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We present and generalize the basic ideas underlying recent work aimed at the construction of mutually unbiased bases in finite dimensional Hilbert spaces with the help of group and graph theoretical concepts. In this approach finite groups are used to construct maximal sets of mutually unbiased bases. Thus the prime number restrictions of previous approaches are circumvented and this construction principle sheds new light onto the intricate relation between mutually unbiased bases and characteristic geometrical structures of Hilbert spaces.

Measles is a highly contagious disease. A 24 years old patient, recently exposed to measles (unvaccinated), presented in the emergency department with severe agitation, compatible with an acute psychotic episode, during the measles epidemic which spread in Israel in 2018–2019. Upon hospital admission, strict isolation was instructed, yet, without compliance, probably due to the patient’s status. Measles diagnosis was promptly confirmed. As measles transmission was eminent, public health measures were employed through immediate implementation of the section 15 of the Public Health Ordinance, allowing for compulsory short-term isolation. The patient’s condition improved within a few days and the measures were no longer necessary. This measles case occurred in the pre-Coronavirus disease 2019 (COVID-19) epidemic when use of a Public Health Ordinance was considered an extreme measure. This is in contrast to the current global use of Public Health laws to enforce strict quarantine and isolation on persons infected or potentially exposed to COVID-19. Nevertheless, minimizing infectious diseases transmission is a core function of public health law. Utilizing legal enforcement in circumstances of immediate public health hazard, such as nosocomial measles transmission, necessitates careful consideration. The integrative clinical and public health approach and prompt measures employed in this exceptional case, led to prevention of further infection spread.

The logical place to put view-related logic is... inside your view, right? "A little logic here... a little logic there..." but all of a sudden we hardly recognize our views. A quick glance through our code and we can't tell our Ruby apart from our HTML. Don't worry; this is a fun opportunity for some refactoring! Come see several approaches you can start using today to clean up your views.

This article examines the suburbanization of poverty in metropolitan areas with a particular focus on the experience of the United States. The discussion highlights key trends and likely causes of suburban poverty and provides an overview of various attempts to classify heterogeneity across suburbs. We believe the trends and consequences observed in the United States are relevant to a broad host of global settings, some of which have been struggling with high rates of suburban poverty for some time. The article closes by identifying gaps in current knowledge related to the suburbanization of poverty and highlighting the implications of the suburbanization of poverty for safety net policy.

This paper introduces a graphical method for valuing options on real asset investments that allow the investor to switch between different operating modes at a single point-in-time. The technique uses mixtures of truncated exponential functions to approximate both the probability density function for project value and the expressions for option value of each alternative. The distribution for project value is transformed into an expected cash flow function for the option under each mode of operation. After determining an optimal exercise strategy, these functions are used to determine the option value. The graphical method allows the option exercise strategy to be communicated effectively through a graphical representation of the expected cash flow functions. A comparison of this approach to the existing binomial lattice method is presented. The efficiency of the graphical method is comparable to the binomial lattice and in some cases accurate solutions can be obtained with less CPU time.

The purpose of the study is the development and application of a methodology for evaluating the economic and environmental effects of various policies for the management of the Texas Coastal Zone. The specific goals of the study are: (1) the establishment of operating criteria which are specific to the Texas Coastal Zone; (2) the development of a methodology or systematic approach for evaluating the economic and environmental effects of alternative policies for Texas Coastal Zone management, and (3) the testing of the systematic approach by the application of several hypothetical management policies to a specific region of the Texas Coastal Zone.

The estimation of urban and regional travel patterns has been a necessary part of current efforts to establish land use guidelines for the Texas coastal zone. Emerging from this research are several theoretical and computational advances relating to the gravity model of spatial interaction. The paper details computational experience with travel estimation within Corpus Christi, Texas, using a new convex programming approach of Charnes, Raike and Bettinger. It is found that available estimation techniques necessarily result in non-integer solutions. A mathematical device is therefore introduced which assures integer-values estimates. Implications and extensions of the work are indicated.

We determine the affine equivalence classes of the eight variable degree three homogeneous bent functions using a new algorithm. Our algorithm applies to general bent functions and can systematically determine the automorphism groups. We provide a partial verification of the enumeration of eight variable degree three homogeneous bent functions obtained by Meng et al. We determine the affine equivalence classes of these functions.

