Study on lens design methods for improving the viewing properties of the integral imaging system degraded by lens-array aberrations : 렌즈 어레이의 수차에 의하여 저하되는 집적 영상의 시야 특성을 향상시키는 렌즈 디자인에 대한 연구

Matheus Farias Miranda 서울대학교 대학원 2015 국내석사

Integral imaging (InIm) is a promising three-dimension (3D) display technique because it can display 3D images with vertical and horizontal parallax without the need for any special glasses. InIm requires a lens-array in front of the display panel in order to integrate the elemental images (EI) into the 3D image. Conventionally the elemental lenses have spherical surface profiles, thus they suffer from intrinsic lens aberrations such as spherical aberration and astigmatism. Aberrations affect the ability of the lens to focus light in a single point, or to collimate light from a point source. In InIm, this results in a loss of image quality of the elemental images and reconstructed image due to distortions. The viewing characteristics of the InIm system, such as viewing angle and image resolution, are also affected by aberrations. In this work the author proposes two methods designing aberration-minimized lens-array. The first method is based on the splitting and bending of the lens-array’s elemental lens such that aberration balancing can be achieved. Simulations are performed and the effectiveness of this method is demonstrated by comparing the designed lens-array with a standard spherical lens-array of same properties. In the second method the author describes the design process of a custom aspherical lens-array which has minimum spherical aberration. The design, optimization, and fabrication processes are described. Experiments are presented and compared with the computer simulations. A thorough analysis of the results is performed and solutions to the issues encountered are proposed.

Human rights approach to cross-border parental child abduction cases : learnings from the European court of human rights

Andrade Mendes, Matheus Filipe Graduate School, Korea University 2022 국내석사

The present research builds on the growing importance of discussing human rights issues in family relations, a constant effort for researchers and legal practitioners dealing with international family law (IFL) cases. One of the most interesting practice areas of IFL is international parental child abduction. It is situated in the convergence area between international human rights law and IFL, raising issues of distinctive legal nature, most of them in a transboundary context. It is also one of the areas where the best interests of the child play a central role. Thus, this work aims to evaluate the summary return mechanism of the Convention of 25 October 1980 on the Civil Aspects of International Child Abduction (1980 Hague Convention) through the lens of international human rights law. More specifically, the practical operation of the 1980 Hague Convention will be analyzed from the perspective of the right to respect for private and family life, as established by the 1950 European Convention of Human Rights (ECHR), and the right of the child to have his or her best interests taken as a primary consideration, as established by the 1989 Convention on the Rights of the Child (CRC). For that end, relevant jurisprudence of the European Court of Human Rights (ECtHR) on the issue of child abduction will be raised. Since 2001, the Court has issued more than 80 judgements and decisions regarding child abduction. The only two cases to be appreciated by the Grand Chamber of the Court – Neulinger and Shuruk v Switzerland (2010) and X v. Latvia (2013), set out important general principles for the appreciation of child abduction cases under the 1980 Hague Convention. These principles highlight the efforts of the Court in harmonizing the interpretation of the 1980 Hague Convention with the ECHR and the principle of the best interests of the child. This thesis argues that the prompt return to the habitual residence mechanism proposed by the 1980 Hague Convention remains to be the solution for a considerable number of international child abduction cases, and there are efforts towards increasing compatibility with international human rights law. 이 연구는 가족 관계에서의 인권문제에 대해 다루는 국제가족법을 살펴본다. 국제가족법의 가장 중요한 주제 중 하나는 국제적 아동탈취다. 따라서 이 논문은 1980년 10월 25일 국제적 아동탈취의 민사적 측면에 관한 헤이그협약 (Hague Convention on the Civil Aspects of International Child Abduction; 이하 1980년 헤이그 협약) 에서 규정하고 있는 아동이 불법으로 타국으로 탈취되어 간 경우 신속히 이전의 상거소지국으로 돌려보내는 내용에 대해 국제인권법과의 비교를 통해 평가한다. 구체적으로 동 협약에 대해 유럽인권협약 제8조에서 규정한 사생활과 가족생활, 주거 및 통신을 존중받을 권리와 유엔아동권리협약 제3조 제1항에서 아동 최선의 이익 원칙이라는 관점에서 분석한다. 이를 이해 아동 탈취 사건에 관한 유럽인권재판소의 판례들을 검토한다. 2001년부터 유럽인권재판소는 국제적 아동탈취에 관한 80건 이상의 판결을 내렸다. 대재판부 (Grand Chamber)에서 판결 받은 두 사건인 Neulinger and Shuruk v Switzerland (2010) 및 X v. Latvia (2013)는 1980년 헤이그 협약에 따른 아동탈취 사건의 평가에 대한 중요한 일반 원칙을 제시한다. 이러한 일반 원칙은1980년 헤이그 협약의 해석과 위에서 언급한 국제인권법 원칙과의 균형을 맞추려는 유럽인권재판소의 노력이 강조된다. 이 논문은 현재에도 상당수의 국제 아동 탈취 사건에 대해 1980년 헤이그 협약의 규정이 해결책이 될 수 있다고 주장한다. 또한 동 협약에서 아동을 원래의 상거소지국으로 신속하게 돌려보내는 내용이 국제인권법과 양립하는 방향으로 해석되고 발전하고 있음을 살펴본다.

