bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of a Single-Server Tandem Queueing System with Setups
Authors: Duenyas Izak , Gupta Diwakar , Olsen Tava Lennon 
Published: November 2008

This paper considers the control of a single-server tandem queueing system with setups. Jobs arrive to the system according to a Poisson process and are produced to order. A single server must perform a number of different operations on each job. There is a setup time for the server to switch between different operations. We assume that there is a holding cost at each operation, which is nondecreasing in operation number (i.e., as value is added to a job, it becomes more expensive to hold). The control problem is to decide which job the server should process at each point in time. We formulate this control problem as a Markov-Decision Process. We partially characterize the optimal policy, develop an exact analysis of exhaustive and gated polling policies, and develop an effective heuristic policy. The results of a simulation study, which tests the performance of the policies considered, are reported. These computational results indicate that our heuristic is effective for a wide variety of cases.
Scheduling with Finite Capacity Output Buffers
Authors: Hall Nicholas G. , Posner Marc E. , Potts Chris N. 
Published: November 2008

In many scheduling problems, a job that completes processing may need to be held in an output buffer until the customer is ready to accept delivery. Buffer capacity is usually assumed to be infinite. We study a number of the best known single machine scheduling problems, under several alternative assumptions about the capacity of the output buffer. Specifically, we allow the buffer capacity to be either zero, fixed, or specified as part of problem input. We also consider situations in which all jobs have the same storage requirement in the buffer, and others where the storage requirement may vary. Further, we consider generalizations where there is a time interval within which a customer accepts delivery without cost to the producer. A classification scheme for these problems is provided. For each problem considered, we provide either an efficient algorithm or a proof that such an algorithm is unlikely to exist. Our results provide a mapping of the computational complexity of these problems which parallels those that are available for classical scheduling problems with infinite buffer capacity.
Managing Stochastic Multiproduct Systems: Model, Measures, and Analysis
Authors: Anupindi Ravi , Tayur Sridhar 
Published: November 2008

We consider a model for managing a single stage that produces multiple items. The production rates are finite, and there are switchover times. The interarrival times and quantities of demands for the items are random, and demand may occur for a set of items. We consider order focussed measures: cost based on response times; service levels based on quoted lead times and Type-1 service. We operate the stage in the following manner: (1) there is a cyclic schedule that determines the sequence of items and the number of times a particular item is produced in a cycle; (2) given a cyclic schedule, production of each item follows a modified base-stock policy or a (s, S) policy. We present a simulation based procedure to obtain good values for the base stock levels or S (for any fixed S − s) for each of the above performance measures. Numerical results indicate that good solutions can be obtained with modest computational effort. We also report on a real world implementation of this model.
Optimal Component Assignment and Board Grouping in Printed Circuit Board Manufacturing
Authors: Hillier Mark S. , Brandeau Margaret L. 
Published: November 2008

We consider operation assignment problems arising from a printed circuit board assembly process. The research was inspired by an application at Hewlett Packard where hundreds of types of printed circuit boards require the insertion of a number of components. The components can be inserted manually or by semiautomated insertion machines. The machines are limited in terms of the number of different component types that they can hold. We investigate how to assign the boards and components to the machines and manual process so as to minimize cost. An optimal solution technique is developed for the single-machine case and for the multiple-machine case where boards are not allowed to be set up on more than one process. In addition, a heuristic is developed which gives near-optimal solutions (within 0.3%) with much less computational effort. Although the problem this paper specifically addresses is that of partially automated PC board assembly, the results apply to a more general set of problems. Other applications include completely automated PC board assembly, flexible manufacturing systems, and general operation assignment problems.
The U.S. Army National Guard's Mobile Training Simulators Location and Routing Problem
Authors: Murty Katta G. , Djang Philipp A. 
Published: November 2008

For training National Guard units, the U.S. Army National Guard will field 21 combat vehicle training simulators called mobile trainers. Each National Guard unit must train at a station that is not farther than a specified maximum travel distance from its armory. We address the problem of finding: • the optimum locations for the home bases for the mobile trainers, • the locations of secondary training sites to which the mobile trainers will travel to provide training, and • the actual routes that the mobile trainers will take to cover all these secondary training sites. The aim is to allocate each National Guard unit to a training site within the maximum travel distance from its armory, while simultaneously minimizing the mobile trainer fleet mileage and the total distance traveled by all units. The problem is too large and complex to solve as a single model. We apply a heuristic decomposition strategy to break the overall problem into manageable stages, developing suitable substitute objective functions for each. This approach led to a solution in which the mobile trainer fleet mileage is 72,850 miles per year: about 70% smaller than the 231,000 miles per year in the original Army's procurement plan. Our solution has been implemented (with minor modifications) by the Army.
Fast Algorithms for Parametric Scheduling Come From Extensions to Parametric Maximum Flow
Authors: McCormick S. Thomas 
Published: November 2008

