• Proceedings of the Korean Society of Computer Information Conference
• /
• 2010.07a
• /
• pp.129-132
• /
• 2010

작금의 현대 사회 사람들은 바쁜 일상생활로 인해 짧아진 수면과 불면증 등의 각종 수면장애를 겪고 있으며, 여러 가지의 요소로 인하여 수면의 방해를 받게 되면, 여러 질병 및 생활 장애를 겪을 수 있어 수면의 중요성은 날로 주목받고 있다. 본 논문에서는 수면을 이루는 침실의 수면 환경 데이터를 수집하여 얻어진 조건 데이터들과 수면간의 관계를 분석하고 이를 바탕으로 시뮬레이션 모델을 추출하여 개개인에 따른 최적의 환경을 제공할 수 있다. 따라서 수면 과정에 따라 신체의 감각 및 자극에 대한 반응을 알고, 사람의 신체 상황에 따른 차이점 및 안정적인 패턴 및 조건을 정의하며 수면 패턴을 분석 및 솔루션 제공을 할 수 있다. 또한 차후에는 수면의 특정 상황만 아니라 식사, 출근, 등과 같은 유기적인 생활(유비쿼터스 환경)의 한 부분에도 상황에 따른 적절한 실내 환경 변화를 제공해주어서 좀 더 쾌적한 일상생활을 영위할 수 있도록 도움을 주게 되는 측면으로 확대 하려한다.

• 한국ITS학회:학술대회논문집
• /
• v.2007 no.10
• /
• pp.225-229
• /
• 2007

Recently, wireless sensor networks are deployed in various applications range from simple environment monitoring systems to complex systems, which generate large amount of information, like motion monitoring, military, and telematics systems. Although wireless sensor network nodes are operated with low-power 8bit processor to execute simple tasks like environment monitoring, the nodes in these complex systems have to execute more difficult tasks. Generally, MAC protocols for wireless sensor networks attempt to reduce the energy consumption using duty cycling mechanism which means the nodes periodically sleep and wake. However, in the duty cycling mechanism. a node should wait until the target node wakes and the sleep latency increases as the number of hops increases. This sleep latency can be serious problem in complex and sensitive systems which require high speed data transfer like military, wing of airplane, and telematics. In this paper, we propose a solution for reducing transmission latency through distributed duty cycling (DDC) in wireless sensor networks. The proposed algorithm is evaluated with real-deployment experiments using CC2420DBK and the experiment results show that the DDC algorithm reduces the transmission latency significantly and reduces also the energy consumption.

• Safety and Health at Work
• /
• v.6 no.2
• /
• pp.104-113
• /
• 2015

Background: Given the long hours on the road involving multiple and interacting work stressors (i.e., delivery pressures, irregular shifts, ergonomic hazards), commercial drivers face a plethora of health and safety risks. Researchers goal was to determine whether and to what extent long-haul trucker work schedules influence sleep duration and quality. Methods: Survey and biometric data collected from male long-haul truck drivers at a major truckstop in central North Carolina over a six month period. Results: Daily hours worked (mean = 11 hours, 55 minutes) and frequency of working over government-mandated daily HOS regulations (23.8% "frequently or always") were statistically significant predictors of sleep duration. Miles driven per week (mean = 2,812.61), irregular daily hours worked (63.8%), and frequency of working over the daily hour limit (23.8% "frequently or always") were statistically significant predictors of sleep quality. Conclusion: Implications of findings suggest a comprehensive review of the regulations and operational conditions for commercial motor vehicle drivers be undertaken.

