• Structural Engineering and Mechanics
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• 제72권4호
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• pp.525-540
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• 2019

The purpose of the present work was to study the dynamic instability of a three-layered, symmetric sandwich beam subjected to a periodic axial load resting on nonlinear elastic foundation. A higher-order theory was used for analysis of sandwich beams with soft core on elastic foundations. In the higher-order theory, the Reddy's third-order theory was used for the face sheets and quadratic and cubic functions were assumed for transverse and in-plane displacements of the core, respectively. The elastic foundation was modeled as nonlinear's type. The dynamic instability regions and free vibration were investigated for simply supported conditions by Bolotin's method. The results showed that the responses of the dynamic instability of the system were influenced by the excitation frequency, the coefficients of foundation, the core thickness, the dynamic and static load factor. Comparison of the present results with the published results in the literature for the special case confirmed the accuracy of the proposed theory.

• 디지털융복합연구
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• 제12권4호
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• pp.259-264
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• 2014

최근 센서 기술의 발달로 인하여 체내삽입장치를 부착한 환자가 언제, 어디서나 의료 서비스를 받을 수 있는 환경으로 변화하고 있다. 그러나, 체내삽입장치를 부착한 환자의 생체정보가 병원관계자(의사, 간호사, 약사 등)에게 전달할 때, 환자의 정보가 제 3자에게 쉽게 노출되어 악용될 수 있는 문제점이 발생되고 있다. 본 논문에서는 제3자가 환자로 위장하여 병원관계자로부터 환자 정보를 쉽게 획득할 수 없도록 유헬스케어 서비스 센터로부터 환자의 위임장을 병원관계자가 전달받는 위임장 기반의 서명 인증 프로토콜을 제안한다. 제안 프로토콜은 환자의 민감한 정보를 제 3자에게 노출시키지 않도록 환자의 민감한 정보를 유헬스케어 서비스 센터와 환자가 생성한 랜덤수로 해쉬한 서명키로 환자의 민감한 정보를 암호화한다. 또한 제 3자로부터 환자 정보가 불법적으로 악용되는 것을 예방하기 위해서 환자와 병원관계자 사이의 동기화를 유지함으로써 환자의 생체 정보 유출을 예방할 수 있다.

• Journal of Acupuncture Research
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• 제20권6호
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• pp.63-79
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• 2003

Objective: It makes a through study on the popularization and usefulness paln of Moxa Combustion, therefore popularizing practical use of that. Methods: It was based on the established treatises and books, in order to studying about the literature of Moxa Combustion Results & Conclusions: It makes a through study on the whole of Moxa Combustion, the results as follows. 1. We explained(illustrated) the origin, history, classification and mechanism(effect) of Moxa Combustion 2. The study of standardization plan of Moxa Combustion for popularization - The thermal stimulation of Moxa Combustion was decided the characteristic pattern of combustion temperature by moxa burning and that makes a measure to grasp the effective action of Moxa Combustion upon human body. Thereupon it is necessary to continue further studies by analysing the characteristic pattern of combustion temperature by moxa burning and there clinical effects in practice. 3. The usefulness of Moxa Combustion - The therapeutic effect of Moxa Combustion are hematopoiesis(increase the blood), analgesic function, increase the immunity, antioxidant activity, diuretic action, control of hormone(endocrine gland), supression of carcinogenesis, increase the self involution(natural healing), decrease of GOT/GPT, Glucose, Cholesterol level.

• 대한예방한의학회지
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• 제9권2호
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• pp.93-106
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• 2005

A survey was performed for 2 weeks in October 2004 in order to examine the effects and changes of far infrared and anion of office workers aged 40 and older before and after wearing the underwear. In the survey, questionnaires and photoplethysmography were used to measure the difference between the two tests conducted with one week interval. The findings could be summed up as follows: 1. There was no statistically significant difference in changes of vascular aging points and photoplethysmogram wave form before and after wearing the far infrared and anion underwear but the points showed the increasing tendency(p>0.05). 2. A statistically significant difference was confirmed since the total points of each item in the questionnaires increased after wearing the underwear(p<0.001). 3. In connection with the systemic symptoms, a significant difference was found with increased points in all items except for no. 6 after wearing the underwear(p<0.05). 4. With regard to the difference before and after wearing the underwear depending on the Kidney symptoms, there was a significant difference with increased points in all items except for item no. 1 after wearing the underwear(p<0.05). In conclusion, to put on the underwear with effect of far infrared and anion is believed to smooth metabolism and blood circulation, contributing by thus to promoting health and preventing disease. Further studies with wider sampling of subjects are requested to diversify and refine the findings from this sectional study.

• 항공우주정책ㆍ법학회지
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• 제21권1호
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• pp.65-95
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• 2006

항공기에 의하여 발생된 지상의 손해에 대한 책임이 국제적 수준으로 규정되어야 함은 필수적이다. 그러나 1952년의 "외국항공기에 의하여 발생된 지상 제3자의 손해에 관한 로마협약" 및 1978년의 "몬트리올 의정서"는 소수의 국가들이 그것을 비준하였기 때문에 전세계적으로 중요한 영향을 가지지 못하였다. 그리하여 세계민간항공기구 사무국은 2002년에 로마협약의 현대화를 위한 협약초안을 작성하였으며, 특별그룹은 현재까지 협약초안을 검토해오고 있다. 한편 협약초안은 항공기 운항자의 책임체제와 지상 제3자의 손해에 대한 위험의 부보가능성에 관한 주요한 문제들을 포함하고 있다. 한 국가의 항공운송 부문의 보호 뿐만 아니라 피해자의 신속한 회복을 용이하게 하기 위하여 로마협약의 현대화 작업은 계속되어야 하며 신협약은 가까운 장래에 마무리되어야 할 것이다.

