• 제목/요약/키워드: Linear theory

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Studies on the Measurement of Thermal Diffusivity and Thermophysical Characteristics of Defatted and Nondefatted Starches (전분의 열확산율 측정 및 물리적 특성에 관한 연구)

  • Kim, Min-Yong;Kong, Jai-Yul;Kim, Jeong-Han;Cheong, Jin-Woong
    • Korean Journal of Food Science and Technology
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    • v.22 no.1
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    • pp.1-6
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    • 1990
  • The thermal diffusivity of defatted and nondefatted starches were measured on the basis of one dimensional semi-infinitive theory. Differential scanning calorymetry was used to study the effects of cooling rate, fat and water contents on the enthalpy and entropy changes with the cooling rate of $-2.5{\sim}10^{\circ}C/min$. Thermal diffusivity of defatted and nondefatted straches were determined to be $4.14{\times}10^{-4}{\sim}4.96{\times}10^{-4}(m^2/h),\;4.09{\times}10^{-4}{\sim}4.81{\times}10^{-4}(m^2/h)$ in unfrozen state, and $2.78{\times}10^{-3}{\sim}3.91{\times}10^{-3}(m^2/h),\;2.26{\times}10^{-3}{\sim}3.57{\times}1-^{-3}(m^2/h)$ in frozen state respectively. On decreasing temperatures in frozen state, thermal diffusivities of starches were increased and entropy and enthalpy were decreased, and more rapid cooling rates resulted in a decrease in entropy. A linear relation was observed between enthropy, enthaly and water content. Thermal diffusivity was decreased, and entropy was increasing fat content. With water content ranging from 35 to 90%, enthalpy and entropy of straches were found to be $107{\sim}216 (kcal /moi),\;0.45{\sim}0.94(kcal/mol.\;K)$, respectively.

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A simple Demonstration of the Wiener-Khinchin Theorem using a Digital Oscilloscope and Personal Computer (디지털 오실로스코프에 의한 Wiener-Khinchin 정리의 시현)

  • Jung, Se-Min
    • Korean Journal of Optics and Photonics
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    • v.24 no.5
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    • pp.245-250
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    • 2013
  • The Wiener-Khinchin theorem, which means that the autocorrelation function of a signal corresponds to the power spectrum of the signal, is very important in signal processing, spectroscopy and telecommunications engineering. However, because of needs for some relatively expensive equipments such as a correlator and the signal processing system, its demonstration in most undergraduate class is not easy so far. Recently, digital oscilloscopes whose functions can be replaced foresaid equipments are marketed with development of digital engineering. In this paper, a simple demonstration of the theorem is given by a digital storage oscilloscope and a personal computer with its theoretical background. The reason that deals again with this theorem which has been introduced in 1930 is that it has been not well informed yet to us and theoretical background of the demonstration is directly introduced from its driving process. Through deriving process of the theorem, some extended physical meanings of the impedance, power, power factor, Wiener spectrum, linear system response and, furthermore, basic idea of the Planck's quantization in the black body theory reveal themselves naturally. Hence it can be referred to lectures in general physics, modern physics, spectroscopy and material characterization experiment.

Improvement of Microphone Away Performance in the Low Frequencies Using Modulation Technique (변조 기법을 이용한 마이크로폰 어레이의 저주파 대역 특성 개선)

  • Kim, Gi-Bak;Cho, Nam-Ik
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.42 no.4 s.304
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    • pp.111-118
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    • 2005
  • In this paper, we employ the modulation technique for improving the characteristics of beamformer in the low frequencies and thus improving the overall noise reduction performance. In the 1-dimensional uniform linear microphone arrays, we can suppress the narrowband noise component using the delay-and-sum beamforming. But, for the wideband noise signal, the delay-and-sum beamformer does not work well for the reduction of low frequency component because the inter-element spacing is usually set to avoid spatial aliasing at high frequencies. Hence, the beamwidth is not uniform with respect to each frequency and it is usually wider at the low frequencies. In order to obtain the beamwidth independent of frequencies, subarray systems[1][2][3][4] and multi-beamforming[5] have been proposed. However these algorithms need large space and more microphones since they are based on the theory that the size of the array is proportional to the wavelength of the input signal. In the proposed beamformer, we reduce the low frequency noise by using modulation technique that does not need additional sensors or non-uniform spacing. More Precisely, the array signals are split into subbands, and the low frequency components are shifted to high frequencies by modulation and reduced by the delay-and-sum beamforming techniques with small size microphone array. Experimental results show that the proposed technique Provides better performance than the conventional ones, especially in the low frequency band.

