The Effects of Microeconomic Fundamentals on the Korean Financial Crisis

Kim,Sunghwan,Kim,Hong Kee,Kim,Jin San 한국산업경영학회 2010 한국산업경영학회 발표논문집 Vol.2010 No.1

In this study, we assess the effects of default risks and financial performance of firms on the overall risk of Korea around its financial crisis in the late 1990s and on their market values, using firm-level data from 1991 to 2007. We develop default prediction models and calculate Altman’s K scores to measure the overall risks and quality of firms respectively. Based on our own default prediction models, we have shown that the default risks of firms were extremely high before the crisis and drastically declined after the crisis. We have also found that the default risks of chaebol firms were much lower before and after the financial crisis and that their market values were much higher after the crisis, compared with those of non-chaebol firms. This implies that the Korean economy with high sovereign risks for a long time experienced the crisis due to weak firm-level fundamentals, regained its vitality due to significant improvements made by chaebol firms through the crisis and has become much stronger than before.

The Signaling Effects of Lenders' Reputation On Firm Values

Kim,Sunghwan 한국산업경영학회 2010 한국산업경영학회 발표논문집 Vol.2010 No.2

In this paper, we study the rational behaviors of firms in responses to the market strategy of financial institutions for higher profits in the steady state-economy. We develop theoretical models about the effects of reputation of the financial institutions as principals on their own payoffs and the behaviors of agents or firms in a market with various types of firms with different credit history, based on the reputation theory model of Alexeev and Kim (2004), and four types of rationally behaving firms which are to maximize their chance of credit-financing at a cheaper cost over periods, experiencing the decision of financial institutions as a signal about their type to the market. We have found that a financial institution is more likely to provide funds at a higher interest rate in the monopolistic market than in the competitive market, where two financial institutions play opposite strategies in the competitive market and that in the competitive market, a financial institution is more likely to provide funds at a higher interest rate as the competition in the market intensifies. We also could infer that firms financing more from a hard budgeting financial institution at a relatively low cost will have higher stock prices and thus higher firm values, that firms financing more from a softly budgeting financial institution at a relatively higher cost will have lower stock prices and thus lower firm values, and that firms that did not successfully financed from a hard budgeting financial institution might have higher or lower firm values.

벤처시장에서의 정보의 비대칭과 평판효과가 벤처금융의 성과에 미치는 영향

김성환 ( Sunghwan Kim ) 한국금융공학회 2017 금융공학연구 Vol.16 No.3

본 연구는 정보의 비대칭 문제가 존재하는 벤처금융시장에서 대출 벤처금융의 장기적 성과극대화 기준으로 독점 및 경쟁 시장에서 벤처금융의 부실 벤처기업에 대한 처리과정에서 발생하는 평판효과에 관한 이론모형을 개발하였다. Alexeev and Kim (2004) 모형을 토대로 개발된 Kim (2013) 모형을 확장, 수정하여 다양한 형태의 벤처기업에 대한 차별적 위험프리미엄을 반영하였다. 또한, 이와 관련한 주요 벤처금융 시장의 변수들을 중심으로 균형상태에 미치는 영향을 비교정태 분석하였다. 기본적으로 벤처금융시장에서 위험프리미엄의 존재로 인하여 부실 벤처기업에 대한 비도덕적 또는 단기 지향적 대출가능성이 Kim (2013)보다 더 가능성이 크다고 볼 수 있다. 또한, 부가되는 위험프리미엄으로 인하여 전체적인 부도위험이 커지고 시장 전체의 부실이 더욱 악화되는 것으로 나타났다. 벤처금융시장에서 위험프리미엄 차이가 벤처기업에 대한 지원금융의 효율성과 시장세분화를 통하여 벤처기업에 대한 금융시장의 효율성을 제고할 수 있다. 다만, 전체적 시장 관점에서 벤처기업에 대한 신용정보를 공유하고 벤처기업에 대한 도덕적 해이와 비대칭적 정보에 대하여 공동대응하고, 같은 수준의 위험프리미엄을 부과함으로써 도덕적 해이를 완화할 수 있다. 또한, 전반적인 벤처기업의 금융비용을 줄이게 됨으로써, 시장효율성을 더욱 제고할 수 있다. In this paper, we study the rational behaviors of venture firms in response to the market strategies by extending the reputation model developed by Alexeev and Kim (2004) and Kim (2013) on the basic valuation models of venture firms based on corporate financial performances. In the setup, the performances of lending institutions depend on the performances of borrowing venture firms. We introduce different levels of risk premium, revenue and cost structure, etc. in addition to prior studies with four types of rational venture firm behavior in their steady-state that try to maximize the chances of credit-financing at a cheaper cost and studying the decision of venture capitals as an indicator of their market type to seek high-quality venture firms at lower risk premium and low-quality venture firms at higher risk premium. We find that a venture capital is more likely to provide funds at a higher interest rate, including risk premium in a no-competition capital market, than in the competing capital market for venture firms. In the latter, more than two venture capitals competitively play opposite strategies to win more venture firms. Furthermore, in the competitive market, a venture capital is more likely to provide funds at a higher interest rate, including risk premium as the competition in the market intensifies and information sharing among players can play a critical role.

