Robust non‐fragile approach to resilient design of PID‐based blade pitch control for wind energy conversion system

The design of a blade pitch controller (BPC) for wind energy conversion system (WECS) applications is load‐dependent and has to be adjusted for each operating condition. Thus, BPC robustness is important for coping with the endless variations in operating conditions. The boundaries of a robust stability region are determined in regards to the controller parameters plane using their relevant set of polynomial inequalities via Referential Integrity between Routh‐Hurwitz criterion and Root‐Locus (RI‐RH/RL) approach. Constrained and unconstrained stability regions respectively are defined through a novel hybrid control technique based on the combination of both RI‐RH/RL and Kharitonov (Kh) theorem. The hybrid RI‐Kh method is used for globally analyzing all vertex plants to ensure the proposed controller robustness, non‐fragility, and resilience by selecting its parameters at the center of the robust stability region. The optimal BPC‐PID parameters estimated using different optimization techniques are always located within the specified stability region. Thus, the capability of the RI‐Kh approach in determining the most robust, non‐fragile and resilient controller is verified. Through simulation results, the effectiveness of the proposed approach and its applicability to WECS' global stabilization are validated.     

Design exemplars for synchronous e-learning: A design theory approach

Synchronous e-learning has received much less research attention, as compared with asynchronous e-learning. Practitioners that consider using and designing synchronous e-learning are in urgent need of guidance. In order to address this need, we propose design exemplars for synchronous e-learning. They are directed towards a primary constituent community of teachers, administrators, managers and developers of e-learning. The exemplars have been theoretically as well as empirically grounded through cross-case analyses of studies conducted between 2003 and 2006. Moreover, the exemplars have been evaluated by conducting focus group sessions with experienced practitioners having experience of using and developing e-learning. Strong support was identified for each design exemplar. The exemplars can be used as research hypotheses and be tested in future design research.     

A simulator-based approach to cellular manufacturing system design

Cellular Manufacturing (CM) is a product-oriented organizational strategy that is recognized as one of the critical elements in the rejuvenation of outdated and unproductive manufacturing plants. Successful planning, design, and implementation of Cellular Manufacturing Systems (CMS) require the development of sound, replicable system design approaches. In this paper, a simulator-based approach for the design of manufacturing cells and systems is described. The approach utilizes holistic systems design concepts and addresses Hitomi's three fundamental aspects of manufacturing systems: transformational, procedural, and structural. A distinction is made between system logic and system structure and the concepts of logical design and physical design are utilized. The approach described can assist the designer by providing a systematic holistic methodology to the CMS design process.     

A function-centred approach to joint driver-vehicle system design

Throughout the history human–machine systems design has had a technological bias in the sense that design for technology came first and design for humans as a distant second. Over the years this situation became untenable because the growing system complexity made a decomposition approach to design inadequate. Seeing that technology-centered design had failed, the pendulum swung to the other side taking the human as the center of things. Yet human-centered design is just as inadequate as machine-centered design, since it implies a dichotomy where one part of the system is seen as opposed to the other. This applies not least to the case of automotive environments, where the interaction has a clear purpose, namely safely to negotiate the traffic. Design should therefore embrace a function-centered view where the focus is the joint driver-vehicle system. Design should serve to further the purposes or goals of the joint system, i.e., to be in control vis-à-vis the dynamic traffic environment, by taking the relative strengths and limitations of the components into account and by describing the system on multiple levels.     

A two-phase analytic approach to robotic system design

A two-phase analytic approach to robotic system design is presented. The first phase evaluates the robotic technological classes according to their functional adequacy; the next phase specifies the desired robotic configuration. The methodology developed here is demonstrated for the case of installing a robot in an automated investment casting shelling production line.     

