• Journal of the Daesoon Academy of Sciences
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• v.42
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• pp.109-141
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• 2022

As many perhaps already know, in East Asian thought there are two aspects of all things such as light and darkness coexist and are called Yin-Yang (陰陽). The initial concept of Yin-Yang was just a simple expression meant to depict natural phenomena, but it gradually became the central concept in explanations of creation and the changes that undergo all things in the universe. The study of the ordering principle of nature that was known as Myeongli (命理) also examined the interrelation between the sky and the earth and divided the two into Ten Celestial Stems (天干 cheongan) and the Twelve Earth Branches (地支 jiji) based on Yin-Yang theory. This thesis analyzed contents of the relationship between Ten Celestial Stems and the Twelve Earth Branches in terms of the patterns of Mutual Aid (相助 sangjo) and Mutual Contention (相剋 sanggeuk) through a literature review and exploration of their common features and differences. Different categorized phenomena under the pattern of Mutual Aid include Tonggeun (通根 root downward) and Tugan (透干 appearance of the upward). Tonggeun means that signs in the Celestial Stems took root in their counterparts of the Earthly Branches. In the Celestial Stems, there is also Tonggeuncheo (通根處 a place to root downward) which in relation to the Earthly Branches show that the same five phases become Samhap (三合 combined three ways to gain power) and Banghap (方合 gathering in the same season). The methods of seeing Tonggeunryeok (通根力 power of a downward root) are as follows: First, it is seen by the places where Tonggeun takes hold. Ilgan (日干 the Celestial Stem of a birthday) is ordered as month (月 wol) > day (日 il) > hour (時 shi) > year (年 nyeon), and other Celestial Stems appear ordered as month > sitting > close place. Second, it can be seen by the characteristics of Earthly Branches that Tonggeun has taken hold. The Earthly Branches are ordered as Rokwangji (祿旺支 vigorous land) and Jangsaengji (長生支 newborn land) > Yeogi (餘氣 remaining energy) > Myogo (墓庫 storage and burial grounds). Tugan is the concept that the main agent was changed to Tonggeun, which means that the spirit of the Earthly Branches is manifested in the Celestial Stems. And the five phases hidden in the Earthly Branches will be able to play their roles as they are revealed. There are also the phenomena of Gaedu (蓋頭 the heavenly destroying the earthly) and Jeolgak (截脚 the earthly destroying the heavenly) which are concepts that convey that the Heavenly Stems and Earthly Branches can mutually destroy one another. There are different opinions on Gaedu because some adopt viewpoints of just focusing on the Celestial Stems and considering it only in terms the Celestial Stems destroying the Earthly Branches. But, the vast majority of scholars think that the Celestial Stems weakens the role of the roots by destroying the Earthly Branches. Jeolgak, the reverse concept of Gaedu, weakens the spirit of the Celestial Stems as the Earthly Branches destroy them, and this is associated with the strong possibility that one is fated to experience disharmony.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.131-134
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• 2014

본 연구의 목적은 직장인의 주관적 안녕감에 대한 업무 효능감/의미감의 역할을 조사하는 것이다. 이를 위해 본 연구는 긍정 정서, 부정 정서, 삶의 만족과 같은 주관적 안녕감의 구성요인들과 업무 효능감, 업무 의미감으로 구성된 이론모형을 제안하였다. 설문방법을 이용하여 자료를 수집하였고, 구조방정식모형을 사용하여 자료를 분석하였다. 분석결과 첫째, 예상대로 긍정 정서는 삶의 만족에 긍정적인 영향을 미치는 반면 부정 정서는 삶의 만족에 부정적인 영향을 미치는 것으로 나타났다. 둘째, 업무 효능감과 업무 의미감은 긍정/부정 정서와 삶의 만족 간의 관계를 매개하는 것으로 나타났다. 업무 효능감 및 의미감이 직장인의 행복감에 의미 있는 영향을 미친다는 본 연구의 결과는 조직 관리자들이 효과적인 지휘 전략을 수립하는데 기초 자료가 될 것으로 기대된다.

• Knowledge Management Research
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• v.16 no.4
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• pp.133-155
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• 2015

Smart Work is an extended version of telecommuting or distance work pursuing an objective of work-life balance which is one of the hottest issues in management research. With diffusion of Smart Work, a problem has been raised that Smart Work makes the boundary between work and non-work blur, and may break the balance of work-life. However, work-life balance will be achieved by actively managing the boundary between work and non-work rather than passively taking the consequences. In order to find out whether Smart work improves work-life balance, we need to understand the precedence factors influencing on job satisfaction and the role of boundary management strategy which Smart Workers actively choose. This paper considered the bi-directional permeability between work and non-work domain and developed a research model containing a causal relationship among three factors, job autonomy, job involvement, and job satisfaction, and the moderation effect of boundary management strategy. The results show that both job autonomy and job involvement affect job satisfaction and boundary management strategy which Smart Workers utilize plays a moderating role influencing on job satisfaction.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.38-43
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• 2014

In Ocean, the temperature of the deep sea water is always lower than that of the surface sea water. The temperature difference between the surface water and deep sea water is about $20^{\circ}C$. Based on thermodynamics, this temperature difference can be converted into mechanical power. The mechanical power can be converted to electricity through a generator. However, the temperature difference is relatively small compared with that of traditional steam turbines. It is difficult to apply the steam turbine technology for this small temperature difference directly. Therefore, the turbine for OTEC system using low temperature difference should be designed to meet the system requirement. The present study focuses on the development of the turbine for 20 kW OTEC system using R32. The paper includes the determination of working fluids, meridional design, turbine layout and 3D CFD results. With off-design points analysis, the full performance of 20kW OTEC turbine is investigated. Through the research, one stage radial type turbine with R32 as working fluid is successfully developed and can be applied to other high temperature heat source.

