• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2382-2390
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• 2007

A new polynomial-based predistortion method for linearizing nonlinear power amplifier is proposed. The proposed method finds the predistortion parameter directly without the help of postdistorter whereas most existing polynomial-based predistortion methods calculate the predistortion parameter indirectly from the prostdistorter. First, a new predistortion algorithm is derived based on the assumption that the characteristic of the amplifier is modeled by piecewise linear function. Then it is modified into a proposed method which does not require any assumption or prior knowledge of the amplifier. The proposed method is derived based on the RLS (recursive least squares) algorithm. The proposed technique is simpler to implement than the existing methods and the computer simulation demonstrates that the proposed method is more robust to the initial condition and the saturation region of the amplifier.

• Geomechanics and Engineering
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• v.18 no.6
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• pp.595-603
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• 2019

A modified model combining Kriging and Monte Carlo method (MC) is proposed for probabilistic estimation of tunnel face stability in this paper. In the model, a novel uniform design is adopted to train the Kriging, instead of the existing active learning function. It has advantage of avoiding addition of new training points iteratively, and greatly saves the computational time in model training. The kinematic approach of limit analysis is employed to define the deterministic computational model of face failure, in which the Hoek-Brown failure criterion is introduced to account for the nonlinear behaviors of rock mass. The trained Kriging is used as a surrogate model to perform MC with dramatic reduction of calls to actual limit state function. The parameters in Hoek-Brown failure criterion are considered as random variables in the analysis. The failure probability is estimated by direct MC to test the accuracy and efficiency of the proposed probabilistic model. The influences of uncertainty level, correlation relationship and distribution type of random variables are further discussed using the proposed approach. In summary, the probabilistic model is an accurate and economical alternative to perform probabilistic stability analysis of tunnel face excavated in spatially random Hoek- Brown media.

• Journal of Engineering Education Research
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• v.22 no.3
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• pp.32-40
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• 2019

This paper deals with the effects of teamwork competence on problem solving ability through the mediating effect of creative personality for the engineering students. For this purpose, a regression-based statistical mediation analysis has been performed for a simple mediation model in which teamwork competence and problem solving ability were treated as independent and dependent variables respectively, and creative personality was included as a mediation variable. The analysis results showed that the teamwork competence has direct effect on the problem solving ability as well as indirect effect through the creative personality. This result implies that the problem solving ability can be improved directly by improving the teamwork competence, and moreover, it can be further improved indirectly or through the mediation effect by improving the creative personality. Thus, in order to develop excellent problem solving ability, it is necessary to form team members in a balanced way between teamwork competence and creative personality in the team-based learning.

• Journal of Korean language education
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• v.29 no.4
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• pp.201-223
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• 2018

The purpose of this study is to observe the effects of text modification by comparing differences in Korean reading comprehension levels that arise from differences in vocabulary levels in texts. This study intends to use simplified texts with the vocabulary difficulty adjusted differently from the original text to measure reading comprehension levels of Korean learners and analyze the result. To measure reading comprehension, the researcher divided 55 Korean learners of intermediate to advanced level of fluency into two groups; the control group read the original text and the treatment group read a simplified text in which complex vocabulary were substituted with easier words of medium difficulty. Then the two groups were tested with the same questionnaire to measure comprehension levels of each group. The result showed that the groups that read simplified texts scored higher than the control group; this suggests that the reading comprehension level was increased in the treatment group. The experiment confirmed that unknown vocabulary density has direct impact on Korean reading comprehension. The result shows that the proportion of unknown vocabulary should be reduced for meaning-focused reading. It also demonstrates that comprehension of the learner was enhanced with lexical simplification rather than structural simplification i.e. simplification of grammar or sentences. Thus, diverse reading materials adjusted to the learners' level of fluency should be developed to enable reading for learning Korean. By reducing the burden of understanding the meaning of each vocabulary, learners will be able to achieve the initial goal of reading.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.494-513
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• 2019

A multi-channel access problem based on hypergraph model in ultra-dense small cell networks is studied in this paper. Due to the hyper-dense deployment of samll cells and the low-powered equipment, cumulative interference becomes an important problem besides the direct interference. The traditional binary interference model cannot capture the complicated interference relationship. In order to overcome this shortcoming, we use the hypergraph model to describe the cumulative interference relation among small cells. We formulate the multi-channel access problem based on hypergraph as two local altruistic games. The first game aims at minimizing the protocol MAC layer interference, which requires less information exchange and can converge faster. The second game aims at minimizing the physical layer interference. It needs more information interaction and converges slower, obtaining better performance. The two modeled games are both proved to be exact potential games, which admit at least one pure Nash Equilibrium (NE). To provide information exchange and reduce convergecne time, a cloud-based centralized-distributed algorithm is designed. Simulation results show that the proposed hypergraph models are both superior to the existing binary models and show the pros and cons of the two methods in different aspects.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.479-486
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• 2021

This study aims to explore the relationships between strategic planning, strategic maneuverability, and firm performance in the current dynamic business environment. It employs a quantitative research method and reports on a survey, using a questionnaire, of service companies in Indonesia's oil and gas industry. Of the 337 companies selected by simple random sampling from a vendor database, responses were received from 70 companies. The analysis was performed using Partial Least Square Structural Equation Modeling and SmartPLS software. The analysis consisted of descriptive statistics, evaluation of the measurement model, evaluation of the structural model, and hypotheses testing. The results show that both strategic planning and strategic maneuverability have a positive relationship with firm performance. In addition, there is a positive relationship between strategic planning and firm performance through the mediating role of strategic maneuverability. The findings suggest that the organizational agility, organizational flexibility, and organizational responsiveness that constitute strategic maneuverability have a positive direct and indirect effect on firm performance, namely financial performance, customer performance, internal process performance, and learning and growth. This study contributes to the strategic management literature and the theory of maneuvers by providing empirical evidence on the relationship between strategic planning, strategic maneuverability, and firm performance.

