• 제목/요약/키워드: Variable transformation

검색결과 269건 처리시간 0.029초

Selecting a Transformation to Reduce Skewness

  • Yeo, In-Kwon
    • Journal of the Korean Statistical Society
    • /
    • 제30권4호
    • /
    • pp.563-571
    • /
    • 2001
  • In this paper, we study selecting a transformation so that the transformed variable is nearly symmetrically distributed. The large sample properties of an M-estimator of transformation parameter that is obtained by minimizing the integrated square of the imaginary part of the empirical characteristic function are investigated when a random sample is selected from some unspecified distribution. According to influence function calculations and Monte Carlo simulations, these estimates are less sensitive, than the normal model maximum likelihood estimates, to a few outliers.

  • PDF

이동통신 자료를 활용한 거시적 교통사고 예측 모형 개발 (Macro-Level Accident Prediction Model using Mobile Phone Data)

  • 곽호찬;송지영;이인묵;이준
    • 한국안전학회지
    • /
    • 제33권4호
    • /
    • pp.98-104
    • /
    • 2018
  • Macroscopic accident analyses have been conducted to incorporate transportation safety into long-term transportation planning. In macro-level accident prediction model, exposure variable(e.g. a settled population) have been used as fundamental explanatory variable under the concept that each trip will be subjected to a probable risk of accident. However, a settled population may be embedded error by exclusion of active population concept. The objective of this research study is to develop macro-level accident prediction model using floating population variable(concept of including a settled population and active population) collected from mobile phone data. The concept of accident prediction models is introduced utilizing exposure variable as explanatory variable in a generalized linear regression with assumption of a negative binomial error structure. The goodness of fit of model using floating population variable is compared with that of the each models using population and the number of household variables. Also, log transformation models are additionally developed to improve the goodness of fit. The results show that the log transformation model using floating population variable is useful for capturing the relationships between accident and exposure variable and generally perform better than the models using other existing exposure variables. The developed model using floating population variable can be used to guide transportation safety policy decision makers to allocate resources more efficiently for the regions(or zones) with higher risk and improve urban transportation safety in transportation planning step.

장애물 극복이 가능한 구조로봇의 주행모드 변형을 위한 PI-based Feedforward 제어 (PI-based Feedforward Control for Driving Mode Transformation of Rescue Robot capable of Obstacle Overcoming)

  • 정해관;강현석;곽윤근
    • 제어로봇시스템학회논문지
    • /
    • 제14권5호
    • /
    • pp.489-495
    • /
    • 2008
  • This paper offers a practical control scheme for driving mode transformation of a rescue robot already developed. The rescue robot, VSTR(Variable Single-Tracked Robot), has two driving modes, so can traverse untidy terrain and overcome obstacles such as stairs easily by use of timely driving mode transformation. Classical PI control scheme was used firstly for driving mode transformation, but stationary phenomenon, which might have a bad effect on the performance in real situation, came into existence. Therefore, we suggest a new controller, PI-based feedforward controller, which should be a good alternative for the problem, and compare it with other nonlinear control scheme.

현대 패션에 나타난 의복구성의 부분 변형 (The Partial Transformation of Clothing Construction in Modern Fashion)

  • 김영란
    • 한국의상디자인학회지
    • /
    • 제9권1호
    • /
    • pp.103-122
    • /
    • 2007
  • Fashion have been expressed by a face through various a period, social change, and various culture changing. Human expresses as "Transformation" by applying these needs of changing to the fashion. A origin tribe expressed its own self by using direct body transformation and extreme decorations in the past. However, human express creative and esthetic desire based on shape, material, and transformation method in the present time characteristics of the body. Exceptional transformation breaking a existing fixed idea appeared frequently due to dissolution through transformation which is positive expression method in the fashion from 20th century. As a results, followings are obtained in this study. First, human body transforms by using a tool or intermediation in investigation of aesthetic meaning for human body. The object, Transformation, is stably transformed by disintegration, distortion, exaggeration and simplification reduction, as design's sensitivity. Second, transformation from relation of clothing composition is expressed by extension, reduction, simplification, and dissolution. In transformation from original tribe's sensitivity, past decorative desire lead to transformation of human body. To give variable change from past to present fashion, external formative will is introduced. Then, extreme expression is made by direct transformation of clothing type. It seems to be accomplished that human body's expression method is continuously changed into extension, exaggeration, reduction, and dissolution from transformation method as described before. Transformation of modem fashion is expression method by creative supervision. Extreme transformation substituted body's each part is based on immanent play and representative satisfaction. Through these transformation, it is judged that variety of creative type is achieved.

  • PDF

구조 로봇에 적합한 가변형 단일 트랙 메커니즘 (Variable Geometry Single-Tracked Mechanism for Rescue Robot)

  • 임성균;박동일;곽윤근
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2004년도 추계학술대회
    • /
    • pp.720-724
    • /
    • 2004
  • This paper introduces a new type of driving mechanism for rescue robot that has a variable geometry single-track which satisfies the pre-conditions of rescue robot. This mechanism is a symmetric configuration that has dual directions and prepares against overturn. By using transformation, it can reduce the energy consumption in steering and rotating. And also it maximizes the ability to overcome obstacles, like steps. It is designed to make the size of robot compact and to have the low center of gravity in driving on steps. Finally, we optimized the design variables of components determining the shape of reverse-trapezoid frame to enhance the adaptability to 4 phases of climbing steps.

