• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1070-1076
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• 2007

In this paper, we study the characteristics of dual band microstrip antenna with the wedge-shaped radiation patch added the slot using air substrate. Wedge-shaped patch antenna with air substrate is avoided the large probe reactance associated with a thick substrate owing to the use of short probe and good impedance matching over a wide frequency range can be obtained. Slot on the antenna radiator varies the reactance component according to the employed frequency and affect the resonance freaqency of the antenna, therefore the antenna can resonate at the dual band(cellular and PCS band). The slot length and position have an effect on the bandwidth and input impedance of the antenna are optimized by simulation. From the experiment results for the fabricated antenna, -10 dB of $S_{11}$ is content with the allocated bandwidth of Cellular and PCS system and - 15 dB of cross polarization level. From the results of this paper, it has been confirmed that the proposed antenna can be used as the base station antenna fur Cellular and PCS band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.9
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• pp.1718-1724
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• 2017

Recently, Smart plugs for real time monitoring of household appliances based on IoT(Internet of Things) have been activated. Through this, consumers are able to save energy by monitoring real-time energy consumption at all times, and reduce power consumption through alarm function based on consumer setting. In this paper, we measure the alternating current from a wall power outlet for real-time monitoring. At this time, the current pattern for each household appliance was classified and it was experimented with deep learning to determine which product works. As a result, we used a cross validation method and a bootstrap verification method in order to the classification performance according to the type of appliances. Also, it is confirmed that the cost function and the learning success rate are the same as the train data and test data.

• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.1-11
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• 2017

In this study, novel approximate form of the square-root operator of three dimensional acoustic Parabolic Equation (3D PE) is proposed using a rational approximant for two variables. This form has two advantages in comparison with existing approximation studies of the square-root operator. One is the wide-angle capability. The proposed form has wider angle accuracy to the inclination angle of ${\pm}62^{\circ}$ from the range axis of 3D PE at the bearing angle of $45^{\circ}$, which is approximately three times the angle limit of the existing 3D PE algorithm. Another is that the denominator of our approximate form can be expressed into the product of one-dimensional operators for depth and cross-range. Such a splitting form is very preferable in the numerical analysis in that the 3D PE can be easily transformed into the tridiagonal matrix equation. To confirm the capability of the proposed approximate form, comparative study of other approximation methods is conducted based on the phase error analysis, and the proposed method shows best performance.

• Korean Journal of Optics and Photonics
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• v.25 no.5
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• pp.254-261
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• 2014

Two types of white light-emitting diodes (LEDs) with different phosphor structures were fabricated and compared in terms of their optical characteristics. Their spectroscopic properties were analyzed as a function of temperature, from room temperature to $80^{\circ}C$. The temperature dependence of the luminance and the color coordinates showed that the decrease in luminance and change in the color coordinates of the remote-phosphor type LED were much smaller compared to the conventional white LED. These improvements were attributed to the decrease in phosphor temperature, due to the distance between the LED chip and the phosphor layer, as well as to the reduced absorption by the LED chip of the light emitted from the phosphor layer.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.244-256
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• 2009

The psoralen-pyrimidine base complexes resulting from interstrand cross-linking through $C_4$-cycloaddition is studied by ab initio and DFT methods. The results indicate that in the case of the molecular complex formation between psoralens and pyrimidine base, the most probable photocycloadditions are 8-MOP< >Thy, Ps< >Cyt and Ps< >Thy. The geometries of photoadducts were optimized at the HF levels and ${\Delta}{G^{\circ}}$ were calculated. The photocycloadduct was inferred to be a C4-cycloaddition product with the stereochemistry of trans-syn 8-MOP< >Thy, trans-anti Ps(3, 4)< >Cyt, trans-anti Ps(12, 13)< >Cyt, trans-syn Ps(3, 4)< >Thy, trans-syn Ps(12, 13)< >Thy, trans-anti Ps(12, 13)< >Ps(12, 13), cis syn, cis anti Thy< >(3, 4)Ps(12, 13)< >Thy.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.999-1004
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• 2007

Spherical porous silica supports modified with titanium or zirconium alkoxides were prepared, and allyl groups were chemically attached to the titanized or zirconized silica supports, and the product was cross-polymerized with a double bond containing cellulose derivative to yield new CSPs (chiral stationary phases). Magic angle spinning 13C solid state NMR and elemental analysis were used to characterize the CSPs. The performances of the chiral stationary phases were examined in comparison with a conventional chiral stationary phase. Spherical porous silica particles modified with 3,5-dimethylphenylcarbamate of cellulose were prepared and used as the conventional chiral stationary phase. Chromatographic data were collected for a few pairs of enantionmers in heptane/2-propanol mixed solvents of various compositions with the three chiral columns and the results were comparatively studied. The separation performance of the chrial phase made of the titanized silica was better than the others, and the separation performance of the chiral phase of the zirconized silica was comparable to that of the conventional chiral phase. The superiority of titanized silica over bare or zirconized silica in chiral separation seemed to be owing to the better yield of crosslinking (monitored by increase of carbon load) for titanized silica than for the others.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.225-230
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• 2000

