• Journal of Advanced Navigation Technology
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• v.25 no.6
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• pp.485-492
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• 2021

Vision-based autonomous precision landing technology for UAVs requires precise position estimation and landing guidance technology. Also, for safe landing, it must be designed to determine the safety of the landing point against ground obstacles and to guide the landing only when the safety is ensured. In this paper, we proposes vision-based navigation, and algorithms for determining the safety of landing point to perform autonomous precision landings. To perform vision-based navigation, CNN technology is used to detect landing pad and the detection information is used to derive an integrated navigation solution. In addition, design and apply Kalman filters to improve position estimation performance. In order to determine the safety of the landing point, we perform the obstacle detection and position estimation in the same manner, and estimate the speed of the obstacle using LSM. The collision or not with the obstacle is determined based on the CPA calculated by using the estimated state of the obstacle. Finally, we perform flight test to verify the proposed algorithm.

• Anxiety and mood
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• v.19 no.2
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• pp.83-93
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• 2023

Objective : This study aimed to develop a customized EAP program for post office workder, incorporating mindfulness and positive psychology, and to test the effectiveness of the intervention on job burnout and well-being of the postal workers. Methods : Participants were currently working postal employees and were recruited voluntarily through the website of the Korea post human resources development institute. A total of 42 workers participated in the program until the end and completed preprogram and post program questionnaires. Results : The results showed that the mindfulness-positive psychology EAP program significantly improved the participants' mindfulness (t=-5.021, p<0.001), job burnout (t=5.824, p<0.001), self-esteem (t=-4.852, p<0.001), positive affect (t=-4.534, p<0.001), negative affect (t=5.635, p<0.001), and body tension (t=6.355, p<0.001), with statistically significant effects on all measures. Conclusion : The results indicated that the mindfulness-positive psychology EAP class had a significantly positive effect on increasing mindfulness, self-esteem, and positive affect and decreasing job burnout, negative affect, and body tension among postal workers, demonstrating the usefulness of an integrated approach.

• Journal of Korean Academy of Nursing
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• v.53 no.6
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• pp.652-665
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• 2023

Purpose: This study aimed to develop a nursing clinical judgment scale (NCJS) and verify its validity and reliability in assessing the clinical judgment of nurses. Methods: A preliminary instrument of the NCJS comprising 38 items was first developed from attributes and indicators derived from a literature review and an in-depth/focus interview with 12 clinical nurses. The preliminary tool was finalized after 7 experts conducted a content validity test based on a data from a preliminary survey of 30 hospital nurses in Korea. Data were collected from 443 ward, intensive care unit, emergency room nurses who voluntarily participated in the survey through offline and online for the verification of the construct validity and reliability of the scale. Results: The final scale comprised 23 items scored on a 5-point Likert scale. Six factors - integrated data analysis, evaluation and reflection on interventions, evidence on interventions, collaboration among health professionals, patient-centered nursing, and collaboration among nurse colleagues - accounted for 64.9% of the total variance. Confirmatory factor analysis supported the fit of the measurement model, comprising six factors (root mean square error of approximation = .07, standardized root mean square residual = .04, comparative fit index = .90). Cronbach's α for all the items was .92. Conclusion: The NCJS is a valid and reliable tool that fully reflects the characteristics of clinical practice, and it can be used effectively to evaluate the clinical judgment of Korean nurses. Future research should reflect the variables influencing clinical judgment and develop an action plan to improve it.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.3
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• pp.675-684
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• 2024

The purpose of the study is to determine the relationship between the infection control organizational culture, infection prevention environment, and infection control performance of nurses at a children's hospital and to identify factors affecting infection control performance. The subjects of the study were 160 nurses from five children's hospitals, and data collection was conducted from February 19 to 29, 2024. Data analysis was performed using frequency, percentage, mean, standard deviation, and difference analysis of variables using t-test, ANOVA, Pearson's correlation analysis, and multiple regression analysis. As a result of the study, infection control performance was positively correlated with infection control organizational culture (r= .610, p< .001) and infection prevention environment (r= .586, p< .001), and as a result of multiple regression analysis, infection control organization The influencing factors appeared in the following order: culture (β= .369), infection prevention environment (β= .312), medical institution accreditation evaluation experience (β= .165), and infection control education experience (β= .137), and the overall explanatory power was It was 50.8% (F=41.966, p< .001). Based on the results of this study, to carry out infection control in children's hospitals, integrated management including the will and effort of individual nurses, support and policy from medical institutions and the government is needed, and the development of an infection control education program that takes into account the special characteristics of children's hospital nurses. Application is necessary.

• Journal of Aerospace System Engineering
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• v.18 no.2
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• pp.12-20
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• 2024

The application of reinforcement design to ensure the structural safety of electronics in small satellites is limited by the spatial constraints of the satellite structure during launch vibrations. Additionally, a reliable evaluation approach is needed for mounting highly integrated devices that are susceptible to fatigue failure. Although the Steinberg fatigue failure theory has been used to assess the structural integrity of electronic devices, recent studies have highlighted its theoretical limitations. In this paper, we propose a structural methodology based on the critical strain theory to design the digital control unit (DCU) of the X-band SAR payload component for the small SAR technology experimental project (S-STEP), a small satellite constellation. To validate the design, we conducted modal and random analyses using simplified modeling techniques. Based on our methodology, we ultimately demonstrated the structural safety of the electronics through analysis results, safety margin derivation, and functional tests conducted both before and after the launch test.

