Overestimation of Radioactivity Concentration of Difficult-To-Measure Radionuclides in Scaling Factor Methodology

Park, Junghwan,Kim, Tae-Hyeong,Lee, Jeongmook,Kim, Junhyuck,Kim, Jong-Yun,Lim, Sang Ho Korean Radioactive Waste Society 2021 방사성폐기물학회지 Vol.19 No.3

The overestimation and underestimation of the radioactivity concentration of difficult-to-measure radionuclides can occur during the implementation of the scaling factor (SF) method because of the uncertainties associated with sampling, radiochemical analysis, and application of SFs. Strict regulations ensure that the SF method as an indirect method does not underestimate the radioactivity of nuclear wastes; however, there are no clear regulatory guidelines regarding the overestimation. This has been leading to the misuse of the SF methodology by stakeholders such as waste disposal licensees and regulatory bodies. Previous studies have reported instances of overestimation in statistical implementation of the SF methodology. The analysis of the two most popular linear models of the SF methodology showed that severe overestimation may occur and radioactivity concentration data must be dealt with care. Since one major source of overestimation is the use of minimum detectable activity (MDA) values as true activity values, a comparative study of instrumental techniques that could reduce the MDAs was also conducted. Thermal ionization mass spectrometry was recommended as a suitable candidate for the trace level analysis of long-lived beta-emitters such as iodine-129. Additionally, the current status of the United States and Korea was reviewed from the perspective of overestimation.

가결산 순이익의 과대공시와 기업특성 및 시장의 사후 감시기능

전영순 ( Young Soon S. Cheon ),손준희 ( Joon Hee Sohn ) 한국회계학회 2005 회계학연구 Vol.30 No.2

최근 들어 상당수의 기업들이 정기주총일 전에 경제신문 등 신문매체를 통해 가결산정보를 자발적으로 공시하고 있다. 선행연구는 신문매체를 통해 자발적으로 사전공시되는 가결산 순이익이 사후 확정되는 순이익에 비해 과대 공시되는 경향이 있음을 보고하였다. 이처럼 가결산 순이익이 사후적으로 확정되는 순이익에 비해 과대 공시되는 것은 경영자의 의도적인 결정에 의한 것일 수도 있지만, 결산과정의 최종단계에서 수행되는 수정분개 등을 통해 그 숫치가 달라질 수도 있기 때문이다. 따라서 본 연구에서는 가결산 순이익의 과대 공시가 특정 기업특성과 체계적으로 관련되어 있는지를 검토한다. 실증분석 결과, 가결산 순이익을 과대 공시하는 기업은 일정한 특성을 보이는 것으로 나타난다. 기업규모가 작을수록, 기업의 경영성과가 열악할수록, 결산과정의 마지막 단계에서 결정되는 유가증권평가손실 등이 매출액에서 차지하는 비율이 큰 기업일수록 가결산 순이익을 과대 공시하는 경향이 있다. 또한, 경영자를 견제할 수 있는 외국인지분이 높을수록 기업은 가결산 순이익의 과대 공시를 회피하는 것으로 나타난다. 1998년 이전에는 가결산 순이익이 과대 공시된 것으로 밝혀지더라도 주식시장에서의 불이익은 주어지지 않았다. 그러나 1999년 이후에는 약하지만 사후 실적치 대비 가결산 순이익의 오차가 커질수록 부정적인 주가반응이 나타난다. 아울러 외국인지분율이 높을수록 과대 공시된 가결산 순이익에 대한 주식시장의 불이익은 가중된다. 1999년 이후에는 외국인투자자가 가결산 순이익의 과대 공시에 대한 감시기능을 수행하고 있음을 의미한다. This study examines characteristics of firms that announce optimistic preliminary earnings announcements. Many firms voluntarily announce preliminary earnings information before actual earnings are finalized at the general shareholder meeting. Prior research suggests that such preliminary earnings are optimistic compared to actual earnings. Preliminary earnings announcements are voluntary disclosures. Thus, it is possible that management has incentives to overestimate the forthcoming earnings if there is no penalty for the overestimation. Also, preliminary earnings announcements are usually made before the actual earnings are finalized. Hence, preliminary earnings announcements can turn out to be optimistic if items recognized through adjusting entries in the closing process affect actual earnings. The study investigates firm characteristics that are systematically associated with optimistic preliminary earnings announcements. Furthermore, the study examines whether the stock market plays a monitoring role against optimistic preliminary earnings announcements. Specifically, it is hypothesized that optimistic preliminary earnings announcements are negatively associated with firm size, equity holdings by foreign and domestic institutional investors, and firm performance. Furthermore, it is expected that optimistic preliminary earnings announcements are positively related to items recognized through year-end adjusting entries, such as bad debt expenses and losses or gains from the equity method. Whether preliminary earnings information is overestimated is proved when actual earnings are disclosed later. Thus, if the market penalizes preliminary earnings information that turns out to be overestimated, the market reaction to the actual earnings announcement will be negative. We test whether the market penalizes preliminary earnings information that turns out to be overestimated by examining market reactions to actual earnings announcements. As expected, we find that firms tend to overestimate preliminary earnings information as they are small, perform poorly, and have relatively large items recognized through year-end adjusting entries. The results also reveal that firms are likely to avoid optimistic preliminary earnings announcements as equity ownership held by foreign investors is high. There was no penalty for optimistic preliminary earnings announcements before 1998. However, there is evidence, although it is weak, the markets penalize firms when the preliminary earnings information turns out overestimated. Furthermore, the penalization of the market increases with foreign equity ownership in the firm.

