LED Array의 반사영상에 의한 경면체의 3차원 형상 측정

김지홍,Kim, Jee Hong 한국광학회 2016 한국광학회지 Vol.27 No.1

본 논문은 경면체의 3차원 형상을 측정하기 위한 광학시스템에 관한 것으로, 특히 LED 배열로 이루어진 점광원과 하프미러, 이미지센서로 구성된 비전시스템을 구성하여 광로분석을 수행하고 효과적인 근사화 방법을 제시한다. 실험을 통하여 취득된 영상 내의 점광원의 상대적 위치변화로부터 경면체의 3차원형상의 효과적 추정이 가능함을 보인다. An optical method to measure the three-dimensional (3D) shape of a surface with specular reflection is proposed. The proposed method is based on the analysis of the geometric path of the light from a point source, and the relative displacements of points in the reflection image. The 3D shape of a concave mirror is shown to be determined approximately via experiments, where the vision system consists of LED array illumination, a half-mirror, and an imaging sensor.

3판식 액정 프로젝션 시스템의 다이크로익 미러의 색채학적 설계

김지홍,Kim, Jee-Hong 대한전자공학회 1998 電子工學會論文誌, S Vol.s35 No.9

3판식 액정 프로젝션 시스템에서 색분리/합성용으로 사용되는 다이크로믹 미러의 새로운 설계 방법을 제안한다. 색재현 성능의 기준으로 단순히 밝거나 색순도에 근거한 방법이 아닌, 3차원 균등색공간에서의 색영역의 체적을 최대화 시키도록 설게 변수를 최적화한다. 제안된 설계 방법에서는 액정 프로젝션 시스템의 색재현의 색채학적 분석을 통해, 2개의 대표적 시청 조건에서 CIELUV 균등색공간의 재현 가능한 색영역의 체적을 최대화하도록 Dichroic Mirror/Filter의 경계 파장의 최적치가 구해진다. A new method is proposed for the design of the dichroic mirrors in 3-LCD projection systems for color separation/composition. Rather than simply basing the color performance criterion on luminance or chromatic saturation only, the optimum design parameters can be found by maximizing the perceived color gamut in a 3-D uniform color space. In this method, the half-power wavelengths were optimized by maximizing the volume of the reproducible color gamut in a CIELUV uniform color space for 2 typical viewing conditions, with proper colorimetric analysis of color reproduction in 3-LCD projection systems.

LED 반사영상을 이용한 마이크로 BGA 3차원형상검사

김지홍,Kim, Jee Hong 한국마이크로전자및패키징학회 2017 마이크로전자 및 패키징학회지 Vol.24 No.2

본 논문은 마이크로 BGA(Ball Grid Array)의 3차원 형상 검사를 위한 광학적 방법에 관한 것으로, 특히, LED를 공간적으로 배치한 광원과 경면반사특성을 이용하였다. 이를 위해 비전시스템을 구성하여 BGA의 반사영상을 취득한 후, 영상처리를 통하여 반사된 LED 점광원의 위치를 추출하여 형상검사에 이용하였다. 또한, 영상에 포함된 복수개의 BGA에 대한 상대적 위치의 통계치를 이용하여 BGA 3차원 형상의 결함을 판단하는 방법을 제안하였고, 실험을 통하여 제안된 방법의 효용성을 보였다. An optical method to inspect the 3-D shape of surface of Micro BGA is proposed, where spatially arranged LED light sources and specular reflection are considered. The reflected image captured by a vision system was analyzed to calculate the relative displacements of LED's in the image. Also, the statistics for all BGA's contained in a captured image are used together to find out the criteria for the detection of existing defects, and the usefulness of the proposed method is shown via experiments.

