Circuit assembly and packaging technologies for power electronics have not kept pace with those for digital electronics. Inside those packaged power devices as well as the state-of-the-art power modules, interconnection of power chips is accomplished with wirebonds. Wirebonds in power devices and modules are prone to resistance, noise, parasitic oscillations, fatigue and eventual failure. Furthermore, there has been an increase demand for higher power density and better efficiency for power converters. Power semiconductor suppliers have been concentrating on improving device structure, density, and process technology to lower the on-resistance of MOSFETs and voltage drop of IGBTs. Recent advances made in power semiconductor technology are pushing packaging technology to the limits for performance of these power systems since the resistance and parasitics contribution by the package and the wirebonds are roughly the same as that on the silicon. In recent years, an integrated systems approach to standardizing power electronics components and packaging techniques in the form of power electronics building blocks has emerged as a new concept in the area of power electronics. As a result, it has been envisioned that the packaging of three-dimensional high-density multichip modules (MCMs) can meet the requirement for future power electronics systems. However, the conventional wirebond interconnected power devices are excluded from three-dimensional MCMs because of their large size, limited thermal management, and incompatible processing techniques. On the other hand, advanced solder joint area-array technologies, such as flip-chip technology, has emerged in microelectronics industry due to increased speed, higher packaging density, and performance, improved reliability and low cost these technologies offer. With all these benefits to offer, solder joint area-array technology has yet to be implemented for power electronics packaging. Therefore, the first objective of this study is to design and develop a solder joint area-array interconnection technique for power chips. Solder joint reliability is a major concern for area array technologies and power chip interconnection, thus the second objective of this study is to evaluate solder joint reliability, investigate the fatigue failure behavior of solder joint and improve solder joint reliability by developing a new solder bumping process for improved solder joint geometry, underfilling solder joint with encapsulant and applying flexible substrate in the assembly. The third objective is the implementation of solder joint interconnection technique in developing chip-scale power packages and a three-dimensional integrated power electronics module structure. Solder joint area array interconnection for power chips has been designed with the considerations of parasitic resistance and inductance reduction, current handling capability, thermal management, reliability improvement and manufacturability. A new solder joint fabrication process, which is able to produce high standoff hourglass-shaped solder joint that consists of an inner cap, middle ball and outer cap, as well as the conventional solder bumping process have been successfully developed for power chips by using stencil printing. This solder bumping technology is compatible with the existing surface-mount assembly operations and potentially low cost. The fabricated solder joints have been characterized for their structure integrity, mechanical strength and electrical performances. Solder joint reliability has been improved by optimizing solder joint geometry, underfilling flipped power chip and utilizing compliant substrate. Solder joint reliability was evaluated using accelerated temperate cycling and adhesion tests. The interfaces of the triple-stacked solder joints were examined using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) for the integrity of the joint. Acoustic microscopy imaging (nondestructive evaluation) was utilized to examine the quality of the bonded interfaces and to detect cracks and other defects before and during accelerated fatigue tests. Adhesion strength of both single bump barrel-shaped and stacked hourglass-shaped solder joints to bonding pads was characterized and analyzed. It was found that stacked hourglass-shaped solder joint have higher fracture stress than barrel-shaped solder joint. This verifies that hourglass-shaped solder joint has lower stress singularity at the interface between the solder bump and the silicon die as well as at the interface between the solder bump and substrate than barrel-shaped solder joint, especially around the corners of the interfaces. Furthermore, the adhesion strength of barrel-shaped solder joint decreases much faster than that of high standoff hourglass-shaped solder joint under temperature cycling, which indicates that the latter has high reliability than the former. Our accelerated temperature cycling test clearly shows that solder joint fatigue failure process consists of three phases: crack initiation, crack propagation and catastrophic failure. Solder joint geometry, underfilling and substrate flexibility were proved to affect solder joint reliability. The effects of solder joint shape and standoff height on reliability have been systematically studied experimentally for the first time. Our experimental results indicated that both hourglass shape and great standoff height could improve solder joint fatigue lifetime, with standoff height being the more effective factor. The fatigue lifetime of high standoff hourglass-shaped solder joint is improved mainly by prolonged crack propagation time, with slight improvement in crack initiation time. Experimental data suggested that shape is the dominant factor affecting crack initiation time while standoff height is the major factor influencing crack propagation time. Underfilling and flexible substrate improved the lifetime of both barrel and hourglass-shaped solder joints. The effect of underfill on solder joint reliability is well known in microelectronics packaging field. However, for the first time, it is reported in this study that flex substrate could improve solder joint reliability. It has been found that flex substrate bucks during temperature cycling and thus reduces thermal strain in solder joints, which in turn improves solder joint fatigue lifetime. Chip scale packaging can enable a few very important concepts and advantages in power electronics packaging. It offers high silicon to package footprint ratio, provides a known good die solution to power chips, improves electrical as well as thermal performance and creates an opportunity for power component standardization. Two kinds of chip-scale power packages have been developed in this research. One is called cavity down flip chip on flex; the other is termed Die Dimensional Ball Grid Array (D2BGA). Both utilize solder joint as chip-level interconnection. Electrical tests show that the VCE(sat) of the high speed IGBT chip-scale packages is improved by 20% to 30% by eliminating the device¡¯s wirebonds and other external interconnections, such as leadframe. Double-sided cooling is realized in these CSPs. Temperature cycling test shows that the CSPs are reliable. Integrated power electronics modules (IPEMs) are envisioned as integrated power modules consisting of power semiconductor devices, power integrated circuits, sensors, and protection circuits for a wide range of power electronics applications, such as inverters for motor drives and converters for power processing equipment. We have developed a three-dimensional approach, termed flip chip on flex (FCOF), for packaging high-performance IPEMs. The new concept is based on the use of solder joint (D2BGA chip scale package), not bonding wires, to interconnect power devices. This packaging approach has the potential to produce modules having superior electrical and thermal performance and improved reliability. We have demonstrated the feasibility of this approach by constructing half-bridge converters (consisting of two IGBTs, two power diodes, and a simple gate driver circuitry) which have been successfully tested at power levels over 30 kW. Switching tests have shown that parasitic inductance of the FCOF module has been reduced by 40% to 50% over conventional wire bond power modules. Better thermal management can be achieved in this three-dimensional power module structure. Compared with the state-of-the-art half-bridge power modules, the volume of the half-bridge FCOF power module is reduced by at least 65%. Reliability test shows that this flip chip on flex power module structure is potentially more reliable than wire bond power module. / Ph. D.

