bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of transcription factor CEBP homology protein mediates hypoglycaemia‐induced necrotic cell death in human neuroblastoma cells
Authors: Kögel Donat , Svensson Birte , Copanaki Ekaterini , Anguissola Sergio , Bonner Caroline , Thurow Nadia , Gudorf Daniel , Hetschko Holger , Müller Thorsten , Peters Marion , König Hans‐Georg , Prehn Jochen H. M.
Published: August 2006

Oxygen and glucose deprivation are direct consequences of tissue ischaemia. We explored the interaction of hypoxia and hypoglycaemia on cell survival and gene expression in the absence of glutamatergic signalling using human SH‐SY5Y neuroblastoma cells as a model. In agreement with previous investigations in non‐neural cells, prolonged hypoxia (0.5% O2) failed to induce significant cell death in this system. In contrast, exposure to hypoglycaemia induced significant necrotic cell death (> 80% after 72 h). Interestingly, hypoglycaemia‐induced cell death was completely abrogated by simultaneous exposure to hypoxia, suggesting strong cytoprotective effects of hypoxia. Subsequent microarray analysis of the underlying transcriptional responses revealed that the transcription factor CEBP homology protein (CHOP) was strongly induced by hypoglycaemia, and suppressed by simultaneous hypoxia. RNA interference against CHOP significantly protected cells from glucose deprivation‐induced cell death. Hypoxia‐induced vascular endothelial growth factor (VEGF) activation also protected cells against hypoglycaemia‐induced cell death, but VEGF failed to modify hypoglycaemia‐induced CHOP induction. Our data suggest that hypoglycaemia‐induced necrotic cell death of neuroblastoma cells is an active process mediated via the induction of the transcription factor CHOP, and that hypoxia counteracts this cell death via at least two distinct mechanisms: repression of CHOP and induction of VEGF.
Involvement of 5‐HT3receptors in the development and expression of methamphetamine‐induced behavioral sensitization: 5‐HT3Areceptor channel and binding study
Authors: Yoo Ji‐Hoon , Cho Jae‐Han , Yu Hyun‐Sook , Lee Kwang‐Wook , Lee Byung‐Hwan , Jeong Sang Min , Nah Seung‐Yeol , Kim Hyoung‐Chun , Lee Seok‐Yong , Jang Choon‐Gon
Published: August 2006

Methamphetamine (MAP) is one of the most commonly abused drugs in Asia, and previous studies suggest that serotonin 3 receptors (5‐HT3) are involved in MAP‐induced locomotion and reward. However, little is known about the role of 5‐HT3receptors in MAP‐induced behavioral sensitization. Here, we measured the effects of MDL 72222, a 5‐HT3antagonist, and SR 57227 A, a 5‐HT3agonist, on the development and expression of MAP‐induced behavioral sensitization, and alternations of 5‐HT3receptor binding labeled with the 5‐HT3‐selective antagonist, [3H]GR65630, in mice. In addition, we investigated the effects of MAP on 5‐HT3Areceptor channel activity inXenopus laevisoocytes expressing 5‐HT3Areceptors. We found that MDL 72222 attenuated both the development and expression of behavioral sensitization to MAP (1.0 mg/kg, i.p.), and that this attenuating effect of MDL 72222 was reversed by pre‐treatment with SR 57227 A. In oocytes expressing 5‐HT3Areceptor, MAP exhibited a dual modulation of 5‐HT3Areceptor channel activity, i.e. pre‐treatment with a low dose of MAP (0.1 µm) enhanced 5‐HT‐induced inward peak current (I5‐HT) but a high dose of MAP (100 µm) inhibitedI5‐HT. The acute administration of MDL 72222 with MAP decreased [3H]GR65630 binding versus MAP alone in the mouse striatum. Our results suggest that MDL 72222 attenuates MAP‐induced behavioral sensitization via 5‐HT3receptors in the caudate putamen, and that 5‐HT3receptor antagonists like MDL 72222 have potential as novel anti‐psychotic agents for the treatment of MAP dependence and psychosis.
TAp73 isoforms antagonize Notch signalling in SH‐SY5Y neuroblastomas and in primary neurones
Authors: Hooper Claudie , Tavassoli Mahvash , Chapple J. Paul , Uwanogho Dafe , Goodyear Richard , Melino Gerry , Lovestone Simon , Killick Richard
Published: August 2006

