• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.5
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• pp.907-921
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• 2021

This study aims to predict causal relationships between experience economy, perceived flow, and continuous use intention in the mixed reality (MR) environment. A virtual fitting mirror with two modes (i.e., avatar and self-image) was selected for this study. A total of 200 samples was obtained in two sample frames: virtual fitting users in avatar mode (group 1, n = 119) and self-image mode (group 2, n = 81). The results showed that the experience economy consists of entertainment, education, esthetic, and escapism. The entertainment and esthetic experiences had positive effects on perceived flow, leading to continuous use intentions. For avatar mode, the entertainment and esthetic experiences had positive effects on continuous use intentions through the mediating effect of flow; and the education experience had a positive effect on the continuous intentions to use the MR technology. For self-image mode, the flow mediated the effect of entertainment on continuous use intentions, whereas education and escapism directly affected the intention to use the MR technology. The paper also discusses the theoretical and managerial implications of using MR technologies in fashion retailing.

• Design & Manufacturing
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• v.13 no.3
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• pp.12-18
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• 2019

Fluid jet polishing is a method of jetting a fluid to polish a concave or free-form surface. However, the fluid jet method is difficult to form a stable polishing spot because of the lack of concentration. In order to solve this problem, MR fluid jet polishing system using an abrasive mixed with an MR fluid whose viscosity changes according to the intensity of a magnetic field is under study. MR fluid jet polishing is not easy to formulate for precise optimal conditions and material removal due to numerous fluid compositions and process conditions. Therefore, in this paper, quantitative data on the factors that have significant influence on the machining conditions are presented using various simulations and the correlation studies are conducted. In order to verify applicability of the fabricated MR fluid jet polishing system by nozzle diameter, the flow pattern and velocity distribution of MR fluid and polishing slurry of MR fluid jet polishing were analyzed by flow analysis and shear stress due to magnetic field changes was analyzed. The MR fluid of the MR fluid jet polishing and the flow pattern and velocity distribution of the polishing slurry were analyzed according to the nozzle diameter and the effects of nozzle diameter on the polishing effect were discussed. The analysis showed that the maximum shear stress was 0.45 mm at the diameter of 0.5 mm, 0.73 mm at 1.0 mm, and 1.24 mm at 1.5 mm. The cross-sectional shape is symmetrical and smooth W-shape is generated, which is consistent with typical fluid spray polishing result. Therefore, it was confirmed that the high-quality surface polishing process can be stably performed using the developed system.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.127-130
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• 1997

Phase-contrast(PC) methods have been used for quantitative measurements of velocity and volume flow rate. In addition, phase contrast cine magnetic resonance imaging (MRI) combines the flow dependent contrast of PC MRI with the ability of cardiac cine imaging to produce images throughout the cardiac cycle. In this method, the through-plane velocity has been encoded generally. However, the accuracy of the flow data can be reduced by the effect of flow direction, finite slice thickness, resolution, pulsatile flow pattern, and so on. In this study we calculated the error caused by misalignment of tomographic plane and flow directon. To reduce this error and encode the velocity for more complex flow, we suggested 3 directional velocity encoding method.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.223-233
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• 2019

This study aimed to explore YouTube subscribers' uses and gratification through PLS path modeling. Especially, we identified the types of use motives grounded on ritualized (MR) and instrumental (MI) use motives; and then showed two motives have an effect on satisfaction directly and indirectly through mediating of flow. We employed PLS path modeling to analyze structural causalities among the constructs. We found all of the presented hypotheses are supported respectively. Two motives (MR and MI) had an effect on flow and satisfaction. Flow also had an effect on satisfactions. Namely, satisfaction was explained directly and indirectly, through mediated with flow, by MR and MI. Finally, we presented implications of findings and suggestion for future study.

• Korean Journal of Digital Imaging in Medicine
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• v.15 no.1
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• pp.27-31
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• 2013

Perfusion MR imaging is how to use exogenous and endogenous contrast agent. Exogenous perfusion MRI methods which are dynamic susceptibility contrast using $T2^*$ effect and dynamic contrast-enhanced using T1 weighted image after injection contrast media. An endogenous perfusion MRI method which is arterial spin labeling using arterial blood flow in body. In order to exam perfusion MRI in human, technical access are very important according to disease conditions. For instance, dynamic susceptibility contrast is used in patients with acute stroke because of short exam time, while dynamic susceptibility contrast or dynamic contrast enhancement provides the various perfusion information for patients with tumor, vascular stenosis. Arterial spin labeling is useful for children, women who are expected to be pregnant. In this regard, perfusion MR imaging is required to understanding, and the author would like to share information with clinical users

• Proceedings of the KOSOMBE Conference
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• v.1993 no.11
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• pp.23-26
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• 1993

