• Polymer(Korea)
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• v.29 no.1
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• pp.96-101
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• 2005

Fluoropolymer of PTFE and PFA etc. is a heat resistance polymeric material that it is known as that maximum continuous use temperature reaches for 260 $^{\circ}C$. It was observed that these polymers had the enough thermal stability so enough that it was kept by thermal aging of 280 $^{\circ}C$/7 weeks too in this study. However, such thermal stability means that bulk material property is kept such as mechanical strength, melting point and initial pyrolysis temperature etc. If these polymers are evaluate by coating property such as surface contact angle, surface morphology, surface scratch, thing that heat resistance is not enough was confirmed in this study. Thermal aging of flouropolymer coating was achieved by gear aging oven that the exchange rate of air was controlled, and the analysis results were indicating serious damage of surface morphology and adhesive strength on metal substrate.

• Journal of Korean Medical classics
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• v.29 no.1
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• pp.77-97
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• 2016

Objectives : Yiyuan(醫原) written by Shi Shoutang(石壽棠) is well known for its focusing on the concept of dryness and dampness in medical theory. This study was done to analyze the formation process of main academic thought in Yiyuan, which included tracing its original sources that had made it possible to construct the main idea in this book. Methods : Firstly, Yiyuan was analyzed in comparison with Yili(醫理) by Yu Guopei(余國佩), which is regarded as the main origin of Yiyuan. And secondly, many diverse medical theories before Yu Guopei and Shi Shoutang was scrutinized to understand the process of the construction of dryness/dampness-centered medical theory. Results & Conclusions : Shi Shoutang took over the main idea of Yu Guopei and expanded it both in theoretical and clinical aspects. Especially, the most remarkable contribution by Shi Shoutang can be said that he used the astronomical theory which had the concept of multi-layered heaven and intensified the theoretical basis of medical theory emphasizing the significance of dryness and dampness. Besides, Shi Shoutang's medical theory was a thing which was also based on many cumulative assertions about dryness and dampness before him. Yu Jiayan's assertion on dryness and dampness could be acknowledged as the most influential one, and it also could be said that the arguments surrounding the property of dryness had formed the main question in the development of medical theory centered on dryness and dampness.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2007.05a
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• pp.255-259
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• 2007

Contemporary society is a digital and information-oriented society and a change by digital and information-oriented has made a new society principle and creature. The principle and creature has made society changed having influence on office space. The 21st century business space attachs great importance to the public space as the value of work place, namely, the place of gathering and client meeting which is society space and a thing which grants it with the biggest investment worth is a new order. This kind of society change has been making an appearance in contemporary office space as features of Narrative, Nodal, Neighbourly, Nomadic. These kinds of trends which are not exclusive mutually are stipulated as new trials to business space holding a lot of overriding features in common. These kinds of features brought into relief according to society change can be seen as key words speaking for contemporary office space and have a significance to contemplate and study for the office space of a new concept made an appearance together with society change. It is expected to contribute to revitalization programs with the far-reaching effect of understanding about ideal office work circumstances and work shape which the 21st century wants standing on the features of these new concepts.

• Convergence Security Journal
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• v.16 no.7
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• pp.121-127
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• 2016

Recently, the popularity of smart devices such as Wi-Fi and LTE has increased the use ratio of wireless dramatically. On the other hand, the use ratio of wired internet is decreasing. The IoT(Internet of Things) is not only for people but also for communication between people and things, and communication between things and things by connecting to a wireless without choosing a place. Along with the rapid spread of the IoT there is a growing concern about the threat of IoT security. In this paper, the proposed scheme is a efficiency group key agreement in IoT environment that guarantees secure communication among light-weight devices. The proposed scheme securely be able to communication with the group devices who share a group key, generated by own secret value and the public value. Such property is suitable to the environment which are required a local area and a group.

• Journal of Engineering Education Research
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• v.20 no.1
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• pp.63-68
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• 2017

This research is as a case study of innovative engineering education system through idea factory of korea maritime and ocean university and deals with development of temperature-humidity control device (THCD) for fiber storage on composites in viewpoint of problem solving method. Fiber reinforced plastic (FRP) includes many variables on the composite manufacturing process. Above all, the interfacial adhesion between the fiber and the matrix acts as an important thing that decided mechanical property of the FRP, and also it is profoundly linked to external temperature and relative humidity. High void fraction leads to a result in interlaminar fracture. Therefore, in this research, to establish correlation between fiber reinforcement and fiber storage conditions of temperature and relative humidity we developed a THCD for fiber reinforcement. To evaluate performance of the THCD, glass fiber reinforced plastic (GFRP) is made under the extreme conditions each temperature $34^{\circ}C$, relative humidity 98 % and it can be said that there are the change of mechanical properties according to fiber storage conditions. As a result, the THCD showed sufficient possible application for understanding and applied research of composites field in material engineering. Also, we could check that the necessity of introduction of innovative system such as idea factory existed.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.3
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• pp.1-10
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• 2018

