• Korean Journal of Optics and Photonics
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• 제12권3호
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• pp.240-249
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• 2001

A high speed ultra-compact lens with a diffractive optical element (DOE) is designed, which can be applied to mobile communication devices such as IMT2000, PDA, notebook computer, etc. The designed hybrid lens has sufficiently high performance of less than f/2.2, compact size of 3.3 mm (1st surf. to image), and wide field angle of more than 30 deg. compared with the specifications of a single lens. By proper choice of the aspheric and DOE surface which has very large negative dispersion, we can correct chromatic and high order aberrations through the optimization technique. From Seidel third order aberration theory and Sweatt modeling, the initial data and surface configurations, that is, the combination condition of the DOE and the aspherical surface are obtained. However, due to the consideration of diffraction efficiency of a DOE, we can choose only four cases as the optimization input, and present the best solution after evaluating and comparing those four cases. On the other hand, we also report dramatic improvement in optical performance by inserting another refractive lens (so-called, field flattener), that keeps the refractive power of an original DOE lens and makes the petzval sum zero in the original DOE lens system. ystem.

• Journal of the Korean Geotechnical Society
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• 제30권6호
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• pp.5-21
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• 2014

It has been pointed out that the collapses of unsaturated road embankments caused by earthquake are attributed to high water content caused by the seepage of the underground water and/or the rainfall infiltration. Hence, it is important to study influences of water content on the dynamic stability and deformation mode of unsaturated road embankments for development of a proper design scheme including an effective reinforcement to prevent severe damage. This study demonstrates dynamic centrifugal model tests with different water contents to investigate the effect of water content on deformation and failure behaviors of unsaturated road embankments. Based on the measurement of displacement, the pore water pressure and the acceleration during dynamic loading, dynamic behavior of the unsaturated road embankments with about optimum water content and the higher water content than the optimum one have been examined. In addition, an image analysis has revealed the displacement field and the distributions of strains in the road embankment, by which deformation mode of the road embankment with higher water content has been clarified. It has been confirmed that in the case of higher water content the settlement of the crown is large mainly owing to the volume compression underneath the crown, while the small confining pressure at the toe and near the slope surface induces large shear deformation with volume expansion.

• Journal of the Korean earth science society
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• 제39권3호
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• pp.275-290
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• 2018

This study is to investigate how science and engineering integrated (SEI) lessons affect science-gifted students' perceptions about engineers and engineering practices. Twenty elementary science gifted students participate in this study, and they reflect what engineering practice means such as managing limited time and budget. The SEI lessons with 24 hours class time are used as an intervention. The main data are collected with 'engineer and engineering drawing test', open-ended questions and interviews about the drawing, and focus group interviews about the lessons. The transcribed interview data are analyzed using mixed methodology of quantitative (descriptive and paired t-test) and qualitative methods. The result shows that the SEI lessons have positive impacts on the science-gifted students' perceptions about engineers and engineering practices such as engineering design. After the lessons, the students perceive engineering and engineers in a desired way such as engineering as a social practice that many experts work collaboratively, the interaction between engineering and society, and the importance of ethics and social values in engineering practice.

• Culinary science and hospitality research
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• 제15권3호
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• pp.197-212
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• 2009

Well-set tabletops influence customers' purchase behavior or post-purchase behavior by making the quality and image of a restaurant distinguished and customers impressed. This study aims to investigate the relations between the perception of environment among physical environments of restaurants and psychological responses to their tabletops and consumers' attitudes in order to suggest new guidelines for table-setting. As a result, the direct relations between the perception of environment in the tabletops of the restaurants and consumers' behavioral intention indicated that the perception factors of tabletops affected consumer behavior and that these perception factors affected the formation of general attitudes among consumers through emotional and cognitive responses. This result shows that tabletops can be an important key in managing restaurants with changing customer needs. Therefore, it is expected that positive customer attitude can be made by provoking their psychological responses with unique and attractive tabletop settings.

