博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

Critical thinking has long been recognized as a valuable skill, both in education in general and within the world language teaching field specifically. In recent years, critical thinking has been identified as one of the 21st century skills that students need to succeed in modern society (Partnership, 2009). However, there is no clear, unifying definition of the term itself (Paul, 2004), and the definition of critical thinking is debated in many different fields without support from empirical data (Kuhn, 1999). Similarly, critical thinking has been often discussed in the literature as having great potential to facilitate language learning, and particularly to develop language proficiency (Gaskaree, Mashhady & Dousti, 2010; Heining-Boynton & Heining-Boynton, 1992; Hoch & Hart, 1991; Rojas, 2001; Williams, Lively & Harper, 1994). However, this discussion has not been centered around a single, clear definition or been supported by empirical research. This study attempts to fill these gaps by exploring how currently practicing world language teachers define the term critical thinking. Definitions were gathered through a survey of K-16 world language teachers from across the United States and through interviews with individual beginning level German instructors at a large, private university in the western United States. Findings revealed three primary ways in which teachers define critical thinking: first, by identifying characteristics of critical thinking; second, by discussing the thought processes and skills used in the action of critical thinking; and third, by describing the topics about which critical thinking takes place, either on the micro-level, dealing with language itself, or on the macro-level, dealing with real-world issues and themes. Based on these three areas of definition, several pedagogical implications were identified. As critical thinking is integrated as a 21st century skill into the world language classroom, the traditional roles of the teacher may need to transform, the content used in the classroom may need to change, and the activities in which students are asked to engage may likewise need to shift. The integration of these pedagogical implications into the world language classroom as a means to facilitate the development of advanced levels of language proficiency is also discussed.

One of the key security aspects which must be evaluated for cryptosystems is their resistance against side-channel attacks. Masking is a commonly used countermeasure against side-channel attacks, in which the secret to be protected is partitioned into multiple shares using random “masks”. A k-order masked implementation uses k+1 shares. Masked implementations are available for the key encapsulation mechanism of Saber, a finalist in the NIST post-quantum cryptography standardization project. Though Saber has not been selected for standardization, it is similar to the selected CRYSTALS-Kyber, and may therefore have similar leakage. In this thesis, a side-channel attack against a higher-order masked implementation of Saber is attempted. A previous attack on first-order masked Saber using a deep learning-based approach is used as a starting point, though differences in the implementations make the attack not directly applicable to the higher-order case. A byte-wise leakage is found in the higher-order masked implementation, and two different attacks on this leakage point are considered. The first uses the Hamming weights of bytes and is able to recover Hamming weights of individual shares but not the complete message or secret keys from 2nd-order masked Saber. The other uses a method from a different previous side-channel attack in which message bytes are recovered using biased deep learning models. This method successfully recovers all message bytes from 1st-order masked Saber and is shown to successfully recover byte values from 2nd-order masked Saber by training multiple biased models and selecting the best performing models from these, though this also requires a much larger amount of attack data than the 1st-order masking case. This shows that a bytewise leakage in higher-order masked Saber can be exploited using a power analysis side-channel attack, though recovering the complete message and secret keys remains as future work. / En av de främsta säkerhetsaspekterna som måste utvärderas för krypteringsalgoritmer är resistens mot sidokanalsattacker. Maskning är en av de vanligaste åtgärderna för att skydda mot sidokanalsattacker, där känslig information partitioneras i flera delar med hjälp av slumpmässiga värden. En maskning av ordning k använder k+1 delar. Maskade implementationer finns tillgängliga för Saber, en av finalisterna NISTs postkvantkryptografiska standardiseringsprojekt. Saber har inte valts som standard, men har många likheter med den valda standarden CRYSTALS-Kyber och kan därför ha liknande sårbarheter. I detta examensarbete utförs en sidokanalsattack på en högre ordnings maskad implementation av Saber. En tidigare attack på första ordningens maskad Saber används som utgångspunkt, men skillnader i implementationen gör att denna attack inte kan användas direkt. Ett läckage på byte-nivå hittads i den högre ordnings maskade implementationen, och två olika attacker utförs. Den första, som använder Hammingvikten av en byte i meddelandet, kunde erhålla Hammingvikterna för individuella delar av det maskade meddelandet, men inte det ursprungliga meddelandet. Den andra attacken använder en metod från en tidigare sidokanalsattack där meddelanden kunde erhållas med hjälp av partiska djupinlärningsmodeller. Den här metoded kunde användas för att erhålla alla bytevärden från meddelandet med fösta ordningens maskning. Med betydligt mer data och genom att träna ett flertal djupinlärningsmodeller och sedan välja de bästa från bland dessa kunda även vissa bytevärden erhållas från andra ordningens maskning. Detta visar att denna svaghet på byte-nivå kan användas vid en attack på högre ordnings maskad Saber, men det återstår att extrahera hela meddelandet och hemliga nycklar.

