64 research outputs found
Oxygen diffusion in active layer of aerobic granule with step change in surrounding oxygen levels
No full textSimulation Fidelity Theory and Practice
No full textSimulation fidelity is an intrinsic element of any simulation system, one that all its developers and users have to deal with one way or the other. It is commonly recognized by the modeling and simulation community that simulation fidelity is an essential vehicle in properly assessing the validity and credibility of simulation results. Furthermore, fidelity is one of the main cost-drives of any model or simulation development. Rigorous assessment of fidelity is, however, one of the most difficult and hard to grasp issues within the model and simulation community. Substantial and exhaustive research endeavors in this area are very limited. Due to this, simulation fidelity still remains a hardly touched upon and rather uncultivated area. This thesis tries to fill this void by the analysis, extension and integration of existing simulation fidelity approaches into a single unified fidelity theory and practice. All this is done from a general simulation system life cycle perspective, not limited by any specific application or problem domain aspects. The foundation for this developed unified fidelity framework comprises a precise mathematical formulation for fidelity and the fundamental concepts underlying its characterization and measurement. The unified fidelity framework is completed with a fidelity management process model outlining a series of generic stages, activities and tasks, which together provide a structured but generic approach to properly integrate and apply all other unified fidelity framework elements in the simulation system development and validation process.Aerospace Engineerin
A study of pseudo-random sequences
No full textFull text is available to authenticated members of The University of Auckland only.This thesis consists of two main sections:
1. Theoretical
Chapter One provides an introduction which gives the historical background and motivation of the study of pseudo-random sequences, as well as their classifications and general properties. A Survey of existing classes of pseudo-random sequences, definitions, and their boundary conditions, is given in Chapter Two. Five important classes of pseudo-random sequences are studied in detail in Chapters Three to Six. Two classes of Barker Sequences which have been modified by the author are given in Chapter Three. The concept of the “cyclic circle” is introduced by the author to link all multi-level pseudo-random sequences, and is used to study the properties of such sequences in Chapter Four. An explanation of how M-sequences may be obtained from the difference set, and two original methods of designing M-sequence generators are described in Chapter Five. A simplified explanation by the author of the concept of projecting maximal length sequences from m-space into a binary plane to generate Planar sequences is given in Chapter Six.
2. Practical
Chapter Seven discusses the design of sequential circuits. The concept of “structural matrix”, derived by the author, is defined and its application to the analysis, synthesis and simplification of synchronous sequential circuits is given. Chapter Eight discusses the design of high speed pseudo-random sequence generators. An original method of designing high-speed M-sequence generators, as well as a general algorithm for speeding up the generation of multi-level pseudo-random sequences are given. A selection of significant applications of pseudo-random sequences is discussed in Chapter Nine. The advantages of using pseudo-random sequences over conventional methods are described
(34(2):213-222)Introduction, Propagation and Liberation of a Pupal Parastoid, Tetraslichus brontispae, for the Control of the Coconut Leaf Beetle in Taiwan
No full text本所於民國72 年11 月自關島引進可可椰子紅胸葉蟲（Brontispa longissima）之蛹寄生蜂Tetrastichus brontispae Ferr. 供可可椰子紅胸葉蟲之防治。該蜂引進本省後先在本所檢疫室進行檢疫、飼育以及生物特性等觀察。經繁殖3 世代後即在高雄澄清湖與屏東林邊兩地釋放。農試所在室內飼育該蜂，發現其發育期之長短隨溫度之高低而有不同，於室溫20℃時，從卵發育至成蜂羽化，最短需17 天，最長達32 天。各蟲期分別為卵期2-3 天，幼蟲期5-6 天，蛹期10-11 天。平均雌蜂壽命約10.8 天，雄蜂約3.6 天。初步飼育觀察該蜂在室內之產卵寄生率平均為60.13 ±8.0 %。T. brontispae 蜂於民國72 年1 月18 日開始，先後10 次釋放於澄清湖畔之椰樹林，至同年8 月其寄生率為18.8-79.2 %。另於同年2 月8 日釋放於林邊，在3 個月內釋放7 次其寄生率為9.3-44.2 %。該蜂在兩地之釋放後均能寄生於紅胸葉蟲之蛹，順利繁衍，而發揮其生物防治效果，使受害之可可椰子樹逐漸恢復生機。本文報導該蜂之引進本省經過，室內增殖、部分生物特性觀察及其釋放於高、屏地區後，對可可椰子紅胸葉蟲棲群之抑制效果。
The coconut tree, Cocos nucifera L., grown in the tropical and subtropical regions of the world, is the best known palm with high economic values. In Taiwan, it can be grown on the east coast and in areas south of Taichung on the west. The number of coconut trees planted in 1960 was estimated at 12,000 trees and was gradually increased to a total of 60,000 trees in 1984.
The coconut leaf beetle, Brontispa longissima Gestro (Chrysomelidae), a serious pest of coconut trees, was first detected in Pingtung in July 1975. Since then, it has spread north to Taitung and then to Hualien. Since coconut trees are tall, reaching a height of 15-20 m., and are commonly planted along highways and around fish ponds, it renders the use of chemical pesticides for control of this pest economically impractical and environmentally unsafe. Therefore, the biological control approach was chosen as a viable alternative for solving this serious pest problem.
Through the cooperative efforts of Dr. R. Muniappan, University of Guam, Tetrastichus brontispae Ferriere (Eulophidae), was field collected and shipped to Taiwan. The first shipment of B. palauensis (Esaki and Chtjo) parasitized by T. brontispae was received via air mail on November 3, 1983 and the second shipment was hand delivered on November 5, 1983.
