• Title/Summary/Keyword: periodic data

Search Result 911, Processing Time 0.036 seconds

Application of Probabilistic Fracture Mechanics Technique Using Monte Carlo Simulation (몬테카를로 시뮬레이션을 이용한 확률론적 파괴역학 수법의 적용성 검토)

  • Lee, Joon-Seong;Kwak, Sang-Log;Kim, Young-Jin
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.18 no.10
    • /
    • pp.154-160
    • /
    • 2001
  • For major structural components periodic inspections and integrity assessments are needed for the safety. However, many flaws are undetectable because sampling inspection is carried out during in-service inspection. Probabilistic integrity assessment is applied to take into consideration of uncertainty and variance of input parameters arise due to material properties and undetectable cracks. This paper describes a Probabilistic Fracture Mechanics(PFM) analysis based on the Monte Carlo(MC) algorithms. Taking a number of sampling data of probabilistic variables such as fracture toughness value, crack depth and aspect ratio of an initial surface crack, a MC simulation of failure judgement of samples is performed. for the verification of this analysis, a comparison study of the PFM analysis using a commercial code, mathematical method is carried out and a good agreement was observed between those results.

  • PDF

Experimental and Numerical Flow Visualization on Detailed Flow Field in the Post-surgery Models for the Simulation of the Inferior Turbinectomy (하비갑개 수술 후 비강 모델 내의 세부 유동장의 실험 및 전산 유동가시화)

  • Chang, Ji-Won;Heo, Go-Eun;Kim, Sung-Kyun
    • Journal of the Korean Society of Visualization
    • /
    • v.9 no.3
    • /
    • pp.65-70
    • /
    • 2011
  • Three major physiological functions of nose can be described as air-conditioning, filtering and smelling. Detailed knowledge of airflow characteristics in nasal cavities is essential to understanding of the physiological and pathological aspects of nasal breathing. In our laboratory, a series of experimental investigations have been conducted on the airflows in normal and abnormal nasal cavity models by means of PIV under both constant and periodic flow conditions. In this work, more specifically experimental and numerical results on the surgically modified inferior turbinate model were presented. With the high resolution CT data and a careful treatment of the model surface under the ENT doctor's advice yielded quite sophisticated cavity models for the PIV experiment. Physiological nature of the airflow was discussed in terms of velocity distribution and vortical structure for constant inspirational flow. Since the inferior and middle turbinate are key determinants of nasal airflow, the turbinectomy obviously altered the main stream direction. This phenomenon may cause local changes in physiological function and the flow resistance.

A Study on the Vibration Characteristics of a Head-Feeding Combine by Spectral Analysis (스펙트럼 해석에 의한 자탈형 콤바인의 진동 특성 고찰)

  • ;井上英二
    • Journal of Biosystems Engineering
    • /
    • v.26 no.1
    • /
    • pp.11-20
    • /
    • 2001
  • Experiments under the stationary and harvesting condition, were performed in order to investigate the vibration characteristics of a head-feeding combine. 6 degrees of freedom components of acceleration at the location of the center of the gravity, and 3 degrees of freedom components of acceleration at the location of the operator seat were measured independently. The vibration characteristics of the combine were estimated with the power spectral density of the time series data of accelerations. From this research, the following results were obtained. 1. Vibration of a head-feeding combine under the stationary condition(engine, thresher and cutter are driven without harvesting) is mainly influenced by the engine. Further, 1/3, 1/2 (sub-harmonic) frequency components of the engine are observed besides engine driving frequency component(45Hz). 2. Vibration of a head-feeding combine under the harvesting condition is influenced by the engine, threshing unit and driving unit. Namely, some kinds of vibration frequency components in harvesting are observed compared with stationary condition. Further, sub-harmonic frequency components of the engine are observed besides engine driving frequency component as same as stationary condition. From these results, it may be concluded that vibration of a head-feeding combine is characteristics of semi-periodic and nonlinear vibration.

