• Human Ecology Research
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• 제58권2호
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• pp.255-266
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• 2020

This study observed and investigated the commute time of dual-earner couples from a family developmental perspective. It tested whether the household responsibility hypothesis was effective in explaining the gender gap in the commute time for these couples. I extracted 2,103 time diaries written by 1,266 matched couples from the 2014 Korean Time Use Survey data for this study. The sample was categorized by the age of the eldest child into four age groups of 0-6, 7-12, 13-18, and 19-29. Analytic results from ANOVA, Scheffé test, and OLS regression are as follows. First, husbands traveled longer hours to work than wives in all age groups, while the commute time of couples tended to increase along with the child' age. However, couples in the child group aged 7 to 12 had the shortest commute time. Second, domestic labor time of wives were negatively associated with the commute time, which appeared to support the household responsibility hypothesis. Third, in the child group aged 7 to 12, wives spent more time for work commute as their income increased; however, wives with traditional gender role attitudes had a shorter commute time in the child group aged 0 to 6. Forth, neither the wives' nor husbands' work characteristics were related to the wives' commute time; however, both wives' and husbands' work characteristics were related to the husbands' commute time. The findings suggest the possibility of spatial entrapment by working wives throughout the family life cycle due to household responsibilities, which provides implications for policy intervention in consideration of the gender gap in commute time for dual-earner couples.

• Safety and Health at Work
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• 제10권4호
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• pp.470-475
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• 2019

Background: There is a lack of statistical analysis investigating the relationship between sleep problems and commute time in Korea. We aimed to analyze the association between representative health symptoms, sleep disturbances, and commute time according to working hours in Korea. Methods: The 4th Korean Working Conditions Survey data were used for analysis, and unpaid family workers and workers who work fewer than three days in a week were excluded. Commute time, working hours, and sleep hours were assessed using self-reported questionnaires. Odds ratios (ORs) with 95% confidence intervals (CIs) for sleep problems were calculated using a multivariate logistic regression model with ≤10 min commute time as the reference group. Results: Among a total of 28,804 workers (men = 14,945, women = 13,859), 2.6% of men and 3.2% of women experienced sleep problems. In both sexes, long commute time (51-60 minutes and >60 minutes) showed an increased OR [men, 2.03 (CI = 1.32-3.13) and 2.05 (CI = 1.33-3.17); women, 1.58 (CI = 1.05-2.39) and 1.63 (CI = 1.06-2.50), respectively]. In stratification analysis of working hours, long commute time (51-60 and > 60 minutes) showed an increased OR in men working >40 hours/week [2.08 (CI = 1.16-3.71) and 1.92 (CI = 1.08-3.41), respectively]. Furthermore, long commute time (41-50, 51-60, and >60 minutes) showed an increased OR in women working >40 hours/week [2.40 (CI = 1.27-4.55), 2.28 (CI = 1.25-4.16), and 2.19 (CI = 1.17-4.16), respectively]. Moreover, commute time >60 minutes showed an increased OR in women working ≤40 hours/week [1.96 (CI = 1.06-3.62)]. Conclusion: This large cross-sectional study highlights that long commute time is related to sleep problems in both sexes. Shorter commute times and decreased working hours are needed to prevent sleep problems in workers.

• Annals of Occupational and Environmental Medicine
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• 제35권
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• pp.9.1-9.10
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• 2023

Background: Studies conducted so far on the link between commute time and mental health among Koreans remain insufficient. In this study, we attempted to identify the relationship between commute time and subjective mental health using the 6^th Korean Working Conditions Survey (KWCS). Methods: Self-reported commute time was divided into four groups: ≤ 30 (group 1), 30-60 (group 2), 60-120 (group 3), and > 120 minutes (group 4). Subjective depression was defined as a score of 50 points or less on the WHO-5 well-being index. Subjective anxiety and fatigue were defined as answering 'yes' to the questionnaire on whether they had experienced it over the past year. The analysis of variance, t-test, and χ² test was used to analyze the differences among the characteristics of the study participants according to commute time, depression, anxiety, and fatigue. Odds ratios (ORs) and 95% confidence intervals (CIs) for depression, anxiety, and fatigue according to commute time were calculated using multivariate logistic regression models adjusted for sex, age, monthly income, occupation, company size, weekly working hours, and shift work status. Results: Long commute times showed increased ORs and graded increasing trends for depression, anxiety, and fatigue. The ORs for depression increased significantly in group 2 (1.06 [1.01-1.11]), group 3 (1.23 [1.13-1.33]), and group 4 (1.31 [1.09-1.57]) compared to group 1 (reference). The ORs for anxiety increased significantly in group 2 (1.17 [1.06-1.29]), group 3 (1.43 [1.23-1.65]) and group 4 (1.89 [1.42-2.53]). The ORs for fatigue increased significantly in group 2 (1.09 [1.04-1.15]), group 3 (1.32 [1.21-1.43]), and group 4 (1.51 [1.25-1.82]). Conclusions: This study highlights that the risk of depression, anxiety, and fatigue increases with commute time.

