Imperial Terrains: Decolonization, Nationalisms and Diasporic Interventions in Diaoyutai Movement

王穎（加州大學聖地牙哥校區文學系）

 

http://www.cultural-typhoon.org/

 

透過重訪1969-72年席捲北美台灣留學生與台灣本島學生的保釣運動，本論文試圖論證兩點：其一，美國在冷戰時期對東亞無孔不入的干預，迄今猶有諸多空白等待結構性與歷史性的釐清；其二，戰後台灣在戒嚴前後由官方授意的國族史論述，實際上在對立與互補之間產生了許多問題，需要嚴肅細心地面對。本文藉由閱讀整理太平洋兩岸台灣學生保釣運動當時與事後的出版品、文學創作、自傳與回憶錄、座談發言等文獻，比較了北美和台灣兩地運動在背景和策略上的分歧，而正是在此一脈絡下，本文分析美國在冷戰時期所扮演的多重角色（尤其是帝國霸權的角色），如何顯著影響了太平洋兩岸與海峽兩岸對於「中國」的形塑與表述。進一步，本文指出，當今史論對於二戰之後渡海移植的中華民國與中共所建的中華人民共和國，或者對論戒嚴前與後的台灣，往往襲用既成二元框架，失之粗糙簡化，其中許多癥結顯見於當今台灣對於釣運同時並存的無感失憶與片面追憶之中。對此，如何有效介入權力與知識的循環使力，顯然是知識分子沈重而久遠的責任。

 

With the case of a phenomenal but ephemeral student movement that mobilized thousands of Taiwanese student in the US and at home to come to defense of Diaoyutai Islands from 1969 to 1972, this paper takes questions of the un(der)recognized powerful American presence in  Cold War East Asia and of interlocking problems constituted by state-endorsed national histories dominating postwar Taiwan. Revisiting how and why the movement erupted in 1969 across several cities and college towns in the US, and comparing differences of agenda and tactics between the transpacific interventions, the paper argues the multiple roles played America have significant impacts on varied formations of "China" across both the Pacific and Taiwan Strait. In reflections of the man-made bifurcations imposed on Chiang Kai-shek's transplanted Republic of China and Chinese Communist Party's establishment of People's Republic of China, Taiwan during and after Martial Law Period (1949-87), the presently coexisting oblivion to as well as partisan remembrance of Diaoyutai movement suggest many efforts are yet to be taken for coping with problems caused by the circular reinforcement of power and knowledge.

 

Vascular Fluid-Structure Interaction: Methodology and Application to Cerebral Aneurysms

論文發表人: 徐銘辰 (加州大學聖地牙哥分校結構力學所博士班)

http://usnccm-10.eng.ohio-state.edu/

近年來隨著影像擷取、模型製作、網格產生、計算方法以及視覺化技術的進步，針對特定病患之血流計算模擬也步入成熟階段。當今學界最先進之血管流計算研究為利用對大範圍人體心血管系統之流固耦合模擬，探索心血管疾病肇因進程與血液動力學之聯繫，預測外力介入之結果，並評估電子輔助醫療器具之影響。以上例子包含腹部及腦部之腫瘤模擬，及血管內硬化斑塊之形成與破裂。

本論文針對特定病患中大腦動脈分枝腫瘤進行計算模擬探討。我們提出一流體與固體結構完全耦合之模擬方法，並呈現支持此分析之網格生成技術。此流固耦合計算架構可預測實驗所無法獲得之血液動力數據並進行評估。我們並將其與純流體計算結果做比較，以分析於心血管計算模擬中考慮管壁彈性之重要性。

結果顯示血液與血管壁之交互作用改變了血液動力對管壁之施力。當心臟收縮血液流進腫瘤並衝撞管壁時，考慮管壁彈性將降低腫瘤內壁面剪應力並改變其分布。此結果彰顯了於針對病患之腦腫瘤計算模擬中，流固耦合之重要性。

In recent years patient-specific modeling of blood flow has matured immensely with the emergence of better imaging, modeling, mesh generation, computation and visualization technologies.
State-of-the-art vascular modelings involve fully coupled fluid-structure simulations of large portions of the human cardiovascular system, in an effort to investigate hemodynamic factors influencing the onset and progression of cardiovascular disease, to predict an outcome of an intervention, or to evaluate the effects of electromechanical assist devices. Examples of the first include
abdominal and cerebral aneurysms and formation and rupture of vulnerable plaque.

This work focuses on computation of several patient-specific aneurysm models at the middle cerebral artery (MCA) bifurcation. A fully coupled simulation approach is reviewed and main aspects of mesh generation in support of the fluid-structure analysis are presented.  Quantities of hemodynamic interest, that are unattainable in  experiments, are studied to assess the relevance of fluid-structure  interaction (FSI) modeling as compared to rigid-arterial-wall simulations.

The results show that the interaction between the blood flow and wall deformation changes the hemodynamic forces acting on the arterial wall. When the blood flows straight into the aneurysm and impinges the wall during the systole, the maximum wall shear stress (WSS) at the dome decreases while the effect of the flexible wall is incorporated in the computation. The resulting WSS patterns are altered both qualitatively and quantitatively. Rigid versus flexible wall simulation results reinforce the importance of FSI in the patient-specific modeling of cerebral aneurysms.

Motion Vector (MV) Search Window Prediction in Memory-Constrained Systems

羅仲成 (南加州大學電機所博士班)

 

http://spie.org/x30491.xml

 

動作估計是影像壓縮過程中，最消耗計算量的步驟。對於一張畫面中的Macroblock，家用電腦可使用相當大的搜尋視窗來尋找參考畫面中的動作向量。然而對於移動式裝置，可使用的快取以及處理器資源相當有限；因此為了避免快取失誤，適當的搜尋視窗大小必須列入考量。為了解決這個問題，我們使用統計方法分析每個Macroblock中搜尋視窗的位置、大小、以及形狀。我們並且基於系統對於畫質衰減的需求，估計一個適當的搜尋視窗位置、大小、及形狀。搜尋視窗的大小形狀以及畫質衰減之間的平衡也會在此討論。這些分析的結果可用來大幅提升再記憶體受限的移動式裝置中，動作估計的的效率。

 

除此之外，此一分析亦可運用在另外一種電腦架構──多核心處理器。在多核心處理器中，每個核心可運用的快取相當有限。除了受限的記憶體之外，為了最佳化多核心處理器的平行處理效能，許多Macroblock會同時在多核心中分散運算，這造成許多常用的空間關聯性在多核心系統中將無法繼續運用。所以，針對動作向量搜尋視窗的精確預測對於系統效能的提升有關鍵性的作用。

 

Motion estimation is the most computationally expensive task in video compression. For a given macroblock in the target frame, the search window of its motion vector (MV) in the reference frame can be quite large in the PC platform. In contrast, the available cache of the CPU is limited in mobile devices. Thus, it is important to fetch a proper search window of MV in the reference frame to avoid cache miss. To solve this problem, statistical analysis of MVs for search window location/size/shape prediction is conducted on each macroblock. A proper search window location, size and shape will be estimated while meeting a certain distortion requirement. Trade-off between the search window size/shape and distortion will be examined. These analytical results can speed up the motion estimation process in memory-constrained mobile devices.

 

There is another architecture that will benefit from the proposed technique, i.e. the multi-core processor. Besides a limited cache size for each core, many macroblocks will be executed simultaneously in multi-core processors to exploit parallelism to the maximum degree. As a result, some of the commonly-used spatial dependency may no longer be utilized as the motion estimation predictor. Thus, accurate prediction of MV search window is also critical to the system performance.