A tutorial on multiobjective optimization: fundamentals and evolutionary methods

In almost no other field of computer science, the idea of using bio-inspired search paradigms has been so useful as in solving multiobjective optimization problems. The idea of using a population of search agents that collectively approximate the Pareto front resonates well with processes in natural evolution, immune systems, and swarm intelligence. Methods such as NSGA-II, SPEA2, SMS-EMOA, MOPSO, and MOEA/D became standard solvers when it comes to solving multiobjective optimization problems. This tutorial will review some of the most important fundamentals in multiobjective optimization and then introduce representative algorithms, illustrate their working principles, and discuss their application scope. In addition, the tutorial will discuss statistical performance assessment. Finally, it highlights recent important trends and closely related research fields. The tutorial is intended for readers, who want to acquire basic knowledge on the mathematical foundations of multiobjective optimization and state-of-the-art methods in evolutionary multiobjective optimization. The aim is to provide a starting point for researching in this active area, and it should also help the advanced reader to identify open research topics.     

Coupling the multizone airflow and contaminant transport software CONTAM with EnergyPlus using co-simulation

Building modelers need simulation tools capable of simultaneously considering building energy use, airflow and indoor air quality (IAQ) to design and evaluate the ability of buildings and their systems to meet today’s demanding energy efficiency and IAQ performance requirements. CONTAM is a widely-used multizone building airflow and contaminant transport simulation tool that requires indoor temperatures as input values. EnergyPlus is a prominent whole-building energy simulation program capable of performing heat transfer calculations that require interzone and infiltration airflows as input values. On their own, each tool is limited in its ability to account for thermal processes upon which building airflow may be significantly dependent and vice versa. This paper describes the initial phase of coupling of CONTAM with EnergyPlus to capture the interdependencies between airflow and heat transfer using co-simulation that allows for sharing of data between independently executing simulation tools. The coupling is accomplished based on the Functional Mock-up Interface (FMI) for Co-simulation specification that provides for integration between independently developed tools. A three-zone combined heat transfer/airflow analytical BESTEST case was simulated to verify the co-simulation is functioning as expected, and an investigation of a two-zone, natural ventilation case designed to challenge the coupled thermal/airflow solution methods was performed.     

Bestimmung der Verteilung von Substituenten in den Körnern von Stärkederivaten

Determination and Distribution of Substituents in the Granules of Starch Derivatives . Distribution of substituents in phosphate and citrate potato starch was determined by means of scanning electron microscopy and X-ray microanalysis. With both derivatives an even homogenous derivatisation all over the granule was noticed.     

Physicochemical and antioxidative properties of red and black rice varieties from Thailand,China and Sri Lanka

Nine red and three black rice varieties from Thailand, China and Sri Lanka were analysed to determine their proximate composition and their physicochemical and antioxidant properties. Four groups of rice varieties with different amylose contents were identified. Cyanidin 3-glucoside and peonoidin 3-glucoside were confirmed as the dominant anthocyanins in black rice varieties with contents ranging from 19.4 to 140.8 mg/100 g DM and 11.1–12.8 mg/100 g DM, respectively. Total phenolic content (TPC) differed significantly between the varieties, but not between the colours. Highest TPC was found in the red Thai rice Bahng Gawk (BG) with 691 FA equivalent mg/100 g DM, which showed as well the highest antioxidant properties. In red varieties, the major phenolic acids in the free form were ferulic, protocatechuic and vanillic acid, whereas in black varieties protocatechuic acid was dominant followed by vanillic and ferulic acid. In the bound form, ferulic acid was predominant in both colours, where contents differed significantly, followed by p-coumaric and vanillic acid. The antioxidative capacity did not differ significantly between both colours but amongst genotypes. Antioxidant capacity of rice varieties ranged within 0.9–8.1 mmol Fe(II)/100 g DM for FRAP and 2.1–12.3 mmol TEAC/100 g DM. DPPH scavenging ability ranged from 13.0% to 76.4% remaining DPPH.     

Herstellung von Stärkederivaten durch Heißextrusion

Production of Starch Derivatives by Cooking Extrusion. It was possible to produce starch derivatives from corn and potato starches and maize grit by cooking extrusion process with a conical, counter-rotating twin-screw extruder. The used chemical reagents for derivatization were citric acid for citrate-starches, sodium trimetaphosphate for phosphate-starches and 2,3-epoxypropyl-trimethyl-ammonium chloride and 3-chloro-2-hydroxypropyl-trimethyl-ammonium chloride for cationic starches. With citrate starches 60–70% of bound citric acid yields were found in the extrudates. Heat treatment of extrudates after extrusion increased the amount of bound citric acid to 68–77% and icreased Brabender-viscosity values. Shear stability and freeze-thaw stability were also improved. For phosphate starches 15–30% of bound phosphate were found in the extrudates. After heat treatment bound phosphate was increased to 20–35%. Physical and functional properties were also improved. The production of cationic starches by cooking extrusion process was also possible. There was about 50–60% of bound nitrogen from reagents in the extrudates. This yield was further increased to 65–90% after heat treatment.     

Untersuchung gefriergetrockneter Stärkekleister und Stärkeschwämme im Rasterelektronenmikroskop

Examination of Freeze-Dried Starch Pastes and Starch Sponges by Means of Scanning Electron Microscope. Pastes of potato and corn starch as well as various starch derivatives were examined by means of scanning electron microscope (SEM). As preparation method freeze fixation followed by freeze-drying were used. Special attention was directed to changes occuring in pastes after slow freezing and defrosting. Sample preparation which is more complex for the SEM than for light microscope has the advantage of its picture giving more accurate information on paste structure than those obtained by light microscopy. On the one hand, tests confirm results obtained by other authors on the structure of starch pastes by means of light microscopic photography, furthermore, new information was gathered especially regarding non-frozen pastes and pastes of starch derivatives. Illustrations of starch sponges as obtained by means of SEM are far more expressive than those obtained by conventional methods.     

Characterizing gaseous air cleaner performance in the field

As part of an ongoing effort to better understand the performance of indoor air cleaners in buildings, the National Institute of Standards and Technology (NIST) has completed a series of gaseous air cleaner field tests and model simulations. This paper focuses on experiments to measure the removal of decane with a sorption-based in-duct gaseous air cleaner and a sorption-based portable air cleaner in a single-zone test house. Due to the lack of standardized gaseous air cleaner field testing protocols, a field test method was developed using semi-real-time concentration measurements and mass balance analysis. A total of 24 experiments were completed with directly measured single-pass removal efficiencies ranging from 24% to 56% and removal efficiencies based on a transient whole building mass balance ranging from 30% to 44%. Experimental results revealed important factors affecting field performance such as air cleaner contaminant loading for the in-duct air cleaner and room air mixing for the portable air cleaner. An additional six tests were conducted to evaluate the predictive capability of the indoor air quality model CONTAM.