• 소성∙가공
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• 제32권3호
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• pp.153-159
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• 2023

This paper presents the optimal design of a heating system using radiant heating elements for application in smart farms. Smart farming, an advanced agricultural technology, is based on artificial intelligence and the internet of things and promotes crop production. Temperature and humidity regulation is critical in smart farms, and thus, a heating system is essential. Radiant heating elements are devices that generate heat using electrical energy. Among other applications, radiant heating elements are used for environmental control and heating in smart farm greenhouses. The performance of these elements is directly related to their electrical energy consumption. Therefore, achieving a balance between efficient electrical energy consumption and maximum heating performance in smart farms is crucial for the optimal design of radiant heating elements. In this study, the size, electrical energy supply, heat generation efficiency, and heating performance of radiant heating elements used in these heating systems were investigated. The effects of the size and electrical energy supply of radiant heating elements on the heating performance were experimentally analyzed. As the radiant heating element size increased, the heat generation efficiency improved, but the electrical energy consumption also increased. In addition, increasing the electrical energy supply improved both the heat generation efficiency and heating performance of the radiant heating elements. Based on these results, a method for determining the optimal size and electrical energy supply of radiant heating elements was proposed, and it reduced the electrical energy consumption while maintaining an appropriate heating performance in smart farms. These research findings are expected to contribute to energy conservation and performance improvement in smart farming.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.808-818
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• 2022

In this research paper, we investigated the cryogenic line chill down characteristics of liquefied natural gas (LNG). A numerical analysis model was established and verified so that it can calculate the precise cooling characteristics of cryogenic fluid for the stable and safe utilization especially such as LNG and liquid hydrogen. The numerical modeling was programmed by C++ as an one-dimensional homogeneous model. The thermohydraulic cooling process was simulated using mass, momentum, energy conservation equations and appropriate heat transfer correlations. In this process, the relevant heat transfer correlations for nuclear boiling, transition boiling, film boiling, and single-phase heat transfer that can predict the experimental results were implemented. To verify the numerical modeling, several cryogenic line chill down experiments using LNG were conducted at the Korea Institute of Machinery & Materials (KIMM) LNG and Cryogenic Technology Center.

• Acta Via Serica
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• 제8권1호
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• pp.1-30
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• 2023

Traditional Kurdish weavings are among the world's most ancient living textile traditions. One of the largest regional ethnic and linguistic groups, Kurds have inhabited a significant part of Western Asia for millennia. Historically, Kurdish territories were crisscrossed by old and important trade routes, including the Silk Roads. This led to the formation of some of the most significant Kurdish artistic and cultural traditions, including textiles, which influenced and were influenced by those of other non-Kurdish ethnic groups from Caucasia to Central Asia and beyond. One example of Kurdish carpet traditions born in the eighteenth century at the cross-sections of Safavid (1501-1736) urban carpets workshops and centuries-old indigenous Kurdish tribal/rural weaves is senneh gelim or sojaee. A finely flatwoven carpet that was exchanged regionally and internationally as a diplomatic gift and a highly prized commodity. Although in decline, senneh gelims continue to be made by Kurdish women weavers in their original birthplace Sanandaj, the provincial capital of Iranian Kurdistan to date. This study adopts an inter-disciplinary approach to present an image of senneh gelim and women gelim weavers, tracing the developmental trajectories of the craft from the eighteenth century to the present time by drawing on extant art-historical and social scientific studies along with primary ethnographic data collected in Iranian Kurdistan (2018-2019). It investigates the craft tradition's historical origin, various aspects such as techniques, materials, aesthetics, functions, and meanings, and how these transformed over time. Additionally, the paper looks at the social contexts of production, focusing on women carpet weavers and how their socioeconomic and cultural situation has formed senneh carpet production in the past and present and the implications for long-term preservation.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.460-474
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• 2023

A simple but accurate mathematical model is crucial for dynamic simulations and controller design of helical coil once-through steam generator (OTSG). This paper presents a three-region movable boundary dynamic model of the helical coil OTSG. Based on the secondary side fluid conditions, the OTSG is divided into subcooled region (two control volumes), two-phase region (two control volumes) and superheated region (three control volumes) with movable boiling boundaries between each region. The nonlinear dynamic model is derived based on mass, energy and momentum conservation equations. And the linear model is obtained by using the transfer function and state space transformation, which is a 37-order model of five input and three output. Validations are made under full-power steady-state condition and four transient conditions. Results show good agreements among the nonlinear model, linear model and the RELAP5 model, with acceptable errors. This model can be applied to dynamic simulations and controller design of helical coil OTSG with constant primary-side flow rate.

