bluuebunny/crossref_metadata_2025 huggingface dataset:
Antimutagenicity and Antiproliferative Studies of Lipidic Extracts from White Shrimp (Litopenaeus vannamei)
Authors: Wilson-Sanchez Griselda , Moreno-Félix Carolina , Velazquez Carlos , Plascencia-Jatomea Maribel , Acosta Anita , Machi-Lara Lorena , Aldana-Madrid María-Lourdes , Ezquerra-Brauer Josafat-Marina , Robles-Zepeda Ramón , Burgos-Hernandez Armando
Published: January 2011

An organic extract from fresh shrimp (Litopenaeus vannamei) was studied for antimutagenic and antiproliferative properties using Salmonella typhimurium tester strains TA98 and TA100 with metabolic activation (S9) and a cancer cell line (B-cell lymphoma), respectively. Shrimp extract was sequentially fractionated by thin layer chromatography (TLC) and each fraction was tested for antimutagenic and antiproliferative activities. Crude organic extracts obtained from shrimp reduced the number of revertants caused by aflatoxina B1, showing a dose-response type of relationship. Sequential TLC fractionation of the active extracts produced several antimutagenic and/or antiproliferative fractions. These results suggested that the lipid fraction of the tested species contained compounds with chemoprotective properties that reduce the mutagenicity of AFB1 and proliferation of a cancer cell line.
Reduction of Diphenyl Diselenide and Analogs by Mammalian Thioredoxin Reductase Is Independent of Their Gluthathione Peroxidase-Like Activity: A Possible Novel Pathway for Their Antioxidant Activity
Authors: Sausen de Freitas Andressa , De Souza Prestes Alessandro , Wagner Caroline , Haigert Sudati Jéssie , Alves Diego , Oliveira Porciúncula Lisiane , Kade Ige Joseph , Teixeira Rocha João Batista
Published: January 2011

Since the successful use of the organoselenium drug ebselen in clinical trials for the treatment of neuropathological conditions associated with oxidative stress, there have been concerted efforts geared towards understanding the precise mechanism of action of ebselen and other organoselenium compounds, especially the diorganyl diselenides such as diphenyl diselenide, and its analogs. Although the mechanism of action of ebselen and other organoselenium compounds has been shown to be related to their ability to generally mimic native glutathione peroxidase (GPx), only ebselen however has been shown to serve as a substrate for the mammalian thioredoxin reductase (TrxR), demonstrating another component of its pharmacological mechanisms. In fact, there is a dearth of information on the ability of other organoselenium compounds, especially diphenyl diselenide and its analogs, to serve as substrates for the mammalian enzyme thioredoxin reductase. Interestingly, diphenyl diselenide shares several antioxidant and neuroprotective properties with ebselen. Hence in the present study, we tested the hypothesis that diphenyl diselenide and some of its analogs (4,4’-bistrifluoromethyldiphenyl diselenide, 4,4’-bismethoxy-diphenyl diselenide, 4.4’-biscarboxydiphenyl diselenide, 4,4’-bischlorodiphenyl diselenide, 2,4,6,2’,4’,6’-hexamethyldiphenyl diselenide) could also be substrates for rat hepatic TrxR. Here we show for the first time that diselenides are good substrates for mammalian TrxR, but not necessarily good mimetics of GPx, and vice versa. For instance, bis-methoxydiphenyl diselenide had no GPx activity, whereas it was a good substrate for reduction by TrxR. Our experimental observations indicate a possible dissociation between the two pathways for peroxide degradation (either via substrate for TrxR or as a mimic of GPx). Consequently, the antioxidant activity of diphenyl diselenide and analogs can be attributed to their capacity to be substrates for mammalian TrxR and we therefore conclude that subtle changes in the aryl moiety of diselenides can be used as tool for dissociation of GPx or TrxR pathways as mechanism triggering their antioxidant activities.
3-Acetyloxy-2-cyano-2-(alkylaminocarbamoyl)propyl Groups as Biodegradable Protecting Groups of Nucleoside 5´-mono-Phosphates
Authors: Ora Mikko , Mäntyvaara Anne , Lönnberg Harri
Published: January 2011

Thymidine 5´-bis[3-acetyloxy-2-cyano-2-(2-phenylethylcarbamoyl)propyl]phosphate (1) has been prepared and the removal of phosphate protecting groups by hog liver carboxyesterase (HLE) at pH 7.5 and 37 °C has been followed by HPLC. The first detectable intermediates are the (RP)- and (SP)-diastereomers of the monodeacetylated triester 14, which subsequently undergo concurrent retro-aldol condensation to diester 4 and enzyme-catalyzed hydrolysis to the fully deacetylated triester 15. The former pathway predominates, representing 90% of the overall breakdown of 14. The diester 4 undergoes the enzymatic deacetylation 700 times less readily than the triester, but gives finally thymidine 5´-monophosphate as the desired main product. To elucidate the potential toxicity of the electrophilic 2-cyano-N-(2-phenylethyl)acrylamideby-product 17 released upon the deprotection, the hydrolysis of 1 has also been studied in the presence of glutathione (GSH).
Homopolymerization of Ethylene, 1-Hexene, Styrene and Copolymerization of Styrene With 1,3-Cyclohexadiene Using (h5-Tetramethylcyclopentadienyl)dimethylsilyl(N-Ar’)amido-TiCl2/MAO (Ar’=6-(2-(Diethylboryl)phenyl)pyrid-2-yl, Biphen-3-yl)
Authors: Camadanli Sebnem , Decker Ulrich , Kühnel Christa , Reinhardt Ingrid , Buchmeiser Michael R.
Published: January 2011

