• Child Health Nursing Research
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• v.18 no.2
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• pp.85-94
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• 2012

Purpose: Instead of a chaotic non circadian environmental approach, continuing regular day-night rhythm in neonatal nurseries may benefit the development of preterm infants. The purpose of this study was to define the effects of cycled lighting on circadian rhythms of premature infants. Methods: The experimental group included 15 preterm infants, and the control group, 15 premature infants in the NICU of a general hospital in Seoul. All infants were between 32 and 37 weeks' postconceptional age. The experimental group infants were provided with cycled lighting before discharge. The incubator or bassinet cover of the experimental group was off between 7 AM and 7 PM, and was covered between 7 PM and 7 AM. Results: There were significant differences in the NNNS score ($p$=.039), and some significant differences in the sleep-activity pattern between the experimental group and the control group, but distinct differences in sleep-activity patterns between the two groups could not be defined. Conclusion: The results of this study suggest that cycled lighting can be helpful in the neurobehavioral development of preterm infants. By modifying the NICU environment to provide a more developmentally supportive milieu, nursing professionals can better meet the infants' physiologic and neurobehavioral needs.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.248-254
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• 2009

The aim of this study is to optimize the light source combination which can maximize the capability of the illuminance and color temperature of circadian lighting apparatus. To achieve this goal, the circadian lighting apparatus was consisted of two different types of fluorescent lamps having different color temperature of 2000K and 8000K, respectively, and the capability of the illuminance and color temperature of circadian lighting apparatus was evaluated by optical simulation as the number of the respective lamps were varied. Considering the Kruithof's curve and exceptional cases, the ranges of illuminance and color temperature for the living activities were reclassified in 4 groups - gathering, studying, relaxing and sleeping - so that the target range of illuminance and color temperature of lighting apparatus was settled. As a result, in the case of adopting two fixtures in which four 2000K lamps and five 8000K lamps were consisted, respectively to one fixture, the highest illuminance was expected at 4000K and over 500lx of illuminance was calculated between 3000K and 6000K. Through the optimized combination of light sources, the range of illuminance and color temperature were calculated as $44{\sim}750lx$ and $2500{\sim}6500K$, respectively.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.35-45
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• 2016

Melatonin hormone involved in human's circadian rhythm adjustment sensitively responds to light's specific short wavelength ratio. A shift worker's circadian rhythm disturbance and sleep disorder are caused by the existing lighting conditions, whose short wavelength ratio is fixed. The life pattern of a shift worker changes irregularly because of irregular working hours and the same lighting environment; thus, his/her concentration is reduced. For such a reason, negative effects ensue to the detriment of healthy everyday life, including a high risk of accidents or having unsound sleep after leaving work. A smartphone-based wavelength control LED lighting system that targets shift workers and that can easily measure and control lighting suitable for wake-sleep cycle, according to working hours and closing hours, is proposed in this paper. First, after the light characteristics of LED lighting that changes depending on light control ratio are measured through the color sensor installed on the smartphone and the externally-linked Mini-Spectrometer, they are stored in the database. Based on the stored optical characteristics data, the measurement module and light control module are implemented. Lighting is offered using a control ratio having the maximum rate of short wavelength in consideration of the target illuminance, classified according to work type by identifying working hours as time when waking is required for shift workers. After a shift work leaves work, the amount of lighting is varied, using a control ratio having a minimum short wavelength rate so that a shift worker can enter the sleep state naturally.

• Journal of Korea Multimedia Society
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• v.24 no.1
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• pp.30-39
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• 2021

Research in the field of health lighting has continued to advance to reproduce the color temperature of natural light which periodically changes. However, most of this research could only reproduce a uniform circadian color temperature of natural light, therefore failing to realize the characteristics of the circadian cycle of color temperature difference by latitude and longitude. To reproduce the color temperature of natural light on which the characteristics of a region are reflected, the collection technology of real-time characteristics of natural light is needed. If the color temperatures which are not within a periodical pattern due to climate changes, etc., are measured, it will be difficult to judge the occurrence (presence) of the anomalies and to reproduce the circadian cycle of the color temperature of natural light. Therefore, this study proposes an algorithm for judging the anomalies in real time based on the sliding window to reproduce the color temperature of natural light. First, the natural light characteristics DB collected through the on-site measurement were analyzed, the differential values at a one-minute interval were calculated and examined, and then representative color temperature circadian patterns by solar terms were drawn. The anomalies were then detected by the application of the sliding window that calculated the deviation of the color temperature for the measured color temperature data set, which was collected through RGB sensors, while moving along the time sequence. In addition, the presence of anomalies was verified through the comparison study between the detection results and the representative circadian cycle of the color temperature by solar term. The judgment method for the anomalies from the measured color temperature of natural light was proposed for the first time, confirming that the proposed method was capable of detecting the anomalies with an average accuracy of 94.6%.

