Two Studies that Investigate the Impact of Ceiling and Wall Reflectance Values on LEED Credits

This study is divided into two parts. The first study determines window size and size reductions for different wall and ceiling reflectance combinations that are needed in a classroom to achieve one leadership in energy and environmental design (LEED) daylight factor credit. The second study determines the power consumption of indirect luminaires with a target illuminance of 538?lux for different wall and ceiling reflectance combinations. LEED credits for the optimizing energy performance are determined. It is found that ceiling reflectance has a higher impact on light levels and energy performance than wall reflectance. A ceiling reflectance of 90% and wall reflectance of 75% allows a minimum window-to-wall ratio of 0.444 to achieve one LEED daylight factor credit. The same room decreases lighting power density for an indirect fluorescent lighting system by one-third below the maximum permissible lighting power density specified in American Society of Heating, Refrigerating and Air-Conditioning Engineers/Illuminating Engineering Society of North America (ASHRAE/IESNA) Standard 90.1-2001. If lighting constitutes 50% of the total ASHRAE/IESNA 90.1 load, 0.92 LEED credits for the optimization of energy performance can be obtained for new construction and 2.92 credits can be obtained for existing buildings.     

PCS/W-CDMA dual-band MMIC power amplifier with a newly proposed linearizing bias circuit

A personal communications service/wide-band code division multiple access (PCS/W-CDMA) dual-band monolithic microwave integrated circuit (MMIC) power amplifier with a single-chip MMIC and a single-path output matching network is demonstrated by adopting a newly proposed on-chip linearizer. The linearizer is composed of the base-emitter diode of an active bias transistor and a capacitor to provide an RF short at the base node of the active bias transistor. The linearizer enhances the linearity of the power amplifier effectively for both PCS and W-CDMA bands with no additional DC power consumption, and has negligible insertion power loss with almost no increase in die area. It improves the input 1-dB gain compression point by 18.5 (20) dB and phase distortion by 6.1/spl deg/ (12.42/spl deg/) at an output power of 28 (28) dBm for the PCS (W-CDMA) band while keeping the base bias voltage of the power amplifier as designed. A PCS and W-CDMA dual-band InGaP heterojunction bipolar transistor MMIC power amplifier with single input and output and no switch for band selection is embodied by implementing the linearizer and by designing the amplifier to have broad-band characteristics. The dual-band power amplifier exhibits an output power of 30 (28.5) dBm, power-added efficiency of 39.5 % (36 %), and adjacent channel power ratio of -46 (-50) dBc at the output power of 28 (28) dBm under 3.4-V operation voltage for PCS (W-CDMA) applications.     

Evaluation of Robust Classifier Algorithm for Tissue Classification under Various Noise Levels

Ultrasonic surgical devices are routinely used for surgical procedures. The incision and coagulation of tissue generate a temperature of 40 °C–150 °C and depend on the controllable output power level of the surgical device. Recently, research on the classification of grasped tissues to automatically control the power level was published. However, this research did not consider the specific characteristics of the surgical device, tissue denaturalization, and so on. Therefore, this research proposes a robust algorithm that simulates noise to resemble real situations and classifies tissue using conventional classifier algorithms. In this research, the bioimpedance spectrum for six tissues (liver, large intestine, kidney, lung, muscle, and fat) is measured, and five classifier algorithms are used. A signal‐to‐noise ratio of additive white Gaussian noise diversifies the testing sets, and as a result, each classifier's performance exhibits a difference. The k‐nearest neighbors algorithm shows the highest classification rate of 92.09% () and a standard deviation of 1.92%, which confirms high reproducibility.     

BER minimization for dual‐polarized wireless systems with polarization‐domain rotation

We consider the problem of bit error rate (BER) degradation because of the power gain imbalance between horizontal (H)‐polarization and vertical (V)‐polarization components in an orthogonal dual‐polarization transmission system. To alleviate the aforementioned BER degradation problem, we propose a non‐orthogonal polarization‐domain rotation scheme where the axes of H‐polarization and V‐polarization components are rotated with different angles at the transmitter and de‐rotated at the receiver. In addition, in order to assess the effectiveness of the polarization‐domain rotation scheme, we derive the closed‐form BER expression under a practical dual‐polarized channel model, which is represented by cross‐polarization ratio and co‐polarization ratio (CPR). We also derive the approximated BER expressions for the two asymptotic values of CPR: balanced CPR and infinite CPR. With the derived BER expressions, we find the optimal rotation angles that jointly minimize the BER. According to the numerical results, it is shown that about 3dB E_b/N₀ gain is obtained at the BER of 10^?4 and the CPR of 10dB by the polarization‐domain rotation scheme with optimal rotation angles compared with the conventional orthogonal dual‐polarization transmission. Copyright © 2015 John Wiley & Sons, Ltd.     

