Sensitivity analysis approaches applied to systems biology models

With the rising application of systems biology, sensitivity analysis methods have been widely applied to study the biological systems, including metabolic networks, signalling pathways and genetic circuits. Sensitivity analysis can provide valuable insights about how robust the biological responses are with respect to the changes of biological parameters and which model inputs are the key factors that affect the model outputs. In addition, sensitivity analysis is valuable for guiding experimental analysis, model reduction and parameter estimation. Local and global sensitivity analysis approaches are the two types of sensitivity analysis that are commonly applied in systems biology. Local sensitivity analysis is a classic method that studies the impact of small perturbations on the model outputs. On the other hand, global sensitivity analysis approaches have been applied to understand how the model outputs are affected by large variations of the model input parameters. In this review, the author introduces the basic concepts of sensitivity analysis approaches applied to systems biology models. Moreover, the author discusses the advantages and disadvantages of different sensitivity analysis methods, how to choose a proper sensitivity analysis approach, the available sensitivity analysis tools for systems biology models and the caveats in the interpretation of sensitivity analysis results.     

All-optical code-division-multiplexing technique supporting multirate data communications and local-area-network interconnections

An efficient all-optical code-division-multiplexing (AOCDM) technique is proposed to support multirate data communications and local-area-network (LAN) interconnections with multiple protocols. To achieve this goal, we use a strict optical orthogonal code (OOC) in multirate AOCDM systems to guarantee that both cross- and autocorrelation constraints are minimum (i.e., 1) for incoherent optical processing. In contrast, the use of a conventional OOC may result in correlation constraints of 2, which in turn can degrade system performance. Moreover, implementation issues on AOCDM systems are discussed. These include the design of low-cost optical transmitters and the trade-off among coherence time, spectral width, and pulse width for AOCDM systems. It is shown that multirate AOCDM systems have a high operation flexibility to support data communications and LAN interconnections of both equal and multiple bit rates. For multirate data transmissions, the proposed system can have a better bandwidth efficiency and a lower bit error rate than a system that uses a conventional OOC.     

Biomimetic approaches toward smart bio-hybrid systems

Bio-integrated materials and devices can blur the interfaces between living and artificial systems. Microfluidics, bioelectronics, and engineered nanostructures, with close interactions with biology at the cellular or tissue levels, have already yielded a spectrum of new applications. Many new designs emerge, including of organ-on-a-chip systems, biodegradable implants, electroceutical devices, minimally invasive neuro-prosthetic tools, and soft robotics. In this review, we highlight a few recent advances of the fabrication and application of smart bio-hybrid systems, with a particular emphasis on the three-dimensional (3D) bio-integrated devices that mimic the 3D feature of tissue scaffolds. Moreover,neurons integrated with engineered nanostructures for wireless neuromodulation and dynamic neural output are briefly discussed. We also discuss the progress in the construction of cell-enabled soft robotics, where a tight coupling of the synthetic and biological parts is crucial for efficient function. Finally, we summarize the approaches for enhancing bio-integration with biomimetic micro- and nanostructures.

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Contrasting approaches to the generation of environmental improvement options for production systems

This article reviews two common types of improvement tools presently used in industry to identify opportunities to prevent or at least to reduce the environmental impacts of production systems and processes. Despite their proven ability to result in appropriate environmental improvement options in different industry sectors, their successful application is hampered by the fact that these tools do not take the specific causes of the environmental impacts of the production process into account, i.e. the question of which process features cause the environmental impacts of the production process is not raised nor is the flexibility for change of the production system taken into consideration. This paper sets the stage for a new generation of improvement tools, based on an environmental diagnosis of the production system. The diagnosis aims to result in a thorough understanding of the production system to guide and drive the identification of environmental improvement options that specifically target process-, product-, and site-specific environmental conditions. Alternative ways to develop such a diagnostic approach on the basis of presently used tools are being explored, and a synthesis thereof is proposed to achieve synergy between these contrasting approaches. Received: 7 August 2000 / Accepted: 8 November 2000     

Energy-saving operation approaches for urban rail transit systems

With the accelerated urbanization in China, passenger demand has dramatically increased in large cities, and traffic congestion has become serious in recent years. Developing public urban rail transit systems is an indispensable approach to overcome these problems. However, the high energy consumption of daily operations is an emerging issue due to increased rail transit networks and passenger demands. Thus, reducing the energy consumption and operational cost by using advanced optimization methodologies is an urgent task for operation managers. This work systematically introduces energy-saving approaches for urban rail transit systems in three aspects, namely, train speed profile optimization, utilization of regenerative energy, and integrated optimization of train timetable and speed profile. Future research directions in this field are also proposed to meet increasing passenger demands and network-based urban rail transit systems.     

Design strategies to simplify and miniaturize imaging systems

We present the range of optical architectures for imaging systems based on a single optical component, an aperture stop, and a detector. Thanks to the formalism of third-order Seidel aberrations, several strategies of simplification and miniaturization of optical systems are examined. Figures of merit are also introduced to assess the basic optical properties and performance capabilities of such systems; by this way, we show the necessary trade-off between simplicity, miniaturization, and optical performance.     

Sequencing approaches for multiple-aisle automated storage and retrieval systems

Automated storage and retrieval systems (AS/RS) are used in high velocity distribution centres to provide accurate and fast order processing. While almost every industrial system is comprised of many aisles, most of the academic research on the operational aspects of AS/RS is devoted to single-aisle systems, probably due to the broadly accepted hypothesis proposing that an m aisles system can be modelled as m 1-aisle independent systems. In this article, we present two multi-aisles sequencing approaches and evaluate their performance when all the aisles are managed independently first, and then in a global manner. Computational experiments conducted on a multi-aisle AS/RS simulation model clearly demonstrate that a multi-aisle system cannot be accurately represented by multiple single-aisle systems. The numerical results demonstrate that, when dealing with random storage, globally sequencing multi-aisle AS/RS leads to makespan reductions ranging from 14 to 29% for 2- and 3-aisle systems, respectively.     

