• Title/Summary/Keyword: conditional mean

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Correlation of Primary Spontaneous Pneumothorax and Air Pollution in Adolescents

  • Gu, Byung Mo;Ko, Ho Hyun;Ra, Yong Joon;Lee, Hee Sung;Kim, Hyoung Soo;Lee, Hong Kyu
    • Journal of Chest Surgery
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    • v.54 no.1
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    • pp.53-58
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    • 2021
  • Background: We aimed to investigate the characteristics of primary spontaneous pneumothorax (PSP) in adolescents and to analyze the relationship between the occurrence of PSP and air pollutants. Methods: Data pertaining to age, sex, body mass index, smoking status, initial pneumothorax volume, presence of bullae, treatment methods, and city of residence were retrospectively obtained from January 2010 to December 2014. We investigated the association between short-term exposure to air pollutants (SO2, NO2, O3, CO, and PM10) and the occurrence of PSP using a case-crossover design with conditional logistic regression. Results: We collected information from 598 patients who were admitted for PSP, with a mean follow-up duration of 62.9 months. The majority (91.1%) of the patients were male. In the case-crossover design, conditional logistic regression showed that no air pollutant was associated with the occurrence of pneumothorax. The results were consistent across all city subgroups (Anyang, Gunpo, Uiwang, and Gwacheon). Conclusion: In our study, the incidence rate of pneumothorax was 153.8 per 100,000 person-years in male adolescents and 16.7 per 100,000 person-years in female adolescents. The case-crossover design showed that PSP in adolescents is unlikely to be related to air pollution.

Clothing expenditure, and mediation effect of self-efficacy and moderating effect of disability acceptance in the association between dependency on others and happiness among visually impaired people - Moderated mediating model - (시각장애인의 의복비 지출 현황 조사 및 타인 의존도와 행복의 관계에 미치는 자기효능의 매개효과와 장애 수용의 조절효과 검증 - 조절된 매개모형 분석 -)

  • Minsun, Lee;Hae Rim, Park;Ho Jung, Yang
    • The Research Journal of the Costume Culture
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    • v.30 no.6
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    • pp.842-860
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    • 2022
  • There has been growing attention on the well-being of people with disabilities. The purpose of this study was twofold: (1) to investigate the associations between individuals' socio-demographic and psychological characteristics and clothing expenditure, and (2) to examine the moderated mediation effect of self-efficacy and acceptance of disability on the association between dependency on others and happiness among people with visual impairment. This study was based on secondary analysis of data from the second wave of the 6th Panel Survey of Employment for the Disabled collected by the Employment Development Institute. The results of this study showed that average monthly expenditure on clothing was positively associated with self-efficacy, happiness, and acceptance of disability, while being negatively associated with dependency on others. The results also confirmed that self-efficacy mediated the association between dependency on others and happiness. A conditional direct effect of dependency on others on happiness was found, in which negative associations were significant among people with visual impairment who had low and mean levels of acceptance of disability (but not high levels). In addition, there was a significant conditional indirect effect, in which the indirect and negative effect of dependency on others on happiness via self-efficacy was significant for those with low and average levels of acceptance of disability. These findings support the importance of enhancing the independence and acceptance of disability among people with visual impairment, which ultimately contributes to their happiness.

(Suboptimal Detection Thresholds for Tracking in Clutter) (클러터 환경에서의 표적 추적을 위한 준최적의 검출 문턱값)

  • Jeong, Yeong-Heon;Sin, Han-Seop
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.39 no.2
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    • pp.176-181
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    • 2002
  • In this paper, we consider the optimal control of detection threshold to minimize the conditional expectation of mean-square state estimation error for a probabilistic data association (PDA) filter. Earlier works on this problem involved the cumbersome graphical optimization algorithm or time-consuming numerical optimization algorithm. Using the numerical approximation of information reduction factor, we obtained the suboptimal detection threshold in a closed-form. This results are very useful for real- time implementation.

Determination Conversion Weight of Convertible Bonds Using Mean/Value-at-Risk Optimization Models (평균/VaR 최적화 모형에 의한 전환사채 주식전환 비중 결정)

  • Park, Koohyun
    • Korean Management Science Review
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    • v.30 no.3
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    • pp.55-70
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    • 2013
  • In this study we suggested two optimization models to determine conversion weight of convertible bonds. The problem of this study is same as that of Park and Shim [1]. But this study used Value-at-Risk (VaR) for risk measurement instead of CVaR, Conditional-Value-at-Risk. In comparison with conventional Markowitz portfolio models, which use the variance of return, our models used VaR. In 1996, Basel Committee on Banking Supervision recommended VaR for portfolio risk measurement. But there are difficulties in solving optimization models including VaR. Benati and Rizzi [5] proved NP-hardness of general portfolio optimization problems including VaR. We adopted their approach. But we developed efficient algorithms with time complexity O(nlogn) or less for our models. We applied examples of our models to the convertible bond issued by a semiconductor company Hynix.

