Using nanoparticles to synthesize erbium-doped light-emitting thin film

We applied Er₂O₃ nanoparticles, P₂O₅ particles, and spin-on-glass (SOG) solution to form erbium-doped silica thin films exhibiting photoluminescence at 1530 nm. We further investigated the annealing condition and composition of the spin-coated film. The addition of P₂O₅ improved PL peak intensity of the erbium-doped film fivefold. The weight ratio of Er₂O₃ nanoparticles to P₂O₅ particles in the SOG was found to be 0.54 for efficient light emission.     

On the temperature sensitivity of 1.5-/spl mu/m GaInNAsSb lasers

We analyze the temperature sensitivity of 1.5-/spl mu/m GaInNAsSb lasers grown on GaAs. Building on the method of Tansu and coworkers, we find evidence that the characteristic temperatures for the threshold current T/sub 0/ and external efficiency T/sub 1/ are balanced by a combination of monomolecular recombination and temperature destabilizing mechanism(s) near room temperature. At elevated temperatures, the destabilizing process(es) dominate, due to increased threshold current density J/sub th/. While it is difficult to definitively identify carrier leakage, Auger recombination, or a combination of the two as the responsible mechanism(s), results indicate that carrier leakage certainly plays a role. Evidence of intervalence band absorption was also found; T/sub 1/ was reduced, but J/sub th/ and T/sub 0/ were not significantly degraded. Conclusions are corroborated by supporting measurements of the Z-parameter with bias, spontaneous emission spectrum, and band-offsets. Spontaneous emission measurements show evidence of weak Fermi-level pinning within the active region at threshold, indicating a form of carrier leakage. This is consistent with the characteristic temperature analysis and a leakage mechanism is proposed. This process is partially responsible for the greater temperature sensitivity of device parameters and the poor internal efficiency. Methods for reducing the effects of each parasitic mechanism are also described.     

刀熔控制单元ＡＳＦＣ在ＡＣＳ８００传动中的应用

刀熔控制单元ASFC在ACS800传动中应用比较广泛,特别在ACS800外型规格为R8i逆变单元的充电回路中的应用尤为广泛,由于逆变模块是通过刀熔开关连接在直流母排上的,所以在合闸时,会有很大的冲击电流,通过ASFC的检测和控制,可降低合闸时冲击电流,从而保护逆变单元。     

Design and analysis of power‐CMOS‐gate‐based switched‐capacitor DC–DC converter with step‐down and step‐up modes

A unified multi‐stage power‐CMOS‐transmission‐gate‐based quasi‐switched‐capacitor (QSC) DC–DC converter is proposed to integrate both step‐down and step‐up modes all in one circuit configuration for low‐power applications. In this paper, by using power‐CMOS‐transmission‐gate as a bi‐directional switch, the various topologies for step‐down and step‐up modes can be integrated in the same circuit configuration, and the configuration does not require any inductive elements, so the IC fabrication is promising for realization. In addition, both large‐signal state‐space equation and small‐signal transfer function are derived by state‐space averaging technique, and expressed all in one unified formulation for both modes. Based on the unified model, it is all presented for control design and theoretical analysis, including steady‐state output and power, power efficiency, maximum voltage conversion ratio, maximum power efficiency, maximum output power, output voltage ripple percentage, capacitance selection, closed‐loop control and stability, etc. Finally, a multi‐stage QSC DC–DC converter with step‐down and step‐up modes is made in circuit layout by PSPICE tool, and some topics are discussed, including (1) voltage conversion, output ripple percentage, and power efficiency, (2) output robustness against source noises and (3) regulation capability of converter with loading variation. The simulated results are illustrated to show the efficacy of the unified configuration proposed. Copyright © 2003 John Wiley & Sons, Ltd.     

The assessment of scattered light in ophthalmic materials

The assessment of scattered light in lenses, sunglasses and eye protection has been carried out in various ways. Wide‐angle scatter (haze) is used in the United States, Australia and New Zealand. Small‐angle scatter (light diffusion) is specified in Europe. Little is known of the relationships within and between the methods. In an international standard, a single method is generally required. The measurement of wide‐angle scatter (haze) (two variations of a method) and small‐angle scatter (light diffusion) (three variations of a method) were carried out on 12 samples, 4 abraded, 4 with inclusion defects and 4 with surface coating defects, in an international inter‐laboratory comparison. The consensus means and confidence limits were used to compare two haze methods: the “Basic” light diffusion method and two variations of the “Simplified” light diffusion method. For abraded samples, haze and light diffusion measures are linearly related. For the remaining samples, the haze method was a much more sensitive detector of low levels of light scatter. The three measures of light diffusion are highly linearly correlated. Haze is the more sensitive measure for lower levels of light scatter when due to smaller scattering elements. The Basic and Simplified methods are highly linearly correlated. The red laser Simplified method returns a value 10% lower than that of the Basic method, and the green laser Simplified method returns a value 12% higher than that of the Basic method. These can be accounted for by a calibration factor or different acceptance values. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 416–423, 2016     

Value of serum inorganic phosphate in the diagnosis of ischemic bowel disease

To clarify the value of the serum inorganic phosphate concentration in the diagnosis of ischemic bowel disease, a retrospective study of 24 patients with various causes of intestinal ischemia was carried out. Only 25 percent of the patients had elevations of their serum phosphate concentrations. These patients had the combination of extensive bowel injury, acute renal insufficiency, and acidosis. Mortality was significantly increased in these patients. Thus, the serum phosphate concentration was not a sensitive indicator of ischemic bowel disease, but elevations did predict extensive injury and poor prognosis.     