Social network services allow you to share your thoughts and preferences more easily. They share your views with a large number of people who are friends with you without restriction of time or place. In the IoT environment, the amount of data is massively increasing as social network services spread rapidly. This change in the environment is driving the need for research into new retrieval methods that are different from conventional retrieval methods. In this paper, we propose a progressive retrieval method using the intimacy of social network users in the IoT. The first thing is to extract the user with the highest intimacy by using the property that the number of the owner of the information stored in the IoT environment is small. By accessing information in objects owned by these extracted users, the amount of information retrieved is reduced. It also improves retrieval efficiency by gradually retrieving information according to the user's level of interest. We present a new retrieval method and algorithm. The scenario also illustrates the effectiveness of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.7
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• pp.73-81
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• 1992

We have investigated the thermal reaction property and the oxygen behavior of TiN/Ti/Si structure after different hear treatments using x-ray photoelectron spectroscopy and cross-sectional transmission electron microscopy measurements. During the heat treatment in N$_2$ amibient, the considerable amount of oxygen atoms incorporates into TiN/Ti/Si Structures. It is found that oxygen atoms pile up at the top surface of TiN and TiN/Ti interface, forming a compound of TiO$_2$ above $600^{\circ}C$. Inside the TiN film, the oxygen content increases as the annealing temperature increases, mostly TiO and Ti$_2$O$_3$ rather than thermodynamically stable TiO$_2$. Above the annealing temperature of 55$0^{\circ}C$, the TiSi$_2$ formation has initiated. One thing to note is that a severe blistering is observed in the sample annealed at $600^{\circ}C$, due to (1) the difference of thermal expansion coefficient between TiN and Si` (2) the compressive stress induced by the volume reduction caused by the Ti-Silicide grain while elevating temperatures.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2005.05a
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• pp.93-97
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• 2005

People can't be free from the panic of flood, war and terrorism which could be fatal for people's life and property in modern society. It is the most important thing that provide food and residence for suffers in disaster areas. When disaster occurred, the emergency public facilities would be the first place that the people stay. However, these also could be destroyed by disaster. In that case, emergency tents or containers could be the major residence for disaster suffers. Because the only concern for planning temporary residence is the matter of supply and efficiency, it is no longer useful after the disaster end. Therefore, temporary residence as well as general residence should be on the basis of social and cultural factors as well as basic and physiological factors. It is very crucial to study the model of temporary residence. It could be the fundamental and necessary for the human being in order to prepare the natural disaster and grand scale accident. The main purpose for this study is examining the temporary residence that satisfy the fundamental, social and cultural factors for disaster sufferers.

• Korean Institute of Interior Design Journal
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• v.19 no.1
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• pp.137-147
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• 2010

The purpose of this study is to research a method of creating a new type of boundary by repeated disposition of single unit of modularized membrane successively. In the contemporary architectural indoor space, more highly dimensional analysis of boundary is required and the necessity of establishing boundary of a new concept that may satisfy cultural value, social value and artistic value as a whole as well as aesthetic and functional merit has been increased. In order to create a membrane that may fulfil the requirements of the diversified programs of space like this, an approach of complicated mechanism and high-dimensional calculation are required. At this time, digital GA modelling, parametric modelling technique may expand its range of possibility. One thing to be noted at this juncture is that indefinite expandability involved in digital modelling technique, modelling by grid of absolute and relative coordinates and convenience of systematization may surpass limitation of analogue or simple numerical calculation being progressed in the past. And in order to create solid process including unit modelling or pattern formation, Precise calculation process of computer is necessitated inevitably.

• Journal of Welding and Joining
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• v.16 no.3
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• pp.157-166
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• 1998

Recently as environmental pollution caused by Pb has posed a serious threat to the global environment, the trend to regulate the usage of Pb in electronic industry is one the rise. Currently, the solder alloy with high Pb content, Sn-37%Pb, is utilized in the electronic assembly therefore, the objective of this study is to develop an alternative solder alloy for the existing Sn-37%Pb solder alloy. First thing, this work choosed Sn-5%Pb-1.5%Ag, Sn-5%Pb-1.5%Ag-x%Bi(x=1~5%) for candidate solder alloys, and examined their properties such as melting range, wettability, microhardness, tensile property, oxidation behavior and microstructure. Wettability was on the same level of Sn-37%Pb. Dissolution of Pb ion in Sn-5%Pb solder was 0.46ppm. This solder alloy revealed cellular dendrite microstructure $\beta$-Sn matrix, Pb-rich phase, Ag/Sn, and Cu/Sn Intermetallic compounds. The range of solidification temperature was within 3$0^{\circ}C$. Also these alloy displayed higher tensile strength and lower elongation than Sn-37%Pb. The resistance of oxidation in Sn-5%Pb-1.5%Ag solder alloy was superior to that of Sn-37%Pb solder alloy. But that of Sn-5%Pb-1.5%Ag-5%Bi solder alloy was equal to that of Sn-37%Pb solder alloy.