台灣留學生出席國際會議補助

2007年11月20日 星期二

Optimizing 0/1 Loss for Perceptrons by Random Coordinate Descent

論文發表人:林軒田 (加州理工學院電腦科學所博士班)

http://www.ijcnn2007.org

0/1 損失是感知器的一個重要的成本函數。然而,現有的感知器學習演算法無法輕易的對這個函數最佳化。在本文中,我們提出隨機坐標減少演算法來直接最佳化 0/1 損失,並證明其收斂性。本演算法計算效率較其他演算法為高,而且通常可得到最低的 0/1 損失。這種優勢,使之有助於解決真實世界中的非線性分割問題。實驗表明,本演算法對集成學習特別有幫助,配合增強集成學習演算法後,可在許多複雜的資料上得到最佳的測試結果。

The 0/1 loss is an important cost function for perceptrons.  Nevertheless it cannot be easily minimized by most existing perceptron learning algorithms. In this paper, we propose a family of random coordinate descent algorithms to directly minimize the 0/1 loss for perceptrons, and prove their convergence. Our algorithms are computationally efficient, and usually achieve the lowest 0/1 loss compared with other algorithms. Such advantages make them favorable for nonseparable real-world problems. Experiments show that our algorithms are especially useful for ensemble learning, and could achieve the lowest test error for many complex data sets when coupled with AdaBoost.

Geographic distribution and genetic diversity of Waitea circinata var. circinata isolated from annual bluegrass in the U.S.

 
論文發表人: 陳其敏 (加州大學河濱分校植物病理所博士班)

http://meeting.apsnet.org/default.cfm

在美國高爾夫球場草坪樣本中分離出Waitea circinata var. circinata (Wcc) WccRhizoctonia的有性世代之一, Rhizoctonia spp能感染禾本科葉部或根部造成植株死亡 早熟禾屬的annual bluegrass (Poa annua)草種在美國被廣泛的用於草坪植被例如高爾夫球場 實驗用菌株包括從加州, 康乃迪克州, 伊利諾州, 緬因州, 內華達州, 紐約州, 奧勒岡州, 羅德島以及華盛頓州分離而得 經過形態鑑定以及rDNA ITS分子鑑定(RFLP, Restriction fragment length polymorphism)確定引起病害的真菌是Wcc 然而rDNA ITS經過酵素(Hap II)脢切後少數菌株在電泳圖上顯示三個DNA片段, 有異於前人研究的兩個片段 研究顯示未被酵素脢切的第三個片段之尺寸約為rDNA ITS全長 經過序列解析以及基因選殖, 發現在酵素作用位置上此真菌發生突變或是經由遺傳導致同一株菌系中同一個核酸位置擁有兩種不同的核酸導致酵素無法辨識進行脢切此研究顯示此真菌的ITS雖然有約2%的多樣性,但是仍足夠用以分辨此真菌與其他同樣是Rhizoctonia spp且能在禾本科上引起病害的不同種類 同時,此研究也彰顯出此真菌在美國是廣泛分布,而不僅僅如同前人研究所指只分布於美國西岸

Waitea circinata var. circinata (Wcc), is the causal agent of brown ring patch of Poa annua that was recently discovered in the U.S and it is also a pathogen on Agrostis stolonifera in Japan. 42 isolates were identified as Wcc based on colony morphology and RFLP method using HapII. Some of the isolates produced two bands whereas others produced three bands. Sequencing the ITS rDNA confirmed that few isolates have heterozygous at the HapII restriction site. The sequencing reactions failed which was due to two indels at poly T positions. Intra-species variability in the ITS was low but phylogenetic analysis clearly separates Wcc from other varieties. It indicates that Wcc is wide spread across the U.S. as a pathogen of Poa annua.

Pre-modern meets Post-modern in Environmental

論文發表人:汪俊彥 (加州大學洛杉磯分校 戲劇批判理論研究所博士班 )

 

http://www.athe.org/

 

  一九八零年代,「環境劇場」的理論與實踐由理查謝喜納介紹到了台灣。如 同一位台灣戲劇學者所述,一九八零年代的台灣所受的歐美戲劇影響可以視為中國戲劇在二十世紀以來的第二次的西潮。這篇論文起源於以下的問題意識:我們應該如何詮釋這場二次西潮在中國現代戲劇的影響?這二度西潮是否重複了第一次西潮所造成的中國與「西方」劇場的權力傾斜?

