The KB paradigm and its application to interactive configuration

The knowledge base paradigm aims to express domain knowledge in a rich formal language, and to use this domain knowledge as a knowledge base to solve various problems and tasks that arise in the domain by applying multiple forms of inference. As such, the paradigm applies a strict separation of concerns between information and problem solving. In this paper, we analyze the principles and feasibility of the knowledge base paradigm in the context of an important class of applications: interactive configuration problems. In interactive configuration problems, a configuration of interrelated objects under constraints is searched, where the system assists the user in reaching an intended configuration. It is widely recognized in industry that good software solutions for these problems are very difficult to develop. We investigate such problems from the perspective of the KB paradigm. We show that multiple functionalities in this domain can be achieved by applying different forms of logical inferences on a formal specification of the configuration domain. We report on a proof of concept of this approach in a real-life application with a banking company. To appear in Theory and Practice of Logic Programming (TPLP).Comment: To appear in Theory and Practice of Logic Programming (TPLP

ConfigNow: A knowledge based approach to configuration software

ConfigNow is package that allows users to create configuration software following a knowledge based approach. The user can write the constraints on the domain down in a separate file, using (extensions of) first order logic as knowledge representation language. The ConfigNow package then provides an interface to perform a number of tasks that one typically wants to solve in configuration software, and link this to the user interface.status: publishe

Detailed Analysis of the Microbial Population in Malaysian Spontaneous Cocoa Pulp Fermentations Reveals a Core and Variable Microbiota

The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial processes in today's food industry. The microbiota involved in cocoa pulp fermentations is complex and variable, which leads to inconsistent production efficiency and cocoa quality. Despite intensive research in the field, a detailed and comprehensive analysis of the microbiota is still lacking, especially for the expanding Asian production region. Here, we report a large-scale, comprehensive analysis of four spontaneous Malaysian cocoa pulp fermentations across two time points in the harvest season and two fermentation methods. Our results show that the cocoa microbiota consists of a "core" and a "variable" part. The bacterial populations show a remarkable consistency, with only two dominant species, Lactobacillus fermentum and Acetobacter pasteurianus. The fungal diversity is much larger, with four dominant species occurring in all fermentations ("core" yeasts), and a large number of yeasts that only occur in lower numbers and specific fermentations ("variable" yeasts). Despite this diversity, a clear pattern emerges, with early dominance of apiculate yeasts and late dominance of Saccharomyces cerevisiae. Our results provide new insights into the microbial diversity in Malaysian cocoa pulp fermentations and pave the way for the selection of starter cultures to increase efficiency and consistency.status: publishe

Detailed Analysis of the Microbial Population in Malaysian Spontaneous Cocoa Pulp Fermentations Reveals a Core and Variable Microbiota

<div><p>The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial processes in today's food industry. The microbiota involved in cocoa pulp fermentations is complex and variable, which leads to inconsistent production efficiency and cocoa quality. Despite intensive research in the field, a detailed and comprehensive analysis of the microbiota is still lacking, especially for the expanding Asian production region. Here, we report a large-scale, comprehensive analysis of four spontaneous Malaysian cocoa pulp fermentations across two time points in the harvest season and two fermentation methods. Our results show that the cocoa microbiota consists of a “core” and a “variable” part. The bacterial populations show a remarkable consistency, with only two dominant species, <i>Lactobacillus fermentum</i> and <i>Acetobacter pasteurianus</i>. The fungal diversity is much larger, with four dominant species occurring in all fermentations (“core” yeasts), and a large number of yeasts that only occur in lower numbers and specific fermentations (“variable” yeasts). Despite this diversity, a clear pattern emerges, with early dominance of apiculate yeasts and late dominance of <i>Saccharomyces cerevisiae</i>. Our results provide new insights into the microbial diversity in Malaysian cocoa pulp fermentations and pave the way for the selection of starter cultures to increase efficiency and consistency.</p></div

Overview of all detected lactic acid and acetic acid bacterial species in the different spontaneous fermentations.

<p>*B1 and H1 (box and heap fermentation 1 respectively) were performed in the beginning of the harvest season (October 2011), while B2 and H2 (box and heap fermentation 2 respectively) were executed at the end of the harvest season (January 2012).</p><p>LAB = lactic acid bacteria, AAB = acetic acid bacteria.</p

Yeast diversity in four Malaysian spontaneous cocoa pulp fermentations.

<p>Box fermentation 1 (B1, October 2011), heap fermentation 1 (H1, October 2011), box fermentation 2 (B2, January 2012) and heap fermentation 2 (H2, January 2012). In total, 769 yeast isolates were identified, allowing an in-depth analysis of the yeast diversity. Yeast species are ordered according to the frequency by which they were isolated from the different fermentation samples. The upper eight species were found in at least three fermentations, while the other species were only found in two or less fermentations. When the yeast counts were above the detection limit, different colors represent the relative population size of a certain species at a certain time point (dark blue : <5%, light blue : 5–10%, dark yellow : 10–50%, yellow : 50–100%). Hollow squares indicate that the yeast species was detected when the yeast cell count had dropped below the detection limit.</p

Microbial cell counts during four Malaysian spontaneous cocoa pulp fermentations.

<p>A: yeast. B: lactic acid bacteria (LAB). C: acetic acid bacteria (AAB). Box fermentation 1 (October 2011, black), heap fermentation 1 (October 2011, grey), box fermentation 2 (January 2012, brown) and heap fermentation 2 (January 2012, orange). The dashed arrows indicate when the cell counts rise up to or drop below the detection limit [1.5 10⁴ colony forming units (CFU) g⁻¹]. Solid arrows indicate turning.</p

Temperature and pH of cocoa pulp in four Malaysian spontaneous cocoa pulp fermentations.

<p>*B1 and H1 (box and heap fermentation 1 respectively) were performed in the beginning of the harvest season (October 2011), while B2 and H2 (box and heap fermentation 2 respectively) were executed at the end of the harvest season (January 2012).</p><p>Different parameters are listed for each fermentation: pH_i = initial pH, pH_f = final pH, pH_min = minimal pH, pH_max = maximal pH, T_i = initial temperature, T_f = final temperature, T_min = minimal T, T_max =  maximal temperature.</p

Yeast population dynamics in four Malaysian spontaneous cocoa pulp fermentations.

<p>Box fermentation 1 (B1, October 2011), heap fermentation 1 (H1, October 2011), box fermentation 2 (B2, January 2012) and heap fermentation 2 (H2, January 2012). Total yeast count (left axis) is indicated as a black thick line (top of the graph). Temperature (right axis) is indicated as a dashed black line. The dashed arrows indicate when the yeast cell count rises to or drops below the detection limit [1.5 10⁴ colony forming units (CFU) g⁻¹]. Only the four “core” yeast species are shown independently. The relative contribution of a yeast species (indicated by the colors) to the population at a certain time point is represented as the fraction (%) of the total yeast count. Note that the scale for the total yeast count (left) is logarithmic, whereas the relative fraction of each yeast species in the population is presented as fraction of the total population and thus represented on a linear scale. Solid arrows indicate turning. The second turning (96 h) of B2 and H2 is not shown.</p