• 센서학회지
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• 제29권2호
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• pp.128-132
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• 2020

Total organic carbon (TOC) analysis equipment, which was previously used to prevent eutrophication in advance, is heavy, bulky, and expensive; therefore, so it is difficult to be carried and has been used as an experimental unit. In this study, a through-carbon analysis chip that integrates pretreatment through photocatalytic oxidation and carbon dioxide measurement using a pH indicator was investigated. Both the total carbon - inorganic carbon method and the nonpurgeable organic carbon (NPOC) measurement method require an acidification part for injecting an acid solution for inorganic carbon measurement and removal, an oxidation part for total carbon or NPOC oxidation and a measurement part for Carbon dioxide (CO₂) measurement. Among them, the measurement of oxidation and CO₂ requires physical technology. The proposed TOC analysis chip decomposed into CO₂ as a result of the oxidizing of organic carbon using a photocatalyst, and the pH indicator that was changed by the generated CO₂ was optically measured. Although the area of the sample of the oxidation part and the pH indicator of the measurement part were distinguished in an enclosed space, CO₂ was quantified by producing an oxidation part and a measurement part that shared the same air in one chip. The proposed TOC analysis chip is less expensive and smaller, cost and size are disadvantages of existing organic carbon analysis equipment, because it does not require a separate carrier gas to transport the CO₂ gas in the oxidation part to the measurement part.

• 한국축산시설환경학회지
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• 제11권2호
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• pp.97-102
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• 2005

Anaerobic decomposition is one of the most common processes in nature and has been extensively used in waste and wastewater treatment for several centuries. New applications and system modifications continue to be adapted making the process either more effective, less expensive, or suited to the particular waste in question and the operation to which it is to be applied. Animal manure is a highly biodegradable organic material and will naturally undergo anaerobic fermentation, resulting in release of noxious odors, such as in manure storage pits. Depending on the presence or absence of oxygen in the manure, biological treatment process may be either aerobic or anaerobic. Under anaerobic conditions, bacteria carry on fermentative metabolisms to break down the complex organic substances into simpler organic acids and then convert them to ultimately formed methane and carbon dioxide. Anaerobic biological systems for animal manure treatment include anaerobic lagoons and anaerobic digesters. Methane and carbon dioxide are the principal end products of controlled anaerobic digestion. These two gases are collectively called biogas. The biogas contains $60\~70\%$ methane and can be used directly as a fuel for heating or electrical power generation. Trace amounts of ammonia and hydrogen sulfide ($100\~300\;ppm$) are always present in the biogas stream. Anaerobic lagoons have found widespread application in the treatment of animal manure because of their low initial costs, ease of operation and convenience of loading by gravity flow from the animal buildings. The main disadvantage is the release of odors from the open surfaces of the lagoons, especially during the spring warm-up or if the lagoons are overloaded. However, if the lagoons are covered and gases are collected, the odor problems can be solved and the methane collected can be used as a fuel. Anaerobic digesters are air-tight, enclosed vessels and are used to digest manure in a well-controlled environment, thus resulting in higher digestion rates and smaller space requirements than anaerobic lagoons. Anaerobic digesters are usually heated and mixed to maximize treatment efficiency and biogas production. The objective of this work was to review a current anaerobic biological treatment of animal manure for effective new technologies in the future.

• 농촌계획
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• 제2권1호
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• pp.69-78
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• 1996

Environmental impact assessment survey reflecting farmers` opinion on the residence and production space in rural settlement area by ORD showed that more than 86% of respondents thought their reservoirs and waterways (small rivers) were getting seriously contaminated primarily by garbage and livestock manure. A typical rural settlement unit was taken to assess the impact of improper management of livestock manure in the farms on the water quality of small river flowing down along the villages where swine and dairy farms were situated in Daejook 2, 3-ri, Seolseong-myun, Icheon-gun. Nitrogen compounds such as NO$_3$-N, NO$_2$-N, NH$_3$-N, and phosphorus compound H$_x$PO$_4$, DO, BOD$_5$, COD, and microbial density were analyzed to evaluate water quality at five test sites designated along the water stream. Tests showed. for example, BOD$_5$ at site 4 was average 9.2mg/l which was about 3~8 times higher than that of observation site 2 and 3, at which most livestock houses were situated. This is a clear evidence that the nutrients of livestock manure illegally discharged to small river can lead to an eutrophication of the river at downstream. A soil absorption system with aeration could be one of alternatives to treat the contaminated wastewater by livestock manure. The place at downstream, inbetween observation site 1 and 2, could be the best construction site for the treatment facility from the standpoint of the overall treatment efficiency, An enclosed composting system can also be regarded as a good alternative for treatment of the sludge which is the by-product of the soil absorption system operation.

