A discrete electromagnetism-like mechanism for parallel machine scheduling under a grade of service provision

We consider the problem of minimising total weighted tardiness on identical parallel machines with grade of service eligibility. Due to the essential complexity of the problem, we apply an electromagnetism-like mechanism (EM), which is a novel metaheuristic, to solve the problem. In the proposed EM, the particle is redesigned to represent a valid assignment of jobs to machines. A distance measure between particles, called ‘1A2B’ distance, is proposed by the concept of a number guessing game. Then, the new attraction and repulsion operators are developed to move a particle to the new particle. To verify the proposed EM, computational experiments are conducted to make a comparison with a recent genetic algorithm (GA). The results show that the proposed EM has a good performance and outperforms the GA for the considered problem.     

Improvement of the RFID authentication scheme based on quadratic residues

RFID, with its capability of remote automatic identification, is taking the place of barcodes and becoming the new generation of electronic tags. However, information transmitted through the air is vulnerable to eavesdropping, interception, or modification due to its radio transmission nature; the prevalence of RFID has greatly increased security and privacy concerns. In 2008, Chen et al. proposed an RFID authentication scheme which can enhance security and privacy by using hash functions and quadratic residues. However, their scheme was found to be vulnerable to impersonation attacks. This study further demonstrates that their scheme does not provide location privacy and suffers from replay attacks. An improved scheme is also proposed which can prevent possible attacks and be applied in environments requiring a high level of security.     

The evaluation of intelligent agent performance — An example of B2C e-commerce negotiation

Increasing demand for sophisticated software capable to collaborate, control, and organize all distributed activities has encouraged researchers in various disciplines to utilize and implement Intelligent Agent (IA). This paper develops a methodology to appraise performance of the IA and demonstrate the use in the B2C e-commerce negotiation process. An experiment was conducted to acquire empirical data and a survey was implemented to confirm advantage of the use of the IA. The computational results indicate that the proposed approach successfully evaluates IA performance and significantly distinguishes groups of using (vs. not using) the negotiation mechanism in B2C e-commerce.     

AUTOMATIC INSPECTION SYSTEM FOR DEFECTS OF PRINTED ART TILE BASED ON TEXTURE FEATURE ANALYSIS

An automatic inspection system of printed art tile defects is reported in this artucke. After calculating eight defect features of art tile using the gray level co-occurrence matrix and the average R, G, B values of a defective area, the results were input into a backward propagation neural network for training the defect classifier. During inspection, the proposed system compared the inspected image with a standard image and removed noise by an erosion operation in order to preliminarily determine whether the art tile had defects. For the defective art tile images, the proposed classifier successfully identified four types of common printing defects. The proposed algorithm had an average recognition rate of 90%, suggesting that the recognition accuracy is good, and only requires 1–2 s to inspect an art tile with the size of 15 × 15 cm². The inspection speed is faster than the conventional manual inspection, and recognition results are more stable. The proposed system can reduce the risk of error caused by the long duration of manual inspection, and thus, can reduce manufacturing costs.     

Asymmetric porous membranes formed by coagulation-induced phase separation in poly(ether sulfone)/poly(vinyl pyrrolidone)/genistein blends

Development of asymmetric channel morphology driven by coagulation-induced phase separation of genistein (G) modified poly(ether sulfone)/poly(vinyl pyrrolidone) (PES/PVP) blends has been examined in relation to their miscibility phase diagram. PES/G pairs turned out to be miscible in the amorphous state, whereas solid–liquid phase separation occurred at high genistein compositions. The solid–liquid phase diagram involving the liquidus and solidus lines were computed self-consistently in the framework of the combined free energy of Flory-Huggins for liquid–liquid phase separation and phase field free energy for crystal solidification. The ternary phase diagram of PES/PVP/G blends was subsequently established that consisted of various coexistence regions. The actual amounts of genistein incorporated in the PES/PVP membranes were determined as a function of weight percent of genistein in feed. On the basis of UV-vis spectroscopy, the extent of genistein leaching during incubation in human blood was evaluated in conjunction with the PVP leaching from the blend membrane.     

A digital crystal-less clock generator using a phase error corrector

Microsystem Technologies - A multi-phase digital crystal-less clock generator (CLCG) with a phase error corrector is presented for on-chip and multi-phase systems. For the temperature variations,...     

Application of optical film with micro-lens array on a solar concentrator

A plastic solar concentrating optical film with horizontal cylinder micro-lens array (HCMA) is presented in this study. The solar concentrator (SC) is in the form of optical film with HCMA and it is attached on the surface of a solar cell. This film is a polymethylmethacrylate (PMMA)-based optical layer. Compared with a plain solar collecting optical film without HCMA, the solar collecting optical film with HCMA can reduce the opportunity of reflection as light arrives at the surface and therefore can increase the refraction coefficient. As a result, the gain of photovoltaic power can be improved with the SC. Light is efficiently refracted by the HCMA and absorbed by the solar cell without the need of a solar tracking mechanism. Optimization of geometrical parameters of HCMA such as contact angle and gap (interspace) between each horizontal cylinder micro-lens is designed by simulation. The procedures of fabrication include reflow process, nickel-cobalt (Ni-Co) electroplating, and molding process. The measurement equipment of NEWPORT Oriel 91160+MODEL 6285 is utilized to measure the parameters such as open-circuit voltage V_oc, short-circuit current I_sc, and fill factor F.F., relating to the efficiency of the complete system. The experimental results show that a gain of photovoltaic power of about 3.30% is obtained with a contact angle of 62° and a gap of 15 μm.     

Enhancing the electrocatalytic water splitting efficiency for amorphous MoSx

Amorphous molybdenum sulfide (MoS_x) materials have been considered as cheap and promising catalysts for hydrogen evolution reaction (HER). In this contribution, we report that the amorphous MoS_x catalysts prepared by the low temperature thermolysis of the (NH₄)₂MoS₄ precursors on carbon clothes (catalyst loading: 3.2 mg/cm²) exhibit a Tefal slope of 50.5 mV/dec and a high exchange current density of 1.5 × 10⁻³ mA/cm² in 0.5 M H₂SO₄ solutions. Spectroscopic studies of the amorphous MoS_x catalysts show that the increase of HER efficiency is positively correlated to the concentration of S₂²⁻ species, providing strong evidence to support the argument that S₂²⁻ is an active species for electrocatalytic HER. Additionally, the method for preparing catalysts is simple, scalable and applicable for large-scale production.