• Title/Summary/Keyword: 환경정보시스템

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Development of a complex failure prediction system using Hierarchical Attention Network (Hierarchical Attention Network를 이용한 복합 장애 발생 예측 시스템 개발)

  • Park, Youngchan;An, Sangjun;Kim, Mintae;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.26 no.4
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    • pp.127-148
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    • 2020
  • The data center is a physical environment facility for accommodating computer systems and related components, and is an essential foundation technology for next-generation core industries such as big data, smart factories, wearables, and smart homes. In particular, with the growth of cloud computing, the proportional expansion of the data center infrastructure is inevitable. Monitoring the health of these data center facilities is a way to maintain and manage the system and prevent failure. If a failure occurs in some elements of the facility, it may affect not only the relevant equipment but also other connected equipment, and may cause enormous damage. In particular, IT facilities are irregular due to interdependence and it is difficult to know the cause. In the previous study predicting failure in data center, failure was predicted by looking at a single server as a single state without assuming that the devices were mixed. Therefore, in this study, data center failures were classified into failures occurring inside the server (Outage A) and failures occurring outside the server (Outage B), and focused on analyzing complex failures occurring within the server. Server external failures include power, cooling, user errors, etc. Since such failures can be prevented in the early stages of data center facility construction, various solutions are being developed. On the other hand, the cause of the failure occurring in the server is difficult to determine, and adequate prevention has not yet been achieved. In particular, this is the reason why server failures do not occur singularly, cause other server failures, or receive something that causes failures from other servers. In other words, while the existing studies assumed that it was a single server that did not affect the servers and analyzed the failure, in this study, the failure occurred on the assumption that it had an effect between servers. In order to define the complex failure situation in the data center, failure history data for each equipment existing in the data center was used. There are four major failures considered in this study: Network Node Down, Server Down, Windows Activation Services Down, and Database Management System Service Down. The failures that occur for each device are sorted in chronological order, and when a failure occurs in a specific equipment, if a failure occurs in a specific equipment within 5 minutes from the time of occurrence, it is defined that the failure occurs simultaneously. After configuring the sequence for the devices that have failed at the same time, 5 devices that frequently occur simultaneously within the configured sequence were selected, and the case where the selected devices failed at the same time was confirmed through visualization. Since the server resource information collected for failure analysis is in units of time series and has flow, we used Long Short-term Memory (LSTM), a deep learning algorithm that can predict the next state through the previous state. In addition, unlike a single server, the Hierarchical Attention Network deep learning model structure was used in consideration of the fact that the level of multiple failures for each server is different. This algorithm is a method of increasing the prediction accuracy by giving weight to the server as the impact on the failure increases. The study began with defining the type of failure and selecting the analysis target. In the first experiment, the same collected data was assumed as a single server state and a multiple server state, and compared and analyzed. The second experiment improved the prediction accuracy in the case of a complex server by optimizing each server threshold. In the first experiment, which assumed each of a single server and multiple servers, in the case of a single server, it was predicted that three of the five servers did not have a failure even though the actual failure occurred. However, assuming multiple servers, all five servers were predicted to have failed. As a result of the experiment, the hypothesis that there is an effect between servers is proven. As a result of this study, it was confirmed that the prediction performance was superior when the multiple servers were assumed than when the single server was assumed. In particular, applying the Hierarchical Attention Network algorithm, assuming that the effects of each server will be different, played a role in improving the analysis effect. In addition, by applying a different threshold for each server, the prediction accuracy could be improved. This study showed that failures that are difficult to determine the cause can be predicted through historical data, and a model that can predict failures occurring in servers in data centers is presented. It is expected that the occurrence of disability can be prevented in advance using the results of this study.

