197,859 research outputs found
Models for the Dynamic Simulation of Tank Track Components
No full textThis project has been sponsored by QinetiQ Limited (QinetiQ); whose aim it is to
model the dynamics of a prototype high-speed military tracked vehicle. Specifically
their objective is to describe the mechanism by which force inputs are transmitted
from the ground to the vehicle’s hull.
Many track running gear components are steel and can be modelled as simple lumped
masses or as linear springs without internal damping. These present no difficulty to
the modeller. However tracked vehicle running gear also has nonlinear components
that require more detailed descriptions. Models for two rubber components, the road
wheel tyre and track link bush, and a model for the suspensions rotary damper, are
developed here. These three components all have highly nonlinear dynamic responses.
Rubber component nonlinearities are caused by the materials nonlinear elastic and
viscoelastic characteristics. Stiffness is amplitude dependent and the material exhibits
a significant amount of internal damping, which is predominantly Coulombic in
nature but also relaxes overtime. In this work, a novel method for measuring the
elastic and viscoelastic response of Carbon Black Filled Natural Rubber components
has been devised and a ‘general purpose’ mathematical model developed that
describes the materials response and is suited to use in multibody dynamic analysis
software.
The vehicle’s suspension rotary damper model describes three viscous flow regimes
(laminar, turbulent and pressure relief), as a continuous curved response that relates
angular velocity to damping torque. Hysteresis due to the compression of entrapped
gas, compliance of the dampers structure and compression of damper oil is described by a single non-parametric equation. Friction is considered negligible and is omitted
from the model.
All components are modelled using MSC.ADAMS TM multibody dynamic analysis
software. The models are shown to be easily implemented and computationally
robust. QinetiQ’s requirement for ‘practical’ track running gear component models
has been met
BLGAN: Bayesian Learning and Genetic Algorithm for Supporting Negotiation With Incomplete Information
No full textAutomated negotiation provides a means for resolving
differences among interacting agents. For negotiation with
complete information, this paper provides mathematical proofs
to show that an agent’s optimal strategy can be computed using
its opponent’s reserve price (RP) and deadline. The impetus of
this work is using the synergy of Bayesian learning (BL) and
genetic algorithm (GA) to determine an agent’s optimal strategy
in negotiation (N) with incomplete information. BLGAN adopts:
1) BL and a deadline-estimation process for estimating an opponent’s
RP and deadline and 2) GA for generating a proposal
at each negotiation round. Learning the RP and deadline of an
opponent enables the GA in BLGAN to reduce the size of its search
space (SP) by adaptively focusing its search on a specific region
in the space of all possible proposals. SP is dynamically defined
as a region around an agent’s proposal P at each negotiation
round. P is generated using the agent’s optimal strategy determined
using its estimations of its opponent’s RP and deadline.
Hence, the GA in BLGAN is more likely to generate proposals
that are closer to the proposal generated by the optimal strategy.
