• Elastomers and Composites
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• 제52권4호
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• pp.295-302
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• 2017

Polyurethane dispersion (PUD) polymers were synthesized by using polyether and polyester polyol. The effect of ionomeric centers, r(NCO / OH) values, chain extender process, and chain extender types on the adhesion properties was investigated. In the case of polyether-based PUD, the ionic center, r value, chain extension process and chain extender types were not adjusted even after adjustment. In the case of polyester-based PUD, when the ionic center content was more than 2.5%, the state of adhesive strength was $2.0kgf/cm^2$ or more. On the other hand, the initial adhesive strength was excellent at about $1kgf/cm^2$ when the ionic center content was over 3.5%. When the r value was 1.3 or more, it was found that the initial bonding strength and the state of bonding strength were excellent at about $1kgf/cm^2$ and $2.1kgf/cm^2$ or higher, respectively. An IR spectrum analysis of the synthesized PUD confirmed that PUD was composed of urethane based on the N-H characteristic peak at $3340cm^{-1}$ and the urethane characteristic peak at $1730cm^{-1}$. Moreover, the characteristic peaks of the isocyanate ($2260cm^{-1}$) used in the preparation of the prepolymer were not observed. As a result, the residual -NCO was not observed, and urethane was completely synthesized.

• 한국의류학회지
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• 제31권5호
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• pp.777-787
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• 2007

The purpose of this study is to consider various characteristics in the graffiti-look in the modem fashion by interpreting meanings and properties of graffiti, transferred from street art to a new main stream in art. The scope of this study is limited to works from the 1990s to the present, and the materials for the literatures and exploratory study are fashion-related portfolios and the domestic and foreign fashion magazines. The first characteristic is satire. The graffiti-look conveys directly or indirectly with phrase or symbol various messages of politics, social ideology, wealth and poverty, environmental pollution, anti-war, etc. Body is even more used for graffitiand designers express freely their identity or ideology through the formative style of graffiti. The second characteristic is pleasure. Fantastic expressions from a fairy-tale or fable in the graffiti-look give humor meaning freedom and sense of liberation in a sense of catharsis to the modem people's emotion. The graffiti-look uses graffiti works to introduce its original message of humanism, happiness, humor, etc. to clothing; as a result, the graffiti-look features pleasure. The third characteristic iscommercial application. Brand logo designed by graffiti style is decorated with clothing, accessory, or ornament. This may not only emphasize brand name through lingual function of graffiti, but also be used for a distinctive marketing strategy against other brands. Logo which is regarded motive or pattern of design leaves a image instead of a meaning and performs a design function stressing formative sense.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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• pp.135-140
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• 2009

SF에 등장하는 다양한 돌연변이 캐릭터들은 상당히 긴 계보를 지닌다. 고대 그리스의 반인 반수 사티로스에서부터 늑대인간, 뱀파이어, 초능력자, 기생물체에 이르기까지 그 종류와 성격도 수백 가지에 이른다. 그러나 국내 문화콘텐츠 시장에서는 SF 장르 내 가장 유서 깊은 소재 중에 하나인 돌연변이에 대한 접근이 거의 없었을 뿐 아니라, SF 분야 자체에 대한 논의도 활발하지 못했다. 본 논문에서는 SF에 등장하는 돌연변이 중 인간과 연관된 형태만을 선별해 '호모 뮤턴트'라고 명명하고, 그 특성과 유형에 대해 정리해 보고자 한다. 인간과 변종의 경계를 해체하는 혼종으로 때론 생물학적인 감수성과 인격을 내제한 채, 인간과 공생 파트너로서의 가능성까지 내비치는 SF 속 '호모 뮤턴트'를 살펴봄으로써, 인류사가 가졌던 그에 대한 끊임없는 상상력이 당대의 시대상과 어떤 관계를 맺고 있는지 분석해 보고자 한다. 나아가 '호모 뮤턴트'가 문화콘텐츠로서 명실 공히 '흥행코드'로 사용될 수밖에 없는 이유도 도출해 보고자 한다.

• International journal of advanced smart convergence
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• 제9권3호
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• pp.192-198
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• 2020

The 3D point cloud is a key technology of object detection for virtual reality and augmented reality. In order to apply various areas of object detection, it is necessary to obtain 3D information and even color information more easily. In general, to generate a 3D point cloud, it is acquired using an expensive scanner device. However, 3D and characteristic information such as RGB and depth can be easily obtained in a mobile device. GNN (Graph Neural Network) can be used for object detection based on these characteristics. In this paper, we have generated RGB and RGBD by detecting basic information and characteristic information from the KITTI dataset, which is often used in 3D point cloud object detection. We have generated RGB-GNN with i-GNN, which is the most widely used LiDAR characteristic information, and color information characteristics that can be obtained from mobile devices. We compared and analyzed object detection accuracy using RGBD-GNN, which characterizes color and depth information.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.687-690
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• 1999

Many high-resolution algorithms based on the eigen-decomposition analysis of observed covariance matrix, such as MVE, MUSIC, and EVM, have been proposed. However, the resolution of spectral estimates for these algorithms is severely degraded when Signal-to-Noise Ratio (SNR) is low and arrival angles of signal are close to each other. And EVM and MUSIC is powerful for the characteristic of SNR. But have the limitation that the number of signals presented is known. While MVE is bad the characteristic of SNR. In this study, we propose a modified MVE to enhance the resolution for Direction-Of-Arrival (DOA) estimation of underwater acoustic signal. This is to remove the limitation that existing algorithms should know the information for the number of signals. Because the algorithms founded on the eigen value estimate DOA with only the noise subspace, they have the high-resolution characteristic. And then, with the method reducing the effect of the signal subspace, we are to reduce the degradation because of complementary relationship between the signal subspace and the noise subspace. This paper, with using the simulation data, we have estimated the proposed algorithms, compared it with other high-resolution algorithms. The simulation results show that the modified MVE proposed is accurate and has a better resolution even though SNR is low, under the same condition.

• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.209-214
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• 2010

The Raman shift of water vapor is 3657 $cm^{-1}$, and this Raman signal can be easily separated from other Raman signals or elastic signals. However, it is difficult to make simultaneous Raman measurements on the three phases of water, namely, ice water, liquid water, and water vapor. This is because we must consider the overlap between their Raman spectra. Therefore, very few groups have attempted to make Raman simultaneous measurements even on two elements (water vapor and liquid water, or water vapor and ice water). We have made an effort to find three characteristic Raman wavelengths that correspond to the three phases of water after measuring full Raman spectra of water on particular days that are rainy, snowy or clear. Finally, we have found that the 401-nm, 404-nm, and 408-nm wavelengths are the most characteristic Raman wavelengths that are representative of the water phases when we are using the 355-nm laser wavelength for making measurements.

• 전기학회논문지P
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• 제53권2호
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• pp.43-50
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• 2004

Percentage differential characteristic relaying(PDR) has been recognized as the principal basis for power transformer protection. Second harmonic restraint PDR has been widely used for magnetizing inrush in practice. Nowadays, relaying signals can contain 2nd harmonic component to a large extent even in a normal state, and 2nd harmonic ratio indicates a tendency of relative reduction because of the advancement of material. Further, as the power system voltage becomes higher and more underground cables are used, larger 2nd harmonic component in the differential current under internal fault is observed. And then, conventional 2nd harmonic restraint PDR exposes some doubt in reliability. It is, therefore, necessary to develop a new algorithm for performance improvement of conventional protective relaying. This paper proposes an advanced protective relaying algorithm by using voltage-current trend and flux-differential current slope characteristic. To evaluate the performance of the proposed algorithm, we have made comparative studies of PDR, fuzzy relaying and DWT relaying. The paper is constructed power system model including power transformer, utilizing the WatATP, and data collection is made through simulation of various internal faults and inrush. As the results of test, the new proposed algorithm was proven to be faster and more reliable.

• Communications for Statistical Applications and Methods
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• 제26권2호
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• pp.205-216
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• 2019

Diagnostic tests in medical fields detect or diagnose a disease with results measured by continuous or discrete ordinal data. The performance of a diagnostic test is summarized using the receiver operating characteristic (ROC) curve and the area under the curve (AUC). The diagnostic test is considered clinically useful if the outcomes in actually-positive cases are higher than actually-negative cases and the ROC curve is concave. In this study, we apply the stochastic ordering method in a Bayesian hierarchical model to estimate the proper ROC curve and AUC when the diagnostic test results are measured in discrete ordinal data. We compare the conventional binormal model and binormal model under stochastic ordering. The simulation results and real data analysis for breast cancer indicate that the binormal model under stochastic ordering can be used to estimate the proper ROC curve with a small bias even though the sample sizes were small or the sample size of actually-negative cases varied from actually-positive cases. Therefore, it is appropriate to consider the binormal model under stochastic ordering in the presence of large differences for a sample size between actually-negative and actually-positive groups.

• 한국초전도ㆍ저온공학회논문지
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• 제9권1호
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• pp.37-42
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• 2007

We are developing a 22.9 kV/25 MVA superconducting fault current limiting(SFCL) system for a power distribution network. A Bi-2212 bulk SFCL element, which has the merits of large current capacity and high allowable electric field during fault of the power network, was selected as a candidate for our SFCL system. In this work, we experimentally investigated important characteristics of the 190 kVA Bi-2212 SFCL element in its application to the power grid e.g. DC voltage-current characteristic, AC loss, current limiting characteristic during fault, and so on. Some experimental data related to thermal and electromagnetic behaviors were also compared with the calculated ones based on numerical method. The results show that the total AC loss at rated current of the 22.9 kV/25 MVA SFCL system, consisting of one hundred thirty five 190 kVA SFCL elements, becomes likely 763 W, which is excessively large for commercialization. Numerically calculated temperature of the SFCL element in some sections is in good agreement with the measured one during fault. Local temperature distribution in the190 kVA SFCL element is greatly influenced by non-uniform critical current along the Bi-2212 bulk SFCL element, even if its non-uniformity becomes a few percentages.

• 제어로봇시스템학회논문지
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• 제10권3호
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• pp.205-215
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• 2004

The characteristic ratio assignment (CRA) method〔1〕 is new polynomial approach which allows to directly address the transient responses such as overshoot and speed of response time in time domain specifications. The method is based on the relationships between time response and characteristic ratios($\alpha_i$ ) and generalized time constant (T), which are defined in terms of coefficients of characteristic polynomial. However, even though the CRA can apply to developing a linear controller that meets good transient responses, there are still some fundamental questions to be explored. For the purpose of this, we have analyzed several sensitivities of a linear system with respect to the changes of coefficients itself and $\alpha_i$ of denominator polynomial. They are (i) the unnormalized root sensitivity : to determine how the poles change as $\alpha_i$ changes, and (ii) the function sensitivity to determine the sensitivity of step response to the change of o, and to analyze the sensitivity of frequency response as o, changes. As an other important result, it is shown that, under any fixed T and coefficient of the lowest order of s in denominator, the step response is dominantly affected merely by $\alpha_1, alpha_2 and alpha_3$ regardless of the order of denominator higher than 4. This means that the rest of the$\alpha_i$ s have little effect on the step response. These results provide some useful insight and background theory when we select $\alpha_i$ and T to compose a reference model, and in particular when we design a low order controllers such as PID controller.