Context Sharing Framework Based on Time Dependent Metadata for Social News Service (소셜 뉴스를 위한 시간 종속적인 메타데이터 기반의 컨텍스트 공유 프레임워크)

  • Ga, Myung-Hyun;Oh, Kyeong-Jin;Hong, Myung-Duk;Jo, Geun-Sik
    • Journal of Intelligence and Information Systems
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    • v.19 no.4
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    • pp.39-53
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    • 2013
  • The emergence of the internet technology and SNS has increased the information flow and has changed the way people to communicate from one-way to two-way communication. Users not only consume and share the information, they also can create and share it among their friends across the social network service. It also changes the Social Media behavior to become one of the most important communication tools which also includes Social TV. Social TV is a form which people can watch a TV program and at the same share any information or its content with friends through Social media. Social News is getting popular and also known as a Participatory Social Media. It creates influences on user interest through Internet to represent society issues and creates news credibility based on user's reputation. However, the conventional platforms in news services only focus on the news recommendation domain. Recent development in SNS has changed this landscape to allow user to share and disseminate the news. Conventional platform does not provide any special way for news to be share. Currently, Social News Service only allows user to access the entire news. Nonetheless, they cannot access partial of the contents which related to users interest. For example user only have interested to a partial of the news and share the content, it is still hard for them to do so. In worst cases users might understand the news in different context. To solve this, Social News Service must provide a method to provide additional information. For example, Yovisto known as an academic video searching service provided time dependent metadata from the video. User can search and watch partial of video content according to time dependent metadata. They also can share content with a friend in social media. Yovisto applies a method to divide or synchronize a video based whenever the slides presentation is changed to another page. However, we are not able to employs this method on news video since the news video is not incorporating with any power point slides presentation. Segmentation method is required to separate the news video and to creating time dependent metadata. In this work, In this paper, a time dependent metadata-based framework is proposed to segment news contents and to provide time dependent metadata so that user can use context information to communicate with their friends. The transcript of the news is divided by using the proposed story segmentation method. We provide a tag to represent the entire content of the news. And provide the sub tag to indicate the segmented news which includes the starting time of the news. The time dependent metadata helps user to track the news information. It also allows them to leave a comment on each segment of the news. User also may share the news based on time metadata as segmented news or as a whole. Therefore, it helps the user to understand the shared news. To demonstrate the performance, we evaluate the story segmentation accuracy and also the tag generation. For this purpose, we measured accuracy of the story segmentation through semantic similarity and compared to the benchmark algorithm. Experimental results show that the proposed method outperforms benchmark algorithms in terms of the accuracy of story segmentation. It is important to note that sub tag accuracy is the most important as a part of the proposed framework to share the specific news context with others. To extract a more accurate sub tags, we have created stop word list that is not related to the content of the news such as name of the anchor or reporter. And we applied to framework. We have analyzed the accuracy of tags and sub tags which represent the context of news. From the analysis, it seems that proposed framework is helpful to users for sharing their opinions with context information in Social media and Social news.

A Study on the Necessity of Making Online Marketplace for the Korean Animation Industry (국내 애니메이션 산업의 온라인 마켓플레이스 구축 필요성 연구)

  • Han, Sang-Gyun
    • Cartoon and Animation Studies
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    • s.24
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    • pp.223-246
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    • 2011
  • Today, cultural content industry could be defined to service business rather than manufacturing business because of its own trait. Also, it has the realistic restriction that it can't hold the dominant position in the market competition when it can't provide consumers satisfaction regardless of its quality or degree of completion. In other word, it can only expect great success when the business plan and the activities get the perfect balance with its best quality and perfect of completion. As the result, it emphasizes the importance of business competition in the global market. In briefly, there is no doubt that the creativeness of content is very important in the cultural content industry but in the future, making system to maintain the distribution process and share the profits fairly will be taken more important role. Especially, animation genre has the feature, which compares to other genres, such as film or TV drama, would be free from cultural barriers, and it is a great advantage. So to speak, animation can get little influence from cultural discount. However, Korean animation can't use the advantage properly for the foreign distribution because of its poor infrastructure and short of professional human resources. For those reasons, it has been needed to set up the realistic and specific action plan to overcome the situation. Therefore, considering those needs and the situations of Korean animation facing, making B2B online marketplace could be a great solution. The online marketplace stands for taking more efficient and broad distribution channel instead of the passive way, which we have now. If we have the B2B online marketplace, we can share all the information about the Korean animation with the potential customers whom live outside of Korea at real time. It also could be use to the windows of multiple distribution, which can make additional profits and activate the optional markets for the Korean animation. Through the method, Korean animation would be expected to get the higher international competitiveness, and it would be developed in quality and quantity of the business. Finally, it would be a great chance to Korean animation, which can get the unique brand power by improving the backward distribution circumstances.