p73, like Notch, has been implicated in neurodevelopment and in the maintenance of the mature central nervous system. In this study, by the use of reporter‐gene assays, we demonstrate that C‐promoter binding factor‐1 (CBF‐1)‐dependent gene transcription driven by the Notch‐1 intracellular domain (N1ICD) is potently antagonized by exogenously expressed transactivating (TA) p73 splice variants in SH‐SY5Y neuroblastomas and in primary neurones. Time course analysis indicated that the inhibitory effects of TAp73 are direct and are not mediated via the product of a downstream target gene. We found that endogenous TAp73 stabilized by either c‐Abl or cisplatin treatment also potently antagonized N1ICD/CBF‐1‐dependent gene transcription. Furthermore, western blotting revealed that exogenous TAp73 suppressed endogenous hairy and enhancer of split‐1 (HES‐1) protein levels and antagonized the increase in HES‐1 protein induced by exogenous N1ICD expression. Evidence of a direct physical interaction between N1ICD and TAp73α was demonstrated by co‐immunoprecipitation. Using Notch deletion constructs, we demonstrate that TAp73α binds the N1ICD in a region C‐terminal of aa 2094. Interestingly, ΔNp73α and TAp73αR292H also co‐purified with N1ICD, but neither inhibited N1ICD/CBF‐1‐dependent transcription. This suggests that an intact transactivation (TA) domain and the ability to bind DNA are necessary for TAp73 to antagonize Notch signalling. Finally we found that TAp73α reversed the N1ICD‐mediated repression of retinoic acid‐induced differentiation of SH‐SY5Y neuroblastomas, providing functional evidence for an inhibitory effect of TAp73α on notch signalling. Collectively, these findings may have ramifications for neurodevelopment, neurodegeneration and oncogenesis.
Mice deficient for galanin receptor 2 have decreased neurite outgrowth from adult sensory neurons and impaired pain‐like behaviour
Authors: Hobson Sally‐Ann , Holmes Fiona E. , Kerr Niall C. H. , Pope Robert J. P. , Wynick David
Published: August 2006

Expression of the neuropeptide galanin is markedly up‐regulated within the adult dorsal root ganglia (DRG) following peripheral nerve injury. We have previously demonstrated that galanin knockout (Gal‐KO) mice have a developmental loss of a subset of DRG neurons. Galanin also plays a trophic role in the adult animal, and the rate of peripheral nerve regeneration and neurite outgrowth is reduced in adult Gal‐KO mice. Here we describe the characterization of mice with an absence of GalR2 gene transcription (GalR2‐MUT) and demonstrate that they have a 15% decrease in the number of calcitonin gene‐related peptide (CGRP) expressing neuronal profiles in the adult DRG, associated with marked deficits in neuropathic and inflammatory pain behaviours. Adult GalR2‐MUT animals also have a one third reduction in neurite outgrowth from cultured DRG neurons that cannot be rescued by either galanin or a high‐affinity GalR2/3 agonist. Galanin activates extracellular signal‐regulated kinase (ERK) and Akt in adult wild‐type (WT) mouse DRG. Intact adult DRG from GalR2‐MUT animals have lower levels of pERK and higher levels of pAkt than are found in WT controls. These data suggest that a lack of GalR2 activation in Gal‐KO and GalR2‐MUT animals is responsible for the observed developmental deficits in the DRG, and the decrease in neurite outgrowth in the adult.
Isolation and characterization of polymorphic microsatellite loci from Aucoumea klaineana Pierre (Burseraceae), a tropical rainforest tree of Central Africa
Authors: BORN C. , VIGNES H. , MULOKO N. , WICKINGS E. J. , HOSSAERT‐MCKEY M. , CHEVALLIER M. H.
Published: August 2006

Nineteen microsatellite loci were isolated using an enrichment protocol from Aucoumea klaineana Pierre (Okoumé, Burseraceae), a tropical rainforest tree of Central Africa. Polymorphism was investigated using 56 trees distributed throughout Gabon (four trees from 14 populations). All loci were polymorphic, with the number of alleles ranging from two to 15. High levels of variation were found among loci, and observed heterozygosity ranged from 0.05 to 0.77. These loci will be useful for the in‐depth analysis of population structure and phylogeographical variation throughout the distribution range of Okoumé.
Characterization of microsatellite loci isolated in trumpeter swan (Cygnus buccinator)
Authors: JOHN JUDY ST. , RANSLER FINDLEY A. , QUINN THOMAS W. , OYLER‐MCCANCE SARA J.
Published: August 2006

Primers for 16 microsatellite loci were developed for the trumpeter swan (Cygnus buccinator), a species recovering from a recent population bottleneck. In a screen of 158 individuals, the 16 loci were found to have levels of variability ranging from two to seven alleles. No loci were found to be linked, although two loci repeatedly revealed significant departures from Hardy–Weinberg equilibrium. Amplification in the closely related tundra swan (Cygnus columbianus) was successful for all except one locus. These microsatellite loci will be applicable for population genetic analyses and ultimately aid in management efforts.
Characterization of 11 microsatellite marker loci in the Malagasy big‐headed turtle (Erymnochelys madagascariensis)
Authors: RAFELIARISOA TSILAVO , SHORE GARY , ENGBERG SHANNON , LOUIS EDWARD , BRENNEMAN RICK
Published: August 2006

The Malagasy big‐headed turtle (Erymnochelys madagascariensis) is the only Erymnochelys species living in lakes, rivers and watersheds of western Madagascar. This species is endangered due to over harvesting of natural populations for human consumption. Eleven nuclear microsatellite loci were isolated from a genomic DNA library derived from a free‐ranging Malagasy big‐headed turtle from the Beroboka Classified Forest, Madagascar. Population genetic parameters were estimated on 10 individuals sampled from Ampijoroa and Andranohobaka River, Madagascar, to determine marker utility and as preliminary baseline values to study future populations in these locations.
Isolation and characterization of trinucleotide repeat microsatellite markers for Plutella xylostella L.
Authors: ESSELINK G. D. , DEN BELDER E. , ELDERSON J. , SMULDERS M. J. M.
Published: August 2006

