• Title/Summary/Keyword: predictive tool

Search Result 320, Processing Time 0.031 seconds

Finite Element Model for Wear Analysis of Conventional Friction Stir Welding Tool

  • Hyeonggeun Jo;Ilkwang Jang;Yeong Gil Jo;Dae Ha Kim;Yong Hoon Jang
    • Tribology and Lubricants
    • /
    • v.39 no.3
    • /
    • pp.118-122
    • /
    • 2023
  • In our study, we develop a finite element model based on Archard's wear law to predict the cumulative wear and the evolution of the tool profile in friction stir welding (FSW) applications. Our model considers the rotational and translational behaviors of the tool, providing a comprehensive description of the wear process. We validate the accuracy of our model by comparing it against experimental results, examining both the predicted cumulative wear and the resulting changes to the tool profile caused by wear. We perform a detailed comparison between the predictions of the model and experimental data by manipulating non-dimensional coefficients comprising model parameters, such as element sizes and time increments. This comparison facilitates the identification of a specific non-dimensional coefficient condition that best replicates the experimentally observed cumulative wear. We also directly compare the worn tool profiles predicted by the model using this specific non-dimensional coefficient condition with the profiles obtained from wear experiments. Through this process, we identify the model settings that yield a tool wear profile closely aligning with the experimental results. Our research demonstrates that carefully selecting non-dimensional coefficients can significantly enhance the predictive accuracy of finite element models for tool wear in FSW processes. The results from our study hold potential implications for enhancing tool longevity and welding quality in industrial applications.

Usefulness of Korean Version of Behavioral Cue Checklist for Predicting of Patient Violence in Emergency Departments (응급실에서의 폭력 환자 예측을 위한 한국어판 행동신호 사정도구의 유용성 검증)

  • Kim, Jang Mi;Lee, Eun Nam
    • Journal of Korean Academy of Nursing
    • /
    • v.48 no.3
    • /
    • pp.289-297
    • /
    • 2018
  • Purpose: This study aimed to evaluate the usefulness of a behavioral cue checklist (BCC) containing 17 items developed by Wilkes et al. (2010) for identifying potentially violent patients in emergency departments. Methods: This was a prospective observational study to evaluate the usefulness of the Korean version of a BCC (K-BCC) as an assessment tool for predicting patient violence in emergency departments, and was conducted over 4 weeks in a regional emergency medical center located in B City. A total of 1,324 patients were finally analyzed. Results: Logistic regression analysis was performed to investigate whether each item of the K-BCC predicts violence, and a parsimonious set of 8 statistically significant items was selected for the tool. Receiver operating characteristic analysis of the BCC showed that the area under the curve was .97 (95% confidence interval: .94~1.0). The sensitivity, specificity, positive predictive value, and negative predictive value at the cut-off score of 2 were 75.6%, 98.9%, 68.2%, and 99.2%, respectively. Conclusion: The K-BCC was found to be useful in predicting patient violence toward emergency department staff. This tool is simple, and fast to use and can play a significantly role identifying potentially violent patients. Owing to this advance identification, this tool can be helpful in preventing the potential for violence from manifesting as violent behaviors.

Evaluation of a Fall Risk Assessment Tool to Establish Continuous Quality Improvement Process for Inpatients' Falls (낙상예방 활동의 지속적 질 관리 프로세스 확립을 위한 위험 사정도구 평가)

  • Park, Ihn-Sook;Cho, In-Sook;Kim, Eun-Man;Kim, Min-Kyung
    • Journal of Korean Academy of Nursing Administration
    • /
    • v.17 no.4
    • /
    • pp.484-492
    • /
    • 2011
  • Purpose: The aims of study were; (1) to evaluate the validity and sensitivity of a fall-risk assessment tool, and (2) to establish continuous quality improvement (CQI) methods to monitor the effective use of the risk assessment tool. Methods: A retrospective case-control cohort design was used. Analysis was conducted for 90 admissions as cases and 3,716 as controls during the 2006 and 2007 calendar years was conducted. Fallers were identified from the hospital’s Accident Reporting System, and non-fallers were selected by randomized selection. Accuracy estimates, sensitivity analysis and logistic regression were used. Results: At the lower cutoff score of one, sensitivity, specificity, and positive and negative predictive values were 82.2%, 19.3%, 0.03%, and 96.9%, respectively. The area under the ROC was 0.60 implying poor prediction. Logistic regression analysis showed that five out of nine constitutional items; age, history of falls, gait problems, and confusion were significantly associated with falls. Based on these results, we suggested a tailored falls CQI process with specific indexes. Conclusion: The fall-risk assessment tool was found to need considerable reviews for its validity and usage problems in practice. It is also necessary to develop protocols for use and identify strategies that reflect changes in patient conditions during hospital stay.

