Multiple-Input Multiple-Output Gaussian Broadcast Channels with Common and Confidential Messages

This paper considers the problem of the multiple-input multiple-output (MIMO) Gaussian broadcast channel with two receivers (receivers 1 and 2) and two messages: a common message intended for both receivers and a confidential message intended only for receiver 1 but needing to be kept asymptotically perfectly secure from receiver 2. A matrix characterization of the secrecy capacity region is established via a channel enhancement argument. The enhanced channel is constructed by first splitting receiver 1 into two virtual receivers and then enhancing only the virtual receiver that decodes the confidential message. The secrecy capacity region of the enhanced channel is characterized using an extremal entropy inequality previously established for characterizing the capacity region of a degraded compound MIMO Gaussian broadcast channel.Comment: Submitted to the IEEE Transactions on Information Theory, July 200

Triangular Bézier Surfaces with Approximate Continuity

When interpolating a data mesh using triangular Bézier patches, the requirement of C¹ or G¹ continuity imposes strict constraints on the control points of adjacent patches. However, fulfillment of these continuity constraints cannot guarantee that the resulting surfaces have good shape. This thesis presents an approach to constructing surfaces with approximate C¹/G¹ continuity, where a small amount of discontinuity is allowed between surface normals of adjacent patches. For all the schemes presented in this thesis, although the resulting surface has C¹/G¹ continuity at the data vertices, I only require approximate C¹/G¹ continuity along data triangle boundaries so as to lower the patch degree. For functional data, a cubic interpolating scheme with approximate C¹ continuity is presented. In this scheme, one cubic patch will be constructed for each data triangle and upper bounds are provided for the normal discontinuity across patch boundaries. For a triangular mesh of arbitrary topology, two interpolating parametric schemes are devised. For each data triangle, the first scheme performs a domain split and constructs three cubic micro-patches; the second scheme constructs one quintic patch for each data triangle. To reduce the normal discontinuity, neighboring patches across data triangle boundaries are adjusted to have identical normals at the middle point of the common boundary. The upper bounds for the normal discontinuity between two parametric patches are also derived for the resulting approximate G¹ surface. In most cases, the resulting surfaces with approximate continuity have the same level of visual smoothness and in some cases better shape quality

Theorizing to improve mental health in multicultural construction industries : an intercultural coping model

Construction workers are exposed to a range of stressors that lead to mental ill-health. In a multicultural construction workplace, the interactions between workers with different cultural backgrounds may aggravate mental health issues. Existing studies on coping typically focus on a reactive approach to managing stressors in the absence of cultural-related factors. This approach is inadequate in addressing mental health issues in a culturally diverse construction workplace. This paper presents a critical review that synthesizes and analyses theories and models of stress and coping, proactive coping, occupational stress, acculturative stress, and intercultural competence to develop a conceptual model for managing mental health in a multicultural construction workforce. The proposed model relies upon a positive coping mechanism, i.e., intercultural coping, to manage stressful events during the entire coping process in a multicultural workplace, towards achieving sustained good mental health. The proposed conceptual model contributes to the development of coping theories and positive psychology approaches and provides effective coping strategies to enhance psychological well-being in a multicultural context

DDT: Dual-branch Deformable Transformer for Image Denoising

Transformer is beneficial for image denoising tasks since it can model long-range dependencies to overcome the limitations presented by inductive convolutional biases. However, directly applying the transformer structure to remove noise is challenging because its complexity grows quadratically with the spatial resolution. In this paper, we propose an efficient Dual-branch Deformable Transformer (DDT) denoising network which captures both local and global interactions in parallel. We divide features with a fixed patch size and a fixed number of patches in local and global branches, respectively. In addition, we apply deformable attention operation in both branches, which helps the network focus on more important regions and further reduces computational complexity. We conduct extensive experiments on real-world and synthetic denoising tasks, and the proposed DDT achieves state-of-the-art performance with significantly fewer computational costs.Comment: The code is avaliable at: https://github.com/Merenguelkl/DD

Optimization of extraction of polyphenols from Sorghum Moench using response surface methodology, and determination of their antioxidant activities

