Improving the Apparel Virtual Size Fitting Prediction under Psychographic Characteristics and 3D Body Measurements Using Artificial Neural Network

3D virtual simulation prototyping software combined with computer-aided manufacturing systems are widely used and are becoming essential in the fashion industry in the earlier stages of the product development process for apparel design. These technologies streamline the garment product fitting procedures, as well as improve the supply chain environmentally, socially, and economically by eliminating large volumes of redundant samples. Issues of non-standardized selection on garment sizing, ease allowance, and size of 3D avatar for creating 3D garments have been addressed by many researchers. Understanding the relationship between body dimensions, ease allowance, and apparel sizes before adopting virtual garment simulation is fundamental for satisfying high customer demands in the apparel industry. However, designers find difficulties providing the appropriate garment fit for customers without fully understanding the motivation and emotions of customers’ fitting preferences in a virtual world. The main purpose of this study is to investigate apparel sizes for virtual fitting, particularly looking at garment ease with consideration of body dimensions and the psychographic characteristics of subjects. In order to develop a virtual garment fitting prediction model, an artificial neural network (ANN) was applied. We recruited 50 subjects between the ages of 18 and 35 years old to conduct 3D body scans and a questionnaire survey for physical and psychological segmentation, as well as fitting preferences evaluation through co-design operations on virtual garment simulation using a commercial software called Optitex. The results from the study demonstrate that ANN is effective in modeling the non-linear relationship between pattern measurements, psychological characteristics, and body measurements. This new approach and the proposed method of virtual garment fitting model prediction on garment sizes using an Artificial Neural Network (ANN) is significant in prediction accuracy. The project also achieves the concept of mass customization and customer orientation and generates new size-fitting data that can bring a new level of end-user satisfaction

K-nearest neighbor search for fuzzy objects

The K-Nearest Neighbor search (kNN) problem has been investigated extensively in the past due to its broad range of applications. In this paper we study this problem in the context of fuzzy objects that have indeterministic boundaries. Fuzzy objects play an important role in many areas, such as biomedical image databases and GIS. Existing research on fuzzy objects mainly focuses on modelling basic fuzzy object types and operations, leaving the processing of more advanced queries such as kNN query untouched. In this paper, we propose two new kinds of kNN queries for fuzzy objects, Ad-hoc kNN query (AKNN) and Range kNN query (RKNN), to find the k nearest objects qualifying at a probability threshold or within a probability range. For efficient AKNN query processing, we optimize the basic best-first search algorithm by deriving more accurate approximations for the distance function between fuzzy objects and the query object. To improve the performance of RKNN search, effective pruning rules are developed to significantly reduce the search space and further speed up the candidate refinement process. The efficiency of our proposed algorithms as well as the optimization techniques are verified with an extensive set of experiments using both synthetic and real datasets

Predicting student satisfaction of emergency remote learning in higher education during COVID-19 using machine learning techniques

Despite the wide adoption of emergency remote learning (ERL) in higher education during the COVID-19 pandemic, there is insufficient understanding of influencing factors predicting student satisfaction for this novel learning environment in crisis. The present study investigated important predictors in determining the satisfaction of undergraduate students (N = 425) from multiple departments in using ERL at a self-funded university in Hong Kong while Moodle and Microsoft Team are the key learning tools. By comparing the predictive accuracy between multiple regression and machine learning models before and after the use of random forest recursive feature elimination, all multiple regression, and machine learning models showed improved accuracy while the most accurate model was the elastic net regression with 65.2% explained variance. The results show only neutral (4.11 on a 7-point Likert scale) regarding the overall satisfaction score on ERL. Even majority of students are competent in technology and have no obvious issue in accessing learning devices or Wi-Fi, face-to-face learning is more preferable compared to ERL and this is found to be the most important predictor. Besides, the level of efforts made by instructors, the agreement on the appropriateness of the adjusted assessment methods, and the perception of online learning being well delivered are shown to be highly important in determining the satisfaction scores. The results suggest that the need of reviewing the quality and quantity of modified assessment accommodated for ERL and structured class delivery with the suitable amount of interactive learning according to the learning culture and program nature

