bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reducing vendor delivery uncertainties in a JIT environment
Authors: Hill Arthur V. , Vollmann Thomas E. 
Published: October 2002

AbstractJust‐in‐time (JIT) manufacturing systems have found wide acceptance in the automotive industry as well as in other industries such as electronic assembly. One of the key features of JIT systems is frequent reliable deliveries from local vendors.This article considers two major points related to managing inbound transportation from these local vendors. The first point is that vendor delivery uncertainties can be reduced if the JIT manufacturer takes over the responsibility for inbound logistics from all JIT vendors. In other words, we are suggesting that the manufacturing firm (vendee) pick up raw materials and purchased parts from its vendors rather than having the vendors deliver. The second major point is that a simple economic analysis and a computer‐based decision support system (like that we propose in this article) could be used to help schedule the JIT pickups.The article begins with a description of why deliveries are critical in the JIT environment and why vendee pickup from local vendors can be a better alternative than vendor delivery. When a manufacturer manages its own inbound local deliveries it benefits from more timely information on upsets, reduced transportation costs, reduced transaction costs, and most importantly, reduced uncertainty in deliveries.We then turn to a model for how to schedule JIT pickups. This model addresses the following “JIT Vendor Pickup Problem”: For a given number of vehicles with limited capacity, find a one‐week JIT vendor pickup schedule that will minimize the total incremental carrying, travel, and pickup costs subject to the constraint that the vendee does not run out of any item from any vendor.In the above problem definition, the demand rates for all items are assumed to be constant over the short term. This model can be imbedded in a computer‐based decision support system to facilitate the daily scheduling of the pickups from the vendors.In the conclusion, we deal with the expected benefits to the vendee for managing its own incoming JIT pickups and then propose a model that could be used to implement this concept.
Maximizing the net present value of a project subject to materials and capital constraints
Authors: Smith‐Daniels Dwight E. , Smith‐Daniels Vicki L. 
Published: October 2002

AbstractLarge projects in a variety of industries must be scheduled subject to constraints on capital availability with the objective of maximizing their net present value. The effects of capital and materials costs and constraints have been discussed separately in the project management literature, but they have yet to be treated in an integrated fashion. A framework summarizing the previous research on resource constrained project scheduling is presented in this article and the limited role of monetary objectives in the previous research is illustrated. A new approach to the project scheduling problem is presented where the net present value of a project is maximized subject to capital and material constraints. The major benefit of this approach is that it allows managers to optimize the monetary objectives for a project.A series of examples illustrates the necessity of considering materials costs and constraints in project management. The inclusion of materials management factors in developing a project schedule is shown to lead to lower total project costs. It is demonstrated that the failure to consider materials in the initial planning of a project may lead to either unprojected delays in a project, higher costs, or both.Continued research on this problem is needed in a number of areas. Due to the computational complexity and importance of this problem in practice, it is necessary to develop heuristic approaches to derive project schedules. Future research should compare the results for the existing approaches that minimize project duration to those with monetary objective functions to determine the magnitude of the monetary difference between the former and the latter. Finally, the approach considered in this article should be extended to the multiproject environments where it is necessary to make capital allocation decisions among competing projects.
Operations strategy: A literature review
Authors: Anderson John C. , Cleveland Gary , Schroeder Roger G. 
Published: October 2002

AbstractCompetitive pressures on American business have created the need for improved understanding and practice of operations strategy. Over the past 20 years some 80 articles and several books have been written on the subject. These writings, while diverse in nature and placement, serve to shape what we know about operations strategy and the opportunities for improved practice and meaningful research.This paper examines an underlying argument that exists within the literature that proper strategic positioning or aligning of operations capabilities can significantly impact competitive strength and business performance of an organization. The discussion is organized around four related premises: (1) that there exists a strategic, as opposed to a tactical, view of operations, (2) that there must be some synergistic process of integrating business and operations strategic issues, (3) that there are operations decision or policy areas which demonstrate strategic opportunities, and (4) that conceptual structures exist by which to target and focus operations strategy.The paper concludes that the literature and emerging research support each of these premises to varying degrees. The authors believe that further understanding of these premises could be benefited by more careful and consistent definition of operations strategy concepts and terminology, by more attention being placed on the content and process of operations strategy, by more empirical study, and finally by more emphasis being placed on service operations strategy.
A note on workload‐dependent due date assignment rules
Authors: Ragatz Gary L. 
Published: October 2002