Using GA to search around a proposal generated by its current
strategy, an agent in BLGAN compensates for possible errors in
estimating its opponent’s RP and deadline. Empirical results show
that agents adopting BLGAN reached agreements successfully,
and achieved: 1) higher utilities and better combined negotiation
outcomes (CNOs) than agents that only adopt GA to generate their
proposals, 2) higher utilities than agents that adopt BL to learn
only RP, and 3) higher utilities and better CNOs than agents that
do not learn their opponents’ RPs and deadlines
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Physical dance performance: An investigation into the development of a performance technique based on the integration of certain Korean dance technique and contemporary Western styles of dance and physical theatre
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 04/10/2001.This development of a performer practice that integrates elements of traditional Korean dance technique and Western forms of physical theatre and contemporary dance is based on an approach to internal understanding and external execution. Central to the work is the concept of body energy, or Ki. This ancient Eastern term is translated into a contemporary practice that enables a performer to engage mental and physical training. Breath and the use of breath in performing are the principal means of achieving this level of engagement
Evolving Fuzzy Rules for Relaxed-Criteria Negotiation
No full textIn the literature on automated negotiation, very few negotiation agents are designed with the flexibility to slightly relax their negotiation criteria to reach a consensus more rapidly and with more certainty. Furthermore, these relaxed-criteria negotiation agents were not equipped with the ability to enhance their performance by learning and evolving their relaxed-criteria negotiation rules. The impetus of this work is designing market-driven negotiation agents (MDAs) that not only have the flexibility of relaxing bargaining criteria using fuzzy rules, but can also evolve their structures by learning new relaxed-criteria fuzzy rules to improve their negotiation outcomes as they participate in negotiations in more e-markets. To this end, an evolutionary algorithm for adapting and evolving relaxed-criteria fuzzy rules was developed. Implementing the idea in a testbed, two kinds of experiments for evaluating and comparing EvEMDAs (MDAs with relaxed-criteria rules that are evolved using the evolutionary algorithm) and EMDAs (MDAs with relaxed-criteria rules that are manually constructed) were carried out through stochastic simulations. Empirical results show that: 1) EvEMDAs generally outperformed EMDAs in different types of e-markets and 2) the negotiation outcomes of EvEMDAs generally improved as they negotiated in more e-markets
Gabriel Vahanian, Hananim gwa utoGa : gyo hoe wa teknik. Sung Kwang Publishing C°, Seoul 1991
No full textVahanian Gabriel. Gabriel Vahanian, Hananim gwa utoGa : gyo hoe wa teknik. Sung Kwang Publishing C°, Seoul 1991. In: Revue d'histoire et de philosophie religieuses, 72e année n°2, Avril-juin 1992. p. 226
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Grid Commerce, Market-Driven G-Negotiation, and Grid Resource Management
No full textAlthough the management of resources is essential
for realizing a computational grid, providing an efficient resource
allocation mechanism is a complex undertaking. Since Grid
providers and consumers may be independent bodies, negotiation
among them is necessary. The contribution of this paper
is showing that market-driven agents (MDAs) are appropriate
tools for Grid resource negotiation.MDAs are e-negotiation agents
designed with the flexibility of: 1) making adjustable amounts of
concession taking into account market rivalry, outside options,
and time preferences and 2) relaxing bargaining terms in the
face of intense pressure. A heterogeneous testbed consisting of
several types of e-negotiation agents to simulate a Grid computing
environment was developed. It compares the performance
of MDAs against other e-negotiation agents (e.g., Kasbah) in a
Grid-commerce environment. Empirical results show that MDAs
generally achieve: 1) higher budget efficiencies in many market
situations than other e-negotiation agents in the testbed and
2) higher success rates in acquiring Grid resources under high
Grid loadings
Kim, Kwang-Kyoun
No full text학위논문(박사)----아주대학교 일반대학원 :의학과,2008. 2목 적: 유한요소 해석을 이용하여 슬관절의 경골 관절면에서 거리에 따른 절단면의 기계적 강도 차이를 분석하고 이를 슬관절 인공관절 치환술 시에 고려하고자 한다.
재료 및 방법: 슬관절 인공관절 치환술을 위해 내원한 퇴행성 관절염 환자에서 시행한 20 례의 슬관절 전산화 단층 촬영 영상을 이용하였고 각 전산화 단층 영상을 자동 메쉬 형성(automatic mesh generation) 소프트웨어 BIONIX™ (CANTIBio. Co, Suwon, Korea) 프로그램을 이용하여 8절점 정육방형 요소(8-node hexahedron element)로 모델을 생성하였다. 유한요소 모델은 근위 경골 외과측 관절면에서 6mm, 8mm, 10mm, 12mm, 15mm, 18mm씩 절단하여 20개의 모델당 각 6개의 유한요소 모델을 만들었다. BIONIX™ 소프트웨어에서 생성된 8절점 정육방형 요소는 HyperMeshTM(Altair Engineering. Inc, Seattle, U.S.A) 소프트웨어를 사용하여 1%의 변형률(strain rate)을 가하여 경계 조건을 적용했다. 유한요소 해석은 상용 소프트 웨어인 ANSYS 9.0 (ANSYS. Inc, Orlando, U.S.A)을 이용하여 최대 응력(σu, Ultimate stress)을 구하였다.
