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Description
Ever reducing time to market, along with short product lifetimes, has created a need to shorten the microprocessor design time. Verification of the design and its analysis are two major components of this design cycle. Design validation techniques can be broadly classified into two major categories: simulation based approaches and formal techniques. Simulation based microprocessor validation involves running millions of cycles using random or pseudo random tests and allows verification of the register transfer level (RTL) model against an architectural model, i.e., that the processor executes instructions as required. The validation effort involves model checking to a high level description or simulation of the design against the RTL implementation. Formal techniques exhaustively analyze parts of the design but, do not verify RTL against the architecture specification. The focus of this work is to implement a fully automated validation environment for a MIPS based radiation hardened microprocessor using simulation based approaches. The basic framework uses the classical validation approach in which the design to be validated is described in a Hardware Definition Language (HDL) such as VHDL or Verilog. To implement a simulation based approach a number of random or pseudo random tests are generated. The output of the HDL based design is compared against the one obtained from a "perfect" model implementing similar functionality, a mismatch in the results would thus indicate a bug in the HDL based design. Effort is made to design the environment in such a manner that it can support validation during different stages of the design cycle. The validation environment includes appropriate changes so as to support architecture changes which are introduced because of radiation hardening. The manner in which the validation environment is build is highly dependent on the specifications of the perfect model used for comparisons. This work implements the validation environment for two MIPS simulators as the reference model. Two bugs have been discovered in the RTL model, using simulation based approaches through the validation environment.
ContributorsSharma, Abhishek (Author) / Clark, Lawrence (Thesis advisor) / Holbert, Keith E. (Committee member) / Shrivastava, Aviral (Committee member) / Arizona State University (Publisher)
Created2011
Description
Over recent decades, euthanasia has been a topic of increasing debate. With legalization of euthanasia in the states of Oregon and Washington and attempted reform in several other U.S. states and nations worldwide, it has become increasingly important to understand the roles and values of helping professionals who might be working with clients considering this option. The current study targeted 85 undergraduate students, 54 doctoral students in counseling psychology, and 53 doctoral-level professionals in psychology to assess both their personal values regarding euthanasia and their willingness to allow a client the autonomy to make a decision about euthanasia. Several factors were analyzed in regards to their relation to client autonomy and attitudes toward euthanasia, including age of client and sex of client. These variables were manipulated in vignettes to create four scenarios: a 24 year old male, 24 year old female, 80 year old male, 80 year old female. Other factors included level of education of the participant, spirituality and strength of religiosity of the participant, and personal experiences with deaths of friends or family members. Results indicated that more education was associated with greater support for euthanasia and that stronger religiosity and spirituality were related to less support for euthanasia. This study also found that participants did not exhibit differential levels of support based solely on the age or the sex of the client depicted in the vignette. Results further indicated that for doctoral students and professionals the loss of a loved one, regardless of cause of death, did not have a significant effect on their attitudes toward euthanasia. It is important for training programs to be aware of these findings in order to monitor trainees in terms of personal biases in the therapy relationship. With objectivity a high priority while working with clients, it is necessary to be aware of outside factors potentially influencing one's work with clients surrounding this value-laden issue.
ContributorsBevacqua, Frank (Author) / Robinson-Kurpius, Sharon (Thesis advisor) / Kinnier, Richard (Committee member) / Homer, Judy (Committee member) / Arizona State University (Publisher)
Created2011
Description
ABSTRACT To meet stringent market demands, manufacturers must produce Radio Frequency (RF) transceivers that provide wireless communication between electronic components used in consumer products at extremely low cost. Semiconductor manufacturers are in a steady race to increase integration levels through advanced system-on-chip (SoC) technology. The testing costs of these devices tend to increase with higher integration levels. As the integration levels increase and the devices get faster, the need for high-calibre low cost test equipment become highly dominant. However testing the overall system becomes harder and more expensive. Traditionally, the transceiver system is tested in two steps utilizing high-calibre RF instrumentation and mixed-signal testers, with separate measurement setups for transmitter and receiver paths. Impairments in the RF front-end, such as the I/Q gain and phase imbalance and nonlinearity, severely affect the performance of the device. The transceiver needs to be characterized in terms of these impairments in order to guarantee good performance and specification requirements. The motivation factor for this thesis is to come up with a low cost and computationally simple extraction technique of these impairments. In the proposed extraction technique, the mapping between transmitter input signals and receiver output signals are used to extract the impairment and nonlinearity parameters. This is done with the help of detailed mathematical modeling of the transceiver. While the overall behavior is nonlinear, both linear and nonlinear models to be used under different test setups are developed. A two step extraction technique has been proposed in this work. The extraction of system parameters is performed by using the mathematical model developed along with a genetic algorithm implemented in MATLAB. The technique yields good extraction results with reasonable error. It uses simple mathematical operation which makes the extraction fast and computationally simple when compared to other existing techniques such as traditional two step dedicated approach, Nonlinear Solver (NLS) approach, etc. It employs frequency domain analysis of low frequency input and output signals, over cumbersome time domain computations. Thus a test method, including detailed behavioral modeling of the transceiver, appropriate test signal design along with a simple algorithm for extraction is presented.
