• 한국가스학회지
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• 제23권1호
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• pp.1-11
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• 2019

한국 정부는 액화 천연가스를 대체하는 에너지원으로서 러시아의 파이프라인 천연가스 도입을 1990년대 이후부터 지속적으로 모색해오고 있다. 이러한 동북아 에너지 협력에 대한 논의가 현실 정치뿐만 아니라 학술적인 차원에서도 다양하게 진행되고 있지만, 기존의 선행연구들은 협력의 당위성만을 제시하고 있을 뿐이지 이론적 분석틀이 미약하다는 한계를 지니고 있다. 이에 본 논문에서는 경제통합론이라는 이론적 자원을 바탕으로 에너지협력의 동기 조건 단계를 분석하고자 한다. 연구 결과 동북아 천연가스 협력과 관련해서는 경제적 동기만이 유일하기는 하지만, 실질적인 기대이익뿐만 아니라 경제구조의 보완성과 정책목표의 수렴성이라는 조건들이 갖추어진 것으로 파악되었다. 결론적으로 동북아에서 높은 수준의 에너지 협력은 어렵겠지만 특혜무역협정 수준의 초보적인 천연가스 협력이 가능하다는 전망이 제시될 수 있었다.

• 플랜트 저널
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• 제14권1호
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• pp.34-41
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• 2018

과거의 학문은 기초의 시대이며, 현재의 학문은 융합의 시대이며, 미래의 학문은 통합의 시대이다. 학문 통합의 필수 조건은 모든 학문이 서로 동등해야 한다는 것이며, 오직 자연법칙으로부터 파생된 법칙만이 통합의 동등성을 구현할 수 있을 것이다. 변화를 일으킬 수 있는 능력을 에너지로 정의할 것을 제안한다. 만물은 변화하며 그 변화에는 방향성이 필히 존재하므로, 변화와 방향성은 모든 학문에 동등하게 적용된다. 통합학문의 제 0 법칙은 존재의 법칙, 제 1 법칙은 변화 보존의 법칙, 제 2 법칙은 무효변화 증가의 법칙, 제 3 법칙은 지침의 법칙, 그리고 제 4 법칙은 융합의 법칙이다. 위 법칙들은 열역학의 자연법칙과 매우 유사함을 볼 수 있다. 통합학문 5 대 법칙의 최종 목표는 지구상에서 자연, 인간, 인공지능 개체들이 서로 협력하여 발전하는 공동체의 구현이다.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4570-4575
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• 2023

Noise and Radio-frequency interference or RFI causes a significant restriction on the Free induction Decay or FID signal detection of the Nuclear Quadrupole Resonance procedure. Therefore, using this method in non-isolated environments such as industry and ports requires extraordinary measures. For this purpose, noise reduction algorithms and increasing signal-to-noise-and-interference ratio or SNIR have been used. In this research, sodium nitrite has been used as a sample and algorithms have been tested in a non-isolated environment. The resonant frequencies for the 150 g of test sample were measured at 303 K at about 1 MHz and 3.4 MHz. The main novelty in this study was, (1) using two types of antennas in the receiver to improve adaptive noise and interference cancellation, (2) using a separate helical antenna in the transmitter to eliminate the duplexer, (3) estimating the noise before sending the pulse to calculate the weighting factors and reduce the noise by adaptive noise cancellation, (3) reject the interference by blanking algorithm, (4) pulse integration in the frequency domain to increase the SNR, and (5) increasing the detection speed by new pulse integration technique. By interference rejection and noise cancellation, the SNIR is improved to 9.24 dB at 1 MHz and to 7.28 dB at 3.4 MHz, and by pulse integration 44.8 dB FID signal amplification is achieved, and the FID signals are detected at 1.057 MHz and 3.402 MHz at room temperature.

• 한국디지털건축인테리어학회논문집
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• 제10권3호
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• pp.79-86
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• 2010

From the research which sees the building which uses a natural control method with ecological architecture, continuity tried to divide the building which uses a physical control method with sustainable architecture. Ecological architecture analyzes the microclimate of the area and applies mining and natural ventilation leads and that the interior environment controls, the condition of the site actively and there is a possibility of seeing. Also sustainable architecture which is possible to lead and recycling and reuse of the resources and energy cyclic process of the construction resources to lead and the interior environment to control. Therefore the case where the facility system and structural system become integrated design organically in natural circulating method is many. Specially the sunshade system and double skin system are combined and structural system of the building and there is a possibility of having the envelope which form is feature. Today the buildings lead and the system integration process where the integral parts are systematic is demanded the interior environment which and an external form and that, they make they are there is a possibility of seeing. the environmental building which hits joins in with natural control method and the structure and facility system are integrated and has the tendency which is developed and there is a possibility of saying that a meaning with the alternative construction will be able to reduce the resources and an energy.

