• Title, Summary, Keyword: 비선형 해석

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Analysis of Interactions in Multiple Genes using IFSA(Independent Feature Subspace Analysis) (IFSA 알고리즘을 이용한 유전자 상호 관계 분석)

  • Kim, Hye-Jin;Choi, Seung-Jin;Bang, Sung-Yang
    • Journal of KIISE:Computer Systems and Theory
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    • v.33 no.3
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    • pp.157-165
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    • 2006
  • The change of external/internal factors of the cell rquires specific biological functions to maintain life. Such functions encourage particular genes to jnteract/regulate each other in multiple ways. Accordingly, we applied a linear decomposition model IFSA, which derives hidden variables, called the 'expression mode' that corresponds to the functions. To interpret gene interaction/regulation, we used a cross-correlation method given an expression mode. Linear decomposition models such as principal component analysis (PCA) and independent component analysis (ICA) were shown to be useful in analyzing high dimensional DNA microarray data, compared to clustering methods. These methods assume that gene expression is controlled by a linear combination of uncorrelated/indepdendent latent variables. However these methods have some difficulty in grouping similar patterns which are slightly time-delayed or asymmetric since only exactly matched Patterns are considered. In order to overcome this, we employ the (IFSA) method of [1] to locate phase- and shut-invariant features. Membership scoring functions play an important role to classify genes since linear decomposition models basically aim at data reduction not but at grouping data. We address a new function essential to the IFSA method. In this paper we stress that IFSA is useful in grouping functionally-related genes in the presence of time-shift and expression phase variance. Ultimately, we propose a new approach to investigate the multiple interaction information of genes.

Development of Site Classification System and Modification of Design Response Spectra considering Geotechnical Site Characteristics in Korea (II) - Development of Site Classification System (국내 지반특성에 적합한 지반분류 방법 및 설계응답스펙트럼 개선에 대한 연구 (II) - 지반분류 개선방법)

  • Yoon, Jong-Ku;Kim, Dong-Soo;Bang, Eun-Seok
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.2
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    • pp.51-62
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    • 2006
  • In the companion paper (I-Problem Statements of the Current Seismic Design Code), the current Korean seismic design code is required to be modified considering site characteristics in Korea for the reliable estimation of site amplification. In this paper, three site classification methods based on the mean shear wave velocity of the top 30m $V_{S30}$, fundamental site periods $(T_G)$ and bedrock depth were investigated and compared with each other to determine the best classification system. Not enough of a difference in the standard deviation of site coefficients $(F_a\;and\;F_v)$ to determine the best system, and neither is the difference between the average spectral accelerations and the design response spectrum of each system. However, the amplification range of RRS values based on $T_G$ were definitely concentrated on a narrow band than other classification system. It means that sites which have a similar behavior during earthquake will be classified as the same site category at the site classification system based on $T_G$. The regression curves between site coefficients and $T_G$ described the effect of soil non linearity well as the rock shaking intensity increases than the current method based on $V_{S30}$. Furthermore, it is unambiguous to determine sue category based on $T_G$ when the site investigation is performed to shallower depth less than 30m, whereas the current $V_{S30}$ is usually calculated fallaciously by extrapolating the $V_s$ of bedrock to 30m. From the results of this study, new site classification system based on $T_G$ was recommended for legions of shallow bedrock depth in Korea.

Normal Predictive Values of Spirometry in Korean Population (한국인의 정상 폐활량 예측치)

  • Choi, Jung Keun;Paek, Domyung;Lee, Jeoung Oh
    • Tuberculosis and Respiratory Diseases
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    • v.58 no.3
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    • pp.230-242
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    • 2005
  • Background : Spirometry should be compared with the normal predictive values obtained from the same population using the same procedures, because different ethnicity and different procedures are known to influence the spirometry results. This study was performed to obtain the normal predictive values of the Forced Vital Capacity(FVC), Forced Expiratory Volume in 1 Second($FEV_1$), Forced Expiratory Volume in 6 Seconds($FEV_6$), and $FEV_1/FVC$ for a representative Korean population. Methods : Based on the 2000 Population Census of the National Statistical Office of Korea, stratified random sampling was carried out to obtain representative samples of the Korean population. This study was performed as a part of the National Health and Nutrition Survey of Korea in 2001. The lung function was measured using the standardized methods and protocols recommended by the American Thoracic Society. Among those 4,816 subjects who had performed spirometry performed, there was a total of 1,212 nonsmokers (206 males and 1,006 females) with no significant history of respiratory diseases and symptoms, with clear chest X-rays, and with no significant exposure to respiratory hazards subjects. Their residence and age distribution was representative of the whole nation. Mixed effect models were examined based on the Akaike's information criteria in statistical analysis, and those variables common to both genders were analyzed by regression analysis to obtain the final equations. Results : The variables affecting the normal predicted values of the FVC and $FEV_6$ for males and females were $age^2$, height, and weight. The variables affecting the normal predicted values of the $FEV_1$ for males and females were $age^2$, and height. The variables affecting the normal predicted values of the $FEV_1/FVC$ for male and female were age and height. Conclusion : The predicted values of the FVC and $FEV_1$ was higher in this study than in other Korean or foreign studies, even though the difference was < 10%. When compared with those predicted values for Caucasian populations, the study results were actually comparable or higher, which might be due to the stricter criteria of the normal population and the systemic quality controls applied to the whole study procedures together with the rapid physical growth of the younger generations in Korea.

