• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.429-441
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• 2011

In the southeast coastal zone of Yellow Sea, the tide characteristics showing ebb-dominant tide and tidal flow were confirmed by analysis of observed tide and tidal currents. Physical factors generating asymmetric tide were reviewed. Influence of bottom shear stress, tidal flat, and nonlinear terms in shallow water equations was investigated by two-dimensional tide modeling. The model results gave good agreements with observed tides, but the amplitude of simulated $M_4$ tide was less than that of observed tide. The tidal flats existing in the study area widely have great effect on the generation of nonlinear tide. The M4 tide is mainly generated near the tidal flats. The deletion of tidal flats prevents the production of the M4 tide. We can conclude that the wide tidal flats is a primary cause of tide asymmetry in the study area.

• Imaging Science in Dentistry
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• v.38 no.4
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• pp.203-208
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• 2008

Purpose : The purpose of this study was to develop a system for the measurement and simulation of the TMJ movement and to analyze the mandibular movement quantitatively. Materials and Methods : We devised patient-specific splints and a registration body for the TMJ movement tracking. The mandibular movements of the 12 subjects with facial deformity and 3 controls were obtained by using an optical tracking system and the patient-specific splints. The mandibular part was manually segmented from the CT volume data of a patient. Three-dimensional surface models of the maxilla and the mandible were constructed using the segmented data. The continuous movement of the mandible with respect to the maxilla could be simulated by applying the recorded positions sequentially. Trajectories of the selected reference points were calculated during simulation and analyzed. Results : The selected points were the most superior point of bilateral condyle, lower incisor point, and pogonion. There were significant differences (P<0.05) between control group and pre-surgical group in the maximum displacement of left superior condyle, lower incisor, and pogonion in vertical direction. Differences in the maximum lengths of the right and the left condyle were 0.59${\pm}$0.30 mm in pre-surgical group and 2.69${\pm}$2.63 mm in control group, which showed a significant difference (P<0.005). The maximum of differences between lengths of the right and the left calculated during one cycle also showed a significant difference between two groups (P<0.05). Conclusion : Significant differences in mandibular movements between the groups implies that facial deformity have an effect on the movement asymmetry of the mandible. (Korean J Oral Maxillofac Radiol 2008; 38 : 203-8)

• Journal of Convergence for Information Technology
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• v.12 no.4
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• pp.103-110
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• 2022

Online transactions are more familiar in various fields due to the development of the ICT and the increase in trading platforms. In particular, the amount of transactions is increasing due to the increase in used transaction platforms and users, and reliability is very important due to the nature of used transactions. Among them, the used car market is very active because automobiles are operated over a long period of time. However, used car transactions are a representative market to which information asymmetry is applied. In this paper presents a DID-based transaction model that guarantees reliability to solve problems with false advertisements and false sales in used car transactions. In the used car transaction model, sellers only register data issued by the issuing agency to prevent false sales at the time of initial sales registration. It is authenticated with DID Auth in the issuance process, it is safe from attacks such as sniping and middleman attacks. In the presented transaction model, integrity is verified with VP's Proof item to increase reliability and solve information asymmetry. Also, through direct transactions between buyers and sellers, there is no third-party intervention, which has the effect of reducing fees.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.6
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• pp.133-145
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• 2023

This paper examines whether investors have adapted to the venture capital(VC) investment style. VC firms invest in privately held companies and generate returns by selling them after the lock-up period expires. We analyze the impact on stock prices before and after the lock-up period expiration, and compare the Cumulative Abnormal Return(CAR) between the past period(2015-2017) and the recent period(2020-2022) to investigate the effect of the second venture boom. The main findings are as follows. First, unlike in the past, stock price returns around the lock-up period expiration have been lower than the KOSDAQ index in recent years. Second, the impact on stock prices is significant for both 1-month and 12-month lock-up periods. Specifically, it is confirmed that stocks held by venture capital and professional investors with a 1-month lock-up period respond in advance to their information after the second venture boom. Finally, we find that there is a difference in CAR depending on whether or not the company received VC investment after the second venture boom. Based on our findings, we suggest that VC firms need to revise their exit strategies to improve performance. This includes finding ways to reduce information asymmetry and fees, as well as developing strategies to mitigate market volatility. Additionally, the current lock-up period for VCs should be reconsidered as it may increase the risk of stock price decline. We recommend that the government revise the scope and duration of lock-up periods to protect investors after IPO.

• Journal of Korean Medicine Rehabilitation
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• v.24 no.1
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• pp.83-92
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• 2014

Objectives To evaluate the clinical usefulness between muscle energy techniques (MET) and transcutaneous electrical nerve stimulator (TENS), we performed both on elector spinae muscle of acute low back pain patients. Methods After performing MET and TENS, we compared both in terms of electrical activity. We performed MET or TENS on elector spinae muscle of acute low back pain patients in each group (n=15,15). After performing MET or TENS, we analyzed root mean square (RMS), median edge frequency (MEF) and asymmetry index (AI). Results 1. After performing MET on elector spinae muscle of acute low back pain patients, RMS was significantly decreased compared with before (p<0.005). 2. After performing TENS on elector spinae muscle of acute low back pain patients, RMS was significantly decreased compared with before (p<0.005). 3. After performing MET on elector spinae muscle of acute low back pain patients, asymmetric index was significantly decreased compared with before (p<0.05). Conclusions According to above results, performing MET on elector spinae muscle of acute low back pain patients has effect in terms of RMS and asymmetric index. And performing TENS on elector spinae muscle of acute low back pain patients also has similar effect in terms of RMS but has not in terms of asymmetric index.