ContributorsSreenivassan, Aiswariya (Author) / Ozev, Sule (Thesis advisor) / Kiaei, Sayfe (Committee member) / Bakkaloglu, Bertan (Committee member) / Arizona State University (Publisher)
Created2011
Description
The current study was a benefit cost analysis that examined mental and behavioral health and prescription drug service use data of 347 participants (212 youth and 135 caregivers) from a bereavement intervention, the Family Bereavement Program (FBP).The preliminary goals of the current study were to compare the FBP intervention and the Literature Control (LC) groups at the six year follow-up on: (a) number of participants using mental/behavioral health services and prescription drugs, (b) the frequency of use of mental/behavioral health services and prescription drugs, and (c) the costs of mental/behavioral health services and prescription drugs. The final, and primary goal, was to (d) calculate the benefits of the FBP by analyzing the monetary difference between the LC and FBP groups in terms of cost of services used and then by applying those benefits to the cost of the intervention. Data representing participating youths' and caregivers' mental health service use and prescription drug use at the sixth year post-intervention were collected, as were the costs of those services. Results indicated that fewer FBP participants used services and prescription drugs than the Literature Control (LC) participants, but FBP participants, particularly the youth, used some low intensity services more frequently whereas the LC youth used more intensive and costly services more frequently. Consequently, service costs were greater for participants in the LC group than for participants in the FBP group. The benefit cost ratio revealed that the FBP, as delivered, saved society between $.15 and $.27 in mental and behavioral health costs for every dollar spent on the intervention. Implications of these findings and directions for future research are discussed.
ContributorsPorter, Michèle M (Author) / Hanish, Laura D. (Thesis advisor) / Sandler, Irwin N. (Committee member) / Wolchik, Sharlene A (Committee member) / Johnson, William G. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Two-dimensional vision-based measurement is an ideal choice for measuring small or fragile parts that could be damaged using conventional contact measurement methods. Two-dimensional vision-based measurement systems can be quite expensive putting the technology out of reach of inventors and others. The vision-based measurement tool design developed in this thesis is a low cost alternative that can be made for less than $500US from off-the-shelf parts and free software. The design is based on the USB microscope. The USB microscope was once considered a toy, similar to the telescopes and microscopes of the 17th century, but has recently started finding applications in industry, laboratories, and schools. In order to convert the USB microscope into a measurement tool, research in the following areas was necessary: currently available vision-based measurement systems, machine vision technologies, microscope design, photographic methods, digital imaging, illumination, edge detection, and computer aided drafting applications. The result of the research was a two-dimensional vision-based measurement system that is extremely versatile, easy to use, and, best of all, inexpensive.
