A label-setting algorithm for finding a quickest path

The quickest path problem is to find a path to send a given amount of data from the source to the destination with minimum transmission time. To find the quickest path, existing algorithms enumerate non-dominated paths with distinct capacity, and then determine a quickest path by comparing their transmission time. In this paper, we propose a label-setting algorithm for finding a quickest path by transforming a network to another network where an important property holds that each subpath of a quickest path is also a quickest path. The proposed algorithm avoids enumerating non-dominated paths whose transmission time is greater than the minimum transmission time. Although the computational complexity of the proposed algorithm is the same as that of existing algorithms, experimental results show that our algorithm is efficient when a network has two or more non-dominated paths.     

A novel EER structure for reducing complexity using negative resistance amplifier

This letter presents a novel envelope elimination and restoration (EER) structure using the negative resistance class F power amplifier. Due to the extremely high gain characteristic of the negative resistance amplifier in very narrow bandwidth, it operates in saturation mode. This characteristic is applied to the proposed EER. Using this technique, a limiter, a drive amplifier, and a class F power amplifier in conventional EER can be substituted with the negative resistance class F power amplifier. This technique greatly reduces the complexity of conventional EER without degradation of efficiency and linearity. The measured results show efficiency of 60% and less than-26 dBc IMD levels for two-tone test in PCS band at 27-dBm output power.     

A power re-use technique for improved efficiency of pulsed oscillating amplifiers

This letter presents a power re-use technique for pulsed oscillating amplifiers. By rectifying the upconverted switching harmonics of the pulsed oscillating output, some portions of wasted power can be returned to the power supply. The efficiency of the amplifier can be enhanced without degradation of the linearity. The measured results show that the overall efficiency of the amplifier with power re-use is improved up to 22% compared to the pulsed oscillating amplifier without the power re-use at the PCS band.     

Bid-markup determination for microtunneling projects

Determining the right size of bid-markup is not an easy task for a contractor. The markup must be low enough to ensure a good chance of winning a contract, but high enough to realize a reasonable profit. The determination of proper markup involves the consideration of numerous factors. In the underground construction portions, the factors considered can be increased because of uncertain subsurface conditions. Even though microtunneling has gained in popularity since it was first introduced into North America in 1984, little has been studied as to the contractors’ behavior toward the determination of bid-markup or the systematic bid-markup processes. This paper discusses the key factors that affect the bid-markup decision in the relatively novel construction area and identifies the level of impact of each factor through the use of analytical methods. In addition, a decision support system (DSS) to assist in the selection of appropriate bid-markup for microtunneling projects is developed through survey results and various analytical methods. Finally, a sensitivity analysis is performed.     

Fabrication of TiO2/Tin-doped indium oxide-based photoelectrode coated with overlayer materials and its photoelectrochemical behavior

The photoelectrochemical properties of TiO2-based photoelectrodes with metal oxide overlayers (e.g., ZnO, ZrO2, MgO, and Al2O3) were investigated. The metal oxides were deposited on TiO2/tin-doped indium oxide (ITO) films by spin-coating metal-alkoxide precursors. The formation of the overlayers was confirmed by energy dispersive X-ray spectroscopy (EDS) and high resolution transmission electron microscopy (HRTEM). Each overlayers were well-coated on the TiO2-based films and have approximately 2 nm thickness. The prepared films were used as photoanodes in a photoelectrochemical system with a Pt counter electrode to evaluate hydrogen production performance. Comparing with other overlayers, the ZnO-coated photoelectrode exhibits the highest rate of hydrogen evolution and which is better than the uncoated one. From the photoelectrochemical and spectroscopic study, the superior hydrogen production property of the ZnO-coated TiO2 photoelectrode was attributed to both the higher light absorbance of ZnO compared to TiO2 and the formation of hydroxyl groups at the ZnO surface.     

A new phase noise reduction method of oscillator by loaded Q improvement using dual feedback topology

This letter presents a new method to reduce the phase noise in oscillator based on the loaded Q improvement approach. A hairpin resonator is weakly coupled to the two microstrip lines to improve the loaded Q of it and the dual feedback topology is used to enable the start-up oscillation condition to be satisfied. The high loaded Q property of the resonator in the proposed oscillator circuit is analyzed using the CAD simulation. For comparison the phase noise performances of the conventional hairpin resonator oscillator and the oscillator using the dual feedback are measured. Measurements show that the oscillator using the dual feedback exhibits a low phase noise performance of -109.1 dBc/Hz at 100-kHz offset at 10 GHz, which is reduced by about 10 dB compared to that of the conventional one.     

