Artificial Neural Network for Modeling the Tensile Properties of Ferrite-Pearlite Steels: Relative Importance of Alloying Elements and Microstructural Factors

Tae‑Woon Hong,Sang‑In Lee,Jae‑Hyeok Shim,Myoung‑Gyu Lee,Joonho Lee,Byoungchul Hwang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

An artificial neural network (ANN) model was developed to predict the tensile properties as a function of alloying elementand microstructural factor of ferrite-pearlite steels. The input parameters of the model were composed of alloying elements(Mn, Si, Al, Nb, Ti, and V) and microstructural factors (pearlite fraction, ferrite grain size, interlamellar spacing, and cementitethickness), while the output parameters of the model were yield strength and tensile strength. Although the ferrite-pearlitesteels have complex relationships among the alloying elements, microstructural factors, and tensile properties, the ANNmodel predictions were found to be more accurate with experimental results than the existing equation model. In the presentstudy the individual effect of input parameters on the tensile properties was quantitatively estimated with the help of theaverage index of the relative importance for alloying elements as well as microstructural factors. The ANN model attemptedfrom the metallurgical points of view is expected to be useful for designing new steels having required mechanical properties.

Korean English Teacher's Disempowerment in English-only Classes

Sung-Sam Hwang,Hyo-Sun Seo,Tae-Young Kim 한국사회언어학회 2010 사회언어학 Vol.18 No.1

Hwang, Sung-Sam, SeD, Hyo-Sun, Kim, Tae-Young. 2010. Korean English Teacher's Disempowerment in English-only Classes: A Case Study Focusing on Korea-specific Cultural Aspects. The Sociolinguistic journal of Korea 18(1). In this case study, we have focused on the disempowerment of a Korean English teacher (KET) in English-only classrooms. Six English as a foreign language (EFL) classrooms in a Korean high school were observed and analyzed by using interpretive discourse analysis. Out of the six classes, three representative classrooms were both video- and audio-taped. The results show that the English-only classes could weaken the KETs' power via three mechanisms: (a) calling the KETs' last name for choral greetings at the beginning of the class, (b) students' group solidarity and peer pressure between classmates, and (c) the students' excessively collaborative approach to peer assistance. It is argued that the exclusive English-only instruction disempowers the KETs' status and dismantles their vocational identity. In order to remedy the current situation, within a scaffolding supported by the eclectic use of first language where necessary for effective class management, KETs are empowered and overcome constraints imposed by the limited L2 oral competence of some non-native English teachers.

삼나무 (杉) 내한성 (耐寒性) 품종 선발에 관한 연구

홍성각,조태환,황증 ( Sung Gak Hong,Tae Hwan Cho,Jeung Hwang ) 한국산림과학회 1981 한국산림과학회지 Vol.51 No.1

This study was designed to know difference in degree of dehardening and rehardening respectively by artificial high and low temperature treatments among different clonal seedlings and seedlings from different seed sources of Cryptomeria japonica which have been grown under the cold areas in Japan and Korea. High temperature treatment was done with 15 to 20℃ under 100% relative humidity for one to nine days and low temperature treatment was carried with -7℃ for one to three days. Occasionaly, high temperature treatment was combined and followed by low temperature treatment. The ability of stem section to delay dehardening by high temperature treatment and/or to hasten rehardening by low temperature treatment was used as an indicator of adaptability under extreme temperature fluctuation in nature. Clones and seedlings from different seed sources which showed greater freezing resistance than others after artificial high and/or low temperature treatments were selected over two to three time periods: early winter, mid winter and early spring in 1977 to 1980. These were Seoul #7, and #9, Namboo #3, and #4, Sung-Kang #11, Chung-Sam #8 and Huek-Suk #9. These selected seedlings might have survival advantage to withstand early and late frost damage, especially the critical frost damage of the basal stem, since it was known to be induced by lowering freezing resistance of the basal part when exposed to the high temperature near the ground during the day. Large variation in freezing resistance and degree of dehardening and rehardening was found among clonal or seed sources and among individuals within a seed source, but was not related to the difference in climatic conditions where the parent trees was selected. These indicated the possibility of future breeding work for more cold resistant family of Cryptomeria japonica.