A Case Study on Fault Tolerant Control System for Power Plant Boiler Controller

김지홍,조현용,정명진,변증남,Kim, Jee Hong,Cho, Hyun Yong,Chung, Myung Jin,Bien, Zeungnam The Institute of Electronics and Information Engin 1987 전자공학회논문지 Vol.24 No.1

As a means of improving the reliability of a process control system, a FTCS(Fault Tolerant Control System) is designed and applied to the boiler controller of a thermal power plant. The proposed FTCS has capabilities of fault detection and diagnosis as well as back-up control and bumpless switching. A prototype of FTCS is implemented on an IBM PC as an add-on system and it is experimentally verified by using a boiler process simulator together with simplified analog controllers and a switching unit that an one-fold fault is detected in real time and back-up controller takes over the role of the original controller, controlling the faulty loop.

적자 회피 및 이익 평준화를 위한 실제 이익조정 활동

김지홍 ( Jee Hong Kim ),고재민 ( Jai Min Goh ),고윤성 ( Yun Sung Koh ) 한국회계학회 2008 회계저널 Vol.17 No.4

발생액의 질과 재무분석가의 정보 환경이 이익예측 정확도에 미치는 영향

김지홍 ( Jee Hong Kim ),백혜원 ( Hye Won Paik ),고재민 ( Jai Min Goh ) 한국회계학회 2010 회계학연구 Vol.35 No.3

재무분석가들은 공적(public) 혹은 사적(private) 경로를 통하여 기업 분석을 위한 정보를 획득한다. 그리고 이러한 정보를 해석하는 과정에서 재무분석가들의 정보는 공통 정보(common information)와 고유 정보(idiosyncratic information)로 구분된다. 즉 재무분석가들이 공적 정보인 회계정보를 동일하게 해석하는 경우 공통 정보로 구분되지만, 재무분석가별로 서로 달리 해석하는 경우 고유 정보로 구분된다. Barron et al.(1998)은 재무분석가들이 이익예측시에 사용 가능한 모든 정보를 재무분석가의 정보환경이라 정의하고, 개별 재무분석가들이 공통 정보와 고유 정보에 각각 어느 정도의 비중을 두는지를 측정하기 위해, 공통 정보 활용도(BKLS consensus) 측정치를 제안하였다. 본 연구는 이들이 제안한 측정치를 이용하여, 발생액의 질에 따라 개별 재무분석가의 공통 정보 활용도에 차이가 있는지를 살펴보고, 개별 재무분석가들의 이러한 정보 활용 행태가 재무분석가의 이익예측 정확도에 미치는 영향을 분석하였다. 본 연구 결과 첫째, 우리나라 재무분석가들은 발생액의 질이 높을수록 공통 정보의 활용 비중을 낮추는 경향을 보였다. 이는 투자자들은 양질의 정보를 제공받을 경우 재무분석가에게 이와 차별화되는 정보를 요구한다는 Indjeijikian(1991)와 같이, 재무분석가들은 투자자들의 요구에 부응하고자 고유 정보의 활용 비중을 높이는 것으로 보인다. 둘째, 재무분석가들이 공통 정보 활용 비중을 높일수록 재무분석가의 이익예측 정확도는 낮아졌다. 이는 재무분석가들이 상당한 시간과 비용을 들여 고유 정보를 수집할 때 이익예측정확도가 평균적으로 높아진다는 사실을 의미한다. 셋째, 발생액의 질이 높은 기업의 경우, 재무분석가들이 공통 정보의 활용 비중을 높일수록 이익예측 정확도는 증가하였다. 이는 회계이익의 질이 높은 기업의 경우, 수집과 해석에 시간과 비용이 소모되지 않는 공통 정보를 활용하더라도 이익예측 정확도를 향상시킬 수 있다는 사실을 의미한다. 본 연구의 결과는 발생액의 질이 높을수록 재무분석가들은 공통 정보 대신 고유 정보를 더 많이 활용하고 있지만, 이와 같은 행태가 이익예측 정확도를 높이는 데에는 도움이 되지 않음을 알 수 있다. 따라서 재무분석가들은 발생액의 질이 높은 경우 공통 정보의 활용 비중을 높이는 것이 이익예측 정확도를 높이는 효율적인 방법이 될 수 있음을 제안한다. This study examines how accruals quality and individual analysts` information environments affect on the accuracy of analysts` earnings forecasts. Barron et al.(1998) reveal about the properties of analysts` information environments, developing BKLS consensus, which is the measure of information commonality individual analysts possess at the time they announce earnings forecasts. BKLS consensus assumes analysts` information can be represented as either common to all analysts or idiosyncratic to some individual analysts. Thus, by using BKLS consensus, we can measure the degree to which analysts base their forecasts on common information relative to idiosyncratic information. Francis et al.