긍정문항과 부정문항으로 이루어진 심리검사에 대한 방법효과 검증

이현정,홍세희,조기현 한국교육방법학회 2019 교육방법연구 Vol.31 No.1

In order to reduce agreement bias(acquiescence) that occurs when respondents agree regardless of questions in survey, negatively- and positively-worded items are often mixed. However, methods effects can be caused from the mixed format and the effects leads to problems in test validity. Using tests with negatively- and positively-worded items, the present study examined whether theoretical factors a test tried to measure and method-effect factors could be distinguished. For this purpose, self-esteem and peer relationship scales were used for elementary, middle and high school groups respectively, and analyzed applying confirmatory factor analysis. Results showed that CTCM and CTCU models considering methods effects fitted well. However, for the self-esteem scale, methods effects appeared for negatively-worded items while for the peer relationship scale, methods effects appeared for positively-worded items. The significance of this study indicates that it is necessary to consider methods effects when exploring the factor structure of a test with negatively- and positively-worded items in a mixed format. This study also suggests further investigations regarding method effects using various tests in future studies to generalize current results. 자기보고식 검사에서는 문항 내용과 상관없이 동의하려는 경향인 동의편파(묵종)를 줄이기 위해 긍정문항과 부정문항을 혼용하여 사용하게 되는데, 이 때 의도치 않은 방법효과가 발생하여 검사의 타당성을 저해할 수 있다. 따라서 본 연구는 긍정문항과 부정문항이 함께 쓰인 검사에서 문항 표현에 따른 방법효과를 분석하여 검사가 측정하고자 하는 실제적 요인과 방법효과 요인이 구분될 수 있는지 알아보고자 하였다. 이를 위해 자아존중감 검사와 친구관계 검사를 사용하여 초등학교, 중학교, 고등학교 집단에 대해 각각 확인적 요인분석을 수행하여 결과를 비교하였다. 분석 결과 각 검사에 대한 연구모형에서 CTCM 모형과 CTCU 모형이 다른 모형에 비해 좋은 적합도 지수를 보였으며, 자아존중감 검사에서는 부정문항의 방법효과, 친구관계 검사에서는 긍정문항의 방법효과가 있는 것으로 판단하였다. 본 연구는 자아존중감 검사와 친구관계 검사를 분석하여, 긍정문항과 부정문항이 혼재된 검사의 요인구조 탐색 시 연구모형에서 반드시 방법효과를 고려해야함을 확인했다는 점에서 그 중요성이 있다. 또한 본 연구의 결과를 바탕으로 추후 방법효과와 관련하여 후속 연구에서 다뤄져야 할 몇 가지 사항을 추가로 제안하였다.

부정문항이 포함된 검사의 요인구조

홍세희(Sehee Hong),노언경(Unkyung No),정송(Song Jung) 한국교육평가학회 2011 교육평가연구 Vol.24 No.3

자기보고식 검사에서 부정문항이 포함된 경우, 요인구조가 불명확해지는 결과가 초래되고, 많은 연구자들이 부정문항이 포함된 검사의 요인구조와 그에 대한 해석에 대해 혼란을 겪고 있다. 문항형태로 인한 방법효과의 문제점을 알아보기 위해 본 연구는 한국청소년패널조사에 포함된 Rosenberg의 자아존중감 검사의 긍정문항, 부정문항을 이용하여 다양한 요인구조를 비교하였다. 분석결과, 긍정, 부정문항에 따라 요인을 별도로 설정하는 것보다는 부정문항의 방법효과를 통제한 상태에서 요인구조를 평가하는 것이 적합한 것으로 나타났다. 방법효과를 통제하는 방법으로 오차 공분산을 설정하는 방법과 방법요인을 도입하는 방법을 제시하고 연구목적에 따라 어떤 방법이 적절한지 제안하였다. 또한, 방법효과가 있는 경우 신뢰도값인 Cronbach alpha는 과대추정값이 될 수 있음을 설명하고 적절하게 신뢰도를 추정하는 방법을 제시하였다. Psychological scales containing negatively-worded items produce, in many cases, misleading factor structures due to method effects. To demonstrate how negatively-worded items distort factor structure, this study investigated factor structure of Rosenberg Self-Esteem Scale using Confirmatory Factor Analysis. Results show that controlling for method effects of negatively-worded items, factor structure can be more clearly defined. This study provides several suggestions about when method factor can be introduced and when correlated uniquenesses can be specified to deal with the issue of method effects. Finally, this study also demonstrates that Cronbach alpha can be overestimated for a test containing method effect and proposes that factor rho coefficient should be used instead.