• Journal of Korean Academic Society of Home Health Care Nursing
• /
• v.26 no.1
• /
• pp.27-35
• /
• 2019

Purpose: This study investigated sleep satisfaction and influencing factors in Korean adolescents with atopic dermatitis. Methods: Data were obtained from 4,570 subjects who completed the 2017 13th Korea Youth Risk Behavior Web-based Survey. For data analysis, descriptive statistics and multiple-sample logistic regression were used. Results: The results of this study were as follows. Gender, academic achievement, economic status, perceived stress, happiness, health status, and depression in the subjects showed a significant difference in terms of sleep satisfaction in atopic adolescents. Multiple-sample logistic regression analysis showed that male adolescents (odds ratio (OR)=0.48), academic achievement (low OR=0.67, middle OR=0.78), economic status (low OR=0.50, middle OR=0.64), lack of depression (OR=0.63), perceived stress (very OR=4.65, a little OR=2.25), perceived happiness (unhappy OR=1.99, moderate OR=1.22), perceived health status (unhealthy OR=2.17, ordinary OR=1.35), alcohol nondrinking (OR=0.75), and nonsmoking (OR=0.73) were not associated with sleep satisfaction. Conclusion: It is necessary to develop interventions that can relieve stress management and depression and develop positive emotions in atopic adolescents. In addition, there is a need to improve the environment to avoid health risks such as alcohol consumption and smoking and to minimize the effects of passive smoking.

• Journal of Environmental Health Sciences
• /
• v.40 no.5
• /
• pp.376-384
• /
• 2014

Objective: The purpose of this study is to compare the health status of residents who were exposed to sources of extremely low frequency electromagnetic fields (ELF-EMFs) in the living environment and those who were not exposed to such a source of ELF-EMFs through a survey designed to appraise the residents' health levels. Method: Aimed at 251 residents exposed to a source of ELF-EMFs and 278 residents not exposed to a source, the survey was conducted to investigate the health status of the residents on the basis of questionnaire SF-36. Result: The health status scores of residents exposed to ELF-EMFs turned out to be lower than those of their counterparts. In terms of self-reported symptoms related to health and sleep quality, residents exposed to ELF-EMFs were found to have a higher complaint rate of self-reported symptoms such as dizziness, depression, and fatigue. Regarding sleep disorders, residents exposed to ELF-EMFs appeared to have a slightly higher complaint rate of sleep disorders compared to non-exposed residents. Conclusion: If a region is to be exposed to a source of ELF-EMFs, a more proactive policy for reducing such exposure is advised. In addition, it is necessary to better understand problems of residents by emplacing an ELF-EMFs risk information delivery system and building an efficient communication system for voluntary participation during the construction phase.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.22 no.3
• /
• pp.244-256
• /
• 2012

Objectives: This study was conducted to assess the level of depression and its association with sociodemographic characteristics and health related characteristics, job-related characteristics, sleep quality, occupational stress among manufacturing male immigrant worker in Korea. Methods: Total number of subject were 287 workers employed in 19 manufacturing industry. A structured self-administered questionnaire was used to assess each responder's sociodemographic and health related characteristics, job-related characteristics, sleep quality (PSQI), Korean occupational stress (KOSS), Depression (CES-D). The job stress questionna ire was used according to KOSS-26 and depression symptoms were measured using CES-D, which was translated into Korean. We used multiple logistic regression analysis to assess the relationship between risk factors included job stress, sleep quality and depression. Results: The prevalence of depression in survey subjects was 63.9%and poor group (PSQI) (5 point and over at PSQI score)among all subjects were 83.28%. Adjusting for confounding factor, higher the occupational stress (KOSS), depression levels were significantly higher (${\beta}=0.5575$), worse quality of sleep, the more depressed the level was slightly high ${\beta}=0.118$) did not reach statistical significance. Conclusions: The prevalence of depressive symptoms among the study subjects was higher than that among the Korean workers. Especially, the level of depression was more influenced by occupational stress than quality of sleep. Therefore, the author recommend to prepare the effective strategy for reducing the depression and also reducing the occupational stress among immigrant male workers, and the author consider that it need to support the convenient working environment such as consultation for difficulty or health care among immigrant male workers.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.15 no.5
• /
• pp.215-225
• /
• 2020