A Study on Air Resistance and Greenhouse Gas Emissions of an Ocean Leisure Planning Boat (해양레저용 활주형선의 공기저항 및 온실 가스 배출에 대한 연구)

  • Kim, Y.S.;Hwang, S.K.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.16 no.3
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    • pp.202-210
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    • 2013
  • As incomes increase, interest in ocean leisure picks up. As a result, a lot of research and developments on hull form design and production of planing boats, mostly used for ocean leisure, are needed. Analysis in researches on resistance of planing boats shows that resistance characteristic of planing boats is different from resistance characteristic of general boats because the former is fast, and its wetted surface is very small. Using Savitsky formula widely used in the calculation of effective horse power in shipbuildingyards, and propulsion system and engine manufacturers, this study calculated total resistance of a research planing boat. Then it analyzed the flow characteristics of the planing boat through theoretical analysis and wind tunnel experiment, and computed air resistance and lift force by changes of speed and trim angle. It also compared and analyzed result of theoretical analysis and experiment of the ratio of air resistance to total resistance under variations of velocity and trim angle. When the study is used to estimate more accurate effective horse power, it is expected to remedy abuses of unnecessarily installing high-powered engine. As nature disasters due to abnormal changes of weather increase, interest in greenhouse gas grows. International Maritime Organization (IMO) legislated Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI) to reduce ship greenhouse gas emissions. But this index will be applied to over 400 tons ships, small ships, emitting more greenhouse gases than larege ships per unit power, will dodge the regulations. Thus, this study indicated a problem by calculating greenhouse gas emissions of an ocean leisure planning boat (a small ship), and suggested the need for EEDI of small ships.

Shape Scheme and Size Discrete Optimum Design of Plane Steel Trusses Using Improved Genetic Algorithm (개선된 유전자 알고리즘을 이용한 평면 철골트러스의 형상계획 및 단면 이산화 최적설계)

  • Kim, Soo-Won;Yuh, Baeg-Youh;Park, Choon-Wok;Kang, Moon-Myung
    • Journal of Korean Association for Spatial Structures
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    • v.4 no.2
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    • pp.89-97
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    • 2004
  • The objective of this study is the development of a scheme and discrete optimum design algorithm, which is based on the genetic algorithm. The algorithm can perform both scheme and size optimum designs of plane trusses. The developed Scheme genetic algorithm was implemented in a computer program. For the optimum design, the objective function is the weight of structures and the constraints are limits on loads and serviceability. The basic search method for the optimum design is the genetic algorithm. The algorithm is known to be very efficient for the discrete optimization. However, its application to the complicated structures has been limited because of the extreme time need for a number of structural analyses. This study solves the problem by introducing the size & scheme genetic algorithm operators into the genetic algorithm. The genetic process virtually takes no time. However, the evolutionary process requires a tremendous amount of time for a number of structural analyses. Therefore, the application of the genetic algorithm to the complicated structures is extremely difficult, if not impossible. The scheme genetic algorithm operators was introduced to overcome the problem and to complement the evolutionary process. It is very efficient in the approximate analyses and scheme and size optimization of plane trusses structures and considerably reduces structural analysis time. Scheme and size discrete optimum combined into the genetic algorithm is what makes the practical discrete optimum design of plane fusses structures possible. The efficiency and validity of the developed discrete optimum design algorithm was verified by applying the algorithm to various optimum design examples: plane pratt, howe and warren truss.

