Journal Staff

This handbook describes a framework for development, validation, and integration of multipurpose simulation models. The presented methodology enables reuse of models in different applications with different purposes. The scope is simulation models representing physical environment, physical aircraft systems or subsystems, avionics equipment, and electronic hardware. The methodology has been developed by a small interdisciplinary team, with experience from Modeling and Simulation (M&S) of vehicle systems as well as development of simulators for verification and training. Special care has been taken to ensure usability of the workflow and method descriptions, mainly by means of 1) a user friendly format, easy to overview and update, 2) keeping the amount of text on an appropriate level, and 3) providing relevant examples, templates, and checklists. A simulation model of an aircraft Environmental Control System (ECS) is used as an example to guide the reader through the workflow of developing and validating multipurpose simulation models

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Variability and Customization of Simulator Products : A Product Line Approach in Model Based Systems Engineering

AIRCRAFT DEVELOPERS, like other organizations within development and manufacturing, are experiencing increasing complexity in their products and growing competition in the global market. Products are built from increasingly advanced technologies and their mechanical, electronic, and software parts grow in number and become more interconnected. Different approaches are used to manage information and knowledge of products in various stages of their lifecycle. "Reuse" and "Model Based Development" are two prominent trends for improving industrial development efficiency. The product line approach is used to reduce the time to create product variants by reusing components. The model based approach provides means to capture knowledge about a system in the early lifecycle stages for usage throughout its entire lifetime. It also enables structured data  management as a basis for analysis, automation, and team collaboration for efficient management of large systems and families of products. This work is focused on the combination of methods and techniques within; modeling and simulation-based development, and (re)use of simulation models through the product line concept. With increasing computational performance and more efficient techniques/tools for building simulation models, the number of models increases, and their usage ranges from concept evaluation to end-user training. The activities related to model verification and validation contribute to a large part of the overall cost for development and maintenance of simulation models. The studied methodology aims to reduce the number of similar models created by different teams during design, testing, and end-user support of industrial products. Results of the work include evaluation of a configurator to customize and integrate simulation models for different types of aircraft simulators that are part of a simulator product family. Furthermore, contribution comprises results where constraints in the primary product family (aircraft) govern the configuration space of the secondary product family (simulators). Evaluation of the proposed methodology was carried out in cooperation with the simulator department for the 39 Gripen fighter aircraft at Saab Aeronautics.FLYGPLANSTILLVERKARE LIKSOM andra industrier inom utveckling och tillverkning, hanterar ökande komplexitet i sina produkter och upplever en större konkurrens på den globala marknaden. Produkter byggs från allt mer avancerad teknologi. Ingående delar av mekanik, elektronik och mjukvara växer i antal och blir allt mer integrerade. Olika metoder används för att hantera information och kunskap om produkter i olika steg av dess livscykel. ”Återanvändning” och ”Modellbaserad utveckling” är två tydliga trender för att öka effektiviteten inom industriell utveckling. Produktfamiljer används för att minska ledtider när man skapar varianter av produkter genom att återanvända färdiga komponenter. Modellbaserade metoder ger möjlighet att tidigt i livscykeln samla kunskap om ett system för att användas under hela systemets livstid. De ger också strukturerad hantering av data som grund för analys, automatisering och samarbete mellan utvecklingsteam, vilket är en förutsättning för effektiv hantering av komplexa system och produkter. Detta arbete är fokuserat på en kombination av metoder och tekniker för; utveckling som baseras på modellering och simulering, och (åter)användning av simuleringsmodeller. Med ökande beräkningsprestanda och effektivare metoder/verktyg för att bygga simuleringsmodeller så ökar antalet modeller och deras användning spänner allt från konceptvärderingen till utbildning av slutanvändare. Arbetet med verifiering och validering av simuleringsmodeller utgör en stor del av deras totala utvecklings- och underhållskostnader. De studerade metoderna syftar till att minska antalet liknande modeller som hanteras av olika team för olika syften, som till exempel; utveckling, verifiering och som stöd för slutanvändare. Resultat av arbete inkluderar utvärdering av en konfigurator för att välja, integrera och anpassa simuleringsmodeller för olika typer av flygplanssimulatorer i en simulatorproduktfamilj. Dessutom bidrar arbetet med en metodik där begränsningarna i den primära produktfamiljen (flygplan) begränsar konfigurationsutrymmet för den sekundära produktfamiljen (simulatorer). Utvärdering av den föreslagna metoden har genomförts i samarbete med simulatoravdelning för flygplan 39 Gripen på Saab Aeronautics

Aircraft Systems Modeling : Model Based Systems Engineering in Avionics Design and Aircraft Simulation

