• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.13-20
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• 2020

One of the major issues surrounding big data is the availability of massive time-based or telemetry data. Now, the appearance of low cost capture and storage devices has become possible to get very detailed time data to be used for further analysis. Thus, we can use these time data to get more knowledge about the underlying system or to predict future events with higher accuracy. In particular, it is very important to define custom tailored contract offers for many households and businesses having smart meter records and predict the future electricity usage to protect the electricity companies from power shortage or power surplus. It is required to identify a few groups with common electricity behavior to make it worth the creation of customized contract offers. This study suggests big data transformation as a side effect and clustering technique to understand the electricity usage pattern by using the open data related to smart meter and KNIME which is an open source platform for data analytics, providing a user-friendly graphical workbench for the entire analysis process. While the big data components are not open source, they are also available for a trial if required. After importing, cleaning and transforming the smart meter big data, it is possible to interpret each meter data in terms of electricity usage behavior through a dynamic time warping method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.5
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• pp.483-490
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• 2016

In plant industry, sulfur storage tank is made of steel and annular plate is connected with concrete foundation of ring wall type by anchor bolt. Due to keep sulfur at high temperature in tank by coil, sulfur storage tank is expanded larger than another tank stores fluid at room temperature. Generally, structural design of tank foundation is performed analysis with loading of temperature gradient between inner and outer surface, this method can't consider the phenomenon that load is intensively transferred to concrete foundation at anchor bolt. This means that temperature load is underestimated and causes crack of concrete near anchor bolt. In this study, evaluation formula considering temperature load transfer mechanism through anchor bolt is proposed and load acting on concrete foundation is rationally decided. For this purpose, it is analyzed variation of thermal load per various anchor bolt number using finite element model including tank annular plate and anchor bolt. Solution is proposed as specified term combining result of analysis and theoretical solution for evaluating load transferred by anchor bolt. For confirmation of validation of proposed formula, it is applied in design of sulfur storage tank at plant site, it shows that the formula can be practically applied.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.3
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• pp.69-77
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• 2003

This paper presents test results on eight reduced beam section(RBS) steel moment connections. The testing program addressed bolted versus welded web connection and panel zone(PZ) strength as key variables, Specimens with medium PZ strength were designed to promote energy dissipation from both PZ and RBS regions such that the requirement for expensive doublet plates could be reduced. Both strong and medium PZ specimens with a welded web connection were able to provide satisfactory connection rotation capacity for special moment-resisting frames. On the other hand, specimens with a bolted web connection performed poorly due to premature brittle fracture of the beam flange of the weld access hole. If fracture within the beam flange groove weld was avoided using quality welding, the fracture tended to move into the beam flange base metal of the weld access hole. Plausible explanation of a higher incidence of base metal fracture in bolted web specimens was presented. The measured strain data confirmed that the classical beam theory dose not provide reliable shear transfer prediction in the connection. The practice of providing web bolts uniformly along the beam depth was brought into question. Criteria for a balanced PZ strength improves the plastic rotation capacity while reduces the amount of beam distortion ore also proposed.

• The Journal of the Petrological Society of Korea
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• v.15 no.2 s.44
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• pp.72-80
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• 2006

We report new K-Ar ages of volcanic rocks from Ulleung-do and Dok-do islands located at the middle of the Korea Sea; $3.67{\pm}0.40\sim1.89{\pm}0.29$ Ma for the Dok-do and $8.07{\pm}0.39\sim0.51{\pm}0.07$ Ma for the Ulleung-do. Such ages reveal that igneous activities of both Dok-do and Ulleung-do extend longer than previously reported. It is likely that igneous activity of Ulleung-do started as early as $8.07{\pm}0.39$ Ma which is much older than age known currently, and latest eruption and intrusion of trachyte of Dok-do lasted until $1.89{\pm}0.29$ Ma, which overlaps previously reported igneous activity of Ulleung-do. However, it seems that the main volcano-building stage of Ulleung-do started after 2.7 Ma and igneous activities of Dok-do were finished mostly before then, which suggests that Dok-do was farmed before Ulleung-do in the respect of main stages of volcano-building. Such explanation agrees well with the hypothesis that southeastern seamounts, Dok-do and Ulleung-do were sequentially generated by relatively fixed hotspot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.581-586
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• 2018