AbstractFor many production systems, delivery performance relative to promised job due dates is a critical evaluation criterion. Delivery performance is affected by the way in which work is dispatched on the shop floor, and also by the way the job due dates are assigned to begin with. This pape shows how information regarding congestion levels on the shop floor can be used to assign due dates to arriving jobs in such a way that the mean tardiness of jobs is decreased without increasing the average length of the promised delivery lead times.Baker and Bertrand suggested a modification of the Total Work (TWK) rule for assigning job due dates which adjusts the job flow allowance according to the level of congestion in the shop. Their method gives longer flow allowances to jobs which arrive when the system is congested. Although their modified TWK rule results in lower mean tardiness in many settings, it also generally results in a higher proportion of jobs tardy.This paper presents an alternative modification of the TWK rule which, in most cases, provides mean tardiness as low as or lower than Baker and Bertrand's rule and also results in a lower proportion of jobs tardy. The alternative rule suggested here still results in higher proportion of tardy jobs than the non‐workload adjusted rule in most settings, but suggestions are made for how this problem might be addressed.
Lasting improvements in manufacturing performance: In search of a new theory
Authors: Ferdows Kasra , De Meyer Arnoud 
Published: October 2002

AbstractIs there a way to avoid trading off one capability for another in manufacturing? The prevailing wisdom says no. But some manufacturers seem to have been able to defy that: compared to their competitors, they have better quality, are more dependable, respond faster to changing market conditions and in spite of all that, achieve lower costs. How can this be explained?Our aim here is to provide an explanation. We contend that the nature of the trade‐offs among manufacturing capabilities is more complex than has been assumed. Depending on the approach taken for developing each capability, the nature of the trade‐offs change. In certain cases not only can trade‐offs be avoided altogether, but in fact one capability would enhance another. They become cumulative. Moreover, when a capability is developed in this way, it is likely to be more lasting and less fragile than if it were developed at the expense of other capabilities.We go on to suggest a model which shows how this can be done: To build cumulative and lasting manufacturing capability, management attention and resources should go first toward enhancing quality, then—while the efforts to enhance quality are further expanded—attention should be paid to improve also the dependability of the production system, then—and again while efforts on the previous two are further enhanced—production flexibility (or reaction speed) should also be improved, and finally, while all these efforts are further enlarged, direct attention can be paid to cost efficiency. We use data from 1988 European Manufacturing Futures Survey (167 respondents) to test and illustrate our model.While we cannot “prove” our model, nevertheless, we believe there is enough evidence for a critical reexamination of traditional managerial approaches for improving manufacturing performance. For example, except for the cases when there are obvious slacks in the production system, the belief that costs can come down quickly and lastingly needs to be questioned. Lasting cost efficiency in production can be achieved only through improvements in other capabilities.
An analysis of customer satisfaction with waiting times in a two‐stage service process
Authors: Davis Mark M. , Maggard Michael J. 
Published: October 2002

AbstractA purely operational approach to providing customer service measures the speed of the service in terms of how long the customer actually waits prior to being served. A more appropriate method. perhaps, is to deal directly with the issue of customer service by measuring customer satisfaction with the wait. In this paper a model is developed which integrates the marketing perspective of customer satisfaction and the operations management perspective of customer waiting time. With this model, the goal of the service manager is to provide an acceptable level of customer satisfaction in lieu of a maximum acceptable average waiting time, which is the current practice. This new approach to defining customer service raises several interesting managerial issues in the design and staffing of a two‐stage (or, for that matter, a multi‐stage) process. For example, is a customer equally satisfied waiting the same amount of time before each stage in the process? If not, what type of strategy does the service manager employ in assigning workers to each of the stages? In order to address these issues, a major portion of this paper focuses on the definition and measurement of customer satisfaction. The application of the model to a real world situation is illustrated using empirical data collected in a two‐stage fast food operation. The results indicate that the speedy acknowledgement of customer arrivals into the system, that is, the prompt taking of customer orders, is more important to the customers than is the time waiting for their orders to be processed. In other words, a customer's wait prior to entering the first stage of the system impacts on customer satisfaction much more than the wait prior to entering stage two. The conclusion from this analysis is that in a sequential, multi‐stage process, management should design and staff the system so that the shortest wait for the customer occurs prior to the first stage.
Enhancing the customer contact model
Authors: Mersha Tigineh 
Published: October 2002

