• Journal of the Korean Data and Information Science Society
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• 제23권4호
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• pp.797-805
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• 2012

Many circular distributions are known to be not only asymmetric but also bimodal. Hidden truncation method of generating asymmetric distribution is applied to a bivariate circular distribution to generate an asymmetric circular distribution. While many other existing asymmetric circular distributions can only model an asymmetric data, this new circular model has great flexibility in terms of asymmetry and bi-modality. Some properties of the new model, such as the trigonometric moment generating function, and asymptotic inference about the truncation parameter are presented. Simulation and real data examples are provided at the end to demonstrate the utility of the novel distribution.

• 한국통신학회논문지
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• 제18권4호
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• pp.457-467
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• 1993

랜덤매질을 통과한 광파에 대한 중요한 통계적인 양 중의 하나는 광도의 확률분포이다. 현상학적 모델로부터 여러가지 분포함수들이 제안되었다. 본 논문에서는 컴퓨터 시뮬레이션에 의해 광도데이타를 얻고, 모멘트법, 히스토그램법 및 $x^2$-테스트에 의해 제안된 분포함수들을 시뮬레이션 데이터와 비교함으로써 각 분포함수들의 타당성을 조사하고자 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.79-83
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• 2005

SEA is a useful tool to predict noise and vibration response in high frequency region but has a weak point not to be able to express modal behavior in low frequency region. For a structure with middle subsystem having relatively higher modal density than excited subsystem and receiving subsystem, we studied the possibility that the modal behavior of receiving subsystem can express by considering finite mobility of excited subsystem. For a simply three-coupled beams which is chosen for feasibility study, the response of receiving beam was investigated with varying the length & area moment of inertia of middle beam. In case that the middle beam has relatively higher modal density than exciting beam, the application to finite mobility of excited beam led to express modal behavior of receiving beam relatively well.

• 대한원격탐사학회지
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• 제24권3호
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• pp.267-272
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• 2008

Tree species-specific estimates with spacebome high-resolution imagery improve estimation of forest biomass which is needed to predict the long term planning for the sustainable forest management(SFM). This paper is a contribution to develop crown distinguishing coniferous species, Pinus densiflora and Pinus koraiensis, from QuickBird imagery. The proposed feature analysis derived from shape parameters and first and second-order statistical texture features of the same test area were compared for the two species separation and delineation. As expected, initial studies have shown that both formfactor and compactness shape parameters provided the successful differentiating method between the pine species within the compartment for single crown identification from spaceborne high resolution imagery. Another result revealed that the selected texture parameters - the mean, variance, angular second moment(ASM) - in the infrared band image could produce good subset combination of texture features for representing detailed tree crown outline.

• Asia pacific journal of information systems
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• 제31권4호
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• pp.633-673
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• 2021

Due to the differences between and distinct consumer perceptions of domestic and cross-border e-commerce (CBEC), e-consumer misconduct, which we call "cunning behavior," has emerged. This study examines cunning behavior in CBEC and compares e-consumer perceptions about environmental factors and their own personal traits using a vignette experiment and survey. The vignettes of this study were developed for three situations: illegal, deviant, and unethical behavior. Drawing on vignettes, we collected survey data and then examined the research model using the analysis of moment structure statistical tool. The results show that perceived benefit and past experience with CBEC are strong triggers for cunning behavior, while the ability to exercise self-control restrains this behavior. This study provides an understanding of why cunning behavior occurs in the CBEC context and describes different cunning behavior types.

• 대한의용생체공학회:의공학회지
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• 제37권1호
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• pp.21-30
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• 2016

Weibull distribution with two parameters, shape (k) and scale (s) parameters are used to model the fatigue failure analysis due to periodic vortex shedding of the synovial fluid in knee joints. In order to determine the later parameter, a suitable statistical model is required for velocity distribution of synovial fluid flow. Hence, wide applicability of Weibull distribution in life testing and reliability analysis can be applied to describe the probability distribution of synovial fluid flow velocity. In this work, comparisons of three most widely used methods for estimating Weibull parameters are carried out; i.e. the least square estimation method (LSEM), maximum likelihood estimator (MLE) and the method of moment (MOM), to study fatigue failure of bone joint due to periodic vortex shedding of synovial fluid. The performances of these methods are compared through the analysis of computer generated synovial fluidflow velocity distribution in the physiological range. Significant values for the (k) and (s) parameters are obtained by comparing these methods. The criterions such as root mean square error (RMSE), coefficient of determination ($R^2$), maximum error between the cumulative distribution functions (CDFs) or Kolmogorov-Smirnov (K-S) and the chi square tests are used for the comparison of the suitability of these methods. The results show that maximum likelihood method performs well for most of the cases studied and hence recommended.

