Bypassing the Monster: A Faster and Simpler Optimal Algorithm for Contextual Bandits Under Realizability

We consider the general (stochastic) contextual bandit problem under the realizability assumption, that is, the expected reward, as a function of contexts and actions, belongs to a general function class [Formula: see text]. We design a fast and simple algorithm that achieves the statistically optimal regret with only [Formula: see text] calls to an offline regression oracle across all T rounds. The number of oracle calls can be further reduced to [Formula: see text] if T is known in advance. Our results provide the first universal and optimal reduction from contextual bandits to offline regression, solving an important open problem in the contextual bandit literature. A direct consequence of our results is that any advances in offline regression immediately translate to contextual bandits, statistically and computationally. This leads to faster algorithms and improved regret guarantees for broader classes of contextual bandit problems.

Optimal Reduction in the Number of Test Vectors for Soft Processor Cores Implemented in FPGA

Testing FPGA-based soft processor cores requires a completely different methodology in comparison to standard processors. The stuck-at fault model is insufficient, as the logic is implemented by lookup tables (LUTs) in FPGA, and this SRAM-based LUT memory is vulnerable to single-event upset (SEU) mainly caused by cosmic radiations. Consequently, in this paper, we used combined SEU-induced and stuck-at fault models to simulate every possible fault. The test program written in an assembler was based on the bijective property. Furthermore, the fault detection matrix was determined, and this matrix describes the detectability of every fault by every test vector. The major novelty of this paper is the optimal reduction in the number of required test vectors in such a way that fault coverage is not reduced. Furthermore, this paper also studied the optimal selection of test vectors when only 95% maximal fault coverage is acceptable; in such a case, only three test vectors are required. Further, local and global test vector selection is also described.

Optimal Reduction of Number of Test Vectors for Soft Processor Cores Implemented in FPGA

This paper describes a new optimization methodology of testing vector sets reduction for testing of soft-processor cores and their individual blocks. The deterministic test vectors both for whole core and its individual blocks are investigated that significantly reduce the testing time and amount of test data that needs to be stored on the tester memory. The processor executes an assembler program which together with determined testing vectors ex-ercise its functionality. The new BIST methodology applicable at industrial testing of processor cores, diagnostics and dynamic reconfiguration of FPGA is proposed. This novel methodology combined with dynamic reconfiguration of FPGAs can be profitable applied for missions-critical i.e. FPGAs operate in space, or other difficult condition where are explore on radiation. Experimental results demonstrate that the proposed approach reduces many times testing time.

Electrolytic Reduction of Titanium Dioxide in Molten LiCl–Li2O

The electrolytic reduction of TiO2 in LiCl–Li2O (1 wt.%) at 650 °C was investigated under a series of cathodic reduction potentials and applied charges to provide a mechanistic understanding of the electrochemical characteristics of the system. The optimal cathodic reduction potential was determined as being −0.3 V vs. Li/Li+. Li2TiO3 and LiTiO2 were structurally identified as intermediate and partial reduction products of the TiO2 electrolytic reduction. The reduction of LiTiO2 was extremely slow and reversible due to its high stability and the detrimental effect of Li2O accumulation within the solid particles. The most reduced product obtained in this study was LiTiO2, which was achieved when using 150% of the theoretical charge under the optimal reduction potential. The highest reduction extent obtained in this study was 25%. Based on theoretical DFT modeling, a detailed multistep reduction mechanism and scheme were proposed for TiO2 electrolytic reduction in LiCl–Li2O (1 wt.%) at 650 °C.

Recovery of zinc from zinc oxide dust containing multiple metal elements by carbothermal reduction

A carbothermal reduction process simulating EAF process is used to handle the zinc oxide dust, and the zinc in the dust can be extracted and recovered efficiently. The crude zinc and lead-tin alloy were obtained finally. The effects of temperature, holding time, and reductant dosage on zincvolatilization rate were investigated, and the ?Pelletizing -Calcination-Carbothermic reduction? experiment was conducted. The resultsfound the optimal reduction condition was as follows: the temperature of 1300?C, reductant dosage of 14.04% and holding time of 120 min. After the calcination at 900?C for 120 min, the removal rates of fluorine, chlorine and sulfur in the dust were 98.18%, 96.38% and 28.58% respectively, and the volatilization rate of zinc was 99.83% in reduction process. The zinc content of the crude zinc was 68.48%.

Perbandingan Kemampuan Aerasi Sembur (Spray) dengan Metode Adsorpsi Menggunakan Adsorben Serbuk Kulit Buah Kakao untuk Menurunkan Kadar Besi dan Mangan Pada Air Sumur Gali

Research on the use of the spray aeration method with adsorption of cocoa rind powder to reduce iron and manganese levels in dug well water has been carried out. This study aims to make comparisons from two methods to reduce iron and manganese in dug well water. The parameters optimized in this study are the aeration time and the variation of the addition of the adsorbent mass and the adsorption time. Based on the research results, the spray aeration time for 2 hours gave the optimal percentage reduction for Fe3+ and Mn4+ metal ions, namely 98.68% and 94.22%. Meanwhile, for adsorption using cocoa pod husk powder, the optimal reduction occurred in the adsorbent mass of 0.2 grams and the adsorption time of 60 minutes for iron and manganese 96.36% and 95.15%, respectively.

Thermodynamic and Experimental Study on Efficient Extraction of Valuable Metals from Polymetallic Nodules

Polymetallic nodules are promising resources for the extraction of valuable metals such as copper, nickel, and cobalt, as well as manganese alloys. To achieve efficient extraction of useful metals from the emerging resource, high-temperature carbothermic reduction of nodules was investigated by optimizing the reductant addition, slag and alloy systems. Thermochemical software FactSage was used to predict the liquidus temperature of the slag system, which is not sensitive to FeO, CaO and Al2O3, but decreases significantly with decreasing MnO/SiO2 mass ratio. The experiments were designed to reduce the oxides of Cu, Co and Ni completely, and reduce FeOx partially depending on the amount of graphite addition while leaving the residual slag for further processing into ferromanganese and/or silicomanganese alloys. Co, Cu and Ni concentrations in the alloy decreased with increasing graphite addition. The optimal reduction condition was reached by adding 4 wt% graphite at the MnO/SiO2 mass ratio of 1.6 in slag. The most effective metal-slag separation was achieved at 1350 °C, which enables the smelting reduction to be carried out in various furnaces.