Complexity science for sleep stage classification from EEG

Automatic sleep stage classification is an important paradigm in computational intelligence and promises consider- able advantages to the health care. Most current automated methods require the multiple electroencephalogram (EEG) chan- nels and typically cannot distinguish the S1 sleep stage from EEG. The aim of this study is to revisit automatic sleep stage classification from EEGs using complexity science methods. The proposed method applies fuzzy entropy and permutation entropy as kernels of multi-scale entropy analysis. To account for sleep transition, the preceding and following 30 seconds of epoch data were used for analysis as well as the current epoch. Combining the entropy and spectral edge frequency features extracted from one EEG channel, a multi-class support vector machine (SVM) was able to classify 93.8% of 5 sleep stages for the SleepEDF database [expanded], with the sensitivity of S1 stage was 49.1%. Also, the Kappa’s coefficient yielded 0.90, which indicates almost perfect agreement

Prevalence, causes and consequences of intimate partner violence in Saudi Arabia: a scoping review

Intimate partner violence (IPV) is highly prevalent in many countries, including Saudi Arabia. Studies have shown that 1 in every 10 women in Saudi Arabia is a victim of IPV. This is slightly lower than the prevalence of IPV in the WHO African, Eastern Mediterranean, and South-East Asia Regions, where approximately 37% of women in long-term partnerships report having experienced physical and sexual IPV during their lifetime. This review identified and analyzed the available empirical studies that explore IPV in Saudi Arabia. Nineteen (n = 19) studies were retrieved from three databases, including Medline, CINAHL, and PsycINFO, as well as Google and Google Scholar. Only empirical studies published in the English language and involving Saudi Arabian citizens were examined. We identified 13 studies that explored the prevalence of IPV and 11 studies that discussed factors associated with IPV. Eight studies examined the effects and consequences of IPV, six studies reported attitudes, perceptions, and knowledge related to IPV, and only three studies investigated victim response to IPV. Nineteen studies included women and only one study involved men as research participants. The findings suggest that previous studies undertaken in Saudi Arabia used quantitative approaches and gathered data via questionnaires, and therefore participants were not given the chance to describe how they defined different forms of IPV. More specifically, previous studies failed to explore the problem of IPV through the lens of Saudi men, creating a research gap related to defining their attitudes and perceptions of this phenomenon

Nanosecond pulsed laser texturing of optical diffusers

High-quality optical glass diffusers have applications in aerospace, displays, imaging systems, medical devices, and optical sensors. The development of rapid and accurate fabrication techniques is highly desirable for their production. Here, a micropatterning method for the fast fabrication of optical diffusers by means of nanosecond pulsed laser ablation is demonstrated (λ=1064 nm, power=7.02, 9.36 and 11.7 W and scanning speed=200 and 800 mm s-1). The experiments were carried out by point-to-point texturing of a glass surface in spiral shape. The laser machining parameters, the number of pulses and their power had significant effect on surface features. The optical characteristics of the diffusers were characterized at different scattering angles. The features of the microscale structures influenced average roughness from 0.8 μm to 1.97 μm. The glass diffusers scattered light at angles up to 20° and their transmission efficiency were measured up to ∼97% across the visible spectrum. The produced optical devices diffuse light less but do so with less scattering and energy losses as compared to opal diffusing glass. The presented fabrication method can be applied to any other transparent material to create optical diffusers. It is anticipated that the optical diffusers presented in this work will have applications in the production of LED spotlights and imaging devices

Laser inscription of pseudorandom structures for microphotonic diffuser applications

Optical diffusers provide a solution for a variety of applications requiring a Gaussian intensity distribution including imaging systems, biomedical optics, and aerospace. Advances in laser ablation processes have allowed the rapid production of efficient optical diffusers. Here, we demonstrate a novel technique to fabricate high-quality glass optical diffusers with cost-efficiency using a continuous CO2 laser. Surface relief pseudorandom microstructures were patterned on both sides of the glass substrates. A numerical simulation of the temperature distribution showed that the CO2 laser drills a 137 μm hole in the glass for every 2 ms of processing time. FFT simulation was utilized to design predictable optical diffusers. The pseudorandom microstructures were characterized by optical microscopy, Raman spectroscopy, and angle-resolved spectroscopy to assess their chemical properties, optical scattering, transmittance, and polarization response. Increasing laser exposure and the number of diffusing surfaces enhanced the diffusion and homogenized the incident light. The recorded speckle pattern showed high contrast with sharp bright spot free diffusion in the far field view range (250 mm). A model of glass surface peeling was also developed to prevent its occurrence during the fabrication process. The demonstrated method provides an economical approach in fabricating optical glass diffusers in a controlled and predictable manner. The produced optical diffusers have application in fibre optics, LED systems, and spotlights

Key Adoption Factors for Collaborative Technologies and Barriers to Information Management in Construction Supply Chains: A System Dynamics Approach