  • PDF

Diminution of Current Measurement Error for Vector Controlled AC Motor Drives (교류전동기 벡터제어를 위한 전류 측정오차의 저감에 관한 연구)

  • Jung Han-Su;Kim Jang-Mok;Kim Cheul-U;Choi Cheol
    • Proceedings of the KIPE Conference
    • /
    • 2004.11a
    • /
    • pp.32-36
    • /
    • 2004
  • In order to achieve high performance vector control, it is essential to measure accurate ac current. The errors generated from current path are inevitable, and they could be divided into two categories: offset error and scaling error. The current data including these errors cause periodic speed ripples which are one and two times of stator electrical frequency respectively. Since these undesirable ripples bring about bad influences to motor driving system, a compensation algorithm must be needed in the control algorithm of the motor drive. In this paper, a new compensation algorithm is proposed. The signal of the integrator output of the d-axis current regulator is chosen and processed to compensate the current measurement errors. The compensation of the current measurement errors is easily implemented to smooth the signal of the integrator output of the d-axis current regulator by subtracting the DC offset value or rescaling the gain of the hall sensor. Therefore, the proposed algorithm has several features: the robustness of the variation of the mechanical parameters, the application of the steady and transient state, the easy implementation, and less computation time.

  • PDF

Verification of the Validity of Moisture Transfer Model for Prediction of Indoor Moisture Generation Rate (실내 수증기 발생량 예측을 위한 습기 전달 모델의 검증에 관한 연구)

  • Lee, Dong-Kweon;Kim, Eui-Jong;Choi, Won-Ki;Suh, Seung-Jik
    • Journal of the Korean Solar Energy Society
    • /
    • v.26 no.1
    • /
    • pp.41-47
    • /
    • 2006
  • Moisture in a building is one of the most important variables influencing building performance, human health, and comfort of indoor environment. However, there are still lacks in the knowledge of understanding the moisture problem well and controlling moisture. Accordingly, in order to provide the fundamental data to control moisture contents in the indoor air, this study was to predict moisture contents transferred through building envelopes and indoor moisture generation rate. Moisture transfer model was made by physical relations in each node, and the indoor moisture generation rate was gained by comparing the model with experimental analyses. From the study, we found out that moisture generation rate was critical and day-periodic, so that we predicted the indoor moisture content by substituting the constant value gained from the average in a day for the moisture generation rate.

Influencing Factors on Forensic Nursing Role Performance of Emergency Department Nurses (응급실 간호사의 법의간호학적 역할 수행에 미치는 영향요인)

  • Kim, Geu-Rin;Sung, Mi Hae
    • Journal of Korean Clinical Nursing Research
    • /
    • v.20 no.1
    • /
    • pp.64-74
    • /
    • 2014
  • Purpose: Purpose of this study was to identify the factors influencing forensic nursing performance role of Emergency Department(ED) nurses. Methods: The study was conducted with 120 ED nurses from Busan. Data were collected during July, 2013 and analyzed using SPSS Win 19.0 program. Results: There were positive correlations between awareness of the forensic nursing role and forensic interest (r=.29, p=.001), between awareness of the forensic nursing role and forensic nursing performance role (r=.54, p<.001), and between forensic experience and forensic nursing performance role (r=.26, p=.004). Awareness of forensic nursing role (${\beta}=.50$, p<.001) and experience in forensics (${\beta}=.24$, p<.001) were significant predictors of forensic nursing role performance and explained 35.9% of the variance. Conclusion: To improve forensic experience, medical institutions should provide education and training for ED nurses to increase their indirect experience. Periodic assessment should also be done. Nurses with training assigned to the ED will enhance the forensic nursing role performance.

Studies on the immunization against field strain after live Newcastle disease virus vaccination (뉴캣슬병 생독백신 접종 후 야외 분리 바이러스에 대한 면역성 조사)

  • 김순태;박인화;김성국;김영환;조광현;손재권
    • Korean Journal of Veterinary Service
    • /
    • v.24 no.2
    • /
    • pp.147-159
    • /
    • 2001
  • This Study was conducted to determine vaccination programs for the control of Newcastle Disease(ND) in chickens and investigate protective effect against Newcastle disease virus (NDV) after live ND vaccination. Maternal HI antibody titer level of chickens according to day(age) 1, 7, 14, 21, 28 and 35 were decreased gradually as 7.10$\pm$0.74, 6.57$\pm$0.74, 3.71$\pm$1.25, 2.20$\pm$1.03, 1.20$\pm$1.23 and 0.50$\pm$0.71. As a result of HI test and ELISA, both chickens vaccinated with VG/GA strain live vaccine at 1-day-old and chickens not vaccinated do not have antibody titer for protection against NDV at 14-day-old. Except for LaSota strain vaccine, in case of vaccination with VG/GA spray and VG/GA, B1 and LaSota strain drinking water at 14-day-old, the protective effect was 100% in chickens inoculated NDV($10^{7.2}$ $EID_{50}$/50${\mu}\ell$, eye drop) at 21-day-old, but not 10~50% at 28-day-old. These data suggest that live NDV vaccination should be given at 10-day-old 20-25day-old for protect against NDV at periodic outbreaks of ND caused by velogenic viscerotropic NDV in the environment of a farm.