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An Exploratory Study on Korean 20's Consuming Behaviors in Luxuries and Imitations (우리나라 20대 소비자의 명품 및 명품모방품 소비행태에 관한 탐색적 연구)

  • Koh, In Kon
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.10 no.2
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    • pp.77-84
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    • 2015
  • According to a recent survey, the sales amount of luxuries and imitations is getting larger. Especially young consumers in 2,30's have a strong desire to own luxuries, so I tried to build a theoretical base on the 20's consuming trend. Meanwhile, targeting university students who represent consumers in 20's, I investigated the recognition of luxuries, shopping experience, main shopping items, monthly spending money, and future purchase intention. I also investigated shopping experience of imitation, main shopping items, purchase reasons, and future purchase intention. I tried to suggest lots of academic and practical implications in marketing strategy building of luxury brand, aiming young consumers in 20's. On the social-psychological view point, young generation have relatively weak sense of control or self-efficacy. So, they are easily submerged in conspicuous consumption by the atmosphere around. As a result of empirical research, I found that Korean students recognized luxuries as excellent in quality, or the world famous brand. In particular, statistically significant gender difference was shown in the luxuries characteristics as the high-quality brand for male students and the world famous brand for female students. Most respondents have experience buying luxuries. And more monthly spending money, more experience they have. Respondents' purchased items were in order of fashion goods, clothing, watches/jewelry, cosmetics/perfume. And the statistically significant differences between gender and monthly spending money were shown. Not many respondents purchased luxuries imitations, and main purchased items were fashion goods. Most of purchase motives are price over quality and economy reason. The phenomena that the respondents of relatively high levels of monthly spending money had lots of luxuries imitations shopping experiences is interesting. Female students showed higher purchase intention for luxuries and imitations than male students. There was no statistically significant difference in grade level, but was found something interesting in monthly spending money. As monthly spending money increased, the purchase intention of luxuries increased, but the purchase intention of luxuries imitations decreased. However, non-linear trend was shown in the specific allowance level. This is replicate of the luxuries imitations purchase experience. Following studies will be needed for the exact interpretation for this. This study is an exploratory and descriptive, but can provide lots of fruitful academic and practical implications in formulating luxuries marketing strategies.

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Development of Sag and Tension Sensitivity Estimation Method for Configuration Control under PPWS Erection in a Suspension Bridge (현수교 PPWS 가설중 형상관리를 위한 PPWS 새그 및 장력민감도 산정법 개발)

  • Jeong, Woon;Seo, Ju Won;Lee, Won Pyo
    • Journal of The Korean Society of Civil Engineers
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    • v.32 no.5A
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    • pp.255-266
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    • 2012
  • Main cable of a suspension bridge is the important member which shows the overall structure integrity at bridge completion. Configuration of main cable is a free hanging state at cable erection completion and is different from that at bridge completion supporting the dead loads such as hanger, girder, and so on. Accordingly, the configuration control under cable erection is considerably significant because the configuration at cable erection completion has direct influence on that at bridge completion. That is performed by sag adjustments at center, side span and tension adjustments at anchor span. The former needs the sag sensitivity which represents the control quantity of strand length corresponding to that of sag. The latter requires the tension sensitivity which shows the change of strand tension according to that of strand temperature. In this study, the fundamental equations of cable were derived with the assumption of either catenary or parabola shape, the differential-related equations using chain rule on horizontal tension were drawn from those and finally the estimation methods of the sag / tension sensitivity were proposed from both those. The nonlinear numerical analysis flow charts of sag sensitivity based on the catenary equations were proposed and the sag sensitivities grounded on the differential-related equations were compared with the results using them for various parameters of sag change. Also, considering the combinations of sag change parameters, the calculation method of the final variation for the cable sag was suggested. For the real suspension bridge under construction with PPWS method, the sag/tension sensitivity were estimated considering the construction conditions like the change of PPWS length, PPWS temperature, bridge span, etc.. We hope that this study will be a systematic guideline for the configuration control under main cable erection and improved highly by field verification in the real bridge site.

Automatic Interpretation of Epileptogenic Zones in F-18-FDG Brain PET using Artificial Neural Network (인공신경회로망을 이용한 F-18-FDG 뇌 PET의 간질원인병소 자동해석)