Many students with intellectual disabilities and autism struggle to have meaningful social interactions with their peers. Research shows that using video modeling can increase social skills in students with disabilities, but it has never been studied in comparison to or in combination with “IF….THEN…” behavior contracts. The purpose of this study is to examine the effects of video prompts on elementary-aged students with disabilities to increase appropriate social interactions with their peers through filming the creation of an “IF….THEN…”contract. The participants are four elementary-aged students with intellectual disabilities and autism who have target social skills deficits. The targeted social skills were: greeting peers, initiating conversations, and asking peers to play. The use of “IF….THEN…” contracts, contracts plus structured review, and contracts plus video prompting was evaluated. Each participant had a baseline of zero and after treatment increased the frequency of social skills from one to three instances. Data collected showed both the interventions of “IF….THEN….” contracts plus structured review and contracts plus video prompting were similarly effective at increasing social skills. Treatment had lasting effects in three of the participants when it was completely phased out.

Indiana University-Purdue University Indianapolis (IUPUI) / Observational studies and clinical trials with time-to-event data frequently involve multiple event types, known as competing risks. The cumulative incidence function (CIF) is a particularly useful parameter as it explicitly quantifies clinical prognosis. Common issues in competing risks data analysis on the CIF include interval censoring, missing event types, and left truncation. Interval censoring occurs when the event time is not observed but is only known to lie between two observation times, such as clinic visits. Left truncation, also known as delayed entry, is the phenomenon where certain participants enter the study after the onset of disease under study. These individuals with an event prior to their potential study entry time are not included in the analysis and this can induce selection bias. In order to address unmet needs in appropriate methods and software for competing risks data analysis, this thesis focuses the following development of application and methods. First, we develop a convenient and exible tool, the R package intccr, that performs semiparametric regression analysis on the CIF for interval-censored competing risks data. Second, we adopt the augmented inverse probability weighting method to deal with both interval censoring and missing event types. We show that the resulting estimates are consistent and double robust. We illustrate this method using data from the East-African International Epidemiology Databases to Evaluate AIDS (IeDEA EA) where a significant portion of the event types is missing. Last, we develop an estimation method for semiparametric analysis on the CIF for competing risks data subject to both interval censoring and left truncation. This method is applied to the Indianapolis-Ibadan Dementia Project to identify prognostic factors of dementia in elder adults. Overall, the methods developed here are incorporated in the R package intccr. / 2021-05-06

