• Communications for Statistical Applications and Methods
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• 제30권6호
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• pp.577-587
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• 2023

Conventional categorical data imputation techniques, such as mode imputation, often encounter issues related to overestimation. If the variable has too many categories, multinomial logistic regression imputation method may be impossible due to computational limitations. To rectify these limitations, we propose a two-stage imputation method. During the first stage, we utilize the Boruta variable selection method on the complete dataset to identify significant variables for the target categorical variable. Then, in the second stage, we use the important variables for the target categorical variable for logistic regression to impute missing data in binary variables, polytomous regression to impute missing data in categorical variables, and predictive mean matching to impute missing data in quantitative variables. Through analysis of both asymmetric and non-normal simulated and real data, we demonstrate that the two-stage imputation method outperforms imputation methods lacking variable selection, as evidenced by accuracy measures. During the analysis of real survey data, we also demonstrate that our suggested two-stage imputation method surpasses the current imputation approach in terms of accuracy.

• International journal of advanced smart convergence
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• 제13권1호
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• pp.152-161
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• 2024

The purpose of this study sought to determine the impact of shared leadership perceived by organizational members on team effectiveness and team learning behavior. For this purpose, the results of the empirical analysis of 206 organizational members are as follows. First, shared leadership was analyzed to improve team effectiveness. Second, shared leadership had a positive effect on team learning behavior. Third, team learning behavior was statistically significantly analyzed for team effectiveness. This study confirmed the importance of shared leadership, which has a positive impact on team effectiveness and team learning behavior. This may require building a new culture that can demonstrate the inherent leadership of organizational members in the influence relationship between shared leadership, team effectiveness, and team learning behavior. In other words, in order to systematically demonstrate and implement shared leadership, the execution ability of executives, managers, and working-level managers is important. To this end, it is necessary to build an organizational culture that matches the characteristics of the organization and develop and continuously implement human resource development systems and programs that can implement this.

• International journal of advanced smart convergence
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• 제13권1호
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• pp.1-11
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• 2024

Cognitive small cell networks, consisting of macro-cells and small cells, are foreseen as a promising candidate solution to address 5G spectrum scarcity. Recently, many technological issues (such as spectrum sensing, spectrum sharing) related to cognitive small cell networks have been studied, but the common control channel (CCC) establishment problem has been ignored. CCC is an indispensable medium for control message exchange that could have a huge significant on transmitter-receiver handshake, channel access negotiation, topology change, and routing information updates, etc. Therefore, establishing CCC in cognitive small cell networks is a challenging problem. In this paper, we propose a potential game theory-based approach for CCC establishment in cognitive radio networks. We design a utility function and demonstrate that it is an exact potential game with a pure Nash equilibrium. To maintain the common control channel list (CCL), we develop a CCC update algorithm. The simulation results demonstrate that the proposed approach has good convergence. On the other hand, it exhibits good delay and overhead of all networks.

• 센서학회지
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• 제33권3호
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• pp.147-151
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• 2024

The importance of Wireless Sensor Networks is becoming more evident owing to their practical applications in various areas. However, the energy problem remains a critical barrier to the progress of WSNs. By reducing the energy consumed by the sensor nodes that constitute WSNs, the performance and lifespan of WSNs will be enhanced. In this study, we introduce an energy-efficient ternary modulator that employs multi-threshold CMOS for logic conversion. We optimized the design with a low-power ternary gate structure based on a pass transistor using the MTCMOS process. Our design uses 71.69% fewer transistors compared to the previous design. To demonstrate the improvements in our design, we conducted the HSPICE simulation using a CMOS 180 nm process with a 1.8V supply voltage. The simulation results show that the proposed ternary modulator is more energy-efficient than the previous modulator. Power-delay product, a benchmark for energy efficiency, is reduced by 97.19%. Furthermore, corner simulations demonstrate that our modulator is stable against PVT variations.

• 대한수학회논문집
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• 제21권1호
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• pp.145-149
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• 2006

We demonstrate a novel almost Kahler deformation on $\mathbb{R}^4$ which diffuses the scalar curvature.

• Journal of the Korean Statistical Society
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• 제7권2호
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• pp.99-100
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• 1978

This note is to demonstrate that the extention of Theorem 4.15 of Graybill on the independence of quadratic forms is possible. For the self-contained exposition, Theorem 4.15 is rewritten.

• 한국간호교육학회지
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• 제4권2호
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• pp.331-342
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• 1998

