• 대한수학회보
• /
• 제61권3호
• /
• pp.867-873
• /
• 2024

A pseudo-Riemannian solvmanifold is a solvable Lie group endowed with a left invariant pseudo-Riemannian metric. In this short note, we investigate the nilpotency of the Ricci operator of pseudo-Riemannian solvmanifolds. We focus on a special class of solvable Lie groups whose Lie algebras can be expressed as a one-dimensional extension of a nilpotent Lie algebra ℝD⋉n, where D is a derivation of n whose restriction to the center of n has at least one real eigenvalue. The main result asserts that every solvable Lie group belonging to this special class admits a left invariant pseudo-Riemannian metric with nilpotent Ricci operator. As an application, we obtain a complete classification of three-dimensional solvable Lie groups which admit a left invariant pseudo-Riemannian metric with nilpotent Ricci operator.

• 한국광학회지
• /
• 제23권5호
• /
• pp.189-196
• /
• 2012

플로팅 광학계는 초점 맞춤 시, 2개 이상의 군이 움직이는 광학계를 의미한다. 카메라 광학계에서는 매크로 렌즈와 같이 배율 변화가 큰 광학계에 주로 채용된다. 플로팅 광학계도 가공 및 조립 오차로 인해 무한대단 및 매크로단의 초점위치가 촬상소자의 결상면과 일치하지 않는다. 그러므로 제조공정상에서 이러한 BWD(Back Working Distance) 차이를 최소화하는 초점 조정을 해야 한다. 본 논문에서는 플로팅 광학계의 각 군들의 이동량을 결정하기 위하여 초점 조정에 필요한 캠 회전각을 계산하고, 초점조정에 따른 플로팅 광학계의 최대 배율도 보정하는 수치해석 방법을 제안하였다. 그리고 이를 이용하여 대칭형 공차를 갖는 플로팅 광학계의 제조 오차를 고려한 초점 조정에 필요한 캠 회전각의 분포를 통계학적으로 계산하여 캠 회전각의 허용 범위를 결정하는 방법도 제안하였다.

• 인지과학
• /
• 제31권4호
• /
• pp.137-154
• /
• 2020

학습 상황에서 개인의 내적 특성은 다양한 방식으로 학습행동에 영향을 준다. 특히 '동기'는 학습자의 목표 설정하 및 전략 선택에 영향을 주는 핵심적인 요소이다. 본 연구는 학습자의 목표지향이 학습 시간 분배 방식에 어떠한 영향을 미치는가를 확인하였다. 참가자들의 목표지향 상태를 달리하기 위하여 관련 변인인 조절초점(regulatory focus)과 지능관점(theories of intelligence)을 측정 및 조작하여 집단을 구분하였다. 두 변인은 각각 접근-회피전략(조절초점에 따른 동기 성향)과 숙달-수행지향적 태도(지능관점에 따른 동기)를 유발하며 학습자의 목표지향(goal orientation) 형성에 영향을 주는 핵심적인 변인으로 알려져 왔다. 실험에서 조절초점은 성향검사점수를 기준으로 두 집단으로 구분하였으며, 조작을 통해 지능관점의 차이를 일시적으로 유발하여 두 변인 간의 상호작용을 확인하였다. 참가자들은 일련의 스페인어-한국어 단어 쌍을 학습한 후 재학습하고 싶은 항목을 선택하여 자유롭게 학습순서를 결정할 수 있었다. 단어 쌍은 어렵거나 쉬운 항목들로 구성되어 있었으며, 학습자들은 원한다면 같은 단어를 여러 번 학습할 수 있었다. 결과에서, 조절초점과 지능관점에 따라 학습 초반에 어려운 단어를 선택하는 비율의 상호작용 효과가 나타났다. 즉, 향상초점-증진조건의 참가자들은 향상초점-불변조건의 참가자들에 비해 학습 초반에 어려운 단어를 배치하는 비율이 높았으며, 예방초점인 학습자들은 지능관점의 영향을 받지 않았다. 이러한 결과는 학습자의 목표지향에 따라 학습 전략을 세우는 방식이 다를 수 있음을 보여준다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권11호
• /
• pp.5791-5797
• /
• 2012