This thesis is focused on design and implementation of toolchain for compilation and installation of RPM packages from SRPM packages in Fedora Linux distribution. Tools can be set up to modify compiler options and rpm macros. A tool for custom compilation of Linux kernel was also implemented. This tool builds the kernel with default options or according to configuration supplied by user. The toolchain was used to create customized distribution. Resulting distribution contains these tools for compilation and installation of additional software.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第12801号 / 論医博第2073号 / 新制||医||1001(附属図書館) / 80845 / 京都大学大学院薬学研究科創薬科学専攻 / (主査)教授 川上 浩司, 教授 松原 和夫, 教授 今中 雄一 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Projektet avhandlar en specifik testmetod avseende hur en kartongförpackning reagerar på krafter den utsätts för när den belastas av ett artificiellt finger (BioTac), detta i syfte att undersöka om testmetoderna genererar objektiva och repeterbara resultat.   Projektet analyserar också hur en förvald kartongförpackning böjs vid en specifik punktlast, samt vilken resulterande omslutning och nedböjningen som då registreras av BioTacen. Metoderna som används kompletteras med testresultat utförda med hjälp av laborativa verktyg; en dragprovsmaskin tillverkad av Lloyd instruments med tillsatsen en haptisk sensor (BioTac) från Syntouch.  Vidare forskning har lett till ett mer definierat och objektivt sätt att mäta bland annat en förpacknings grepp-styvhet, vilket bidragit till en ökad förståelse för hur en förpackning ska konstrueras för att bäst tjäna dess syfte. / The project deals with a specific test method regarding how a cardboard package reacts to the external forces when an artificial finger (BioTac) is forced upon it, the purpose being to examine if the method generates objective and repeatable results.  The project also analyses how a pre-selected cardboard package bends at a certain load, and which the resulting enclosure is registered by the BioTac. The methods used are supplemented with laboratory tools, such as: A tensile testing machine by Lloyd instruments, in addition with a tactile sensor (BioTac) by Syntouch.  Further research has led to a more defined and objective way of measuring, amongst other things, a packaging’s grip-stiffness, which has contributed to an increased understanding of how a package should be designed to best serve its purpose.

Advances in modern technologies have led to an abundance of high-dimensional time series data in many fields, including finance, economics, health, engineering, and meteorology, among others. This causes the “curse of dimensionality” problem in both univariate and multivariate time series data. The main objective of time series analysis is to make inferences about the conditional distributions. There are some methods in the literature to estimate the conditional mean and conditional variance functions in time series. However, most of those are inefficient, computationally intensive, or suffer from the overparameterization. We propose some dimension reduction techniques to address the curse of dimensionality in high-dimensional time series dataFor high-dimensional matrix-valued time series data, there are a limited number of methods in the literature that can preserve the matrix structure and reduce the number of parameters significantly (Samadi, 2014, Chen et al., 2021). However, those models cannot distinguish between relevant and irrelevant information and yet suffer from the overparameterization. We propose a novel dimension reduction technique for matrix-variate time series data called the "envelope matrix autoregressive model" (EMAR), which offers substantial dimension reduction and links the mean function and the covariance matrix of the model by using the minimal reducing subspace of the covariance matrix. The proposed model can identify and remove irrelevant information and can achieve substantial efficiency gains by significantly reducing the total number of parameters. We derive the asymptotic properties of the proposed maximum likelihood estimators of the EMAR model. Extensive simulation studies and a real data analysis are conducted to corroborate our theoretical results and to illustrate the finite sample performance of the proposed EMAR model.For univariate time series, we propose sufficient dimension reduction (SDR) methods based on some integral transformation approaches that can preserve sufficient information about the response. In particular, we use the Fourier and Convolution transformation methods (FM and CM) to perform sufficient dimension reduction in univariate time series and estimate the time series central subspace (TS-CS), the time series mean subspace (TS-CMS), and the time series variance subspace (TS-CVS). Using FM and CM procedures and with some distributional assumptions, we derive candidate matrices that can fully recover the TS-CS, TS-CMS, and TS-CVS, and propose an explicit estimate of the candidate matrices. The asymptotic properties of the proposed estimators are established under both normality and non-normality assumptions. Moreover, we develop some data-drive methods to estimate the dimension of the time series central subspaces as well as the lag order. Our simulation results and real data analyses reveal that the proposed methods are not only significantly more efficient and accurate but also offer substantial computational efficiency compared to the existing methods in the literature. Moreover, we develop an R package entitled “sdrt” to easily perform our program code in FM and CM procedures to estimate suffices dimension reduction subspaces in univariate time series.