• The Journal of the Acoustical Society of Korea
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• v.28 no.7
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• pp.680-685
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• 2009

In this paper, we propose a efficient noise power estimation technique for an integrated acoustic echo and noise suppression system in a frequency domain. The proposed method uses speech absence probability (SAP) derived from the microphone input signal as the smoothing parameter updating noise power to reduce the noise power estimation error resulted from the distortions in the unified structure where the noise suppression (NS) operation is placed after the acoustic echo suppression (AES) algorithm. Therefore, in the proposed approach, the smoothing parameter based on SAP derived from the input signal instead of echo-suppressed signal should stop updating noise power estimates during the distorted noise spectrum periods. The performance of the proposed algorithm is evaluated by the objective test under various environments and yields better results compared with the conventional scheme.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.617-628
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• 2023

This study aimed to evaluate the engine load factor (LF) of a 90 kW agricultural combine harvester. The combine harvester used in this study is equipped with an electronic engine, and real-time engine data (torque and speed) was collected through a controller area network. The speed of the combine harvester during harvesting operation was divided into three levels (4, 5, and 6 km/h) for the representative operation speed range of 4 to 6 km/h. The LF was calculated using the engine load data measured in real time during harvesting. A weight was applied to the LF for each condition based on a survey of the usage. Results of the field test showed that the LF was 0.53, 0.64, and 0.87 at working speeds of 4, 5, and 6 km/h, respectively. The highest engine load factor was recorded at 6 km/h. Finally, based on the weight for the usage applied, the integrated engine LF was analyzed to be 0.69, which is approximately 144% higher than the currently applied LF of 0.48. A study on LF analysis for the entire work cycle, including idling and driving of the combine harvester, will be addressed in a future study.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.129-135
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• 2024

In this paper, an analytical approach for the design and analysis of an aperiodic electromagnetic bandgap (EBG)-based power distribution network (PDN) in high-speed integrated-circuit (IC) packages and printed circuit boards (PCBs) is proposed. Aperiodic EBG is an effective method to solve the noise problem of high-speed IC packages and PCBs. However, its analysis becomes challenging due to increased computation time. To overcome the problem, the proposed analytical method entails deriving impedance parameters for EBG island and the overall PDN, which includes locally placed EBG structures. To validate the proposed method, a test vehicle is fabricated, demonstrating good agreement with the measurements. Significantly, the proposed analytical method reduces computation time by 99.7 %compared to the full-wave simulation method.

• Journal of Korean Society for Quality Management
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• v.52 no.1
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• pp.43-56
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• 2024

Purpose: The injection molding process, crucial for plastic shaping, encounters difficulties in sustaining product quality when replacing injection machines. Variations in machine types and outputs between different production lines or factories increase the risk of quality deterioration. In response, the study aims to develop a system that optimally adjusts conditions during the replacement of injection machines linked to molds. Methods: Utilizing a dataset of 12 injection process variables and 52 corresponding sensor variables, a predictive model is crafted using Decision Tree, Random Forest, and XGBoost. Model evaluation is conducted using an 80% training data and a 20% test data split. The dependent variable, classified into five characteristics based on temperature and pressure, guides the prediction model. Bayesian optimization, integrated into the selected model, determines optimal values for process variables during the replacement of injection machines. The iterative convergence of sensor prediction values to the optimum range is visually confirmed, aligning them with the target range. Experimental results validate the proposed approach. Results: Post-experiment analysis indicates the superiority of the XGBoost model across all five characteristics, achieving a combined high performance of 0.81 and a Mean Absolute Error (MAE) of 0.77. The study introduces a method for optimizing initial conditions in the injection process during machine replacement, utilizing Bayesian optimization. This streamlined approach reduces both time and costs, thereby enhancing process efficiency. Conclusion: This research contributes practical insights to the optimization literature, offering valuable guidance for industries seeking streamlined and cost-effective methods for machine replacement in injection molding.

• Physical Therapy Rehabilitation Science
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• v.13 no.1
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• pp.86-94
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• 2024

Objective: To evaluate the changes in bladder capacity and storage through non-invasive neuromodulation by application of repetitive Trans magnetic stimulation (rTMS) and genital nerve stimulation (GNS) in traumatic spinal cord survivors. Design: A Single Case Study. Method: The Patient was registered in trail with the clinical trial registry of India (CTRI/2022/05/042431). The Patient was interposed with rTMS on lumbar area, from T11-L4 vertebrae with 1 Hz and the intensity was 20% below that elicited local paraspinal muscular contraction for 13 minutes. GNS was placed over dorsum of the penis with the cathode at the base and anode 2 cm distally at 20 Hz, 200 microseconds, Continuous and biphasic current was delivered and amplitude of stimulation necessary to elicit the genito-anal reflex. For assessment, Neurological examination was done for peri-anal sensation (PAS), voluntary anal contraction (VAC) and bulbocavernous reflex (BCR), deep anal pressure (DAP), and American Spinal Injury Association Impairment Scale (ASIA scale). Outcome assessment was done using Urodynamics, Spinal Cord Independence Measure Scale Version-III (SCIM-III), American Spinal Injury Association Impairment Score (ASIA Score), Beck's Depression Inventory Scale (BDI). The baseline evaluation was taken on Day 0 and on Day 30. Results: The pre-and post-data were collected through ASIA score, SCIM-III, BDI and Urodynamics test which showed significant improvement in bladder capacity and storage outcomes in the urodynamics study across the span of 4 weeks. Conclusion: rTMS along with GNS showed improvement in bladder capacity & storage, on sensory-motor score, in functional independence of individual after SCI.