A Study of CsI(Tl) Scintillator with Optimized Conditions of Large Area Avalanche Photodiode

Kim, Minjeong,Kang, Heedong,Kim, H.J.,Kim, Wan,Park, H.,Kim, Sunghwan Informa UK (Taylor Francis) 2008 Journal of nuclear science and technology Vol.45 No.suppl5

Effect of Previous Gastrectomy on the Performance of Postoperative Colonoscopy

Kim, Sunghwan,Choi, Jeongmin,Kim, Tae Han,Kong, Seong-Ho,Suh, Yun-Suhk,Im, Jong Pil,Lee, Hyuk-Joon,Kim, Sang Gyun,Jeong, Seung-Yong,Kim, Joo Sung,Yang, Han-Kwang The Korean Gastric Cancer Association 2016 Journal of gastric cancer Vol.16 No.3

Purpose: The purpose of this study was to determine the effect of a prior gastrectomy on the difficulty of subsequent colonoscopy, and to identify the surgical factors related to difficult colonoscopies. Materials and Methods: Patients with a prior gastrectomy who had undergone a colonoscopy between 2011 and 2014 (n=482) were matched (1:6) to patients with no history of gastrectomy (n=2,892). Cecal insertion time, intubation failure, and bowel clearance score were compared between the gastrectomy and control groups, as was a newly generated comprehensive parameter for a difficult/incomplete colonoscopy (cecal intubation failure, cecal insertion time >12.9 minutes, or very poor bowel preparation scale). Surgical factors including surgical approach, extent of gastrectomy, extent of lymph node dissection, and reconstruction type, were analyzed to identify risk factors for colonoscopy performance. Results: A history of gastrectomy was associated with prolonged cecal insertion time ($8.7{\pm}6.4$ vs. $9.7{\pm}6.5$ minutes; P=0.002), an increased intubation failure rate (0.1% vs. 1.9%; P<0.001), and a poor bowel preparation rate (24.7 vs. 29.0; P=0.047). Age and total gastrectomy (vs. partial gastrectomy) were found to be independent risk factors for increased insertion time, which slowly increased throughout the postoperative duration (0.35 min/yr). Total gastrectomy was the only independent risk factor for the comprehensive parameter of difficult/incomplete colonoscopy. Conclusions: History of gastrectomy is related to difficult/incomplete colonoscopy performance, especially in cases of total gastrectomy. In any case, it may be that a pre-operative colonoscopy is desirable in selected patients scheduled for gastrectomy; however, it should be performed by an expert endoscopist each time.

