Matching Items (190)
Description
This study focuses on implementing probabilistic nature of material properties (Kevlar® 49) to the existing deterministic finite element analysis (FEA) of fabric based engine containment system through Monte Carlo simulations (MCS) and implementation of probabilistic analysis in engineering designs through Reliability Based Design Optimization (RBDO). First, the emphasis is on experimental data analysis focusing on probabilistic distribution models which characterize the randomness associated with the experimental data. The material properties of Kevlar® 49 are modeled using experimental data analysis and implemented along with an existing spiral modeling scheme (SMS) and user defined constitutive model (UMAT) for fabric based engine containment simulations in LS-DYNA. MCS of the model are performed to observe the failure pattern and exit velocities of the models. Then the solutions are compared with NASA experimental tests and deterministic results. MCS with probabilistic material data give a good prospective on results rather than a single deterministic simulation results. The next part of research is to implement the probabilistic material properties in engineering designs. The main aim of structural design is to obtain optimal solutions. In any case, in a deterministic optimization problem even though the structures are cost effective, it becomes highly unreliable if the uncertainty that may be associated with the system (material properties, loading etc.) is not represented or considered in the solution process. Reliable and optimal solution can be obtained by performing reliability optimization along with the deterministic optimization, which is RBDO. In RBDO problem formulation, in addition to structural performance constraints, reliability constraints are also considered. This part of research starts with introduction to reliability analysis such as first order reliability analysis, second order reliability analysis followed by simulation technique that are performed to obtain probability of failure and reliability of structures. Next, decoupled RBDO procedure is proposed with a new reliability analysis formulation with sensitivity analysis, which is performed to remove the highly reliable constraints in the RBDO, thereby reducing the computational time and function evaluations. Followed by implementation of the reliability analysis concepts and RBDO in finite element 2D truss problems and a planar beam problem are presented and discussed.
ContributorsDeivanayagam, Arumugam (Author) / Rajan, Subramaniam D. (Thesis advisor) / Mobasher, Barzin (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2012
Description
The primary topic of this dissertation is the grammaticalization of negation in three Sinitic language varieties: Hakka, Mandarin, and Southern Min. I discuss negative morphemes that are used under different modality or aspect contexts, including ability, volition, necessity, and perfectivity. Not only does this study examine Southern Min affirmative and negative pairs, but it also highlights the grammaticalization of negation and parametric differences in negation among the languages under investigation. This dissertation also covers the reanalysis of negatives into interrogatives. I approach the investigation of Southern Min negation from both synchronic and diachronic perspectives. I analyze corpus data in addition to data collected from fieldwork for the contemporary linguistic data. For my diachronic research of Chinese negation, I use historical texts and etymological dictionaries. Diachronically, many of the negative morphemes originate from full-fledged verbs and undergo an analogous grammaticalization process that consists of multiple stages of reanalysis from V to T (aspect; modality), and then T to C (interrogative; discourse). I explain this reanalysis, which involves head-to-head movement, using generative frameworks that combine a modified cartographic approach and the Minimalist Economy Principles. Synchronic data show that Southern Min affirmative modals are characterized by a certain morphological doubling. These doublings consist of two near synonyms used in sequence, resulting from the loss of features in a verb and a second verb added as a renewal. In the negation paradigm, some negatives project a negative phrase, while the others serve a dual function, occupying a modal/aspect head as well as a negative head. The latter system is gradually shifting to the former. This study uncovers evidence to counter the long-established paradigm, where negation is tied to its independent modality (abilitive, volitional and necessitive) or aspect (perfective and perfect). I observe a mismatch between the use of interrogatives and their modality/aspect and attribute this phenomenon to feature loss during their reanalysis from negatives to interrogatives. Results however show that consistency occurs in the grammaticalization of negation within Southern Min and intra-linguistically among the three Sinitic languages, and that parametric differences are found at the morphological level.
