• Sleep Medicine and Psychophysiology
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• v.16 no.1
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• pp.5-9
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• 2009

Relatively little is known about the neurobiology of insomnia, despite its wide prevalence and broad medical impact. Although much is still to be learned about the pathophysiology of the disorder, identification, systematic assessment, and appropriate treatment are clearly beneficial to patients. Recent research, using quantitative EEG, polysomnography (PSG), multiple sleep latency test (MSLT) and neuroimaging techniques, suggests that some broad areas can be identified as possible pathophysiological models. Sleep-wake homeostat model hypothesizes a failure in homeostatic regulation of sleep, an attenuated increase in sleep drive with time awake, and/or defective sensing of sleep need. Circadian clock model hypothesizes a dysfunctional circadian clock, resulting in changes in the timing of sleep-wake propensity that are incompatible with normal sleep. Intrinsic sleep-wake state mechanism model suggests that abnormal function of insomnia comprises the systems responsible for expression of the sleep states themselves. Extrinsic over-ride mechanism (stress-response) model suggests that insomnia reflects the consequences of overactivity of one of the systems considered "extrinsic" to normal sleep-wake control. Many current therapies for insomnia are based on these physiological models. Several attempts have been made to create a physiological model that would explain this disorder and could be used as a foundation for treatment. However, it appeared that no model can fully explain and clarify all aspects of insomnia. Future research should be necessary to expand our knowledge on the biological dimensions of insomnia.

• Structural Engineering and Mechanics
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• v.52 no.6
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• pp.1193-1208
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• 2014

A simulation of failures on responsible elements is only one form of the extreme structural behavior analysis. By understanding the dynamic behavior in incidental situations, it is possible to make a special structural design from the point of the largest axial force, stress and redundancy. The numerical realization of one such simulation analysis was performed using FEM in this paper. The boundary parameters of transient analysis, such as overall structural damping coefficient, load accelerations, time of load fall and internal forces in the responsible structural elements, were determined on the basis of the dynamic experimental parameters. The structure eigenfrequencies were determined in modal analysis. In the study, the basic incidental models were set. The models were identified by many years of monitoring incidental situations and the most frequent human errors in work with heavy structures. The combined load models of structure are defined in the paper since the incidents simply arise as consequences of cumulative errors and failures. A feature of a combined model is that the single incident causes the next incident (consecutive timing) as well as that other simple dynamic actions are simultaneous. The structure was observed in three typical load positions taken from the crane passport (range-load). The obtained dynamic responses indicate the degree of structural sensitivity depending on the character of incident. The dynamic coefficient KD was adopted as a parameter for the evaluation of structural sensitivity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.132-139
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• 2008

The blade vibration problem of bladed disk is the most critical subject to consider since it directly affects the stable performance of the engine as well as life of the engine. Especially, due to complicated vibration pattern of the bladed disk, more effort was required for vibration analysis and test. The research of measuring the vibration of the bladed disk, using NSMS(Non-intrusive stress measurement) instead of Aeromechanics testing method requiring slip ring or telemetry system with strain gauge, was successful. These testing can report the actual stresses seen on the blades; detect synchronous resonances that are the source of high cycle fatigue (HCF) in blades; measure individual blade mis-tuning and coupled resonances in bladed disks. In order to minimize the error being created due to heat expansion, the tip timing sensor is installed parallel to the blade trailing edge, yielding optimal result. Also, when working on finite element analysis, the whole bladed disk has gone through three-dimensional analysis, evaluating the family mode. The result of the analysis matched well with the test result.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.2 no.1
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• pp.7-11
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• 2002

Isovaleric acidemia is an inborn error in metabolism due to a defect in isovaleryl-CoA dehydrogenase. Accumulation of serum isovaleric acid causes poor feeding, vomiting, lethargy, hypothermia, convulsion, mental retardation, etc. It is inherited as an autosomal recessive trait. Since the first reports of isovaleric acidemia by Tanaka et al in 1966, more than 60 cases have been reported. There are two clinically different presentations of isovaleric acidemia, with about half the patients presenting with an acute severe neonatal form and about half with a chronic intermittent form. The difference in clinical presentation may not be a consequence of differing severities of the causative mutation, but a result of the timing of application of catabolic stress or the ability to form isovalerylglycine. We described here clinical and organic acid analytical findings of in 3 cases isovaleric acidemia.

• BMB Reports
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• v.50 no.5
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• pp.235-236
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• 2017

The circadian clock is an internal system that is synchronized by external stimuli, such as light and temperature, and influences various physiological and developmental processes in living organisms. In the model plant Arabidopsis, transcriptional, translational and post-translational processes are interlocked by feedback loops among morning- and evening-phased genes. In a post-translational loop, plant-specific single-gene encoded GIGANTEA (GI) stabilize the F-box protein ZEITLUPE (ZTL), driving the targeted-proteasomal degradation of TIMING OF CAB EXPRESSION 1 (TOC1) and PSEUDO-RESPONSE REGULATOR 5 (PRR5). Inherent to this, we demonstrate the novel biochemical function of GI as a chaperone and/or co-chaperone of Heat-Shock Protein 90 (HSP90). GI prevents ZTL degradation as a chaperone and facilitates ZTL maturation together with HSP90/HSP70, enhancing ZTL activity in vitro and in planta. GI is known to be involved in a wide range of physiology and development as well as abiotic stress responses in plants, but it could also interact with diverse client proteins to increase protein maturation. Our results provide evidence that GI helps proteostasis of ZTL by acting as a chaperone and a co-chaperone of HSP90 for proper functioning of the Arabidopsis circadian clock.

