• Korea Trade Review
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• v.46 no.2
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• pp.75-92
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• 2021

There is increasing awareness in the international alliance literature that the firm performance effects of the alliance portfolio go beyond the effects of the individual alliances. I enrich this nascent perspective by developing a alliance portfolio composition framework based on the alliance portfolio dimensions - underpinned by the simultaneity of quantitative and qualitative factors in international portfolio - that enhances firms' financial performance. This paper assesses the impact on firm performance of composing the alliance dimension within a firm's international alliance portfolio. In an unbalanced panel data analysis with fixed effects of the performance of 502 firms operating in the Korean manufacturing industry during 2011-2017, I test whether firm's three dimension of international alliance portfolio affect on firm financial performance. I find that the intensity of international alliance have significantly positive effect on the firm performance. And following the moderating analysis of three portfolio dimension-functional, relational, and attribute, all of each three international alliance portfolio has positive moderating effects on the relationship between the alliance intensity and firm performance. These results indicate that firms should consider and form simultaneous approaches to exploit the international alliance based on the alliance portfolio dimensions with intensity of alliance portfolio.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4395-4407
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• 2023

Bubble columns are widely encountered in several industries, especially in the field of nuclear safety. The Eulerian-Eulerian and the Eulerian-Lagrangian methods are commonly used to investigate bubble columns. Eulerian approaches require additional tasks such as strict volume conservation at the interface and a predefined well-structured grid. In contrast, the Lagrangian approach can be easily implemented. Hence, we introduce a fully Lagrangian approach for the simulation of bubble columns using the discrete bubble model (DBM) and moving particle semi-implicit (MPS) methods. Additionally, we propose a rigorous method to estimate the volume fraction accurately, and verified it through experimental data and analytical results. The MPS method was compared with the experimental data of Dambreak. The DBM was verified by analyzing the terminal velocity of a single bubble for each bubble size. It agreed with the analytical results for each of the four drag correlations. Additionally, the improved method for calculating the volume fraction showed agreement with the Ergun equation for the pressure drop in a packed bed. The implemented MPS-DBM was used to simulate the bubble column, and the results were compared with the experimental results. We demonstrated that the MPS-DBM was in quantitative agreement with the experimental data.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.117-129
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• 2024

This paper introduces collective navigation through a narrow gap using a curriculum-based deep reinforcement learning algorithm for a swarm of unmanned aerial vehicles (UAVs). Collective navigation in complex environments is essential for various applications such as search and rescue, environment monitoring and military tasks operations. Conventional methods, which are easily interpretable from an engineering perspective, divide the navigation tasks into mapping, planning, and control; however, they struggle with increased latency and unmodeled environmental factors. Recently, learning-based methods have addressed these problems by employing the end-to-end framework with neural networks. Nonetheless, most existing learning-based approaches face challenges in complex scenarios particularly for navigating through a narrow gap or when a leader or informed UAV is unavailable. Our approach uses the information of a certain number of nearest neighboring UAVs and incorporates a task-specific curriculum to reduce learning time and train a robust model. The effectiveness of the proposed algorithm is verified through an ablation study and quantitative metrics. Simulation results demonstrate that our approach outperforms existing methods.

• Journal of Digestive Cancer Research
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• v.12 no.1
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• pp.23-30
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• 2024

Borderline resectable pancreatic cancer, an intermediate stage between a completely resectable state and an unresectable state, requires a multidisciplinary treatment approach. This study aimed to elucidate the main characteristics and recent research trends regarding borderline resectable pancreatic cancer to gain further insights into them. Data from published papers about borderline resectable pancreatic cancer were collected from Web of Science (2014-2023) for the analysis. This study included 355 papers; data on major countries, publishing organizations, and keywords were collected and analyzed. Furthermore, R studio and VOSviewer were used for the qualitative and quantitative analyses of keywords. Publication of papers on borderline resectable pancreatic cancer was observed to be increasing annually by 12.8%, with the United States and Japan being the main publishing countries. In 2014, keywords related to surgery and chemotherapy were dominant; however, a shift toward more integrative approaches, such as neoadjuvant therapy, was observed over time. This study demonstrates rapidly evolving trends and paradigm changes in the research and management of borderline resectable pancreatic cancer. Thus, the results of this study are expected to contribute to establishing future research strategies and improving patient treatment outcomes.

• International Journal of Stem Cells
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• v.16 no.3
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• pp.304-314
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• 2023

Background and Objectives: Ear cartilage malformations are commonly encountered problems in reconstructive surgery, since cartilage has low self-regenerating capacity. Malformations that impose psychological and social burden on one's life are currently treated using ear prosthesis, synthetic implants or autologous flaps from rib cartilage. These approaches are challenging because not only they request high surgical expertise, but also they lack flexibility and induce severe donor-site morbidity. Through the last decade, tissue engineering gained attention where it aims at regenerating human tissues or organs in order to restore normal functions. This technique consists of three main elements, cells, growth factors, and above all, a scaffold that supports cells and guides their behavior. Several studies have investigated different scaffolds prepared from both synthetic or natural materials and their effects on cellular differentiation and behavior. Methods and Results: In this study, we investigated a natural scaffold (alginate) as tridimensional hydrogel seeded with progenitors from different origins such as bone marrow, perichondrium and dental pulp. In contact with the scaffold, these cells remained viable and were able to differentiate into chondrocytes when cultured in vitro. Quantitative and qualitative results show the presence of different chondrogenic markers as well as elastic ones for the purpose of ear cartilage, upon different culture conditions. Conclusions: We confirmed that auricular perichondrial cells outperform other cells to produce chondrogenic tissue in normal oxygen levels and we report for the first time the effect of hypoxia on these cells. Our results provide updates for cartilage engineering for future clinical applications.

• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.645-651
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• 2018

The carcinogenicity of chemicals in the environment is a major concern. Recently, numerous studies have attempted to develop methods for predicting carcinogenicity, including rodent and cell-based approaches. However, rodent carcinogenicity tests for evaluating the carcinogenic potential of a chemical to humans are time-consuming and costly. This study focused on the development of an alternative method for predicting carcinogenicity using quantitative PCR (qPCR) and colon cancer stem cells. A toxicogenomic method, mRNA profiling, is useful for predicting carcinogenicity. Using microarray analysis, we optimized 16 predictive gene sets from five carcinogens (azoxymethane, 3,2'-dimethyl-4-aminobiphenyl, N-ethyl-n-nitrosourea, metronidazole, 4-(n-methyl-n-nitrosamino)-1-(3-pyridyl)-1-butanone) used to treat colon cancer stem cell samples. The 16 genes were evaluated by qPCR using 23 positive and negative carcinogens in colon cancer stem cells. Among them, six genes could differentiate between positive and negative carcinogens with a p-value of ${\leq}0.05$. Our qPCR-based prediction system for colon carcinogenesis using colon cancer stem cells is cost- and time-efficient. Thus, this qPCR-based prediction system is an alternative to in vivo carcinogenicity screening assays.

• Journal of Oral Medicine and Pain
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• v.38 no.4
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• pp.367-372
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• 2013

To diagnose sensory nerve damage, patient values for thermal stimuli as quantitative sensory test (QST) can be compared with the values of the general population (absolute reference data) or to values measured at contralateral unaffected side (relative reference data). It is well know that relative reference data are more sensitive for detecting sensory abnormality than absolute reference data. However it is still lack of the studies for comparisons between relative and absolute data. This study aimed to evaluate the validity of relative reference data and compare the sensitivities of the two approaches in the orofacial region. In 19 young Korean women as normal subjects, quantitative somatosensory thermotest were done in the forehead, cheek, mentum, lower lip and tongue tip bilaterally. After we get the standard deviations (SD) of average reference data and relative reference data, the ratios SD absolute data/SD relative data were calculated. Our study showed that relative reference data for side to side comparisons in the same patient have the high ratios than the absolute reference data, i.e. the side to side comparisons with relative reference data exhibit gain in sensitivity in assessment of sensory abnormality.

• The Journal of the Convergence on Culture Technology
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• v.1 no.4
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• pp.27-43
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• 2015

The objective of this study is to find out the construct of intellectual capital in a fashion company. To this end, the mixed research methods that combined qualitative and quantitative approaches were conducted. Qualitative research was first conducted by in-depth interviews with 16 experts working in the fashion industry, and a questionnaire was then given to 121 fashion companies in order to fulfill the quantitative research portion of this study. The findings of this study are as follows: First, the conceptual structure of intellectual capital in a fashion company was revealed. A fashion company's intellectual capital is composed of 'human capital', 'structural capital', and 'relational capital'. Human capital has three components: a chief executive officer (CEO), members, and a human resource management capability. Structural capital has four components: organizational culture, information management capability, merchandising capability, and product innovation capability. Relational capital has three components: customer equity, marketing capability, and relationship management capability. Second, the conceptual structure of intellectual capital was confirmed via quantitative research analysis. All of the components of intellectual capital have internal consistency, convergent validity, construct validity, and discriminant validity.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.194-204
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• 2020

Cultivar parameters, which are key inputs to a crop growth model, have been estimated using observation data in good quality. Observation data with high quality often require considerable labor and cost, which makes it challenging to gather a large quantity of data for calibration of cultivar parameters. Alternatively, data in sufficient quantity can be collected from the reports on the evaluation of cultivars by region although these data are of questionable quality. The objective of our study was to assess the quality of crop and management data available from the reports on the regional adaptation trials for rice cultivars. We also aimed to propose the measures for improvement of the data quality, which would aid reliable estimation of cultivar parameters. DatasetRanker, which is the tool designed for quantitative assessment of the data for parameter calibration, was used to evaluate the quality of the data available from the regional adaptation trials. It was found that these data for rice cultivars were classified into the Silver class, which could be used for validation or calibration of key cultivar parameters. However, those regional adaptation trial data would fall short of the quality for model improvement. Additional information on management, e.g., harvest and irrigation management, can increase the quantitative quality by 10% with the minimum effort and cost. The quality of the data can also be improved through measurements of initial conditions for crop growth simulations such as soil moisture and nutrients. In addition, crop model improvement can be facilitated using crop growth data in time series, which merits further studies on development of approaches for non-destructive methods to monitor the crop growth.

• Management & Information Systems Review
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• v.32 no.1
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• pp.289-309
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• 2013

Social enterprise has moved from periphery to take center stage. Social enterprises are a truly global phenomenon and associated with solving social problems with business approaches. While the numbers of social enterprises have grown and their impact is likely to continue to do so, it would be dangerous to assume that the revolutionary momentum will automatically continue, because social enterprise faced sustainability challenges. This study collected the data from directory of Korean Social Enterprise to conduct a quantitative research on the growth of social enterprise in South Korea. This study conducted longitudinal analysis of 491 social enterprise certified between 2007 and 2010, of economic performance with financial index and social impact with employment structure. Though global financial crisis, Korean social enterprises show that there is a considerable increase in all of quantitative and qualitative aspects. Korean social enterprises have provided meaningful work to those normally excluded from the labour market and tried to raise their life of working. In the future, Korean social enterprises should find a way to balance social and financial performance and ensure the sustainability of the business.