• Bulletin of the Korean Chemical Society
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• v.22 no.11
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• pp.1255-1260
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• 2001

The expansion of two different kinds of hydrodynamic size of polymethyl methacrylate (PMMA Mw: 1.56- 2.04 ${\times}$ 106 g/mol) has been measured by dynamic light scattering and viscometry above the Flory $\theta$ temperature of the variou s solvents such as n-butyl chloride, 3-heptanone, and 4-heptanone. The expansion of PMMA chains was analyzed in terms of universal temperature parameters and also compared with previous results of polystyrene (PS) system. First it was found that simple $\tau/{\tau}c$ parameter no longer had its universality for the expansion behavior of hydrodynamic size in the chemically different linear polymer chains. However after modifying ${\tau}/{\tau}c$ parameter into $(Mw/Ro2)3}2(\tau/\tauc)$, we observed a much better universality for both PMMA and PS systems. Here Mw, Ro, $\tau[=(T-{\theta}$)/${\theta}$]$, and ${\tau}c[=({\theta}-Tc)/Tc]$ are defined as the weight average molecular weight, the unperturbed end-to-end distance, the reduced temperature and the reduced critical temperature, respectively.

• Computers and Concrete
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• v.20 no.6
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• pp.689-704
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• 2017

The paper presents experimental and numerical investigations of prefabricated composite structural building reinforced concrete slabs with the insulating material for a residential building construction. The building slabs were composed of concrete and expanded polystyrene. In experiments, the slabs in the full-scale 1:1 were subjected to vertical concentrated loads and failed along a diagonal shear crack. The experiments were numerically evaluated using the finite element method based on two different constitutive continuum models for concrete. First, an elasto-plastic model with the Drucker-Prager criterion defined in compression and with the Rankine criterion defined in tension was used. Second, a coupled elasto-plastic-damage formulation based on the strain equivalence hypothesis was used. In order to describe strain localization in concrete, both models were enhanced in the softening regime by a characteristic length of micro-structure by means of a non-local theory. Attention was paid to the formation of critical diagonal shear crack which was a failure precursor.

• Archives of Plastic Surgery
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• v.48 no.4
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• pp.384-388
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• 2021

Adequate positioning of the hand is a critical step in hand fracture operative repair that can impact both the clinical outcome and the efficiency of the operation. In this paper, we introduce the use of a thermoplastic splint with an added thumb stabilizing component as a means to increase the surgeon's autonomy and to streamline the patient care pathway. The thermoplastic splint is custom fabricated preoperatively by the specialist hand therapist. The splint is used prior, during, and post operation with minimal modification. The thumb component assists maintaining the forearm in a stable pronated position whilst drilling and affixing metal work. This is demonstrated in the video of removal of metal work and open reduction and internal fixation of a metacarpal fracture.

• Communications for Statistical Applications and Methods
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• v.28 no.4
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• pp.351-368
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• 2021

For a probabilistic model with positively skewed data, a lognormal distribution is one of the key distributions that play a critical role. Several lognormal models can be found in various areas, such as medical science, engineering, and finance. In this paper, we propose a new estimator for a lognormal mean and depict the performance of the proposed estimator in terms of the relative mean squared error (RMSE) compared with Shen's estimator (Shen et al., 2006), which is considered the best estimator among the existing methods. The proposed estimator includes a tuning parameter. By finding the optimal value of the tuning parameter, we can improve the average performance of the proposed estimator over the typical range of σ². The bias reduction of the proposed estimator tends to exceed the increased variance, and it results in a smaller RMSE than Shen's estimator. A numerical study reveals that the proposed estimator has performance comparable with Shen's estimator when σ² is small and exhibits a meaningful decrease in the RMSE under moderate and large σ² values.