Cost Effective Silica‐Based 100 G DP‐QPSK Coherent Receiver

We present a cost‐effective dual polarization quadrature phase‐shift coherent receiver module using a silica planar lightwave circuit (PLC) hybrid assembly. Two polarization beam splitters and two 90° optical hybrids are monolithically integrated in one silica PLC chip with an index contrast of 2%‐Δ. Two four‐channel spot‐size converter integrated waveguide‐photodetector (PD) arrays are bonded on PD carriers for transverse‐electric/transverse‐magnetic polarization, and butt‐coupled to a polished facet of the PLC using a simple chip‐to‐chip bonding method. Instead of a ceramic sub‐mount, a low‐cost printed circuit board is applied in the module. A stepped CuW block is used to dissipate the heat generated from trans‐impedance amplifiers and to vertically align RF transmission lines. The fabricated coherent receiver shows a 3‐dB bandwidth of 26 GHz and a common mode rejection ratio of 16 dB at 22 GHz for a local oscillator optical input. A bit error rate of is achieved at a 112‐Gbps back‐to‐back transmission with off‐line digital signal processing.     

Application of an in situ bismuth-coated glassy carbon electrode for electroanalytical determination of Cd (II) and Pb (II) in Korean polished rices

Rapid on-site monitoring of heavy metals in plants is necessary to minimize the exposure of humans to the contaminated food. The potential of using anodic stripping voltammetry (ASV) for simultaneous determination of cadimium (Cd) and lead (Pb) in rice was evaluated. Eight different Korean polished rices were digested using concentrated HNO₃ solution in a microwave oven. The peak currents measured with an in situ bismuth-coated electrode were linearly proportional to Cd and Pb concentrations (1.5 to 200 ppb) in 0.1 M HNO₃ (R² ⩾0.98). The electrode was feasible for measuring Pb in acid digests of the tested polished rices with measurement errors of <16.3 ppb. However, even though there was acceptable agreement in 4 of the 8 samples tested for Cd between the ASV and inductively coupled argon plasma (ICP) methods, further studies would be needed to improve the predictive capability of the electrode while reducing the variability in measurement and lowering the detection limit.     

Fabrication and characterization of PZT (lead zirconate titanate) bridge-shaped resonator for mass sensing application

Our research, based on executing theoretical modeling depending on the dimensions of PZT (lead zirconate titanate) thin film, was applied to two different bridge-shaped resonators. The critical point of having two different types of resonators is that it is a way of releasing the bridge. The first type of bridge-shaped resonator is released through use of an isotropic etching method using XeF₂ gas, while the second type of bridge-shaped resonator is released by a wet etching method that uses a KOH solution. The bridge-shaped resonators are anticipated to have accurate mass detecting sensors based on high mass sensitivity compared to the other shapes, such as diaphragms and cantilevers. The feasibility of a bridge-shaped PZT resonator as a mass sensor has been researched through studying the resonant frequency shift of a bridge-shaped resonator. The actual resonant properties of bridge-shaped resonators were determined by measuring resonant frequency and Q-factor measurements using an LDV (Laser Doppler Vibrometer). The resonant frequency appears in the ranges of 378.4?C419.8, 144.0?C180.3, and 107.8?C123.4?kHz for dimensions of 50???m?×?250???m, 100???m?×?500???m, and 150???m?×?750???m, respectively. Finally, four different thicknesses of Titanium (Ti) were loaded on the bridge-shaped resonator to confirm its variation and mass sensitivity. Significantly, mass sensitivities with dimensions of 50???m?×?250???m, 100???m?×?500???m, and 150???m?×?750???m were 2.02?Hz/pg, 330.42?Hz/ng, and 43.67?Hz/ng, respectively. Thus, the bridge-shaped resonator with dimensions of 50???m?×?250???m was able to detect the picogram-level of a mass.     

Effect of oxygen flow rate on ITO thin films deposited by facing targets sputtering

Tin-doped indium oxide (ITO) thin films were deposited on glass substrates at various oxygen flow rates using a planar magnetron sputtering system with facing targets. In this system, the strong internal magnets inside the target holders confine the plasma between the targets. High resolution transmission electron microscopy revealed a combination of amorphous and crystalline phases on the glass substrate. X-ray photoelectron spectroscopy suggested that the decrease in carrier concentration and increase in mobility were caused by a decrease in the concentration of Sn⁴⁺ states. The electrical and optical properties of the ITO films were examined by Hall measurements and UV-visible spectroscopy, which showed a film resistivity and transmittance of 4.26 × l0⁻⁴ Ω cm, and > 80% in the visible region, respectively.     

Post-growth annealing and wide bandgap modulation of BeZnO layers grown by RF co-sputtering of ZnO and Be targets

ZnO based oxide system Be _x Zn_1−x O alloy of various compositions has been successfully grown by the RF co-sputtering method. The crystallinity of the Be _x Zn_1−x O alloys has been remarkably improved after the post-annealing at 600 °C compared with the Be _x Zn_1−x O alloys post-annealed at other temperatures. The x value of the Be _x Zn_1−x O layers has been increased from 0.022 to 0.17 by adjusting the RF-power of the Be target. Also, the optical bandgap energy has been modulated from 3.2218 to 3.7978 eV, respectively. Based on our results, a bandgap bowing parameter of Be _x Zn_1−x O alloy has been extracted out to be 4.5 eV. These findings could be useful to fabricate the ZnO/Be _x Zn_1−x O quantum structures and bandgap modulation for deep ultraviolet-light-emitting diodes.