1,721,014 research outputs found
Characterization and regularity for axisymmetric solenoidal vector fields with application to Navier-Stokes equation
Get PDF1 online resource (PDF, 34 pages)Liu, Jian-Guo; Wang, Wei-Cheng. (2008). Characterization and regularity for axisymmetric solenoidal vector fields with application to Navier-Stokes equation. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/179967
An opt-in framework for privacy protection in audio-based applications
Get PDFInstalling audio-based applications exposes users to the risk of the data processor extracting additional information beyond the task the user permitted. To solve these privacy concerns, we propose to integrate an on-edge data obfuscation between the audio sensor and the recognition algorithm. We introduce a novel privacy loss metric and use adversarial learning to train an obfuscator. Contrary to existing work, our technique does not require users to specify which sensitive attributes they want to protect (opt-out) but instead only provide permission for specific tasks (opt-in). Moreover, we do not require retraining of recognition algorithms, making the obfuscated data compatible with existing methods. We experimentally validate our approach on four voice datasets and show that we can protect several attributes of the speaker, including gender, identity, and emotional state with a minimal recognition accuracy degradation
Numerical Schemes for Three Dimensional Irregular Shape Quantum Dots over Curvilinear Coordinate Systems
No full textPrivacy-preserving visual analysis : training video obfuscation models without sensitive labels
Get PDFVisual analysis tasks, including crowd management, often require resource-intensive machine learning models, posing challenges for deployment on edge hardware. Consequently, cloud computing emerges as a prevalent solution. To address privacy concerns associated with offloading video data to remote cloud platforms, we present a novel approach using adversarial training to develop a lightweight obfuscator neural network. Our method focuses on pedestrian detection as an example of visual analysis, allowing the transformation of video frames on the camera itself to retain only essential information for pedestrian detection while preserving privacy. Importantly, the obfuscated data remains compatible with publicly available object detectors, requiring no modifications or significant loss in accuracy. Additionally, our technique overcomes the common limitation of relying on labeled sensitive attributes for privacy preservation. By demonstrating the inability of pedestrian attribute recognition models to detect attributes in obfuscated videos, we validate the efficacy of our privacy protection method. Our results suggest that this scalable approach holds promise for enabling camera usage in video analytics while upholding personal privacy
Studies on the Mechanism of SUMOylation between HIF-1α and PIAS2 under Hypoxia in HepG2 Cells
