Stress Gradient Effects on Notched Composite Failure Using a Local-Global Approach

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77170/1/AIAA-2004-1844-151.pd

A micromechanics based finite element model for the prediction of compressive failure in notched laminated composites

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76816/1/AIAA-2001-1640-412.pd

The elevated temperature compressive response of notched composite laminates

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76750/1/AIAA-1999-1249-577.pd

Integrated analysis procedure of aerospace composite structure

Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2008.Includes bibliographical references (p. 50).The emergence of composite material application in major commercial aircraft design, represented by the Boeing 787 and Airbus A350-XWB, signals a new era in the aerospace industry. The high stiffness to weight ratio of continuous fiber composites (CFC) makes CFCs one of the most important materials to be introduced in modern aircraft industry. In addition to inherent strength (per given weight) of CFCs, they also offer the unusual opportunity to design the structure and material concurrently. The directional properties (and the ability to change these properties through the design process) of composite materials can be used in aeroelastically tailored wings, the fuselage and other critical areas. Due to the longer lifecycle (25-30 years) of a commercial airliner and the tools and processes developed for the airplane of previous product development cycles, new technology often ends up being deployed less effectively because of the mismatch in the technical potential (what can be done) vs. design tools and processes (what was done before). Tools and processes need to be current to take advantage of latest technology, and this thesis will describe one possible approach in primary composite structural design area using integrated structural analysisby Junghyun Ahn.S.M

Computational Thinking in Children: The Impact of Embodiment on Debugging Practices in Programming

Three studies were conducted to better inform how instructional design of educational programming for children impacts learning. In these studies, we focused on how unplugged debugging activities, which require correction of coding errors, affect skills related to computational thinking and personal attributes of children. Study 1 observed debugging performance across varying degrees of embodiment (full and low) with a control group. To identify and rectify coding errors, children in the full embodiment group walked on a floor maze whereas low embodiment group manipulated a paper character using their fingers. Study 2 examined the effects of different degrees of embodiment when combined with either coding or narrative based language on computational thinking and self-efficacy. Children fixed coding errors on a worksheet using coding language or narratives, then performed their revised code using full or low embodiment. Study 3 explored whether congruent or incongruent hand gestures incorporated with either direct or surrogate embodiment enhanced children’s graphic and text programming, self-efficacy, and persistence. In the congruent gesture group, participants placed coding blocks in the same direction that the programming character moves whereas incongruent gesture placed coding blocks in a linear fashion. Direct embodiment is where the participant uses their finger to move a character whereas surrogate embodiment is where the researcher is controlled by the participant through verbal commands. The results on computational thinking skills were: 1) Children performed better in debugging and problem solving using low embodiment; 2) Programming efficiency increased with the use of coding language; 3) Higher performance on graphic programming was found with incongruent gesture while transfer from graphic to text programming improved with surrogate embodiment. In personal attributes: 1) Significant interaction effect was found between hand gesture and embodiment on self-efficacy; 2) Higher persistence was exhibited from direct embodiment. These findings between embodiment and development of computational thinking skills and personal attributes may be utilized in the unplugged learning environment. This is particularly relevant in supporting students to acquire basic computational thinking skills where relevant technology resources are not available

Motion Level-of-Detail: A Simplification Method on Crowd Scene

Recent technological improvement in character animation has increased the number of characters that can appear in a virtual scene. Besides, skeletal and mesh structures are expected to be more complex in the future. Therefore, simulating massive characters' joints in a real-time crowd environment without any preprocessing is unaffordable. We propose a preprocessing method called 'motion level-of-detail' to overcome this limitation. Our 'motion level-of-detail' framework not only minimizes the simulation cost of the joints, but also maintains the similarity between the original and the simplified motion. 'Joint posture clustering (JPC)', which is the skeletal simplification method of our framework, reduces skeletal node by the clusters of similar postures. A cluster is a set of continuous frames, where each frame has similar posture. Because our approach depends on motion trajectory, simplified result preserves the quality of the motion. We also applied a geometric simplification on deformable character mesh, to increase performance. Our approach was particularly useful for the complex skeletal motions that have a monotonous trajectory

From sentence to emotion: a real-time three-dimensional graphics metaphor of emotions extracted from text

This paper presents a novel concept: a graphical representation of human emotion extracted from text sentences. The major contributions of this paper are the following. First, we present a pipeline that extracts, processes, and renders emotion of 3D virtual human (VH). The extraction of emotion is based on data mining statistic of large cyberspace databases. Second, we propose methods to optimize this computational pipeline so that real-time virtual reality rendering can be achieved on common PCs. Third, we use the Poisson distribution to transfer database extracted lexical and language parameters into coherent intensities of valence and arousal—parameters of Russell's circumplex model of emotion. The last contribution is a practical color interpretation of emotion that influences the emotional aspect of rendered VHs. To test our method's efficiency, computational statistics related to classical or untypical cases of emotion are provided. In order to evaluate our approach, we applied our method to diverse areas such as cyberspace forums, comics, and theater dialog

Evaluating the Sensitivity to Virtual Characters Facial Asymmetry in Emotion Synthesis

The use of expressive Virtual Characters is an effective complementary means of communication for social networks offering multi-user 3D-chatting environment. In such context the facial expression channel offers a rich medium to translate the on-going emotions conveyed by the text-based exchanges. However, until recently, only purely symmetric facial expressions have been considered for that purpose. In this article we examine human sensitivity to facial asymmetry in the expression of both basic and complex emotions. The rationale for introducing asymmetry in the display of facial expressions stems from two well established observations in cognitive neuroscience: first that the expression of basic emotions generally displays a small asymmetry, second that more complex emotions such as ambivalent feeling may reflect in the partial display of different, potentially opposite, emotions on each side of the face. A frequent occurrence of this second case results from the conflict between the truly felt emotion and the one that should be displayed due to social conventions. Our main hypothesis is that a much larger expressive and emotional space can only be automatically synthesized by means of facial asymmetry when modelling emotions with a general Valence-Arousal-Dominance dimensional approach. Besides, we want also to explore the general human sensitivity to the introduction of a small degree of asymmetry into the expression of basic emotions. We conducted an experiment by presenting 64 pairs of static facial expressions, one symmetric and one asymmetric, illustrating eight emotions (three basic and five complex ones) alternatively for a male and a female character. Each emotion was presented four times by swapping the symmetric and asymmetric positions and by mirroring the asymmetrical expression. Participants were asked to grade, on a continuous scale, the correctness of each facial expression with respect to a short definition. Results confirm the potential of introducing facial asymmetry for a subset of the complex emotions. Guidelines are proposed for designers of embodied conversational agent and emotionally-reflective avatars

From Sentence to Emotion: a real-time 3D graphics metaphor of emotions extracted from text

This paper presents a novel concept: a graphical representation of human emotion extracted from text sentences. The major contributions of this paper are the following. First, we present a pipeline that extracts, processes, and renders emotion of 3D virtual human (VH). The extraction of emotion is based on data mining statistic of large cyberspace databases. Second, we propose methods to optimize this computational pipeline so that real-time virtual reality rendering can be achieved on common PCs. Third, we use the Poisson distribution to transfer database extracted lexical and language parameters into coherent intensities of valence and arousal—parameters of Russell’s circumplex model of emotion. The last contribution is a practical color interpretation of emotion that influences the emotional aspect of rendered VHs. To test our method’s efficiency, computational statistics related to classical or untypical cases of emotion are provided. In order to evaluate our approach, we applied our method to diverse areas such as cyberspace forums, comics, and theater dialogs