52,788 research outputs found
robust template matching using multiview video for head modeling
No full textrobust template matching using multiview video for head modeling. fu-che wu. murphy chien-chang ho. ming ouhyoung. department of computer science & information engineering. national taiwan universit
Gahrliepia (Gateria) minuta Chung, Wu, Kuo and Wang 2015
No full textGahrliepia (Gateria) minuta Chung, Wu, Kuo and Wang, 2015: ORIPublished as part of Nielsen, David H., Robbins, Richard G. & Rueda, Leopoldo M., 2021, Annotated world checklist of the Trombiculidae and Leeuwenhoekiidae (1758 - 2021) (Acari: Trombiculoidea), with notes on nomenclature, taxonomy, and distribution, pp. 1-243 in Zootaxa 4967 (1) on page 26, DOI: 10.11646/zootaxa.4967.1.1, http://zenodo.org/record/474551
The political role of the people's liberation army 1949-1973
No full textThis thesis is to study the political role of the People's Liberation Army from the approach of structure and function. The framework of the thesis consists of three major parts, first, the influence of Chinese traditional political culture on, and the formation of, the political role of the PL A; second, the influence of domestic political struggles and external military conflicts on the development of the political role of the PLA; and the third, the analysis of the transition of the PLA's political role from the structure and personnel arrangements of the CCPCC Within the above-mentioned three scopes, this thesis make a thorough discussion on the following: (1) The relationship between the structure of the PRC and the formation of the PLA's political role; (2) How has ideology influenced the army's political role; (3) What is Mao's viewpoint and his influence on the development of the army's political role; (4) What is the link between the army and the party, and how has this developed; (6) What accounts for the expansion of the PLA's political functions; (7) What is the influence of political factional struggles on the PLA's political role; (8) Is it political institution or military institution that controls the recruitment of the military elite; (9) What are the disparities between the military elite in handling international conflicts and what are their political considerations; (10) What is the Party's position in the army; (11) How have the Party’s important meetings and personnel arrangements influenced the rise and fall of the PLA's political role
What Can Cryptography Do for Decentralized Mechanism Design?
No full textRecent works of Roughgarden (EC'21) and Chung and Shi (SODA'23) initiate the study of a new decentralized mechanism design problem called transaction fee mechanism design (TFM). Unlike the classical mechanism design literature, in the decentralized environment, even the auctioneer (i.e., the miner) can be a strategic player, and it can even collude with a subset of the users facilitated by binding side contracts. Chung and Shi showed two main impossibility results that rule out the existence of a dream TFM. First, any TFM that provides incentive compatibility for individual users and miner-user coalitions must always have zero miner revenue, no matter whether the block size is finite or infinite. Second, assuming finite block size, no non-trivial TFM can simultaneously provide incentive compatibility for any individual user and for any miner-user coalition.
In this work, we explore what new models and meaningful relaxations can allow us to circumvent the impossibility results of Chung and Shi. Besides today’s model that does not employ cryptography, we introduce a new MPC-assisted model where the TFM is implemented by a joint multi-party computation (MPC) protocol among the miners. We prove several feasibility and infeasibility results for achieving strict and approximate incentive compatibility, respectively, in the plain model as well as the MPC-assisted model. We show that while cryptography is not a panacea, it indeed allows us to overcome some impossibility results pertaining to the plain model, leading to non-trivial mechanisms with useful guarantees that are otherwise impossible in the plain model. Our work is also the first to characterize the mathematical landscape of transaction fee mechanism design under approximate incentive compatibility, as well as in a cryptography-assisted model
Justification of installing 4GL in Hong Kong environment.
