Sources of Housing Price Fluctuations

Youngjin Hwang 한국경제연구학회 2012 Korea and the World Economy Vol.13 No.2

This article investigates the role of potential disturbances behind the housing market fluctuations in Korea using a VAR model with sign-restriction. Specifically, we identify four structural shocks, namely, i) monetary policy shock, ii) lending shock, iii) housing market shock, and iv) expectations shock, and estimate their effects on housing price and other macro variables. The overall results from impulse responses and forecast error variance decomposition indicate that development in housing sectors is closely interrelated to other macro variables/factors, including monetary policy. When we decompose the historical contribution of each shock for the actual time series movements in housing price, non-monetary policy shocks, such as lending shock and housing market shock, seem to be mainly accountable for since 2000. In this time period, loose monetary policy also partly contributed, whose role seems to be relatively minor however.

Predicting Korean Recessions with Time-Varying Predictors

Youngjin Hwang 한국경제연구학회 2015 Korea and the World Economy Vol.16 No.3

This study examines the predictive ability of a wide set of variables to predict Korean recessions based on probit models. In doing so, we extend probit-based recession forecasting models in several important and novel ways. First, in addition to commonly used financial variables, we incorporate several macro leading variables as potential predictors of recessions. Second, our forecasts use the algorithm of dynamic model selection/averaging (DMS/DMA), which allows for specific predictors to switch over time in a data-based manner. Our main findings are as follows. First, in terms of both in-sample fits and out-of-sample forecasts, while financial indicators (such as interest rate spreads) are good predictors over short-horizons (i.e., one or three months ahead), some macro leading variables (such as commodity price index and job opening-to-application ratio) turn out to be useful over longer horizons. Second, forecasting using time-varying predictors (i.e., DMS/DMA models) performs well, beating individual best predictors for each forecast horizon. In addition, we show that forecasting using switching predictors outperforms the models that employ fixed predictors and the composite leading index, in most cases, especially in terms of the mean squared error (MSE). Third, we find strong evidence for predictor switching and illustrate how the performance of the key predictors has evolved over time.

고빈도 자료를 이용한 대구·경북지역 경기분석 및 예측 : MIDAS 모형을 중심으로

황영진 ( Youngjin Hwang ) 한국경제통상학회(구 한국경상학회,한국국민경제학회) 2017 경제연구 Vol.35 No.1

지역 경제 분석에 있어 중요한 지표 중 하나로 여겨지는 지역내총생산(GRDP) 데이터는 연간 단위로 집계된다는 점과 1년 가량의 상당한 시차를 두고 공표된다는 점에서 그 유용성이 상당정도 제한적인 측면이 있다. 이 논문은 GRDP 자료와 관련된 이러한 문제를 보완하기 위해, 대구 ·경북 지역을 대상으로 혼합주기 자료의 분석에 유용한 MIDAS (Mixed Data Sampling) 모형을 다양한 월별 지표에 적용하여 다음과 같은 작업을 수행하였다: (1) 월별 GRDP 증가율의 추정, (2) 실제 GRDP 공표시점 이전에 GRDP 증가율을 추정하는 과거추정 및 (3) GRDP 증가율에 대한 단기 예측. 이러한 분석을 위해, 다양한 개별 월별 지표들 뿐 아니라, 이들로부터 추출한 동태적 요인을 이용한 모형, 개별 모형들을 바탕으로 한 다양한 모형 결합 등의 방법을 고려하였으며 이들 결과를 비교하였다. 분석 결과, 대구·경북 지역의 GRDP 증가율의 분석에 유용한 (최선의) 월별 지표들이 식별되었으나, 이들을 이용한 결과보다는 절사 평균 등의 다양한 모형 결합을 이용한 결과가 상대적으로 더 나은 것으로 나타났으며, 이를 이용한 경우 전반적으로 좋은 적합도 및 예측력을 보이는 것으로 나타났다. 반면 동태적 모형을 이용한 결과는 모형 결합에 비해 상대적으로 열등한 것으로 나타났다. The Gross Regional Domestic Product (GRDP) data are often of limited use because of their availability only at low (annual) frequency and long publication lags. This study provides a flexible framework to complement the current GRDP data of Daegu-Kyuongbuk province by combining high frequency data available for this region. Specifically, we employ the MIDAS (Mixed Data Sampling) method, which is useful for analysis of mixed frequency data, and explore a range of empirical issues including the construction of high frequency GRDP estimates, nowcasting, and short-run forecasting. We explore several model combinations and dynamic factors models as well as various individual models and compare them in terms of in-sample fit and out-of-sample forecasts. It is shown that while model combinations such as trimmed means are useful both for nowcasting and short-run forecasting, the performance of model employing dynamic factors turns out to be rather poor.

EFFICIENT AND ACCURATE FINITE DIFFERENCE METHOD FOR THE FOUR UNDERLYING ASSET ELS

( Hyeongseok Hwang ),( Yongho Choi ),( Soobin Kwak ),( Youngjin Hwang ),( Sangkwon Kim ),( Junseok Kim ) 한국수학교육학회 2021 純粹 및 應用數學 Vol.28 No.4

In this study, we consider an efficient and accurate finite difference method for the four underlying asset equity-linked securities (ELS). The numerical method is based on the operator splitting method with non-uniform grids for the underlying assets. Even though the numerical scheme is implicit, we solve the system of discrete equations in explicit manner using the Thomas algorithm for the tri-diagonal matrix resulting from the system of discrete equations. Therefore, we can use a relatively large time step and the computation of the ELS option pricing is fast. We perform characteristic computational test. The numerical test confirm the usefulness of the proposed method for pricing the four underlying asset equity-linked securities.