• 전자공학회논문지
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• 제52권2호
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• pp.162-170
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• 2015

컴뮤트 타임 임베딩을 구현하려면 그래프 라플라시안 행렬의 고유값과 고유벡터를 구하여야 하는데, $o(n^3)$의 계산량이 요구되어 대용량 데이터에는 적용하기 어려운 문제가 있다. 이를 줄이기 위하여 표본화 과정을 통하여 크기가 줄어든 그래프 라플라시안 행렬에서 구한 다음, 원래의 고유값과 고유벡터를 근사화시키는 Nystr${\ddot{o}}$m 기법을 주로 채택한다. 이 과정에서 많은 오차가 발생하는데, 이를 개선하기 위하여 본 논문에서는 그래프 라플라시안 대신에 가중치 행렬을 표본화하고 이로부터 구한 고유값과 고유벡터를 그래프 라플라시안의 고유값과 고유벡터로 변환하는 기법을 이용하여 대용량 데이터로 구성된 스펙트럴 그래프를 근사적으로 컴뮤트 타임 임베딩하는 기법을 제안한다. 하지만, 이 방식도 스펙트럼 분해를 계산하여야 하므로 데이터의 크기가 증가하면 적용하기 어려운 문제가 발생한다. 이의 대안으로, 스펙트럼 분해를 계산하지 않고도 데이터 집합의 크기에 영향을 받지 않으면서 컴뮤트 타임을 근사적으로 계산하는 방식을 구현하고 이들의 특성을 실험적으로 분석한다.

• 전자공학회논문지
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• 제51권2호
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• pp.148-155
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• 2014

본 논문에서는 파형 신호에서 패치를 추출하고 이를 패치 그래프로 구성한 다음, 이로부터 대표적인 다양체 임베딩 방식인 컴뮤트 타임 임베딩 기법을 구현하고, 이의 특성을 분석한다. 특히 음성 신호나 악기 음 등, 시간에 따라 스펙트럼이 가변적인 신호를 임베딩하면 스펙트럼의 변화에도 불구하고 그 신호 고유의 기하 구조를 생섬함을 실험으로 확인한다. 다양체 임베딩은 비선형 공간에 놓여 있는 고차원 데이터를 저차원 공간으로의 효율적인 맵을 가능하게 하지만 그래프 구성에 이용된 데이터에 대한 정보만 알 수 있고 그렇지 않은 데이터(out-of-sample data)에 대해서는 정보를 얻기 어렵다. 따라서 다양체 임베딩은 데이터 클러스터링에 적절히 적용 가능하지만, 훈련 과정을 통해 얻은 정보를 기초로 유추 기능이 요구되는 인식 등에는 응용하기 어려운 제약이 따른다. 이를 해결하기 위하여 본 논문에서는 다양체 임베딩이 인식 분야에도 적용 가능하도록 새로운 알고리즘을 제안하고 악기 음 분류 실험을 통하여 그 특성을 분석한다.

• 한국멀티미디어학회논문지
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• 제17권1호
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• pp.34-42
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• 2014

본 논문에서는 파형 신호와 이미지 등에서 패치를 추출하고 이를 패치 그래프로 구성한 다음, 이로부터 각 패치 간의 컴뮤트 타임을 구하여 이에 기반한 임베딩 기법을 구현하고, 가장 널리 이용되는 PCA(principal component analysis) 임베딩 결과와 비교 분석한다. 임베딩에서 차원을 줄일 경우 원 임베딩과 축소된 차원의 임베딩 간에는 오차가 크지 않도록 차원을 결정하는 것이 일반적이다. 하지만 본 논문에서 구현한 임베딩 방식은 삼차원 이하로 줄여 오차가 80~90%를 상회하여도 축소된 차원의 임베딩 공간에서 각 신호 고유의 기하 구조를 생성하므로 패턴 분류나 기계 학습 등의 응용 목적에 활용 가능함을 실험으로 확인한다.