As momentum grows for a sustainable urbanisation goal in the post-2015 development agenda, this paper reports on an action research study that sought to tackle the urban health divide by enabling intersectoral action on social determinants at the local level. The study was located in the cities of Mombasa in Kenya and Valparaiso in Chile, and the impact of the intervention on child nutrition was evaluated using a controlled design. The findings showed that an action research process using the social educational process known as PLA could effectively build the capacity of multisectoral teams to take coordinated action which in turn built the capacity of communities to sustain them. The impact on child nutrition was inconclusive and needed to be interpreted within the context of economic collapse in the intervention area. Four factors were found to have been crucial for creating the enabling environment for effective intersectoral action (i) supportive government policy (ii) broad participation and capacity building (iii) involving policy makers as advisors and establishing the credibility of the research and (iii) strengthening community action. If lessons learned from this study can be adapted and applied in other contexts then they could have a significant economic and societal impact on health and nutrition equity in informal urban settlements.

We propose two new classes of hash functions which are motivated by Maximum Rank Distance (MRD) codes. We analise the security of these schemes. The system setup phase is computationally expensive for general field extensions. To overcome this limitation we derive an algebraic solution which avoids computations in special extension fields in the intended operational range of the hash functions.

When determining order quantity, logistics managers can choose between ordering the Economic Order quantity (EOQ) or a Quick Response (QR) quantity. QR is a general term that collectively describes several rapid-replenishment inventory methods such as Just-In-Time or Continuous Replenishment. The QR order quantity is defined as the minimum inventory needed to support operations until the next delivery. The EOQ and the QR methods are substantially different because the EOQ minimizes the joint cost of ordering and holding inventory whereas the QR method minimizes only the cost of holding inventory. The goals of this research are to compare the costs of the two methods and to propose rules that help managers select the more appropriate method to use in specific situations.

The main goal of this paper is to describe a new multistage Monte Carlo (MMC) simulation method for solving influence diagrams using local computation. Global methods have been proposed by others that sample from the joint probability distribution of all the variables in the influence diagram. However, for influence diagrams having many variables, the state space of all variables grows exponentially, and the sample sizes required for good estimates may be too large to be practical. In this paper, we develop a MMC method, which samples only a small set of chance variables for each decision node in the influence diagram. MMC is akin to methods developed for exact solution of influence diagrams in that we limit the number of chance variables sampled at any time. Because influence diagrams model each chance variable with a conditional probability distribution, the MMC method lends itself well to influence diagram representations.

Real Options Analysis (ROA) provides a framework for valuing reactive and proactive managerial flexibility in investment decisions. Estimating the volatility parameter for a real options model is challenging because there are typically no historical returns for the underlying asset and no current market prices. A previously developed method of using simulation to estimate the volatility parameter for a real investment is demonstrated. The effects of serial price correlation and price-demand cross-correlation on volatility parameters developed with this method are explained. Finally, managerial implications of these findings are discussed.

Financial Accounting Standard (FAS) 133 requires business entities to document their anticipation of hedge effectiveness in order to qualify for hedge accounting treatment of gains and losses from financial derivatives. In the absence of specific guidelines, the accounting industry has espoused the “80–125” rule for determining hedge effectiveness. But the authors observe that meaningful assessment of anticipated hedge effectiveness must consider two distinct aspects of a firm's hedging strategy: (1) the strength of the hedging relationship, which is determined by the choice of the hedging instrument; and (2) the position taken in the hedging instrument relative to the holdings of the hedged item. They take both aspects of hedging into consideration in developing alternative measures of hedge effectiveness and distinguishing between the potential and attained effectiveness of a particular hedge. This approach enables the user to evaluate the relative merits of alternative hedging strategies to support risk management decisions, and also to document a selected hedging strategy's anticipated effectiveness for purposes of compliance with FAS 133. While the authors endorse a fairly broad interpretation of hedge effectiveness, their approach can also be used in the narrower context of an “80–125” rule.

We present the theory and construction of a new class of designs, which we call SEEDs (spontaneous emission error designs), arising in the study of decay processes of certain quantum systems used in the newly emerging field of quantum computing. We show that there is a simple and surprising connection between subspaces of the system Hilbert space, stable against these quantum jumps and the incidence matrices of SEEDs.

Every merger and acquisition deal presents a different goal and a different mix of critical issues to manage. Making, consummating, and integrating a deal puts pressure on chief executives to play multiple leadership roles and switch quickly from one role to another throughout the merger process. The roles employed vary dramatically with the type of deal and how ambitious the strategy. As the rationales for transactions have changed, new challenges have evolved, especially for those leading the deals: leaders must establish and communicate the strategic vision for the merger ‐‐ they need to explain the top four or five sources of value in the deal and what the core values and culture of the new organization should be; leaders must cheer on the stakeholders to generate enthusiasm for the merger or acquisition, and to confront fear and uncertainty in its various forms; leaders must close the deal; leaders captain change by managing the integration of the two entities; and leaders crusade for the new entity. These five roles are essential to all transactions, but leaders need to employ each at different times. The strategic rationale behind the deal, and the inherent risks and opportunities that it presents, determines which roles a leader needs to play and when.

