Adaptation of Microwave-Induced Thermoacoustic Imaging to Subcutaneous Vasculature: Toward an All-Electronic, Embeddable Imaging Platform for Biometric Applications

Seyed Aliroteh, Seyed Miaad ProQuest Dissertations & Theses Stanford Universit 2021 해외박사(DDOD)

Imaging of subcutaneous vasculature is of great interest for biometric security and point-of-care medicine. In this thesis, I investigated the feasibility of microwaveinduced thermoacoustic tomography as a safe, compact, low-power, and cost-effective imaging technique for subcutaneous vasculature by means of application-specific customization. I began with a focus on order-of-magnitude improvements in the required microwave-domain excitation power and ultimately demonstrated the first miniturizable adaptation of thermoacoustic (TA) imaging specifically designed to detect shallow penetration-depth, subcutaneous vasculature. The key contribution was introducing a new concept and design methodology of near-field RF applicators, which resulted in proof-of-concept TA imaging of synthetic phantoms, plant vasculature, and earthworm blood vessels with only 50 W of peak power, or 42 mW average power, at 300 µm resolution. The proposed RF applicator design enabled uniform, orientationindependent illumination of vasculature phantoms with only 10% variation. I continued with customization in the ultrasound-domain, where I introduced a new concept of spatial difference imaging (SDI) implemented on silicon as an 8-channel TA analog front-end (AFE) designed on Texas Instrument Inc.’s proprietary 180 µm BCD process. The AFE simultaneously achieves less than 0.75 pA/√ Hz effective current noise and less than 0.64 nV/√ Hz effective voltage noise over a target bandwidth of 15 MHz when loaded with up to 10 pF of sensor capacitance. Additionally, the AFE is capable of maintaining an input CMRR greater than 60 dB with a minimum SFDR of 50 dBc that achieves the desired output linearity over the target bandwidth while handling up to 50 pF loading per channel, which is critical for SDI-based TA imaging in the intended application known to require at least 40 dB of imaging dynamic range.This new SDI concept not only required an application-specific circuit design approach in hardware, but innovations in post-processing for image-reconstruction on the software side as well. In particular, I established a theoretical framework to formalize an understanding of SDI, which resulted in an image-reconstruction algorithm that elegantly splits into a one-time, computation-heavy algorithm intended for a traditional computer or server and a light computation that can run on a mobile device or microprocessor during scan-time. Proof-of-concept measurements show that SDI alleviates dynamic-range (DR) requirements by 22 dB, boosting vascular signatures by +40% to +80% while rejecting skin signatures by -20%, and addresses the remaining challenge of low-SNR TA imaging. I further demonstrate that, with a fully SDI-customized AFE, high quality imaging is possible with only 40 dB of DR, without the need of any time-gain control, all with greatly reduced digitization complexity of only 8-bits. Finally, all the proposed customization leading to a miniature, high-resolution, highcontrast, low-power yet highly-sensitive TA imager will inevitably have to also deal with the reality of interference in a practical manner. To address this, I outline interference mitigation strategies, such as multi-physics-optimized construction material selection and active microwave-to-ultrasound leakage cancellation techniques, needed to transform my proof-of-concept prototypes into a more user-friendly final product.

Essays on Environmental and Labor Economics

Khosroshahi, Seyed Amirreza Seyed Northwestern University 2016 해외박사(DDOD)

This dissertations consists of three chapters. The first chapter is on the topic of environmental economics and studies the question of the effects of air pollution on students' school absences, finding significant and positive effects for air pollution, and PM10 in particular, on school absences. The second chapter is on the topic of labor economics and considers the determinants of international migration, with a focus on wage differences as the main explanatory variable. The analysis finds a positive and significant effect for wage differences across countries on the proportion of emigrants to non-emigrants from the source country. Finally, the last chapter analyzes the effects of issuance of cotton dust standards in the US on the productivity of textile industry and finds weak and negative effects for those regulations.