Thirteen microsatellite markers generating high quality patterns have been developed and characterized for diamondback moth (Plutella xylostella L.), of which 11 are based on trinucleotide repeats. These markers are polymorphic, generating up to 15 alleles in a test set of 12 caterpillars. The markers will be useful to assess the differentiation of P. xylostella populations and the exchange of pest populations between sites with crops, green manure crops and weeds.
Polymorphic microsatellite markers for the Iberian rock lizard species, Iberolacerta cyreni, and cross‐species priming in other Iberolacerta species
Authors: BLOOR P.
Published: August 2006

Eight polymorphic microsatellite loci are described for the Iberian rock lizard species, Iberolacerta cyreni. Loci were isolated from a partial genomic library that had been enriched for AAAG repeat sequence. Number of alleles per locus ranged from two to 13 in a sample of 24 individuals from the Sierra de Guadarrama (central Spain). Observed heterozygosity ranged from 0.13 to 0.96. At least three loci were amplified and polymorphic in four other Iberian rock lizard species: Iberolacerta monticola, Iberolacerta bonnali, Iberolacerta aranica and Iberolacerta aurelioi. These markers will be used to study mating strategies and reproductive success in I. cyreni.
Isolation and characterization of eight microsatellite loci from Picnic seabream (Acanthopagrus berda)
Authors: JEAN C. T. , LEE S. C. , LIU C. W. , TSENG M. C.
Published: August 2006

Acanthopagrus berda (Sparidae) is abundant in estuaries and inshore waters of the tropical Indo‐Pacific oceans. Because of the drastic decrease in the species’ wild populations, there is an urgent need to understand its population structure. Eight microsatellite loci were isolated from A. berda. An analysis of 50 individuals from Tapeng Lagoon, southwestern Taiwan demonstrated a low degree of diversity. The allelic numbers ranged from nine to 20. The observed heterozygosity (HO) ranged from 0.28 to 0.64 (mean, 0.45). We also investigated the prospective value of the microsatellite primers to examine whether they were applicable to related taxa.
Development of microsatellite DNA markers of silver carp (Hypophthalmichthys molitrix) and their cross‐species application in bighead carp (Aristichthys nobilis)
Authors: LIAO MEIJIE , YANG GUANPIN , WANG XIAOCHEN , WANG DENGQIANG , ZOU GUIWEI , WEI QIWEI
Published: August 2006

Forty‐four microsatellite DNA markers were developed for silver carp, and used to investigate polymorphisms of 41 wild silver carps and seven wild bighead carps collected from Jingzhou fragment of Yangtze River. In silver carp, 40 markers were polymorphic. A total of 297 alleles were detected at 40 polymorphic loci. The number of alleles per locus varied from two to 16 with an average of 7.4 and the expected heterozygosities of each locus ranged from 0.07 to 0.91 with an average of 0.69. All markers amplified both silver carp and bighead carp DNAs.
Factors influencing territorial occupancy and reproductive output in the Booted Eagle Hieraaetus pennatus
Authors: MARTÍNEZ JOSÉ E. , PAGÁN ILUMINADA , CALVO JOSÉ F.
Published: August 2006

During a 7‐year research project in a forested area of southeastern Spain, we studied territorial occupancy and reproductive success in a Booted Eagle Hieraaetus pennatus population. We monitored 65 territories, gathering information on 406 occupancy events and 229 breeding attempts, including those of two potential competitors, the Northern Goshawk Accipiter gentilis and the Common Buzzard Buteo buteo. Generalized linear mixed models were used to explain occupancy and productivity, by evaluating the relative contribution of three different types of variables (habitat, competition and past events) and considering territory as a random effect. We examined a set of a priori hypothesized models, together with a number of additional models, and selected the best models following an information‐theoretic approach. Our best models related territorial occupancy and productivity to previous breeding success (the fledging of one or two young), which appeared to be the most important factor determining the probability of reoccupation and the reproductive output in the subsequent year. The best occupation model revealed that the probabilities of occupancy were also conditioned by a competition variable (intraspecific nearest‐neighbour distance) and two habitat variables (the location of the nest on the valley slope and the distance to the nearest forest track). Unlike the best occupation model, however, the selected model for reproductive output did not incorporate any competition variable besides previous breeding success, but included another two habitat variables (the effects of trunk height and NNE orientation).
Comparison between aortic annulus motion and mitral annulus motion obtained using echocardiography
Authors: Emilsson K. , Egerlid R. , Nygren B. M.
Published: August 2006