No full text肝癌在許多先進國家是癌症死亡的主要原因，而一直以來也高居台灣十大癌症死因首位，對國人健康影響甚鉅。肝癌的發展過程常常伴隨著缺氧狀態的產生，且肝癌是多血管型的腫瘤，缺氧狀態下其缺氧誘導因子-1α(HIF-1α)所主導的血管新生會促進肝癌腫瘤的發育。此外，臨床證據顯示肝癌病人組織SUMO-1的表現較正常組織為高，顯示SUMO化在肝癌癌化過程中扮演了一定的角色。缺氧誘導因子-1α，為一種對於氧分壓敏感的轉錄因子，在正常氧分壓下很快就會被降解，在缺氧狀態下的轉錄活性與穏定度受到多種轉譯後修飾(posttranslational modifications)所調控，其中包括SUMO化。SUMO化能改變細胞中分子的行為，諸如轉錄因子的活化或抑制、影響細胞中分子的穏定度、改變分子在細胞膜上的位置。而目前已知HIF-1α在缺氧狀態下會被SUMO化修飾，且SUMO化的循環中有E1活化酶(AOS1/UBA2)、E2銜接酶(UBC9)及SENP-1去SUMO酵素的參與，且SENP-1為HIF-1α下游基因，與HIF-1α之間存在著正迴饋的關係，但目前仍不清楚為何種SUMO E3黏合酶參與其中。近年來許多研究指出SUMO E3黏合酶－PIAS家族成員和腫瘤惡化與血管新生的相關性，其中PIAS2，又名PIASx(Protein Inhibitors of Activated STAT 2;PIAS2;PIASx)為PIAS SUMO E3連結酶家族成員之一，在正常肝臟組織中會高度表現，故本研究希望能夠透過進一步實驗，觀察當肝癌細胞處於缺氧微環境時，PIAS2是否參與在HIF-1α SUMO化過程中，以了解PIAS2在缺氧狀態下肝癌發育中所扮演的角色。本研究採用肝癌細胞株HepG2及HEK293T做為材料，以西方墨點法分析，利用缺氧系統培養箱或氯化亞鈷(II)所引起的缺氧狀態處理HepG2，發現其PIAS2的蛋白表現量並沒有改變；利用pcDNA3.1 -HA-HIF-1α對HEK293T進行暫時性轉染(transient transfection)，發現HIF1-α大量表現後並不會去影響PIAS2蛋白表現量；而利用免疫沈澱法觀察到細胞在缺氧狀態下不改變HepG2中PIAS2及SUMO-1蛋白表現量，且SENP-1被誘發的條件下，會促進PIAS2與HIF-1α之間的交互作用，也會增進HIF-1α與SUMO-1之間的交互作用；以PIAS2 shRNA慢病毒載體將HepG2的PIAS2進行靜默，觀察到缺氧狀態下PIAS2靜默HepG2和正常細胞相比，其HIF-1α與SUMO-1之間的交互作用程度會降低，且HIF-1α的穏定度也會下降，而在核質分離的結果中也發現，HIF-1α及SENP-1在核內的分布會減少。另外，在HRE promoter reporter assay方面，發現缺氧狀態下，在內生性PIAS2表現量靜默後，缺氧反應元件(hypoxia responsive element, HRE)活性會明顯地下降，此外利用RT-PCR也觀察到HepG2中HIF-1α下游基因VEGF及Glut-1，其mRNA表現量也有明顯減少的現象。總結以上結果，在缺氧狀態下HepG2中的PIAS2可藉由與HIF-1α交互作用並對其SUMO化，增加穏定度進而使HIF-1α進入核內。進核後SUMO型態的HIF-1α，會被SENP-1去SUMO化，而趨於穏定與HIF-1β結合至缺氧反應元件(hypoxia-resposive element, HRE)，使HRE活性上升，並轉錄活化下游基因VEGF及Glut-1之表現。本研究證明PIAS2於缺氧狀態訊息傳遞與下游反應的功能性重要角色。然而，其中可能牽涉其他SUMO E3黏合酶與轉譯後修飾作用參與則需要更進一步的實驗來探討相關機制。Hepatocellular carcinoma(HCC), which posed dangerous threat to human health, was the leading cause of death among cancers worldwide, including Taiwan. The development of HCC was always along with hypoxic conditions. Moreover, HCC was a hypervascular tumor and hypoxia-inducible factor-1α(HIF-1α)-mediated angiogenesis under hypoxia played an important role in its progression. Additionally, clinical studies have shown that the expression level of SUMO-1 was more higher in HCC tissue than non-neoplastic tissue, which suggested that SUMOylation plays a key role in the development of HCC. HIF-1α was a transcription factor that was rapidly degraded during normoxia and its ability to transactivate downstream genes and stability of HIF-1α was tightly regulated by many posttranslational modifications under hypoxia, including SUMOylation. SUMOylation could regulate diverse cellular functions, including transcription, nuclear translocation, and stress response. Previous studies have shown HIF-1α was modified by SUMO-1 under hypoxic conditions. In the process of HIF-1α SUMOylation, E1-AOS1/UBA2, E2-UBC9 and SENP-1 were involved. SENP-1, which was also a target gene of HIF-1α, could regulate HIF-1α by positive feedback under hypoxia. Nevertheless, how HIF-1α became SUMOylated by which SUMO E3 ligases during hypoxia is still unknown. According to recent research, there was emerging evidence showing that several members of PIAS(Protein Inhibitors of Activated STAT) SUMO E3 ligase family were possibly correlated to tumorogenesis and angiogenesis. PIAS2, a member of PIAS protein family, was highly expressed in liver. The aim of this study was to investigate the correlation of SUMOylation between HIF-1α and PIAS2 in human hepatocarcinoma cell line(HepG2). Treatment of 0.5% oxygen in hypoxia chamber and CoCl2 could