L’amélioration des matériaux et des technologies de lentilles de contact a permis le recours de plus en plus fréquent à un type de lentille de contact à grand diamètre reposant sur la sclère : la lentille sclérale (SL). Celle-ci est majoritairement utilisée pour la réadaptation visuelle de patient vivant avec divers types de déformations cornéennes, mais également pour le traitement de maladie de surface oculaire et la correction optique de la simple erreur de réfraction lorsque les autres modalités de lentilles ne peuvent être tolérées. Ce mémoire a pour objectif d’évaluer l’influence de l’asphéricité des surfaces antérieure (ASA) et postérieure (ASP) sur la performance visuelle d’un porteur de SL chez deux groupes distincts : une cohorte de 12 participants sans anomalie cornéenne et une cohorte de 9 participants ayant un diagnostic de kératocône (KC). Lors de l’expérience, quatre différentes SL ayant différents profils d’asphéricité ont été étudiées sur l’œil droit seulement. Pour chaque SL, les mesures d’acuité visuelle à haut contraste (AVHC), l’acuité visuelle à bas contraste (AVHC) et les valeurs moyennes quadratiques (root-mean-square ou RMS) des différents coefficients d’aberrations d’ordres supérieurs (AOS) ont été compilées pour chacun de ces designs aux diamètres pupillaires 3, 4, 5 et 6 mm. Les résultats obtenus suggèrent que l’augmentation de l’ASA d’une SL portée à l’œil droit génère une augmentation de l’aberration sphérique négative, de la coma verticale et horizontale négative chez les deux groupes. L’augmentation de l’ASA entraîne toutefois une augmentation de l’AOS totale et du trèfle total chez les participants sans anomalie cornéenne. Chez le groupe de participants atteint de KC, l’augmentation de l’ASA entraîne une diminution non significative des AOS totales et une augmentation non significative de l’aberration trèfle total. Bien que des études supplémentaires soient nécessaires pour bien comprendre l’influence de l’asphéricité sur les AOS chez les participants atteints de KC, la manipulation de celle-ci permettrait de réduire l’amplitude de certains types d’AOS dans certains cas particuliers. / Improvements in materials and technology have led to the increased use of a large diameter contact lens that rests on the sclera: the scleral lens (SL). These lenses are mainly used for visual rehabilitation of patients with various types of corneal ectasia, for the treatment of ocular surface disease and also for the optical correction of simple refractive error when other lens modalities are not tolerated. The purpose of this dissertation is to evaluate the influence of anterior surface asphericity (ASA) and posterior surface asphericity (ASP) on the visual performance of a SL wearer in two distinct groups: a cohort of 12 participants with no corneal abnormalities and a cohort of 9 participants with a diagnosis of keratoconus (KC). Four different SLs with different aspheric profiles were studied on the right eye only. For each SL, high-contrast visual acuity (HCVA), low contrast visual acuity (LCVA) measurements were measured. The root-mean-square (RMS) values of the higher-order aberration (HOA) Zernike coefficients were also measured for each of these designs for a pupil diameter of 3, 4, 5 and 6 mm. The results of this study suggest that increasing the anterior asphericity of a SL worn on the right eye generates an increase in negative spherical aberration, negative vertical and horizontal coma in both groups. Increasing anterior asphericity leads to an increase in total HOA and total trefoil in participants without corneal anomalies. In the group of participants with KC, increasing asphericity results in a non-significant decrease in total HOA and a non-significant increase in total trefoil aberration. Although additional studies are needed to understand the influence of asphericity on HOA in participants with KC, the manipulation of the anterior asphericity could reduce the amplitude of some types of HOA in some cases.