AI 스피커의 피드백 상황별 적합한 LED 모션 연구

황영진(Youngjin Hwang),최정민(Jungmin Choi) 한국디자인학회 2021 한국디자인학회 학술발표대회 논문집 Vol.2021 No.11

발성역치능력(Phonation Threshold Power, PTW)의 타당도 및 임상적 유용성 연구

황영진(Hwang, Youngjin),이인애(Lee, Inae) 한국음성학회 2014 말소리와 음성과학 Vol.6 No.2

This study attempted to investigate the validation of Phonation Threshold Power of Patients who have Functional voice disorder. 50 subjects participated in the study (32 subjects were patients who had functional voice disorders and 20 subjects were normal adults). The PAS (Phonatory aerodynamic system, model 6600, KAY electronics, Inc.) was used to measure the data and to do the analysis. Data from the Phonation Threshold Power was measured multiplying Phonation Threshold Pressure and Phonation Threshold Airflow. Phonation Threshold Pressure and Phonation Threshold Airflow were measured by the PAS protocol. Those were used because of the ease of phonation. The results of this study showed that the differences in Phonation Threshold Power between patients who had functional voice disorder and normal adults could become a significant index. Patients who had functional voice disorder showed more higher figures than normal adults. The results of study showed that Phonation threshold Power is more sensitive than Phonation Threshold Pressure and Phonation Threshold Airflow. The measured data also provided useful information for diagnosing patients with vocal fold.

고빈도 자료를 이용한 대구⋅경북지역 경기분석 및 예측 :

황영진(Youngjin Hwang) 한국경제통상학회 2017 경제연구 Vol.35 No.1

지역 경제 분석에 있어 중요한 지표 중 하나로 여겨지는 지역내총생산(GRDP) 데이터는 연간 단위로 집계된다는 점과 1년 가량의 상당한 시차를 두고 공표된다는 점에서 그 유용성이 상당정도 제한적인 측면이 있다. 이 논문은 GRDP 자료와 관련된 이러한 문제를 보완하기 위해, 대구⋅경북 지역을 대상으로 혼합주기 자료의 분석에 유용한 MIDAS (Mixed Data Sampling) 모 형을 다양한 월별 지표에 적용하여 다음과 같은 작업을 수행하였다: (1) 월별 GRDP 증가율의 추정, (2) 실제 GRDP 공표시점 이전에 GRDP 증가율을 추정하는 과거추정 및 (3) GRDP 증 가율에 대한 단기 예측. 이러한 분석을 위해, 다양한 개별 월별 지표들 뿐 아니라, 이들로부터 추출한 동태적 요인을 이용한 모형, 개별 모형들을 바탕으로 한 다양한 모형 결합 등의 방법을 고 려하였으며 이들 결과를 비교하였다. 분석 결과, 대구⋅경북 지역의 GRDP 증가율의 분석에 유용한 (최선의) 월별 지표들이 식별되었으나, 이들을 이용한 결과보다는 절사 평균 등의 다양한 모형 결합을 이용한 결과가 상대적으로 더 나은 것으로 나타났으며, 이를 이용한 경우 전반적으로 좋은 적합도 및 예측력을 보이는것으로 나타났다. 반면 동태적 모형을 이용한 결과는 모형 결합에 비해 상대적으로 열등한 것으로 나타났다. The Gross Regional Domestic Product (GRDP) data are often of limited use because of their availability only at low (annual) frequency and long publication lags. This study provides a flexible framework to complement the current GRDP data of Daegu-Kyuongbuk province by combining high frequency data available for this region. Specifically, we employ the MIDAS (Mixed Data Sampling) method, which is useful for analysis of mixed frequency data, and explore a range of empirical issues including the construction of high frequency GRDP estimates, nowcasting, and short-run forecasting. We explore several model combinations and dynamic factors models as well as various individual models and compare them in terms of in-sample fit and out-of-sample forecasts. It is shown that while model combinations such as trimmed means are useful both for nowcasting and short-run forecasting, the performance of model employing dynamic factors turns out to be rather poor.

Carbon Nanotube Film for Stretchable Conductor

Youngjin Jeong,Yunjea Hwang,Seunghyuk Lee,Yeonjae Oh,Hyunwoong Oh 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Interpretations on principal components analysis of head-related impulse responses in the median plane.

Hwang, Sungmok,Park, Youngjin American Institute of Physics for the Acoustical S 2008 Journal of the Acoustical Society of America Vol.123 No.4

<P>A principal components analysis of the median-plane head-related impulse responses (HRIRs) in the CIPIC HRTF database reveals that the individual HRIRs can be reconstructed by a linear combination of 12 principal components (PCs) within 5% of error in the least-squares sense. The PCs include the intersubject and interelevation variations in the median-plane HRIRs. Each PC provides sound cues for the front-back discrimination and/or the vertical perception. There exist common systematic elevation dependencies in the weights of lower-numbered PCs which contribute to the pinna/head diffractions, whereas the elevation dependencies in the weights of higher-numbered PCs are different from subject to subject.</P>

Prediction of Chiral Discrimination by β-Cyclodextrins Using Grid-based Monte Carlo Docking Simulations

Youngjin Choi,Dong Wook Kim,Hyungwoo Park,Suntae Hwang,Karpjoo Jeong*,Seunho Jung* 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.5