Computing budget allocation rules for multi-objective simulation models based on different measures of selection quality

In an optimal computing budget allocation problem, different measures of selection quality determine how the best set of designs can be identified and how the simulation budget should be allocated among the designs. In this paper, we look at several measures of selection quality and derive respective allocation rules for the multi-objective computing budget allocation problem. Some computational experiments are carried out to compare the performance of the allocation rules and to identify the suitable ones in certain scenarios.     

BELONGING AND TIME: Technology,Heidegger's ‘Events of Appropriation,’ and New Dutch Architecture

There are two trends in the way contemporary cities deal with technology. The first is a conceited mobilising of resistance to modernisation in the hope of arresting the consequences of technologisation such as rampant development, suburban sprawl, congestion, dominance of vehicular infrastructure and compromised amenities. Amsterdam. Copenhagen, outer Paris, London, Buenos Aires, and a host of American cities including Houston fall into this category. The second trend is a headlong plunge into technology in which cities like Beijing, Seoul, Kuala Lumpur, and Bangkok multiply new urban accommodation with immense demographic and infrastructural acceleration. The use of technology is brazen, and the speed of construction elides any architectural pretensions. Densities achieved in these cities are far higher than in their Continental European counterparts, pointing to the obsolescence of Western town planning and urban design.     

In-situ growth of CdS quantum dots on g-C3N4 nanosheets for highly efficient photocatalytic hydrogen generation under visible light irradiation

Well dispersed CdS quantum dots were successfully grown in-situ on g-C₃N₄ nanosheets through a solvothermal method involving dimethyl sulfoxide. The resultant CdS–C₃N₄ nanocomposites exhibit remarkably higher efficiency for photocatalytic hydrogen evolution under visible light irradiation as compared to pure g-C₃N₄. The optimal composite with 12 wt% CdS showed a hydrogen evolution rate of 4.494 mmol h⁻¹ g⁻¹, which is more than 115 times higher than that of pure g-C₃N₄. The enhanced photocatalytic activity induced by the in-situ grown CdS quantum dots is attributed to the interfacial transfer of photogenerated electrons and holes between g-C₃N₄ and CdS, which leads to effective charge separation on both parts.     

Bicycle crash casualties in a highly motorized city

The characteristics of bicycle crashes in cities where bicycles are a minor transport mode have received little attention in road safety research. However, the characteristics of these injury-inflicting bicycle crashes are expected to be very different from those happening in cities where cycling is generally considered as one of the major transport modes. Specifically, this study has the following three objectives: (1) to conduct the first scientific spatial analysis of bicycle crashes in Hong Kong; (2) to analyze the circumstances leading to bicycle crashes; and (3) to conduct an epidemiological study on injury patterns of cyclist casualties. Various spatial and statistical tools, including buffer analysis, chi-square tests, analysis-of-variance and binary logistic regression, are used to analyze the bicycle crashes in Hong Kong from 2005-2007. An important finding of this paper is that the bicycle safety problem has a clear spatial dimension. The crash circumstances in different parts of the city differed systematically. Furthermore, the findings suggest that initiatives to develop new cycle tracks and to encourage bicycles as a transport mode must be planned carefully with new infrastructure and policies to ensure the safety of cyclists.     

A study on crate sizing problems

This paper studies the crate sizing problem to predetermine optimal standard packaging crate sizes for a demand of assorted sizes of products to minimise space and costs. The crate sizing problem is a real world logistics scenario faced by an existing multinational corporation in the applied chemistry industry. Customer demands come in a mix of rolls to be packaged in individual crates and then shipped in shipping containers from plants to customers. Firstly, a linear crate length optimisation model is introduced with the objective to minimise the total loss of extra space inside the crates for a given distribution of customer demands. In order to take inventory costs of crates into consideration, a second problem is introduced to both find the optimal number of crate types and the corresponding lengths such that the total costs of packaging and inventory are minimised. The latter problem is first formulated as a non-linear optimisation model and then solved using dynamic programming approach to balance the trade-off between the number of crate types and the penalty cost for space wastage inside the crates.     

Flexible space-sharing strategy for storage yard management in a transshipment hub port

In this paper, a storage yard planning problem is studied for a transshipment port with limited space and high-throughput level. Generally, the consignment strategy is used in the yard for a transshipment port, where containers to the same destination vessel are stored together. This is to facilitate faster loading process as it reduces reshuffles as well as long distance movements of yard cranes. However, the consignment strategy is known to be inefficient in space utilization since each storage location must be dedicated to a particular vessel. To improve the space utilization while retaining the advantage of consignment, a new approach named the “flexible space-sharing strategy” is proposed. The idea is that the container space can be shared by two different vessels as long as their containers do not occupy the space at the same time. This strategy allows the same storage location to be reserved for two vessels. The amount of space will only be allocated to a specific vessel on the arrival of corresponding containers. By controlling where to stack the containers in the storage locations, the containers to each vessel are not mixed and the consignment feature can be preserved. This strategy is first formulated as a mixed integer program (MIP). As the MIP model has a block diagonal structure, we develop a search algorithm which combines MIP and heuristics to find the solution. The numerical experiments show that the “flexible space-sharing strategy” can handle much more containers within the same storage space compared with the “non-sharing strategy”.     

Screening of commercial and pecan shell-extracted liquid smoke agents as natural antimicrobials against foodborne pathogens

Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli . The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed significant differences between their inhibitory concentrations depending on the type of solvent used for extraction. The results indicated that the liquid smoke samples tested in this study could serve as effective natural antimicrobials and that their inhibitory effects depended more on the solvents used for extraction than the wood source.     

Impedimetric immunoglobulin G immunosensor based on chemically modified graphenes

Immunosensors which display high sensitivity and selectivity are of utmost importance to the biomedical field. Graphene is a material which has immense potential for the fabrication of immunosensors. For the first time, we evaluate the immunosensing capabilities of various graphene surfaces in this work. We propose a simple and label-free electrochemical impedimetric immunosensor for immunoglobulin G (IgG) based on chemically modified graphene (CMG) surfaces such as graphite oxide, graphene oxide, thermally reduced graphene oxide and electrochemically reduced graphene oxide. Disposable electrochemical printed electrodes were first modified with CMG materials before anti-immunoglobulin G (anti-IgG), which is specific to IgG, was immobilized. The principle of detection lies in the changes in impedance spectra of the redox probe after the attachment of IgG to the immobilized anti-IgG. It was found that thermally reduced graphene oxide has the best performance when compared to the other CMG materials. In addition, the optimal concentration of anti-IgG to be deposited onto the modified electrode surface is 10 μg ml(-1) and the linear range of detection of the immunosensor is from 0.3 μg ml(-1) to 7 μg ml(-1). Finally, the fabricated immunosensor also displays selectivity for IgG.