A resource broker with an efficient network information model on grid environments

This paper describes a resource broker whose main function is to match available resources to user needs. The resource broker provides a uniform interface for accessing available and appropriate resources via user credentials. We also focus on providing approximate measurement models for network-related information using NWS for future scheduling and benchmarking. We first propose a network measurement model for gathering network-related information (including bandwidth, latency, forecasting, error rates, etc.) without generating excessive system overhead. Second, we constructed a grid platform using Globus Toolkit that integrates the resources of five schools in Taichung integrated grid environment resources (TIGER). The resource broker runs on top of TIGER. Therefore, it provides security and current information about available resources and serves as a link to the diverse systems available in the Grid.

Optimal design of CMOS pseudoactive pixel sensor (PAPS) structure for low-dark-current and large-array-size imager applications

In this paper, a pixel structure called the optimal pseudoactive pixel sensor (OPAPS) is proposed and analyzed for the applications of CMOS imagers. The shared zero-biased-buffer in the pixel is used to suppress both dark current of photodiode and leakage current of pixel switches by keeping both biases of photodiode and parasitic pn junctions in the pixel bus at zero voltage or near zero voltage. The factor of photocurrent-to-dark-current ratio per pixel area (PDRPA) is defined to characterize the performance of the OPAPS structure. It is found that a zero-biased-buffer shared by four pixels can achieve the highest PDRPA. In addition, the column sampling circuits and output correlated double sampling circuits are also used to suppress fixed-pattern noise, clock feedthrough noise, and channel charge injection. An experimental chip of the proposed OPAPS CMOS imager with the format of 352/spl times/288 (CIF) has been designed and fabricated by using 0.25-/spl mu/m single-poly-five-level-metal (1P5M) N-well CMOS process. In the fabricated CMOS imager, one shared zero-biased-buffer is used for four pixels where the PDRPA is equal to 47.29 /spl mu/m/sup -2/. The fabricated OPAPS CMOS imager has a pixel size of 8.2/spl times/.2 /spl mu/m, fill factor of 42%, and chip size of 3630/spl times/3390 /spl mu/m. Moreover, the measured maximum frame rate is 30 frames/s and the dark current is 82 pA/cm/sup 2/. Additionally, the measured optical dynamic range is 65 dB. It is found that the proposed OPAPS structure has lower dark current and higher optical dynamic range as compared with the active pixel sensor (APS) and the conventional passive pixel sensor (PPS). Thus, the proposed OPAPS structure has high potential for the applications of high-quality and large-array-size CMOS imagers.     

A fault-tolerant wormhole routing scheme for torus networks with nonconvex faults

In this paper, we present a fault-tolerant routing algorithm for torus networks by using only 4 virtual channels. The proposed algorithm is based on the solid fault model, which includes rectangular faults and many practical nonconvex faults. Previous works need at least 6 virtual channels to achieve the same fault-tolerant ability.     

Boundary effects on the optical properties of InGaN multiple quantum wells

We examine the issues of spontaneous and piezoelectric polarization discontinuity on the optical properties of 3.0-nm-thick indium gallium nitride (InGaN) multiple quantum wells (MQWs). A quench of band-edge emission from the cap GaN layer is observed when the photoexcitation source is changed from a 355- to a 248-nm laser. The interband transitions from the InGaN wells exhibit a linear dependence on the 1) spectral blue shift of /spl sim/8.5/spl times/10/sup -18/ meV /spl middot/ cm/sup 3/ and 2) change of the internal field of /spl sim/3/spl times/10/sup -14/ meV /spl middot/ cm/sup 2/ with the injected carrier density up to N/sub inj//spl sim/10/sup 19/ cm/sup -3/ at 77 K. These observations are attributed to the redistribution of photogenerated carriers in the InGaN wells due to the polarization discontinuity at the QW interface and the surface band bending effect. By incorporating an additional boundary condition of surface Fermi-level pinning into the Poisson equation and the band-structure analysis, it is shown the emission from the InGaN-GaN MQWs is dominant by the recombination between the high-lying subbands and the screening of internal field effects.     

Design, optimization, and performance analysis of new photodiode structures for CMOS active-pixel-sensor (APS) imager applications

The dark current in the active-pixel-sensor (APS) cell of a CMOS imager is known to be mainly generated in the regions of bird's beak after the local oxidation of silicon process as well as the surface damage caused by the implantation of high doping concentration. Furthermore, shallow and deep pn-junctions can improve the photo-sensitivity for light of short and long wavelengths, respectively. In this paper, two new photodiode structures using p-substrate and lightly-doped sensor implant SN- as pn-junction photodiode with the regions of bird's beak embraced by SN- and p-field implants, respectively, are proposed and analyzed to reduce dark current and enhance the overall spectral response. 5 /spl mu/m/spl times/5 /spl mu/m APS cells fabricated in a 0.35-/spl mu/m single-poly-triple-metal (1P3M) 3.3-V CMOS process are designed by using the proposed photodiode structures. As shown from the experimental results, the two proposed photodiode structures of 5 /spl mu/m/spl times/5 /spl mu/m APS cells have lower dark currents of 30.6 mV/s and 35.2 mV/s at the reverse-biased voltage of 2 V and higher spectral response, as compared to the conventional structure and other photodiode structures. Thus, the two proposed new photodiode structures can be applied to CMOS imager systems with small pixel size, high resolution, and high quality.     

