In this paper, we investigate the use of a self-adaptive Pareto evolutionary multi-objective optimization (EMO) approach for evolving the controllers of virtual embodied organisms. The objective of this paper is to demonstrate the trade-off between quality of solutions and computational cost. We show empirically that evolving controllers using the proposed algorithm incurs significantly less computational cost when compared to a self-adaptive weighted sum EMO algorithm, a self-adaptive single-objective evolutionary algorithm (EA) and a hand-tuned Pareto EMO algorithm. The main contribution of the self-adaptive Pareto EMO approach is its ability to produce sufficiently good controllers with different locomotion capabilities in a single run, thereby reducing the evolutionary computational cost and allowing the designer to explore the space of good solutions simultaneously. Our results also show that self-adaptation was found to be highly beneficial in reducing redundancy when compared against the other algorithms. Moreover, it was also shown that genetic diversity was being maintained naturally by virtue of the system's inherent multi-objectivity.
Solar cells are considered one of the most important and widespread solar applications in the world. However, the performance of the PV modules is significantly affected by the dust in the air. This paper, therefore, presents a comparison of an outdoor experimental study of dust effect on monocrystalline, and polycrystalline photovoltaic (PV) modules. For analysis, four 100 W PVs were installed horizontally in Sohar, Oman. For each pair of PV modules, one was left dusty due to environmental impact, and the second was cleaned daily. PV performance and environmental parameter measurements were conducted every 30 min for 35 days. The effects of dust on current, voltage, power, and energy were discussed in terms of time and normalized values. Also, cleaning methods were tested to determine the optimum one. It is found that power degradation of monocrystalline (20%) is higher compared with polycrystalline (12%) due to dust accumulation. For monocrystalline, the current, voltage, and power losses ranged between 10.0-24.0%, 2.0-3.5%, and 14.0-31.0%, respectively. However, for polycrystalline, the degradation rates were 16.88-27.92%, 0.455-0.455%, and 17.14-28.1% for current, voltage, and power losses after exposure to outdoor conditions for the same period, respectively. The dust accumulation on the PV surface found after 5 weeks is 0.493 mg/cm2, which can be considered the lowest accumulation rate compared to other Gulf countries, but which, however, leads to less energy degradation as well. It is found that water is sufficient to clean PV in the study area. However, sodium detergent as a cleaner introduced better results compared to water, especially when there is high pollution in the location.
The bi-fluid photovoltaic thermal (PVT) collector was introduced to provide more heating options along with improved cooling capabilities for the PV module. Since its introduction, this type of PVT system has been investigated thoroughly in various original works. In this review paper, we intend to put the concept and applications of this technology into question and revise the main achievements and discoveries through research and development with a focus on climatic and operational parameters. The paper encompasses a critical review of the discussed research and future directions for PVT collectors. The main utilized operational modes are discussed in detail, which are (i) water used in both channels, (ii) water in one channel and air in the other, and (iii) air in both channels. The modes were found to lead to different enhancement and performance effects for the utilized photovoltaic modules. The impact of mass flow rate was also taken by keeping one working fluid constant while varying the other to obtain its impact on the energy and exergy efficiency of the collector. In some cases, the fluids were run simultaneously and, in other cases, independently.
Cavernous sinus thrombosis (CST) is an ocular emergency because of its devastating effect and it is prone to cause serious complications. Diagnosis of cavernous sinus thrombosis is a challenging task despite medical advancement. Efforts to promptly diagnose and initiate treatment require a high index of suspicion and a deep understanding of the disease. Unfortunately, patients suffering from CST may not always present with typical symptoms, thus making diagnosis all the more challenging. We would like to describe a 22-year-old man who presented with atypical symptoms and radiological presentations of CST. The patient was admitted and treated in our institution with full recovery demonstrated after the treatment.
Orbital myositis in children is uncommon. Recurrence is a major challenge in management. An 11-year-old Malay girl who presented with bilateral orbital myositis with recurrent attacks of diplopia is reported.
Although they originated from China, Malays have undergone a lot of intermarriages. A study suggested that CYP2D6 poor metabolism (PM) phenotype was more common in Malays compared to Chinese. CYP2D6 is highly polymorphic and is involved in the metabolism of many drugs and has been implicated in some environmentally-induced diseases. It is therefore useful to further study this polymorphism in Malays.
Measurements of environmental terrestrial gamma radiation dose-rate (TGRD) have been made in Johore, Malaysia. The focus is on determining a relationship between geological type and TGRD levels. Data were compared using the one way analysis of variance (ANOVA), in some instances revealing significant differences between TGRD measurements and the underlying geological structure.
Juvenile xanthogranuloma (JXG) is an uncommon condition affecting the eye. We herein report a rare case of eyelid swelling in paediatric age group. A three-year-old Malay boy presented with chronic painless left upper eyelid mass which did not resolve with topical steroid. Clinically, the mass was a non-tender and firm nodular swelling which located at the lateral 1/3 of the left upper lid. Total excisional biopsy of the swelling was done and histopathological findings were consistent with JXG. The systemic associations and the treatment options for ocular JXG are discussed.
