• Title/Summary/Keyword: ideal feature

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Flow Characteristics of Cryogenic Oxidizer in Liquid Propellant Rocket Engine (액체로켓 엔진에서의 극저온 산화제의 유동 특성)

  • 조남경;정용갑;문일윤;한영민;이수용;정상권
    • Journal of the Korean Society of Propulsion Engineers
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    • v.6 no.4
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    • pp.15-23
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    • 2002
  • In most cryogenic liquid rocket engines, liquid oxygen manifold and injector are not thermally insulated from room temperature environment fur reducing system complexity and the weight. This feature of cryogenic liquid rocket engine results in the situation that cryogenic liquid oxygen flow is easy to be vaporized especially in the vicinity of the manifold and the injector wall. The research in this paper is focused on two-phase flow phenomena of liquid oxygen in rocket engine. Vapor fraction was estimated by comparing the measured two-phase flow pressure drop in engine manifold and the injector with ideal single phase pressure drop. Heat flux into cryogenic flow is estimated by measuring the wall temperature on the engine manifold to examine boiling characteristics. Suitable correlations for cryogenic two-phase flow were also reviewed to see their applicability. In addition, the effect of vapor generation in liquid rocket engine manifold and injector on engine performance and stability was considered.

A Study on Relevant Aspects of "Nature" and "Elegant Beauty" Appearring in Cho, Chi-Hoon's Poems and Poetics (조지훈 시와 시론에 나타난 자연과 우아미의 관련 양상)

  • Lee, Chan
    • Cross-Cultural Studies
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    • v.41
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    • pp.275-298
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    • 2015
  • This paper is to examine in detail the relevant aspects of "Nature" and "Elegant Beauty" appearring in Cho, Chi-Hoon's poems and poetics. It uses the same context to explain the reasons and grounds for the inevitable, corresponding closely to his poetry and poetics. It is the core of Cho Chi-Hoon's poetry to determine "natural" new artistic views and his vision of ultra-modernism. This is consistent with the precise feature of "Elegant Beauty" in the midst of aesthetic categories profoundly discusseing his poetics. He regards a "lyric" as a vision of ultra-modernism, to overcome divisions and conflicts of values, "Truth Good Beauty", which was caused by modern science. Furthermore, it includes many social issues in accordance with the differentiation and specialization of each area. It is inferred to have been attempted to produce specifically was found to shape new images of "Nature" in the dimension of his poems, "Elegant Beauty" is overwhelmed with the aesthetic excellence of the other categories in the dimension of his poetics in this context.

Development of Micro-Tubular Perovskite Cathode Catalyst with Bi-Functionality on ORR/OER for Metal-Air Battery Applications

  • Jeon, Yukwon;Kwon, Ohchan;Ji, Yunseong;Jeon, Ok Sung;Lee, Chanmin;Shul, Yong-Gun
    • Korean Chemical Engineering Research
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    • v.57 no.3
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    • pp.425-431
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    • 2019
  • As rechargeable metal-air batteries will be ideal energy storage devices in the future, an active cathode electrocatalyst is required with bi-functionality on both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) during discharge and charge, respectively. Here, a class of perovskite cathode catalyst with a micro-tubular structure has been developed by controlling bi-functionality from different Ru and Ni dopant ratios. A micro-tubular structure is achieved by the activated carbon fiber (ACF) templating method, which provides uniform size and shape. At the perovskite formula of $LaCrO_3$, the dual dopant system is successfully synthesized with a perfect incorporation into the single perovskite structure. The chemical oxidation states for each Ni and Ru also confirm the partial substitution to B-site of Cr without any changes in the major perovskite structure. From the electrochemical measurements, the micro-tubular feature reveals much more efficient catalytic activity on ORR and OER, comparing to the grain catalyst with same perovskite composition. By changing the Ru and Ni ratio, the $LaCr_{0.8}Ru_{0.1}Ni_{0.1}O_3$ micro-tubular catalyst exhibits great bi-functionality, especially on ORR, with low metal loading, which is comparable to the commercial catalyst of Pt and Ir. This advanced catalytic property on the micro-tubular structure and Ru/Ni synergy effect at the perovskite material may provide a new direction for the next-generation cathode catalyst in metal-air battery system.