Chen (1994) develops an attractive variant of the classical problem of preemptively scheduling independent jobs with release dates and due dates. Chen suggests that in practice one can often pay to reduce the processing requirement of a job. This leads to two parametric max flow problems. Serafini (1996) considers scheduling independent jobs with due dates on multiple machines, where jobs can be split among machines so that pieces of a single job can execute in parallel. Minimizing the maximum tardiness again gives a parametric max flow problem. A third problem of this type is deciding how many more games a baseball team can lose part way through a season without being eliminated from finishing first (assuming a best possible distribution of wins and losses by other teams). A fourth such problem is an extended selection problem of Brumelle et al. (1995a), where we want to discount the costs of “tree-structured” tools as little as possible to be able to process all jobs at a profit. It is tempting to try to solve these problems with the parametric push-relabel max flow methods of Gallo et al. (GGT) (1989). However, all these applications appear to violate the conditions necessary to apply GGT. We extend GGT in three ways that allow it to be applied to all four of the above applications. We also consider some other applications where these ideas apply. Our extensions to GGT yield faster algorithms for all these applications.
A Set Partitioning Approach to the Crew Scheduling Problem
Authors: Mingozzi A. , Boschetti M. A. , Ricciardelli S. , Bianco L. 
Published: November 2008

The crew scheduling problem (CSP) appears in many mass transport systems (e.g., airline, bus, and railway industry) and consists of scheduling a number of crews to operate a set of transport tasks satisfying a variety of constraints. This problem is formulated as a set partitioning problem with side constraints (SP), where each column of the SP matrix corresponds to a feasible duty, which is a subset of tasks performed by a crew. We describe a procedure that, without using the SP matrix, computes a lower bound to the CSP by finding a heuristic solution to the dual of the linear relaxation of SP. Such dual solution is obtained by combining a number of different bounding procedures. The dual solution is used to reduce the number of variables in the SP in such a way that the resulting SP problem can be solved by a branch-and-bound algorithm. Computational results are given for problems derived from the literature and involving from 50 to 500 tasks.
On Warehousing Problems
Authors: Prager William 
Published: November 2008

An entrepreneur operates a warehouse of a given capacity for storing a seasonal product. At the beginning of each of a number of consecutive periods (“months”), the product can be bought for storage at a known cost per unit or sold from storage at a known quantity-dependent price per unit. For a given month, the selling price per unit is supposed to have a constant value up to a certain number of units and a lesser constant value for additional units sold. What pattern of buying, storing, and selling should the entrepreneur adopt to maximize his profit? In this paper, a warehousing problem of this kind is shown to be a generalized Hitchcock distribution problem with mixed boundary conditions and non-positive flows along certain routes. This fact suggests a simple procedure for solving problems of this kind. The procedure readily allows the inclusion of storage costs, which were neglected by Charnes and Cooper.
Relationships between serum adiponectin levels versus bone mineral density, bone metabolic markers, and vertebral fractures in type 2 diabetes mellitus
Authors: Kanazawa Ippei , Yamaguchi Toru , Yamamoto Masahiro , Yamauchi Mika , Yano Shozo , Sugimoto Toshitsugu 
Published: November 2008

BackgroundAlthough, adiponectin might be associated with bone metabolism, the relationships between serum adiponectin and bone mineral density (BMD) as well as vertebral fracture in type 2 diabetes are still unclear.Objective and methodsWe investigated the relationships between each of serum total and high molecular weight (HMW) adiponectin versus BMD, bone markers, and the presence of vertebral fractures in a total of 231 men and 170 post-menopausal women with type 2 diabetes.ResultsMultiple regression analysis adjusted for age, duration of diabetes, BMI, serum creatinine, and HbA1c showed that serum total adiponectin was negatively correlated with BMD at the total, lumbar spine, and femoral neck (r=−0.165, P<0.05; r=−0.187, P<0.05; and r=−0.136, P<0.05 respectively) and positively with urinary N-terminal cross-linked telopeptide of type-I collagen in men (r=0.148, P<0.05), and that serum HMW adiponectin was negatively correlated with BMD at the lumbar spine (r=−0.146, P<0.05). Multivariate logistic regression analysis adjusted for the parameters described above showed that total adiponectin was associated with the presence of vertebral fractures in men (odds ratio (OR)=1.396, 95% confidential interval (CI) 1.020–1.911 per s.d. increase, P<0.05), and both total and HMW adiponectin were associated with moderate or severe vertebral fractures (OR=1.709, 95% CI 1.048–2.787 per s.d. increase, P<0.05 and OR=1.810, 95% CI 1.112–2.946 per s.d. increase, P<0.05 respectively), but not in post-menopausal women.ConclusionsSerum adiponectin could be associated with BMD and turnover and clinically useful for assessing the risk of vertebral fractures in type 2 diabetic men.
Gamma knife stereotactic radiosurgery of Nelson syndrome
Authors: Vik-Mo Einar Osland , Øksnes Marianne , Pedersen Paal-Henning , Wentzel-Larsen Tore , Rødahl Eyvind , Thorsen Frits , Schreiner Thomas , Aanderud Sylvi , Lund-Johansen Morten 
Published: November 2008