The rise of connected devices and the internet of things has increased the need for systems capable of transmitting high frequency signals wirelessly. An important part of these systems are the filters. Filters remove signals within unwanted frequency ranges. These filters can be implemented using e.g. periodic structures. In this article, we present a design for such a filter that aims to have a stopband between 3-6 [GHz] using square complementary split ring resonators (CSRR) on a substrate integrated waveguide (SIW). The design is based on a dimensional parametric study. An alternative design based on circular CSRR's is also presented and discussed. The design is validated using a commercially available software and a novel method simulating higher order of modes (HOM). The novel simulation method is shown to be advantageous due to its ability to evaluate the attenuation coefficient of a periodic filter. Additionally, a quadratic CSRR structure was shown to have a larger stopband and a similar attenuation coefficient when compared to circular CSRR structure when applied on a SIW. Furthermore, an impedance matching structure for the both CSRR filters were designed and both filters were simulated. / Förekomsten av uppkopplade enheter och användandet av sakernas internet har ökat behovet av system som kan sända högfrekventa signaler trådlöst. En viktig del av dessa system är filter, som eliminerar signaler inom oönskade frekvensband. Dessa filter kan implementeras med periodiska strukturer. I denna rapport presenterar vi en design för ett sådant filter med ett stoppband mellan 3-6 [GHz] som använder sig av kvadratiska "complementary split ring resonators" (CSRR) på en "substrate integrated waveguide" (SIW). Designen är baserad på en geometrisk parametrisk studie. En alternativ design som använder sig av cirkulära CSSRs presenteras och diskuteras. Den föreslagna designen valideras med en kommersiellt tillgänglig och en egenframställd metod vid namn "higher order of modes" (HOM) metoden. Den egenframställda simulationsmetoden visas vara fördelaktig då den är kapabel att evaluera filtrets attenuationskoefficient. Utöver detta visas att en design baserad på kvadratiska CSRRs vara fördelaktig då den genererar ett större stoppband och liknande attenuationskoefficient jämfört med den cirkulära CSSR designen vid tillämpning på en SIW. Fortsättningsvis presenteras en matchande struktur för båda filter varpå båda kompletta filter simuleras. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

One group of games studied within game theory are grid-based pursuit evasion games of imperfect information. A pursuit evasion game is in essence a game where there exists a set of pursuers which have as their objective to capture a set of evaders. This thesis aims to develop a formalisation of this type of games as well as describing and integrating vital game theoretical concepts such as order of knowledge into this game. With the developed formalism at hand, the concept of knowledge-based strategies is then introduced, which is essential when searching for the way to play the game most efficiently. The formalisation of the game is then followed by a simulation, measuring the performance of some older and some newly developed knowledge-based strategies. The thesis concludes that the formalisation is applicable on a more general class of pursuit evasion games and enables a wider study of the game. The simulation results indicate that knowledge-based strategies of higher order do not always perform better compared to simpler strategies of lower order of knowledge. Furthermore, strategies which allow for communication between agents are found to be superior to communication-less strategies. / En typ av spel som studeras inom spelteori är rutnätsbaserade jakt-flykt-spel med ofullständig information. Ett jakt-flykt-spel går ut på att det existerar en samling jagande aktörer som försöker fånga en samling flyende aktörer. Denna uppsats söker utveckla en formalism för denna typ av spel såväl som att beskriva och integrera ett antal nyckelkoncept inom spelteori såsom kunskapsordning. Med hjälp av den utvecklade formalismen, framställs så kallade kunskapsbaserade strategier, vilka är av fundamental vikt i sökandet efter sätt att spela spelet på det effektivaste sättet. Kapitlet om formalismen följs sedan av simuleringar där några äldre och några nyare kunskapsbaserade strategier prövas. Slutsatsen dras att den nya formalismen kan vara applicerbar på en bredare samling jakt-flykt-spel än den initialt påtänkta. Vidare underlättar formalismen en generalisering till andra sätt att beskriva spel. Simulationsresultaten indikerar att kunskapsbaserade strategier av högre ordning inte alltid presterar bättre än enklare strategier av lägre ordning. Till yttermera visso visar sig kommunikationslösa strategier vara underlägsna strategier som tillåter kommunikation. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

Traditional teacher-centered methods of lectures and PowerPoint presentations are commonly used when teaching secondary social studies, yet these methods continually prove to be boring for most high school students and neglect to teach critical thinking skills. Student-centered methods are different than teacher-centered methods because these methods incorporate several learning styles, cooperative activities, and even technology in order to engage the student and promote critical thinking skills. Critical thinking is important for students to master because it gives them the skills to move past the obvious and make individual connections with the text. The intent of this thesis was to explore the effectiveness of integrating student-centered methods in high school social studies classrooms as a means of promoting critical thinking skills. All students were given the same pretest and posttests. Students were divided into three groups: one was taught using student-centered methods, one was taught using teacher-centered methods, and one was the control group and was not directly taught by anyone. Based on analyzing students' posttest scores compared to their pre-test scores, student-centered teaching produced a higher average score increase, though all methods had students who scored higher, and students whose scores remained constant. Evidence and student feedback showed that continued future research should be conducted to see if student-centered methods should be used throughout all secondary social studies classrooms to promote critical thinking.

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