• Journal of the Korea Institute of Building Construction
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• 제13권6호
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• pp.530-540
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• 2013

The business environment that affects the management performance can be characterized by each Strategic Business Unit (SBU) since construction companies win overseas contracts due to the fairly good construction situations while experience a decline in the local housing market. Environmental changes can alter the strategic importance of the SBU when measuring the management performance. However, large construction companies apply BSC (Balanced Score Card) for collective calculation to determine the management performance, making it difficult to reflect the strategic importance of SBU. This method may create a distorted image of management performance that fails to take environmental changes into consideration, and as such it needs to be improved. Yet, there are no studies on the weight of each SBU considering environmental changes. Thus, the current study intends to analyze the weight of SBU for company-wide measurement of the performance of large construction companies. In addition, a model for analysis of SBU importance is proposed to respond to the constantly changing environmental situations and to modify the weight. For analysis of SBU weight, a questionnaire was conducted with 23 experts and hands-on workers, and the questionnaire result was quantitatively analyzed by applying the FD-AHP method. It is expected that the result will enable a model to be proposed to calculate the weight per division in a manner that reflects environmental changes and minimizes strategic distortion when measuring the management performance of large construction companies.

• Journal of the Korean Institute of Intelligent Systems
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• 제15권6호
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• pp.714-719
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• 2005

The paper attempts to design and implement the system which can remotely check visitors' speech or Image by a mobile phone. This system is designed to recognize who a visitor is through the automatic calling service, not through a short message, via the mobile phone, even when the home owner is outside. In general, door locks are controlled through the home Server, but it is more effective to control door locks by using DTMF signal from a real-time point of view. The technology suggested in this paper makes it possible to communicate between the visiter and the home owner by making a phone call to tile home owner's mobile phone automatically when the visiter visits the house even if the home owner is outside, and if necessary, it allows for the home owner to control the door lock remotely. Thanks to the system, the home owner is not restricted by time or space for checking the visitor's identification and controlling the door lock. In addition, the security system is improved by changing from the existing password form to the combination of password and speaker verification lot the verification procedure required for controlling the door lock and setting the environment under consideration of any disadvantages which may occur when the mobile Phone is lost. Also, any existing problems such as reconnection to tile network for controlling tile door lock are solved by controlling the door lock in real time by use of DTMF signal while on the phone.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제19권6호
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• pp.175-181
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• 2019

For the purpose of Application to the small radar sensor, the MMIC Chip, which is the core component of the W-band, was designed in Korea according to the characteristics of the transceiver and manufactured by 0.1㎛ GaAs pHEMT process, and compared with the MMIC chip purchased overseas. The noise figure of low noise amplifier, insertion loss of the switch and image rejection performance of the down-converted mixer MMIC chip showed better characteristics than those of commercial chips. The MMIC chip developed in domestic was applied to the transmitter and receiver through W-band waveguide low loss transition structure design and impedance matching to verify the performance after the fabrication is 9.17 dB, which is close to the analysis result. As a result, it is judged that the transceiver can be applied to the small radar sensor better than the MMIC chip purchased overseas.

• Journal of the Institute of Electronics and Information Engineers
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• 제51권3호
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• pp.164-173
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• 2014

In underwater robotics, vision would be a key element for recognition in underwater environments. However, due to turbidity an underwater optical camera is rarely available. An underwater imaging sonar, as an alternative, delivers low quality sonar images which are not stable and accurate enough to find out natural objects by image processing. For this, artificial landmarks based on the characteristics of ultrasonic waves and their recognition method by a shape matrix transformation were proposed and were proven in Part 1. But, this is not working properly in undulating and dynamically noisy sea-bottom. To solve this, we propose a framework providing a selection phase of likelihood candidates, a selection phase for final candidates, recognition phase and tracking phase in sequence images, where a particle filter based selection mechanism to eliminate fake candidates and a mean shift based tracking algorithm are also proposed. All 4 steps are running in parallel and real-time processing. The proposed framework is flexible to add and to modify internal algorithms. A pool test and sea trial are carried out to prove the performance, and detail analysis of experimental results are done. Information is obtained from tracking phase such as relative distance, bearing will be expected to be used for control and navigation of underwater robots.

