• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1796-1803
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• 2006

This Paper describes a systematic method for designing the $H_{\infty}$ controller for the inverted pendulum which is a nonlinear and single-input double-outputs system. In particular, the open-loop system is conbined with a pre-filter to shape the open-loop transfer function for the sensitivity function ind the complementary sensitivity function to be kept the desirable frequency characteristics. Consequently, the loop shaping technique of the open-loop transfer function reduces the impacts of the model uncertainties, measurement noises and exogenous disterbances on the dynamic characteristics of the inverted pendulum. The results of simulation and experiment show the efficiency of the proposed control method comparing with conventional PID control method.

• The KIPS Transactions:PartC
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• v.18C no.1
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• pp.7-14
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• 2011

Power analysis attack on low-power consumed security devices such as smart cards is very powerful, but it is required that the correlation between the measured power signal and the mid-term estimated signal should be consistent in a time instant while running encryption algorithm. The power signals measured from the security device applying the random clock do not match the timing point of analysis, therefore random clock is used as counter measures against power analysis attacks. This paper propose a new constant pitch based time alignment for power analysis with random clock power trace. The proposed method neutralize the effects of random clock used to counter measure by aligning the irregular power signals with the time location and size using the constant pitch. Finally, we apply the proposed one to AES algorithm within randomly clocked environments to evaluate our method.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.273-277
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• 2001

Traditional methods of chemical analysis for the soil properties take time and produce harmful waste. The purpose of this research was to evaluate an NIR technique for measuring some soil properties that are rapid and accurate in soil fertility assessments. The NIR instrument (InfraAlyzer 500, Bran & Luebbe Co.) was used for obtaining spectral data from 140 finely ground soil for calibrations and validation estimating pH, CEC, extractable Ca, Mg, K, $SiO_2$, humic acid and EC. Partial least square regression analysis was used to develop a calibration of NIR spectroscopy method. The results indicated that NIR spectroscopy could be used as a routine nondestructive method quantitatively determining soil chemical properties quickly. However the NIR technique may require sample preparation to obtain even diffuse reflection spectra from the soil and data manipulations to obtain optimal predictions.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.76-79
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• 2005

The coexistence of mesenchymal tumor and carcinoma in the esophagus is extremely rare. We report a case of squamous cell carcinoma located at the mucosal surface over leiomyoma of the esophagus. A 76-year-old man with complaints of 3 months onset of odynophagia was diagnosed preoperatively as squamous cell carcinoma over submucosal tumor with calcification. Esophagectomy and esophagogastrostomy were performed through the right thoracotomy and upper median laparotomy. The patient is doing well without evidence of recurrence in the 25 months after resection. We discuss the pathogenesis and possible relations between the two tumors.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.69-69
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• 2012

지구상에는 약 40만 종의 식물이 존재하는 것으로 알려져 있으며 이 중에 는 질병의 치료를 위한 약재로 이용되거나 나무는 대부분 목재 등으로 이용된다. 향나무(Juniperus chinenesis L.)는 항균성 및 방충성이 뛰어난 상록수로서 목재는 조각재나 가구재로 사용되고 민간 및 한의학에서 다양한 증상의 약재로 쓰이고 있으며 부패한 냄새를 제거할 목적이나 향재 및 향료로도 쓰이고 있다. 열매의 정유성분은 화장품, 술, 캔디 등에 사용되며 cedrol은 향료보류제, 유분은 훈향료, 목부는 고혈압, 곽란, 심복통, 통기파혈에 쓰인다. 향나무는 폴레페놀 성분이 함유되어 있고 피톤치드가 많이 나오는 것으로 알려져 있으며 심재의 폴리페놀 화합물은 항암, 항균, 항알러지, 노화방지 및 심장질환 등을 예방하거나 지연시키는 등 광범위한 약리학적 활성을 나타내어 식품, 의약품, 화장품, 향료등 다양한 분야에 활용되고 있다. 향나무 추출물에 관한 연구로는 성분분석과 생리활성 등에 관한 의약학 분야의 다양한 연구와 항산화, 항균활성 등 약리작용에 연구가 최근 다양하게 이루어지고 있는 것을 볼 수 있다. 측백나무속에 속하는 나무들은 대부분 정유 성분을 함유하고 있는 특성으로 항균성 등 바이오 기능성 소재 개발을 위한 연구가 활발히 진행되고 있으나, 향나무 추출물의 염색성에 관한 연구는 찾아보기 어려운 실정이다. 이에 본 연구에서는 다양한 용매를 이용하여 향나무의 잎, 열매, 수피, 심재 각 부위 추출물을 이용하여 견직물에 대한 염색성을 살펴봄으로써 향나무 추출물을 활용한 천연염색과 염재로서의 가능성을 확인하고자 하였다. 실험 결과 증류수를 염액 용매로 염색한 결과 모든 추출물의 잎, 열매 염색포의 색상은 대부분 옅은 Y계열로 나타났으며 향나무의 수피와 심재 염색포는 대부분 적색기미가 강한 YR계열로 나타났다. 에탄올 혼합액을 염액 용매로 하여 염색한 결과 향나무의 잎과 열매의 색상은 대부분 Y계열의 색상을 나타냈고 유기용매 추출염색포에서 정유성분으로 추정되는 물질 때문에 균염이 어려웠으며 수피와 심재 염색포에서 대부분 R계열의 색상이 뚜렷이 나타났다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7380-7384
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• 2014