Cast iron manhole lids cause environmental pollution during the manufacturing process, and the work environment is very poor. In addition, if the height of the manhole cover does not match the height of the road surface, it causes considerable inconvenience and safety problems. This study proposes a height - adjustable steel manhole cover that can replace cast iron manhole covers and easily match the road surface with the upper surface of the manhole cover. Structural analysis was performed to grasp the design variable of the structure of the manhole cover, satisfying the required quality performance. To fabricate a manhole cover that satisfies the required load capacity, the optimal design for the U-shaped reinforcement structure was made. The cylindrical shape of the height adjustment part and the low frame were formed by bending the steel sheet into a circular shape and then welding. Reinforcing bars were also made by bending a steel plate. The height adjustment groove was machined by a CNC milling machine. Four prototypes were fabricated and a load bearing test was carried out, and new manhole cover was made reflecting results of the test. In the load bearing test, there was no breakage of the welded part, and deformation occurred mainly at the contact area between the groove and gusset plate. Deformation of 1 to 2.7mm occurred due to a load of 450kN. On the other hand, after removing the load, there was almost no residual deformation, and the load bearing evaluation was judged to be satisfactory because the manhole cover could be disassembled and reassembled.

• Journal of the Mineralogical Society of Korea
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• v.26 no.4
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• pp.331-342
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• 2013

동아프리카 열곡대는 아라비아반도와 아프리카 북동부의 경계에서 부채꼴 형태로 남쪽으로 뻗은 대단층 함몰지구대이다. 아프리카 판 내부에 발달한 열곡대의 폭은 35~60 km이며 연장은 약 4,000km로 알려져 있다. 열곡대는 에티오피아에서 남서방향으로 발달하다 에티오피아 남부에서 동, 서 및 남서 열곡대로 나누어진다. 이 열곡대는 제3기초 올리고세(30~35 Ma)부터 에티오피아 북부 아파르 침강대를 중심으로 주 에티오피아 열곡대가 형성되고, 남쪽으로 확장되면서 마이오세에 활성화된다. 서부 열곡대는 동아프리카대지의 가장자리와 빅토리아 호의 서편을 따라 발달하며, 고각의 정단층에 의해 특징되는 전형적인 반지구대이다. 동부 열곡대(주 에티오피아 열곡대와 케냐 열곡대)는 30 Ma 전 화산활동과 지구조활동이 시작되었으나, 서부 열곡대는 Albert 호 북부에서 12 Ma 전에, Tanganyika 열곡에서는 7 Ma 전부터 시작되었다. 서부 열곡대의 남서 방향으로 분기된 남서 열곡대는 DR-콩고 남부와 잠비아의 Tanganyika 호에서부터 남서 방향으로 확장되어 보츠와나 Okavango 열곡대와 연결된다. 주 에티오피아 열곡대(MER)의 화산암류와 관련 퇴적암류는 지열, 소다회, 포타쉬(K), 천열수 금, 벤토나이트, 유황 및 부석자원으로 중요한 관련암으로 역할을 한다. 열곡관련 대표적인 광상으로는 Afar 열곡대에 분포하는 Danakhil K-광상과 Megenta 및 Blackrock 천열수 금광상이다. Danakhil K-광상은 제4기 화산활동과 높은 지열류에 의해 열곡대 내 분포하던 소금 선상지(salt fan)에서 증발작용에 의해 형성된 증발형 K-광상으로서 총 자원량은 약 12.6억톤으로 평가되었다. 이 광상에서는 4종의 K-광물인 실바이트, 카날라이트, 포리하라이트, 카이나이트가 산출한다. 아파르 침강대 내 분포하는 대표적인 천열수 금광상은 텐다호 지구대에 위치하는 Megenta 및 Blackrock 광상이다. 제4기에 EMR에서 산성의 과알칼리 화산활동에 의해 열수활동이 초래되어 현재까지도 활동하여 지열대가 형성되고, 저유황형금 광상들이 형성되었다. Megenta 저유황형 금 광상은 2009년 발견되었으며, 현재 영국의 Startex International사에 의해 탐사가 진행 중이다. 지금까지의 탐사 결과 옥수질 규화 변질암 분포지에서 5개의 광체가 분포하며, 그중 Hyena 광체에서는 규화 변질된 열수각력암에서 최고 16.75 g/t의 금 품위가 보고되었다. 동아프리카 열곡대의 서편인 부룬디에 분포하는 Gakara REE 광상은 카보너타이트 유형의 REE 광상이다. 이 광상은 $400km^2$ 면적 내 수 cm부터 수 m까지의 폭을 가지는 맥상 또는 망상세맥상의 광체를 형성한다. 주로 조립의 바스트너사이트와 모나자이트로 구성된다. 바스트너사이트의 형성시기는 $587{\pm}4Ma$인 신원생대로 알려져 있으며, 이 지역에 분포하는 카보너타이트와 알칼리암들이 신원생대에서 신생대까지의 광범위한 연대를 보이는 것은 동일한 구조선을 따라서 일어나는 반복되는 열곡활동으로 해석된다. 또한 REE, U, 인회석 자원의 관련암체로 생각되는 알카리 조면암(네펠린-조면암 포함)과 카보너타이트는 동아프리카 열곡대의 남동부 끝자락인 말라위와 모잠비크에 우세하게 분포한다.

