當今已有數以百萬計的行動應用程序在 Apple 的 App Store 中發布，並在iOS設備下載量超過150億次。為了保護iOS用戶免於惡意應用程式的傷害，Apple 對於上架之App 有相對嚴格的審查政策。通過審查的App才能在App Store中發布。在本文中，我們提出基於 iOS可執行檔的靜態字串分析技術用於檢驗App可能動態載入之類別 。為了檢查動態載入之類別是否符合Apple之規範，必須要能確定動態加載函數之可能字串參數值 。我們方法的第一步是使用現有工具擷取 iOS可執行檔的組合語言。然後自組合語言中建立整個程式的控制流程圖（CFGs） 。接著，在控制流程圖上識別動態加載類別的函數，並且對於該函數的每個參數，我們構造一個字串相依圖，用以顯示流向字串參數值的所有構成成分以及構成方式 。最後，我們對這些可能流向參數的字串進行字串分析，以確定這些參數值所有的可能值集合。透過把這些可能值與特徵值（從Apple 審查政策建構而來，例如私有/敏感性API），我們能夠檢測到App 潛在違背Apple政策之情形。我們分析了1300多種目前上架於App Store的App，並檢查他們是否違反蘋果關於使用私有API的政策以及 廣告識別碼（IDFA）政策。我們的工具提取了超過37000 這些App的字符相依圖，分析結果顯示208個App透過字串操作構組合出對應的API名稱並且有潛在的IDFA違規濫用之可能。我們的分析還發現了372個可以使用字串構建私有類名稱的應用程序和236個可以使用路徑字符串加載私有框架的App，這些App可能違反Apple 禁止使用私有API使用政策。 / Millions of mobile apps have been published in Apple's AppStore with more than 15 billion downloads by iOS devices. In order to protect iOS users from malicious apps, Apple has strict policies which are used to eliminate apps before they can be published in the AppStore. In this paper we present a string analysis technique for iOS executables for statically checking policies that are related to dynamically loaded classes. In order to check that an app conforms to such a policy, it is necessary to determine the possible string values for the class name parameters of the functions that dynamically load classes. The first step of our approach is to construct the assembly for iOS executables using existing tools. We then extract flow information from the assembly code and construct control flow graphs (CFGs) of functions. We identify functions that dynamically load classes, and for each parameter that corresponds to a dynamically loaded class, we construct a dependency graph that shows the set of values that flow to that parameter. Finally, we conduct string analysis on these dependency graphs to determine all potential string values that these parameters can take, which identifies the set of dynamically loaded classes. Taking the intersection of these values with patterns that characterize Apple's app policies (such as private/sensitive APIs), we are able to detect potential policy violations. We analyzed more than 1300 popular apps from Apple's AppStore and checked them against Apple's policy about the use of private APIs and the identifier for Advertising (IDFA). Our tool extracted more than 37000 string dependency graphs from these applications and our analysis reported 208 apps that compose the corresponding API with strings and have potential IDFA violations. Our analysis also found 372 apps that could have compose the private class name with string and 236 apps that could have load the private framework with path string; and could violate the private API usage policy.

