Integrated Inventory Control and Facility Location Decisions in a Multi-Echelon Supply Chain Network with Hubs

This paper develops mathematical models to coordinate facility location and inventory control for a four-echelon supply chain network consisting of multiple suppliers, warehouses, hubs and retailers. The hubs help in reducing transportation costs by consolidating products from multiple warehouses and directing the larger shipments to the retailer. The integrated models studied in this paper simultaneously determines three types of decisions: (i) facility location—the number and location of warehouses and hubs, (ii) allocation—assignment of suppliers to located warehouses and retailers to located warehouses via the location hubs, and (iii) inventory control decisions at each located warehouse. The goal is to minimize the facility location, transportation and the inventory costs. A mixed integer nonlinear programming formulation is first presented. The nonlinear integer programming formulation is then transformed into a conic mixed integer program and a novel and compact conic mixed integer programming formulation. Computational runs are conducted using commercial solvers to compare the performance of the different formulations. The compact conic mixed integer programming formulation was found to significantly outperform the other formulations by achieving significant computational savings. The results demonstrate that large scale instances of certain multi-echelon supply chain network design problems can be solved using commercial solvers through intelligent reformulation of the model.     

A systematic literature review on the applications of Bayesian networks to predict software quality

Bayesian networks (BN) have been used for decision making in software engineering for many years. In other fields such as bioinformatics, BNs are rigorously evaluated in terms of the techniques that are used to build the network structure and to learn the parameters. We extend our prior mapping study to investigate the extent to which contextual and methodological details regarding BN construction are reported in the studies. We conduct a systematic literature review on the applications of BNs to predict software quality. We focus on more detailed questions regarding (1) dataset characteristics, (2) techniques used for parameter learning, (3) techniques used for structure learning, (4) use of tools, and (5) model validation techniques. Results on ten primary studies show that BNs are mostly built based on expert knowledge, i.e. structure and prior distributions are defined by experts, whereas authors benefit from BN tools and quantitative data to validate their models. In most of the papers, authors do not clearly explain their justification for choosing a specific technique, and they do not compare their proposed BNs with other machine learning approaches. There is also a lack of consensus on the performance measures to validate the proposed BNs. Compared to other domains, the use of BNs is still very limited and current publications do not report enough details to replicate the studies. We propose a framework that provides a set of guidelines for reporting the essential contextual and methodological details of BNs. We believe such a framework would be useful to replicate and extend the work on BNs.     

Altering the brain circuits for reading through intervention: A magnetic source imaging study.

Intervention-related changes in spatiotemporal profiles of regional brain activation were examined by whole-head magnetoencephalography in 15 children with severe reading difficulties who had failed to show adequate progress to quality reading instruction during Grade 1. Intensive intervention initially focused on phonological decoding skills (for 8 weeks) and, during the subsequent 8 weeks, on rapid word recognition ability. Clinically significant improvement in reading skills was noted in 8 children who showed "normalizing" changes in their spatiotemporal profiles of regional brain activity (increased duration of activity in the left temporoparietal region and a shift in the relative timing of activity in temporoparietal and inferior frontal regions). Seven children who demonstrated "compensatory" changes in brain activity (increased duration of activity in the right temporoparietal region and frontal areas, bilaterally) did not show adequate response to intervention. Nonimpaired readers did not show systematic changes in brain activity across visits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sociocultural change and adolescents' perceptions of parent behavior.

Administered the Children's Report of Parent Behavior Inventory (CRPBI) and an SES scale to 1,949 13–18 yr olds from 2 cities in India and to 364 age-matched Ss from 1 city in Canada. Indian Ss were designated as traditional or transitional according to the values they were taught (traditional Indian vs modern Western); Canadian Ss were designated as modern. Factor analyses of CRPBI scales revealed 3 replicable factors: Acceptance, Firm Control (FC), and Psychological Control (PC). ANOVAs were used to test the effects of culture, sex, age, and SES on the 3 CRPBI factors. Younger Ss consistently reported more PC and FC than did older ones. Modern Ss reported the most FC, and traditional Ss reported the most PC. Even though higher SES correlated with lower PC and FC, statistical SES control did not attenuate the strong cultural differences for PC. Results suggest considerable congruence between demands and parental socialization practices. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of hepatitis B surface antigen in pregnant women attending a public hospital for delivery: implication for vaccination strategy in Bangladesh

Routine antenatal hepatitis B surface antigen (HBsAg) screening and immunization of risk babies is very effective in preventing perinatal transmission of hepatitis B virus (HBV). We studied 1,800 parturients attending a public hospital to assess the rationale for such vaccination in Bangladesh. In one in every 29 deliveries (63 of 1,800 or 3.5%), the mother was found to be HBsAg positive. All were asymptomatic and many (41 of 63 or 65%) without risk factors would remain undetected if HBsAg screening were performed on selected groups. Most of the HBsAg-positive mothers (54 of 63 or 85.7%) were found to be chronic carriers and 30.2% (19 of 63) were also hepatitis B e antigen (HBeAg) positive, indicating high infectivity. Although 23 cord blood were positive for HBsAg or HBeAg, none were positive for IgM antibody to hepatitis B core antigen (IgM anti-HBc), suggesting transplacental transmission of the antigens rather than intrauterine infection. These findings are discussed in relation to the cost-effectiveness of routine prenatal screening and immunization of risk babies compared with universal infant immunization.     

