• 산업경영시스템학회지
• /
• 제37권1호
• /
• pp.26-32
• /
• 2014

Mental fatigue is inevitable in the workplace. Since mental fatigue can lead to decreased efficiency and critical accidents, it is important to manage mental fatigue from the viewpoint of accident prevention. An experiment was performed to evaluate mental fatigue using the formant frequency analysis of human voices. The experimental task was to mentally add or subtract two one-digit numbers. After completing the tasks with four different levels of mental fatigue, subjects were asked to read Korean vowels and their voices were recorded. Five vowel sounds of "아", "어", "오", "우", and "이" from the voice recorded were then used to extract formant 1 frequency. Results of separate ANOVAs showed significant main effects of mental fatigue on formant 1 frequencies of all five vowels concerned. However, post-hoc comparisons revealed that formant 1 frequencies of "아" and "어" were most sensitive to mental fatigue level employed in this experiment. Formant 1 frequencies of "아" and "어" significantly decrease as the mental fatigue accumulates. The formant frequency extracted from human voice would be potentially applicable for detecting mental fatigue induced during industrial tasks.

• 말소리와 음성과학
• /
• 제5권1호
• /
• pp.3-10
• /
• 2013

This study proposes a method to measure mental fatigue using speech technology, which has not been used in previous research and is easier than existing complex and difficult methods. It aims at establishing a relationship between the human voice and mental fatigue based on experiments to measure the influence of mental fatigue on the human voice. Two monotonous tasks of simple calculation such as finding the sum of three one digit numbers were used to measure the feeling of monotony and two sets of subjective questionnaires were used to measure mental fatigue. While thirty subjects perform the experiment, responses to the questionnaire and speech data were collected. Speech features related to speech source and the vocal tract filter were extracted from the speech data. According to the results, speech parameters deeply related to mental fatigue are a mean and standard deviation of fundamental frequency, jitter, and shimmer. This study shows that speech technology is a useful method for measuring mental fatigue.

• 한국직업건강간호학회지
• /
• 제20권2호
• /
• pp.143-152
• /
• 2011

Purpose: This study investigated to relationship of fatigue, health promotion behavior and mental health in automotive manufacturing workers. Methods: As a descriptive research design, the data were collected from 198 workers in a city. It was analyzed using the SPSS/WIN 12.0. Results: The level of fatigue was beyond moderate, health promotion behavior was low, mental health was slightly unhealthy. The fatigue was significantly correlated with health promotion behavior. The global fatigue, job satisfaction and drinking explained 22.3% of health promotion behavior. Conclusion: It is necessary for the automotive manufacturing workers and their companies to reduce level of fatigue and mental health and to increase level of health promotion behavior.

• 융합정보논문지
• /
• 제11권10호
• /
• pp.10-19
• /
• 2021

본 논문은 뇌파 측정 및 분석을 통해 정신적 피로를 반영하는 특징 파라미터를 도출하고자 하였다. 이를 위해 30분간 눈을 감은 편안한 안정 상태와 뺄셈연산을 암산으로 수행하는 작업을 통해 정신적 피로를 유도하였다. 5명의 피험자가 실험에 참가하였으며, 피험자들은 모두 대학 재학 중인 오른손잡이 남학생들이며 평균 나이는 25.5세이다. 정신적 피로를 반영하는 특징 파라미터 도출을 위해 실험 처음과 마지막에서 수집된 뇌파에 대해 스펙트럼분석을 수행하였다. 분석 결과, 정신적으로 피로할수록 후두엽 및 측두엽 위치에서 알파대역의 절대파워는 증가한 반면 상대파워는 감소하였다. 또한 안정 상태와 작업 상태간 파워 차이는 절대파워에 비해 상대파워가 크게 나타났다. 이 결과는 후두엽 및 측두엽 위치에서의 알파 상대파워가 정신적 피로를 반영하는 특징 파라미터임을 나타낸다. 본 연구 결과는 운전 중 피로 및 졸음 판단과 같은 정신적 피로 판별을 위한 자동화시스템 개발을 위한 특징 파라미터로 활용될 수 있다.

• 한국멀티미디어학회논문지
• /
• 제23권9호
• /
• pp.1147-1154
• /
• 2020

Nowadays, one of the most common diseases is chronic mental fatigue syndrome. This can be caused by many factors, such as busy life, heavy workload, high population density, and adverse technological impact. Most office workers and students who are sitting all day long while being exposed to this kind of environments are likely to be involved in the mental illness. Therefore, to prevent the illness, it has been highly required to design a device that enables mental fatigue to be monitored continuously without human intervention. This paper proposes a linear regression method to reliably estimating the level of human mental fatigue using wearable physiological sensors, with an estimation error of 0.852. Also, this paper presents an Android application that is able to check mental health conditions in daily life.