(2005) suggest that accruals quality is a proxy for the information risk associated with earnings because this measure tells investors about the mapping of accrual-based accounting earnings into cash flows. Relatively poor accruals quality weakens this mapping and, therefore, increases information risk. First, we investigate whether accruals quality is associated with BKLS consensus, the ratio of common-to-total information in the average analysts` forecasts. Second, we examine whether analysts` behavior to change the degree of information commonality depending on accruals quality contributes to improve the accuracy of earnings forecasts. We find that higher accruals quality decreases BKLS consensus, which shows lower information risk decreases investors` demands on common information which is publicly available to all investors. Accordingly, such investors` demands enable analysts to generate more idiosyncratic information rather than common information. Our results are consistent with Indjeijikian(1991), which find that higher level of disclosures afford analysts more opportunity to develop and convey more uniquely private information in their individual forecasts. Further, we provide evidence that the accuracy of analysts` earnings forecasts decreases as BKLS consensus increases, which suggests that high ratio of common-to-total information in the average analysts` forecasts decreases analysts` earnings forecast accuracy. However, the increased reliance on common information as for firms with high accruals quality contributes to increase analysts` earnings forecast accuracy. Therefore, these findings suggest that, as for firms with high accruals quality, analysts do not have to spend their time and economic resources to acquire or develop idiosyncratic information because using common information is helpful to increase earings forecast accuracy. In sum, while analysts tend to place more reliance on idiosyncratic information rather than common information as for firms with high accruals quality, we find that their efforts on generating idiosyncratic information do not contribute to increase the accuracy of earnings forecasts. Our study suggests that it is cost effective for analysts to evaluate firms` accruals quality before they work harder to exploit more idiosyncratic information to increase the accuracy of earnings forecasts. Our results are consistent with Lobo et al.(2006) which find that low accruals quality are followed by a great number of analysts in response to greater demand on analyst services and more effort by analysts when firms have high information risk. Prior studies find that corporate disclosures are important source for analysts in forming their earnings forecasts. Byard and Shaw(2002) find that analysts rely more heavily on publicly available financial data rather than privileged communication with management. Evidence on how analysts use accounting information is still one of the main issues among those interested in understanding analysts` role as information intermediaries. Our study contributes to better understand how analysts react to market participants by analyzing that earnings forecast accuracy differs according to not only information environments but also its interaction effect with the quality of accounting information.