Aircraft developers like other development and manufacturing companies, are experiencing increasing complexity in their products and growing competition in the global market. One way to confront the challenges is to make the development process more efficient and to shorten time to market for new products/variants by using design and development methods based on models. Model Based Systems Engineering (MBSE) is introduced to, in a structured way, support engineers with aids and rules in order to engineer systems in a new way. In this thesis, model based strategies for aircraft and avionics development are studied. A background to avionics architectures and in particular Integrated Modular Avionics is described. The integrating discipline Systems Engineering, MBSE and applicable standards are also described. A survey on available and emerging modeling techniques and tools, such as Hosted Simulation, is presented and Modeling Domains are defined in order to analyze the engineering environment with all its vital parts to support an MBSE approach. Time and money may be saved by using modeling techniques that enable understanding of the engineering problem, state-of-the-art analysis and team communication, with preserved or increased quality and sense of control. Dynamic simulation is an activity increasingly used in aerospace, for several reasons; to prove the product concept, to validate stated requirements, and to verify the final implementation. Simulation is also used for end-user training, with specialized training simulators, but with the same underlying models. As models grow in complexity, and the set of simulation platforms is expanded, new needs for specification, model building and configuration support arise, which requires a modeling framework to be efficient

Saab Aeronautics Handbook for Development of Simulation Models : Public Variant

This handbook describes a framework for development, validation, and integration of multipurpose simulation models. The presented methodology enables reuse of models in different applications with different purposes. The scope is simulation models representing physical environment, physical aircraft systems or subsystems, avionics equipment, and electronic hardware. The methodology has been developed by a small interdisciplinary team, with experience from Modeling and Simulation (M&amp;S) of vehicle systems as well as development of simulators for verification and training. Special care has been taken to ensure usability of the workflow and method descriptions, mainly by means of 1) a user friendly format, easy to overview and update, 2) keeping the amount of text on an appropriate level, and 3) providing relevant examples, templates, and checklists. A simulation model of an aircraft Environmental Control System (ECS) is used as an example to guide the reader through the workflow of developing and validating multipurpose simulation models

Rohypnol : Bruk och missbruk

I arbetet beskrivs hur en person under påverkan av Rohypnol i olika mängder kan pendla mellan liv och död. Med hjälp av litterära källor och samtal med vårdkunnig personal berättas det att en person kan använda Rohypnol som en hjälp för att försätta sig självt i ett stadie där känsla av oövervinnerlighet och styrka dominerar. Den verksamma substansen i Rohypnol, Flunitrazepam, har normaldoseringen 0.5-1.0 mg. Även andra droger som alkohol, cannabis och amfetamin förstärks av flunitrazepam. Denna process kallas läkemedelsinteraktion, och innebär att två olika substanser påverkar varandras egenskaper vad gäller nerbrytningen i levern. Rohypnol tas vanligen oralt i tablettform men kan även krossas och då rökas, samt injiceras efter att ha blandats med vätska. Rohypnol används dessutom av narkomaner, särskilt heroinister som ett komplement till ett redan etablerat missbruk. Genom att studera andra arbeten såsom”Rohypnol – Inte bara ett sömnpiller” framkommer det att Rohypnol ger en förhöjd och en förlängd effekt av heroinet och så gott som alla heroinister brukar preparatet. Antingen för att tända av eller förhöja effekten. Att Rohypnol är farligt att använda tillsammans med andra läkemedel eller droger visas tydligt när medicinskt tillförlitliga internetkällor granskats. Rohypnol kan vara farligt att bruka även utan interaktion med andra droger då dödsfall grundat enbart på bruk av Rohypnol, konstaterats i en studie från rättskemiska och rättsmedicinska avdelningen i Falköping

The scene of Latvian history in Latvian Soviet movies (20th century 40.–80.ies)

Bakalaura darbā „Latvijas vēstures aina latviešu padomju kino (20.gs. 40.-80.g.” tiek aplūkotas divpadsmit nozīmīgākās latviešu veidotās mākslas filmas ar vēsturisku sižetu par Latviju 20.gs., kuras tapušas Padomju Latvijas pastāvēšanas laikā. Bakalaura darba mērķis ir izpētīt šīs filmas, analizējot kā un cik lielā mērā vēsturiskajai īstenībai atbilstoši tajās atspoguļota Latvijas 20.gs. vēsture. Salīdzinot gan padomju, gan mūsdienu presē un literatūrā sniegto informāciju var secināt pirmkārt to, ka padomju laikā mākslas kino bija viens no iespaidīgākajiem attiecīgās varas ideoloģijas propagandas līdzekļiem, kas Latvijas vēsturi atainoja tikai daļēji patiesi. Otrkārt, jāsecina, ka šajās filmās galvenais mērķis nemaz nebija vēstures precīza atainošana, bet gan veiksmīga mākslinieciska un radoša izpaušanās.The bachelor paper “The scene of Latvian history in the Latvian Soviet movies (20th century 40.-80.ies)” deals with twelve most relevant Latvian feature films with historic plots of Latvia in 20th century, that have been made during the period of Soviet Latvia. The aim of the bachelor paper is to research these films, analyzing how and to what degree (corespondingly to Latvias 20th century’s history) they are showing the reality of history. Comparing the given information in the Soviet press and established facts in historiography of today the following conclusions can be driven: firstly, during the Soviet period art cinema was one of the most powerful ways and means of propaganda for the above mentioned authority’s ideology. Secondly, instead of a precise depiction of history the aim of the films was actually a successful artistic and creative expression of oneself