• Child Health Nursing Research
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• v.19 no.2
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• pp.130-139
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• 2013

Purpose: In this study an examination was done of the effects of a adolescent smoking cessation motivational program on smoking temptation, internal motivation, stage of smoking cessation and quit rate. The study was done with a nonequivalent control group pretest-posttest design. Methods: Participants in the experimental group were adolescents who smoked and were referred to the program by their high school teachers. They participated in the smoking cessation motivational program for 60 minutes per session, once or twice a week for six weeks. Participants in the control group were selected from the same age group within the school and the program was provided after the posttest was completed. t-test, Mann-Whitney test, and ${\chi}^2$-test were used to analyze data. Results: The level of smoking temptation, internal motivation and stage of smoking cessation had significant change in comparison to the pretest whereas the control group did not exhibit these changes. Conclusion: The results of the study indicate that a smoking cessation motivational program for adolescents is an effective strategy to increase smoking cessation motivation in adolescents, and can be utilized as an effective intervention for adolescents who smoke.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.1
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• pp.11-17
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• 2013

'Multi-scale mass-deployable cooperative robots' is a next generation robotics paradigm where a large number of robots that vary in size cooperate in a hierarchical fashion to collect information in various environments. While this paradigm can exhibit the effective solution for exploration of the wide area consisting of various types of terrain, its technical maturity is still in its infant state and many technical hurdles should be resolved to realize this paradigm. In this paper, we propose to develop new design and manufacturing methodologies for the multi-scale mass-deployable cooperative robots. In doing so, we present various fundamental technologies in four different research fields. (1) Adaptable design methods consist of compliant mechanisms and hierarchical structures which provide robots with a unified way to overcome various and irregular terrains. (2) Soft composite materials realize the compliancy in these structures. (3) Multi-scale integrative manufacturing techniques are convergence of traditional methods for producing various sized robots assembled by such materials. Finally, (4) the control and communication techniques for the massive swarm robot systems enable multiple functionally simple robots to accomplish the complex job by effective job distribution.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.747-754
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• 2021

Purpose: Seismic safety evaluation of a curved bridge must be performed since the curved bridges exhibit the complex behavior rather than the straight bridges, due to geometrical characteristics. In order to conduct the probabilistic seismic assessment of the curved bridge, Seismic fragility evaluation was performed using the uncertainty of the steel material properties of a curved bridge girde, in this study. Method: The finite element (FE) model using ABAQUS platform of the curved bridge girder was constructed, and the statistical parameters of steel materials presented in previous studies were used. 100 steel material models were sampled using the Latin Hypercube Sampling method. As an input ground motion in this study, seismic fragility evaluation was performed by the normalized scale of the Gyeongju earthquake to 0.2g, 0.5g, 0.8g, 1.2g, and 1.5g. Result: As a result of the seismic fragility evaluation of the curved girder, it was found that there was no failure up to 0.03g corresponding to the limit state of allowable stress design, but the failure was started from 0.11g associated with using limit state design. Conclusion: In this study, seismic fragility evaluation was performed considering steel materials uncertainties. Further it must be considered the seismic fragility of the curved bridge using both the uncertainties of input motions and material properties.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.6
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• pp.417-426
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• 2021

Recently, use of the precast concrete (PC) system, which can increase economy by minimizing field work, has rapidly increased. However, the PC system cannot exhibit structural performance under construction, specifically before integration between members. Furthermore, since it is difficult to secure the structural integrity of beam-column joints even after construction, the PC system is vulnerable to progressive collapse. In the PC system, various types of details for PC beam-column joints have been proposed, while the structural/construction details of PC system generally used in Korea differ from those of overseas PC systems. However, studies on the progressive collapse of the domestic PC system are limited. Thus, in this study, we investigated the structural/construction details of PC beam-column joints mainly used in Korea. Based on the investigation, for the prototype PC system with typical joint details, a nonlinear finite element analysis was carried out to evaluate its structural performance under progressive collapse. Further, a parametric study was performed, and the effect of the design parameters was investigated, to recommend a method to improve the progressive collapse resistance of the PC system.

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.1
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• pp.19-37
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• 2024

Rockbolts are the primary-supports in NATM tunnels and are widely used at tunnel construction sites. Among the rockbolts methods applied in domestic tunnel design, fully grouted rockbolts are the most representative and frequently used. Fully grouted rockbolts exhibit relative behavior between the bolt and the ground due to the grout material. However, during numerical analysis for tunnel design, fully grouted rockbolts are often modeled in a way that does not reflect their behavior characteristics. This may result in underestimating or overestimating the force of the supports. Based on a literature review, it was analyzed that fully grouted rockbolts are modeled using truss element or cable element. To analyze the effect of grout properties of cable elements on rockbolts behavior, this paper compared the behavior of rockbolts in two models: one estimating grout properties based on rockbolt pull-out test data, and another assuming complete adhesion between the rockbolts and the ground by applying large grout properties. Under identical tunnel conditions, the numerical analysis was conducted by modeling the fully grouted rockbolts differently using truss and cable elements, and the tunnel behavior was analyzed. The research results suggest that modeling fully grouted rockbolts as a function of the interface effect between the bolts and the ground, specifically considering grout, is desirable. The use of pull-out test data to simulate the behavior of actual fully grouted rockbolts was considered as a valid approach.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.5
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• pp.77-90
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• 2023