• KIEAE Journal
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• 제16권6호
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• pp.83-94
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• 2016

Purpose: A city is regarded as an organic living thing that generates, changes, and fades away in relationship with many components of city. Therefore, a city has its own identity based on its historical trace. Among these elements composing a city, it is a square that makes a city more active and dynamic. Piazza Navona in Rome, Italy has played its role as significant core in the city and has distinctive function from other squares in urban ecological environments. In this study, the distinguishing function and role of Piazza Navona will be defined. Another purpose of study is to figure out what factors of Piazza Navona attracts a lot of diverse people and activities. Method: First, general understanding of function, type, and history of piazza; Second, the historical background of Piazza Navona; Third, site analysis related to surrounding environments; Fourth, architectural characteristic of Piazza Navona in terms of plan and elevation; Fifth, comparing with other representative squares in Rome such as Piazza San Pietro, Piazza del Popolo, and Piazza del Campidoglio in aspects of urban function. Result: Piazza Navona provides both citizen and visitors with an inviting place to embrace all kinds of activities including assembly, annual festival, and daily events. Its functions in the urban environments also involve a tourist attractor as landmark, place for social and cultural interaction, market, and place for meeting and leisure. It is attributed to following factors; historical background as the city center since the first century AD; its location in the center of Rome; enough size and flexibility to accommodate many people and various events; open space enclosed by surrounding buildings; historical baroque structures and sculptures of fountains; synergy effect with commercial and other tourist attractors around Piazza Navona; and comfortable accessibility.

• 건축역사연구
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• 제20권3호
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• pp.59-82
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• 2011

Based on travel literatures written by the Joseon literati, the different picture of seventeenth- and eighteenth-century Buseok monastery from the one today emerges. Not only do the buildings removed from the monastery today reappear, but the quite different way of the monastic operation comes to light. This observation leads to a speculation that the monastery was functionally and spatially divided into two territories; that of the Immeasurable life hall and of the Dharma hall. The Immeasurable life hall's precinct was built at the site open to the west providing a grand vista of mountainous area. This siting, originally having a close relation with the visualization such as the Sixteen contemplation, not simply gave such a special attraction that the first built architectural composition has lasted through the centuries to the late Joseon, but also granted to the Chwiweon pavilion located at the western side of the precinct a special meditative quality. As the monastery has suffered from a number of heavy duties in the Joseon period, the architectural attraction of the precinct was mobilized to promote the monastic identity as the legitimate monastery first built by Uisang, the founder of Hwaeom Buddhsim. Especially, the Chwiweon pavilion offered a mental space so that the literati might form an affirmative attitude toward the monastery and the monks. The Dharma hall's precinct was built based on the direct replication of the architectural layout presented in liturgy books for the Water and Land rite as well as the Vulture Peak rite. This layout is generally called the Court-type enclosed by four buildings, which has been widely fashioned in the late Joseon period. This characteristic gave to the Dharma hall precinct an arbitrary and anonymous quality, which helped not only avoid the tourism of the literati, but also secure the sacrality and ritual efficacy at occasions of Buddhist rites. This division of territories of the monastery can be understood as the strategic reaction from the monks in order to survive in the age of oppression against Buddhism. In result, the identity of Buseok monastery in the late Joseon was established as the Nine-rank sanctuary where Bodhisattvas permanently resided.

• Smart Structures and Systems
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• 제13권4호
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• pp.615-636
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• 2014

Aluminium Foam Sandwich (AFS) panels are becoming always more attractive in transportation applications thanks to the excellent combination of mechanical properties, high strength and stiffness, with functional ones, thermo-acoustic isolation and vibration damping. These properties strongly depend on the density of the foam, the morphology of the pores, the type (open or closed cells) and the size of the gas bubbles enclosed in the solid material. In this paper, the vibrational performances of two classes of sandwich panels with an Alulight(R) foam core are studied. Experimental tests, in terms of frequency response function and modal analysis, are performed in order to investigate the effect of different percentage of porosity in the foam, as well as the effect of the random distribution of the gas bubbles. Experimental results are used as a reference for developing numerical models using finite element approach. Firstly, a sensitivity analysis is performed in order to obtain a limit-but-bounded dynamic response, modelling the foam core as a homogeneous one. The experimental-numerical correlation is evaluated in terms of natural frequencies and mode shapes. Afterwards, an update of the previous numerical model is presented, in which the core is not longer modelled as homogeneous. Mass and stiffness are randomly distributed in the core volume, exploring the space of the eigenvectors.