Failure mode analysis of PV modules and insulators in corrosive conditions to enhance reliability

De Assis Rabelo, Matheus Sungkyunkwan University 2022 국내석사

In this study, some degradation and failure modes of Photovoltaic modules and porcelain insulators under corrosive environments are discussed. These 2 components are widely used worldwide and essential to provide sustainable and cost-effective distribution of electric energy. However, their durability has become a major concern. In the case of Photovoltaic (PV) modules, manufacturers typically provide customers with long warranty periods (20-25 years), which forces manufacturers to improve the reliability of their products. As for porcelain insulators, the maintenance costs may account for more than 50% of the total budget. Extending the life of these components signifies longer maintenance intervals and ensures that the product fails only after the warranty period has ended. In this work, porcelain insulators were collected from various locations in South Korea and classified according to their length of service. Mechanical and electrical load tests were performed, and the failure load and damaged region were recorded for each specimen. The fast degradation of the pin in porcelain insulators exceeding 50 years in operation was notable because there was no pin breakage among the samples in service for less than 50 years. Moreover, the failure of 73.68% of all porcelain insulators in service for 54 years occurred in the pin. The average failure load of these samples was 14% lower than that of samples in use for 45 years. To confirm the pin’s deterioration mechanism over time, a mechanical analysis of the reduction in the pin cross-section was performed using the finite element analysis method. Applied loads of 45, 75, and 95 kN resulted in stresses of 170, 285, and 350 MPa, respectively, in the bottom half part of the pin exposed to air. To calculate the stresses due to corrosion, the model was redrawn considering diameter reductions of 0.6, 1.2, 1.8, and 2.4 mm. The stress fields were found to considerably affect the corroded zone even in the case of the sample with a 0.6-mm reduction in diameter. Accordingly, a novel degradation mechanism is proposed. Alongside, the corrosion of passivated emitter and rear cells (PERC) is also investigated in this study using both experimental and numerical methods to identify areas susceptible to higher corrosion rates and its