In several mathematical models of physical or technical processes there are non-local boundary-value problems in terms of partial differential equations with integral conditions. In this article we consider hyperbolic differential equations of second order in the rectangle with some integral conditions and their relationship to boundary-value problems for some certain type of loaded equations. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Near field imaging using microwave in medical applications has gain much attention recently as various researches show its high ability and accuracy in illuminating object comparing to the well-known screening tools such as Magnetic Resonance Imaging (MRI), digital mammography, ultrasound etc. This has encourage and motivate scientists continue to exploit the potential of microwave imaging so that a better and more powerful sensing tools can be developed. This thesis documents the development of antenna design for microwave imaging application such as breast cancer detection. The application is similar to the concept of Ground Penetrating Radar (GPR) but operating at higher frequency band. In these systems a short pulse is transmitted from an antenna to the medium and the backscattered response is investigated for diagnose. In order to accommodate such a short pulse, a very wideband antenna with a minimal internal reflection is required. Printed monopole and planar metal plate antenna is implemented to achieve the necessary operating wide bandwidth. The development of new compact printed planar metal plate ultra wide bandwidth antenna is presented. A generalized parametric study is carried out using two well-known software packages to achieve optimum antenna performance. The Prototype antennas are tested and analysed experimentally, in which a reasonable agreement was achieved with the simulations. The antennas present an excellent relative wide bandwidth of 67% with acceptable range of power gain between 3.5 to 7 dBi. A new compact size air-dielectric microstrip patch-antenna designs proposed for breast cancer detection are presented. The antennas consist of a radiating patch mounted on two vertical plates, fed by coaxial cable. The antennas show a wide bandwidth that were verified by the simulations and also confirmed experimentally. The prototype antennas show excellent performance in terms the input impedance and radiation performance over the target range bandwidth from 4 GHz to 8 GHz. A mono-static model with a homogeneous dielectric box having similar properties to human tissue is used to study the interaction of the antenna with tissue. The numerical results in terms the matching required of new optimised antennas were promising. An experimental setup of sensor array for early-stage breast-cancer detection is developed. The arrangement of two elements separated by short distance that confined equivalent medium of breast tissues were modelled and implemented. The operation performances due to several orientations of the antennas locations were performed to determine the sensitivity limits with and without small size equivalent cancer cells model. In addition, a resistively loaded bow tie antenna, intended for applications in breast cancer detection, is adaptively modified through modelling and genetic optimisation is presented. The required wideband operating characteristic is achieved through manipulating the resistive loading of the antenna structure, the number of wires, and their angular separation within the equivalent wire assembly. The results show an acceptable impedance bandwidth of 100.75 %, with a VSWR < 2, over the interval from 3.3 GHz to 10.0 GHz. Feasibility studies were made on the antenna sensitivity for operation in a tissue equivalent dielectric medium. The simulated and measured results are all in close agreement.

Machine tools accuracy has been a cornerstone in defining machining system capability and directly affecting dimensional and geometrical tolerance of machined parts. The effort for achieving higher precision and accuracy can be distinguished in two general ideas. One is to improve performance of machine tools by designing better, stiffer and more accurate machine tools. The other is to develop tools and methods for evaluating and measuring their behaviour and gain knowledge of their performance. In order to properly control the machine tool characteristics that can affect and improve their accuracy such as static stiffness and static accuracy.This thesis is aiming at establishing and further advancing the idea of loaded testing of machining systems and the concept of Elastically Linked Systems as a framework for measuring, identifying and characterising quasi-static stiffness of machine tools under loaded conditions. This will allow the creation of an improved capability profile of machining system accuracy. The focus is on the implementation of Elastically Linked Systems concept (ELS) through the Loaded Double Bar system, a measurement method that can partly simulate the process-machine interaction by reproducing forces exerted on the machine tool structure for the evaluation of system characteristics under loaded condition. This allows the qualitative and quantitative evaluation and comparison of machine tools for the purpose of accuracy enhancement, identification of weak directions with potential utilization in process planning, machine procurement and maintenance.Through two case studies, the capability to identify the effect of machine components and structure behaviour is shown. / <p>QC 20180514</p>