Molecular Manipulation of the Chloroplast Genome in Nicotiana Species for Overexpression of Heterologous Proteins

Seyed Javad Davarpanah Shahri 忠南大學校 大學院 2009 국내박사

Dynamic simulation of tuna purse seine gear verified by field experiments

Seyed Abbas Hosseini 부경대학교 2011 국내박사

Abstract The purse seine gear consists mainly of flexible components; nettings, ropes and purse line, which are considered a flexible structure. To describe the dynamic behaviour by the numerical method, mass-spring model, as the mechanics of flexible twine, was applied to the system including three main components: netting, purse line and purse seiner. The equations of motion of the mass points were adapted and integrated by the fourth-order Runge-Kutta method to qualify the displacements of the mass points for the net shape in 3-D under the flow condition. The present study removes the inadequacies of the last paper on mackerel purse seine by refining the calculation model to consider drag coefficient as a function of attack angle and Reynolds number applicable to the setting operation of the purse seine gear. An estimate of the validity of the numerical simulation is made by comparing the measured and calculated values for the sinking depth of the net. Discussions are made on the some adequacies of the modeling method along with suggestions for any improvement. The numerical simulation was used to examine the sinking performance of the different designs in which large meshed-panels and netting materials are used together in the main body section of the netting. The results indicate that the nets with larger mesh panels take more sinking depth with much more pronounced operational depth at corresponding times of the fishing operation when heavier netting material is used as compared to the prototype net. Moreover, with the new designs, lower tensile forces were exerted on both ends of the pure wire during pursing. A preliminary analysis was made on the swimming behavior of skipjack school in responses to the purse seine operation. The new constructions of the nets with regard to the operational depth represent alternatives that may reduce the potential problem of frequent failed setting of the tuna purse seine gear. 다랑어 선망 어구의 역학적 거동 시뮬레이션과 해상실험에 관한 연구 Seyed Abbas Hosseini 부경대학교 대학원 수산물리학과 요약 선망어구는 주로 망지, 로프, 조임줄과 같은 유연 구조체로 구성된다. 수치해석을 적용함으로써 어구의 역학적 거동을 해석하기 위하여 질량-스프링 모델을 적용하였고, 망지, 조임줄, 선망 어선을 주된 구성요소로 고려하였다. 조류의 영향에 대한 그물 형상의 질점 변위를 3차원으로 구현하고 검증하기 위하여 질점의 운동 방정식과 4차 Runge-Kutta법을 적용하였다. 다랑어 선망어구에 초점을 둔 본 연구는 레이놀즈수와 영각의 함수로 표현되는 항력계수를 고려한 수치모델을 개선함으로써 고등어 선망에 관한 이전 연구의 부적절성을 제거하였다. 수치 시뮬레이션을 검증하기 위해 그물의 침강수심에 대한 측정값과 계산값을 비교하였다. 고찰에서는 개선된 모델링 방법의 타당성을 다루었다. 기존의 몸그물에 대형 망목으로 이루어진 판넬과 다른 재질의 망지를 사용하여 다른 조건에 대한 그물의 침강 성능을 시뮬레이션하였다. 본 연구 결과, 몸그물 부분에 대형 망목을 사용한 그물에 대하여, 어획시간에 대한 그물의 침강 수심은 기존 재질을 사용한 그물에 비해 비중이 큰 재질의 망지를 사용한 그물에서 더 크게 나타났다. 또한, pursing이 이루어지는 동안 조임줄의 양 끝단에 더 낮은 장력이 작용하였다. 연구에 앞서, 선망 조업 작업에 대한 가다랑어군의 유영행동 관련 연구가 개략적으로 수행되었다. 적용 수심과 제작 비용에 관한 그물의 새로운 구조개선은 다랑어 선망 어구의 높은 실패율 등 잠재적인 문제를 감소시키기 위한 대안이 될 수 있다.

