• Title/Summary/Keyword: Safety evaluation model

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Evaluation of The Seepage Behavior for Reinforced Embankment (보강제체사면의 침투거동평가)

  • 신방웅;안병철
    • Journal of the Korean Society of Safety
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    • v.15 no.1
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    • pp.146-152
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    • 2000
  • To estimate the behavior of reinforced and unreinforced embankment constructed on a impermeable foundation ground, a laboratory model test was performed for two types of soils and water level increasing velocity of a flood period. The experiment models were constructed with slopes of water level is 1.25cm/min, 2.5cm/min each. From model test results, as the slope of reinforced and unreinforced embankment was the slower, the more seepage line rised. In the unreinforced embankment, the rising velocity of water level was the faster, the larger the embankment failure was. And the reinforced embankment with geotextile was the more safe than the unreinforced embankment for seepage force.

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Calculation of Cronbach's Alpha Coefficient, Generalizability Index (GI), and Dependability Index (DI) in the Model Types of Survey Design (서베이 설계 모형별 Cronbach's Alpha 계수와 GI, DI 산출방안)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
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    • 2011.04a
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    • pp.701-705
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    • 2011
  • The paper reviews Cronbaha's coefficient to measure a single source of error. On the contrary to classical measurement theory, the generalizability study can be used in the social survey design to calculate Generalizability Index (GI) and Dependability Index (DI) for measuring multiple sources of errors of behavior evaluation. The study proposes application guidelines to implement R:($A{\times}B$) mixed models that are composed of random factor and fixed factor.

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Sensitivity Evaluation and Approximate Optimization Analysis for Structure Design of Module Hull Type Trimaran Pontoon Boat (모듈 선체형 삼동 폰툰 보트의 구조설계 민감도 평가와 근사 최적화 해석)

  • Bo-Youp Choi;Chang-Ryeon Son;Joon-Sik Son;Min-Ho Park;Chang-Yong Song
    • Journal of the Korean Society of Industry Convergence
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    • v.26 no.6_3
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    • pp.1279-1288
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    • 2023
  • Recently, domestic leisure boats have been actively researching eco-friendly product development to enter the global market. Since the hulls of existing leisure boats are mainly made of fiber reinforced plastic (FRP) or aluminum, design techniques for securing structural safety by applying related materials have been mainly studied. In this study, an initial structural design safety assessment of a trimaran pontoon leisure boat with a modular hull structure and eco-friendly high-density polyethylene (HDPE) material was conducted, and sensitivity evaluation and optimization analysis for lightweight design were performed. The initial structural design safety assessment was carried out by creating a finite element analysis model and applying the loading conditions specified in the ship classification regulation to check whether the specified allowable stresses are satisfied. For the sensitivity evaluation, the influence of stress and weight of each hull structural member was evaluated using the orthogonal array design of experiments method, and an approximate model based on the response surface method was generated using the results of the design of experiments. The optimization analysis set the thickness of the hull structural members as the design variable and considered the optimal design formulation to minimize the weight while satisfying the allowable stress. The algorithm of the optimization analysis applied the Gradient-population Based Optimizer (GBO) to improve the accuracy of the optimal solution convergence while reducing the numerical cost. Through this study, the optimal design of a newly developed eco-friendly trimaran pontoon leisure boat with a weight reduction of 10% was presented.

Assessment of the Navigational Safety Level in the Korean Coastal Waterway (연안해역의 항행 안전성 평가에 관한 연구)

  • 금종수;윤명오;장운재
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.7 no.2
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    • pp.39-48
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    • 2001
  • In recent years, the marine traffic congestion has increased due to the expansion of vessel traffic volume in Korean coastal waterway. Heavy traffic could bring serious marine casualties which cause the loss of human lives, properties and marine pollution in coastal area. The prevention of marine accidents has been a major topic in marin society and various policies and countermeasures have been developed, applied to the industries. VTS(Vessel Traffic Services) is considered as one of effective method to promote marine safety but it needs relatively huge amount of budgets to build and also number of personnels for the operation. Thus prior to establishing the VTS. It should be surveyed the marine traffics, general conditions of waterway including geographical, meteorological characteristics and assessed to find the most reasonable area and places for the system. Therefore this paper aims to develop the method for this evaluation through the hierarchical evaluation structure model in connection with ISM(interpretive structural modeling) and AHP(analytic hierarchy process) methods. The model in this paper is applied to 4 coastal area in Korean waterway as candidates and found that the priority for the needs of VTS should be in order such as Yosu, Wando, Mokpo, Geoje coastal area.