Evacuation fire doors were manufactured by applying phosphorescent paint to the whole fire door whose performance was already recognized, and applying heat sensitive paint around the grip. The facility was improved by the evacuation and safety functions on the fire door, which has been used as only a fire facility, and the fire door is also used as an evacuation facility. The brilliance of the evacuation safety fire door manufactured in this study passed the brilliance test of Korea Fire Institute with a performance more than the brilliance (7mcd after 60 minutes) of the existing inducement sign. During a fire, the visible area is larger than the evacuation door inducement, etc. and light preventive status in the lower part of the fire door was observed during the descent of smoke. Therefore, it is considered to extend the evacuation effective time of evacuators. In heat sensitive paint applied around the grip, a color change is observed on the fire door when approaching a certain temperature ($70^{\circ}C$). Therefore, the first disaster that evacuators can encounter on the grip of a fire door during a fire can be prevented and should be helpful in recognizing the backfiring possibility and preventing safety accidents for firefighters who must enter a fire space.

• Journal of Labour Economics
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• v.28 no.3
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• pp.1-37
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• 2005

This article examines the reasons for the observed discrepancy between worker's actual and required levels of schooling and the resulting economic effects in wage and labor mobility using KRIVET's Graduates Economic Activities Survey in 2005. Overeducated workers in Korea are estimated to be 10.1%-20.7% among junior college graduates and 18.8% among university graduates for their first job according to job analysis method and worker's self-assessment method each. The effects of school quality-measured by the student/teacher ratio, school building area/student ratio-on the overeducation of their graduates are found to be mostly insignificant not only junior colleges but also universities. This founding implies that the increase of education investment from schools does not acquire any recognition from the labor market. Also, the effects of overeducation and school quality on wages are found to be insignificant and job mobility has little effects on improving overeducated workers' job match.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.1
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• pp.68-74
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• 2002

This study was performed to examine the availability of electrolysis for removal of remaining biologically refractoty humus and residual color of leachate which is biologically pretreated in domestic waste matter sanitary landfill by recycling to landfill. The obtained results were as follows; 1) The electrolysis of leachate through covered bed represented that the removal efficiency of CODcr and color range from 70~80%, in color removal the only electrolysis for a treatment of leachate meet the critia of effluent. 2) The highest removal efficiency was represented in pH 7~8. 3) At anode used Al, Fe, Stainless the removal efficiency of CODcr and color was high in order of Fe, Al, stainless, in considering the settled ability of reaction product in economic or after electro coagulation the removal efficiency was highest when anode was the Fe electrode. 4) In this study conditions for removed both CODcr and Color ar the same time represented thar anode was used Fe, electrode-distance was 2cm and reaction time was 40min in 8volts.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.3
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• pp.215-222
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• 2017

In order to evaluate a stress state of concrete according to the change of tensile force of prestressed beam, improved nonlinear resonant ultrasonic spectroscopy(NRUS) method is proposed. This technique is advantageous to evaluate the stress state in initial state because the method shows much higher sensitivity than existing linear ultrasonic methods. The NRUS technique measure a nonlinearity parameter, which is calculated from the resonant frequency shift of ultrasonic wave related to the medium state, and the result is also closely related to the stress state of concrete. In this study, the nonlinearity parameter was measured with the change of tensile force to verify the close relationship between the two factors, and the effect of repetitive load cycle on the change of nonlinearity parameter was analyzed. In addition, sensitivity comparison with the linear ultrasonic pulse velocity method was performed. Through the experimental results, the possibility of NRUS technique for the evaluation of stress state in prestressed beam was confirmed.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.6
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• pp.581-587
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• 2010

In this study, we investigated the effect of the simplification for low frequency region in Head-Related Transfer Function(HRTF) on the sound localization. For this purpose, HRTF was measured and analyzed. The result in the standard deviation of HRTF showed that the directional dependence of low frequency was smaller than that of high frequency region, which means the possibility of simplification in the low frequency region. Simplification was performed by flattening of the low frequency amplitude characteristics with the insertion of the high-pass filter, whose cutoff frequency is given by boundary frequency. Auditory experiments were performed to evaluate the simplified HRTF. The result showed that direction perception was not influenced by the simplification of the frequency characteristics of HRTF for the error of sound localization. The rate of confusion for the front and back was not affected by the simplification of the frequency characteristics within 1kHz of HRTF. Finally, we made it clear that the sound localization was not affected by the simplification of frequency characteristics of HRTF within 1kHz. The result is expected to be utilized to reduce the size of speech information with no deterioration of the directional characteristics of the speech signal.