• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.698-704
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• 2022

In this paper, the radiated aerodynamic noise generated from sound sources of a nozzle inflow is quantitatively investigated and compared with experimental results of externally radiated noise. A high-resolution unsteady compressible Large Eddy Simulation (LES) technique is used to accurately predict the internal and external flow of three types of nozzle shape. Through using the vortex sound source for sound sources, the geometry of nozzle neck is identified as most significant aerodynamic noise sources. For validation of quantitative analysis, the vortex sound source intensity of internal nozzle flow is compared with results of external radiated noise of calculation and experiment.

• Korean System Dynamics Review
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• v.10 no.1
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• pp.77-95
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• 2009

The ever-increasing government budget constraints have led to a continued decline in the increase rate for defense spending, and the government's 5-year National Fiscal Management Plan has served to reinforce the verification and validation procedures for the Force Improvement Programs (FIP) budget requirements and performance. Additionally, as large programs are controlled in accordance with the Total Program Cost Management Guidelines, timely and credible feasibility study and performance measurement need to be conducted. Due to these internal and external circumstances, needs have surged for feasibility and economic effectiveness study for big ticket projects in the FIP sector, with an increasing number of studies conducted by external research institutes. However, questions have been raised regarding the credibility and thoroughness of the program analyses performed by these research institutes due to various restrictions. This paper analyzes and identifies the structural limitations and problems using a systems thinking approach, and examines the systemic characteristics of the program analysis system. It also presents policy intervention recommendations based on the theory of systems thinking, a method to regularize and reinforce the program analysis system. Policy interventions recommended to ensure alignment of the external studies to the clear analysis objectives and resolve the bottlenecks in the external analysis include training those in charge of external study commissioning for a short term intervention, and increasing the number of research institutes and consulting agencies utilizing analysis and evaluation experts who transition to the private sector from the military for a long term intervention. additionally presented are strategies and policy alternatives to best utilize these policy interventions. They will contribute to the stable funding of Force Improvement Programs and efficient utilization of defense budget.

• Radiation Oncology Journal
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• v.36 no.2
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• pp.139-146
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• 2018

Purpose: IBTR! 2.0 nomogram is web-based nomogram that predicts ipsilateral breast tumor recurrence (IBTR). We aimed to validate the IBTR! 2.0 using an external data set. Materials and Methods: The cohort consisted of 2,206 patients, who received breast conserving surgery and radiation therapy from 1992 to 2012 at our institution, where wide surgical excision is been routinely performed. Discrimination and calibration were used for assessing model performance. Patients with predicted 10-year IBTR risk based on an IBTR! 2.0 nomogram score of <3%, 3%-5%, 5%-10%, and >10% were assigned to groups 1, 2, 3, and 4, respectively. We also plotted calibration values to observe the actual IBTR rate against the nomogram-derived 10-year IBTR probabilities. Results: The median follow-up period was 73 months (range, 6 to 277 months). The area under the receiver operating characteristic curve was 0.607, showing poor accordance between the estimated and observed recurrence rate. Calibration plot confirmed that the IBTR! 2.0 nomogram predicted the 10-year IBTR risk higher than the observed IBTR rates in all groups. High discrepancies between nomogram IBTR predictions and observed IBTR rates were observed in overall risk groups. Compared with the original development dataset, our patients had fewer high grade tumors, less margin positivity, and less lymphovascular invasion, and more use of modern systemic therapies. Conclusions: IBTR! 2.0 nomogram seems to have the moderate discriminative ability with a tendency to over-estimating risk rate. Continued efforts are needed to ensure external applicability of published nomograms by validating the program using an external patient population.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.5
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• pp.87-98
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• 2020

At the point of implementing policies related to urban heat through the overall environmental assessment of the city using national data, citizen science projects that can collect data in a wide range are emerging for effective policy establishment. Although the utility of citizen data is improving, data quality is a primary concern for researchers employing public participation in scientific research. In this study, validation was conducted based on citizen data acquired in the "Suwon City Heat Map Project", and the applicability to temperature monitoring was confirmed based on the results. As a result of analyzing the validity verification of citizen data using three methods, the data result value is 0.843, RMSE: 0.683℃, and a meaningful value was found within 3km of national data. We found that citizen data utilization is high through the results of this study and These projects are expected to be used as basic data for establishing effective policies or can be reflected in the various planning.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10683-10690
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• 2015

The big gap between efficacy of population level prevention and expectations due to heterogeneity and complexity of cancer etiologic factors calls for selective yet personalized interventions based on effective risk assessment. This paper documents our research protocol aimed at refining and validating a two-stage and web-based cancer risk assessment tool, from a tentative one in use by an ongoing project, capable of identifying individuals at elevated risk for one or more types of the 80% leading cancers in rural China with adequate sensitivity and specificity and featuring low cost, easy application and cultural and technical sensitivity for farmers and village doctors. The protocol adopted a modified population-based case control design using 72, 000 non-patients as controls, 2, 200 cancer patients as cases, and another 600 patients as cases for external validation. Factors taken into account comprised 8 domains including diet and nutrition, risk behaviors, family history, precancerous diseases, related medical procedures, exposure to environment hazards, mood and feelings, physical activities and anthropologic and biologic factors. Modeling stresses explored various methodologies like empirical analysis, logistic regression, neuro-network analysis, decision theory and both internal and external validation using concordance statistics, predictive values, etc..