Earlier studies have shown that the aortic root, in analogy with the mitral annulus, moves towards the left ventricular apex during systole. However, there are no earlier studies comparing the amplitude of the aortic annulus motion (AAM) with that of the mitral annulus (MAM), which was the main aim of the study. Another aim was to study the intra‐ and interobserver reproducibility (IIOR) of measuring AAM with M‐mode and 2‐D echocardiography as it is not obvious which of the methods that should be used. Twenty‐one healthy subjects were examined by echocardiography. AAM and MAM were measured at different sites. IIOR was measured in 10 of the subjects. There was no significant difference between average AAM (15·3 ± 1·5 mm) and average MAM (15·6 ± 1·5 mm) and there was a rather good agreement between the variables. There was also no significant difference between AAM at the septal site (16·3 ± 2 mm) and average MAM, but a significant difference between AAM at the lateral site (14·2 ± 1·6 mm) and average MAM (P<0·001) and between the both sites of measuring AAM (P<0·001). The significant difference between the two sites of measuring AAM may have anatomical reasons but may also depend on difficulties in measuring AAM at the septal site where it has lower reproducibility than at the lateral site. IIOR of measuring AAM was good when using M‐mode but poor when using 2‐D echocardiography and AAM should preferably be measured using M‐mode and not using 2‐D echocardiography.
The effects of unilateral transcutaneous electrical nerve stimulation of the median nerve on bilateral somatosensory thresholds
Authors: Dean Jaqueline , Bowsher David , Johnson Mark I.
Published: August 2006

Transcutaneous electrical nerve stimulation (TENS) is used to relieve acute and chronic pain. TENS electrodes are applied at the site of pain or in segments related to the pain, although there is limited research to support either approach. This study investigated the effects of unilateral TENS on mechanical and thermal thresholds at ipsilateral and contralateral sites in healthy human participants. Sensory perception thresholds were measured on the ipsilateral and contralateral thenar eminence of 16 volunteers for von Frey filaments, sharpness, warm, cold and heat pain. TENS was administered over the right median nerve for 10 min at 100 pulses per second (pps) and an intensity which elicited mild tingling in the hand. During TENS, ipsilateral threshold was greater than contralateral threshold for all sensory modalities, although differences were less marked for thermal stimuli. TENS effects had disappeared 30 min after TENS had been switched off although there was a tendency for thermal thresholds to remain elevated. We conclude that during stimulation, TENS elevates somatosensory thresholds within the distribution of the stimulated nerve. The rapid and short‐lived ipsilateral effect is consistent with findings from animal studies and suggests a central segmental mechanism.
An Approach to the Modeling and Analysis of Software Production Processes
Authors: Elmaghraby S.E. , Baxter E.I. , Vouk M.A.
Published: August 2006

We propose an approach to the analysis and design of software production processes that is based on a new paradigm which we coin ‘PETAN’. It is a blend of concepts from Petri nets theory and activity nets theory. The paper reviews the relevant concepts from activity nets and demonstrates the applicability of the new paradigm by a sample implementation to real life software production processes through simulation using SLAM II language.
Basic Concepts of the Design Methodology for Production Management Systems: a State‐of‐the‐Art
Authors: Chen D.
Published: August 2006

This paper gives at first an overview of the basic definitions and concepts involved in a design methodology. Then, a state‐of‐the‐art on the elements of the design methodology for Production Management Systems is presented. Last, we give a concluding summary on the perspective of the PMS design approaches in the future.
Vehicle Routing and Production Planning Decision Support Systems: Designing Graphical User Interfaces
Authors: Maturana S. , Eterovic Y.
Published: August 2006

Given the inherent complexity of vehicle routing and production planning decision support systems, designing user interfaces for them is challenging and can make a big difference in the usability of these systems. Many heuristic and optimization‐oriented systems that have been implemented for this type of problem have failed in part due to a poor graphical user interface. This work proposes an approach that can be applied to improve the design of user interfaces for this type of system and make its implementation easier. The approach is based on tools that were adapted from the FW/SM system for Structured Modeling and commercially available tools, such as Powerbuilder and CPLEX. Two systems that were implemented using this approach, in two different firms, are presented. These systems run on standard PCs under MS Windows, follow the Windows applications design guidelines, and interact with relational database management systems.
A Contextual Approach for Designing and Using OR Quantitative Models
Authors: Yoshizaki H.T.Y. , Plonski G.A.
Published: August 2006

Practitioners of Operations Research (OR) traditionally concentrate on mathematical and computational aspects of quantitative models, sometimes resulting in risky implementation or early model obsolescence. We propose an approach, inspired by system concepts and technology management, which includes softer influences, such as decision frequency, model life cycle and technological stage of management, to help modeling and model management decisions. Some graphic indicators are developed to help diagnosis and conception.
Optimization and Neural Network in New Product Development
Authors: Lin C. , Madu C.N. , Kuei C.H. , Yeh J.M.
Published: August 2006

New product introduction is vital to a firm's growth and prosperity. A company needs to develop a process to determine how to find and develop new product ideas and finally, how to successfully introduce them into the marketplace. To address this problem, this study proposes a new approach that combines neural network, analytic hierarchy process (AHP) and linear programming (LP). A neural network is used to classify the feasibility of ideas/projects in new product development and the theory of AHP is applied to evaluate the interdependence among projects. A linear programming model is then developed and used to allocate the limited financial resources of the firm to the competing projects.
The Decision Value of Management Support Systems for Strategic Hospital Management
Authors: Forgionne G.A. , Kohli R.
Published: August 2006