A Study on Cold Water Damage to Marine Culturing Farms at Guryongpo in the Southwestern Part of the East Sea (경북 구룡포 해역에서의 냉수 발생과 어장 피해)

  • Lee, Yong-Hwa;Shim, JeongHee;Choi, Yang-ho;Kim, Sang-Woo;Shim, Jeong-Min
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.6
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    • pp.731-737
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    • 2016
  • To understand the characteristics and strength of the cold water that has caused damage to marine-culturing farms around Guryongpo, in the southwestern part of Korea, surface and water column temperatures were collected from temperature loggers deployed at a sea squirt farm during August-November 2007 and from a Real-time Information System for Aquaculture environment operated by NIFS (National Institute of Fisheries Science) during July-August 2015 and 2016. During the study period, surface temperature at Guryongpo decreased sharply when south/southwestern winds prevailed (the 18-26th of August and 20-22nd of September 2007 and the 13-15th of July 2015) as a result of upwelling. However, the deep-water (20-30m) temperature increased during periods of strong north/northeasterly winds (the 5-7th and 16-18th of September 2007) as a result of downwelling. Among the cold water events that occurred at Guryongpo, the mass death of cultured fish followed strong cold water events (surface temperatures below $10^{\circ}C$) that were caused by more than two days of successive south/southeastern winds with maximum speeds higher than 5 m/s. A Cold Water Index (CWI) was defined and calculated using maximum wind speed and direction as measured daily at Pohang Meteorological Observatory. When the average CWI over two days ($CWI_{2d}$) was higher than 100, mass fish mortality occurred. The four-day average CWI ($CWI_{4d}$) showed a high negative correlation with surface temperature from July-August in the Guryongpo area ($R^2=0.5$), suggesting that CWI is a good index for predicting strong cold water events and massive mortality. In October 2007, the sea temperature at a depth of 30 m showed a high fluctuation that ranged from $7-23^{\circ}C$, with frequency and spectrum coinciding with tidal levels at Ulsan, affected by the North Korean Cold Current. If temperature variations at the depth of fish cages also regularly fluctuate within this range, damage may be caused to the Guryongpo fish industry. More studies are needed to focus on this phenomenon.

A study on the developmental plan of Alarm Monitoring Service (기계경비의 발전적 대응방안에 관한 연구)

  • Chung, Tae-Hwang;So, Seung-Young
    • Korean Security Journal
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    • no.22
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    • pp.145-168
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    • 2010
  • Since Alarm Monitoring Service was introduced in Korea in 1981, the market has been increasing and is expected to increase continually. Some factors such as the increase of social security need and the change of safety consciousness, increase of persons who live alone could be affected positively on Alarm Monitoring Service industry. As Alarm Monitoring Service come into wide use, the understanding of electronic security service is spread and consumer's demand is difficult, so consideration about new developmental plan is need to respond to the change actively. Electronic security system is consist of various kinds of element, so every element could do their role equally. Alarm Monitoring Service should satisfy consumer's various needs because it is not necessary commodity, also electronic security device could be easily operated and it's appearance has to have a good design. To solve the false alarm problem, detection sensor's improvement should be considered preferentially and development of new type of sensor that operate dissimilarly to replace former sensor is needed. On the other hand, to settle the matter that occurred by response time, security company could explain the limit on Alarm Monitoring System to consumer honestly and ask for an understanding. If consumer could be joined into security activity by security agent's explanation, better security service would be provided with mutual confidence. To save response time the consideration on the introduction of GIS(Global Information System) is needed rather than GPS(Global Positioning System). Although training program for security agents is important, several benefits for security agents should be considered together. The development of new business model is required for preparation against market stagnation and the development of new commodity to secure consumer for housing service rather than commercial facility service. for the purpose of those, new commodity related to home-network system and video surveillance system could be considered, also new added service with network between security company and consumer for a basis is to be considered.