The propensity of a half-sandwich (η5-tetramethylcyclopentadienyl) dimethylsilylamido TiIV-based catalyst bearing an auxiliary diethylboryl-protected pyridyl moiety (Ti-8), activated by methylaluminoxane (MAO) to homopolymerize α-olefins such as ethylene, 1-hexene and styrene as well as to copolymerize styrene with 1,3-cyclo-hexadiene is described. The reactivity of Ti-8 was investigated in comparison to a 6-(2-(diethylboryl)phenyl)pyrid-2-yl-free analogue (Ti-3).
Terrestrial Laser Scanner Resolution: Numerical Simulations and Experiments on Spatial Sampling Optimization
Authors: Pesci Arianna , Teza Giordano , Bonali Elena
Published: January 2011

An empirical approach is proposed in order to evaluate the largest spot spacing allowing the appropriate resolution to recognize the required surface details in a terrestrial laser scanner (TLS) survey. The suitable combination of laser beam divergence and spot spacing for the effective scanning angular resolution has been studied by numerical simulation experiments with an artificial target taken from distances between 25 m and 100 m, and observations of real surfaces. The tests have been performed by using the Optech ILRIS-3D instrument. Results show that the discrimination of elements smaller than a third of the beam divergence (D) is not possible and that the ratio between the used spot-spacing (ss) and the element size (TS) is linearly related to the acquisition range. The zero and first order parameters of this linear trend are computed and used to solve for the maximum efficient ss at defined ranges for a defined TS. Despite the fact that the parameters are obtained for the Optech ILRIS-3D scanner case, and depend on its specific technical data and performances, the proposed method has general validity and it can be used to estimate the corresponding parameters for other instruments. The obtained results allow the optimization of a TLS survey in terms of acquisition time and surface details recognition.
Acute Response in vivo of a Fiber-Optic Sensor for Continuous Glucose Monitoring from Canine Studies on Point Accuracy
Authors: Liao Kuo-Chih , Chang Shih-Chieh , Chiu Cheng-Yang , Chou Yu-Hsiang
Published: January 2011

The objective of this study was to evaluate the acute response of SencilTM, a fiber-optic sensor, in point accuracy for glucose monitoring in vivo on healthy dogs under anesthesia. A total of four dogs with clinically normal glycemia were implanted with one sensor each in the chest region to measure the interstitial glucose concentration during the ovariohysterectomy procedure. The data was acquired every 10 seconds after initiation, and was compared to the concentration of venous plasma glucose sampled during the surgery procedures for accuracy of agreement analysis. In the four trials with a range of 71–297 mg/dL plasma glucose, the collected 21 pairs of ISF readings from the SencilTM and the plasma reference showed superior dispersion of residue values than the conventional system, and a linear correlation (the Pearson correlation coefficient is 0.9288 and the y-intercept is 14.22 mg/dL). The MAD (17.6 mg/dL) and RMAD (16.16%) of SencilTM measurements were in the comparable range of the conventional system. The Clarke error grid analysis indicated that 100% of the paired points were in the clinically acceptable zone A (61.9%) and B (38.1%).
Class Separation Improvements in Pixel Classification Using Colour Injection
Authors: Blanco Edward , Mazo Manuel , Bergasa Luis , Palazuelos Sira , Rodríguez Jose , Losada Cristina , Martín Jose
Published: January 2011

This paper presents an improvement in the colour image segmentation in the Hue Saturation (HS) sub-space. The authors propose to inject (add) a colour vector in the Red Green Blue (RGB) space to increase the class separation in the HS plane. The goal of the work is the development of an algorithm to obtain the optimal colour vector for injection that maximizes the separation between the classes in the HS plane. The chromatic Chrominace-1 Chrominance-2 sub-space (of the Luminance Chrominace-1 Chrominance-2 (YC1C2) space) is used to obtain the optimal vector to add. The proposal is applied on each frame of a colour image sequence in real-time. It has been tested in applications with reduced contrast between the colours of the background and the object, and particularly when the size of the object is very small in comparison with the size of the captured scene. Numerous tests have confirmed that this proposal improves the segmentation process, considerably reducing the effects of the variation of the light intensity of the scene. Several tests have been made in skin segmentation in applications for sign language recognition via computer vision, where an accurate segmentation of hands and face is required.
Reservoir Sedimentation and Flood Control: Using a Geographical Information System to Estimate Sediment Yield of the Songwe River Watershed in Malawi
Authors: Munthali Kondwani G. , Irvine Brian J. , Murayama Yuji
Published: January 2011

