How can a retailer identify the dominant strategy in a newsvendor situation with a supplier take‐it‐or‐leave‐it offer?

In this paper, we investigate how a retailer facing the newsvendor situation with a supplier take‐it‐or‐leave‐it offer can identify the dominant strategy. In our newsvendor setting, (a) the supplier, as the dominant player, imposes a take‐it‐or‐leave‐it offer with quantity discounts; (b) the retailer, as the dominated player who also has her own discount scheme for customers to promote sales, should then determine whether she accepts the supplier's offer; and (c) neither player has complete information about the probability distribution of demand. By examining only the price schedules of both players, we establish the conditions under which the retailer can safely accept the take‐it‐or‐leave‐it offer such that the strategy to abandon her own discount policy in favor of the quantity discounts offered by the supplier dominates the strategy to continue her own discount policy without the quantity discounts offered by the supplier.     

Was Three Mile Island a ‘Normal Accident’?

Perrow’s normal accident theory suggests that some major accidents are inevitable for technological reasons. An alternative approach explains major accidents as resulting from management failures, particularly in relation to the communication of information. This latter theory has been shown to be applicable to a wide variety of disasters. By contrast, Perrow’s theory seems to be applicable to relatively few accidents, the exemplar case being the Three Mile Island nuclear power station accident in the U.S. in 1979. This article re‐examines Three Mile Island. It shows that this was not a normal accident in Perrow’s sense and is readily explicable in terms of management failures. The article also notes that Perrow’s theory is motivated by a desire to shift blame away from front line operators and that the alternative approach does this equally well.     

H<Subscript>2</Subscript>S nano-jetting through a p–n junction-like graphene/Au nano-injector: a molecular dynamics study

This paper uses fully atomistic molecular dynamics to outline the dynamics of H₂S nano-jetting through a p–n junction-like graphene/Au nano-injector. We examined the effects of nano-injector diameter (d), system temperature (T), and the extrusion velocity (v) of a graphite piston plate on the formation of H₂S nano-jets, system pressure, and the number of molecules (N _m) in the outflow. The combined effects of high critical pressure and small orifice resulted in a larger jet angle, which increased the number of H₂S molecules stuck to the graphene surface at the outlet. Moving the graphite piston plate toward the orifice of the nano-injector increased in the change in momentum and interactive forces between H₂S molecules, resulting in three phases of pressure establishment in the nano-injector: incubation (phase I), steep pressure increase (phase II), and high pressure (phase III). When operated at T ≥ 300 K and v < 27.912 m/s, the proposed nano-jet device is able to produce a well-dispersed spray of H₂S without H₂S molecules sticking to the graphene surface at the outlet. The p–n junction-like Au-doped graphene surface provides an additional energy barrier preventing the transport of electrons from H₂S molecule to the graphene. This inhibits the accumulation of H₂S molecules and subsequent blockages at the exit of the nano-injector. Simulation results demonstrate the potential of using chemiresistive sensing to monitor H₂S flow patterns during nano-jetting. The findings presented in this study could be transformative to the design of nano-injectors for other gases commonly used as biomarkers.     

Synthesis of a Multi-Connected Digital Controller for a Robotized Vibration Isolation Platform Based on <Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript>-Optimization

We consider the problem of constructing multi-connected control of a robotic platform designed to protect technological objects and human operators from low-frequency influences on part of the moving base. The platform includes six drive mechanisms with stepper motors. The problem is solved by the methods of the modern theory of robust stabilization and optimal control based on H_∞-optimization in the state space. We construct a mathematical model of the multidimensional system, taking into account the characteristics of electromechanical drives and using signals of feedback sensors as state variables. We give an example of synthesizing a multidimensional optimal stabilizing controller in the form of state feedback for a system with disturbances bounded in L₂-norm. We define the feedback control structure and obtain the matrix of feedback coefficients. We also show the results of mathematical modeling.     

