Robustness Tradeoffs Research Articles

Imperceptibility—Robustness tradeoff studies for ECG steganography using Continuous Ant Colony Optimization

ECG Steganography ensures protection of patient data when ECG signals embedded with patient data are transmitted over the internet. Steganography algorithms strive to recover the embedded patient data entirely and to minimize the deterioration in the cover signal caused by the embedding. This paper presents a Continuous Ant Colony Optimization (CACO) based ECG Steganography scheme using Discrete Wavelet Transform and Singular Value Decomposition. Quantization techniques allow embedding the patient data into the ECG signal. The scaling factor in the quantization techniques governs the tradeoff between imperceptibility and robustness. The novelty of the proposed approach is to use CACO in ECG Steganography, to identify Multiple Scaling Factors (MSFs) that will provide a better tradeoff compared to uniform Single Scaling Factor (SSF). The optimal MSFs significantly improve the performance of ECG steganography which is measured by metrics such as Peak Signal to Noise Ratio, Percentage Residual Difference, Kullback–Leibler distance and Bit Error Rate. Performance of the proposed approach is demonstrated on the MIT-BIH database and the results validate that the tradeoff curve obtained through MSFs is better than the tradeoff curve obtained for any SSF. The results also advocate appropriate SSFs for target imperceptibility or robustness.

Digital watermarking algorithm based on scale-invariant feature regions in non-subsampled contourlet transform domain

Contraposing the need of the robust digital watermark for the copyright protection field, a new digital watermarking algorithm in the non-subsampled contourlet transform(NSCT) domain is proposed. The largest energy sub-band after NSCT is selected to embed watermark. The watermark is embedded into scaleinvariant feature transform(SIFT) regions. During embedding, the initial region is divided into some cirque sub-regions with the same area, and each watermark bit is embedded into one sub-region.Extensive simulation results and comparisons show that the algorithm gets a good trade-off of invisibility, robustness and capacity,thus obtaining good quality of the image while being able to effectively resist common image processing, and geometric and combo attacks, and normalized similarity is almost all reached.

Performance and Strategy: Simultaneous Equations Analysis of Long-lived Firms

A simultaneous equations model of performance, strategy and size is tested using fieldwork evidence on long-lived firms in Scotland. Estimation is by I3SLS, with correction for sample selection bias. The contributions of this paper are that it: (a) grounds estimation on fieldwork evidence; (b) calibrates performance and competitive strategy; (c) tests and models endogeneity; and (d) computes robust trade-off elasticities between firm size and performance. It shows how this trade-off provides the entrepreneur with two strong incentives: (i) to seek greater efficiency typically by an increase in the human capital of the ‘core’ workforce; (ii) to achieve higher levels of performance by adopting more diverse competitive strategies.

The Level of Residual Dispersion Variation and the Power of Differential Expression Tests for RNA-Seq Data

RNA-Sequencing (RNA-Seq) has been widely adopted for quantifying gene expression changes in comparative transcriptome analysis. For detecting differentially expressed genes, a variety of statistical methods based on the negative binomial (NB) distribution have been proposed. These methods differ in the ways they handle the NB nuisance parameters (i.e., the dispersion parameters associated with each gene) to save power, such as by using a dispersion model to exploit an apparent relationship between the dispersion parameter and the NB mean. Presumably, dispersion models with fewer parameters will result in greater power if the models are correct, but will produce misleading conclusions if not. This paper investigates this power and robustness trade-off by assessing rates of identifying true differential expression using the various methods under realistic assumptions about NB dispersion parameters. Our results indicate that the relative performances of the different methods are closely related to the level of dispersion variation unexplained by the dispersion model. We propose a simple statistic to quantify the level of residual dispersion variation from a fitted dispersion model and show that the magnitude of this statistic gives hints about whether and how much we can gain statistical power by a dispersion-modeling approach.