Development of Fast Posture Classification System for Table Tennis Robot (탁구 로봇을 위한 빠른 자세 분류 시스템 개발)

  • Jin, Seongho;Kwon, Yongwoo;Kim, Yoonjeong;Park, Miyoung;An, Jaehoon;Kang, Hosun;Choi, Jiwook;Lee, Inho
    • The Journal of Korea Robotics Society
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    • v.17 no.4
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    • pp.463-476
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    • 2022
  • In this paper, we propose a table tennis posture classification system using a cooperative robot to develop a table tennis robot that can be trained like a real game. The most ideal table tennis robot would be a robot with a high joint driving speed and a high degree of freedom. Therefore, in this paper, we intend to use a cooperative robot with sufficient degrees of freedom to develop a robot that can be trained like a real game. However, cooperative robots have the disadvantage of slow joint driving speed. These shortcomings are expected to be overcome through quick recognition. Therefore, in this paper, we try to quickly classify the opponent's posture to overcome the slow joint driving speed. To this end, learning about dynamic postures was conducted using image data as input, and finally, three classification models were created and comparative experiments and evaluations were performed on the designated dynamic postures. In conclusion, comparative experimental data demonstrate the highest classification accuracy and fastest classification speed in classification models using MLP (Multi-Layer Perceptron), and thus demonstrate the validity of the proposed algorithm.

Modern Concepts of Restructured Meat Production and Market Opportunities

  • Abdul Samad;AMM Nurul Alam;Swati Kumari;Md. Jakir Hossain;Eun-Yeong Lee;Young-Hwa Hwang;Seon-Tea Joo
    • Food Science of Animal Resources
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    • v.44 no.2
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    • pp.284-298
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    • 2024
  • Restructured meat (RM) products are gaining importance as an essential component of the meat industry due to consumers' interest in health benefits. RM products imply the binding or holding of meat, meat by-products, and vegetable proteins together to form a meat product with meat's sensory and textural properties. RM products provide consumers with diversified preferences like the intake of low salt, low fat, antioxidants, and high dietary fiber in meat products. From the point of environmental sustainability, RM may aid in combining underutilized products and low-valued meat by adequately utilizing them instead of dumping them as waste material. RM processing technique might also help develop diversified and new hybrid meat products. It is crucial to have more knowledge on the quality issues, selection of binding agents, their optimum proportion, and finally, the ideal processing techniques. It is observed in this study that the most crucial feature of RM could be its healthy products with reduced fat content, which aligns with the preferences of health-conscious consumers who seek low-fat, low-salt, high-fiber options with minimal synthetic additives. This review briefly overviews RM and the factors affecting the quality and shelf life. Moreover, it discusses the recent studies on binding agents in processing RM products. Nonetheless, the recent advancements in processing and market scenarios have been summarized to better understand future research needs. The purpose of this review was to bring light to the ways of sustainable and economical food production.

GPU Based Feature Profile Simulation for Deep Contact Hole Etching in Fluorocarbon Plasma

  • Im, Yeon-Ho;Chang, Won-Seok;Choi, Kwang-Sung;Yu, Dong-Hun;Cho, Deog-Gyun;Yook, Yeong-Geun;Chun, Poo-Reum;Lee, Se-A;Kim, Jin-Tae;Kwon, Deuk-Chul;Yoon, Jung-Sik;Kim3, Dae-Woong;You, Shin-Jae
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.80-81
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    • 2012
  • Recently, one of the critical issues in the etching processes of the nanoscale devices is to achieve ultra-high aspect ratio contact (UHARC) profile without anomalous behaviors such as sidewall bowing, and twisting profile. To achieve this goal, the fluorocarbon plasmas with major advantage of the sidewall passivation have been used commonly with numerous additives to obtain the ideal etch profiles. However, they still suffer from formidable challenges such as tight limits of sidewall bowing and controlling the randomly distorted features in nanoscale etching profile. Furthermore, the absence of the available plasma simulation tools has made it difficult to develop revolutionary technologies to overcome these process limitations, including novel plasma chemistries, and plasma sources. As an effort to address these issues, we performed a fluorocarbon surface kinetic modeling based on the experimental plasma diagnostic data for silicon dioxide etching process under inductively coupled C4F6/Ar/O2 plasmas. For this work, the SiO2 etch rates were investigated with bulk plasma diagnostics tools such as Langmuir probe, cutoff probe and Quadruple Mass Spectrometer (QMS). The surface chemistries of the etched samples were measured by X-ray Photoelectron Spectrometer. To measure plasma parameters, the self-cleaned RF Langmuir probe was used for polymer deposition environment on the probe tip and double-checked by the cutoff probe which was known to be a precise plasma diagnostic tool for the electron density measurement. In addition, neutral and ion fluxes from bulk plasma were monitored with appearance methods using QMS signal. Based on these experimental data, we proposed a phenomenological, and realistic two-layer surface reaction model of SiO2 etch process under the overlying polymer passivation layer, considering material balance of deposition and etching through steady-state fluorocarbon layer. The predicted surface reaction modeling results showed good agreement with the experimental data. With the above studies of plasma surface reaction, we have developed a 3D topography simulator using the multi-layer level set algorithm and new memory saving technique, which is suitable in 3D UHARC etch simulation. Ballistic transports of neutral and ion species inside feature profile was considered by deterministic and Monte Carlo methods, respectively. In case of ultra-high aspect ratio contact hole etching, it is already well-known that the huge computational burden is required for realistic consideration of these ballistic transports. To address this issue, the related computational codes were efficiently parallelized for GPU (Graphic Processing Unit) computing, so that the total computation time could be improved more than few hundred times compared to the serial version. Finally, the 3D topography simulator was integrated with ballistic transport module and etch reaction model. Realistic etch-profile simulations with consideration of the sidewall polymer passivation layer were demonstrated.

