Guaranteed Level Research Articles

Very high energy optical depth of the universe

The propagation of very energetic gamma-rays at GeV–TeV energies over cosmological distances is mainly affected by pair-production on the soft background photon field. The resulting energy dependent absorption is sensitive to the level of background photon field present along the line of sight as well as to possible modifications of the pair-production process. In this study, we focus on the latter aspect by fixing the absorption to the guaranteed level by invoking a minimum model for the background photon field. The result of the study suggests (at the level of 4.2 standard deviations) that the intrinsic spectra (after correction for absorption) show a significant upturn at the transition from optically thin to optically thick. The observation is not explained by known systematic effects related to the instrument (e.g. energy scale, spectral bias). By construction, neither the intrinsic source spectra nor the background photon field can be responsible for the observed effect unless either an un-realistic fine-tuning of the sources or a substantially lower level of the background light below the guaranteed level is realized in nature. We conclude, that the origin of the observed effect is most likely related to an anomaly of the pair-production process similar to the effect predicted in the case of a pseudo-scalar (axion-like) field.

Resource allocation for OFDM relay systems with statistical QoS guarantees

SUMMARYBy integrating the concept of effective capacity, we propose the resource allocation schemes for subcarrier‐pair based OFDM decode‐and‐forward and amplify‐and‐forward relay systems for quality‐of‐service (QoS) guarantees. The objective is to maximize the system throughput subject to a given statistical delay QoS constraint. First, we pair the subcarriers over the source‐relay channel and the relay‐destination channel by the descending order of the subcarriers' channel gains. Second, by making use of the derived equivalent end‐to‐end channel gains of the subcarrier pairs, we apply joint water‐filling power allocation over the subcarrier pairs and then partition the power of the subcarrier pairs between the source and the relay. We prove that as the equivalent end‐to‐end channel gains of the subcarrier pairs are given, the combination of sorted subcarrier pairing and joint water‐filling power allocation is jointly optimal to maximize the effective capacity. The simulation results show that our proposed schemes achieve the highest effective capacity for OFDM decode‐and‐forward and amplify‐and‐forward relay systems as compared with other existing schemes. The results also verify that our proposed schemes can efficiently provide different levels of delay QoS guarantees, even if under the stringent delay QoS constraints. Copyright © 2012 John Wiley & Sons, Ltd.

Related-party transactions and corporate governance: The evidence from the Taiwan stock market

In this study we explore how corporate governance affects the level of related-party transactions (RPTs) and how it moderates the motives of using RPTs in Taiwan, an ownership-concentrated economy. The empirical results show that good corporate governance is effective in constraining RPTs with the negative relation being sustainable across different measures of RPTs (raw, residual and industry-adjusted RPTs) and across different types of RPTs (related sales, lending and guarantee, and related borrowings). The propping-up hypothesis indicates that the level of related sales is positively correlated with the condition that firms plan to issue seasoned equity next period and the condition of a decrease in the reported earnings. The internal capital market hypothesis indicates that the level of related lending and guarantee (related borrowing) is negatively (positively) correlated with the condition of an increase in capital expenditure and an increase in net working capital. The empirical results lend partial support to the two hypotheses. More importantly, we find that corporate governance moderates the relation between the motives and the level of RPTs.

On the Optimal Type and Level of Guarantees for Prospect Theory Investors

On the Optimal Type and Level of Guarantees for Prospect Theory Investors

On the Optimal Type and Level of Guarantees for Prospect Theory Investors

It is well known that cumulative prospect theory (CPT) can explain a demand for guarantees in investment products. This observation motivates us to study what type of guarantee observed in real–world insurance markets is most attractive to CPT investors. We find that CPT investors favor a simple terminal wealth guarantee compared to more complex ratchet and cliquet guarantees. To obtain this result we determine the optimal specifications of these contracts to CPT investors by means of an extensive simulation study. Optimization further allows to study the desired guarantee level (which is determined endogeneously from preferences), and illustrates what elements of CPT drive the demand for guarantees. CPT investors either desire a guarantee level equal to their reference point or insurance against large losses only. Such a crash insurance can be explained by probability weighting alone, i.e., even in the absence of loss aversion.

