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Cost-Effective Single Switch Multi-Channel LED Driver

Sang-Soo Hwang, Won-Sun Hwang, Sang-Kyoo Han
2015 Journal of Power Electronics (JPE)  
In this paper, a cost-effective single switch multi-channel LED (light emitting diode) driver is proposed. While conventional LED drivers require as many non-isolated DC/DC converters as the number of LED channels, the proposed LED driver needs only one power switch and several balancing capacitors instead of expensive non-isolated DC/DC converters. Therefore, the proposed driver features a simpler structure, with a lower cost and a higher efficiency. Because its power switch can be turned off
more » ... nder the zero current switching condition, it has very desirable advantages such as improved electromagnetic interference characteristics and high efficiency. Moreover, it uses only a small number of DC blocking capacitors with no additional active devices for the current balancing of multi-channel LEDs. As a result, the proposed driver exhibits high reliability and is cost effective. To confirm the validity of the proposed driver, a theoretical analysis is performed, and design considerations and experimental results obtained from a prototype that is applicable to a 46" LED-TV are presented.
doi:10.6113/jpe.2015.15.2.319 fatcat:3iti4ebddrgehjcvuiejqlpsb4

Won-Seok Hwang) (Soo-Min Chae) (Sang-Wook Kim

Ho, Jin Choi
Researchers use a search engine for finding what they want to read from an article database. Because the search engine normally returns a large number of articles as a search result, they could not find the articles that they want. A ranking method solves this problem by giving proper ranks to articles. In this paper, we define the articles that researchers want to read as high quality articles, and propose a ranking method, ArtRank, to give high ranks to these articles. For determining the
more » ... of an article, ArtRank simultaneously considers the authority of the articles that cite it and the reputation of a journal or a conference where it is published. We point out the problem of the existing impact factor that is employed for determining the reputation of a journal or a conference, and propose its solution. Also, for solving the problem of underestimation of the recent articles, ArtRank analyzes the publication years of articles and applies the result of analysis to the ranking computation process. We show the effectiveness of ArtRank by comparing its search results with those of prior article ranking methods.

Robustifying Multi-hop QA through Pseudo-Evidentiality Training [article]

Kyungjae Lee, Seung-won Hwang, Sang-eun Han, Dohyeon Lee
2021 arXiv   pre-print
This paper studies the bias problem of multi-hop question answering models, of answering correctly without correct reasoning. One way to robustify these models is by supervising to not only answer right, but also with right reasoning chains. An existing direction is to annotate reasoning chains to train models, requiring expensive additional annotations. In contrast, we propose a new approach to learn evidentiality, deciding whether the answer prediction is supported by correct evidences,
more » ... t such annotations. Instead, we compare counterfactual changes in answer confidence with and without evidence sentences, to generate "pseudo-evidentiality" annotations. We validate our proposed model on an original set and challenge set in HotpotQA, showing that our method is accurate and robust in multi-hop reasoning.
arXiv:2107.03242v1 fatcat:qa777xdycrcrpcrdnn5nprptde

Controlling Ferromagnetic Easy Axis in a LayeredMoS2Single Crystal

Sang Wook Han, Young Hun Hwang, Seon-Ho Kim, Won Seok Yun, J. D. Lee, Min Gyu Park, Sunmin Ryu, Ju Sang Park, Dae-Hwang Yoo, Sang-Pil Yoon, Soon Cheol Hong, Kwang S. Kim (+1 others)
2013 Physical Review Letters  
We report the effective methods to induce weak ferromagnetism in pristine MoS 2 persisting up to room temperature with the improved transport property, which would lead to new spintronics devices. The hydrogenation of MoS 2 by heating at 300 C for 1 h leads to the easy axis out of plane, while the irradiation of proton with a dose of 1 Â 10 13 P=cm 2 leads to the easy axis in plane. The theoretical modeling supports such magnetic easy axes.
doi:10.1103/physrevlett.110.247201 pmid:25165955 fatcat:esatbpmhjzbejgygmr27dvpj4m

Colorimetric comparison of single layered dental composite with double layered dental composite