effect on the degradation of electrical parameters. The effect of the acetic acid concentration and relative humidity is investigated. A rapid decrease in ISC and RSH is observed with increasing acetic acid concentration in the solution. As a result, in the first 100 hours of exposure, the power drop was faster in the cases of 10 and 20% acetic acid concentration, dropping by more than 30%. The simulation reveals that the highest corrosion rates are found at the front ribbons in contact with the busbar (100 A/m2), at the rear Al surrounding the Ag contact (60 A/m2) and at the silicon (20 A/m2) when relative humidity is 85%. Through more experiment setups, it was found that the reliability bottleneck of PERC solar cells under corrosion lies in the rear aluminum around the silver contact and a degradation mechanism is proposed. After that, a novel method to produce corrosion-resistant solar cells is presented. 이 연구에서는 부식성 환경에서 PV 모듈 및 애자의 일부 열화 및 고장 모드에 대해 논의합니다. 이 두 가지 구성 요소는 전 세계적으로 널리 사용되며 전기 에너지의 지속 가능하고 비용 효율적인 분배를 제공하는 데 필수적입니다. 그러나 내구성이 주요 관심사가 되었습니다. PV 모듈의 경우 제조업체는 일반적으로 고객에게 긴 보증 기간(20-25년)을 제공하므로 제조업체는 제품의 신뢰성을 향상시켜야 합니다. 자기 단열재의 경우 유지 비용이 전체 예산의 50% 이상을 차지할 수 있습니다. 이러한 구성 요소의 수명을 연장하면 유지 관리 간격이 길어지고 보증 기간이 종료되기 전까지 제품의 고장을 방지할 수 있습니다. 이 작업에서는 한국의 여러 곳에서 애자를 수집하여 사용 기간에 따라 분류했습니다. 기계적 및 전기적 부하시험을 수행하였으며, 각 시편에 대하여 파손하중 및 손상부위를 기록하였습니다. 50년 이상 사용된 자기 절연체에서 핀의 빠른 열화는 50년 미만 동안 사용된 샘플 중 핀 파손이 없었기 때문에 주목할 만합니다. 더욱이 54년 동안 사용된 전체 애자의 73.68%가 핀에서 발생했습니다. 이 샘플의 평균 파손 하중은 45년 동안 사용된 샘플의 평균 파손 하중보다 14% 낮습니다. 시간 경과에 따른 핀의 열화 메커니즘을 확인하기 위해 유한 요소 해석 방법을 사용하여 핀 단면 감소의 기계적 해석을 수행했습니다. 45, 75, 95 kN의 하중을 가했을 때 공기에 노출된 핀의 하단 부분에 각각 170, 285, 350 MPa의 응력이 발생했습니다. 부식으로 인한 응력을 계산하기 위해 0.6, 1.2, 1.8 및 2.4mm의 직경 감소를 고려하여 모델을 다시 작성했습니다. 응력장은 직경이 0.6mm 감소한 샘플의 경우에도 부식 영역에 상당한 영향을 미치는 것으로 나타났습니다. 따라서 새로운 분해 메커니즘이 제안됩니다. 이와 함께 PERC 태양 전지의 부식도 실험적 및 수치적 방법을 사용하여 더 높은 부식률에 민감한 영역과 전기적 매개변수의 저하에 미치는 영향을 식별하여 이 연구에서 조사됩니다. 아세트산 농도와 상대 습도의 영향을 조사되었습니다. ISC 및 RSH의 급격한 감소는 용액의 아세트산 농도가 증가함에 따라 관찰됩니다. 그 결과 노출 첫 100시간 동안 초산 농도가 10%와 20%인 경우 파워 강하가 더 빠르게 30% 이상 떨어졌습니다. 0wt% 아세트산 조건의 경우 양자 효율 하락은 그리드 전기 저항 증가와 핑거 및 리본 주변의 산화물 오염으로 인한 음영으로 인한 작은 기여로 인해 발생합니다. 아세트산이 존재하면 션트로 인한 전류 누출로 인해 더 많은 손실이 추가되며 이는 또한 캐리어 수집에도 영향을 미칩니다. 시뮬레이션은 상대 습도가 85%일 때 버스바와 접촉하는 전면 리본(100A/m2)과 Ag 접촉을 둘러싼 후면 Al(60A/m2)에서 가장 높은 부식 속도가 발견된다는 것을 보여줍니다. 더 많은 실험 설정을 통해 부식된 PERC 태양 전지의 신뢰성 병목이 은 접점 주변의 후면 알루미늄에 있다는 것을 발견했으며 열화 메커니즘이 제안되었습니다. 그 후, 내식성 태양 전지를 생산하는 새로운 방법이 제시됩니다.