ContributorsYang, Huiling (Author) / Gelderen, Elly van (Thesis advisor) / Adams, Karen (Committee member) / Gillon, Carrie (Committee member) / Sun, Chaofen (Committee member) / Arizona State University (Publisher)
Created2012
Description
Cognitive Radios (CR) are designed to dynamically reconfigure their transmission and/or reception parameters to utilize the bandwidth efficiently. With a rapidly fluctuating radio environment, spectrum management becomes crucial for cognitive radios. In a Cognitive Radio Ad Hoc Network (CRAHN) setting, the sensing and transmission times of the cognitive radio play a more important role because of the decentralized nature of the network. They have a direct impact on the throughput. Due to the tradeoff between throughput and the sensing time, finding optimal values for sensing time and transmission time is difficult. In this thesis, a method is proposed to improve the throughput of a CRAHN by dynamically changing the sensing and transmission times. To simulate the CRAHN setting, ns-2, the network simulator with an extension for CRAHN is used. The CRAHN extension module implements the required Primary User (PU) and Secondary User (SU) and other CR functionalities to simulate a realistic CRAHN scenario. First, this work presents a detailed analysis of various CR parameters, their interactions, their individual contributions to the throughput to understand how they affect the transmissions in the network. Based on the results of this analysis, changes to the system model in the CRAHN extension are proposed. Instantaneous throughput of the network is introduced in the new model, which helps to determine how the parameters should adapt based on the current throughput. Along with instantaneous throughput, checks are done for interference with the PUs and their transmission power, before modifying these CR parameters. Simulation results demonstrate that the throughput of the CRAHN with the adaptive sensing and transmission times is significantly higher as compared to that of non-adaptive parameters.
ContributorsBapat, Namrata Arun (Author) / Syrotiuk, Violet R. (Thesis advisor) / Ahn, Gail-Joon (Committee member) / Xue, Guoliang (Committee member) / Arizona State University (Publisher)
Created2012
Description
Spanish-speaking (SS) dual language learners (DLLs) have shown differential developmental profiles of the native language (L1). The current study examined whether or not the Spanish acquisition profile, specifically accusative clitics, in predominantly SS, Latino children continues to develop in an English-language contact situation. This study examined (1) accuracy rates of clitic production, total substitutions, and total omissions across 5-, 6-, and 7-year-olds; (2) accuracy rates of clitic production, total substitutions, and total omissions across low and high English proficiency groups; and (3) whether or not there was a trend to use the default clitic lo in inappropriate contexts. Seventy-four SS children aged 5;1 to 7;11 participated in a clitic elicitation task. Results indicated non-significant effects of age and proficiency level on the accuracy of clitic production. These results suggest dual language learners are in an environment that does not foster the maintenance of the L1, at least in the accuracy of accusative clitic pronouns.
ContributorsFigueroa, Megan Danielle (Author) / Restrepo, María A (Thesis advisor) / Gelderen, Elly van (Committee member) / Ingram, David (Committee member) / Arizona State University (Publisher)
Created2012
Description
ABSTRACT This thesis investigates the acceptability of a new variety of English among the English teaching community in Germany. A number of linguists claim there is a new variety of English developing in continental Europe, also known as Euro-English. Their research has surfaced multiple features that are unique to European speakers of English. Twenty-one teachers participated in a survey. They answered a questionnaire consisting of two parts. Part one investigates the background of the teachers, their attitudes towards different varieties of English, and their awareness of the research regarding Euro-English. Part two tests the acceptability of ten features that have been claimed to be specific for mainland Europeans. Results of this study reveal that there is little awareness of non-native varieties and many find it hard to accept the features of Euro-English. However, the teachers show a genuine interest in this topic. Where there is a general preference in holding on to the guidelines of standard norms, many comments indicate that teachers think about issues of identity and how their teaching could be affected by a broader scope that exceeds traditional methods.