Engineered Immature Testicular Tissue by Electrospun Mats for Prepubertal Fertility Preservation in a Bioluminescence Imaging Transgenic Mouse Model

Prepubertal boys with cancer may suffer from reduced fertility and maturity following gonadotoxic chemoradiotherapy. Thus, a viable method of immature testicular tissue (ITT) preservation is required in this cohort. In this study, we used poly-L-lactic acid electrospun scaffolds with two levels of fineness to support the development of ITT transplanted from transgenic donors to wild-type recipient mice. The purpose of this study was to evaluate the potential of ITT transplantation and spermatogenesis after using the two scaffolds, employing bioluminescence imaging for evaluation. The results suggest that ITT from 4-week-old mice possessed the most potential in spermatogenesis on the 70th day, together with the fine electrospun scaffolds. Moreover, bioluminescent imaging intensity was observed in recipient mice for up to 107 days, approximately six times more than the coarse electrospun scaffold and the control group. This occurs since the fine scaffold is more akin to the microenvironment of native testicular tissue as it reduces stiffness resulting from micronization and body fluid infiltration. The thermal analysis also exhibited recrystallization during the biodegradation process, which can lead to a more stable microenvironment. Overall, these findings present the prospect of fertility preservation in prepubertal males and could serve as a framework for future applications.     

Effect of baffle height and Reynolds number on fluid mixing

In this paper, both numerical simulation and experiment were performed to investigate the mixing process within mixing chambers of the planar micromixer with three baffles at varied baffle height. The presence of three baffles causes the flow to separate and creates the recirculation and back flow within mixing chambers. The fluid mixing was greatly influenced by the baffle height and Reynolds number (Re) related to the size of recirculation zone. Larger baffle height or Re produces larger recirculation zone and convective mixing. The micromixer with 350 μm high baffles in 400 μm wide channel results in over 95% mixing at Re = 80 from the simulation results. The experiment results confirm the above simulation results qualitatively. This planar micromixer has the merits of simple design and easy fabrication as compared to the three-dimensional passive micromixers.     

Antioxidant activities of aqueous extracts of selected plants

The antioxidant properties of 25 edible tropical plants, expressed as Trolox equivalent antioxidant capacity (TEAC), were studied using DPPH (1,1-diphenyl-2-picrylhydrazyl free radical) scavenging and reducing ferric ion antioxidant potential (FRAP) assays. Their cupric ion chelating activities (CCA) and total polyphenol contents (TPC) were also determined. A strong correlation between TEAC values obtained for the DPPH assay (TEAC_DPPH) and those for the FRAP assay (TEAC_FRAP) implied that compounds in the extracts were capable of scavenging the DPPH free radical and reducing ferric ions. A satisfactory correlation of TPC with TEAC_DPPH and TEAC_FRAP suggested that polyphenols in the extracts were partly responsible for the antioxidant activities while its correlation with CCA was poor, indicating that polyphenols might not be the main cupric ion chelators. Principal component analysis (PCA) indicated that TEAC_DPPH, TEAC_FRAP and TPC contributed to the total variation in the antioxidant activities of the plants.     

A module‐integrated isolated solar micro‐inverter without electrolytic capacitors

This paper presents a module‐integrated isolated solar micro‐inverter. The studied grid‐tied micro‐inverters can individually extract the maximum solar power from each photovoltaic (PV) panel and transfer to the AC utility system. A harmonic suppression technique is used to reduce the DC‐bus capacitance. Electrolytic capacitors are not needed in the studied solar micro‐inverter. High conversion efficiency, high maximum power point tracking accuracy and long lifespan can be achieved. The operation principles and design considerations of the studied PV inverter are analyzed and discussed. A laboratory prototype is implemented and tested to verify its feasibility. Copyright © 2012 John Wiley & Sons, Ltd.     

Sentences over Integral Domains and Their Computational Complexities

LetRbe a Hilbertian domain and letKbe its fraction field. Letψ(x₁, …, x_n, y) be a quantifier free arithmetical formula overR. We may also takeψ(x₁, …, x_n, y) to be an arithmetical formula overK[x₁, …, x_n] and write it asψ(y). In this paper we show that ifRhas enough non-units and x₁…x_n y ψ(x₁, …, x_n, y), called an ⁿ  sentence, is true inR, then y ψ(y) is true inK[x₁, …, x_n]. Also, ifR=K[T], whereKis an infinite integral domain andx₁…x_n y ψ(x₁, …, x_n, y)is true inR, then y ψ(y) is true inR[x₁, …, x_n]. These results are applied to find the upper and lower bounds of the time complexities of various decision problems on diophantine equations with parameters and arithmetical sentences. Some of the results are: 1. The decision problem of sentences and diophantine equations with parameters over the ring of integers of a global field are co-NP-complete. 2. The decision problem of sentences over the ring of integers of a global field is NP-complete. 3. LetKbe an infinite domain, the time complexities of the decision problems of equations with parameters and sentences over the polynomial ringK[t] are polynomial time reducible to factoring polynomials overK. 4. The decision problem of sentences over all algebraic integer rings is in P. 5. The decision problem of sentences over all integral domains with characteristic 0 is in P. 6. The time complexity of the decision problem of sentences over all integral domains is polynomial time reducible to factoring integers overZand factoring polynomials over finite fields.