This thesis provides a comprehensive investigation of flow-sound-structure coupling in spring-loaded valves subjected to air flow. While they are commonly used in a multitude of applications, these types of valves have been found to experience severe vibrations when interaction is present among the structure, the hydrodynamic field, and the acoustic field for a range of operational valve structural characteristics, flow parameters, and connected piping length. The first part of this investigation was aimed at characterizing experimentally the valve’s dynamic behaviour and the parameters affecting the onset of self-excited instability. The occurrence of instability was mainly driven by the presence of acoustic feedback: the connected length of piping had to be sufficiently long, with a longer pipe correlating to more severe vibrations. In addition, it was found that the valve’s oscillation frequency depends on the modal characteristics of the combined valve piping system, rather than the structural natural frequency alone. Furthermore, an increase in the valve’s spring stiffness caused the vibrations to become more severe. Meanwhile, other parameters such as initial spring preload force and valve plate area only had moderate effects on the stability behaviour of the valve. The second part of the investigation sought to develop a theoretical model that could simulate the valve’s response when subjected to air flow while considering the effects of acoustic feedback and impact on the seat and limiter. Thus, a structural model of the valve was developed based on a single-degree-of-freedom model of the system with impact computed based on a pseudo-force method. The hydrodynamic field relied on a one dimensional unsteady Bernoulli description of the flow. Finally, the acoustic interaction was accounted for using the one-dimensional wave equation resolved using a finite difference scheme. The model has demonstrated remarkable agreement with the experimental results. It has shown an ability to predict the modal characteristics of the system as well as correctly predict the effect of increased stiffness or increased piping length on vibration amplitude. The final part of the investigation consisted in designing countermeasures to mitigate the effects of this self-excited instability mechanism. A concentric Helmholtz-type cavity resonator, an orifice plate, and an anechoic termination are placed at the downstream side of a model valve which were seen to be unstable in the experimental and modelling phases of the investigation. All tested devices were able to eliminate the self excited instability mechanism. The applicability and robustness of each of these methods were discussed. / Thesis / Doctor of Philosophy (PhD)

No / A miniaturized conical helix antenna is presented, which displays vertical polarization with electrically small dimensions of 10mm×10mm×45mm. The resonance of the antenna is made tunable by adding a variable digital MEMS capacitor load at the bottom of the helix, giving a tuning range of 316 MHz to 400 MHz. The antenna demonstrates considerable impedance matching bandwidth and gain over the entire tuning frequency band. Most importantly, the antenna is capable of compact, flexible and easy integration into a wireless device package or for platform installation. / Datong of Seven Technology Group, for their support under the KTP project grant No. 008734.

Environmental stresses arising from temperature and moisture changes, and/or other aggressive fluid ingressions can degrade the mechanical properties of the adhesive, as well as the integrity of an adhesive interface with a substrate. Therefore such disruptions can significantly reduce the lifetime and durability of an adhesive joint.1-4 In this research, the durability of certain epoxy adhesive joints and coatings were characterized using a fracture mechanics approach and also by constant frequency impedance spectroscopy. The shaft-loaded blister test (SLBT) was utilized to measure the strain energy release rate (G) or adhesive fracture energy of a pressure sensitive adhesive tape. In this study, support for the value of the SLBT fracture mechanics approach was obtained. The SLBT was then used to investigate the effects of relative humidity on a model epoxy bonded to silicon oxide. Lastly, the effects of water and temperature on the adhesion of a commercial filled epoxy bonded to silicon oxide was characterized and interpreted. A novel impedance sensor for investigating adhesion was developed in a collaborative effort between Virginia Tech and Hewlett-Packard. Utilizing the technique of constant frequency impedance spectroscopy, the distribution and transport of fluids at the interface of adhesive joints was measured. A broad spectrum of adhesives was tested. In addition, the effects of hygroscopic cycling on the durability of adhesive coatings were measured for the commercial filled epoxy using the device. Lastly, recommended modifications of the experimental set-up with the new sensor are proposed to improve the technique. / Ph. D.

