Context in word recognition

Relatively low character error rates can often lead to prohibitive levels of word error rates. This paper examines several techniques for integrating an independent contextual postprocessor (CPP) into a full classification system. Using positional binary n-grams the CPP can correct many errors directly. In those cases where the correction process leads to ambiguity, the CPP can direct additional processing. Experimental results demonstrate that almost all of the derived improvement results from CPP-directed reclassification. This only requires that the CPP have the classifier likelihood fed forward to it. Therefore, a standardized CPP can be built independently of the rest of the classification system. An initial 45% word error rate is reduced to about a 2% word error rate and a 1% reject rate. Presence of a dictionary allows these figures to be reduced even further.     

Exploiting machine-specific pointer operations in abstract machines

Increasingly powerful machine instructions complicate abstract machine design for portability. Abstract machine instructions must be “larger” than the target machine instructions that they are to exploit, but they must not grow so large as to complicate the realization of the abstract machine on real machines. This paper presents related techniques for low-level yet machine-independent access to typical stack and string-processing instructions.     

Australian encephalitis in the Northern Territory: clinical and epidemiological features, 1987-1996

OBJECTIVES: The purpose of this study was to evaluate the contribution of the executive cognitive functions to self-reported and observed performance of activities of daily living and instrumental activities of daily living. DESIGN: These data were collected as part of a cross-sectional survey of community-dwelling older persons, using statistical sampling, in a two-county area of southern Colorado. SETTING: Participants were interviewed and administered measures of general cognition, depression, executive functioning, and performance of self-care and instrumental activities, either in their homes or at the study clinic. PARTICIPANTS: A total of 1158 community-dwelling persons between the ages of 60 and 99 participated. Of these, 657 were female, 501 were male, 637 were Hispanic, and 521 were non-Hispanic whites. MEASUREMENTS: Subjects were administered the Mini-Mental State Exam (MMSE), a measure of executive functioning (the Behavioral Dyscontrol Scale), the Center for Epidemiologic Studies Depression scale (CES-D), and the Structured Assessment of Independent Living Skills (SAILS, a measure of observed performance of daily tasks). They also were interviewed regarding their reported ADL and IADL status using measures from the Longitudinal Study on Aging. RESULTS: Both general mental status and executive functioning demonstrated statistically significant univariate associations with all seven functional status measures (both self-report and observed performance). In a series of ordinary least squares regression models, executive functioning was a predictor for self-reported ADLs and observed performance of complex IADL tasks such as managing money and medications. Mental status did not predict self-reported functioning but was a predictor of observed performance. Depression was a significant variable for self-report measures but not for observed performance. Executive functioning and general mental status demonstrated some degree of independence from one another. CONCLUSION: Executive functioning is an important determinant of functional status for both self-reported and observed ADLs and IADLs and should be assessed routinely when evaluating the mental status and functional abilities of older people. These results replicate and extend previous research on executive functioning among older persons by examining these factors in a large bi-ethnic community sample.     

基于故障本征证据和特征指标的换流变压器状态评估

针对当前状态评估指标体系对带故障运行的换流变压器"评估死区"的问题,提出一种基于故障本征证据和特征指标的换流变压器状态评估方法。分析了换流变压器阀侧绕组的绝缘特性并选取适用于换流变压器状态评估的故障类型和指标量;采用数据驱动的模糊层次分析法提取故障类型的特征指标,并用关联规则提取故障类型的本征证据集,得到拓宽的状态评估指标体系;引入变权思想突出劣化指标对整体状态估计的影响,以反映换流变压器的真实运行状态,对故障设备的二次评估拓宽了状态评估的应用范围。实例分析结果表明,该方法对换流变压器故障判定的准确率更高,故障识别和故障程度的二次评估使状态评估结果更具实践价值。     

Random phase plate for wavefront sensing via phase retrieval and a volume speckle field

A random phase plate is prepared by illuminating a photoresist plate with a fully developed speckle field and using the developed phase plate (DPP) as a diffuser. Wavefront sensing is implemented using phase retrieval based on the recording of speckle intensity patterns at various distances from the DPP and the wave propagation equation. The effects of the roughness height of the DPP on the phase retrieval are investigated. From simulations a roughness height of lambda/10 results in a speckle field that yields good phase reconstruction for the spherical test wavefront incident on the DPP. From the experiments different portions of the DPP that received varying exposures are examined. A section of the phase plate with a characteristic roughness height facilitated the generation of a speckle field that is optimum for the phase retrieval algorithm. Thus a random phase plate with varying roughness height allows optimized measurements of wavefronts with different curvatures. Analytical expressions describing the second-order intensity statistics (fourth-order field statistics) for a field traversing a specific diffuser are presented. This DPP will not give rise to a fully developed speckle field, but knowing the statistics of the depth of the DPP will facilitate a rigorous treatment of the problem.     