A Sense Amplifier Scheme with Offset Cancellation for Giga-bit DRAM

Kang, Hee-Bok,Hong, Suk-Kyoung,Chang, Heon-Yong,Park, Hae-Chan,Park, Nam-Kyun,Sung, Man-Young,Ahn, Jin-Hong,Hong, Sung-Joo The Institute of Electronics and Information Engin 2007 Journal of semiconductor technology and science Vol.7 No.2

To improve low sense margin at low voltage, we propose a negatively driven sensing (NDS) scheme and to solve the problem of WL-to-BL short leakage fail, a variable bitline reference scheme with free-level precharged bitline (FLPB) scheme is adopted. The influence of the threshold voltage offset of NMOS and PMOS transistors in a latch type sense amplifier is very important factor these days. From evaluating the sense amplifier offset voltage distribution of NMOS and PMOS, it is well known that PMOS has larger distribution in threshold voltage variation than that of NMOS. The negatively-driven sensing (NDS) scheme enhances the NMOS amplifying ability. The offset voltage distribution is overcome by NMOS activation with NDS scheme first and PMOS activation followed by time delay. The sense amplifier takes a negative voltage during the sensing and amplifying period. The negative voltage of NDS scheme is about -0.3V to -0.6V. The performance of the NDS scheme for DRAM at the gigabit level has been verified through its realization on 1-Gb DDR2 DRAM chip.

저분자량 수용성 키토산의 항균 활성에 관한 연구

박윤경(Yoon Kyung Park),나재운(Jae Woon Nah) 한국고분자학회 2011 폴리머 Vol.35 No.5

항균제 대체제로 응용하기 위하여 다양한 저분자량 수용성 키토산(LMWSC; MW1, MW3, MW5, MW10)을 제조하였으며, 이들의 항균제 대체제 사용 가능여부와 그 작용 기작에 대하여 연구하였다. 먼저, 다양한 분자량 형태의 LMWSC를 이용하여 사람에게 유해한 각종 박테리아를 이용하여 항균효과를 확인하였고, 그 중 MW10의 항균효과가 가장 우수한 것으로 확인되었다. 그 반면 사람의 적혈구를 이용한 용혈활성 실험에서 독성을 나타내지 않았다. MW10의 항균 효과가 세균의 어느 부분에서 일어나는지 확인하기 위해 박테리아의 세포막 조건(PE/PG=7/3, w/w)으로 인공리포좀을 만들었고, 여기에 MW10을 처리한 결과 세균 막에서 항균효과를 나타냄을 추론할 수 있었다. Chitosan is a natural polymer derived from chitin that has been widely used as a dietary supplement and in a variety of pharmacological and biomedical applications. In addition, water-soluble chitosan has been used to enhance the stability of chitosan in water and reduce cytotoxic activity induced by acetic acid. In this study, the antibiotic activity and mechanism of low molecular weight water-soluble chitosan (LMWSC; MW1, MW3, MW5, and MW10) were examined in pathogenic bacteria cells and vesicles containing bacterial membrane lipids. MW10 displayed potent antibacterial activity against pathogenic bacteria strains and no cytotoxicity against mammalian cells. In addition, the degree of calcein leakage was examined as a function of lipid composition (PE/PG=7/3 w/w). The results of these experiments demonstrated that MW10 promoted leakage in negatively-charged membranes. Furthermore, confocal microscopy revealed that MW10 was located in the plasma membrane.

Causes responsible for the in vivo reduction of activity of paraoxonase 1, a detoxifying enzyme of anticholinesterase organophosphates

Sok, Dai-Eun 忠南大學校 生命科學硏究院 醫藥品開發硏究所 2006 藥學論文集 Vol.21 No.-

Paraoxonase 1(PON1), which is well known to hydrolyze organophosphates such as paraoxon and nerve agents, is widely distributed in blood, liver, heart, kidney as well as brain. Also, mRNA for PON1 was detected in a number of tissues apart from the liver, suggesting a possible role for this protein family. Initial investigation of PON1 focused on its ability to hydrolyze organophosphate compounds, playing a major role in the detoxification of these compounds. Recent interest in the enzyme has arisen from the observations that they possess antioxidant action against copper ion-catalyzed oxidation of lipids or proteins. Such an antioxidant action could contribute to further augment the benefit of paraoxonase1 in preventing against organophosphate poisoning, especially accompanied by oxidative stress. Therefore, it is important to maintain PON1 activity in vivo. Above all, it has been of a curiosity to find the causes responsible for the loss of PON1 activity, and provide the measures to prevent against the reduction of PON1 level. The mechanisms responsible for the in vivo inactivation of PON1 by oxidative conditions will be reviewed. In addition, the inhibition of PON1 activity by endogenous factors including negatively-charged lipids will be addressed. Further, the strategy to preserve the activity of paraoxonase 1, a detoxifier of anticholinesterase organophosphates, in vivo system will be discussed. Finally, there will be a discussion on the possible common function of two hydrolases, acetylcholinesterase and paraoxonase 1, in preventing oxidative stress.

