A Fine-Grained Runtime Power/Performance Optimization Method for Processors with Adaptive Pipeline Depth

Recently,a method known as pipeline stage unification (PSU) has been proposed to alleviate the increasing energy consumption problem in modern microprocessors.PSU achieves a high energy efficiency by employing a changeable pipeline depth and its working scheme is eligible for a fine control method.In this paper,we propose a dynamic method to study fine-grained program interval behaviors based on some easy-to-get runtime processor metrics.Using this method to determine the proper PSU configurations during the program execution,we are able to achieve an averaged 13.5% energy-delay-product (EDP) reduction for SPEC CPU2000 integer benchmarks,compared to the baseline processor.This value is only 0.14% larger than the theoretically idealized controlling.Our hardware synthesis result indicates that the proposed method can largely decrease the hardware overhead in both area and delay costs,as compared to a previous program study method which is based on working set signatures.     

Facile preparation of platelike tungsten oxide thin film electrodes with high photoelectrode activity

Tungsten trioxide (WO(3)) thin film electrodes with platelike structures were prepared by a facile hydrothermal reaction of tungsten sheets in a dilute nitric acid solution at 100-180 °C and subsequent calcination at 450 °C. The calcination step facilitated the transformation of the crystal structure from tungsten oxide hydrates (WO(3)·H(2)O or WO(3)·2H(2)O) to monoclinic WO(3) without significant modification to the platelike structures. The photoelectrochemical performance of the thin film electrodes for water splitting that took place in a dilute sulfuric acid was strongly dependent on both temperature and the time used for the hydrothermal reaction. This suggests that the thickness of the film influences the process of photoexcited electron transport. The time required for the hydrothermal reaction under higher temperatures was reduced in the generation of thin film electrodes with high photoelectrode activity, because the crystal growth is accelerated at high temperatures and the electron transport is restricted by a relatively thick compact layer that is comprised of WO(3) nanoparticulates. The electrode exhibited sensitivity to the violet portion of the visible light spectrum due to the bandgap of 2.8 eV and high photoelectrode efficiency, as well as an incident photon-to-current conversion efficiency (IPCE) of 66.2%, for the photoelectrochemical oxidation of water.     

A single-atom transistor

The ability to control matter at the atomic scale and build devices with atomic precision is central to nanotechnology. The scanning tunnelling microscope can manipulate individual atoms and molecules on surfaces, but the manipulation of silicon to make atomic-scale logic circuits has been hampered by the covalent nature of its bonds. Resist-based strategies have allowed the formation of atomic-scale structures on silicon surfaces, but the fabrication of working devices-such as transistors with extremely short gate lengths, spin-based quantum computers and solitary dopant optoelectronic devices-requires the ability to position individual atoms in a silicon crystal with atomic precision. Here, we use a combination of scanning tunnelling microscopy and hydrogen-resist lithography to demonstrate a single-atom transistor in which an individual phosphorus dopant atom has been deterministically placed within an epitaxial silicon device architecture with a spatial accuracy of one lattice site. The transistor operates at liquid helium temperatures, and millikelvin electron transport measurements confirm the presence of discrete quantum levels in the energy spectrum of the phosphorus atom. We find a charging energy that is close to the bulk value, previously only observed by optical spectroscopy.     

Efficient Identification of the MYC Regulator with the Use of the CRISPR Library and Context-Matched Database Screenings

MYC is a major oncogene that plays an important role in cell proliferation in human cancers. Therefore, the mechanism behind MYC regulation is a viable therapeutic target for the treatment of cancer. Comprehensive and efficient screening of MYC regulators is needed, and we had previously established a promoter screening system using fluorescent proteins and the CRISPR library. For the efficient identification of candidate genes, a database was used, for which mRNA expression was correlated with MYC using datasets featuring “Similar” and “Not exactly similar” contexts. INTS14 and ERI2 were identified using datasets featuring the “Similar” context group, and INTS14 and ERI2 were capable of enhancing MYC promoter activity. In further database analysis of human cancers, a higher expression of MYC mRNA was observed in the INTS14 mRNA high-expressing prostate and liver cancers. The knockdown of INTS14 in prostate cell lines resulted in decreased MYC mRNA and protein expression and also induced G0/1 arrest. This study confirmed that CRISPR screening combined with context-matched database screening is effective in identifying genes that regulate the MYC promoter. This method can be applied to other genes and is expected to be useful in identifying the regulators of other proto-oncogenes.     

A propositional theorem prover to solve planning and other problems

Classical STRIPS-style planning problems are formulated as theorems to be proven from a new point of view: that the problem is not solvable. The result for a refutation-based theorem prover may be a propositional formula that is to be proven unsatisfiable. This formula is identical to the formula that may be derived directly by various “SAT compilers”, but the theorem-proving view provides valuable additional information not in the formula, namely, the theorem to be proven. Traditional satisfiability methods, most of which are based on model search, are unable to exploit this additional information. However, a new algorithm called “Modoc” is able to exploit this information and has achieved performance comparable to the fastest known satisfiability methods, including stochastic search methods, on planning problems that have been reported by other researchers, as well as formulas derived from other applications. Unlike most theorem provers, Modoc performs well on both satisfiable and unsatisfiable formulas. Modoc works by a combination of back-chaining from the theorem clauses and forward-chaining on tractable subformulas. In some cases, Modoc is able to solve a planning problem without finding a complete assignment because the back-chaining methodology is able to ignore irrelevant clauses. Although back-chaining is well known in the literature, a high level of search redundancy existed in previous methods; Modoc incorporates a new technique called “autarky pruning”, which reduces search redundancy to manageable levels, permitting the benefits of back-chaining to emerge, for certain problem classes. Experimental results are presented for planning problems and formulas derived from other applications. This revised version was published online in June 2006 with corrections to the Cover Date.     

杂交稻米的理化特性与食味评价的研究

本研究对籼型杂交稻米进行了包括理化特性的测定、食味感官评价及用食味计进行了成分测定和食味评价，探讨了日本常用的食味评价方法对中国产稻米的适应性，同时考察李稻米理化特性与食味的关连，并尝试建立了中国产稻米的食味推测式。