification may offer some intuition to identify areas of technical deficiency and contribute to improving the technology.

• Journal of Drive and Control
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• v.17 no.2
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• pp.28-37
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• 2020

It is difficult to analytically derive the relationship among volumetric displacement, flowrate, torque, and rotation speed regarding an instantaneous position of gerotor hydraulic pumps/motors. This can be explained by the geometric shape of the rotors, which is highly complicated. Herein, an analytical method for the instantaneous torque, rotation speed, flowrate, and volumetric displacement of a pump/motor is proposed. The method is based on two physical concepts: energy conservation and torque equilibrium. The instantaneous torque of a pump/motor shaft is determined for the posture of rotors from the torque equilibrium. If the torque equilibrium is combined with the energy conservation between the hydraulic energy of the pump/motor and the mechanical input/output energy, the formula for determining the instantaneous volumetric displacement and flowrate is derived. The numerical values of the instantaneous volumetric displacement, torque, rotation speed, and flowrate are calculated via the MATLAB software programs, and they are illustrated for the case in which inner and outer rotors rotate with respect to fixed axes. The degrees of torque fluctuation, speed fluctuation, and flowrate fluctuation can be observed from their instantaneous values. The proposed formula may provide a better understanding of the design or analysis process of gerotor pumps/motors.

• Journal of Power System Engineering
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• v.9 no.2
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• pp.19-25
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• 2005

Empirical experiments have been undertaken to investigate the effects of Intake Pulsating Flow on volumetric efficiency in a diesel engine. Waves occurs in the manifolds of engine owing to the periodic nature of the induction and exhaust processes caused by piston motion. During induction process, as waves travel both directions, they are reflected and interacted each other and pressure waves are transmitted through it. Hence, the flow become more complex and unsteady flow. These pressure waves act upon intake pulsating flow and affects on volumetric efficiency. In this paper the effects of change in length of induction pipes and wide range of engine speed on volumetric efficiency was examined and evaluated. It was found that volumetric efficiency was affected by intake pulsating flow with engine speed and the pipe length. The results obtained were considered by adopting a theory of wave action.

• Structural Engineering and Mechanics
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• v.26 no.2
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• pp.127-150
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• 2007

The objective of this paper is to develop a finite element procedure for predicting the compressive strength and ultimate axial strain of Carbon Fiber Reinforced Plastics (CFRP) confined circular concrete columns and to study the effective parameters of confinement efficiency for helping design of CFRP retrofit technology. The behavior of concrete confined with CFRP is studied using the nonlinear finite element method. In this paper, effects of column size, CFRP volumetric ratio and plain concrete strength are studied. The confined concrete nonlinear constitutive relation, concrete failure criterion and stiffness reduction methodology after concrete cracking or crushing are adopted. First, the finite element model is verified by comparing the numerical solutions of confined concrete with experimental results. Then the effects of column size, CFRP volumetric ratio and plain concrete strength on the peak strength and ductility of the confined concrete are considered. The results of parametric study indicate that the normalized column axial strength increases with increasing CFRP volumetric ratio, but without size effect for columns with the same CFRP volumetric ratio. As the same, the increase in column ductility depends on CFRP volumetric ratio but without size effect for columns with the same CFRP volumetric ratio.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.327-333
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• 2015

To measure the dimensional stability of three softwoods by vacuum pressurization of water soluble melamine-formaldehyde (MF) resin impregnation process, properties of resin treated compressed woods (compregs) were measured after impregnating the water soluble MF resin into three coniferous wood species for different impregnation times and resin concentrations. As the resin concentration was higher and impregnation time was longer, coefficients of volumetric shrinkage and anti-volumetric swelling efficiency increased, but coefficients of volumetric swelling, anti-volumetric swelling efficiency and absorption decreased. Also, weight percent gain increased remarkably as the resin concentration was high, but there was no uniform relationship with impregnation time.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.849-857
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• 2023

Volumetric Studio is catalyzing the expansion of the XR content market. Consequently, there is a rising demand for in-depth research on volumetric capture technology. This research delves into the methodology and outcomes of capturing dancers' movements in the form of 3D video images. Furthermore, this research examines the practical applications of volumetric capture technology by assessing the infrastructure and operational workflow of the studio specializing in this domain, aiming to derive significant findings. Notably, this research highlights constraints associated with video image distortion and extended rendering durations within Volumetric Studio system.