The texture profile analysis (TPA) parameters of commercial surimi-based products were evaluated at various compression test conditions. Cylindrical specimens of diameter to length (D/L) ratio of 1.0, 1.5, B.() cm/min were compressed to 50, 65 and 80% using crosshead speeds of 1.7, 3.3, 6.7 cm/min. TPA parameters of three surimi-based products (hardness-1, hardness-2, cohesiveness, springiness, chewiness and gumminess) were analyzed statistically. The TPA parameters were modified by dividing with cross section area and strain. The TPA parameters were affected by D/L and compression ratio except for crosshead speed for all three surimi-based products. The ecommended test conditions for TPA of surimi-based products seem to be D/L of 1.5, compression ratio of 80%, and crosshead speed of 1.7 to 6.7 cm/min.

• Journal of Fashion Business
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• v.18 no.5
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• pp.159-170
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• 2014

Recent concerns about the PFOA(perfluorooctanoic acid), have been increasing, which is generally applied in the water-repellent finishing process of textile products. It has been proven through animal testing to be harmful to humans, as possible carcinogens and neuro-toxic material. Thus U. S. Environmental Agency has gone as far as requiring the material to be eliminated in its entirety by 2015. As a viable alternative to this water-repellent finishing agent, the development of C6 product is gaining its popularity. The effects of PFOA finishing on the silk fabrics were examined, and we reviewed parameters of the needed process for optimizing appearance and functionality of silk fabrics treated with eco-friendly water-repellent finishing agent. Cross-linking agent affected the most on black color of reactive ink, among the physical properties. The contact angle reading was the highest in $8g/{\ell}$ of concentration for all fabrics. All the fabric specimens, subjected to the DTP and water repellent finishing, exhibited higher stiffness, where rayon specimen showed the highest, compared to the untreated specimens. The results may provide basic information leading to the development of value-added silk fabrics with water-repellency without excessive deterioration of the delicate appearance and inherent soft touch.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.6
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• pp.902-912
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• 2010

This study compares and contrasts the consumer decision-making styles (CDMS) of South Korean and American Generation Y females. A total of 117 American female and 206 Korean female consumers completed self-report survey questionnaires to assess their consumer decision making styles. Exploratory principal components factor analysis using varimax rotation was used to categorize the items into an underlying set of American and Korean decision-making characteristics. Two-tailed independent t-tests were conducted to examine the differences between the two groups when items appeared to have common factors. Factor analysis identified five common factors between the two samples (i.e., enjoyment, shopping aversion, price consciousness, brand consciousness, and quality consciousness). The t-test results report significant differences in the items reported in each factor between American and Korean females. Some of the factors are more indicative of American female Generation Y consumers than Korean female Generation Y consumers. For example, the American female sample seemed to enjoy shopping and prefer brand names more than the female Korean sample. Koreans females seem to have a higher aversion to shopping than Americans; in addition, Koreans females seem to be more accepting of discount and outlet stores, will wait until the price is low before buying a product, and prefer sales when shopping. Based on the findings, the instrument identified varying CDMS between the two samples used. Previous studies using the Sproles and Kendall (1986) instrument experienced the same issue (Bakewell & Mitchell, 2004, 2006; Bauer et al., 2006; Durvasula et al., 1996; Fan & Xiao, 1998; Hanzaee & Aghasibeig, 2008; Mitchell & Walsh, 2004; Siu et al., 2001; Walsh et al., 2001). The results support the idea that no single instrument can be used to examine CDMS in different cultures. This suggests that each country has a CDMS with internal characteristics. Limitations and research for future studies are also discusse.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.681-687
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• 2013

Free Trade Agreement(FTA) aims at abolishing tariffs on trade among nations or regions resulting in having a significant impact on maritime transportation and port. Korea made the first FTA with Chile in 2004 and the trade volume between two countries has seen significant increase. The literature on such impact, however, seems to be very limited. The main purpose of this study is, therefore, to analyze the impact of Korea-Chile Free Trade Agreement on the imported container throughput from Chile at the Busan Port. For this both cross-sectional and time series data are collected that comprise container throughput, Gross Domestic Product (GDP), import tariff, and maritime freight rate, from 2000 to 2011, and the gravity model is applied. The main result of the study shows that the dependent variables, GDP and import tariff are statistically significant, but the maritime freight rate is not consistent with regarding to statistical significance and parameter sign.