• Journal of Korea Multimedia Society
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• v.24 no.2
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• pp.285-294
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• 2021

This study developed a responsive healthcare system that users can easily use in real life to prevent turtle neck syndrome by posture correction. We propose a system that naturally induces direct posture improvement by adjusting the height with a responsive cradle through a turtle neck discrimination algorithm detecting the turtle neck posture in real time using a webcam. The turtle neck algorithm was developed based on machine learning, using the points that the distance relationship between the jaw line and the shoulder varies depending on the posture. For the younger age group, which is particularly problematic due to the increase in the use of IT devices, image data in different situations according to the height and posture of the cradle was collected and learned as a support vector machine classifier. In addition, a height-adjustable cradle that can support a laptop has been created and expanded into a responsive cradle that can be controlled with software by interlocking with the Arduino. Therefore, this service enables posture correction of many modern people suffering from turtle neck syndrome and will become an essential platform in the increasing online environment in the non-contact era.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.289-306
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• 2021

This paper aims to investigate how and to what extent FDI impacts the relative demand for skilled labor within firms in the case of developing countries. The analysis uses a sizeable micro-level dataset for Malaysian manufacturing industries using the System-GMM estimators to control the estimations' endogeneity problems. For this purpose, the study uses foreign equity share at the firm level to investigate foreign ownership effects at the firm level and the Horizontal FDI index by Smarzynska Javorcik (2004) to analyze FDI intra-industry linkages influence on the structure of labor demand for Malaysian domestic firms. Our findings indicate that foreign ownership increases the skilled demand within Malaysian manufacturing through the learning process, exclusively for small- and medium-sized firms (SMEs). Conversely for foreign-owned firms, changes in their skilled-labor share do not associate with changes in firm-level foreign equity share. We conclude that foreign ownership per se is not the major contributing factor for skill upgrading in Malaysian manufacturing firms. Furthermore, the competitive pressures caused by foreign firms' presence within the same industry - namely horizontal FDI - has a significant negative spillover effect on the level of skilled-labor share for domestic firms in the Malaysian manufacturing sector within periods of the understudies.

• Journal of Korean Public Health Nursing
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• v.36 no.1
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• pp.47-58
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• 2022

Purpose: This study was undertaken to present an effective plan for the development of an educational program and a strategy to promote patient safety management activities for nursing students by identifying factors that affect these activities based on the theory of planned behavior. Methods: A self-report questionnaire was distributed to 300 nursing students who had clinical practice experience at three nursing colleges in Daejeon, Gyeongbuk, and Jeonbuk. The significance of the model fit, and the path effect was confirmed by confirmatory factor analysis. Results: The hypothetical model for patient safety management activities was appropriate. Among the 5 pathways, 4 were significant. It was found that behavioral intention had a direct influence on patient safety management activities, and perceived behavioral control and attitude had an influence on behavioral intention. Conclusion: To strengthen the perceived behavioral control of nursing students' patient safety management activities, it is necessary to analyze and remove obstacles and provide education that reflects the characteristics of the subject's health problems. In addition, through self-directed learning involving simulation practice, nursing students should be exposed to patient safety accidents, so that they can recognize the risks early and solve problems through critical thinking while bringing about the necessary changes in their attitude.

• Journal of Interdisciplinary Genomics
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• v.4 no.2
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• pp.24-30
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• 2022

Klinefelter's syndrome (KS) is a syndrome with extra X chromosome(s), in XY individuals, characterized by gynecomastia, small testes, and infertility. Additional X chromosomes can be present as variable karyotypic forms, including mosaicism (47,XXY/46,XY). The reported prevalence of KS ranges from one in 500 to one in 1,000 live males, but is probably underestimated. The classic phenotype is small, firm testes and infertility resulting from seminiferous tubule dysgenesis and androgen deficiency. The spectrum of KS includes tall stature with relatively long legs and arm span, decreased body hair, learning disabilities, behavioral problems, poor motor skills, and other important medical issues, such as metabolic syndrome, diabetes, autoimmune diseases, cardiovascular disease, certain neoplasia. The increased risk of certain medical problems in KS can be attributed to a direct effect of the extra X chromosome, the combined action of multiple genomic and epigenetic factors, or the hormonal imbalances. Typically, chromosome analysis is not ordered for adult patients with general medical conditions, except for suspected cases of hematologic and lymphoid disorders. Even though it was found during work-up for certain disorders in adult patient, most physicians do not suspect KS or consider its impact. Therefore, understanding the pathophysiology and variable manifestation in KS is necessary, and discussions with multidisciplinary teams will help to diagnose and treat males with KS.