The classical McEliece scheme for combined encryption and coding is based on error-correcting codes. We study a variation where codes are replaced by lattices. Dealing with continuous rather than discrete signals eliminates most classical attacks. Decoding a lattice is known to be NP-complete and an universal decoding algorithm is discussed in low dimensions (≤ 100). Classes of lattices with polynomial time decoding algorithms are explored. Further, by replacing decoding by complete decoding, a scheme is obtained which combines signature and quantizing.

In a traditional anti-jamming system a transmitter who wants to send a signal to a single receiver spreads the signal power over a wide frequency spectrum with the aim of stopping a jammer from blocking the transmission. In this paper, we consider the case that there are multiple receivers and the transmitter wants to broadcast a message to all receivers such that colluding groups of receivers cannot jam the reception of any other receiver. We propose efficient coding methods that achieve this goal and link this problem to well-known problems in combinatorics. We also link a generalisation of this problem to the Key Distribution Pattern problem studied in combinatorial cryptography.

The Colorado legislature recently funded a grant proposal to create “Prospector,” a regional library network. The network, now operational, was a joint project of the University of Northern Colorado and the Colorado Alliance of Research Libraries. The major goals of the project were (1) to create a single digital catalog of the library holdings of the major academic and public library collections in Colorado and make it accessible by anyone from anywhere in the state; and (2) to create an automated borrowing system to facilitate the ability of library patrons to order library materials from home, school, office, or at a local library and arrange for expedited delivery to various locations. This article describes the issues faced and the experiences involved in bringing these goals to fruition.

Many companies in the biotechnology industry have significant valuations despite having no product revenue because their products are in early stages of development. In the past 10–15 years, investors have bid up the stock prices of companies showing promise of developing a blockbuster drug. We explain the decision-tree method and binomial-lattice method (which adds a growth option) and use them to value a biotechnology company, Agouron Pharmaceuticals, as the sum of the values of its drug-development projects. The growth option was added because the development of an initial new molecular entity (NME) is similar to purchasing a call option on the value of a subsequent NME. We compare our computed values of Agouron with actual market values at selected points in time during the development of Agouron's Viracept, a drug used to treat HIV-positive patients.

In this article we outline a computer assisted classification of the ovoids in an orthogonal space of the type Ω + (8,5).

Using isomorphism invariants, we enumerate the translation planes of order 49 and determine their automorphism groups.

Consideramos um modelo de reabastecimento de estoque com revisão periódica junto a uma doutrina operacional encomende-até-R para o caso de prazos determinísticos de reposição e um processo de demanda estocástica com covariância estacionária. Derivamos um método para fixar o estoque de segurança a fim de obter a probabilidade da falta de estoque desejada quando a função de autocovariância de uma demanda Gaussiana é conhecida. Dado que o método não requer que modelos paramétricos de séries temporais sejam ajustados aos dados, ele é facilmente posto em prática. Ademais, o método tem se mostrado assimptoticamente válido quando a função de autocovariância da demanda é estimada com dados históricos. Os efeitos dos vários níveis de demanda autocorrelacionada no índice de falta de estoque são demonstrados em situações em que a autocorrelação de demanda é ignorada ou desconhecida pelo gerente de estoque. Similarmente, os efeitos no nível de estoque de segurança são demonstrados para vários níveis de autocorrelação.We consider a periodic-review inventory replenishment model with an order-up-to-R operating doctrine for the case of deterministic lead times and a covariance-stationary stochastic demand process. A method is derived for setting the inventory safety stock to achieve an exact desired stockout probability when the autocovariance function for Gaussian demand is known. Because the method does not require that parametric time-series models be fit to the data, it is easily implemented in practice. Moreover, the method is shown to be asymptoticaly valid when the autocovariance function of demand is estimated from historical data. The effects on the stockout rate of various levels of autocorrelated demand are demonstrated for situations in which autocorrelation in demand goes undetected or is ignored by the inventory manager. Similarly, the changes to the required level of safety stock are demonstrated for varying levels of autocorrelation.

Cone ratio DEA (Data Envelopment Analysis) models are suggested for monitoring and/or early warning systems to be used by bank regulatory agencies. Illustrative examples are developed from data on 1984 and 1985 performances of the 16 largest banks in Texas. Five large non-Texas banks are introduced as “excellent performers” to help evaluate these Texas banks in terms of their “risk coverage” as well as “efficiency”. Cone ratio envelopment areused to tarnsform original data in order to reflect performances by the non-Texas banks with respect to “risk coverage” as well as “efficiency”. Formulas for transforming to and from the original data are supplied with accompanying explanations and interpretations which include comparisons with the “risk-adjusted capital” and “risk-coverage” allowances formulas that have been adopted recently by U.S. Government (and other) regulators in banking (and insurance) in conformance with the “Basel Agreement” of 1988.