In MR functional imaging, it is shown that the signal change during photic activation is composed of two terms, i.e. the inflow effect and the susceptibility effect. Relatively the inflow effect affects the data obtained by CGE on the condition of short $T_E$(15ms) and large $\alpha$(90degree). The susceptibility effect, however, mainly contributes to the data on the condition of large $T_E$(35ms) and small $\alpha$(30degree). In this apper, we will discriminate the susceptibility effect for the intermingled data affected both flow effect and susceptibility effect. Finally susceptibility only functional imaging is proposed by using TRFGE.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.96-97
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• 1998

3D TOF MR Angiography is able to obtain thinner slice thickness, higher SNR, therefore higher spatial resolution than 2D TOF MR Angiography. Since it uses longer TR than 2D TOF MRA to allow stronger in-flow effect, the background tissue may not be fully saturated. Thus background tissue signal can be further suppressed by MTS(Magnetization Transfer Saturation). Flow-compensation was accomplished by GMN(Gradient Moment Nulling), and tracking saturation was used to suppress vein signal. The different flow signal at the entry of the slab and output of the slab can be compensated by TONE(Tilted Optimized Non-saturating Excitation) RF pulse.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.243-251
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• 1997

In this paper, we have reported two interesting flow effects arising in the TRFGE sequence using water flow phantom. First, we have shown that the TRFGE sequence is indeed not affected by "in-flow" effect from the unsaturated spins flowing into the imaging slice. Second, the enhancement of "in-plane flow" signal in the readout gradient direction was observed when the TRFGE sequence was used without flow compensation. These two results have many interesting applications in MR imaging other than fMRI. Results obtained were also compared with the results obtained by the conventional gradient echo(CGE) imaging. Experiments were performed at 4.7T MRI/S animal system (Biospec, BRUKER, Switzerland). A cylindrical phantom was made using acryl and a vinyl tube was inserted at the center(Fig. 1). The whole cylinder was filled with water doped with $MnCl_2$ and the center tube was filled with saline which flows in parallel to the main magnetic field along the tube. Tailored RF pulse was designed to have quadratic ($z^2$) phase distribution in slice direction(z). Imaging parameters were TR/TE = 55~85/10msec, flip angle = $30^{\circ}$, slice thickness = 2mm, matrix size = 256${\times}$256, and FOV= 10cm. In-flow effect : Axial images were obtained with and without flow using the CGE and TRFGE sequences, respectively. The flow direction was perpendicular to the image slice. In-plane flow : Sagittal images were obtained with and without flow using the TRGE sequence. The readout gradient was applied in parallel to the flow direction. We have observed that the "in-flow" effect did not affect the TRFGE image, while "in-plane flow" running along the readout gradient direction enhanced the signal in the TRFGE sequence when flow compensation gradient scheme was not used.

• Annals of Clinical Neurophysiology
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• v.4 no.1
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• pp.38-43
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• 2002

Background & Purpose : Dynamic susceptibility contrast MR imaging, one method of perfusion MRI, was developed to define cerebral hemodynamic status with good anatomical resolution. The authors investigated hemodynamic parameters using this imaging method, in an effort to identify hemodynamic changes on the remote crossed cerebellum of patients with a supratentorial infarct. Methods : Dynamic susceptibility contrast MR imaging was performed in 15 patients with only unilateral supratentorial infarcts. Imaging was obtained at the anatomic level of the cerebellum. rCBF, rCBV, MTT and TP were determined over both cerebellar hemispheres of interest. Results : The rCBF and rCBV values of the contralateral cerebellar hemisphere were significantly more decreased than those of the ipsilateral cerebellar hemisphere in 12 patients(p=0.028, 0.033). MTT and TP values of the contralateral and ipsilateral cerebellar hemispheres didn't reveal any differences(p=0.130, 0.121). Conclusions : The results of this work suggest that the region which are remote from the ischemic brain lesion shows no changes of MTT or TP but show decrease of rCBF and rCBV, mean to diaschisis, it also demonstrates that perfusion MRI is an easily available method to evaluate the hemodynamic status of the brain.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.135-140
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• 2023

VR animation allows you to see 360-degree screen production that cannot be seen in existing animation production while being located in the space within the animation. <Goodbye Mr Octopus>, a VR animation produced in 2020, was selected at the 77th Venice Film Festival as an immersive short film. This is the story of an adolescent girl, Stella, who is celebrating her 16th birthday, and her conflict with her strict father is resolved through a letter from her mother. It is a narrative composed of a total of 11 scenes, and in each scene, new directing elements of VR video grammar, such as gaze induction, time flow, and space conversion directing, were analyzed. Gaze-inducing directing minimized the inconvenience of 360-degree gaze, and time and space conversion directing was analyzed as an effect of increasing the audience's immersion according to narrative events.