• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.1 s.24
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• pp.50-59
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• 2006

Lately, there exist growing demands for the use of CTAs(Cased Telescoped Ammunitions) to increase the firepower of mid-calibre automatic guns despite spatial limitations of armament. In this paper, for automatic CTA guns a rotating chamber mechanism is designed based on parallel index concept. Via dynamic simulations it proves capable of smooth operation even at as high a firing rate as 200spm. Subsequently, motor controllers are synthesized to drive the chamber at any constant speed and also to control positions in the presence of large disturbances caused by the intermittently-rotating load. It is remarkable that we successfully adopted a disturbance observer to treat disturbances only with a moderate bandwidth of the closed-loop system.

• Sleep Medicine and Psychophysiology
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• v.5 no.2
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• pp.210-215
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• 1998

OSA(Obstructive Sleep Apnea) is a condition with repeated obstruction of the upper airway while sleeping. This obstruction of the upper airway may result if sleep-induced physiologic change in muscle activity is superimposed on various structural defects of the upper airway. Macroglossia, micrognathia, retrognathia, and decreased airway lumen have all been implicated in OSA. There are a variety of surgical and nonsurgical treatment modalities currently available for OSA. Recently the uvulopalatopharyngoplasty has achieved widespread use, but success rates vary and long-term effects are still unknown. Current nonsurgical treatment methods can be cumbersome and uncomfortable with variable responses. For this case. we diagnosed as OSA by using polysomnographic analysis and cephalometric analysis, and delivered intraoral removable appliance which is more conservative, reversible and easy to use for patient. And we got results that Apnea Index(AI) decreased from 14.4 to 3.1, Total Respiratory Disturbance Index(Total RDI) decreased from 18.1 to 7.0 and removal of chronic headache in daytime.

• Sleep Medicine and Psychophysiology
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• v.18 no.2
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• pp.63-66
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• 2011

It has been controversial whether upper airway resistance syndrome (UARS) is a distinct syndrome or not since it was reported in 1993. The International Classification of Sleep Disorders classified UARS under obstructive sleep apnea syndrome (OSAS) in 2005. UARS can be diagnosed when the apnea-hypopnea index (AHI) is fewer than 5 events per hour, the simultaneously calculated respiratory disturbance index (RDI) is more than 5 events per hour due to abnormal non-apneic non-hypopneic respiratory events accompanying respiratory effort related arousals (RERAs), and oxygen saturation is greater than 92% at termination of an abnormal breathing event. Although esophageal pressure measurement remains the gold standard for detecting subtle breathing abnormality other than hypopnea and apnea, nasal pressure transducer has been most commonly used. RERAs include phase A2 of cyclical alternating patterns (CAPs) associated with EEG changes. Symptoms of OSAS can overlap with UARS, but chronic insomnia tends to be more common in UARS than in OSAS and clinical symptoms similar with functional somatic syndrome are also more common in UARS. In this journal, diagnostic and clinical differences between UARS and OSAS are reviewed.

• The Korean Journal of Food And Nutrition
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• v.21 no.2
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• pp.256-262
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• 2008

This study was carried out to compare the hair mineral status of obese, over-weighted and non-obese individuals, to gather basic data for customizing menu development and to create an education manual for the obese persons. Food preferences or various disease states could be suggested by different mineral patterns in TMA(tissue mineral analysis). The results indicated that Zn status was considerably lower in the obese individuals than in the non-obese(p<0.001) whereas hair Na(p<0.0001), K(p<0.01) and Fe(p<0.05) were at significantly higher levels in the obese individuals. The ratio of Ca/K(p<0.001) was significantly lower in the obese than in the non-obese. But the levels of hair toxic minerals such as Sb, As, Hb, Al et al. were not differ according to BMI groups. The obtained data demonstrate the changes of hair mineral content in both overweight and obese individuals thus suggesting metabolic mineral disturbance in those groups.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.1
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• pp.18-25
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• 2000

In the two-mass servo system driving a load through a flexible shaft, a shaft torsional vibration is often generated. PI controller has been generally used is speed control of such system because of the simplicity of structure and related theory. This paper presents the inertia ratio of the PI servo control system which can be designed by using optimal pole assignment method is fixed. Therefore, it's difficult to obtain the desired control characteristics for different systems only by PI control algorithm. To solve this problems the two-mass speed control system with PID controller is designed by using pole assignment method and an optimum PID parameters are derived by evaluating ITAE(Integral of time multiplied by the absolute error) performance index. But this design method has some problems due to a trade-off between the fast command following property and the attenuation of disturbances and vibrations. In this paper, 2-DOF PID control method which satisfies the command following property, the reduction of overshoot and the property of disturbance rejection at the same time is proposed. This is a practical speed controller using the desired value filter and the feedforward gain. From several simulations, it's clarified that the proposed 2-DOF PID controller is useful for the two-mass system, in comparison with the conventional PID controller.