Severe watershed degradation continues to occur in the tropical regions of southern Africa. This has raised interest to harness and manipulate the potential of the watershed resources for human benefit as the populations grow. Songwe River is one such degrading watershed causing biennial flooding among other problems. In this study, climatic, land use, topographic and physiographic properties were assembled for this watershed and used in a process-based Geographical Information System (GIS) with the aim of determining the hydrological sediment potential of Songwe River watershed and quantifying possibilities of reservoir sedimentation. The study further aimed at determining the critical sediment generating areas for prioritized conservation management and the relationship between the increasing flood events in the floodplains and the rainfall trends. Based on hydrological runoff processes using the Pan-European Soil Erosion Risk Assessment (PESERA) model, the estimated amount of sediment transported downstream is potentially huge. Most of the sediment generation was established to be occurring in the upper sub-basin and specifically from built up village and degraded natural land. These trends have not only caused the increased flooding events in the lower sub-basin, but also pose a great sustainability risk of sedimentation to the proposed reservoir.
Core as a Novel Viral Target for Hepatitis C Drugs
Authors: Strosberg Arthur Donny , Kota Smitha , Takahashi Virginia , Snyder John K. , Mousseau Guillaume
Published: January 2011

Hepatitis C virus (HCV) infects over 130 million people worldwide and is a major cause of liver disease. No vaccine is available. Novel specific drugs for HCV are urgently required, since the standard-of-care treatment of pegylated interferon combined with ribavirin is poorly tolerated and cures less than half of the treated patients. Promising, effective direct-acting drugs currently in the clinic have been described for three of the ten potential HCV target proteins: NS3/NS4A protease, NS5B polymerase and NS5A, a regulatory phosphoprotein. We here present core, the viral capsid protein, as another attractive, non-enzymatic target, against which a new class of anti-HCV drugs can be raised. Core plays a major role in the virion’s formation, and interacts with several cellular proteins, some of which are involved in host defense mechanisms against the virus. This most conserved of all HCV proteins requires oligomerization to function as the organizer of viral particle assembly. Using core dimerization as the basis of transfer-of-energy screening assays, peptides and small molecules were identified which not only inhibit core-core interaction, but also block viral production in cell culture. Initial chemical optimization resulted in compounds active in single digit micromolar concentrations. Core inhibitors could be used in combination with other HCV drugs in order to provide novel treatments of Hepatitis C.
MODEL OF ACOUSTIC EMISSION SIGNAL AT THE PREVAILING MECHANISM OF COMPOSITE MATERIAL MECHANICAL DESTRUCTION
Authors: Filonenko Sergey , Nimchenko Tatiana , Kosmach Alexandr
Published: January 2011

A model of acoustic emission signal formation at the prevailing mechanism of the destruction of composite materials is considered. The results of acoustic emission signal modelling are presented, taking into account the variable velocity of loading change. Acoustic emission signal experimental research results corresponding to theoretical research results are considered in this paper. It is shown that irregularity of the trailing edge of the acoustic emission signal is influenced by the change in the rate of the destruction process in composites. Santrauka Išnagrinetas akustines emisijos signalo modelis su vyraujančiu kompozitiniu medžiagu irimo mechanizmu. Pateikti akustines emisijos signalu modeliavimo rezultatai, ivertinant skirtinga apkrovos pasikeitimo greiti. Taip pat pateikti eksperimentinio akustines emisijos signalu tyrimo rezultatai, kurie sutampa su teoriniais tyrimais. Parodyta, kad akustines emisijos signalo galinio fronto netolygumas atsiranda tuomet, kai kinta kompozitines medžiagos irimo greitis.
METHODOLOGICAL ASPECTS OF AERONAUTICAL SYSTEM UPGRADE
Authors: Samkov Alexei , Suslova Galyna , Litvinenko Vladimir , Zakharchenko Yurii
Published: January 2011

This article is devoted to the methodological aspects of upgrading aircraft, including the complex of mathematical methods, algorithms and criteria which allow the objective of the assigned research problem to be met.

Santrauka

Šiame straipsnyje nagrinejami metodologiniai orlaiviu modernizavimo aspektai, iskaitant matematiniu metodu, algoritmu ir kriteriju kompleksa, kuris leidžia priimti tam tikra mokslini sprendima.
Geology, Miette, Alberta
Authors: Mountjoy E W
Published: January 2011

Miette map-area (NTS 83 F/4) includes parts of the Rocky Mountain Foothills and Front Ranges subdivisions of the Central Canadian Rocky Mountains. A major part of this scenic map-area is located in northeastern Jasper National Park. The bedrock geology consists
of Lower to Upper Paleozoic carbonate-dominated strata of the Front Ranges, with Mesozoic clastic strata characterizing the Foothills. Geologic structure features broad folds and classic superimposed thrust duplexes involving multiple detachments in both the westernmost Foothills and the easternmost
Front ranges. Noteworthy is the occurrence, within the Miette and McConnell thrust sheets, of east-dipping thrust fault slices, which are unusual structures formed by backward rotation of parts of the thrust masses. The map-area also contains the Miette Reef Complex, a Devonian-aged carbonate reef
and its enveloping clastic strata. Although the original field work was conducted in the late 1950s using tent camps, horses and foot traverses as the major means of access, the map-area was revisited many times over the period 1958-2004 by the late Professor Eric W. Mountjoy, Ph.D., F.R.S.C.,
author of the map, and his students and colleagues. This additional field work elucidated both geological structures and the stratigraphy and origin of the Miette Reef Complex, a well-exposed example of the prolific petroleum-bearing Devonian reefs of the subsurface of the Western Canada Sedimentary
Basin. A preliminary series map of this area was published in 1960 as map 40-1969. This digital version, Map 2158A, includes observations and cross-sections which reflect additional field and air photographic studies by Dr. Mountjoy, as well as contributions by colleagues D. Lebel and R.A. Price in
recent years.
A review of the anthropogenic influence on biogenic secondary organic aerosol
Authors: Hoyle C. R. , Boy M. , Donahue N. M. , Fry J. L. , Glasius M. , Guenther A. , Hallar A. G. , Huff Hartz K. , Petters M. D. , Petäjä T. , Rosenoern T. , Sullivan A. P.
Published: January 2011