To assess the knowledge, attitudes and experience of a group of Malaysian dental health care providers regarding child physical abuse (CPA) cases in terms of frequency of occurrence, diagnosis, risk factors and reporting.
A diver presented with total loss of vision in the left eye and right hemiparesis following a routine no-stop scuba dive to 20 metres' depth. A diagnosis of decompression illness (DCI) with acute ophthalmic artery air embolism and left carotid artery insult causing acute anterior circulatory ischaemia was made. He underwent seven hyperbaric treatments leading to a full recovery. Magnetic resonance angiography revealed an underlying left anterior cerebral artery A1 segment hypoplasia. Making a prompt diagnosis and early hyperbaric oxygen treatment are crucial to halt further tissue damage from ischaemia in central nervous system DCI. In this case, the finding of a left A1 anterior cerebral artery segment hypoplasia variant may have increased the severity of DCI due to deficient collateral circulation.
A 30-year-old Bangladeshi gentleman presented with history of sand entering his left eye and was diagnosed as having fungal keratitis by private ophthalmologist. He was treated with three doses of conventional subconjunctival amphotericin B injections (1.5 mg of amphotericin B and 1.2 mg of deoxycholate) over the inferior bulbar conjunctiva and topical antibiotics. Subsequently, he developed conjunctival necrosis over the site of injections and there was no clinical improvement of the keratitis. He was then treated with intensive antifungal and antibiotics eye drops. Debridement of epithelial plug was done and he was given intracameral amphotericin B injection. There was gradual improvement observed then with conjunctival epithelialization. The conjunctival tissue was completely healed after three months along with the corneal ulcer. Subconjunctival injection of Amphotericin B (AMB) may be considered as an adjunct therapy in severe fungal keratitis to address the issue of compliance. Close monitoring is needed due to its known complication of scleritis, scleral thinning and conjunctival necrosis. Liposomal AMB which is known to cause less toxicity given via subconjunctival injection in human subjects needs to be further studied.
A 43 year-old man presented with pain on the right tooth for three days duration. Computed tomography showed left orbital cellulitis and right parapharyngeal abscess. There was also evidence suggestive of a dental abscess over right upper alveolar region. Magnetic resonance imaging revealed left superior ophthalmic vein thrombosis. Emergency drainage of the right parapharyngeal abscess was performed. Right maxillary molar extraction revealed periapical abscess. Left eye proptosis markedly reduced after initiating heparin.
With the development of communication technologies, the use of wireless systems in biomedical implanted devices has become very useful. Bio-implantable devices are electronic devices which are used for treatment and monitoring brain implants, pacemakers, cochlear implants, retinal implants and so on. The inductive coupling link is used to transmit power and data between the primary and secondary sides of the biomedical implanted system, in which efficient power amplifier is very much needed to ensure the best data transmission rates and low power losses. However, the efficiency of the implanted devices depends on the circuit design, controller, load variation, changes of radio frequency coil's mutual displacement and coupling coefficients. This paper provides a comprehensive survey on various power amplifier classes and their characteristics, efficiency and controller techniques that have been used in bio-implants. The automatic frequency controller used in biomedical implants such as gate drive switching control, closed loop power control, voltage controlled oscillator, capacitor control and microcontroller frequency control have been explained. Most of these techniques keep the resonance frequency stable in transcutaneous power transfer between the external coil and the coil implanted inside the body. Detailed information including carrier frequency, power efficiency, coils displacement, power consumption, supplied voltage and CMOS chip for the controllers techniques are investigated and summarized in the provided tables. From the rigorous review, it is observed that the existing automatic frequency controller technologies are more or less can capable of performing well in the implant devices; however, the systems are still not up to the mark. Accordingly, current challenges and problems of the typical automatic frequency controller techniques for power amplifiers are illustrated, with a brief suggestions and discussion section concerning the progress of implanted device research in the future. This review will hopefully lead to increasing efforts towards the development of low powered, highly efficient, high data rate and reliable automatic frequency controllers for implanted devices.
In this work, landfill leachate treatment by electrocoagulation process with a novel rotating anode reactor was studied. The influence of rotating anode speed on the removal efficiency of chemical oxygen demand (COD), total dissolved solids (TDS), and total suspended solids (TSS) of raw landfill leachate was investigated. The influence of operating parameters like leachate pH, leachate temperature, current, and inter-distance between the cathode rings and anode impellers on the electrocoagulation performance were also investigated. The results revealed the optimum rotating speed is 150 rpm and increasing the rotating speed above this value led to reducing process performance. The leachate electrocoagulation treatment process favors the neutral medium and the treatment performance increases with increasing current intensity. Furthermore, the electrocoagulation treatment performance improves with increasing leachate temperature. However, the performance reduces with increasing inter-electrode distance.