이익 조정 여부에 따른 발생액 이상 현상의 차이

김지홍 ( Jee Hong Kim ),고재민 ( Jai Min Goh ),김상일 ( Sang Il Kim ) 한국회계학회 2008 회계학연구 Vol.33 No.3

기존의 연구들은 발생액이 현금흐름에 비해 이익 지속성이 떨어짐에도 투자자들은 이러한 차이를 구분하지 못한다는 사실을 보여 주고 있다. 이처럼 자본시장이 발생액의 이익지속성에 대해서 과대평가하는 사실을 발생액 이상 현상이라 부르고 있다. 선행연구에서는 이와 같은 발생액 이상 현상의 가장 주된 원인으로 경영자의 이익 조정 행위를 꼽고 있다. 본 연구는 Mishkin test를 활용하여 발생액 이상 현상이 기회주의적 이익 조정에 기인하는지 검증하는 것을 목적으로 한다. 이익을 조정한 기업과 조정하지 않은 기업을 구분하여 이익 조정 기업에서 발생액 이상 현상이 더 크게 나타난다면, 자본시장이 기업의 이익 조정 행위를 가치 평가에 제대로 반영하지 못하여 발생액 이상 현상이 나타난다는 사실을 실증하는 것이다. 반대로 이익을 조정한 기업에서 발생액 이상 현상이 작게 나타난다면, 시장은 기업의 이익 조정을 효율적으로 인지하고 있으며 기능적 고착화가 발생액 이상 현상의 원인이 아님을 보여주는 것이다. 실증 분석 결과는 다음과 같다. 첫째, 전체 기업 집단에서 발생액 이상 현상은 선행연구와 일관되게 나타나고 있다. 둘째, 이익을 조정한 기업은 이익을 조정하지 않은 기업에 비해 이익 지속성이 낮게 나타났으며, 그 차이는 발생액이나 재량적발생액 항목에서 유의하다. 셋째, 발생액 이상 현상은 이익을 조정하지 않은 기업에서만 발견할 수 있고, 오히려 이익을 조정한 기업에서는 발생액 이상 현상을 관찰할 수 없었다. 본 연구는 발생액 이상 현상의 원인으로 지목되는 경영자의 기회주의적 이익 조정 여부를 명시적으로 구분하여 분석하였고, 그 결과 선행연구의 주장과는 달리 발생액 이상 현상이 이익조정의 산물이 아닐 수 있음을 보여 주었다. 따라서 발생액 이상 현상의 주된 원인으로 인정받고 있는 이익 조정에 대한 시장 비효율성의 주장에 보다 신중한 접근이 필요하다는 시사점을 제공한다. Researchers have opposite perspectives for discretionary accrual. Some support its positive aspect in that it can deliver managers` private information for future performance, having a signalling effect. On the contrary, others doubt it since it reflect managers` opportunistic earnings management. It has been the most popular metric measuring earnings management in a lot of earnings management study. Thus, discretionary accrual is still controversial among researchers. Specifically, some have a positive eye on discretionary accrual due to its additional explanation on earnings persistence, while others a negative eye because of its relatively lower explanation power than cash flow or non-discretionary accrual. In addition, some justify information content of discretionary accrual in that it explains stock returns significantly, while others belittle since the capital market overvalues it due to unawareness of earnings management. These differential perspectives are caused by earnings management. Chan et al. (2006) argued that discretionary accrual can be a leading indicator of future business if only manager does not manage earnings. Therefore, the objective of this study is to examine whether there is a difference between earnings managed firms and non-earnings managed firms after classifying earnings managed firms. Earnings management has not been clearly considered in prior studies, because they treated all firms into one portfolio. But in order to synthesize different opinions that seem to be contradictory, we attempt to divide all firms into two groups, earnings managed firms and non-earnings managed firms. After that, we investigate whether earnings persistence and market reaction are different in each group. If difference is found, we can show that discretionary accrual carries managers` private information in non-earnings managed firms, while it indicates managers` opportunistic activity in earnings managed firms. These synthetic study is carried out in two aspect, earnings persistence and market reaction. First, discretionary accrual with earnings managed firms would be able to explain future earnings relatively less, while it can account for future earnings better in non-earnings managed firms. Second, we try to investigate how the capital market evaluates each earnings persistence in two groups. Prior empirical studies have shown that market participants do not catch that the accrual is less accountable for earnings persistence than cash flow. Accruals anomaly is such a phenomenon that the stock market overvalues accrual related to earnings persistence. Studies examining accruals anomaly attributed it to market inefficiency for earnings management and functional fixation is widely regarded as a hidden driver of market mispricing. Similarly, if market cannot recognize earnings management, accruals anomaly in earnings managed firms would be bigger than in non-earnings managed firms. But if market is efficient enough, it can identify earnings managed firms and there are no accruals anomaly or it would be much smaller in earnings managed firms. This can enable us to test market inefficiency for earnings management which has been ascribed to accruals anomaly. Empirical results indicate three findings. First, accruals anomaly for total accrual and discretionary accrual is consistent with prior studies. Market overvalues earnings persistence of total accrual, non-discretionary accrual, and discretionary accrual. But Korean stock market differs from US in that undervaluing for cash flow is not significant. Second, non-earnings managed firms show more strong earnings persistence. And this is significant for both total accrual and discretionary accrual. Third, accruals anomaly exists only for non-earnings managed firms. That is, non-earnings managed firms drive market mispricing and the market has an insight into earnings management. We can synthesize opposite perspectives of prior studies through these results. First, the higher earnings persistence in non-earnings managed firms implies that its discretionary accrual has managers` private information. However, the lower earnings persistence in earnings managed firms indicates that managers abuse it to exaggerate their performance. Second, discretionary accrual in earnings managed firms cannot account for stock returns, while that in non-earnings managed firms is associated significantly. This means that market can recognize the meaning of discretionary accrual whether it is the result of earnings management. Third, a lot of researchers have conjectured that market imperfection or functional fixation is responsible for accruals anomaly. But these results are inconsistent with prior studies in that the accruals anomaly is not caused by earnings management. Therefore, we suggest that researchers should be more careful in asserting that market inefficiency for earnings management is the main cause for accruals anomaly.