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A Proposal for Risk Evaluation Method of Slope Failure due to Rainfalls (강우 시 사면 붕괴 위험도 평가에 관한 제안)

  • Chae, Jong-Gil;Jung, Min-Su;Tori, Nobuyaki;Okimura, Takashi
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.893-903
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    • 2008
  • A method for predicting surface failures which occur during heavy rainfall on mountain slopes is proposed by using the digital land form model that is obtained by reading altitude on a topographical map at 10m grid point space. A depth of a potential failure layer is assumed at each grid point. In the layer, an infiltrated water movement from cell to cell is modeled in the study (cell is a square of the grid). Infiltrated ground water levels which show the three dimensional effects of a topographical factor in an area can be hourly calculated at every cell by the model. The safety factor of every cell is also calculated every hour by the infinite slope stability analysis method with the obtained infiltrated ground water level. Failure potential delineation is defined here as the time when the safety factor becomes less than unity under the assumptions that effective rainfall is 20mm/h and continues 20 hours.

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Development of a Longitudinal Control Algorithm based on V2V Communication for Ensuring Takeover Time of Autonomous Vehicle (자율주행 자동차의 제어권 전환 시간 확보를 위한 차간 통신 기반 종방향 제어 알고리즘 개발)

  • Lee, Hyewon;Song, Taejun;Yoon, Youngmin;Oh, Kwangseok;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.12 no.1
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    • pp.15-25
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    • 2020
  • This paper presents a longitudinal control algorithm for ensuring takeover time of autonomous vehicle using V2V communication. In the autonomous driving of more than level 3, autonomous systems should control the vehicles by itself partially. However if the driver's intervention is required for functional safety, the driver should take over the control reasonably. Autonomous driving system has to be designed so that drivers can take over the control from autonomous vehicle reasonably for driving safety. In this study, control algorithm considering takeover time has been developed based on computation method of takeover time. Takeover time is analysed by conditions of longitudinal velocity of preceding vehicle in time-velocity plane. In addition, desired clearance is derived based on takeover time. The performance evaluation of the proposed algorithm in this study was conducted using 3D vehicle model with actual driving data in Matlab/Simulink environment. The results of the performance evaluation show that the longitudinal control algorithm can control while securing takeover time reasonably.

Structural Safety of Universal Joint using FEM Simulation (FEM 시뮬레이션을 이용한 유니버설 조인트의 구조안전성)

  • Jung, Jong Yun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.41 no.4
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    • pp.213-219
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    • 2018
  • Mechanical components are to be produced with accurate dimensions in order to function properly in assemblies of a machine. Once designs of mechanical components are created, designers examine the designs by adopting many known experimental methods. A primary test method includes stress and strain evaluation of structural parts. In addition, fatigue test and vibration analysis are an important test method for mechanical components. Real experiments at a laboratory are established when products are manufactured. Since design changes should be done before producing the designs in factories, rapid modifications for new designs are required in production industries. FEM simulation is a proper choice for a design evaluation with speed at a detail stage in design process. This research focuses modeling and mechanical simulation of a mechanical component in order to ensure structural safety. In this paper, a universal joint, being used in driving axels of vehicles, is studied as a target component. A design model is created and tested in some ways by using commercial software of FEM. The designed component is being twisted to transmit heavy power and thus, torsional stress should be under strengths of the component's material. The next is fatigue analysis to convince fatigue cycles to be within the endurance limit of the material. Another test is a vibration analysis for rotational components. This research draws final conclusions from these test analyses and recommends whether the designed model is under safety condition in terms of mechanical structure.

