• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.86-86
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• 2017

마늘파종기는 파종기구동부와 파종후 파종홀의 복토역할을 하는 파종기롤러, 지면과의 마찰을 통해 바퀴의 회전토크가 발생하며 발생된 토크는 파종기 내부 동력으로 전달되어 전체 파종시스템(배종, 호퍼캠, 파종부)을 동작 시키는 기능을 수행하는 파종바퀴, 마늘종구를 한알씩 집어올려 중간이송컵으로 이송하는 자세교정컵이 포함된 배종부와 자세교정컵에서 낙하된 마늘종구를 땅속으로 파종하는 파종장치로 구성된다. 배종율 95%, 2립 배종률 5% 성능을 확보할 수 있는 기술이 개발될 경우 세계적으로도 독보적인 기술 우위를 확보할 수 있다. 이와 같은 기본적인 기능을 구현할 수 있는 컨셉모델에 대한 설계를 수행하여 시제품개발 전 기구해석과 구조해석 등을 위한 기본설계를 수행하였다. 배종율 95% 이상을 확보하기 위해서는 기존의 현장경험의 의한 설계 방식으로는 한계가 있기 때문에 시뮬레이션 및 분석 개발이 필요한데, 프레임은 고정밀 마늘종구 배종부 장착을 위한 기본 구조물로써 작동시 동력을 얻기 위한 바퀴와 연계가 되도록 설계되었으며, 호퍼는 배종 수행을 위해 마늘을 저장해 두는 통으로써 배종부와 연결된다. 배종부의 배종판이 회전함에 따라서 배종판의 홈이 호퍼 내로 들어갔다 나오면서 마늘을 집게되며, 동력 전달부는 배종판을 회전시켜주고, 회전 속도 조절을 가능하게 한다. 파종부는 배종부에서 중간컵을 통해 하나씩 공급해준 마늘을 땅에 심는 부분으로서. 프레임의 바퀴 회전과 연동되어 회전하고 설계하였다. 배종판에서 중간컵으로 이송된 마늘을 파종부의 파종컵에 받아 회전하면서 땅속에 파종컵이 묻히면 파종컵이 열리면서 땅속에 마늘을 심는 원리이다. 조간조정은 7조식의 경우 초기설치시 고정되도록 설계되었으며 농촌진흥청 기계화 표준재배안에 따라 의성마늘 기준 $14{\times}14cm$(조간${\times}$주간)를 기준으로 개발하였다. 조간조정은 기계가 설치되면 조정하기 어려우므로 14cm로 설계하였으며, 주간조정은 원형배종장치의 구동기어부의 속도비로 간격을 조정할 수 있도록 기어장치를 설계하였다. 주간조정은 13에서 18cm의 범위에서 작동하도록 설계되었으며, 필요에 따라 간격조절이 가능함. 마늘은 그 크기가 다르고, 형상도 다르기 때문에 종자에 따른 개별적인 파종기술들이 개발되어야하기 때문에 개발 기간이 오래 걸리고, 수익에 비하여 개발비가 과다하게 요구되는 실정인데 축적된 시뮬레이션 툴을 이용한 파종기 분석 기술을 확보할 경우 다른 파종기의 연구 개발에도 크게 도움이 될 것으로 기대되며, 생육측정 실험과 동역학 해석 툴 RecurDyn을 통해 파종기의 기구학적 분석을 통한 설계반영 인자를 도출할 계획이다.

• Journal of the Korean Society of Floral Art and Design
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• no.41
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• pp.133-153
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• 2019

This study is about the development and creation of the public installation to enhance the contact chances with plants for the city dwellers who are living in the environment of limited green space. The researcher tried to create a floral art work at an island type bus stop on the central bus only lane, where the passers-by can enjoy the contact with plants for a second on that crowded space. The researcher made the study of various related cased world-widely and existing island type bus stop on the central bus only lane. The researcher also made pre-creation study of applicable forms and elements, and developed the prototype of the installation on the base of that study. Therefore the researcher created 1 installable screen type floral art work offering abundant contact experience to the viewers which has multiple shelves in the vertical frame to fit and be substituted by the designated wall unit of the island type bus stop structure. Also the researcher developed the prototypes of 2 small interior pieces. The meaning of this study can be found in the contribution of increasing visual experiencing rate of green space and chances of experiencing plants to create positive psychological, emotional effects by developing floral art works to be installed at crowded urban public space.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.1
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• pp.49-56
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• 2024

