• Journal of Sensor Science and Technology
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• v.20 no.6
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• pp.382-387
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• 2011

Whether a person is feeling sleepy or reasonably awake is important safety information in many areas, such as humans operating in traffic or in heavy industry. The changes of body signals have been mostly researched by looking at electroencephalogram(EEG) signals but more and more other medical signals are being examined. In our study, an electrocardiogram(ECG) signal is measured at a sampling rate of 100 Hz and used to try to distinguish the possible differences in signal between the two states: awake and drowsy. Practical tests are conducted using a wireless sensor node connected to a wearable ECG sensor, and an ECG signal is transmitted wirelessly to a base station connected to a server PC. Through the QRS complex in the ECG analysis it is possible to obtain much information that is helpful for diagnosing different types of cardiovascular disease. A program is made with MATLAB for digital signal filtering and graphing as well as recognizing the parts of the QRS complex within the signal. Drowsiness detection is performed by evaluating the R peaks, R-R interval, interval between R and S peaks and the duration of the QRS complex..

• Journal of The Korean Dental Society of Anesthesiology
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• v.8 no.2
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• pp.118-121
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• 2008

Background: This retrospective study aims to describe the airway management and to search predictive parameter for difficult intubation in 700 patients undergoing oromaxillary surgery. Methods: The medical records of 700 patients undergone oromaxillary surgery were reviewed for airway management during perioperative period. The cases of difficult intubation were selected and those radiologic findings were reviewed. The mandibular depth (MD), mandibular length (ML), thyromental distance (TMD) were measured. Results: In 41 cases difficult intubation were recorded in anesthetic record. The grade of Cormack and Lehane was III in 36 patients and IV in 5 cases. The MD of difficult intubation cases was $4.2{\pm}3.2\;cm$. The ML of difficult intubation cases was $10.1{\pm}3.8\;cm$. The TMD of difficult intubation cases was $5.9{\pm}4.3\;cm$. Under the fiberoptic guided awake intubation was undertaken in 75 patient. In none of the cases was failed nasotracheal intubation. Conclusions: The patients undergoing oromaxillar surgery have a potentially difficult airway but, if managed properly during perioperative preiod, morbidity and mortality can be reduced or avoided. The radiologic findings were poor predict for difficult intubation. The fiberoptic guided awake intubation is a safe alternative to direct laryngoscopic intubation.

• Child Health Nursing Research
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• v.13 no.2
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• pp.147-156
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• 2007

Purpose: The purpose of this study was to investigate the sleep/activity patterns of premature babies. Method: The subjects were 55 premature babies who were hospitalized in the Neonatal Intensive Care Unit (NICU) of one University Hospital in Daejeon from September 1, 2004 to March 31, 2006. The sleep/activity patterns of the premature babies were observed for 24 hours a day for 7 days. The observations were made and recorded by the researcher and 5 trained research assistants using NCASA records developed by Barnard et al. (1979). For statistical analysis, frequency, average, t-test, and Pearson correlation coefficients were used. Results: The infants slept more and had less awake periods during daytime than full-term infants. As the hospital stay of the premature babies increased, the amount of daytime sleep and total daily sleep decreased, and the amount of daytime awake periods increased. Conclusions: The findings suggest that the level of physical and physiological maturity of premature babies is one of the major variables that affect their sleep/activity patterns. Furthermore, the findings of this study will provide information about the sleep/activity patterns of premature babies, and present baseline data to develop the nursing intervention programs which support optimum development for the premature babies.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.360-365
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• 2010

In this paper, we present a distributed algorithm for detecting dynamic event regions in wireless sensor network with the consideration on energy saving. Our model is that the sensing field is monitored by a large number of randomly distributed sensors with low-power battery and limited functionality, and that the event region is dynamic with motion or changing the shape. At any time that the event happens, we need some sensors awake to detect it and to wake up its k-hop neighbors to detect further events. Scheduling for the network to save the total power-cost or to maximize the monitoring time has been studied extensively. Our scheme is that some predetermined sensors, called critical sensors are awake all the time and when the event is detected by a critical sensor the sensor broadcasts to the neighbors to check their sensing area. Then the neighbors check their area and decide whether they wake up or remain in sleeping mode with certain criteria. Our algorithm uses only 2 bit of information in communication between sensors, thus the total communication cost is low, and the speed of detecting all event region is high. We adapt two kinds of measure for the wake-up decision. With suitable threshold values, our algorithm can be applied for many applications and for the trade-off between energy saving and the efficiency of event detection.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.493-493
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• 2000

Multi-valued decision making for transitional stochastic events was newly derived based on conditional probability of database. The two values (on-off) decision making method without transition had been proposed by one of the author in a previous work for a purpose of realizing human on-off decision making. The current method is an extension of the previous on-off decision making. By combining the conditional probability and the transitional probability, the closed form of the algorithm for the multi-valued transitional decision making was derived. The proposed multi-valued decision making was successfully applied to the determination of the five levels of the vigilance of a subject during the EEG recording; awake stage, drowsy stage and sleeping stages (stage 1, stage 2/3, REM (rapid eye movement)). The method for determining the vigilance level can be directly usable for the two purposes; selection of awake EEG segments for automatic EEG interpretation, and determination of sleep stages through sleep EEG. The proposed multi-valued decision making with a mathematical background of the probability can be applicable widely, in industries and in medical fields for purposes of the multi-valued decision making.