• 대한기계학회논문집
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• 제13권3호
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• pp.317-322
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• 1989

본 연구에서는 Liu의 매트릭스를 강소성 유한요소법에 도입하여 통상의 소성가공 공정중에 있는 피가공물의 3차원 변형을 실용적인 수준에서 해석 가능케 하는 강소성 유한요소법을 도입하여 통상의 소성가공 공정중에 있는 피가공물의 3차원 변형을 실용적인 수준에서 해석 가능케 하는 강소성 유한요소법을 제안하고 실례를 통하여 제안한수법에 의하여 얻어진 해의 안정성과 계산효율을 검토한다.

• 전기학회논문지
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• 제59권11호
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• pp.1971-1979
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• 2010

As a result of increasing environmental concern, the penetration of renewable power on power systems is now increasing. Wind energy can be considered as the most economical energy sources to generate electricity without depletion of fossil fuel. To devise adequate control strategies for wind farm, time domain simulation analysis needs to be performed. This presents a continuation time integration (CTI)-based time domain simulation algorithm for wind farm with doubly fed asynchronous generator (DFAG) connected to the external power systems. This paper depicts how to time trajectories are traced using CTI-based time domain simulation. Also this paper describes the possibilities of hierachical control for wind farm output limitation, and the coordinated control has been designed by hierarchical control structured from central control level to wind farm control board and to an individual wind turbine level. Finally it shows an illustrative example of time domain simulation result with two test systems through case study.

• Journal of Mechanical Science and Technology
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• 제19권12호
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• pp.2187-2196
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• 2005

In this paper, the stiffness and the mass matrices for the in-plane motion of a thin circular beam element are derived respectively from the strain energy and the kinetic energy by using the natural shape functions of the exact in-plane displacements which are obtained from an integration of the differential equations of a thin circular beam element in static equilibrium. The matrices are formulated in the local polar coordinate system and in the global Cartesian coordinate system with the effects of shear deformation and rotary inertia. Some numerical examples are performed to verify the element formulation and its analysis capability. The comparison of the FEM results with the theoretical ones shows that the element can describe quite efficiently and accurately the in-plane motion of thin circular beams. The stiffness and the mass matrices with respect to the coefficient vector of shape functions are presented in appendix to be utilized directly in applications without any numerical integration for their formulation.

• Architectural research
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• 제20권4호
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• pp.121-128
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• 2018

Given the barriers to implement green building rating systems, Building Information Modeling (BIM) was suggested as an effective solution integrating information into one model and saving substantial time to facilitate certification process. Synergies between BIM and Leadership in Energy and Environment Design (LEED), the most widely used rating system, have been researched for a few decades. This paper demonstrates literature review about the development of integration between BIM and LEED. The research focuses on synergies between BIM and Green Standard for Energy & Environmental Design (G-SEED) in Korea, as one of important strategies to mitigate greenhouse gas emission. The research compares LEED and G-SEED related items based on evaluation contents. The result manifests G-SEED and LEED share many common items in different degrees. Therefore, it is entirely possible for G-SEED and BIM to adapt same developing mode of LEED and BIM. Moreover, the study measures the potential of BIM in application process of G-SEED certification by investigation of credits in LEED and G-SEED can be earned by BIM. The results of paper indicate the documentation support LEED and G-SEED may be prepared directly, semi-directly and indirectly via sustainability analyses software in BIM.

• Advances in Computational Design
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• 제8권3호
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• pp.237-253
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• 2023

Torque ripple content and variable switching frequency operation of conventional direct torque control (DTC) are reduced by the integration of space vector modulation (SVM) into DTC. Integration of space vector modulation to conventional direct torque control known as SVM-DTC. It had been more frequently used method in renewable energy and machine drive systems. In this paper, SVM-DTC is used to control the rotor side converter (RSC) of a wind driven doubly-fed induction generator (DFIG) because of its advantages such as reduction of torque ripples and constant switching frequency operation. However, flux and torque ripples are still dominant due to distorted current waveforms at different operations of the wind turbine. Therefore, to smoothen the torque profile a Neural Network Controller (NNC) based SVM-DTC has been proposed by replacing the PI controller in the speed control loop of the wind turbine controller. Also, stability analysis and simulation study of DFIG using process reaction curve method (RRCM) are presented. Validation of simulation study in MATLAB/SIMULINK environment of proposed wind driven DFIG system has been performed by laboratory developed prototype model. The proposed NNC based SVM-DTC yields superior torque response and ripple reduction compared to other methods.

• 한국정밀공학회지
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• 제14권12호
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• pp.17-23
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• 1997

A 3-D vision system is developed to evaluate blanks' line up and monitor gap and thickness difference between blanks in tailored blank welding system. A structured lighting method is used for 3-D vision recognition. Images of sheared portion in blanks are irregular according to roughness of blank surface, shape of sheared geometry and blurring. It is difficult to get accurate and reliable informations in the case of using binary image processing or contour detection techniques in real time for such images. We propoe a new energy integration method robust to blurring and changes of illumination. The method is computationally simple, and uses feature restoration concept, different to another digital image restoration methods which aim image itself restoration and may be used in conventional applications using structured line lighting technique. Experimental results show this system measuring repeatability is .+-. pixel for gap and thickness difference in static and dynamic tests. The data are expected to be useful for preview gap control.