 從二次西潮中的兩齣劇場表演出發,一則可以視為「後現代」表演,另一則則可名為「前現代」的演出,兩者均或多或少受到理查謝喜納的理論與實踐影響而誕生,本篇論文將透過以上兩個例子,以理查謝喜納在台灣的理論與實踐情形,觀察台灣現代戲劇的二度西潮。

為了理解二度西潮的現象,本篇論文先初步檢視中國戲劇的第一次西潮。第一次西潮,簡單說,「發明」了中國現代戲劇,掌握了戲劇的現代性,並且巨大地改變了中國傳統戲曲。

 在簡單對第一次西潮的歷史痕跡回顧之後,論文指出在二次西潮巨麾之下,由理查謝喜那的學生鍾明德,一位在台灣任教同時進行戲劇實踐者,所倡導的「後現代」戲劇,在面對西方戲劇的霸權時,並沒有提供一種「去中心式」的後現代結構觀。也就是說,如果後現代主義提供了一種對中心與霸權的解構態度,本篇論文想要問,並且試圖解決的是:在西方霸權的既存結構下,究竟有沒有所謂普遍性的「後現代」的劇場?我們又如何能透過環境劇場,連結「前現代」的文化資源,一種本文認為具有「本土性」的特質,來「重建」中國的現代劇場?

 

 Around the middle of the 1980s, the notion of environmental theatre as theorized and practiced by Richard Schechner was introduced to Taiwan. As one theatre scholar in Taiwan remarked, the influence of theatrical practices from European and American contexts in Taiwan in the 1980s can be regarded as the second "Western Wave" (Xi-Chao) in the history of Chinese theatre in the twentieth century.     This paper arose from the question: How should we interpret this second Western Wave in the modern history of Chinese theatre? Does it repeat the pattern of the first wave, which evokes images of unbalanced power relations between China and "the West?"

 Using two examples of "post-modern" and "pre-modern" performances in the second Wave, both of which were influenced by Richard Schechner and the theory of environmental theatre, this paper tries to analyze the second wave of Western theatre and Richard Schechner's environmental theatre in theory and practice in Taiwan.

 In order to understand how the second Western wave influenced modern Chinese theatre, we first need to examine the first wave of Western Chinese theatre.  The first Western wave, to some extent, "invented" Chinese modern theatre, manipulated ideas of theatrical modernity and changed the traditional Chinese music drama in significant ways. 

 After a brief discussion of the historical legacy of the first Western wave, I will indicate that under the rubric of the second "Western Wave," the acclaimed "post-modernist" environmental theatre as advocated by theatre activist and scholar Chung Mingde ,who was a student of Schechner at NYU, might not have succeeded in providing a "de-centered" theatre in terms of the Western dominance of theory.

 In other words, if the contribution of post-modernism has helped to deconstruct the norm of the center, I would like to raise the question of whether a purely "post-modernist" performance existed, in terms of theory and practice in environmental performances under the second Wave. How could we remake a Chinese modern theatre in the form of environmental theatre with reference to pre-modern performances, which I argue embodies a kind of locality?

 

User Access of Public Shared Devices in Pervasive Computing Environments

論文發表人:  賈德勤 (加州大學洛杉磯分校電機所博士班)

http://healthnet07.cs.uiuc.edu/

在普及運算的環境下, 我們預計儀器和感測器是可以被許多人所共用存取的, 那要讓使用者簡單有效地使用某項儀器或感測器, 可靠及方便的認證是非常重要的條件. 這個問題將變得更複雜, 如果考量使用者與其他多人在同一鄰近區內, 並且要同時存取多個不同的儀器. 本篇論文首先從存取的三個先後階段(登入, 偵測並保持連結, 登出)下去探討, 要建立連結到這樣一個儀器所需要面對的問題. 本篇論文的主要貢獻在於我們辨別了一般在使用者存取儀器時的常見陷阱: 取得對一個儀器的控制存取的方式, 並不一定要和維持這個存取連結的方式相同, 也不需要和釋放存取控制這個儀器的方式相同. 另外, 當使用者連結到一個儀器時, 並不代表這個使用者正實體上在使用這個儀器. 文內接著提出一個改進後的情境感知方法, 藉由判別使用者身處的情境以及所要連結的儀器的狀態, 來判定並允許使用者和公用儀器間建立一個安全, 易用, 可選擇, 和可辨別的存取.   

To allow for an efficient usage of a device in pervasive computing environments when a user intends to selectively utilize multiple devices within his/her vicinity, reliable and yet convenient authentication is an important requirement. The problem becomes more complex when the accessed device is shared by the public with many different individuals. This paper first illustrates the issues of establishing sessions to such devices (logging in, maintaining a session, and logging out), and then identifies the common pitfall of access-control contexts. We propose an improved context-aware solution that supports a secure, selective, and identifiable user access of public shared devices with high usability.  

