• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.4
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• pp.425-431
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• 2015

Based on a bond-based peridynamics theory for dynamic crack propagation problems, this paper presents a design sensitivity analysis and optimization method. Peridynamics has a peculiar advantage over the existing continuum theory in the mathematical modelling of problems where discontinuities arise. For the design optimization of the crack propagation problems, a non-shape design sensitivity is derived using the adjoint variable method. The obtained adjoint sensitivity of displacement and strain energy turns out to be very accurate and efficient compared to the finite different sensitivity. The obtained design sensitivities are futher utilized to optimally control the position of bifurcation point in the design optimization of crack propagation in a plate under tension. A numerical experiment demonstrates that the optimal distribution of material density could delay the position of bifurcation.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.492-497
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• 1994

Extracts of 43 species of plants were tested for their insecticidal and acaricidal activities against six species of insect pests and one mite species. The methanol extract of Ginkgo biloba leaves selectively was found to have potent insecticidal activity against Nilaparvata lugens (Stal), whereas steam distillate of Thujopsis dolabarata var. hondai sawdust showed potent insecticidal activities with a broad spectrum. The methanol extract of Pinus densiflora leaves and steam distillate of T. dolabrata var. hondai sawdust exhibited potent activities against Tetranychus urticae (Koch).

• Applied Biological Chemistry
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• v.37 no.6
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• pp.503-508
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• 1994

Methanol extracts from 45 species of oriental medicinal plants belonging to 17 families were subjected to a screening test for their larvicidal and antifeeding activities against two species of lepidopteran larvae, diamondback moth (Plutella xylostella L.) and tobacco cutworm (Spodoptera litura F.) by a leaf-dipping method. At a concentration of 8,000 ppm, methanol extract of Corydalis turrschaninovii roots only was found to have potent larvicidal activity against S. litura. At 5,000 ppm, strong antifeeding activity against both larvae was observed from the extracts of Clerodendron trichotomum, C. trichotomum var. esculentum, Inura helenium, Arctium lappa, Artemisia messerschmidtiana, Anthriscus sylvestris, Angelica dahurica, and C. turrschaninovii.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.3
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• pp.214-222
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• 2015

The superiority of gallium nitride FET (GaN FET) over silicon MOSFET is examined in this paper. One of the outstanding features of GaN FET is low reverse-recovery charge, which enables continuous conduction mode operation of totem-pole bridgeless boost power factor correction (PFC) circuit. Among many bridgeless topologies, totem-pole bridgeless shows high efficiency and low conducted electromagnetic interference performance, with low cost and simple control scheme. The operation principle, control scheme, and circuit implementation of the proposed topology are provided. The converter is driven in two-module interleaved topology to operate at a power level of 5.5 kW, whereas phase-shedding control is adopted for light load efficiency improvement. Negative bias circuit is used in gate drivers to avoid the shoot-through induced by high speed switching. The superiority of GaN FET is verified by constructing a 5.5 kW prototype of two-module interleaved totem-pole bridgeless boost PFC converter. The experiment results show the highest efficiency of 98.7% at 1.6 kW load and an efficiency of 97.7% at the rated load.

• Journal of Korean Foot and Ankle Society
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• v.21 no.4
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• pp.156-164
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• 2017

Purpose: Foot and ankle disease (FAD) is a frequent cause of morbidity among the homeless population. Various conditions, exacerbated by malnutrition, poor lifestyle habits, psychiatric disorders, physical injuries, poor hygiene, and limited access to healthcare, have been described in this population. The purpose of this study was to investigate the cognition and management status of FAD in shelter based homeless people. Materials and Methods: Fifty-two male and twenty-five female volunteer homeless individuals were recruited from two homeless shelters. Each person completed a questionnaire assessing any presence of pain, pain management, as well as foot and ankle care status. A foot and ankle surgeon examined the physical status of the individual's foot and ankle, including tenderness and instability. A radiologic evaluation was done for 18 male and 11 female homeless people who agreed to participate in this test for the existence osteophyte or joint space narrowing representing osteoarthritis and some reference angles for hallux valgus, flatfoot and cavus foot. Results: Homeless people had higher prevalence of body mass index, diabetes, and smoking than the general population. The most prevalent infectious disease was fungal infection (male 78%, female 68%), with a low compliance of management for FAD. Conclusion: Although most of shelter-based homeless people showed an acceptable foot and ankle management status, the potential risk for FAD development and exacerbation of mild FAD was high.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.9
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• pp.722-730
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• 2018

This paper presents an analysis technique for estimating the properties of a target's power-spill patterns observed in reconstructed SAR images, which in turn depend on the setup squint angle of the FMCW signal-based SAR system. The target responses observed in the reconstructed SAR images were affected by the range-direction and azimuth-direction of a wave projected on the ground, and the obtained results were analyzed by applying three-dimensional squinted SAR geometry. Furthermore, the rotation patterns were verified through simulations based on the FMCW signal model and back-projection algorithm. This paper summarizes the obtained evaluation results as a function of SAR geometry and squint angle.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.37
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• pp.45.1-45.8
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• 2015