Several studies have shown that selected management support systems (MSS) favorably impact decision making. Others have theorized that additional benefits could be achieved by consolidating the separate system functions to form an integrated management support system. There have been few, if any, reported empirical tests of this theory. This article offers empirical evidence on integrated MSS effectiveness. It points to the general literature on MSS effects, notes an empirical gap in this literature, and reports the results of experiments that assess the influences of a specific integrated MSS on the process and outcomes of strategic hospital decision making.
A Model for Optimizing Options and Futures
Authors: Murtagh B.A. , Murtagh R.W.
Published: August 2006

This paper discusses the use of options and futures in minimizing the domestic currency cost of repaying a foreign currency debt. Because of the significant uncertainty in predicting the exchange rate at some future time, we develop a methodology for exploring the range of predictions for which it is optimal to hedge with futures, the range for which it is optimal to use options, and the range for which it is optimal to use a combination of both. Implementation of a nonlinear integer stochastic programming model is described and computational experience discussed.
Chaos Theory in Operations Research
Authors: Feichtinger G.
Published: August 2006

The purpose of this paper is to illustrate the potential importance of non‐linear dynamical systems theory in OR. After a brief introduction into some basic concepts. We study an advertising diffusion model to exemplify the composition of chaos and optimalily in dynamic programming. It turns out that economies of scale may imply period three cycle and consequently topological chaos. Furthermore, we present an outlook to further potential applications of non‐linear dynamical systems in OR/MS queing systems are briefly discussed whose random coding fluctuations are endogenously generated in a pure deterministic framework. Among the various paradigms favouring complex behaviour are dynamic strategic interactions, slow‐fast systems, and cellular automata.
Modeling Truck–Shovel Systems as Closed Queueing Network with Multiple Job Classes
Authors: Muduli P.K. , Yegulalp T.M.
Published: August 2006

In this paper an analytical method is proposed to model the truck–shovel system as a closed queueing network with multiple job classes. This approach would provide the capability of estimating system performance measures (mine throughput, mean number of trucks, mean waiting time etc.) for planning purposes when the truck fleet is not necessarily composed of identical trucks. A computational study is presented to show how choosing different types of trucks affect the production level in a truck–shovel system. Mean Value Analysis (MVA) approach is used to compute all performance measures of the truck–shovel system.
Systems Simulation to Support Integrated Energy Analysis and Liberalised Planning
Authors: Bunn D. , Dyner I.
Published: August 2006

This paper describes the application of system dynamics to two very different energy policy contexts, both of which constitute key issues of the 1990s. On the one hand there is the global concern about sustainability and the financing of new energy capacity which has motivated integrated energy planning as a means to accommodate conservation and other demand‐side measures. On the other hand, there is the rapid restructuring and privatisation of public utilities, world‐wide, into competitive markets. These trends not only appear to pose conflicting policy objectives, e.g. planning versus liberalised market‐forces, they also pose a modelling challenge. This paper investigates how far systems modelling and simulation can provide the broad policy oriented framework required for these new purposes. Applications to the UK and Colombia are presented to explore some of the new issues which need to be integrated on this modelling platform.
On the Development of New Forms of Organisational Decision Support Systems
Authors: Lockett G. , Naudé P.
Published: August 2006

Decision making has been a primary interest of OR/MS, and management scientists have been at the forefront of developments. But the rate of inplementation has not been high, compared to the application of general PC‐based decision support tools. Where there has been some recent success is in the area of judgmental modelling. Examples of exploitation on business problems have been reported and these individual cases are extremely valuable in providing insights into the organisational contexts in which the problems are embedded. However most of them are applications on very simple problems and no real implementation is reported. This paper attempts to overcome this deficiency by looking at a much richer organisational environment and considers two largely unexplored aspects of the decision process, namely its longitudinal nature and the group dimension. In this paper we present and discuss the results of three case studies which look into the use of models in a longitudinal decision process, and introduce the associated application of psychological profiling of the group of decision makers involved. All the cases are based in real organisational settings and are not laboratory experiments and therefore little statistical significance can be assigned to the results. But they do provide rich insights into the organisational complexity that surrounds many decisions which should help produce better management tools. The preliminary results suggest that we need to take such characteristics into account when building decision making models if we are to enhance the understanding of the decision without inhibiting behaviour.
Using Mathematical Programming for Electricity Spot Pricing
Authors: Hogan W.W. , Read E.G. , Ring B.J.
Published: August 2006

Recent moves around the world to introduce competition into electricity markets have created a need for mechanisms to determine electricity spot prices which provide good incentives for market coordination. Duality theory suggests that such prices can be found by solving a mathematical program. We derive implicit prices corresponding to an actual half‐hourly dispatch of a full a.c. power system, and discuss the application of spot pricing in New Zealand and the United States.
Modelling Hydro Reservoir Operation in a Deregulated Electricity Market
Authors: Scott T.J. , Read E.G.
Published: August 2006