• 한국운동역학회지
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• 제25권1호
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• pp.29-37
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• 2015

Objective : The purpose of this study was to investigate the biomechanical properties of shock absorption strategy and postural stability during the drop landing for each types. Methods : The motions were captured with Vicon Motion Capture System, with the fourteen infra-red cameras (100Hz) and synchronized with GRF(ground reaction force) data(1000Hz). Ten male soccer players performed a drop landing with single-leg and bi-legs on the 30cm height box. Dependent variables were the CoM trajectory and the Joint Moment. Statistical computations were performed using the paired t-test and ANOVA with Turkey HSD as post-hoc. Results : The dominant leg was confirmed to show a significant difference between the left leg and right leg as the inverted pendulum model during Drop Landing(Phase 1 & Phase 2). One-leg drop landing type had the higher CoM displacement, the peak of joint moment with the shock absorption than Bi-leg landing type. As a lower extremity joint kinetics analysis, the knee joint showed a function of shock absorption in the anterior-posterior, and the hip joint showed a function of the stability and shock absorption in the medial-lateral directions. Conclusion : These findings indicate that the instant equilibrium of posture balance(phase 1) was assessed by the passive phase as Class 1 leverage on the effect of the stability of shock absorption(phase 2) assessed by the active phase on the effect of Class 2 leverage. Application : This study shows that the cause of musculo-skeletal injuries estimated to be focused on the passive phase of landing and this findings could help the prevention of lower damage from loads involving landing related to the game of sports.

• Journal of Nutrition and Health
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• 제37권9호
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• pp.794-800
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• 2004

Deer Antler has been known for its traditional oriental medicinal properties and has been widely used to promote growth, boost immune function, treat blood loss and chronic joint pain. Recent study showed imported (New Zealand) Deer Antler was beneficial in reducing the side effects of cancer treatments. However, there was no intervention study conducted on the effect of Korean Deer Antler on reducing the oxidative stress to patients with diabetes. One of the sensitive ways to measure endogenous oxidative stress is by measuring cellular DNA damage using single cell gel electrophoresis (COMET assay). This study was conducted to investigate the possible beneficial effect of commercial Deer Antler drink (provided by Chung-yang Deer Farm) on lymphocyte DNA damage and blood glucose of diabetic patients. Ten patients (4 men, 6 women) participated in the study and consumed 2 pouches of Deer Antler drink every day for 20 days. Blood was collected on the morning before and after the intervention for lymphocyte isolation and blood glucose analysis. Both systolic and diastolic blood pressure showed a tendency to decrease but did not reach statistical significance after the trial. Blood glucose level was not affected by the supplementation. After the intervention, over 50% reduction were noted in the cellular DNA damage, expressed as tail length (TL) and tail moment (TM: tail length ${\times}$ percent tail DNA) . Although we did not obtain beneficial effect on lowering blood glucose levels in the patients, this results suggest that Deer Antler may initially act in protecting endogenous DNA damage in short-term experiment.

• 한국산학기술학회논문지
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• 제11권10호
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• pp.3833-3838
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• 2010

뇌파는 시시각각 변하는 뇌 상태를 가장 효과적으로 측정하는 수단이다. 뇌는 신진대사의 근간인 호르몬과 직접적인 관계가 있으므로 뇌파와 호르몬간의 영향관계를 규명할 필요가 있다. 본 연구는 뇌파만으로 신진대사와 관련된 정보의 산출이 가능함을 밝히는 연구를 수행하였다. 주요 연구변수는, 2007년 3월 3일부터 5월 28일까지 측정한, 직장인 여성들의 스트레스 정보인 뇌파 항스트레스 지수와 코티졸 호르몬 농도이다. 이들 간의 영향관계를 밝히고자, 뇌파훈련 전후에 대한 t검증, 상관분석, 회귀분석을 주된 연구방법으로 수행하였으며, 다음과 같은 결과가 도출되었다. 첫째, 뇌파훈련에 의해 변수들의 변화에 대한 유의한 차이가 검증되었다. 둘째, 변수들 간에 상관성이 존재함을 규명하였다. 마지막으로 회귀분석에서, 변수들 간에 영향력이 있는 것으로 파악되었다. 그러므로 뇌파분석만으로도 호르몬 분석수준의 스트레스 정보를 제공할 수 있다는 결론에 도달하였다.

• Structural Engineering and Mechanics
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• 제13권4호
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• pp.369-385
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• 2002

Ductility capacity is comprehensively studied for steel moment-resisting frames. Local, story and global ductility are being considered. An appropriate measure of global ductility is suggested. A time domain nonlinear seismic response algorithm is used to evaluate several definitions of ductility. It is observed that for one-story structures, resembling a single degree of freedom (SDOF) system, all definitions of global ductility seem to give reasonable values. However, for complex structures it may give unreasonable values. It indicates that using SDOF systems to estimate the ductility capacity may be a very crude approximation. For multi degree of freedom (MDOF) systems some definitions may not be appropriate, even though they are used in the profession. Results also indicate that the structural global ductility of 4, commonly used for moment-resisting steel frames, cannot be justified based on this study. The ductility of MDOF structural systems and the corresponding equivalent SDOF systems is studied. The global ductility values are very different for the two representations. The ductility reduction factor $F_{\mu}$ is also estimated. For a given frame, the values of the $F_{\mu}$ parameter significantly vary from one earthquake to another, even though the maximum deformation in terms of the interstory displacement is roughly the same for all earthquakes. This is because the $F_{\mu}$ values depend on the amount of dissipated energy, which in turn depends on the plastic mechanism, formed in the frames as well as on the loading, unloading and reloading process at plastic hinges. Based on the results of this study, the Newmark and Hall procedure to relate the ductility reduction factor and the ductility parameter cannot be justified. The reason for this is that SDOF systems were used to model real frames in these studies. Higher mode effects were neglected and energy dissipation was not explicitly considered. In addition, it is not possible to observe the formation of a collapse mechanism in the equivalent SDOF systems. Therefore, the ductility parameter and the force reduction factor should be estimated by using the MDOF representation.