Tamoxifen therapy improves overall survival in luminal A subtype of ductal carcinoma in situ: a study based on nationwide Korean Breast Cancer Registry database

Hwang, Ki-Tae,Kim, Eun-Kyu,Jung, Sung Hoo,Lee, Eun Sook,Kim, Seung Il,Lee, Seokwon,Park, Heung Kyu,Kim, Jongjin,Oh, Sohee,Kim, Young A. Springer-Verlag 2018 Breast cancer research and treatment Vol.169 No.2

Web-based design and analysis tools for CRISPR base editing

Hwang, Gue-Ho,Park, Jeongbin,Lim, Kayeong,Kim, Sunghyun,Yu, Jihyeon,Yu, Eunchong,Kim, Sang-Tae,Eils, Roland,Kim, Jin-Soo,Bae, Sangsu BioMed Central 2018 BMC bioinformatics Vol.19 No.1

<P><B>Background</B></P><P>As a result of its simplicity and high efficiency, the CRISPR-Cas system has been widely used as a genome editing tool. Recently, CRISPR base editors, which consist of deactivated Cas9 (dCas9) or Cas9 nickase (nCas9) linked with a cytidine or a guanine deaminase, have been developed. Base editing tools will be very useful for gene correction because they can produce highly specific DNA substitutions without the introduction of any donor DNA, but dedicated web-based tools to facilitate the use of such tools have not yet been developed.</P><P><B>Results</B></P><P>We present two web tools for base editors, named BE-Designer and BE-Analyzer. BE-Designer provides all possible base editor target sequences in a given input DNA sequence with useful information including potential off-target sites. BE-Analyzer, a tool for assessing base editing outcomes from next generation sequencing (NGS) data, provides information about mutations in a table and interactive graphs. Furthermore, because the tool runs client-side, large amounts of targeted deep sequencing data (< 1 GB) do not need to be uploaded to a server, substantially reducing running time and increasing data security. BE-Designer and BE-Analyzer can be freely accessed at http://www.rgenome.net/be-designer/ and http://www.rgenome.net/be-analyzer/, respectively.</P><P><B>Conclusion</B></P><P>We develop two useful web tools to design target sequence (BE-Designer) and to analyze NGS data from experimental results (BE-Analyzer) for CRISPR base editors.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s12859-018-2585-4) contains supplementary material, which is available to authorized users.</P>

Determination of Malignant and Invasive Predictors in Branch Duct Type Intraductal Papillary Mucinous Neoplasms of the Pancreas: A Suggested Scoring Formula

Hwang, Dae Wook,Jang, Jin-Young,Lim, Chang-Sup,Lee, Seung Eun,Yoon, Yoo-Seok,Ahn, Young Joon,Han, Ho-Seong,Kim, Sun-Whe,Kim, Sang Geol,Yun, Young Kook,Han, Seong-Sik,Park, Sang-Jae,Lim, Tae Jin,Kang, The Korean Academy of Medical Sciences 2011 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.26 No.6

<P>Prediction of malignancy or invasiveness of branch duct type intraductal papillary mucinous neoplasm (Br-IPMN) is difficult, and proper treatment strategy has not been well established. The authors investigated the characteristics of Br-IPMN and explored its malignancy or invasiveness predicting factors to suggest a scoring formula for predicting pathologic results. From 1994 to 2008, 237 patients who were diagnosed as Br-IPMN at 11 tertiary referral centers in Korea were retrospectively reviewed. The patients' mean age was 63.1 ± 9.2 yr. One hundred ninty-eight (83.5%) patients had nonmalignant IPMN (81 adenoma, 117 borderline atypia), and 39 (16.5%) had malignant IPMN (13 carcinoma in situ, 26 invasive carcinoma). Cyst size and mural nodule were malignancy determining factors by multivariate analysis. Elevated CEA, cyst size and mural nodule were factors determining invasiveness by multivariate analysis. Using the regression coefficient for significant predictors on multivariate analysis, we constructed a malignancy-predicting scoring formula: 22.4 (mural nodule [0 or 1]) + 0.5 (cyst size [mm]). In invasive IPMN, the formula was expressed as invasiveness-predicting score = 36.6 (mural nodule [0 or 1]) + 32.2 (elevated serum CEA [0 or 1]) + 0.6 (cyst size [mm]). Here we present a scoring formula for prediction of malignancy or invasiveness of Br-IPMN which can be used to determine a proper treatment strategy.</P>

Influence of silicon content on microstructure and mechanical properties of Ti-Cr-Si alloys

Hwang, Yun Jung,Hong, Sung Hwan,Kim, Young Seok,Park, Hae Jin,Jeong, Yeon Beom,Kim, Jeong Tae,Kim, Ki Buem Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.737 No.-

