Helping online customers decide through Web personalization

The Web-based personalization system proposed here uses both collaborative filtering and Web usage mining to give online shoppers the personalized recommendations they need to purchase products more intelligently.     

External Cavity Lasers Composed of Higher Order Gratings and SLDs Integrated on PLC Platform

Very compact 4‐channel 200‐GHz‐spacing external cavity lasers (ECLs) were fabricated by hybrid integration of reflection gratings and superluminescent laser diodes on a planar lightwave circuit chip. The fifth‐order gratings as reflection gratings were formed using a conventional contact‐mask photo‐lithography process to achieve low‐cost fabrication. The lasing wavelength of the fabricated ECLs matched the ITU grid with an accuracy of ×0.1 nm, and optical powers were more than 0.4 mW at the injection current of 80 mA for all channels. The ECLs showed single mode operations with more than 30 dB side lobe suppression.     

Electronic and geometric effects of alkali promoters in CO hydrogenation over K/Mo2C catalysts

When potassium salts such as K₂CO₃, KOH, CH₃COOK, and K₂S were added to Mo₂C, the promoted catalysts showed high selectivities to alcohols and light olefins in CO hydrogenation at 573 K and 1.0 MPa. However, K₂SO₄ and KCl caused only slight increase in olefin selectivity with negligible alcohol formation. These two groups of promoters showed different physical and chemical states during the reaction as observed by AES, EDS, EPMA, IR and transient reaction behavior. This difference accounted for the observed difference in selectivity.     

Circuit and microarchitectural techniques for reducing cache leakage power

On-chip caches represent a sizable fraction of the total power consumption of microprocessors. As feature sizes shrink, the dominant component of this power consumption will be leakage. However, during a fixed period of time, the activity in a data cache is only centered on a small subset of the lines. This behavior can be exploited to cut the leakage power of large data caches by putting the cold cache lines into a state preserving, low-power drowsey mode. In this paper, we investigate policies and circuit techniques for implementing drowsy data caches. We show that with simple microarchitectural techniques, about 80%-90% of the data cache lines can be maintained in a drowsy state without affecting performance by more than 0.6%, even though moving lines into and out of a drowsy state incurs a slight performance loss. According to our projections, in a 70-nm complementary metal-oxide-semiconductor process, drowsy data caches will be able to reduce the total leakage energy consumed in the caches by 60%-75%. In addition, we extend the drowsy cache concept to reduce leakage power of instruction caches without significant impact on execution time. Our results show that data and instruction caches require different control strategies for efficient execution. In order to enable drowsy instruction caches, we propose a technique called cache subbank prediction, which is used to selectively wake up only the necessary parts of the instruction cache, while allowing most of the cache to stay in a low-leakage drowsy mode. This prediction technique reduces the negative performance impact by 78% compared with the no-prediction policy. Our technique works well even with small predictor sizes and enables a 75% reduction of leakage energy in a 32-kB instruction cache.     

Photocatalytic water splitting over ZrO2 prepared by precipitation method

ZrO₂ prepared by the precipitation method of zirconium oxychloride with various hydrolyzing agents was studied for photocatalytic water splitting reaction under UV light irradiation. The crystal structure as well surface properties were varied with the hydrolyzing agent of KOH, NH₄OH, and NH₂CONH₂. Especially, the surface area of the prepared ZrO₂ calcined at the same temperature of 750 °C for 6 h was dependent highly on the hydrolyzing agent, and thus the highest photocatalytic activity was obtained for ZrO₂ with the highest surface area when KOH was used as a hydrolyzing agent, In the presence of Na₂CO₃, the photocatalytic activity of ZrO₂ increased by 2–3 fold, which was ascribed to the physically adsorbed carbonate species on the ZrO₂ surface. This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University.     

Parallel algorithms for large applied problems: Issues and technologies

Topical issues of parallelizing computational methods and technologies for implementing the main mathematical modeling stages in solving a wide range of large applied problems are considered. Computation-information process models, classification of the main types of algorithms, and principles of their efficient mapping onto the distributed-and shared-memory computer architecture are described.     

A partially insulated field-effect transistor (PiFET) as a candidate for scaled transistors

Highly manufacturable partially insulated field-effect transistors (PiFETs) were fabricated by using Si-SiGe epitaxial growth and selective SiGe etch process. Owing to these technologies, pseudo-silicon-on-insulator (SOI) structures, partially insulating oxide (PiOX) under source/drain (PUSD) and PiOX under channel (PUC), could be easily realized with excellent structural and process advantages. We are demonstrating their preliminary characteristics and properties. Especially, in the PUSD PiFET, junction capacitance, leakage current, and DIBL in bulk devices could be reduced and the floating body problem in SOI devices was also cleared without any area penalty. Thus, this PiFET structure can be a promising candidate for the future DRAM cell transistor.     

Fluid simulation for self-similar traffic in generalized processor sharing servers

We propose a fluid simulation algorithm for generalized processor sharing (GPS) servers. We analyze the complexity of the proposed algorithm and show the advantage of fluid simulation, compared to packet-level simulation. Numerical results show that the simulation time can be much reduced by admitting some performance errors as the load is heavier and the self-similarity is higher.     

Posistor blocks of protection of automatic telephone exchanges

The thermal and electrical parameters of posistor blocks or protection of automatic telephone exchanges have been investigated. A mathematical model making it possible to optimize the posistor parameters for designing protective blocks with required characteristics has been proposed. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 5, pp. 88–93, September–October, 2006.     

Two-section InGaAsP/InP Fabry-Perot laser with a 12 nm tuning range

Wavelength tuning over a 12 nm range is obtained for a two-section InGaAsP/InP Fabry-Perot laser (λ=1.55 μm). The method used to vary the gain profile of the laser allows one to predict the range of possible wavelength tuning. Pis’ma Zh. Tekh. Fiz. 23, 10–15 (March 26, 1997)