AbstractMost services are provided in the presence of the customer. In most service operations, the customer is not only present but also directly participates in the service delivery process. Such encounters with the service system and the customer's involvement in the service production process have important implications for operations efficiency and effectiveness. Thus, the nature and extent of contact between the customer and the service system should be carefully evaluated in designing service facilities.One approach that has been considered a useful conceptual tool for aiding operations managers in their service design decisions is the customer contact model (CCM). This model classifies service systems into “high contact,” “low contact” and “mixed” services based on the extent of contact between the customer and the service facility. Recently, however, this model's effectiveness as a service management tool has been challenged. CCM has been criticized for failing to sufficiently distinguish between service systems that involve high interaction and customization and those that primarily provide accommodation. The model's capability to assess a service facility's potential efficiency has also been questioned.This paper reevaluates CCM in view of the recent concerns raised about it and offers some extensions which improve the model's performance. It proposes a broadened definition of “customer contact” and differentiates between “active” and “passive” contact. Based on these distinctions, it presents a revised approach for classifying services and for assessing the potential efficiency of service facilities. The extensions provided in this paper would help overcome many of CCM's shortcomings and thus enhance its potential as a viable tool for managing service operations. Therefore, this study, while recognizing the valid criticisms leveled at CCM, asserts that the customer contact concept still provides a useful framework for understanding, designing and controlling service systems.
Mass production of basal bodies in paraspermiogenesis of Tubificinae (Annelida, Oligochaeta)
Authors: Ferraguti Marco , Fascio Umberto , Boi Silvia 
Published: October 2002

AbstractThe oligochaete annelids, belonging to the subfamily Tubificinae, produce two types of spermatozoa: eusperm (the fertilising ones) and parasperm, protecting and carrying the eusperm. The pathway for the production of the two types is common until the onset of meiosis, but then a regular meiosis produces eusperm, whereas parasperm is generated through a peculiar mechanism of nuclear fragmentation giving rise to an irregular, but very high, number of paraspermatozoa. Since every parasperm has its own flagellum, this entails the necessity of producing a very high number of basal bodies. In the present paper, we describe how basal bodies are generated through a mechanism similar to that producing the basal bodies in ciliated epithelia, but never observed up to now during the genesis of a uniflagellated cell. Basal bodies form in close proximity to a precursor structure called deuterosome, which originates de novo in the cytoplasm from fibrogranular material. The various stages of centriologenesis are positive to anti‐centrin antibodies and, observed by electron microscopy, correspond closely to the ones described for ciliated epithelia. However, once formed, the basal bodies migrate to their final position and produce the parasperm flagellum.
Barriers to the management of international operations
Authors: Klassen Robert D. , Whybark D.Clay 
Published: October 2002

AbstractThe purpose of this research was to define and rank key barriers to the effective management of international manufacturing operations. An international panel of experts, composed of practitioners, academics and consultants, was surveyed using a Delphi process to identify the key barriers, to explain the rationale for their selection and to rank them. The highest ranked barrier was general lack of a global view by management. Among the other highly ranked barriers were contemporary managerial issues like manufacturing strategy and managing international factory networks. Some traditional technical concerns like cultural and language differences and managing global logistics were also highly ranked. The responses clustered into two groups with the largest group focusing more heavily on contemporary manufacturing concerns while the other group emphasized more traditional technical topics. The results help establish priorities for developing research agendas, orienting teaching programs and focusing company resources.
On the spatially homogeneous Boltzmann equation
Authors: Mischler Stéphane , Wennberg Bernst 
Published: October 2002

We consider the question of existence and uniqueness of solutions to the spatially homogeneous Boltzmann equation. The main result is that to any initial data with finite mass and energy, there exists a unique solution for which the same two quantities are conserved. We also prove that any solution which satisfies certain bounds on moments of order

s < 2

must necessarily also have bounded energy.

A second part of the paper is devoted to the time discretization of the Boltzmann equation, the main results being estimates of the rate of convergence for the explicit and implicit Euler schemes.
Two auxiliary results are of independent interest: a sharpened form of the so called Povzner inequality, and a regularity result for an iterated gain term.

Résumé

Dans cet article nous nous intéressons aux problèmes d’existence et d’unicité pour l’équation de Boltzmann homogène. Nous montrons que pour toute donnée initiale de masse et d’énergie bornées il existe une unique solution qui conserve ces deux quantités. Nous montrons aussi que si une solution possède certains moments d’ordre

s < 2

alors nécessairement elle a une énergie initiale bornée.