Using reporter bacteria to study the bioavailabillity of pollutants in aqueous environments

Jaspers, Marco Cornelis Matheus Swiss Federial Institute of Technology Zu@rich 2002 국내박사

Factors affecting the successful use of Web sites

Matheus, Anne State University of New York at Albany 2009 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Every second of every minute of every day, many people search the World Wide Web for information. People are less likely to use hard copy telephone books, encyclopedias, libraries, or other traditional methods of research. They access these traditional resources through web based portals. People use the web to find restaurants, go on vacation, to answer health questions, and students use the web for everything. How do people make judgments about the accuracy or reliability of information they get from a web site? On what basis do they make a decision to use a particular web site? Current studies conducted in a Canadian university indicate that people make a decision in less than half a second about whether they are going to look at a web site or not. Methods to study the commercial aspects of the World Wide Web (WWW) have been the primary focus of research in a Web context. In a systematic effort to study the success measures related to information use of the WWW, a model was developed and tested. The process included a pre-pilot study to develop a questionnaire and a standardized protocol for administration of the questionnaire. A pilot study was then conducted to test the outcomes from the pre-pilot and determine if the protocol was satisfactory. The full study was subsequently conducted. The Web Success Model is based on the IS Success Model, the Technology Acceptance model, and the Unified Theory of Acceptance and Use of Technology model as well as research in the areas of information quality and system design. The model was analyzed using Structural Equation Modeling which allowed for confirmatory factor analysis of the constructs and an identification of the relationships between the constructs with path coefficients. Prior research has focused on the design; including the graphics, navigation, structure, and flow of the web site. This study focuses on the human factors that relate to the use of the web by college students looking for information to answer course related content questions.

Development of high concentration cetuximab formulations using ultrafiltration and precipitation techniques

Matheus, Susanne Ludwig-Maximilians Universität 2006 국내박사

Assessing interventions for reducing gender-based occupational stereotypes: A multi-method study comparing the Implicit Association Test to indirect and explicit measures of stereotypes, and an examination of sex roles and entity versus incremental lay theories of social perception

Matheus, Carolyn C State University of New York at Albany 2010 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Certain occupations are often stereotyped as feminine (e.g., elementary school teacher) while others are stereotyped as masculine (e.g., engineer) (White, Kruczek, Brown, & White, 1989; White & White, 2006). This study proposed using multiple methods to assess stereotypical judgments about the masculinity and femininity of five occupations: engineer, law enforcement officer, accountant, fashion designer, and elementary school teacher. Implicit, indirect, and explicit assessments were used to measure gender-based stereotypes of occupations to examine similarities or differences between the different methods. Implicit assessments involve measuring automatic evaluations to stimuli, while indirect assessments involve gender-ratings of attributes associated with occupations. Both implicit and indirect measurements leave participants relatively unaware of what is being measured. On the other hand, explicit assessments (e.g., surveys) make the nature of the study known because people are explicitly asked questions pertaining to the variables of interest. The current study constructively replicated and improved upon White and White's (2006) study of implicit and explicit occupational gender stereotypes by accounting for several limitations of White and White's study. White and White found engineering to be characterized as a masculine occupation, elementary school teacher was characterized as a feminine occupation, and accountant was characterized as a gender neutral occupation, regardless of whether the occupations were measured implicitly or explicitly. Their study was limited by the use of college students as the sample, as well as their limited range of occupations. The current study improved upon White and White's study by using a sample of working adults, and by analyzing two additional occupations: law enforcement officer and fashion designer. Gender-based occupational stereotypes were examined using the Implicit Association Test (IAT), an indirect measure, as well as bi-polar and uni-polar explicit scales. The IAT implicitly measured stereotypes that people may not express on explicit self-report measures. Two interventions for reducing stereotypes were also examined in an experimental design. Participants were either shown a gender counter-stereotypical picture or given instructions to imagine their own image of a "strong woman." The interventions were intended to reduce gender-based stereotypes of occupations by introducing relevant counter-stereotypic information. However, the interventions were not found to be effective. Two factors were examined as moderators of the impact of the interventions on reducing gender-based stereotypes of occupations. First, a person's theory about the fixedness or malleability of traits is thought to affect stereotypical judgments. Participants completed the Implicit Person Theory Measure to assess whether the participants perceived traits as fixed (entity theory) or malleable (incremental theory). Participants' theories of traits were hypothesized to moderate the effects of the interventions. In particular, persons who adopt an entity theory were predicted to be less influenced by counter-stereotypic information (e.g., a counter-stereotypic picture or the use of counter-stereotypic mental imagery) aimed at reducing stereotypes. On the other hand, persons who adopt an incremental theory were predicted to be more influenced by interventions aimed at reducing stereotypes. Lay theory was not found to moderate the impact of interventions on stereotype reduction, possibly a result of the interventions themselves. Second, the current study examined respondents' sex role as a factor that potentially moderates the impact the interventions have on reducing stereotypes. The extent to which people describe themselves in terms of masculine characteristics (e.g., assertive, aggressive, independent) or feminine characteristics (e.g., gentle, compassionate, sensitive to the needs of others) may influence interventions aimed at reducing stereotypes. For example, people adopting a masculine sex role may be more likely to accept stereotypes that certain occupations are better suited for men, while people adopting a feminine sex role may be more likely to accept stereotypes that certain occupations are better suited for women. The Bem Sex Role Inventory (Bem, 1974) was used to assess gender role perceptions. Sex role was not found to be a moderator of the impact of interventions aimed at reducing stereotypes. Finally, the different implicit, indirect, and explicit measures were examined and compared to one another. A variance index was created for each of the four scales to generate single scale scores that could be compared to one another and the IAT. Results indicate the implicit and explicit measures may be measuring different constructs and highlight the important of using multiple methods to accurately capture complex information such as gender-based stereotypes about occupations.

