• Ocean Science Journal
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• 제43권4호
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• pp.165-173
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• 2008

In this article, we describe a simple yet effective method for insertion of observational datasets in a mesoscale atmospheric model used in one-dimensional configuration through Nudging. To demonstrate the effectiveness of this technique, vertical profiles of meteorological parameters obtained from GLASS Sonde launches from a tiny island of Kaashidhoo in the Republic of Maldives are injected in a mesoscale atmospheric model - Advanced Regional Prediction System (ARPS), and model simulated parameters are compared with the available observational datasets. Analysis of one-time nudging in the model simulations over Kaashidhoo show that incorporation of this technique reasonably improves the model simulations within a time domain of +6 to +12 Hrs, while its impact on +18 Hrs simulations and beyond becomes literally null.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2378-2383
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• 2007

Direct Numerical Simulation was carried out to predict mass transfer in turbulent flow around a rotating stepped cylinder. This investigation is a follow-up study of Nesic et al. [Corrosion, Vol. 56, No. 10, pp. 1005 - 1014] The original motivation of this work stemmed from the efforts to design a simple device which can generate flows of high turbulence intensity at low cost for corrosion researchers. Two cases were considered; Sc=1 and 10 both at Re=335. Here, Sc and Re stand for Schmidt number and Reynolds number, respectively, based on the step height and the surface speed of the cylinder upstream the step. Main focus was placed on the correlation between turbulent fluctuation and concentration field. The spatio-temporal evolution of concentration field is discussed. The numerical results are qualitatively compared with those of the experiment conducted with the same flow configuration.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2833-2838
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• 2007

Recently, small hydropower attracts attention because of its clean, renewable and abundant energy resources to develop. However, suitable turbine type is not determined yet in the range of small hydropower and it is necessary to study for the effective turbine type. Moreover, relatively high manufacturing cost by the complex structure of the turbine is the highest barrier for developing the small hydropower turbine. Therefore, a cross-flow turbine is adopted because of its simple structure and high possibility of applying to small hydropower. The purpose of this study is to examine the optimum configuration of nozzle shape to further optimize the cross-flow hydraulic turbine structure and to improve the performance. The results show that pressure on the runner blade in Stage 1 and velocity at nozzle outlet have close relation to the turbine performance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.101-108
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• 2011

In this paper we present the specification development for the localization of interlockings which control routes within a HSR station yard. For the electronic interlockings in Korea introduced from France in the 1990s, it has a complicated hardware configuration and communication protocols in order to secure safety. Now 30 years later, in case of the application of the up-to-date IT technology, it is expected to achieve equal or greater safety and save maintenance costs. Additionally, we develop the specification so as to utilize the stable domestic electronic interlocking technology for general railways, beyond the simple maintenance for the performance maintenance of foreign devices, to high-speed railways. Therefore, we perform a study for the localization of the HSR electronic interlockings by comparing and analyzing interlocking logic units between conventional HSR and general railways.

• 조명전기설비학회논문지
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• 제26권2호
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• pp.51-60
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• 2012

An improved method for detecting fault distance in overhead transmission lines is described in this paper. Based on single-ended measurement, propagation theory of traveling waves together with the wavelet transform technique is used. In estimating fault location, a simple, but fundamental method using the time difference between the two consecutive peaks of transient signals is considered; however, a new method to enhance measurement sensitivity and its accuracy is sought. The algorithm is developed based on the lattice diagram for traveling waves. Representing both the ground mode and alpha mode of traveling waves, in a lattice diagram, several relationships to enhance recognition rate or estimation accuracy for fault location can be found. For various cases with fault types, fault locations, and fault inception angles, fault resistances are examined using the proposed algorithm on a typical transmission line configuration. As a result, it is shown that the proposed system can be used effectively to detect fault distance.

• Architectural research
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• 제13권4호
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• pp.19-30
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• 2011

This investigation, based on empirical research, examined the role of complexity and order in the aesthetic experience of architectural forms. The basic assumption of this study was that perception in architectural form is a process of interpreting a pattern in a reductive way. Thus, perceptual arousal is not determined by the absolute complexity of a configuration. Rather, the actual perceived complexity is a function of the organization of the system (order). In addition, complexity and order were defined and categorized into four variables according to their significant characteristics; simple order, complex order, random complexity, and lawful complexity. The series of experiments confirmed that there is a point on the psychological complexity dimension which is optimal. By demonstrating that consensual and individual aesthetic preference can be measured to have a unimodal function of relationship with complexity, the results of the experiments indicated that complexity and orderliness are effective design factors for enhancing aesthetics of a building facade. This investigation offered a conceptual framework that relates the physical (architectural form) and psychological factors (complexity and order) operating in the aesthetic experience of building facades.

• Journal of electromagnetic engineering and science
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• 제12권4호
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• pp.247-253
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• 2012

This study presents a new, simple method for improving the front-to-back (F/B) ratio of a microstrip patch antenna. The back radiation of the microstrip patch antenna is reduced by removing some metallic parts around the ground plane and placing a new soft-surface configuration, consisting of an array of stand-up split-ring resonators on a bare dielectric substrate near the two ground plane edges. Compared to the F/B ratio of a conventional microstrip patch antenna with a full ground plane of the same size, our proposed microstrip patch antenna experimentally achieves an improved F/B ratio of 9.6 dB.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권4호
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• pp.505-508
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• 2012

A permanent magnet flux switching (PMFS) machine has a simple rotor, whilst both magnets and coils are set in the stator, resulting in easy removal of heat due to both copper loss and eddy current loss in magnets. However, the volume of magnets used in PMFS machines is usually larger than in conventional PM machines, and leakage flux does exist at the non-airgap side. To make full use of the magnets and gain higher power density, a novel 3-dimensional (3D) field PMFS machine is developed. It combines merits of the tubular linear machine, external-rotor rotary machine and axial-flux rotary machine, hence, offers high power density and peak torque capability, as well as efficient utility of magnets owing to the unique configuration of triple airgap fields.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.895-898
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• 2004

We propose configurations for a transflective in-plane switching (IPS) cell using muti-domain structures. Usually, the cell configurations for a transflective liquid crystal(LC) cell have a complicated structure, because retardation change of transmissive part and reflective part are not same. The transflective LC cell should have two configurations for each part, such as a multi-cell gap structure. With the ion-beam alignment and the horizontal switching LC cell, a simple structure for a transflective LC cell is proposed. The configuration only adopts one cell gap structure, which may help the enhancement of a yield. Their original optical properties in conventional transmissive and reflective type IPS liquid crystal dispaly(LCD) are kept, it shows the wide-viewing angle and the good wavelength dispersion characteristics.

• 한국실내디자인학회논문집
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• 제19권2호
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• pp.33-41
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• 2010

This study aims to analyze the typological characteristics of Alvar Aalto's library design. The unique characteristics of Aalto's architecture are the result of accommodating Modern architecture with regional qualities of Finland. Besides this, Aalto's typological approach in design made his color. The library might be the best example for understanding his design approach in that he showed 3 main features of type; wholeness, self-control and transformation. He established architectural types in his 30s through Viipuri public library and developed so-called fan type library plan. Aalto's library type is not a simple copy of exterior and interior form. It acts as a principle of configuration of his library architecture and applied to the building. Therefore, Aalto's library architecture can be recognized as the results of typological design approach in that it shows the transformation of type in according to factors including site, size, region and cultural tradition. In conclusion, Aalto's libraries reveal the typological characteristics in the field of building layout, dynamic space and the effective use of light.