Characterizing the influence of neutron fields in causing single-event effects using portable detectors

The malfunction of semiconductor devices caused by cosmic rays is known as Single Event Effects(SEEs). In the atmosphere, secondary neutrons are the dominant particles causing this effect. The neutron flux density in atmosphere is very low. For a good statistical certainty, millions of device hours are required to measure the event rate of a device in the natural environment. Event rates obtained in such testings are accurate. To reduce the cost and time of getting the event rate, a device is normally taken to artificial accelerated neutron beams to measure its sensitivity to neutrons. Comparing the flux density of the beam and the flux density of a location in the atmosphere, the real time event rate can be predicted by the event rate obtained. This testing method was standardized as the neutron accelerated soft error rate (ASER) testing in JEDEC JESD89A standard. However, several life testings indicated that the neutron flux density predictions given by the accelerated testings can have large errors. Up to a factor of 2 discrepancy was reported in the literature. One of the major error sources is the equivalence of the absolute neutron flux density in the atmosphere and in accelerated beam. This thesis proposes an alternative accelerated method of predicting the real-time neutron error rate by using proxy devices. This method can avoid the error introduced by the uncertainty in the neutron flux density. The Imaging Single Event Effect Monitor (ISEEM) is one of the proxy devices. It is the instrument originally developed by Z. Török and his co-workers in the University of Central Lancashire. A CCD was used as the sensitive element to detect neutrons. A large amount of data sets acquired by Török were used in this work. A re-engineered ISEEM has been developed in this work to improve ISEEM performance in life testings. Theoretical models have been developed to analyze the response of ISEEM in a wide range of neutron facilities and natural environment. The agreement of the measured and calculated cross-sections are within the error quoted by facilities. Because of the alpha contamination and primary proton direct ionization effects, performance of ISEEM in life testings appeared to be weak

Performance evaluation of warehouses with automated storage and retrieval technologies.

In this dissertation, we study the performance evaluation of two automated warehouse material handling (MH) technologies - automated storage/retrieval system (AS/RS) and autonomous vehicle storage/retrieval system (AVS/RS). AS/RS is a traditional automated warehouse MH technology and has been used for more than five decades. AVS/RS is a relatively new automated warehouse MH technology and an alternative to AS/RS. There are two possible configurations of AVS/RS: AVS/RS with tier-captive vehicles and AVS/RS with tier-to-tier vehicles. We model the AS/RS and both configurations of the AVS/RS as queueing networks. We analyze and develop approximate algorithms for these network models and use them to estimate performance of the two automated warehouse MH technologies. Chapter 2 contains two parts. The first part is a brief review of existing papers about AS/RS and AVS/RS. The second part is a methodological review of queueing network theory, which serves as a building block for our study. In Chapter 3, we model AS/RSs and AVS/RSs with tier-captive vehicles as open queueing networks (OQNs). We show how to analyze OQNs and estimate related performance measures. We then apply an existing OQN analyzer to compare the two MH technologies and answer various design questions. In Chapter 4 and Chapter 5, we present some efficient algorithms to solve SOQN. We show how to model AVS/RSs with tier-to-tier vehicles as SOQNs and evaluate performance of these designs in Chapter 6. AVS/RS is a relatively new automated warehouse design technology. Hence, there are few efficient analytical tools to evaluate performance measures of this technology. We developed some efficient algorithms based on SOQN to quickly and effectively evaluate performance of AVS/RS. Additionally, we present a tool that helps a warehouse designer during the concepting stage to determine the type of MH technology to use, analyze numerous alternate warehouse configurations and select one of these for final implementation

