Dynamic allocation of resources to virtual path agents

One of the major problems faced in operating large networks is the enormous amount of processing and communications overhead required for setting up and tearing down the large number of connections maintained by the network. ATM and MPLS aim at solving these problems via the Virtual Path (VP) mechanism which is used to group together the connections. When a need for setting up a connection rises, the request and its resource allocation are processed by the VP agent and not by the network, thus reducing the processing cost significantly. An important question in the design of these networks is the amount of network resources to be dynamically allocated to and held by the VP agents; too high allocation will result with bandwidth resource waste, while too low allocation will result with heavy connection set-up and tear-down processing load. In this paper we deal with this problem, and at deriving simple operational rules to determine the amount of bandwidth resources to be held by the various VP agents, while balancing between bandwidth waste and connection processing overhead. We formulate the resource allocation problem by accounting both for bandwidth utilization and for connection processing constraints. Recognizing the complexity of the problem, we use a decomposition approach in which we first analyze the single link problem and then propose to use this solution as a building block in constructing algorithms for the whole network. For the single link problem we realize that the pure problem is too complex and thus formulate an approximate model and derive the optimal allocation for it. The optimal rule is expressed as a closed-form square-root allocation. Extensive numerical examination shows that the rule proposed yields very efficient allocations. For the full network problem, we propose to capitalize on the closed form structure of the single link problem solution and use it in devising algorithms for the whole network.     

Single crystalline CdTe solar cells grown by MOCVD

CdTe has unique advantages for space applications solar cells. Previous structures were not able to yield the full potential of single crystalline solar cells. The limitations of these structures are discussed. We then report a new structure that is being studied with numerical simulations and preliminary experimental results. The actual fabrication and characterization of the cells under study are discussed in detail.     

A branch-and-bound algorithm for the concave cost supply problem

Effective supplier selection and allocation of order quantity among multiple suppliers are indispensable to the success of a manufacturing company. While companies have begun to turn into a comprehensive multi-criteria approach, most buyers still consider purchasing cost to be their primary concern in selecting their suppliers. In this paper, we consider the concave cost supply problem where a manufacturer seeks to select the suppliers and simultaneously procure the quantity of material/component required for production at the minimum total cost during a standard production period. We provide and validate an effective and efficient branch-and-bound algorithm that is finite and that finds the global optimal solution of the problem without any restrictions on the cost functions or on the set of input parameters used in the problem. Numerical experiments are conducted to evaluate the performance of the proposed algorithm.     

Synthesis and characterization of 2‐hydroxyethylmethacrylate/2‐(3‐indol‐yl)ethylmethacrylamide‐based novel hydrogels as drug carrier with in vitro antibacterial properties

In this study, a new cationic monomer 2‐(3‐indol‐yl)ethylmethacrylamide (IEMA) derived from tryptamine was synthesized in a single step and characterized by Fourier transform infrared (FTIR), ¹H‐NMR, and ¹³C‐NMR. Then, one‐step preparation of novel poly[2‐hydroxyethylmethacrylate‐c‐2‐(3‐indol‐yl)ethylmethacrylamide], or p(HEMA‐c‐IEMA), copolymeric hydrogels has been performed successfully with IEMA and 2‐hydroxyethylmethacrylate (HEMA) as monomers using free radical aqueous polymerization. The hydrogels were characterized with scanning electron microscopy, FTIR, elemental analysis, thermogravimetric analysis, and texture profile analysis instruments. p(HEMA‐c‐IEMA) hydrogels were used for swelling, diffusion, drug release, and antibacterial activity studies. The drug‐release behavior of the hydrogels was determined as a function of time at 37 °C in pH 1.2 and 7.2. The swelling and drug‐release studies showed that an increased IEMA amount caused a higher increase in swelling and drug‐release values. Additionally, zero‐order, first‐order, and Higuchi equation kinetic models were applied to the drug‐release data, and the data fit well in the Higuchi model, and the Peppas power‐law model was applied to the release mechanism. Finally, the antibacterial activities of the hydrogels were screened against Gram‐positive bacteria (Bacillus cereus and Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli and Salmonella typhimurium). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45550.     

Photocatalytic and Photoelectrocatalytic Performance of 1% Pt Doped TiO2 for the Detoxification of Water

The degradation of formic acid (HCOOH), FA (a surrogate contaminant) using titanium dioxide (TiO₂) and 1% Pt doped TiO₂ electrodes, prepared by sol—gel methods, was investigated in a photoelectrocatalytic (PEC) system in order to determine the effect of Pt doping on the oxidation potential of TiO₂. Pt doping shifts the position of band edge and therefore the direct and indirect oxidation potentials of TiO₂ in PEC systems. As a result, the degradation of formic acid via the generation of hydrogen peroxide production on 1%Pt—TiO₂ electrodes was much better than that on non-doped electrodes. The degradation of HCOOH was also examined with respect to the faradaic efficiency of this process. It was found that the 1%Pt—TiO₂ photoanode had a 30% higher efficiency than that of non-doped TiO₂ photoanodes.     

Fault detection on robot manipulators using artificial neural networks

Nowadays, gas welding applications on vehicle’s parts with robot manipulators have increased in automobile industry. Therefore, the speed of end-effectors of robot manipulator is affected on each joint during the welding process with complex trajectory. For that reason, it is necessary to analyze the noise and vibration of robot’s joints for predicting faults. This paper presents an experimental investigation on a robot manipulator, using neural network for analyzing the vibration condition on joints. Firstly, robot manipulator’s joints are tested with prescribed of trajectory end-effectors for the different joints speeds. Furthermore, noise and vibration of each joint are measured. And then, the related parameters are tested with neural network predictor to predict servicing period. In order to find robust and adaptive neural network structure, two types of neural predictors are employed in this investigation. The results of two approaches improved that an RBNN type can be employed to predict the vibrations on industrial robots.     

敏捷制造模式中检验信息的IDEFO模型研究

为在敏捷制造中实现检验的自动化,分析敏捷制造中公差和表面质量的检验信息的需求,提出检验信息模型的功能,设计和开发了检验信息模型的IDEF0（Integration　Definition　for　Function　Modelling）模型。     

Modeling the order picking function in supply chain systems: formulation, experimentation, and insights

Order picking is found at the interface of production and distribution networks within supply chain systems. In this study the order picking function is modeled to explore its role with respect to inventory deployment and centralized distribution planning, in the presence of production economies of scale and deterministic demand. The results of 5400 numerical experiments suggest that, for certain system cost structures, there may exist an inherent tension between commercially independent stages, owed to the consequences of decentralized planning. Increasing total system cost due to pull style planning over centralized planning appeared to be most heavily influenced by the proportion of costs shared by various system stages around the order picker, and this gap averaged over 30% in worst-case scenarios.