Abstract. Because of the climate and air quality effects of organic aerosol, it is important to quantify the influence of anthropogenic emissions on the aerosol burden, both globally and regionally, and both in terms of mass and number. Methods exist with which the fractions of organic aerosol resulting directly from anthropogenic and biogenic processes can be estimated. However, anthropogenic emissions can also lead to an enhancement in secondary organic aerosol formation from naturally emitted precursors. We term this enhanced biogenic secondary organic aerosol (eBSOA). Here, we review the mechanisms through which such an effect may occur in the atmosphere and describe a work flow via which it may be quantified, using existing measurement techniques. An examination of published data reveals support for the existence of the enhancement effect.
Mid-latitude Summer Nighttime Anomaly (MSNA) – observations and model simulations
Authors: Thampi S. V. , Balan N. , Lin C. , Liu H. , Yamamoto M.
Published: January 2011

Abstract. In this paper, we present model simulations of the Mid-latitude Summer Nighttime Anomaly (MSNA) in the Northern Hemisphere, which is characterized by noon-time dip and evening maximum in the diurnal variation of the ionospheric density. The simulations are carried out using SUPIM (Sheffield University Plasmasphere Ionosphere Model) for solar minimum at 135° E longitude where MSNA is most pronounced in the Northern Hemisphere. The simulations are used to understand the relative importance of electric fields, and zonal and meridional winds in the formation of MSNA. The wind velocities measured by the Middle and Upper atmosphere radar (MU radar) and those obtained from the horizontal wind model (HWM93) are used. The results show that the formation of MSNA is closely related to the diurnal variation of the neutral winds with little contribution from the changes in the electric fields. The observed features of MSNA are better reproduced when MU radar winds are used as model input rather than HWM winds.
Hydroclimatology of Lake Victoria region using hydrologic model and satellite remote sensing data
Authors: Khan S. I. , Adhikari P. , Hong Y. , Vergara H. , F Adler R. , Policelli F. , Irwin D. , Korme T. , Okello L.
Published: January 2011

Abstract. Study of hydro-climatology at a range of temporal scales is important in understanding and ultimately mitigating the potential severe impacts of hydrological extreme events such as floods and droughts. Using daily in-situ data over the last two decades combined with the recently available multiple-years satellite remote sensing data, we analyzed and simulated, with a distributed hydrologic model, the hydro-climatology in Nzoia, one of the major contributing sub-basins of Lake Victoria in the East African highlands. The basin, with a semi arid climate, has no sustained base flow contribution to Lake Victoria. The short spell of high discharge showed that rain is the prime cause of floods in the basin. There is only a marginal increase in annual mean discharge over the last 21 years. The 2-, 5- and 10- year peak discharges, for the entire study period showed that more years since the mid 1990's have had high peak discharges despite having relatively less annual rain. The study also presents the hydrologic model calibration and validation results over the Nzoia basin. The spatiotemporal variability of the water cycle components were quantified using a hydrologic model, with in-situ and multi-satellite remote sensing datasets. The model is calibrated using daily observed discharge data for the period between 1985 and 1999, for which model performance is estimated with a Nash Sutcliffe Efficiency (NSCE) of 0.87 and 0.23% bias. The model validation showed an error metrics with NSCE of 0.65 and 1.04% bias. Moreover, the hydrologic capability of satellite precipitation (TRMM-3B42 V6) is evaluated. In terms of reconstruction of the water cycle components the spatial distribution and time series of modeling results for precipitation and runoff showed considerable agreement with the monthly model runoff estimates and gauge observations. Runoff values responded to precipitation events that occurred across the catchment during the wet season from March to early June. The spatially distributed model inputs, states, and outputs, were found to be useful for understanding the hydrologic behavior at the catchment scale. The monthly peak runoff is observed in the months of April, May and November. The analysis revealed a linear relationship between rainfall and runoff for both wet and dry seasons. Satellite precipitation forcing data showed the potential to be used not only for the investigation of water balance but also for addressing issues pertaining to sustainability of the resources at the catchment scale.
A coupled remote sensing and the Surface Energy Balance with Topography Algorithm (SEBTA) to estimate actual evapotranspiration over heterogeneous terrain
Authors: Gao Z. Q. , Liu C. S. , Gao W. , Chang N.-B.
Published: January 2011