Numerical Study on Turbulent Nonpremixed Pilot Stabilized Flame using the Transported Probability Density Function Model (수송확률밀도함수 모델을 이용한 난류비예혼합 파일럿 안정화 화염장 해석)

  • Lee, Jeong-Won;Kim, Yong-Mo
    • Journal of the Korean Society of Combustion
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    • v.15 no.4
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    • pp.15-21
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    • 2010
  • The transported probability density function(PDF) model has been applied to simulate the turbulent nonpremixed piloted jet flame. To realistically account for the mixture fraction PDF informations on the turbulent non-premixed jet flame, the present Lagrangian PDF transport approach is based on the joint velocity-composition-turbulence frequency PDF formulation. The fluctuating velocity of stochastic fields is modeled by simplified Langevin model(SLM), turbulence frequency of stochastic fields is modeled by Jayesh-Pope model and effects of molecular diffusion are represented by the interaction by exchange with the mean (IEM) mixing model. To validate the present approach, the numerical results obtained by the joint velocity-composition-turbulence frequency PDF model are compared with experimental data in terms of the unconditional and conditional means of mixture fraction, temperature and species and PDFs.

Performance Analysis of Noncoherent CDMA Systems Using Adaptive Array Antennas (Noncoherent CDMA 시스템에서의 적응 배열 안테나 성능 분석)

  • 박재홍;최동민정하송박한규
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.42-45
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    • 1998
  • Adaptive array antenas have emerged as a useful technique to enhance the cell capacity of mobile communications. In this research, to analyze the noncoherent CDMA systems employing adaptive array antennas, we modeled the transmitting signal of CDMA systems using M-ary orthogonal modulation. And we induced the conditional probability density function about the decision variable, the output of 2D-RAKE receiver and mean symbol error prabability through statistical analysis about MAI(Multiple Access Interference), SI(Self Interference) and Noise. Also, we analyzed the charateristics of adaptive array antenna for noncoherent CDMA systems using M-ary orthogonal modulation according to the distance between the array elements, doppler frequency and AOS(Angle of Spread).

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Bayesian curve-fitting with radial basis functions under functional measurement error model

  • Hwang, Jinseub;Kim, Dal Ho
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.3
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    • pp.749-754
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    • 2015
  • This article presents Bayesian approach to regression splines with knots on a grid of equally spaced sample quantiles of the independent variables under functional measurement error model.We consider small area model by using penalized splines of non-linear pattern. Specifically, in a basis functions of the regression spline, we use radial basis functions. To fit the model and estimate parameters we suggest a hierarchical Bayesian framework using Markov Chain Monte Carlo methodology. Furthermore, we illustrate the method in an application data. We check the convergence by a potential scale reduction factor and we use the posterior predictive p-value and the mean logarithmic conditional predictive ordinate to compar models.

Seismic Response Estimation and System Identification of Test Steel Structure Using Approximate Nonlinear Filter (비선형 근사필터에 강구조시험체의 지진응답추정 및 동특성식별)

  • 배기환;김두영
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.2
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    • pp.67-72
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    • 2001
  • 대상으로 하는 시스템의 입출력신호에 근거하여, 시스템의 수학적 모델을 결정하는 것을 총칭하여 시스템식별이라 한다. 본 논문에서는 지진응답 관측치를 입출력신호로 하여 조건부대치를 최적치로 판단하는 비선형근사필터법을 사용한 건축구조물의 지진응답추정 및 파라미터식별에 관하여 논한다. 비선형근사필터법에 의한 건축구조물식별의 유효성의 적용성을 판단하기 위해, 진동대를 사용하여 강구조시험체의 진동실험을 행하고 결과적으로 얻어진 시험체의 수학적 모델에 대한 지진응답 수치해석결과와 진동실험에서의 관측기록을 비교하여 본 식별법의 타당성을 보인다.

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GEOSTATISTICAL UNCERTAINTY ANALYSIS IN SEDIMENT GRAIN SIZE MAPPING WITH HIGH-RESOLUTION REMOTE SENSING IMAGERY

  • Park, No-Wook;Chi, Kwang-Hoon
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.225-228
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    • 2007
  • This paper presents a geostatistical methodology to model local uncertainty in spatial estimation of sediment grain size with high-resolution remote sensing imagery. Within a multi-Gaussian framework, the IKONOS imagery is used as local means both to estimate the grain size values and to model local uncertainty at unsample locations. A conditional cumulative distribution function (ccdf) at any locations is defined by mean and variance values which can be estimated by multi-Gaussian kriging with local means. Two ccdf statistics including condition variance and interquartile range are used here as measures of local uncertainty and are compared through a cross validation analysis. In addition to local uncertainty measures, the probabilities of not exceeding or exceeding any grain size value at any locations are retrieved and mapped from the local ccdf models. A case study of Baramarae beach, Korea is carried out to illustrate the potential of geostatistical uncertainty modeling.

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A Systematic Design of Automatic Fuzzy Rule Generation for Dynamic System

  • Kang, Hoon;Kim, Young-Ho;Jeon, Hong-Tae
    • Journal of the Korean Institute of Intelligent Systems
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    • v.2 no.3
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    • pp.29-39
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    • 1992
  • We investigate a systematic design procedure of automatic rule generation of fuzzy logic based controllers for highly nonlinear dynamic systems such as an engine dynamic modle. By "automatic rule generation" we mean autonomous clustering or collection of such meaningful transitional relations from one conditional subspace to another. During the design procedure, we also consider optimaly control strategies such as minimum squared error, near minimum time, minimum energy or combined performance critiera. Fuzzy feedback control systems designed by our method have the properties of closed-loop stability, robustness under parameter variabitions, and a certain degree of optimality. Most of all, the main advantage of the proposed approach is that reliability can be potentially increased even if a large grain of uncertainty is involved within the control system under consideration. A numerical example is shown in which we apply our strategic fuzzy controller dwsign to a highly nonlinear model of engine idling speed control.d control.

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