Purpose: To employ response surface methodology (RSM) hinged on a central composite design (CCD) for the optimization of the extraction of polyphenols from Sorghum moench (Sorghum M).Methods: The combined influence of independent variables were assessed with RSM. Total phenolic content (TPC) determination was carried out using Folin-Ciocalteu method. Derivative compounds of phenolic acid were assayed using high performance liquid (HPLC). Antioxidant potential was determined through 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging test.Results: The optimized extraction conditions were: 60.37 % ethanol, temperature of 59.07 oC and 2.97 h of extraction duration, which resulted in the extraction of maximum amount of TPC, i.e., 313 mg GAE/100g dry weight. The interactions between temperature and ethanol concentration, and between extraction time and ethanol concentration had significant effects of TPC (p < 0.05). Under these conditions, there was a consistency between the projected and actual experimental levels of polyphenols. A positive correlation was found between TPC and DPPH radical scavenging activity (r=0.67, p <0.05). Furthermore, ferulic acid correlated positively with p-coumaric acid (r = 0.54, p <0.01).Conclusion: These results underscore the usefulness of conditions for extraction in accuratequantification of antioxidants and phenolic compounds from Sorghum M, for possible application in large scale commercial extraction.Keywords: Response surface methodology, Sorghum moench, Polyphenols, Antioxidant

Stressors in the multicultural construction working environment

Due to the dynamic and complex nature of the construction industry, construction workers are often exposed to a range of stressors which are causative factors for mental health problems. Simultaneously, intercultural contact between workers in a multicultural working environment may aggravate mental health issues. A better understanding of stressors can contribute to the development of targeted measures for mental health prevention and promotion. Therefore, this study aims to investigate the correlation between stressors and mental health for construction workers in a culturally diverse working environment. Data were collected using questionnaires from 252 construction workers in Australia. The Pearson correlation analysis was used to analyse the collected data. The results revealed the significant correlations between stressors and mental health outcomes and indicated the most significant stressors from work, personal and cultural domains. The findings provide valuable insights for practitioners and policymakers on the development of mental health interventions for construction workforce in a multicultural context. Researchers could also benefit from an in-depth comprehension on the causative factors of psychological issues in the construction industry

Coping strategies for work and cultural stressors in multicultural construction workplaces : a study in Australia

Existing coping theories typically position coping as a reactive approach to managing mental health. Intercultural coping was proposed to positively deal with stressors and alleviate the negative impacts of stressors on mental health outcomes in multicultural workplaces. This study aims to investigate the role of intercultural coping strategies in influencing the relationships between stressors and mental health outcomes in multicultural construction workplaces. Data were collected from 252 construction workers in Australia using online questionnaire survey. Data were analysed using the structural equation modelling (SEM) technique. The results revealed the moderating effect of positive coping strategies on the stressor-psychological outcome relationship. A worker who is open to cultural dissimilarity tends to suffer less the adverse effect of cultural stressors on mental health. A worker with cognitive complexity is less susceptible to the adverse impact of work stressors on mental health. Whereas, a worker who is performance-oriented is more vulnerable to the impact of work stressors on mental health. This study may contribute to the existing body of work by uncovering the moderating role of positive coping strategies and providing targeted and effective coping strategies in multicultural construction workplaces

Microstructural and Mechanical Performance of Al2O3 Nanoparticle Reinforced 17-4 PH Stainless Steel Bulk Composite Parts Fabricated by Laser Engineered Net Shaping Process

Alloy 17-4 PH (AISI 630) is a precipitation-hardening martensitic stainless steel that has been extensively employed in the industries of aerospace, marine, and chemical. In this study, bulk parts of both 17-4 PH and Al2O3 reinforced 17-4 PH composites were fabricated on a steel substrate by laser engineered net shaping (LENS) process to investigate the effects of Al2O3 reinforcements on the part performance. The 17-4 PH powders were pre-mixed with Al2O3 nanoparticles by ball milling. The microstructures of both parts were observed using scanning electron microscopy and mechanical properties including microhardness and compressive properties were evaluated by means of a Vickers microhardness tester and a universal tester, respectively. The results indicate that Al2O3 reinforced 17-4 PH composite parts fabricated by LENS process exhibited superior microhardness and compressive properties as compared to pure 17-4 PH parts.Mechanical Engineerin