Building a marine cadastral information system for the United States — a case study

Depleted marine resources and increased threats by man-made pollutants are forcing many countries to increase law enforcement and begin offshore planning. Accurate, useable, and accessible digital boundaries, with defined territorial claims, are becoming essential for daily business in the ocean. The term cadastre has not often been used in the context of the marine environment, though many (and some may argue all) of the cadastral components such as adjudication, survey, and owner rights have a parallel condition in the ocean. This paper discusses some of the framework issues that must be considered in the development of marine cadastral data and the use of these data in a marine information system for the United States. The unique features of coastal and marine data, the policy framework that surrounds the development of these data, and the implications to state¹, national, and international policy are discussed. In addition, a specific case study, the Ocean Planning Information System is outlined as a “real world” application where these cadastral data have been applied toward integrated ocean planning and governance.     

What is a “Good” Encoding of Guarded Choice?

The π-calculus with synchronous output and mixed-guarded choices is strictly more expressive than the π-calculus with asynchronous output and no choice. This result was recently proved by C. Palamidessi and, as a corollary, she showed that there is no fully compositional encoding from the former into the latter that preserves divergence-freedom and symmetries. This paper argues that there are nevertheless “good” encodings between these calculi. In detail, we present a series of encodings for languages with (1) input-guarded choice, (2) both input- and output-guarded choice, and (3) mixed-guarded choice, and investigate them with respect to compositionality and divergence-freedom. The first and second encoding satisfy all of the above criteria, but various “good” candidates for the third encoding—inspired by an existing distributed implementation—invalidate one or the other criterion. While essentially confirming Palamidessi's result, our study suggests that the combination of strong compositionality and divergence-freedom is too strong for more practical purposes.     

Robust sliding mode-<Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> control approach for a class of nonlinear systems affected by unmatched uncertainties using a poly-quadratic Lyapunov function

This paper proposes a robust sliding mode-H _∞ control design methodology for a class of nonlinear systems with unmatched parametric uncertainty and external disturbance. The design procedure combines the high robustness of the sliding mode control (SMC) with the H _∞ norm performance. First, based on linear matrix inequalities (LMI) technique and multiple Lyapunov functions approach, the sliding surface design problem is formulated as a H _∞ state-feedback control for a reduced uncertain nonlinear system with polytopic representation. Then, a sliding mode controller that drives the system states to the sliding surface in finite time and maintains a sliding mode is constructed. Finally, a comparative study is done to prove the effectiveness of the results.     

Board’s IQ: What makes a board smart?

The amount of investment that has been made in interactive whiteboards (IWB) in the Turkish educational system during the past several years is quite striking. This investment is part of a plan to integrate information and communication technologies (ICT) into the Turkish educational system, with the goal of increasing the qualitative and quantitative aspects of schooling. Prior to IWB investments, hundreds of thousands of computers, projectors, and printers were distributed to schools in efforts to raise a generation able to respond to the demands of the 21st century. In addition, 98% of secondary school students and 93% of primary school students were provided with Internet access via ADSL. The aim of this study is to analyze the emerging trend of smart board investment in Turkish primary and secondary schools, with consideration of problems that hinder the effective use of IWBs in classrooms as compared to previous ICT integration efforts by the Ministry of National Education. The research is designed as an evaluative case study. The required data are collected through online questionnaires, teacher and pupil interviews, and document searches from teachers and students from various Turkish primary and secondary schools. It is not surprising that the factors hindering the use of IWBs in education are similar to the inhibiting factors in previous ICT integration projects. The findings show that when the needs for in-service training, digital education materials, support, maintenance, and administration are not addressed, educational ICT is unlikely to deliver the expected results.     

What the <0.70, 1.17, 0.99, 1.07> is a Symbol?

The notion of a ‘symbol’ plays an important role in the disciplines of Philosophy, Psychology, Computer Science, and Cognitive Science. However, there is comparatively little agreement on how this notion is to be understood, either between disciplines, or even within particular disciplines. This paper does not attempt to defend some putatively ‘correct’ version of the concept of a ‘symbol.’ Rather, some terminological conventions are suggested, some constraints are proposed and a taxonomy of the kinds of issue that give rise to disagreement is articulated. The goal here is to provide something like a ‘geography’ of the various notions of ‘symbol’ that have appeared in the various literatures, so as to highlight the key issues and to permit the focusing of attention upon the important dimensions. In particular, the relationship between ‘tokens’ and ‘symbols’ is addressed. The issue of designation is discussed in some detail. The distinction between simple and complex symbols is clarified and an apparently necessary condition for a system to be potentially symbol, or token bearing, is introduced.     