Controlled Growth of Quantum Dots and Nanopillars on Patterned GaAs Substrate by MOCVD

論文發表人:翁秉秀(新墨西哥大學光電所博士班)

 

http://www.tms.org/Meetings/Specialty/EMC07/home.html

 

本篇論文中,我們報告了以區域選擇性之奈米磊晶生長定址量子點及奈米柱。我們首先探討砷化銦量子點在砷化鎵金字塔結構奈米晶面上之選擇性結晶成核。此方式成長之量子點,其形狀和大小均較Stranski-Krastanow成長模式易於控制。砷化鎵金字塔結構是以金屬有機化學氣相沉積術在由二氧化矽定址之(001)砷化鎵基板上生長。圓形的定址區域是由干涉式微影術形成。砷化鎵金字塔結構由包含了{11n}{10n}(001)等三個晶面族的平衡晶體形狀組成。接下來的定址量子點結晶成核高度偏好(11n)平面,這是由於該平面提供較佳之能量最小化。在(11n)平面上形成之量子點的形狀十分容易預測,也十分均勻。這些砷化鎵平衡晶體形狀及高度晶面化之量子點均由高解析度之掃描式電子顯微鏡來分析。我們並且展示了常溫下之熒光光譜及電激發光譜,範圍在1.21.6微米之間。低溫的熒光光譜也證實了三維量子限制的存在。

同樣的定址方法也用於在砷化鎵(111)B基板上生長砷化鎵奈米柱。此方式提供較佳之均勻度及奈米柱之分布,同時還有簡易之電極接觸模式,因此是製作奈米電子元件一個有吸引力的方式。在這個研究中,奈米柱的生長在不同的生長條件下進行。這些奈米柱形成了高度結晶化、由(001)(011)側面所包圍的六角截面。微熒光光譜及電氣特性也同時被檢視。

 

We report selective area nano-epitaxy to form both patterned quantum dots (PQDs) and nanopillars.  The selective InAs quantum dot (QD) nucleation on nano-faceted GaAs pyramidal facets is explored. This technique of QD growth enables better control of QD shape and size, than is possible with the Stranski-Krastanow (SK) growth mode. The GaAs pyramids are formed by metal-organic chemical vapor deposition (MOCVD) in patterned SiO2 mask on a (001) GaAs substrate. The patterning is done by interferometric lithography and the circular patterns in SiO2 are 25 nm deep and 230 nm in diameter, with a pitch of 330 nm. The GaAs pyramids are characterized by well-defined equilibrium crystal shapes (ECS) defined by three crystal plane families including {11n}, {10n} and (001).  Subsequent patterned QD (PQD) nucleation on the GaAs pyramidal facets is highly preferential towards the (11n) planes due to superior energy minimization and the shape of the QDs on the (11n) planes is also highly predictable and uniform.  The GaAs ECS pyramid and highly faceted PQDs are examined using high-resolution scanning electron microscopy (HRSEM), and room temperature photoluminescence (PL) and electroluminescence from 1.2 to 1.6 µm has been demonstrated. Three dimensional quantum confinement is confirmed with low temperature (77K) PL. 

The same lithographically defined patterns are used in the development of GaAs and GaSb nanopillars on GaAs (111)B substrates. The superior uniformity and arbitrary placement of the nanopillars along with easy electrical contacting schemes make these ensembles extremely attractive for nanoscale electronic devices. In this study, the nanopillar growth is conducted under a variety of conditions including III/V rations, substrate temperatures and growth rates.  Nanopillars exhibit highly crystallographic hexagonal cross-section formed by (001) and (011) sidewalls. Pillar dimensions are ~200 nm in diameter and > 2 um in length. Micro-PL and electrical properties of these wires are also investigated.

Influences of Parents’ Health and Financial Support to Parents on Women’s Labor Market Withdrawal in Taiwan

發表人: 魏瀅珊 (夏威夷大學社會學系博士班)

 

http://www.asanet.org/ 

 

在台灣, 照顧父母仍然視為媳婦或女兒的責任. 文獻顯示,照顧父母所付出的勞力與時間可能降低婦女的參與勞動. 比較台灣婦女勞動參與率, 45-54歲以及55-64, 勞動參與率從60%降低到40%, 約有20%的婦女離開勞動力市場. 本文希望檢視照顧父母的工作是否會影響到婦女選擇離職或是減少工作時間. 此研究使用中研院家庭動態研究2001 2002兩年資料,追蹤3000,年紀在3564歲的受訪者. 研究發現, 只有在父母健康狀況不良的情形下, 婦女會有較高的離職比率或減少目前的工作時間. 如果父母的健康狀況良好, 婦女離職的比率較低, 對父母的照顧則是以給予較多的金錢支助替代實質的照顧工作.  

 

In Taiwan, taking care of elderly is considered to be the responsibility for daughter or daughter-in-law. Comparing Taiwanese women's labor force participation rates between age 45-54 and 55-64, it shows that the rates are 60% and 40% respectively, about 20% lower for the older cohort women. Previous research shows that elderly parents lead to a significant withdrawal from the labor force for female workers. In this paper, I focus on the relationship between elderly care in the household and female labor force participation in Taiwan. The data is from the "Panel Study of Family Dynamics," which was conducted by the Academic Sinica in Year 2001 and 2002. The sample size is 3000. My findings illustrate that only when elderly health is poor, women would significant reduce their working hours. Employed women are rather offering financial support to their parents, than leaving the labor force and giving the physical caring.