• 환경영향평가
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• 제9권1호
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• pp.75-86
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• 2000

The purpose of this work was to document the conditions regarding organic solvent exposure to the workers in paint industry. Air concentrations of organic solvents were measured by passive personal samplers and analyzed by a gas chromatography. Urine samples for hippuric test were also taken from 330 workers who have worked at seven domestic factories for more than two years. Amongst 25 organic elements detected in the indoor environment of working places, toluene was the most common element, and methanol showed the highest mean concentration(18.2ppm). A few elements including methylethyl ketone and toluene partially exceeded the Korean Permissible Exposure Limit. A lack of environmental facilities such as exhaust ventilation, automatic cleaning system, and personal safety devices at present work plaus brings about various occupational diseases.

• Journal of electromagnetic engineering and science
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• 제19권1호
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• pp.56-63
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• 2019

Typical negative group delay circuits (NGDC) are analyzed in terms of signal attenuation, group delay, and bandwidth using S-parameters. By inverting these formulations, we derive and present the design equations (for NGD circuit elements) for a desired specification of the two among the three parameters. The proposed design method is validated through simulation examples for narrow- and wide-band pulse inputs in the time and frequency domains. Moreover, an NGDC composed of lumped elements is fabricated at 1 GHz for measurement. As a function of frequency, the circuit-/EM-simulated and measured group delays are in good agreement. The provided simple NGDC design equations may be useful for many applications that require compensations of some signal delays.

• 한국실내디자인학회논문집
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• 제21권3호
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• pp.103-110
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• 2012

Interior Coordination is the activity of making characteristic living space by planning and harmonizing various interior elements. In modern society, the taste and needs of the residents are getting varied and segmented, and the role of interior coordination is getting more important because that reflects cultural codes and trends and satisfies residents' needs. This study aims to investigate awareness and needs about interior coordination targeting apartment residents, and to provide fundamental data that could attribute to the planning of unique and diverse residential spaces. Methods of study include the literature research and the empirical study. Elements of interior coordination were extracted through the literature review, and the questionnaire was developed using these elements. And then a survey was carried out targeting apartment residents of Busan. The result shows that most of the residents were much interested in interior coordination, and they recognized it's importance. They wanted to plan and select the elements by themselves, but were passive in actual execution because of the difficulties in execution methods and economical conditions. There were certain differences between the styles of their own houses and the preferred styles, but they did not try actively to reconcile the differences. Therefore, various methods of interior coordination should be developed and proposed which are easy and effective for actual execution, and various media should be provided by which residents could easily get informations on design elements. Also, the concept and method of interior coordination should be considered from the very first stage of residential planning, and the replacement and modification of interior coordination could be easily done according to the change of life cycle and life styles.

• KIEAE Journal
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• 제13권1호
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• pp.47-55
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• 2013

This study aims to evaluate the correlation between vertical solar radiation and the level of heating load according to the location and type of housing in multi-family apartments. This study shows that heating load is related with factors such as wall loss, window loss, ventilation loss and solar radiation gain. The heating load increases in the order of the middle floors, the highest floors and the lowest floors. The lowest and the highest floors are the most vulnerable floors, and it should be as emphasized as the middle floors. The heating load saving proposal contains 52 Alt. that shows heating load savings from min. 4% to max. 49%. The goal is to reduce the heating load of the highest and the lowest floors to the level of the middle floors. The result showed that there are 3 Alt. for the lowest floors and 16 Alt. for the highest floors as the heating load saving proposal. This study suggests integrated application to compose saving elements of heating load. so it could be utilized as a data for the construction of passive houses.

• Structural Engineering and Mechanics
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• 제33권1호
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• pp.79-93
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• 2009

This paper investigates the possibility of controlling the response of typical portal frame structures to blast loading using a combination of semi-active and passive control devices. A one storey reinforced concrete portal frame is modelled using non-linear finite elements with each column discretised into multiple elements to capture the higher frequency modes of column vibration response that are typical features of blast responses. The model structure is subjected to blast loads of varying duration, magnitude and shape, and the critical aspects of the response are investigated over a range of structural periods in the form of blast load response spectra. It is found that the shape or length of the blast load is not a factor in the response, as long as the period is less than 25% of the fundamental structural period. Thus, blast load response can be expressed strictly as a function of the momentum applied to the structure by a blast load. The optimal device arrangements are found to be those that reduce the first peak of the structural displacement and also reduce the subsequent free vibration of the structure. Semi-active devices that do not increase base shear demands on the foundations in combination with a passive yielding tendon are found to provide the most effective control, particularly if base shear demand is an important consideration, as with older structures. The overall results are summarised as response spectra for eventual potential use within standard structural design paradigms.

• 한국항행학회논문지
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• 제23권2호
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• pp.172-178
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• 2019

본 논문에서는 LTCC 다층기판으로 구현할 수동 소자를 수축공정과 무수축공정으로 구분하여 설계, 제작하고 분석하였다. 유전율 7 또는40의 두 종류 세라믹 소재를 사용하여 기본 형태의 수동소자를 다양하게 두 가지 공정으로 제작하여 특성을 비교하였다. 유전율40 기판을 사용할 때 수축공정은 X, Y 방향에서 17%, Z 방향에서 36%의 수축율을 보이는 것과 비교하여, 무수축공정은 X,Y 방향에서 변화하지 않고 Z 방향으로만 43% 수축하여 평면상에서 높은 치수 정밀도와 표면 평탄도를 얻을 수 있다. 측정 값으로 부터 매개 변수를 이용한 경험적 해석 식을 이용하여 제작한 LTCC 소자의 인덕턴스 및 커패시턴스를 추정하였으며 설계 라이브러리 형태로 구현하였다. 유전율과 제작 공정에 따라 인덕터의 권선수와 단위 면적에 따른 커패시턴스를 측정하여 권선수 및 단위면적에 따른 소자값을 예측할 수 있는 다항식을 제시하였다.