Beyond optimality: Multistakeholder robustness tradeoffs for regional water portfolio planning under deep uncertainty

AbstractWhile optimality is a foundational mathematical concept in water resources planning and management, “optimal” solutions may be vulnerable to failure if deeply uncertain future conditions deviate from those assumed during optimization. These vulnerabilities may produce severely asymmetric impacts across a region, making it vital to evaluate the robustness of management strategies as well as their impacts for regional stakeholders. In this study, we contribute a multistakeholder many‐objective robust decision making (MORDM) framework that blends many‐objective search and uncertainty analysis tools to discover key tradeoffs between water supply alternatives and their robustness to deep uncertainties (e.g., population pressures, climate change, and financial risks). The proposed framework is demonstrated for four interconnected water utilities representing major stakeholders in the “Research Triangle” region of North Carolina, U.S. The utilities supply well over one million customers and have the ability to collectively manage drought via transfer agreements and shared infrastructure. We show that water portfolios for this region that compose optimal tradeoffs (i.e., Pareto‐approximate solutions) under expected future conditions may suffer significantly degraded performance with only modest changes in deeply uncertain hydrologic and economic factors. We then use the Patient Rule Induction Method (PRIM) to identify which uncertain factors drive the individual and collective vulnerabilities for the four cooperating utilities. Our framework identifies key stakeholder dependencies and robustness tradeoffs associated with cooperative regional planning, which are critical to understanding the tensions between individual versus regional water supply goals. Cooperative demand management was found to be the key factor controlling the robustness of regional water supply planning, dominating other hydroclimatic and economic uncertainties through the 2025 planning horizon. Results suggest that a modest reduction in the projected rate of demand growth (from approximately 3% per year to 2.4%) will substantially improve the utilities' robustness to future uncertainty and reduce the potential for regional tensions. The proposed multistakeholder MORDM framework offers critical insights into the risks and challenges posed by rising water demands and hydrological uncertainties, providing a planning template for regions now forced to confront rapidly evolving water scarcity risks.

Decentralized predictive thermal control for buildings

This paper studies the problem of decentralized control design for thermal control in buildings, to achieve a satisfactory trade-off between underlying performance and robustness objectives. An output-feedback, model predictive framework is used for decentralized control which is based on a reduced order system representation. It entails the use of decentralized extended state observers to address the issue of unavailability of all states and disturbances. The decision on control architecture selection is based on an agglomerative clustering methodology developed previously [22]. The potential use of the proposed control design methodology is demonstrated in simulation on a multi-zone building, which quantifies the tradeoffs in performance and robustness with respect to the degree of decentralization.

Performance and robustness trade-offs in PID control

Control design is a rich problem which requires consideration of many issues such as load disturbance attenuation, set-point tracking, robustness with respect to process variations and model uncertainty, and effects of measurement noise. The purpose of this paper is to provide insight into the trade-offs between performance and robustness explicitly. This is accomplished by introducing plots that show the trade-offs for PI and PID control. These also provide valuable understanding of design compromises used for common PI design methods.

Reliability of a stretchable interconnect utilizing terminated, in-plane meandered copper conductor

The pursuit for reliable, deformable electronic systems took two major paths, utilizing either conductive elastomers or metal conductors. In the case of the latter, a mechanical robustness trade-off is made in return for metallic conductor native low resistivity allowing for realization of power demanding and large area applications as well (e.g. conformable lighting and signage). The mechanical trade-off stems from the metal conductor intrinsic inability for significant elongation without failure. One of many present attempts at enabling a metal conductor to perform in an elastomeric medium without failure is the SMI (Stretchable Molded Interconnect), a PCB compatible technology developed at the CMST. Its concept relies on an in-plane, meandered, metal track embedded into a soft, elastomeric material. This work focuses at cyclic, uniaxial elongation endurance and reliability assessment (Weibull analysis) of such interconnect in its most simple form - utilizing unsupported, meandered copper tracks embedded in PDMS (Polydimethylsiloxane). The tracks are evaluated as short interconnects (a few meander wavelengths long) terminating between flexible (non-stretchable) regions to incorporate the effect of flex-stretch transition mechanics on reliability. This is an important assessment for optimizing the interconnect geometry for practical applications where flex-stretch transitions will be inevitable, and reliability under repeated deformation is of interest (e.g. stretchable circuits for integration in textile). An attempt is made to reinforce the meander geometry by tapering the transitions, but a negative impact on reliability is observed. It is clearly demonstrated that the wearout of the interconnect is strongly related to the amount of copper present in the interconnect.

Synthetic Sequence Design for Signal Location Search

We present a new approach to identify the locations of critical DNA or RNA sequence signals which couples large-scale synthesis with sophisticated designs employing combinatorial group testing and balanced Gray codes. Experiments in polio and adenovirus demonstrate the efficiency and generality of this procedure. In this paper, we give a new class of consecutive positive group testing designs, which offer a better tradeoff of cost, resolution, and robustness than previous designs for signal search.