• The Journal of the Korea Contents Association
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• v.8 no.7
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• pp.85-92
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• 2008

Meshes are the most appropriate data structures for representing 3D geometries. Surface meshes have been frequently used for representing 3D geometries, which only samples data on the surfaces of the given 3D geometries. Thanks to the improvements of computing powers, it is required to develop more complicated contents which utilize the volumetric information of 3D geometries. In this paper, we introduce a novel volumetric mesh libraries based on the half-face data structure, called OpenVolMesh, and describe its designs and implementations. The OpenVolMesh extends the OpenMesh, which is one of the most famous mesh libraries, by supporting volumetric meshes. The OpenVolMesh provides the generic programming, dynamic allocations of primitive properties, efficient array-based data structures, and source-level compatibility with OpenMesh. We show the usefulness of the OpenVolMesh in the developments of 3D volumetric contents with prototypic implementations such as volumetric mesh smoothing and CW-cell decompositions.

• Journal of Korean Neurosurgical Society
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• v.45 no.6
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• pp.329-335
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• 2009

Objective : Determining language lateralization is important for the presurgical evaluation of patients with medically intractable epilepsy. The Wada test has been the gold standard for lateralization of language dominance before epilepsy surgery. However, it is an invasive test with risk, and have some limitations. Methods : We compared the volumetric analysis with Wada test, and studied the clinical potential of volumetric analysis to assess language laterality in large surgical candidates with temporal lobe epilepsy (TLE). To examine the efficacy of volumetric analysis to determine language lateralization during presurgical evaluation, we compared the volumetric analysis of the bilateral planum temporale with the results of Wada test in 59 patients with chronic intractable TLE (rTLE, n=32; lTLE, n=27) who underwent epilepsy surgery. We measured the gray matter volumes of planum temporale (PT) of each patients using the VoxelPlus2 program (Mevisys, Daejeon, Korea). Results : Overall congruence of the volumetric analysis with the Wada test was 97.75% in rTLE patients and 81.5% in lTLE patients. There were more significant leftward asymmetry of the PT in rTLE patients than lTLE patients. In lTLE patients, relatively high proportion (37%) of the patients showed bilateral or right hemispheric language dominance. Conclusion : These results provide evidence that the volumetric analysis of the PT could be used as an alternatives in language lateralization. Also, the results of the Wada test suggested that there was considerable plasticity of language representation in the brains of patients with intractable TLE and it was associated with an earlier age of brain injury.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.7-13
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• 2010

To satisfy the needs on fuel economy and engine performance, continuous variable valve lift systems are applying to engines. In the CVVL system, fuel economy can be improved by reducing pumping loss during the induction process, and engine performance can be also improved by controlling volumetric efficiency and the residual gas fraction. Because the residual gas fraction directly affects volumetric efficiency, engine performance, combustion efficiency and emissions in SI engines, controlling residual gas fraction is one of the important things in engine development process. This analysis investigates the residual gas fraction and volumetric efficiency with changes of intake valve lifts and intake valve timings. In this study, unsteady state solutions were solved during exhaust and induction processes. Results show variation of the residual gas fraction and volumetric efficiency by changing intake valve timing and lift. Decreasing intake valve lift leads to increase the residual gas fraction and to decrease volumetric efficiency.

• Journal of Drive and Control
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• v.11 no.4
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• pp.15-24
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• 2014

It is difficult to analytically derive a volumetric displacement formula for a gerotor hydraulic motor due to the complexity of the geometric shape of its gear lobes. This work proposes an analytical method for the volumetric displacement, a relatively easy method based upon two physical concepts: conservation between hydraulic energy and mechanical shaft energy, and torque equilibrium for the rotor's motion. The first research using these concepts was conducted on inner and outer rotors rotating with respect to each rotor axis. This work represents the second report conducted on an inner rotor revolving as a planetary motion on the stationary outer rotor. The formula equations regarding the volumetric displacement and flow rate are derived, and the proposed formula about the volumetric displacement is proven to be the same as another analytical displacement formula: the so-called vane length method. From the formula, volumetric displacement is calculated for an example geometry of the gear lobes. The resultant displacement is confirmed to be the same as the value calculated from the chamber volume method. The proposed analytical formula can be utilized in the analysis and design of gerotor hydraulic motors. Because it is based on torque equilibrium, this formula can provide a better understanding of torque performance, such as torque ripple, in designing a gerotor type motor.