• 말소리와 음성과학
• /
• 제8권4호
• /
• pp.97-101
• /
• 2016

This paper presents a CART(Classification and Regression Tree)-based model to diagnose mental fatigue using speech technology. The parameters used in the model are the significant speech parameters highly correlated to the fatigue and questionnaire responses obtained before and after imposing the fatigue. It is shown from the experiments that the proposed model achieves classification accuracies of 96.67% and 98.33% using the speech parameters and questionnaire responses, respectively. This implies that the proposed model can be used as a tool to diagnose the mental fatigue, and that speech technology is useful to diagnose the fatigue.

• 말소리와 음성과학
• /
• 제6권2호
• /
• pp.3-8
• /
• 2014

This paper deals with how mental fatigue has an effect on human voice. For this a monotonous task to increase the feeling of the fatigue and a set of subjective questionnaire for rating the fatigue were designed. From the experiments the designed task was proven to be monotonous based on the results of the questionnaire responses. To investigate a statistical relationship between speech features extracted from the collected speech data and fatigue, the T test for two-related-samples was used. Statistical analysis shows that speech parameters deeply related to the fatigue are the first formant bandwidth, Jitter, H1-H2, cepstral peak prominence, and harmonics-to-noise ratio. According to the experimental results, it can be seen that voice is changed to be breathy as mental fatigue proceeds.

• 한국식품과학회지
• /
• 제6권3호
• /
• pp.158-162
• /
• 1974

The writer has undertaken a survey, against 467 urban university women students, of the fatigue due to their schoolwork and has intended to clarify the relationship between the fatigue and dietary. As a result, the following described conclusion was obtained: (1) The fatigue due to their schoolwork was found in an order of mental fatigue >physical fatigue> neuro-sensory fatigue among which their schoolwork was proved as a typical mental works. (2) It was found, in comparison of the health condition with the fatigue from schoolwork, that the frequencies of mental and neurosensory fatigue in which physical fatigue is excluded had a significant difference. (3) In an analysis of the fatigue rate in relation with the daily dietary, it was found that fatigue rate of the group which takes meat, egg, fish and milk every day showed a significantly lower rate over the group which takes these food occasionally.

• 감성과학
• /
• 제4권2호
• /
• pp.63-68
• /
• 2001

조명 색온도에 따른 작업자의 피로도를 평가하기 위하여 세 종류의 조명 색온도(2700 K, 4000 K, 6500 K)를 실험변수로 하여 모니터상에서 오류수정 작업이 수행되었다. 색온도의 변화에 따른 인체의 영향을 평가하기 위하여 먼저 주관평가와 작업수행도의 상관관계를 분석하였다. 시각피로·정신피로와 집중도에 관한 주관평가를 실시한 결과, 2700 K에서 시각피로 및 정신피로가 가장 적고 집중도가 높으며 작업수행도가 가장 좋았다. 6500 K에서 정신피로를 가장 많이 느끼고 집중도가 제일 낮았으나, 시각피로를 가장 많이 느낀 4000 K에서의 작업수행도가 가장 낮았다. 결과적으로 세 가지 색온도 조건 중 2700 K가 모니터상의 오류수정 작업에 가장 적합하다고 할 수 있다.

• Safety and Health at Work
• /
• 제13권2호
• /
• pp.148-154
• /
• 2022

Background: Bus driving is a mentally demanding activity that requires prolonged attention to ensure safety. The aim of the study was to assess mental fatigue caused by driving a public bus and to find a profile of workers at higher risk. Methods: We evaluated changes of critical flicker fusion (CFF) (index of central arousal) and heart rate variability (HRV) (index of autonomic balance) in a 6-hour driving shift on a real route, in 31 professional bus drivers, and we tested the influence of personal factors such as sleep quality, BMI, and age. Paired t-test was used to test differences of CFF and HRV between both initial and final phase of driving, while multiple linear regression tested the influence of personal variables on the indexes of mental fatigue. Results: Results showed that CFF significantly decreased after 6 hours of bus driving (41.91 Hz, sd 3.31 vs. 41.15 Hz, sd 3.15; p = 0.041), and heart rate significantly decreased in the final phase of driving, with respect to the initial phase (85 vs. 78 bpm, p = 0.027). Increasing age (beta = -0.729, p = 0.022), risk of obstructive sleep apnea syndrome (beta = -0.530, p = 0.04), and diurnal sleepiness (beta = -0.406, p = 0.017) showed a significant effect on influencing mental fatigue. Conclusion: Elderly drivers at higher risk of sleep disorders are more prone to mental fatigue, when exposed to driving activity. Monitoring indexes of central arousal and autonomic balance, coupled with the use of structured questionnaires can represent a useful strategy to detect profile of workers at higher risk of mental fatigue in such duty.