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Research on memory often describes the remarkable longevity of music. However, memory for music is not uniform. Cook (1987) found that participants were not able to tell apart excerpts that modulated from those that did not when the excerpt was longer than 1 minute in length. This suggests that participants were no longer able to remember, and compare, musical keys after a relatively short period of time. Farbood (2016) and Woolhouse et al. (2016) further explored the limitations of memory for tonal structures finding that, in fact, harmonic memory only lasts up to 21 seconds after modulation. However, this research was done using homophonic stimuli—arpeggios or quarter-note chords—that may not be representative of the music participants would be listening to regularly. The focus of this project was to explore how the addition of certain musical features, such as melodic or rhythmic figurations, may influence harmonic memory. Observing these possible influences may provide us with insight into the processes responsible for auditory memory and how it differs from other domains, such as speech or vision. Chapter 1 explores prominent memory literature and music cognition experiments that support, or address concerns with, common memory models. Here, I introduce a cognitive system which reconciles music research with models by memory specialists such as Baddeley and Snyder. Chapter 2 presents a detailed account of background empirical literature, including Farbood (2016) and Woolhouse et al. (2016). Though fundamental to the exploration of temporally nonadjacent harmonic memory, this research is potentially limited in its generalizability due to the homophonic nature of the stimuli. Chapter 3 explores this limitation by testing the effects of adding surface features—melodic and rhythmic components often used for elaboration in composition—on memory for large-scale tonal structures. Results found that harmonic memory is, indeed, enhanced and prolonged by these elaborative components, lasting up to 33 seconds, well past the limit found in previous research. Farbood (2016) further claimed that harmonic memory is significantly interrupted by new, highly harmonic excerpts. However, results from Woolhouse et al. (2016), Spyra et al. (2021) and those from Chapter 3 all question this claim as they employed stimuli that was highly harmonic. Chapter 4 investigates the contradiction by testing whether functional diatonic, functional chromatic, or random sequences degraded harmonic memory for an original key. Functional diatonic intervening information resulted in increased harmonic memory, directly contradicting Farbood’s original findings. In Chapter 5, these results are explored in terms of prominent memory models in the field of cognition, supporting standard models of memory such as that by Baddeley and Hitch (1974) or Atkinson and Shiffrin (1968), as well as my proposed cognitive system. This is further elaborated by discussing the process of undergoing a musical judgement task from perception through to decision-making. In summary, this project suggests that more generalizable stimuli containing realistic musical features produce a significant boost in harmonic memory. Furthermore, this arguably calls into question standard practices in analysis that categorize surface features as hierarchically less important than ’deeper’ harmonic events, and thus, potentially less important from a cognitive perspective. Which is to say, this evidence suggests that these features may play a vital role in remembering nonadjacent harmonic structures. / Dissertation / Doctor of Philosophy (PhD) / Memory for music is often celebrated for its longevity. Music is a complex stimulus, however, and not all of its characteristics are remembered equally well. Past research has found that participants were not able to remember musical keys after a surprisingly short period of time: Farbood (2016) and Woolhouse et al. (2016) found that harmonic memory—i.e., memory for a key—lasts up to 21 seconds after a key change. Compared to nursery rhymes remembered from childhood bedtimes, this is remarkably limited. Yet this research did not fully explore which musical characteristics affect harmonic memory as it was done using simple musical stimuli: compositions made of blocks of chords. Whereas a string of chords might sound pleasant, it may not be representative of the type of music that people listen to regularly (with complex melodies and instrumentation). The focus of this project was to explore musical factors, such as melodies or rhythms, and measure how they interact with musical memory. Observing specific aspects of the stimulus gives us a window into the complexities of human memory, particularly that of the auditory domain. Chapter 1 provides an overview of memory literature with a focus on common memory models and the musical research that supports them or contributes to their development. Here, I propose a cognitive system which integrates prominent models that otherwise describe different stages of processing complex auditory stimuli. Chapter 2 presents a detailed account of background empirical literature. This provides a basis for a series of experiments outlined in Chapters 3 and 4. These experiments investigate how components of music influence harmonic memory. Components include Surface Features, or ornamentations in music such as melodies or rhythms, and Harmony, the structure of the key itself which can make an excerpt sound more, or less, familiar. Results suggest that memory is significantly enhanced and prolonged by the addition of surface features. Furthermore, harmony that most resembles culturally familiar compositional practices also provides a memory boost when compared to random or somewhat ambiguous sequences. In Chapter 5, the implications of these results are explored with regards to the general memory models discussed in Chapter 1. Results support standard models of memory and my proposed cognitive system, as demonstrated by following the processing of my experimental musical stimuli from sound to executive function. This project suggests that more complex and musically realistic stimuli produce a significant memory boost. This puts into question traditional practices in music analysis which separate surface features into hierarchically less important positions when, in fact, the musical surface may be vital to our processing of auditory stimuli.