Digraph Algebras over Discrete Pre-ordered Groups

This thesis consists of studies in the separate fields of operator algebras and non-associative algebras. Two natural operator algebra structures, A ⊗_max B and A ⊗_min B, exist on the tensor product of two given unital operator algebras A and B. Because of the different properties enjoyed by the two tensor products in connection to dilation theory, it is of interest to know when they coincide (completely isometrically). Motivated by earlier work due to Paulsen and Power, we provide conditions relating an operator algebra B and another family {C_i}_i of operator algebras under which, for any operator algebra A, the equality A ⊗_max B = A ⊗_min B either implies, or is implied by, the equalities A ⊗_max C_i = A ⊗_min C_i for every i. These results can be applied to the setting of a discrete group G pre-ordered by a subsemigroup G⁺, where B ⊆ C*_r(G) is the subalgebra of the reduced group C*-algebra of G generated by G⁺, and C_i = A(Q_i) are digraph algebras defined by considering certain pre-ordered subsets Q_i of G. The 16-dimensional algebra A₄ of real sedenions is obtained by applying the Cayley-Dickson doubling process to the real division algebra of octonions. The classification of subalgebras of A₄ up to conjugacy (i.e. by the action of the automorphism group of A₄) was completed in a previous investigation, except for the collection of those subalgebras which are isomorphic to the quaternions. We present a classification of quaternion subalgebras up to conjugacy

Rotordynamics Analyses of a Modified Hydraulic Power Recovery Turbine

Case StudiesProblem Statement, Machine Information, Torsional Model & Assumption, Torsional Response & Results, Tuning Methods, Field Validation, Conclusio

Design and Analysis of Hydraulic Hybrid Passenger Vehicles

University of Minnesota Ph.D. dissertation. September 2015. Major: Mechanical Engineering. Advisors: Perry Li, Thomas Chase. 1 computer file (PDF); x, 305 pages.The research described in this dissertation focuses on the development of computationally efficient design methodology to optimize the hydraulic hybrid power-split transmission for fuel efficiency, acceleration performance and robustness against powertrain uncertainties. This research also involve experimental implementation of a three-level hierarchical control approach on two test beds, requiring powertrain control design and fine-tuning. Hybrid powertrains have the potential to benefit the fuel efficiency of highway and off-highway vehicles. Hydraulic hybrid has high power density. Hydraulic power-split architecture is chosen in this study for its flexibility in operation and combined advantage of series and parallel architecture. An approach for optimizing the configuration and sizing of a hydraulic hybrid power-split transmission is proposed. Instead of considering each mechanical configuration consisting of combinations of gear ratios, a generalized kinematic relation is used to avoid redundant computation. The Lagrange multiplier method for computing the optimal energy management control is shown to be 450 times more computationally efficient for use in transmission design iterations. To exploit the benefit of high power density of hydraulics, a classical multi-objective solver is utilized to incorporate the acceleration performance criteria into the transmission design optimization. By considering worst-case uncertainty, the transmission design is optimized to be robust against powertrain uncertainties and insensitive to operating condition variations, and yet fuel efficient. The Generation I and II vehicles are experimental platforms built to implement controls and to validate the fuel efficiency gain for power-split transmission. The powertrain for the platforms are modeled to predict the potential fuel efficiency improvement by different energy management strategies. Results show maximum of 74\% fuel efficiency gain by optimizing engine management from CVT to full optimal hybrid operation. The three-level control strategy is implemented on the Generation I vehicle. This control strategy segregates the tasks of the drive-train into three layers that respectively 1) manages the accumulator energy storage (high level); 2) performs vehicle level optimization (mid-level); and 3) attains the desired vehicle operating condition (low level). Results validated the modularity and effectiveness of this control structure