Predictors of Permanent Stoma in Mid or Low Rectal Cancer Patients

Sunghwan Kim,Kwang Seop Song,Min-hyun Kim,Sung-Chan Park,Dae Kyung Sohn,Jae Hwan Oh,Ji Won Park,Seung-Yong Jeong,Kyu Joo Park,Heung-Kwon Oh,Duck-Woo Kim,Sung-Bum Kang 대한외과학회 2018 대한외과학회 학술대회 초록집 Vol.2018 No.11

Development of Efficient Brain Age Estimation Method Based on Regional Brain Volume From Structural Magnetic Resonance Imaging

Sunghwan Kim,Sheng-Min Wang,Dong Woo Kang,Yoo Hyun Um,Hyeonsik Yang,Hyunji Lee,Regina EY Kim,Donghyeon Kim,Chang Uk Lee,Hyun Kook Lim 대한신경정신의학회 2024 PSYCHIATRY INVESTIGATION Vol.21 No.1

Objective We aimed to create an efficient and valid predicting model which can estimate individuals’ brain age by quantifying their regional brain volumes.Methods A total of 2,560 structural brain magnetic resonance imaging (MRI) scans, along with demographic and clinical data, were obtained. Pretrained deep-learning models were employed to automatically segment the MRI data, which enabled fast calculation of regional brain volumes. Brain age gaps for each subject were estimated using volumetric values from predefined 12 regions of interest (ROIs): bilateral frontal, parietal, occipital, and temporal lobes, as well as bilateral hippocampus and lateral ventricles. A larger weight was given to the ROIs having a larger mean volumetric difference between the cognitively unimpaired (CU) and cognitively impaired group including mild cognitive impairment (MCI), and dementia groups. The brain age was predicted by adding or subtracting the brain age gap to the chronological age according to the presence or absence of the atrophy region.Results The study showed significant differences in brain age gaps among CU, MCI, and dementia groups. Furthermore, the brain age gaps exhibited significant correlations with education level and measures of cognitive function, including the clinical dementia rating sum-of-boxes and the Korean version of the Mini-Mental State Examination.Conclusion The brain age that we developed enabled fast and efficient brain age calculations, and it also reflected individual’s cognitive function and cognitive reserve. Thus, our study suggested that the brain age might be an important marker of brain health that can be used effectively in real clinical settings.

Crystal Growth and Scintillation Properties of <tex> ${\hbox {Cs}}_{2}{\hbox {NaCeBr}}_{6}$</tex>

Sunghwan Kim,Gul Rooh,Kim, H J,Wan Kim,Hong, U IEEE 2010 IEEE transactions on nuclear science Vol.57 No.3

<P>In this paper crystal growth, luminescence and scintillation properties of Cs<SUB>2</SUB>NaCeBr<SUB>6</SUB> crystal are presented. The studied Cs<SUB>2</SUB>NaCeBr<SUB>6</SUB> crystal was grown by the Bridgman method using a two-zone vertical transparent furnace. The material was synthesized using the reaction 2CsBr + NaBr + CeBr<SUB>3</SUB> → Cs<SUB>2</SUB>NaCeBr<SUB>6</SUB>. Under UV excitation the emission of crystal was observed in the range of 300 to 450 nm with two peaks at 377 and 400 nm. The emission is due to the 5d → 4f transitions on Ce<SUP>3+</SUP>. The energy resolution of the crystal measured under 662 keV was 6.7%. The scintillation decay time showed two components characterized by 140 ns and 880 ns time constants. The light yield of the crystal was estimated to be 25,000 photons/MeV.</P>

Two Years Data of Tenofovir Alafenamide versus Tenofovir Disoproxil Fumarate for the Treatment of Patients with Chronic Hepatitis B

( Sunghwan Yoo ),( Hyun Woong Lee ),( Seung Up Kim ),( Sora Kim ),( Hye Young Chang ),( Jung Il Lee ),( Beom Kyung Kim ),( Jun Yong Park ),( Do Young Kim ),( Kwang-hyub Han ),( Kwan Sik Lee ),( Sang H 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1