No full textby Wu Chung Man, Ronnie.Thesis (M.B.A.)--Chinese University of Hong Kong, 1988.Bibliography: leaves 43-45
Fracture Tests and Finite Element Analysis of Diaphragm Connection in Steel Beam-to-Box Column Joints
No full text因鋼箱型斷面柱構件雙強軸的特性，所以在國內鋼建築結構中應用非常普遍。為傳遞梁端彎矩至柱構件，箱型柱內與梁翼同高處須配置與梁翼同厚的橫隔板。內橫隔板與柱板間之銲接常使用電熱熔渣焊(Electro Slag Welding, ESW)之工法，此種焊道施作便利及效率高，目前已大量使用於國內鋼結構製造廠。然而，ESW在施做時的高入熱量恐導致其焊道結晶過大與抗衝擊性質較差，此現象亦常導致梁柱發生非預期的脆性破壞。林克強等人(2008)針對此銲接細節進行22組之梁柱接頭試驗，試驗結果發現，當接頭尚未發展明顯非線性變形前，常在ESW銲道之熱影響區(HAZ)附近發生脆性破壞，其破壞機率約為18%。鄭元良(2011)承接林克強(2008)之試驗結果進行ESW元件試驗，實驗結果顯示ESW偏心與梁翼板高程偏心對於整體反應影響甚大。本研究為避免ESW發生脆性破壞及量化ESW破壞之機制，引用Kanvinde (2004)建議之鋼材斷裂預測模型，利用有限元素模型對試體進行斷裂預測分析。 本研究延續鄭元良(2011)之梁柱接頭試驗，另外進行兩組試驗，藉由變化試驗之載重歷時與ESW之施工儲倉口截面形狀，探討試體之破壞時機並驗證鋼材斷裂預測模型之可行性。實驗結果顯示，標準型載重歷時與增加型載重歷時之破壞時機分別在目標位移角為3%弧度之第2迴圈及第1迴圈，證實累積塑性應變大小確實影響其破壞時機；ESW儲倉口截面由矩形變為與喇叭口形時，破壞時機在目標位移角為3%弧度之第2迴圈位置在ESW之熱影響區，轉變為破壞在4%弧度第1迴圈位置在梁翼焊接之熱影響區，顯示若增加ESW之熔透範圍可增加接頭試驗耐震性能。 為應用斷裂預測模型，本研究藉圓周刻痕拉伸(CNT)試驗與有限元素模型分析，將所得之材料參數對ESW元件試驗與梁柱接頭試驗進行斷裂預測分析。分析結果顯示， ESW之幾何形狀及相對位置對於破壞時機影響甚大，精確之分析模型可有效預測破壞之位置與時間，因此顯示破壞預測分析與CNT試驗之可行性，以及銲道超音波檢測(UT)之重要性。經由實驗與分析所得之結果，本研究進行ESW相關幾何位置之參數分析，藉由ESW銲道之垂直偏心與水平偏心對應不同梁翼板之偏心情況，共建立45組有限元素模型，並預測破壞之時機。分析結果顯示ESW關鍵區域之大小確實為影響破壞時機之主要原因，且當梁翼板與ESW成垂直反向偏心時，破壞時機最早發生，因此擴大ESW關鍵區域可有效的降低ESW破壞之發生，也證實儲倉口截面為喇叭口形可增加其耐震性能。Steel box columns are widely used in steel building structures in Taiwan because of the strong axes in two directions. In order to transfer the beam end moment to the column, diaphragm plates of the same thickness and elevations as the beam flanges are usually welded inside the box column. The electro-slag welding (ESW) process is usually used in attaching the diaphragms to the column flanges. This ESW process has been widely used in steel beam-to-box column joints in Taiwan because of its’ convenience and efficiency. However, the ESW may increase the hardness of the welds and heat affected zones (HAZs), while reduce the Charpy-V Notch (CVN) strength in the HAZ. This situation could cause the diaphragm to column flange weld to suffer premature fracture before a large plastic rotation is developed in beam-to-box column joints. Results of 22 full scale steel beam-to-box column connection tests conducted in 2008 by Lin et al. show that the probability of ESW fracture at the HAZs adjacent to the ESW is about 18%. Cheng et al. continued the study in 2011 with new tests on full scale beam-to-box column subassembly and ESW components. Test results show that the fractures of the diaphragm-to-column flange welds are sensitive to the eccentricity between the elevations of the ESW and the beam flange. In order to quantify the critical eccentricity and the effectiveness of predicting the fractures, this study adopts the fracture prediction model proposed by Kanvinde in 2004 and utilizes finite element model (FEM) analysis to correlate the test results. In this study, two additional beam-to-box column connection subassembly tests have been conducted with a different loading protocol or the shape of ESW chamber. It is found that the fractures of the aforementioned HAZs can be reasonably well predicted using the proposed procedures on applying the fracture model. Test results show that under the standard and increasing loading protocols, the instances of the HAZ fractures in the specimens correspond to the total beam end deformations of the 2nd and 1st cycles of 0.03 radian, respectively. It is confirmed that the fracture instances can be predicted based on the cumulative plastic deformation in the HAZs. Under the two same standard loading protocol, the flared ESW chamber alter the fracture location from the HAZ in the diaphragm weld to the beam flange weld, and delay the fracture at the 2nd cycle of 0.03 radian to the 1st cycle of 0.04 radian. Tests confirm that the possible fracture of the diaphragm to column flange welds can be mitigated by enlarging the chamber of the ESW. When the fracture prediction model is applied, the material parameters were firstly established from the Circumferential Notched Tensile (CNT) tests and FEM analysis. Subsequently, these parameters were used to predict the fractures observed in the ESW component tests and beam-to-box column connection subassembly tests. The fracture locations and instances can be reasonably well predicted by a suitable FEM model analysis. Thus, the effectiveness of CNT and the fracture model are