46,429 research outputs found
On the fundamental theorem of asset pricing: random constraints and bang-bang no-arbitrage criteria
No full textThe paper generalizes and refines the Fundamental Theorem of Asset Pricing of Dalang, Morton and Willinger in the following two respects: (a) the result is extended to a model with portfolio constraints; (b) versions of the no-arbitrage criterion based on the bang-bang principle in control theory are developed.no arbitrage criteria, portfolio constraints, supermartingale measures, bang-bang control
Statistical analysis of first-order bang-bang phase-locked loops using sign-dependent random-walk theory
No full textBang-bang phase-locked loops (BBPLLs) are inherently nonlinear due to the hard nonlinearity introduced by the binary phase detector (BPD). This paper provides an exact
statistical analysis of the steady-state timing jitter in a first order BBPLL when the reference clock is subject to accumulative
jitter. By elaborating on the analogy of viewing a first-order BBPLL as a single-integration delta modulator (DM) in the
phase domain, we are able to relate hunting jitter and slew-rate limiting in a BBPLL to granular noise and slope overload in a DM. The stochastic timing-jitter behavior is modeled as a sign-dependent random walk, for which we obtain the asymptotic characteristic function and analytical expressions for the first four cumulants. These expressions are applied to the BBPLL to
statistically analyze the static timing offset and the RMS timing jitter, including the effect of a frequency offset. The analysis shows that the RMS timing jitter is constant for small RMS clock jitter and grows quadratically with large RMS clock jitter, and that there exists an optimal bang-bang phase step for minimum RMS timing jitter. Computing the kurtosis reveals the effect of the BPD nonlinearity: the timing jitter is largely non-Gaussian.Science Foundation Irelandke, ab, li - TS 17.04.1
Binary phase detector gain in bang-bang phase-locked loops with DCO jitter
No full textBang-bang phase-locked loops (BBPLLs) are hard nonlinear systems due to the nonlinearity introduced by the binary phase detector (BPD). In the presence of jitter, the nonlinear loop is typically analyzed by linearizing the BPD and applying linear transfer functions in the analysis. In contrast to a linear PD, the linearized gain of a BPD depends on the rms jitter and the type of jitter (either non-accumulative
or accumulative). Previous works considered the case of nonaccumulative reference clock jitter and showed that the BPD gain is inversely proportional to the rms jitter when the latter is small or large. In this brief we consider the case of accumulative
DCO jitter and derive an asymptotic closed-form expression for the BPD gain which becomes exact in the limit of small and large
jitter. Contrary to the reference clock jitter case, the BPD gain is constant for small DCO jitter and is inversely proportional to the square of jitter for large DCO jitter; in the latter case, the
timing jitter has a normal-Laplace distribution.Science Foundation Irelandti, ke, ab, li - TS 10.04.1
Output-jitter performance of second-order digital bang-bang phase-locked loops with nonaccumulative reference clock jitter
No full textBang-bang phase-locked loops (BBPLLs) are inherently nonlinear systems due to the binary phase detector (BPD). While they are typically used for clock and data recovery, the ongoing trend toward digital loop implementations has resulted in several digital BBPLLs (DBBPLLs) suitable for frequency synthesis. This brief investigates the effect of nonaccumulative reference clock jitter (due to white phase noise) in second-order DBBPLLs, comparing the output jitter with that of first-order DBBPLLs. For small clock jitter, the nonlinear loop behavior is modeled as a two-dimensional Markov chain, and the output jitter is smaller than but close to that of a first order loop. For large clock jitter, the BPD nonlinearity is linearized, and the output jitter is larger than that of a first order loop; it is proportional to clock jitter and inversely proportional to the square root of the stability factor—the ratio of the proportional path gain to the integral-path gain of the digital loop filter.Science Foundation Irelandti, ke, ab, li - TS 18.04.1
The Japanese Big Bang: the effects of "free, fair and global"
No full textThe Japanese “Big Bang” financial deregulations started in 1996. The objective was to make the Japanese banking sector more “free, fair and global”, spurring competition and resulting in a more profitable and efficient financial sector. The Big Bang brought about a massive consolidation of Japan’s already relatively concentrated banking sector. Japan’s “Top 20” banks have now merged to just three financial conglomerates that are among the largest in the world. Is this a sign of the success? Focusing on the Big Bang’s stated objectives of promoting profitability and efficiency, this study examines the Japanese “Big Bang” deregulation from its start in 1996 to completion in 2001, and the following eight years. On profitability, we find that the banking sector as a whole did not become more profitable than the pre-deregulation period. Rather, we see a steady decline in profitability. In addition, the main targets of the deregulation (and the most active in mergers and acquisitions activity during our sample period), the city, trust and long-term credit banks, actually exhibit lower profitability measured in ROA and ROE than the smaller regional banks. The “Big Bang” did not succeed in promoting a more profitable banking sector. We next turn to efficiency. We find that in terms of cost reduction, the banking sector did become more efficient after the Big Bang deregulation. However, the real bottom line of performance, profit efficiency, declined. In addition, we again see a significant difference between the big city, trust long-term credit banks and the smaller regional banks. The biggest banks are statistically significantly less profit efficient, despite their higher cost efficiency. Thus, on the whole, the Japanese “Big Bang” financial deregulation was not successful in achieving its stated objectives. Both profitability and efficiency declines on the whole, and the main targets of the deregulation, the big city, trust and long-term credit banks, exhibit statistically significantly lower profitability and efficiency than their smaller counterparts.deregulation; profitability; efficiency
