• Journal of the Korean Society for Heat Treatment
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• v.36 no.3
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• pp.161-173
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• 2023

This study investigated the effects of K_N and process time on the formation of a compound layer at a nitriding temperature of 540℃ for SCR420H material. As a result of controlled nitriding from 3 h to 20 h at K_N 1.2 atm^-1/2, compound layers were formed up to about 10 ㎛, and an effective hardening depth of about 460 ㎛ was obtained. Initially, an ε+γ' complex phase was formed, and the phase fraction changed over time, and finally, the fraction of ε phase decreased to less than 1%. With higher K_N, the compound thickness increased, a pore layer was formed on the surface, and the surface hardness decreased. By applying the controlled nitriding process, it was possible to produce annulus gears with a compound thickness of 12.8 ㎛ and an ε phase of 5% or less. The annulus gears made through controlled nitriding were mounted on a 6-speed transmission and tested for durability. As a result, the durability test of 250,000 km was satisfied, and the transmission efficiency was also confirmed to be expected.

• Journal of Digital Convergence
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• v.20 no.1
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• pp.343-347
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• 2022

This research tested the relationship between professionalism perception and organizational commitment of social workers in welfare centers for disabled persons. And this analyzed the the mediating effect of job satisfaction. We surveyed 239 social workers in 14 centers of C Province and D City. The analysis result is that social workers' professionalism perception influenced the organizational commitment and the job satisfaction mediated between the variables. According to this study result, we can suggest some plans to improve social workers' organizational commitment. For improving social workers' professionalism perception, it is important to carry out strengthening of professional remuneration education, recruitment scores for calling as a professional, and reasonable operation reflecting their opinions. To promote social workers' job satisfaction, we need to actively provide counseling to social workers who experience emotional labor, to offer appropriate supervision and job training, and to develop and disseminate programs to improve the leadership of the facility's chiefs.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.375-386
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• 2022

As information asset protection is recognized as an important management factor for organizations, organizations are increasing their investments in information security(IS) policies and technologies. However, strict application of IS may cause non-compliance behavior through IS stress on employees of the organization. Accordingly, this study suggests a mechanism by which employee stress affects IS compliance intentions through self-determination, and a method to reinforce IS compliance intentions through person-organization fit. We conducted an online survey of employees working at companies that adopted IS policies and tested hypotheses using 475 samples. First, as a result of analyzing the main effects of applying the structural equation model, role stress affected IS compliance intention through self-determination. Second, as a result of analyzing the moderating effect of applying Process 3.1, personal organization fit strengthened the relationship between self-determination and IS compliance intention. The research suggests a direction for achieving internal IS goals by confirming the influence of IS stress and behavioral causes of employees.

• Design Convergence Study
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• v.14 no.5
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• pp.157-169
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• 2015

In this study, three axillary crutches(Mobilegs, KM crutch, Pro In-motion) were tested with 12 healthy male subjects by measuring the EMG activity of the latissimus dorsi and gastrocnemius and the user-perceived levels focusing on the comfort and ease of use. The result showed that the EMG activity of the gastrocnemius was significantly reduced during ambulation using Mobilegs and Pro In-motion compared with the ambulation using KM crutch, a conventional crutch. However, no statistically significant difference was found for EMG activity of the latissimus dorsi. Subjects perceived the Mobilegs to be more comfortable and easy to use than the other crutches. Theses result may delivered mostly from the characteristics of spring-loaded axillary pad and ergonomic crutch handle. The results indicate that ambulation using the spring-loaded crutch is much easy with asking less exertion at gastrocnemius. In addition, the characteristics of crutch design, such as embedded spring, makes muscles to consume less energy. When the reasonable structure and form of the axillary pad and crutch handle are applied herein, the ambulation using the crutches are perceived to comfort.

