• Journal of Korean Neurosurgical Society
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• 제30권sup1호
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• pp.25-29
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• 2001

Objective : Intracranial metastasis is responsible for nearly 50% of mortalities of systemic cancers. Although its frequency is increasing and there is little doubt that improving the quality and expectancy of life is the final goal, the mode of treatment is still disputed. The authors report the postoperative motor function after surgery in patients with metastatic tumors around the motor cortex. Materials and Methods : We studied 24 patients with metastatic tumors around the central sulcus during the last 22 months. Motor function was assessed pre- and post-operatively as well as its response to corticosteroids. MRI, neuronavigation system and intraoperative ultrasonography were used for tumor localization and functional MRI and cortical stimulator were used to define the motor cortex. Results : Single metastasis was found in 13 cases(54%) and 11 cases(44%) had multiple foci. Thirteen cases were located in precentral, 7 in postcentral, and 4 in superior or middle-frontal lobe. The most common primary focus was the lung(16 cases). There was no difference in postoperative motor function improvement between the steroid responsive group and non-responsive group(92% versus 90%). Ninty-two percent of the patients showed significant improvement of motor function and lived independently but there was worsening in the upper extremity in one and in another no improvement. Whole brain radiation of 3000cGy was given in all cases and 4 patients died of recurrence in primary or intracranial focus during mean follow-up periods of 14 monthes. Conclusion : Surgery may provide substantial improvement of the motor function and quality of life of the patients with metastatic tumors around the motor cortex.

• Journal of Sasang Constitutional Medicine
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• 제25권3호
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• pp.145-157
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• 2013

Objectives This study was aimed to reveal the characteristics of the body shape, face, voice and temperament in Taeyangin. Methods The subjects were recruited from November 2005 to August 2012. Sasang constitutional specialist in each clinics confirmed the Sasang Constitution. Taeyangin (TY) became a standard guidance to be compared with each other Sasang type. Anova test was used in analyzing continuous variables and factor analysis was conducted in temperament questionnaire in advance. Generalized propensity score with age and body mass index (BMI) was used in adjusted model. Significant level was .05 Results 1. The TY body shape were generally smaller than Taeeumin (TE) (p<0.001) and Soyangin (SY) (p<0.05) in crude. The TY body shape were still smaller than TE (p<0.05) and there was no significant difference between TY and SY except rib circumference in males and forehead circumference (p<0.05) in females in adjusted model. 2. The size of face and nose in TY was smaller than in TE and there was different between males and females' TY and others in the characteristics of eye, nose and forehead variables in crude (p<0.05). Most of differences between TY and TE were disappeared in adjusted model. 3. The vocal height and speed of TY was different other types and there was different between males and females' TY in some of frequency change rate in crude (p<0.05). Most of differences between TY and other types were similar before and after adjusted model. 4. The temperament of TY was different with SE before and after adjusted mode 1 (p<0.05). TY males showed difference in expression factor and TY females showed difference in behavior factor compared with TE respectively (p<0.05). Conclusions This study reveals characteristics of body shape, face, voice and character in the TY males females compared with each other type respectively.

• Animal Systematics, Evolution and Diversity
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• nspc2호
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• pp.233-241
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• 1988

The crab, Macrophthalmus (Mareotis ) japonicus , collected in 1983 from CHojijin tidal flat, southeastern part of Kangwha Island , Korea, was studied. Its caraace breadth, the carapace length , and body height were checked , and the measured raw data were analysed for the growth ratios by the mode subtraction method from the frequency distribution compared with the probability graphs. The growth rate of the crab rose more in summer than in fall and exceeded 10% during the same period on Chojijin tidal flat in Kangwha Island , Korea. Four size groups of the crab appeared in June, 1983 , but they were put together into only on emixed group by autumn. The rapid growth of the crab in summer in middle latitude comes from the seasonal bio-rhythm and the best conditions for food. But the physiological activities of the crab are reduced from autumn and the growth rate reaches the upper limits in many individuals on this tidal flat. The more the crabs grow, the more the breadth ratios to the carapac length become larger and the slopes of correlation curve get smaller. The measured values from the carapace breadth of the crab are more useful for morphological studies than those values from the carapace length or body height.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제22권4호
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• pp.295-311
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• 2021