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Entre l' espace sculptural et, l' espace architectural (조각공간과 건축공간의 관계)

  • Lee Bong-Soon
    • Journal of Science of Art and Design
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    • v.5
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    • pp.175-216
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    • 2003
  • 시각이 아닌 오감체계에 관계하는 때문에 현대미술은 외관만으로 이루어지지 않는다. 곧 예술 작품들은 하나의 장소를 관객에게 제공하여, 심리적, 물리적, 또는 예술이 존재여부에 관한 갖가지 질문들을 제기한다. 모든 예술 작품은 메시지를 담고 있다. 이러한 관점에서 개념 또는 아이디어에 우선하는 현대미술은 그들의 메시지를 전달하기 위해 우리의 사회적 배경과 보편성을 간과할 수 없다. 우리의 물체 인식은 결국 우리의 경험체계를 통해서 이루어진다고 간주하면, 현대미술의 새로운 형태는 보편적 특질들이 그 특질들 이상의 상태로 보여지도록 유도한다. 이러한 창조 행위의 시작은 현대인간의 문화 읽기이며 문화는 인간과 자연의 긴밀한 관계 속에서 이루어진다. 역사는 지나간 시간을 기록한 것이며, 이 또한 우리의 지식과 정보 체계에 속한다. 회화가 평면에 입체감을 표현하는 것과는 달리 조각은 자연 속, 즉 실재공간 속에 있는 모든 것을 표현하기 때문에 시각(visible) 이외에도 촉각(tangible)이 관여하게 된다. 조각의 특수성은 촉각(tangible)이 우선하는 것이다. 그러나 시각과 촉각은 매우 적극적으로 미학적 경험에 참여하는 감각으로 이들을 서로 분리하여 생각하기가 무척 힘들다. 왜냐하면 어떤 경험에 있어서 기억연합 또는 감각 연합에 의해 하나의 감각이 다른 여러 감각을 촉발하여 연쇄반응 혹은 '형태 Gestalt'를 이루기 때문이다. 대부분의 근대 조각 작품들은 조각대 위에 고정되어 있는 구상 형태를 지녔기 때문에 조각작품 자체가 지닌 외적 형태와 그 자체내의 공간이 더욱 중요한 역할을 하게 된다. 말하자면 미로의 비너스 조각은 대리석과 비너스 형태의 결합이다. 때문에 관객은 그 주변을 돌면서 우리 신체의 내적 공간과 시각에 의존하면서 그 작품의 중량감, 양감, 형태 등의 특질과 만나게 된다. 그러나 현대 추상조각과 개념조각은 이보다 좀 더 확장된 공간을 제시한다. 이것은 현대조각이 건축개념을 수용한 때문이며, 그것이 때로는 안 쪽에서 때로는 바깥 쪽에서 그 형태를 결정하며, 보고 듣고 느끼고 만져지고 왕래하는 등의 인식 영역인 관객의 오감체계에 직접적으로 관계하기 때문이다. 우리는 건축 공간에서, 시각 외에도 청각이나 촉각을 통해 지각한다. 