• The Korean Journal of Franchise Management
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• v.9 no.4
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• pp.33-43
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• 2018

Purpose - In hotel industry, quality of leader-member exchange(LMX) relationship is very critical, because it impacts on the employee's work attitude and behaviors. Thus, this research examines the effect of LMX on employee loyalty in the context of hotel business and identifies mediating roles of work stressors, work role performance in the relationship between LMX and employee loyalty. This research suggests the guidelines for how hotel leaders should manage their employees and build employee loyalty that improve management and business performance. Research design, data, and methodology - This study tests the structural relationship between LMX, work stressors, work role performance, and employee loyalty. Work role performance divide into three sub-dimensions such as individual task proficiency, individual task adaptivity, and individual task proactivity. In order to examine the purposes of this research, research model and hypotheses were developed. All constructs were measured with multiple items developed and tested in the previous studies. The data were collected from 113 franchise hotel employees and were analyzed using SPSS 22.0 and SmartPLS 3 program. Result - The findings of this research are as follows. First, leader-member exchange(LMX) have significant positive impacts on work stressors, work role performance, and employee loyalty. Second, work stressors have significant negative impacts on work role performance and employee loyalty. Third, work role performance has significant positive impact on employee loyalty. Conclusions - The outcomes of this research indicate that hotel leaders should focus on the dyadic relationship with their employees how to improve employee productivity through LMX relationship. In turn, the quality of this relationship influences employees's work attitudes and behaviors. As a result of increasing job demands in hotel business which relies heavily on human resources, the hotel leader must find ways to prevent or reduce stressors and associated strains. If hotel employees perceive the high quality of LMX relationship, they improve their work role performance which influences loyalty. Therefore, the hotel leaders should develop monetary or non-monetary reward system for the employees and, make an efforts to have unique social exchange relationships with employees.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.367-374
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• 2006

This research revealed the operation problems of the current crossing control systems through inspecting and testing the obstacle detection systems and gate control systems for the crossings. To resolve the problems of the crossing control systems, this research developed new algorithms of four-quadrant gate system and obstacle detection systems combing the functions of rasar sensors and magnetic sensors and tested the reliability of the systems. Currently, the obstacle detection systems and gate control systems controls approaching and departing traffic by simply detecting vehicles and obstacles but do not consider traffic movements at the crossings. In addition, they do not make signal cooperation for gate controls. As a result, such inefficient crossing controls result in unsafe gate controls for drivers. Therefore, the newly developed crossing control systems through this study will provide more effective crossing control services with more strengthen information cooperation within control systems. Besides they will help to reduce train crashes at the crossings by gate control systems considering various driving behaviors.

• The Korea Journal of Herbology
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• v.39 no.3
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• pp.77-84
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• 2024

Objectives : Lysimachia mauritiana Lam. is known as a medicinal plant native to Korea that has antioxidant, anticancer, antibacterial, and antiviral activities. However, until now, research on the cultivation technology of L. mauritiana is insufficient, and there are no research data on the systematic cultivation method and mass production of L. mauritiana. Therefore, this study aims to establish a cultivation system of L. mauritiana. Methods : The cultivation environment of open land and facilities according to the growth of L. mauritiana was compared and tested. In addition, the equivalence of the origin collection extract and the cultivation extract was evaluated through Ultra high performance liquid chromatography (UHPLC) patterns analysis according to cultivation and comparison of the effect of inhibiting respiratory inflammation using BEAS-2B human bronchial epithelial cells. Results : The cultivation technology system was established through cultivation research of L. mauritiana raw materials. In addition, as a result of comparing and evaluating the equivalence of cultivated plants and L. mauritiana raw materials for suppressing respiratory inflammation, the same results were confirmed, and the equivalence was confirmed as a result of analyzing the UHPLC pattern with L. mauritiana raw materials. Conclusions : This study suggests that extract from cultivation research of L. mauritiana plants, which are native to Korea, can be used as a health functional food or medicine to improve respiratory health.

• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.2
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• pp.133-136
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• 2023

Purpose: Prolactin in the blood is separated into three types, and over 90% of prolactin presents as a double monomer (23 KDa). Rarely, it can exist in the size of big prolactin (150 KDa), which is called macroprolactin and is known as an autoantibody complex. When macroprolactin accounts for more than 60% of prolactin in the blood, it is called macroprolactinemia. The presence of such macroprolactin was first reported in a patient with hyperprolactinemia but without typical symptoms. Macroprolactinemia is emerging as an important cause of idiopathic hyperprolactinemia. The polyethylene glycol (PEG) precipitation method using the property of precipitating large-molecular-weight proteins is simple and recently has been widely used as a screening test. The results are in good agreement with the results of gel chromatography. The purpose of this study was to confirm the measurement method and reference value verification of monomeric prolactin in blood prolactin using the PEG precipitation method. Materials and Methods: For 40 examinees who visited the Gangnam Center of Seoul National University Hospital in 2021, the prolactin level was verified using radioimmunoassay (RIA). For macroprolactinemia PEG precipitation method, 25% PEG (molecular weight 6000kDa) solution and serum were mixed in equal amounts in a test tube, then left at room temperature for 20 minutes and centrifuged at 4℃ for 30 minutes (1500g). The prolactin level was measured in the supernatant. Results : After confirming that more than 90% of the 40 tested samples within the reference range <25 ng/mL, the same value as the reference value for prolactin was applied. Since the concentration of monomeric prolactin in serum from which macroprolactin has been removed from blood is diluted 1:1 with PEG, our laboratory is currently reporting the result by multiplying the result by a dilution factor of 2. Conclusion: Radioimmunoassay using PEG precipitation method using the property of precipitating large molecular weight proteins is simple and effective for quantitative measurement of monomeric prolactin in blood prolactin.

• Journal of the Earthquake Engineering Society of Korea
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• v.28 no.3
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• pp.121-128
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• 2024

There are growing concerns that the recently implemented Earthquake Early Warning service is overestimating the rapidly provided earthquake magnitudes (M). As a result, the predicted damages unnecessarily activate earthquake protection systems for critical facilities and lifeline infrastructures that are far away. This study is conducted to improve the estimation accuracy of M by incorporating the observed S-wave seismograms in the near source region after removing the site effects of the seismograms in real time by filtering in the time domain. The ensemble of horizontal S-wave spectra from at least five seismograms without site effects is calculated and normalized to a hypocentric target distance (21.54 km) by using the distance attenuation model of Q(f)=348f^0.52 and a cross-over distance of 50 km. The natural logarithmic mean of the S-wave ensemble spectra is then fitted to Brune's source spectrum to obtain the best estimates for M and stress drop (SD) with the fitting weight of 1/standard deviation. The proposed methodology was tested on the 18 recent inland earthquakes in South Korea, and the condition of at least five records for the near-source region is sufficiently fulfilled at an epicentral distance of 30 km. The natural logarithmic standard deviation of the observed S-wave spectra of the ensemble was calculated to be 0.53 using records near the source for 1~10 Hz, compared to 0.42 using whole records. The result shows that the root-mean-square error of M and ln(SD) is approximately 0.17 and 0.6, respectively. This accuracy can provide a confidence interval of 0.4~2.3 of Peak Ground Acceleration values in the distant range.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.197-204
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• 2006

Recently, in order to realization of construction and economical saving, various studies are progressing. Also, the study on RCS system which is consisted of reinforced concrete column and steel beam is progressing actively. Actually, however, resisting mechanism of panel zone is influenced by transverse beams when the stress transfers inner panel to outer panel but existing literature didn't reflect the effect of transverse beams. This paper is to analyze the test result of five inner beam-column joints specimen with a variable such as web, flange thickness of transverse beam and face bearing plate(FBP) for RCS systems were tested under cyclic loadings conforming to NEHRP recommendation to investigate the effect of transverse beams and the structural performance of beam-column joints. From the test result, it was shown that transverse beams are effective to enhance the shear strength and structural performance of beam-column joints.