Young-Sang Song, Ja-Hyun Kim, Bin-Na Lee, Ji-Hyun Jang, Hoon-Sang Chang, Yun-Chan Hwang, Won-Mann Oh, In-Nam Hwang
2012 Restorative Dentistry & Endodontics  
Objectives: This study analyzed the difference in color caused by different thickness in enamel layer of composite resins when applied with single and layering placement technique, and evaluated if the results agreed with the shade guide from the manufacturers to verify reliability of the color matching process of the manufacturers. Materials and Methods: For single composite resin samples, 6 mm diameter and 4 mm thickness cylindrical samples were fabricated using Ceram-X mono (DENTSPLY DeTrey)
more » ... and CIE L*a*b* values were measured with spectrophotometer. Same process was done for layering composite resin samples, making 3 dentinal shade samples, 4 mm thickness, for each shade using Ceram-X duo (DENTSPLY DeTrey) and enamel shade resins were layered in 2 mm thickness and CIE L*a*b* values were measured. These samples were ground to 0.2 mm thickness each time, and CIE L*a*b* values were measured to 1 mm thickness of enamel shade resin. Results: Color difference (ΔE*) between single and layering composite resin was 1.37 minimum and 10.53 maximum when layering thicknesses were between 1 mm and 2 mm and 6 out of 10 same shade groups suggested by manufacturer showed remarkable color difference at any thickness (ΔE* > 3.3). Conclusion: When using Ceram-X mono and duo for composite resin restoration, following the manufacturer's instructions for choosing the shade is not appropriate, and more accurate information for Ceram-X duo is needed on the variation and expression of the shades depending on the thickness of the enamel. (Restor Dent Endod 2012;37(2):84-89)
doi:10.5395/rde.2012.37.2.84 fatcat:bk7vt4cqgvdrza5g37q5f52p6i

Triterpenoid Saponins Isolated fromPlatycodon grandiflorumInhibit Hepatitis C Virus Replication

Jong-Woo Kim, Sang Jin Park, Jong Hwan Lim, Jae Won Yang, Jung Cheul Shin, Sang Wook Lee, Joo Won Suh, Soon B. Hwang
2013 Evidence-Based Complementary and Alternative Medicine  
Hepatitis C virus (HCV) infection is a major cause of liver disease, including cirrhosis and hepatocellular carcinoma. Due to significant adverse effects and emergence of resistant strains of currently developed anti-HCV agents, plant extracts have been considered to be potential sources of new bioactive compounds against HCV. The aim of this study was to evaluate the functional effects of triterpenoid saponins contained in the root extract ofPlatycodon grandiflorum(PG) on viral enzyme
more » ... s and replication in both HCV replicon cells and cell culture grown HCV- (HCVcc-) infected cells. Inhibitory activities of triterpenoid saponins from PG were verified by NS5B RNA-dependent RNA polymerase assay and were further confirmed in the context of HCV replication. Six triterpenoid saponins (platycodin D, platycodin D2, platycodin D3, deapioplatycodin D, deapioplatycodin D2, and platyconic acid A), PG saponin mixture (PGSM), were identified as active components exerting anti-HCV activity. Importantly, PGSM exerted synergistic anti-HCV activity in combination with either interferon-αor NS5A inhibitors. We demonstrated that combinatorial treatment of PGSM and IFN-αefficiently suppressed colony formation with significant reduction in drug resistant variant of HCV. These data suggest that triterpenoid saponin may represent a novel anti-HCV therapeutic agent.
doi:10.1155/2013/560417 pmid:24489585 pmcid:PMC3893781 fatcat:zwitxkoa3ng35lixhvgcgjibfe

Rho-kinase mediates the anorexigenic action of melanocortin by suppressing AMPK [article]