대강 요약하자면 공간은 객관적 상태이기보다는 인식영역의 주관성을 통해 받아들여진 우리가 지나쳐온 것들이나 체험된 공간이다. 여기서 '받아들여지는' 일은 과거 경험들의 주체들, 언어와 문화에 의해서 이루어져야 한다. 건물, 즉 둘러싸고 있는 공간은 중앙이 아니다. 중앙은 바로 나, 둘러싸여진 나이다 나는 나의 동작에 따라 그 공간의 시스템을 변화시킬 수 있는 유동적인 중심이다 (이때의 나는 위치의 축을 변화시키는 것이 아니라, 그들을 탐색하는 것이다). 작품이 대형화되면서 이러한 건축공간개념이 현대 조각가들의 작품개념에 이용되었다고 본다. 현대미술에서 In situ작업과 특정한 장소를 위한 기획되어진 최근의 프로젝트 작업들은 대형화되어있으며, 건축에서처럼 특정한 장소를 만들어낸다. 로잘린드 크라우스(Rosalind Krauss)는 또한 '조각영역의 확장 (La sculpture dans le champ elargi)'에서 현대조각이 건축과 환경의 영역을 침범하고 있음을 지적한다. 그녀에 의하면, 1960년대 이후의 현대조각은 이러한 탈 귀속성과 조각의 자율성을 획득함으로써 조각은 건축물이 아니면서 건축물 주변에 위치하거나 풍경이 아니면서 풍경 안에 자리잡게 되었다. 이와 같이 현대의 대형조각 작품들 - 예를 들어 대형화된 미니별 조각이나 개념미술, 또는 대지예술 등 -은 풍경의 실재가 아니기 때문에 환경으로부터 구분된다고 언급하고 있다. 이들 조각은 더 이상 만져지는 실체이거나 점유하는 공간의 상징언어를 지닌 조각의 범주에 한정되지 않게 된다. 조각과 건축의 공간인식을 인체의 크기와 관련하여 보면, 메를로 퐁티(Merleau-Ponty)의 '지각의 현상학' 은 우리가 논하는 작품의 공간체계를 분석하는데 지침표가 되어준다. 메를로 퐁티가 말하는 지각은 정신에 의해서만 이루어지는 것이 아니며, 몸과 함께 이루어지는 현상이다. 지각은 우리가 부단히 눈을 움직이고 만지고 냄새를 맡고 주변을 돌아 다니면서 세계와의 직접적인 접촉을 통해 이루어 진다. 몸의 움직임을 통하여 나타나는 신체적 표현은 몸 자체가 원천적으로 지향적 활동의 주체로서 파악되는 한 이미 항상(恒常, constant) 의미 현상을 지니다. 우리의 지각이 움직이는 몸의 지향 활동을 통해 이루어진다는 것은 우리의 몸의 지향활동이 의식에 선행함을 의미한다. 몸의 움직임은 의식의 의도를 표현할 때에만 의미를 나타내는 기호가 되는 것이 아니라, 이미 그 자체가 살아있는 표현이다. 우리의 몸짓, 표정은 우리 의식이 의도하기 전에 이미 의미가 담겨있다. 몸은 그 자체가 기호(Signe)적이다. 결국. 메를로 퐁티에게서 세상(le monde entier)은 그 자신이 주체가 되어 인식한다, 그리고 이 인식 구조에는 우리의 몸이 구심점(le point centripete)이 된다. 만약 우리가 이러한 메를로 퐁티의 개념을 염두에 둔다면, 예술작품의 특성에 매우 중요한 역할을 하고 있는 재료와 크기를 이해할 수 있을 것이다.