1D-2D nanomaterials for electronic and optoelectronic applications

Hosseini Shokouh, Seyed Hossein Graduate School, Yonsei University 2015 국내박사

The electronics industry has revolutionized almost every area of society from household application to communication and medical sector. Keeping exponential growth in progress and fabricating small and highly efficient devices following the Moore’s law has lead researchers to pursue research on nanoscale materials and devices for smaller size and more possible functionalities and performance enhancement. In the beginning of 21st century a lot of nanomaterials and their synthesis methods have been developed thus enabling researchers to develop 0D, 1D, 2D and 3D nanomaterials. These nanomaterials have also been used to demonstrate electronics circuits, sensors etc. and have shown great potential for future devices. Here in this research work prospective of ZnO NW along with MoS2 and WSe2 NFs, as 1D-2D nanomaterials, were explored for their application in electronics and optoelectronics circuit application. On a single ZnO nanowire (NW), an inverter-type device was fabricated comprised of two back-to back Schottky diodes (SD) but one of these diodes was transformed to top gate-controlled FET by atomic layer deposited (ALD) Al2O3 with transparent conductive gate. As a result, this non-classical device configuration could simply operate as an inverter with Schottky-barrier (SB) FET and SD respectively as driver and load; so that, voltage signals could be well extracted as output. In addition, NW FET with a transparent conducting oxide as top gate turned out to be very photo-sensitive although ZnO NW SD was blind to visible lights. Based on this, we could achieve an array of photo-sensing inverter (photo-inverter) on one NW. To fabricate more efficient nanoelectroinc devises we integrated different nanoscale building blocks, so-called hybrid approach, for practical device applications. We demonstrated a hybrid inverter-type nanodevice comprised of MoS2 nanoflake field-effect transistor (FET) and ZnO nanowire Schottky diode on one substrate with multifunctional capacities of low power consumption, high gain, and photo-detection. We used nanotransfer printing method using polydimethylsiloxane for the fabrication of patterned bottom-gate MoS2 nanoflake FETs, so that they could be placed near ZnO nanowire Schottky diodes which were initially fabricated. The ZnO nanowire Schottky diode and MoS2 FET worked respectively as load and driver for a logic inverter, which exhibits a high voltage gain of ~50 at supply voltage of 5V and also shows a low power consumption of less than 50 nW. Moreover, inverter effectively operates as a photo-inverter detecting visible photons, since MoS2 FETs appear very photo-sensitive while the serially-connected ZnO nanowire Schottky diode was blind to visible lights. In next step to peruse the hybrid approach and fabricate even more efficient nanoelectroinc devises, we introduce a 1 dimensional-2 dimensional (1D-2D) hybrid complementary (h-CMOS) logic inverter by coupling p-channel WSe2 nanosheet FET and n-channel ZnO nanowire FET on a glass substrate aiming at high speed, low power consumption devices. In order to place WSe2 nanosheet near ZnO nanowire FET, we used a direct imprinting method as we used for ZnO NW and MoS2 NF photo-inverter. Considering the power consumption, we used one ohmic and one Schottky contact for the source and drain (or vice versa) of ZnO nanowire FET which would be connected in series to a bottom gate WSe2 nanosheet FET. Our nanowire-nanosheet h-CMOS inverter demonstrated a maximum voltage gain over 60, maximum power consumption of subnano-to-a few nW, and at least 1 kHz switching speed on glass. Although the hybrid approach resulted in nanoelectronic devises with amazing property, it is suffering from poor performance of 2D WSe2 FET. Therefore as final step, we tried to optimize and fabricate high performance air-stable p-channel WSe2 top-gate field effect transistors (FETs) using a bilayer gate dielectric composed of high- and low-k dielectrics. Since using the high-k Al2O3 alone as top-gate dielectric degrades the electrical property of p-channel WSe2, we deposited thin fluoropolymer (CYTOP) as buffer layer to protect the 2 dimensional (2D) channel from high-k oxide forming process. As a result, we properly realize a top-gate-patterned 2D WSe2 FET. Our top-gate p-channel WSe2 FET demonstrates a high hole mobility of 100 cm2/V.s and ION/IOFF > 107 at low gate voltages (VGS ~ -4 V) and a drain voltage (VDS) of -1 V on glass substrate. Furthermore, the top-gate FET shows very good stability in air ambient with a relative humidity of 45% for 7 days since device fabrication.

Grammatical relational database model

Seyed-Abbassi, Behrooz Kavkani University Microfilms International 1987 국내박사

Energy and Laplacian energy of graphs

SEYED AHMAD MOJALLAL 성균관대학교 일반대학원 2016 국내박사

In this thesis we study: • Basic definitions with a list of some previously known results. • Some lower and upper bounds on energy and Laplacian energy of graph G. • Nordhaus-Gaddum-type results on Laplacian energy of graphs. • Characterization of extremal bipartite graphs for graph energy. • An upper bound on Laplacian energy of bipartite graphs. • A relation between the energy of line graph E(LG) and the signless Laplacian energy LE+(G) of graph G. • Comparison between the energy of line graph E(LG) and the energy E(G) of graph G. • Upper and lower bounds on E(LG) with characterization of extremal graphs. • Some results pertaining to equienergetic and hyperenergetic graphs. • The threshold graphs with the first four minimal Laplacian energies. • The threshold graphs with the largest and the second largest Laplacian energies. • A relation between energy E(G) and Laplacian energy LE(G) of graph G. • A relation between energy E(G), Laplacian energy LE(G) and signless Laplacian energy LE+(G) of graph G. • A relation between Laplacian energy LE(G) and Laplacian–energy–like invariant LEL(G) of graph G.