The field of biomedical sciences has been expanded through the introduction of a novel cohort of soft and intelligent microrobots that can be remotely operated and controlled through the use of external stimuli, such as ultrasound, magnetic fields, or electric fields, or internal stimuli, such as chemotaxis. The distinguishing factor of these microrobots lies in their propulsion system, which may encompass chemical, physical, or biohybrid mechanisms. Particularly, microrobots propelled by motile cells or microorganisms have found extensive usage because they combine the control/steerability and image-enhancement capabilities of the synthetic microstructures with the taxis and cell-interaction capabilities of the biological components. Spermatozoa (sperms), among other types of motile microorganisms and cells, are promising biological materials for building biohybrid microrobots because they are inherently designed to swim through complex fluids and organs, like those in the reproductive system, without triggering negative immune responses. Sperms are suitable for a variety of gynecological healthcare applications due to their drug encapsulating capability and high drug-carrying stability, in addition to their natural role of fertilization. One objective of this project is to help sperms reach the site of fertilization in vivo where the sperm count is low (20 million sperm per mL), a condition known as oligospermia. In order to reach this goal, we are developing alternative strategies for transporting a significant number of sperms, as well as improving the functionality of sperm-hybrid microcarriers. Here, we use a thermoresponsive hydrogel made of poly(N-isopropylacrylamide) (PNIPAM) and a non-stimuli-responsive polymer (IPS photoresist) to create four dimensional (4D)-printed sperm-hybrid microcarriers via two-photon polymerization (TPP). We present a multifunctional microcarrier that can: i) transport and deliver multiple motile sperms to increase the likelihood of fertilization, ii) capacitate/hyperactivate the sperms in situ through the local release of heparin, and iii) assist the degradation of the hyaluronic acid (HA), present in extracellular matrix (ECM) of oocyte-cumulus surrounded the Egg. HA degradation occurs through the local action of hyaluronidase-loaded polymersomes (HYAL-Psomes) that have been immobilized on the microcarrier's surface. Dual ultrasonic (US)/photoacoustic (PA) imaging technology can also be used to visualize a swarm of microcarriers, making them ideal candidates for upcoming in vivo applications. In addition, as a second objective, we demonstrate that similar sperm-hybrid microcarriers can be utilized to deliver targeted enzymes and medication for the treatment of gynecological cancer. As proof of concept, we show that combined therapy using enzymes and anti-cancer drugs is an appealing strategy for disrupting the tumor tissue microenvironment and inducing cell apoptosis, thereby offering a more effective cancer therapy. To achieve this, we functionalize the microcarriers with polymersomes loaded with enzymes (such as hyaluronidase and collagenase) and anti-cancer drugs (such as curcumin), respectively, and demonstrate their cargo-release capability, enzyme function, and therapeutic effect for targeting cervical cancer cells in vitro.:Abstract iv 1 Introduction 1 1.1 Motivation 1 1.2 Objectives 3 1.3 Structure of this dissertation 4 2 Background 5 2.1 Introduction on additive manufacturing technology 5 2.2 Direct laser writing (DLW) based on two-photon polymerization 6 2.2.1 Writing principles of two-photon lithography 8 2.2.2 Available materials for two-photon lithography 9 2.2.3 Engineering (Preprogrammed designs) 12 2.3 4D Lithography 13 2.3.1 Biodegradable microrobot 13 2.3.2 Stimuli-responsive micromotors 15 2.3.3 Other 4D-printing approaches 17 2.4 Motion at the microscale (Micromotility) 21 2.4.1 Physical propelled micromotors 23 2.4.2 Chemical propelled micromotors 32 2.4.3 Biohybrid micromotors 34 2.5 Other two-photon polymerized microrobots and their biomedical applications 35 2.5.1 Functionalized carriers 36 2.5.2 Multiple-cell carrying scaffolds 38 2.5.3 Single particle and cell transporters 39 2.6 Comparison of 3D and 4D-lithography with other fabrication methods 42 3 Materials and methods 44 3.1 Synthesis and fabrication 44 3.1.1 Synthesis of PNIPAM 44 3.1.2 Fabrication of microcarrier 44 3.1.3 Preparation of sperm medium and sperm solution 45 3.1.4 Preparation and composition of different body fluids 45 3.1.5 Fluidics channels 46 3.1.6 In situ preparation of microcarriers and sperms 46 3.1.7 Loading of