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A Comparison of Single and Multi-matrix Models for Bird Strike Risk Assessment (단일 및 다중 매트릭스 모델의 비교를 통한 항공기-조류 충돌 위험성 평가 모델 분석)

  • Hong, Mi-Jin;Kim, Myun-Sik;Moon, Young-Min;Choi, Jin-Hwan;Lee, Who-Seung;Yoo, Jeong-Chil
    • Korean Journal of Environment and Ecology
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    • v.33 no.6
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    • pp.624-635
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    • 2019
  • Bird strike accidents, a collision between aircraft and birds, have been increasing annually due to an increasing number of aircraft operating each year to meet heavier demand for air traffic. As such, many airports have conducted studies to assess and manage bird strike risks effectively by identifying and ranking bird species that can damage aircraft based on the bird strike records. This study was intended to investigate the bird species that were likely to threaten aircraft and compare and discuss the risk of each species estimated by the single-matrix and multi-matrix risk assessment models based on the Integrated Flight Information Service (IFIS) data collected in Gimpo, Gimhae and Jeju Airports in South Korea from 2005 to 2013. We found that there was a difference in the assessment results between the two models. The single-matrix model estimated 2 species and 6 taxa in Gimpo and Gimhae Airports and 2 species and 5 taxa in Jeju Airport to have the risk score above "high," whereas the multi-matrix model estimated 3 species and 5 taxa in Gimpo Airport, 4 species and 5 taxa in Gimhae Airport, and 2 species and 3 taxa in Jeju Airport to have the risk score above "very high." Although both models estimated the similar high-risk species in Gimpo and Gimhae Airports, there was a significant difference in Jeju Airport. Gimpo and Gimhae Airports are near the estuary of a river, which is an excellent habitat for large and heavy waterbirds. On the other hand, Jeju Airport is near the coast and the city center, and small and light bird species are mostly observed. Since collisions with such species have little effect on aircraft fuselage, the impact of common variables between the two models was small, and the additional variables caused a significant difference between the estimation by the two models.

Consumers Perceptions on Monosodium L-glutamate in Social Media (소셜미디어 분석을 통한 소비자들의 L-글루타민산나트륨에 대한 인식 조사)

  • Lee, Sooyeon;Lee, Wonsung;Moon, Il-Chul;Kwon, Hoonjeong
    • Journal of Food Hygiene and Safety
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    • v.31 no.3
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    • pp.153-166
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    • 2016
  • The purpose of this study was to investigate consumers' perceptions on monosodium L-glutamate (MSG) in social media. Data were collected from Naver blogs and Naver web communities (Korean representative portal web-site), and media reports including comment sections on a Yonhap news website (Korean largest news agency). The results from Naver blogs and Naver web communities showed that it was primarily mentioned MSG-use restaurant reviews, 'MSG-no added' products, its safety, and methods of reducing MSG in food. When TV shows on current affairs, newspaper, or TV news reported uses and side effects of MSG, search volume for MSG has increased in both PC and mobile search engines. Search volume has increased especially when TV shows on current affairs reported it. There are more periods with increased search volume for Mobile than PC. Also, it was mainly commented about safety of MSG, criticism of low-quality foods, abuse of MSG, and distrust of government below the news on the Yonhap news site. The label of MSG-no added products in market emphasized "MSG-free" even though it is allocated as an acceptable daily intake (ADI) not-specified by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). When consumers search for MSG (monosodium L-glutamate) or purchase food on market, they might perceive that 'MSG-no added' products are better. Competent authorities, offices of education and local government provide guidelines based on no added MSG principle and these policies might affect consumers' perceptions. TV program or news program could be a powerful and effective consumer communication channel about MSG through Mobile rather than PC. Therefore media including TV should report item on monosodium L-glutamate with responsibility and information based on scientific background for consumers to get reliable information.

17O Solid-State NMR Study of the Effect of Organic Ligands on Atomic Structure of Amorphous Silica Gel: Implications for Surface Structure of Silica and Its Dehydration Processes in Earth's Crust (유기 리간드와 비정질 실리카겔의 상호 작용에 대한 17O 고상핵자기공명 분광분석 연구: 실리카 표면 구조 및 지각의 탈수반응에 대한 의의)

