• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.6
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• pp.515-525
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• 2022

The wireless power transfer (WPT) charging system for AGV depends highly on the coupling conditions due to air gap variation. To attain stable output power with high transfer efficiency under various coupling conditions, a single-stage, DC-DC converter that operates with robustness to changes in air gaps is proposed for the WPT system. The proposed converter is capable of soft switching under the set input voltage (V_in: 380 V_DC), load conditions (0-1 kW), and air gap changes (30-70 mm). In addition, a wide output voltage range (Vo: 39-54 V_DC) can be controlled by varying the link voltage due to the phase control at a fixed switching frequency. Experimental results are verified using a prototype of a 1 kW wireless power charging system.

• Structural Engineering and Mechanics
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• v.91 no.3
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• pp.279-289
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• 2024

The purpose of this study is to represent a useful alternative for the preliminary seismic vulnerability assessment of existing reinforced concrete buildings by introducing a statistical approach employing the binary logistic regression technique. Two different predictive statistical models, namely full and reduced models, were generated utilizing building characteristics obtained from the damage database compiled after 1999 Düzce earthquake. Among the inspected building parameters, number of stories, overhang ratio, priority index, soft story index, normalized redundancy ratio and normalized lateral stiffness index were specifically selected as the predictor variables for vulnerability classification. As a result, normalized redundancy ratio and soft story index were identified as the most significant predictors affecting seismic vulnerability in terms of life safety performance level. In conclusion, it is revealed that both models are capable of classifying the set of buildings being severely damaged or collapsed with a balanced accuracy of 73%, hence, both are able to filter out high-priority buildings for life safety performance assessment. Thus, in this study, having the same high accuracy as the full model, the reduced model using fewer predictors is proposed as a simple and viable classifier for determining life safety levels of reinforced concrete buildings in the preliminary seismic risk assessment.

• Archives of Reconstructive Microsurgery
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• v.20 no.2
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• pp.108-112
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• 2011

Purpose: Gracilis muscle free flap transplantation is chosen in the medium sized soft tissue defect and bone exposure from trauma and chronic osteomyelitis in the lower extremity. We set a study to search for gracilis free flaps to know whether symptoms were cured or recurred in patients that have passed over 10 years from flap transplantation. Materials and Methods: From August 1995 through September 2010, we have performed 28 cases of gracilis muscle free flap in the lower extremities. Ever since no case visited to demand any discomfort, breakdown or recurrence in the flap site on outpatient basis. We made a telephone call to patients or relatives documented in the medical record and only 2 cases visited outpatient department and 9 cases postponed the visit who satisfied with the final result but 17 cases had wrong telephone numbers. Causes, area of lower extremity, recipient vessels in the lower extremity, condition of the donor thigh and overall satisfaction of the flap transplantation in activities of daily living were investigated and written down in the medical record. Results: 11 cases were reviewed after average postoperative 13.7 years. Gracilis muscle flaps were not break down at the recipient site in all cases. The wound of donor thigh wound healed good and overall activities of daily living was satisfied in all cases. Conclusion: Gracilis muscle flaps which had performed and followed up average 13.7 years revealed confident in the medium sized soft tissue defect and bone exposure from trauma and chronic osteomyelitis in the lower extremity.

• Journal of the Korean Wood Science and Technology
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• v.44 no.6
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• pp.842-851
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• 2016

The objective of this study was to improve physical and mechanical properties of soft-inner part of oil palm trunk (S-OPT) after impregnation with phenol formaldehyde (PF) resin and densification by close system compression (CSC) method. Effect of different methods of PF resin impregnation (i.e., no vacuum-pressure, vacuum, and vacuum-pressure) was evaluated. The results showed that PF resin impregnation and CSC significantly improved the physical and mechanical properties of S-OPT up to: (1) 176% in density; (2) 309% in modulus of rupture (MOR); (3) 287% modulus of elasticity (MOE); and (4) 191% in the compressive strength. Physical and mechanical properties of S-OPT showed their best performances when PF resin impregnated with vacuum-pressure method as shown by higher weight gain, density, MOR, MOE, compressive strength, and lower recovery of set due to better penetration of PF resin into S-OPT. Combining PF resin impregnation and densification by CSC method could be a good method to improve physical and mechanical properties of S-OPT.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.3
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• pp.149-154
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• 2017

The MCT-Adaboost algorithm chooses an optimal set of features in each rounds. On each round, it chooses the best feature by calculate minimizing error rate using feature index and MCT kernel distribution. The involved process of weak classification executed by a hard decision. This decision occurs some problems when it chooses ambiguous kernel feature. In this paper, we propose the modified MCT-Adaboost classification using soft decision. The typical MCT-Adaboost assigns a same initial weights to each datum. This is because, they assume that all information of database is blind. We assign different initial weights with our propose new algorithm using some statistical properties of involved features. In experimental results, we confirm that our method shows better performance than the traditional one.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.907-917
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• 2014