Sang Soo Kim, Won Min Hwang, Won Mo Yang, Hyon Lee, Kyong Soo Park, Yossi Dagon, Young-Bum Kim
2019 bioRxiv   pre-print
Objective: Melanocortin action is essential for the maintenance of energy homeostasis. However, knowledge of the signaling mechanism(s) that mediates the effect of melanocortin remains incomplete. Methods: ROCK1 is a key regulator of energy balance in the hypothalamus. To explore the role of ROCK1 in the anorexigenic action of melanocortin, we deleted ROCK1 in MC4R neurons in mice. Next, we studied the metabolic effects of MC4R neuron-specific ROCK1-deficiency and following treatment with
more » ... melanocyte-stimulating hormone (MSH). Results: Here we show that alpha-MSH increases Rho-kinase 1 (ROCK1) activity in the hypothalamus. Deficiency of ROCK1 in MC4R-expressing neurons results in increased body weight in mice fed normal chow diet. This is likely due to increased food intake and decreased energy expenditure. Importantly, we find that ROCK1 activation in MC4R expressing neurons is required for melanocortin action, as evidenced by the fact that alpha-MSH's ability to suppress food intake is impaired in MC4R neuron-specific ROCK1-deficient mice. To elucidate the mechanism by which ROCK1 mediates melanocortin action, we performed in vitro studies in hypothalamic cells expressing MC4R. We demonstrate that alpha-MSH promotes the physical interaction of ROCK1 and Gα12, and this results in suppression of AMPK activity. Conclusions: Our study identifies ROCK1 as a novel mediator of melanocortin's anorexigenic action and uncover a new MC4R→Gα12→ROCK1→AMPK signaling pathway. Targeting Rho-kinase in MC4R-expressing neurons could provide a new strategy to combat obesity and its related complications.
doi:10.1101/677880 fatcat:wzqs3k7dmvcdfkgp5cxvp4zb24

Plug-and-Play Adaptation for Continuously-updated QA [article]

Kyungjae Lee, Wookje Han, Seung-won Hwang, Hwaran Lee, Joonsuk Park, Sang-Woo Lee
2022 arXiv   pre-print
Language models (LMs) have shown great potential as implicit knowledge bases (KBs). And for their practical use, knowledge in LMs need to be updated periodically. However, existing tasks to assess LMs' efficacy as KBs do not adequately consider multiple large-scale updates. To this end, we first propose a novel task--Continuously-updated QA (CuQA)--in which multiple large-scale updates are made to LMs, and the performance is measured with respect to the success in adding and updating knowledge
more » ... hile retaining existing knowledge. We then present LMs with plug-in modules that effectively handle the updates. Experiments conducted on zsRE QA and NQ datasets show that our method outperforms existing approaches. We find that our method is 4x more effective in terms of updates/forgets ratio, compared to a fine-tuning baseline.
arXiv:2204.12785v1 fatcat:nwtlojtexvfqbeejfdfmn3gioy

A review of the regenerative endodontic treatment procedure

Bin-Na Lee, Jong-Wook Moon, Hoon-Sang Chang, In-Nam Hwang, Won-Mann Oh, Yun-Chan Hwang
2015 Restorative Dentistry & Endodontics  
Traditionally, apexification has been used to treat immature permanent teeth that have lost pulp vitality. This technique promotes the formation of an apical barrier to close the open apex so that the filling materials can be confined to the root canal. Because tissue regeneration cannot be achieved with apexification, a new technique called regenerative endodontic treatment was presented recently to treat immature permanent teeth. Regenerative endodontic treatment is a treatment procedure
more » ... ned to replace damaged pulp tissue with viable tissue which restores the normal function of the pulp-dentin structure. After regenerative endodontic treatment, continued root development and hard tissue deposition on the dentinal wall can occur under ideal circumstances. However, it is difficult to predict the result of regenerative endodontic treatment. Therefore, the purpose of this study was to summarize multiple factors effects on the result of regenerative endodontic treatment in order to achieve more predictable results. In this study, we investigated the features of regenerative endodontic treatment in comparison with those of other pulp treatment procedures and analyzed the factors that have an effect on regenerative endodontic treatment.
doi:10.5395/rde.2015.40.3.179 pmid:26295020 pmcid:PMC4534721 fatcat:4bxte4koqvecbn4roefk3ii5ka