Development of a Test Method for the Evaluation of DNA Damage in Mouse Spermatogonial Stem Cells

  • Jeon, Hye Lyun;Yi, Jung-Sun;Kim, Tae Sung;Oh, Youkyung;Lee, Hye Jeong;Lee, Minseong;Bang, Jin Seok;Ko, Kinarm;Ahn, Il Young;Ko, Kyungyuk;Kim, Joohwan;Park, Hye-Kyung;Lee, Jong Kwon;Sohn, Soo Jung
    • Toxicological Research
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    • v.33 no.2
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    • pp.107-118
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    • 2017
  • Although alternative test methods based on the 3Rs (Replacement, Reduction, Refinement) are being developed to replace animal testing in reproductive and developmental toxicology, they are still in an early stage. Consequently, we aimed to develop alternative test methods in male animals using mouse spermatogonial stem cells (mSSCs). Here, we modified the OECD TG 489 and optimized the in vitro comet assay in our previous study. This study aimed to verify the validity of in vitro tests involving mSSCs by comparing their results with those of in vivo tests using C57BL/6 mice by gavage. We selected hydroxyurea (HU), which is known to chemically induce male reproductive toxicity. The 50% inhibitory concentration ($IC_{50}$) value of HU was 0.9 mM, as determined by the MTT assay. In the in vitro comet assay, % tail DNA and Olive tail moment (OTM) after HU administration increased significantly, compared to the control. Annexin V, PI staining and TUNEL assays showed that HU caused apoptosis in mSSCs. In order to compare in vitro tests with in vivo tests, the same substances were administered to male C57BL/6 mice. Reproductive toxicity was observed at 25, 50, 100, and 200 mg/kg/day as measured by clinical measures of reduction in sperm motility and testicular weight. The comet assay, DCFH-DA assay, H&E staining, and TUNEL assay were also performed. The results of the test with C57BL/6 mice were similar to those with mSSCs for HU treatment. Finally, linear regression analysis showed a strong positive correlation between results of in vitro tests and those of in vivo. In conclusion, the present study is the first to demonstrate the effect of HU-induced DNA damage, ROS formation, and apoptosis in mSSCs. Further, the results of the current study suggest that mSSCs could be a useful model to predict male reproductive toxicity.

Performance evaluation of safety-critical systems of nuclear power plant systems

  • Kumar, Pramod;Singh, Lalit Kumar;Kumar, Chiranjeev
    • Nuclear Engineering and Technology
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    • v.52 no.3
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    • pp.560-567
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    • 2020
  • The complexity of safety critical systems of Nuclear Power Plant continues to increase rapidly due its transition from analog to digital systems. It has thus become progressively more imperative to model these systems prior to their implementation in order to meet the high performance, safety and reliability requirements. Timed Petri Nets (TPNs) have been widely used to model such systems for non-functional analysis. The paper presents a novel methodology for the analysis of the performance metrics using PN modeling. The paper uses the isomorphism property of the TPNs and the Markov chains for the performance analysis of the safety critical systems. The presented methodology has been validated on a Shutdown System of a Nuclear Power Plant.

A Study on the Direction of Developing a Simulator for Performance Evaluation of Pulse Wave Detectors Through a Review of the Development Status of Cardiovascular Simulators (심혈관계 시뮬레이터 개발 동향 분석을 통한 맥파검사용기기 성능평가 시뮬레이터 연구개발 방향 모색)

  • Lee, Ju-Yeon;Kim, Jaeyoung;Go, Dong-Hyun;Lee, Ji-Won;Lee, Tae-Hee;Park, Chang-Won;Lee, Su-Kyoung
    • Journal of Biomedical Engineering Research
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    • v.43 no.3
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    • pp.136-146
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    • 2022
  • In this study, it is intended to provide basic data that can help develop a cardiovascular simulator for performance evaluation of pulse wave detectors by identifying the development status of domestic and overseas cardiovascular simulators. A total of 119 papers were selected by excluding duplicate literature, gray literature, and literature not related to a cardiovascular simulator. Based on the selected literature, the research trend of cardiovascular simulators was analyzed. As a result of analyzing the purpose of the study, most of the simulators were developed to evaluate the hemodynamic properties of artificial hearts and valves. In addition, it was used for simulation evaluation or hemodynamic studies such as pulse wave studies. As a result of analyzing configurations of the simulators, a heart most often consisted of only one left ventricle. For blood vessels, the Windkessel model was most often constructed using chambers and valves. In most studies, blood was reproduced by mixing glycerin and water to reproduce both density and viscosity. In addition, as a result of analysis from the perspective of medical device performance evaluation, simulators for evaluating artificial heart and artificial valves have been studied a lot, whereas simulators for blood pressure, pulse wave, and blood flow devices have been relatively insignificant. Based on the review results, we suggested considerations when developing a simulator for performance evaluations of a pulse wave detector.