• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.5
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• pp.124-135
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• 2011

The capacity of bearings installed at abutments and piers for continuous bridges is usually determined by the magnitude of the maximum vertical reaction at each support and the capacity of bearings placed at piers is higher than that at abutments. In this study, the possibility of the improved seismic performance of base-isolated continuous skew bridges was investigated by analysing the variation of the seismic behavior of them according to three arrangements of bearings. Based on the conventional arrangement of bearings(Case A), three arrangements of bearings such as Case A, Case B and Case C were selected considering the variation of the horizontal stiffness of the lead rubber bearing(LRB) installed at the pier. The seismic behavior of the total 36 skew bridges was investigated by conducting the response spectrum analysis using the hybrid response spectrum considered the effect of LRB's damping. Results of analyses show that a more desirable seismic behavior of base-isolated continuous skew bridges can be obtained by reducing the magnitude of the horizontal stiffness of LRB placed at the pier to similar to or less than that of LRB installed at abutments. The variation of LRB's stiffness at the pier brings about period elongation and the change of mode shapes of base-isolated skew bridges and results in the reduction of the total base shear, the maximum base shear at the pier and the girder stresses. Although positive effects on the seismic behavior of base-isolated skew bridges caused by the change of arrangement of bearings decreased slighty with an increase in the flexibility of the substructure, the proposed arrangements of bearings bring about the improved seismic performance of base-isolated continuous skew plate girder bridges with less than 10m height of piers.

• The Science & Technology
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• v.31 no.4 s.347
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• pp.88-89
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• 1998

새 정부가 출범하면서 과학기술부는 무서운 진통 끝에 태어났다. 그런데 인수위원회에서 확정시킨 100대 과제를 보면 과학기술부에 무거운 책임이 실어져 있지 않은 것 같다 IMF위기 돌파는 기술혁신의 성공여부에 달려있다. 기술혁신은 연구개발의 뒷받침없이는 소기의 성과를 거둘 수 없는 것이다. 세계에서 제일 싸고, 제일 좋고, 부가가치가 높은 혁신상품을 만들어 내려면 기초과학 뿐만 아니라 기초기술에 대한 연구없이는 불가능한 것이다. 응용연구 ,개발연구도 기초과학 연구와 기초기술 연구가 밑받침 되어야만 세계시장에서 경쟁할 수 있는 제품 개발이 가능한 것이다.

• 정보화사회
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• s.117
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• pp.36-39
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• 1997

노트PC, 휴대전화, PHS등 정보통신 툴의 거의 대부분에 "액정 Flat-Display"가 사용되고 있다. 19세기에 발견되었고 금세기들어 이용법이 확립된 "액정"은 Flat-Display로서 오늘날 정보통신을 밑받침하는 하나의 요소가 되고 있다. 여기서는 "액정 디스프레이"를 비롯 일상 아무거리낌없이 쓰고 있는 정보통신 단말기등의 디스프레이를 통하여, 그 기술 개발과 풍요로운 정보사회와의 연결고리 나아가서 그 미래를 탐색해 본다.

• Journal of the Korean Society of Floral Art and Design
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• no.45
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• pp.13-29
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• 2021

Under the recognition that the technological system of traditional flower design in Korea has been passed down from the past to the present, we extracted the type of design form from the flower decoration of the Joseon Dynasty, analyzed the expression technique, and examined the relationship with the modern traditional flower decoration in this study. As a result, most of the flower design works of the Joseon Dynasty mainly expressed one focal point at the central starting point. One central branch line was mainly used, and cut leaves were mainly used as the base material. Similar to the Joseon Dynasty, one central starting point and a base made of leaves are mainly used In modern flower design. In the frequency of use by expression technique, the stem exposure technique was used the most, and cut flowers and cut stems were used at a similar frequency in all techniques. As plant materials, cut flowers and cut stems were mainly used. In addition, non-plant materials such as feathers, fans, and brushes were also used for decoration. In conclusion, it can be seen that traditional flower decorations in Korea were systematically established in the Joseon Dynasty in terms of expression techniques and high-level flower design works were made. In the future, it will be necessary to study the history of our flower designs in more diverse ways and to develop modern flower designs while preserving historical traditions.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.349-350
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• 2008