Construction processes are complex and dynamic. Like its other components, the construction supply chain (CSC) involves multiple stakeholders requiring varying levels of information sharing. In addition, the intensity and diversity of information in CSCs require dexterous management. Studies reveal that information complexity can be reduced using collaborative technologies (CTs). However, the barriers to information management (IM) hinder the CTs’ adoption process and cause complexity in CSCs. This research identifies barriers to IM and factors affecting the adoption of CTs in developing countries. In order to understand and address complexity, the system dynamics (SD) approach is adopted in this study. The aim is to investigate if SD can reduce information complexity using CTs. Causal loop diagrams (CLDs) were developed to understand the relationship between the IM barriers and CT adoption factors. The SD model, when simulated, highlighted three main components, i.e., complexity, top management support, and trust and cooperation, among others, as factors affecting the adoption of CTs. Addressing these factors will reduce information complexity and result in better IM in construction projects

A novel in-ear sensor to determine sleep latency during the Multiple Sleep Latency Test in healthy adults with and without sleep restriction

Objectives: Detecting sleep latency during the Multiple Sleep Latency Test (MSLT) using electroencephalogram (scalp-EEG) is time-consuming. The aim of this study was to evaluate the efficacy of a novel in-ear sensor (in-ear EEG) to detect the sleep latency, compared to scalp-EEG, during MSLT in healthy adults, with and without sleep restriction. Methods: We recruited 25 healthy adults (28.5±5.3 years) who participated in two MSLTs with simultaneous recording of scalp and in-ear EEG. Each test followed a randomly assigned sleep restriction (≤5 hours sleep) or usual night sleep (≥7 hours sleep). Reaction time and Stroop test were used to assess the functional impact of the sleep restriction. The EEGs were scored blind to the mode of measurement and study conditions, using American Academy of Sleep Medicine 2012 criteria. The Agreement between the scalp and in-ear EEG was assessed using Bland-Altman analysis. Results: Technically acceptable data were obtained from 23 adults during 69 out of 92 naps in the sleep restriction condition and 25 adults during 85 out of 100 naps in the usual night sleep. Meaningful sleep restrictions were confirmed by an increase in the reaction time (mean ± SD: 238±30 ms vs 228±27 ms; P=0.045). In the sleep restriction condition, the in-ear EEG exhibited a sensitivity of 0.93 and specificity of 0.80 for detecting sleep latency, with a substantial agreement (κ=0.71), whereas after the usual night’s sleep, the in-ear EEG exhibited a sensitivity of 0.91 and specificity of 0.89, again with a substantial agreement (κ=0.79). Conclusion: The in-ear sensor was able to detect reduced sleep latency following sleep restriction, which was sufficient to impair both the reaction time and cognitive function. Substantial agreement was observed between the scalp and in-ear EEG when measuring sleep latency. This new in-ear EEG technology is shown to have a significant value as a convenient measure for sleep latency

Modeling Profitability-Influencing Risk Factors for Construction Projects: A System Dynamics Approach

This study addressed the complexity involved in integrating the causative risk factors influencing construction profitability. Most of the existing studies cover the individual effects of profitability influencing factors. Very few focus on the systematic impact without incorporating the complexity and associated dynamics, presenting a gap targeted by the current study. The current study aimed to assess causative interrelations and interdependencies between profitability influencing risk factors (PIRF), through systems thinking (ST) and system dynamics (SD) modeling. The SD approach was used to evaluate the integrated impacts on profitability-influencing risk categories (PIRC) in construction projects. The causative influencing factors affecting construction profitability were identified through a comprehensive literature review. These were ranked using content analysis, and categorized into significant issues. Through 250 structured surveys and 15 expert opinion meetings, the path for quantitative and qualitative evaluations was prepared. Following these investigations, a causal loop diagram (CLD) was established using the ST technique, and the integrated effect was quantified using SD modeling. The study finds the rising cost of material, supply chain process, payment issues, planning and scheduling problems, financial difficulties, and effective control of manpower and equipment resources as the most critical PIRFs. The integrated effects of PIRFs on PIRC were quantified using SD modeling. This study helps field professionals with profitability-influencing factors, diagnosing issues, and integrating impacts regarding decision-making and policy formulation. For researchers, it presents a list of factors that can be investigated in detail, and the holistic interrelationships established

Key factors for implementation of total quality management in construction Sector: A system dynamics approach

Maintaining quality in construction projects is paramount to project success, achieved through techniques such as Total Quality Management (TQM). However, the key factors of TQM implementation in the construction industry of developing countries are not well explored. Accordingly, this paper evaluated the causative relationship and intricacies of TQM implementation in the construction sector of developing countries. A total of 28 key factors of TQM were captured through a literature review. Thereafter, 12 significant key factors were shortlisted. Lack of top management commitment, poor customer/client satisfaction, inadequate quality of education regarding TQM, and ineffective organizational quality culture emerged as impediments to implementing TQM in the construction sector. A Causal Loop Diagram (CLD) was developed to represent interrelations between the 12 shortlisted factors. In addition, a system dynamics model (SDM) was developed. The simulation results of the developed SDM indicated an increase in TQM implementation over the period under the defined system