Abstract. Evapotranspiration (ET) may be used as an ecological indicator to address the ecosystem complexity. The accurate measurement of ET is of great significance for studying environmental sustainability, global climate changes, and biodiversity. Remote sensing technologies are capable of monitoring both energy and water fluxes on the surface of the Earth. With this advancement, existing models, such as SEBAL, S_SEBI and SEBS, enable us to estimate the regional ET with limited temporal and spatial coverage in the study areas. This paper extends the existing modeling efforts with the inclusion of new components for ET estimation at different temporal and spatial scales under heterogeneous terrain with varying elevations, slopes and aspects. Following a coupled remote sensing and surface energy balance approach, this study emphasizes the structure and function of the Surface Energy Balance with Topography Algorithm (SEBTA). With the aid of the elevation and landscape information, such as slope and aspect parameters derived from the digital elevation model (DEM), and the vegetation cover derived from satellite images, the SEBTA can account for the dynamic impacts of heterogeneous terrain and changing land cover with some varying kinetic parameters (i.e., roughness and zero-plane displacement). Besides, the dry and wet pixels can be recognized automatically and dynamically in image processing thereby making the SEBTA more sensitive to derive the sensible heat flux for ET estimation. To prove the application potential, the SEBTA was carried out to present the robust estimates of 24 h solar radiation over time, which leads to the smooth simulation of the ET over seasons in northern China where the regional climate and vegetation cover in different seasons compound the ET calculations. The SEBTA was validated by the measured data at the ground level. During validation, it shows that the consistency index reached 0.92 and the correlation coefficient was 0.87.
Acetone
Authors: Howard William L.
Published: January 2011

Acetone is the simplest and most important of the ketones. It is a colorless, mobile, flammable liquid with a mildly pungent, somewhat aromatic odor, and is miscible in all proportions with water and most organic solvents. Most of the world's manufactured acetone is obtained as a coproduct in the process for phenol from cumene. The remainder comes from dehydrogenation of isopropyl alcohol, although this process is declining. Acetone is an excellent solvent for a wide range of gums, waxes, resins, fats, grease, oils, dyestuff, and cellulosics. It is used as a carrier for acetylene, in the manufacture of a variety of coatings and plastics, and as a raw material for the chemical synthesis of a wide range of products such as ketene, methyl methacrylate., bisphenol A, diacetone alcohol, methyl isobutyl ketone, hexylene glycol, and isophorone. Numerous natural sources of acetone make it a normal consitutent of the environment. It is readily biodegradable.
Introduction to Rare‐Event Simulation
Authors: Shortle John F. , L'Ecuyer Pierre
Published: January 2011

Without special techniques, simulation of rare events can be prohibitive due to the large amount of computer time needed. This article gives an introduction to methods that can be used to substantially reduce the variance associated with simulating rare events. Two broad classes of methods are discussed—importance sampling and splitting.
Air Traffic Management
Authors: Hoffman Robert , Mukherjee Avijit , Vossen Thomas W. M.
Published: January 2011

The objective of air traffic management is to mitigate imbalances between the demand for air traffic services and the capacity of the air transportation system, so as to ensure that aircraft can flow through the airspace safely and efficiently. This article outlines the principal optimization models that have been proposed to provide decision support within air traffic management, and describes the trade‐offs and challenges that arise in this environment.
Asymptotic Behavior of Discrete‐Time
M
arkov Chains
Authors: Tekin Eylem
Published: January 2011

This article summarizes the theoretical foundations for analyzing the asymptotic behavior of discrete‐time Markov chains (DTMC). Consider a system that evolves randomly over time. Let
X

n

denote the state of the system at time
n
 = 0, 1, … . If, for all
n
 ≥ 0, the future probability distribution of the system depends only on the current state and is independent of the past, the stochastic process {
X

n

,
n
 ≥ 0} is called a
DTMC
. In this article, we study the distribution of
X

n

as
n
 → ∞. We first introduce several concepts for classifying the states of a DTMC. These concepts include irreducibility, periodicity, recurrence, and transience. Using these concepts, we next describe the necessary and sufficient conditions for the existence and uniqueness of a limiting distribution, and explain how to compute a limiting distribution, if it exists.
Axiomatic Measures of Risk and Risk‐Value Models
Authors: Jia Jianmin , Dyer James S. , Butler John C.
Published: January 2011

This article provides a review of risk and risk‐value models that lead to decision making by explicitly trading off between risk and value. We begin with a discussion of a preference‐dependent measure of risk that is compatible with traditional expected utility theory, and therefore lends itself to an examination of how individuals perceive risky gambles as well as how they choose among them. Further, this risk measure can be the basis for generalizing models of decision making based on the intuitively appealing notion of trading off between risk and value. Based on the two‐attribute expected utility axioms, this risk‐value framework has much more flexibility in modeling preferences than the traditional single‐attribute expected utility theory. Specifically, we describe three useful classes of decision models: moments risk‐value models, exponential risk‐value models, and generalized disappointment models. These decision models unify two streams of research: one in developing preference models and the other in modeling risk judgments. They can also provide prescriptive guidance for those people who are willing to deviate from the traditional expected utility preference models and make their decisions based on risk‐value trade‐offs, as in financial decision making.
Network Theory: Concepts and Applications
Authors: Garcia‐Diaz Alberto , Phillips Don T. , Hicks Illya
Published: January 2011