지능 로봇은 표현 가능한 사물, 공간을 모델링하기 위해 주변 환경을 인지하고, 자신이 수행할 수 있는 행동을 결합하여 임무를 수행하게 된다. 이를 위해 온톨로지를 사용하여 사물, 공간, 상황 및 행동을 표현하고 특정 임무 수행을 위한 자바 기반 Rule을 통해 다양한 추론 방법을 제공하는 로봇 지식 체계를 사용하였다. 사용된 로봇 지식 체계는 생성되는 인스턴스가 자료의 클래스와 속성 값이 일관성 있고 다른 자료와 모순되지 않음을 보장해 준다. 이러한 로봇 지식 체계를 효율적으로 사용하기 위해서는 완전한 온톨로지 인스턴스의 생성이 밑받침 되어야 한다. 하지만 실제 환경에서 로봇이 Vision Sensor를 통해 사물을 인식할 때 False Positive False Negative와 같은 인식 오류를 발생시키는 문제점이 있다. 이를 보완 하기 위해 본 논문에서는 물체와 물체간의 Spatial Relation, Temporal Relation과 각 물체마다의 인식률 및 속성을 고려하여 물체 인식 오류에서도 안정적으로 인스턴스 관리를 가능하게 하는 Rule 기반의 일식오류 검출 필터를 제안한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.395-399
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• 2017

The LPI fuel filter housings used in automobiles were made from conventional die castings but have recently been developed by cold forging to improve the weight and durability. On the other hand, a sink may develop at the core of the forged product due to the resulting T-shape, which not only reduces the aesthetics, but also increases the post-processing cost of the product. Therefore, this research focused on methods to predict and mitigate sink development and progression during the T-shape forging process. Finite element analysis of the forging process was first performed to determine the optimal initial workpiece devoid of burrs and underfills. An accurate sink prediction was then obtained via metal flow analysis, which was a result of the finite element simulation. Through finite element analysis, it was confirmed that sink development is a product of the differences in nodal velocities arising from the T-shaped forging process. Consequently, a pad was inserted beneath the sink to minimize these velocity differences. The results yielded significant improvement with regard to the sink defect. This method was practically applied to an industrial site to validate the sink improvement.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.383-399
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• 2020

Optimizing the spacing of the disc cutter is a key element in the design of the TBM cutter head, which determines the drilling performance of the TBM. The full-scale linear cutting test is known as the most reliable and accurate test for calculating the spacing of the disc cutter, but it has the disadvantage of costly and time-consuming for the full-scale experiment. In this study, through the numerical analysis study based on the discrete element method, the tendency between Specific Energy-S/P ratio according to uniaxial compression strength and penetration depth of rock was analyzed, and the optimum spacing of 17-inch disc cutter was derived. To examine the appropriateness of the numerical analysis model, the rolling force acting on the disc cutter was compared and reviewed with the CSM model. As a result of numerical analysis for the linear cutting test, the rolling force acting on the disc cutter was analyzed to be similar to the rolling force derived from the theoretical formula of the CSM model. From the numerical analysis on 5 UCS cases (50 MPa, 70 MPa, 100 MPa, 150 MPa, 200 MPa), it is found that the range of the optimum spacing of the disc cutter decreases as the rock strength increases. And it can be concluded that 80~100 mm of disc cutter spacing is the optimum range having minimum specific energy regardless of rock strength. This tends to coincide with the optimal spacing of previously reported disk cutters, which underpins the disk cutter spacing calculated through this study.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.1-12
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• 2021