microcarriers with heparin 46 3.1.8 Synthesis of block copolymers (BCPs) 47 3.1.9 Fabrication of Empty-Psomes A and D 48 3.1.10 Preparation of Curcumin complex CU(βCD)2 and calibration curve 49 3.1.11 Fabrication of cargo-loaded Psomes with enzymes and antitumoral drug 50 3.2 Characterization 51 3.2.1 MTS-Assay 51 3.2.2 Toluidine blue assay 52 3.2.3 Characterization of Empty-Psomes A and D: pH cycles and pH titration by dynamic light scattering (DLS) 53 3.2.4 Characterization of cargo-loaded Psomes with enzymes and antitumoral drug 54 3.2.5 Loading efficiency of HYAL-Psomes 55 3.2.6 Loading efficiency of MMPsomes 56 3.2.7 Loading efficiency, stability and release study of CU(βCD)2-Psomes 57 3.2.8 Size and polydispersity analysis of cargo-loaded Psomes in different simulated body fluids by DLS 58 3.2.9 Conformation and stability study of cargo-loaded Psomes in different simulated body fluids by asymmetric flow field flow fractionation (AF4) 59 3.2.10 Immobilization of the cargo-loaded Psomes on the surfaces 61 3.2.11 Enzymatic assay of HYAL for enzyme activity measurement 62 3.2.12 Enzymes assay in different simulated body fluids 64 3.2.13 Stability study of RhB-HYAL-Psomes in different pH 65 3.2.14 Calculation of the magnetic field flux of an external hand-held magnet 66 3.3 Temperature actuation and imaging 67 3.3.1 Temperature actuation test of PNIPAM and video recording 67 3.3.2 Hybrid ultrasound (US) and photoacoustic (PA) Imaging 67 3.4 Other useful information 68 3.4.1 pH and temperature through the female reproductive tract 68 3.4.2 Calculation of the light-to-heat conversion during imaging process 69 4 Multifunctional 4D-printed sperm-hybrid microcarriers for assisted reproduction 72 4.1 Background 72 4.2 Concept and fabrication of the 4D-printed microcarriers 74 4.3 Sperm coupling and geometrical optimization of microcarrier 77 4.4 Characterization of the 4D-printed streamlined microcarriers 78 4.5 Microcarrier loaded with heparin for in situ sperm capacitation 82 4.6 Microcarriers decorated with HYAL-Psomes for in situ degradation of the HA-cumulus complex 86 4.6.1 Immobilization of HYAL-Psomes on the microcarrier’s surface 89 4.6.2 Qualitative study of cumulus cell removal 90 4.7 Sperm-microcarrier motion performance in oviduct-mimicking fluids 91 4.7.1 Capture, transport, and release of sperms 92 4.7.2 Sperm-microcarrier motion performance on ex vivo oviduct tissue 93 4.8 Tracking of a swarm of microcarriers with a dual ultrasound (US) and photoacoustic (PA) imaging system 95 4.9 Summary 96 5 Polymersomes-decorated micromotors with multiple cargos for gynecological cancer therapy 98 5.1 Background 98 5.2 Characterization and size quantification of Psomes before and after loading of cargoes by DLS, and Cryo-TEM 103 5.3 Characterization and size quantification of cargo-loaded Psomes by DLS, and Cryo-TEM in different simulated bodily fluids 104 5.4 Immobilization and characterization of cargo-loaded Psomes on the microcarrier’s surface 106 5.5 Immobilization and characterization of dual cargo-loaded Psomes on the microcarrier’s surface 108 5.6 Investigation of ECM degradation and antitumoral effect of cargo-loaded Psomes 110 5.7 Magnetic and bio-hybrid guidance of microcarriers toward targeted cargo delivery 115 5.8 Summary 117 6 Conclusion and Outlook 119 6.1 Achievements 119 6.2 Outlook 121 Bibliography I List of Figures and Tables XXI Acknowledgements and funding XXIV Scientific publications and contributions XXVI Curriculum Vitae XXVII

No / A novel multi-standard dual-wide band filter with a compact size of only 8.8 mm by 16.8mm is designed and developed for transceiver devices. The proposed filter has a fundamental bandwidth of 1.6GHz with fractional bandwidth (FBW) of 29.7% centered at the 5.4GHz band, and second bandwidth of 300.0MHz with FBW of 3.6% centered at the 8.15GHz band. The basic dual-wide bandwidth is attributed to the interaction of the novel modified polygon pair and upper stub loaded stepped impedance resonator. Moreover, the added down stub loaded stepped impedance resonator (SLSIR) further enhances the pass band performance by widening the bandwidth and optimizing reflection coefficient performance considerably. To validate the proposed ideas, the multi-standard filter is designed and simulated by Ansoft HFSS software. The simulated results agree well with the theory predictions. The featured broad bandwidths over two frequency bands and the miniaturized size of the proposed filter make it very promising for applications in future multi-standard wireless communication.

A series of static lateral load tests were conducted on a group of fifteen piles arranged in a 3x5 pattern. The piles were placed at a center-to-center spacing of 3.92 pile diameters. A single isolated pile was also tested for comparison to the group response. The subsurface profile consisted of cohesive layers of soft to medium consistency underlain by interbedded layers of sands and fine-grained soils. The piles were instrumented to measure pile-head deflection, rotation, and load, as well as strain versus pile depth.