Secure hybrid multibit multiplicative watermarking for media distribution over mobile Internet

AbstractWith the rapid development and rich applications of mobile Internet, security issues become urgent. For example, piracy of media content (image, audio, or video) becomes easier because mobile Internet provides more ways to re‐distribute media contents. Watermarking has been regarded as a potential solution for identifying pirate copies. However, the watermarking algorithms' security and robustness are still not ideal enough for practical applications, especially in mobile scenarios with more attacks. In this paper, a novel hybrid multiplicative watermarking algorithm is proposed to obtain higher security and good robustness. In this algorithm, two embedding rules are changed according to the secret key, which embed the watermark into Discrete Wavelet Transform (DWT) coefficients. The secret key improves the watermark system's security. Additionally, the optimum and locally optimum hybrid multiplicative watermarking decoders are proposed, respectively, to detect the watermark. Because it works with two rules, it obtains a tradeoff in robustness. Various comparative experiments are carried out, and results are given to prove the valid of theoretical analysis. Copyright © 2013 John Wiley & Sons, Ltd.

Architecture and robustness tradeoffs in speed-scaled queues with application to energy management

We consider single-pass, lossless, queueing systems at steady-state subject to Poisson job arrivals at an unknown rate. Service rates are allowed to depend on the number of jobs in the system, up to a fixed maximum, and power consumption is an increasing function of speed. The goal is to control the state dependent service rates such that both energy consumption and delay are kept low. We consider a linear combination of the mean job delay and energy consumption as the performance measure. We examine both the ‘architecture’ of the system, which we define as a specification of the number of speeds that the system can choose from, and the ‘design’ of the system, which we define as the actual speeds available. Previous work has illustrated that when the arrival rate is precisely known, there is little benefit in introducing complex (multi-speed) architectures, yet in view of parameter uncertainty, allowing a variable number of speeds improves robustness. We quantify the tradeoffs of architecture specification with respect to robustness, analysing both global robustness and a newly defined measure which we call local robustness.

Capacity and Robustness Tradeoffs in Bloom Filters for Distributed Applications

The Bloom filter is a space-efficient data structure often employed in distributed applications to save bandwidth during data exchange. These savings, however, come at the cost of errors in the shared data, which are usually assumed low enough to not disrupt the application. We argue that this assumption does not hold in a more hostile environment, such as the Internet, where attackers can send a carefully crafted Bloom filter in order to break the application. In this paper, we propose the concatenated Bloom filter (CBF), a robust Bloom filter that prevents the attacker from interfering on the shared information, protecting the application data while still providing space efficiency. Instead of using a single large filter, the CBF concatenates small subfilters to improve both the filter robustness and capacity. We propose three CBF variants and provide analytical results that show the efficacy of the CBF for different scenarios. We also evaluate the performance of our filter in an IP traceback application and simulation results confirm the effectiveness of the proposed mechanism in the face of attackers.

Performance, Metastability, and Soft-Error Robustness Trade-offs for Flip-Flops in 40 nm CMOS

In modern CMOS processes, soft errors and metastability are two prominent failure mechanisms. Radiation induced single event upsets, or soft-errors, have become a dominant failure mechanism in sub-100 nm CMOS memory and logic circuits. The effects of metastability have also becoming increasingly significant in high-speed applications implemented in nanometric processes. In this paper the design trade-offs for flip-flops between performance, soft-error robustness and metastability are described. Soft-error robust flip-flops are implemented based on both the DICE cell and the Quatro cell. SPICE simulations are used to characterize the transient performance and metastability robustness, and device level simulations were performed to quantify the soft-error robustness. The flip-flops were fabricated in the TSMC 40 nm process and radiation measurements were performed at several test facilities. The Quatro flip-flop showed improved soft-error robustness and metastability when compared with a reference D flip-flop and a DICE flip-flop.

A requirement for the mutation operator in continuous optimization

During the recent decades, much effort has been dedicated to revise and improve the evolution operators of evolutionary algorithms. This article aims at minimums of an efficient mutation operator in continuous problems for which reachability, scalability, unbiasedness and isotropy have already been considered necessary. A new requirement, called robust exploration and exploitation trade-off, is introduced which is usually satisfied for common univariate density functions in 1D space, while for higher dimensions, these density functions should be revised, otherwise the exploration or exploitation abilities of sampling turns highly limited. Empirical simulation is carried out to check the validity of the drawn conclusions, which verifies that if modification of the density function is ignored, dramatic performance deterioration can be concluded.

