• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.131-140
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• 2013

Econometric forecast models based on past time-series data have been applied to a wide variety of applications due to their advantages in short-term point estimating. These models are particularly used in predicting the impact of governmental research and development (R&D) programs because program managers should assert their feasibility due to R&D program's huge amount of budget. The construction governmental R&D programs, however, separately make an investment by dividing total budget into five sub-business area. It make R&D program managers difficult to understand how R&D programs affect the whole system including economy because they are restricted with regard to many dependent and dynamic variables. In this regard, system dynamics (SD) model provides an analytic solution for complex, nonlinear, and dynamic systems such as the impacts of R&D programs by focusing on interactions among variables and understanding their structures. This research, therefore, developed SD model to capture the different impacts of five construction R&D sub-business by considering different characteristics of sub-business area. To overcome the SD's disadvantages in point estimating, this research also proposed the method for constructing quantitative forecasting model using qualitative data. Understanding the different characteristics of each construction R&D sub-business can support R&D program managers to demonstrate their feasibility of capital investment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.768-774
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• 2010

A parametric study is conducted for the segmented arc plasma torch with the input power and current of 0.4 MW and 300 A, respectively. For this purpose, we use the analytical relationship equations between plasma temperature, inner diameter (R) and length (L) of the torch constrictor at the given input power and current conditions based on the arc channel model. The results reveal that arc plasma temperatures show non-linear behavior or absence corresponding to the variations of L and R when their values become larger than 1.25 m and 7.5 mm, respectively. For L < 1.25 m and R < 7.5 mm, however, they can increase monotonically as L increase or R decrease when one of both parameters is fixed. From these parametric study results, optimum ranges of R and L are suggested as $5.5mm{\leq}R{\leq}7.0mm$ and $0.5m{\leq}L{\leq}1.0m$ for 0.4 MW class segmented arc plasma torch, under which stable arc plasma with the temperatures of ~15,000 K can be achived at the input currents of ~300 A.

• Journal of the Korean Magnetics Society
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• v.21 no.4
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• pp.121-126
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• 2011

Spin dynamics of magnetic tunnel junctions with free and fixed reference layers is investigated by ferromagnetic resonance micromagnetic simulations. First, in magnetic tunnel junctions with an exchange biased synthetic ferrimagnetic reference layer, a magnetization direction of each layer and the tunneling magnetoresistance are calculated for a DC magnetic field. To investigate the spin exciting modes in magnetic tunnel junctions, we simulate the ferromagnetic resonance frequency spectra with small RF magnetic fields. Exciting modes of the tunneling magnetoresistance calculated by an included angle between free and reference layers is interpreted from those of each layer. Spin exciting modes are different according to a signs of the DC magnetic field. In a negative magnetic field, FMR frequency spectra of free and reference layers are well elucidated by the modified Kittel's equation. However, in a positive magnetic field, there is no simple analytic solution related to FMR frequency spectra due to the coupled modes. Since ferromagnetic layers in magnetic tunnel junctions are interactive each other, careful considerations of the reference and fixed layer as well as the free layer are required for understanding on the spin dynamics of magnetic tunnel junctions with an exchange biased synthetic ferrimagnetic reference layer.

• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.393-400
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• 2011

The residential complexes in waterfront provide the residents with pleasantness and comfort with their scenety and view in the surrounding watersides. However, it is currently true that there has little been established any designing plan utilizing the environmental characteristics of the waterfront. In this study, a survey was conducted on the residents of a Japanese waterfront. in Nishimiyahama and Lake Biwa, and conducted a comparative and analytic investigation regarding water-friendly activities, residents' consciousness of the housing environment, and reasons for the choice of residenve. From the results, we were able to obtain some suggestive points resulting from the differences of the aforementioned. We also fully comprehended that there are some issues and needs for solution for the environmental characteristics in the waterfront as well as for the damage incurred by salt breeze and insects. In addition, we realized that scenery and view toward watersides are becoming the important factors in the residents' consciousness regarding the housing environment. In case of planning housing complexes located in the waterfront, we keenly understood that "the size of a room", "ventilation", "view and daily lighting", and "securing privacy" are having effects on the residents' consciousness of their housing.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.6
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• pp.387-396
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• 2010

