• Journal of the Korean Data and Information Science Society
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• 제16권1호
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• pp.115-126
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• 2005

In this paper, we derive the approximate maximum likelihood estimators of the scale parameter and location parameter of the double exponential distribution based on Type-II censored samples. We compare the proposed estimators in the sense of the mean squared error for various censored samples.

• 한국생활과학회지
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• 제13권3호
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• pp.467-475
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• 2004

The purpose of this study was to examine the sewing construction of a double robe, the difference between the single and double robe, and the size and construction method of the double robe through a close analysis of a replica to facilitate a better understanding of the robe making in late Chosun dynasty. The results were as follows: 1. There was no significant difference in the design and sewing method between the girl's robe and an adult's even though the girl's robe was much smaller. 2. The girl's robe differed from its modern counterparts in some respects: unlike modem robes, Chungyun's robe consisted of two-layers in which the four layers were sewn together and it could be seen most clearly in the way the collar was stitched only onto the outer layer. The two layers seemed to be put on successively since they were not sewn together. The inner collars of the two robes were sewn together when the maker put on a coat string to the outer robe, and the two robes were put together with hemming and blind stitch at the top of the outer collars to make the robe formally stable, which clearly distinguished the princess' robe from a single, for example, four-layered robe. The robe was constructed using traditional sewing methods including broad stitch, back stitch, hemming, and blind stitch, and each stitch was only about 1 mm wide. 3. The maker of the robe managed to construct a formally stable and aesthetically satisfactory robe with the least amount of fabric and proper sewing methods.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.412-417
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• 2003

In recent years, efficient commuter transportation has become one of major issues to be taken into account around Seoul metropolitan area. In oder to solve the problems, several countries such as Japan, France and so on gradually operate double deck trains as efficient, reliable and comfortable mass transportation systems. However, the double deck trains have relatively big cross sectional areas and high mass centers that cause unsafe vehicle running performances and interface problems between the vehicles and infrastructures, and do not have enough spaces for electric equipments. Therefore, prior to operate double deck trains on the existing lines in Korea, careful investigations should be performed. For these reasons, we have studied the double deck train system for the existing lines around Seoul metropolitan area as an alternative way to carry heavy transportation efficiently and comfortably.

• 한류연구
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• 제2권1호
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• pp.1-8
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• 2023

The South Korean automotive industry has been the major producer for both domestic and international market. This rises of the South Korean automotive industry has resulted in combination various factors ranging from government policies and the foreign investment. The Double Helix model provides a comprehensive and useful framework to understand how these factors have interacted to shape the history of the auto industry of South Korea. This research aims to provide the history of the Auto Industry in Korea based on the Double Helix Model. To collect textual literature dataset, the present author tried to screen and select adequate prior studies in the past and current literature to achieve the purpose of the study. According to the literature analysis, the history of the automotive industry in South Korea is an interesting case in the successful implementation of the Double Helix model. The model emphasizes the collaboration between the government and the private sector in achieving common goals. This research founded the four historical events of the development of the South Korean automotive industry based on the Double Helix Models. In sum, the research concludes that the Double Helix Model is an essential tool for understanding the historical development of the auto industry in South Korea.

• 한국실내디자인학회논문집
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• 제24권4호
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• pp.91-98
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• 2015

Double skin façade is known that several features affected the building energy and daylighting performance. That is why the envelope is able to consist of all architectural materials such as glass, aluminum, wood and insulation for vision of residents and workers in buildings. Its specifications is very diverse according to the building designers and building owners. In recent times, visual environment became a major focus and resulted in the development of cutting edge engineering of diverse glazing systems and shading devices by growing interests of friendly environment. Thus this research has evaluated the fluctuations of interior lighting and atmospheric conditions based on double skin facade systems. Especially in terms of daylighting environment as dependent on solar variations, this research provides quantitative analysis of interior lighting conditions and how it affects the living conditions as well as improve the design of interior spaces.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.873-876
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• 2002

It has been reported that discrepancies exist in the case of double panels with an air layer when the measured sound transmission loss is compared with the calculated values. It has been known that the cause of this discrepancy is in major from the unavoidable dips associated with the double wall resonances. In this work, several correction methods to make up for such resonances are studied. In particular, the ‘boundary damping’concept is revisited and its effects are discussed by comparing with measured values. It is shown that the correction methods are necessary for the sound insulation analysis of double partitions with an air layer, in order to ascertain the quantitative correlation between measured and predicted values.