• Journal of Digital Convergence
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• v.11 no.4
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• pp.229-234
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• 2013

The purpose of this study is to develop a lighting apparatus of the illuminance and color temperature to maximize the ability of the optimal combination of light sources that can be controlled efficiently control device. Finding people comfortable feeling for indoor lighting that can be used in a variety of color temperature illumination area by combining light sensitivity can be realized. Lighting apparatus for fluorescent lamps with different color temperature of 2000K and 8000K, and by varying the quantity of each of the fluorescent lamps, the illuminance of lighting equipment and color temperature through optical simulations were evaluated. By infrared remote control receiver, divided into 5 types of relaxation, conversation, meeting, hospitality, arts and the lighting environment you want to transfer the PC0 ~ PC4 through the parallel port on the mode selected by the user at the receiving end the DC voltage output. EEFL inverter input DC voltage and the DC input voltage, depending on the level of EEFL dimming value (illuminance and color temperature) lighting environment you want to create change while using a PIR sensor EEFL automatically turn off if people do not have was developed so that the power consumption so you can save.

• Journal of Life Science
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• v.23 no.8
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• pp.1064-1072
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• 2013

Circadian rhythm is controlled by hormonal oscillations governing the physiology of all living organisms. In mammals, the main function of the pineal gland is to transform the circadian rhythm generated in the hypothalamic suprachiasmatic nucleus into rhythmic signals of circulating melatonin characterized by a largely nocturnal increase that closely reflects the duration of night time. The pineal gland has lost direct photosensitivity, but responds to light via multi-synaptic pathways that include a subset of retinal ganglion cells. Rhythmic control is achieved through a tight coupling between environmental lighting and arylalkylamine-N-acetyltransferase (AANAT) expression, which is the rhythm-controlling enzyme in melatonin synthesis. Previous studies on the nocturnal expression of AANAT protein have described transcriptional, post-transcriptional, and post-translational regulatory mechanisms. Molecular mechanisms for dependent AANAT expression provide novel aspects for melatonin's circadian rhythmicity. Extensive animal research has linked pineal melatonin for the expression of seasonal rhythmicity in many mammalian species to the modulation of circadian rhythms and to sleep regulation. It has value in treating various circadian rhythm disorders, such as jet lag or shift-work sleep disorders. Melatonin, also, in a broad range of effects with a significant regulation influences many of the body's physiological functions. In addition, this hormone is known to influence reproductive, cardiovascular, and immunological regulation as well as psychiatric disorders.

• Journal of Navigation and Port Research
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• v.34 no.10
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• pp.763-768
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• 2010

Today the light of mankind since the dawn of mankind and that they were living "lives" on the huge influence across space is a dynamic energy. Because of this, when all human beings with the light and you can feel more comfortable with a stable mind to the beauty and the pursuit of happiness is to have instincts. In this paper, a fuzzy control system using a combination of external environmental factors, respectively, the conversion of quantitative uncertainty information into the LED lighting is designed to express algorithms, available in indoor circadian control circuit was designed and fabricated LED. Factor in the external environment temperature, humidity, and light intensity values to the controller through the sensor to accept these values and the optimal values for lighting the fuzzy control algorithm is converted into human emotion to feel comfortable to express through the dimming control LED lighting.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.444-448
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• 1989

The division and circadian DNA-synthesis rtythm are studied in chick liver immediately after hatching. The vision function is tested by the mitotic and the $^3H-thymidine$ labelling index The DNA synthesis exhibited a cyclic variation of 12 hours immediately after hatching. The rhythmic changes of DNA synthesis was maintained in the liver of meal-fed chickens, but the DNA synthetic activities decreased gradually in the starved chicken liver. From this time, the rhythm of DNA synthesis was greatly afffected by lighting schedule, all these DNA synthesis of chicken liver was accompained by mitosis.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.62-66
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• 2000

This study investigated the effects of certain specific wavelengths of lighting on the autonomic nervous system (ANS) using the heart rate variability (HRV) as an index. Six subjects with normal color vision participated n this study between 15:00 and 17:00 hr to neutralize any visual differences arising from circadian rhythm. The environmental conditions of the laboratory were maintained in complete darkness and the temperature was equilibrated at 24$\Box$ with a relative humidity of 60%. Subjects were only subjected to light stimulation when the pupil of dyes attained a minimum size of 2 mm by projecting illumination equalized with the same spectral radiance of 500-700 nm with 50-nm internal radiance. HRV was calculated from electrocardiogram (ECG) with systematic respiratory control at 0.35 Hz. The results suggest that illumination with certain wavelengths may induce ANS activation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.7-17
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• 2015

Changes in melatonin concentration levels by differences in CCT of white LED light focused on Spectral Power Distribution (SPD) differences compared to the same CCT of conventional fluorescent light were analyzed. For this, melatonin concentration levels in saliva samples were taken over four different experiments at seven-day intervals. In 71.4% of participants, it was confirmed that melatonin concentration is suppressed by exposure to light, and a slight difference was observed by different CCTs. In addition, Experiment II with a high CCT was relatively high in terms of the melatonin suppression rate compared to Experiment III. A key finding was the possibility that different SPDs under a particular CCT of white LED light compared to the same CCT of conventional fluorescent light could have the same effect on the melatonin suppression.