국내 원자력발전소 지진 PSA의 CDF 과평가 방지를 위한 비희귀사건 모델링 방법 연구

임학규,Lim, Hak Kyu 한국안전학회 2021 한국안전학회지 Vol.36 No.5

Calculating the scrutable core damage frequency (CDF) of nuclear power plants is an important component of the seismic probabilistic safety assessment (SPSA). In this work, a simple approach is developed to calculate CDF from minimal cut sets (MCSs) with non-rare events. When conventional calculation methods based on rare event approximations are employed, the CDF of industry SPSA models is significantly overestimated by non-rare events in the MCSs. Recently, quantification algorithms using binary decision diagrams (BDDs) have been introduced to prevent CDF overestimation in the SPSA. However, BDD structures are generated from a small part of whole MCSs due to limited computational memory, and they cannot be reviewed due to their complicated logic structure. This study suggests a simple approach for scrutinizing the CDF calculation based on whole MCSs in the SPSA system analysis model. The proposed approach compares the new results to outputs from existing algorithms, which helps in avoiding CDF overestimation.

또래관계에 대한 자기평가편향과 주관적 안녕감, 대인행동의 관계: 적정한계선 가설의 검증

이은주,염혜선 한국심리학회산하학교심리학회 2020 한국심리학회지 학교 Vol.17 No.3

The purpose of this study was to explore how overly positive self-estimations in peer relationships relate to subjective well-being and to the occurrence of interpersonal behaviors supporting basic psychological needs among elementary school students. This study tested the optimal margin hypothesis of positive illusion by examining the curvilinear relationship between these variables. The sample consisted of 346 fifth and sixth grade students. The self-criterion residual method was used to derive self-estimation bias scores by regressing the real peer relations index (i.e., In-degree) on their perceived peer relationship qualities. The results showed that girls more strongly overestimated the quality of their peer relationships than boys. Self-estimation biases had a positive curvilinear relationship with negative affects and a negative curvilinear relationship with relatedness needs supporting interpersonal behaviors. These results supported the existence of the optimal margin of positive illusion because overestimations of the quality of peer relationships were associated with lower levels of negative affects and relatedness needs-supporting interpersonal behaviors, though these benefits flattened out and no further benefit was observed after an optimal level of overestimation. However, self-estimation bias was linearly associated with positive affect, autonomy needs-supporting interpersonal behaviors, and competence needs-supporting interpersonal behaviors. These results indicated that optimal margin hypothesis was not supported for all outcome variables. 본 연구는 실제 또래관계에 비해 자신의 또래관계를 긍정적으로 편향되게 지각하는 경향이 주관적 안녕감 및 기본심리욕구 지지적인 대인행동과 어떠한 관계가 있는지 규명하는데 목적이 있었다. 특히 긍정적 착각의 적정한계선 가설을 검증하기 위해 자기평가편향이 이들 변인과 곡선관계가 있는지 살펴보고자 하였다. 이를 위해 초등학교 5, 6학년 346명을 대상으로 또래관계에 한정된 영역특수적 자기평가와 그에 상응하는 객관적 또래관계 지표인 내향중심성을 준거로 자기평가편향을 측정하였다. 연구결과, 또래관계에 대한 자기평가편향은 남학생에 비해 여학생에게서 유의미하게 높은 것으로 나타났다. 이러한 자기평가편향은 부정정서와 유의미한 정적 곡선관계, 관계성지지 대인행동과 유의미한 부적 곡선관계가 있는 것으로 나타났다. 이는 긍정적 착각의 적정한계선 가설이 의미하는 바와 같이, 긍정적 자기평가편향이 높을수록 부정정서는 낮고 대인관계에서 타인의 관계성 욕구를 지지하는 대인행동을 많이 하지만, 자기평가편향이 적정 수준을 넘어서면 오히려 부정정서는 높아지고 관계성 지지행동은 더 이상 증가하지 않음을 의미한다. 그러나 긍정정서, 유능성지지 대인행동, 자율성지지 대인행동에 대해 정적 선형관계를 나타낸바, 긍정적 착각의 적정한계선 가설이 모든 결과변인에 해당하는 것은 아니었다. 연구의 의의 및 후속연구를 위한 제언이 논의되었다.