混合设计方法

在系统设计师和管理者中间,有一场旷日持久的争论,就是到底是应该采用由上至下的设计技术还是采用由下至上的技术。经验证明,两种方法混合的效果最佳。     

Emotion recognition from speech using sub-syllabic and pitch synchronous spectral features

In this work, spectral features extracted from sub-syllabic regions and pitch synchronous analysis are proposed for speech emotion recognition. Linear prediction cepstral coefficients, mel frequency cepstral coefficients and the features extracted from high amplitude regions of spectrum are used to represent emotion specific spectral information. These features are extracted from consonant, vowel and transition regions of each syllable to study the contribution of these regions toward recognition of emotions. Consonant, vowel and the transition regions are determined using vowel onset points. Spectral features extracted from each pitch cycle, are also used to recognize emotions present in speech. The emotions used in this study are: anger, fear, happy, neutral and sad. The emotion recognition performance using sub-syllabic speech segments are compared with the results of conventional block processing approach, where entire speech signal is processed frame by frame. The proposed emotion specific features are evaluated using simulated emotion speech corpus, IITKGP-SESC (Indian Institute of Technology, KharaGPur-Simulated Emotion Speech Corpus). The emotion recognition results obtained using IITKGP-SESC are compared with the results of Berlin emotion speech corpus. Emotion recognition systems are developed using Gaussian mixture models and auto-associative neural networks. The purpose of this study is to explore sub-syllabic regions to identify the emotions embedded in a speech signal, and if possible, to avoid processing of entire speech signal for emotion recognition without serious compromise in the performance.     

A novel approach to design classifiers using genetic programming

We propose a new approach for designing classifiers for a c-class (c/spl ges/2) problem using genetic programming (GP). The proposed approach takes an integrated view of all classes when the GP evolves. A multitree representation of chromosomes is used. In this context, we propose a modified crossover operation and a new mutation operation that reduces the destructive nature of conventional genetic operations. We use a new concept of unfitness of a tree to select trees for genetic operations. This gives more opportunity to unfit trees to become fit. A new concept of OR-ing chromosomes in the terminal population is introduced, which enables us to get a classifier with better performance. Finally, a weight-based scheme and some heuristic rules characterizing typical ambiguous situations are used for conflict resolution. The classifier is capable of saying "don't know" when faced with unfamiliar examples. The effectiveness of our scheme is demonstrated on several real data sets.     

A moving horizon approach to Networked Control system design

This paper presents a control system design strategy for multivariable plants where the controller, sensors and actuators are connected via a digital, data-rate limited, communications channel. In order to minimize bandwidth utilization, a communication constraint is imposed which restricts all transmitted data to belong to a finite set and only permits one plant to be addressed at a time. We emphasize implementation issues and employ moving horizon techniques to deal with both control and measurement quantization issues. We illustrate the methodology by simulations and a laboratory-based pilot-scale study.     

A feature-based approach to injection mould cooling system design

Most existing work on the design of cooling systems of plastic injection moulds has been focused on the detailed analysis or the optimization of the cooling system. However, before a cooling system can be analysed or optimized, an initial design has to be developed. We explore a new design synthesis approach to solve this initial design problem. A plastic part with a complex shape is decomposed into simpler shape features. The cooling systems of the individual features are first obtained, they are then combined to form the cooling system of the entire part. Decomposing a complex shape into shape features is a feature recognition problem. A new algorithm for the recognition of features specific to cooling system design is developed. Design examples generated by the design synthesis process are analysed by C-Mold to verify the feasibility of the approach.     

A graph theoretic approach to multivariable control system design

A graph theoretic approach is described for the design of multivariable control for large systems as an alternative to geometric methods. An example is given f⊙r a distillation column to demonstrate the technique, with a particular reference to aspects of disturbance rejection and the possibilities for pole assignment.     

A prototype approach to information system design and development

Many organisations view the development of an information processing system as a linear process consisting of an ordered sequence of steps from conception to hand-over and make no provision for alternative strategies. While excellent in many circumstances, the linear strategy is not the only possible approach. This paper discusses alternatives, with particular reference to a prototype strategy, which has some important advantages.     

