• Title/Summary/Keyword: Collapse time

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A Study on the Safety Evaluation of the Landing Pier Structure Using FBG Sensor (FBG 센서를 이용한 잔교식 안벽 구조물의 안전성 평가에 대한 연구)

  • Lee, Heung-Su
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.2
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    • pp.44-50
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    • 2019
  • The underwater structures of landing pier are not easy to access and it is difficult to check the damage. Lately, typhoons and earthquakes have occurred frequently, which may cause damage to underwater structures of landing pier. In this study, to prevent collapse of underwater structures and to maintain systematically, the application method of FBG sensors and safety evaluation methods were studied. In order to confirm the application of the FBG sensor to the circular steel pipe used as a pile on the landing pier, we conducted laboratory tests and confirmed that the FBG sensor should be applied by welding. As a result of structural analysis of the landing pier structure, the optimal position of FBG sensor confirmed. The stresses on the dead load were calculated by structural analysis, the stresses on the live load were calculated by using the data obtained from the FBG sensor, and then the stress acting on the pile was calculated by adding the two stresses. The calculated stress was compared with the allowable stress to evaluate the safety of the pile. This study was carried out as a basic study to find a way to evaluate the safety of the landing pier in real time.

A Study on Anxiety Reduction and Transitional object in Infants (유아의 불안감소와 중간대상에 대한 연구)

  • Yoon, Seok-Min
    • Industry Promotion Research
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    • v.6 no.4
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    • pp.39-45
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    • 2021
  • This study presented the role of the counselor's transitional object through literature research, focusing on Winnicott's theory. In the process of development, infants experience anxiety when they move from absolute dependence to relative dependence with their mother. In this way, the counselor's role as an transitional object buffers separation anxiety and depressive anxiety about the loss experience, and mediates from the omnipotent fantasy to the real world. transitional objects are new objects and have a function of contributing to adaptation in reality. And it leads to the stage of separation and individualization through transitional object and transitional phenomena. It can be said that he acquires a sense of the real other that exists in order to create and destroy omnipotent, and to adapt to reality. A good enough mother makes the child's omnipotence meaningful. In this case, the true self helps the infant's weak self to grow and lead him to live his own life. When the mother fails to satisfy the infant's needs, her fantasies and spontaneous impulses are lacking. In other words, when the mother fails to reflect the infant's needs, the infant looks at her mother's mood, giving up her true self and creating a false self. The pathology of the absolute dependence phase is caused by the failure of a good enough mother's empathy and nurturing environment. At this time, the child experiences the collapse of the omnipotence illusion and experiences annihilation anxiety. Therefore, effective counseling can be carried out when providing a comfortable and stable environment by reducing separation anxiety and depressive anxiety of clients through the role of the counselor's transitional object in the counseling field.

Collapse Type and Processes of the Geumosan Caldera in the Southern Gumi, Korea (구미 남부 금오산 칼데라의 함몰 유형과 과정)

  • Hwang, Sang Koo;Son, Young Woo;Seo, Seung Hwan;Kee, Weon-Seo
    • Economic and Environmental Geology
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    • v.54 no.1
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    • pp.35-48
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    • 2021
  • The Gumi basin, situated in the mid-southeastern Yeongnam Massif, has the Cretaceous stratigraphy that is divided into Gumi Formation, andesitic rocks (Yeongamsan Tuff, Busangni Andesite), rhyolitic rocks (Obongni Tuff, Doseongul Rhyolite, Geumosan Tuff) and Intrusives (ring dikes, other dikes) in ascending order. The Geumosan Tuff is composed mostly of many ash-flow tuffs which are associated with Geumosan caldera along with the ring dikes. The caldera is outlined by ring faults and dikes and has about 3.5 × 5.6 km in diameters. The intracaldera volcanics show a downsag structure that is dipped inward in their flow and welding foliations. The caldera block represent an asymmetric subsidence, which drops 350 m in the northern margin and 600 m in the southern one. Based on these data, the Geumosan caldera is geometrically classified as an asymmetric piston subsidence caldera that suggests a single caldera cycle. The caldera reflects the piston subsidence of the caldera block bounded by the outward-dipping ring faults following a voluminous eruption of magma from the chamber. The downsag in the caldera block refers to the downsagging during the initial subsidence at the same time as the full development of the bound fault. In the ring fissures following the sagging, magma was injected due to the overpressure of magma chamber caused by subsidence.