  • PDF

Expression of a Functional Anti-Cucumber Mosaic Virus Single-Chain Variable Fragment Antibody in Tobacco Plants (Nacotiana tabacum)

  • Heng Chua Kek;Khalid Norzulaani;Othman Retina Yasmin
    • Journal of Plant Biotechnology
    • /
    • 제8권1호
    • /
    • pp.9-14
    • /
    • 2006
  • As an alternative method to produce low cost reagents for immunodiagnosis and protect the plants from viral disease, a gene encoding a single chain variable fragment(scFv) recombinant antibody targeted to the coat protein of cucumber mosaic virus (CMV) was expressed in Nacotiana tabacum. The source of the scFv recombinant antibody gene was from spleen tissue of an immunized mouse. The gene was initially cloned into the pCANTAB5E phagemid and expressed in E. coli. In the following study, the antibody gene was subcloned into the plant expression vector, pCAMBIA-1301 and introduced into tobacco leaf tissue via Agrobacterium tumefacients mediated transformation. After transformation, 56 out of 58 plants were shown to carry the desired anti-CMV scFv gene by PCR analysis. Overall, only 12.5% of the 56 putative transgenic plants were found to express the antibody to a detectable level.

디지털 제어기법에 의한 체인드시스템의 제어 (Chained systems control using digital state steering)

  • 남택근;노영오;안병원;허광석
    • 한국마린엔지니어링학회:학술대회논문집
    • /
    • 한국마린엔지니어링학회 2005년도 전기학술대회논문집
    • /
    • pp.287-292
    • /
    • 2005
  • In this paper, a state steering strategy using digital control method for chained system is presented. The chained system can be derived from the velocity or acceleration constraints that cannot be integrable. Especially, the chained system derived from an acceleration constraints is called the high order chained system. Such a system classified as a nonholonomic systems and cannot be controlled to its equilibrium points by continuous and time-invariant controller. Therefore discontinuous and time varying controller should be applied to control nonholonomic system. Using variable transformation, two sub system can be obtained from the chained or high order chained system. Deadbeat control and iterative state steering methods are proposed to control the systems that obtained from the variable transformation. Simulation results are given to show the effectiveness of the proposed control scheme.

  • PDF

Moment-Based Density Approximation Algorithm for Symmetric Distributions

  • Ha, Hyung-Tae
    • Communications for Statistical Applications and Methods
    • /
    • 제14권3호
    • /
    • pp.583-592
    • /
    • 2007
  • Given the moments of a symmetric random variable, its density and distribution functions can be accurately approximated by making use of the algorithm proposed in this paper. This algorithm is specially designed for approximating symmetric distributions and comprises of four phases. This approach is essentially based on the transformation of variable technique and moment-based density approximants expressed in terms of the product of an appropriate initial approximant and a polynomial adjustment. Probabilistic quantities such as percentage points and percentiles can also be accurately determined from approximation of the corresponding distribution functions. This algorithm is not only conceptually simple but also easy to implement. As illustrated by the first two numerical examples, the density functions so obtained are in good agreement with the exact values. Moreover, the proposed approximation algorithm can provide the more accurate quantities than direct approximation as shown in the last example.

의탄성 형상기억합금에 대한 현상학적 구성모델 (A Phenomenological Constitutive Model for Pseudoelastic Shape Memory Alloy)

  • 호광수
    • 소성∙가공
    • /
    • 제19권8호
    • /
    • pp.468-473
    • /
    • 2010
  • Shape memory alloys (SMAs) have the ability to recover their original shape upon thermo-mechanical loading even after large inelastic deformation. The unique feature is known as pseudoelasticity and shape memory effect caused by the crystalline structural transformation between two solid-state phases called austenite and martensite. To support the engineering application, a number of constitutive models, which can be formally classified into either micromechanics-based or phenomenological model, have been developed. Most of the constitutive models include a kinetic law governing the crystallographic transformation. The present work presents a one-dimensional, phenomenological constitutive model for SMAs in the context of the unified viscoplasticity theory. The proposed model does not incorporate the complex mechanisms of phase transformation. Instead, the effects induced by the transformation are depicted through the growth law for the back stress that is an internal state variable of the model.

Utkin 정리의 다입력 불확실 선형 시스템에 대한 증명 (A Poof of Utkin's Theorem for a MI Uncertain Linear Case)

  • 이정훈
    • 전기학회논문지
    • /
    • 제59권9호
    • /
    • pp.1680-1685
    • /
    • 2010
  • In this note, a proof of Utkin's theorem is presented for a MI(Multi Input) uncertain linear case. The invariance theorem with respect to the two transformation methods so called the two diagonalization methods are proved clearly and comparatively for MI uncertain linear systems. With respect to the sliding surface transformation and the control input transformation, the equation of the sliding mode i.e., the sliding surface is invariant. Both control inputs have the same gains. By means of the two transformation methods the same results can be obtained. Through an illustrative example and simulation study, the usefulness of the main results is verified.