• 한국환경보건학회지
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• 제50권2호
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• pp.157-167
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• 2024

Background: Several previous studies have shown that commuting is a source of stress for undergraduate students. However, few studies have investigated the effect of commuting on academic stress among undergraduate students, and there has been little awareness of the environmental impact of commuting. Objectives: To evaluate the associations between commute type and/or time and academic stress among undergraduate students in South Korea, focusing on environmental sustainability. Methods: We conducted an online survey and obtained information on commute types, commute times, and academic stress from 510 undergraduate students aged ≥19 years. Academic stress was comprised of five sub-categories of stress, and total academic stress ranged from 5 to 25 points. Multiple linear regression analysis was used to analyze the associations between commute type and commute time and academic stress. Furthermore, the students were grouped into 21 categories based on their transportation mode for commuting. CO₂ emission factors per each commuting category were calculated using the transportation type's CO₂ emission data from previous studies. Spearman's correlation analysis was used to confirm the correlation between CO₂ emission factors and total academic stress. Results: Students using home-to-school transportation without transfers (vs. walking) showed a significantly higher total academic stress of 2.19 points (95% CI: 0.58, 3.80). In contrast, students using school-to-home transportation without transfers (vs. walking) showed a significantly lower total academic stress of 1.96 points (95% CI: -3.55, -0.38). Moreover, students using transportation with lower CO₂ emission factors had lower academic stress scores (home-to-school: correlation coefficient = 0.507, p<0.001; school-to-home: correlation coefficient = 0.491, p<0.001). Conclusions: Our findings suggest that both commute type and time are significantly associated with academic stress among South Korean undergraduate students. When students select environmentally-friendly transportation, they may not only improve their mental health but also improve climate resilience.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.146-154
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• 2016

This paper presents methods to analyze the topological structures of the spaces composed of patches extracted from waveform signals, which can be applied to the classification of signals. Commute time embedding is performed to transform the patch sets into the corresponding geometries, which has the properties that the embedding geometries of periodic or quasi-periodic waveforms are represented as closed curves on the low dimensional Euclidean space, while those of aperiodic signals have the shape of open curves. Persistent homology is employed to determine the topological invariants of the simplicial complexes constructed by randomly sampling the commute time embedding of the waveforms, which can be used to discriminate between the groups of waveforms topologically.

• 한국주거학회논문집
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• 제23권5호
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• pp.31-39
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• 2012

This study has analyzed the effect of the housing affordability improvement of the residents in the metropolitan areas, applying Transit Supportive Home Loan (TSHL) which extends the loan amount according to the transportation cost saving based on Location Efficiency Mortgage (LEM) System in the USA. The previous studies focused on introducing LEM system to Korea, whereas this study has analyzed TSHL effect for the first time, taking into account the situation in Korea. For analysis, The Transportation Savings (TS) is calculated and Housing Affordability Index (HAI) is drawn by applying increased TS and DTI (Debt to Income), so the improvements of housing purchasing ability is examined by HAI's improvement. As a result, transit commute 1 (having own car) and transit commute 2 (without having own cars) respectively produce the TS of monthly average 36 thousand won and 110 thousand won in comparison with car using commute. Each additional loan (TSHL) amounts to 16.57 million won and 54.07 million won. As the distance is farther and the house price cheaper, the improvement of HAI is more outstanding. City hall area showed the highest improvements of HAI by 9.3% (transit commute 1) and 21.9% (transit commute 2) increase, in comparison with car using commute.

• 한국인터넷방송통신학회논문지
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• 제16권1호
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• pp.291-299
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• 2016

본 논문에서는 임의의 주기적인 현상이나 특성은 위상구조와 밀접한 관련이 있음을 추론하고 이를 실험적으로 확인한다. 실험대상으로 주기적 특성이 있는 다양한 악기음을 선택하여 이를 유클리드 공간에 임베딩하고 이로부터 호몰로지 군을 계산하여 위상특성을 분석한다. 이를 위하여, 파형신호에서 추출한 패치모음을 패치 그래프로 구성한 다음, 대표적인 다양체 학습 방식인 통근시간 임베딩 기법을 이용하여 기하구조로 변환한다. 스펙트럼이 시간에 따라 가변적인 파형신호를 통근시간 임베딩할 때, 그에 따라 생성되는 기하구조는 변화하지만 그 신호 고유의 내재된 위상구조는 거의 변하지 않는다. 본 논문에서는 임베딩 데이터의 일부를 표본화하여 단순 복합체를 구성한 다음 이로부터 호몰로지를 계산하여 임베딩 기하구조의 위상특성을 분석하고, 이의 활용방안을 논의한다.