Analysis and Application of Advanced Control Strategies to a Heating Element Nonlinear Model

open4siSustainable control has begun to stimulate research and development in a wide range of industrial communities particularly for systems that demand a high degree of reliability and availability (sustainability) and at the same time characterised by expensive and/or safety critical maintenance work. For heating systems such as HVAC plants, clear conflict exists between ensuring a high degree of availability and reducing costly maintenance times. HVAC systems have highly non-linear dynamics and a stochastic and uncontrollable driving force as input in the form of intake air speed, presenting an interesting challenge for modern control methods. Suitable control methods can provide sustainable maximisation of energy conversion efficiency over wider than normally expected air speeds and temperatures, whilst also giving a degree of “tolerance” to certain faults, providing an important impact on maintenance scheduling, e.g. by capturing the effects of some system faults before they become serious.This paper presents the design of different control strategies applied to a heating element nonlinear model. The description of this heating element was obtained exploiting a data driven and physically meaningful nonlinear continuous time model, which represents a test bed used in passive air conditioning for sustainable housing applications. This model has low complexity while achieving high simulation performance. The physical meaningfulness of the model provides an enhanced insight into the performance and functionality of the system. In return, this information can be used during the system simulation and improved model based and data driven control designs for tight temperature regulation. The main purpose of this study is thus to give several examples of viable and practical designs of control schemes with application to this heating element model. Moreover, extensive simulations and Monte Carlo analysis are the tools for assessing experimentally the main features of the proposed control schemes, in the presence of modelling and measurement errors. These developed control methods are also compared in order to evaluate advantages and drawbacks of the considered solutions. Finally, the exploited simulation tools can serve to highlight the potential application of the proposed control strategies to real air conditioning systems.openTurhan, T.; Simani, S.; Zajic, I.; Gokcen Akkurt, G.Turhan, T.; Simani, Silvio; Zajic, I.; Gokcen Akkurt, G

Determination of lactic acid bacteria in Kaºar cheese and identification by Fourier transform infrared (FTIR) spectroscopy

Lactic acid bacteria (LAB) arise in Kaşar cheese, an artisanal pasta filata cheese produced in Turkey from raw milk without starter addition or pasteurized milk  with starter culture. In this study, 13 samples of Kaşar cheese that were produced from raw milk were used as reference materials. LAB were characterized by using phenotypic, API and Fourier transform infrared (FTIR) spectroscopy methods. One hundred and fifty-seven (157) strains were isolated from 13 cheese  samples, and identification test was performed for 83 strains. At the end of the study, a total of 22 Lactococcus sp., 36 Enterecoccus sp. and 25 Lactobacillus sp. were determined in the isolated strains by phenotypic identification. After identification with FTIR spectroscopy and statistical analysis, expected results were not taken by FTIR spectroscopy due to higher correlation (> % 99) obtained with more than one reference culture. Fewer number of reference strains was a limitation of the analysis. Therefore, identification should be made with more reference bacteria in the FTIR analysis and should also be supported with molecular techniques.Key words: Kaşar cheese, lactic acid bacteria, identification, Fourier Transform Infrared (FTIR)

Effect of Time-pressure on Perceived and Actual Performance in Functional Software Testing

Background: Time-pressure is an inevitable reality of software industry that influences the performance of software engineers. It may result in adverse effects on software quality or distort the perception of performance on executed tasks to differ from actual performance. Objective: We aim to investigate the effect of timepressure on perceived and actual performance of software testers in the context of functional software testing. Method: We performed two controlled experiments with 87 graduate students in two academic terms. We assessed actual performance in terms of coverage (i.e. percentage of test cases correctly identified) and perceived performance using NASA-TLX. We have an independent factorial design for our experimental study. Results: The results reveal a significant effect of time-pressure on actual performance. However, we could not observe a significant effect of time-pressure on the perceived performance of the participants for the task undertaken. We also observed a significant negative correlation between actual and perceived performance when controlled for time-pressure and experimental session factors. Conclusion: Time-pressure affects the actual performance in a testing task but the perception of accomplishment by the testers is sustained irrespective of time-pressure, indicating an over-estimation issue. Perception of performance should be adjusted to align with reality to account for the effect of time pressure. This will lead to better self estimates of performance.Academy of Finland Projec