Wavelet Series Analysis of Axial Members with Stress Singularities (응력특이를 갖는 축방향 부재의 웨이블렛 급수해석)

  • Woo, Kwang-Sung;Jang, Young-Min;Lee, Dong-Woo;Lee, Sang-Yun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.1
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    • pp.1-8
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    • 2010
  • The Fourier series uses a vibrating wave that possesses an amplitude that is like the one of the sine curve. Therefore, the functions used in the Fourier series do not change due to the value of the frequency and that set a limit to express irregular signals with rapid oscillations or with discontinuities in localized regions. However, the wavelet series analysis(WSA) method supplements these limits of the Fourier series by a linear combination of a suitable number of wavelets. By using the wavelet that is focused on time, it is able to give changes to the range in the cycle. Also, this enables to express a signal more efficiently that has singular configuration and that is flowing. The main objective of this study is to propose a scheme called wavelet series analysis for the application of wavelet theory to one-dimensional problems represented by the second-order elliptic equation and to evaluate theperformance of proposed scheme comparing with the finite element analysis. After a through evaluation of different types of wavelets, the HAT wavelet system is chosen as a wavelet function as well as a scaling function. It can be stated that the WSA method is as efficient as the FEA method in the case of axial bars with distributed loads, but the WSA method is more accurate than the FEA method at the singular points and its computation time is less.

Exploratory Study of Characterizing Scholarly Communication Patterns in Humanities for Facilitating Consilience in Cyberscholarship Environment: Based on Historians' Research Activities (사이버스칼러쉽 환경에서의 융복합 연구 촉진을 위한 인문학 분야 학술 커뮤니케이션 특성 파악에 관한 연구 - 역사학 분야를 중심으로 -)

  • Yu, So-Young
    • Journal of the Korean Society for Library and Information Science
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    • v.50 no.1
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    • pp.331-351
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    • 2016
  • Digitalized data and literature in scholarly community has developed the concept of digital humanities and cyberscholarship which indicate the characteristics of a new aspect and approach in scholarly activities with digitalized resources or new media. This study was performed in order to identify the changes in national research activities of art and humanities by using a multi-modal approach. The combined methodology of in-depth interview and content analysis on publishing and citing behaviors in literature was executed. The steps of research process is identified as a non-linear combination of 3 parts: developing research idea, developing the research idea to write, and submitting manuscript to publish. Prominent implementations of cyberscholarship were found in the 2nd step for accessing and using research data and literatures. Understanding the characteristics of scholar communication using cyberscholarhip factors in humanities for interdisciplinarity, sophisticating the environment of cyberscholarhip for data sharing, investing and developing archivist and archives, and providing a various platform for accelerating scholarly communication were derived by the panel discussion for developing interdisciplinary research for humanities.

The Estimation of the Constrained Modulus and the Coefficient of Consolidation from the Piezocone Penetration Test Data (피에조 콘 관입시험결과에 따른 구속탄성계수, 압밀계수 산정에 관한 연구)

  • Lee, Kise;Ku, Namshil;Han, Woonwoo
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.4
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    • pp.47-55
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    • 2007
  • Using the results of the Piezocone Penetration Test (PCPT) which were executed at the Yangsan-Mulgum site, the applicability of the interpretation methods for estimating the coefficient of consolidation ($C_v$) of soft clay was evaluated. At the same time, laboratory soil tests using the total of 172 undisturbed soft clay samples from the 44 regions of the Yangsan-Mulgum site were performed to study the differency in the coefficient of consolidation ($C_v$) compared to the results of PCPT. The calculated constrained modulus ($M_{\varepsilon}$) and coefficient of consolidation ($C_v$) using the results of consolidation laboratory tests which are based upon the consolidation theory of Terzaghi were compared with the predicted constrained modulus ($M_p$) and coefficient of consolidation ($C_{v-{M_p}}$) from the PCPT. The relationship between the predicted constrained modulus ($M_p$) and the calculated constrained modulus($M_c$) were showed good correlation. The $M_p$ by the Jones & Rust method were showed mostly similar to the calculated constrained modulus ($M_c$). The relationship between the coefficient of consolidation ($C_v$) obtained from the consolidation tests and the calculated coefficient of consolidation ($C_{v-{M_p}}$) were showed a linear relationship. The results of the calculated coefficient of consolidation ($C_{v-{M_p}}$) were about 54% of the value of the coefficient of consolidation ($C_v$) obtained from the consolidation tests.

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Proposal of Sliding Stability Assessment Formulas for an Interlocking Caisson Breakwater under Wave Forces (파랑하중에 대한 인터로킹 케이슨 방파제의 미끌림 안정성 평가식 제안)

  • Park, Woo-Sun;Won, Deokhee;Seo, Jihye
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.2
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    • pp.77-82
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    • 2017
  • Recently, the possibility of abnormal waves of which height is greater than design wave height have been increased due to the climate change, and therefore it has been urgent to secure the stability for harbor structures. As a countermeasure for improving the stability of conventional caisson breakwaters, a method has been proposed in which adjacent caissons are interlocked with each other to consecutively resist the abnormal wave forces. In order to reflect this research trend, the reduction effect of the maximum wave force resulted from introducing a long caisson has been presented in the revision to the design criteria for ports and fishing harbors and commentary. However, no method has been proposed to evaluate the stability of interlocking caisson breakwater. In this study, we consider the effect of the phase difference of the oblique incidence of the wave based on the linear wave theory and apply the Goda pressure formula for considering design wave pressure distribution in the vertical direction. Sliding stability assessment formula of an interlocking caisson breakwater is proposed for regular, irregular, and multi-directional irregular wave conditions.