Purpose – Leveraged exchange traded funds (ETFs) have become increasingly popular since their introduction in 2006. In recent years, options on leveraged ETFs have been promoted as a means of enhancing returns and reducing risk. The purpose of this paper is to examine the interchangeability of S&P 500 ETF options with leveraged S&P 500 ETF options and to what extent these options allow investors to manage their risk exposure. Design/methodology/approach – With increasing liquidity for these fund’s options, simple option strategies such as covered calls and protective puts can be implemented. This study derives call-call and put-put parity between options on the underlying index and the associated leveraged ETFs. The paper examines comparative measures of return and risk on the underlying indices, along with covered call and protective put positions. Findings – Using the formulations derived, this study shows options on non-leveraged ETFs or on the underlying index can be substituted for leveraged ETF options. Empirical results suggest substituting options on leveraged ETFs with options on the underlying index or index ETF give comparable results, but can differ as the realized leverage ratio over time differs from projected values. Originality/value – This study is the first to the authors’ knowledge that investigates option strategies on leveraged and inverse ETFs of equity indices. It is also the first to derive call-call and put-put parity relations between options on ETFs and related leveraged and inverse ETFs. The results contribute to securities issuance, investment strategies, and option parity relations.

This dissertation consists of two parts. In the first chapter, we examine the relative performance of four options-based investment strategies versus a buy-and-hold strategy in the underlying stock. Specifically, using ten stocks widely held in 401(k) plans, we examine monthly returns from strategies that include a long stock position as one component. These strategies are long stock, covered call, protective put, collar, and covered combination. Ignoring early exercise for simplicity, we find that the covered combination and covered call strategies generally outperform the long stock strategy, which in turn generally outperforms the collar and protective put strategies regardless of the performance measure considered. Clearly, from the first chapter, strategies that involve writing options, in general, outperform the ones buying options. The second chapter provides a detailed study of the conditions where option writers can maximize returns while minimizing risk. The nonlinear nature of time value decay in options suggests that, theoretically, holding short positions only when the speed of time decay is high might improve the performance of option writing strategies. We examine monthly returns from five option strategies without a position in the underlying asset. These strategies are: short straddle, short strangle, short guts, “crash-neutral” short straddle, and long iron butterfly. The results from two portfolios are compared: a “benchmark” portfolio using standard SPX options that expire the following month and a weekly portfolio using SPXW options that expire at the end of the weekly holding period. The short strangle strategy with weekly options consistently outperforms the other strategies with both standard and weekly options, even after accounting for transaction costs. This finding suggests that short-dated out-of-the-money options can be useful in improving the risk-return characteristics of an option writing strategy. In an effort to improve the performance of the short straddle strategy, this chapter introduces an extremely short holding period portfolio, by stitching together three weekly option expirations into one week. Although the straddle still underperforms relative to the short strangle, the performance of the short straddle is improved by entering the market 15 minutes before the close and by using the extremely short holding period portfolios.