An automated dynamic structural analysis module stands as a crucial element within a structural integrated mitigation system. This module must deliver prompt real-time responses to enable timely actions, such as evacuation or warnings, in response to the severity posed by the structural system. The finite element method, a widely adopted approximate structural analysis approach globally, owes its popularity in part to its user-friendly nature. However, the computational efficiency and accuracy of results depend on the user-provided finite element mesh, with the number of elements and their quality playing pivotal roles. This paper introduces a computationally efficient adaptive mesh generation scheme that optimally combines the h-method of node movement and the r-method of element division for mesh refinement. Adaptive mesh generation schemes automatically create finite element meshes, and in this case, representative strain values for a given mesh are employed for error estimates. When applied to dynamic problems analyzed in the time domain, meshes need to be modified at each time step, considering a few hundred or thousand steps. The algorithm's specifics are demonstrated through a standard cantilever beam example subjected to a concentrated load at the free end. Additionally, a portal frame example showcases the generation of various robust meshes. These examples illustrate the adaptive algorithm's capability to produce robust meshes, ensuring reasonable accuracy and efficient computing time. Moreover, the study highlights the potential for the scheme's effective application in complex structural dynamic problems, such as those subjected to seismic or erratic wind loads. It also emphasizes its suitability for general nonlinear analysis problems, establishing the versatility and reliability of the proposed adaptive mesh generation scheme.

• Journal of Korean Society of Steel Construction
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• v.12 no.5 s.48
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• pp.495-502
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• 2000

In this study, the wind tunnel test for Kwangju World Cup Stadium with long span roof was carried out and its results were considered in the two roofs: one is the case of one roof, and the other is the case of two roofs which are identical. In this experiment, a 1/400-scale model was used. As a result of measuring wind pressure in the case of one roof and then two, when two roofs are set up, wind load for structural frame decreases by 35%, compared to that of one roof. These results show that the current criteria for wind loadings, which specify that wind pressure on the roof depends only on the altitude, have limitations for adoption, and a wind tunnel test is essential to design.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.797-803
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• 2010

A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of pre-stressed concrete (PSC) box girder bridges on the Korea high speed railway. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyze accurately and evaluate with in-depth parametric studies for dynamic responses of bridge due to the high speed railway vehicles. Three dimensional frame element is used to model the PSC box girder bridges, simply supported span lengths 40 m. The high-speed railway vehicles (K-TGV) including a locomotive are used as 38-degree of freedom system. Three displacements (vertical, lateral, and longitudinal) as well as three rotational components (pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic analysis by Runge-Kutta method which are able to analyze considering the dynamic impact factors are compared and contrasted. It is proposed as an empirical formula that the impact factors damaged the bridge load-carrying capacities occurs to the bride due to high-speed vehicle.

• Land and Housing Review
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• v.5 no.4
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• pp.305-314
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• 2014

The technology-intensive unit modular method of factory production method is attracting attention by the limit of the labor-intensive and field centered wet construction method. In recent years, the unit modular method has been applied to the construction of schoolhouse and BOQ(bachelor offices' quarters), dormitories, etc. But the modular method still is not used in housing construction by the lack of verification of resident performance and construction cost. Therefore, this study analyzed the economics of modular house to vitalize the constructed residential building by modular method and to develop the modular method. According to the study results, the construction cost of the modular house was analysed more about 6.2% expensive than that of the existing housing. However, if the construction duration of modular house is shortened or the productivity of modular house is increased, the construction cost of modular house will be similar to the that of the existing house.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.249-249
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• 2022