특수관계자와의 거래가 이익조정 및 이익반응계수에 미치는 영향

김지홍 ( Jee Hong Kim ),우용상 ( Yong Sang Woo ) 한국회계학회 2008 회계학연구 Vol.33 No.3

본 연구는 경영자가 특수관계자와의 거래를 이용하여 이익조정을 실시하고 있는지 분석하고 투자자들은 자본시장에서 이를 어떻게 평가하는지 분석하였다. 이를 위해 2000년부터 2005년까지의 6년간의 상장기업을 대상으로 특수관계자와의 거래가 이익조정 및 이익반응계수에 미치는 영향을 살펴보았다. 연구결과 첫째, 특수관계자와의 거래금액이 클수록 재량적 발생액이 증가하는 것을 발견했다. 이는 특수관계자와의 거래가 많을수록 이익조정이 증가하는 것을 뜻한다. 둘째, 30대 대기업집단에 소속된 기업일수록 특수관계자와의 거래와 재량적 발생액 및 재량적 발생액의 절대값간의 민감도가 더 큰 것으로 나타났는데, 이는 30대대기업집단에 소속된 기업일수록 특수관계자와의 거래를 통해 이익의 상향조정을 더 많이 시도한다는 것을 의미한다. 이러한 실증분석 결과는 공정위에서 시행하고 있는 30대 대기업집단의 부당내부거래규제 장치가 유효하게 작동하고 있는지에 대한 의문을 제시하는 것이다. 셋째, 외국인지분율에 대해서는 외국인지분율이 높은 경우 특수관계자와의 거래규모가 증가함에 따라 이익의 질이 낮아지는 것을 발견했다. 이는 백원선과 조현우(2006)의 연구결과와 일치하게, 외국인투자자들이 경영자의 재량적인 이익조정을 적절하게 고려하고 있지 못한다는 증거로 해석할 수 있다. 넷째, 최대주주 및 특수관계자 지분율은 특수관계자와의 거래와 이익조정간의 관계에 유의적인 영향을 미치지 않는 것으로 나타났다. 다섯째, 투자자들이 특수관계자와의 거래에 대해 어떻게 평가하는지 검증한 결과, 특수관계자와의 거래가 많을수록 이익반응계수가 작아지는 현상을 발견했다. 이는 투자자들이 특수관계자와의 거래에 대해 부정적인 평가를 하고 있다는 것으로 해석할 수 있다. 추가적으로 투자자들은 기업이 30대 대기업집단에 속하지 않은 경우, 최대주주 및 특수관계자 지분율이 작을수록, 외국인투자자 지분율이 작을수록 특수관계자와의 거래에 대해 부정적으로 평가하고 있는 것으로 나타났다. This study examines the relationship between the transactions to the related-party and earnings management, also analyzes the effect of the transactions to the related-party on earnings response coefficient. It is easy to adjust transaction condition in the transactions to the related-party, so the transactions to the related-party will be used as a way of earnings management. If the transactions to the related-party are used as a way of earnings management, investors will estimate the transactions to the related-party negatively. The purpose of this study are analyzing whether management of company manages earnings using the transactions to the related-party discretionarily, investors recognize that the transactions to the related-party are used as a way of earnings management. This study will suggest that it is necessary to adjust the regulation of disclosure about the transactions to the related-party and to complement punishment for unfair transactions to the related-party. Moreover, this study investigates the effect of whether a company is in the 30 large enterprise groups or not, the largest stockholders ownership and the foreign stockholders ownership on the relationship between the transactions to the related-party and earnings management, market response. According to the previous studies on the relationship between the largest stockholders ownership, the foreign stockholders ownership and earnings management, the level of earnings management would be various by the largest stockholders ownership and the foreign stockholders ownership. Therefore, the largest stockholders ownership and the foreign stockholders ownership would have an effect on the relationship between the transactions to the related-party and earnings management. Because a company in the 30 large enterprise groups has more related-parties than others, this company has more chance to earnings management using the transactions to the related-party. So, earnings management using the transactions to the related-party would be more often in the 30 large enterprise groups than others. If whether a company is in the 30 large enterprise groups or not, the largest stockholders ownership and the foreign stockholders ownership have an effect on the relationship between the transactions to the related-party