The crystal of everyday life: the ethics of witness in Hou Hsiao-hsien's films

This dissertation explores the aesthetic and ethical ways in which history and daily life are filmically represented and witnessed in Taiwanese director, Hou Hsiao-hsien’s movies. From the era of the Japanese Occupation to the White Horror and then to the lifting of martial law, I show how Hou Hsiao-hsien uses visual media to evoke the rhythms of daily life through the emotional memory of the characters and communities he explores. In particular, I focus on the ways in which he seeks to reflect the strong dilemmas of identity and the traumatic emotions about the witness to history. To this end, this dissertation interrogates the work of Hou Hsiao-hsien to ask: “What means are available to a film director to both explore, and incorporate, historical events and observations into a film?”, “How does the camera work in the telling of such historical events?” “What is the role of film in illuminating the grounds of truth - telling at any moment the contemporary ethics of particular histories?” “How does film represent historical trauma and the personal memories that go with that trauma?” To answer these questions, with respect to the work of the film-maker, Hou Hsia-hsien, I present some of the formal practices that he uses, in the way he questions and represents history and daily life, in his films, in order to demonstrate both historical responsibility, in general, and a reliable ‘ethics of witness’ in particular. I argue that in better understanding Hou’s films we need to move beyond an analysis which is dominated by a critical theory which prioritises simply imaginative vision, to a theoretical understanding of film which seeks to question how individual experience in feature films is related to history and collective memory. I argue that Hou’s films go beyond an imagination which uses history and memory as a backdrop, to being powerful interventions, deconstructing the power and authority of the “voice-over” of “official” history. As such, Hou’s films do not simply record past memories, they become part of the overall “ethics of witness” of history here and now. And they do so through Hou’s very distinctive development of a filmic poetics of time, space, memory and the ordinary in order to enable the rethinking and re-presenting of history within popular culture. Key Words: Everyday Life, Representation, Memory, Time, Space, Trauma, History, Ethics of Witness, Poetics.Die vorliegende Arbeit untersucht die ästhetischen und ethischen Möglichkeiten, wie Geschichte und Alltagsleben in taiwanesischer Regisseur Hou Hsiao-Hsiens Filme filmisch präsentiert und gezeugt sind. Von der Zeit der japanischen Besatzung zum Weiße Horror und bis zur Zeit nach dem Ende des Kriegsrechts , möchte ich zeigen, wie Hou Hsiao-Hsien visuellen Medien nutzte, um den Rhythmus des täglichen Lebens durch die emotionale Erinnerung an den Charakteren und Gemeinden zu evozieren. Im Besonderen konzentriere ich mich auf die Art und Weise, wie er die starke Dilemmata der Identität und die traumatischen Gefühle von den Zeugen nachdenkt und darstellt. Zu diesem Zweck untersuche ich in dieser Dissertation die Filme von Hou Hsiao-Hsien und stelle dann die Frage dar: “Welche Mittel stehen zur Verfügung, für einen Filmregisseur es zu erforschen und so ein historische Ereignisse und Beobachtungen in einen Film zu integrieren?”, “Wie funktioniert die Kameraarbeit in der Erzählung über solche historischen Ereignissen?", "Was ist die Rolle des Films bei der Beleuchtung zu Gründen der Wahrheit - sagen die zeitgenössischen Ethik der besonderen Geschichte” “Wie dstellt die Filme die historische Trauma und die persönlichen Erinnerungen dar, die mit diesem Trauma gehen? Um diese Fragen zu beantworten, in Bezug auf die Werke des Filmemachers Hou Hsiao-hsien, stelle ich einige der formalen Praktiken zu demonstrieren, sowohl historische Verantwortung im allgemeinen und auch eine zuverlässige "Ethik des Zeugen” im besonderen. Ich behaupte, dass für eine bessere Verständnis für Hous Filme eine Art des Analyses wir überwinden müssen, die von der kritische Theorie dominiert wird. Im Gegenteil, wir sollen die individuelle Erfahrung und dessen die Beziehung mit der Geschichte und kollektive Erinnerung untersuchen. Ich behaupte also auch, dass Hous Filme haben über eine Phantasie gegangen, die die Geschichte und Erinnerung als Hintergrund verwendet. Im Gegentiel, seine Films möchten die Macht und die Autorität der “voice-over” der “offiziellen” Geschichte dekonstruieren. Als solche, Hous Filme nicht einfach aufnehmen die Erinnerungen der Vergangenheit, sondern verchen, dass sie sich ein Teil der ganze Ethik der Zeugnis der Geschichte ‘hier und jetzt’ werden. Und sie gewinnen es durch Hous sehr ausgeprägte Entwicklung seiner filmischen Poetik von Zeit, Raum, Erinnerung, und Alltagsleben. Diese künstlerische Tätigkeit ermöglichen das Nachdenken und Repräsentation der Geschichte innerhalb der populären Kultur. Stichwörter: Alltagsleben, Repräsentation, Erinnerung, Zeit, Raum, Trauma, Geschichte, Ethik der Zeugnis, Poetik.V, 288 Seite

Analytical modeling of an autonomous vehicle storage/retrieval system.

Automated vehicle storage/retrieval system (AVS/RS) technology is relatively new. It has been applied successfully in several European facilities in 1990s. AVS/RS is a flexible system that is a viable alternative to automated storage/retrieval systems (AS/RS), a traditional material handling technology that has been in existence for more than fifty years. There are very few papers in the literature that focus on the use of analytical models for estimating performance measures of AVS/RS. In this thesis, queuing network theory is used to model an AVS/BS system to analyze its performance. The manufacturing system performance analyzer (MPA) is an open queuing network (OQN) analyzer based on the parametric decomposition method. This thesis models the AVS/RS and uses MPA to analyze the performance of an AVS/RS configuration. A simulation model based on discrete events is also generated by Promodel to allow comparison of MPA results with those of simulation. A web interface for conceptualizing AVS/RS and AS/RS designs is presented in this thesis. This on-line tool provides a convenient and friendly interface between warehouse designers and time analytical model tool. Pour case studies of algorithms embedded in the web interface are presented in the thesis. An initial warehouse design is first analyzed by MPA. After this, several improvements of this initial design are evaluated. Experimental results are provided to show that the OQN methodology can he applied effectively to analyze an AVS/RS when vehicle utilization is between 60% and 85%. MPA is a better choice than simulation to quickly evaluate alterilate configuration of the AVS/RS. Additionally, two more experiments are conducted to compare MPA with another AVS/RS system performance analyzer. MPA models AVS/RS under the tier-captive configuration, whereas the other model assumes the tier-to-tier configuration