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In this paper we address a solution for detecting and tolerating one of the most typical concurrency bugs: atomicity violations. More specifically, we address High-Level Atomicity Violations (HLAV). High-level atomicity violations result from the misspecification of the scope of an atomic block, by splitting it in two or more atomic blocks which may be interleaved with other atomic blocks. Figure 1 shows an example of this type of atomicity violation. The intuitive idea behind HLAV is that if two shared data items (e.g., memory locations) were both accessed inside an atomic block, they are interrelated and probably the programmer intention is that there shall be no interleavings between these two accesses. Therefore, if (in the same program) this two addresses are accessed separately in different atomic blocks, an unfortunate interleaving may cause an atomicity violation.

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A novel immobilized Ca0.6Ho0.4MnO3 photocatalyst has been developed with high photocatalytic activity for Rhodamine 6G (Rh6G) photodegradation under visible light irradiation. The nanocrystalline Ca0.6Ho0.4MnO3 films were successfully deposited by RF-magnetron sputtering on unheated quartz glass substrates using Ca0.6Ho0.4MnO3 powder as sputtering target and its photocatalytic functionalities have been explored. The visible-light-responsive photocatalytic activity of Ca0.6Ho0.4MnO3 films was evaluated by the photodegradation of Rh6G aqueous solutions under visible light irradiation. The reusability of Ca0.6Ho0.4MnO3 films on fresh dye samples was studied, showing an efficient reuse, without decreasing the photocatalytic decolorization efficiency. Furthermore, X-ray diffraction of the reused films did not reveal additional phases indicating high photochemical stability of the films even after reusing them in successive runs. The photocatalytic efficiency of the nanocrystalline Ca0.6Ho0.4MnO3 films was further compared with TiO2 films also produced by sputtering and the results revealed a significant improvement in photocatalytic activity over TiO2 under visible light irradiation. Almost complete photodecolorization of a 5 ppm Rh6G solution was achieved in 4 h, while only 64% of dye degradation was observed in TiO2 photoassisted process. This work provides a feasible route to fabricate high-performance immobilized ABO3-based nanomaterials, and the finding opens up a new venue for designing visible light sensitive ternary compounds for photocatalytical applications. A novel immobilized Ca0.6Ho0.4MnO3 photocatalyst has been developed with high photocatalytic activity for Rhodamine 6G (Rh6G) photodegradation under visible light irradiation. The nanocrystalline Ca0.6Ho0.4MnO3 films were successfully deposited by RF-magnetron sputtering on unheated quartz glass substrates using Ca0.6Ho0.4MnO3 powder as sputtering target and its photocatalytic functionalities have been explored. The visible-light-responsive photocatalytic activity of Ca0.6Ho0.4MnO3 films was evaluated by the photodegradation of Rh6G aqueous solutions under visible light irradiation. The reusability of Ca0.6Ho0.4MnO3 films on fresh dye samples was studied, showing an efficient reuse, without decreasing the photocatalytic decolorization efficiency. Furthermore, X-ray diffraction of the reused films did not reveal additional phases indicating high photochemical stability of the films even after reusing them in successive runs. The photocatalytic efficiency of the nanocrystalline Ca0.6Ho0.4MnO3 films was further compared with TiO2 films also produced by sputtering and the results revealed a significant improvement in photocatalytic activity over TiO2 under visible light irradiation. Almost complete photodecolorization of a 5 ppm Rh6G solution was achieved in 4 h, while only 64% of dye degradation was observed in TiO2 photoassisted process. This work provides a feasible route to fabricate high-performance immobilized ABO3-based nanomaterials, and the finding opens up a new venue for designing visible light sensitive ternary compounds for photocatalytical applications.

This paper presents a micro power light energy harvesting system for indoor environments. Light energy is collected by amorphous silicon photovoltaic (a-Si:H PV) cells, processed by a switched capacitor (SC) voltage doubler circuit with maximum power point tracking (MPPT), and finally stored in a large capacitor. The MPPT fractional open circuit voltage (V-OC) technique is implemented by an asynchronous state machine (ASM) that creates and dynamically adjusts the clock frequency of the step-up SC circuit, matching the input impedance of the SC circuit to the maximum power point condition of the PV cells. The ASM has a separate local power supply to make it robust against load variations. In order to reduce the area occupied by the SC circuit, while maintaining an acceptable efficiency value, the SC circuit uses MOSFET capacitors with a charge sharing scheme for the bottom plate parasitic capacitors. The circuit occupies an area of 0.31 mm(2) in a 130 nm CMOS technology. The system was designed in order to work under realistic indoor light intensities. Experimental results show that the proposed system, using PV cells with an area of 14 cm(2), is capable of starting-up from a 0 V condition, with an irradiance of only 0.32 W/m(2). After starting-up, the system requires an irradiance of only 0.18 W/m(2) (18 mu W/cm(2)) to remain operating. The ASM circuit can operate correctly using a local power supply voltage of 453 mV, dissipating only 0.085 mu W. These values are, to the best of the authors' knowledge, the lowest reported in the literature. The maximum efficiency of the SC converter is 70.3 % for an input power of 48 mu W, which is comparable with reported values from circuits operating at similar power levels.

This paper presents a micro power light energy harvesting system for indoor environments. Light energy is collected by amorphous silicon photovoltaic (a-Si:H PV) cells, processed by a switched capacitor (SC) voltage doubler circuit with maximum power point tracking (MPPT), and finally stored in a large capacitor. The MPPT fractional open circuit voltage (V-OC) technique is implemented by an asynchronous state machine (ASM) that creates and dynamically adjusts the clock frequency of the step-up SC circuit, matching the input impedance of the SC circuit to the maximum power point condition of the PV cells. The ASM has a separate local power supply to make it robust against load variations. In order to reduce the area occupied by the SC circuit, while maintaining an acceptable efficiency value, the SC circuit uses MOSFET capacitors with a charge sharing scheme for the bottom plate parasitic capacitors. The circuit occupies an area of 0.31 mm(2) in a 130 nm CMOS technology. The system was designed in order to work under realistic indoor light intensities. Experimental results show that the proposed system, using PV cells with an area of 14 cm(2), is capable of starting-up from a 0 V condition, with an irradiance of only 0.32 W/m(2). After starting-up, the system requires an irradiance of only 0.18 W/m(2) (18 mu W/cm(2)) to remain operating. The ASM circuit can operate correctly using a local power supply voltage of 453 mV, dissipating only 0.085 mu W. These values are, to the best of the authors' knowledge, the lowest reported in the literature. The maximum efficiency of the SC converter is 70.3 % for an input power of 48 mu W, which is comparable with reported values from circuits operating at similar power levels.