Proposal for Safety Management of Formwork Construction Using IT Technology (IT 기술을 이용한 거푸집 동바리공사 안전관리 제안)

  • Jeon, Kyong-Deck;Shin, Seung-Jung
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.6
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    • pp.93-99
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    • 2020
  • In terms of construction work, the construction cost is lower than the importance of the construction, and since it is demolished after the completion of the construction, it is treated as a relatively small proportion compared to other construction types. Construction engineers who actually worked on the site talk about the safety of the construction work as the most important work of the various processes to ensure the quality and safety of the construction work. However, it is also true that safety management is difficult for temporary construction because various types of temporary materials are installed at various sites at the same time as construction progresses, and the main construction is carried out using them. Safety accidents in construction work are not much different even if they are carried out in temporary construction. The importance and safety of construction work cannot be neglected in view of the recent trend of large-scale construction, multi-purpose, excavation of large-scale underground spaces, and construction trends that are changing to skyscrapers. The purpose of this research is to secure the safety of Dongbar among the temporary materials used in construction work by using IT convergence technology, and to propose safety management to prevent safety accidents in the construction work.

Impacts of stream water quality and fish histopathology by effluents of wastewater treatment plant (하수종말처리장 배출수에 의한 하천 수질 특성 및 어류의 조직병리학적 영향)

  • Kim, Hye-Jin;An, Kwang-Guk
    • Korean Journal of Environmental Biology
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    • v.38 no.4
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    • pp.678-690
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    • 2020
  • In this study, the histological changes of Zacco platypus exposed to discharge from a Wastewater Treatment Plant (WTP), which is a point source, for a long time (2 to 3 years) were compared to the same species at a reference site (Ref.). Overall, tissues displayed various lesions in samples obtained at the point where discharge water from the point source was mixed. In the skin tissue, mucus cells from the epithelial layer expanded to the multilayered epithelium, indicating the immune system was activated. Epithelial cell detachment and proliferation were most prominent in the gills, which may have adversely affected circulation and respiration. Our data suggest immune system collapse was due to stimulation by aquatic substances. Both the fish phase analysis and the water quality analysis demonstrated depreciated conditions at the point source as compared to the reference stream, supporting the histological health evaluation results. These data together suggest a histological approach can also be used to assess water quality, and to an even higher degree when combined with other existing methods. Given the presented evaluation, improvement in the water quality of water discharged from WTP's is required.

Automatic Bee-Counting System with Dual Infrared Sensor based on ICT (ICT 기반 이중 적외선 센서를 이용한 꿀벌 출입 자동 모니터링 시스템)

  • Son, Jae Deok;Lim, Sooho;Kim, Dong-In;Han, Giyoun;Ilyasov, Rustem;Yunusbaev, Ural;Kwon, Hyung Wook
    • Journal of Apiculture
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    • v.34 no.1
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    • pp.47-55
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    • 2019
  • Honey bees are a vital part of the food chain as the most important pollinators for a broad palette of crops and wild plants. The climate change and colony collapse disorder (CCD) phenomenon make it challenging to develop ICT solutions to predict changes in beehive and alert about potential threats. In this paper, we report the test results of the bee-counting system which stands out against the previous analogues due to its comprehensive components including an improved dual infrared sensor to detect honey bees entering and leaving the hive, environmental sensors that measure ambient and interior, a wireless network with the bluetooth low energy (BLE) to transmit the sensing data in real time to the gateway, and a cloud which accumulate and analyze data. To assess the system accuracy, 3 persons manually counted the outgoing and incoming honey bees using the video record of 360-minute length. The difference between automatic and manual measurements for outgoing and incoming scores were 3.98% and 4.43% respectively. These differences are relatively lower than previous analogues, which inspires a vision that the tested system is a good candidate to use in precise apicultural industry, scientific research and education.

CFD-based Fire Accident Impact Analysis in Clean Room for semiconductor PR Process (반도체 PR 공정의 클린룸내 CFD 기반 화재 사고 영향 분석)

  • Chun, Kwang-Su;Yi, Jinseok;Park, Myeongnam
    • Journal of the Korean Institute of Gas
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    • v.25 no.6
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    • pp.35-44
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    • 2021
  • The PR (Photo Resist) process in the semiconductor process is a process that uses a mixture of flammable substances. Due to the process equipment is installed in a clean room and when flammable substances leak, there is a high risk of suffocation, fire, and explosion. It is necessary to analyze the impact of accidents that may occur during operation and to evaluate whether the safety of workers can be guaranteed. In this study, the value of radiant heat and temperature change at the monitor point set up virtual inside the clean room was confirmed through CFD simulation of 10 leak and fire scenarios using the FLACS CFD - Fire Module. A fire that occurs inside a clean room transfers high radiant heat to the inter-story structure, but its scope is quite limited, and it is unlikely that it will collapse in a single fire accident. There was no scenario in which two stairs leading to the exit were exposed to high radiant heat at the same time due to a fire accident, therefore workers were able to escape in case of a fire. In addition, it was confirmed that the level of radiant heat and temperature rise rapidly decreased as they moved downstairs. According to the API 520 standard, workers exposed to 6.31 kW/m2 of radiant heat that workers can withstand for 30 seconds were confirmed that it was possible to sufficiently escape from the inside.