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Anomaly Detection for User Action with Generative Adversarial Networks (적대적 생성 모델을 활용한 사용자 행위 이상 탐지 방법)

  • Choi, Nam woong;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.25 no.3
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    • pp.43-62
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    • 2019
  • At one time, the anomaly detection sector dominated the method of determining whether there was an abnormality based on the statistics derived from specific data. This methodology was possible because the dimension of the data was simple in the past, so the classical statistical method could work effectively. However, as the characteristics of data have changed complexly in the era of big data, it has become more difficult to accurately analyze and predict the data that occurs throughout the industry in the conventional way. Therefore, SVM and Decision Tree based supervised learning algorithms were used. However, there is peculiarity that supervised learning based model can only accurately predict the test data, when the number of classes is equal to the number of normal classes and most of the data generated in the industry has unbalanced data class. Therefore, the predicted results are not always valid when supervised learning model is applied. In order to overcome these drawbacks, many studies now use the unsupervised learning-based model that is not influenced by class distribution, such as autoencoder or generative adversarial networks. In this paper, we propose a method to detect anomalies using generative adversarial networks. AnoGAN, introduced in the study of Thomas et al (2017), is a classification model that performs abnormal detection of medical images. It was composed of a Convolution Neural Net and was used in the field of detection. On the other hand, sequencing data abnormality detection using generative adversarial network is a lack of research papers compared to image data. Of course, in Li et al (2018), a study by Li et al (LSTM), a type of recurrent neural network, has proposed a model to classify the abnormities of numerical sequence data, but it has not been used for categorical sequence data, as well as feature matching method applied by salans et al.(2016). So it suggests that there are a number of studies to be tried on in the ideal classification of sequence data through a generative adversarial Network. In order to learn the sequence data, the structure of the generative adversarial networks is composed of LSTM, and the 2 stacked-LSTM of the generator is composed of 32-dim hidden unit layers and 64-dim hidden unit layers. The LSTM of the discriminator consists of 64-dim hidden unit layer were used. In the process of deriving abnormal scores from existing paper of Anomaly Detection for Sequence data, entropy values of probability of actual data are used in the process of deriving abnormal scores. but in this paper, as mentioned earlier, abnormal scores have been derived by using feature matching techniques. In addition, the process of optimizing latent variables was designed with LSTM to improve model performance. The modified form of generative adversarial model was more accurate in all experiments than the autoencoder in terms of precision and was approximately 7% higher in accuracy. In terms of Robustness, Generative adversarial networks also performed better than autoencoder. Because generative adversarial networks can learn data distribution from real categorical sequence data, Unaffected by a single normal data. But autoencoder is not. Result of Robustness test showed that he accuracy of the autocoder was 92%, the accuracy of the hostile neural network was 96%, and in terms of sensitivity, the autocoder was 40% and the hostile neural network was 51%. In this paper, experiments have also been conducted to show how much performance changes due to differences in the optimization structure of potential variables. As a result, the level of 1% was improved in terms of sensitivity. These results suggest that it presented a new perspective on optimizing latent variable that were relatively insignificant.

A Study on the Non-residential Building Envelope Remodeling for Energy Efficiency (비주거용 건물의 외피 리모델링을 통한 에너지성능향상 방안에 관한 연구)

  • Jang, Hyun-Sook;Lee, Sang-Ho
    • Korean Journal of Construction Engineering and Management
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    • v.13 no.6
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    • pp.3-12
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    • 2012
  • The slowdown of private building industry resulted in growth of remodeling market as a way to improve energy performance. Remodeling is considered more cost-effective and eco-friendly approach for energy efficient building than new construction. Since 2008, Seoul has promoted Building Retrofit Project (BRP) preponderantly to attract energy-saving renovation by supporting building owners to switch building system into energy-saving system when they remodel their old buildings. According to 2012 press release, 254 Private sectors participated in this green building project and annually reduced 41000ton of greenhouse gas emission, 14000TOE, which also result in 7.5 billion won energy cost savings per year. The paper focuses on the building envelope remodeling as a way to improve energy efficiency. Different components of the building envelope such as wall insulation, window, and shading, were applied to the baseline model and the comparison was analyzed to come up with the ideal solution. This study only assesses the building envelope as to suggest the way to redesign the better energy performing building. Offering solution focusing on the architectural feature is essential because it will provide basic information and standard when remodeling a building for energy efficiency, especially, for the nonresidential buildings used as rental offices.