Ferroelectric Copolymer-Based Plastic Memory Transistors [chapter]

Sung-Min Yoon, Shinhyuk Yang, Soon-Won Jung, Sang-Hee Ko, Chun-Won Byun, Min-Ki Ryu, Himchan Oh, Chi-Sun Hwang, Kyoung-Ik Cho, Byoung-Gon Yu
2011 Ferroelectrics - Applications  
doi:10.5772/17547 fatcat:eqi66ljjibgp7mhp5gf3k75uba

A Case of Sparganosis That Presented as a Recurrent Pericardial Effusion

Ju-Hee Lee, Gi-Hyun Kim, Sang Min Kim, Sang Yeub Lee, Won-Yik Lee, Jang-Whan Bae, Kyung-Sub Shin, Kyung-Kuk Hwang, Dong-Won Kim, Myeong-Chan Cho
2011 Korean Circulation Journal  
Sparganosis is caused by a larval tapeworm of the genus Spirometra, which commonly invades subcutaneous tissue, but less frequently invades muscle, intestines, spinal cord, and the peritoneopleural cavity. The authors managed a female patient who presented with a recurrent pericardiopleural effusion and peripheral eosinophilia. The anti-sparganum-specific IgG serum level was significantly higher than normal control levels. In this patient, sparganosis was caused by the ingestion of raw frogs in
more » ... an effort to control her thyroid disease. The recurrent pericardiopleural effusion and peripheral eosinophilia were controlled by 3 consecutive doses of praziquantel (75 mg/kg/day). The patient is doing well 4 years after presentation. Sparganosis should be considered a rare, but possible cause of recurrent pericardial effusion and peripheral eosinophilia. Immunoserologic testing using enzyme linked immunosorbent assays can be helpful in diagnosing human sparganosis, especially in cases without a subcutaneous lump or mass. Praziquantel is an alternative treatment for sparganosis in surgically-unresectable cases. (Korean Circ J 2011;41:38-42)
doi:10.4070/kcj.2011.41.1.38 pmid:21359068 pmcid:PMC3040402 fatcat:n2i4ih353vft3daroqd22do2gu

Duodenal amyloidosis secondary to ulcerative colitis

Seung Woon Park, Sam Ryong Jee, Ji Hyun Kim, Sang Heon Lee, Jin Won Hwang, Ji Geon Jang, Dong Woo Lee, Sang Yong Seol
2018 Intestinal Research  
A 36-year-old male patient with a 15-year history of UC presented with nausea, vomiting, and abdominal pain. When he was first diagnosed with UC 15 years ago, colonoscopy showed multiple ulcers, mucosal friability, and bleeding throughout the entire colon and rectum. The Mayo score was 9. After being diagnosed with UC, he was treated with mesalazine and intermittent steroid therapy for 9 years, until cyclosporine therapy was administered due to development of steroid-refractory UC 3 years
more » ... As cyclosporine was not effective, he was then treated with infliximab for 6 years. Currently, he is being treated with mesalazine and adalimumab since 5 months. Clinical tests revealed mucosal friability and multiple erosions without ulcers and bleeding throughout the entire colon, while the Mayo score was 4. Upon physical examination, a normoactive bowel sound was heard, the abdomen was found to be flat, and tender-Amyloidosis is defined as the extracellular deposition of non-branching fibrils composed of a variety of serum-protein precursors. Secondary amyloidosis is associated with several chronic inflammatory conditions, such as rheumatologic or intestinal diseases, familial Mediterranean fever, or chronic infectious diseases, such as tuberculosis. Although the association of amyloidosis with inflammatory bowel disease is known, amyloidosis secondary to ulcerative colitis (UC) is rare. A 36-year-old male patient with a 15-year history of UC presented with nausea, vomiting, and abdominal pain. He had been treated with infliximab for 6 years. At the time of admission, he had been undergoing treatment with mesalazine and adalimumab since the preceding 5 months. Esophagogastroduodenoscopy showed mucosal erythema, edema, and erosions with geographic ulcers at the 2nd and 3rd portions of the duodenum. Duodenal amyloidosis was diagnosed using polarized light microscopy and Congo red stain. Monoclonal gammopathy was not detected in serum and urine tests, while the serum free light chain assay result was not specific. An increase in plasma cells in the bone marrow was not found. Secondary amyloidosis due to UC was suspected. The symptoms were resolved after glucocorticoid therapy. (Intest Res 2018;16:151-154)
doi:10.5217/ir.2018.16.1.151 pmid:29422811 pmcid:PMC5797263 fatcat:dfuynjbdqjghlggqohqhuwh2ci