Nurses evaluate the physical, emotional, and spiritual well-being of a person when conducting an assessment and forming a plan of care. Nursing is a holistic approach to health and well-being. Implication for Nursing Practice : nurses must assess and support intrinsic religiosity and promote spiritual well-being in peoples coping with severe diseaser. The purpose of this study was to investigate spiritual well-being, hope and self-esteem of nursing students, and to identify spiritual well-being, hope and self-esteem the differences between nursing students of christian university and nursing students of non-christian university. The measurment tools for spiritual well-being, hope anf self-esteem were a self-report questionnaire. The collected data was prepared for computer analysis and analyzed using appropriate statistical methods. General characteristics, spiritual well-being, hope and self-esteem are analyzed by descriptive statistical methods. For hypothesis testing t-test, Pearson correlation are used. The result of this study can be summarized as follows ; 1. The mean score for spiritual well-being in the nursing students was 79.52 of a possible range of 20-120. And the mean score for hope was 58.18 of a possible range of 29-116, the mean score for self-esteem was 112.29 of a possible range of 30-150. 2. 'Nursing students of christian university will demonstrate higher spiritual well-being than the nursing students of nonchristian university' was rejected(t=1.01, p=.96). 3. 'Nursing students of christian university will demonstrate higher hope than the nursing students of nonchristian university' was rejected(t=1.71, p=.05). 4. 'Nursing students of christian university will demonstrate higher self-esteem than the nursing students of nonchristian' was rejected(t=1.53, p=.12). 5. 'The higher spiritual well-being, the higher hope' was rejected(r=-.664, p=.000). 6. 'The higher spiritual well-being score, the higher self-esteem' was supported(r=.487, p=.000).

• IMMUNE NETWORK
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• 제15권2호
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• pp.73-82
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• 2015

Respiratory syncytial virus (RSV) infection is recognized by the innate immune system through Toll like receptors (TLRs) and retinoic acid inducible gene I. These pathways lead to the activation of type I interferons and resistance to infection. In contrast to TLRs, very few studies have examined the role of NOD-like receptors in viral recognition and induction of adaptive immune responses to RSV. Caspase-1 plays an essential role in the immune response via the maturation of the proinflammatory cytokines IL-$1{\beta}$ and IL-18. However, the role of caspase-1 in RSV infection in vivo is unknown. We demonstrate that RSV infection induces IL-$1{\beta}$ secretion and that caspase-1 deficiency in bone marrow derived dendritic cells leads to defective IL-$1{\beta}$ production, while normal RSV viral clearance and T cell responses are observed in caspase-1 deficient mice following respiratory infection with RSV. The frequencies of IFN-${\gamma}$ producing or RSV specific T cells in lungs from caspase-1 deficient mice are not impaired. In addition, we demonstrate that caspase-1 deficient neonatal or young mice also exhibit normal immune responses. Furthermore, we find that IL-1R deficient mice infected with RSV exhibit normal Th1 and cytotoxic T lymphocytes (CTL) immune responses. Collectively, these results demonstrate that in contrast to TLR pathways, caspase-1 might not play a central role in the induction of Th1 and CTL immune responses to RSV.

• 한국축산식품학회지
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• 제30권5호
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• pp.787-794
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• 2010

Calcium plays a role as a signaling molecule in various cellular events. It has been reported that calcium suppresses adipocyte differentiation only in the early phase of adipogenesis. Herein, we demonstrate that treatment of A23187, a mobilizer of intracellular calcium, on day 4 post adipocyte differentiation could still reduce lipid accumulation in differentiating 3T3-L1 cells for 48 h. In addition, luciferase reporter gene and RT-Q-PCR assays demonstrate that A23187 can selectively inhibit transcriptional activities and expression of PPAR$\gamma$ and LXR$\alpha$, suggesting that A23187 may reduce lipid accumulation in the late phase of adipogenesis via downregulation of PPAR$\gamma$ and LXR$\alpha$ expression and transactivation. Moreover, inhibition of HDAC activity by trichostatin A (TSA) partially blocked A23187-mediated downregulation of transcriptional activities of PPAR$\gamma$ and LXR$\alpha$. Together, our data demonstrate that calcium mobilization inhibits expression and transcriptional activities of PPAR$\gamma$ and LXR$\alpha$, resulting in reduced lipid accumulation in differentiating adipocytes, and thus, mobilization of intracellular calcium in adipocytes may serve as a new preventive and therapeutic approach for obesity.

• 혜화의학회지
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• 제26권1호
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• pp.1-10
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• 2017

Objectives: The aim of this study is (1) to investigate the historic changes and pharmacological efficacies of Woohwangchungsim-won and (2) to discuss the necessities for Woohwangchungsim-won's clinical applications. Methods: This study was performed through (1) investigating the ancient literature records related with Woohwangchungsim-won and analyzing Woohwangchungsim-won's composition, dosage and indications, (2) searching articles about Woohwangchungsim-won on 10 major Korean web and 3 major foreign web article search engines and analyzing Woohwangchungsim-won's pharmacological efficacies and indications. Results: Woohwangchungsim-wom has been used for cerebrovascular diseases such as stroke and palpitation. Also, there are some ancient literature records of Woohwangchungsim-won's clinical applications in neuropsychiatric disorders such as depression and bipolar disorder. In addition, there have been a number of experimental studies which demonstrate Woohwangchungsim-won's neuroprotective effect on cerebral cortex and hippocampus injury. So, it is possible to infer that Woohwangchungsim-won can be used for the treatments of neuropsychiatric disorders associated with neuronal cell death in cerebral cortex and hippocampus. But there have been no or less experimental studies which demonstrate the pharmacological efficacy of Woohwangchungsim-won on such disease. Conclusion: It is necessary that further experimental studies which demonstrate Woohwangchungsim-won's pharmacological efficacy on neuropsychiatric disorders should be done and Woohwangchungsim-won's clinical applications should be expanded on the basis of those related experimental results.