非對稱 情報 資本市場에서 企業의 批判과 配當信號政策

李兪浩,車殷泳 한국경제학회 2002 經濟學硏究 Vol.50 No.4

이 논문은 자본시장에서 기업배당 공시의 진실성에 대한 시장의 평판과 배당의 미래 수익에 대한 신호 효과를 동시에 고려하는 경영자의 투자-재무 의사결정을 기업가치 극대화 모형을 통해 분석하고 있다. 주식 발행시 정보 비대칭성으로 인한 레몬 프리미엄을 부담하는 상황에서, 경영자는 배당률 인상에 따른 발행주가 상승의 이익과 신호에 따르는 평판 변화의 효과가 한계적으로 일치하는 수준에서 최적 배당률을 결정한다. 정보의 비대칭성 및 경영자가 시장을 속일 수 있는 기능성의 존재로 인해, 합리적 기대 균형하의 시장 주가는 완전정보일 때에 비해 더 낮게 형성되며 그 영향으로 과소투자가 이루어지게 된다. This paper develops a model that corporate managements try to maximize incumbent equityholders' wealth in asymmetrically informed capital markets, where firms should bear lemons premium at issuing stocks and dividends has announcement effect on the corporate future cash flow. A corporate manager should consider the marginal increase of stock price and the marginal change of its reputation when increasing cash dividends. When s/he increases dividends, outside investors doubt whether it is true or false signaling. Because of lemons premium and probability of investors being cheated by false signaling, equilibrium stock price formed through rational expectations turns to be set below that of perfectly informed capital markets. It results in underinvestment. That is, corporate investment is done less than the Fisherian optimum level of investment. The better reputation in its truthfulness of announcement a firm has, the less cost due to the problem of time inconsistency it could bear.

A Generalization of the Schur-Cohn Test

이유호 호남수학회 2007 호남수학학술지 Vol.29 No.4

In this note we provide a generalization of the Schur-Cohntest. Ifpn be a polynomial of degree n then pn is a reduced-stable polyno-mial whose reduced degree is equal to r if and only if Dn := Pn Q1n is acontraction such that rank(I Dn D n ) = r.

신장이식에서 대사체 연구

이유호,이상호 대한이식학회 2015 Korean Journal of Transplantation Vol.29 No.2

Acute and chronic immune injury, drug toxicity, and cardiovascular complications remain a critical challenge following kidney transplantation. Success from these hurdles is closely associated with the ability to monitor patients and responsively adjust their medication. Metabolic and biochemical profiling (metabolomics) may enable detection of early changes in cell signal transduction regulation and biochemistry with high sensitivity and specificity. However, metabolomics have not been studied extensively in the field of kidney transplantation. This review describes the basic principles of metabolomics, summarizes recent studies, and suggests future perspectives. 대사체학(metabolomics)은 세포 과정(Cellular process) 중 발생하는 소분자 대사산물 전체(대사체; Metabolome) 에 대하여 종합적인 연구를 하는 학문으로 정의한다. mRNA 발현을 연구하는 전사체학(transciptomics), 단백질의 변화와 기능을 연구하는 단백질체학(proteomics)과 함께 생명체내 변화를 총체적으로 이해할 수 있는 학문으로특히 전사체 또는 단백질이 제공하지 못하는 어떠한 특정순간에 세포 내에서 일어나는 생리학적, 대사적, 화학적현상에 대한 정보를 분석할 수 있는 장점을 가지고 있다(1). 인체의 세포, 조직, 체액에 존재하는 저분자 화합물(분자량 100∼1,000)들을 전체적으로 분석하기 위해서는이들을 적절히 분리하고 탐지할 수 있는 분석기술과 다양한 통계적 방법을 사용하여 대사체를 확인하고 분석하는생명정보학 기술이 요구된다. 현재 40,000종이 넘는 인간대사체 정보 및 이중질량분석(Tandem mass) 스펙트럼 데이터가 축적되어 있으며 인체 검체를 활용한 연구 경험이축적되면서 의약품의 독성연구, 질병진단을 위한 바이오마커 연구로 대사체학 연구가 다양하게 접목되고 있다. 바이오마커 개발 연구는 정상 상태 및 질병 상태의 대사체 양상(profile)을 비교해서 질병상태에서 변화되는 주요대사체들을 검출 및 규명함으로써 질병의 조기진단 및 새로운 병태생리 및 치료 표적을 규명하고자 함이 주요 목적이며 현재 다양한 질병 모델과 인체 유래물 검체에 대사체학의 활용이 증가하고 있다. 이식분야에서 대사체 연구는아직 초기 단계로 면역억제제 대사 이상 또는 급성 거부반응의 진단분야에서 활용 가능성이 최근 제시되고 있다. 본 논문에서는 대사체학 연구의 기본 개념을 소개하고 신장 이식 분야에서의 연구 현황과 향후 활용방안 등을 소개하고자 한다.