Treatment of horizontal root-fractured maxillary incisors

Sung-Hyeon Choi, Ji-Hye Yoon, Bin-Na Lee, Hoon-Sang Chang, In-Nam Hwang, Won-Mann Oh, Yun-Chan Hwang
2019 Oral Biology Research  
Root fractures are defined as fractures that involve the dentin, cementum, and pulp, resulting in stretching or laceration of the pulp and/or periodontal ligament injury (rupture or compression). Two cases of horizontal root-fractured maxillary incisors are introduced in the present report. The first case is a middle third root-fractured maxillary incisor with root canal therapy in the coronal fragment, and the second case is a cervical third root-fractured maxillary incisor without root canal
more » ... herapy. Both cases showed favorable results with a long-term follow-up period. In all traumatic injuries, early diagnosis and appropriate intervention dramatically enhance the outcome. The primary purpose of the treatment of root-fractured teeth is to maintain the vitality of the teeth. After an adequate observation period, if vitality control reveals non-vital pulp tissue, or if the patient complains of pain or discomfort in the tooth, endodontic therapy can be performed, usually to the coronal segment only.
doi:10.21851/obr.43.03.201909.236 fatcat:pyuujxps3bf2pk2udfs33g2h6e

Developed hyponatremia during hysteroscopic myomectomy - A case report -

Hwan-Hee Kim, Jin-Young Hwang, Young-Tae Jeon, Jung-Won Hwang, Sang-Hwan Do, Hyo-Seok Na
2009 Korean Journal of Anesthesiology  
Hysteroscopy is frequently used to assist the diagnosis and treatment of a series uterine diseases. However, complications associated with the procedure including fluid overload, hyponatremia, hypo-osmolality, hemorrhage, uterine perforation, and air embolism have been reported. The incidence of fluid overload with hyponatremia during hysteroscopic procedures has been reported to be up to 6% and it can probe fatal. Thus, early recognition of this condition and prompt intervention thereof is
more » ... rtant to prevent adverse sequelae. Here, we report a case of hyponatremia with incidental fluid overload during hysteroscopy. We detected the signs of complication early on and were thus able to manage it promptly without any resulting adverse sequelae. (Korean J Anesthesiol 2009; 57: 629∼32)
doi:10.4097/kjae.2009.57.5.629 fatcat:zwjut2764vbndd7mzfzxiuxalq

Translational radionanomedicine: a clinical perspective

Hongyoon Choi, Yun-Sang Lee, Do Won Hwang, Dong Soo Lee
2016 European Journal of Nanomedicine  
AbstractMany nanomaterials were developed for the anticipated in vivo theranostic use exploiting their unique characteristics as a multifunctional platform. Nevertheless, only a few nanomaterials are under investigation for human use, most of which have not entered clinical trials yet. Radionanomedicine, a convergent discipline of radiotracer technology and use of nanomaterials in vivo, can facilitate clinical nanomedicine because of its advantages of radionuclide imaging and internal radiation
more » ... therapy. In this review, we focuse on how radionanomedicine would impact profoundly on clinical translation of nanomaterial theranostics. Up-to-date advances and future challenges are critically reviewed regarding the issues of how to radiolabel and engineer radionanomaterials, in vivo behavior tracing of radionanomaterials and then the desired clinical radiation dosimetry. Radiolabeled extracellular vesicles were further discussed as endogenous nanomaterials radiolabeled for possible clinical use.
doi:10.1515/ejnm-2015-0052 fatcat:7eal42xd6fbapix2ofxnznyllu
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