• Journal of Korea Port Economic Association
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• v.39 no.2
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• pp.195-204
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• 2023

In this study, the causes of the boom in the container shipping industry pointed out by the media were analyzed. As a result of the analysis, it was found that on the supply side, shipping companies mooring ships in response to IMO environmental regulations caused a rise in freight rates due to 'ships that could not be operated' even if demand increased. In terms of demand, it was determined that the claim that social distancing promoted purchases and increased demand was somewhat unfounded. The reason is that the relationship between social distancing and rising fares is weak.

• Journal of Korean Critical Care Nursing
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• v.16 no.3
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• pp.34-47
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• 2023

Purpose : Exercise may prevent the worsening of chronic kidney disease (CKD) and progression of cardiovascular diseases in patients with CKD. This review aims to identify the best type of exercise modality and summarizes the beneficial effects of exercise on physical and renal function among older adults with pre-dialysis CKD. Methods : A systematic search of PubMed, Embase, CINAHL, Cochrane Library, Web of Science, SCOPUS, and domestic database was performed for randomized controlled trials (RCTs) assessing the effect of exercise intervention on older adults with pre-dialysis CKD published until February 2023. A random-effects meta-analysis was conducted. The risk of bias was assessed using a Cochrane tool for assessing the risk of bias in RCTs (RoB 2.0). Results : The systematic review included 11 RCTs (n = 591, average age 60.2-76), of which 8 could be included for meta-analysis. Exercise was significant in increasing peak oxygen consumption and knee muscle strength among physical functions, and also in improving glomerular filtration rate among kidney functions. Conclusion : Exercise has beneficial effects on physical and renal function among older adults with pre-dialysis CKD. In the future, it is necessary to verify the effectiveness of exercise by subdividing it by type, intensity, duration, and delivery.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.3
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• pp.153-159
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• 2023

As research results showed that ozonated olive oil has excellent therapeutic effects on skin diseases, attempts were made to develop cosmetics manufacturing technology using ozone. Ozone is harmful to the human body, so a separate facility must be prepared to manufacture ozonated olive oil as a cosmetic raw material. The manufacturing device developed in this study was designed as an optimized process for manufacturing cosmetics while ensuring the safety of workers involved in production. To verify the ozonated olive oil produced from the implemented device, a toxicity test was conducted on animals. After applying ozonated oil (high concentration) to the rabbit's back for 24 hours, mortality, general symptoms and symptoms were measured. A skin irritation evaluation was performed. As a result of the experiment, as a result of evaluating the test substance treatment area after a certain period of time, it was confirmed that no skin irritation was observed in all animals, confirming the safety of the ozonated oil production process and the safety of the product.

• Convergence Security Journal
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• v.23 no.5
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• pp.29-34
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• 2023

KMS (Knowledge Management System) is used by various organizations to share information. This KMS includes important information as well as basic information used by each organization. To protect infortant information stored in KMS, many KMS use user identification and authentication features. In such a KMS security environment, if the account information of a user who can access the KMS is leaked, a malicious attacker using the account information can access the KMS and access all authorized important information. In this study, we propose KMS with user access control function that can protect important information even if user account information is leaked. The KMS with the user access control function proposed in this study protects the stored files in the KMS by applying an encryption algorithm. Users can access important documents by using tokens after logging in. A malicious attacker without a Token cannot access important files. As a result of checking the unit function for the target user access control function for effectiveness verification, it was confirmed that the access control function to be provided by KMS is normally provided.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.1
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• pp.11-26
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• 2024

Purpose : This study investigated the empowerment, burnout, and job satisfaction levels among occupational therapists, and to ascertained the effects of empowerment and burnout on job satisfaction. The study aimed to provide foundational data to help increase job satisfaction among occupational therapists. Methods : We surveyed 180 occupational therapists working in the Jeollabuk-do. The survey included 49 questions covering general characteristics, empowerment, burnout, and job satisfaction. Differences in empowerment, burnout, and job satisfaction levels based on general characteristics were analyzed using independent sample t-tests and one-way ANOVA. We performed multiple regression analyses to ascertain the effects of empowerment and burnout on job satisfaction. Results : The average scores for job satisfaction, burnout, and empowerment were 40.32, 58.40, 41.82, respectively. Job satisfaction according to general characteristics showed statistically significant differences based on the annual income and the most difficult treatment. We found that empowerment factors such as perceived importance of the job confidence in one's abilities, and independence and autonomy in job performance, significantly affected job satisfaction. However, the most significant factor influencing job satisfaction was daily fatigue and stress. Conclusion : Job empowerment and burnout of significantly affected job satisfaction among occupational therapists. Occupational therapists have a effect on the daily lives of their clients through interventions, playing a crucial role for each individual client. Thus, increasing the empowerment and job satisfaction levels of occupational therapists and reducing their burnout levels can help improve the quality of life of the clients and enable occupational therapists to provide high-quality services.