This study aims to investigate the potential of alternative credit assessment through Social Networking Sites (SNS) as a complementary tool to conventional loan review processes. It seeks to discern the impact of SNS usage characteristics and loan product attributes on credit loan repayment. To achieve this objective, we conducted a binomial logistic regression analysis examining the influence of SNS usage patterns, loan characteristics, and personal attributes on credit loan conditions, utilizing data from Company A's credit loan program, which integrates SNS data into its actual loan review processes. Our findings reveal several noteworthy insights. Firstly, with respect to profile photos that reflect users' personalities and individual characteristics, individuals who choose to upload photos directly connected to their personal lives, such as images of themselves, their private circles (e.g., family and friends), and photos depicting social activities like hobbies, which tend to be favored by individuals with extroverted tendencies, as well as character and humor-themed photos, which are typically favored by individuals with conscientious traits, demonstrate a higher propensity for diligently repaying credit loans. Conversely, the utilization of photos like landscapes or images concealing one's identity did not exhibit a statistically significant causal relationship with loan repayment. Furthermore, a positive correlation was observed between the extent of SNS usage and the likelihood of loan repayment. However, the level of SNS interaction did not exert a significant effect on the probability of loan repayment. This observation may be attributed to the passive nature of the interaction variable, which primarily involves expressing sympathy for other users' comments rather than generating original content. The study also unveiled the statistical significance of loan duration and the number of loans, representing key characteristics of loan portfolios, in influencing credit loan repayment. This underscores the importance of considering loan duration and the quantity of loans as crucial determinants in the design of microcredit products. Among the personal characteristic variables examined, only gender emerged as a significant factor. This implies that the loan program scrutinized in this analysis does not exhibit substantial discrimination based on age and credit scores, as its customer base predominantly consists of individuals in their twenties and thirties with low credit scores, who encounter challenges in securing loans from traditional financial institutions. This research stands out from prior studies by empirically exploring the relationship between SNS usage and credit loan repayment while incorporating variables not typically addressed in existing credit rating research, such as profile pictures. It underscores the significance of harnessing subjective, unstructured information from SNS for loan screening, offering the potential to mitigate the financial disadvantages faced by borrowers with low credit scores or those ensnared in short-term liquidity constraints due to limited credit history a group often referred to as "thin filers." By utilizing such information, these individuals can potentially reduce their credit costs, whereas they are supposed to accrue a more substantial financial history through credit transactions under conventional credit assessment system.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.292-307
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• 2019

Buddhists have always tended to adorn and embellish Buddhist statues and their surrounding spaces in order to exhibit the grandeur and sublime nature of the Buddha. The various kinds of splendid instruments and implements used in such ornamentation are collectively called jangeomgu in Korean. Thus, the term jangeomgu encompasses articles used to decorate Buddhist statues, halos, and baldachin, as well as Buddhist banners and wind chimes, which are generally hung outside a building. Wind chimes are still widely used at Buddhist temples. In China, judging from various structures such as the Wooden Stupa of Yongningsi in Luoyang and the Dunhuang Caves, wind chimes began to be used around the sixth century. As for Korea, Buddhism was first introduced from China during the Three Kingdoms Period, and Koreans accordingly began to build Buddhist temples and buildings. It would appear that wind chimes came to be used around the time that the first temples were built. The oldest extant wind chime in Korea is the gilt-bronze wind chime of Baekje, discovered at the Mireuksa Temple Site in Iksan. In general, Korean wind chimes dating from the Three Kingdoms Period are classified into two general types according to their shape and elevation, i.e., those shaped like a Buddhist bell and those shaped like a trapezoid. As these two forms of wind chimes have influenced each other over time, those made during the Goryeo dynasty, having inherited the style, structure, and design of the preceding period, display such features. At the same time, the artisans who produced wind chimes pursued technical development and adopted free, yet not extravagant, designs. In particular, Goryeo wind chimes are characterized by original designs created through exchanges with other Buddhist art forms of the same period, such as the embossed lotus design band of Goryeo bells; the bullmun design, which served to display the grandeur of the royal family; the samhwanmun design, which consisted of decorating the interior of a Goryeo incense burner with three holes; Sanskrit designs; and designs inspired by the windows and doors of stone pagodas. In this way, the production of Goryeo wind chimes developed with a focus on purpose while being free of formal constraints. This study started out from the fact that the largest number of Korean wind chimes were produced during the Goryeo dynasty. Therefore, research on wind chimes should be based on those of the Goryeo dynasty, especially since fewer relevant studies have been conducted compared to studies on other forms of Buddhist art. For the purposes of this study, the reasons for the production of wind chimes will be examined first, followed by an examination of the various styles of Korean wind chimes. Then, based on the findings of this investigation, the development and characteristics of the wind chimes produced during the Goryeo dynasty will be explored for each period.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.3 s.151
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• pp.458-469
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• 2006