• 한국건설관리학회논문집
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• 제24권1호
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• pp.61-70
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• 2023

경제적인 측면이나 친환경적인 측면의 사유로 인해, 노후 건축물을 대상으로 그린리모델링 사업이 활발하게 진행되고 있다. 한편, 그린리모델링 사업을 추진하는 과정에서, 기존에는 설계자 및 엔지니어의 주관적 경험 및 지식에 기반하여 그린리모델링 계획이 개발되어 왔고, 이로 인해 경제성 등의 측면에서 효율적인 의사결정이 부족했다. 이에 본 연구에서는 노후 건축물의 속성을 분석하고 이에 따른 적정 리모델링 계획을 제안할 수 있는 온톨로지 기반 그린리모델링 의사결정 지원 모델을 구축하였다. 개발된 모델에서는 건축물의 기본 속성을 입력하면 온톨로지를 통한 웹검색을 기반으로 패시브 액티브 요소로 구성된 적정 리모델링 계획을 제공할 수 있다. 연구를 통해 개발된 결과물을 활용하면, 리모델링 사례의 증가에 따른 웹기반의 메타 데이터 검색을 통해 보다 객관적인 적정 리모델링 대안에 대한 의사결정 지원이 가능할 것으로 기대된다.

• 한국광물학회:학술대회논문집
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• 한국광물학회.한국암석학회 2003년도 공동학술발표회 논문집
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• pp.54-54
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• 2003

The metasedimentary rocks together with various granitoids are the main constituents in Taebaeksan gneiss complex, northern Yeongnam Massif. Chemical compositions of sedimentary rocks may reflect the nature of the provenance and could be crucial for understanding the evolution of early continental crust. Previous workers have suggested that the provenance and tectonic studies based on the geochemistry of sediments are applicable to the Precambrian samples. In this study we analyzed the major, trace and REE elements of metasedimentary rocks to understand their provenance and tectonic setting during sedimentation. The overall geochemical characteristics of metasedimentary rocks are similar to those of average shale of the post-Archean. Major element chemistry indicates mature and sorted nature of the sediments. The degree of weathering in the source rocks the is not uniform, as inferred from a large scatter in chemical indices of weathering (CIW). The immobile trace elements such as Th, Sc, and REE can be used to discriminate various sedimentary processes. The Th/sc ratios (0.9 - 4.4) are larger than those of the upper crust and average shale, suggesting that the felsic source predominates. The contents of Ni and Cr and the variations in the ratio of compatible to incompatible elements are similar to the average post-Archean shale. Uniform chondrite-normalized REE pattern with the LREE enrichment (LaN/SmN = 4.9 ${\pm}$ 0.4) and slight negative Eu anomalies (Eu/Eu$\^$*/ = 0.7 ${\pm}$ 0.1) also support this observation. The presence of negative Eu anomaly indicates that intracrustal igneous processes involving plagioclase separation have affected the provenance rocks. The LREE enrichment implies the major role of felsic rocks in source rocks. The eNd (1.9 Ga) values of metasediment rocks vary from 9.4 to 6.7, corresponding to TDM of 2.9 - 2.7 Ga. On the other hand, the 147Sm/144Nd ratios are 0.1079 - 0.1101, corresponding to typical tettigenous sediments. The geochemical features of metasedimentary rocks such as high abundances of large ion lithophile elements, high ratios of Th/Sc and La/Sm, commonly high Th/U ratios, negative Eu anomalies, and negative eNd, suggest a provenance consisting virtually entirely of recycled upper continental crust in passive margin environment. Tectonic discrimination diagrams based upon major element compositions also support this suggestion. In conjunction with igneous activity and metamorphism in the convergent margin setting at 1.8 - 1. 9 Ga, the transition from passive margin to active margin characterize the Paleoproterozoic crustal evolution in northern Yeongnam Massif.

• 대한전자공학회논문지TC
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• 제45권8호
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• pp.114-120
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• 2008

본 논문에서는 단락 개방 Calibration (SOC) 방법을 이용하여 MIM 구조로 구성된 커패시터의 기생 소자 값들을 추출하였다. Strip line 으로 구성된 short, open, MIM 구조들의 산란 파라미터 행렬들은 전자기 시뮬레이터 및 벡터 네트웍 분석기를 이용하여 측정되었다. 전자기 시뮬레이션들은 3차원 구조 해석에 적합해왔던 유한 유소법 (FEM)을 이용하여 수행되었다. 적층 구조 내부에 형성된 MIM 커패시터의 전자기 영향들은 집중 소자들로 구성된 II 형 등가 회로로 제안되었고, 2 포트 네트웍 해석을 수행함으로써, 측정된 산란 파라미터들과 등가회로 소자들 간의 관계를 보였다. 제안된 SOC 방법을 이용하여 추출된 집중 소자들은 주파수 독립적인 결과를 나타낸다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.1039-1042
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• 2005

Recently, a considerable number of studies have been made on the $RFID^{[1-6]}$ systems. RFID is a technique of identifying an object using radio frequency transmission. The technology can be used to identify, track, sort or detect a wide variety of objects. The RFID system is composed of two main elements: a reader and a tag. Tags can either be active (powered by battery) or passive (powered by the reader field). The passive tags communicate back to the reader with a technique called 'backscatter'. RFID technology can be applied to the supply chain, security, logistics industry and etc. Especially, UHF RFID is worth noticing because of its relatively long identification range and commercial UHF RFID systems are under development. In this paper, we designed and implemented a UHF RFID reader firmware for ISO/IEC 18000-6 Type B specification.