An object oriented/DEVS framework for strategic modelling and industry simulation

The use of simulation modelling for the development of business strategy models, at an industry level, focusing on the exploration of different scenarios and future policy, has been gaining increased acceptance and popularity over the last decade. This thesis develops a modelling and simulation framework for industry simulation, extending the approach of System Dynamics, by integrating recent concepts from software engineering and mathematical formalisms for discrete event system modelling. The current modelling view of industry simulation, based on System Dynamics, is reviewed. A critique of the capabilities of System Dynamics is presented, regarding the ability of the System Dynamics core technology to address the broad requirements of industry modelling. We focus the critique and develop a research agenda around the issues of natural model building, model structure and focus, model reusability and time representation. An overview of manufacturing simulation and the research directions in that area, is presented with the objective of identifying possible areas of cross-fertilization which can be used in modelling at the industry level in a more effective way. A review of Object Orientation is presented, along with a general review of mathematical formalisms for the description of discrete event systems, with particular focus on the Discrete Event System Specification formalism (DEVS) [Zeigler (1976, 1984)]. An innovative synthesis of Object Orientation and DEVS is proposed in order to address the research questions which resulted from our critique of System Dynamics. A Smalltalk implementation of the concepts supported by the synthesis, called OO/DEVS, has been developed. Using as a point of reference the requirements of industry simulation, we build upon a critique of previous DEVS implementations (placed within the manufacturing simulation problem domain), by presenting an innovative implementation view of DEVS, which exploits fully the concepts supported by Object Orientation. The issues related to graphical model specification within OO/DEVS, and its comparison to the modem System Dynamics graphical user interfaces, are explored. A OO/DEVS Graphical User Interface and its implementation are explored and presented. Two case studies have been employed, in order to test the capabilities of OO/DEVS as an alternative to System Dynamics, as well as to demonstrate the modelling characteristics of the framework and its implementation. A comparative study is presented, where a capacity investment model of the postprivatised UK Electricity Industry is developed in both frameworks. The model is used as a vehicle for assessing the modelling characteristics of OO/DEVS versus System Dynamics. Our initial conclusion is that the modelling properties of OO/DEVS can address at a sufficient level the research issues related to the System Dynamics core technology. Finally, a large scale modelling case study is carried out, within one of the UK Electricity Distribution companies, where a OO/DEVS model of the Electricity Markets is developed jointly with a management team. This real application establishes the value of OO/DEVS, and its modelling characteristics, as a powerful platform for building decision support industry models

Alkaline phophatase levels in Finnish hard cheeses and milk products

Alkaline phosphatase (ALP) is an endogenous enzyme found in milk, which is inactivated at higher temperatures than vegetative bacteria and is thus used as an indicator of a successful pasteurisation. The ability of ALP to reactivate allows it to be found in milk products that are claimed to be pasteurised. The aim of this Master‘s thesis was to understand the reactivation behaviour of ALP in order to ascertain whether high levels found in milk products are correlated to a normal reactivation property of the enzyme or other possible reasons, such as a failed pasteurisation or contamination. This work also aimed to define the mean ALP activities found in specific commercial milk products and their deviation from the acceptable levels. Another scope was to determine the freeze stability of ALP to define its appropriateness for post-stored analysis. Lastly, the examination of ALP location in milk fat membrane globules was examined to interpret the variation of enzyme activity levels in products of different fat content. The experimental part of the Master‘s thesis was divided into three parts. The first part included the record of ALP activities of different commercial Finnish milk products which are analysed in different groups according to their fat content and product type. The second part concentrated on the heat-treatment of milk samples at different time-temperature relationships and followed the reactivation behaviour of ALP. The total micro-flora was taken into consideration in order to observe any relation between the increased ALP activities and microbial growth. ALP activities were measured by a fluorimetric method, a quick three minute method which has the advantage of being more accurate compared to colourimetric methods. The third part examined the fraction in which ALP activities are found in milk after separation and its freeze stability when stored at -79 ºC. Commercial cheeses showed a high ALP activity in Emmental thermised cheeses and an activity less than 10 mU/g in other cheese types and pasteurised cheeses. In commercial milks, UHT treated and those closer to expiration date, high ALP activities were found, while pasteurised milks had low activities below the higher acceptable levels. The reactivation property of milk samples that were heat-treated in ALP was not related with the microbial growth and was quicker when the milk samples were heat-treated at higher temperatures. After the separation of cream from whole milk samples, ALP activity was found in the skim milk part. In conclusion, ALP activities did not decrease significantly following freeze storage for a few days showing its stable freeze properties

Wilson ratio of a Tomonaga-Luttinger liquid in a spin-1/2 Heisenberg ladder

Using micromechanical force magnetometry, we have measured the magnetization of the strong-leg spin-1/2 ladder compound (C$_7$H$_{10}$N)$_2$CuBr$_2$ at temperatures down to 45 mK. Low-temperature magnetic susceptibility as a function of field exhibits a maximum near the critical field H_c at which the magnon gap vanishes, as expected for a gapped one-dimensional antiferromagnet. Above H_c a clear minimum appears in the magnetization as a function of temperature as predicted by theory. In this field region, the susceptibility in conjunction with our specific heat data yields the Wilson ratio R_W. The result supports the relation R_W=4K, where K is the Tomonaga-Luttinger-liquid parameter