Risk of Overestimation of Renal Function Using Estimated GFR in Patients with Liver Cirrhosis

( Jeong-juyoo ),( Sang Gyune Kim ),( Young Seok Kim ),( Bora Lee ),( Soung Won Jeong ),( Jae Young Jang ),( Sae Hwan Lee ),( Hong Soo Kim ),( Young Don Kim ),( Gab Jin Cheon ),( Boo Sung Kim ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: In the clinical context of the patients with liver cirrhosis, accurate evaluation of the renal function is potentially crucial. Serum creatinine (SCr) is widely used to estimate glomerular fitration rate (GFR), but discrepancy between measured GFR (mGFR) and estimated GFR (eGFR) in cirrhotic patients has not been evaluated yet. In this study, we compared performance of two common eGFR formula compared with mGFR, and evaluated factors associated with overestimation of renal function in cirrhotic patients. Methods: This retrospective study included consecutive 458 patients who were diagnosed as liver cirrhosis. 51Cr-EDTA was used for assessing actual GFR and eGFR was calculated by two different formulas; i) Modification of Diet and Renal Disease equation (MDRD), ii) CKD-EPI cystatin C equation. eGFR increase by more than 10% of mGFR in each patient was defined as overestimation of GFR. Sarcopenia was defined as an L3 skeletal muscle index of ≤38.5cm2/m2 for women and ≤52.4 cm2/m2 for men using computed tomography. Logistic regression was used to evaluate factors associated with overestimation of renal function. Results: Mean age of the patients was 53.6±11.5 years and 76.6% were male. Mean SCr was 1.1±0.9mg/dL, and the mean eGFR was 81.8±25.8ml/min by MDRD and 87.3±29.9ml/min by cystatin C. The mean mGFR was 76.0±26.6ml/min, which was significantly lower than eGFR. Cystatin C-eGFR showed better correlation and performance with mGFR compared with MDRD-eGFR (R 0.58 vs. R 0.48). MDRD-eGFR overestimated mGFR among 47% of the patients with liver cirrhosis. A multivariate analysis showed that male gender (hazard ratio [HR〕 1.63, 95% confidence interval [CI〕 1.03-2.56; P=0.04) and Child-Pugh class (HR 3.3, 95% CI 1.89-5.80; P<0.001) were independent risk factors associated with overestimation of renal function, but not associated with sarcopenia (HR 1.1, 95% CI 0.56-2.36; P=0.09). Conclusions: In patients with cirrhosis, overestimation of the GFR is common when using SCr and creatinine clearance. Isotopic measurement of GFR or eGFR by cystatin C rather than SCr can be more useful when greater accuracy is required, especially in patients with impaired liver function or male gender.

