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Stephen Ekwaro-Osire

Bio: Stephen Ekwaro-Osire is an academic researcher from Texas Tech University. The author has contributed to research in topics: Probabilistic logic & Pressure angle. The author has an hindex of 15, co-authored 135 publications receiving 926 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a dynamic model was developed, using MATLAB, and used for the prediction of the instantaneous dynamic loads of spur gears with symmetric and asymmetric teeth, and a 2-D three-tooth model for finite element analysis.

91 citations

Journal ArticleDOI
01 Jun 2010-Knee
TL;DR: There is a complete lack of correlation between "total" ACL strain and QPF suggesting that the total strain in the ACL is independent of the QPF under the simulated conditions, indicating that elevated QPF increases pre-activation strain but reduces the landing strain and is therefore protective post-landing.
Abstract: article i nfo We hypothesize that application of an unopposed quadriceps force coupled with an impulsive ground reaction force may induce anterior cruciate ligament (ACL) injury. This situation is similar to landing from a jump if only the quadriceps muscle is active; an unlikely but presumably dangerous circumstance. The purpose of this study was to test our hypothesis using in vitro simulation of jump landing. A jump-landing simulator was utilized. Nine cadaveric knees were tested at an initial flexion angle of 20°. Each ACL was instrumented with a differential variable reluctance transducer (DVRT). Quadriceps pre-activation forces (QPFs) ranging from 25 N to 700 N were applied to each knee, followed by an impulsive ground reaction force produced by a carriage-mounted drop weight (7 kg) that impulsively drove the ankle upward. ACL strain was monitored before landing due to application of QPF (pre-activation strain) and at landing due to application of the ground reaction force (landing strain). No ACLs were injured. Pre-activation strains exhibited a positive correlation with QPF (r=0.674, pb0.001) while landing strains showed a negative correlation (r=�0.235, p=0.032). Total ACL strain (pre-activation+landing strain) showed no correlation with QPF (r=0.023, p=0.428). Our findings indicate that elevated QPF increases pre-activation strain but reduces the landing strain and is therefore protective post-landing. Overall, there is a complete lack of correlation between "total" ACL strain and QPF suggesting that the total strain in the ACL is independent of the QPF under the simulated conditions.

62 citations

Journal ArticleDOI
TL;DR: There exists a need to continue research on the development of tools that simulate flows in a life-cycle and optimize them and these tools should be based on the client-server model base on the Internet to facilitate the e-Transition.
Abstract: Life-cycle engineering (LCE) is a decision-making methodology that considers performance, environmental and cost requirements for the duration of a product This methodology is becoming a norm for global companies that want to remain competitive To facilitate and enhance the application of LCE methodology to industrial products, a number of computer tools or utilities that require minimal user input, and hence run automatically in the background of the design process, have been developed These utilities are intended to provide a feedback on an evolving design without impeding or hampering the design process There exists a need to continue research on the development of tools that simulate flows in a life-cycle and optimize them These tools should be based on the client-server model base on the Internet to facilitate the e-Transition

56 citations

Journal ArticleDOI
TL;DR: In this paper, the impact of tip relief modification and pressure angle on the wear of asymmetric spur gears with asymmetric teeth is numerically investigated and a wear model based on Archard's equation is employed to predict wear depth.
Abstract: Recently, spur gears with asymmetric teeth have been considered a way of increasing performance while maintaining the gearbox dimensions. Asymmetric teeth have different pressure angles on drive and coast sides. They provide, among other advantages, a high bending strength and low vibration. In spur gears with asymmetric teeth, wear has been observed to be a major failure mode. In this study, the impact of tip relief modification and pressure angle on the wear of spur gears with asymmetric teeth is numerically investigated. Here, the focus is on sliding wear. A wear model based on Archard's equation is employed to predict wear depth. The pressure angle and the tip relief are parameterized. In the analysis, instantaneous contact loads and Hertz pressures are used in wear depth calculations. It is shown that as the amount of the tip relief increases, the wear depth, particularly at the beginning and end of the mesh, decreases. As the number of wear cycles increases, the effect of the tip relief modification...

49 citations

Journal Article
TL;DR: This paper presents recent developments and current activities of DfE, specifically, the areas of decision-making, design support, material flow analysis and application, and a brief discussion of future trends is presented.
Abstract: Design for Environment (DfE) optimizes the relationship and interaction of the economic system and the environmental system, and strives to produce a sustainable development and enterprise integration. The driving force behind DfE includes customers, international agencies, and governmental agencies, who are all stake holders in the environmental well being. The methodologies and tools of DfE generally fall under three loose categories, namely, decision making, design support, and material flow. In DfE, there are a number of enablers for decision making, examples of which include end-of-life strategies and Life Cycle Assessment (LCA). With the development of DfE, sophisticated design support methodologies and tools are necessary for the early stage of design regarding the environmental impact, working as guidance to the design engineers. The three main design support constituents, discussed in this paper, include LCA, Design for Disassembly, and Expert Systems. Environmental impact resulting from modern industry has spurred interest in the material and energy flows of industry systems. These flows are viewed not only to be fundamental to environmental problems, but also as agents of financial success. The scope of DfE has three elements, namely, strategy, guidelines and procedures, and application. It is noted that the next frontier of DfE is the incorporation of society models that include technology, government, customers, recyclers, and their respective interaction. This paper presents recent developments and current activities of DfE, specifically, the areas of decision-making, design support, material flow analysis and application. Additionally, a brief discussion of future trends is presented and observations are made on how to further realize DfE in industry and in the entire society while protecting the environment.

48 citations


Cited by
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Christopher M. Bishop1
01 Jan 2006
TL;DR: Probability distributions of linear models for regression and classification are given in this article, along with a discussion of combining models and combining models in the context of machine learning and classification.
Abstract: Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

10,141 citations

Book
01 Jan 1995
TL;DR: In this article, Nonaka and Takeuchi argue that Japanese firms are successful precisely because they are innovative, because they create new knowledge and use it to produce successful products and technologies, and they reveal how Japanese companies translate tacit to explicit knowledge.
Abstract: How has Japan become a major economic power, a world leader in the automotive and electronics industries? What is the secret of their success? The consensus has been that, though the Japanese are not particularly innovative, they are exceptionally skilful at imitation, at improving products that already exist. But now two leading Japanese business experts, Ikujiro Nonaka and Hiro Takeuchi, turn this conventional wisdom on its head: Japanese firms are successful, they contend, precisely because they are innovative, because they create new knowledge and use it to produce successful products and technologies. Examining case studies drawn from such firms as Honda, Canon, Matsushita, NEC, 3M, GE, and the U.S. Marines, this book reveals how Japanese companies translate tacit to explicit knowledge and use it to produce new processes, products, and services.

7,448 citations

Journal ArticleDOI

1,549 citations

Journal ArticleDOI
TL;DR: The main focus will be on the different approaches to perform robust optimization in practice including the methods of mathematical programming, deterministic nonlinear optimization, and direct search methods such as stochastic approximation and evolutionary computation.

1,435 citations

Journal ArticleDOI
TL;DR: In this paper, a review brings together research on life cycle assessment (LCA) applied within the building sector, focusing on the LCA methodology and tools employed in the built environment.

1,103 citations