The True Seroprevalence of Enteropathogenic Yersinia in Pigs, a Hayesian Approach

Bayesian inference was used to estimate the true seroprevalence of enteropathogenic Yersinia in pigs in Finland. Sensitivity and specificity of the diagnostic test were also estimated. One-hundred-seventy-two pigs of different ages were sampled and analysed for antibodies against enteropathogenic Yersinia outer proteins by a commercially ELISA test

A comparative analysis of meat inspection data as an information source of the health and welfare of broiler chickens based on Finnish data

The comprehensive, reliable, and comparable meat inspection (MI) data of broiler chickens (i.e. broilers) are essential for the monitoring and surveillance of broiler health and welfare at the national and European Union (EU) levels. We compared the condemnation causes issued to broiler carcasses during MI in four large Finnish broiler slaughterhouses (SHs) by investigating the similarities and differences between local MI instructions used in the SHs. The way in which MI condemnations were recorded in the Finnish Food Authority's (FFA's) MI statistics were also explored. We additionally analysed the FFA's official MI data from the 2015-2019 period. The study showed that the MI criteria used in the SHs differed from one another regarding how severe or extensive a broiler defect or disease must be to cause condemnation during MI. In Finland, the annual total condemnation prevalence of whole broilers varied between 2.6% and 4.8% in 2015-2019, and a significant difference was observed between the SHs' monthly total condemnation prevalences, except in two SH pairs. Mistakes in recording the FFA's MI statistics and differences in the SH operators' reasons to reject broilers from the food chain affect the comparability of the condemnation prevalences between the SHs. Only half of the SHs partially condemned broiler carcasses and collected data concerning these condemnations. Cellulitis (0.3-1.0%), ascites (0.3-0.4%), and body cavity disorders (0.2-0.3%) were the most common causes for condemning whole broiler carcasses in 2015-2019. The MI data can be used for monitoring and surveillance purposes only once the differences between the SH data and data reliability are known. Although the harmonization of all condemnation causes is impossible, harmonizing the condemnations of carcasses with diseases that most threaten broiler health and welfare and cause the largest economic losses would be important.Peer reviewe

Identification of Yersinia at the Species and Subspecies Levels Is Challenging

Peer reviewe

Two copies of the ail gene found in Yersinia enterocolitica and Yersinia kristensenii

Yersinia enterocolitica is the most common Yersinia species causing foodborne infections in humans. Pathogenic strains carry the chromosomal ail gene, which is essential for bacterial attachment to and invasion into host cells and for serum resistance. This gene is commonly amplified in several PCR assays detecting pathogenic Y. enterocolitica in food samples and discriminating pathogenic isolates from non-pathogenic ones. We have isolated several non-pathogenic ail-positive Yersinia strains from various sources in Finland. For this study, we selected 16 ail-positive Yersinia strains, which were phenotypically and genotypically characterised. Eleven strains were confirmed to belong to Y. enterocolitica and five strains to Yersinia kristensenii using whole-genome alignment, Parsnp and the SNP phylogenetic tree. All Y. enterocolitica strains belonged to non-pathogenic biotype 1A. We found two copies of the ail gene (ail1 and ail2) in all five Y. kristensenii strains and in one Y. enterocolitica biotype 1A strain. All 16 Yersinia strains carried the ail1 gene consisting of three different sequence patterns (A6-A8), which were highly similar with the ail gene found in high-pathogenic Y. enterocolitica biotype 1B strains (A2). The Ail protein encoded by the ail1 gene was highly conserved compared to the Ail protein encoded by the ail2 gene. Multiple sequence alignment of the ail gene and Ail protein were conducted with MAFF. In total, 10 ail sequence variations have been identified, of which 8 conserved ones belonged to the ail1 gene. According to our results, the detection of ail alone is not sufficient to predict the pathogenicity of Yersinia isolates.Peer reviewe

Prerequisites of inspection conditions for uniform post-mortem inspection in broiler chicken slaughterhouses in Finland

Meat inspection of broiler chickens (broiler) in the European Union is regulated by common legislation to secure meat safety. However, the legislation is general in nature and proper post-mortem inspection (PMI) of every carcass and visceral organs of broilers is challenging in slaughterhouses (SHs) with a high slaughter line speed. The aim of this study was to investigate the on-site organization and possible differences of the PMI in four Finnish SHs, which slaughter over 99% of broilers in Finland. Our results show that the meat inspector's available inspection time per broiler in the PMI varied between 0.28 and 0.90 s, with the shortest available inspection time in the SH with the highest slaughter line speed and the longest available inspection time in the SH with the slowest line speed. We observed that only part of the total inspection time per broiler could be used for true PMI in most (3/4) SHs, as the meat inspectors also performed other tasks during the PMI. We observed deficiencies in the visual inspection of broiler carcasses; in particular, the proper inspection of all or most of the body cavities was impossible in all SHs during the PMI. Some deficiencies in facilities (e.g. in recording system) were observed. Moreover, lighting properties varied between the SHs and a significant difference between illumination conditions at the first inspection stations in the SHs was observed. This study considered the prerequisites for proper PMI and revealed that the PMI of broilers was not completely uniform in Finland. The results emphasize the need for more precise guidelines and recommendations, especially for inspection time and lighting at inspection stations.Peer reviewe