Modulating Photoluminescence of Monolayer Molybdenum Disulfide by Metal–Insulator Phase Transition in Active Substrates

The atomic thickness and flatness allow properties of 2D semiconductors to be modulated with influence from the substrate. Reversible modulation of these properties requires an “active,” reconfigurable substrate, i.e., a substrate with switchable functionalities that interacts strongly with the 2D overlayer. In this work, the photoluminescence (PL) of monolayer molybdenum disulfide (MoS₂) is modulated by interfacing it with a phase transition material, vanadium dioxide (VO₂). The MoS₂ PL intensity is enhanced by a factor of up to three when the underlying VO₂ undergoes the thermally driven phase transition from the insulating to metallic phase. A nonvolatile, reversible way to rewrite the PL pattern is also demonstrated. The enhancement effect is attributed to constructive optical interference when the VO₂ turns metallic. This modulation method requires no chemical or mechanical processes, potentially finding applications in new switches and sensors.     

An Efficient Dictionary Organization for Maximum Diagnosis

The major problem of fault diagnosis with a fault dictionary is the enormous amount of data. The technique used to manage this data can have a significant effect on the outcome of the fault diagnosis procedure. If information is removed from a fault dictionary in order to reduce the size of the dictionary, its ability to diagnose stuck-at faults and unmodeled faults may be severely debased. Therefore, we focus on methods for producing a dictionary that is both small and lossless-compacted. We propose an efficient dictionary for maximum diagnosis, which is called SD-Dictionary. This dictionary consists of a static sub-dictionary and a dynamic sub-dictionary in order to make a smaller dictionary while maintaining the critical information needed for the diagnostic ability. Experimental results on ISCAS’ 85, ISCAS’ 89 and ITC’ 99 benchmark circuits show that the size of the proposed dictionary is substantially reduced, while the dictionary retains most or all of the diagnostic capability of the full dictionary. This work was supported by the “System IC 2010” project of Korea Ministry of Science and Technology and Ministry of Commerce, Industry and Energy. Editor: Y. Takamatsu Sunghoon Chun received the B.S. degrees in Electrical and Electronic Engineering from Yonsei University, Seoul, Korea, in 2002. He was a Reseach Engineer with ASIC Research Center in Yonsei University. He researched for test methodologies for SoC. He received the M.S. degrees in Electrical and Electronic Engineering from Yonsei University in 2005. He is currently working toward Ph.D. degree in Electrical and Electronic Engineering at Yonsei University. His area of interests includes SoC testing, delay testing, fault diagnosis, functional testing for processor based system and test methodologies for signal integrity faults. Sangwook Kim received the B.S., and M.S. degrees in Electrical and Electronic Engineering from Yonsei University, Seoul, Korea, in 1999, and 2001, respectively. He researched for Digital Signal Processor design and fault diagnosis of VLSI. He is a Research Engineer with SoC Design Group of System IC Division in LG Electronics, Inc. He is currently interested in SoC design for HDTV and design verification. Hong-Sik Kim was born in Seoul, Korea, on April 4, 1973. He received the B.S., M.S. and Ph.D. degrees in Electrical and Electronic Engineering from Yonsei University, Seoul, Korea, in 1977, 1999, and 2004, respectively. He was a Post-Doctorial Fellow with the Institute of Virginia Technology. He is currently working on System LSI Group in the Samsung Electronics. His current research interest includes design-for-testability, built-in self tests and fault diagnosis. Sungho Kang received the B.S. degree from Seoul National University, Seoul, Korea, and the M.S. and Ph.D. degrees in electrical and computer engineering from The University of Texas at Austin. He was a Post-Doctorial Fellow with the University of Texas at Austin, a Research Scientist with the Schlumberger Laboratory for Computer Science, Schlumberger Inc., and a Senior Staff Engineer with the Semiconductor Systems Design Technology, Motorola Inc. Since 1994, he has been an Associate Professor with the Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea. His current research interests include VLSI design, VLSI CAD and VLSI testing and design for testability.     

Combustion and emission characteristics of a dual injection system applied to a DISI engine

Concerns about environmental pollution and energy shortages have increased worldwide. One approach to reduce CO2 emissions from gasoline engines is to achieve stratified charge combustion with various injection ratios using port fuel injection （PFI） and direct injection. The combustion and emission characteristics of a 4-valve direct injection spark ignition （DISI） engine equipped with a dual injection system were investigated while the injection ratio was varied. When the direct injection ratio increased, the lean limit A/F was extended. This suggests that the dual injection gasoline engine with both PFI and direct injection can meet severe vehicle emission and fuel economy requirements. The dual injection system had higher combustion pressure than that of either a conventional or direct injection systems. Therefore, the engine power of a dual injection DISI engine would be higher than that of a single injection DISI engine. However, NOx emissions increased compared with the emission levels in both PFI and DISI systems.     

A spiral-shaped defected ground structure for coplanar waveguide

The authors present a spiral-shaped defected ground structure for coplanar waveguides (DGSCPW), which can be used as a kind of periodic structure for a planar transmission line. The proposed spiral-DGSCPW adopts spiral-shaped defects on both ground planes of CPW. Due to the spiral-shaped defects, the equivalent shunt inductance and slow-wave effects increase more rapidly than the standard CPW or CPW lines combined with the conventional PBG. The modeling and analysis to extract the equivalent circuit, increased slow-wave factor, and simulated and measured performances are presented.