Introduction: Return-to-work (RTW) can be a problematic occupational issue with detrimental impact on the quality of life of previously-employed breast cancer survivors. This study explored barriers and facilitators encountered during the RTW process in the area of cancer survivorship. Materials and Methods: Six focus groups were conducted using a semi-structured interview guide on 40 informants (employed multiethnic survivors). Survivors were stratified into three groups for successfully RTW, and another three groups of survivors who were unable to return to work. Each of the three groups was ethnically homogeneous. Thematic analysis using a constant comparative approach was aided by in vivo software. Results: Participants shared numerous barriers and facilitators which directly or interactively affect RTW. Key barriers were physical-psychological after-effects of treatment, fear of potential environment hazards, high physical job demand, intrusive negative thoughts and overprotective family. Key facilitators were social support, employer support, and regard for financial independence. Across ethnic groups, the main facilitators were financial-independence (for Chinese), and socialisation opportunity (for Malay). A key barrier was after-effects of treatment, expressed across all ethnic groups. Conclusions: Numerous barriers were identified in the non-RTW survivors. Health professionals and especially occupational therapists should be consulted to assist the increasing survivors by providing occupational rehabilitation to enhance RTW amongst employed survivors. Future research to identify prognostic factors can guide clinical efforts to restore cancer survivors to their desired level/type of occupational functioning for productivity and wellbeing.

• 대한간호
• /
• 제34권3호
• /
• pp.69-84
• /
• 1995

The purpose of this study was to identify caregivers of the elderly, the pattern of the caregivers' caring behaviors, and the cultural principles of patterns of caring behaviors practiced in a Korean minority community, Yanbian. To clarify these, an ethnographic approach was used. The fieldwork for this study was conducted from Aug. 24, 1993 to May 20, 1994. The informants were 16 natives, age 60 or more, who were members of a large family of three generations. The results of the study are as follows. The caregivers for the elderly were family, kinship and community groups. Family caregivers for the elderly were spouses, sons, daughters-in-law, grandchildren, sons of former wives, sons of former husbands, adopted sons. daughters and sons-in-law. The elderly had caregivers who were part of the kinship group. Three community groups provided care for the elderly. The three community groups were Dokbozo. a formal large organization for the elderly. the same age group as an informal small meeting for the elderly, and other community younger groups. The findings of this study indicated that family caregivers, especially spouses and sons, are the significant others of the elderly, and comminuty groups are better caring groups than kinship relatives. This study identified forty-three different kind of caring behaviors. They were divided into fifteen behavior patterns. These patterns integrated into five categories : soo-bal(¼?¹ß), protecting, respect, support, jung(?×). For physical comfort, soo-bal and protecting were conducted. For the comfort of mind, respect. support, and jung were conducted. The comfort of mind are better than physical comfort for the elderly. Cultural principles of caring behaviors were group membership, reciprocity, and harmony. But there was no hierarchy priciple. And these three principles provide best caring together at the same time. This study provides significant data for nursing research, theory and practice.

• 동서간호학연구지
• /
• 제25권1호
• /
• pp.17-25
• /
• 2019

Purpose: This study investigated the factors influencing sleep quality in adults according to age groups. The escriptive study was conducted in metropolitan areas of South Korea to control for possible sleep differences between adults living in rural areas and those living in cities. Participants were 450 adults between 19 and 65 years old. Methods: Self-administered questionnaires consisting of including the Korean Modified Sleep Leeds Evaluation Questionnaire, the International Physical Activity Questionnaire and the Perceived Stress Scale were used to assess the quality of adults' sleep. Results: Sleep quality was poor across the all age groups Stress and subjective health status were influencing factors of sleep quality among participants in their 20s; subjective health status and circadian rhythm (evening-type) were influencing factors of those in their 30s; subjective health status, alcohol consumption, and work days of less than 8 hours were influencing factors among participants in their 40s; and stress, circadian rhythm (evening-type), subjective health status, work days of over 11 hours, past smoking habit, and light physical activity were influencing factors of those aged 50 years and over. Conclusion: The quality of sleep was low across the all adult age groups in South Korea. Although the factors influencing quality of sleep differed by age groups, they in general indicate the need to focus on maintaining and controlling health status in sleep interventions.