Mechanics of Biologically Inspired Structures and Flexible Mechanical Metamaterials

Fernandes, Matheus C Harvard University ProQuest Dissertations & Theses 2021 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

In this dissertation, I focus on exploring biologically inspired structures and the mechanics of flexible porous metamaterials by utilizing both experimental and computational methods.For the biologically inspired structures portion of this dissertation, namely chapters 2 and 3, I focus on the architectural details of the glassy skeletal system from the hexactinellid sponge, Euplectella aspergillum. In chapter 2, I show that this sponge's meso-scale skeletal system, consisting of a square-grid-like lattice architecture overlaid with a double set of crossed diagonal bracings, exhibits the highest buckling resistance for a given amount of material when compared to related lattice structures. These findings are further confirmed thorough an evolutionary optimization algorithm, through which I demonstrate that the sponge-inspired lattice geometry occurs near the design space's optimum material distribution.At another level of structural hierarchy, in chapter 3 I show that its complex maze-like organization of helical ridges that surround its main skeletal tube, not only provide additional mechanical reinforcement, but perhaps more significantly, deliver a critical hydrodynamic benefit by effectively suppressing von Karman vortex shedding and reducing fluctuations in lift forcing over a wide range of biologically relevant flow regimes. By comparing the disordered sponge ridge geometry to other more symmetrical strake-based vortex suppression systems commonly employed in engineering contexts ranging from antennas to underwater gas and oil pipelines, I find that the unique maze-like ridge organization of the sponge can completely suppress vortex shedding rather than delaying the shedding to a more downstream location. These findings highlight the sponge ridge design's potential benefit in engineering applications.Lastly, in chapter 4, I utilize similar experimental and computational methods to study the response of porous mechanical metamaterials with well-defined periodicity for their ability to exhibit complex behavior as a result of their non-linear deformation. Although it is well known that buckling-induced planar transformations occur in 2D porous metamaterials, here I explore the emergence of 3D morphologies triggered by mechanical instabilities in an elastomeric block with tilted cylindrical holes. I demonstrate that the 3D deformation of these structures can be leveraged to tune surface properties including friction and light reflection, thus providing a new experimental platform for investigating deformation-dependent dynamics for tribological and optical applications.