  • 이재성;김석기;이명철;박광석;이동수
    • Journal of Biomedical Engineering Research
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    • v.19 no.5
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    • pp.455-468
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    • 1998
  • For the objective interpretation of cerebral metabolic patterns in epilepsy patients, we developed computer-aided classifier using artificial neural network. We studied interictal brain FDG PET scans of 257 epilepsy patients who were diagnosed as normal(n=64), L TLE (n=112), or R TLE (n=81) by visual interpretation. Automatically segmented volume of interest (VOI) was used to reliably extract the features representing patterns of cerebral metabolism. All images were spatially normalized to MNI standard PET template and smoothed with 16mm FWHM Gaussian kernel using SPM96. Mean count in cerebral region was normalized. The VOls for 34 cerebral regions were previously defined on the standard template and 17 different counts of mirrored regions to hemispheric midline were extracted from spatially normalized images. A three-layer feed-forward error back-propagation neural network classifier with 7 input nodes and 3 output nodes was used. The network was trained to interpret metabolic patterns and produce identical diagnoses with those of expert viewers. The performance of the neural network was optimized by testing with 5~40 nodes in hidden layer. Randomly selected 40 images from each group were used to train the network and the remainders were used to test the learned network. The optimized neural network gave a maximum agreement rate of 80.3% with expert viewers. It used 20 hidden nodes and was trained for 1508 epochs. Also, neural network gave agreement rates of 75~80% with 10 or 30 nodes in hidden layer. We conclude that artificial neural network performed as well as human experts and could be potentially useful as clinical decision support tool for the localization of epileptogenic zones.

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The Study on the Estimation of Optimal Debt Ratio in Korean Automobile Industry (국내 자동차산업의 적정부채비율 추정을 위한 실증연구)

  • Seo, Beom;Kim, Il-Gon;Park, Ji-Hun;Im, In-Seob
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.301-308
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    • 2018
  • This study explores an analytical mathematical model designed to estimate the optimal debt ratio of the Korean automobile industry, which has a more significant effect on the national economy than that of other industries, and attempts to estimate the optimal debt ratio based on objective data. The analytical model is based on ROA and ROE which uses the debt ratio as an independent variable and employs ROS, TAT, and NFCL as the related parameters. Regarding the NFCL, the optimal debt ratio is usually defined as the debt ratio that maximizes the ROA and ROE and is calculated using analytical procedures, such as by adding an equation that considers the debt ratio and the linearity relationship to the analytical model. This is because the optimal debt ratio can be calculated reliably by making use of an estimated value within a certain range, which is derived from more than two calculations rather than a single estimation starting from one calculation formula. In this study, for the estimation of the optimal debt ratio, the ROA and ROE are expressed as a quadratic equation with the debt ratio as the independent variable. Using this analysis procedure, the optimal debt ratio obtained using the data from the Korean automobile industry over a sixteen year period, which would optimize the profitability of the Korean automobile industry, was found to be 188% of the debt ratio in the ROA and 213% of the debt ratio in the ROE. This result was obtained by overcoming the problem of the reliability of the estimation value in spite of the limitations of the logical theory of this study, and can be interpreted as meaning that maintaining a debt ratio of 188% to 213% can enhance the profitability and reduce the risks in the Korean automobile industry. Furthermore, this indicates that the existing debt ratio of the Korean automobile industry is lower than the optimal value within the estimated range. Consequently, it is necessary for corporations to change their future debt ratio policies, given that the purpose of debt ratio management is to maintain safety and increase profitability, and to take into account the characteristics of the specific industry.

Can We Hear the Shape of a Noise Source\ulcorner (소음원의 모양을 들어서 상상할 수 있을까\ulcorner)

  • Kim, Yang-Hann
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.7
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    • pp.586-603
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    • 2004
  • One of the subtle problems that make noise control difficult for engineers is “the invisibility of noise or sound.” The visual image of noise often helps to determine an appropriate means for noise control. There have been many attempts to fulfill this rather challenging objective. Theoretical or numerical means to visualize the sound field have been attempted and as a result, a great deal of progress has been accomplished, for example in the field of visualization of turbulent noise. However, most of the numerical methods are not quite ready to be applied practically to noise control issues. In the meantime, fast progress has made it possible instrumentally by using multiple microphones and fast signal processing systems, although these systems are not perfect but are useful. The state of the art system is recently available but still has many problematic issues : for example, how we can implement the visualized noise field. The constructed noise or sound picture always consists of bias and random errors, and consequently it is often difficult to determine the origin of the noise and the spatial shape of noise, as highlighted in the title. The first part of this paper introduces a brief history, which is associated with “sound visualization,” from Leonardo da Vinci's famous drawing on vortex street (Fig. 1) to modern acoustic holography and what has been accomplished by a line or surface array. The second part introduces the difficulties and the recent studies. These include de-Dopplerization and do-reverberation methods. The former is essential for visualizing a moving noise source, such as cars or trains. The latter relates to what produces noise in a room or closed space. Another mar issue associated this sound/noise visualization is whether or not Ivecan distinguish mutual dependence of noise in space : for example, we are asked to answer the question, “Can we see two birds singing or one bird with two beaks?"