We describe a medium term market simulation model which was built to help analyse the effects of contracts, and of company structure, on the efficiency of a wholesale electricity market. Our approach employs a Dual Dynamic Programming methodology, with the sub‐models at each stage being Cournot duopolies. The model played a part in the analysis which helped shape the recent New Zealand Government decisions which move the industry towards a market driven structure. Although similar moves have been made in other countries in recent years, and there have been several electricity market studies reported recently in the literature, gaming by mixed hydro‐thermal firms does not seem to have been modelled previously.
The Optimisation of Renewable Energy Sources in an Electrical Power System by Use of Simulation and Deterministic Planning Models
Authors: Watson S.J. , Ter‐Gazarian A.G.
Published: August 2006

This paper presents two models which have been developed to study the operational and economic impact of integrating renewable power sources in a large scale electricity grid. The first of these models simulates the hour‐by‐hour operation of the grid and how conventional power plant is scheduled to accommodate renewable power sources in order to meet the total demand. The second model is a deterministic model model which assesses the economics of renewable power sources alongside conventional forms of power generation. Results are presented showing how the two models can be used together in order to study the operational and economic impact of wind and photovoltaic power when integrated into the electrical grid systems of England and Wales, the Republic of Ireland and Portugal.
Improving Electricity Planning – Use of a Multicriteria Decision Making Model
Authors: Mills D. , Vlacic L. , Lowe I.
Published: August 2006

Electricity supply planners are now expected to consider a wide range of supply and demand options to meet future power needs. The evaluation is also expected to consider multiple objectives in such diverse areas as quality of supply, cost, environmental and social impacts. Further, there are a range of views on the appropriated weightings for those various considerations. Traditional methods for determining choices are no longer adequate. This paper outlines the development of a powerful tool to facilitate a multiobjective‐driven electricity planning process. The multicriteria decision making model allows the evaluation of options against a wide range of criteria, grouped in a hierarchical structure. A formalism for comparing options is explored, showing that the model allows a planner to compare the range of alternatives against both a desired level of performance and a minimum acceptable level. The architecture of a computer‐based decision support system is briefly described.
Minimization of Energy Losses in Electric Power Distribution Systems by Intelligent Search Strategies
Authors: Cavellucci C. , Lyra C.
Published: August 2006

Energy is continuously dissipated in electric power systems due to electrical resistance in transmission and distribution lines. This paper addresses the problem of obtaining a network topology with minimum energy losses for electric power distribution systems. As distribution networks must operate radially, the problem can be formulated as a generalization of the minimum spanning tree problem. The generalization is due to variation in costs as network configuration changes. Nonlinear network flow techniques are teamed with search strategies borrowed from the field of artificial intelligence to overcome computation intractability.
A Bayesian Approach to Batch Process Scheduling
Authors: Mockus L. , Reklaitis G.V.
Published: August 2006

The problem of decision timing in the context of batch scheduling is addressed in this paper. The representation of time in any scheduling model affects the number of integer variables and the convexity of the model. The usual procedure in batch process scheduling is to divide the scheduling horizon into equal size intervals to achieve the required accuracy. This construction generates a formulation with a potentially large number of binary variables. In this paper, the time events arising in the schedule are modeled directly, and thus the use of binary variables over periods during which no changes in system state occur is avoided. The problem is formulated as a mixed integer nonlinear program (MINLP). The Bayesian heuristic (BH) approach is used to implement a global optimization algorithm which effectively solves the resulting model. Computational comparisons using two text examples are made against a UDM (uniform discretization model) formulation. The results suggest that the BH approach combined with the nonuniform time discretization formulation shows promise for the solution of batch scheduling problems.
Integrative Systems Methodology: Heuristic for Requisite Variety
Authors: Schwaninger M.
Published: August 2006

The author introduces a new methodological framework for dealing with complex issues, named Integrative Systems Methodology (ISM). ISM is a general heuristic to help actors in organizations and society achieve requisite variety. For this purpose, numerous “problem solving” approaches have been developed. ISM is aimed at overcoming the drawbacks of many established methodologies. It emphasizes an extended perspective outlining a process which operates on both levels, “content” and “context”, synchronically. At the same time, ISM leverages the complemenarities of positivistic/representationist and hermeneutic/interpretive perspectives and allows for combining qualitative and quantitative modelling techniques. The potential of ISM is illustrated by means of an up‐to‐date case study, in which different methodologies are synthesized to overcome their respective limitations. Several applications developed over the years have led to new insights which enable the handling of complexity more effectively with the help of ISM.
Weighted Dantzig–Wolfe Decomposition for Linear Mixed‐integer Programming
Authors: Wentges P.
Published: August 2006

Dantzig–Wolfe decomposition can be used to solve the Lagrangian dual of a linear mixed‐integer programming problem (MIP) if the dual structure of the (MIP) is exploited via Lagrangian relaxation with respect to the complicating constraints. In the so‐called weighted Dantzig–Wolfe decomposition algorithm, instead of the optimal solution of the Dantzig–Wolfe master problem a specially weighted average of the previously constructed Lagrangian multipliers and the optimal solution of the master problem is used as Lagrangian multiplier for the next Lagrangian subproblem to be solved. A convergence proof of the weighted Dantzig–Wolfe decomposition algorithm is given, and some properties of this procedure together with computational results for the capacitated facility location problem are discussed.
On the Efficient Location of Pumping Facilities in an Aquifer System
Authors: Cunha M.D.C. , Pais Antunes A.
Published: August 2006