ObjectiveGamma knife radiosurgery (GKR) can be used as primary or adjuvant therapy for the treatment of an ACTH-producing pituitary tumor after bilateral adrenalectomy, called Nelson syndrome (NS). We have examined the effect of GKR on tumor growth and ACTH-hypersecretion, and characterized the adverse events of this treatment in patients with NS.DesignCross-sectional follow-up study. First, retrospective data pre- and post-GKR were collected. Patients then underwent a predefined survey including radiological, endocrinological, ophthalmological, and neurosurgical evaluation.SubjectsTen patients treated with GKR for NS after previous bilateral adrenalectomy. The mean follow-up was 7 years. No patient was lost to follow-up.ResultsTumor growth was stopped in all patients. The ACTH levels declined in eight patients, and normalized in one patient. There was a significant drop in ACTH levels, with a half-time of 2.8 years. No patient developed visual field defects or any other cranial nerve dysfunction as a result of treatment. Four patients started hormone substitution therapy during the follow-up period. The substitution therapy of three pituitary axes present at GKR treatment could be stopped during the same period. One patient developed a glioblastoma in the left parieto-occipital region 14 years after GKR, far from the field of treatment. As the radiation level was below 1Gy to this area, it is unlikely that the GKR treatment itself induced the malignant tumor.ConclusionIn patients with NS, GKR is an effective adjuvant treatment, carrying relatively few adverse effects. Although the risk of developing a secondary neoplasia after GKR is present, it is probably extremely low.
Presurgical Systemic Treatment of Nonmetastatic Breast Cancer: Facts and Open Questions
Authors: Berruti Alfredo , Brizzi Maria Pia , Generali Daniele , Ardine Mara , Dogliotti Luigi , Bruzzi Paolo , Bottini Alberto 
Published: November 2008

Abstract

Learning Objectives
After completing this course, the reader should be able to: Identify the great advantages of primary systemic therapy from a research perspective and also the problems preventing the recommendation to adopt this treatment modality instead of adjuvant therapy in clinical practice.Define pathological complete response and discuss its clinical significance.Define the concept of a surrogate parameter of treatment efficacy and discriminate it from a prognostic parameter.Summarize the main characteristics and findings of randomized trials of primary systemic therapy in comparison with randomized trials of adjuvant therapy.
CME This article is available for continuing medical education credit at CME.TheOncologist.com
There are several advantages of administering primary systemic therapy (PST) instead of adjuvant therapy in the management of early breast cancer patients: (a) PST allows for a quantifiable evaluation of the sensitivity or resistance of any treated case and (b) the response assessment offers the opportunity to “cross over” to a different regimen for an individual patient, leading to more flexible, “tailored” therapies. Indeed, these advantages are tenable if one assumes that the primary tumor response serves as a surrogate marker of the efficacy of PST in terms of survival. Unfortunately, this has not yet been validated. The data that are actually available show that both clinical complete response (cCR) and pathological (p)CR have prognostic significance. pCR after chemotherapy has a greater prognostic impact than cCR; however, it is frequently observed in a subset of tumors—such as those that are estrogen receptor negative, are human epidermal growth factor receptor positive, and have elevated proliferative activity—but occurs rarely in their human epidermal growth factor receptor-2/neu counterparts. cCR is more sensitive than pCR, but its assessment presents many hindrances. cCR after chemotherapy can predict early on which tumors are destined to undergo pCR, suggesting a role for this endpoint guiding further treatment decisions early on. The pCR rate in small randomized PST studies comparing chemotherapy with chemotherapy plus trastuzumab was able to predict the difference in survival observed in large, randomized adjuvant trials with a similar study design. Conversely pCR cannot predict the outcome benefit of patients undergoing different hormonal therapies.
In conclusion, pCR may be a reliable surrogate endpoint for PST efficacy in a subset of patients undergoing chemotherapy.
The development of visual attention in deaf children in relation to mother's hearing status
Authors: Chasin Joan , Harris Margaret 
Published: November 2008