• International Journal of Costume and Fashion
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• 제7권1호
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• pp.49-61
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• 2007

The subject of study concerns the color characteristics of clothing/accessories from �Chosun�a nd modern Korea. It particularly focuses on the colors of the �Jeogori? traditional jacket) which represents Korean traditional clothing. Color data were collected from 353 woman�s �Jegori�s from �Chosun�a nd modern Korea and divided into the predominant colors & sub colors, and analyzed with HV/C and PCCS. According to the analysis, the representative the predominant color of 'Chosun Jeogori' for woman is YR, Y and side one is R, YR. The p, dp, sf, ltg colors are frequently found and the freshness of most of them is medium or low which shows a calm-feeling. The p, and ltg tones are often found as a the predominant color and p, dp are also often found as a the side color. In the 'Chosun Jeogori' for woman, the predominant colors and the side colors spread in a similar frequency and most of them have medium or low freshness of the color that shows a calm-feeling. The side color is one of the R colors and it shows characteristics of traditional coloring such as �Jajoo Goreum? Among the �Jeogori�f or modern women, the R, YR, Y, and B colors are often used for the single-color �Jeogori? the Y, GY, N, G colors are for the colorful �Jeogori? The P, lt, and b tons of the color are often used for a single-color �Jeogori�a nd the p, lt, and W are for the colorful �Jeogori? For the colorful �Jeogori? the side color have a high freshness which shows that a strong image was used frequently as the dp, s, dk tons of the color were often used. According to an analysis of the coloring, the predominant color and the side color of �Chosun Jeogori�a re applied to create a harmony of analogy & contrast in one aspect of Moon & Spencer�s view. It is found that the predominant color and the side color are similar or contrasting in one view of the color harmony, except that the traditional the �Jeogori�i s colored by ideological and symbolic meanings. The predominant color and the side color of modern the �Jeogori�a re complementary colors which are applied to the indistinct relationship or contrasting harmony in one aspect of Moon & Spencer�s view of the color harmony. The characteristics of the color as above show that traditional the �Jeogori�r egards the side color as both the harmony of the colors in general and also of symbolic meaning, while modern the �Jeogori�f or woman has a tendency toward a cultural transition and is mixed with new colors focusing more on its the predominant color than on the general harmony and character of ideological & traditional coloring.

• Toxicological Research
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• 제11권2호
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• pp.315-327
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• 1995

Diverse neurotoxic insults result in proliferation and hypertrophy of astrocytes, a subtype of glia in central nervous system. The hallmark of this response, often terms "reactive gliosis", is the enhanced expression of the major intermediate filament protein of castrocytes, glial fibrillary acidic protein (GFAP). These changes in the astrocytes suggest that GFAP may be a useful biochemical indicator of neurotoxicity. To investigate this possibility, we administered intra-peritoneally prototype nerotoxicants, metharnphetamine (MAP, 5 mg/kg), cocaine (30 mg/kg), N-buthyl benzenesulfonamide (NBBS, 300 mg/kg) and trimethytin (TMT, 8 mg/kg) to Wistar Rats and then assessed the effects of these agents on content of GFAP, which were determined by Sandwish ELISA and evaluated with neurotoxic symptoms, and quantitative changes of imrnunoreactivity of GFAP by light microscopic image analysis in specific regions. We found that assay of GFAP revealed time- and region-dependant patterns of neurotoxicity. The GFAP immunoreactivity of rat brain was increased in substantia nigra and hippocampus by MAP, NBBS and TMT; in roedial septal nucleus and nucleus accurnbens, it was also increased by RrBBS. Sandwich ELISA showed that GFAP levels of cerebrum in all groups on days 3 and 7 and that of brainstem(including cerebellum) in MAP, NBBS groups on day 1 and 3 were increased. A review of the background, design and results of these experiments are presented in this paper. Our findings indicate that GFAP is a sensitive and specific biomarker of neurotoxicity.otoxicity.