ContributorsRaack, Christine (Author) / Gelderen, Elly van (Thesis advisor) / Adams, Karen (Committee member) / Ghanem, Carla (Committee member) / Arizona State University (Publisher)
Created2012
Description
Concrete design has recently seen a shift in focus from prescriptive specifications to performance based specifications with increasing demands for sustainable products. Fiber reinforced composites (FRC) provides unique properties to a material that is very weak under tensile loads. The addition of fibers to a concrete mix provides additional ductility and reduces the propagation of cracks in the concrete structure. It is the fibers that bridge the crack and dissipate the incurred strain energy in the form of a fiber-pullout mechanism. The addition of fibers plays an important role in tunnel lining systems and in reducing shrinkage cracking in high performance concretes. The interest in most design situations is the load where cracking first takes place. Typically the post crack response will exhibit either a load bearing increase as deflection continues, or a load bearing decrease as deflection continues. These behaviors are referred to as strain hardening and strain softening respectively. A strain softening or hardening response is used to model the behavior of different types of fiber reinforced concrete and simulate the experimental flexural response. Closed form equations for moment-curvature response of rectangular beams under four and three point loading in conjunction with crack localization rules are utilized. As a result, the stress distribution that considers a shifting neutral axis can be simulated which provides a more accurate representation of the residual strength of the fiber cement composites. The use of typical residual strength parameters by standards organizations ASTM, JCI and RILEM are examined to be incorrect in their linear elastic assumption of FRC behavior. Finite element models were implemented to study the effects and simulate the load defection response of fiber reinforced shotcrete round discrete panels (RDP's) tested in accordance with ASTM C-1550. The back-calculated material properties from the flexural tests were used as a basis for the FEM material models. Further development of FEM beams were also used to provide additional comparisons in residual strengths of early age samples. A correlation between the RDP and flexural beam test was generated based a relationship between normalized toughness with respect to the newly generated crack surfaces. A set of design equations are proposed using a residual strength correction factor generated by the model and produce the design moment based on specified concrete slab geometry.
ContributorsBarsby, Christopher (Author) / Mobasher, Barzin (Thesis advisor) / Rajan, Subramaniam D. (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2011
Description
Semiconductor scaling technology has led to a sharp growth in transistor counts. This has resulted in an exponential increase on both power dissipation and heat flux (or power density) in modern microprocessors. These microprocessors are integrated as the major components in many modern embedded devices, which offer richer features and attain higher performance than ever before. Therefore, power and thermal management have become the significant design considerations for modern embedded devices. Dynamic voltage/frequency scaling (DVFS) and dynamic power management (DPM) are two well-known hardware capabilities offered by modern embedded processors. However, the power or thermal aware performance optimization is not fully explored for the mainstream embedded processors with discrete DVFS and DPM capabilities. Many key problems have not been answered yet. What is the maximum performance that an embedded processor can achieve under power or thermal constraint for a periodic application? Does there exist an efficient algorithm for the power or thermal management problems with guaranteed quality bound? These questions are hard to be answered because the discrete settings of DVFS and DPM enhance the complexity of many power and thermal management problems, which are generally NP-hard. The dissertation presents a comprehensive study on these NP-hard power and thermal management problems for embedded processors with discrete DVFS and DPM capabilities. In the domain of power management, the dissertation addresses the power minimization problem for real-time schedules, the energy-constrained make-span minimization problem on homogeneous and heterogeneous chip multiprocessors (CMP) architectures, and the battery aware energy management problem with nonlinear battery discharging model. In the domain of thermal management, the work addresses several thermal-constrained performance maximization problems for periodic embedded applications. All the addressed problems are proved to be NP-hard or strongly NP-hard in the study. Then the work focuses on the design of the off-line optimal or polynomial time approximation algorithms as solutions in the problem design space. Several addressed NP-hard problems are tackled by dynamic programming with optimal solutions and pseudo-polynomial run time complexity. Because the optimal algorithms are not efficient in worst case, the fully polynomial time approximation algorithms are provided as more efficient solutions. Some efficient heuristic algorithms are also presented as solutions to several addressed problems. The comprehensive study answers the key questions in order to fully explore the power and thermal management potentials on embedded processors with discrete DVFS and DPM capabilities. The provided solutions enable the theoretical analysis of the maximum performance for periodic embedded applications under power or thermal constraints.