• Journal of Power Electronics
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• 제19권2호
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• pp.602-611
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• 2019

The major drawbacks of magnetic resonant coupled wireless power transfer (WPT) to the embedded sensors on spindles are transmission instability and low efficiency of the transmission. This paper proposes a novel double-loop coil design for wirelessly charging embedded sensors. Theoretical and finite-element analyses show that the proposed coil has good transmission performance. In addition, the power transmission capability of the double-loop coil can be improved by reducing the radius difference and width difference of the transmitter and receiver. It has been demonstrated by analysis and practical experiments that a magnetic resonant coupled WPT system using the double-loop coil can provide a stable and efficient power transmission to embedded sensors.

• 한국산업융합학회 논문집
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• 제23권5호
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• pp.757-763
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• 2020

City gas buried pipes are managed by corrosion protection to prevent corrosion. In the case of the press-in section, the double pipe and the main pipe may cause corrosion under the influence of stray current, which can shorten the life of the pipes. In addition, if the insulator is filled in the press-in section, the press-in section itself is a single structure, and can be directly affected by external impact, and when the surrounding ground subsidence occurs, the stress may be concentrated, resulting in serious consequences. In this study, a serration-type shock absorber in the form of a sliding support was proposed as a new buried double piping construction method using EPS. The serration-type shock absorber can contribute to the improvement of the integrity of the buried double piping, as it can utilize the gas piping's own ductility and stress distribution characteristics with proper anti-corrosion management and shock-absorbing material properties by preventing contact inside the buried double pipe. However, for application to ground piping, there remains a task to supplement the vulnerability against fire due to the characteristics of EPS materials.

• International Journal of Aeronautical and Space Sciences
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• 제17권3호
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• pp.332-340
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• 2016

A design optimization is performed for the double-bolted joint in cylindrical composite structures by using a simplified analytical method. This method uses failure criteria for the major failure modes of the bolted composite joint. For the double-bolted joint with a zigzag arrangement, it is necessary to consider an interaction effect between the bolt arrays. This paper proposes another failure mode which is determined by angle and distance between two bolts in different arrays and define a failure criterion for the failure mode. The optimal design for the double-bolted joint is carried out by considering the interactive net-tension failure mode. The genetic algorithm (GA) is adopted to determine the optimized parameters; bolt spacing, edge distance, and stacking sequence of the composite laminate. A purpose of the design optimization is to maximize the burst pressure of the cylindrical structures by ensuring structural integrity. Also, a progressive failure analysis (PFA) is performed to verify the results of the optimal design for the double-bolted joint. In PFA, Hashin 3D failure criterion is used to determine the ply that would fail. A stiffness reduction model is then used to reduce the stiffness of the failed ply for the corresponding failure mode.

• KIEAE Journal
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• 제7권5호
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• pp.87-92
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• 2007

As expansion of balconies at apartments has been legalized, the major function of the balconies as a thermal buffer zone is disappearing. This weakens the ability of window to insulate heat and multiplies surface condensation. Thus more and more residents require solutions to increasing surface condensation and aggravation in thermal comfort. This study intends to provide basic data by evaluating performance of triple layered Low-E windows, triple layered clear windows, double layered Low-E windows and double layered clear window used for expanded balconies and marketed within the country in terms of surface condensation and thermal environment through simulation. Results revealed that no surface condensation occurred at double layered Low-E windows and triple layered Low-E windows. Surface condensation took place at double layered clear windows and triple layered clear windows at a relative humidity of 60%. Thermal environment analysis suggested that double layered clear windows showed the most time falling into the range of comfort at $23^{\circ}C$. The figure were $22^{\circ}C$ for triple layered clear windows, $22^{\circ}C$ for double layered Low-E windows and $21^{\circ}C$ for triple layered Low-E windows.