Materialien und Architekturen für vollständig lösungsprozessierte organische Solarmodule: materialspezifische Anforderungen für eine verlustminimierte Modulverschaltung

Organic photovoltaics is a promising technology thanks to many advantageous properties, such as printability, semitransparency and flexibility. These properties have attracted a lot of attention both in academia and in industry. The recent breakthrough of power conversion efficiency above 17% is a good case to this point. However, such rapid advances in performance have also left behind many undesirable gaps in other aspects that are critical to the realization of large scale organic photovoltaic modules. One such issue lies on the monolithic interconnections between individual cells in a solar module. Unlike other conventional photovoltaic technologies, which have relatively robust vacuum deposited electrodes, for organic photovoltaics the formation of interconnections of printed electrodes has presented a distinct set of challenges. The goal of this work is to analyse and minimize the electrical losses that are attributed to this interconnection. However, given the wide variety of electrodes that are available and their vastly different properties, this work will narrow its focus on interconnection that are formed with silver. Silver based electrodes are chosen in this work as it is one of the most widely studied electrodes in organic photovoltaics. The first part of this work (Section 4.1) focuses on mimicking and replacing evaporated silver electrodes that are widely used in research and development in organic photovoltaics with printed ones and, thereafter, the realization of organic solar modules with such electrodes. This includes the development of the printable inks and the processes required to fabricate such electrodes. Different organic solar cells are fabricated with such electrodes to showcase their good applicability and compatibility with a large range of materials and structures. More importantly, solar cells with printed silver electrodes have reached a similar performance as evaporated ones. However, despite their apparent similarity, the solar modules that are fabricated with printed silver electrodes perform considerably worse than their evaporated counterparts. Thermal imaging and electrical analysis have revealed that a mere change in processing method can result in a significant difference in the interconnection resistance between the cells. Finally, a remedy to this issue is proposed and the resultant performance difference between both electrode types is less than 4% in a 4 cm2 organic solar module. Overall, this section has demonstrated experimentally that efficient interconnection between cells is an important performance parameter in upscaling organic photovoltaics. The second section (Section 4.2) focuses on developing and analysing the interconnection between transparent electrodes that have comparatively larger sheet resistances than the opaque electrodes discussed in the last section. An analysis of the current-voltage characteristics indicates that the interconnection resistance between silver nanowire (AgNW) top electrode and Indium tin oxide (ITO) bottom electrode is orders of magnitude higher than the interconnection resistance between printed silver and ITO observed in the previous section. Therefore, an alternative approach is presented that can minimize this value. Instead of making a direct connection between the two electrodes, a silver nanoparticle (AgNP) bridge is used instead to connect the two electrodes together. Experimental measurements have indicated that the electrical resistance of printed bridge interconnection is two orders of magnitude lower than the standard gap interconnection. Furthermore, this section has established both theoretically and experimentally, the novel cross bridge Kelvin resistor structure (CBKR) as an accurate tool to measure this intricate electrical parameter. The last section (Section 4.3) focuses on realizing fully printed organic solar module by printed AgNW electrodes only. The various challenges of using AgNW as electrode for organic photovoltaic are first presented and then discussed. The crux of issue, apart from