Upon receipt, the shipments were screened and studied in a quarantine laboratory at Taiwan Agricultural Research Institute. The packing material was autoclaved at 120°C, 15 PSI for 30 mm. and discarded. B. palauensis adults which had escaped parasitization by T. brontispae were also destroyed by autoclaving.
Under the room temperature of 21°C, T. brontispae required 17 to 32 days to complete its life cycle from egg to adult. The durations of egg, larval and pupal stages were 2 to 3, 5 to 6, and 10 to 11 days, respectively. The longevity of adult male and female was 3.6 and 10.8 days, respectively.
T. brontispae is a pupal parasitoid which apparently preferred to oviposit in one- day old pupae of B. longissima. The average percent parasitism in the laboratory tests was 60.1±8.0%.
After three generations had elapsed under tightly controlled quarantine conditions,T. brontispae was field released at coconut patches in Chenchinhu and Linbien. A total of 10 releases of 11,456 T. brontispae adults in Chenchinhu was made during January-July 1984 and seven releases of 4,881 adults in Linbien during February-June 1984. The percent parasitism recorded from field recoveries made in Chenchinhu and Linbien was 21.2 to 79.2% and 9.3 to 36.2%, respectively.
The population dynamics of B. longissima was also investigated at both Chenchinhu and Linbien. Based on the comparison of the pre- and post-release data, the results showed that the population densities of B. longissima in Chenchinhu fluctuated from an average of over 190 larvae per plant to 60 larvae per plant during September-December 1983. However, after the release of T. brontispae in January 1984, the population densities of B. longissima were kept below an average of 40 larvae per plant, except April and May 1984 , when there was an upsurge of B. longissima. This upsurge was subsequently suppressed after 4 releases of T. brontispae to a level with less than 10 larvae per plant during August-December 1984. A similar trend of this population fluctuation at much lower levels was also observed on B. longissima adults. This indicated that T. brontispae prevented the majority of larvae of B. longissima from developing into adults.
In Linbien, however, T. brontispae appeared to be unable to suppress B. longissima populations. Although the percent parasitism ranged from 15 to 40%, the effectiveness of T. brontispae at this location remains unproven and further studies will definitely be needed.
The ability of T. brontispae to disperse in field conditions was demonstrated when it was repeatedly recorded at Niaushun, Fengshan, Wujaen and Tashue, approximately 2 to 8 km from the release site in Chenchinhu. Hence, it strongly indicates that T. brontispae has become well established in Taiwan and gradually dispersed by itself among coconut growing areas. It also indicates that T. brontispae does possess the desirable attributes in host searching and dispersal to become an effective biological control agent of B. longissima
Finite difference methods for stress analysis of adhesive bonded joints; the design of a MATLAB adhesive toolbox
No full textPlaying in the light
No full textFrom the acclaimed South African novelist, a lyrical tale of self-discovery in post-apartheid cape town. Set in a beautifully rendered 1990s Cape Town, Playing in the Light revolves around Marion, a woman of Afrikaner background, who hates traveling but nonetheless runs a travel agency, and her complex relationship with Brenda, the first black woman she has ever employed. In writing as finely detailed and attuned to psychological nuance as Anita Brookner's, Wicomb depicts the life of a complicated, single woman in a changing and complicated place. Caught up in the narrow world of private interests and self-advancement, Marion eschews national politics until the exposures of the Truth and Reconciliation Commission lead to the discovery of a skeleton in the family cupboard. While her aging father is unable and unwilling to supply the truth, Marion's young employee becomes implicated in the piecing together of Marion's past, leading to a defining transformation and widening of Marion's world. In this impeccably wrought new work, the acclaimed author of You Can't Get Lost in Cape Town provides wisdom and insight about the new South Africa and about people everywhere
An explanation of happiness with secure attachment, basic psychological needs and hope: The case of Turkish university students
No full textIn this study we aimed to investigate the role of hope, secure attachment with the parents, and satisfaction levels of the basic psychological needs (autonomy, competence and relatedness) of university students in predicting their happiness levels. A total of 558 university students were recruited and 70% of them were female and 30% of them were male. Ages of the participants ranged from 18 to 29. The data were collected in classroom settings using personal information form, the Oxford Happiness Scale, the Attachment with the Parents Scale, the Basic Psychological Needs Scale, and the Dispositional Hope Scale. Results indicated that that the satisfaction levels of the competence needs were the most powerful predictor of happiness among university students. The satisfaction levels of autonomy, relatedness needs, and a secure attachment to the father, along with hope contributed little to the explanation of happiness; whereas, a secure attachment to the mother was not a predictor of happiness of the university students. The findings were discussed within the framework of the developmental characteristics of university students and the characteristics of collectivist societies. © 2020 The Author(s
Predicting the yield stress of 3D printing mortar based on the flowability of paste and excess paste thickness
No full textThis paper develops an empirical model to predict the static yield stress of 3D printing mortar based on the flowability of paste and excess paste thickness. The components of the mortar are divided into paste and aggregate. The relation between the yield stress of mortar and the yield stress of paste and the excess paste thickness is investigated. It is found that there is a linear relationship between the yield stress of mortar and that of paste, and the yield stress of mortar also is proportional to the reciprocal of excess paste thickness. Additionally, the yield stress of paste is related to its flowability when the rheological behavior of mortar is modified with different types and dosage of thixotropic agents. Based on the experimental data, an empirical model is built to predict the static yield stress of mortar in accordance with the flowability of paste and excess paste thickness
Oxygen diffusion in active layer of aerobic granule with step change in surrounding oxygen levels
No full text10.1016/j.watres.2006.11.035Water Research414884-892WATR
Oxygen diffusion and consumption in active aerobic granules of heterogeneous structure
No full text10.1007/s00253-007-0847-6Applied Microbiology and Biotechnology753685-691AMBI
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