• Proceedings of the Mineralogical Society of Korea Conference
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• 2002.05a
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• pp.1-3
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• 2002

The eastward extension of the suture zone between the Sino-Korea and Yangtze cratons in the Korean Peninsula and Japanese islands remains debatable (Hiroi, 1981; Cluzel et al., 1991; Yin and Nie, 1993; Sohma and Kunugiza, 1993; Isozaki, 1997; Arakawa et at., 2000), and is related to our understanding of the continent-continent collision orogeny. The collision orogeny varies in tectono-metamorphic processes and the timing differs from place to place, as exemplified by the absence of coesite and micro-diamond in the Korean Peninsula and Japanese islands, because it is a long-lived process of more than several tens of million years from subduction to exhumation in the Wilson cycle, and because the suture zone extends more than several thousand kilometers with a curved shape from the Qinling area of China to the Hida highland area of Japan. Hiroi (1981) is the first paper to correlate the Unazuki metamorphic rocks of the Hida metamorphic belt in Japan with the Ogcheon belt in the Korean Peninsula based on the presence of 240 Ma medium P/T metamorphic rocks in both belts, but there is a lack of recent studies on this correlation. To resolve the correlationship, there are two approaches: 1) petrological studies characterizing the origin and P-T history of rocks and 2) in-situ micro-dating of fine-grained, zoned minerals of zircon, monazite, uraninite and thorite using the EPMA (U-Th-Pb chemical dating or CHIME depending on calibration method) and the SHRIMP (Sensitive High-resolution ion Microprobe) to decipher the timing of geological events. As a first step of these approaches, micro-dating was undertaken to rocks of the Hida metamorphic belt and its Mesozoic cover (Tetori Group) in the Hida highland area, central Japan.

• Speech Sciences
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• v.9 no.1
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• pp.17-26
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• 2002

Voice onset time (VOT) is defined as the time interval from the oral release of a stop consonant to the onset of glottal pulsing in the following vowel. VOT is a temporal characteristic of stop consonants that reflects the complex timing of glottal articulation relative to supraglottal articulation. There have been many reports on efforts to clarify the acoustical and physiological properties that differentiate the three types of Korean stops, including acoustic, fiberscopic, aerodynamic and electromyographic studies. In the acoustic and fiberscopic studies for stop consonants, the voice onset time and glottal width during the production of stops has been known as the longest and largest in the heavily aspirated type followed by the slightly aspirated type and unaspirated types. The thyroarytenoid and posterior cricoarytenoid muscles were physiologically inter-correlated for differentiating these types of stops. However, a review of the English literature shows that the fine movement of the mucosal edges of the vocal folds during the production of stops has not been well documented. In recent. years, a new method for high-speed recording of laryngeal dynamics by use of a digital recording system allows us to observe with fine time resolution. The movements of the vocal fold edges were documented during the period of stop production using a fiberscopic system of high speed digital images. By observing the glottal width and the visual vibratory movements of the vocal folds before voice onset, the heavily aspirated stop was characterized as being more prominent and dynamic than the slightly aspirated and unaspirated stops.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.4
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• pp.384-395
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• 2012

This study was performed to develop the source profiles for fine particles ($PM_{2.5}$) emitted from the biomass burning. The multi-method research strategy included a usage of combustion devices such as field burning, fireplace, and residential wood burning to burn rice straw, fallen leaves, pine tree, and oak tree. The data were collected from multiple sources and measured water-soluble ions, elements, elemental carbon (EC), and organic carbon (OC). From this study, it turned out that OC (34~67%) and EC (1.2~39%) are the major components emitted from biomass burning. In the case of burning rice straw at field burning, OC (66.6%) was the most abundant species, followed by EC (4.3%), $Cl^-$ (3.6%), Cl (2.1%), and $SO^{2-}_4$(1.9%). Burning rice straw, fallen leaves, pine tree, and oak tree at fireplace, the amount of OC was 58.5%, 52.7%, 52.5%, and 61.2%, and that of EC was 1.2%, 18.4%, 36.5%, and 2.7%, respectively. The ratio of OC for the burning of pine tree and oak tree from the residential wood burning device was 56.9% and 34.3%, and that of EC was 25% and 38.6%, respectively. Applying the measured data with respect to the proportion of components emitted from biomass burning to reference model, it turned out that self-diagnosed result was appropriate level, and the result based on the model is in highly corresponding to actual timing of biomass burning.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1086-1095
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• 2007

This paper proposes a novel non-coherent TOA estimation scheme using multiple correlation process on the existence of multiple simultaneously operating piconets (SOPs). Impulse radio-ultra wideband (IR-UWB) based on direct sequence spread spectrum (DSSS) using Gold sequence is employed in order to discriminate each piconet. In order to enhance the characteristic of correlation, this paper presents the method of multiple mask operation (MMO). The time of arrival (TOA) of direct line of sight (DLOS) path is estimated via two step coarse/fine timing detection. To verify the performance of proposed scheme, two distinct channel models approved by IEEE 802.15.4a Task Group (TG) are considered. According to the simulation results, it could conclude that the proposed scheme have performed better performance than the conventional method well even in densed indoor multi-path environment as well as in the existence of multiple SOPs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.57-64
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• 2020

Recently, due to the proliferation of IoT sensors, the development of big data and artificial intelligence, time series prediction research on fine dust pollution is actively conducted. However, because the data representing fine dust contamination changes rapidly, traditional time series prediction methods do not provide a level of accuracy that can be used in the field. In this paper, we propose a method that reflects the classification results of environmental conditions through CNN when predicting micro dust contamination using LSTM. Although LSTM and CNN are independent, they are integrated into one network through the interface, so this method is easier to understand than the application LSTM. In the verification experiments of the proposed method using Beijing PM2.5 data, the prediction accuracy and predictive power for the timing of change were consistently improved in various experimental cases.