ContributorsGraham, Linda L. (Author) / Biekert, Russell (Thesis advisor) / Macia, Narciso (Committee member) / Meitz, Robert (Committee member) / Arizona State University (Publisher)
Created2011
Description
A primary motivation of research in photovoltaic technology is to obtain higher efficiency photovoltaic devices at reduced cost of production so that solar electricity can be cost competitive. The majority of photovoltaic technologies are based on p-n junction, with efficiency potential being much lower than the thermodynamic limits of individual technologies and thereby providing substantial scope for further improvements in efficiency. The thesis explores photovoltaic devices using new physical processes that rely on thin layers and are capable of attaining the thermodynamic limit of photovoltaic technology. Silicon heterostructure is one of the candidate technologies in which thin films induce a minority carrier collecting junction in silicon and the devices can achieve efficiency close to the thermodynamic limits of silicon technology. The thesis proposes and experimentally establishes a new theory explaining the operation of silicon heterostructure solar cells. The theory will assist in identifying the optimum properties of thin film materials for silicon heterostructure and help in design and characterization of the devices, along with aiding in developing new devices based on this technology. The efficiency potential of silicon heterostructure is constrained by the thermodynamic limit (31%) of single junction solar cell and is considerably lower than the limit of photovoltaic conversion (~ 80 %). A further improvement in photovoltaic conversion efficiency is possible by implementing a multiple quasi-fermi level system (MQFL). A MQFL allows the absorption of sub band gap photons with current being extracted at a higher band-gap, thereby allowing to overcome the efficiency limit of single junction devices. A MQFL can be realized either by thin epitaxial layers of alternating higher and lower band gap material with nearly lattice matched (quantum well) or highly lattice mismatched (quantum dot) structure. The thesis identifies the material combination for quantum well structure and calculates the absorption coefficient of a MQFl based on quantum well. GaAsSb (barrier)/InAs(dot) was identified as a candidate material for MQFL using quantum dot. The thesis explains the growth mechanism of GaAsSb and the optimization of GaAsSb and GaAs heterointerface.
ContributorsGhosha, Kuṇāla (Author) / Bowden, Stuart (Thesis advisor) / Honsberg, Christiana (Thesis advisor) / Vasileska, Dragica (Committee member) / Goodnick, Stephen (Committee member) / Arizona State University (Publisher)
Created2011
Description
During adolescence, friends are a central part of adolescents' daily lives, they serve as significant sources of emotional support and companionship (Keefe & Berndt, 1996; Way & Robinson, 2003) as well as provide opportunities to negotiate interpersonal conflicts and disagreements (Laursen & Pursell, 2009). This study was designed to examine the nature and correlates of friendships, capturing the multidimensional nature of these relationships. Specifically, three goals were proposed: (a) to use a pattern-analytic approach to identify different profiles of adolescents' friendships along three dimensions: intimacy, negativity, and involvement; (b) to examine linkages between profile membership and adolescents' cultural orientations and values; and (c) to explore the relation between profile membership and adolescent well-being. Participants were 246 Mexican-origin adolescents (M = 12.50 years; SD = 0.58) who participated in home interviews and a series of nightly phone calls. Adolescents reported on their friendship qualities, their cultural orientations and values, as well as their depressive symptoms, risky behaviors, and on their current grades (GPA). Adolescents' time spent with best friends was calculated from the seven nightly phone calls. Results revealed three distinct latent profiles: Positive Engagement, Moderate Engagement, and Low Involvement. Profile membership was not linked to adolescents' cultural orientations and values. Further, associations emerged between profile membership and adolescents' GPA, but not their risky behaviors and depressive symptoms.
ContributorsRodriguez, Sue Annie (Author) / Updegraff, Kimberly (Thesis advisor) / Umana-Taylor, Adriana (Committee member) / Bradley, Robert (Committee member) / Arizona State University (Publisher)
Created2011
Description
Economic development over the last century has driven a tripling of the world's population, a twenty-fold increase in fossil fuel consumption, and a tripling of traditional biomass consumption. The associated broad income and wealth inequities are retaining over 2 billion people in poverty. Adding to this, fossil fuel combustion is impacting the environment across spatial and temporal scales and the cost of energy is outpacing all other variable costs for most industries. With 60% of world energy delivered in 2008 consumed by the commercial and industrial sector, the fragmented and disparate energy-related decision making within organizations are largely responsible for the inefficient and impacting use of energy resources. The global transition towards sustainable development will require the collective efforts of national, regional, and local governments, institutions, the private sector, and a well-informed public. The leadership role in this transition could be provided by private and public sector organizations, by way of sustainability-oriented organizations, cultures, and infrastructure. The diversity in literature exemplifies the developing nature of sustainability science, with most sustainability assessment approaches and frameworks lacking transformational characteristics, tending to focus on analytical methods. In general, some shortfalls in sustainability assessment processes include lack of: * thorough stakeholder participation in systems and stakeholder mapping, * participatory envisioning of