confirmed. Analytical results also show fracture instances and locations are sensitive to the relative locations of the ESW and the beam flange. Thus, the importance of ultrasonic test in assuring the quality of the ESW is evident. Finally, a parametric study on the eccentricity between the ESW and beam flange locations is conducted using 45 models with various vertical and horizontal eccentricities of ESW with respect to the beam flange. The parametric study results show that the size of critical zone of ESW is indeed the most important factor affecting the fracture instance. When the relative vertical eccentricity between ESW and beam flange is increased, the fracture instances is accelerated. Enlarging the critical zone of ESW effectively reduces the possibility of fracture as evidenced by using a flared shape ESW chamber in the aforementioned test specimen
Fast determination of coral skeletal rare earth elements in picogram quantities and its application
No full text本研究利用磁場式感應耦合電漿質譜儀(ICP-SF-MS)，建立一套測量珊瑚骨骼內稀土族元素之分析技術，其偵測極限可達皮克等級(picogram)。我們使用乾式霧化器導入系統，以增強訊號、改進偵測極限，和降低樣品需求量。本方法所量測的同位素包括46Ca、89Y、138Ba及各稀土族元素；稀土族元素和鈣的比值，是經由離子訊號強度比值(REE/Ca)直接計算而得。每四個樣品穿插一個基質成份相近的標準溶液，校正儀器的質量分化和比值飄移。本方法的之測量準確度可達到 0.4-1.4% ，標準溶液的長期重現性可達 0.8-1.6% (2σ)。 我們分析一顆於2005年，在南海西側、位於越南中部Son Tra島所採集到的珊瑚標本，發現其稀土族元素在1991年夏季至秋季，產生異常偏高值，鑭鈣比值(La/Ca)高達平常年的30-40倍；鐿鈣比值(Yb/Ca)為平常年的2-4倍。推論造成該年夏季南海海域珊瑚大規模死亡的原因，與當年6月15日鄰近的菲律賓皮那土波火山(Mt. Pinatubo)大爆發所帶來大量火山灰有關，造成珊瑚生態系統死亡。 利用磁場式感應耦合電漿質譜儀所建立之珊瑚骨骼內稀土族元素之分析技術，最大優點在於不需經過繁複之化學處理步驟，可直接量測出極低含量（皮克等級）之稀土族元素。本方法的標本需求量僅為 10 μg，不僅可以提供高解析度之稀土族元素分析，將來可進一步應用於不同環境樣本，例如海綿、石灰華、石筍等之分析上，做為研究古環境之變化之極佳代用指標(proxy)。Direct measurement of picogram-quantity REE levels in coral samples on an inductively coupled plasma sector field mass spectrometer, ICP-SF-MS, Thermo Electron ELEMENT2, has been developed. A dry introduction system, Cetac ARIDUS, and an ESI micro-nebulizer with an uptake rate 80 μl/min were used to enhance sensitivity, improve detection limit and reduce sample size. A peak hopping mode on a single secondary electron multiplier was used to measure the ion beams of 46Ca, 89Y, 138Ba, 139La, 140Ce, 141Pr, 146Nd, 147Sm, 153Eu, 160Gd, 159Tb, 163Dy, 165Ho, 166Er, 169Tm, 172Yb, and 175Lu. REE/Ca ratios were calculated directly from intensities of ion beams, using external matrix-matched synthetic standards to correct for instrumental ratio drifting and mass discrimination. Every four samples were bracketed with one standard. Internal 2-sigma precision is 0.4-1.4% for all REE/Ca ratios. Replicate measurements made on standards and samples show external precisions of 0.8-1.6% (2σ) can be achieved. The developed was applied to determine REE records of a living coral Porites, collected from Son Tra island (16°12’59.4”N, 108°11’57.1”E), central Vietnam, western South China Sea (SCS) in 2005. The 1991 REE anomalies suggest that a massive mass coral mortality event in the summer and fall of 1991 in the SCS might be enhanced by the volcanic ash fallout following the eruption of Mount Pinatubo on June 15, 1991. This established technique can provide a direct measurement of carbonate REE isotopic composition in picogram quantities without chemical separation steps. The requirement of a small sample size of 10 μg carbonate offers high spatial resolution REE records not only for corals, but for other different natural slow-growth-rate carbonates, such as sclerosponges, tufa and speleothems.Table of Contents Iist of Figures IIIist of Tables V要(Abstract in Chinese) 1bstract 2hapter 1 Introduction 3hapter 2 Experimental Procedure 5 2.1 Environment 5 2.1.1 Chemistry 5 2.2 Standards 5 2.3 Instrumentation 7 2.3.1 MC-SF-MS (Element 2) 7 2.3.2 Introduction system 9 2.4 Data acquisition 10hapter 3 Results and Discussion 12 3.1 Spectral interference 12 3.2 Blank and memory effect 13 3.3 Isotopic ratio drifting and mass discrimination 15 3.4 Matrix effects 17 3.4.1 Acid effect 17 3.4.2 [Ca] effect 18.5 Measurement sequence 19 3.6 Long-term precision, accuracy and sample size 21 3.7 Advantages and disadvantages 24hapter 4 A case study: coral REE signature 26 4.1 Sample location and collection 26 4.2 Coral mortality in 1991 summer 27 4.3 Al/Ca anomaly 32 4.4 REE levels and anomalies 33 4.5 Comparing with in situ Mt. Pinatubo igneous rocks 35hapter 5 Conclusions 37eferences 38cknowledgement 4
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