A Method to Develop Security System through the Analysis on Dangerous Case (위해사례분석을 통한 경호제도의 발전방안)

  • Yu, Hyung-Chang;Kim, Tae-Min
    • Korean Security Journal
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    • no.16
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    • pp.161-187
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    • 2008
  • The purpose of this study is to suggest a development method of current Korean security system by analyzing the problems shown in the performance of security work in relation to the terrorism, which is enlarging in the word, from various aspects. In order to perform the study, the researcher considered the basic theory concerned to current Korean law concerned to security, principle and methodology of security, terror and new terrorism. The researcher performed the study by selecting qualitative case study focused on Park Geun-Hye case. Through the study, the methods to develop Korean security system are as follows. First, from the legal aspect, it is necessary to establish the law concerned to terrorism prevention and important person security. Moreover, it is necessary to search for the development of private security by revising Security Industry Act, which is a legal ground of private security. Second, it is necessary to improve and reinforce education & training program, which is not still divided in detail from the aspect of private security cultivation. Moreover, it is necessary to activate personal protection work and enlarge market through Security Industry Act and make an effort to change social recognition over security, which is devaluated in the society. From the viewpoint, national license about private security shall be adopted. The department of president security, which is a representative of official security, shall transfer the advanced technology to private security organization. Third, from the aspect of operation, the operation of security based on SCE principle, human shield principle, the nearest person's protection principle, body extension principle, linear protection principle and evacuation priority principle is required. Therefore, the priority shall be given to preventive security and thorough security plan shall be made for the operation.

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Measuring of Gender Inequality: Asymmetry of Marriage Table with respect to Educational Level (교육수준 별 혼인표의 비대칭성으로 살펴본 남녀불평등지수)

  • 이명진
    • Korea journal of population studies
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    • v.25 no.1
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    • pp.33-50
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    • 2002
  • This study examines cross-national patterns of asymmetry of marriage tables with respect to educational level and tries to measure the degree of gender inequality across nations. A Primary assumption of the study is that gender inequality inhibits symmetric marriage between men and women. As men and women differ more in status, the rate of symmetric marriage between them declines thus producing asymmetric marriage with respect to social status. More specifically, the main object of the study is to develop statistical models and index with which to assess the patterns and degree of asymmetric marriage. Additionally, it is intended to assess the appropriateness of several theoretical perspectives for explaining these variations identified by the statistical models. Two most important such perspectives are industrialism and theory of politics and culture. To answer these questions, this study relies on twenty-seven marriage tables with respect to educational level, some from published tables, and some extracted from other sources. The main findings of the study are: (1) compared to less industrialized countries, more industrialized countries have lower degrees of asymmetric marriage(gender inequality) with respect to educational level, and (2) other things being equal, differences in politics and culture seem to have the some impact on marriage pattern; for instance, social democracy and state socialism reduce the degree of asymmetric marriage while the high emphasis on gender-based hierarchy in Asian countries seems to increase it In short, these results suggest a weaker or modified version of industrialists That is, while with economic growth most nations show a decline in the degrees of asymmetric marriage with respect to social status, for some nations the degrees of asymmetric marriage are affected by their specific politics or cultures.

Non-linear Relationship Between IP Proportion of Startup and Financing Performance: Moderating Role of Founder's Education Level (스타트업의 지식재산 비중과 자금조달의 비선형 관계: 창업자 지식수준의 조절효과)

  • Chung, Doohee
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.14 no.5
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    • pp.1-11
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    • 2019
  • Financing plays an important role in the survival and growth of startups. This study investigates key factors that improve startup financing performance. To this end, we analyze the relationship between the proportion of intellectual property and the financing performance. In addition, this study also examine the impact of the founder's education level on the financing of startups, and the moderating effect of the founder's education level on the relationship between intellectual property proportion and financing. Based on the survey data of 331 startups, this study found that the proportion of intellectual property and the financing performance have an inverted U-shaped nonlinear relationship. While the founder's education level has a positive impact on the financing performance, it negatively moderate the relationship between the intellectual property proportion and the financing performance. Through these findings, this study suggests that it is necessary to maintain an adequate proportion of intellectual property in order to maximize startup financing performance. The higher education level of founder enhances the startup financing. Since the founder's education level weaken the effect of intellectual proporty's effect on startup financing, however, startups need to control the proportion of intellectual property to improving financing according to the founder's education level. Based on signal theory, this study proposes a new strategy of intellectual property to enhance startup financing performance.