• Title/Summary/Keyword: reliability and safety

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A Study on Assessment of Mothers Perception of a Newborn Baby (어머니의 신생아에 대한 지각사정에 관한 연구)

  • 이자형
    • Journal of Korean Academy of Nursing
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    • v.16 no.3
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    • pp.67-77
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    • 1986
  • The research was carried out in order to assess, at an early stage, the potential barrier in mother-child relationship in the childs' development by using the screening tool. Consequently, after modifying the Neonatal Perception Inventory developed by Broussard and testing its reliability. It has been applied to 152 mothers at the hospital of three universities in Seoul from August 1 to September 30, 1986. The data was analyzed by S.P.S.S. pro-gram and the results were as follows: 1) Mothers perceived the newborn as an individual, and evaluated their baby higher than other babies. 2) Mothers indicated difficulties in their role performance in the fellowing order-bathing, safety, detecting pain or suffering, and feeding. 3) Mothers' perception of a newborn was positive for 75% of the mothers. 4) The factor analysis of the modified tool using principal components analysis and Varimax rotation resulted in the two factors: Factor 1, Baby as an individual: Factor Ⅱ, Performances are required to meet the new-born's needs. 5) The difference in mothers' individual characteristics such as the number of childbirth, the desire to get pregnant or not, the type of deli-very, and the sex of the newborn did not influence on a mothers' perception of her newborn. As seen above, most of the mothers perceived their newborns as able individuals and expressed difficulties involved in taking care of the newborn. Also most of the mothers perceived their babies positively. My point here is, we ought to observe those mothers who perceive their babies negatively, and then compare them with those mothers who perceive their babies extremely positive or extremely negative. In the future, for more comprehensive assessment tool for maternal perception of the newborn, a repetitive verification and modification of this tool is demanded. At the same time, father's perception of the newborn should be included.

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Evaluation of Probabilistic Fracture Mechanics for Reactor Pressure Vessel under SBLOCA (소규모 냉각재 상실사고하의 원자로 압력용기에 대한 확률론적 파괴역학 평가)

  • Kim, Jong Wook;Lee, Gyu Mahn;Kim, Tae Wan
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.4 no.2
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    • pp.13-19
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    • 2008
  • In order to predict a remaining life of a plant, it is necessary to select the components that are critical to the plant life. The remaining life of those components shall be evaluated by considering the aging effect of materials used as well as numerous factors. However, when evaluating reliability of nuclear structural components, some problems are quite formidable because of lack of information such as operating history, material property change and uncertainty in damage models. Accordingly, if structural integrity and safety are evaluated by the deterministic fracture mechanics approach, it is expected that the results obtained are too conservative to perform a rational evaluation of plant life. The probabilistic fracture mechanics approaches are regarded as appropriate methods to rationally evaluate the plant life since they can consider various uncertainties such as sizes and shapes of cracks and degradation of material strength due to the aging effects. The objective of this study is to evaluate the structural integrity for a reactor pressure vessel under the small break loss of coolant accident by applying the deterministic and probabilistic fracture mechanics. The deterministic fracture mechanics analysis was performed using the three dimensional finite element model. The probabilistic integrity analysis was based on the Monte Carlo simulation. The selected random variables are the neutron fluence on the vessel inside surface, the content of copper, nickel, and phosphorus in the reactor pressure vessel material, and initial RTNDT.

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The Communication protocol proposal at Ad-hoc for Water-Treatment (수처리 계측제어망 Ad-hoc 적용시 데이터 신뢰성 확보를 위한 통신 프로토콜 제안)

  • Yu, Chool;Seo, Gang do;Choi, Hong yeol;Hong, Sung taek;Ji, Yu chul
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.10a
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    • pp.984-987
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    • 2013
  • In concept, such as the backup of wired network and disaster prevention network of water treatment measurement and control system, reliability and security of high level of sending and receiving data between the nodes must be ensured in Ad-hoc network construction. Rather than apply the common communication protocols of Ad-hoc network construction during the FA network of closed water treatment facility with the facility of a certain scale is concentrated contrast, and high characteristics of the water treatment system infrastructure, public facilities We have developed a specific protocol another that applies the OTP of communication frame of process control commands and H-ARQ with ZRP by applying the flexibility to time constraints such as precision industrial plants to ensure the safety and property of facility operation.