국외에서 산지재해를 예방하기 위해 하천 유사량을 계측하는 기존의 재래식 채집기의 문제점을 보완한 간접계측장치인 하이드로폰의 개발 및 실용화를 위한 연구를 수행하고 있다. 하지만 국내의 경우 유사량을 계측하는 기술 수준은 선진국에 비해 기초단계에 머물러 있다. 이러한 문제를 해결하기 위해 국내에서 사용하기 적합한 간접계측장치를 개발하고자 한다. 간접계측장치인 하이드로폰은 횡단구조물의 끝단에 부착하여 설치하는 형태로 개발하였다. 충돌음향 계측을 위한 센서부는 파이프와 마이크로폰으로 구성하였으며, 구조물에 부착하기 위한 고정프레임과 연결장치로 제작되었다. 설치된 계측장치는 하상에서 이동중인 토사가 파이프에 충돌할 때 발생하는 소음을 계측하며 충돌음은 데이터로거로 취득된다. 계측된 음향 데이터는 정확한 소류사량 추정을 위해 충돌 횟수에 착안한 펄스 분석 방법과 진폭의 시간 적분치에 착안한 음압적분치 방법으로 비교·검토를 수행하였다. 소류사량 추정 관계식의 유의성 분석을 수행한 후 펄스 수 기반 추정 관계식과 음압적분치 기반 추정 관계식을 공급 소류사량과 비교시 각각 29%와 33%의 오차율을 나타내는 것을 확인할 수 있었다. 앞서 선정된 소류사량 추정 관계식의 신뢰성을 확보하기 위해 관계식으로 추정할 수 있는 예측구간 및 95% 신뢰구간을 분석하였으며, 분석 결과 펄스 수 기반 추정 관계식은 92.5%, 음압적분치 기반 추정 관계식은 90.9%로 두 관계식 모두 소류사량을 추정하기에 양호한 수준으로 일치하는 것을 확인할 수 있었다. 향후 추가적인 연구를 수행한다면 수문조사 시 부족했던 유사량 측정분야의 확대에 기여할 수 있을 것으로 예상되며, 이와 관련된 사업 및 기술발전에도 기여할 것으로 기대된다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.204-211
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• 2011

A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of bridge during the passage of high speed railway vehicles. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyse accurately and evaluate with in-depth parametric studies for dynamic responses of various bridge span lengths running KTX railway locomotive up to increasing maximum speed(450km/h). Three dimensional frame element is used to model the simply supported pre-stressed concrete (PSC) box bridges for four span lengths(40~25m). Track irregularity employed as a stationary random process from the given spectral density functions and irregularities of both sides of the track are assumed to have high correlation. The high-speed railway vehicle (KTX) is used as 38-degree of freedom system. Three displacements (Vertical, lateral, and longitudinal) as well as three rotational components (Pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic amplification factors are evaluated by the developed procedure under various traveling conditions, such as track irregularity camber, train speed and ballast. The dynamic analysis such as Newmark-${\beta}$ and Runge-Kutta methods which are able to analyse considering the dynamic impact factors are compared and contrasted.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.35-42
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• 2020

Torsional behavior due to the plane irregularities of the piloti building can cause excessive story drift in the torsionally outermost column, which can lead to shear failure of the column. As a seismic retrofit method that can control the torsional behavior of the piloti building, the expansion of RC wall, steel frame or steel brace may be used, but such methods may hinder the openness of the piloti floor. Therefore, in this study, linear dynamic analysis and nonlinear static analysis for piloti buildings retrofitted by knee brace were performed, and seismic performance evaluation and torsion control effect of knee brace were analyzed. The results showed that the shear force of the column increased when the piloti building retrofitted by knee brace, but it was effective in controlling the torsional deformation. In case of retrofit between knee brace and column by 30°, the shear force of the column increased less than that of 60°, and the lateral displacement of column was decreased in the order of □, ◯ and Ｈ in cross-section.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.60-67
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• 2021

In lately, it's been developed and used a system of using deck plates as formwork in order to solve various problems caused by conventional formwork system. This system is more economical and has higher constructability than the conventional system by permanently embedding most of deck plates into the members. However, for this kind of embedded deck plates formwork system, it's been reported that it is difficult to verify filling of concrete in members like beams with narrow width and complicated rebar arrangement. In addtion, there are several problems such as corrosion of deck plates in terms of constructability and maintenance. Therefore, in this study, it is attempted to develop a removal-deck plate formwork system for beams by removing deck plates after concrete curing. The system consists of a deck plate module that acts as form, a frame preventing deformation by concrete lateral pressure, stirrup frame, and connector that combines these. As a result of this research, it is verified that it has higher constructability, efficiently prevents deformation caused by concrete lateral pressure and could be easily removed in the developed formwork system.