Impedance Spectroscopy Models for X5R Multilayer Ceramic Capacitors

  • Lee, Jong-Sook;Shin, Eui-Chol;Shin, Dong-Kyu;Kim, Yong;Ahn, Pyung-An;Seo, Hyun-Ho;Jo, Jung-Mo;Kim, Jee-Hoon;Kim, Gye-Rok;Kim, Young-Hun;Park, Ji-Young;Kim, Chang-Hoon;Hong, Jeong-Oh;Hur, Kang-Heon
    • Journal of the Korean Ceramic Society
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    • v.49 no.5
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    • pp.475-483
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    • 2012
  • High capacitance X5R MLCCs based on $BaTiO_3$ ceramic dielectric layers exhibit a single broad, asymmetric arc shape impedance and modulus response over the wide frequency range between 1 MHz to 0.01 Hz. Analysis according to the conventional brick-layer model for polycrystalline conductors employing a series connection of multiple RC parallel circuits leads to parameters associated with large errors and of little physical significance. A new parametric impedance model is shown to satisfactorily describe the experimental spectra, which is a parallel network of one resistor R representing the DC conductivity thermally activated by 1.32 eV, one ideal capacitor C exactly representing bulk capacitance, and a constant phase element (CPE) Q with complex capacitance $A(i{\omega})^{{\alpha}-1}$ with ${\alpha}$ close to 2/3 and A thermally activated by 0.45 eV or ca. 1/3 of activation energy of DC conductivity. The feature strongly indicate the CK1 model by J. R. Macdonald, where the CPE with 2/3 power-law exponent represents the polarization effects originating from mobile charge carriers. The CPE term is suggested to be directly related to the trapping of the electronic charge carriers and indirectly related to the ionic defects responsible for the insulation resistance degradation.

A Study on TQM Strategy in Tourist Hetels (관광호텔 TQM전략에 관한 연구)

  • 구경원;이상우
    • Journal of Applied Tourism Food and Beverage Management and Research
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    • v.7
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    • pp.231-266
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    • 1997
  • TQM is a whole process of systemizing, documenting and measuring of service quality scientifically to achieve zero defects in product quality and to continue to improve the body of the product quality by itself. To have this process be improved continuously, first of all it needs to prepare an ideal environment to understand and to conform to its internal and external customers', that is every guests' and employees' expectations and demands. Then it has to be followed by the next step removing some negative aspects that could be derived from the first mentioned process The third step is to cut the cost be suitable compensation rather than an attitude trying to solve the problems in an easy way. The last essential factor for setting up TQM system is to make good use of the outstanding feature or process as it is reviewed against the superior benchmark. The purpose of this study is meet the customers' expectations and to maximize the hotel's profits by searching TQM(total quality management) strategy in hotels. To attain this research's objective, it follows these three details. Firstly, it defines TQM and its contents. Secondly, it provides the standard of hotel TQM throughout some case studies. Thirdly, it suggests TQM strategic plan in tourism hotel as one of professional management strategies. Two useful methods are used together to achieve the goal of this study. To confirm its theoretical consideration, descriptive studies by the research documents its theoretical consideration, descriptive studies by the research documents published in and out of the country is used. The other is case studies of TQM execution in real hospitality industry, which present the cases of the airline, Jefferson Memorial and the hotel. This research is targeting to demonstrate the successful TQM's exercise in a hotel industry by completing the theoretical studies and case studies on service product quality with an understanding of its importance. As it is said earlier, to lead to the successful TQM's practice, it is necessary to maintain a constant training of the employees. Secondly, it also must identify where it has to focus on to deliver a professional quality management. Thirdly, effective quality management organization needs to be build up. The manager's strong will to accomplish and the employee' active participations are the last condition to be succeed. Once again this study places an emphasis on the fact that TQM is critical to maximize the customers' satisfaction and the hotel's profitability. It is also very worthwhile to have every people working on front line recognize why the TQM is important and further more how they can contribute to improve their service quality by a positive participation and a careful observation of TQM's operating in their property.

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