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Development of Accident Forecasting Models in Freeway Tunnels using Multiple Linear Regression Analysis (다중선형 회귀분석을 이용한 고속도로 터널구간의 교통사고 예측모형 개발)

  • Park, Ju-Hwan;Kim, Sang-Gu
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.11 no.6
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    • pp.145-154
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    • 2012
  • This paper analyzed the characteristics of traffic accidents in all tunnels on nationwide freeways and selected some various independent variables related to accident occurrence in tunnels. The study aims to develop reliable accident forecasting models using the various dependent variables such as the number of accident (no.), no./km, and no./MVK. Finally, reliable multiple linear regression models were proposed in this paper. This study tested the validity verification of developed models through statistics such as $R^2$, F values, multicollinearity, residual analysis. The paper selected the accident forecasting models considering the characteristics of tunnel accidents and two models were finally proposed according to two groups of tunnel length. In the selected models, natural logarithm of ln(no./MVK) is used for the dependent variable and AADT, vertical slope, and tunnel hight are used for the independent variables. The reliability of two models was proved by the comparison analysis between field data and estimating data using RMSE and MAE. These models may be not only effective in evaluating tunnel safety under design and planning phases of tunnel but also useful to reduce traffic accidents in tunnels and to manage the traffic flow of tunnel.

A Study of Interference on Underground Tunnel in Radio Frequency-Communication Based Train Control System (무선 통신기반 열차제어시스템의 지하구간 전파간섭에 대한 연구)

  • Noh, Young-Un;Lee, Jong-Woo
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.1370-1378
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    • 2008
  • In the system necessary for safety such as the train control system, to make train control information be sent correctly is very important. In the case of the system such as RF-CBTC(Radio Frequency-Communication Based Train Control), sometimes failure in correctness of train controlling information may happen because the information is sent throughout wireless transmission between on-board system of a train and wayside transmitter, and then, it is exposed to noises. Of RF-channel interference, there are various forms. Under the environment of mobile telecommunications, adjacent-channel interference and Co-channel interference are in trouble, and under the environment of the wireless LAN, inter-symbol interference is in trouble. Also, the system of the cellular CDMA mobile telecommunication is affected on the RF-channel interference such as Doppler effect, multi-cell interference, and other users' intervention. In this paper, we analyzed the effect of the train control information related to fading, intervention and other noises made in the underground interval and explained the transmission characteristics numerically. Furthermore, we calculated the mean of the error terms by increasing users in the system of the cellular CDMA. As the method for decrease the error term of sent information, we represented the way adjusting the arrangement of antennas, and we did the model related to the system of RF-CBTC in which the location of an antenna is calculated with really measured value of the transmission characteristics and the way confirming reliability of the wireless transmission.

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A Study on Strength Reduction Factor of Pile-soil Interface for Evaluation of Pile Pullout Resistance by Soil Condition (지반조건에 따른 말뚝의 인발저항 평가를 위한 말뚝-지반 경계면 강도감소계수 고찰)

  • You, Seung-Kyong;Shin, Heesoo;Lee, Kwang-Wu;Park, Jeong-Jun;Choi, Choong-Lak;Hong, Gigwon
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.2
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    • pp.45-54
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    • 2019
  • This paper describes the results of finite element analysis (FEA), in order to investigate a characteristics of pile pullout behavior according to the conditions of the relative density and fines content in original ground. In the FEA, a boundary elements and strength reduction factors ($R_{inter}$) on pile-soil interface were applied to simulate appropriately the shear behavior at the pile-soil interface, and then the reliability of numerical analysis method was verified by comparison of FEA results and previous experimental research(You et al., 2018). In addition, a the deformation characteristics at the pile-soil interface and determination method of $R_{inter}$ value was laid out. The results showed that the FEA, based on the analytical model applied in this study simulates appropriately the characteristics of the pile-soil interface by pullout model test of pile. In order to apply the suggested $R_{inter}$ value, it is necessary to consider the condition of the relative density and the fines content in ground.