• 한국지형학회지
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• 제18권1호
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• pp.73-83
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• 2011

본 연구는 지오파크(Geopark)에 대한 개념과 탄생 과정 그리고 지리학 분야에서의 지오파크 활동 등을 고찰하고, 현재 논란이 되고 있는 지오파크 명칭 문제를 논의한다. 지오파크는 세계지리학연합(IGU)과 세계지질학연합(IUGS)의 상호 협력관계로 출발한 것이다. 그런데 우리나라에서는 '지질공원법'이란 체계를 이용하여 특정 분야에서만 지오파크를 논의하려는 부분은 매우 잘못된 것이다. 지오파크에서의 활동은 지역의 지형·지질을 비롯한 자연물의 보전이라는 측면을 가지고 있다. 지오파크는 어느 특정 학문 분야의 전유물이 아니다. 따라서 지오파크 태동기에 있는 우리나라에서는 지오파크 명칭에 대한 논의와 합의가 선결 과제라고 생각한다.

• Structural Engineering and Mechanics
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• 제88권3호
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• pp.221-238
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• 2023

This paper developed and examined a novel passive vibration isolator (i.e., "X-inerter") motivated by combining a bio-inspired structure and a rack-pinion inerter. The bio-inspired structure provided nonlinear stiffness and damping owing to its geometric nonlinearity. In addition, the behavior was further enhanced by a gear inerter that produced a special nonlinear inertia effect; thus, an X-inerter was developed. As a result, the X-inerter can achieve both high-static-low-dynamic stiffness (HSLDS) and quasi-zero stiffness (QZS), obtaining ultra-low frequency isolation. Furthermore, the installed inerter can produce a coupled nonlinear inertia and damping effect, leading to an anti-resonance frequency near the resonance, wide isolation region, and low resonance peak. Both static and dynamic analyses of the proposed isolator were conducted and the structural parameters' influence was comprehensively investigated. The X-inerter was proven to be comparatively more stable in the ultra-low frequency than the benchmarking QZS isolator due to the nonlinear damping and inertia properties. Moreover, the inertia effect could suppress the bio-inspired structure's super- and sub-harmonic resonance. Therefore, the X-inerter isolator generally possesses desirable nonlinear stiffness, nonlinear damping, and unique nonlinear inertia, designed to achieve the ultra-low natural frequency, the anti-resonance property, and a wide isolation region with a low resonance peak.

• 문화기술의 융합
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• 제10권4호
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• pp.495-499
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• 2024

이 연구는 지속 가능한 포장 디자인의 중요성, 정의, 핵심 전략 및 향후 방향을 요약합니다. 현대 사회에서 지속 가능한 포장 디자인은 환경 보호와 자원 절약에 중점을 둘 뿐만 아니라 경제, 사회 및 문화의 지속 가능한 발전을 포함합니다. 이 연구에서는 환경 친화적인 재료의 사용, 포장 디자인의 최적화, 포장의 재활용성 및 재사용성을 향상 시켜 환경 부담을 줄이고 생태 균형을 촉진하기 위한 전략에 대해 자세히 설명합니다. 또한 이 연구는 단순화된 디자인 개념과 모듈식 시스템의 채택, 패키징의 다기능성 증가와 같은 디자인 혁신의 중요성을 강조합니다.또한 설계에서 폐기까지의 모든 단계가 환경에 미치는 영향을 최소화하기 위해 포장 설계에 수명 주기 평가를 적용하는 것에 대해 논의합니다. 마지막으로 지속 가능한 포장 디자인의 환경 및 사회적 이점에도 불구하고 실제로는 여전히 기술, 경제 및 규제의 도전에 직면해 있습니다.미래 디자인은 지속 가능한 포장의 광범위한 채택과 관행을 촉진하기 위해 학제 간 협력, 첨단 기술의 통합, 소비자 교육 및 참여, 강화된 정책 및 표준 제정이 필요합니다.

