• Title/Summary/Keyword: Multi-body Systems

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Design Recommendations of the Occupant Protection Systems Using Orthogonal Arrays (직교배열표를 이용한 승객보호장구의 설계)

  • 임재문;박경진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.8
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    • pp.208-215
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    • 1999
  • Using the orthogonal arrays and the occupant analysis software based on the multi-body dynamics , two interactive design algorithms are proposed to improve the initial design of the occupant protection systems. Algorithm 1 sequentially moves the narrow design space within the upper and the lower design limit. Algorithm 2 sequentially reduces the relatively wide design space. Each design algorithm is composed of two levels . The first level is to improve the characteristics of the crash performance considering the noise factors. In order to obtain the robust design, the second level reduces the variations the noise factors. In order to obtain the robust design, the second level reduces the variations due to the tolerance of the design variable. To utilize the algorithm 1, HIC(Head Injury Criterion) , 3 msec criterion value of the chest acceleration and the femur load decreased by 27.4%, 10.4% and 55.8%, respectively. To utilizer the algorithm 2 , the results decreased by 38.0%, 10.5% and 3.0% , respectively.

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Nonlinear Model-Based Disturbance Compensation for a Two-Wheeled Balancing Mobile Robot (이륜 밸런싱 로봇에 대한 비선형 모델 기반 외란보상 기법)

  • Yu, Jaerim;Kim, Yongkuk;Kwon, SangJoo
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.10
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    • pp.826-832
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    • 2016
  • A two-wheeled balancing mobile robot (TWBMR) has the characteristics of both nonlinear and underactuated system. In this paper, the disturbances acting on a TWBMR are classified into body disturbance and wheel disturbance. Additionally, we describe a nonlinear disturbance observer, which is suitable as a single input multi-output (SIMO) system for the longitudinal motion of TWBMR. Finally, we propose a reasonable disturbance compensation technique that combines the indirect reference input of equilibrium point and the direct torque compensation input. Simulations and experimental results show that the proposed disturbance compensation method is an effective way to achieve robust postural stability, specifically on inclined terrains.

Robust Design of Structural and Mechanical Systems using Concept of Allowable Load Set (허용하중집합 개념을 이용한 기계/구조 시스템의 강건 설계)

  • Kwak, Byung-Man
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.333-338
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    • 2007
  • The concept of "Allowable Load Set (ALS)" introduced by the author allows an easy understanding of load and strength characteristics of a structure in relation to its integrity under uncertainties. Two criteria of safety are introduced: A relative safety index denotes the distance to the boundary of the ALS and a normalized safety index is a distance in terms of functional value. They have been utilized in several examples, including multi-body mechanical systems such as a biomechanical system. Both formulations amount to robust designs in the sense that designs most insensitive to uncertainties are obtained in the context of newly defined safety indices, without using any input probability information.

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The submerged flexible membrane breakwaters in oblique seas

  • S.T.Kee
    • Proceedings of the Korea Water Resources Association Conference
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    • 2001.05b
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    • pp.1133-1138
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    • 2001
  • The focus of this paper is on the numerical investigation of obliquely incident wane interactions with a system composed of full submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing. The fully submerged systems allow surface and bottom clearances to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of fille second kind) tat satisfy the Helmholz governing equation. Using this computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, clearances. spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters call, if it is properly tuned to the coming waves, have good performances ill reflecting the obliquely incident waves over a tilde range of wave frequency and headings.

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Identity-Based Key Management Scheme for Smart Grid over Lattice

  • Wangke, Yu;Shuhua, Wang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.17 no.1
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    • pp.74-96
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    • 2023
  • At present, the smart grid has become one of the indispensable infrastructures in people's lives. As a commonly used communication method, wireless communication is gradually, being widely used in smart grid systems due to its convenient deployment and wide range of serious challenges to security. For the insecurity of the schemes based on large integer factorization and discrete logarithm problem in the quantum environment, an identity-based key management scheme for smart grid over lattice is proposed. To assure the communication security, through constructing intra-cluster and inter-cluster multi-hop routing secure mechanism. The time parameter and identity information are introduced in the relying phase. Through using the symmetric cryptography algorithm to encrypt improve communication efficiency. Through output the authentication information with probability, the protocol makes the private key of the certification body no relation with the distribution of authentication information. Theoretic studies and figures show that the efficiency of keys can be authenticated, so the number of attacks, including masquerade, reply and message manipulation attacks can be resisted. The new scheme can not only increase the security, but also decrease the communication energy consumption.

Modeling the Multi-Dimensional Phenomenon of Fatiguing by Assessing the Perceived Whole Body Fatigue and Local Muscle Fatigue During Squat Lifting (무릎들기 작업 시 전신피로 감지 수준과 근육 피로도를 활용한 다면적 피로현상 모델링)

  • Ahmad, Imran;Kim, Jung-Yong
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.41 no.4
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    • pp.1-8
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    • 2018
  • Whole body fatigue detection is an important phenomenon and the factors contributing to whole body fatigue can be controlled if a mathematical model is available for its assessment. This research study aims at developing a model that categorizes whole body exertion into fatigued and non-fatigued states based on physiological and perceived variables. For this purpose, logistic regression was used to categorize the fatigued and non-fatigued subject as dichotomous variable. Normalized mean power frequency of eight muscles from 25 subjects was taken as physiological variable along with the heart rate while Borg scale ratings were taken as perceived variables. The logit function was used to develop the logistic regression model. The coefficients of all the variables were found and significance level was checked. The detection accuracy of the model for fatigued and non-fatigues subjects was 83% and 95% respectively. It was observed that the mean power frequency of anterior deltoid and the Borg scale ratings of upper and lower extremities were significant in predicting the whole body fatigued when evaluated dichotomously (p < 0.05). The findings can help in better understanding of the importance of combined physiological and perceived exertion in designing the rest breaks for workers involved in squat lifting tasks in industrial as well as health sectors.