Fault Detection and Isolation of Electrical Induction Motors via LPV Fault Observers

In this paper we present an application to an electrical induction motor of a recently proposed gain-scheduling Fault Detection and Isolation (FDI) filter design method for LPV systems. Starting from a detailed nonlinear mathematical representation of the motor it is shown how, based on a judicious convex interpolation of a family of linearized models, a quasi-LPV approximation can be achieved and used for synthesizing the LPV-FDI filter. The latter is then synthesized by ensuring guaranteed levels of disturbance rejection and fault detection and isolation sensitivity. The resulting diagnostic filter is gain-scheduled and uses a set of motor variables, assumed measurable on-line, as a scheduling vector. The effectiveness of the LPV-FDI framework is illustrated by a numerical example.

When does a royalty clause with a guarantee lead to a no-equilibrium situation in a licensing contract?

We consider a licensing agreement where a brand owner grants to a manufacturer the rights to use his own brand on the goods she produces. The ‘royalty’ clause requires that the licensee pays a monetary compensation for having such property and it generally consists of a percentage of the licensee's sales. Furthermore, a guaranteed minimum royalty, the so-called guarantee, is also required, and it has to be paid even in the face of total failure of the property. We take into account such clause by considering a non-differentiable term—the maximum between the guarantee and the percentage of the sales—in the payoffs of the involved parts. A Stackelberg game constituted by two non-differentiable optimal control problems is formulated in order to find the Stackelberg equilibrium open-loop advertising strategies for the licensor and the licensee. We discuss the existence conditions for such an equilibrium with respect to feasible guarantee levels, and we highlight that particular guarantee values lead to a no-equilibrium situations. Copyright © 2011 John Wiley & Sons, Ltd.

Design of structured dynamic output-feedback controllers for interconnected systems

We address the design of structured controllers for networks of interconnected multivariable discrete-time subsystems. Different from existing approaches, where the structure of the controller is fixed a priori, we aim to design decentralised controllers such that each subsystem has a controller, which may not only use the output of its own associated subsystem, but also selected outputs of other subsystems. The total number of all those additional outputs used is to be minimised, while satisfying a guaranteed level of ℋ∞-performance. For the resulting non-convex optimisation problem, we first present a novel characterisation of the ℋ∞-performance of the closed-loop system by means of a system augmentation approach. Then, stimulated from compressive sensing theory, we propose a weighted ℓ1-minimisation to relax the ℓ0 objective function for structure optimisation. We develop an algorithm to deal with the relaxed decentralisation control problem, where the controller is obtained by iteratively solving convex optimisation problems. In addition, an iterative algorithm is developed to optimise the initial values such that the solvability of the decentralised control problem is further improved. Finally, an example is given to show the effectiveness of the proposed approaches.

Service guarantee and optimal payout models

Abstract This paper evaluates both the optimal service level and optimal economic payout in service payout models. A service guarantee level is explicitly taken into consideration to obtain the optimal payout. In this study, we consider a generic model to provide insights into the dynamic interaction between the service guarantee and optimal payout levels. Parametric analyses show that when the demand payout coefficient is high, the impact of the payout is positive only if the payout rate is high enough.

Formal Verification of Numerical Programs: From C Annotated Programs to Mechanical Proofs

Numerical programs may require a high level of guarantee. This can be achieved by applying formal methods, such as machine-checked proofs. But these tools handle mathematical theorems while we are interested in C code, in which numerical computations are performed using floating-point arithmetic, whereas proof tools typically handle exact real arithmetic. To achieve this high level of confidence on C programs, we use a chain of tools: Frama-C, its Jessie plugin, Why and provers among Coq, Gappa, Alt-Ergo, CVC3 and Z3. This approach requires the C program to be annotated: each function must be precisely specified, and we prove the correctness of the program by proving both that it meets its specifications and that no runtime error may occur. The purpose of this paper is to illustrate, on various examples, the features of this approach.