<P><B>Abstract</B></P> <P>The microstructural evolutions related to mechanical properties were investigated for Ti-Cr-Si alloys. The volume fraction of constituting phases in these alloys was changed by the additional Si elements. The alloy containing 2 at.% of Si consisted of a fully β-Ti phase and exhibited reasonable yield strength (∼960 MPa) without fracture under compression. The Ti<SUB>78</SUB>Cr<SUB>16</SUB>Si<SUB>6</SUB> alloy containing the β-Ti dendrite with a small amount of nano-scale layer-structured matrix exhibited an enhanced yield strength (1384 MPa) and a large plastic strain of ∼30%. With increasing Si contents up to 10 at.%, the volume fraction of the matrix increased more than half, which led to a tradeoff between the strength (1580 MPa) and the plasticity (7.8%). These results reveal that introducing a nano-scale layer-structured matrix in the β-Ti alloys is very effective to enhance the yield strength. Moreover, the optimized mechanical properties can be achieved by a modulation of the volume ratio between β-Ti dendrite and the matrix in Ti-Cr-Si alloys.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An addition of Si induces the introducing nanoscale layer-structured matrix. </LI> <LI> Formation of the matrix in Ti-Cr-Si is effective to enhance the yield strength. </LI> <LI> Optimized mechanical properties are achieved from suitable volume ratio of dendrite/matrix. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of a Facial Muscle Exercise Device on Facial Rejuvenation

Hwang, Ui-jae,Kwon, Oh-yun,Jung, Sung-hoon,Ahn, Sun-hee,Gwak, Gyeong-tae Oxford University Press 2018 Aesthetic surgery journal Vol.38 No.5

<P><B>Abstract</B></P><P><B>Background</B></P><P>The efficacy of facial muscle exercises (FMEs) for facial rejuvenation is controversial. In the majority of previous studies, nonquantitative assessment tools were used to assess the benefits of FMEs.</P><P><B>Objectives</B></P><P>This study examined the effectiveness of FMEs using a Pao (MTG, Nagoya, Japan) device to quantify facial rejuvenation.</P><P><B>Methods</B></P><P>Fifty females were asked to perform FMEs using a Pao device for 30 seconds twice a day for 8 weeks. Facial muscle thickness and cross-sectional area were measured sonographically. Facial surface distance, surface area, and volumes were determined using a laser scanning system before and after FME. Facial muscle thickness, cross-sectional area, midfacial surface distances, jawline surface distance, and lower facial surface area and volume were compared bilaterally before and after FME using a paired Student <I>t</I> test.</P><P><B>Results</B></P><P>The cross-sectional areas of the zygomaticus major and digastric muscles increased significantly (right: <I>P</I> < 0.001, left: <I>P</I> = 0.015), while the midfacial surface distances in the middle (right: <I>P</I> = 0.005, left: <I>P</I> = 0.047) and lower (right: <I>P</I> = 0.028, left: <I>P</I> = 0.019) planes as well as the jawline surface distances (right: <I>P</I> = 0.004, left: <I>P</I> = 0.003) decreased significantly after FME using the Pao device. The lower facial surface areas (right: <I>P</I> = 0.005, left: <I>P</I> = 0.006) and volumes (right: <I>P</I> = 0.001, left: <I>P</I> = 0.002) were also significantly reduced after FME using the Pao device.</P><P><B>Conclusions</B></P><P>FME using the Pao device can increase facial muscle thickness and cross-sectional area, thus contributing to facial rejuvenation.</P><P><B>Level of Evidence: 4</B></P><P>[GRAPHIC OMISSION]</P>

Metal-induced crystallization of amorphous zinc tin oxide semiconductors for high mobility thin-film transistors

Hwang, Ah Young,Kim, Sang Tae,Ji, Hyuk,Shin, Yeonwoo,Jeong, Jae Kyeong American Institute of Physics 2016 Applied Physics Letters Vol.108 No.15

Shear Strength Degradation Model for Performance-Based Design of Interior Beam-Column Joints

Hwang, Hyeon-Jong,Eom, Tae-Sung,Park, Hong-Gun American Concrete Institute 2017 ACI structural journal Vol.114 No.5

<P>Under cyclic loading, the shear strength of reinforced concrete (RC) beam-column joints is decreased by diagonal cracking and beam bar-slip, as the inelastic deformation increases. In the present study, a joint shear strength model was developed for the performance-based design of interior beam-column joints. As the primary design parameter, the bar bond parameters were used to define the joint shear deformation and shear strength. All possible failure mechanisms of beams and joints were considered: flexural yielding of the beam end (bar fracture or concrete crushing), diagonal cracking and concrete crushing in the joint panel, bar bond-slip, and bar elongation. For verification, the proposed model was applied to 50 existing beam-column joint specimens. The prediction results of joint shear capacity and deformation capacity were compared with the existing test results. The results showed that the predictions generally agreed with the test results.</P>