Nonparallel training for voice conversion based on a parameter adaptation approach

The objective of voice conversion algorithms is to modify the speech by a particular source speaker so that it sounds as if spoken by a different target speaker. Current conversion algorithms employ a training procedure, during which the same utterances spoken by both the source and target speakers are needed for deriving the desired conversion parameters. Such a (parallel) corpus, is often difficult or impossible to collect. Here, we propose an algorithm that relaxes this constraint, i.e., the training corpus does not necessarily contain the same utterances from both speakers. The proposed algorithm is based on speaker adaptation techniques, adapting the conversion parameters derived for a particular pair of speakers to a different pair, for which only a nonparallel corpus is available. We show that adaptation reduces the error obtained when simply applying the conversion parameters of one pair of speakers to another by a factor that can reach 30%. A speaker identification measure is also employed that more insightfully portrays the importance of adaptation, while listening tests confirm the success of our method. Both the objective and subjective tests employed, demonstrate that the proposed algorithm achieves comparable results with the ideal case when a parallel corpus is available.     

High quality voice conversion using prosodic and high-resolution spectral features

Voice conversion methods have advanced rapidly over the last decade. Studies have shown that speaker characteristics are captured by spectral feature as well as various prosodic features. Most existing conversion methods focus on the spectral feature as it directly represents the timbre characteristics, while some conversion methods have focused only on the prosodic feature represented by the fundamental frequency. In this paper, a comprehensive framework using deep neural networks to convert both timbre and prosodic features is proposed. The timbre feature is represented by a high-resolution spectral feature. The prosodic features include F0, intensity and duration. It is well known that DNN is useful as a tool to model high-dimensional features. In this work, we show that DNN initialized by our proposed autoencoder pretraining yields good quality DNN conversion models. This pretraining is tailor-made for voice conversion and leverages on autoencoder to capture the generic spectral shape of source speech. Additionally, our framework uses segmental DNN models to capture the evolution of the prosodic features over time. To reconstruct the converted speech, the spectral feature produced by the DNN model is combined with the three prosodic features produced by the DNN segmental models. Our experimental results show that the application of both prosodic and high-resolution spectral features leads to quality converted speech as measured by objective evaluation and subjective listening tests.     

An approach to assessing virtual environments for synchronous and remote collaborative design

This paper considers applying novel Virtual Environments (VEs) in collaborative product design, focusing on reviewing activities. Companies are usually anchored to commercial ICT tools, which are mature and reliable. However, two main problems emerge: the difficulty in selecting the most suitable tools for specific purposes and the complexity in evaluating the impact that using technology has on design collaboration. The present work aims to face both aspects by proposing a structured benchmarking method based on expert judgements and defining a set of benchmarking weights based on experimental tests. The method considers both human–human interaction and teamwork-related aspects. A subsequent evaluation protocol considering both process efficiency and human–human interaction allows a closed-loop verification process. Pilot projects evaluate different technologies, and the benchmarking weights are verified and adjusted for more reliable system assessment. This paper focuses on synchronous and remote design review activities: three different tools have been compared according to expert judgements. The two best performing tools have been implemented as pilot projects within real industrial chains. Design collaboration has been assessed by considering both process performance and human–human interaction quality, as well as benchmarking results validated by indicating some corrective actions. The final benchmarking weights can thus be further adopted for an agile system benchmark in synchronous and remote design. The main findings suggest defining both an innovative process to verify the expert benchmark reliability and a trusty benchmarking method to evaluate tools for synchronous and remote design without experimental testing. Furthermore, the proposed method has a general validity and can be properly set for different collaborative dimensions.     

A new approach to input device key design using fingerprints

A new approach to designing input device keys is proposed, and a TV remote controller is used as an example to demonstrate the new approach for studying the relationship between fingerprints and key geometry. One hundred subjects' fingerprints of thumbs and index fingers of both hands were collected, and a computer program was used for converting the fingerprint to a bitmap form. Subsequently, the data were analysed to provide some guidelines for determining the key size and key shape for the input device. Finally, the fingerprints were used to study the pattern of finger press and the justification for keycap curvature for finger placement. The results showed that the new approach can be useful in guiding designers of input device keys. A further benefit of this study is in providing a more systematic approach with considerable general potential for studying input device keys.