Heuristic and analytic approaches to the introduction of integral qualitative indexes in large industrial systems

Heuristic and analytical approaches to the introduction of integral qualitative indexes in large industrial systems as functions of partial indexes characterizing various aspects of quality are examined.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 6–8, October, 1994.     

Comparison and unification of non-Hermitian and Lindblad approaches with applications to open quantum optical systems

We compare two approaches to open quantum systems, namely, the non-Hermitian dynamics and the Lindblad master equation. In order to deal with more general dissipative phenomena, we propose the unified master equation that combines the characteristics of both of these approaches. This allows us to assess the differences between them as well as to clarify which observed features come from the Lindblad or the non-Hermitian part, when it comes to experiment. Using a generic two-mode single-atom laser system as a practical example, we analytically solve the dynamics of the normalized density matrix operator. We study the two-level model in a number of cases (depending on parameters and types of dynamics), compute different observables and study their physical properties. It turns out that one can not only able to describe the different types of damping in dissipative quantum optical systems but also mimic the undamped anharmonic oscillatory phenomena which happen in quantum systems with more than two levels (while staying within the framework of the analytically simple two-mode approximation).     

Heuristic unidirectional flowpath design approaches for automated guided vehicle systems

In this paper, we address the flowpath design issue of automated guided vehicle systems (AGVSs). In particular we concentrate on the design of unidirectional flowpaths (i.e. vehicles are restricted to travel only in one direction along a given segment of the flowpath). We have developed five different heuristics for the design of unidirectional AGVSs. We have also developed simulated annealing algorithms for the above problem. Our extensive computational results indicate that a composite heuristic (i.e. one that combines the most successful of our five heuristics) yields solutions of comparable quality in a fraction of the time required by simulated annealing. For large-size flowpath design problems, we advocate the usage of composite heuristics over simulated annealing, and in particular for the cases in which inaccurate estimates for the input data in our design problem exist     

General approaches to accounting for energy dissipation in the material during transverse vibrations of elastic systems

Approximate methods of nonlinear mechanics are used to develop a method of accounting for energy dissipation in a material undergoing cyclic deformation while in a nonuniform stress state during transverse vibration.Translated from Problemy Prochnosti, Nos. 5–6, pp. 79–86, May–June, 1995.     

Design approaches for the X band LLRF system

The low-level RF (LLRF) system regulates disturbances over a limited bandwidth in accordance with its capabilities and the RF loop parameters. The disturbances usually originate in the RF system or can be coupled to the RF system from the environment. In this paper a general overview of the possible design approaches for a digital LLRF system operating in X band is presented. Firstly, the possible design approaches of the RF front/back ends are presented and reviewed. We also define the main design parameters for the RF front/back ends. Parameters like isolation between channels, noise, gain, linearity and number of IF stages are put into the perspective of machines using RF components in the X band. An important part of the LLRF system is the local RF timing generation and distribution, which is also treated in the paper. In the second part of the paper the main design approaches in the digital signal processing part of the LLRF system are presented. The emphasis is on the algorithms that are machine specific. Some standard processing algorithms like adaptive feed-forward and arbitrary shaping of feed-forward pulses are presented. Finally, a suggestion for the X band LLRF design is given.     

Intelligent process-aware information systems to support agility in disaster relief operations: a survey of emerging approaches

Agility is a key characteristic in disaster relief operations. Intelligent process-aware information systems (IPAISs) can support agility in disaster relief operations through providing information and process reach and richness to manage dynamic inter-operations. In this research, based on relevant reference architectures, a conceptual overview of an IPAIS to support agility in disaster relief operations is described. This conceptual overview includes the dynamic partnering, the collaborative process composition, the collaborative ontology management, the global workflow engine, the run-time coordination, the dynamic rule management, the run-time process proposer, and the dynamic interoperability adaptor components. Based on this conceptual overview, a systematic literature review is conducted to explore emerging approaches that can be applied to realise intelligent process-centred collaborative inter-operations to respond disasters. The findings of the conducted review show the applicability of the emerging multi-agent service-oriented modelling and analysis approaches, optimal control theory based methodologies, social network analysis techniques, data-driven inductive methods, resilient-centred approaches for robustness and agility, self-organisation mechanisms based on cyber physical systems and systems of systems perspectives, simulation methods, and trust management procedures to support the realisation of the components of an IPAIS in the context of disaster relief operations.     

Performance evaluation of dynamic scheduling approaches in vehicle-based internal transport systems

This paper studies the performance of static and dynamic scheduling approaches in vehicle-based internal transport (VBIT) systems and is one of the first to systematically investigate under which circumstances, which scheduling method helps in improving performance. In practice, usually myopic dispatching heuristics are used, often using look-ahead information. We argue more advanced scheduling methods can help, depending on circumstances. We introduce three basic scheduling approaches (insertion, combined and column generation) for the static problem. We then extend these to a dynamic, real-time setting with rolling horizons. We propose two further real-time scheduling approaches: dynamic assignment with and without look-ahead. The performances of the above five scheduling approaches are compared with two of the best performing look-ahead dispatching rules known from the literature. The performance of the various approaches depends on the facility layout and work distribution. However, column generation, the combined heuristic, and the assignment approach with look-ahead consistently outperform dispatching rules. Column generation can require substantial calculation time but delivers very good performance if sufficient look-ahead information is available. For large scale systems, the combined heuristic and the dynamic assignment approach with look ahead are recommended and have acceptable calculation times.