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1.
Justin Zobel  Philip Dart 《Software》1995,25(3):331-345
Approximate string matching is used for spelling correction and personal name matching. In this paper we show how to use string matching techniques in conjunction with lexicon indexes to find approximate matches in a large lexicon. We test several lexicon indexing techniques, including n-grams and permuted lexicons, and several string matching techniques, including string similarity measures and phonetic coding. We propose methods for combining these techniques, and show experimentally that these combinations yield good retrieval effectiveness while keeping index size and retrieval time low. Our experiments also suggest that, in contrast to previous claims, phonetic codings are markedly inferior to string distance measures, which are demonstrated to be suitable for both spelling correction and personal name matching.  相似文献   
2.
Biological nitrogen fixation (BNF) associated with trees and shrubs plays a major role in the functioning of many ecosystems, from natural woodlands to plantations and agroforestry systems, but it is surprisingly difficult to quantify the amounts of N2 fixed. Some of the problems involved in measuring N2 fixation by woody perennials include: (a) diversity in occurrence, and large plant-to-plant variation in growth and nodulation status of N2-fixing species, especially in natural ecosystems; (b) long-term, perennial nature of growth and the seasonal or year-to-year changes in patterns of N assimilation; and (c) logistical limitations of working with mature trees which are generally impossible to harvest in their entirety. The methodology which holds most promise to quantify the contributions of N2 fixation to trees is the so-called `15N natural abundance' technique which exploits naturally occurring differences in 15N composition between plant-available N sources in the soil and that of atmospheric N2. In this review we discuss probable explanations for the origin of the small differences in 15N abundance found in different N pools in both natural and man-made ecosystems and utilise previously published information and unpublished data to examine the potential advantages and limitations inherent in the application of the technique to study N2 fixation by woody perennials. Calculation of the proportion of the plant N derived from atmospheric N2 (%Ndfa) using the natural abundance procedure requires that both the 15N natural abundance of the N derived from BNF and that derived from the soil by the target N2-fixing species be determined. It is then assumed that the 15N abundance of the N2-fixing species reflects the relative contributions of the N derived from these two sources. The 15N abundance of the N derived from BNF (B) can vary with micro-symbiont, plant species/provenance and growth stage, all of which create considerable difficulties for its precise evaluation. If the%Ndfa is large and the 15N abundance of the N acquired from other sources is not several 15N units higher or lower than B, then this can be a major source of error. Further difficulties can arise in determining the 15N abundance of the N derived from soil (and plant litter, etc.) by the target plant as it is usually impossible to predict which, if any, non-N2-fixing reference species will obtain N from the same N sources in the same proportions with the same temporal and spatial patterns as the N2-fixing perennial. The compromise solution is to evaluate the 15N abundance of a diverse range of neighbouring non-N2-fixing plants and to compare these values with that of the N2-fixing species and the estimate of B. Only then can it be determined whether the contribution of BNF to the target species can be quantified with any degree of confidence. This review of the literature suggests that while the natural abundance technique appears to provide quantitative measures of BNF in tree plantation and agroforestry systems, particular difficulties may arise which can often limit its application in natural ecosystems.  相似文献   
3.
Biometric analysis for identity verification is becoming a widespread reality. Such implementations necessitate large-scale capture and storage of biometric data, which raises serious issues in terms of data privacy and (if such data is compromised) identity theft. These problems stem from the essential permanence of biometric data, which (unlike secret passwords or physical tokens) cannot be refreshed or reissued if compromised. Our previously presented biometric-hash framework prescribes the integration of external (password or token-derived) randomness with user-specific biometrics, resulting in bitstring outputs with security characteristics (i.e., noninvertibility) comparable to cryptographic ciphers or hashes. The resultant BioHashes are hence cancellable, i.e., straightforwardly revoked and reissued (via refreshed password or reissued token) if compromised. BioHashing furthermore enhances recognition effectiveness, which is explained in this paper as arising from the random multispace quantization (RMQ) of biometric and external random inputs  相似文献   
4.
