A multi-verse optimizer approach for feature selection and optimizing SVM parameters based on a robust system architecture

Neural Computing and Applications - Support vector machine (SVM) is a well-regarded machine learning algorithm widely applied to classification tasks and regression problems. SVM was founded based...     

Lattice-Dome Design Using a Knowledge-Based System Approach

In the design of lattice domes, design engineers need expertise in areas such as configuration processing, nonlinear analysis, and optimization. These are extensive numerical, iterative, and time-consuming processes that are prone to error without an integrated design tool. This article presents the application of a knowledge-based system in solving lattice-dome design problems. An operational prototype knowledge-based system, LADOME, has been developed by employing the combined knowledge representation approach, which uses rules, procedural methods, and an object-oriented blackboard concept. The system's objective is to assist engineers in lattice-dome design by integrating all design tasks into a single computer-aided environment with implementation of the knowledge-based system approach. For system verification, results from design examples are presented.     

Thermal Behavior of a Multi-layered Thin Slab Carrying Periodic Signals Under the Effect of the Dual-Phase-Lag Heat Conduction Model

The thermal behavior of a two–layered thin slab carrying periodic signals under the effect of the dual-phase-lag heat conduction model is investigated. Two types of periodic signals are considered, a periodic heating source and a periodic imposed temperature at the boundary. The deviations among the predictions of the classical diffusion model, the wave mode, and the dual-phase-lag model are investigated. Analytical closed-form solutions are obtained for the temperature distribution within the slab. The effect of the angular frequency, thickness of the plate, dimensionless thermal relaxation time, dimensionless phase-lag in temperature gradient, thermal conductivity, and thermal diffusivity on the temperature distribution of the slab was studied. It is found that the deviations among the three models increase as the frequency of the signals increases and as the thickness of the plate decreases. It is found that the use of the dual-phase-lag heat conduction model is necessary when the metal film thickness is of order 10^–6 m and the angular frequency of the signals is of order 10¹²rad · s^–1.     

Utilization of oil-contaminated sands in asphalt concrete for secondary roads

The oil well sabotage during the Iraqi occupation and following the Iraqi withdrawal contaminated the Kuwaiti desert with crude oil covering millions of square meters. Thus, the desert has a huge amount of oil-contamined sand that must be cleaned up or treated in order to restore it to its natural beauty. The oil-contaminated sand was utilized to mix asphalt concrete in the laboratory to determine the feasibility of using sand contaminated with oil as feed stock in theproduction of asphalt construction materials. The products developed in experimental testing did meet international standards. The mixes were asphalt concrete of a quality that can be used for secondary roads, road beds, road subbases, impermeable layers for landfill and containment facilities, or as stabilizers for steep embankments. Gases emitted during the production of asphalt concrete utilizing oil-polluted sands are considered environmentally acceptable. Further studies are required to determine the feasibility of producing asphalt concrete from oil-contaminated sand on a pilot-plant scale as a means of utilizing the millions of square meters of oil-polluted sand.     

Soft computing methodologies for estimation of energy consumption in buildings with different envelope parameters

In this study, soft computing methods are designed and adapted to estimate energy consumption of the building according to main building envelope parameters such as material thicknesses and insulation K-value. In order to predict the building energy consumption, novel intelligent soft computing schemes, support vector regression (SVR), and adaptive neuro-fuzzy inference system (ANFIS) are used. The polynomial, linear, and radial basis function (RBF) is applied as the kernel function of the SVR to estimate the optimal energy consumption of buildings. The performance of proposed optimizers is confirmed by simulation results. The SVR results are compared with the ANFIS, artificial neural network (ANN), and genetic programming (GP) results. The computational results show that an improvement in predictive accuracy and capability of generalization can be achieved by the ANFIS approach in comparison to the SVR estimation. Based on the simulation results, the effectiveness of the proposed optimization strategies is verified. The data used in soft computing were obtained from 180 simulations in EnergyPlus for variations of building envelope parameters.     

Ammonia gas permeability of meat packaging materials

Meat products are packaged in polymer films designed to protect the product from exterior contaminants such as light, humidity, and harmful chemicals. Unfortunately, there is almost no data on ammonia permeability of packaging films. We investigated ammonia permeability of common meat packaging films: low-density polyethylene (LDPE; 2.2 mil), multilayer polyolefin (MLP; 3 mil), and vacuum (V-PA/PE; 3 mil, 0.6 mil polyamide/2.4 mil polyethylene). The films were fabricated into 10 × 5 cm pouches and filled with 50 mL deionized water. Pouches were placed in a plexiglass enclosure in a freezer and exposed to 50, 100, 250, or 500 ppm ammonia gas for 6, 12, 24, and 48 h at -17 ± 3 °C and 21 ± 3 °C. At freezing temperatures, no ammonia residues were detected and no differences in pH were found in the water. At room temperature, ammonia levels and pH of the water increased significantly (P < 0.05) with increasing exposure times and ammonia concentrations. Average ammonia levels in the water were 7.77 ppm for MLP, 5.94 ppm for LDPE, and 0.89 ppm for V-PA/PE at 500 ppm exposure for 48 h at 21 ± 3 °C. Average pH values were 8.64 for MLP, 8.38 for LDPE, and 7.23 for V-PA/PE (unexposed ranged from 5.49 to 6.44) at 500 ppm exposure for 48 h. The results showed that temperature influenced ammonia permeability. Meat packaging materials have low ammonia permeability and protect meat products exposed to ammonia leaks during frozen storage.     

A 1-Mbit MRAM based on 1T1MTJ bit cell integrated with copper interconnects

A low-power 1-Mb magnetoresistive random access memory (MRAM) based on a one-transistor and one-magnetic tunnel junction (1T1MTJ) bit cell is demonstrated. This is the largest MRAM memory demonstration to date. In this circuit, the magnetic tunnel junction (MTJ) elements are integrated with CMOS using copper interconnect technology. The copper interconnects are cladded with a high-permeability layer which is used to focus magnetic flux generated by current flowing through the lines toward the MTJ devices and reduce the power needed for programming. The 25-mm/sup 2/ 1-Mb MRAM circuit operates with address access times of less than 50 ns, consuming 24 mW at 3.0 V and 20 MHz. The 1-Mb MRAM circuit is fabricated in a 0.6-/spl mu/m CMOS process utilizing five layers of metal and two layers of poly.     

Treatment and prophylaxis of disseminated Mycobacterium avium complex in HIV-infected individuals

OBJECTIVE: To review the pathophysiology, epidemiology, treatment, and prophylaxis of disseminated Mycobacterium avium complex (MAC) infection in HIV-infected individuals. DATA SOURCES: A MEDLINE (January 1966-July 1997) and AIDSLINE (January 1980-July 1997) search of basic science articles pertinent to the MAC infection in HIV-infected patients. STUDY SELECTION AND DATA EXTRACTION: All articles were considered for possible inclusion in the review. Pertinent information, as judged by the authors, was selected for discussion. DATA SYNTHESIS: The organism, epidemiology, and pathophysiology of disseminated MAC are discussed for background. A review of clinical trials for the treatment and prophylaxis of disseminated MAC are presented, along with unresolved issues concerning these topics. CONCLUSIONS: The incidence of disseminated MAC has increased dramatically with the AIDS epidemic. The infection can lead to increased morbidity and mortality in HIV-infected patients. Treatment regimens for patients with a positive culture for MAC from a sterile site should include two or more drugs, including clarithromycin. Prophylaxis against disseminated MAC should be considered for patients with a CD4 cell count of less than 50/mm3.