In this study, an experiment was carried out on the field applicability of tension measuring devices of the cables in cable-stayed bridges. The vibration method was used to estimate the tension of cables of cable-stayed bridge, and the mode characteristics of the cable were analyzed using a cable tension measuring device. GTDL360, NI Module, and 9 Axes Motion Sensorwere applied to estimate the cable tension of five target bridges. Numerical analysis of the five target bridges was conducted to analyze the natural frequency of the cable and cable tension. The estimated tension of the cable based on field measurements and estimated tension of cable by numerical analysis were compared with the estimated tension of the cable based on field measurements. The analysis showed that the measured tension of the cable based on field measurements was within the margin of error. Therefore, it is safe to apply these measuring devices to the site. As a result of comparing and analyzing the values of the acceleration-based cable estimation tension and numerical analysis of the field demonstration bridge, the acceleration-based cable estimation of tension is deemed appropriate within the allowable range. On-site applicability analysis revealed limitations of the measuring devices, such as the installation location of sensors and weather conditions, so continuous follow-up research on smart cable tension measuring systems is expected.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제22권3호
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• pp.777-783
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• 2021

Aircraft are affected by various vibrations during maneuvering. These vibrations may have a fatal effect on the survival of aircraft in some cases, so the safety of components applied to the aircraft should be proven against various vibrations through random vibration analysis. In this study, the structural robustness of an external fuel tank and pylon for military aircraft was evaluated under random vibration conditions using commercial software, MSC Random. In the random vibration analysis, a frequency response analysis was performed by imposing a unit load on the boundary condition point, and then excitation was performed with a PSD profile. In this process, the required mode data was extracted through a modal analysis method. In addition, the random vibration profile specified in the US Defense Environment Standard was applied as random vibration conditions, and the PSD profile given in units of G's was converted into units of gravitational acceleration. As a result of the numerical analysis, we evaluated the structural robustness of the external fuel tank and pylon by identifying the safety margins of beam elements, shell elements, and solid elements in a numerical model for random vibration in the x, y, and z directions.

• Journal of the Korean Physical Society
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• 제73권9호
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• pp.1362-1369
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• 2018

A method aimed at improving the beam-wave interaction efficiency by changing the coupling slot configuration has been proposed in the study of extended interaction oscillators (EIOs). The dispersion characteristics, coupling coefficient and interaction impedance of the high-frequency structure based on different types of coupling slots have been investigated. Four types of coupled cavity structures with different layouts of the coupling slots have been compared to improve the beam-wave interaction efficiency, so as to analyze the beam-wave interaction and practical applications. In order to determine the improvement of the coupling slot to a coupled cavity circuit in an EIO, we designed four nine-gap EIOs based on the coupled cavity structure with different coupling slot configurations. With different operating frequencies and voltages takes into consideration, beam voltages from 27 to 33 kV have been simulated to achieve the best beam-wave interaction efficiency so that the EIOs are able to work in the $2{\pi}$ mode. The influence of the Rb and the ds on the output power is also taken into consideration. The Rb is the radius of the electron beam, and the ds is the width of the coupling slot. The simulation results indicate that a single-slot-type EIO has the best beam-wave interaction efficiency. Its maximum output power is 2.8 kW and the efficiency is 18% when the operating voltage is 31 kV and electric current is 0.5 A. The output powers of these four EIOs that were designed for comparison are not less than 1.7 kW. The improved coupling-slot configurations enables the extended interaction oscillator to meet the different engineering requirements better.

• The Journal of the Acoustical Society of Korea
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• 제40권6호
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• pp.587-592
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• 2021

Change in the cortical thickness of long bones occurring with aging and osteoporosis is known to be a risk factor for fracture. The present study aims to investigate the dependencies of phase velocities of ultrasonic guided waves on the cortical thickness in 7 soft tissue-bone mimicking phantoms consisting of acrylic plates covered by a 2 mm-thick silicone rubber layer by using the axial transmission technique with a pair of transducers with a center frequency of 200 kHz and a diameter of 12.7 mm. Two distinct propagating waves with different velocities, the First Arriving Signal (FAS) and the Slow Guided Waved (SGW), were consistently observed for all the soft tissue-bone mimicking phantoms. The FAS velocity decreased slightly with increasing thickness, whereas the SGW velocity increased strongly with increasing thickness. The FAS and the SGW velocities were found to be closely consistent with the S0 and the A0 Lamb mode velocities for a free acrylic plate, respectively, suggesting that the presence of the soft tissue mimicking material (2 mm-thick silicone rubber layer) covering the acrylic plates does not influence significantly the velocity measurements.