Under the National Ambient Air Quality Standard (NAAQS) for airborne lead, measurements are conducted by means of a high-volume total suspended particulate matter (Hi-Vol TSP) sampler. In the decade between 1973 and 1983, there were 12 publications that explored the sampling characteristics and effectiveness of the Hi-Vol TSP, yet there persists uncertainty regarding its performance. This article presents an overview of the existing literature on the performance of the Hi-Vol TSP, and identifies the reported sampler effectiveness with respect to four factors: particle size (reported effectiveness of 7%–100%), wind speed (?36% to 100%), sampler orientation (7%–100%), and operational state (107%–140%). Effectiveness of the Hi-Vol TSP was evaluated with a solid, polydisperse aerosol in a controlled wind tunnel setting. Isokinetic samplers were deployed alongside the Hi-Vol TSP to investigate three wind speeds (2, 8, and 24 km h?1), three sampler orientations (0°, 45°, 90°), and two operational states (on, off) for aerosols with aerodynamic diameters from 5 to 35 µm. Results indicate that particle diameter was the largest determining factor of effectiveness followed by wind speed. Orientation of the sampler did not have a significant effect at 2 and 8 km h?1 but did at 24 km h?1. In a passive state, the Hi-Vol TSP was collected between 1% and 7% of available aerosol depending on particle size and wind speed. Results of this research do not invalidate results of previous studies but rather contribute to our overall understanding of the Hi-Vol TSP's size-selective performance. While results generally agreed with previous studies, the Hi-Vol TSP was found to exhibit less dependence on these four factors than previously reported.

© 2017 American Association for Aerosol Research  相似文献   
5.
PURPOSE: We report a retrospective series of 850 patients treated by external irradiation for carcinoma of the eyelid at Institut Curie and we compare our results with other techniques: brachytherapy and surgery. METHODS AND MATERIALS: Eight hundred fifty patients were treated by external radiotherapy for carcinoma of the eyelid. None of these patients have been previously treated. All the patients were classified according to the TNM classification of (UICC). We distinguished five histological types and five clinical groups according to the site of the skin tumor. Three modalities of external radiotherapy were used: contact therapy, conventional radiotherapy, and electrontherapy. We reviewed the clinical files of the 850 patients who went regularly at follow-up visits. RESULTS: We report the 5-year survival results--alive with no evidence of disease: 72%; alive with progression: 2%; died from tumor progression: 0.5%; died from intercurrent disease: 19.5%; and lost to follow-up: 5%. The 5-year local control rate was 97.5%. We observed 45 failures--lymph node, metastatic, and local--and emphasize this last group by presenting the results of treatment of these local failures. We studied the complications of treatment: 2.3% of corneal complications, 2% of cataracts, and 1.4% of serious ocular complications. CONCLUSIONS: Our results concerning local failures and loss of the eye are comparable to those reported for other techniques involving brachytherapy or surgery. Overall, external radiotherapy is a safe and effective treatment, as it ensures a high local control rate and provides perfectly satisfactory functional and esthetic results. It seemed particularly useful to report this series in that few publications are available on this subject that, nevertheless, constitutes a topical issue.  相似文献   
6.
Collaborative work to determine the amino acid, taurine, urea and ammonia contents of a standard mixture of amino acids and of blood plasma from a preruminant and a ruminant calf was carried out at four laboratories to assess the accuracy of the ion-exchange column chromatographic technique. Samples of blood plasma were deproteinised by the organising laboratory and by the collaborating laboratories using their own methods. For the standard amino acid mixture the mean absolute deviation was 0.036 of the true concentration. This compared favourably with results from previous collaborative trials on protein hydrolysates. The mean absolute deviations were 0.192 for preruminant calf blood deproteinised by the organising laboratory and 0.159 for blood deproteinised by the collaborating laboratories. Comparable values for ruminant calf blood were 0.149 and 0.117, respectively. These results were much poorer than those obtained for protein hydrolysates and possible explanations are put forward for these different degrees of precision.  相似文献   
7.