Transparency and trade-offs in water planning

summary The building of robust and transparent trade-offs needs to be supported by a sound understanding of the water planning process, baseline conditions, and the range of interests and values that might be affected. To this end, several tools were tested for identifying interests and values and assessing how they might be impacted by change. These included a social impact study in South Australia and irrigator and stakeholder surveys in the Condamine, Queensland. A participatory approach to multiple criteria analysis was also trialled to assist understanding of preferences and values in water allocation trade-off deliberations. Evaluations of the use of these tools demonstrate their functionality in eliciting stakeholder values and expectations and help in bringing transparency to the logic behind the water planning decision-making process.

Unemployment and Income Inequality: A Puzzling Finding from the US in 1941-2010

Persisting high unemployment and income inequality are two serious problems in global macroeconomic management. This paper sets out to explore the possible connection behind the co-existence of the two problems with an empirical study of the US from 1941-2010. Using the wage share in aggregate personal income as a measurement of income inequality, it discovers a puzzle that is against common sense and conventional belief: there is a robust tradeoff relationship between the change rates of unemployment rate and the wage share throughout 1941-2010. It means that unemployment and income inequality are positively correlated. By making the distinction between the wage income from the primary distribution and employees’ welfare incomes from government transfer payments, it also finds that employees’ social welfare had a weak positive relationship with unemployment.

A Topology Control Algorithm of 3D Wireless Sensor Networks Based on Energy Consumption and Robustness Trade-off

A Topology Control Algorithm of 3D Wireless Sensor Networks Based on Energy Consumption and Robustness Trade-off

Robust fault detection for nonlinear networked systems with stochastic interval delay characteristics

In this paper, the problem of observer-based robust fault detection (RFD) for nonlinear networked systems with stochastic interval delay is investigated. By employing the information of probabilistic distribution of networked-induced time-varying delay, the observer-based fault detection filter as residual generator and a proposed performance index as objective function, the RFD of nonlinear networked systems is formulated as an optimization problem. The desired fault detection filter is constructed in terms of certain linear matrix inequalities, which depend on not only delay-interval but also delay-interval-occurrence-rate. Especially, the sub-optimal trade-off of strong robustness from residual signal to disturbance and parameter uncertainty, as well as high sensitivity to fault is obtained by a repeated application of a two-objective optimization algorithm. Numerical simulations are given to illustrate the effectiveness of proposed techniques.

Effective adaptive virtual queue: a stabilising active queue management algorithm for improving responsiveness and robustness

Adaptive virtual queue (AVQ) algorithm is an effective method aiming to achieve low loss, low delay and high-link utilisation at the link. However, it is difficult to guarantee fast response, strong robustness and good trade-off over a wide range of network dynamics. The authors propose a stabilising active queue management (AQM) algorithm – effective-AVQ, as an extension of AVQ, to improve the responsiveness and robustness of the transmission control protocol (TCP)/AQM system. Specifically, a proportional integral derivative (PID) neuron is introduced to tune the virtual link capacity dynamically. Also we derive the parameter self-tuning mechanism for the PID neuron from the Hebbian learning rule and gradient descent approach. The stability condition of the closed-loop system is presented based on the time-delay control theory. The performance of effective-AVQ is validated in the NS2 platform. Simulation results demonstrate that effective-AVQ outperforms AVQ in terms of steady-state and transient performance. It achieves fast response, expected link utilisation, low queue size and small delay jitter, being robust against dynamic network changes.

Reliable information embedding for image/video in the presence of lossy compression

Lossy compression is inherently contradictory with information hiding and may result in unreliable retrieval of embedded message. For most of the existing data hiding algorithms, the process of dealing with the conflict and trade-off of invisibility, capacity and robustness is done in an experimental fashion. We have developed an image and video unified data-embedding technique. The algorithm is capable of accurately retrieving hidden data after the embedded signals are subjected to JPEG/MPEG compression as long as its compression degree is above the predefined one. Embedding strategy is to integrate data hiding into the JPEG/MPEG coding structures and to combine the adjustment factor of the strength and quantity of data hiding with the control parameter of lossy compression, according to the constraint of human visual system, the demand of hiding capacity and distortion impact of lossy compression. Experimental evaluation demonstrates that the proposed algorithm allows us to hide data invisibly in an accurate retrievable way with effective and flexible trade-off mechanism in the presence of lossy compression. In addition, the scheme is robust to some common attacks including low-pass filtering, noisy interference, frame dropping and transcoding.