A 3-D numeric model for the confined transient flow under sea ground have been developed. This is FDM model using Gauss-Seidel SOR (successive over-relaxation). This model shows the similar head distribution pattern to Theis analytic solution and MODFLOW simulation. The input flowrate to the aquifer and discharge of well have been compared. And it have been found that mass balance is influenced by the weight factor ${\alpha}$, i.e. fullyimplicit method (${\alpha}$=1) shows 5% error, but when ${\alpha}$ becomes to 0.5(Crank and Nicolson method) the mass balance becomes worse and the model result diverges. And the convergency of the model is not much different when $\lambda$ (over-relaxation factor)=0.8~1.5, but when $\lambda$>1.5, the model result diverges. The test-run shows that the well discharge becomes smaller when another well is near. This model can cover the isotropy$(Kx{\neq}Ky{\neq}Kz)$ and inhomogeneity, and can be used for the selection of well site, discharge calculation, and head prediction in case of the artificial recharge etc.

• Archives of design research
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• v.17 no.3
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• pp.335-342
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• 2004

Recently there have been various research activities regarding Korean traditional aesthetics. However, those researches were mainly conducted individually, partially, and periodically, which resulted in unsystematic and incomprehensive works. Therefore, it is required to orginze all the precedent research works with more systematic and objective framework. Generally speaking, all the human activities including aesthetic activity have ends, procedure and means. In other words, human being needs three key elements for realizing any thought and those three elements include contents, formal, and practical element. Element of contents is ultimate goal to accomplish as value, concept, and meaning of thought with their aims. Formal element includes methods, principles, norms, procedure, formality and style comprising of thought in order to accomplish the goal. Finally, practical element refers to specific means, tool, media, material and techniques to concretize the contents through form. Almost all of thoughts and meaning which human being tries to express consist of language. Major elements in sentence include 'subject (omissible)' , 'objects (aim)', 'predicate (formality)', 'complement (means)' and they are composed systematically and hierarchically with rules in sentence. The study compared human activity model with language structure and analyzed their implication with design (aesthetics), which made it possible to propose analytic frameworks for traditional aesthetics. In addition, the study also systematically organized the way to realize traditional aesthetic value in the present context based on the methods developed in this study.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.3
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• pp.583-590
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• 2007

The significance of Han medicine (韓醫學), the Korean traditional medicine, that has lasted throughout the past couple millenniums relies upon Han Philosophy distinguished by its uniqueness. In brief, the specificity of Han medicine is characterized by unity of spirit and body, part and whole. According to this theory, when curing a frozen shoulder, it is usually cured by acupuncturing the area around the part that aches, but also doing so on the area that is totally different from the aching part such as the opposite part of the body. In fact, this can be pursued only through aspects that enable one to realize the unity of part and whole, and a ground for this possibility bases upon the crux of Eastern Philosophy, I-ching(역), such as theory of Five Elements (음양오행) and Three Pillars(삼재). In Western set theory, the issues of Class(부류) and elements(요원), whole and part were independently discussed in the area of mereology, and the question of part and whole was encountered with aporia and paradox since Greek ancient philosophy. At the turn of this century, many philosophers endeavored to pursue academic inquiry to resolve this paradox, especially by Russell and Whitehead through ${\ll}$Principia Mathematica${\gg}$ at the beginning of this century. in the process, there came out a phrase 'Russell's Paradox'. Russell himself proposed a typological resolution as an answer to the inquiry. However, 'Russell's Paradox' still remains as an aporia even till present days. During medieval period, this inquiry was even considered as 'insolubia'. Throughout this paper, 1 attempt to provide an analytic aspect on 'Russell's Paradox' from an unique thinking method and perspective of Han medicine that embodies the concept of 'unity of part and whole'. To do so, 1 suggest a physiological model in the first place depicted by diagrams of Circle 원, Quadrangle 방, Triangle 각(CQT) that portray the logic of Hado or Hotu 하도 which is 'the pattern from the river Ho'. That is to suggest that CQT원방각 of Hado can De a logical foundation that explains the notions of spirit (정신,뇌), internal organs(장부), and meridian system which functions as a solution to the question of 'Russell's Paradox'. There are precedent academic works examining the issue from philosophical aspect such as Sangil Kim's ${\ulcorner}$Han medicine과 러셀역설 해의${\lrcorner}$ Han Medicine and Resolution of Russell's Paradox(2005), and this analysis will further attempt to critically examine such works from a perspective of Han medicine.