Evaluation of BreastLight as a Tool for Early Detection of Breast Lesions among Females Attending National Cancer Institute, Cairo University

  • Labib, Nargis Albert;Ghobashi, Maha Mohamed;Moneer, Manar Mohamed;Helal, Maha Hesien;Abdalgaleel, Shaimaa Abdalaleem
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.14 no.8
    • /
    • pp.4647-4650
    • /
    • 2013
  • Background: Breast illumination was suggested as a simple method for breast cancer screening. BreastLight is a simple apparatus for this purpose. Objective: To evaluate the diagnostic performance of BreastLight as a screening tool of breast cancer in comparison to mammography and histopathology. Materials and Methods: This hospital-based cross sectional study was conducted in the mammography unit of the radiodiagnosis department at National Cancer Institute, Cairo University. All participants were subjected to breast examination with the BreastLight tool, mammography and ultrasonography. Suspicious cases were biopsied for histopathological examination which is considered as a gold standard. Results: The mean age of the participants was $46.3{\pm}12.4$ years. Breast illumination method had sensitivity, specificity, positive predictive value, negative predictive value and total accuracy of 93.0%, 73.7%, 91.4%, 77.8% and 88.2%, respectively in detection of breast cancer. Conclusions: Breast illumination method with BreastLight apparatus is a promising easy-to-use tool to screen for breast cancer suitable for primary health care physician or at-home use. It needs further evaluation especially in asymptomatic women.

Study on Analysis Process for Slip Torque Design Control of Impact Hammer Drills (임팩트햄머 드릴의 슬립토크 설계 제어를 위한 분석 프로세스 고찰)

  • Kim, Seung Hyeon;Kwon, Sang Youp;Ko, Dong Shin;Hur, Deog Jae;Dong, Kwang Ho
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.33 no.5
    • /
    • pp.401-407
    • /
    • 2016
  • This paper describes the derivation methodology of the working torque predictive model that can be used in the initial design stages of the impact hammer tool. The working torque control mechanism is designed, taking into account various factors, such as the force of the spring and friction. Firstly, the analysis dynamic model for working environments was modeled as an additional bush and spring, and verified by comparing the test results of the working torque. Secondly, the main performance parameters of the working torque were theoretically defined by analyzing the operating mechanism. The equation to predict the working torque was derived using the dynamic analysis results according to the value changes of the parameters. The prediction equation of the working torque was validated by comparing the predicted results with the experimental data. The error difference between the experimental data and the predictive model results was found to be 8.62%.

Receiver operating characteristic curve analysis of the timed up and go test as a predictive tool for fall risk in persons with stroke: a retrospective study

  • Lim, Seung-yeop;Lee, Byung-jun;Lee, Wan-hee
    • Physical Therapy Rehabilitation Science
    • /
    • v.7 no.2
    • /
    • pp.54-60
    • /
    • 2018
  • Objective: Persons with chronic stroke fall more often than healthy elderly individuals. The Timed Up and Go test (TUG) is used as a fall prediction tool, but only provides a result for the total measurement time. This study aimed to determine the optimal cut-off values for each of the 6 components of the TUG. Design: Retrospective study. Methods: Thirty persons with chronic stroke participated in the study. TUG evaluation was performed using a wearable miniaturized inertial sensor. Sensitivity, specificity, and predictive values were calculated using the Receiver Operating Characteristic (ROC) curve analysis for the measured values in each section. Optimal values for fall risk classification were determined. Logistic regression analysis was used to investigate the risk of future falls based on TUG. Results: The cut-off values of the 6 sections of the TUG were determined, as follows: sit-to-stand >2.00 seconds (p<0.05), forward gait >4.68 seconds (p<0.05), mid-turn >3.82 seconds (p<0.05), return gait >4.81 seconds (p<0.05), end-turn >2.95 seconds (p<0.05), and stand-to-sit >2.13 seconds (p<0.05). The risk of falling increased by 2.278 times when the mid-turn value was >3.82 seconds (p<0.05). Conclusions: The risk of falls increased by 2.28 times when the value of the mid-turn interval exceeded 3.82 seconds. Therefore, when interpreting TUG results, the predictive accuracy for falls will be higher when the measurement time for each section is analyzed, together with the total time for TUG.