The Contradictions of the State Policy on Regulation of Prices on Medicines: Problems and Ways of Their Solving

The article analyzes the existing model of regulation of prices on medicines in the Russian Federation. Problems of this model are described (especially the fact that it stimulates elimination of cheaper medicines from the product range of pharmacies and pharmaceutical distributors and hinders investments into local development of innovative medicines). Ways to solve these problems are proposed. It is demonstrated that all medicines should be divided into three groups according to their price, and for each group a special method of price regulation should be used. It is also proposed to implement a guaranteed level of profitability of local developers of innovative medicines.

Robust optimal control of time-delay systems based on Razumikhin theorem

This paper presents an optimal control approach for the general robust control design problem of linear time delay systems, which considers parameter uncertainties as well as state delay. It is shown that the robust control problem can be transformed into an optimal control problem with the amouof plant uncertainties involved in the performance index. A stability criterion has been developed under which the uncertain dynamical system can not only achieve stability, but also acquire the guaranteed level of performance for regulation. A suitable linear state feedback control law is also characterized via Lyapunov stability theory to ensure performance robustness of the closed-loop system. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society

Equity-linked pension schemes with guarantees

This paper analyses the relationship between the level of a return guarantee in an equity-linked pension scheme and the proportion of an investor’s contribution needed to finance this guarantee. Three types of schemes are considered: investment guarantee, contribution guarantee and surplus participation. The evaluation of each scheme involves pricing an Asian option, for which relatively tight upper and lower bounds can be calculated in a numerically efficient manner. We find a negative (and for two contract specifications also concave) relationship between the participation in the surplus return of the investment strategy and the guarantee level in terms of a minimum rate of return. Furthermore, the introduction of the possibility of early termination of the contract (e.g. due to the death of the investor) has no qualitative and very little quantitative impact on this relationship.

Qualidade nutricional de rações secas para cães adultos comercializadas em Rio Verde – GO

Foi avaliada a qualidade nutricional de rações secas para cães adultos e verificou-se se as informações nos rótulos estavam de acordo com a legislação e com as análises laboratoriais e se o consumo sugerido supria as exigências nutricionais de cães adultos. Foram adquiridas e analisadas amostras de 18 rações comerciais, oito do tipo econômico e 10 premium. Quanto à conformidade com o rótulo, somente 12,5 e 10% (umidade), 87,5 e 70% (PB), 25 e 20% (EEHA), 0 e 0% (MM), 12,5 e 40% (Ca) e 0 e 20% (P) das rações econômicas e premium, respectivamente, estavam conformes. Quanto aos níveis de garantia, a maioria das rações apresentou níveis dentro dos limites. O consumo médio diário sugerido de ração premium foi 13,07% menor, os consumos de PB e de P foram 10 e 16,87% maiores e os consumos de Ca e EM foram 16,27 e 11,15% menores comparado com o consumo de ração econômica. Concluiu-se que as rações secas para cães adultos, vendidas em Rio Verde, são de boa qualidade já que atendem os limites exigidos pela legislação, há deficiências na rotulagem em relação aos níveis de garantia e há excesso no fornecimento diário de energia com o uso de rações econômicas.

Analysis of rounded exponential data

The problem of inference based on a rounded random sample from the exponential distribution is treated. The main results are given by an explicit expression for the maximum-likelihood estimator, a confidence interval with a guaranteed level of confidence, and a conjugate class of distributions for Bayesian analysis. These results are exemplified on two concrete examples. The large and increasing body of results on the topic of grouped data has been mostly focused on the effect on the estimators. The methods and results for the derivation of confidence intervals here are hence of some general theoretical value as a model approach for other parametric models. The Bayesian credibility interval recommended in cases with a lack of other prior information follows by letting the prior equal the inverted exponential with a scale equal to one divided by the resolution. It is shown that this corresponds to the standard non-informative prior for the scale in the case of non-rounded data. For cases with the absence of explicit prior information it is argued that the inverted exponential prior with a scale given by the resolution is a reasonable choice for more general digitized scale families also.