IRK vs Structural Integrators for Real-Time Applications in MBS

  • Dopico D.;Lugris U.;Gonzalez M.;Cuadrado J.
    • Journal of Mechanical Science and Technology
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    • v.19 no.spc1
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    • pp.388-394
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    • 2005
  • Recently, the authors have developed a method for real-time dynamics of multibody systems, which combines a semi-recursive formulation to derive the equations of motion in dependent relative coordinates, along with an augmented Lagrangian technique to impose the loop closure conditions. The following numerical integration procedures, which can be grouped into the so-called structural integrators, were tested : trapezoidal rule, Newmark dissipative schemes, HHT rule, and the Generalized-${\alpha}$ family. It was shown that, for large multi body systems, Newmark dissipative was the best election since, provided that the adequate parameters were chosen, excellent behavior was achieved in terms of efficiency and robustness with acceptable levels of accuracy. In the present paper, the performance of the described method in combination with another group of integrators, the Implicit Runge-Kutta family (IRK), is analyzed. The purpose is to clarify which kind of IRK algorithms can be more suitable for real-time applications, and to see whether they can be competitive with the already tested structural family of integrators. The final objective of the work is to provide some practical criteria for those interested in achieving real-time performance for large and complex multibody systems.

Systems pharmacology approaches in herbal medicine research: a brief review

  • Lee, Myunggyo;Shin, Hyejin;Park, Musun;Kim, Aeyung;Cha, Seongwon;Lee, Haeseung
    • BMB Reports
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    • v.55 no.9
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    • pp.417-428
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    • 2022
  • Herbal medicine, a multi-component treatment, has been extensively practiced for treating various symptoms and diseases. However, its molecular mechanism of action on the human body is unknown, which impedes the development and application of herbal medicine. To address this, recent studies are increasingly adopting systems pharmacology, which interprets pharmacological effects of drugs from consequences of the interaction networks that drugs might have. Most conventional network-based approaches collect associations of herb-compound, compound-target, and target-disease from individual databases, respectively, and construct an integrated network of herb-compound-target-disease to study the complex mechanisms underlying herbal treatment. More recently, rapid advances in high-throughput omics technology have led numerous studies to exploring gene expression profiles induced by herbal treatments to elicit information on direct associations between herbs and genes at the genome-wide scale. In this review, we summarize key databases and computational methods utilized in systems pharmacology for studying herbal medicine. We also highlight recent studies that identify modes of action or novel indications of herbal medicine by harnessing drug-induced transcriptome data.

Biomechanical and Physiological Comparative Analysis of the Single-Radius Knee Arthroplasty Systems and Multi-Radius Knee Arthroplasty Systems (무릎인공관절 단축범위(Single-Radius) 수술자와 다축범위(Multi-Radius) 수술자의 운동역 학적 및 운동생리학적 비교분석)

  • Jin, Young-Wan;Kwak, Yi-Sub
    • Journal of Life Science
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    • v.18 no.11
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    • pp.1532-1537
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    • 2008
  • The purpose of this study was to investigate the effect of different arthroplasty designs on knee kinematic and lower limb muscular activation for up-stair and down-stair movement. 3-D video analysis of whole body and joint kinematics and EMG analysis of quadriceps and hamstrings were conducted. One-way ANOVAs were used for statistical analyses (p=0.05). The single-radius group exhibited more arthroplasty limb quadriceps EMG and hamstring coactivation EMG than the multi-radius group. Single-radius demonstrated more abduction angular displacement and reached peak abduction earlier than the multi-radius arthroplasty limb. The single- radius the percent body fat showed similar values in the Elderly, Single and Multi-radius group among the periods, however Control group was Lowered among the periods. Single-radius group limb also increased the quadriceps muscle activation level to produce more knee extension moment to compensate for the short quadriceps moment arm. Resting metabolic rate was significantly increased in control group in the period of LI. Energy expenditure was extremely increased in all groups except control group among the periods. We can say this is the exercise effects.

A Study on the Architectural Paradigms expressed in Fashion since 1990s -Focusing on the Similarity of Spatial Construction Systems- (1990년대 이후 패션에 나타난 건축적 패러다임에 관한 연구 -공간구성 방식의 유사성을 중심으로-)

  • Yang, Hee-Young;Yang, Sook-Hi
    • Journal of the Korean Society of Costume
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    • v.56 no.7 s.107
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    • pp.85-100
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    • 2006
  • Fashion related with architectural paradigms includes concept of the space utilization beyond fashions field. Such a fashions concept is able to enlarge as a spatial system like architecture. Interface between fashion and architecture is originated in thinking of the rhizome, which understands fashions field within various relationships between environment of the city and fashion. The existing construction systems of fashion is not sufficient in fashions roles as the space that wearing changing body continuously. Consequently, accommodation of architectural paradigms in fashion depends on new recognition about function and space. Architectural paradigms expressed in fashion since 1990s was classified as follows: 1 modular system of Le Corbusier & Archigram, 2 deconstruction, 3 reconstruction, 4 nomadic architecture. Such a paradigms has been easy to combination among fashion and architecture and furniture. Deconstruction and reconstruction fashion revealed process toward completion, and reappeared architectural consideration about process of change toward incompletion. There are acknowledged formative characteristics as follows: mobility, changeability, multi-function, mutual combinative, openness, and fluidity. This study shows that fashion is essential device determined city environment construction in 21C, and revels that fashion has been highlighted as a presage of new spatial economy received architectural construction systems.