• The korean journal of orthodontics
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• v.21 no.2 s.34
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• pp.325-340
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• 1991

There are evidences that occlusal splint therapy is critical to diagnose hidden akeleto-occlusal disharmonies in malocclusion patients and capable of enhancing stability after orthodontic treatment. In addition, evidences have implicated occlusal splint therapy in condylar positional changes during TMJ disorder treatment. In view of these evidences, this study was performed to investigate the effect of occlusal splint therapy on condylar positional changes in malocclusion patients and the possible clinical application of the occlusal splint as an additional orthodontic tool. For this study, 8 Angle's Class I malocclusion patients, who had centric occlusion-centric relation discrepancy within 1.0 mm and had no clinical symptoms of TMJ disorder, were selected as control group. And 22 malocclusion patients who had centric occlusion-centric relation discrepancy over 1.0 mm were selected and subdivided as Class I Malocclusion group, Class II div. 1 malocclusion group, Class II div. 2 malocclusion group, Open bite group, and Mandibular asymmetry group. For each subject the occlusal splint with mutually protected type of occlusal scheme was applied for 3 months. Condylar positions in centric relation and centric occlusion were measured using Panadent articulators and Panadent condylar position indicator (CPI) before and after occlusal splint therapy. On the basis of this study, the following conclusions might be drawn: 1, In control group, Class II div. 2 malocclusion group, and mandibular assymetry group, there were no significant differences in condylar positions before and after occlusal splint therapy. 2. In Class I malocclusion group, condyles were moved $0.27{\pm}0.45mm$ forward (p < 0.05) and $0.98{\pm}0.25mm$ upward (p < 0.01) after occlusal splint therapy. 3. In Class I malocclusion group, condyles were moved $0.24{\pm}0.21mm$ backward (p < 0.05) and $1.01{\pm}0.33mm$ upward (p < 0.01) after occlusal splint therapy. 4. In open bite group, condyles were moved $1.24{\pm}0.30mm$ upward (p < 0.01) after occlusal splint therapy. 5. In both control and experimental groups, there were no significant differences in lateral condylar positions before and after occlusal splint therapy.

• Journal of Energy Engineering
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• v.19 no.3
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• pp.163-170
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• 2010

The objective of this study is to investigate the combustion characteristics of dual type of sintering burner as a function of design parameters using lab-scale sintering burner through experimental and numerical approaches. Combustion characteristics were evaluated by the radical method. The numerical model was verified as a temperature using R type of thermocouple at the bed surface. The effect of nozzle distance and angle were performed through the CFD analysis, and the comparison of burner types. As a results, dual type burner has more wider and uniform flame distribution than single type burner. Asymmetry and 45 degree angle condition have been suggested as an optimal condition for the ignition of the sintering bed surface.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.61-64
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• 2011

Purpose: The purpose of this study was to design the finite model eye with GRIN lens similar to actual eye, which considered the effect of iris eccentricity on eyes. Methods: By using the finite model eye with Radial GRIN and Spherical GRIN, which were designed previously, the location of iris was eccentrically located by 0.5 mm in the direction of nose to show the same eye as actual one. For ray trace and design, Code V program of Optical Research Associates (ORA) was adopted. Results: Designed model eye was compared to actual eye depending on iris eccentricity and the model eye which showed reduced value was corrected according to actual eye to design the finite model eye. Conclusions: Ocular optical systems considered the point that iris was a rotational asymmetry and designed the finite model eye with GRIN lens, which was similar to actual eye, by considering the effect of iris eccentricity on eye.

• Environmental and Resource Economics Review
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• v.13 no.2
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• pp.175-194
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• 2004

Volumes of research have been implemented to estimate and predict the oil price. These models, however, fail in accurately predicting oil price as a model composed of only a few observable variables is limiting. Unobservable variables and news that have been overlooked in past research, yet have a high likelihood of affecting the oil price. Hence, this paper analyses the news impact on the price. The standard GARCH model fails in capturing some important features of the data. The estimated news impact curve for the GARCH model, which imposes symmetry on the conditional variances, suggests that the conditional variance is underestimated for negative shocks and overestimated for positive shocks. Hence, this paper introduces the asymmetric or leverage volatility models, in which good news and bad news have different impact on volatility. They include the EGARCH, AGARCH, and GJR models. The empirical results showed that negative shocks introduced more volatility than positive shocks. Overall, the AGARCH and GJR were the best at capturing this asymmetric effect. Furthermore, the GJR model successfully revealed the shape of the news impact curve and was a useful approach to modeling conditional heteroscedasticity.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.8 no.1
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• pp.51-56
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• 2010

Purpose : This study identifies the effect of ankle-taping on limb asymmetry, postural sway and lumbar flexibility. Ankle-taping was applied for participants of this study and the results were compared to the control group. Methods : This study targets 46 adults, in which 25 composed the test group and 21 composed the control group. All participants were interviewed. For the test group, inflexible tapes of 5mm width were applied as designed by Danaka Nobudaka while the tapes for the control group were arranged in a symmetric direction to the direction of the test group. Postural balance was measured using Mediance (Human Tech Inc, Korea) and to identify lumbar flexibility, the trunk flexion is targeted. Results : 1. The postural inclination of both the groups decreased, but a statistically significant difference is not found (p>0.05). 2. Both the groups increased, but no statistically significant difference is found (p>0.05). 3. Both the groups increased, and a statistically significant change is found (p<0.05). Conclusion : As demonstrated in the results above, ankle taping is effective for lumbar flexibility as well as stability of ankle joints regardless of the direction of taping. It also suggests that ankle taping is helpful for health management of athletes and the public. However, as the results are limited in that they were obtained 10 minutes after taping, it is hoped that further studies will follow.