This article summarizes fundamental concepts, definitions, notations and formulations of network‐flow models, and illustrates their applicability. We focus on deterministic network‐flow models of frequent use to solve significant problems in business and industry. Each topic is introduced, mathematically defined, and illustrated by means of an example. The applications presented can be classified into two broad categories. The first category includes applications where the solution is achieved by selecting a chain or cycle that optimizes a suitable objective function. Each arc is interpreted as a directed link that allows the movement of one unit of flow from the start node to the end node of the arc. The arc parameter or
length
is a generic cost of using the arc. Usually, these models are referred to as
distance networks.
In the second category, a more general interpretation of an arc is used, namely, that of a channel used for shipping multiple units of flow. The arc parameter represents the maximum amount of flow per unit time that can be shipped along the arc at any time. This parameter is called the
capacity
of the arc, and the network models are referred to as
capacitated flow network
s.
Batch Markovian Arrival Processes (BMAP)
Authors: Cordeiro James D. , Kharoufeh Jeffrey P.
Published: January 2011

This article describes the batch Markovian arrival process (BMAP), a point process that is characterized by Markov‐modulated batch arrivals of random size. The BMAP is a generalization of many well‐known processes including the Markovian arrival process (MAP), the Poisson process, and the Markov‐modulated Poisson process. It provides a common framework for modeling arrival processes in a variety of applications. We formally define the continuous‐ and discrete‐time BMAP, review a few basic results for each, and show how these processes generalize many common point processes. Additionally, we provide suggestions for further reading on the subject.
Behavioral Operations: Applications in Supply Chain Management
Authors: Donohue Karen , Siemsen Enno
Published: January 2011

Behavioral operations is a field within operations management that studies human behavior in the context of operations. The discipline uses a variety of research methodologies including behavioral modeling, controlled experiments, and field studies to identify and understand relevant aspects of human behavior in operational contexts. This article gives a brief overview of behavioral operations and its recent applications in the subfield of supply chain management.
Branch and Cut
Authors: Mitchell John E.
Published: January 2011

The performance of branch‐and‐bound methods for integer programming problems has been dramatically improved by incorporating cutting planes. The resulting technique is known asbranch‐and‐cut. Cutting planes are inequalities that can be used to improve the linear programming relaxation of an integer programming problem. They are added as required, at the root node and also elsewhere in the tree. Problem‐specific cutting planes have been developed for many classes of problems. Recently, there has been a great interest in improving and refining general classes of cutting planes, including, for example, Gomory cuts. Branch‐and‐cut algorithms can exploit parallel computers and multicore architecture in a natural way. Branch‐and‐cut has also been applied to mixed‐integer nonlinear programming problems.
The Bulgarian Operational Research Society
Authors: Yanev Nicola
Published: January 2011

The article provides information about Bulgarian Operational Research Society (BORS) to interested members of the general public. BORS is registered as a scientific not‐for‐profit association on November 2, 1992 and is a member of the International Federation of Operational Research Societies (IFORS) and the European Association of Operational Research Societies (EURO) since 1994.
B
yelorussian
O
perational
R
esearch
S
ociety (
By
ORS
)
Authors: Gordon Valery S. , Guschinsky Nikolai N.
Published: January 2011

The history, milestones, objectives and main activities of the Byelorussian Operational Research Society (ByORS) are presented. The ByORS is a non‐profit scientific organization which supports application and promotes development of operations research (OR) methods in Republic of Belarus. It unites the experts in the field of operations research, applied mathematics, mathematical economy, and their applications. The ByORS also represents Belarus in the international network of experts in the field of operations research such as the Association of European Operational Research Societies (EURO) and the International Federation of Operational Research Societies (IFORS).
Central Path and Barrier Algorithms for Linear Optimization
Authors: Roos Kees
Published: January 2011

In this article, the main ideas underlying the modern interior‐point methods are presented. We discuss primal, dual, and primal‐dual methods and show that each of these methods can be used to solve a linear optimization problem in polynomial time. It is made clear that the central path plays a crucial role in each of the methods. The described methods require a starting point on or close to the central path. Given such a point, a variant of Newton's method can be used to construct a numerical procedure that generates a sequence of iterates that converges to an optimal solution of the problem.
C
hinese Postman Problem
Authors: Yu Wanyan , Batta Rajan
Published: January 2011

This article describes one of the classical routing problems—Chinese postman problem (CPP). The objective of CPP is to determine a closed walk of minimum length covering each arc on the graph at least once. Five types of CPP based on the properties of graphs are discussed: Undirected CPP, directed CPP, mixed CPP, windy postman problem (WPP), and hierarchical postman problem (HPP). The first two types of problems are polynomially solvable while the other three are proved to be NP‐hard. Available mathematical models and algorithms are summarized for each problem type. This article also presents some variations of the CPP and recent results from the literature.
Maximum Clique, Maximum Independent Set, and Graph Coloring Problems
Authors: Pattillo Jeff , Butenko Sergiy
Published: January 2011