Dans un deuxième temps nous montrons que les schémas d’Euler explicite et implicite de discrétisation en temps de l’équation convergent et nous donnons des taux de convergence.
Pour établir ces résultats nous utilisons de nouvelles inégalités de Povzner, ainsi qu’un lemme de régularité pour le terme de gain itéré.
The treatment of experimental osteomyelitis by surgical debridement and the implantation of calcium sulfate tobramycin pellets
Authors: Nelson Carl L. , McLaren Sandra G. , Skinner Robert A. , Smeltzer Mark S. , Thomas J. Roby , Olsen Keith M. 
Published: October 2002

AbstractCalcium sulfate was used as a biodegradable delivery system for the administration of antibiotics in musculoskeletal infection. New Zealand white rabbits were infected with Staphylococcus aureus, debrided, and randomized to one of four treatment groups: calcium sulfate pellets with 10% tobramycin sulfate, placebo calcium sulfate pellets and IM tobramycin, placebo calcium sulfate pellets, or debridement. Serum and wound exudate tobramycin concentrations and serum calcium levels were measured. Radiographs, cultures, and histology were analyzed for efficacy and treatment. Rabbits treated with 10% tobramycin sulfate pellets showed a significantly higher eradication of infection (11/13) than rabbits treated with debridement only (5/12), placebo pellets and IM tobramycin (5/14), or placebo pellets (3/13). In the group receiving 10% tobramycin sulfate pellets, serum tobramycin concentrations peaked 3 h post‐operatively at 5.87 μg/ml and were non‐detectable after day 1. In the group receiving placebo pellets and IM tobramycin, serum concentrations peaked at 7.82 μg/ml 1 h post‐operatively, fell to 6.12 μg/ml on day 2, and averaged 4.18 μg/ml for the remainder of the treatment period. The wound exudate tobramycin concentrations in the animals treated with tobramycin sulfate pellets peaked at 11.9 mg/ml on day 1 and dropped to 2.5 μg/ml on day 7. There was no significant difference in the serum calcium levels in any of the treatment groups. Calcium sulfate containing tobramycin sulfate has potential utility as a biodegradable local antibiotic delivery system in the treatment of musculoskeletal infections.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Remodeling of the gliding surface after flexor tendon repair in a canine model in vivo
Authors: Zhao Chunfeng , Amadio Peter C. , Momose Toshimitsu , Zobitz Mark E. , Couvreur Paulus , An Kai‐Nan 
Published: October 2002

AbstractMaintaining a smooth lubricated surface between the flexor tendon and sheath after tendon repair is very important for restoration of digit function. We studied the tendon surface after tendon repair mechanically in a canine model in vivo by measuring frictional force. One hundred and twenty flexor digitorum profundus (FDP) tendons were lacerated to 80% of their cross‐section and repaired with either a modified Kessler (MK) or Becker (MGH) repair. The postoperative therapeutic regimen was either synergistic wrist and digit motion (SWM) or passive digit flexion and extension with the wrist fixed in 45° of flexion (FIX). The dogs were sacrificed at one, three, or six weeks postoperatively. Thirty six FDP tendons from normal paws served as the control group, with each control tendon tested in two different conditions: intact and immediately after partial laceration and repair (0 time), making a total of five different timing points (intact, 0 time, one week, three weeks, and six weeks) for each repair type and each postoperative therapy. Frictional force between tendon and proximal pulley was evaluated after breaking any adhesions. Compared to intact tendons, friction was significantly increased immediately after tendon repair. The friction of the MK repair was significantly less than that of the MGH repair at all time and therapy groups, except at six weeks in the SWM group. For the MGH repair, at six weeks friction in the SWM group was significantly less than friction in the FIX group. This study showed that postoperative tendon gliding depends on the method of tendon repair and the postoperative therapy regimen. Furthermore, we have demonstrated that the gliding surface after tendon repair remodels with time. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Predictors of noncompliance in males with first-episode schizophrenia, schizophreniform and schizoaffective disorder
Authors: Novak-Grubic Virginija , Tavcar Rok 
Published: October 2002

SummaryPurposeMany factors influencing compliance in schizophrenia have been reported in the literature. Our aim was to assess predictors of noncompliance in male patients with first-episode schizophrenia, schizophreniform and schizoaffective disorder in a naturalistic setting.Subjects and methodsFifty-six male patients, discharged from hospital, were included in a 1-year follow-up study. Psychopathological symptoms were assessed with positive and negative syndrome scale at admission and discharge, while extrapyramidal side effects were recorded weekly during hospitalisation using the Simpson–Angus and Barnes akathisia scales. Socio-demographic and some other variables were also recorded.ResultsThirty patients (53.6%) dropped out of treatment in the first year and 21 of them relapsed. With the Cox survival analysis three predictors of noncompliance were found: diagnosis of schizophrenia versus the other two diagnoses, positive symptoms at admission, and lack of insight at discharge.DiscussionIn spite of a specific methodology and selection of only first-episode male patients, the results are in accordance with the findings of other authors. This confirms the universality of noncompliance in psychotic patients.ConclusionsFirst-episode patients have a high dropout rate. However, in compliant patients, the relapse rate was low, and therefore special attention and compliance-promoting interventions in first-episode patients are needed.