• The Korean Journal of Ecology
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• v.11 no.4
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• pp.213-225
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• 1988

The plant communities of the eastern ridge in Mt. Cheonma, Central Korea, Quercus mongolica, Q mongolica-Acer pseudo-sieboldianum, and Q. mongolica-Rhododendron schlippenbachii communities in the northern slope and Q. variabilis and Q. cutissima communities in the southern slope were detected by Zurich-Montpellier method. The undergrowth of Q mongolica community in the northern slope was dominated by Ainsliaea acerifolia, Carex siderosticta, Astilbe chinensis var. davidii, Heloniopsis orientalis, Pseudostellaria palibiniana, ranging 3.3 to 2.2 in dominance-sociability, while the those of Q variabilis and Q acutissima in the southern slope were dominated by Spodiopogon cotulifer, Artemisia keiskeana, Carex humilis, Atractylodes japonica, Lysimachia clethroides and Disporum smilacinum with similar degree in dominance-sociability to that of Q mongolica community. The two communities were considered as regenerating forest after severe disturbance judging by their age structure. The relationship between Shannon's diversity index (H') and Simpson's dominance index (i) was in reciprocal proportion in both two communities. The Q. mongolica and Q. variabilis communities were showed 13 and 12 m respectively. Seasonal changes of undergrowth coverage in the two communities were seemed to be affected especially with soil moisture among environmental factors such as temperature, light intensity, relative humidity and organic matter.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.494-501
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• 1999

In this research, ANN modeling method of SMES unit is developed for stability analysis, and the optimal site is selected to maximize stabilization effect of SMES unit. The ANN is trained by learning data which is obtained through the application of complex test function into the traditional mathematical mode. In order to verify the validity of proposed modeling method, fault data of sample power system is applied to both the traditional and the ANN models. When the response of traditional and proposed models are compared, the average error for the active and reactive power are 2.51[%], and 0.24[%], respectively. From the comparison, the relevance of proposed method is validated. For the transient stability analysis, an application method of the proposed model is presented, and the transient stability performance index, which describes system stabilization effect of SMES at disturbance, is also suggested, and optimal site selection method of SMES is presented. In the viewpoint of the voltage stability, system stabilization criterion of local bus is presented from P­V curve, and then optimal site which can maximize the voltage stabilization of the whole power system, is decided from the proposed voltage stability performance index.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.4
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• pp.67-89
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• 2022

This study aimed to elucidate the distribution of vascular plants on the Deok mountain in Ganghwa-gun, Korea. The results of 10 field surveys from March to October of 2019 identified 532 taxa in total, representing 482 species, 9 subspecies, 39 varieties, 1 form, and 1 hybrid in 318 genera and 105 families. The plant formation of Deok mountain is the deciduous broad-leaved and conifer mixed forest, which is the common one in the middle region of the Korean Peninsula. Among them, 301 taxa were newly recorded in this study, 7 taxa were endemic plants to Korea, 3 taxa were red list plants. The floristic target plants amounted to 41 taxa, specifically 1 taxon of grade V, 2 taxa of grade IV, 7 taxa of grade III, 9 taxa of grade II, and 22 taxa of grade I. Alien plants were recorded a total of 73 taxa with a naturalized index of 13.7%, the urbanization index was calculated to be 11.8% and 4 taxa were ecosystem disturbance plants.

• Current Optics and Photonics
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• v.8 no.1
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• pp.30-37
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• 2024

Implemented at the Geochang Observatory in South Korea, our slope detection and ranging (SLO-DAR) system features a 508 mm Cassegrain telescope (f /7.8), incorporating two Shack-Hartmann wave-front sensors (WFS) for precise measurements of atmospheric phase distortions, particularly from nearby binary or double stars, utilizing an 8 × 8 grid of sampling points. With an ability to reconstruct eight-layer vertical atmospheric profiles, the system quantifies the refractive index structure function (C_n²) through the crossed-beam method. Adaptable in vertical profiling altitude, ranging from a few hundred meters to several kilometers, contingent on the separation angle of binary stars, the system operates in both wide (2.5 to 12.5 arcminute separation angle) and narrow modes (11 to 15 arcsecond separation angle), covering altitudes from 122.3 to 611.5 meters and 6.1 to 8.3 kilometers, respectively. Initial measurements at the Geochang Observatory indicated C_n² values up to 181.7 meters with a Fried parameter (r₀) of 8.4 centimeters in wide mode and up to 7.8 kilometers with an r₀ of 8.0 centimeters in narrow mode, suggesting similar seeing conditions to the Bohyun Observatory and aligning with a comparable 2014-2015 seeing profiling campaign in South Korea.

• Journal of the Korean Geosynthetics Society
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• v.23 no.1
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• pp.39-47
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• 2024

In this study, physical property tests and standard consolidation tests were conducted on the marine clay of Busan New Port and North Port, the middle and lower reaches of the Nakdong River including Gimhae and Yangsan, and Ulsan regions. The moisture content, a property unrelated to sample disturbance with small individual test errors, was used for regression analysis with the compression index, virgin compression index, consolidation coefficient, expansion index, and secondary compression index, among others. Subsequently, the correlation and accuracy were evaluated. Upon analyzing the correlation between the moisture content, void ratio, and liquid limit commonly used physical properties for calculating compression indexes, it was confirmed that the liquid limit had the lowest correlation. Through a linear regression analysis of the consolidation constants using the current moisture content in the natural state, a high correlation was demonstrated. Relationship equations were then presented to determine settlement and settlement time. This study suggests that moisture content can be utilized as an alternative for evaluating and calculating consolidation constants when examining ground settlement in sedimentary clays distributed in the Busan and Gyeongnam regions.