Flow of CO<Subscript>2</Subscript>–ethanol and of CO<Subscript>2</Subscript>–methanol in a non-adiabatic microfluidic T-junction at high pressures

In this work, an experimental investigation of the single- and multiphase flows of two sets of fluids, CO₂–ethanol and CO₂–methanol, in a non-adiabatic microfluidic T-junction is presented. The operating conditions ranged from 7 to 18 MPa, and from 294 to 474 K. The feed mass fraction of CO₂ in the mixtures was 0.95 and 0.87, respectively. Under these operating conditions, CO₂ was either in liquid, gas or supercritical state; and the mixtures experienced a miscible single phase or a vapour–liquid equilibrium (VLE), with two separated phases. Taylor, annular and wavy were the two-phase flow regimes obtained in the VLE region. In the single phase region, the observed flows were classified into standard single-phase flows, “pseudo” two-phase flows and local phenomena in the T-junction. Flow regime maps were generated, based on temperature and pressure conditions. Two-phase flow void fractions and several parameters of Taylor flow were analysed. They showed a clear dependency on temperature, but were mostly insensitive to pressure. A continuous accumulation of liquid, either in the CO₂ channel or at the CO₂-side wall after the T-junction, disturbed most of the experiments in VLE conditions by randomly generating liquid plugs. This phenomenon is analysed, and capillary and wetting effects due to local Marangoni stresses are suggested as possible causes.     

A GRASP × ELS approach for the job-shop with a web service paradigm packaging

The Job-Shop Scheduling Problem (JSSP) is well known for its complexity as an NP-hard disjunctive scheduling problem. The problem addressed in this paper is JSSPs with an objective of minimizing makespan while satisfying a number of hard constraints. An efficient GRASP × ELS approach is introduced for solving this problem. The efficiency is evaluated using the widely known 40 Laurence’s instances which encompass medium and large scale instances. The computational results prove that the proposed method competes with the best published methods in both quality of results and computational time. Recently, Web services have generated great interest in researchers. Such application architecture is based on the client–server model using existing Internet protocols and open standards. It provides new approaches to optimization methods. The proposed GRASP × ELS is packaged into a Web Service (WS), i.e., it offers for the research community an open access to our optimization approach. Moreover, the proposed web service can be even included in research future works with a very small programming effort.To favor utilization of the web service and to prove the facility in which the service could be used, we provide an example in Java proving that it is possible to obtain in less than 10 min a client application using the different methods exposed by this web service. Such usage extends to classical library inclusion in program with the difference that a method is called in the client side and represents an execution on the server.The Web Service paradigm is a new approach in spreading algorithms and therefore this paper stands at the crossroads of optimization research community and the web service community expectations. The GRASP × ELS provided in the web service, is a state of the art method which competes with previously published ones and which has the advantage of being available for free, in any languages, everywhere contributing in spreading operational research contribution.     

Land administration and cadastral trends — a framework for re-engineering

This paper reviews the need for a new land administration vision that takes a more integrated approach rather than the historic fragmented approach and examines change management of land administration and cadastral systems in the context of global drivers of change. This results in the development of a framework for re-engineering land administration systems. After discussing a land administration vision the paper reviews trends and issues in the context of this framework. While the paper discusses global issues and trends, the paper concentrates on the experiences and ongoing land administration research of the authors' and their colleagues with a focus on Australia.     

<Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> suboptimal tracking controller design for a class of nonlinear systems

In this paper, a new technique is proposed to solve the H _∞ tracking problem for a broad class of nonlinear systems. Towards this end, based on a discounted cost function, a nonlinear two-player zero-sum differential (NTPZSD) game is defined. Then, the problem is converted to another NTPZSD game without any discount factor in its corresponding cost function. A state-dependent Riccati equation (SDRE) technique is applied to the latter NTPZSD game in order to find its approximate solution which leads to obtain a feedback-feedforward control law for the original game. It is proved that the tracking error between the system state and its desired trajectory converges asymptotically to zero under mild conditions on the discount factor. The proposed H _∞ tracking controller is applied to two nonlinear systems (the Vander Pol’s oscillator and the insulin-glucose regulatory system of type I diabetic patients). Simulation results demonstrate that the proposed H _∞ tracking controller is so effective to solve the problem of tracking time-varying desired trajectories in nonlinear dynamical systems.     