Fault-based test suite prioritization for specification-based testing

Context

Existing test suite prioritization techniques usually rely on code coverage information or historical execution data that serve as indicators for estimating the fault-detecting ability of test cases. Such indicators are primarily empirical in nature and not theoretically driven; hence, they do not necessarily provide sound estimates. Also, these techniques are not applicable when the source code is not available or when the software is tested for the first time.

Objective

We propose and develop the novel notion of fault-based prioritization of test cases which directly utilizes the theoretical knowledge of their fault-detecting ability and the relationships among the test cases and the faults in the prescribed fault model, based on which the test cases are generated.

Method

We demonstrate our approach of fault-based prioritization by applying it to the testing of the implementation of logical expressions against their specifications. We then validate our proposal by an empirical study that evaluates the effectiveness of prioritization techniques using two different metrics.

Results

A theoretically guided fault-based prioritization technique generally outperforms other techniques under study, as assessed by two different metrics. Our empirical results also show that the technique helps to reveal all target faults by executing only about 72% of the prioritized test suite, thereby reducing the effort required in testing.

Conclusions

The fault-based prioritization approach is not only applicable to the instance empirically validated in this paper, but should also be adaptable to other fault-based testing strategies. We also envisage new research directions to be opened up by our work.     

Multiresolution free form object modeling with point sampled geometry

In this paper an efficient framework for the creation of 3D digital content with point sampled geometry is proposed. A new hierarchy of shape representations with three levels is adopted in this framework. Based on this new hierarchical shape representation, the proposed framework offers concise integration of various volumetric- and surface-based modeling techniques, such as Boolean operation, offset, blending, free-form deformation, parameterization and texture mapping, and thus simplifies the complete modeling process. Previously to achieve the same goal, several separated algorithms had to be used independently with inconsistent volumetric and surface representations of the free-form object. Both graphics and industrial applications are presented to demonstrate the effectiveness and efficiency of the proposed framework.     

Incremental linear discriminant analysis for face recognition.

Dimensionality reduction methods have been successfully employed for face recognition. Among the various dimensionality reduction algorithms, linear (Fisher) discriminant analysis (LDA) is one of the popular supervised dimensionality reduction methods, and many LDA-based face recognition algorithms/systems have been reported in the last decade. However, the LDA-based face recognition systems suffer from the scalability problem. To overcome this limitation, an incremental approach is a natural solution. The main difficulty in developing the incremental LDA (ILDA) is to handle the inverse of the within-class scatter matrix. In this paper, based on the generalized singular value decomposition LDA (LDA/GSVD), we develop a new ILDA algorithm called GSVD-ILDA. Different from the existing techniques in which the new projection matrix is found in a restricted subspace, the proposed GSVD-ILDA determines the projection matrix in full space. Extensive experiments are performed to compare the proposed GSVD-ILDA with the LDA/GSVD as well as the existing ILDA methods using the face recognition technology face database and the Carneggie Mellon University Pose, Illumination, and Expression face database. Experimental results show that the proposed GSVD-ILDA algorithm gives the same performance as the LDA/GSVD with much smaller computational complexity. The experimental results also show that the proposed GSVD-ILDA gives better classification performance than the other recently proposed ILDA algorithms.     

A novel incremental principal component analysis and its application for face recognition.

Principal component analysis (PCA) has been proven to be an efficient method in pattern recognition and image analysis. Recently, PCA has been extensively employed for face-recognition algorithms, such as eigenface and fisherface. The encouraging results have been reported and discussed in the literature. Many PCA-based face-recognition systems have also been developed in the last decade. However, existing PCA-based face-recognition systems are hard to scale up because of the computational cost and memory-requirement burden. To overcome this limitation, an incremental approach is usually adopted. Incremental PCA (IPCA) methods have been studied for many years in the machine-learning community. The major limitation of existing IPCA methods is that there is no guarantee on the approximation error. In view of this limitation, this paper proposes a new IPCA method based on the idea of a singular value decomposition (SVD) updating algorithm, namely an SVD updating-based IPCA (SVDU-IPCA) algorithm. In the proposed SVDU-IPCA algorithm, we have mathematically proved that the approximation error is bounded. A complexity analysis on the proposed method is also presented. Another characteristic of the proposed SVDU-IPCA algorithm is that it can be easily extended to a kernel version. The proposed method has been evaluated using available public databases, namely FERET, AR, and Yale B, and applied to existing face-recognition algorithms. Experimental results show that the difference of the average recognition accuracy between the proposed incremental method and the batch-mode method is less than 1%. This implies that the proposed SVDU-IPCA method gives a close approximation to the batch-mode PCA method.