and earnings management, investors would consider the transactions to the related-party as a factor of impairing earnings quality and estimate the transactions to the relatedparty negatively. The sample is composed of firm years with the transactions to the related-party from 2000 to 2005. The sample firm is composed of non-financial companies which are listed in the Korea Exchange and whose fiscal year-end is December 31. Firms that are under surveillance sanction by stock exchanges or those experiencing negative stockholders equity are eliminated. All financial and stock return data are obtained via TS2000 and FN-Guide database. Finally, we eliminate those extreme observations whose values are greater than three standards deviations from the menas of all variables. The final sample consists of 1,680 firm-years. Empirical findings are as follows. First, the transactions to the related-party are significantly positively associated with discretionary accruals. This result means that the transactions to the related-party are used as a way of earnings management. Second, there is a significant positive relationship between the transactions to the related-party and the absolute value of discretionary accruals in 30 large enterprise groups. The transactions to the related-party are also significantly positively associated with discretionary accruals in 30 large enterprise groups. The relationship between the transactions to the related-party and discretionary accruals is stronger in 30 large enterprise groups than in other companies. These results mean that the companies in 30 large enterprise group manage earnings more than others using the transactions to the related-party. These results would be due to which there are many chance for the transactions to the related-party in 30 large enterprise group because companies in 30 large enterprise group have many related-parties. These results call the validity of unfair inside transaction regulation in question. Third, the transactions to the related-party are significantly positively associated with the absolute value of discretionary accruals in the high foreign stockholders ownership. Consistent with Paek and Cho(2006), this result suggests that foreign stockholders are not concerned about earnings management. Forth, the largest stockholders ownership doesn`t have an effect on the relationship between the transactions to the related-party and earnings management. Fifth, earnings response coefficient is low when the transactions to the related-party are large. This result means that investors estimate the transactions to the related-party negatively. Further, this study investigates the effect of whether a company belongs to the 30 large enterprise group or not, the largest stockholders ownership and the foreign stockholders ownership on the relationship between the trnasactions to the related-party and earnings response coefficient. The empirical results are that investors estimate the transactions to the relatedparty more negatively as not belonging to the 30 large enterprise group, the smaller the largest stockholders ownership, the smaller the foreign stockholders ownership.

노출량에 따른 디지털사진과 은염사진의 화질 비교

김지홍 ( Jee Hong Kim ),황철환 ( Cheol Hwan Hwang ) 한국사진학회 2007 AURA Vol.0 No.17

외환위기 이후의 부채비율감소와 이익조정행위에 관한 연구

김지홍 ( Jee Hong Kim ),고윤성 ( Yun Sung Koh ) 한국회계학회 2006 회계저널 Vol.15 No.2