There is a high dependency on accurate finite element models in the packaging industry for concept selection, design and virtual validation of packages. One of themost used materials for these packages is High-Density Polyethylene (HDPE). Thismaterial is highly anisotropic, strain rate dependent and has different behavior intension and compression.The objective of this thesis is to improve the existing constitutive model of HDPEthrough additional material characterization experiments and validate those models.For this purpose, strain rate dependencies of the material on elastic and hardeningresponse are included in the constitutive model. In addition to that, the compressivebehavior of HDPE was incorporated in the model as well. The anisotropy of HDPEwas modeled using the Hill48 yield criterion which was characterized by performingmultiple uniaxial tensile tests in the three directions: Machine Direction (MD), 45◦and Cross Direction (CD).Validation was done on the coupon test and compression test on the package.The result displayed that the results from the physical test are comparable with theresults obtained from the FE-models.From the tensile tests, the deformation of HDPE in MD and 45◦ was successfullycaptured and validated. While for the CD direction, the deformation could be captured but not validated against FE-model. Furthermore, the test results displayedthat the material HDPE exhibits a significant degree of anisotropy. In conclusion,the project contributed knowledge and understanding of how a Tetra Pak® packagebehaved during top load compression / Det finns ett stort behov av exakta finita element-modeller inom förpackningsindustrin för konceptval, design och virtuell validering av paket. Ett av de mest användamaterialen för dessa förpackningar är Högdensitetspolyeten (HDPE). Detta materialär mycket anisotropiskt, töjningshastighetsberoende och har olika beteende i dragoch tryckspänning.Syftet med detta projektet är att förbättra den befintliga konstitutiva modellenav HDPE genom ytterligare materialkaraktärisering för experimenten och valideradessa modeller. För detta ändamål ingår töjningshastighet hos materialet för elasticitet och spänning-töjningskurva i den konstitutiva modellen. Utöver det användsäven HDPE:s tryckbeteende i modellen. Anisotropin av HDPE modellerades medanvändning av Hill48 som kännetecknades av att utföra flera enaxliga dragtester itre riktningar: Machine Direction (MD), 45◦ och Cross Direction (CD).Validering gjordes på dragprovstestet och trycktestet på förpackningen. Resultatet visade att resultaten från det fysiska testet är jämförbara med resultaten frånFE-modellerna.Från dragprovstesterna fångades och validerades deformationen av HDPE i MDoch 45◦framgångsrikt. Medan för CD-riktningen kunde deformationen fångas meninte valideras mot FE-modellen. Testresultaten visade också att materialet HDPEuppvisar en betydande grad av anisotropi. Sammanfattningsvis bidrog projektet medkunskap och förståelse för hur ett Tetra Pak®-paket betedde sig under trycktest

No description available.

The research adds to current management control system and textile and fashion management literature by developing a MCS framework which is specially targeting startups within the textile and fashion industry in order to implement and scale sustainability initiatives. The framework provides potential to impact and facilitate managers to foster sustainable development. Given the lack of research and the resulting lack of knowledge and understanding of sustainable development from a managerial perspective in the textile and fashion context, this research adds knowledge by examining fashion startups which find themselves at the development phase of MCSs.