• Steel and Composite Structures
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• 제48권2호
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• pp.207-233
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• 2023

Steel-concrete composite box girder bridges are widely used in the construction of highway and railway bridges both domestically and abroad due to their advantages of being light weight and having a large spanning ability and very large torsional rigidity. Composite box girder bridges exhibit the effects of shear lag, restrained torsion, distortion and interface bidirectional slip under various loads during operation. As one of the most commonly used calculation tools in bridge engineering analysis, one-dimensional models offer the advantages of high calculation efficiency and strong stability. Currently, research on the one-dimensional model of composite beams mainly focuses on simulating interface longitudinal slip and the shear lag effect. There are relatively few studies on the one-dimensional model which can consider the effects of restrained torsion, distortion and interface transverse slip. Additionally, there are few studies on vehicle-bridge integrated systems where a one-dimensional model is used as a tool that only considers the calculations of natural frequency, mode and moving load conditions to study the dynamic response of composite beams. Some scholars have established a dynamic analysis model of a coupled composite beam bridge-train system, but where the composite beam is only simulated using a Euler beam or Timoshenko beam. As a result, it is impossible to comprehensively consider multiple complex force effects, such as shear lag, restrained torsion, distortion and interface bidirectional slip of composite beams. In this paper, a 27 DOF vehicle rigid body model is used to simulate train operation. A two-node 26 DOF finite beam element with composed box beams considering the effects of shear lag, restrained torsion, distortion and interface bidirectional slip is proposed. The dynamic analysis model of the coupled composite box girder bridge-train system is constructed based on the wheel-rail contact relationship of vertical close-fitting and lateral linear creeping slip. Furthermore, the accuracy of the dynamic analysis model is verified via the measured dynamic response data of a practical composite box girder bridge. Finally, the dynamic analysis model is applied in order to study the influence of various mechanical effects on the dynamic performance of the vehicle-bridge system.

• The Journal of the Acoustical Society of Korea
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• 제25권1호
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• pp.21-29
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• 2006

In this Paper a split bandwidth wideband speech coder and its highband coding method are Proposed. The coder uses a split-band approach. where the wideband input speech signal is split into two equal frequency bands from 0-4kHz and 4-8kHz. The lowband and the highband are coded respectively by the 11.8kb/s G.729 Annex E and the proposed coding method. After the LPC analysis, the highband is divided by two modes according to the properties of signals. In stationary mode. the highband signals are compressed by the mixture excitation model; CELP algorithm and W (Matching Pursuit) algorithm. The others are coded by the only CELP algorithm. We compare the performance of the new wideband speech coder with that of G.722 48kbps SB-ADPCM and G.722.2 12.85kbps in a subjective method. The simulation results show that the Performance of the proposed wideband speech coder has better than that of 48kbps G.722 and no better than that of 12.85kbps G.722.2.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제60권3호
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• pp.258-268
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• 2024

We presented foundational findings regarding the occurrence and acoustic characteristics of the finless porpoise through passive acoustic and visual surveys conducted on the southern coast of Korea, specifically at Hadong Jungpyeong Port. Over a survey period spanning from July 8 to August 16, 2023, totaling 40 days, we observed peaks in the number of clicks produced by this species on July 15, July 24, August 4, August 11, and August 16. The highest count, totaling 18,924 clicks, was recorded on July 15th, while the lowest count, at 3,888 clicks, occurred on August 8th. Examining the acoustic characteristics throughout the diurnal cycle, we found that the peak activity in terms of DPM (detection positive minute for one hour), DP10M (DPM for ten minutes), and overall number of click sounds was observed between 05:00 and 08:00, with a secondary peak occurring from 17:00 to 18:00. The quietest period was noted between 23:00 and 02:00. Furthermore, there was a significant increase in the number of clicks from sunrise, with the maximum count of 21,581 clicks recorded at 6 AM. This count gradually decreased until noon, experienced a slight increase thereafter, peaked again at sunset, and then declined. The dominant frequency mode of this species was 126 kHz, with a concentration ranging from 112 to 136 kHz. The average duration of a click sound was 127 ㎲, with approximately 16 sinusoids (cycles) within each click sound and an average cycle length of approximately 7.9 ㎲. These findings from our study are anticipated to serve as foundational data for the development of a Korean pinger and acoustic warning system.