• 한국체육학회지인문사회과학편
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• v.54 no.5
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• pp.207-219
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• 2015

The purpose of this study was to test the validation of the Korean version of the Talent Development Environment Questionnaire for sport(TDEQ; Martindale et al., 2010), developed through the conceptual and statistical verification stages(substantive stage-structural stage-external stage). In accordance with the procedure of translation, the substantive concepts of the items were reviewed. The data were collected from a sample of 244 ; 117 high school student-athletes and 127 university student-athletes. In order to test the internal structure of TDEQ, EFA/CFA, and internal consistency were performed. As a result, Korean version of the TDEQ had 5 factors with 38 items. External relationship by correlation analysis and group differentiation analysis were obtained to enhance the validity of the test. Overall, the Korean TDEQ will be used as a diagnostic and evaluation tool at the stage of detection, identification, selection, and development of Sport Talent.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2852-2859
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• 2020

This paper deals with the simulation-based design optimization and experimental validation of the characteristics of an in-core silver Self-Powered Neutron Detector (SPND). Optimized dimensions of the SPND are determined by combining Monte Carlo simulations and analytical methods. As a first step, the Monte Carlo transport code MCNPX is used to follow the trajectory and fate of the neutrons emitted from an external source. This simulation is able to seamlessly integrate various phenomena, including neutron slowing-down and shielding effects. Then, the expected number of beta particles and their energy spectrum following a neutron capture reaction in the silver emitter are fetched from the TENDEL database using the JANIS software interface and integrated with the data from the first step to yield the origin and spectrum of the source electrons. Eventually, the MCNPX transport code is used for the Monte Carlo calculation of the ballistic current of beta particles in the various regions of the SPND. Then, the output current and the maximum insulator thickness to avoid breakdown are determined. The optimum design of the SPND is then manufactured and experimental tests are conducted. The calculated design parameters of this detector have been found in good agreement with the obtained experimental results.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.487-495
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• 1998

In this paper, a new type of implantable middle ear hearing aid, which consists of external loop coil, a small magnet and a simple external device, is proposed. The internal device of proposed type consists of only a small magnet and the external device does not need to be positioned behind the ear or in the ear canal. The proposed type is excellent in cosmetic sides and very convenient to use, because the external device can be hidden in upper garment and collar of clothes. Also, purposely this type doesn't need to be small on the size of battery, which means it has longer battery life. Therefore, the battery is not necessary to be charged frequently. It also can solve the difficulty of gap calibration at surgical operation which conventional Implantable middle. Therefore, the battery is not necessary to be charged frequently. It also can solve the difficulty of gap calibration at surgical operation which conventional implantable middle ear hearing aid has. We investigate the performance of proposed implantable middle ear bearing aid and we analyze that proposed type is appropriate for mild and severe hearing impaired person and the result of experiment showed the accuracy of our analysis. For the validation of our analysis we used the temporal bone at the experiment and confirm that ossicles can be vibrated when the proposed system In startled in the body.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.43-49
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• 2011

In this study, the dynamic characteristics of an air spring connected with an external chamber through a flexible tube are examined. The uncoupled dynamic parameters of the air spring are identified through experiments, followed by the suggestion of a model-based approach to obtain the remaining coupled dynamic parameters using the various frequency response functions derived in PART I paper [1]. To improve or control the damping characteristics of the air spring, this vibration isolation air spring system is physically established in laboratory scale. And we attempt to identify various parameters used to describe to air spring system by both theoretically [1] and experimentally, which is performed in this report. The damping parameter of the tube system is identified through experiments on the system incorporated with the air cylinder, and a nonlinear regression procedure is employed to find solutions. The resulting value is used to expect the frequency response function of dynamic pressure in the top chamber (air spring) with respect to that in the bottom chamber (external chamber). Comparison with the experimental data supports the validity of the present estimation procedures. Also, the dynamic mechanism of the damping effects particularly in a low frequency range is investigated through this experimental endeavor.

• Journal of Radiation Protection and Research
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• v.47 no.2
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• pp.77-85
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• 2022

Background: After the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, a model was developed to estimate the external exposure doses for residents who were expected to return to their homes after evacuation orders were lifted. However, the model's accuracy and uncertainties in parameters used to estimate external doses have not been evaluated. Materials and Methods: The model estimates effective doses based on the integrated ambient dose equivalent (H^*(10)) and life patterns, considering a dose reduction factor to estimate the indoor H^*(10) and a conversion factor from H^*(10) to the effective dose. Because personal dose equivalent (H_p(10)) has been reported to agree well with the effective dose after the FDNPS accident, this study validates the model's accuracy by comparing the estimated effective doses with H_p(10). The H_p(10) and life pattern data were collected for 36 adult participants who lived or worked near the FDNPS in 2019. Results and Discussion: The estimated effective doses correlated significantly with H_p(10); however, the estimated effective doses were lower than H_p(10) for indoor sites. A comparison with the measured indoor H^*(10) showed that the estimated indoor H^*(10) was not underestimated. However, the H_p(10) to H^*(10) ratio indoors, which corresponds to the practical conversion factor from H^*(10) to the effective dose, was significantly larger than the same ratio outdoors, meaning that the conversion factor of 0.6 is not appropriate for indoors due to the changes in irradiation geometry and gamma spectra. This could have led to a lower effective dose than H_p(10). Conclusion: The estimated effective doses correlated significantly with H_p(10), demonstrating the model's applicability for effective dose estimation. However, the lower value of the effective dose indoors could be because the conversion factor did not reflect the actual environment.