• 한국환경복원기술학회지
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• 제23권3호
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• pp.23-43
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• 2020

The purpose of this paper is to create ecological values for urban rivers. For this, the paper looks into river bed structures and how nearby lands are used. This study was performed to set the specific sections for analysis through a field investigation of the infrastructure conditions, surrounding land use, and the inter habitat structure of Seongnaecheon(Stream). A total of 780 individuals from 31 species of wild birds appeared in Seongnaecheon(Stream). According to foraging guild's habitat, there were 9 species of water, 8 types of water edges, 5 types of crowns, 5 types of shrubs, 2 types of tree trunks, 2 types of birds of raptors, and 355 individuals of water, 243 shrubs, 90 crowns, 84 water edges and 5 raptors. Many water birds were observed at the site where the Seongnaecheon(Stream) sandy plains and wetland herbaceous area were developed and the open water was secured. Most of the forest birds appeared on levee slope connected with forest around and riverside with fewer facilities for use. The species diversity index of Shannon, the entire section of Seongnaecheon(Stream), was 2.2697 and the downstream ecological landscape conservation area of Seongnaecheon(Stream) was found to be useful as a habitat for wild birds in the city compared to other sections. Some sections of Seongnaecheon (Stream) had low species diversity index due to lack of green space and surrounding urbanization areas. In choosing target species, I researched the special features of the habitats and the habitation structure of wild birds in each zone. Regarding detailed plans, by classifying the breeding place & roosting site and the roosting site & shelter that took account of the inhabitation characteristics of the target species in different sections, this paper suggested the major plant species and multilayer planting structures. Moreover, this study proposed the development of habitats for water birds and forest birds along with the connection of the green network for improving the Eco-corridor linkage and inhabitation features in Seongnaecheon(Stream).

• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.661-670
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• 2017

지리산 아고산대 주요 침엽수(주목, 잣나무, 구상나무)와 신갈나무를 이용하여 50년간의 산소동위원소연대기(1966~2015)를 작성하였다. 산소동위원소연대기 작성은 크로스데이팅(cross-dating) 결과가 우수한 4본을 각 수종에서 선발하여 실시하였다. 동일 수종 내 임목 간 산소동위원소연대기의 상관분석 결과 모두 유의성(p < 0.001) 높은 상관이 있는 것으로 확인되었으며, EPS도 0.85 이상이었다. 동일 수종 내 임목 간 상관분석뿐만 아니라 수종간 상관분석에서도 유의성(p < 0.001) 높은 상관관계가 확인되었다. 기후요소(강수량, 기온)와 산소동위원소와의 관계를 조사하기 위한 반응함수 분석에서 주목은 당년 5월 강수량과 유의성 있는 부의 상관을 보였으며, 구상나무는 4월 강수량과 유의성 있는 부의 상관을 보였다. 향후 주목과 구상나무에 대한 장기간의 산소동위원소연대기가 작성된다면 과거 측정하지 못한 장기간의 4월과 5월 강수량 복원이 가능할 것이다.

• 한국경제지리학회지
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• 제19권2호
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• pp.242-264
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• 2016

풍부한 자연환경과 다양한 문화 역사 유산을 갖춘 동남아에서 관광은 국가 및 지역경제 발전의 주요 부문이다. 하지만 굴뚝 없는 산업으로 인식되어 온 관광 산업이 점차 대형화 지구적 표준화되어 감에 따라, 관광산업의 이윤과 사회 환경적 비용의 불균등한 배분에 따른 문제제기가 이어지고 있다. 이에 보존과 지역발전을 동시에 추구하는 지역사회기반생태관광(CBET)이 주목할 만한 대안으로 부상하고 있다. 본 논문은 인도네시아와 캄보디아에서의 CBET의 발전경로와 현황을 상호 비교함으로써, 동남아시아에서 생태관광을 통한 지역사회발전의 현황과 과제를 검토하는 것을 목적으로 한다. 구체적으로 인도네시아 발리의 마을관광네트워크인 JED의 회원마을과 캄보디아 스텅트렝 주의 람사르 습지보전지역의 CBET 프로그램의 형성과정을 분석하고 두 사례의 비교를 통해 생태관광을 통한 지역사회발전 전략의 가능성과 한계를 짚어보았다. 두 사례 모두에서 관광의 핵심자원인 생태환경의 보호와 환경인식 개선과 더불어 지역공동체에서 관광으로 인한 직간접적인 사회경제적 이윤이 창출되는 긍정적 결과를 확인하였다. 하지만 두 마을 공동체에 조직된 CBET 거버넌스의 안정성과 관리역량에는 차별적이지만 상당한 한계가 존재하며, 이는 해당 지역사회관광 프로그램의 효율성과 지속가능성에 제약조건이 되고 있다. 결론부분에서는 사례연구를 바탕으로 사회적 경제를 매개로 한 CBET 프로그램 지원을 통해 한국의 대 동남아시아 관광 ODA의 가능성을 제시하였다.