결과: 전체 최대 응력의 평균은 810.18 Mpa 이었고 각 절단면에서 최대 응력의 평균은 6 mm에서 906.84 MPa, 8 mm에서 877.22 MPa, 10 mm에서 895.93 MPa, 12 mm에서 852.70 MPa, 15 mm에서 742.90 MPa, 18 mm에서 585.51 MPa로 관절면으로부터 절제 거리가 증가할 수 록 절단면의 평균 최대응력은 감소하는 경향을 보였다.
전체 평균 최대 응력에 대해 6 mm와 비교해서 8 mm, 10 mm, 12 mm에서의 최대 응력의 변화는 3.58%, 1.30%, 5.66%로 의미 있는 감소는 없었으나 15 mm일 때는 20.24% 그리고 18 mm일 때는 39.62%가 감소하였다. 6 mm 절제 시 평균 최대 응력에 대한 절제 거리에 대한 최대 응력의 변화는 8 mm에서 3.20% 10 mm에서 1.21% 12 mm에서 5.96% 15 mm에서는 18.09% 18 mm에서는 35.40%였다. 각 절제 거리에 따른 비교 및 연속된 절제 거리간의 최대 응력변화의 통계적 의미는 paired t-test를 이용하였다. 6 mm 절단면의 최대 응력과 비교하여 절단면 8 mm, 10 mm, 12 mm, 15 mm 그리고 18 mm에서 최대 응력의 변화에 대한 p-value는 0.389, 0.774, 0.145, 0.005 그리고 0.000 이었고, 연속된 절단면간의 최대 응력 변화는 6 mm와 8 mm, 8 mm와 10 mm, 10 mm와 12 mm, 12 mm와 15 mm 그리고 15 mm와 18 mm에서 p-value는 각각 0.389, 0.502, 0.205, 0.005 그리고 0.021이었다.
결론: 슬관절의 경골 외과측 관절면에서 거리에 따른 절단면의 최대 응력의 변화는 전반적인 감소를 보이나 12 mm이내에서는 최대 응력의 변화가 통계적 의미가 없었고 이를 슬관절 인공관절 치환술시 고려해야 할 것으로 사료된다.Ⅰ. 서론 = 1
Ⅱ. 재료 및 방법 = 10
A. CT의 촬영 및 조건 = 13
B. 유한요소 모델의 생성 및 유한요소 해석 = 18
C. 통계 분석 = 25
Ⅲ. 결과 = 26
Ⅳ. 고찰 = 33
Ⅴ. 결론 = 41
참고문헌 = 42
-ABSTRACT- = 48MasterPurpose: This study carried out to evaluate the mechanical strength of proximal tibia according to resection distance from joint surface and to use this data for total knee arthroplasty.
Materials and Methods: 20 cases of knee computed tomography images were obtained from knee osteoarthritis patients undergoing total knee arthroplasty. Based on computed tomography images, the finite element models were created. The 8-node hexahedron element was made from BIONIX™ (CANTIBio. Co, Suwon, Korea) which is automatic mesh generation software program. The finite element model of proximal tibia was resected to 6 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm from the lateral joint surface. 10% strain rate was applied to model using HyperMeshTM(Altair Engineering. Inc, seattle, USA)software. Ultimated stress was calculated from finite element anaysis using ANSYS 9.0 (ANSYS. Inc, orlando, USA). Paired sample t-test was used for statics.
Results: As compare to 6mm resection level, p value with 8 mm, 10 mm, 12 mm, 15 mm, 18 mm was 0.389, 0.774, 0.145, 0.005, 0.000. As compare to consecutive resection level, p-value was 0.389, 0.502, 0.205, 0.005, 0.021 between 6 mm and 8 mm, 8 mm and 10 mm, 10 mm and 12 mm, 12 mm and 15 mm, 15 mm and 18 mm.
Conclusion: Ultimate strength was decreased according to increasing resection distance from joint surface but Within 12mm resection distance from lateral condyle articular surface of tibia, ultimate strength was not decreased statically significant(p>0.05) and consider it doing total knee arthroplasty
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