In this paper, the authors present a multiple objective model that explicitly integrates the many facets of aquifer planning problems but, at the expenses of some simplifications, avoids some of the aspects that make them almost intractable from a mathematical standpoint. The model may be used to good advantage in the process of identifying efficient solutions for the location and size of pumping facilities, as well as their area of influence.
A Modified Quasi‐Newton Method for Optimization in Simulation
Authors: Kao C. , Song W.T. , Chen S‐P.
Published: August 2006

Optimization in Simulation is an important problem often encountered in system behavior investigation; however, the existing methods such as response surface methodology and stochastic approximation method are inefficient. This paper presents a modification of a quasi‐Newton method, in which the parameters are determined from some numerical experiments. To demonstrate the validity of the devised method, two examples resembling theM/M/1queueing problem are solved. The closeness of the converged solutions to the optimal solutions and a comparison with two stochastic approximation methods indicate that the modified quasi‐Newton method as devised in this paper is a robust and efficient method for solving optimization problems in simulation.
Ranking the Sites for Low‐ and Intermediate‐Level Radioactive Waste Disposal Facilities in Croatia
Authors: Petraš J.C.E.
Published: August 2006

This paper describes the procedure of identification and ranking of the potential sites for LILRW disposal facilities in Croatia. It presents preliminary results of the final phase of the site survey stage, i.e. preliminary comparison and ranking of potential sites. The potential sites were chosen on the basis of exclusionary (rejection) criteria, and the preliminary ranking of the sites was performed on the basis of comparative preference criteria by the multicriteria analysis approach PROMETHEE. The list of exclusionary and comparative criteria is given, and the weighting factors of comparative criteria are presented.
Strike Rate Matrices for Integrating Marketing and Production During the Tendering Process in Make‐to‐Order Subcontractors
Authors: Kingsman B.G. , Mercer A.
Published: August 2006

Make‐to‐order companies manufacture products to the customers’ specifications. Sales wishes to quote small mark‐ups and short lead‐times to maximise the chance of winning orders. Manufacturing wants to have large mark‐ups and long lead‐times to ensure production profitability and flexibility. The selling and manufacturing functions are integrated at the tendering stage by predicting the probability of winning contracts with various mark‐up and lead‐time combinations. Tender subdivisions, having different strike rate matrices, are determined empirically from previous outcomes and the whole process is updated continuously.
The Existence of a Short Sequence of Admissible Pivots to an Optimal Basis in LP and LCP
Authors: Fukuda K. , Lüthi H‐J. , Namiki M.
Published: August 2006

We say an LP (linear programming) is fully nondegenerate if both the primal and the dual problems are nondegenerate. In this paper, we prove the existence of a sequence of |B∖B| admissible pivot from any basis B (not necessarily feasible) to the unique optimal basis B, if the given LP has an optimal solution and is fully nondegenerate. Here admissible pivots are those pivots (satisfying certain sign conditions) that exist if the current LP dictionary is not terminal, i.e., neither optimal, inconsistent nor dual inconsistent. A natural extension of the result to LCPs (linear complementarity problems) with sufficient matrices is given. The existence itself does not yield a strongly polynomial pivot algorithm for LPs but provides us with a good motivation to study the class of admissible pivot methods for LPs, as opposed to the narrower class of simplex methods for which the shortest sequence of pivots is not known to be polynomially bounded.
VLSI Placement Using Quadratic Programming and Network Partitioning Techniques
Authors: Kennings A. , Vannelli A.
Published: August 2006

VLSI cell placement involves positioning cells within a target placement geometry while minimizing the interconnecting wire length and placement area. In this paper, the placement problem is solved using a combination of quadratic programming, circuit partitioning, clustering and greedy cell interchange heuristics. The solution of a sequence of quadratic programs and circuit partitioning problems provides the general positions of cells in high quality palcement. Computational efficiency is achieved by using an interior point method for solving the sequence of quadratic programs. A very efficient clustering heuristic is used to keep important groups of cells together as the cells are spread throughout the placement area. Numerical results on a set of benchmark circuits illustrate that this new approach produces standard cell placements that are up 17% better in wire length. 14% better in row length and up to 25 times faster than a well known Simulated Annealing placement heuristic.
An Inspection Policy for Deteriorating Processes Using Delay‐Time Concept
Authors: Okumura S.
Published: August 2006

A method for determining the discrete time points of inspection for a deteriorating single‐unit system under condition‐based maintenance is developed. The system is in a normal state, a symptom state or a failed state. A delay‐time model is utilized to describe the transition of the states. The transition time from a normal state to a symptom state and that from a symptom state to a failed state are derived assuming continuous deteriorating processes based on a reaction rate model which is categorized as a failure physics model. Failed‐dangerous and failed‐safe probabilities of an imperfect inspection are considered. A method for minimizing the long‐run average cost per unit time is formulated. The characteristics and sensitivity of the proposed method are investigated.
Genetic Algorithms for Vehicle Dispatching
Authors: Leclerc F. , Potvin J‐Y. , Potvin J.Y.
Published: August 2006