Review of Research with the locus of control construct, vol. 3: Extensions and limitations.

Reviews the book, Research with the locus of control construct, vol. 3: Extensions and limitations edited by Herbert M. Lefcourt (1984). Herbert Lefcourt's third edited volume on the topic of research with the locus of control construct is directed to discussions of extensions and limitations of the construct. It is a very timely book, and therefore of interest to researchers on the locus of control (LOC). In Part I, comprehensive reviews are presented in three areas: work and retirement, psychophysiology, and cross-cultural researches. In Part II, two chapters describe the limitations and suggest alternatives. The five chapters are extensive and critical, as well as constructive in presenting ideas and models for future research. The editor and the authors have done an excellent job. As a reference source the book eminently meets the needs of researchers in the area. The editor has provided a succinct introduction and epilogue, which are very helpful in orienting the reader and maintaining a balanced view of the appropriate uses of the concept. The editor and authors of the book are to be congratulated for a thorough, provocative, and balanced outlook presented in this volume. I recommend the book highly. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A contextual approach towards more accurate duplicate bug report detection and ranking

The issue-tracking systems used by software projects contain issues, bugs, or tickets written by a wide variety of bug reporters, with different levels of training and knowledge about the system under development. Typically, reporters lack the skills and/or time to search the issue-tracking system for similar issues already reported. As a result, many reports end up referring to the same issue, which effectively makes the bug-report triaging process time consuming and error prone. Many researchers have approached the bug-deduplication problem using off-the-shelf information-retrieval (IR) tools. In this work, we extend the state of the art by investigating how contextual information about software-quality attributes, software-architecture terms, and system-development topics can be exploited to improve bug deduplication. We demonstrate the effectiveness of our contextual bug-deduplication method at ranking duplicates on the bug repositories of the Android, Eclipse, Mozilla, and OpenOffice software systems. Based on this experience, we conclude that taking into account domain-specific context can improve IR methods for bug deduplication.     

Effects of end‐stage renal disease and dialysis modalities on blood ammonia level

Introduction: Uremia results in a characteristic breath odor (uremic fetor) which is largely due to its high ammonia content. Earlier studies have shown a strong correlation between breath ammonia and blood urea levels and a 10‐fold reduction in breath ammonia after hemodialysis in patients with chronic kidney disease. Potential sources of breath ammonia include: (i) local ammonia production from hydrolysis of urea in the oropharyngeal and respiratory tracts by bacterial flora, and (ii) release of circulating blood ammonia by the lungs. While the effects of uremia and hemodialysis on breath ammonia are well known their effects on blood ammonia are unknown and were explored here. Methods: Blood samples were obtained from 23 hemodialysis patients (immediately before and after dialysis), 14 peritoneal dialysis patients, and 10 healthy controls. Blood levels of ammonia, creatinine, urea, and electrolytes were measured. Findings: No significant difference was found in baseline blood ammonia between hemodialysis, peritoneal dialysis and control groups. Hemodialysis procedure led to a significant reduction in urea concentration (P < 0.001) which was paradoxically accompanied by a modest but significant (P < 0.05) rise in blood ammonia level in 10 of the 23 patients studied. Change in blood ammonia pre‐ and post‐hemodialysis correlated with change in serum bicarbonate levels (r = 0.61, P < 0.01). On subgroup analysis of patients who had a rise in blood ammonia levels after dialysis, there was a strong correlation with drop in mean arterial pressure (r = 0.88, P < 0.01). The nadir intradialytic systolic blood pressure trended lower in the hemodialysis patients who had a rise in blood ammonia compared to the patients who manifested a fall in blood ammonia (124 ± 8 vs. 136 ± 6 mmHg respectively, P = 0.27). Discussion: Fall in blood urea following hemodialysis in ESRD patients was paradoxically accompanied by a modest rise in blood ammonia levels in 43% of the patients studied, contrasting prior reported effects of hemodialysis on breath ammonia. In this subgroup of patients, changes in blood ammonia during hemodialysis correlated with rise in blood bicarbonate and fall in mean arterial blood pressure.