Friction and wear are the main factors in the failure of the piston in automobile engines. The objective of this work was to improve the tribological behaviour and lubricant properties using hybrid Cellulose Nanocrystal (CNC) and Copper (II) oxide nanoparticles blended with SAE 40 as a base fluid. The two-step method was used in the hybrid nanofluid preparation. Three different concentrations were prepared in a range of 0.1% to 0.5%. Kinematic viscosity and viscosity index were also identified. The friction and wear behavior were evaluated using a tribometer based on ASTM G181. The CNC-CuO nano lubricant shows a significant improvement in term of viscosity index by 44.3-47.12% while for friction, the coefficient of friction (COF) decreases by 1.5%, respectively, during high and low-speed loads (boundary regime), and 30.95% during a high-speed, and low load (mixed regime). The wear morphologies results also show that a smoother surface was obtained after using CNC-CuO nano lubricant compared to SAE 40.
This paper evaluated a 1.4 kW grid-connected photovoltaic system (GCPV) using two neural network models based on experimental data for one year. The novelty of this study is to propose and compare full recurrent neural network (FRNN), and principal component analysis (PCA) models based on entire year experimental data, considering limited research conducted to predict GCPV behaviour using the two methods. The system data was collected for 12 months secondly and hourly data with 50400 samples daily. The GCPV evaluates using specific yield, energy cost, capacity factor, payback period, current, voltage, power, and efficiency. The predicted GCPV current and power using FRNN and PCA were evaluated and compared with measured values to validate results. However, the results indicated that FRNN is better in simulating the experimental results curve compared with PCA. The measured and predicted data are compared and evaluated. It is found that the GCPV is suitable and promising for the study area in terms of technical and economic evaluation with a 3.24-4.82 kWh/kWp-day yield, 21.7% capacity factor, 0.045 USD/kWh cost of energy, and 11.17 years payback period.
Molar-incisor hypomineralisation (MIH) is a global dental problem, yet little is known about the knowledge of the general dental practitioners (GDPs) and dental nurses (DNs) regarding this defect in South East Asia.
Azoospermia factor region (AZF) deletions (AZFa, AZFb, AZFc and AZFd) in the Y chromosome were analysed in male infertility subjects in various populations with conflicting results. This study comprised of 54 infertile males and 63 fertile controls, and the frequency of AZFa, AZFb, AZFc and AZFd deletions were determined using conventional polymerase chain reaction (PCR) as well as real-time PCR-high resolution melting analysis-based methods. The results of this study showed that, three of 54 cases (5.55%) had AZF (a, b and c) deletions (two had AZFc and one had AZFa deletions). Four cases were found to have AZFd deletions (7.4%) with two of them being associated with AZFc deletions (P = 0.028). The frequency of AZF (a, b and c) deletions in Malaysian infertile male subjects was found to be comparable with other populations. AZFd deletions were found to be significant (P < 0.05) in male infertility and it may be associated with other types of AZF deletions.
Concentrations of uranium-238 and thorium-232 in soil, water, grass, moss and oil-palm fruit samples collected from an area of high background radiation were determined using neutron activation analysis (NAA). U-238 concentration in soil ranged from 4.9 mg kg(-1) (58.8 Bq kg(-1)) to 40.4 mg kg(-1) (484.8 Bq kg(-1)), Th-232 concentration ranged from 14.9 mg kg(-1) (59.6 Bq kg(-1)) to 301.0 mg kg(-1) (1204 Bq kg(-1)). The concentration of U-238 in grass samples ranged from below the detection limit to 0.076 mg kg(-1) (912 mBq kg(-1)), and Th-232 ranged from 0.008 mg kg(-1) (32 mBq kg(-1)) to 0.343 mg kg(-1) (1.372 Bq kg(-1)). U-238 content in water samples ranged from 0.33 mg kg(-1) (4.0 Bq L(-1)) to 1.40 mg kg(-1) (16.8 Bq L(-1)), and Th-232 ranged from 0.19 mg kg(-1) (0.76 Bq L(-1)) to 0.66 mg kg(-1) (2.64 Bq L(-1)). It can be said that the concentrations of environmental U-238 and Th-232 in grass and water samples in the study area are insignificant. Mosses were found to be possible bio-radiological indicators due to their high absorption of the heavy radioelements from the environment.
Molar-Incisor Hypomineralization (MIH) is a condition of hypomineralized enamel of systemic origin affecting first permanent molars and frequently permanent incisors. It is considered a global problem and data from South-East Asian countries, including Malaysia are lacking. Hence the aim of this study were to investigate the distribution and severity of MIH in a group of children aged 7-12 year olds attending pediatric dental clinic at Faculty of Dentistry, Universiti Teknologi MARA (UiTM), Malaysia.