• The Journal of the Acoustical Society of Korea
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• v.25 no.4
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• pp.164-171
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• 2006

If the velocities of longitudinal, transverse and leaky surface acoustic waves in an isotropic material are given, the elastic constants and density of the material can be deduced analytically. Those velocities have been measured using three ultrasonic transducers with different vibrational modes so far. In this paper a line-focusing PVDF transducer with divided electrodes was newly proposed and designed for measuring approximate velocities of the three waves. The measurement method established in this study for each waves using the transducer was applied to several isotropic materials including fused quartz. The elastic stiffness constants and densities of the materials were calculated using the measured velocities, and the accuracies were discussed. It was shown that the obtained results are in good accord with the reference values.

• The Journal of the Acoustical Society of Korea
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• v.26 no.8
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• pp.409-414
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• 2007

In spite of many studies of the acoustic field visualization by using sonoluminescence phenomena, the visualization method has not been used widely because it needs high acoustic intensity to get the luminescence intensity enough to observe. Recently, the digital camera with high resolution and big memory makes it possible to get the digital image data even though the brightness of the image is too weak to observe with naked eyes. In this study we investigated the variation of sonoluminescence intensity with the acoustic intensity from an ultrasonic transducer. From this result, the inverse function, which makes the tendency of the variation to linear, was obtained. Using the order of the inverse function, we can expect a matching function. Applying the matching function to digital image data, the distribution of the histogram could be controlled appropriately and the image from relatively weak acoustic intensity could be enhanced by the method.

• The Journal of the Acoustical Society of Korea
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• v.29 no.8
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• pp.476-482
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• 2010

The ultrasonic transient fields and B-mode images of a point target which were simulated for a medical ultrasonic probe with a few defective piezo-elements were compared with those for a normal probe. The present study considered a 3.5 MHz linear array probe whose acoustic beam was formed by the 64 active elements of total 192 elements. The results showed that the maximum amplitude and -3 dB width of the acoustic fields by main-lobes decreased linearly as the defective element number increased from one to four. However, the depths of foci remained almost unchanged, and the pressure differences between main-lobes and side-lobes tended to decrease due to rise in pressures in side-lobes. Such changes in ultrasonic fields affected the B-mode images of point targets. So the artifacts were formed in the right and left side of the target, and the lateral spatial resolutions were decreased while the axial resolution was almost the same.

• The Journal of the Acoustical Society of Korea
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• v.28 no.5
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• pp.416-423
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• 2009

The ultrasonic pressure fields for the 3 MHz linear phased array transducer with sixteen piezoelectric elements of which one may not be operated by defect were simulated theoretically and measured experimentally using a visualization system of the Schlieren method. The simulation results for steering angles of $0^{\circ}$ and $30^{\circ}$ show that the side-lobe patterns of the transducer including a defective element is quite different from the transducer with all normal elements, and those patterns are in good agreement with the results of visualization. It is shown that the defective elements in a linear array transducer can be detected by comparison of the simulated and the visualized side-lobe patterns in two dimensional acoustic fields.

• The Journal of the Acoustical Society of Korea
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• v.28 no.4
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• pp.299-307
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• 2009

In this study, the acoustical properties of micro-speaker had been studied as a function of diaphragm patterns. The diaphragm was divided into two sections, such as edge and dome sides. The pattern change at each side affected the tensile strength of diaphragm. As a result, the resonance frequency was varied with the change. With increasing the number of pattern at the edge side, it was increased at the first, but it reversed to the exponential decrease of that. It increased due to the increase of tensile strength to be caused by using "U" type of drill and whirlwind pattern, and decreasing of drill angle at the edge side. However, it was decreased due to the decrease of tensile strength to be by increasing the number of radiation pattern and dome hight, and decreasing the dome radius at the dome side.