Les tests de dispositifs de communication sans fil peuvent être réalisés en utilisant des simulations numériques ou des sondeurs de canaux. Bien que ne reflétant pas un environnement électromagnétique réaliste, une chambre réverbérante peut néanmoins émuler un canal de propagation comparable à un cas réel si l’on modifie convenablement ses propriétés. Les propriétés des signaux générés dans une chambre réverbérante sont fonction de différents paramètres. Au cours des trois années de thèse, nous avons analysé et mis en oeuvre plusieurs techniques pour mesurer et contrôler ces paramètres à l’intérieur d’une chambre réverbérante. D’abord, différents estimateurs du facteur K sont testés et leurs propriétés sont évaluées. Nous présentons les limites de fonctionnement utiles dans lesquelles différents estimateurspeuvent être utilisés. Ensuite, nous proposons deux nouveaux estimateurs qui utilisent comme données d’entrée seulement l’enveloppe du signal. Ils apportent en outre des améliorations sur la gamme des valeurs détectables du facteur K. Une des possibilités pour contrôler un canal de propagation à l’intérieur d’une chambre réverbérante est d’utiliser des matériaux absorbants. Nous présentons une méthode pour estimer la surface équivalente moyenne d’absorption en utilisant une seule antenne. Cette méthode exploite la mesure de la bande de cohérence du canal de propagation. Ensuite, nous étendons notre analyse à la prédiction de la surface équivalente moyenne d’absorption lorsqueles dimensions géométriques et les propriétés électromagnétiques des absorbants sont connues. On crée ensuite un modèle de canal de propagation en exploitant les régimes transitoire et permanent du signal. Avec ce modèle, selon les informations disponibles, on peut extraire le facteur K, la surface équivalente moyenne d’absorption et différents paramètres temporels (i.e., profil de l’étalement des retards). Nous poursuivons avec deux applications possibles des chambres réverbérantes. Tout d’abord, on évalue le gain d’une antenne à partir de mesures du coefficient de réflexion decette antenne. Nous étendons notre analyse à l’évaluation du diagramme de rayonnement de l’antenne et de son erreur d’estimation. Nous estimons aussi la désadaptation de l’antenne et son ouverture à 3 dB. La deuxième application porte sur l’évaluation du gain de diversité dans la chambre réverbérante. Nous isolons les influences des efficacités des antennes, des puissances des composantes brassées, et des facteurs K sur l’évaluation du gain de diversité.On obtient une relation simple de la corrélation de puissance en fonction de la corrélation complexe lorsque les facteurs K sur différents branches ne sont pas identiques. Nous montrons que lors d’un fort déséquilibre de facteur K il est impossible de conclure sur le gain de diversité à partir de la seule évaluation de la corrélation d’enveloppe ou de puissance. À l’aide de simulations statistiques on compare le gain de diversité mesuré avec les valeurs simulées. / The testing of wireless devices is generally done using numerical simulations or channel sounders. Though a reverberation chamber does not reflect a real transmission environment, its properties can also be appropriately modifiedto emulate one. This emulation may be achieved thanks to various parameters. Our PhD thesis has been devoted toanalyze and implement several techniques to measure and control these parameters inside reverberation chambers.First we evaluate different K-factor estimators and their capabilities. We present the useful limits in which severalcomplex, phase and envelope K-factor estimators can be used. Then, we propose two new envelope-based estimatorsimproving the useful range of detectable values of K-factor. One of the possibilities to control a propagation channel inside areverberation chamber is to use absorbing materials. We present a method to estimate the average absorbing crosssection by using only one antenna. This is done with measurements of coherence bandwidth of the channel. Then,we extend our analysis to predict the average absorbing cross section when we know the physical dimensions of aparallelepiped absorber as well its electromagnetic properties. Next, we create a model of the reverberation chamberpropagation channel using the transient regime and steady state of the signal. With this model, depending on the availableinformation, we can extract the K-factor, the average absorbing cross section and different time spreads parameters (i.e., mean delay spread and the root mean square delay spread). We continue with two possible applications of the reverberation chamber. First, we evaluate the gain of an antenna from only the measurement of reflection coefficient. We extend our analysis to the evaluation of antenna pattern and its estimation errors. We also estimate the antenna mismatch and half power beamwidth. The second application deals with the evaluation of the diversity gain in reverberation chamber. We isolate the effects on the diversity gain due to different antenna efficiencies, stirred powers and K-factors. Then, we estimate a simple relation of the power correlation as a function of the complex correlation when the K-factors on different branches are not identical. We show that using an envelope/power correlation as a criterion to characterize the diversity may bias the conclusions without taking into account other parameters. Using statistical simulations we compare the measured diversity gain with the simulated values.