Light detection and ranging (LiDAR) sensors detect the distance of the surrounding environment and objects. Conventional LiDAR sensors require a certain amount of a power because they detect objects by transmitting lasers at a regular interval depending on a constant resolution. The constant power consumption from operating multiple LiDAR sensors is detrimental to autonomous and electric vehicles using battery power. In this paper, we propose two algorithms that improve the inefficient power consumption during the constant operation of LiDAR sensors. LiDAR sensors with algorithms efficiently reduce the power consumption in two ways: (a) controlling the resolution to vary the laser transmission period (T_P) of a laser diode (LD) depending on the vehicle's speed and (b) reducing the static power consumption using a sleep mode depending on the surrounding environment. A proposed LiDAR sensor with a resolution control algorithm reduces the power consumption of the LD by 6.92% to 32.43% depending on the vehicle's speed, compared to the maximum number of laser transmissions (N_x·max). The sleep mode with a surrounding environment-sensing algorithm reduces the power consumption by 61.09%. The proposed LiDAR sensor has a risk factor for 4-cycles that does not detect objects in the sleep mode, but we consider it to be negligible because it immediately switches to an active mode when a change in surrounding conditions occurs. The proposed LiDAR sensor was tested on a commercial processor chip with the algorithm controlling the resolution according to the vehicle's speed and the surrounding environment.

• Proceedings of the KOSOMBE Conference
• /
• v.1996 no.05
• /
• pp.10-13
• /
• 1996

We have developed the digital polysomnograph system to enhance the manual sleep study. This system is composed of host PC and target board. The host computer is IBM-PC Pentium 133 MHz and the target board is PC31 (processor type: TMS320C31). These two Processors communicate with each other by dualport RAM. Target board acquire 16 channel sleep signals from the Polysomnographic system (GRASS model 78, USA) and digitize them. We used high resolution monitor$(1600{\times}1280)$ to simulate the paper-recording quality of polysomnographic signal. We also implemented the GUI based polysomnographic staging program on the windows environment. Clinicians can score the sleep stage, and edit and mark the event efficiently. Finally it can support making patient database.

• Journal of Information Processing Systems
• /
• v.2 no.1
• /
• pp.39-43
• /
• 2006

In this paper, we proposed TASL-MAC, a medium-access control (MAC) protocol for wireless sensor networks. In wireless sensor networks, sensor nodes are usually deployed in a special environment, are assigned with long-term work, and are supported by a limited battery. As such, reducing the energy consumption becomes the primary concern with regard to wireless sensor networks. At the same time, reducing the latency in multi-hop data transmission is also very important. In the existing research, sensor nodes are expected to be switched to the sleep mode in order to reduce energy consumption. However, the existing proposals tended to assign the sensors with a fixed Sleep/Listening schedule, which causes unnecessary idle listening problems and conspicuous transmission latency due to the diversity of the traffic-load in the network. TASL-MAC is designed to dynamically adjust the duty listening time based on traffic load. This protocol enables the node with a proper data transfer rate to satisfy the application's requirements. Meanwhile, it can lead to much greater power efficiency by prolonging the nodes' sleeping time when the traffic. We evaluate our implementation of TASL-MAC in NS-2. The evaluation result indicates that our proposal could explicitly reduce packet delivery latency, and that it could also significantly prolong the lifetime of the entire network when traffic is low.

• Journal of Digital Contents Society
• /
• v.19 no.3
• /
• pp.489-496
• /
• 2018

This article is to examine the influence of occupational stress, socio-psychological factors and quality of sleep on fatigue symptoms from firefighters in fire service. The correlation coefficients were obtained by a tool of Pearson analysis, and covariance structure analysis was performed on the factors affecting the level of fatigue symptoms. This result suggests that the level of firefighters' fatigue symptoms in fire service. has a causal effect with occupational stress, socio-psychological factors and quality of sleep. Therefore, it is necessary to improve the work environment and to increase organizational support to deal with firefighters' fatigue in fire service.