The purpose of this study was to prove that interchange is a primary factor in costume changes through case analysis in costume culture interchange, and further, to assist in gaining understanding of costume changes of the present and the future, and therefore, in this study, cases analysis was conducted focusing on interchange resulting from political factors. In order to present theories that are able to analyse costume culture interchange, culture, cultural exchange, and costume cultures were examined, and based on the results, a costume culture interchange process model and its three steps, propagation, selection, and reinterpretation, were presented. The results of case study on costume culture interchange resulting from political factors based on the costume culture interchange process model presented are as follows. Interchanges that politically uses the possibility of expressing costume as symbols are in most cases aggressive and semi aggressive. In order to exhibit superiority of themselves, the aggressors forced their national costumes onto the receiving culture. Rather than a simple introduction of their costumes, it was an attempt to introduce they values and their ways of life. The conclusion that can be reached through such result is that interchange is an important driving force for changes in costume culture. All interchanges were not greatly affected by methods of propagation and acceptance, and resulted in fusion. Fusion is a process in which existing costume and foreign costume come together constructively to for a new costume culture therefore change in costume style is inevitable.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.55-55
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• 2009

Silicon Carbide (SiC) is a material with a wide bandgap (3.26eV), a high critical electric field (~2.3MV/cm), a and a high bulk electron mobility (${\sim}900cm^2/Vs$). These electronic properties allow high breakdown voltage, high frequency, and high temperature operation compared to Silicon devices. Although various SiC DMOSFET structures have been reported so far for optimizing performances. the effect of channel dimension on the switching performance of SiC DMOSFETs has not been extensively examined. In this paper, we report the effect of the interface states ($Q_s$) on the transient characteristics of SiC DMOSFETs. The key design parameters for SiC DMOSFETs have been optimized and a physics-based two-dimensional (2-D) mixed device and circuit simulator by Silvaco Inc. has been used to understand the relationship with the switching characteristics. To investigate transient characteristic of the device, mixed-mode simulation has been performed, where the solution of the basic transport equations for the 2-D device structures is directly embedded into the solution procedure for the circuit equations. The result is a low-loss transient characteristic at low $Q_s$. Based on the simulation results, the DMOSFETs exhibit the turn-on time of 10ns at short channel and 9ns at without the interface charges. By reducing $SiO_2/SiC$ interface charge, power losses and switching time also decreases, primarily due to the lowered channel mobilities. As high density interface states can result in increased carrier trapping, or recombination centers or scattering sites. Therefore, the quality of $SiO_2/SiC$ interfaces is important for both static and transient properties of SiC MOSFET devices.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.171.2-171.2
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• 2016

The 2-dimensiona electron gas (2DEG) layers have opened tremendous interests in the heterooxide interfaces formed between two insulating materials, especially between LaAlO3 and $SrTiO_3$. The 2DEG layers exhibit extremely high mobility and carrier concentrations along with metallic transport phenomena unlike the constituent oxide materials, i.e., $LaAlO_3$ and $SrTiO_3$. The current work inserted artificially the interfacial layer, $Sr_xCa_{1-x}TiO_3$ between $LaAlO_3$ and $SrTiO_3$, with the aim to controlling the 2-dimensional transports. The insertion of the additional materials affect significantly their corresponding electrical transports. Such features have been probed using DC and AC-based characterizations. In particular, impedance spectroscopy was employed as an AC-based characterization tool. Frequency-dependent impedance spectroscopy have been widely applied to a number of electroceramic materials, such as varistors, MLCCs, solid electrolytes, etc. Impedance spectroscopy provides powerful information on the materials system: i) the simultaneous measurement of conductivity and dielectric constants, ii) systematic identification of electrical origins among bulk-, grain boundary-, and electrode-based responses, and iii) the numerical estimation on the uniformity of the electrical origins. Impedance spectroscopy was applied to the $LaAlO_3/Sr_xCa_{1-x}TiO_3/SrTiO_3$ system, in order to understand the 2-dimensional transports in terms of the interfacial design concepts. The 2-dimensional conduction behavior system is analyzed with special emphasis on the underlying mechanisms. Such approach is discussed towards rational optimization of the 2-dimensional nanoelectronic devices.