• Journal of the Korea Society for Simulation
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• v.30 no.1
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• pp.11-20
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• 2021

As unmanned underwater systems have recently emerged, a high-speed underwater channel modeling technique, which is one of the most important techniques in the system, has received a lot of attention. In this paper, we proposed a high-speed sound propagation model and verified the applicability through quantitative performance analyses. We used a high-order finite difference method (FDM) for wave propagation modeling in the water, and a domain decomposition method was adopted using multiple general-purpose graphics processing units (GPUs) to increase the calculation efficiency. We compared the results of the model we proposed with the analytic solution in the half-infinite media and results of the Virtual Timeseries Experiment (VirTEX) model, which is based on the ray method. Finally, we analyzed the performance of the model quantitatively using numerical examples. Through quantitative analyses of the improvement in computational performance, we confirmed that the computational speed increases linearly as the number of GPUs increases. The computation times are increased by 2 times and 8 times, respectively, when the domain size of computation and the maximum frequency are doubled. We expect that the proposed high-speed underwater channel modeling technique is able to contribute to the enhancement of national defense as an underwater communication channel model and analysis tool to develop the underwater communication technique for the unmanned underwater system.

• Journal of Korea Port Economic Association
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• v.37 no.4
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• pp.13-31
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• 2021

Since the signing of the Korea-Europe Free Trade Agreement, the volume of trade transactions between South Korea and Europe has increased. The traditional single-mode transport system has been transformed into an intermodal transport system using two or more modes of transport. In addition, the conventional sea and air transport routes have been restricted, leading to a decline in Korean exports to Europe, and the rail transport mode is becoming mainstream in the market due to the influence of COVID-19. This paper focuses on the China-Railway Express to explore a new intermodal transport route from Korea to Europe. First, the fuzzy analytic hierarchy process (AHP) is used to evaluate the factor weights when selecting intermodal transport routes from Korea to Europe. Then, the TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method is used to rank three alternatives. The results show that among the four factors (total cost, total time, transportation capability, and service reliability), the total cost is the most significant factor, followed by the total time, service reliability, and transportation capability. Furthermore, the alternative route 1 (Incheon-Dalian-Manchuria-Hamburg) is preferred.

• Journal of Korean Society for Quality Management
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• v.50 no.4
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• pp.647-664
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• 2022

Purpose: The purpose of this study is to derive major policies that domestic small and medium-sized manufacturing companies should consider to maximize productivity and quality improvement by utilizing manufacturing data and AI, and to find priorities and implications. Methods: In this study, domestic and international issues and literature review by country were conducted to derive major considerations such as manufacturing AI technology, manufacturing AI talent, manufacturing AI data and manufacturing AI ecosystem. Additionally, the questionnaire survey targeting 46 experts of manufacturing data and AI industry were conducted. Finally, the major considerations and detailed factors importance were derived by applying the Analytic Hierarchy Process (AHP). Results: As a result of the study, it was found that 'manufacturing AI technology', 'manufacturing AI talent', 'manufacturing AI data', and 'manufacturing AI ecosystem' exist as key considerations for domestic manufacturing AI. After empirical analysis, the importance of the four key considerations was found to be 'manufacturing AI ecosystem (0.272)', 'manufacturing AI data (0.265)', 'manufacturing AI technology (0.233)', and 'manufacturing AI talent (0.230)'. The importance of the derived four viewpoints is maintained at a similar level. In addition, looking at the detailed variables with the highest importance for each of the four perspectives, 'Best Practice', 'manufacturing data quality management regime, 'manufacturing data collection infrastructure', and 'manufacturing AI manpower level of solution providers' were found. Conclusion: For the sustainable growth of the domestic manufacturing AI ecosystem, it should be possible to develop and promote manufacturing AI policies in a balanced way by considering all four derived viewpoints. This paper is expected to be used as an effective guideline when developing policies for upgrading manufacturing through domestic manufacturing data and AI in the future.