Aims: In 96-week results from double-blind, randomized phase III trials, Tenofovir Alafenamide (TAF) continues to be as effective as Tenofovir Disoproxil Fumarate (TDF) with continued improved renal and bone safety. We compared the efficacy and safety of the two drugs in patients with chronic hepatitis B (CHB) for 2 years. Methods: A total of 890 patients with CHB treated with tenofovir alafenamide (TAF, n = 77) or tenofovir disoproxil fumarate (TDF, n = 813) in two tertiary referral centers between November 1, 2017, and December 31, 2017, were analyzed. Eligible patients were aged at least 18 years with chronic HBV infection (with serum HBV DNA concentrations of >2, 000 IU/mL), serum alanine aminotransferase concentrations of greater than 40 U/L and at no more than twenty times the upper limit of normal, and estimated glomerular filtrate rate (eGFR) of at least 50 mL/min (by the Chronic kidney disease epidemiology collaboration). To reduce selection bias and the effect of potential confounders, propensity scores were calculated by logistic regression based on age, gender, diabetes, compensated cirrhosis, and hepatitis B e antigen (HBeAg) status, initial ALT, initial HBV DNA, total bilirubin, albumin, and platelet counts. Differences between the two groups were balanced by a 1:1 PS-matched analysis (TAF, n=77 vs. TDF, n=77). The primary efficacy endpoint was the proportion of patients who had HBV DNA less than 20 IU/mL at week 96; Serum phosphorus, eGFR, and lipid profile were assessed to evaluate the safety. Results: Baseline characteristics were not different between the two groups. Biochemical response (ALT<40 IU/L) rate in TAF and TDF group was 77.9% (60/77) vs 79.2% (61/77) at 1 year, 92.2% (71/77) vs. 89.6% (69/77) at 2 years. Virological response rates (HBV DNA <20IU/mL) was 62.3% (48/77) vs. 66.2% (51/77) at 1 year, 85.7% (66/77) vs. 84.4% (65/77) at 2 years. There were no statistical differences in biochemical and virological response rates. The mean reduction in serum HBV DNA from baseline to 1 and 2 years were similar in TAF and TDF group (-4.7 vs -5.1 and -5.2 vs -5.2 log10IU/mL, P=0.995). HBeAg seroconversion was 21.6% (8/37) vs 8.6% (3/35) at 2 years (P=0.191). A virological breakthrough was not seen in both groups. At year 2, mean change in eGFR was similar in both groups (TAF +4.7 mL/min vs TDF -1.4 mL/min; P=0·121), mean change in phosphorus was also similar in both group (TAF -0.05 mg/dL vs TDF -0.01 mg/dL; P=0·611). Conclusions: In patients with HBeAg positive and negative CHB, the efficacy and safety of TAF were similar to those of TDF at 2 years.

NEK7 is essential for centriole duplication and centrosomal accumulation of pericentriolar material proteins in interphase cells.

Kim, Sunghwan,Kim, Seongjae,Kim, Sungjae,Rhee, Kunsoo Cambridge University Press 2011 Journal of cell science Vol.124 No.22

<P>The centrosomes in dividing cells follow a series of cyclical events of duplication and separation, which are tightly linked to the cell cycle. Serine/threonine-protein kinase NEK7 (NEK7) is a centrosomal kinase that is required for proper spindle formation during mitosis. In this study, we observed that centriole duplication was inhibited in NEK7-depleted cells. Ectopic expression of centrosome-directed NEK7 led to the formation of extra centrioles in a kinase-activity-dependent manner. We also observed extra centriole formation in centrosome-directed NEK6-expressing cells, suggesting that NEK6 and NEK7 might share biological activities that induce centriole duplication. The centrosomal pericentriolar material (PCM) proteins were significantly reduced in NEK7-depleted cells. The PCM proteins in NEK7-depleted cells did not accumulate at the centrosomes, even if the cells exited mitosis and progressed to the G2 phase. These results revealed that NEK7 is essential for PCM accumulation in a cell cycle stage-specific manner. Furthermore, HeLa cells depleted of NEK7 during S phase retained a higher quantity of PCM proteins and exhibited a less severe mitotic phenotype. On the basis of these results, we propose that NEK7 is involved in the recruitment of PCM proteins, which are necessary for both centriole duplication and spindle pole formation. Our study revealed that NEK7 activity is required for centrosome cycle progression not only at M phase, but also at G1 phase.</P>