Decisions regarding the dispatch of transportation vehicles for servicing customer requests is mostly based on human expertise. In this paper, genetic algorithms are proposed as a means to support vehicle dispatchers in the context of a courier or express mail service. Vehicle dispatching is first modeled as a multiattribute choice problem. Then, a genetic algorithm is used to find a weighting scheme for the attributes that best reproduces the expert's decision process. Numerical results are reported on data collected from an operations day of a courier service company.
A Genetic Algorithm for Solving the Container Loading Problem
Authors: Gehring H. , Bortfeldt A.
Published: August 2006

The paper presents a genetic algorithm (GA) for the container loading problem. The main ideas of the approach are first to generate a set of disjunctive box towers and second to arrange the box towers on the floor of the container according to a given optimization criterion. The loading problem may include different practical constraints. The performance of the GA is demonstrated by a numerical test comparing the GA and several other procedures for the container loading problem.
Exact Solution of Cutting Stock Problems Using Column Generation and Branch‐and‐Bound
Authors: de Carvalho J.M. Valério
Published: August 2006

This paper describes an attempt to solve the one‐dimensional cutting stock problem exactly, using column generation and branch‐and‐bound. A new formulation is introduced for the one‐dimensional cutting stock problem that uses general integer variables, not restricted to be binary. It is an arc flow formulation with side constraints, whose linear programming relaxation provides a strong lower bound. In this model, a cutting pattern, which corresponds to a path, is decomposed into single arc variables. The decomposition serves the purpose of showing that it is possible to combine the branch‐and‐bound method with variable generation. Computational times are reported for one‐dimensional cutting stock instances with a number of orders up to 30.
Mathematical Model and Solution Method of Optimization Problem of Placement of Rectangles and Circles Taking into Account Special Constraints
Authors: Stoyan Y.G. , Yaskov G.N.
Published: August 2006

A mathematical model of the problem is constructed. A feasible region and peculiarities of the problem are investigated. Extremum of a linear objective function is searched at extreme points. To solve the problem a solution method based on a combination of the branch‐and‐bound algorithm and the reduced gradient method is utilized. A search tree for sorting all the extreme points of the feasible region is constructed. A stepwise passage from one extreme point to another towards decreasing the objective function is given. Appropriate software has been developed. To illustrate results of calculations the examples are given.
Parallel Algorithms for Large‐scale Nonlinear Optimization
Authors: Phua P.K‐H. , Fan W. , Zeng Y.
Published: August 2006

Multi‐step, multi‐directional parallel variable metric (PVM) methods for unconstrained optimization problems are presented in this paper. These algorithms generate several VM directions at each iteration, dierent line search and scaling strategies are then applied in parallel along each search direction. In comparison to some serial VM methods, computational results show that a reduction of 200% or more in terms of number of iterations and function/gradient evaluations respectively could be achieved by the new parallel algorithm over a wide range of 63 test problems. In particular, when the complexity, or the size of the problem increases, greater savings could be achieved by the proposed parallel algorithm. In fact, the speedup factors gained by our PVM algorithms could be as high as 28 times for some test problems.
A Branch and Bound Algorithm for An Uncapacitated Facility Location Problem with a Side Constraint
Authors: Klose A.
Published: August 2006

In this paper, a branch and bound algorithm for solving an uncapacitated facility location problem (UFLP) with an aggregate capacity constraint is presented. The problem arises as a subproblem when Lagrangean relaxation of the capacity constraints is used to solve capacitated facility location problems. The algorithm is an extension of a procedure used by Christofides and Beasley (A tree search algorithm for the p‐median problem. European Journal of Operational Research, Vol. 10, 1982, pp. 196–204) to solve p‐median problems and is based on Lagrangean relaxation in combination with subgradient optimization for lower bounding, simple Lagrangean heuristics to produce feasible solutions, and penalties to reduce the problem size. For node selection, a jump‐backtracking rule is proposed, and alternative rules for choosing the branching variable are discussed. Computational experience is reported.
Agile Manufacturing and Management of Variability
Authors: Tan B.
Published: August 2006

In this study, the relationship between agile manufacturing and management of variability is discussed. First, the key concepts of agility and agile manufacturing are introduced. These key concepts are then related to the management of variability. Previous studies on the modeling of variability of manufacturing systems are reviewed. Then the effects of variability of the structure of the production system, and also the processing time variability on the performance of a manufacturing system are studied by utilizing a simple model of a synchronous production line with identical stations and random processing times. Numerical results that examine the effects of the coefficient of variation of service time and the number of stations on the variability of the cycle time are also given.
A Mixed Integer Programming Model of the Logistics of Sulfuric Acid in Chile
Authors: Maturana S. , Contesse L.
Published: August 2006

The logistics of sulfuric acid in Chile have become increasingly important as stricter environmental laws are enacted and enforced. Large copper companies are very concerned about this problem since they are both producers and consumers of sulfuric acid. Since storing, shipping and disposing of sulfuric acid is relatively expensive, there is a strong incentive for optimizing its logistics. This paper describes a model developed for the largest copper producer in Chile to analyze, at a strategic level, the problem of the logistics of sulfuric acid in Chile.