Telecommunications Management

DISASTER RECOVERY PLANNING FOR TELECOMMUNICATIONS by Leo A. Wrobel (Boston: Artech House, 1990—price not given, ISBN 0-89006-460-1,112 pp.)

LONG DISTANCE SERVICES: A BUYER'S GUIDE by Daniel D. Briere (Boston: Artech House, 1990—price not given, ISBN 0-89006-439-3,293 pp.)

ADVANCES IN TELECOMMUNICATIONS MANAGEMENT edited by Jagdish Sheth and Garly Frazier (Greenwich, CT: JAI Press, 1990—$63.50 each, ISBN as listed below)

MANAGING THE R&D/MARKETING INTERFACE FOR PRODUCT SUCCESS: THE TELECOMMUNICATIONS FOCUS edited by Massoud Saghafi and Ashok K. Gupta (1990—ISBN 1-55938-144-2,218 pp.)

PURCHASING IN THE 1990S: THE EVOLUTION OF PROCUREMENT IN THE TELECOMMUNICATIONS INDUSTRY edited by Wesley J. Johnston (1990—ISBN 1-55938-145-0,257 pp.)     

Eigentaste: A Constant Time Collaborative Filtering Algorithm

Eigentaste is a collaborative filtering algorithm that uses universal queries to elicit real-valued user ratings on a common set of items and applies principal component analysis (PCA) to the resulting dense subset of the ratings matrix. PCA facilitates dimensionality reduction for offline clustering of users and rapid computation of recommendations. For a database of n users, standard nearest-neighbor techniques require O(n) processing time to compute recommendations, whereas Eigentaste requires O(1) (constant) time. We compare Eigentaste to alternative algorithms using data from Jester, an online joke recommending system.Jester has collected approximately 2,500,000 ratings from 57,000 users. We use the Normalized Mean Absolute Error (NMAE) measure to compare performance of different algorithms. In the Appendix we use Uniform and Normal distribution models to derive analytic estimates of NMAE when predictions are random. On the Jester dataset, Eigentaste computes recommendations two orders of magnitude faster with no loss of accuracy. Jester is online at: http://eigentaste.berkeley.edu     

Prevalence of Vitamin D Deficiency in a Pediatric Hospital of Eastern India

Vitamin D deficiency is highly prevalent in Indian children of northern, western and southern states. Serum 25 hydroxy cholecalferol (ng/ml) was analyzed in 310 children and adolescents of pediatric hospital of Kolkata, India. Serum calcium (mg/dl), phosphorous (mg/dl) and alkaline phosphatase (IU/L) data was obtained. Median 25(OH)D was 19 ng/ml. 19.2 % of population had serum 25(OH)D < 10 ng/ml (severe deficiency), 52.9 % had <20 ng/ml (deficiency), 24.5 % had 20–29 ng/ml (insufficiency) and 22.6 % had >30 ng/ml (optimum). Deficiency was highest in adolescents (86.1 %), followed by school children (61.0 %), lowest in pre-school children (41.6 %). 25(OH)D concentrations was lowest in winters (P = 0.002) and spring (P = 0.03) compared to summer. There was no correlation with calcium (P = 0.99), phosphorous (P = 0.23) and ALP (P = 0.63). There is high prevalence of vitamin D deficiency in children and adolescents of eastern India. Prevalence was lower in younger subjects. 25(OH)D did not correlate with bone mineral markers.     