아동의 자기과대평가의 적응적 가치

신혜은,David, F. Bjorklund 한국심리학회 산하 한국발달심리학회 2005 한국심리학회지 발달 Vol.18 No.4

Two studies investigated the functional value of children's poor metacognition by examining how adults perceive such self-overestimation. In Study 1, adults read scenarios about 7- and 10-year-old children who were either accurate or overestimated their performance on a memory task. They were then asked to rate these hypothetical children in terms of intellectual, social, and personality characteristics. Parents and teachers thought that the young children who overestimated their performance were more vulnerable, helpless, and imaginative, but less smart and independent than accurate one. In Study 2, adults were asked which of two children (one who overestimated his/her performance and one who was accurate) they would prefer to baby sit for. Although adults chose the accurate and overestimating children with comparable frequency, they professed different reasons for their choices. Moreover, this tendency varied with children's age. We suggest that children's overestimation of their ability may reflect an ontogenetic adaptation, which serves an adaptive function early in development, in part, by endearing them to adults. 본 연구의 목적은 아동기 사고의 전형적인 특성인 사고의 정적 편향성, 즉 자기과대평가의 적응적 가치를 분석해 보는 것이었다. 설문지를 통해 성인들이 아동의 자기과대평가를 어떻게 지각하고 있으며, 성인의 지각이 실제 양육 행동에 어떠한 영향을 줄 것인지 예측해봄으로써 자기과대평가의 사회 정서적 측면에서의 적응적 가치를 알아보았다. 연구 1에서는 자신의 수행을 지나치게 과대평가하거나 비교적 정확하게 평가하는 두 유형의 7세, 10세 아동에 대한 이야기를 성인에게 제시한 후, 각 아동에 대한 성인의 주관적인 느낌을 평가하게 하였다. 결과, 성인들은 어린 아동의 과대평가를 긍정적으로 지각하고 있었으며 아동의 자기과대평가는 보호하거나 돌봐주고 싶은 느낌을 이끌어 내는 것으로 나타났다. 연구 2에서는 성인으로 하여금 아동을 한명을 돌봐야 하는 가설적인 상황에서 과대평가 아동과 근접평가 아동 중 어떤 아동을 돌보고 싶은지 선택하게 하였고, 그 이유를 물어보았다. 결과 10세 아동의 경우는 근접평가 아동의 피 선택 비율이 유의하게 높았던 반면, 7세 아동의 경우는 유형에 따른 선택 빈도에 차이가 없었다. 그러나 선택의 이유에서는 유형에 따른 차이가 유의했다. 논의에서는 아동기 과대평가의 적응적 가치를 진화 발달적 관점에서 논의하였다.

Analysis and Probability of Overestimation by an Imperfect Inspector with Errors of Triangular Distributions

Moon Hee Yang(양문희),Jae Hyung Cho(조재형) 한국산업경영시스템학회 2018 한국산업경영시스템학회지 Vol.41 No.2

There always exist nonzero inspection errors whether inspectors are humans or automatic inspection machines. Inspection errors can be categorized by two types, type I error and type II error, and they can be regarded as either a constant or a random variable. Under the assumption that two types of random inspection errors are distributed with the “uniform” distribution on a half-open interval starting from zero, it was proved that inspectors overestimate any given fraction defective with the probability more than 50%, if and only if the given fraction defective is smaller than a critical value, which depends upon only the ratio of a type II error over a type I error. In addition, it was also proved that the probability of overestimation approaches one hundred percent as a given fraction defective approaches zero. If these critical phenomena hold true for any error distribution, then it might have great economic impact on commercial inspection plans due to the unfair overestimation and the recent trend of decreasing fraction defectives in industry. In this paper, we deal with the same overestimation problem, but assume a “symmetrical triangular” distribution expecting better results since our triangular distribution is closer to a normal distribution than the uniform distribution. It turns out that the overestimation phenomenon still holds true even for the triangular error distribution.

Analysis and Probability of Overestimation by an Imperfect Inspector with Errors of Triangular Distributions

양문희,조재형 한국산업경영시스템학회 2018 한국산업경영시스템학회지 Vol.41 No.2

There always exist nonzero inspection errors whether inspectors are humans or automatic inspection machines. Inspection errors can be categorized by two types, type I error and type II error, and they can be regarded as either a constant or a random variable. Under the assumption that two types of random inspection errors are distributed with the “uniform” distribution on a half-open interval starting from zero, it was proved that inspectors overestimate any given fraction defective with the probability more than 50%, if and only if the given fraction defective is smaller than a critical value, which depends upon only the ratio of a type II error over a type I error. In addition, it was also proved that the probability of overestimation approaches one hundred percent as a given fraction defective approaches zero. If these critical phenomena hold true for any error distribution, then it might have great economic impact on commercial inspection plans due to the unfair overestimation and the recent trend of decreasing fraction defectives in industry. In this paper, we deal with the same overestimation problem, but assume a “symmetrical triangular” distribution expecting better results since our triangular distribution is closer to a normal distribution than the uniform distribution. It turns out that the overestimation phenomenon still holds true even for the triangular error distribution.