認購權證已在台灣發行與交易已接近七年的歷史，提供了更多套利、投機與避險交易的機會給市場參與者，也同時增加資本市場之完整性。而由於認購權證提供持有者在一段期間內依照特定價格購買特定數量標的股票之權利，投資人可以根據其意願與看法於到期日前來決定是否進行履約。而權證投資人購買權證之權利金即是包含內含價值與投資人願意支付的時間價值兩部分。時間價值的多寡反應出投資人對於未來權證履約價格是否可以無限增加的看法。而在其他條件不變之下，距到期時間越久之權證的價值應是越高。不過，是否時間越接近到期日時，投資人對於時間價值的看法就會呈現單純線性下降的狀態，還是另外有其他的資訊內涵會影響投資人對於價值的看法，即為本研究所欲探討之主題。 本研究針對台灣市場中個股型認購權證不同時點之時間價值變化程度，與可能影響時間價值變化的因素進行分析，其研究結果如下： 1.研究樣本並非完全符合越接近到期日時間價值減少的現象越明顯的狀態，顯示時間價值的變化隱含著會有其他之因素影響投資願意支付金額的多寡。且部分權證的確曾發生短期內時間價值大幅衰減的現象。 2.權證之價內外程度、距到期日之遠近、相對交易量的多寡與標的股票是否為電子業，對時間價值減少均有顯著的影響。另外，距到期日之天數、權證相對成交量、標的股票所屬產業與市場是否處於多頭與否均顯著影響短期內發生時間價值大幅衰退之現象。 3.本研究發現目前無法利用權證發行條件的差異，來判斷此權證是否會在存續期間當中發生時間價值急速衰退的現象。 / Warrants has been traded in Taiwan for seven years, and provides more opportunities for participants to arbitrage, hedge and speculate in capital market. Warrant gives holders the right to buy stocks at certain price during a period of time. The premium (price) to long warrants is contained intrinsic value and time value. Other things being equal, the longer the time to expiration day, the higher the value of warrants, since there is larger probability for investors to get more return. However, would any other terms expect time to expiration affect the variations of time value, or if we can find some variables could provide other content of information and result the change of time value. This is what the study focus on. Followings are the results of this study: 1. There are not all thetas of warrants in this sample decreasing simply by the time to expiration. It seems to be other variables would cause the change of theta. Besides, some warrants had serious time-decay in a short period of time. 2. Intrinsic value, time to expiration, trading volume, whether underlying stock in electronic industry or not and the market condition all have obvious effects on decrease of time value and serious time-decay. 3. It is still impossible to use issue information to identify if this warrant will have time-decay in its life.

Cette thèse est essentiellement composée de deux parties traitant des problèmes de Cauchy ou des problèmes périodiques. Dans la première partie, on étudie la stabilité de solutions régulières au voisinage d'états d'équilibre non constants pour un système d'Euler-Maxwell isentropique compressible bipolaire. Par des estimations d'énergie classiques et un argument de récurrence sur l'ordre des dérivées des solutions, on montre l'existence globale et l'unicité des solutions régulières du système lorsque les données initiales sont proches des états d'équilibre. On obtient aussi le comportement asymptotique des solutions quand le temps tend vers l'infini. Dans la deuxième partie, on considère la stabilité en temps long des solutions régulières de systèmes d'Euler-Maxwell et de Navier-Stokes-Maxwell compressibles dans le cas non isentropique lorsque les états d'équilibre sont constants. Grâce à des choix convenables de symétriseurs des systèmes et à des estimations d'énergie, on montre l'existence globale et l'unicité des solutions régulières des systèmes avec données initiales petites. De plus, par le principe de Duhamel et l'outil d'analyse de Fourier, on obtient des taux de décroissance des solutions quand le temps tend vers l'infini. / This thesis is essentially composed of two parts dealing with Cauchy problems and periodic problems. In the first part, we study the stability of smooth solutions near non constant equilibrium states for a two-fluid isentropic compressible Euler-Maxwell system.By classical energy estimates together with an induction argument on the order of the derivatives of solutions, we prove the existence and uniqueness of global solutions to the system when the given initial data are near the equilibrium states. We also obtain the asymptotic behavior of solutions when the time goes to infinity. In the second part, we consider the long time stability of the global smooth solutions for compressible Euler-Maxwell and Navier-Stokes-Maxwell systems in non isentropic case when the equilibrium solutions are constants. With the help of suitable choices of symmetrizers and energy estimates, we prove the existence and uniqueness of global solutions to the systems with given small initial data. Furthermore, using the Duhamel principle and the Fourier analysis tool, we obtain the decay rates of smooth solutions as the time goes to infinity.