Interpreting HbA1c in Presence of Deficiency Anemias

HbA1c is used extensively for the diagnosis and management of diabetes mellitus. It constitutes 80% of glycated HbA1(Glycated haemoglobin(GHb)A), and depends upon blood glucose and RBC life span. RBC life span varies with anemia, leading to a consequent alteration in the HbA1c value irrespective of the circulating blood glucose concentration. But to the best of our knowledge no Hb cut offs have been derived for appropriate interpretation of HbA1c. The prevalence of anemia in Indian population is nearly 40% as per its definition by WHO—Hb < 12 g/dL in females and < 13 g/dL in males—with most cases attributable to nutritional deficiencies. Hence, we aimed to identify Hb cut-off for accurate interpretation of HbA_1c in presence of deficiency anemias. Partial correlation between random blood glucose (RBG) and HbA_1c was studied in 1312 subjects, 470 of whom had deficiency-related anemia]. The data was adjusted for age, sex and Hb. Partial correlation between RBG and HbA1c was highly significant (p < 0.0001) till Hb of 8.1 gm/dL. Significance reduced to p = 0.003 and p = 0.006 as the cut off of Hb reduced to 7.1 gm/dL and 5.0 gm/dL, respectively, but was not lost. Hence, caution in interpretation of HbA_1c is not required till an Hb of 5 g/dL.     

Learning,Training, and Performance Timeline: A Walk Through History

Does your professional tool bag include the well‐known ideas, models, and practices that training and performance improvement professionals use? This article organizes the advent of essential tools using the Learning, Training, and Performance Timeline, describes the major patterns that developed during historical periods, and explores relevant practical and scholarly uses for the Timeline. Resources are provided for those who have further inquiries about the historical background of training and performance improvement.     

Cartap and carbofuran induced alterations in serum lipid profile of Wistar rats

Wistar rats of 6–8 weeks in age weighing between 120–150 g were exposed to the fixed doses of each of the carbamate pesticides such as cartap (50% LD₅₀) and carbofuran (50% LD₅₀) as well as a combination of these two with 25% LD₅₀ of each for one week. The effect of treatments was studied in terms of serum lipid parameters such as high-density lipoprotein, total cholesterol, triglyceride, low-density lipoprotein and very low-density lipoprotein. Treatment with individual doses of carbofuran (50% LD₅₀) and cartap (50 % LD₅₀) caused significant alterations in the levels of serum lipid parameters. The pesticides treatment resulted in marked decrease in the level of serum high-density lipoprotein where as that of other lipids got significantly elevated. Further, the rats exhibited relatively higher impact of pesticides when treated with the compounds in combination (25 % LD₅₀ of each). The results indicated that these compounds when used together may exert enhanced effect on the levels of serum lipids in rat.     

Effect of a Mindful Breathing Intervention on Community College Students’ Writing Apprehension and Writing Performance

Mindful breathing has been linked to changes in physiology, but we took the practice further by examining whether a mindfulness breathing intervention, a three-minute breathing exercise marked by focused attention on the sensations of breath, affected writing anxiety, and writing performance measures. In addition, we examined mindful breathing as an intervention for community college students—some of the most at risk and underprepared students in higher education in the United States. We compared Daly Miller Writing Apprehension surveys and narrative writing samples from 277 students enrolled in a freshman composition course at a southeastern community college, half of the class sections were randomly assigned to practice a mindful-breathing technique at the beginning of class sessions. Students in the class sections that practiced mindful-breathing group experienced a statistically significant decrease in writing apprehension and mechanical error scores from pre- to post-test when compared to students in the comparison class sections.     

On the approximate discrete KLT of fractional Brownian motion and applications

This paper establishes connection between discrete cosine transform (DCT) and the discrete-time fractional Brownian motion process (dfBm). It is proved that the eigenvectors of the auto-covariance matrix of a dfBm can be approximated by DCT basis vectors in the asymptotic sense. This shows that DCT basis acts as discrete Karhunen–Loève transform (DKLT) for these processes in the approximate sense. Analytic perturbation theory of linear operators is used to prove this result. This result will be of great practical significance in applications where one is looking for an appropriate basis to work with signals that can perhaps be modeled as belonging to fBm processes. The utility of the proposed work has been illustrated with two real-life data (a) on compressive sampling based reconstruction of financial time-series and (b) in denoising gravitational wave event GW150914 data obtained from a binary black hole merger.