Investigating the Potential of Supplementary Nitrate and Monensin as Dietary Additives for Enteric Methane Mitigation in Ruminants

Capelari, Matheus Gabriel Maidana Michigan State University ProQuest Dissertations & 2018 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Enteric CH4 production from ruminant livestock is the largest source of anthropogenic CH4 emissions in the United States and in most countries with significant livestock production. Because animal products from ruminants are an important part of the diet and CH4 from ruminant animals contributes to greenhouse gas (GHG) emissions, finding ways to reduce CH4 from the livestock production are essential to long-term viability of ecosystems and consumer food choices. In addition, CH4 represents a significant dietary GE loss and reduction in methanogenesis can result in improved feed utilization. Supplementing the diets of ruminants with nitrate salts consistently decrease CH4 production without signs of microbial adaptation in the long-term. Nitrate reduction is a biochemical process that consumes H2, which, in the rumen, is the substrate used by methanogenic archaea for energy production. Monensin sodium has been extensively used in ruminant production because it increases feed conversion and the reduction in CH4 production from monensin feeding is mainly related with more efficient fermentation and reduced protozoa numbers. Therefore, nitrate and monensin affect methanogenesis through different mechanisms. The objective of this study was to evaluate if the combination of nitrate and monensin could additively reduce CH4 production without compromising animal health and performance. A series of experiments were conducted to test the effect of additives on enteric CH4 production and ruminal fermentation parameters. Independent of diet composition, nitrate and monensin additively reduced CH4 production with in vitro models, with maximum reduction of approximately 90% on batch culture trials and 45% on semi-continuous culture fermenters. In batch culture trials the combination of additives at higher doses (2.5% of nitrate in the diet and 6 mg of MON per L of culture media) reduced digestion of feeds. In the semi-continuous fermenters a similar effect on nutrient digestion was observed when additives were combined in higher levels tested (2.5% of nitrate in the diet and 4 mg of monensin per L of culture media), but no effect was observed on VFA production. An intermediary dose of nitrate (1.5% of DM) was tested in growing steers and a significant reduction of 10% for CH4 production was observed. Animals fed nitrate did not demonstrate any clinical sign of toxicity during the experiment with methemoglobin levels similar to control animals. Monensin reduced CH4 production by growing steers by 5% when compared to control. When combined, additives reduced CH4 production by approximately 16% without affecting ruminal fermentation, demonstrating a potential for utilization of additives in the diet of ruminants as a means of CH4 abatement. Long-term performance trials coupled with CH4 measurements are needed to confirm that this strategy does not impair animal performance and are able to sustain reduction on CH4 levels for longer periods of time.

Economics and Computation in Decentralized Systems

Xavier Ferreira, Matheus Venturyne Princeton University ProQuest Dissertations & Thes 2021 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Algorithmic game theory studies algorithmic design under incentive constraints, and, in its foundations, the contributions between computer science and economics in this area go both ways. In one direction, economics provides new perspectives in designing secure computer systems: real-world adversaries are often not intentionally malicious but rather rational and economically driven. In the other direction, the emergence of decentralized applications poses challenges to traditional assumptions from economic theory.Here, we study the problem of designing decentralized applications implemented by autonomous rational agents. First, we provide efficient constructions of credible and strategyproof optimal auctions where neither bidders nor the auctioneer has the incentive to be strategic, overcoming prior impossibility results from the literature. Our auctions are revenue optimal, which shows the auctioneer need not sacrifice revenue to implement a more transparent auction.Blockchains are a promising tool for designing generic decentralized applications, but constructions relying on Proof-of-Work (PoW) are energy inefficient. We show that energy-efficient alternatives, notably Proof-of-Stake blockchains, can approximate the incentive guarantees of PoW when given access to public randomness. Thus we reduce the problem of designing energy-friendly blockchains to designing a trusted public source of randomness such as the NIST randomness beacon.Third, we show the connections between credible auction design with the problem of allocation block space in blockchains through a transaction fee mechanism. We propose dynamic mechanisms that provide a better user experience than the status quo and are robust manipulation from miners. Under natural conditions, we provide stability and welfare guarantees at equilibrium. In the last part, we investigate the role of policy and regulation in designing a secure decentralized system. Although technical advances have contributed significantly to the security of Internet systems, the proliferation of large-scale DDoS attacks shows how incentive misalignment between users and manufacturers of computer devices drives the risk of computer vulnerabilities. Optimal regulations might require intervention from users and manufacturers and might be highly complex. However, we give theoretical evidence that interventions that impact only users or manufacturers can approximate the outcome of optimal ones.