803 research outputs found
Optimal sequential fingerprinting: Wald vs. Tardos
We study sequential collusion-resistant fingerprinting, where the
fingerprinting code is generated in advance but accusations may be made between
rounds, and show that in this setting both the dynamic Tardos scheme and
schemes building upon Wald's sequential probability ratio test (SPRT) are
asymptotically optimal. We further compare these two approaches to sequential
fingerprinting, highlighting differences between the two schemes. Based on
these differences, we argue that Wald's scheme should in general be preferred
over the dynamic Tardos scheme, even though both schemes have their merits. As
a side result, we derive an optimal sequential group testing method for the
classical model, which can easily be generalized to different group testing
models.Comment: 12 pages, 10 figure
The holey grail A special score function for non-binary traitor tracing
We study collusion-resistant traitor tracing in the simple decoder approach, i.e. assignment of scores for each user separately.
We introduce a new score function for non-binary bias-based traitor tracing. It has three special properties that have long been sought after:
(i) The expected score of an innocent user is zero in each content position.
(ii) The variance of an innocent user\u27s score is~1 in each content position.
(iii) The expectation of the coalition\u27s score does not depend on the
collusion strategy.
We also find a continuous bias distribution that optimizes the asymptotic (large coalition) performance.
In the case of a binary alphabet our scheme reduces exactly to the
symmetrized Tardos traitor tracing system.
Unfortunately, the asymptotic fingerprinting rate
of our new scheme decreases with growing alphabet size.
We regret to inform you that this grail has holes
High Multiplicity Scheduling with Switching Costs for few Products
We study a variant of the single machine capacitated lot-sizing problem with
sequence-dependent setup costs and product-dependent inventory costs. We are
given a single machine and a set of products associated with a constant demand
rate, maximum loading rate and holding costs per time unit. Switching
production from one product to another incurs sequencing costs based on the two
products. In this work, we show that by considering the high multiplicity
setting and switching costs, even trivial cases of the corresponding "normal"
counterparts become non-trivial in terms of size and complexity. We present
solutions for one and two products.Comment: 10 pages (4 appendix), to be published in Operations Research
Proceedings 201
A capacity-achieving simple decoder for bias-based traitor tracing schemes
We investigate alternative suspicion functions for bias-based traitor tracing schemes, and present a practical construction of a simple decoder that attains capacity in the limit of large coalition size c. We derive optimal suspicion functions in both the Restricted- Digit Model and the Combined-Digit Model. These functions depend on information that is usually not available to the tracer – the attack strategy or the tallies of the symbols received by the colluders. We discuss how such results can be used in realistic contexts. We study several combinations of coalition attack strategy versus suspicion function optimized against some attack (another attack or the same). In many of these combinations the usual codelength scaling changes to a lower power of , e.g., . We find that the interleaving strategy is an especially powerful attack. The suspicion function tailored against interleaving is the key ingredient of the capacity-achieving construction
Cyclic Lot-Sizing Problems with Sequencing Costs
We study a single machine lot-sizing problem, where n types of products need to be scheduled on the machine. Each product is associated with a constant demand rate, maximum production rate and inventory costs per time unit. Every time when the machine switches production between products, sequencing costs are incurred. These sequencing costs depend both on the product the machine just produced and the product the machine is about to produce. The goal is to find a cyclic schedule minimizing total average costs, subject to the condition that all demands are satisfied. We establish the complexity of the problem and we prove a number of structural properties largely characterizing optimal solutions. Moreover, we present two algorithms approximating the optimal schedules by augmenting the problem input. Due to the high multiplicity setting, even trivial cases of the corresponding conventional counterparts become highly non-trivial with respect to the output sizes and computational complexity, even without sequencing costs. In particular, the length of an optimal solution can be exponential in the input size of the problem. Nevertheless, our approximation algorithms produce schedules of a polynomial length and with a good quality compared to the optimal schedules of exponential length
The Holey Grail: A special score function for non-binary traitor tracing
We study collusion-resistant traitor tracing in the simple decoder approach, i.e. assignment of scores for each user separately.