The <Emphasis Type="Italic">k</Emphasis>-Homotopic Thinning and a Torus-Like Digital Image in <Emphasis Type="Bold">Z</Emphasis><Superscript><Emphasis Type="Italic">n</Emphasis></Superscript>

In order to discuss digital topological properties of a digital image (X,k), many recent papers have used the digital fundamental group and several digital topological invariants such as the k-linking number, the k-topological number, and so forth. Owing to some difficulties of an establishment of the multiplicative property of the digital fundamental group, a k-homotopic thinning method can be essentially used in calculating the digital fundamental group of a digital product with k-adjacency. More precisely, let be a simple closed k _i -curve with l _i elements in . For some k-adjacency of the digital product which is a torus-like set, proceeding with the k-homotopic thinning of , we obtain its k-homotopic thinning set denoted by DT _k . Writing an algorithm for calculating the digital fundamental group of , we investigate the k-fundamental group of by the use of various properties of a digital covering (Z×Z,p ₁×p ₂,DT _k ), a strong k-deformation retract, and algebraic topological tools. Finally, we find the pseudo-multiplicative property (contrary to the multiplicative property) of the digital fundamental group. This property can be used in classifying digital images from the view points of both digital k-homotopy theory and mathematical morphology.

Multicriteria Robust Generalized <Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript> and γ<Subscript>0</Subscript> Controllers with Application to Stabilization of a Rotor in Electromagnetic Bearings

For linear plants with unstructured or structured uncertainty of bounded norm, this paper designs Pareto optimal robust controllers in terms of linear matrix inequalities in multicriteria control problems with the generalized H₂ or γ₀ norms. The controller design procedure is based on optimization of a scalar objective function (Germeier convolution) and semi-definite programming. The developed theory is used to design multicriteria robust controllers in the stabilization problem for a rotor in electromagnetic bearings.     

Algorithms for solving a class of problems of <Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript>-optimization of control systems

Problems of synthesis of feedbacks providing H _∞-norm-maximal suppression of disturbances, acting on a linear stationary SISO system with account of limitedness of control resources, are considered. Two methods for solving are proposed. The first one is based on the Nevanlinna-Pick interpolation, and the second one is constructed on the ground of guaranteeing singularities of controllers. Within the framework of these approaches, simple computation algorithms that do not require solving Riccati equations or linear matrix inequalities are generated. The application of the developed algorithms is illustrated by an example.     

Mixed <Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript>/<Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> control for a class of nonlinear networked control systems

In this paper, the mixed H ₂/H _∞ control problem is investigated for a class of nonlinear discrete-time networked control systems with random network-induced delays, stochastic packet dropouts and probabilistic sensor faults. The packet dropouts process is modeled as a homogeneous Markov chains taking values in a finite state space. Network-induced delays occur in a random way with known upper bound. A set of stochastic variables are exploited to describe sensor faults with different probabilistic density functions. By using a delay-dependent Lyapunov functional, a mode-dependent mixed H ₂/H _∞ controller is designed to guarantee both stochastic stability of the closed-loop system and the prescribed H2, H¥ control performances. Sufficient conditions for the existence of the mixed H ₂/H _∞ controller are presented in terms of a series of LMIs. If these LMIs are feasible, then the modedependent mixed H ₂/H _∞ controller can be obtained. A numerical example is given to demonstrate the effectiveness of the developed method.     

What Is Context <Emphasis Type="Italic">For</Emphasis>? <Emphasis Type="Italic">Syntax in a Non-Abstract World</Emphasis>

An explanation for the uncertain progress of formalist linguistics is sought in an examination of the concept of syntax. The idea of analyzing language formally was made possible by developments in 20th century logic. It has been pointed out by many that the analogy between natural language and a formal system may be imperfect, but the objection made here is that the very concept of syntax, when applied to any non-abstract system of communication, is flawed as it is commonly used. Syntax is properly defined with respect to an individual transformation rule that might be applied to some message. Collections of syntax rules, however, are inevitably due to categories imposed by an observer, and do not correspond to functional features found in non-abstract systems. As such, these categories should not be relied upon as aids to understanding any natural system.