• Ocean Science Journal
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• 제40권2호
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• pp.67-78
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• 2005

Complex physical, chemical and biological interactions off the Korean coast created several striking patterns in the phytoplankton blooms, which became conspicuous during the measurements of ocean color from space. This study concentrated on analyzing the spatial and temporal aspects of phytoplankton chlorophyll variability in these areas using an integrated dataset from a Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Advanced Very High Resolution (AVHRR) sensor, and Conductivity Temperature Depth (CTD) sensor. The results showed that chlorophyll concentrations were elevated in coastal and open ocean regions, with strong summer and fall blooms, which appeared to spread out in most of the enclosed bays and neighboring waters due to certain oceanographic processes. The chlorophyll concentration was observed to range between 3 and $54\;mg\;m^{-3}$ inside Jin-hae Bay and adjacent coastal bays and 0.5 and $8\;mg\;m^{-3}$ in the southeast sea offshore waters, this gradual decrease towards oceanic waters suggested physical transports of phytoplankton blooms from the shallow shelves to slope waters through the influence of the Tsushima Warm Current (TWC) along the Tsushima Strait. Horizontal distribution of potential temperature $(\theta)$ and salinity (S) of water off the southeastern coast exhibited cold and low saline surface water $(\theta and warm and high saline subsurface water $({\theta}>12^{\circ}C; S>34.4)$ at 75dBar, corroborating TWC intrusion along the Tsushima Strait. An eastward branch of this current was called the East Korean Warm Current (EKWC), tracked with the help of CTD data and satellite-derived sea surface temperature, which often influenced the dynamics of mesoscale anticyclonic eddy fields off the Korean east coast during the summer season. The process of such mesoscale anticyclonic eddy features might have produced interior upwelling that could have shoaled and steepened the nutricline, enhancing phytoplankton population by advection or diffusion of nutrients in the vicinity of Ulleungdo in the East Sea.

• 방송공학회논문지
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• 제18권6호
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• pp.919-926
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• 2013

실내 환경에서 음성 신호는 음향 전달 함수에 의한 반향 신호를 포함한다. 이때 반향의 정도나 반향에 의한 음질 변화를 예측하는 것은 반향 제거 알고리즘 등에서 중요한 정보를 제공한다. 본 논문은 음성 신호의 하모닉 모델링 기법을 이용한 반향 환경에서의 자동 음질 예측 기법을 제안하다. 제안한 방법에서는 반향을 포함하는 음성 신호에 대한 하모닉 모델링 기법이 가능함을 보이고, 모델링된 하모닉 성분과 나머지 성분 사이의 통계적인 비율을 예측한다. 예측된 비율은 일반적인 방 환경에서의 음질 측정 표준 파라미터와 비 교하였다. 실험 결과 제안된 방법은 다양한 반향 환경 (반향 시간 0.2~1.0초)에서 표준 음질 파라미터를 정확하게 예측할 수 있음을 증명하였다.

• 한국컴퓨터정보학회논문지
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• 제16권6호
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• pp.31-39
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• 2011

실내나 밀폐된 축사시설에서는 청정한 환경을 유지하기 위해 온도 습도 그리고 이산화탄소, 메탄가스 등과 같은 환경요인들을 측정하고 관리하여야 한다. 이때 측정된 수치가 관리대상 구간의 정상범위 내에 존재할지라도 시설이나 축적된 배설물과 주변 환경과의 상호작용 등으로 인한 예측치 못한 상황이 발생하면 측정수치는 급격하게 증가 또는 감소하게 된다. 본 논문에서는 이처럼 급격하게 증가하거나 감소하는 비정상 패턴의 변화가 발생할 경우, 이를 인식하여 위해 요소를 미리 제거할 수 있는 조기경고기법(EWarM)을 제안하였다. 그리고 이를 기반으로 한 퍼지 에이전트를 구현하였다. 다양한 상황에서의 성능평가를 통해 조기경고기법(EWarM)에 기반한 퍼지 에이전트가 위해 요소를 제거하는데 유용하다는 것이 입증되었다.

• 한국가스학회지
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• 제24권2호
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• pp.36-43
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• 2020

가스계 소화설비는 경제적으로 매우 유용한 설비이지만 설비를 갖춘 후 장기간 미사용될 경우 용기부식으로 인한 파열 현상과 설비 시스템 작동 오류 등이 나타날 가능성이 있어 큰 위험성을 내재하고 있다. 하지만 소화설비 특성 상, 설비의 정상작동 여부를 확인하기 위한 실험이 불가하여 파열 및 오작동으로 인해 밀폐공간 내에 가스가 일시적으로 방출되면 가스질식으로 인한 큰 인명 피해를 가져올 수 있다. 본 연구에서는 최근 발생한 가스계 소화설비작동 오류로 인한 질식 사망 사고를 바탕으로 사고 메커니즘을 분석하기 위해 실제사고가 발생한 현장에 대해 3D 스캐너와 FLACS를 활용하여 설비 오류로 인한 이산화탄소 가스의 유입경로와 이로 인한 사망 가능성 및 사망에 이르는 시간 등을 추정하였으며 이를 통해 질식사고로 인한 정확한 피해 영향을 평가하고자 한다.