Robustly shadowable sets and hyperbolicity

Seyed mohammad reza Bagherzad sessary 충남대학교 대학원 2016 국내박사

(A) maturity assessment model for urban smart factory as an emerging manufacturing paradigm

Sajadieh, Seyed Mohammad Mehdi Sungkyunkwan University 2022 국내박사

Global trends such as individualization, climate change, emissions, energy and resource scarcity, and urbanization have transformative impacts on the manufacturing sector. Although manufacturing efficiency and productivity can be improved through traditional operations research and technology-driven advancement like smart manufacturing, it is not enough to settle the aforementioned megatrends. Numerous benefits are cited as urban production studies become more prevalent, including shorter lead times, minimizing costs, and increasing the degree of personalization by engaging customers in the design process, as well as reducing transportation emissions and integrating work and home. Considering its benefits, urban production could be a solution to these megatrends. However, logistical problems, environmental issues, and spatial challenges also need to be addressed. This study proposed the concept of the Urban smart factory, as implementing principles and key technologies of smart factory to achieve human-centricity, sustainability, and resilience in urban production at the highest level. This study went beyond simply supplying a conceptual definition of the urban smart factory. In addition to the concept, the urban smart factory was outlined in terms of its structure, key technologies, and detailed attributes. Based on a review of the smart factory and Industry 4.0 maturity models, it was revealed that the urban smart factory assessment could not be performed by using these models. This study developed a maturity assessment model based on the proposed urban smart factory for evaluation of the urban factories. To evaluate the effectiveness and appropriateness of the developed Maturity Assessment Model for the urban smart factory, an assessment has been done for two case studies from different sectors. 개별화, 기후 변화, 에너지 및 자원 부족, 도시화와 같은 글로벌 추세는 제조 부문에 혁신적인 영향을 미친다. 전통적인 운영연구와 기술 주도의 발전을 통한 스마트제조에 의해 제조 효율성과 생산성이 향상될 수 있지만, 앞서 언급한 메가트렌드를 정착시키기에는 역부족이다. 도시 생산 연구가 더 널리 보급됨에 따라 리드 타임 단축, 비용 최소화, 디자인 프로세스에 고객 참여를 통한 개인화, 운송 배출 감소 등 많은 이점이 있다. 이점 고려할 때 도시 생산은 이러한 메가트렌드에 대한 솔루션이 될 수 있다. 그러나 물류 문제, 환경 문제 및 공간 문제도 해결해야 한다. 본 연구에서는 도시 생산에서성, 인간중심, 지속가능성, 회복력성을 최고 수준에서 달성하기 위한 스마트팩토리의 구현 원리와 핵심 기술로서 도시형 스마트팩토리의 개념을 제안하였다. 본 연구는 단순히 도시형 스마트팩토리에 대한 개념적 정의를 제공하는 데 그치지 않았다. 개념과 더불어 도시형 스마트팩토리을 구조, 핵심 기술, 세부속성 측면에서 개략적으로 설명했다. 스마트팩토리와 인더스트리 4.0 성숙도 모델을 검토한 결과, 이러한 모델을 사용하여 도시형 스마트팩토리 평가를 수행할 수 없는 것으로 확인되었다. 본 연구에서는 제안된 도시형 스마트공장 모델 기반으로 도시공장 평가를 위한 성숙도 평가 모델을 개발하였다. 도시형 스마트팩토리에 대한 개발된 성숙도 평가 모델의 효과성과 적절성을 평가하기 위해 서로 다른 부문의 두 가지 사례 연구에 대한 평가가 수행되었다.

Modeling and experimental vertificational of sheet metal forming processes

Majlessi, Seyed Abdolvahab UMI 1987 국내박사