융합교육 프로그램을 활용한 자기주도적 기술학습 마인드 기르기

이유호 한국미래교육학회 2013 미래교육연구 Vol.3 No.3

이 연구는 융합교육 프로그램을 활용하여 중학교 2학년 168명을 대상으로 기술·가정교육의 필요성, 이해도, 흥미도, 참여도와 모둠협동학습에 의한 발표력, 리더십 향상도, 교육효과를 그리고, 융합교육과 융합교육의 효과에 대하여 사전 실태조사를 하여 기술·가정 교과수업에 학생들이 가장 원하는 수업형태를 조사하고 다른 교과와 연계시켜 지도함으로써 융합적 사고와 스스로 문제를 해결할 수 있는 능력인 자기주도적 학습 마인드를 기르는데 목적이 있다. The purpose of this study was to develop integrated thinking ability and problem-solving capability of self directed learning for students through integrating subjects. This study was to survey about necessity of techno;ogy home economics, understanding, interest, participation, speech ability by cooperative education, leadership improvement, educational effects, effects of integrated education. This study was to survey form of a technology home economics that were expected by middle school students.

NEW EXACT TRAVELLING WAVE SOLUTIONS OF SOME NONLINEAR EVOLUTION EQUATIONS BY THE (G'/G)-EXPANSION METHOD

이유호,이미혜,안재영 호남수학회 2011 호남수학학술지 Vol.33 No.2

In this paper, the (G'/G)-expansion method is used to construct new exact travelling wave solutions of some nonlinear evolution equations. The travelling wave solutions in general form are expressed by the hyperbolic functions, the trigonometric functions and the rational functions, as a result many previously known solitary waves are recovered as special cases. The (G'/G)-expansion method is direct, concise, and effective, and can be applied to many other nonlinear evolution equations arising in mathematical physics.

깊이별 분리 가능 U-Net을 이용한 아틀라스 비디오 초해상화 방법

이유호,윤국진,정원식,전동산,서정일 한국멀티미디어학회 2023 멀티미디어학회논문지 Vol.26 No.12

As high quality media demand, deep learning based super-resolution methods have shown the visual performance improvements to create high resolution (HR) videos from low resolution (LR) videos. In this study, we propose a altas video super-resolution method using depth-wise separable u-net, so called DSUN. In order to evaluate the super-resolution performance, we used the atlas, reds, vimeo-90k test dataset. In the experimental results, DSUN demonstrated high performance across all dataset compared to the state-of-the-art methods.

