• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.2
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• pp.107-111
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• 2003

In the power-line communication systems, there are many factors of noise and attenuation in the power-line channels, because they were designed for not the communication but the power transmission. Also the transfer function of the channels is highly changed with the topology and the load of the power-lines. To cope with these poor channel situation, channel modeling, one of the many studies in progress, is being studied hard. Channel modeling is essential to apply the active schemes to overcome the bad channel(e.g. modulation technique, channel coding, signal coupling & filtering, etc.) to the power-line communications. In this paper, we have realized the statistical model(this model is suggested as the channel modeling method for the power-line channels) that is combined the transfer function with the various noises. And we have compared and examined the results with the measured data. Also we have studied the plan which can effectively establish the channel data base for the channel information consisted of the parameters that are derived from this modeling, and we have studied the plan to utilize the data base.

• Journal of Power Electronics
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• v.14 no.3
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• pp.564-571
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• 2014

Rotor initial position is an important factor affecting the control performance of electrically excited synchronous motors. This study presents a novel method for estimating rotor initial position based on sliding discrete Fourier transform (sDFT). By injecting an ac excitation into the rotor winding, an induced voltage is generated in stator windings. Through this voltage, the stator flux can be obtained using a pure integral voltage model. Considering the influence from a dc bias and an integral initial value, we adopt the sDFT to extract the fundamental flux component. A quadrant identification model is designed to realize the accurate estimation of the rotor initial position. The sDFT and high-pass filter, DFT, are compared in detail, and the contrast between dc excitation and ac injection is determined. Simulation and experimental results verify that this type of novel method can eliminate the influence of dc bias and other adverse factors, as well as provide a basis for the control of motor drives.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.210-213
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• 2002

For insulation design of the superconducting transformer, many types of insulation tests should be carried out. To clarify the components of insulation for superconducting transformer, there are main four parts as 1ike that turn-to-turn interior of each primary and secondary windings, layer-to-layer between primary and secondary windings, and winding to grounded structures. The insulation components should meet the required withstand voltage of the system and enough safety factors must included. As the fundamental insulation characteristics, we tested surface flashover voltage of spacer that would place between the coils and would take the role of both cooling duct and insulator. The structure of spacer in practice vary depending on coil type, in this work we considered double pancake coil for the superconducting transformer. In this study we tested flashover voltages of several arrangement of spacer.

• Environmental Engineering Research
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• v.15 no.1
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• pp.49-56
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• 2010

Based on a survey of citizens and data analysis on the environmental status of the Miyun Reservoir watershed, China, the environmental awareness of citizens residing in the watershed and the impacting factors are discussed. The contingent valuation method was used to evaluate the willingness of villagers to pay (WTP) for abatement of the rural domestic pollution and to assess the intensity level of the villagers' desire for improving environmental conditions in the Miyun Reservoir watershed. It was found that rural watershed residents had a fundamental cognitive understanding of the pollution status and protection measures of the Miyun Reservoir. However, based on the survey, local residents had only a small interest in their participation to improve the environmental status of the reservoir, despite their general attitude to protect the reservoir being very positive. Gender and family income were closely associated with the overall attitudes of the population. Public media are the most preferable means for conveying knowledge of environmental protection to people living in the watershed. Increasing the educational level, along with income, are the best ways to enhance the desire of the villagers to improve the environmental quality and management.

• Korean Institute of Interior Design Journal
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• no.37
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• pp.88-94
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• 2003

In recent years, the direction of the contemporary design paradigm has been shifting from the western to eastern culture; while the western paradigm focuses more on logic and reasons, the eastern paradigm values more on the emotional factors. Today, the interior architecture, in the professional field of design, is gaining its attention from the public due to its rapid development of multi-purpose intelligent buildings which are expected to grow more in coming years. Users are becoming high in demand for the maximum efficiency 8f aesthetical Intoners. While functionality Is the fundamental element In office design, there are increasing request to express uniqueness in the given space such as including the traditional concepts specially when we are living in the era of "globalization". The effect of both WTO policy and the globalization, brought many multinational or foreign companies to expand in Korea. Their request for interior design is to reflect Korean traditions in the office space in order to present the regional characteristics of Korea. Office designs in Korea has been developing rapidly in terms of its advancement in building technology and visual aesthetics. However, the Korean traditional concepts have been expressed very broadly without any boundary or knowledge. Thus, the objective of this study is to analyze the Korean traditions and design elements expressed in various office spaces on case-by-case basis and to provide the typology and the guidelines for the future designs.e designs.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.69-76
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• 2009