Ceria-based Catalysts for the Production of H2 Through the Water-gas-shift Reaction: Time-resolved XRD and XAFS Studies

Hydrogen is a potential alternate energy source for satisfying many of our energy needs. In this work, we studied H₂ production from the water-gas-shift (WGS) reaction over Ce_1?x Cu _x O₂ catalysts, prepared with a novel microemulsion method, using two synchrotron-based techniques: time-resolved X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS). The results are compared with those reported for conventional CuO _x /CeO₂ and AuO _x /CeO₂ catalysts obtained through impregnation of ceria. For the fresh Ce_1?x Cu _x O₂ catalysts, the results of XAFS measurements at the Cu K-edge indicate that Cu is in an oxidation state higher than in CuO. Nevertheless, under WGS reaction conditions the Ce_1?x Cu _x O₂ catalysts undergo reduction and the active phase contains very small particles of metallic Cu and CeO_2?x . Time-resolved XRD and XAFS results also indicate that Cu^δ+ and Au^δ+ species present in fresh CuO _x /CeO₂ and AuO _x /CeO₂ catalysts do not survive above 200 °C under the WGS conditions. In all these systems, the ceria lattice displayed a significant increase after exposure to CO and a decrease in H₂O, indicating that CO reduced ceria while H₂O oxidized it. Our data suggest that H₂O dissociation occurred on the O_vacancy sites or the Cu–O_vacancy and Au–O_vacancy interfaces. The rate of H₂ generation by a Ce_0.95Cu_0.05O₂ catalyst was comparable to that of a 5 wt% CuO _x /CeO₂ catalyst and much bigger than those of pure ceria or CuO.     

阳离子无醛固色剂的合成与应用

以二乙烯三胺和双氰胺为主要原料合成了一种符合环保要求的无甲醛固色剂,应用到直接染料的固色实验中。实验表明,二乙烯三胺和氯化铵合成的仲胺盐与等物质量的双氰胺在130℃下的缩合产物具有优良的固色性能。其最佳的固色条件是:固色剂浓度为1 g/L,固色温度为60℃,浴比为20,固色pH值为9,处理后的纺织物耐皂洗牢度(白布沾色)达4级,湿摩擦色牢度达3~4级,与固色剂Y相比,可使直接染料的各项色牢度提高0.5~1.5级。     

CPVC／PVC与CPVC／ABS合金加工性能研究

研究了聚氯乙烯(PVC)与丙烯腈-丁二烯-苯乙烯共聚物(ABS)用量对氯化聚氯乙烯(CPVC)/PVC、CPVC/ABS合金最低塑化温度Tmin、塑化时间t、平衡扭矩TQ等加工性能以及体系的热稳定性的影响;同时对合金的耐热性能进行了分析.结果表明,随着体系中PVC、ABS用量的增加,CPVC/PVC、CPVC/ABS合金的Tmin、t和TQ降低,而体系的热稳定性增加.     

Field tests of surface seals and soil treatments to reduce fumigant emissions from shank injection of Telone C35

A mixture of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) (Telone C35) is an increasingly used fumigant product for pre-plant soil fumigation in California, USA. Atmospheric emissions of volatile organic compounds, including these important pesticides, is more heavily regulated in an effort to improve air-quality. Research has identified various methods of reducing fumigant emissions but effective and economically feasible field methods are still needed. The objective of this field study was to determine the effectiveness of several surface seal and soil treatment methods on emissions of 1,3-D and CP from shank-injected Telone C35. Treatments included control (bare surface), pre-irrigation (irrigation prior to fumigation), post-fumigation water seals with or without potassium thiosulfate (KTS) amendment, and standard high density polyethylene (HDPE) tarp over soils amended with either KTS or composted manure. The two KTS treatments resulted in the lowest fumigant emissions; but the soil surface in the treatments developed a reddish-orange color and an unpleasant odor that lasted for a few months. The pre-irrigation reduced emissions more than post-application water seals. An application of composted manure at 12.4 Mg ha(- 1) spread over the soil surface followed by HDPE tarp did not reduce 1,3-D emissions compared to the bare soils in this trial, indicating that a better understanding of processes is required in order to effectively use organic amendments for minimizing fumigant emissions. Chloropicrin emissions were generally lower than 1,3-D for all treatments.