ContributorsZhang, Sushu (Author) / Chatha, Karam S (Thesis advisor) / Cao, Yu (Committee member) / Konjevod, Goran (Committee member) / Vrudhula, Sarma (Committee member) / Xue, Guoliang (Committee member) / Arizona State University (Publisher)
Created2012
Description
The nature of imperative syntax has remained an elusive, yet ever-present, subject in syntactic research, spanning several decades of linguistic inquiry and analysis, and it is therefore unsurprising that current views on the subject continue to be somewhat divided. This thesis examines the syntactic evidence from imperatives in Old English and ultimately seeks to develop a picture of the possibilities for imperative clauses in OE alongside an overall framework for imperative syntax within contemporary theoretical models of syntactic structure. The general, perceived pattern for OE imperative clauses (e.g. Millward 1971) is “verb−first,” and statistical data from the corpora confirm this perception, with the majority of imperative clauses exhibiting the verb in clause−initial position. Imperative constructions with post− and preverbal overt subjects are also examined at length, and postverbal subjects are found to be the majority case. These results are further expanded by examinations of data from verb−second and verb−third contexts, which include possibilities for topicalized constituents and adverbs. Ultimately, the relative position of both the verb and the subject and the relationship between these and other elements in the totality of the data provide essential clues for constructing a clearer model of OE imperative syntax. Within a relatively rich cartographic framework (Rizzi 1997), I therefore argue that the imperative verb is standardly fronted to the head of ForceP, with the overt subject remaining in spec−FinP, in parallel with other models for imperative syntax and OE syntax. Exceptions to this pattern for imperatives which suggest lower positions for the imperative verb (e.g. verb−second and verb−third constructions) are also accounted for, all with the central goal of demonstrating a consistent pattern underlying the realization of imperative syntax in Old English.
ContributorsKruger, William Wriley (Author) / Gelderen, Elly van (Thesis advisor) / Adams, Karen (Committee member) / Major, Roy (Committee member) / Arizona State University (Publisher)
Created2012
Description
Extensive cross-linguistic data document a wide gamut of semantic and pragmatic uses of the diminutive that revolve around the fundamental concepts of `small' and `child'. As typical inventory of informal registers, diminutives are utilized as pragmatic markers of politeness in a wide range of contextual meanings. This dissertation is intended to fill some major gaps in the systematic and empirical research on the formation and pragmatic uses of the diminutives in Macedonian and to explore the role of diminutivization in a broader linguistic framework, by examining the consistency of the field of diminutives, the core and peripheral meanings of the diminutive, their typology, as well as their pragmatic potential. The morphology and pragmatics of the diminutive is examined by combining data from electronic and printed sources, video recordings of natural conversations, as well as from material collected from participant and non-participant observations. At the level of morphology, it is argued that three fundamental semantic constraints underlie the formation of diminutives: [-big], [+ emotional], and [+ informal]. Furthermore, it is shown how diminutive combinability is rule governed in Macedonian by proposing sets of formal constraints for all grades of diminutives. At the level of pragmatics, the pragmatic functions of the diminutives proper and the related periphrastic diminutive malku are investigated in a variety of contexts involving child-directed speech (CDS) and adult communication. By analyzing the pragmatic functions of the diminutive in a series of speech acts, and drawing upon cross-cultural interpretations suggested by Wierzbicka (1991), it is argued that, in Macedonian, social bonding, cordiality, intimacy or affection are pragmatically more salient than personal autonomy in the Anglo-Saxon societies, realized through non-imposition, tentativeness, or similar pragmatic strategies for saving face. Additionally, it is contended that there exist cultural differences in the assessment of the concept of imposition between these societies. The analyses of the pragmatic potential of the diminutive proper and the periphrastic diminutive 'malku' give rise to the claim that Macedonian culture is predominantly founded on the pragmatic principle of positive politeness.
ContributorsSpasovski, Lupco (Author) / Adams, Karen L (Thesis advisor) / Gelderen, Elly van (Committee member) / Sipka, Danko (Committee member) / Arizona State University (Publisher)
Created2012
Description
The purpose of this study is to explore the syntax and pragmatics of subject doubling in spoken French. Many prescriptivists have considered it a redundant and ungrammatical form, but over the years, it has gained more interest from syntacticians. It is widely acknowledged that dislocations involve topics, but the position of these structures is very disputed. Some linguists believe in base generation while others state there is movement. The status of subject clitics also comes into play and their role as arguments or agreement markers is crucial to understanding the issues at stake with a topic analysis. It is often argued that the clitics are undergoing a linguistic cycle whereby they lose their function of argument, and need to be reinforced by disjunct pronouns. In this study, I examined which analyses support my data and I attempted to determine what structures tend to be most dislocated by looking at the environment of the discourse in a corpus of spoken French.
ContributorsBlanquart, Eleonore (Author) / Ossipov, Helene (Thesis advisor) / Bahtchevanova, Mariana (Thesis advisor) / Gelderen, Elly van (Committee member) / Arizona State University (Publisher)
Created2012