On the strong law of large numbers for weighted sums of negatively superadditive dependent random variables

Aiting Shen 대한수학회 2016 대한수학회지 Vol.53 No.1

Let $\{X_n, n\geq1\}$ be a sequence of negatively superadditive dependent random variables. In the paper, we study the strong law of large numbers for general weighted sums $\frac{1}{g(n)}\sum_{i=1}^n\frac{X_i}{h(i)}$ of negatively superadditive dependent random variables with non-identical distribution. Some sufficient conditions for the strong law of large numbers are provided. As applications, the Kolmogorov strong law of large numbers and Marcinkiewicz-Zygmund strong law of large numbers for negatively superadditive dependent random variables are obtained. Our results generalize the corresponding ones for independent random variables and negatively associated random variables.

On the exponential inequalities for negatively dependent random variables

Academic Press 2011 Journal of mathematical analysis and applications Vol.381 No.2

A number of exponential inequalities for identically distributed negatively dependent and negatively associated random variables have been established by many authors. The proofs use the truncation technique together with the control of the bounded terms and unbounded terms. In this paper, we improve essentially the control of bounds for the unbounded terms and obtain exponential inequalities for negatively dependent random variables which include negatively associated random variables. Our results improve on the corresponding ones in the literature.

ON THE STRONG LAW OF LARGE NUMBERS FOR WEIGHTED SUMS OF NEGATIVELY SUPERADDITIVE DEPENDENT RANDOM VARIABLES

SHEN, AITING Korean Mathematical Society 2016 대한수학회지 Vol.53 No.1

Let {$X_n,n{\geq}1$} be a sequence of negatively superadditive dependent random variables. In the paper, we study the strong law of large numbers for general weighted sums ${\frac{1}{g(n)}}{\sum_{i=1}^{n}}{\frac{X_i}{h(i)}}$ of negatively superadditive dependent random variables with non-identical distribution. Some sufficient conditions for the strong law of large numbers are provided. As applications, the Kolmogorov strong law of large numbers and Marcinkiewicz-Zygmund strong law of large numbers for negatively superadditive dependent random variables are obtained. Our results generalize the corresponding ones for independent random variables and negatively associated random variables.

Positively and Negatively Charged Collagen Nanohydrogels: pH‐responsive Drug‐releasing Characteristics

김한샘,김성진,강지혜,신원상 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.4

Researchers are facing many challenges in developing a strategy for site‐specific delivery in the gastrointestinal tract that can maximize therapeutic response and reduce side effects. The objective of this article was to develop a site‐specific drug delivery system for the gastrointestinal tract using natural polymer collagen (CG). For this, two types of pH‐responsive CG nanohydrogels (negatively charged pH‐CGNH‐COOH and positively charged pH‐CGNH‐NH2) were prepared using negatively and positively functionalized carbon nanotubes, CNT‐COOH and CNT‐NH2, respectively. The pH‐CGNH‐COOH and pH‐CGNH‐NH2 nanohydrogel samples comprising negatively and positively charged fibrils (CG/CNT‐COOH and CG/CNT‐NH2) were physicochemically characterized by Fourier‐transform infrared spectrometry, Zeta sizer, thermogravimetric analysis, and field emission scanning electron microscopy. They also revealed the pH‐responsive release of bovine serum albumin at pH 9 and cytochrome C at pH 2. These results strongly indicate that these drug carriers can be useful for site‐specific delivery in the gastrointestinal tract.

ON THE COMPLETE CONVERGENCE FOR WEIGHTED SUMS OF NEGATIVELY SUPERADDITIVE DEPENDENT RANDOM VARIABLES

SEO, HYE-YOUNG,SHII, DA-LI,BAEK, JONG-IL The Korean Society for Computational and Applied M 2019 Journal of applied mathematics & informatics Vol.37 No.3

We are presented of several basic properties for negatively superadditive dependent(NSD) random variables. By using this concept we are obtained complete convergence for maximum partial sums of rowwise NSD random variables. These results obtained in this paper generalize a corresponding ones for independent random variables and negatively associated random variables.