Lessons learned from a partial replication of an experiment in the context of a software engineering course

Replications are an integral component of experimentation through which the validity and reliability of the observed outcome in a previous experiment can be probed. In a strict replication, the experiment is executed in the same conditions as the original by following the same protocol and thus the evidence is strengthened statistically by means of increased sample size. Another objective for running replications is generalizing the experimental results beyond the limitations of one study and its context. For this purpose, certain elements of the original experiment, such as experimenters, experimental objects, and construct operationalization are altered and their impact is investigated. This paper presents lessons learned from a replication that was conducted as a part of an undergraduate university course in Serbia. The focus of the experiment was investigating the effectiveness of writing tests during the development process. The original experiment investigated the effectiveness of test-first programming and was conducted in Italy (Politecnico di Torino) with thirdyear computer science students during an intensive Java course. Lessons learned from this partial replication are that the given task descriptions and structure has an impact on the experiment outcome and that variations in metrics collection can occur when multiple researchers analyse the data, which requires metrics consolidation

Software defect prediction: do different classifiers find the same defects?

Open Access: This article is distributed under the terms of the Creative Commons Attribution 4.0 International License CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.During the last 10 years, hundreds of different defect prediction models have been published. The performance of the classifiers used in these models is reported to be similar with models rarely performing above the predictive performance ceiling of about 80% recall. We investigate the individual defects that four classifiers predict and analyse the level of prediction uncertainty produced by these classifiers. We perform a sensitivity analysis to compare the performance of Random Forest, Naïve Bayes, RPart and SVM classifiers when predicting defects in NASA, open source and commercial datasets. The defect predictions that each classifier makes is captured in a confusion matrix and the prediction uncertainty of each classifier is compared. Despite similar predictive performance values for these four classifiers, each detects different sets of defects. Some classifiers are more consistent in predicting defects than others. Our results confirm that a unique subset of defects can be detected by specific classifiers. However, while some classifiers are consistent in the predictions they make, other classifiers vary in their predictions. Given our results, we conclude that classifier ensembles with decision-making strategies not based on majority voting are likely to perform best in defect prediction.Peer reviewedFinal Published versio

İzmir‐Ankara suture as a Triassic to Cretaceous plate boundary – data from central Anatolia

The İzmir‐Ankara suture represents part of the boundary between Laurasia and Gondwana along which a wide Tethyan ocean was subducted. In northwest Turkey, it is associated with distinct oceanic subduction‐accretion complexes of Late Triassic, Jurassic and Late Cretaceous ages. The Late Triassic and Jurassic accretion complexes consist predominantly of basalt with lesser amounts of shale, limestone, chert, Permian (274 Ma zircon U‐Pb age) metagabbro and serpentinite, which have undergone greenschist facies metamorphism. Ar‐Ar muscovite ages from the phyllites range from 210 Ma down to 145 Ma with a broad southward younging. The Late Cretaceous subduction‐accretion complex, the ophiolitic mélange, consists of basalt, radiolarian chert, shale and minor amounts of recrystallized limestone, serpentinite and greywacke, showing various degrees of blueschist facies metamorphism and penetrative deformation. Ar‐Ar phengite ages from two blueschist metabasites are ca. 80 Ma (Campanian). The ophiolitic mélange includes large Jurassic peridotite‐gabbro bodies with plagiogranites with ca. 180 Ma U‐Pb zircon ages. Geochronological and geological data show that Permian to Cretaceous oceanic lithosphere was subducted north under the Pontides from the Late Triassic to the Late Cretaceous. This period was characterized generally by subduction‐accretion, except in the Early Cretaceous, when subduction‐erosion took place. In the Sakarya segment all the subduction accretion complexes, as well as the adjacent continental sequences, are unconformably overlain by Lower Eocene red beds. This, along with the stratigraphy of the Sakarya Zone indicate that the hard collision between the Sakarya Zone and the Anatolide‐Tauride Block took place in Paleocene

