Aus Fehlern in der Softwareentwicklung lernen. Wie durch Fehleranalysen die Prozesse der Anforderungsanalyse und der Qualitätssicherung verbessert werden können

Softwarefehler existieren, seit Menschen Software entwickeln. Fehler können mitunter zu erheblichen wirtschaftlichen Verlusten und im schlimmsten Fall zum Verlust von Leben führen. Viele Fehler können auf Mängel im Prozess der Anforderungsanalyse zurückgeführt werden. Je später ein Anforderungsfehler entdeckt und behoben wird, desto aufwändiger wird die Korrektur. Die vorliegende Arbeit beschreibt, wie aus Fehlern in der Softwareentwicklung gelernt werden kann. Sie beschreibt ein Verfahren zu Fehleranalyse, auf dessen Basis insbesondere Prozesse der Anforderungsanalyse und der Qualitätssicherung verbessert werden können. Ziel der Verbesserungen ist es, Anforderungsfehler und mögliche Folgefehler im Entwurf und der Implementierung zu vermeiden oder zumindest früher zu finden. In dieser Arbeit wird zunächst ein Modell hergeleitet, das erklärt, warum Anforderungsfehler entstehen. Für bestimmte Typen von Anforderungsfehlern werden auf der Grundlage empirische Befunde konkrete Ursachen im Prozess der Anforderungsanalyse aufgezeigt. Dieses Erklärungsmodell ist Bestandteil eines Verfahrens zur Fehleranalyse, das den Anspruch erhebt, über die Auswertung von Fehlern Rückschlüsse über mögliche Ursachen im Prozess zu ziehen. Das Verfahren ist eine Weiterentwicklung der Orthogonal Defect Classification, kurz ODC. ODC wird in der Arbeit ausführlich dargestellt und auf der Grundlage empirischer Befunde kritisch gewürdigt. Das weiterentwickelte Verfahren zur Fehleranalyse wurde im Rahmen einer einjährigen Fallstudie bei dem IT-Dienstleister einer großen deutschen Versicherung erfolgreich angewandt. Hierbei wurden nachträglich reale Fehler von zwei Softwareentwicklungsprojekten einer geschäftskritischen Anwendungssoftware klassifiziert und analysiert, um Verbesserungspotenziale zu identifizieren. Das in der Arbeit entwickelte Verfahren zur Fehleranalyse leistet einen unmittelbaren Beitrag zur Lösung des aufgezeigten Praxisproblems: sie ist ein Instrument, um Prozessmängel der Anforderungsanalyse zu identifizieren, die systematisch Anforderungsfehler und Folgefehler verursachen

Pelvis Magnetic Resonance Imaging to Diagnose Familial Partial Lipodystrophy

Context The diagnosis of familial partial lipodystrophy (FPLD) is currently made based on clinical judgment. Objective There is a need for objective diagnostic tools that can diagnose FPLD accurately. Methods We have developed a new method that uses measurements from pelvic magnetic resonance imaging (MRI) at the pubis level. We evaluated measurements from a lipodystrophy cohort (n = 59; median age [25th-75th percentiles]: 32 [24-44]; 48 females and 11 males) and age- and sex-matched controls (n = 29). Another dataset included MRIs from 289 consecutive patients. Results Receiver operating characteristic curve analysis revealed a potential cut-point of = 2.5 (based on a receiver operating characteristic curve) provided 96.67% (95% CI, 82.78-99.92) sensitivity and 91.38% (95% CI, 81.02-97.14) specificity in the overall cohort and 100.00% (95% CI, 87.23-100.00) sensitivity and 90.00% (95% CI, 76.34-97.21) specificity in females for the diagnosis of FPLD. When this approach was tested in a larger dataset of random patients, FPLD was differentiated from subjects without lipodystrophy with 96.67% (95% CI, 82.78-99.92) sensitivity and 100.00% (95% CI, 98.73-100.00) specificity. When only women were analyzed, the sensitivity and the specificity was 100.00% (95% CI, 87.23-100.00 and 97.95-100.00, respectively). The performance of gluteal fat thickness and pubic/gluteal fat thickness ratio was comparable to readouts performed by radiologists with expertise in lipodystrophy. Conclusion The combined use of gluteal fat thickness and pubic/gluteal fat ratio from pelvic MRI is a promising method to diagnose FPLD that can reliably identify FPLD in women. Our findings need to be tested in larger populations and prospectively

A Large-Scale Outbreak of Trichinellosis Caused by Trichinella britovi in Turkey

WOS: 000263046400003PubMed ID: 18705658An outbreak of trichinellosis occurred in Izmir, Turkey, between January and March 2004. The outbreak was caused by the consumption of raw meat balls made of beef deceptively mixed with pork infected with Trichinella britovi. A total of 1098 people who had consumed this food either in 14 restaurants or from the street vendors located in three different neighbourhoods, consulted six different healthcare centres with a wide range of clinical signs and symptoms. Of them, 418 (38.1%) patients fulfilled the criteria for the diagnosis of acute trichinellosis. The most commonly observed signs and symptoms were myalgia (89.2%), arthralgia (69.9%) and eyelid (67%) and facial oedema (65.8%). High levels of creatinine kinase (69.3%) and lactate dehydrogenase (93.8%) with leucocytosis (> 10 000/mm(3), 58.9%) and eosinophilia (> 1000/mm(3), 60.5%) were the most prominent laboratory findings. All, but 13 of these patients were treated with mebendazole or albendazole. Based on the physicians' assessments of disease severity, 78 (19%) patients were additionally given prednisolone in whom a significantly more rapid recovery of clinical signs and symptoms (e.g. fever, myalgia, facial and eyelid oedema) was observed, with a rapid improvement in leucocytosis, eosinophilia and muscle enzymes, compared with those, who had not received corticosteroids (P < 0.05). Beef illegally mixed with pork of unknown origin, by a wholesale butcher who had sold this product to restaurants and street vendors at a lower price than the prevailing market price of beef, was the cause of this large-scale outbreak in a country with a predominantly Muslim population

A large-scale outbreak of trichinellosis caused by Trichinella britovi in Turkey.

An outbreak of trichinellosis occurred in Izmir, Turkey, between January and March 2004. The outbreak was caused by the consumption of raw meat balls made of beef deceptively mixed with pork infected with Trichinella britovi. A total of 1098 people who had consumed this food either in 14 restaurants or from the street vendors located in three different neighbourhoods, consulted six different healthcare centres with a wide range of clinical signs and symptoms. Of them, 418 (38.1%) patients fulfilled the criteria for the diagnosis of acute trichinellosis. The most commonly observed signs and symptoms were myalgia (89.2%), arthralgia (69.9%) and eyelid (67%) and facial oedema (65.8%). High levels of creatinine kinase (69.3%) and lactate dehydrogenase (93.8%) with leucocytosis (> 10 000/mm(3), 58.9%) and eosinophilia (> 1000/mm(3), 60.5%) were the most prominent laboratory findings. All, but 13 of these patients were treated with mebendazole or albendazole. Based on the physicians' assessments of disease severity, 78 (19%) patients were additionally given prednisolone in whom a significantly more rapid recovery of clinical signs and symptoms (e.g. fever, myalgia, facial and eyelid oedema) was observed, with a rapid improvement in leucocytosis, eosinophilia and muscle enzymes, compared with those, who had not received corticosteroids (P < 0.05). Beef illegally mixed with pork of unknown origin, by a wholesale butcher who had sold this product to restaurants and street vendors at a lower price than the prevailing market price of beef, was the cause of this large-scale outbreak in a country with a predominantly Muslim population