As sensibility ergonomics are broadly spread, recently in interior design area, interests on roles of sensibility, sensibility effects for users, and etc has been increased. As a study on sensibility design for interior design area, the study applied sensibility ergonomics technique to bathroom interior design. Sensibility ergonomics technique is integrated into each phase of bathroom design process in order to produce 4 design alternatives. Sensibility evaluation on design alternatives was performed for subject of designers, and analyzed the results to show the relationship between sensibility of designers and design factors and to identify characteristics of designer's sensibility structure. The results of the study are as follows. First, it's found that in the bathroom interior design of sustainable concept, uses of bright colors with white tone and floor tile creates positive sensibility responses such as delight, healthiness, spaciousness, and cheerfulness. Second, designers' sensibility structure about sustainable bathroom is composed of three axles, healthiness, eco-friendliness, and refinement. Third, designers think colors of interior and finished materials is most important, and window, artificial lighting, layout, and space size related to those is important too. The process and approach in the study might contribute to building a fundamental of sensibility design research in interior design area.

• Nuclear Engineering and Technology
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• v.25 no.4
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• pp.570-587
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• 1993

Recently a number of severe fuel degradation events, seemingly due to internal secondary hydriding, have been reported. This paper reviews internal hydriding of defected zircaloy cladding. First, the history of zircaloy cladding development and the environment of the zircaloys in service in the nuclear reactor are introduced. Fundamental aspects of zircaloy hydriding, such as hydrogen permeability in zirconium oxide, terminal solubility and precipitation in zirconium and its alloys, and the deleterious effect of hydrides are reviewed. The mechanism of massive internal hydriding in defected zircaloy fuel rods is qualitatively described based on the observed phenomena. Significant factors affecting the hydriding process are discussed. A quantitative model for the massive hydriding as a part of an effort to mitigate fuel degradation is briefly mentioned and necessary information and recommended future work for improvement of the model are outlined.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.5
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• pp.37-44
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• 2001

Fracture toughness was considered as one of the good estimates of the paper break tendency of paper web in the press room. Paper break on the paper machine is caused by many factors such as paper machine irregular vibrations, impurities in the fiber furnish, shives, and so on. On the paper machine, the solid content of paper web is changing very rapidly from less than 1% to over 95%. We tried to measure the fracture toughness of paper web at different solid contents for providing the fundamental knowledge of paper break. Stretches of wet web were also measured and compared to the fracture toughness changes. Four different fiber furnishes (SwBKP, HwBKP, ONP, and OCC) were refined to different degrees, and at different solid contents (40%, 60%, 80% and 95%), their fracture toughnesses were measured. Two fracture toughness measurement methods (essential work of fracture and Tryding's load-widening method) were used, and we found they gave identical results. The stretch curves of the wet webs against the axis of solid contents were very similar to the fracture toughness curves of those.

• Journal of fish pathology
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• v.23 no.3
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• pp.379-388
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• 2010

This paper presents a computer program for easy and rapid disease diagnosis of olive flounder diseases. To design the program, standard diagnosis process of the 14 olive flounder diseases was first setup, then implemented four-steps diagnosis program. To run program, first input fundamental information such as water temperature, size of the diseased fish. Then sequentially, three categories of key factors for disease diagnosis which include external clinical signs, internal clinical signs and microscopic observations are selected. When a user selects the observed signs of olive flounder from the listed options, the program provides maximum 5 presumed disease candidates in order. The disease information, treatment and prevention methods are provided by connected web server through internet. The program would support fish doctors and farmers by providing easy and rapid diagnosis of diseased olive flounder.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.161-167
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• 1999

There is an increasing need for the estimation of foundation piles whose depths are unknown. Especially in repair and reinforcement works or in safety inspection and assessment to the big structures whose foundations are piles, the accurate information about the depth of foundation piles is one of the most important factors. A borehole magnetic tool has been developed and tested to meet this object. The fundamental base is that there usually exist many re-bars inside the foundation structure such as piles, and these re-bars are ferromagnetic materials which cause strong induced magnetic field comparable to the earth magnetic field. It utilizes flux-gate type magnetometer which measures 3-components of the magnetic field. Taking vertical derivatives of vertical component of the measured magnetic field, we can expect the error limit of estimating the depth of the pile end less than 20 cm in favorable condition. The maximum measurable distance is about 3 m to the pile from the borehole. The field data show that borehole magnetics is one of the most accurate, fast, and reliable methods for this object so far, as long as there is no magnetic materials such as deep located steel pipe or power cables close to the foundation piles.