Big Data-based Monitoring System Design for Water Quality Analysis that Affects Human Life Quality (인간의 삶의 질에 영향을 끼치는 수질(물) 분석을 위한 빅데이터 기반 모니터링 시스템 설계)

  • Park, Sung-Hoon;Seo, Yong-Cheol;Kim, Yong-Hwan;Pang, Seung-Peom
    • Journal of Korea Entertainment Industry Association
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    • v.15 no.3
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    • pp.289-295
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    • 2021
  • Today, the most important factor affecting the quality of human life is thought to be due to the environment. The importance of environmental monitoring systems to improve human life and improve welfare as the magnitude of the damage increases year by year due to the rapid increase in the frequency of hail, typhoons, collapse of incisions, landslides, etc. Is increasing day by day. Among environmental problems, problems caused by water quality have a very high proportion, and as there is a growing concern that the scale of damage will increase when water pollution accidents occur due to urbanization and industrialization, the demand for social water safety nets is increasing. have. In the last 5 years, 259 cases of water pollution (Han River 99, Nakdong River 31, Geum River 25, Seomjin River and Yeongsan River 19, and 85 others) have occurred in the four major river basins. Caused damage. Therefore, it is required to establish a water quality environment management strategy system based on big data that can minimize the uncertainty of the water quality environment by expanding the target of water quality management from the current water quality management system centered on the four major rivers to small and medium-sized rivers, tributaries/branches, and reservoirs. In this paper, we intend to construct and analyze a water quality monitoring system based on big data that can present useful water quality environment information by analyzing the water quality information accumulated for a long time.

Development of Series Connectable Wheeled Robot Module (직렬연결이 가능한 소형 바퀴 로봇 모듈의 개발)

  • Kim, Na-Bin;Kim, Ye-Ji;Kim, Ji-Min;Hwang, Yun Mi;Bong, Jae-Hwan
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.5
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    • pp.941-948
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    • 2022
  • Disaster response robots are deployed to disaster sites where human access is difficult and dangerous. The disaster response robots explore the disaster sites prevent a structural collapse and perform lifesaving to minimize damage. It is difficult to operate robots in the disaster sites due to rough terrains where various obstacles are scattered, communication failures and invisible environments. In this paper, we developed a series connectable wheeled robot module. The series connectable wheeled robot module was developed into two types: an active driven robot module and a passive driven robot module. A wheeled robot was built by connecting the two active type robot modules and one passive type robot module. Two robot modules were connected by one DoF rotating joint, allowing the wheeled robot to avoid obstructions in a vertical direction. The wheeled robot performed driving and obstacle avoidance using only pressure sensors, which allows the wheeled robot operate in the invisible environment. An obstacle avoidance experiment was conducted to evaluate the performance of the wheeled robot consisting of two active driven wheeled robot modules and one passive driven wheeled robot module. The wheeled robot successfully avoided step-shaped obstacles with a maximum height of 80 mm in a time of 24.5 seconds using only a pressure sensors, which confirms that the wheeled robot possible to perform the driving and the obstacle avoidance in invisible environment.

Estimation of Employment Creation Center considering Spatial Autocorrelation: A Case of Changwon City (공간자기상관을 고려한 고용창출중심지 추정: 창원시 사례를 중심으로)

  • JEONG, Ha-Yeong;LEE, Tai-Hun;HWANG, In-Sik
    • Journal of the Korean Association of Geographic Information Studies
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    • v.25 no.1
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    • pp.77-100
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    • 2022
  • In the era of low growth, many provincial cities are experiencing population decline and aging. Population decline phenomena such as reduction of productive manpower, reduction of finances, deterioration of quality of life, and collapse of the community base are occurring in a chain and are being pushed to the brink of extinction of the cities. This study aims to propose a methodology to objectively estimate the employment creation centers and setting the basic unit of industrial-centered zoning by applying spatial statistical techniques and GIS for the application of the compact city plan as an efficient spatial management policy in a city with a declining population. In details, based on reviewing previous studies on compact city, 'employment complex index(ECI)' were defined considering the number of workers, the number of settlers, and the area of development land, the employment creation center was estimated by applying the 'Local Moran's I' and 'Getis-Ord's Hot-Spot Analysis'. As a case study, changes in the four years of 2013, 2015, 2017, and 2019 were compared and analyzed for Changwon City. As a result, it was confirmed that the employment creation center is becoming compacted and polycentric, which is a significant result that reflects the actual situation well. This results provide the basic data for functional and institutional territorial governance for the regional revitalization platform, and provide meaningful information necessary for spatial policy decision-making, such as population reduction, regional gross domestic product, and public facility arrangement that can respond to energy savings, transportation plans, and medical and health plans.