the relatively well-known surface roughness, lies on the low damage threshold of the AgNW network and the relatively low power density of individual AgNWs. This work then showcased in step-by-step fashion how these issues can be addressed or alleviated by following the methodologies that have already been established in the last two sections. By quantitively measuring the interconnection resistance and its power rating, the interconnection between the top and bottom AgNW electrode is optimized and can reliably connect individual cells with minimal electrical and active area losses. Overall, this work has successfully realized fully printed 4 cm2 organic solar modules with close to 5% efficiency. As stated in the beginning, it is almost impossible to provide a solution for every top/bottom electrode combination that is available. Instead, a short guide is provided in section 4.4 with qualitative estimations on the efficiency loss due to interconnection to facilitate and assist readers in their solar module design.Die organische Photovoltaik ist dank zahlreicher vorteilhafter Eigenschaften wie Druckbarkeit, Semitransparenz und Flexibilität eine vielversprechende Technologie. Diese Eigenschaften haben sowohl in der Wissenschaft als auch in der Industrie viel Aufmerksamkeit hervorgerufen. Der jüngste Durchbruch bei der Energieumwandlungseffizienz von über 17 % ist ein gutes Beispiel hierfür. Diese rasanten Fortschritte bei der Effizienz haben jedoch auch viele unerwünschte Lücken in anderen Bereichen hinterlassen, die für die Realisierung von organischen Photovoltaikmodulen im großen Maßstab entscheidend sind. Ein solches Problem liegt in den monolithischen Verbindungen zwischen den einzelnen Zellen eines Solarmoduls. Im Gegensatz zu anderen konventionellen Photovoltaik-Technologien, die über relativ robuste, im Vakuum abgeschiedene Elektroden verfügen, ergeben sich in der organischen Photovoltaik mit gedruckten Elektroden eine Reihe von Herausforderungen. Ziel dieser Arbeit ist es, die elektrischen Verluste zu analysieren und zu minimieren, die auf diese Verbindungen in teilweise oder vollständig gedruckten Elektroden in einem organischen Solarmodul zurückzuführen sind. In Anbetracht der großen Vielfalt der verfügbaren Elektroden und ihrer sehr unterschiedlichen Eigenschaften beschränkt sich diese Arbeit jedoch auf die Verschaltung mit Silber. Elektroden auf Silberbasis werden in dieser Arbeit ausgewählt, da es sich um eine der am meisten untersuchten Elektroden in der organischen Photovoltaik handelt. Der erste Teil dieser Arbeit (Abschnitt 4.1) konzentriert sich auf die Nachahmung und den Ersatz von aufgedampften Silberelektroden, die in der Forschung und Entwicklung im Bereich der organischen Photovoltaik weit verbreitet sind, durch gedruckte Elektroden und die anschließende Herstellung von organischen Solarmodulen mit solchen Elektroden. Dazu gehört die Entwicklung der druckbaren Tinten und der für die Herstellung solcher Elektroden erforderlichen Verfahren. Verschiedene organische Solarzellen werden mit einer solchen Elektrode hergestellt, um ihre gute Anwendbarkeit und Kompatibilität mit einer großen Bandbreite von Materialien und Strukturen zu demonstrieren. Noch wichtiger ist, dass die zellen mit gedruckter Silberelektrode eine ähnliche Effizienz wie die zellen mit aufgedampfter Elektrode erreicht haben. In manchen Fällen bringen Solarmodule, die mit gedruckter Silberelektrode hergestellt wurden, jedoch erheblich schlechtere Leistungen erbringen als Module mit aufgedampften Elektroden. Wärmebildaufnahmen und elektrische Analysen haben gezeigt, dass eine bloße Änderung der Herstellungsmethode zu einem erheblichen Unterschied im Verbindungswiderstand zwischen den Zellen führen kann. Schließlich wird eine Lösung für dieses Problem vorgeschlagen, und der daraus resultierende Leistungsunterschied zwischen den beiden Elektrodentypen kann bei einem 4 cm2 großen organischen Solarmodul weniger als 4 % betragen. Insgesamt konnte in diesem Abschnitt experimentell nachgewiesen werden, dass eine effiziente Verschaltung zwischen den Zellen ein wichtiger Leistungsparameter für die Hochskalierung der organischen Photovoltaik ist. Der zweite Abschnitt (Abschnitt 