not alter the protein level of PIAS2 in HepG2 cells. Molecular approaches to overexpress HIF-1α protein expression in HEK293T cells did not affect the protein level of PIAS2. Additionally, hypoxic conditions could enhance not only the interaction between PIAS2 and HIF-1α but also SUMO-1 and HIF-1α by Immunopreciptation(IP) in HepG2 cells on condition that SENP-1 could be induced. Besides, we used PIAS2 shRNA to silence the endogenous PIAS2 expression in HepG2 cells, and we subsequently found that the interaction between SUMO-1 and HIF-1α, the nuclear translocation of HIF-1α and SENP-1 and HRE activity were significantly reduced in PIAS2 silenced HepG2 cells compared to wild type cells under hypoxia. Furthermore, mRNA level of hypoxia-responsive genes such as VEGF and Glut-1 were significantly decreased in PIAS2 silenced HepG2 cells under hypoxia. Overall, we concluded that PIAS2 could play a key role in the process of HIF-1α nuclear translocation and transactivation activity via SUMOylating HIF-1α under hypoxic conditions. This study demonstrated that PIAS2 may play a key role in the hypoxia-mediated signaling and downstream gene expression. However, we will further confirm if there is any other SUMO E3 ligase and posttranslational modification involved in the mechanism of HIF-1α SUMOylation under hypoxia
A 2-V 7.2?a Jitter AM-Suppression CMOS Amplifier using Current-Mode Hybrid Magnitude Control
No full textAn Exploratory Study on the Business Model and Strategy of Solar Facade
No full text利用太陽光發電具有取之不竭，用之不盡及較不受地理環境限制的優點，對於天然資源缺乏的國家，太陽光電再生能源產業發展，不但可以達到節能減碳的效益，更提高本國能源自主性。 但是太陽能帷幕牆因太陽能光電板電池模組之成本高、發電功能及滿足建築物功能等限制，而面臨普及化之發展瓶頸。各國政府及產學界除持續在太陽能光電板電池模組科技研發及相關服務模式進行創新與整合外，由於太陽能帷幕牆價值網絡相當複雜，其商業模式的創新也將決定太陽能帷幕牆能否加速發展的關鍵因素。本研究認為商業模式的創新有必要從產業現況及發展趨勢的觀點切入，進一步審視限制太陽能帷幕牆的因素，據以辨識現在帷幕牆市場與區隔中適合太陽能帷幕牆先行導入的利基市場，並分析滿足利基市場內目標顧客價值主張之主要限制因素，以規劃具發展可行性的整合服務商營運模式。 本研究採用破壞式創新理論及商業模式設計流程，以顧客待完成的工作概念進行市場區隔分析，並選定商業建築或辦公大樓為太陽能帷幕牆先行切入之利基市場，並提出具價值創新之商業模式；另外，為避免忽略傳統帷幕牆市場實際運作情勢可能產生的問題，因此本研究運用價值網絡及企業生態系統等理論，深入分析限制利基市目標顧客採用太陽能帷幕牆的因素，及整合服務商所需建構之競爭資源，以確認本研究所提出之商業模式及關鍵資源發展策略等論述之合理性及可行性。 經此分析與推導，本研提出成立「電能供應管理整合服務商」之中介者概念，以提供商業建築或辦公大樓完整性、簡單性、便利性，及較低總持有成本的全生命週期電能供應管理整合服務方案，依用電量為計價單位(Pay-By-kWh)之創新供電管理整合服務商業模式，並提出滿足樞紐企業核心策略原則之智慧型儲供電管理系統設計之建議。The use of solar power is inexhaustible and more from the advantage of geographical constrains. For the country which lacks natual resources, photovoltaic industry is not only provides benefits of energy saving and carbon reducing, but also improves the country’s energy autonomy. However, due to unaffordable photovoltaic cost, limited power generation function and satisfy of building function. In addition to continuous efforts from government industries and academies for solar module in the area of technology, performance improvement and services innovation, it is believed that, innovative busiess model for solar façade plays an essential role to assure successful development. This thesis study aims at developing a feasible and innovative business model for an integrated service provider in the solar façade industry by reiterating current market situation as well as its possible future development by an indepth investigation on potential constraints against