This article introduces the closely related maximum clique, maximum independent set, graph coloring, and minimum clique partitioning problems. The survey includes some of the most important results concerning these problems, including their computational complexity, known bounds, mathematical programming formulations, and exact and heuristic algorithms to solve them.
Coherent Systems
Authors: Neath Ronald C. , Neath Andrew A.
Published: January 2011

Asystemis a collection ofcomponents, each of which is either working or in failure; in turn the system itself is either working or in failure. A system is said to becoherentif each working component is beneficial to the system. In this entry, the reader is introduced to some properties of coherent systems.
Combinatorial Auctions
Authors: Porter David , Rassenti Stephen
Published: January 2011

There are many issues that must be faced when designing an auction which involves multiple resources that must be simultaneously allocated when information concerning values for the various possible combined uses and constraints faced by the potential users is decentralized. This article examines various auction formats used to allocate resources in these combinatorial settings. While there is some consensus on the use of iterative combinatorial clock auctions for these types of allocation problems, many specific implementation issues are still open questions.
Communicating Decision Information to the Lay Risk Manager: A Consultant's Perspective
Authors: Brown Rex
Published: January 2011

This article reports the personal reflections of an experienced consultant on how to communicate decision‐related information to risk managers. The aim is to help them to make up their minds on an immediate or repetitive choice, to justify their actions to others, or to gather more information first. The information includes prescriptive decision analyses, factual risk assessments, value judgments, raw data, or personal observations. The communication may use the information alone or combine it with other available information. Also addressed are the role of decider judgment, layman language, macromodels, interactive communication, and assessment firmness. The author's perspective is based on 50 years of consulting to a variety of deciders and on two research projects.
Contributions to Software Reliability withORApplications
Authors: Kapur P.K. , Kumar Ravi , Gupta Anshu
Published: January 2011

Computing systems finds application in every sphere of human life. Almost everything we see around us in this world seems to be driven by the computing systems. It has made it necessary for the software developer to lay special emphasis on the quality of the software. Quality in the field of software industry means having a right balance between reliability, development time, and cost. The wealth of research in reliability modeling and applications is remarkable, which confirms its continuing importance as a research topic.

Among the various kind of reliability modeling, non‐homogeneous Poisson process (NHPP)‐based software reliability modeling has been a topic of most practical and academic interest. This article emphasizes on highlighting the research in the NHPP‐based software reliability growth modeling (SRGM), development of unified schemes for the same which makes the study of SRGMs and their application on any specific testing process much easier, and operational research applications of SRGMs in two decision‐making problems related to the software development, namely, software release time problem and resource allocation at unit testing level.
Cooperative Games with Transferable Utility
Authors: Wilson Jennifer
Published: January 2011

Here, we introduce the concept of a cooperative game with transferable utility and analyze the relationship between cooperative and noncooperative games. We discuss properties of cooperative games and illustrate them with several classes of well‐known games including market games, cost allocation games, and simple games. We also discuss the assumptions behind games with transferable utility and compare them to games without transferable utility. Finally, we mention briefly a number of solution concepts for cooperative games and summarize recent extensions of cooperative game theory.
Customized Price Responses to Bid Opportunities in Competitive Markets
Authors: Ferguson Mark
Published: January 2011

Traditional price optimization involves the use of historical price/demand data to measure the percentage change in demand for a given percentage change in the product's price. This science is not useful in analyzing many business‐to‐business transactions, however, because, instead of receiving some portion of the total demand for a given price, suppliers are often faced with a winner‐take‐all opportunity bidding opportunity. In such cases, the historical price/demand data consists of the set of bidding opportunities, some possible attributes of the customer requesting for the bid, the price submitted by the supplier, and whether the bid opportunity was won or lost. In this article, we describe how price optimization techniques can be applied to this setting.
Delayed Renewal Processes
Authors: Argon Nilay Tanik
Published: January 2011

One of the underlying assumptions for a renewal process is that the first renewal takes place at time zero. There may be several applications where this assumption is not satisfied by a stochastic process that would otherwise be a renewal process. In this article, the properties of such stochastic processes, also called
delayed renewal processes
are discussed and it is observed that these processes possess almost all the properties of standard renewal processes.
Dual Simplex
Authors: Banciu Mihai
Published: January 2011

The dual simplex algorithm is an attractive alternative method for solving linear programming problems. Since the addition of new constraints to a problem typically breaks primal feasibility but not dual feasibility, the dual simplex can be deployed for rapid reoptimization, without the need of finding new primal basic feasible solutions. This is especially useful in integer programming, where the use of cutting plane techniques require the introduction of new constraints at various stages of the branch‐and‐bound/cut/price algorithms. In this article, we give a detailed synopsis of the dual simplex method, including its history and relationship to the primal simplex algorithm, as well as its properties, implementation challenges, and applications.
Dynamic Auctions
Authors: Bergemann Dirk , Said Maher
Published: January 2011