• Tuberculosis and Respiratory Diseases
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• v.82 no.3
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• pp.179-189
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• 2019

Although recent advances in molecular targeted therapy and immuno-oncology have revolutionized the landscape of lung cancer therapeutics, cytotoxic chemotherapy remains an essential component of lung cancer treatment. Extensive evidence has demonstrated the clinical benefit of chemotherapy, either alone or in combination with other treatment modalities, on survival and quality of life of patients with early and advanced lung cancer. Combinational approaches with other classes of anti-neoplastic agents and new drug-delivery systems have revealed promising data and are areas of active investigation. Chemotherapy is recommended as a standard of care in patients that have progressed after tyrosine kinase inhibitors or immune checkpoint inhibitors. Chemotherapy remains the fundamental means of lung cancer management and keeps expanding its clinical implication. This review will discuss the current position and future role of chemotherapy, and specific consideration for its clinical application in the era of precision medicine.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.103-116
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• 2021

In this work, a model of a functionally graded (FG) nanotube conveying fluid embedded in an elastic medium is developed based on the nonlocal strain gradient theory (NSGT) in conjunction with Euler-Bernoulli beam theory (EBT). The main objective of this research is to investigate the nonlinear vibration and stability analysis of fluid-conveying nanotubes. The governing equations of motion are derived by means of Hamiltonian principle. The analytical expressions of nonlinear frequencies and critical flow velocities for two different types of boundary conditions including pinned-pinned (P-P) and clamped-clamped (C-C) conditions are obtained by employing Galerkin method as well as Hamiltonian Approach (HA). Comparison of the obtained results with the published works show the acceptable accuracy of the current solutions. The effects of the power-law index, the nonlocal and material length scale parameters and the elastic medium on the stability and nonlinear responses of FG nanotubes are thoroughly investigated and discussed.

• Korean journal of applied entomology
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• v.31 no.3
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• pp.304-313
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• 1992

The agricultural industry is beset by continuing demands to decrease the use of pest control agents which employ toxic modes of action. Although there are real problems of pesticide resistance, and sometimes overuse or redistribution in the environment, much criticism results from a lack of appreciation of how small is the risk involved. Whatever the background reasons, research and development for pesticide alternatives, particularly within Integrated Pest Management systems, is clearly of high priority. Currently available approaches, including use of natural products and molecular biology, are often regarded with naive optimism and require critical appraisal. For the future, methods of pest control based on chemicals with non-toxic modes of action (e.g. pheromones) continue to offer promise but, for widespread use, will require their integration with biological agents and development by means of plant molecular biology.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.341-346
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• 2005

After the IMF shock, some major construction companies in Korea have been motivated to avoid and mitigate various risk factors which could be critical and catastrophic events to corporate revenue and organization internally or externally. It means that they are trying to introduce and set up a risk management plan and system suitable to their organization and culture. L construction co. ltd. is one of major construction companies that have been searching methodologies or technologies to manage various risk factors surrounding corporate marketing and project operation. This paper presents an unique approach to develop a model of risk management plan and system suitable to L construction itself focused on the construction phase.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.463-467
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• 2015

Mega-shock means a sporadic event such as the earning shock, which occurred by sudden market changes, and it can cause serious problems of profit loss of international construction projects. Therefore, the early response and prevention by analyzing and predicting the Mega-shock is critical for successful project delivery. This research is preliminary study to develop a prediction model that supports market condition analysis and Mega-shock forecasting. To avoid disadvantages of classic statistical approaches that assume the market factors are linear and independent and thus have limitations to explain complex interrelationship among a range of international market factors, the research team explored the Fractal Theory that can explain self-similarity and recursiveness of construction market changes. The research first found out correlation of the major market factors by statistically analyzing time-series data. The research then conducted a base of the Fractal analysis to distinguish features of fractal from data. The outcome will have potential to contribute to building up a foundation of the early shock warning system for the strategic international project management.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1376-1379
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• 2009

Recently many Hotels have implemented and operated the Hotel Information System(HIS). These HIS-implementation evoke the significant changes in hotel management. So many interest and researches in HIS has received the spotlight from the hotel managements. Many researcher about HIS focused on the Critical Success Factors (CSF) from the viewpoint of HIS implementation. At this moment we need also the research about significance change of CSF with the laps of time. This kind of research are very critical for the successful operation of HIS. To achieve the objectives of this paper, the Innovation-Theory of E. M. Roger was implemented. As the result of this research we can get the various maturity point of each CSF with the laps of time. For the data gathering many major hotel in Korea were interviewed, and 84 valid questionaires were used for data analysis. The Cronbach's ${\alpha}$ was 0.7239, which means all data were significant.