Significance of Ultrasonography in Diagnosis of Medial Meniscus Tear (내측 반월상 연골 파열의 진단에서 초음파의 의의)

  • Kim, Jung-Man;Im, Dong-Sun;Kim, Tae-Hyung;Kim, Jong-Ick;Lee, Kyu-Jo
    • The Journal of Korean Orthopaedic Ultrasound Society
    • /
    • v.4 no.1
    • /
    • pp.1-6
    • /
    • 2011
  • Purpose: To evaluate the usefulness of ultrasonography in diagnosis of the medial meniscus tear as a screening tool before performing magnetic resonance imaging. Materials and Methods: From April 2009 to September 2010, magnetic resonance imaging (MRI) was taken in 147 knees out of 341 knees examined with ultrasonography (US) under the suspicion of medial meniscus tear. The sonographic findings were 16 without abnormality, 12 inhomogeneity, 4 cluster, 60 cleavage and 55 more than 5mm medial extrusion of medial meniscus. In Statistical analysis, sensitivity and specificity, positive predictive value and negative predictive values were calculated. Results: The MRI showed abnormality in 104 knees. Sensitivity and specificity of ultrasonography for MRI was 94.2% and 23.3%, respectively. Positive predictive value was 74.8%, negative predictive value was 62.5%. The positive predictive value of ultrasonography were 58.3% in heterogeneity, 100% in showing cluster, 75% in visible cleft and 80% in medial extrusion. Conclusion: The US is a useful tool in prediction of medial meniscus tear before confirming it in high-cost MRI.

  • PDF

Predictive Factors of Health promotion behaviors of Industrial Shift Workers (산업장 교대근무 근로자의 건강증진행위 예측요인)

  • Kim, Young-Mi
    • Korean Journal of Occupational Health Nursing
    • /
    • v.11 no.1
    • /
    • pp.13-30
    • /
    • 2002
  • Industrial shift workers feels suffer mental stresses which are caused by unfamiliar day sleep, noisy environment, sleeping disorder by bright light, unusual contacts with family, difficulty in meeting with friends or having formal social meetings and other social limitations such as the use of transportation. Such stresses influence health of the workers negatively. Thus the health promotion policy for shift workers should be made considering the workers' ways of living and shift work specially. This study attempted to provide basic information for development of the health promotion program for industrial shift workers by examining predictive factors influencing health promotion behaviors of those workers. In designing the study, three power generation plants located in Pusan and south Kyungsang province were randomly selected and therefrom 280 workers at central control, boiler and turbine rooms and environmental chemistry parts whose processes require shift works were sampled as subjects of the study. Data were collected two times from September 17 to October 8, 1999 using questionnaires with helps of safety and health managers of the plants. The questionnaires were distributed through mails or direct visits. Means for the study included the measurement tool of health promotion behavior provided by Park(1995), the tool of self-efficacy measurement by Suh(1995), the tool of internal locus of control measurement by Oh(1987), the measurement tool of perceived health state by Park(1995) and the tool of social support measurement by Paek(1995). The collected data were analyzed using SPSS program. Controlling factors of the subjects were evaluated in terms of frequency and percentage ratio Perceived factors and health promotion behaviors of the subjects were done so in terms of mean and standard deviation, and average mark and standard deviation, respectively. Relations between controlling and perceived factors were analyzed using t-test and ANOVA and those between perceived factors and the performance of health promotion behaviors, using Pearson's Correlation Coefficient. The performance of health promotion behaviors was tested using t-test, ANOVA and post multi-comparison (Scheffe test). Predictive factors of health promotion behavior were examined through the Stepwise Multiple Regression Analysis. Results of the study are summarized as follows. 1. The performance of health promotion behaviors by the subjects was evaluated as having the value of mean, $161.27{\pm}26.73$ points(min.:60, max.:240) and average mark, $2.68{\pm}0.44$ points(min.:1, max.:4). When the performance was analyzed according to related aspects, it showed the highest level in harmonious relation with average mark, $3.15{\pm}.56$ points, followed by hygienic life($3.03{\pm}.55$), self-realization ($2.84{\pm}.55$), emotional support($2.73{\pm}.61$), regular meals($2.71{\pm}.76$), self-control($2.62{\pm}.63$), health diet($2.62{\pm}.56$), rest and sleep($2.60{\pm}.59$), exercise and activity($2.53{\pm}.57$), diet control($2.52{\pm}.56$) and special health management($2.06{\pm}.65$). 2. In relations between perceived factors of the subjects(self-efficacy, internal locus of control, perceived health state) and the performance of health promotion behaviors, the performance was found having significantly pure relations with self-efficacy (r=.524, P=.000), internal locus of control (r=.225, P=.000) and perceived health state(r=.244, P=.000). The higher each evaluated point of the three factors was, the higher the performance was in level. 3. When relations between the controlling factors(demography-based social, health-related, job-related and human relations characteristics) and the performance of health promotion behaviors were analyzed, the performance showed significant differences according to marital status (t=2.09, P= .03), religion(F=3.93, P= .00) and participation in religious activities (F=8.10, P= .00) out of demography-based characteristics, medical examination results (F=7.20, P= .00) and methods of the collection of health knowledge and information(F=3.41, P= .01) and methods of desired health education(F=3.41, P= .01) out of health-related characteristics, detrimental factors perception(F=4.49, P= .01) and job satisfaction(F=8.41, P= .00) out of job-related characteristics and social support(F=14.69, P= .00) out of human relations characteristics. 4. The factor which is a variable predicting best the performance of health promotion behaviors by the subjects was the self-efficacy accounting for 27.4% of the prediction, followed by participation in religious activities, social support, job satisfaction, received health state and internal locus of control in order all of which totally account for 41.0%. In conclusion, the predictive factor which most influence the performance of health promotion behaviors by shift workers was self-efficacy. To promote the sense, therefore, it is necessary to develop the nursing intervention program considering predictive factors as variables identified in this study. Further industrial nurses should play their roles actively to help shift workers increase their capability of self-management of health.