Guaranteed Quality of Service in Multimedia System

Guaranteed quality of service (QoS) and aggregate data throughput is needed for a variety of applications ranging from real-time data collection to multimedia applications. This paper presents a novel design and implementation technique called QoS and aggregate data throughput scheduling model (QTT) which solves the availability bandwidth and aggregate throughput problems in resource reservation system. The QTT is composed of batch generation module (BGM) and PEM. The BGM selects requests from reservation queue and places them in a batch. The PEM schedules requests in each batch to achieve the maximal aggregate throughput while providing a given level of QoS guarantees. The experimental results indicate that our scheduling model achieves remarkable aggregate throughput under a given level of QoS guarantees.

Changing flights in mid-air

Continuous queries can run for unpredictably long periods of time. During their lifetime, these queries may need to be adapted either due to changes in application semantics (e.g., the implementation of a new alert detection policy), or due to changes in the system’s behavior (e.g., adapting performance to a changing load). While in previous works query modification has been implicitly utilized to serve specific purposes (e.g., load management), to date no research has been done that defines a general-purpose, reliable, and efficiently implementable model for modifying continuous queries at run-time. In this report, we introduce a punctuation-based framework that can formally express arbitrary lifecycle operations on the basis of input-output mappings and basic control elements such as start or stop of queries. On top of this foundation, we derive all possible query change methods, each providing different levels of correctness guarantees and performance. We further show how these models can be efficiently realized in a state-of-the-art stream processing engine; we also provide experimental results demonstrating the key performance tradeoffs of the change methods.

Investment guarantees in unit-linked life insurance from the customer perspective

Interest rate guarantees are a typical contract feature in unit-linked-life insurance products. As the financial crisis of 2007/2008 has shown, these guarantees can be of substantial value for policyholders since they ensure that at least a minimum amount will be paid back even if the mutual fund value falls below a specific guaranteed level. However, from the insurance company’s view, these guarantees can be costly—especially in highly volatile markets—due to the required risk management measures which must be undertaken to secure the guarantees promised to the customers. Thus, the aim of this paper is to investigate whether customers really value these guarantees and if their willingness to pay (WTP) is sufficient to cover the guarantee costs. To elicit customer WTP, we use an online questionnaire and compare these results to the actual guarantee costs calculated with the Black and Scholes option pricing formula. One main finding is that even though most of the participants in the online questionnaire work in the financial industry, subjective prices are difficult to derive and are lower, on average, than the prices obtained using a financial pricing model. However, many participants are still willing to pay a substantially higher price.

The Determinants of Mortgage Interest Rates: An Empirical Analysis of the Euro Area Countries

Using the harmonised statistics of the Eurosystem, this paper focuses on the determinants of the fixed and variable mortgage interest rates applied to new transactions concluded by households resident in euro area countries in the period between 2003 and 2009. The econometric analyses show that of the various explanatory factors considered, the cost of deposits, the level of guarantees given, the intensity of the bank-customer relationship and the efficiency of the civil justice system appear to have the most influence on mortgage interest rates. Bank competitiveness does not appear to affect interest rates. There is no evidence that the financial crisis has generally led to the application of more stringent economic conditions to mortgages by the European banking industry. What does emerge is each country’s very different reaction to the crisis.

Survivability strategies in multihop wireless networks [Accepted From Open Call

Survivability is an important network characteristic that provides a certain level of data delivery guarantees. The degree of survivability is usually governed by the data transfer mechanism or protocol that delivers data from source to destination. In this article we survey and discuss a variety of survivability issues, challenges, and mechanisms in multihop wireless networks. Unlike some previous surveys, we do not focus only on multipath routing techniques. We try to cover a broader spectrum of survivability techniques in the literature. Moreover, we discuss new directions in survivability that use the network coding technique in order to achieve a better degree of scalability, which is usually an issue in most survivability techniques, especially in wireless networks.