• Structural Engineering and Mechanics
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• v.36 no.4
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• pp.513-527
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• 2010

This paper presents a three-dimensional finite element method based structural analysis model for structural analysis of reinforced concrete high-rise buildings during construction. The model considered the time-dependency of the structural configuration and material properties as well as the effect of the construction rate and shoring stiffness. Uniaxial compression tests of young concrete within 28 days of age were conducted to establish the time-dependent compressive stress-strain relationship of concrete, which was then used as input parameters to the structural analysis model. In-situ tests of a RC high-rise building were conducted, the results of which were used for model verification. Good agreement between the test results and model predictions was achieved. At the end, a parametric study was conducted using the verified model. The results indicated that the floor position and construction rate had significant effect on the shore load, whereas the influence of the shore removal timing and shore stiffness have much smaller. It was also found that the floors are more prone to cracking during construction than is ultimate bending failure.

• Speech Sciences
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• v.1
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• pp.7-26
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• 1997

An electromyographic device was used to investigate the relationship between a linguistic hypothesis of tense-lax distinction and muscular activity. Muscle action potentials of the orbicularis oris muscle and the depressor anguli oris muscle were obtained from four subjects using CVCVCV and CVCVC words in English and VCV and CVC words in Korean. Findings: The hypothesis that the speaker may select at least one of muscles involved in the articulation of a phoneme so that the selected muscle could be activated for tense-lax distinction, and either a timing variable or an amplitude variablethe and/or both from the selected muscle distinguish(es) /p/ from /b/ in English and /$p^{h},\;p^{l}$/ from /p/ in Korean, with the English /p/ and the Korean /$p^{h},\;p^{l}$/ being tense, and the Korean unaspirated /p/ and the English /b/ lax, has been verified, except for the case with subject 2 in stressed syllables in English. (2) Thus, the linguistic hypothesis of tense-lax distinction was strongly supported by the muscular activities during the Korean bilabial stops, with /$p^{h}\;and\;p^{l}$/ being tense and /p/ lax. (3) Considering the intermuscle compensation and the interspeaker variabilities in the choice of a muscle or muscles, in English the usability of the feature 'tensity' appeared to be positive rather than negative although further investigations with more subjects remain to take on the muscles associated with the onset/offset of the labial closure, including the respiratory muscles related with the aspiration. The phoneme-sensitive EMG manifestations of stress and possible reasons for the interspeaker variabilities are discussed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.871-876
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• 2008

The blade vibration problem of bladed disk is the most critical subject to consider since it directly affects the stable performance of the engine as well as life of the engine. Especially, due to complicated vibration pattern of the bladed disk, more effort was required for vibration analysis and test. The research of measuring the vibration of the bladed disk, using NSMS(Non-intrusive stress measurement) instead of Aeromechanics testing method requiring slip ring or telemetry system with strain gauge, was successful. These testing can report the actual stresses seen on the blades; detect synchronous resonances that are the source of high cycle fatigue(HCF) in blades; measure individual blade mis-tuning and coupled resonances in bladed disks. In order to minimize the error being created due to heat expansion, the tip timing sensor is installed parallel to the blade trailing edge, yielding optimal result. Also, when working on finite element analysis, the whole bladed disk has gone through three-dimensional analysis, evaluating the family mode. The result of the analysis matched well with the test result.

• Journal of Korean Neurosurgical Society
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• v.64 no.4
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• pp.665-670
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• 2021

Symptomatic cerebral vasospasm (CVS) and delayed ischemic neurologic deficit (DIND) after unruptured aneurysm surgery are extremely rare. Its onset timing is variable, and its mechanisms are unclear. We report two cases of CVS with DIND after unruptured aneurysm surgery and review the literature regarding potential mechanisms. The first case is a 51-year-old woman with non-hemorrhagic vasospasm after unruptured left anterior communicating artery aneurysm surgery. She presented with delayed vasospasm on postoperative day 14. The second case is a 45-year-old woman who suffered from oculomotor nerve palsy caused by an unruptured posterior communicatig artery (PCoA) aneurysm. DIND with non-hemorrhagic vasospasm developed on postoperative day 12. To our knowledge, this is the first report of symptomatic CVS with oculomotor nerve palsy following unruptured PCoA aneurysm surgery. CVS with DIND after unruptured aneurysm surgery is very rare and can be triggered by multiple mechanisms, such as hemorrhage, mechanical stress to the arterial wall, or the trigemino-cerebrovascular system. For unruptured aneurysm surgery, although it is rare, careful observation and treatments can be needed for postoperative CVS with DIND.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.1
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• pp.19-24
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• 2023

In traditional fish farming way, the workers have to observe all of the pools every time and every day to feed at the right timing. This method causes tremendous stress on workers and wastes time. To solve this problem, we implemented an automatic detection system for feeding time using deep neural network. The detection system consists of two steps: classification of the presence or absence of feed and checking DO (Dissolved Oxygen) of the pool. For the classification, the pretrained ResNet18 model and transfer learning with custom dataset are used. DO is obtained from the DO sensor in the pool through HTTP in real time. For better accuracy, the next step, checking DO proceeds when the result of the classification is absence of feed several times in a row. DO is checked if it is higher than a DO reference value that is set by the workers. These actions are performed automatically in the UI programs developed with LabVIEW.