When conducting excavations after burying the soft ground, even if the retaining walls are installed, failure often occurs within backfill. In order to minimize the occurrences of failures, model test was performed after the installation of stabilizing piles to investigate the stabilizing effects. The model chamber is set up with clay foundation reinforced with and without stabilizing piles. During the excavation of clay foundation, the subsidence, pore water pressure, and soil pressure along the excavation were measured. As a result of the model test, the increase of excavation levels and the reduction of subsidence of back ground were observed with the stabilizing piles, compared to those without the stabilizing piles. The installation of stabilizing piles does not influence the pore water pressure change, but induces less subsidence rate. In addition, the depth of excavation has a significant effect on the back ground and it was evaluated that the maximum subsidence occurs as it is closer to the excavation point.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.709-730
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• 2017

To address the challenge of unprecedented growth in mobile data traffic, ultra-dense network deployment is a cost efficient solution to offload the traffic over some small cells. The overlapped coverage areas of small cells create more than one candidate access points for one mobile user. Signal strength based user association in IEEE 802.11 results in a significantly unbalanced load distribution among access points. However, the effective bandwidth demand of each user actually differs vastly due to their different preferences for mobile applications. In this paper, we formulate a set of non-linear integer programming models for joint user association control and user demand guarantee problem. In this model, we are trying to maximize the system capacity and guarantee the effective bandwidth demand for each user by soft-association control with a software defined network controller. With the fact of NP-hard complexity of non-linear integer programming solver, we propose a Kernighan Lin Algorithm based graph-partitioning method for a large-scale network. Finally, we evaluated the performance of the proposed algorithm for the edge users with heterogeneous bandwidth demands and mobility scenarios. Simulation results show that the proposed adaptive soft-association control can achieve a better performance than the other two and improves the individual quality of user experience with a little price on system throughput.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.23 no.2
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• pp.27-32
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• 2017

Background: The purpose of this study was to compare the effects of IASTM and static stretching techniques on ankle joint range of motion (ROM), static foot pressure. Methods: Twenty four subjects with gastrocnemius shortness participated in this study. The subjects were assigned randomly to one of two groups: The soft tissue mobilization technique (IASTM) group received intervention using a IASTM instrument for two minutes, and the stactic stretching group performed self stretching for 30 seconds, four times. The ROM of the ankle joint was measured by active ankle dorsi-flexion test, and a TPScan was utilized to collect the plantar foot pressure. This experiment was performed by two physical therapists. The significant level was set at ${\alpha}=.05$. Results: The results were as follows: 1) The ROM of the ankle joint and was significantly increased in both groups. 2) Plantar foot pressure was no significant in both groups. 3) There were no significant differences between the IASTM group and static stretching group for any variable. Conclusions: The results of this study suggest that static stretching is an effective and easy technique for restoring proper muscle length in subjects with gastrocnemius shortness. We recommend that static stretching technique be used for treat gastrocnemius shortness in clinical setting and home program.

• Journal of Fashion Business
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• v.19 no.2
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• pp.103-117
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• 2015

The purpose of this study was to examine the uniform image of Korean herbal cosmetic brands amongst Korean and Chinese consumers. This study would enable us to explore a BI strategy to enhance international competitiveness of Korean herbal cosmetics brands. The results were as follows. The key words of BI pursued by Sulwhasoo were dignified, novel, graceful, soft, gaily, natural, Korean, modern, and international. Korean people felt that the uniform was graceful and soft, which accorded with Sulwhasoo BI, but also it was trite and dingy, indicating a negative and opposing image. On the other hand, Chinese people felt that the uniform was dignified, novel, graceful, natural, modern, and international, indicating that it matched with Sulwhasoo BI. In The History of Whoo, the key words of BI pursued by the brand were precious, soft, gorgeous, gaily, and natural. The Koreans felt that the uniform was intelligent, and decent, but conversely, it was also austere and dingy, indicating a negative image. The Chinese felt that the uniform was common, hard, austere, dingy, and unnatural, indicating an opposing image to BI. Finally, a uniform design was developed to improve on its problems, establish The History of Whoo's brand identity, and its brand image. First of all, 'The Quintessence : noble passion' was set up as a developmental concept. The textiles, clothing, and accessories were designed using the symbolic elements from The History of Whoo as a motif. Uniforms were developed for spring, fall, and summer.

• Journal of the Korean Geotechnical Society
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• v.34 no.2
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• pp.5-17
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• 2018

In this study, the in-situ stress, strength and stress-strain characteristics with shear parameters (UU, CU, ${\bar{CU}}$) are analytically evaluated and the stability analyses are carried out under loading/unloading conditions. The in-situ stress and the stress-strain behaviour may become different according to input shear parameters in finite element analyses with construction step, Especially, if the internal friction angle in Mohr-Coulomb model is set to zero, the in-situ stress and the stress-strain behaviour might not be properly predicted. The results from CU parameter of total stress analysis have no significant difference with the results from CU of effective stress analysis. Therefore, in the numerical analysis for soft ground, CU parameters can be applied to predict in-situ stress and stress-strain behaviors. In addition, the calculation method was proposed to determine the shear parameter of Mohr-Coulomb model, which is corresponding to the shear strength equivalent to that of in-situ soil.