An adaptive Huber method for weakly singular second kind Volterra integral equations with non-linear dependencies between unknowns and their integrals

Numerical methods for weakly singular Volterra integral equations with non-linear dependencies between unknowns and their integrals, are almost non-existent in the literature. In the present work an adaptive Huber method for such equations is proposed, by extending the method previously formulated for the first kind Abel equations. The method is tested on example integral equations involving integrals with kernels K(t, τ) = (t ? τ)^?1/2, K(t, τ) = exp[?λ(t ? τ)](t ? τ)^?1/2 (where λ > 0), and K(t, τ) = 1. By controlling estimated local discretisation errors, the integral equation can be solved adaptively on a discrete grid of nodes in the independent variable domain, in a step-by-step fashion. The practical accuracy order is close to 2. The accuracy can be varied by varying the prescribed local error tolerance parameter tol, although the actual errors tend to be larger than tol. Approximations to off-nodal solution values can also be computed, with a comparable accuracy. The method appears numerically stable when partial derivatives, of the non-linear function representing the equation, with respect to the unknown and its integral(s), are of the same sign. The stability of the method in the opposite case may be debated.     

ERP in the Internet Economy

This paper discusses the future of Enterprise Resource Planning and (ERP) in the Internet Economy. In the Internet Economy, ERP as a distinct entity is giving way to a much broader value proposition that effectively fuses different forms of business applications and services. Back-office and front-office applications within an enterprise will come together, along with applications and services for value-chain collaboration between business partners.     

Socioeconomic Status and Insomnia.

This investigation compared the likelihood of insomnia and insomnia-related health consequences among individuals of different socioeconomic status. A random-digit dialing procedure was used to recruit at least 50 men and 50 women in each age decade from 20 to 80 + years old. Participants completed 2 weeks of sleep diaries as well as questionnaires related to fatigue, sleepiness, and psychological distress. Socioeconomic status was measured by education status assessed at 3 different levels: individual, household, and community. Results indicated that individuals of lower individual and household education were significantly more likely to experience insomnia even after researchers accounted for ethnicity, gender, and age. Additionally, individuals with fewer years of education, particularly those who had dropped out of high school, experienced greater subjective impairment because of their insomnia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of Advanced TCP Stacks on Fast Long-Distance Production Networks

With the growing needs of data intensive science, such as high energy physics, and the need to share data between multiple remote computer and data centers worldwide, the necessity for high network performance to replicate large volumes (TBytes) of data between remote sites in Europe, Japan and the U.S. is imperative. Currently, most production bulk-data replication on the network utilizes multiple parallel standard (Reno based) TCP streams. Optimizing the window sizes and number of parallel stream is time consuming, complex, and varies (in some cases hour by hour) depending on network configurations and loads. We therefore evaluated new advanced TCP stacks that do not require multiple parallel streams while giving good performances on high speed long-distance network paths. In this paper, we report measurements made on real production networks with various TCP implementations on paths with different Round Trip Times (RTT) using both optimal and sub-optimal window sizes.We compared the New Reno TCP with the following stacks: HS-TCP, Fast TCP, S-TCP, HSTCP-LP, H-TCP and Bic-TCP. The analysis will compare and report on the stacks in terms of achievable throughput, impact on RTT, intra- and inter-protocol fairness, stability, as well as the impact of reverse traffic.We also report on some tentative results from tests made on unloaded 10 Gbps paths during SuperComputing 2003.     

Comparison of test protocols for the standard room/corner test

As part of international efforts to evaluate alternative reaction‐to‐fire tests, several series of room/corner tests have been conducted. Materials tested were mostly different wood products but included gypsum board and a few foam plastics. This is a review of the overall results of related studies in which the different test protocols for the standard room/corner test were used. Differences in the test protocols involved two options for the ignition burner scenario and whether or not the ceiling was also lined with the test materials. The test materials were placed on three walls of the room in all the tests. The two burner scenarios were (1) 40 kW for 300 s followed by 160 kW for 300 s and (2) 100 kW for 600 s and 300 kW for 600 s. The 40 and 160 kW burner scenario without the ceiling lined did not provide a severe enough test for flashover to occur with fire‐retardant‐treated materials. Use of the 100 and 300 kW burner scenario without lining the ceiling provided the ability to differentiate between wood products with ASTM E 84 flame spread indexes of 70 to 125 and those with higher flame spread indexes. Lining the ceiling with test material creates a more severe test.     

Testing the Value of Checklists in Code Inspections

Checklists are an important part of code and design inspections. Ideally, they aim to increase the number of faults found per inspection hour by highlighting known areas of previous failure. In practice, although some researchers have quantified checklists' benefits, the conclusions' statistical robustness hasn't been as well represented. The author subjects checklists' effectiveness to formal statistical testing, using data from 308 inspections by industrial engineers over a three-year period. The results showed no evidence that checklists significantly improved these inspections. Further analysis revealed that individual inspection performance varied by a factor of 10 in terms of faults found per unit time, and individuals found on average about 53 percent of the faults. Two-person teams found on average 76 percent of the faults.     

The relationship between student personality characteristics, teacher ratings, and student achievement.

In Study 1, 388 undergraduates (a) rated themselves on the Adjective Check List (ACL), (b) viewed a videotape that varied in instructor expressiveness and lecture content, (c) evaluated the videotaped instructor and a test on the lecture, and (d) completed the ACL for the instructor. In Study 2, 87 Ss were also exposed to 2 videotaped lectures given 1 wk apart. In Study 3, 108 Ss completed the ACL for themselves and their instructors, evaluated their instructor's teaching, and completed a test on common course material. No meaningful or consistent relationship between ratings and student personality characteristics appeared to exist. Personality characteristics of instructors were related to teacher effectiveness ratings. Ratings predicted teacher-produced achievement equally well for classes that differed in the personality characteristics of the students enrolled. Teacher effects on ratings appeared significantly greater than teacher effects on achievement. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Educational seduction: The effect of instructor expressiveness and lecture content on student ratings and achievement.

Previous "educational seduction" research (D. H. Naftulin et al, 1973; J. E. Ware and R. G. Williams, 1975, 1977; Williams and Ware, 1976, 1977) suggests that teacher differences in expressiveness controlled the degree to which lecture content affected student ratings differently from student achievement. The present experiment with 245 university students attempted to replicate statistically this Expressiveness?×?Content?×?Measures interaction in a factorial design which investigated 4 simulated classes. The interaction was found for the high-incentive/no-study-opportunity class and the high-incentive/study-opportunity class, which most resembles typical classes, but not for the low-incentive/study-opportunity class or the low-incentive/no-study-opportunity class, which most resembles educational seduction research. In only the high-incentive/no-study-opportunity class did probes of the interaction replicate education seduction research in which content affected ratings and achievement similarly only for low expressiveness. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)