the industry development. Applying insights from disruptive innovation and business model design introduced by Clayton Christensen and Mark Johnson respectively, we therefore indentify that commercial or office building is the most suitable market segment to adopt solar façade. Furthmore a businsess model with value creation to target customer is developed. This study also applies concepts both of Value Network and Business Ecosystem for further assement over possible constrains that might defer the adoption for solar façade purchase and proposes an integrated service provider to develop required resources to cope with competition. By doing so. business model and key resource development strategy proposed by this study can prove to be more reasonable and feasible. Finally, this study proposes an innovative business model that includes introduction of concept of “Power Supply and Management Integrated” as an intermediary and a total solution to provide commercial or office building operators with stable and reliable life through integrated power supply and management services in the way of integrity, simple, convenient and lower total cost of ownership. The proposed business model could be profitable of power usage (Pay-By-kWh) as main revenue stream. In addition, this study also recommends the integrated service provider develop a Intelligently Power Supply Management System in order to successfully execute a keystone strategy for competition
Dynamic Software Updating in Wireless Sensor Networks
No full text無線感測網路是由許多便宜、微小、自治的裝置組成，他們常用於監測環境況狀，並彼此交換通訊資訊。在將他們佈建之後，仍有可能需要更新上面的程式，例如為了修正程式錯誤、需求修改，或是其他的維護。因為在無線感測網路下軟硬體或環境較為受限，在無線感測網路上的軟體更新成為一項挑戰與議題。
在先前的研究，軟體更新後往往需要將裝置重新啟動。然而，重新啟動的成本所費不貲，因為裝置運行所有蒐集與建立的珍貴資料都會遺失。例如需要時間重新與其他裝置同步，或是需要額外的網路頻寬來重新路由表。
這篇提出了uFlow，他是一個程式範式和他的簡單的原型實作。uFlow可以讓程式在更新後，直接套用新的程式，而不需要重新啟動裝置，因此得以保留資料。uFlow執行時，大約會有88時脈週期的額外負擔，只發生在工作切換時。而原型引擎大約需要420位元組用於執行迴圈與核心功能，而TinyOS-1.x的執行核心則大約需要400位元組。A wireless sensor network consists a number of small, cheap and autonomous devices communicating with each other for monitoring environment conditions. After the deployment, there is still a need for updating the software in the nodes due to bug fixes, requirement changes, or other maintenance reasons. Software updating in wireless sensor networks has became a challenge because of the constrained hardware resources and environment.
In previous works, the node is required to reboot after software update. However, reboot is costly since the previous runtime status is lost. It needs time and bandwidth to synchronize with other nodes or rebuild routing table.
The thesis presents uFlow, a programming paradigm and a prototype implementation for wireless sensor networks. uFlow allows application to update without rebooting the node therefore preserving precious runtime states. The execution overhead is around 88 clock cycles, which is slightly larger than TinOS, but fortunately the overhead only occurs when task transitions. The prototype implementation is about 420 bytes for task loop and core helper APIs and 146 bytes for helper APIs used to facilitate the dynamic update, while TinyOS-1.x costs around 400bytes
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