Background: Radial forearm free flap is the most reliable flap for intraoral soft tissue reconstruction after cancer ablation surgery. However, unesthetic scar of the donor site and the need for a second donor site for skin graft are major disadvantages of the forearm flap. The purpose of this study was to report the clinical results of double-layered collagen graft to the donor site of the forearm free flap without skin graft. Methods: Twenty-two consecutive patients who underwent oral cancer ablation and forearm reconstruction between April 2010 and November 2013 were included in this study. Male to female ratio was 12:10, and average age was 61.0 years old (27-84). Double-layered collagen was grafted to the donor site of the forearm free flap and healed for secondary intention. Upper silicone had been trimmed at the periphery during secondary intention, and dry dressing was used. Postoperative scar healing and esthetic results and function were evaluated. Results: An average follow-up period was 34.9 months. The scar area was decreased to 63.9 % in average. The complete healing was obtained between 1.5 and 3 months according to the defect size. There was no functional defect or impairment 3 months after operation. All patients were satisfied with the esthetic results. Three patients died of recurred cancer. Conclusions: Double-layered collagen graft was successfully performed in this study. Without the thigh skin graft, patients had experienced less painful postoperative healing periods and discomfort.

• Journal of Korean Society of Transportation
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• v.32 no.5
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• pp.421-430
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• 2014

The greenhouse gas emission generated by idling vehicles is a critical issue in the greenhouse gas reduction from the transportation sector. Recently, the mandatory application of the Idle Stop and Go (ISG) for buses, trucks and taxis is in the process of legislation. Focusing on the regulation is about to apply to passenger cars, this study analyzed the quantitative economic effects of the ISG installation by passenger car types in Seoul metropolitan area to support proper policy making. The benefit cost ratio of ISG installation on commercial passenger car of Seoul is the most effective, calculated as 8.55. Accordingly, the amount of 660 liters (per year per vehicle) of fuel and 1,606 kg (per year per vehicle) of $CO_2$ could be reduced. The results of this study might be used as an index for judgment of policy such as determining appropriate subsidy for ISG installation on passenger cars.

• Mass Spectrometry Letters
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• v.5 no.1
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• pp.16-23
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• 2014

Liquid chromatography based mass spectrometry (LC-MS) is a key technology for analyzing highly complex and dynamic proteome samples. With highly accurate and sensitive LC-MS analysis of complex proteome samples, efficient data processing is another critical issue to obtain more information from LC-MS data. A typical proteomic data processing starts with protein database search engine which assigns peptide sequences to MS/MS spectra and finds proteins. Although several search engines, such as SEQUEST and MASCOT, have been widely used, there is no unique standard way to interpret MS/MS spectra of peptides. Each search engine has pros and cons depending on types of mass spectrometers and physicochemical properties of peptides. In this study, we describe a novel data process pipeline which identifies more peptides and proteins by correcting precursor ion mass numbers and unifying multi search engines results. The pipeline utilizes two open-source software, iPE-MMR for mass number correction, and iProphet to combine several search results. The integrated pipeline identified 25% more proteins in mouse epididymal adipose tissue compared with the conventional method. Also the pipeline was validated using control and colitis induced colon tissue. The results of the present study shows that the integrated pipeline can efficiently identify increased number of proteins compared to the conventional method which can be a breakthrough in identification of a potential biomarker candidate.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.26 no.1
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• pp.38-44
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• 2015

Objectives : The purpose of this study is to examine the effects of the characteristics of victim and sexual abuse on posttraumatic psychiatric symptoms in children and adolescents with a history of sexual abuse. Methods : A total of 137 children and adolescents were recruited from the Seoul Sunflower Children Center, a nation-funded sexual violence victim protection center, from January 2009 to December 2013. We collected the demographic data of the victims and the Trauma Symptom Checklist for Children (TSCC) from victims. We hypothesized victims' age, sex, and intelligence quotient, and the characteristics of sexual abuse as the affecting factors of posttraumatic psychiatric symptoms. Descriptive analysis and hierarchical regression analysis were performed for analysis of demographic data, TSCC scores, and psychiatric symptoms. Results : The victims' age and the characteristics of sexual abuse were significantly related to the traumatic distress of sexual abuse. R-square was 23% for anxiety, 39% for depression, 21% for posttraumatic stress, and 37% for dissociation on TSCC. Conclusion : This study suggests that victims' age, type, frequency and duration of exposure, and disclosure of sexual abuse are significant affecting factors on posttraumatic psychiatric symptoms in children and adolescents. Exploration of psychiatric symptoms other than posttraumatic symptoms, and relations between pretraumatic and posttraumatic psychiatric symptoms is needed through collection of larger samples.