• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.107-109
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• 2022

본 논문은 건설구조물 안전의 가장 중요한 요소 중 하나인 콘크리트 압축강도 안정성을 확보하기 위한 시스템으로, 콘크리트 구조물을 만들 재료인 레미콘의 수분 감소율에 따른 압축강도 감소 리스크를 관리할 수 있는 모델을 제시하였다. 동일한 물,시멘트비(W/C)로 생산된 레미콘은 현장타설시까지 교통환경으로 인한 도착시간 지연 및 강우, 강설 등 외부적인 요건으로 감수율이 발생하는 리스크가 발생한다. 이로 인해 콘크리트의 압축강도가 저감하는 중대한 문제가 발생한다. 본 연구에서 제시한 알고리즘을 이용하여 현장 타설전 콘크리트 시료의 함수율을 측정하여 감수율이 발생한 제품 발견시, 실시간으로 Operator로 GCM 기반의 Push Alarm을 전송하여 감수율이 반영된 제품을 제공함으로써 구조물의 안전성을 확보할 수 있는 시스템을 모델링하였다. 본 연구는 기존시스템의 문제점을 실시간으로 개선할 수 있는 것으로 건설현장의 구조물 안정성 확보에 효과가 클 것으로 기대된다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.1
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• pp.37-50
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• 2001

Recently, as tunnel structure is getting old, many deformations and defects have been occurred. As tunnel has the characteristics of underground structure, the estimation of the cause of deformation is very difficult. Then, it is necessary to investigate the state of tunnel lining and to estimate the deformation cause and safety for tunnel. In this study, inspection and diagnosis system for effective maintenance in tunnel was researched. Firstly, non-destructive techniques such as GPR (ground penetrating radar), impact echo test, and infrared thermal techniques were applied to tunnel lining inspection. Tunnel lining analysis system was developed to analyze the stability of tunnel. And, tunnel soundness evaluation system was developed to find the probable causes and indicate the method for repair and reinforcement for tunnel.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.353-356
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• 2008

This study was performed to estimate the dynamic behavior for Bi Prestressed Concrete Girder(Bicon girder) which could introduce effectively prestressed forces into concrete girders. Dynamic behavior of PSC girder must be verified because it becomes not only slim but also long and a railway bridge which loaded regularly has risk of resonance especially. Forced vibration test using a vibration machine was executed for 20m railway bridge girder specimen to acquire dynamic characteristics(natural frequency, damping ratio) and test results showed the natural frequency of 6.632Hz and the damping ratio of 1.43%

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.162-166
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• 2006

기존의 Ni PPF를 대신하여 새롭게 Cu-Sn 합금을 barrier층으로 적용한 PPF를 제조하여, 그 제반 특성들을 조사하였다. Cu-Sn 합금도금층은 기존의 Ni PPF와 마찬가지로 반도체 substrate로서 지녀야 할 열적 안정성을 충분히 확보할 수 있음을 알 수 있었다. 또한 기지층 및 보호층과의 계면간 밀착성이 Ni PPF보다 더 우수했으며, 미세한 결정립들이 균일하게 분포한 도금층 구조를 나타내어, 이들이 Ni PPF보다 구조적으로 더욱 안정할 것임을 예상할 수 있었다. 한편 강자성 거동을 보이는 Ni PPF와는 달리 Cu-Sn PPF는 완벽한 상자성 특성을 보여, 점차 고집적, 고밀도화 되어가는 반도체 패키지의 동작중 발생할 발열 및 신호간섭의 위험이 원천적으로 제거될 수 있음을 보였으며, solderability, bondability 등의 field 특성 또한 Ni PPF와 거의 비슷함을 알 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.511-519
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• 2021

Slewing bearing is applied to the transmission of rotational power of the body and turret in a special vehicle for anti-aircraft weapons that overcomes the enemy flight system approaching at low altitudes with rapid response fire. When the turret load and impact load generated when shooting are combined in performing the combat mission of a special vehicle, structural stability must be secured to achieve a successful function. Among the components of the slewing bearing, the stability of the components against the complex loads acting by the turret drive and shooting was evaluated by considering the shape and material characteristics of the ring-gear, roller, and wire-race. As a research method for stability evaluation, based on engineering theory, the strength characteristics of the components were examined by numerical calculations. Finite element analysis was performed on components using the ANSYS analysis program. The results of theoretical analysis and the results of finite element analysis were very similar. A structural stability evaluation for the slewing bearing, which was performed mainly on the analysis, confirmed that the design strength of the slewing bearing determined in the preliminary design in the early stage of localization development was sufficient.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.72-79
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• 1996

