Exact Analysis of TTL Cache Networks: The Case of Caching Policies driven by Stopping Times

TTL caching models have recently regained significant research interest, largely due to their ability to fit popular caching policies such as LRU. This paper advances the state-of-the-art analysis of TTL-based cache networks by developing two exact methods with orthogonal generality and computational complexity. The first method generalizes existing results for line networks under renewal requests to the broad class of caching policies whereby evictions are driven by stopping times. The obtained results are further generalized, using the second method, to feedforward networks with Markov arrival processes (MAP) requests. MAPs are particularly suitable for non-line networks because they are closed not only under superposition and splitting, as known, but also under input-output caching operations as proven herein for phase-type TTL distributions. The crucial benefit of the two closure properties is that they jointly enable the first exact analysis of feedforward networks of TTL caches in great generality

Approximation Schemes for a Unit-Demand Buyer with Independent Items via Symmetries

We consider a revenue-maximizing seller with $n$ items facing a single buyer. We introduce the notion of symmetric menu complexity of a mechanism, which counts the number of distinct options the buyer may purchase, up to permutations of the items. Our main result is that a mechanism of quasi-polynomial symmetric menu complexity suffices to guarantee a $(1-\varepsilon)$-approximation when the buyer is unit-demand over independent items, even when the value distribution is unbounded, and that this mechanism can be found in quasi-polynomial time. Our key technical result is a polynomial time, (symmetric) menu-complexity-preserving black-box reduction from achieving a $(1-\varepsilon)$-approximation for unbounded valuations that are subadditive over independent items to achieving a $(1-O(\varepsilon))$-approximation when the values are bounded (and still subadditive over independent items). We further apply this reduction to deduce approximation schemes for a suite of valuation classes beyond our main result. Finally, we show that selling separately (which has exponential menu complexity) can be approximated up to a $(1-\varepsilon)$ factor with a menu of efficient-linear $(f(\varepsilon) \cdot n)$ symmetric menu complexity.Comment: FOCS 201

Web based Information Sources with Reference to Forensic Science

Since from the dawn of human society information has a vital role in the development of the society in general. We find diversified explosion in all fields such as information explosion, population explosion, technological explosion, knowledge explosion. This led to the dynamism in creation, storage, distribution, delivery and demand for information. The “24X7, any time, any place information” paradigm of the networked environment is a challenge in the Information field. Internet, World Wide Web and Open Access have brought revolutionary changes in the field of Information. In this paper we try to bring forth various web based information sources in the field of Forensic Science

Fibroblast Growth Factor-9 Enhances M2 Macrophage Differentiation and Attenuates Adverse Cardiac Remodeling in the Infarcted Diabetic Heart

Inflammation has been implicated as a perpetrator of diabetes and its associated complications. Monocytes, key mediators of inflammation, differentiate into pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages upon infiltration of damaged tissue. However, the inflammatory cell types, which propagate diabetes progression and consequential adverse disorders, remain unclear. The current study was undertaken to assess monocyte infiltration and the role of fibroblast growth factor-9 (FGF-9) on monocyte to macrophage differentiation and cardioprotection in the diabetic infarcted heart. Db/db diabetic mice were assigned to sham, myocardial infarction (MI), and MI+FGF-9 groups. MI was induced by permanent coronary artery ligation and animals were subjected to 2D transthoracic echocardiography two weeks post-surgery. Immunohistochemical and immunoassay results from heart samples collected suggest significantly increased infiltration of monocytes (Mean +/- SEM; MI: 2.02% +/- 0.23% vs. Sham 0.75% +/- 0.07%; p \u3c 0.05) and associated pro-inflammatory cytokines (TNF-alpha, MCP-1, and IL-6), adverse cardiac remodeling (Mean +/- SEM; MI: 33% +/- 3.04% vs. Sham 2.2% +/- 0.33%; p \u3c 0.05), and left ventricular dysfunction (Mean +/- SEM; MI: 35.4% +/- 1.25% vs. Sham 49.19% +/- 1.07%; p \u3c 0.05) in the MI group. Importantly, treatment of diabetic infarcted myocardium with FGF-9 resulted in significantly decreased monocyte infiltration (Mean +/- SEM; MI+FGF-9: 1.39% +/- 0.1% vs. MI: 2.02% +/- 0.23%; p \u3c 0.05), increased M2 macrophage differentiation (Mean +/- SEM; MI+FGF-9: 4.82% +/- 0.86% vs. MI: 0.85% +/- 0.3%; p \u3c 0.05) and associated anti-inflammatory cytokines (IL-10 and IL-1RA), reduced adverse remodeling (Mean +/- SEM; MI+FGF-9: 11.59% +/- 1.2% vs. MI: 33% +/- 3.04%; p \u3c 0.05), and improved cardiac function (Fractional shortening, Mean +/- SEM; MI+FGF-9: 41.51% +/- 1.68% vs. MI: 35.4% +/- 1.25%; p \u3c 0.05). In conclusion, our data suggest FGF-9 possesses novel therapeutic potential in its ability to mediate monocyte to M2 differentiation and confer cardiac protection in the post-MI diabetic heart

Equity and Fairness of Bayesian Knowledge Tracing

We consider the equity and fairness of curricula derived from Knowledge Tracing models. We begin by defining a unifying notion of an equitable tutoring system as a system that achieves maximum possible knowledge in minimal time for each student interacting with it. Realizing perfect equity requires tutoring systems that can provide individualized curricula per student. In particular, we investigate the design of equitable tutoring systems that derive their curricula from Knowledge Tracing models. We first show that many existing models, including classical Bayesian Knowledge Tracing (BKT) and Deep Knowledge Tracing (DKT), and their derived curricula can fall short of achieving equitable tutoring. To overcome this issue, we then propose a novel model, Bayesian-Bayesian Knowledge Tracing (BBKT), that naturally enables online individualization and, thereby, more equitable tutoring. We demonstrate that curricula derived from our model are more effective and equitable than those derived from classical BKT models. Furthermore, we highlight that improving models with a focus on the fairness of next-step predictions might be insufficient to develop equitable tutoring systems

Darning Needle Impacted in the Male Urethra

Foreign bodies of varied nature have been introduced into the urethra to achieve sexual stimulation. We report the case of a long (9.5 cm) darning needle impacted in the urethra of a male patient following urethral masturbation. After a failed trial at endoscopic extraction the needle had to be removed via open surgery. Follow-up was uneventful