  • PDF

Validation on Adult Fall Assessment Tools: Focusing on Hospitalized Patients in a General Hospital (낙상위험 사정도구의 타당도 비교: 일개 종합병원의 입원 환자를 중심으로)

  • Kim, Hayng Suk;Choi, Eun Hee
    • Journal of muscle and joint health
    • /
    • v.31 no.2
    • /
    • pp.65-74
    • /
    • 2024
  • Purpose: This study was conducted to verify fall predictive power and reasonable fall risk assessment tool by a comparative analysis of the sensitivity, specificity, positive forecast and negative forecast of each tool by applying Morse Fall Scale (MFS), Johns Hopkins Fall Risk Assessment Tool (JHFRAT), and Fall Assessment Scale-Korean version (FAS-K) through electronic medical records to adult patients hospitalized in a general hospital in Korea. Methods: We performed a retrospective evaluation study from January to December 2018, 123 fall groups experiencing falls during hospitalization and 123 non-falls groups were selected. Data presented a reasonable assessment tool that predicts and distinguishes fall high-risk patients through area comparison based on the ROC curve for each tool. Results: In the ROC curve analysis by fall risk assessment group, the AUC of MFS is shown to be .706 (good), JHFRAT is shown to be .649 (sufficient) and FAS-K is shown to be .804 (very good). FAS-K at a cut-off score of 4, sensitivity, specificity, and positive and negative prediction values were 83.7%, 60.2%, 67.8%, and 78.7%, respectively. Conclusion: Based on the above findings, it is believed that the FAS-K was presented as a suitable and reasonable tool for predicting falls for adult patients in general hospitals.

A Study on the cutting forces prediction using machining theory in end milling (절삭이론을 이용한 엔드밀 가공에서의 절삭력 예측에 관한 연구)

  • Jung, Sung-Chan;Kim, Kug-Weon
    • Proceedings of the KSME Conference
    • /
    • 2004.11a
    • /
    • pp.928-933
    • /
    • 2004
  • A new approach for modelling and simulation of the cutting forces in end milling processes is presented. In this approach, the cutting forces in end milling are modelled based on a predictive machining theory, in which the machining characteristic factors are predicted from input data of fundamental workpiece material properties, tool geometry and cutting conditions. In the model, each tooth of a end milling cutter is divided into a number of slices along the cutter axis. The cutting action of each of the slices is modelled as an oblique cutting process. For the first slice of each tooth, it is modelled as oblique cutting with end cutting edge effect, whereas the cutting actions of other slices are modelled as oblique cutting without end cutting edge effect. The cutting forces in the oblique cutting processes are predicted using a predictive machining theory. The total cutting forces acting on the cutter is obtained as the sum of the forces at all the cutting slices of all the teeth. A Windows-based simulation system for the cutting forces in end milling is developed using the model. Experimental milling tests have been conducted to verify the simulation system.

  • PDF