We use queueing network models to show that with other factors held constant, the transformation of a functional into a cellular layout causes average work-inprocess levels to increase because of a loss in routeing flexibility resulting from the dedication of machines to part families. However, in practice cellular layouts provide important benefits to counteract this loss in routeing flexibility. We use deterministic models to investigate the potential benefits of four characteristics of cellular layouts: (1) operations overlapping, (2) setup time reduction, (3) reductions in move times, and (4) the simultaneous setup of all equipment in a cell. Stochastic operating environments are investigated with simulation models, which provide evidence that these four characteristics will o ffset the reduced routeing flexibility in practice. In addition, the models show that as the congestion level increases, the need also increases to o ffset this loss in routeing flexibility.

The last decade of the millennium saw a Hamlet boom unmatched since the onset of American mass media. The prince who in Shakespeare’s play literally ends up nowhere (dying in a state that is neither quite Denmark nor Norway) now walks everywhere among us, a ghost in mass culture, from light comedies or adventure movies like L.A. Story and Last Action Hero to venues as ambitious as Branagh’s bombastic 1996 film version.1 The play has always been a rich reserve of Shakespearean sound bites and cliches. But this alone does not tell us much about why Hamlet in particular has enjoyed such a startling re-emergence into popular prominence. The same figure whose failure to inherit and refusal to take the throne in Denmark lead to the death of his state has somehow become (perhaps on the basis of this refusal) the unofficial legislator of latetwentieth-century democratic man – the man who would, and would not, be king. What Bartleby the Scrivener was to the man in the gray flannel suit, Hamlet has become to the Range-Rover set.

A new technique for assessing the sensitivity and stability of efficiency classifications in Data Envelopment Analysis (DEA) is presented. Here developed for the ratio (CCR) model, this technique extends easily to other DEA variants. An organization's input-outut vector serves as the center for a cell within which the organization's classification remains unchanged under perturbations of the data. For the l 1, l ∞ and generalized l ∞ norms, the radius of the maximal cell can be computed using linear programming formulations. This radius can be interpreted as a measure of the classification's stability, especially with respect to errors in the data.

Air-transport demand forecasting constitutes an important determinant of airport planning, design, and operations. Errors in forecasting can be very costly. Underestimating demand may lead to increased congestion, delay, and inadequate airport facilities. Overestimating demand may also create serious economic problems for airport authorities. It is, therefore, very important for airport planners to develop reliable forecasting models and to understand possible limitations in the forecasting accuracy of these models. The objective of this paper is to examine the predicting ability and forecasting accuracy of air-travel demand models. In particular, an analytical framework for developing econometric models is presented and postfact analysis is used to test the accuracy of the models. Statistical data describing air-travel demand patterns for two major international airports, the Frankfurt and the Miami International Airports, are used to demonstrate the effectiveness of the proposed models. In addition, the effect of external factors such as the deregulation of the air-transport industry is examined. The results suggest that simple models with few independent variables perform as well as more complicated and costly models, and that external factors have a pronounced effect on air-travel demand.

Previous studies of (parametric) aggregate frontiers have attempted to capture stochastic features of the random variables (i.e. inputs and outputs) by assuming a ‘risk’ situation (where the probability distributions of the random variables are known). The purpose of this paper is to present and test a new method invented by Charnes, Semple, Song and Thomas for the usual situations of uncertainty (where the probability distributions of the random variables involved in the technical inefficiencies are unknown) to build up global efficient production functions in the context of operations in the Latin American airline industry. This method develops an empirical efficient production function via a ‘Robustly Efficient Parametric Frontier’ (REPF) in a two-stage approach. As in the Charnes et al. development using a Multiplicative-DEA model, the marginal tradeoffs of the efficient production function are immediately available instead of being harassed by discontinuities of derivatives and numerical instabilities.

We consider a periodic-review inventory replenishment model with an order-up-to-R operating doctrine for the case of deterministic lead times and a covariance-stationary stochastic demand process. A method is derived for setting the inventory safety stock to achieve an exact desired stockout probability when the autocovariance function for Gaussian demand is known. Because the method does not require that parametric time-series models be fit to the data, it is easily implemented in practice. Moreover, the method is shown to be asymptotically valid when the autocovariance function of demand is estimated from historical data. The effects on the stockout rate of various levels of autocorrelated demand are demonstrated for situations in which autocorrelation in demand goes undetected or is ignored by the inventory manager. Similarly, the changes to the required level of safety stock are demonstrated for varying levels of autocorrelation.