Alwyn S. Tooth  Indrarko Susatijo   《Thin》1983,1(2):121-138
The instability behaviour of thin-walled horizontal cylindrical vessels supported by means of ring girders, or from rigid end plates, is examined experimentally during liquid filling. Selected results from a horizontal test on a large stainless steel horizontal storage vessel are presented to illustrate the way in which thin-walled vessels, of large radius/thickness ratios (300–650), behave during fill.Such results have provided the motivation for some 26 polyester film model cylinder tests. The models cover three different radius/thickness ratios (300, 400 and 500) and a range of length/radius ratios. They were supported at their ends and progressively filled with liquid. In each case the onset of instability was noted. In Part II1 of this paper a theoretical approach is presented and compared with the experimental values in an effort to assess the validity of design methods currently in use.  相似文献   
8.
A review is presented of the gaseous combustion and pyrolysis products evolved from coal, wood and PVC. Information has been collated on the range of products evolved, the temperatures of evolution and the effect of different ambient conditions (e.g. oxidizing of inert conditions). The data for coal have been subdivided into those from which rates of gas evolution have been or can be derived and those from which this is not possible. Probable decomposition routes for PVC and for wood are discussed. Although all three materials have been widely studied, the correlation between the work of different authors in not always good. The data obtained are dependent on the form of the experiment, and there are gaps in the information available, especially information on the rates of evolution of products of products as a function of temperature.  相似文献   
9.
10.
OBJECTIVE: To review the breed, age, gender, clinical and laboratory findings, treatment and outcome of horses with caecal disease presented to a referral centre. DESIGN: Retrospective study of 96 cases. PROCEDURE: The breed, age, and gender of the study population were compared with the corresponding hospital population for the same period. The means (+/- SD) for clinical and laboratory findings were recorded for each caecal disorder. Treatment was categorised as medical or surgical, and outcome was recorded. RESULTS: Caecal diseases included impaction (40% of total cases), rupture associated with concurrent unrelated disease (13%), rupture with parturition (9%), rupture with no associated disease (5%), infarction (11%), torsion (9%), abscess or adhesion (7%), tumour (3%), and miscellaneous conditions (3%). The breed or gender of affected horses did not differ from the hospital population, although horses > 15 years were more frequently represented (P < 0.05). This age group was specifically more predisposed to caecal impaction (P < 0.05), as were Arabian, Morgan, and Appaloosa breeds (P < 0.05). In horses with caecal impaction transrectal examination was the most useful diagnostic procedure; 90% of affected horses treated medically were discharged while horses treated by typhlotomy alone, or typhlotomy and blind end ileocolostomy, had survival rates to discharge of 71% and 86%, respectively. Horses with caecal rupture associated with concurrent un-related disease showed no signs of impending rupture; all were receiving phenylbutazone, all were euthanased, and 50% had caecal ulceration at necropsy. Of horses with caecal rupture with parturition 56% had prior dystocia; in two-thirds the site of rupture was the ileocaecal junction and all were euthanased. Horses with caecal rupture with no associated disease died or were euthanased; rupture was idiopathic. Horses with caecal infarction usually had signs of abdominal pain and abdominal fluid changes consistent with peritonitis; transrectal examination was nonspecific, and typhlectomy was successful in seven of eight horses. Horses with caecal torsion had signs of severe, acute abdominal pain and typhlectomy was successful in three of five horses. Diagnosis of caecal adhesion or abscess was assisted by transrectal palpation in two of seven horses and surgical treatment was successful in two of five horses. A caecal tumour was diagnosed in three horses aged 20 years or older that presented with chronic weight loss. Other caecal diseases were uncommon. CONCLUSION: Caecal disease is uncommon in equids but some specific features of the history and physical findings can alert the veterinarian to the possibility of caecal involvement in horses with gastrointestinal dysfunction. Medical or surgical therapy can be effective in horses where caecal rupture has not occurred.  相似文献   
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