4.2) konzentriert sich auf die Entwicklung und Analyse der Verbindung zwischen transparenten Elektroden. Eine Analyse der Strom-Spannungs-Kennlinien zeigt, dass der Verbindungswiderstand zwischen der oberen Elektrode aus Silbernanodrähten (AgNW) und der unteren Elektrode aus Indiumzinnoxid (ITO) um Größenordnungen höher ist als der Verbindungswiderstand zwischen gedrucktem Silber und ITO, der im vorherigen Abschnitt beobachtet wurde . Daher wird ein alternativer Ansatz vorgestellt, mit dem dieser Wert minimiert werden kann. Anstatt eine direkte Verbindung zwischen den beiden Elektroden herzustellen, wird eine Brücke aus Silbernanopartikeln (AgNP) verwendet, um die beiden Elektroden miteinander zu verbinden. Experimentelle Messungen haben ergeben, dass der elektrische Widerstand der gedruckten Brückenverbindung um zwei Größenordnungen geringer ist als der der herkömmlichen Verbindung. Darüber hinaus wurde in diesem Abschnitt sowohl theoretisch als auch experimentell nachgewiesen, dass die neuartige Kreuzbrücken-Kelvin-Widerstandsstruktur ein genaues Instrument zur Messung dieses komplizierten elektrischen Parameters ist. Der letzte Abschnitt (Abschnitt 4.3) befasst sich mit der Realisierung eines vollständig gedruckten organischen Solarmoduls ausschließlich mit gedruckten AgNW-Elektroden . Die verschiedenen Probleme bei der Verwendung von AgNW als Elektroden für die organische Photovoltaik werden zunächst vorgestellt und dann diskutiert. Abgesehen von der Oberflächenrauigkeit liegt der Kern des Problems in der niedrigen Zerstörungsschwelle des AgNW-Netzwerks und der relativ geringen Nennleistung der einzelnen AgNWs. In dieser Arbeit wurde dann Schritt für Schritt gezeigt, wie diese Probleme mit Hilfe der in den letzten beiden Abschnitten bereits vorgestellten Methoden angegangen oder abgemildert werden können. Durch die quantitative Messung des Verbindungswiderstands und der Leistung wird die Verbindung zwischen der oberen und unteren AgNW-Elektrode optimiert, so dass einzelne Zellen mit minimalen elektrischen nd Flächenverlusten zuverlässig verbunden werden können. Insgesamt ist es mit dieser Arbeit gelungen, vollständig gedruckte 4 cm2 große organische Solarmodule mit einem Wirkungsgrad von nahezu 5 % zu realisieren. Wie eingangs erwähnt, ist es fast unmöglich, eine Lösung für jede verfügbare Elektrodenkombination zu finden. Stattdessen wird in Abschnitt 4.4 ein kurzer Leitfaden mit qualitativen Schätzungen zum Wirkungsgradverlust aufgrund der Verschaltung bereitgestellt, um den Lesern die Auslegung ihrer Solarmodule zu erleichtern

Evaluating the impact of peer coaching through teachers' teaching principles

The English language programme of the Macau University of Science and Technology (MUST) has a pressing need for a continuing professional development (CPD) programme. Peer coaching is identified as the type of CPD that is potentially suitable for the English programme. It also serves as a catalyst for building a learning community. The main purpose of this study is to examine the impact of a peer coaching programme on the teachers’ beliefs and practice. To do so, I investigate the difference in teachers’ teaching principles (please see Section 5 of Chapter 2 for details) in direct relation to their actual classroom practice before and after the peer coaching programme in one school term. By comparing how the teachers make sense of their actual classroom practices before and after the programme, this study can address the impact of the peer coaching programme on the teachers’ theories-in-use and has important implications for understanding and improving teaching. This study also attempts to investigate to what extent peer coaching helps to build a learning community. This study found that peer coaching could help to change the teachers' beliefs and perceptions in various extents, which led to changes in teachers' practice. Trust is found to be an important element in a successful peer coaching relationship. This study also found that peer coaching can help to promote an articulate, reflective, and collaborative work culture, which should facilitate and sustain teachers’ professional development, promote teacher leadership and contribute to educational improvement