Implementation of a security system using the MITM attack technique in reverse

  • Rim, Young Woo;Kwon, Jung Jang
    • Journal of the Korea Society of Computer and Information
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    • v.26 no.6
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    • pp.9-17
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    • 2021
  • In this paper, we propose a reversely using the "Man In The Middle Attack" attack technique as a way to introduce network security without changing the physical structure and configuration of the existing network, a Virtual Network Overlay is formed with only a single Ethernet Interface. Implementing In-line mode to protect the network from external attacks, we propose an integrated control method through a micro network security sensor and cloud service. As a result of the experiment, it was possible to implement a logical In-line mode by forming a Virtual Network Overlay with only a single Ethernet Interface, and to implement Network IDS/IPS, Anti-Virus, Network Access Control, Firewall, etc.,. It was possible to perform integrated monitor and control in the service. The proposed system in this paper is helpful for small and medium-sized enterprises that expect high-performance network security at low cost, and can provide a network security environment with safety and reliability in the field of IoT and embedded systems.

Numerical Study of Structural Behavior of Underground Silo Structures for Low-and-Intermediate-level Radioactive Waste Disposal Facility (중저준위 방폐물 처분 사일로 구조물의 구조거동 수치해석 연구)

  • Kim, Sun-Hoon;Kim, Kwang-Jin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.3
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    • pp.183-190
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    • 2022
  • The construction of an underground silo structure was the first stage of erecting the Gyeongju low-and-intermediate-level radioactive waste disposal facility. The facility, completed in 2014, has a scale of 100 000 drums and is currently in operation. The underground silo structure, 25 and 50 m in diameter and height, respectively, consists of cylindrical (for storing waste packages) and dome parts. The dome is divided into lower (connected to the operation tunnel) and upper parts. The wall of the underground silo structure is an approximately 1-m-thick reinforced concrete liner. In this study, finite element analysis was performed for each phase of the construction sequence and operation of the underground silo structure. Two-dimensional axial symmetric finite element analysis was implemented using the SMAP-3D program. Three-dimensional finite element analysis was also performed to examine the reliability of the two-dimensional axial symmetric finite element model. The structural behavior of the underground silo structure was predicted, and its structural safety was examined.

A Study on Non-contact Penetration and Rebound Measurement Device for Quality Control in Driven Piles (말뚝 시공관리를 위한 비접촉식 관입량 측정장치 활용에 관한 연구)

  • Seo, Seunghwan;Kim, Juhyong;Choi, Changho;Chung, Moonkyung
    • Journal of the Korean Geotechnical Society
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    • v.38 no.11
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    • pp.97-106
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    • 2022
  • The domestic auger-drilled pile method generally manages the driving penetration (set) value with the final stage of construction. The penetration value has been estimated by manual measurement for a long time. The automation technology is yet to be applied due to workability and high-cost limitations, despite safety issues and lack of reliability in measured results. In this study, a non-contact pile penetration measurement device was developed. Further, the field performance was verified by comparing the measurements with a conventional automation device. In addition, the on-site field quality control method was analyzed using the penetration measuring device. The field experiments confirmed that more reliable bearing capacity estimation could calculate the dynamic damping coefficient and the modified Hiley formula with the developed device. Furthermore, it can be used for pile construction management from the bearing capacity viewpoint, even for piles not subjected to dynamic load tests. 

Integration of 3D Laser Scanner and BIM Process for Visualization of Building Defective Condition (3D 레이저 스캐닝과 BIM 연동을 통한 건축물 노후 상태 정보 시각화 프로세스)

  • Choi, Moonyoung;Kim, Sangyong;Kim, Seungho
    • Journal of the Korea Institute of Building Construction
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    • v.22 no.2
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    • pp.171-182
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    • 2022
  • The regular assessment of a building is important to understand structural safety and latent risk in the early stages of building life cycle. However, methods of traditional assessment are subjective, atypical, labor-intensive, and time-consuming and as such the reliability of these results has been questioned. This study proposed a method to bring accurate results using a 3D laser scanner and integrate them in Building Information Modeling (BIM) to visualize defective condition. The specific process for this study was as follows: (1) semi-automated data acquisition using 3D laser scanner and python script, (2) scan-to-BIM process, (3) integrating and visualizing defective conditions data using dynamo. The method proposed in this study improved efficiency and productivity in a building assessment through omitting the additional process of measurement and documentation. The visualized 3D model allows building facility managers to make more effective decisions. Ultimately, this is expected to improve the efficiency of building maintenance works.