The development of visual attention in deaf children in relation to mother's hearing status
Patterns of visual attention during free-play in deaf children with deaf (Dd) and hearing mothers (Dh) were compared at 9, 12 and 18 months. Dd children were more likely to look at their mother's face spontaneously than Dh children at all ages although spontaneous looking increased significantly at 18 months for both groups. The proportion of responsive looks declined at 12 months for the Dd group but not until 18 months for the Dh group. Elicited looking was more common in the Dd group and, at 12 months, a greater proportion of these looks were to the mother's face. Overall the results suggest that Dd children show greater sensitivity to the communicative significance of their mother's face in the second year of life.
Interactions of fathers and their children with autism1
Authors: Pisula Ewa 
Published: November 2008

Interactions of fathers and their children with autism1
The aim of the present study was to compare the activity of fathers and their children with autism with those of children with Down syndrome, and normally developing children during the father-child interaction. Participants were 14 children with autism and their fathers, 15 children with Down syndrome and their fathers, and 16 normally developing children and their fathers. The age of subjects was between 3.0 and 6.0 years old. The study consisted of one 15-minute free-play session in the father-child diad, taking place in the experiment room. Differences between the groups of fathers were found in terms of three variables under analysis: frequency of looking at the child, physical contact with the child and suggesting play. Children with autism brought objects to their fathers or pointed out objects and directed their fathers' attention by vocalising less frequently than children with Down syndrome and normally developing children. Moreover, children with autism exhibited the fewest vocalisations combined with looking at the father and exhibited many more behaviours involving running and moving about the room than normally developing children. Self-stimulating behaviours were the most frequent in children with autism, with no differences in that respect found between children with Down syndrome and normally developing children. The analysis of fathers' behaviour demonstrates that fathers of children with developmental disorders focus on observing their children and attempt to keep close contact with them to a larger extent than fathers of normally developing children. The pattern of differences in the activity of fathers of children with autism and children with Down syndrome does not paint a clear picture. In general, fathers from both groups actively sought to maintain contact with their children. Differences in the activity during play between children with autism and the other subjects in the study are consistent with the clinical features of autism.
Importance of adrenergic receptors in prenatally induced cognitive impairment in the domestic chick
Authors: Gibbs Marie E. , Rodricks Candice L. , Hutchinson Dana S. , Summers Roger J. , Miller Suzanne L. 
Published: November 2008

AbstractIn the domestic chick, mild hypoxia (24 h of 14% oxygen) at two stages of embryonic development results in post‐hatch memory deficiencies tested using a discriminated bead avoidance task. The nature of the memory loss depends on the gestational age at which the hypoxia occurs. Hypoxia on embryonic day 10 (E10) of a 21 day incubation results in chicks with no short‐term memory 10 min after training, whereas hypoxia on day 14 (E14) results in chicks with good labile memory 30 min after training but no consolidation of memory into permanent storage (120 min). Hypoxia at E14 is associated with increased plasma levels of noradrenaline and therefore we suggest that altered catecholamine exposure within the brain contributes to cognitive problems by modifying the responsiveness of brain β‐adrenoceptors. In ovo administration of noradrenaline, or the β2‐adrenoceptor agonist formoterol, at E14 had the same effect on memory consolidation as hypoxia. Following hypoxia at E14, memory could be rescued after training by central injection of a β3‐adrenoceptor agonist, but not by a β2‐adrenoceptor agonist. The differences in the responsiveness of memory processing to β2‐adrenoceptor agonists suggests alterations to the receptors or downstream of the receptor activation. However, both types of β‐adrenoceptor agonists rescued memory in E10 treated chicks implying that at this age hypoxia does not affect the receptors. In summary, hypoxia or increased levels of stress hormones during incubation alters β‐adrenoceptor responsiveness; the outcome of the insult depends upon the cellular developmental processes at a given embryonic stage.
A proposed framework for strategy implementation in the Indian context
Authors: Kazmi Azhar 
Published: November 2008

PurposeThe purpose of this paper is to review the extant literature on strategy implementation with a view to highlight the pitfalls and use these to build a new framework that could be more relevant to the conditions existing in the Indian context.Design/methodology/approachThis paper provides a review of strategy implementation frameworks available both in strategy literature and in strategy texts to identify the main pitfalls in effective strategy implementation and then proceeds to propose a framework that could be more suitable to the Indian context. This proposed framework is then applied and described in the context of a case study of the Reliance group of companies of India.FindingsThe proposed strategy implementation framework covers many of the aspects hitherto neglected in the frameworks suggested by researchers and authors more attuned to the Western context. Two of the major issues in strategy implementation not covered in the existing framework are of procedural and project implementation that may be considered as relevant in the Indian context.Research limitations/implicationsThe proposed framework is demonstrated in the case of only one Indian company. The efficacy of the framework need to be further investigated.Practical implicationsApplication of the proposed framework is likely to result in a more comprehensive coverage of the vital issues in strategy implementation that are expected to do away with the pitfalls that are commonly experienced in the process of strategy implementation.Originality/valueThe paper proposes a new framework of strategy implementation based on the unique requirements of the Indian context.