• 한국의류학회지
• /
• 제36권3호
• /
• pp.282-296
• /
• 2012

This study identified the types of motives for reading consumer reviews of apparel products for online stores and classified shoppers into the groups based on motives. Data were collected from eleven Korean women by a focus group interview and from 313 females by an online survey. Respondents were in their 20s' and 30s' with significant experience reading consumer reviews of apparel products for online stores. The seven motives found by interviews were reduced to four types of motives by factor analysis: Right product choice and judgment of product value, risk reduction, saving time and money, and fun/killing time. The motive for the right product choice and judgment of product value was the highest and the motive for fun/killing time was the lowest. Consumers were classified into four groups based on motives: Utilitarian shoppers (25.8%), shopping-task oriented shoppers (36.8%), multiple-motive shoppers (19.7%), and moderate-motive shoppers (17.7%). There were significant differences among age groups and the amount of reading reviews posted on a product and the duration of reading reviews for online stores. In addition, managerial implications were developed.

• 한국IT서비스학회지
• /
• 제14권1호
• /
• pp.129-143
• /
• 2015

This study has two goals. The first goal is to investigate whether worked examples are effective in the ill-defined domain with on-line learning and the second goal is to find out which components (conceptual or procedural knowledge) of worked examples are effective factor at the given learning environment. We carried out three experiments in which Korean undergraduate or graduate students were working in three or four conditions of worked examples (CWE, PWE, CPWE, or the control group). While experiment 1 conducted in on-line learning environment did not find any effect and difference among groups and also any logical reason for those results, experiment 2 conducted in completely controlled laboratory setting with less knowledgeable students showed the clear difference among groups by the order CPWE, PWE, and CWE. Experiment 3 in which highly knowledgeable and motivated students were presented the same materials in more controlled on-line learning environment indicated the difference among groups by the order CWE, CPWE, and PWE. The results were discussed within the framework of cognitive load theory.

• 한국의상디자인학회지
• /
• 제19권2호
• /
• pp.145-157
• /
• 2017

This study aimed to investigate the relationship between values orientation and fashion image orientation with a focus on the new senior generation. The study conducted data analysis by using the SPSS 17.0 program for the final 397 copies excluding incomplete questionnaires. The results of this study are as follows. First, values orientation was drawn as the four factors of social orientation, dependent orientation, family-like orientation, and individual orientation. The fashion image orientation was compartmentalized as three factors: urban image, individual image, and feminine image. Second, social orientation had a significant effect on feminine image as shown in Photo 1, while only individual orientation exerted a significant influence on individual image (Photo 2). Social orientation and family-like orientation respectively exercised a significant influence on individual image and feminine image, and feminine image (Photo 3). Third, the four groups did not show a significant difference in the relationship with the sub-elements of fashion image orientation. It appeared that all four groups were felt as a complex image in which modern, feminine, and individual images were mixed. Fourth, the four groups showed a significant difference in the unusual, elegant, refined, youthful, feminine, and modern images among the factors of fashion image orientation.

• 복식문화연구
• /
• 제19권3호
• /
• pp.622-636
• /
• 2011

The purpose of this study was to assess the effects of self-image congruence on attitudes toward purchase intentions of children's clothing via the Behavioral Intention Model. The empirical study was conducted via on-line survey and data were collected from mothers with children aged 6 to 10 years. A total of 593 respondents answered the questionnaire and 574 usable data were statistically analyzed. SPSS 18.0 was used to conduct descriptive statistical analysis, factor analysis, reliability analysis, cluster analysis, Chi-square test, ANOVA, and multiple regressions. A K-means cluster analysis was conducted based on three dimensions brand images of children's wear. Respondents were divided into four groups: elegant image group, multiple image group, ordinary image group, and childlike image group. Characteristics of consumers and clothing evaluative criteria that mothers considered important differed significantly across groups. Moreover, based on these groups, each dimension of self-congruence had different effects on brand attitude. Brand attitude and subjective norms had different effects on purchase intentions. In conclusion, levels of self-congruence and factors influencing purchase intention varied according to brand images of children's wear.