The Effects of Cocaine on Different Redox Forms of Cysteine and Homocysteine, and on Labile, Reduced Sulfur in the Rat Plasma Following Active versus Passive Drug Injections

Received: 28 November 2012 / Revised: 19 April 2013 / Accepted: 6 May 2013 / Published online: 16 May 2013 The Author(s) 2013. This article is published with open access at Springerlink.comThe aim of the present studies was to evaluate cocaine-induced changes in the concentrations of different redox forms of cysteine (Cys) and homocysteine (Hcy), and products of anaerobic Cys metabolism, i.e., labile, reduced sulfur (LS) in the rat plasma. The above-mentioned parameters were determined after i.p. acute and subchronic cocaine treatment as well as following i.v. cocaine self-administration using the yoked procedure. Additionally, Cys, Hcy, and LS levels were measured during the 10-day extinction training in rats that underwent i.v. cocaine administration. Acute i.p. cocaine treatment increased the total and protein-bound Hcy contents, decreased LS, and did not change the concentrations of Cys fractions in the rat plasma. In turn, subchronic i.p. cocaine administration significantly increased free Hcy and lowered the total and protein-bound Cys concentrations while LS level was unchanged. Cocaine self-administration enhanced the total and protein-bound Hcy levels, decreased LS content, and did not affect the Cys fractions. On the other hand, yoked cocaine infusions did not alter the concentration of Hcy fractions while decreased the total and protein-bound Cys and LS content. This extinction training resulted in the lack of changes in the examined parameters in rats with a history of cocaine self-administration while in the yoked cocaine group an increase in the plasma free Cys fraction and LS was seen. Our results demonstrate for the first time that cocaine does evoke significant changes in homeostasis of thiol amino acids Cys and Hcy, and in some products of anaerobic Cys metabolism, which are dependent on the way of cocaine administration

EVALUATION OF A HAEMOSTATIC AGENT IN RABBITS

Topical hemostatic agents are applied locally to areas of injured vascular endothelium to control local bleeding. Ankaferd Blood Stopper (ABS) has gained approval in Turkey and Bosnia-Herzegovina as a topical haemostatic agent for external post-surgical and post-dental surgery bleeding. The safety of topical use of ABS has been demonstrated in numerous in vitro and in vivo animal models, as well as in a clinical Phase I trial in humans. ABS, besides its haemostatic activity, also has in vitro anti-infectious and anti-neoplastic effects. To assess potential detrimental effects of intravenous administration of ABS into intact systemic circulation in a rabbit experimental model, one milliliter of ABS was administered intravenously into the systemic circulation of twelve rabbits which were included in the study via the marginal ear vein. Animals were observed for 1 hr before euthanasia was performed by administering 40 mg of intracardiac suxamethonium chloride. In the event of death (cardiopulmonary arrest) before the end of the planned observation period of 60 minutes, time of death was recorded and histopathological examination of the liver and spleen was commenced. Ten rabbits were alive by the end of the planned observation period, without showing any clear signs of discomfort, whereas two animals died within five minutes after systemic administration of intravenous ABS. Postmortem histopathological examination of the livers and spleens of all animals’ revealed findings consistent with hepatic venous outflow obstruction. Systemic intravascular administration of ABS into intact vascular endothelium should never be performed in any setting. Further experimental and clinical studies on this liquid hemostatic agent should proceed by accepting ABS as purely a topical haemostatic agent, to be applied solely to areas of injured vascular endothelium