• Journal of Internet Computing and Services
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• v.9 no.2
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• pp.43-50
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• 2008

In IEEE 802.11b wireless LAN, stations keep synchronization by receiving beacons being periodically sent by the AP (access point) when they run in low power mode. Beacon transmission is delayed if wireless channel is busy at a scheduled TBTT (target beacon transmission time), and stations must be awake until they receive the delayed beacon. In this paper, we propose a scheme that stations get their transmission delayed if they have little time for successful data transmission by the next TBTT. Beacon transmission without delay is guaranteed at every TBTT with this method so that the awake time of low power stations to receive beacon can be reduced. The proposed method is simulated and its characteristics ore described with the analysis of the results. The measured results in terms of beacon delay show some enhancement in energy consumption.

• Journal of The Korean Dental Society of Anesthesiology
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• v.10 no.2
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• pp.190-196
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• 2010

Difficult airway management including difficult intubation, difficult ventilation and difficult mask ventilation is a life threatening issue during anesthesia care. A 23-year-old woman with Treacher Collins syndrome was scheduled for distraction osteogenesis. She had hypoplasia of mandible and malar bone, bilateral deformities of auricles with partial deafness and antimongoloid slant of the palpebral fissures. A 56-year-old woman with mandibular hypoplasia due to childhood trauma was scheduled for distraction osteogenesis. She had a history of difficult intubation. We anticipated a difficult intubation and ventilation. Fiberoptic bronchoscopic guided awake intubation was selected for anesthesia induction. After intravenous injection of midazolam and remifentanil, 10% lidocaine pump spray on the pharyngolarynx with a direct laryngoscope and on the nasal canal. However fiberoptic bronchoscopic guided awake intubation was failed due to severe gag reflex. After intravenous injection of propofol and remifentanil using the target controlled infusion (TCI), mask ventilation was easily performed and, after intravenous injection of vecuronium, fiberoptic bronchoscopic guided intubation was easily performed using a wire reinforced endotracheal tube. The operation was completed successfully without any adverse events.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.91-96
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• 2019

There are so many low power MAC protocols for wireless sensor network. IEEE802.15.4 among them has disadvantage of a large power consumption for synchronization. To save power consumption it use the superframe operation alternating sleep mode and awake mode. But latency is longer result from superframe operation. Typical asynchronous B-MAC can have shorter latency according to check interval. But transmitter consumes more power because of long preamble. And receiver is suffering from overhearing. In this paper, we propose the adaptive check interval scheme of B-MAC for enhancing the power consumption and delay latency performance. Its power consumption is evaluated by comparing the proposed scheme with a typical IEEE802.15.4.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2218-2229
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• 2015

Recently Wi-Fi Alliance defined Wi-Fi direct, which can communicate through a direct connection between the mobile device anytime, anywhere. In Wi-Fi direct, all devices are categorized by group of owner (GO) and client. Since portability is emphasized in Wi-Fi direct devices, it is essential to control the energy consumption of a device very efficiently. In order to avoid unnecessary power consumed by GO, Wi-Fi direct standard defines two power management schemes: Opportunistic power saving scheme and Notice Of Absence (NOA) scheme. But, these two schemes do not consider the traffic pattern, so we cannot expect high energy efficiency. In this paper, we suggest an algorithm to enhance the energy efficiency of Wi-Fi direct power saving, considering the characteristics of multimedia video traffic. Proposed algorithm utilizes the statistical distribution for the size of video frames and adjusts the length of awake interval dynamically. Also, considering the inter-dependency among video frames, the proposed algorithm assigns priorities to video frames and ensures that a video frame with high priority is transmitted with higher probability than other frames with low priority. Simulation results shows that the proposed method outperforms the traditional NOA in terms with average delay and energy efficiency.

• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.107-118
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• 2007

Background : It is well known that non-rapid eye movement(NREM) sleep activates the occurrence of interictal epileptiform discharges(IED) in many epileptic syndromes. We performed this study to assess the effect of NREM sleep on IED in epileptic patients with organic brain lesions. Materials and Methods : We analyzed awake and sleep electroencephalopathy(EEG) recorded simultaneously after partial sleep deprivation in 50 patients. We calculated the awake and sleep spike index (ASI and SSI, spikes/epoch), and the percentage increase of ASI and SSI during sleep. Results : In the 50 patients, the IEDs were recorded exclusively during the awake state in 1 (2%) patient, and during the sleep state in 13(26%) patients. The SSI was higher in 44 (88%) patients, and the ASI was higher in 5 (10%) patients. The mean ASI and the SSI in patients with organic brain lesions were $0.058{\pm}0.121$ and $0.148{\pm}0.187$, and it was $0.081{\pm}0.150$ and $0.174{\pm}0.226$ in patients without organic brain lesions. There were significant increases in the spike index (P<0.05) during NREM sleep in both groups (n=36), but no significant difference in the percent increase of spike index (P>0.05). Conclusion : The IEDs were activated significantly during NREM sleep both in patients with and without organic brain lesions, but there were no differences in the degree of activation in both groups. The activating effect of NREM sleep was not correlated with clinical factors such as, frequent nocturnal seizures, frequent generalized tonic clonic seizures, type of epilepsy and taking anticonvulsants. We conclude that the routine EEG used to evaluate epileptiform discharges in epileptic patients should include sleep recordings after partial sleep deprivation.