future sustainable states, * normative aggregation of results to provide an overall measure of sustainability, and * influence within strategic decision-making processes. Specific to energy sustainability assessments, while some authors aggregate results to provide overall sustainability scores, assessments have focused solely on energy supply scenarios, while including the deficits discussed above. This paper presents a framework for supporting organizational transition processes towards sustainable energy systems, using systems and stakeholder mapping, participatory envisioning, and sustainability assessment to prepare the development of transition strategies towards realizing long-term energy sustainability. The energy system at Arizona State University's Tempe campus (ASU) in 2008 was used as a baseline to evaluate the sustainability of the current system. From interviews and participatory workshops, energy system stakeholders provided information to map the current system and measure its performance. Utilizing operationalized principles of energy sustainability, stakeholders envisioned a future sustainable state of the energy system, and then developed strategies to begin transition of the current system to its potential future sustainable state. Key findings include stakeholders recognizing that the current energy system is unsustainable as measured against principles of energy sustainability and an envisioned future sustainable state of the energy system. Also, insufficient governmental stakeholder engagement upstream within the current system could lead to added risk as regulations affect energy supply. Energy demand behavior and consumption patterns are insufficiently understood by current stakeholders, limiting participation and accountability from consumers. In conclusion, although this research study focused on the Tempe campus, ASU could apply this process to other campuses thereby improving overall ASU energy system sustainability. Expanding stakeholder engagement upstream within the energy system and better understanding energy consumption behavior can also improve long-term energy sustainability. Finally, benchmarking ASU's performance against its peer universities could expand the current climate commitment of participants to broader sustainability goals.
ContributorsBuch, Rajesh (Author) / Wiek, Arnim (Thesis advisor) / Basile, George (Thesis advisor) / Williams, Eric (Committee member) / Arizona State University (Publisher)
Created2011
Description
Never married parents (NMPs) are a burgeoning population within the Family Court system. However, there is no empirical research on these parents' separation process, though the neighboring literature purports that NMPs are more at risk for negative child wellbeing outcomes than their divorcing counterparts. This study investigated child behavior problems in high conflict litigating never married families by assessing four salient issues collectively termed chaotic environment: economic strain, lack of social support for the parents, parental repartnering, and family relocation, which included parent changing residence and child changing schools. They were then compared to divorcing parents. It was hypothesized that NMPs would experience higher levels of chaotic environment, and subsequent increases in child behavior problems than divorcing parents, but that the relationship for NMPs and divorcing parents would be the same with each of the chaotic environment variables. This study found the contrary. NMPs only had significantly higher mean scores on lack of social support for fathers and marital status did not predict child behavior problems. Both economic strain and child changing schools predicted child behavior problems for both mothers and fathers. Two interaction effects with mothers were found, indicating that the more a never married mothers repartnered and/or changed her residence, the more behavior problems her child had, while divorcing mothers experiencing the converse effect.
ContributorsHita, Liza Cohen (Author) / Braver, Sanford (Thesis advisor) / Sandler, Irwin (Thesis advisor) / Bernstein, Bianca (Committee member) / Homer, Judith (Committee member) / Arizona State University (Publisher)
Created2011
Description
A theme in the life experiences of ethnic minority adolescents is the perception of discrimination and its concomitant challenges. Although existing literature has examined the perception of discrimination in adolescents, little research has examined how the cultural and familial setting may heighten or alleviate the impact of perceived discrimination on psychological outcomes in Latino youth. The current study investigated how traditional cultural values and parent-adolescent relationships prospectively interact with perceptions of group based discrimination to influence Latino adolescent mental health, adjustment, and risky behaviors. Data used from the Parents and Youth Study included 194 Mexican American (MA) adolescents. Adolescents reported on their perceptions of group discrimination, endorsement of traditional Mexican cultural values, and parent-child relationships in the 7th grade (Time 1). The study also used indices of externalizing (mother report), internalizing, substance use and risky sexual behavior (adolescent report) in 10th grade (Time 2). The findings demonstrated that traditional Mexican cultural values, particularly familism, moderated the relationship between perceived group discrimination and adolescent sexual behavior. Additionally, a better overall relationship with mother and father buffered the detrimental effects of perceived group discrimination on risky sexual behavior. The current work discusses future directions of how the context of culture and family may shape an adolescent's response to perceived discrimination and the well-being of minorities.
ContributorsDiaz, Priscila (Author) / Saenz, Delia S. (Thesis advisor) / Kwan, Virginia S.Y. (Committee member) / Gonzales, Nancy (Committee member) / Geiser, Christian (Committee member) / Arizona State University (Publisher)
Created2011