  • Kim, Hyun Na;Lee, Sung Keun
    • Journal of the Mineralogical Society of Korea
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    • v.25 no.4
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    • pp.271-282
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    • 2012
  • We explore the effect of removal of organic ligand on the atomic configurations around oxygen in hydroxyl groups in amorphous silica gel (synthesized through hydrolysis of $SiCl_4$ in diethyl-ether) using high resolution $^{17}O$ solid state NMR spectroscopy. $^1H$ and $^{29}Si$ MAS NMR spectra for amorphous silica gel showed diverse hydrogen environments including water, hydroxyl groups (e.g., hydrogen bonded silanol, isolated silanol), and organic ligands (e.g., alkyl chain) that may interact with surface hydroxyls in the amorphous silica gel, for instance, forming silica-organic ligand complex (e.g., Si-$O{\cdots}R$). These physically and chemically adsorbed organic ligands were partly removed by ultrasonic cleaning under ethanol and distilled water for 1 hour. Whereas $^{17}O$ MAS NMR spectra with short pulse length ($0.175{\mu}s$) at 9.4 T and 14.1 T for as-synthesized amorphous silica gel showed the unresolved peak for Si-O-Si and Si-OH structures, the $^{17}O$ MAS NMR spectra with long pulse length ($2{\mu}s$) showed the additional peak at ~0 ppm. The peak at ~0 ppm may be due to Si-OH structure with very fast relaxation rate as coupled to liquid water molecules or organic ligands on the surface of amorphous silica gel. The observation of the peak at ~0 ppm in $^{17}O$ MAS NMR spectra for amorphous silica gel became more significant as the organic ligands were removed. These results indicate that the organic ligands on the surface of amorphous silica gel interact with oxygen atoms in Si-OH and provide the information about atomic structure of silanol and siloxane in amorphous silica gel. The current results could enhance the understanding of dehydration mechanism of diverse silicates, which is known as atomic scale origins of intermediate depth (approximately, 70~300 km) earthquakes in subduction zone.

Interannual and Seasonal Variations of Water Quality in Terms of Size Dimension on Multi-Purpose Korean Dam Reservoirs Along with the Characteristics of Longitudinal Gradients (우리나라 다목적댐 인공호들의 규모에 따른 연별.계절별 수질변이 및 상.하류간 종적구배 특성)

  • Han, Jeong-Ho;Lee, Ji-Yeoun;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.43 no.2
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    • pp.319-337
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    • 2010
  • Major objective of this study was to determine interannual and seasonal water quality along with characteristics of longitudinal gradients along the reservoir axis of the riverine zone (Rz)-to-lacustrine zone (Lz). Water quality dataset of five years during 2003~2007 used here were obtained from Ministry of Environment, Korea and ten physical, chemical and biological parameters were analyzed in the study. Similarity analysis, based on moropho-hydrological variables of reservoir surface area, watershed area, total inflow, and outflow, showed that the reservoirs were categorized as three groups of large-dam reservoirs (Chungju Reservoir, Daecheong Reservoir and Soyang Reservoir), mid-size reservoirs (Andong Reservoir, Yongdam Reservoir, Juam Reservoir and Hapcheon Reservoir), and small-size reservoirs (Hoengseong Reservoir and Buan Reservoir). According to the data comparison of high-flow year (2003) vs. lowflow year (2005), dissolved oxygen (DO), pH, biological oxygen demand (BOD), suspended solids (SS), total nitrogen (TN), total phosphorus (TP), chlorophyll-a (CHL) and electrical conductivity (EC) declined along the longitudinal axis of Rz to Lz and water transparency, based on Secchi depth (SD), increased along the axis. These results indicate that transparency was a function of Values of pH, DO, SS, SD, and EC at each site were greater in the low-flow year (2005) than the high-flow year (2003), whereas values of BOD, COD, TN, TP and CHL were greater in the high-flow year (2003). When values of TN, TP, CHL and SD in nine reservoirs were compared in the three zones of Rz, Tz, and Lz, values of TN, TP and CHL declined along longitudinal gradients and SD showed the opposite due to the sedimentation processes from the water column. Values of TN were not statistically correlated with TP values. The empirical linear models of TP-CHL and CHL-SD showed significant (p<0.05, $R^2$>0.04). In the mid-size reservoirs, the variation of CHL was explained ($R^2$=0.2401, p<0.0001, n=239) by the variation of TP. The affinities in the correlation analysis of mid-size reservoirs were greater in the CHL-SD model than any other empirical models, and the CHL-SD model had an inverse relations. In the meantime, water quality variations was evidently greater in Daecheong Reservoir than two reservoirs of Andong Reservoir and Hoengseong Reservoir as a result of large differences of water quality by long distance among Rz, Tz and Lz.