  • PDF

The Effects of Compliance and Self Efficacy on Nursing Education Program for Pneumonia Patient (폐렴환자를 위한 간호교육프로그램이 순응도 및 자기효능감에 미치는 효과)

  • Kang, Kyung Sook;Choi, Hanna
    • Journal of Korean Biological Nursing Science
    • /
    • v.22 no.3
    • /
    • pp.184-191
    • /
    • 2020
  • Purpose: The purpose of this study was to validate the effects that the structured pamphlet and education through tablets regarding the daily life management and disease nursing education program has towards pneumonia patients in compliance, and self-efficacy. Methods: This study used the quasi-experimental study design based upon the nonequivalent control group pretest-posttest design. A total of 100 patients-50 patients who were hospitalized February 2020 as the control group and 50 patients who were hospitalized March 2020 as the experimental group - were used as material for the statistical analysis. These data were analyzed with a significance level of p< .05 using the SPSS WIN 21.0 program. Results: The patients' compliance, and self-efficacy had no significance difference between the two previous scores, meaning homogeneity in the two groups. Through verifying the experimental group who had disease and daily-life managing nursing education will have higher scores in compliance (t= 20.95, p< .001), and self-efficacy (t= 17.24, p< .001) than the control group who had not received those education, were statistically significantly different leading to all hypothesis being supported. Conclusion: For improving pneumonia patients' compliance, the methods should be simple, easy to understand, effective in numerous clinical situations, require constant education and reinforcement, and periodic nursing education program.

Analysis of Drug Compliance Status for the Hormone Replacement Therapy (HRT) Treatment Patients (호르몬대체요법 환자의 복약실태분석)

  • Hong, Sun Shik;Lee, Eui Kyoung
    • Korean Journal of Clinical Pharmacy
    • /
    • v.10 no.1
    • /
    • pp.7-12
    • /
    • 2000
  • This study is intended to provide information to menopausal women so they can control their symptoms. The basic data was gathered by interviewed 200 postmenopausal women on a HRT program. The women were questioned about their perception of menopause and compliance to the therapy with the fellowing result $71.7\%$ of the women experianced hot flushes, and $64.1\%$ experienced short term memory loss and some psychological symptoms. The women reported that these symptoms reduced their quality of life. $53\%$ of the women responded that menopause is a natural state and $59.1\%$ agreed to HRT based on their doctor's recommendation. $76.2\%$ of the women reported that HRT was effective, with $74.7\%$ reporting reduced hot flush symptoms $67.3\%$ of the women reported compliance with the medication schedule. and $43.9\%$ reported periodic non-compliance. Although HRT has been shown to be an effective treatment, the study found that less than $10\%$ of postmenopausal women are currently being treated and these treated women are generally negligent in continuing with HRT, The study recommends that a program be developed that explains the benefits and risks of HRT to be distributed to patients being treated by doctors and pharmacists. In conclusions, It is very important for hormone replacement therapy on menopausal women to take more intensive medication consultation to increase medication compliance and effectiveness of pharmacotherapy.

  • PDF

ANALYSIS OF KOREAN HISTORICAL COMET RECORDS (한국의 고대 혜성 기록 분석)

  • Park, So-Yeon;Chae, Jong-Chul
    • Publications of The Korean Astronomical Society
    • /
    • v.22 no.4
    • /
    • pp.151-168
    • /
    • 2007
  • We have analyzed the comet records in the Korean history books: Samguksagi, Goryeosa, and Joseonwangjosillok. For a comparison, the Chinese and Japanese comet records collected by Kronk (1999) have also been analyzed. Power spectrum of the time series of the comet records is used to find periodic comets. Statistically significant periodicities in the power spectrum are detected at the periods of 38-40 years, about 76 years, and 300-400 years for all Korean, Chinese, and Japanese comet records. We have also calculated the past orbits of some comets that have been recently observed, to check whether or not they were recorded in the history books. We use a multistep method to numerically integrate the comet's orbital motion backward in time to 51 B.C. The gravitational force due to the Sun and the nine planets, non-gravitational force, and the relativistic effects have been considered. Comparison of comet's perihelion passage time and the position on the sky with the historical records shows that the comet Halley were recorded at every passage in both Goryeo and Joseon periods. The orbital motion of the comet Pons-Brooks has also been compared with the Korean records. For the comet Tempel-Tuttle, Swift-Tuttle, and Ikeya-Zhang, we have compared our calculation of the orbital motions with those of the previous studies.