• Journal of the Korean institute of surface engineering
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• v.47 no.4
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• pp.147-154
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• 2014

Formation behavior of PEO (Plasma Electrolytic Oxidation) films on AZ31 Mg alloy was studied in aqueous solutions containing various concentrations of hydroxide ion ($OH^-$) and silicate ion ($SiO_3{^{2-}}$) by voltage-time curves, and corrosion resistance of the PEO film-covered specimen was investigated by immersion test in 0.5 M NaCl solution. From the analyses of the voltage-time curves, it is suggested that two different types of anions are essentially needed for the formation of PEO films on AZ31 Mg alloy: film formation agent and local film breakdown agent. $SiO_3{^{2-}}$ ion acts only as a film formation agent but $OH^-$ ion acts not only as a film formation agent but also film breakdown agent. The PEO films prepared on AZ31 Mg alloy in alkaline silicate solution showed very good corrosion resistance without any pitting or filiform corrosions up to 480 h of immersion in 0.5 M NaCl.

• Journal of the Korean institute of surface engineering
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• v.47 no.4
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• pp.155-161
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• 2014

The present work is concerned with the formation behavior of anodic oxide films on Al7075 alloy under a galvanostatic condition in 20 vol.% sulfuric acid solution. The formation behaviour of anodic oxide films was studied by the analyses of voltage-time curves and observations of colors, morphologies and thicknesses of anodic films with anodization time. Hardness of the anodic oxide films was also measured with anodization time and at different positions in the anodic films. Six different stages were observed with anodiziation time : barrier layer formation (stage I), pore formation (stage II), growth of porous films (stage III), abnormal rapid oxide growth (stage IV), growth of non-uniform oxide films (stage V) and breakdown of the thick oxide films under high anodic voltages (stage VI). Hardness of the anodic oxide films appeared to decrease with increasing anodization time and with the position towards the outer surface. This work provides useful information about the thickness, uniformity, imperfections and hardness distribution of the anodic oxide films formed on Al7075 alloy in sulfuric acid solution.

• Journal of the Korean Society of Visualization
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• v.18 no.2
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• pp.35-38
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• 2020

Airfryer is used to heat a food up by convecting hot air upward around the food. In this study, we investigated the effect of the bottom-shape of the food container in airfryer on the upward convection velocity of hot air to find an optimal bottom-shape by computational fluid dynamics. Numerical experiments were performed by solving the incompressible Navier-Stokes equations with turbulence model. We found that the maximum upward velocity with concave flow-passage on the bottom was bigger than that with the flat bottom and that the maximum upward convection velocity was achieved when the number of concave flow-passage with fan-shape is around six. The pressure drop by the internal flow was found to increase as the number of the concave flow-passage on the bottom increased probably due to increase of the surface area of the bottom. Therefore, it can be said that the optimal number of the concave flow-passage is around six for the flow rate considered in this study.

• Journal of Digital Convergence
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• v.11 no.1
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• pp.191-198
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• 2013

The interests in alternative office systems and solutions (called smart work in Korea) are growing. With the lens of boundary theory, this paper tries to understand the nature of work/nonwork boundaries which smart work will be expected to blur. Boundary theory provides permeability, boundary strength, and interference as its key concepts and an empirical study is performed about the individual perception on those concepts. The result of the survey from telecommuters and/or smart work center users at the Company K shows that they perceive work/nonwork permeability, boundary strength, and interference are asymmetric. The result suggests that asymmetric nature of the work/nonwork boundaries should be taken into account when alternative office systems are brought into use.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.881-888
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• 2017

In general, the choking phenomenon occurs by flow acceleration for a turbine at high pressure ratio condition. In choking condition, total pressure ratio increases without mass flow rate variation. It is hard to predict choking characteristics by using conventional meanline analysis which used mass flow inlet boundary condition. In the present study, the algorithm for predicting choking point is developed to solve the problem. Moreover, performance estimation algorithm after choking is presented by reflecting the flow behaviour of flow expansion at choked nozzle or rotor. The analysis results are compared with 3D CFD analysis and experimental data to validate present method.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.20-28
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• 2018

In general, the choking phenomenon occurs due to the flow acceleration of a turbine under high pressure-ratio. During choking, the total pressure ratio increases without any variation in the mass flow rate. It is difficult to predict choking characteristics by using conventional meanline analysis, which utilizes mass flow inlet boundary condition. In this study, an algorithm for predicting the choking point is developed to solve this problem. In addition, a performance estimation algorithm is presented to estimate the performance after choking, based on the flow behavior of flow expansion at the choked nozzle or rotor. The analysis results are compared with 3D CFD analysis and experimental data to validate this method.