High-Performance GaN-Based Vertical-Injection Light-Emitting Diodes With TiO2–SiO 2 Omnidirectional Reflector and n-GaN Roughness

We have designed and fabricated a new type of GaN-based thin-film vertical-injection light-emitting diode (LED) with TiO₂-SiO ₂ omnidirectional reflector (ODR) and n-GaN roughness. The associated ODR designed for LED operation wavelength at 455 nm was integrated with patterned conducting channels for the purpose of vertical current spreading. With the help of laser lift-off and photo-electrochemical etching technologies, at a driving current of 350 mA and with chip size of 1 mm times 1 mm, the light-output power and the external quantum efficiency of our thin-film LED with TiO₂-SiO₂ ODR reached 330 mW and 26.7%. The result demonstrated 18% power enhancement when compared with the results from the thin-film LED with Al reflector replace     

An Optimal Parallel Co-Connectivity Algorithm

In this paper we consider the problem of computing the connected components of the complement of a given graph. We describe a simple sequential algorithm for this problem, which works on the input graph and not on its complement, and which for a graph on n vertices and m edges runs in optimal O(n+m) time. Moreover, unlike previous linear co-connectivity algorithms, this algorithm admits efficient parallelization, leading to an optimal O(log n)-time and O((n+m)log n)-processor algorithm on the EREW PRAM model of computation. It is worth noting that, for the related problem of computing the connected components of a graph, no optimal deterministic parallel algorithm is currently available. The co-connectivity algorithms find applications in a number of problems. In fact, we also include a parallel recognition algorithm for weakly triangulated graphs, which takes advantage of the parallel co-connectivity algorithm and achieves an O(log² n) time complexity using O((n+m²) log n) processors on the EREW PRAM model of computation.     

An intelligent service-based network architecture for wearable robots

We are developing a novel robot concept called the wearable robot. Wearable robots are mobile information devices capable of supporting remote communication and intelligent interaction between networked entities. In this paper, we explore the possible functions of such a robotic network and will present a distributed network architecture based on service components. In order to support the interaction and communication between the components in the wearable robot system, we have developed an intelligent network architecture. This service-based architecture involves three major mechanisms. The first mechanism involves the use of a task coordinator service such that the execution of the services can be managed using a priority queue. The second mechanism enables the system to automatically push the required service proxy to the client intelligently based on certain system-related conditions. In the third mechanism, we allow the system to automatically deliver services based on contextual information. Using a fuzzy-logic-based decision making system, the matching service can determine whether the service should be automatically delivered utilizing the information provided by the service, client, lookup service, and context sensors. An application scenario has been implemented to demonstrate the feasibility of this distributed service-based robot architecture. The architecture is implemented as extensions to the Jini network model.     

Workflow View Driven Cross-Organizational Interoperability in a Web Service Environment

Workflow technology has recently been employed not only within businesses but also as a framework for implementing e-services over the Internet. Such e-services typically require collaborative enactment of workflows across multiple organizations. In this paper, we propose the use of workflow views as a fundamental support mechanism for the interoperability of multiple workflows across business organizations. We present a meta-model of workflow views and their semantics using a cross-organization workflow example based on a supply-chain e-service. We also formulate an interoperation model of workflow views and its consistency criteria. Finally, this paper presents an implementation of the model based on XML and contemporary Web services technologies, with adaptation to our E-ADOME workflow engine.     

Robust eigenstructure assignment with minimum subspace separation

A computation method for delivering a state feedback controller that assigns closed‐loop eigenstructure with a minimum subspace separation and is robust towards unstructured perturbations is presented. The subspace separation is measured via the difference between two subspace projections, while the eigenstructure robustness is achieved by maximizing an upper bound on the allowable perturbation size such that the closed‐loop system remains stable. By exploiting the Sylvester equation parametrization, the constraint of pole assignment can be satisfied intrinsically and the robust eigenstructure assignment design essentially becomes an unconstrained optimization task. Analytical gradient formulas of the objective functions to be handled are developed. The design approach is demonstrated through numerical examples. Copyright © 2004 John Wiley & Sons, Ltd.     

Research on Ground Movement Laws for Strip Mining Under Thick Alluvium

With the discrete element method, the simulation and analysis of a series of numerical models were made. This research revealed ground movement laws for strip mining under thick alluvium and gave calculation formulae for the maximum ground subsidence and horizontal movement as a function of basement rock thickness and mining width, thus providing sound evidence for future strip mining under thick alluvium.     

Context-Independent Multilingual Emotion Recognition from Speech Signals

This paper presents and discusses an analysis of multilingual emotion recognition from speech with database-specific emotional features. Recognition was performed on English, Slovenian, Spanish, and French InterFace emotional speech databases. The InterFace databases included several neutral speaking styles and six emotions: disgust, surprise, joy, fear, anger and sadness. Speech features for emotion recognition were determined in two steps. In the first step, low-level features were defined and in the second high-level features were calculated from low-level features. Low-level features are composed from pitch, derivative of pitch, energy, derivative of energy, and duration of speech segments. High-level features are statistical presentations of low-level features. Database-specific emotional features were selected from high-level features that contain the most information about emotions in speech. Speaker-dependent and monolingual emotion recognisers were defined, as well as multilingual recognisers. Emotion recognition was performed using artificial neural networks. The achieved recognition accuracy was highest for speaker-dependent emotion recognition, smaller for monolingual emotion recognition and smallest for multilingual recognition. The database-specific emotional features are most convenient for use in multilingual emotion recognition. Among speaker-dependent, monolingual, and multilingual emotion recognition, the difference between emotion recognition with all high-level features and emotion recognition with database-specific emotional features is smallest for multilingual emotion recognition—3.84%.     

Modeling peirce-smith converter operating costs

A cost model for the operation of copper converters is developed in this study, allowing an evaluation of the economic impact of changes to operating procedures and/or injection technologies. The model uses material and enthalpybalances for the slag and copper blows in a Peirce-Smith converter. The length of the converting cycle is calculated from the capacity of the blowers and the required blast along with the times required for other operations such as charging and skimming and idle time. Downtime, labor, and materials for converter lining repair as well as other costs such as oxygen enrichment are also considered in the cost calculations. The model is formulated in a spreadsheet using common programming language and is easily extended to examine the costs of alternative operating strategies or injection technologies such as high-pressure, shrouded injection. Example calculations showing the cost benefits of changing operating procedures and technology are presented.     

Microwave imaging of multiple conducting cylinders

Inverse scattering for multiple conducting cylinders is investigated. It is assumed that a plane wave is incident upon separate perfectly conducting cylinders of unknown shapes and the scattered field is measured outside, then, using prior knowledge of the rough positions of the scatterers, the shapes of the conducting scatterers can be reconstructed. The Newton-Kanotrovitch method is employed to solve nonlinear integral equations and the pseudoinverse technique is used to overcome the ill-posedness. Numerical examples are given to demonstrate the capability of the inversion algorithm. Good reconstruction is obtained even when the multiple scattering between two conductors is serious. The effect of noise on the reconstruction result is also investigated