We introduce a new score function for non-binary bias-based traitor tracing. It has three special properties that have long been sought after:
(i) The expected score of an innocent user is zero in each content position.
(ii) The variance of an innocent user\u27s score is~1 in each content position.
(iii) The expectation of the coalition\u27s score does not depend on the
collusion strategy.
We also find a continuous bias distribution that optimizes the asymptotic (large coalition) performance.
In the case of a binary alphabet our scheme reduces exactly to the
symmetrized Tardos traitor tracing system.
Unfortunately, the asymptotic fingerprinting rate
of our new scheme decreases with growing alphabet size.
We regret to inform you that this grail has holes
Curcumin as Treatment for Bladder Cancer : A Preclinical Study of Cyclodextrin-Curcumin Complex and BCG as Intravesical Treatment in an Orthotopic Bladder Cancer Rat Model
Objective. To evaluate the antitumor effect of cyclodextrin-curcumin complex (CDC) on human and rat urothelial carcinoma cells in vitro and to evaluate the effect of intravesical instillations of CDC, BCG, and the combination in vivo in the AY-F344 orthotopic bladder cancer rat model. Curcumin has anticarcinogenic activity on urothelial carcinoma and is therefore under investigation for the treatment of non-muscle invasive bladder cancer. Curcumin and BCG share immunomodulating pathways against urothelial carcinoma. Methods. Curcumin was complexed with cyclodextrin to improve solubility. Four human urothelial carcinoma cell lines and the AY-27 rat cell line were exposed to various concentrations of CDC in vitro. For the in vivo experiment, the AY-27 orthotopic bladder cancer F344 rat model was used. Rats were treated with consecutive intravesical instillations of CDC, BCG, the combination of CDC+BCG, or NaCl as control. Results. CDC showed a dose-dependent antiproliferative effect on all human urothelial carcinoma cell lines tested and the rat AY-27 urothelial carcinoma cell line. Moreover, intravesical treatment with CDC and CDC+BCG results in a lower percentage of tumors (60% and 68%, respectively) compared to BCG (75%) or control (85%). This difference with placebo was not statistically significant (p=0.078 and 0.199, respectively). However, tumors present in the placebo and BCG-treated rats were generally of higher stage. Conclusions. Cyclodextrin-curcumin complex showed an antiproliferative effect on human and rat urothelial carcinoma cell lines in vitro. In the aggressive orthotopic bladder cancer rat model, we observed a promising effect of CDC treatment and CDC in combination with BCG.Peer reviewe
Personalized Nutrition in Patients with Type 2 Diabetes and Chronic Kidney Disease:The Two-Edged Sword of Dietary Protein Intake
In type 2 diabetes (T2D), there is a general and strong focus on carbohydrate restriction. However, this may have unwarranted consequences for those with concomitant chronic kidney disease (CKD) since decreasing intake of carbohydrates implies a higher proportion of dietary protein, which is of critical debate in patients with CKD due to its ambiguous implications in maintaining either kidney function or nutritional status. We evaluated adherence to the protein recommendations, taking into account the nutritional status of patients with T2D with or without CKD. Patients were divided in three groups according to their estimated Glomerular Filtration Rate (eGFR): mild to no CKD (eGFR > 60 mL/min/1.73 m(2)), moderate CKD (eGFR 30–60 mL/min/1.73 m(2)), or advanced CKD (eGFR 1.3 g/kg/day, and 60% of the patients with advanced CKD consumed > 1.0 g/kg/day. In addition, patients with moderate- or advanced CKD tend to have a lower muscle mass, normalized by height, compared to patients with mild to no CKD (p < 0.001), while body mass index was not significantly different between patients with or without CKD (p = 0.44). We found that although dietary protein restriction has not been indicated in either of the CKD stages, approximately 10% had a dietary protein intake < 0.8 g/kg/day, with accompanying risks of malnourishment and sarcopenia. Our main advice is to maintain a dietary protein intake of at least 0.8 g/kg/day in order to prevent patients from becoming malnourished and sarcopenic
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