In the design of a tunnel boring machine (TBM), the excavation efficiency of the equipment depends on the design of the cutter head, which is directly in contact with the ground. Especially, the allocation of disc cutter is crucial issue. Disc cutters can be divided into center cutter zone, inner cutter zone and transition cutter zone depending on where they are placed. Many studies have been conducted to identify optimal cutting conditions for face cutters. However, research to determine the optimal cutting conditions for the transition cutter has been relatively incomplete. In this study, to identify the optimal cutting conditions for the transition cutter, numerical analysis using discrete element method was performed, and the specific energy curve according to the angle between the transition cutters was drawn to find out the optimum cutting conditions. The results show that the angle between the transition cutters showing minimum specific energy in the transition cutter zone is 9°. Transition cutter zone was divided into three sections according to the slope angle of the transition cutter. It is also found that, the greater the slope angle of the transition cutter. This finding shows good agreement with the present design of transition cutter zone.

• Journal of Industrial Convergence
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• v.21 no.5
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• pp.1-13
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• 2023

Carbon neutrality is the concept of reducing greenhouse gases emitted by human activities and making actual emissions zero through removal of remaining gases. It is also called "Net-Zero" and "carbon zero". Korea has declared a "2050 Carbon Neutrality policy" to cope with the climate change crisis. Various carbon reduction legislative processes are underway. Since carbon neutrality requires changes in industrial technology, it is important to prepare a system for carbon zero. This paper aims to understand the status and trends of global carbon neutrality technology. Therefore, ROK's web platform "www.naver.com." was selected as the data collection scope. Korean online articles related to carbon neutrality were collected. Carbon neutrality technology trends were analyzed by future signal methodology and Word2Vec algorithm which is a neural network deep learning technology. As a result, technology advancement in the steel and petrochemical sectors, which are carbon over-release industries, was required. Investment feasibility in the electric vehicle sector and technology advancement were on the rise. It seems that the government's support for carbon neutrality and the creation of global technology infrastructure should be supported. In addition, it is urgent to cultivate human resources, and possible to confirm the need to prepare support policies for carbon neutrality.

• Journal of Sericultural and Entomological Science
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• v.13 no.1
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• pp.23-29
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• 1971

As a result of analyzing the change of material substance of all sorts biochemically and comparing the control with ${\gamma}$-ray irradiation (800${\gamma}$, 40 Min), incubating the silkworm eggs (Bombyx mori L.) as the objective in the process of growth of embyro shortly before hatching, the following conclusion has been found. 1. Ascorbic acid has shown the maximum increase of 319 r/g in the Byong B embyro stage and in other words it has increased during the period of vigorous metabolism of the materials in eggs but it has decreased before hatching after that period. 2. Triglyceride has shown the increase of 27.54 mg/g in the Byong A stage, the early period of incubation and in other words it has increased in the period of activation of cells in eggs but it has gradually decreased during the growth of embyro after that period. Great change of either total cholesterol or free cholesterol has not been shown from the early period till shortly before hatching. 3. Free fatty acid has shown the minimum decrease of 257.4$\mu$ mole/g in the Byong A stage in which triglyceride increases greatly. On the contrary, it has shown the increase of 1, 020.0$\mu$ mole/g in Ki A stage in which triglyceride decreases. As a whole, the fact that free fatty acid increases according to the growth of embyro in eggs has been found. 4. Glucose has shown the increase of 281.2 mg/g in control during tile Pigment stage and it has shown the increase of 179.6 mg/g in ${\gamma}$-ray irradiation during the same period. The difference in quantity between the former and the latter is due to the fact that the growth of embyro has been influenced by the radio active. Glucose has changed with free fatty acid and phosphorus the other way round. 5. Control organic phosphorus has shewh the increase of 5.23mg/g during the Byong B or Ki A in which organ and tissue in the emhyro has been formed. Organic phosphorus in ${\gamma}$-ray irradiation has shown the increase of 5.73mg/g during Ki B. Inorganic phosphorus has shown only a little change in the control and ${\gamma}$-ray irradiation. The phosphorus in both has shown a little quantity in the ${\gamma}$-ray irradiation in the early period of incubation. After the Ki A embyro, it has increased rapidly and it has increased till the hatching more continually than in control. The about results of the research will be helpful and instructive to the betterment and improvement, breeding and management of animals and plants.