Validation Study of an Operational Tolerance Signature in Korean Kidney Transplant Recipients

이유호,서정우,김양균,문주영,김진석,정경환,김보미,김경운,양철우,김찬덕,박재범,김영훈,정병하,이상호 대한면역학회 2018 Immune Network Vol.18 No.5

Operational tolerance (OT), defined as maintaining stable graft function without immunosuppression after transplant surgery, is an ideal goal for kidney transplant recipients (KTRs). Recent investigations have demonstrated the distinctive features of B cells, T cells, and dendritic cell-related gene signatures and the distributions of circulating lymphocytes in these patients; nonetheless, substantial heterogeneities exist across studies. This study was conducted to determine whether previously reported candidate gene biomarkers and the profiles of lymphocyte subsets of OT could be applied in Korean KTRs. Peripheral blood samples were collected from 153 patients, including 7 operationally tolerant patients. Quantitative real-time PCR and flow cytometry were performed to evaluate gene expression and lymphocyte subsets, respectively. Patients with OT showed significantly higher levels of B cell-related gene signatures (IGKV1D-13 and IGKV4-1), while T cell-related genes (TOAG-1) and dendritic cell-related genes (BNC2, KLF6, and CYP1B1) were not differentially expressed across groups. Lymphocyte subset analyses also revealed a higher proportion of immature B cells in this group. In contrast, the distributions of CD4+ T cells, CD8+ T cells, mature B cells, and memory B cells showed no differences across diagnostic groups. An OT signature, generated by the integration of IGKV1D-13, IGKV4-1, and immature B cells, effectively discriminated patients with OT from those in other diagnostic groups. Finally, the OT signature was observed among 5.6% of patients who had stable graft function for more than 10 years while on immunosuppression. In conclusion, we validated an association of B cells and their related signature with OT in Korean KTRs.

압축 왜곡 감소를 위한 CNN 기반 이미지 화질개선 알고리즘

이유호,전동산 한국멀티미디어학회 2022 멀티미디어학회논문지 Vol.25 No.5

As realistic media are widespread in various image processing areas, image or video compression is one of the key technologies to enable real-time applications with limited network bandwidth. Generally, image or video compression cause the unnecessary compression artifacts, such as blocking artifacts and ringing effects. In this study, we propose a Deep Residual Channel-attention Network, so called DRCAN, which consists of an input layer, a feature extractor and an output layer. Experimental results showed that the proposed DRCAN can reduced the total memory size and the inference time by as low as 47% and 59%, respectively. In addition, DRCAN can achieve a better peak signal-to-noise ratio and structural similarity index measure for compressed images compared to the previous methods.

Thermal Shock Fracture of Silicon Carbide and its Application to LWR Fuel Cladding Performance During Reflood

이유호,Thomas J. Mckrell,Mujid S. Kazimi 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.6

SiC has been under investigation as a potential cladding for LWR fuel, due to its high melting point and drasticallyreduced chemical reactivity with liquid water, and steam at high temperatures. As SiC is a brittle material its behavior duringthe reflood phase of a Loss of Coolant Accident (LOCA) is another important aspect of SiC that must be examined as part ofthe feasibility assessment for its application to LWR fuel rods. In this study, an experimental assessment of thermal shockperformance of a monolithic alpha phase SiC tube was conducted by quenching the material from high temperature (up to1200ºC) into room temperature water. Post-quenching assessment was carried out by a Scanning Electron Microscopy (SEM)image analysis to characterize fractures in the material. This paper assesses the effects of pre-existing pores on SiC claddingbrittle fracture and crack development/propagation during the reflood phase. Proper extension of these guidelines to anSiC/SiC ceramic matrix composite (CMC) cladding design is discussed.

Bayesian Multiple Changepoints Detection for the Power Law Process with Binary Segmentation Procedures

이유호 장전수학회 2010 Proceedings of the Jangjeon mathematical society Vol.13 No.2

We consider a power law process assumed to have multiple changepoints. We propose a binary segmentation procedure for locating changepoints. We select one model between no-changepoint model and changepoint model by the Bayes factor. We repeat this procedure until no more changepoint is found. Then we carry out a multiple test with the Bayes factor through the intrinsic priors of Berger and Pericchi (1996) to investigate the system behaviour of failure times. We demonstrate our results with a real dataset and some simulated datasets.