• Journal of the Korean earth science society
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• v.33 no.5
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• pp.434-449
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• 2012

The Mesozoic leucocratic granite in the northeastern margin of the Taebaeksan Basin was transformed to protomylonite and mylonite. Mylonitic foliations generally strike to NWWNW and dip to NE with the development of a sinistral strike-slip (top-to-the-northwest) shear sense. Grain-size reduction of feldspar in the mylonitized leucocratic granite occurred due to fracturing, myrmekite formation and neocrystallization of albitic plagioclase along the shear fractures of K-feldspar porphyroclasts. As the deformation proceeded, compositional layering consisting of feldspar-, quartz- and/or muscovite-rich layers developed in the mylonite. In the feldspar-rich layer, fine-grained albitic plagioclase and interstitial K-feldspar were deformed dominantly by granular flow. On the other hand, quartz-rich layers containing core-mantle and quartz ribbons structures were deformed by dislocation creep. Based on calculations from conventional two-feldspar and ternary feldspar geothermometers, mylonitization temperatures of the leucocratic granite range from 360 to $450^{\circ}C$. It thus indicates that the mylonitization has occurred under greenschist-facies conditions. Based on the geochemical features and previous chronological data, the leucocratic granite was emplaced during the Middle Jurassic at volcanic arc setting associated with crustal thickening. And then the mylonitization of the granite occurred during the late Middle to Late Jurassic (150-165 Ma). Therefore, the mylonitization of the Jurassic granitoids in the Taebaeksan Basin was closely related to the development of the Honam shear zone.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.79-89
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• 2002

A synchronization method is presented for IEEE 802.11a wireless OFDM system. First the coarse symbol synchronization is achieved by measuring the moving power average of the received envelope signal. The detection probabilities and optimum thresholds for the symbol synchronization are derived. By measuring the correlation between the short training signal and received envelope signal, fine symbol synchronization can be acquired. And the frequency synchronization is achieved using long training signal. A symbol synchronization error causes a phase rotation of the constellation. After the compensation for fading channel, the rotation due to the symbol timing error can be corrected. With this method, synchronization can be well achieved over frequency selective channels.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.565-573
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• 2017

This paper presents a multistage in-flight alignment (MIFA) method for a strapdown inertial navigation system (SDINS) suitable for moving vehicles with no initial attitude references. A SDINS mounted on a moving vehicle frequently loses attitude information for many reasons, and it makes solving navigation equations impossible because the true motion is coupled with an undefined vehicle attitude. To determine the attitude in such a situation, MIFA consists of three stages: a coarse horizontal attitude, coarse heading, and fine attitude with adaptive Kalman navigation filter (AKNF) in order. In the coarse horizontal alignment, the pitch and roll are coarsely estimated from the second order damping loop with an input of acceleration differences between the SDINS and GPS. To enhance estimation accuracy, the acceleration is smoothed by a scalar filter to reflect the true dynamics of a vehicle, and the effects of the scalar filter gains are analyzed. Then the coarse heading is determined from the GPS tracking angle and yaw increment of the SDINS. The attitude from these two stages is fed back to the initial values of the AKNF. To reduce the estimated bias errors of inertial sensors, special emphasis is given to the timing synchronization effects for the measurement of AKNF. With various real flight tests using an UH60 helicopter, it is proved that MIFA provides a dramatic position error improvement compared to the conventional gyro compass alignment.

• International Journal of Automotive Technology
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• v.7 no.3
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• pp.277-282
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• 2006

With the aim of achieving half the regulated value of EURO-3 Emission Regulations, an ultra low emission motorcycle has been developed based on a motorcycle with an 1800 $cm^3$, horizontal opposed 6-cylinder engine. For the fuel supply system, an electronically controlled fuel injection system was applied. For the emission purification system, three-way catalysts, a feedback control system with a LAF(Linear Air-Fuel ratio) sensor, and a secondary air induction system were applied. To reduce CO and HC emissions during cold starting, an early catalyst activation method combining RACV(Rotary Air Control Valve) and retarded ignition timing was applied. After the catalyst activation, air-fuel ratio was controlled to maximize the purification ratio of the catalyst according to vehicle speed. For the air-fuel ratio control system, the LAF sensor was used. Furthermore, fine adjustment by the LAF feedback control reduced torque fluctuation due to the air-fuel ratio change. As a result, smooth ride feeling was maintained. Owing to these technologies, half the regulated value of EURO-3 has been achieved without any negative impact to the large-scaled motorcycles' drivability. This paper presents the developed ultra low emission technologies including the control method using an LAF sensor.

• Journal of The Geomorphological Association of Korea
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• v.24 no.4
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• pp.91-101
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• 2017

The Okjukdong dune in Daecheong Island attracts national attention because of its unique landscape that is not covered by vegetation. However, there has been little knowledge on the timing of the dune formation, associated wind regime, and conservational strategies. In this study, we used OSL dating and grain size analyses to reveal the history of the dune development. In addition, we analyzed the wind regime in the dunefield which is surrounded by artificial coastal forest. The fine sand at Okjukdong underlain by a colluvial gravel layer indicates that the dune has been developed since at least 5 ka. Aeolian sands were found to be deposited around 700 years ago. The dunefield appears to have been severely eroded 30~60 years ago. The dune landscape has been destroyed after constructing a windbreak forest around the dunefield. The sand seems to be moving south and north with the season.