A Reassessment of Japanfs Big Bang Financial Regulatory Reform
No full textThis paper reassesses the results of Japanfs financial deregulation over the last two decades. Japanfs Big Bang sought to transform a highly regulated bank-centered financial system to a transparent, market-centered financial system to revitalize Japanfs economy and aging society. Prior assessments generally view this reform effort as a failure due to Japanfs low economic growth rate. This paper finds, contrary to conventional wisdom, that government-led deregulatory and administrative reform was largely successful in removing legal and administrative obstacles to the development of a market-centered financial system. However, the persistence of past practices by market participants and strong headwinds such as low macroeconomic growth and poor financial market performance prevented achievement of the Big Bangf s ambitious goals. This illustrates both the limits of what can be accomplished through deregulation of financial markets and the problem inherent in using a results-oriented standard in evaluating Japanfs reform efforts.Big Bang, Financial Deregulation, Financial Reform, Corporate Bond Market, Venture Capital, Financial Center
Vitamin A: a key coordinator of host-microbe interactions in the intestine
No full textThe human intestine is home to a dense community of microbiota that plays a key role in human health and disease. Nutrients are essential regulators of both host and microbial physiology and function as key coordinators of host-microbe interactions. Therefore, understanding the specific roles and underlying mechanisms of each nutrient in regulating the host-microbe interactions will be essential in developing new strategies for improving human health through microbiota and nutrient intervention. This review will give a basic overview of the role of vitamin A, an essential micronutrient, on human health, and highlight recent findings on the mechanisms by which it regulates the host-microbe interactions. [BMB Reports 2023; 56(3): 133-139].N
Investigation of first-order digital bang-bang phase-locked loops with reference clock jitter
No full textPaper presented at the Nordic microelectronics conference (NORCHIP), Tallinn, Estonia, 17-18 November, 2008Bang-bang phase-locked loops (BBPLLs) are a class of PLLs with a binary-quantized phase detector (BPD). They are widely used in clock and data recovery circuits and have
recently been implemented as digital BBPLLs for high-bandwidth synthesis. This paper investigates a first-order digital BBPLL
with reference clock jitter. We derive the Chapman-Kolmogorov equation which statistically characterizes the timing jitter process. The numerical solution of this equation allows us to compute the timing jitter probability density function (PDF) in steadystate and to examine the effect of varying loop detuning and
RMS reference clock jitter on the timing offset, the RMS timing jitter and the mean number of steps to slip a cycle. The analysis
shows that the steady-state PDF is Gaussian-like only for a small range of RMS clock jitter values, which leads to a new curve for
the BPD gain as a function of jitter.Science Foundation Irelandke, ab, co, li - TS 10.04.1
Adaptation Strategies to Address Coastal Erosion/Flooding: A Case Study of the Communities in Bang Khun Thian District, Bangkok, Thailand
No full textCoastal erosion is a serious problem in Thailand nowadays. The impacts of coastal erosion on the flat and low-lying Gulf area are expected to be high. The sediment supply to the coasts in the Upper Gulf of Thailand, including Bang Khun Thian district in Bangkok, has been decreasing because of dam constructions, combined with relative sealevel rise (subsidence) due to excessive ground water extraction. The loss of coastal land significantly affects the livelihood of the local people. At present, the Bangkok boundary mark at Bang Khun Thian district is already submerged. The mark was made taller by the Bangkok Metropolitan Administration afterwards. Over the past 28 years, coastal erosion has decreased the shoreline by 4-800 meters, at the rate of 20-25 meters per year. Two villages in Bang Khun Thian, whose major economic activities are shrimp and blood cockle farming, have been affected by coastal erosion. This study aims to determine households' adaptation strategies to address coastal erosion/flooding. It entailed a site visit, discussion with the local people, literature review, and a household survey. The results indicate that households have individually applied three types of autonomous adaptation strategies, which are (1) protection (e.g., stone breakwaters, bamboo revetments, and dike heightening), (2) retreat, and (3) accommodation. Of these, protection is the most popular. Each household had applied more than one adaptation option. The annual adaptation cost is approximately US$3,130 per household, which is equal to 23 percent of the average household income. The average inundated area is about 0.9 hectare per household or 8 percent of the household aquaculture area. The existing government's assistance for coastal erosion/flooding is in the form of stone breakwater, which is ineffective, and flooding compensation. This study showed that individual adaptation strategies, without any collective adaptation strategies, may not be effective solutions due to the occurrence of negative externalities if the neighbors do not apply/maintain their own protection structures. Secondly, due to low educational attainment and lack of other knowledge and skills, farmers could not shift to other occupations. This lack of livelihood choices explains why farmers are willing to pay highly to apply/maintain their protection structures. Lastly, for the protection structure to be effective in protecting the shore, it should be planned for the whole Upper Gulf of Thailand. Thus, the cooperation of the national government, local governments, and the public is necessary to address the problem of coastal erosion/flooding.coastal erosion, Thailand
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