The effect of controllers-Exciter, Power System Stabilizer, and Static Var Compensator-in one machine infinite bus system is investigated in this paper. The structure of generator state matrix with controllers is represented, while the Static Var Compensator is installed in generator terminal bus. Eigen-value analysis is performed and the effects of controllers to the dominant eigenvalue in one machine infinite bus system are represented by first order eigenvalue sensitivity coefficients while the operating conditions of the system are varied. Optimization of controller parameters using first order eigenvalue sensitivity coefficients is performed by the Simplex Method. It is proved that exciter control is the most efficient method to improve stability of the system and the effect of Static Var Compensator is small, in the case of one machine infinite bus system.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.4
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• pp.113-122
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• 2013

In this study, the traditional structure of the impact on the stability analysis. Korean traditional landscape architecture column space of stonework stable composition as the foundation of the fence for a long time been known to fall down and not maintained. The destination of research Ohgokmun Damyang Soswaewon fence which is in harmony with nature is one of the traditional structures that affect its shape without being kept so far came true. This includes our ancestral wisdom and that wisdom can guess guesswork. But I let the traditional reproduction incidence structures frequently. This deviation from the traditional method of construction application of shorthand stand. Thus, the subject of this study, the factors that do not fall down fences Ohgokmun solution is to indirectly gain the weak. In addition, epidemiological studies and the methods of calculation of the inferred physical examination, the results of the analysis were derived through the following. First, the internal factors of the fence Ohgokmun constituting the structural member and the coupling of the scheme. 1) based on stable ground. Greater role in the country rock The fact that the settlement will have no symptoms. 2) to minimize the friction caused by hydrological water to remove the two-pronged process through stone work building form and menu sustaining power in hydrology and flooding made against the bypass channel. 3) due to the load bearing capacity and durability to withstand the strength of the material and the construction of structures in the form of a dispersion of power between each individual to maximize the process of getting traction was applied. Second, external factors Ohgokmun fence the results obtained through the calculation of the dynamics of repair, is greatly affected by the wind and the water gate of the fence, but the action of the structural stability of the lack of power that hurt enough conclusion. In this study, the results of the structure of internal and external influence as well through the structure can be viewed as composed consisting. However, over the next follow-up in terms of climate and environmental factors due to the fact that the fall might.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1568_1569
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• 2009

RFID 수동 태그의 동작 원리를 이용하여 USN/WBAN 센서 노드 시스템에 적용 가능한 웨이크 업 회로를 설계하였다. 웨이크 업회로 구성은 크게 전압 체배기, 복조기, 상태기계로 구성되었다. 상태 기계에 동작 가능한 전압을 공급하기 위해 전압 체배기는 문턱 전압 제거 방식을 적용한 구조를 사용하였고, 복조기 회로로는 AM 복조기로 구조가 간단한 포락선 검파기 방식을 사용하였다. 전압 체배기에 높은 전압이 인가될 경우 회로가 파괴되는 것을 막기 위해 제한 회로를 구성하여 최대 전압을 2.1V로 제한하였다. 또한 복조기에서는 안정적인 데이터 복조를 위해 비교기의 기준전압을 입력신호의 평균값을 사용한 슈미트 트리거 비교기를 사용하여 안정적으로 데이터를 추출하였다. 삼성 0.18um CMOS 공정을 이용하여 설계하였고, 측정 결과 전압 체배기의 체배 전압은 2.07~1.76V까지 체배 되는 것을 확인하였고, 복조기의 데이터 복조 역시 약 4M의 거리까지 데이터를 복조함을 확인하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.170-175
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• 2008

모든 Network는 대역폭의 한계성을 갖고 있다. Overlay 구조의 Network 또한 예외는 아니다. 이러한 Network 대역폭 자원의 한계성은 Network를 이용한 많은 통신에 있어서 심한 Traffic 을 형성하고 그로 인한 낮은 대역폭을 제공해준다. 이에 대한 해결책으로 Multi-Hour Ability 를 적용할 수 있다. 우리가 살아가는 환경은 서로 다른 시간대가 존재하며, 그로 인한 생활패턴에 따라 Network를 이용하는 정도 또한 시간대별로 다르다. 이 논문에서는 라우팅이 자유로운 Overlay Network를 통해 Multi-Hour Ability를 적용하여 Network에 발생한 Traffic 을 완화시키고, 잉여 대역폭을 효과적으로 사용하며, 보다 안정적인 대역폭 확보를 통해 성능 향상을 할 수 있다는 것을 보인다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.229-232
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• 2009

DC-shift phenomenon can be observed in Hybrid rocket combustion. This phenomenon makes performance drop which is structure problem or reduce thrust. Understanding of DC-shift phenomenon, the conditions of the hybrid rocket combustion stability can be found. In this paper, the condition of DC-shift was found and made by using acoustic mode and vortex shedding frequency. The conditions of stable combustion was defined from the experimental study of DC-shift phenomenon.