• 한국가스학회지
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• 제4권3호
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• pp.59-64
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• 2000

배관에 가해지는 충격을 실시간으로 모니터링하고, 충격위치를 산출 할 수 있는 모니터링 시스템을 무선데이타 통신을 이용하여 개발하였고, 마산만 해저배관에 현장적용 후 충격실험을 통하여 유용성을 검증하였다. 실험에 사용된 배관은 총 길이 1365m, 운용압력 8.6kgf/cm^2$$, 직경 12inch인 실제 운용중인 해저가스배관을 사용하였다. 충격실험에서 충격위치 계산오차는 배관내에서 충격음파 속도의 $1\%$정도의 거리였다.

• 한국중재학회지:중재연구
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• 제28권4호
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• pp.153-172
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• 2018

In solving international commercial disputes, arbitration has a unique advantage. Therefore, when most parties sign a charter party, they contain arbitration clauses. Whether the arbitration clause in the charter party can be effectively incorporated into the bill of lading and bind to the third party-bill holder becomes an important issue. Based on the problem above, this paper compares the arbitration system between Korea and China, and discusses the composition of the Chinese Maritime Court and the Chinese court's adjudication of arbitration for foreign countries, which are recognized and enforced in China. What is most important in this study is observing the Chinese case from the beginning of 2000 to the present in order to rule whether the Chinese court can effectively incorporate the arbitration clause in the charter party into the bill of lading, as well as whether it constitutes an effective binding force for third parties and changes in standard of recognition. Finally, through comparative analysis, the study concludes that in China, the arbitration clause in the charter party can be effectively incorporated into the bill of lading, and that the conditions for the third parties can be effectively restrained. There must be several points to be noted when recording the bill of lading. This would then help reduce the legal risks and promote the sustainable development of international transactions.

• 한국수자원학회논문집
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• 제41권2호
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• pp.229-239
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• 2008

본 연구는 3차 하천에 대하여 유도되었던 지형형태학적순간단위도(GIUH)를 4차 하천유역까지 확장하여 다양한 유역에 적용할 수 있도록 하였다. $2{\sim}4$차 하천에 대한 GIUH를 비교하였으며 유역의 지형매개변수가 동일할 경우 하천차수를 높게 가정할수록 단위도의 첨두유출량은 작아지고 첨두발생시간은 늦어지는 경향을 확인할 수 있었다. GIUH의 적용을 위해서는 면적비와 분기비 등 지형매개변수를 사용하여 초기확률을 산정하는데, 이때 지형매개변수가 가지는 오차 때문에 특정 유역에서 초기확률이 음수가 되는 문제가 발생하며 단위도의 전반부에서 유출량이 음의 값을 가지기도 한다. 이러한 문제점을 해결하기 위하여 본 연구에서는 ArcVeiw GIS 3.2를 사용하여 전체면적에 대한 직접유출면적의 비율로 초기확률을 계산하였다. 제안된 방법을 적용하여 상안미, 병천, 산계 등의 유역에서 $2{\sim}4$차 하천에 대한 순간단위도를 산정하여 본 결과, 위의 문제점을 해결할 수 있었다.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1227-1238
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• 2000

This study examines the effects of the discretization schemes on numerical solutions of viscoelastic fluid flows. For this purpose, a temporally evolving mixing layer, a two-dimensional vortex pair interacting with a wall, and a turbulent channel flow are selected as the test cases. We adopt a fourth-order compact scheme (COM4) for polymeric stress derivatives in the momentum equations. For convective derivatives in the constitutive equations, the first-order upwind difference scheme (UD) and artificial diffusion scheme (AD), which are commonly used in the literature, show most stable and smooth solutions even for highly extensional flows. However, the stress fields are smeared too much and the flow fields are quite different from those obtained by higher-order upwind difference schemes for the same flow parameters. Among higher-order upwind difference schemes, a third-order compact upwind difference scheme (CUD3) shows most stable and accurate solutions. Therefore, a combination of CUD3 for the convective derivatives in the constitutive equations and COM4 for the polymeric stress derivatives in the momentum equations is recommended to be used for numerical simulation of highly extensional flows.

• Structural Engineering and Mechanics
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• 제68권3호
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• pp.325-334
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• 2018

The Nonlinear dynamic response of a sandwich plate subjected to the low velocity impact is theoretically and experimentally investigated. The Hertz law between the impactor and the plate is taken into account. Using the Extended High Order Sandwich Panel Theory (EHSAPT) and the Ritz energy method, the governing equations are derived. The skins follow the Third order shear deformation theory (TSDT) that has hitherto not reported in conventional EHSAPT. Besides, the three dimensional elasticity is used for the core. The nonlinear Von Karman relations for strains of skins and the core are adopted. Time domain solution of such equations is extracted by means of the well-known fourth-order Runge-Kutta method. The effects of core-to-skin thickness ratio, initial velocity of the impactor, the impactor mass and position of the impactor are studied in detail. It is found that these parameters play significant role in the impact force and dynamic response of the sandwich plate. Finally, some low velocity impact tests have been carried out by Drop Hammer Testing Machine. The results are compared with experimental data acquired by impact testing on sandwich plates as well as the results of finite element simulation.