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- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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- Andersson, Niklas, et al.
(författare)
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Model-Based Comparison of Batch and Continuous Preparative Chromatography in the Separation of Rare Earth Elements
- 2014
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 53:42, s. 16485-16493
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Tidskriftsartikel (refereegranskat)abstract
- The demand for rare earth elements (REEs) is growing, while the future supply is uncertain. Their unique electronic characteristics make them irreplaceable, and the commercial value of pure fractions is high. A model-based simulation study is presented that compares batch chromatography with the twin-column MCSGP (multicolumn countercurrent solvent gradient purification) process for ion-exchange chromatography of the four-component system neodymium, samarium, europium, and gadolinium. The last three components are considered products with individual purity requirements of 99%. The twin-column process has been shown to be a good alternative to the batch process regarding modifier consumption and productivity since it enables internal recycling to achieve high purities. A new cut strategy for MCSGP is applied where subfractions are taken from each outlet. Two multiobjective optimizations with yield, solvent productivity, and productivity objectives show that the MCSGP process is a better alternative than batch chromatography.
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- Borg, Andreas, 1976-, et al.
(författare)
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A Method for Improving the Treatment of Capacity Requirements in Large Telecommunication Systems
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Non-functional requirements crosscut functional models and are more difficult to enforce in system models. This paper describes a long-term research collaboration regarding capacity requirements between Linköping University and Ericsson AB. We describe an industrial case study on non-functional requirements as a background. Succeeding efforts dedicated to capacity include a detailed description of the term, a best practice inventory within Ericsson, and a pragmatic approach for how to annotate UML models with capacity information. The results are also represented as a method plug-in to the OpenUP software process and an anatomy facilitating the possibility to assess and improve an organization’s abilities to develop for capacity. The results combine into a method for how to improve the treatment of capacity requirements in large-scale software systems. Both product and process views are included, with emphasis on the latter.
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- Borg, Andreas, 1976-, et al.
(författare)
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Extending the OpenUP/Basic Requirements Discipline to Specify Capacity Requirements
- 2007
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Ingår i: Requirements Engineering Conference, 2007. RE '07. - : IEEE Computer Society. - 9780769529356 ; , s. 328-333
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Konferensbidrag (refereegranskat)abstract
- Software processes, such as RUP and agile methods, focus their requirements engineering part on use cases and thus functional requirements. Complex products, such as radio network control software, need special handling of non-functional requirements as well. We describe how we used the eclipse process framework to augment the open and minimal OpenUP/basic process with improvements found in management of capacity requirements in a case-study at Ericsson. The result is compared with another project improving RUP to handle performance requirements. The major differences between the improvements are that 1) they suggest a special, dedicated performance manager role and we suggest that present roles are augmented, 2) they suggest a bottom-up approach to performance verification while we focus on system performance first, i.e. top-down. Further, we suggest augmenting UMLl-2 models with capacity attributes to improve information flow from requirements to implementation.
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- Borg, Andreas, 1976-, et al.
(författare)
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Good Practice and Improvement Model of Handling Capacity Requirements of Large Telecommunication Systems
- 2006
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Ingår i: 14th IEEE International Requirements Engineering Conference (RE'06), Minneapolis/S:t Paul. - Los Alamitos, CA : IEEE Computer Society. - 0769525555 - 9780769525556 ; , s. 245-250
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Konferensbidrag (refereegranskat)abstract
- There is evidence to suggest that the software industry has not yet matured as regards management of nonfunctional requirements (NFRs). Consequently the cost of achieving required quality is unnecessarily high. To try and avoid this, the telecommunication systems provider Ericsson defined a research task to try and improve the management of requirements for capacity, which is one of the most critical NFRs. Linkoping University joined in the effort and conducted an interview series to investigate good practice within different parts of the company. Inspired by the interviews and an ongoing process improvement project a model for improvement was created and activities were synthesized. This paper contributes the results from the interview series, and details the subprocesses of specification that should be improved. Such improvements are about understanding the relationship between numerical entities at all system levels, augmenting UML specifications to make NFRs visible, working with time budgets, and testing the sub system level components on the same level as they are specified.
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- Borg, Andreas, 1976-, et al.
(författare)
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Integrating an Improvement Model of Handling Capacity Requirements with OpenUP/Basic Process
- 2007
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Ingår i: 13th International working conference on Requirements Engineering: Foundations for Software Quality (REFSQ'07), Trondheim, Norway. - Berlin Heidelberg : Springer. - 9783540730309 ; , s. 341-354
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Konferensbidrag (refereegranskat)abstract
- Contemporary software processes and modeling languages have a strong focus on Functional Requirements (FRs), whereas information of Non-Functional Requirements (NFRs) are managed with text-based documentation and individual skills of the personnel. In order to get a better understanding of how capacity requirements are handled, we carried out an interview series with various branches of Ericsson. The analysis of this material revealed 18 Capacity Sub-Processes (CSPs) that need to be attended to create a capacity-oriented development. In this paper we describe all these sub-processes and their mapping into an extension of the OpenUP/Basic software process. Such an extension will support a process engineer in realizing the sub-processes, and has at the same time shown that there are no internal inconsistencies of the CSPs. The extension provides a context for continued research in using UML to support negotiation between requirements and existing design.
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- Borg, Andreas, 1976-
(författare)
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Processes and Models for Capacity Requirements in Telecommunication Systems
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Capacity is an essential quality factor in telecommunication systems. The ability to develop systems with the lowest cost per subscriber and transaction, that also meet the highest availability requirements and at the same time allow for scalability, is a true challenge for a telecommunication systems provider. This thesis describes a research collaboration between Linköping University and Ericsson AB aimed at improving the management, representation, and implementation of capacity requirements in large-scale software engineering.An industrial case study on non-functional requirements in general was conducted to provide the explorative research background, and a richer understanding of identified difficulties was gained by dedicating subsequent investigations to capacity. A best practice inventory within Ericsson regarding the management of capacity requirements and their refinement into design and implementation was carried out. It revealed that capacity requirements crosscut most of the development process and the system lifecycle, thus widening the research context considerably. The interview series resulted in the specification of 19 capacity sub-processes; these were represented as a method plug-in to the OpenUP software development process in order to construct a coherent package of knowledge as well as to communicate the results. They also provide the basis of an empirically grounded anatomy which has been validated in a focus group. The anatomy enables the assessment and stepwise improvement of an organization’s ability to develop for capacity, thus keeping the initial cost low. Moreover, the notion of capacity is discussed and a pragmatic approach for how to support model-based, function-oriented development with capacity information by its annotation in UML models is presented. The results combine into a method for how to improve the treatment of capacity requirements in large-scale software systems.
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