Modelling the intermixing effects in highly strained asymmetric InGaAs/GaAs quantum well

In this work, we have theoretically investigated the intermixing effect in highly strained In$_{0.3}$Ga$_{0.7}$As/GaAs quantum well (QW) taking into consideration the composition profile change resulting from in-situ indium surface segregation. To study the impact of the segregation effects on the postgrowth intermixing, one dimensional steady state Schrodinger equation and Fick's second law of diffusion have been numerically solved by using the finite difference methods. The impact of the In/Ga interdiffusion on the QW emission energy is considered for different In segregation coefficients. Our results show that the intermixed QW emission energy is strongly dependent on the segregation effects. The interdiffusion enhanced energy shift is found to be considerably reduced for higher segregation coefficients. This work adds a considerable insight into the understanding and modelling of the effects of interdiffusion in semiconductor nanostructures.Comment: 6 pages, 4 figure

Controlling a drone: Comparison between a based model method and a fuzzy inference system

International audienceThe work describes an automatically on-line self-tunable fuzzy inference system (STFIS) of a new configuration of mini-flying called XSF (X4 Stationnary Flyer) drone. A fuzzy controller based on on-line optimization of a zero order Takagi-Sugeno fuzzy inference system (FIS) by a back propagation-like algorithm is successfully applied. It is used to minimize a cost function that is made up of a quadratic error term and a weight decay term that prevents an excessive growth of parameters. Thus, we carried out control for the continuation of simple trajectories such as the follow-up of straight lines, and complex (half circle, corner, and helicoidal) by using the STFIS technique. This permits to prove the effectiveness of the proposed control law. Simulation results and a comparison with a static feedback linearization controller (SFL) are presented and discussed. We studied the robustness of the two controllers used in the presence of disturbances. We presented two types of disturbances, the case of a breakdown of an engine as well as a gust of wind

Sub-graph based joint sparse graph for sparse code multiple access systems

Sparse code multiple access (SCMA) is a promising air interface candidate technique for next generation mobile networks, especially for massive machine type communications (mMTC). In this paper, we design a LDPC coded SCMA detector by combining the sparse graphs of LDPC and SCMA into one joint sparse graph (JSG). In our proposed scheme, SCMA sparse graph (SSG) defined by small size indicator matrix is utilized to construct the JSG, which is termed as sub-graph based joint sparse graph of SCMA (SG-JSG-SCMA). In this paper, we first study the binary-LDPC (B-LDPC) coded SGJSG- SCMA system. To combine the SCMA variable node (SVN) and LDPC variable node (LVN) into one joint variable node (JVN), a non-binary LDPC (NB-LDPC) coded SG-JSG-SCMA is also proposed. Furthermore, to reduce the complexity of NBLDPC coded SG-JSG-SCMA, a joint trellis representation (JTR) is introduced to represent the search space of NB-LDPC coded SG-JSG-SCMA. Based on JTR, a low complexity joint trellis based detection and decoding (JTDD) algorithm is proposed to reduce the computational complexity of NB-LDPC coded SGJSG- SCMA system. According to the simulation results, SG-JSGSCMA brings significant performance improvement compare to the conventional receiver using the disjoint approach, and it can also outperform a Turbo-structured receiver with comparable complexity. Moreover, the joint approach also has advantages in terms of processing latency compare to the Turbo approaches

Designing Successful Strategy for Business Process Outsourcing Based on Ontological Knowledge Map

Business process outsourcing (BPO) is an advanced type of IS outsourcing. This study will investigate the obstacles and challenges of BPO Industry. One of the most important problem in this area is identifying existing explicit knowledge and using it to create further knowledge for decision making, so deep investigation on a conceptual model is needed that helps realize the complexities of outsourcing areas especially for business process outsourcing. Most of outsourcing literature has focused on social and cultural impacts and very few tools have been developed to assist manager in making outsourcing decision by modelling the knowledge. In this paper we propose a methodology for modelling the knowledge of a domain in small and medium size enterprises (SMEs). This methodology is based on ontological knowledge map. Findings of this research overcome these obstacles through the use of a formal organizational ontology and knowledge structure maps. The ontology guides decision makers in managing the complexity of outsourcing with holistic approach to the domain of outsourcing. Ontologies as a conceptual model provide a framework to facilitate efficient and effective knowledge-sharing, knowledge reusing and improving communication by modelling the domain of discourse. Keywords: business process outsourcing, ontology, knowledge ma

Un algorithme pour la planification de trajectoire basé sur le calcul ensembliste

National audienceNous proposons dans cet article une solution originale et garantie à la "planification de trajectoire" en utilisant une approche ensembliste. Le système est capable de traiter des tâches compliquées dans un environnement encombré d'obstacles, avec pour seule entrée la géométrie de l'e nvironnement, un point de départ et un point d'arrivée. La tâche de planification est résolue en combinant le calcul par intervalle et la théorie des graphes. La méthode est illustrée sur un cas idéalisé dans lequel le robot est choisi circulaire et les obstacles composés de figures géométriques simples

Image Retrieval System in Heterogeneous Database

Non