위협의 과대평가와 기억신뢰가강박적 확인행동에 미치는 영향

이상원,박준호,이민규 한국청소년학회 2020 청소년학연구 Vol.27 No.11

This study established a two-way interaction hypothesis that the effect of overestimating threats on compulsive checking behaviors depends on the level of memory confidence, and this was verified through experiment. It was a completely randomized design of 2 (memory confidence: high/low) x 2 (overestimation of threat: high/low), and seventy-five undergraduates participated. To test the hypotheses, a 2x2 ANOVA, with memory confidence (high/low) and overestimation of threat (high/low), as between-participants factors was performed on the checking behavior. Participants were randomly assigned to one of the four experimental conditions. As a result of the study, the hypothesis was supported as the interaction effect of the overestimation of threat and memory confidence was significant on the checking behavior. Specifically, in the group with low memory confidence, the group with the high overestimation of threat had significantly more checking behavior than the group with the low. In contrast, In the group with high memory confidence, the difference between the group with high and low overestimation of threat was not significant. The implications and limitations of this study and the direction of future research were discussed. 본 연구는 기억신뢰의 수준에 따라서 위협의 과대평가가 강박적 확인행동에 미치는 영향이 달라진다는 이원상호작용 가설을 세웠으며 이를 실험을 통해 검증했다. 2 (기억신뢰: 고/저) x 2 (위협의 과대평가: 고/저)의 완전무선설계였으며 대학생 75명이 참가했다. 먼저, 자신의 수행으로 인해 일어날 수 있는 위협적 사건의 발생확률과 심각도를 제시한 다음 예비 분류과제와 기억과제를 수행하도록 하였다. 수행 직후 기억과제에 대한 기억점수를 제시한 다음 본 분류과제와 기억과제를 수행하도록 하고, 수행에서 나타난 확인행동을 측정하였다. 연구 결과, 확인행동에 기억신뢰와 위협의 과대평가의 이원상호작용효과가 유의하여 가설이 지지되었다. 구체적으로, 기억신뢰가 낮은 집단에서는 위협의 과대평가가 높은 집단이 낮은 집단보다 확인행동이 유의하게 많았다. 반면 기억신뢰가 높은 집단에서는 위협의 과대평가가 높은 집단과 낮은 집단의 차이가 유의하지 않았다. 결과를 토대로 본 연구의 시사점과 제한점 및 장래연구 방향을 논의했다.

FPIA에 의한 vancomycin 혈장 농도의 과측정

박선영,김민정,김귀숙,손인자,서옥경 한국병원약사회 2003 병원약사회지 Vol.20 No.3

Vancomycin is eliminated mainly through the kidneys. As this drug is potentially nephro- and ototoxic in patients with renal insufficiency, quantitation of its levels in patient blood is required to maintain therapeutic level. While using FPIA, there have been reports regarding possible interference by vancomycin breakdown product(CDP-1) that accumulates in patients with renal failure. The purpose of this study was to evaluate the perfomance of FPIA assay in comparison to HPLC with vancomycin level, especially related to renal function and duration of treatment. Total 53 adult patients receiving vancomycin with measurement of vancomycin levels from July to September 2002 were achieved in the study. All serum samples were analyzed initially by FPIA(Abbott TDx) and again by HPLC. When measured by FPIA as compared with HPLC, mean values were overestimated by 26.4·23.4% (-38.6 ~ 78.2%). No association was found between the overestimation and the renal function, duration of the therapy, and TDx concentration. If reported concentrations are falsey elevated, the potential for underdosing and therapeutic failure is of obvious concern. In our study, vancomycin levels were generally overestimated when measured using FPIA. Further controlled studies should be performed in a larger population to document the vancomycin overestimation and its relationship to other factors.