We survey the recent literature on designing auctions and mechanisms for dynamic settings. We distinguish between two broad class of settings: those with a dynamic population of agents, whose private information remains fixed throughout time; and those with a fixed population of agents, whose private information changes across time. Within each of these settings, we discuss both efficient (welfare‐maximizing) and optimal (revenue‐maximizing) mechanisms.
Dynamic Pricing Under Consumer Reference‐Price Effects
Authors: Arslan Hasan , Kachani Soulaymane
Published: January 2011

In this article, we explore the current‐state of literature on how dynamic pricing models incorporate consumer reference‐price effects in developing more informed dynamic pricing strategies for products that have repeated consumer interactions. We first examine the literature on how consumer demand is impacted by reference‐price effects and how consumers form reference prices through their purchase experience. We then explore, in detail, the dynamic pricing models with consumer reference‐price effects in major studies, in order to highlight their key findings and insights. We conclude our review by pointing out research gaps and future research directions on dynamic pricing area in the presence of consumer reference‐price effects.
Dynamic Vehicle Routing
Authors: Thomas Barrett W.
Published: January 2011

This article provides an introduction to dynamic vehicle routing. Dynamic vehicle routing has grown in importance in the last decade as computing and mobile information technology have made it possible for companies to improve routing through real‐time information. Despite these advances, dynamic routing still poses significant computational challenges. This article focuses on the methods that researches have devised to overcome these computational challenges. Three common solution structures are identified: a priori, insertion, and unrestricted. Solutions methodologies are also distinguished by whether or not they incorporate information about future events.
Forecasting: State‐Space Models and Kalman Filter Estimation
Authors: Gürsoy Kemal , Baykal‐Gürsoy Melike
Published: January 2011

We present continuous and discrete time linear state‐space models and explain the Kalman filter algorithm that is used to obtain the one‐step‐ahead state estimations recursively. Adaptive and nonlinear state estimations, as well as parameter estimation, with a Kalman filter are also briefly described.
Foundations of Decision Theory
Authors: Cox Louis Anthony
Published: January 2011

Although many specific normative decision models and techniques for improving or optimizing decisions have been proposed, most decision‐analytic methods rest on a simple, common conceptual foundation. The basic elements are aset of possible alternativesthat the decision maker must choose among; aset of statesthat may also affect the consequences of the choice; and aconsequence setof different, nonindifferent, possible outcomes that the decision maker cares about. Decision analysis helps the decision maker use beliefs about states and preferences for consequences to identify preferred choices or decisions in the opportunity set. This article discusses these foundations and how they can be applied and extended to support difficult decisions.
Instance Formats for Mathematical Optimization Models
Authors: Gassmann Horand , Ma Jun , Martin Kipp
Published: January 2011

In order to use a piece of software—optimization solver, simulation package, model analyzer, and so on—on a mathematical model, it is necessary to communicate a model instance to the software. Additionally, such software typically accepts options to specify tolerances, set algorithmic parameters, and so on. Finally, the software must communicate the result instance back to the user. In this article we focus on optimization solvers and review existing formats for optimization instances, solver option instances and result instances, and describe the research issues involved in designing these instance formats.
Introduction to Branching Processes
Authors: Jagers Peter
Published: January 2011

An overview of branching process theory, its background, history, and applications is given. Different forms of branching processes are described, from the simple Galton–Watson scheme to general processes.
Campaign Analysis: An Introductory Review
Authors: Kline Jeffrey , Hughes Wayne , Otte Douglas
Published: January 2011

Using analytical methods to derive insights into military operational planning is as old as the 2500 year writings of Sun Tzu. Broad in nature, campaign analysis is a field of application, rather than a focused academic discipline. In this introductory review we define and introduce a process for campaign analysis, illustrate where analysis has been informative in past campaigns, discuss how it is used today, and how it is evolving for future military planners. We summarize by highlighting that although campaign analysis uses tools from operations research, systems analysis, and the social sciences, its value is judged solely on its ability to provide the commander with timely, useful, and measurable information to guide decisions. It can supplement, but never replace military judgment.
Just‐In‐Time/Lean Production Systems
Authors: Benton W.C.
Published: January 2011

Just‐In‐Time (JIT) production systems have been successfully implemented in numerous companies throughout the world. JIT manufacturing is a philosophy based on eliminating waste, reducing manufacturing cost, and promoting total quality control. The primary objective of JIT is to produce the right quantity of product in the right place at the right time, while maintaining minimal work‐in‐process and minimal stock of completed work. In JIT production systems, little or no finished product is kept in stock. Rather than producing goods and supplying customers from stock, JIT production systems focus on producing exactly the amount required at exactly the time the customer requires the product.

JIT is also referred to as lean production. An organization driven by a JIT philosophy can improve profits and return on investment by reducing inventory levels, reducing variability, improving product quality, reducing production and delivery lead times, and reducing setup costs. With JIT (Lean) the entire manufacturing system, from purchasing to shop floor management, can be measured and controlled. Therefore, the JIT (Lean) system is a powerful management tool that could easily determine the success or failure of the manufacturing system.
Limit Theorems for Branching Processes
Authors: Jagers Peter , Sagitov Serik
Published: January 2011

The long–range behavior of branching processes is described with an emphasis on one hand and on simple Galton‐Watson processes on the other, on general branching processes.