• Journal of Conservation Science
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• v.36 no.5
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• pp.315-325
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• 2020

The Daetongsa temple is the earliest temple to be constructed during the era of the Three Kingdoms in ancient Korea. The main architect, purpose, and name of the temple have been confirmed through ancient literature and archeological materials carved in the Chinese letter, Daetong, excavated around Gongju. However, the location and range of the temple have remained elusive and were discussed in various studies. In this study, we examine the roof tiles obtained from the presumed site of the Daetongsa temple. The tiles were found to contain traces of red paint (red pigments) on their surface and analyzed using nondestructive techniques. The results imply that roof tiles were made using clay tablets and wooden cylinders, with latticed cloth in between. Additionally, some wooden cylinders appeared to comprise numerous wooden plates tied together by strings. The clay tablets used to make the roof tiles were produced from the source clay via the sorting process. The traces of red paint on the surface of the roof tiles were verified to be traditional pigments used for painting wooden buildings. These pigments were extracted from red ocher or red clay (Seokganju), mainly consisting of iron oxide. In the literature, the location of provenance sites for Seokganju is estimated to be far from Gongju. However, the materials for extracting the red pigments were relatively easy to source because most rocks comprised iron oxides. Therefore, it is necessary to discuss the provenance of the red pigments around the presumed site of Daetongsa.

• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.87-96
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• 2004

Application of the soil nailing method is continuously extending in maintaining stable excavations and slopes. However, ground anchor support system occasionally may not be used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then could play important roles to reduce deformations mainly in an upper part of the nailed-soil excavation system as well as to improve local stability. In this study, a newly modified soil nailing technology named as the PSN (Pretension Soil Nailing) is developed to reduce both facing displacements and ground surface settlements in top-down excavation process as well as to increase the global stability. Up to now, the PSN system has been investigated mainly focusing on an establishment of the design procedure. In the present study, laboratory model tests are carried out to investigate the failure mechanism and behavior characteristics of the PSN system. Various results of model tests are also analyzed to provide a fundamental basis for the efficient design.

• The Journal of the Petrological Society of Korea
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• v.9 no.1
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• pp.1-12
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• 2000

The Cretaceous basaltic rocks in Gyeongsang Basin are temporally and spatially dispersed widely in thick sedimentary piles: Chilgog basaltic rock (CGB) and Cheongyongsa basaltic rock (CSB) in the Shindong Group, and Hakbong basaltic rocks (HBB), Osibbong basalt (OSB), Secheondong basaltic rocks (SCB), Haman basaltic rocks (HAB), Hama basaltic rocks (HMB), and Chaeyaksan basaltic rocks (CYB) in the Hayang Group, upwardly in their stratigraphy. Chilgog basaltic rock is merely identified as pebbles in the Shilla Conglomerate and its provenance has not been found, and it is characteristics that the volcanics except Osibbong basalt and Chaeyaksan basaltic rocks are very small in both of their thickness and extension. Petrochemical diversity of the basaltic rocks are revealed; OSB and SCB distributed in the Yeongyang Minor Basin preserve the calc-alkaline natures in major and immobile minor element geochemistry, but CGB, HBB, HAB, and CYB reflect that they might be originated from calc-alkaline basaltic magma of volcanic arc in continental margin area by trace elements and altered to alkaline suites in the viewpoint of their major element geochemistry. Major and trace element geochemistry of CSB and HMB suggests that they may be derived from within -plate alkaline magma contaminated by the upper continental crust, especially in the case of the former.

• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.303-310
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• 2011

To replace a steel box bridge for constructions of medium span bridges in Korea, the Hybrid Truss Bridge (HTB) is being considered as an alternative bridge type. The core technology of HTB is the connection joint that links the concrete slabs and steel truss pipes. Various construction companies in Japan have developed unique connection systems and applied to the real bridge constructions after verifying their performances through the experimental evaluation. In this study, the fatigue test of a hybrid truss girder has been performed in order to verify the newly proposed hinge type connection joint`s static and fatigue capacities. Through this fatigue test results, it is founded that the structural detail to improve the fatigue capacity should be developed. The hinge connection system with circular ribs has been proposed by means of structural finite element analyses. And then the fatigue test for this connection joint has been performed and it is proved that this connection joint has enough fatigue capacity. Finally, it is expected that the hinge connection system with circular ribs developed by in this study can be easily applied to the real bridge.