A discrete methodology for controlling the sign of curvature and torsion for NURBS

This paper develops a discrete methodology for approximating the so-called convex domain of a NURBS curve, namely the domain in the ambient space, where a user-specified control point is free to move so that the curvature and torsion retains its sign along the NURBS parametric domain of definition. The methodology provides a monotonic sequence of convex polyhedra, converging from the interior to the convex domain. If the latter is non-empty, a simple algorithm is proposed, that yields a sequence of polytopes converging uniformly to the restriction of the convex domain to any user-specified bounding box. The algorithm is illustrated for a pair of planar and a spatial Bézier configuration

Semantically annotated hypermedia services

Hypermedia systems’ researchers investigate the various approaches in the way documents and resources are linked, navigated and stored in a distributed environment. Unfortunately, those systems fail to provide effortlessly usable discrete services, since it is difficult both to discover and to invoke any of them. This paper proposes the usage of emerging technologies that try to augment the Web resources with semantics in order to provide Hypermedia services that can be easily discovered, and integrated by potential third party developers. In this context, we analyze the benefits for the Hypermedia community upon the adoption of Semantic Web technologies for the description of Hypermedia services, and we implement an initial corresponding ontology

41P. Practical Lessons Learned while Developing Web 2.0 Collaboration Services for Communities of Practice

Although a plethora of Web 2.0 applications exist today, there is little literature reporting on experiences, concrete recommendations or best practices when developing such applications. The scarcity of such records makes it difficult for developers to determine how best to support the practices of communities with the use of Web 2.0 technologies. In this paper, we report on eight practical lessons learned while developing Web 2.0 collaboration services for Communities of Practice in the framework of a three years long European research project on Technology Enhanced Learning. The main objective of this project was to investigate how Web 2.0 technologies could impact the communication and collaboration needs of Communities of Practice interacting online and, conversely, how new interaction needs could impact Web 2.0 technology. The above lessons are presented in a way that could aid people engaged in various phases of the development of Web-based collaboration support services

Σύγκριση μεθόδων οριοθέτησης Αιγιαλού

182 σ.Η οριοθέτηση της ελληνικής παράκτιας ζώνης είναι αναγκαία και σημαντική για την ολοκληρωμένη ανάπτυξη των παράκτιων περιοχών και μέσα στα πλαίσια ολοκλήρωσης του έργου του Εθνικού Κτηματολογίου γίνεται επιτακτική η ανάγκη καθορισμού των ορίων του προς τη θάλασσα, που είναι η οριογραμμή του αιγιαλού. Για τον λόγο αυτό η Κτηματολόγιο Α.Ε. ολοκλήρωσε το έργο καθορισμού της Προκαταρκτικής Οριογραμμής του Αιγιαλού (ΠΟΑ) με φωτοερμηνευτικές μεθόδους και τεχνικές. Σκοπός της παρούσας εργασίας είναι η σύγκριση της υφιστάμενης μεθόδου καθορισμού των ορίων του αιγιαλού με επιτόπια αυτοψία, με την μέθοδο καθορισμού της ΠΟΑ από την Κτηματολόγιο Α.Ε. με φωτοερμηνευτικές μεθόδους και τεχνικές. Για την σύγκριση των δύο οριογραμμών επιλέχθηκαν 22 παράκτιες περιοχές βάση κριτηρίων, έτσι ώστε το δείγμα να είναι αντιπροσωπευτικό του ελληνικού παράκτιου χώρου και ο προσδιορισμός των αποτελεσμάτων να είναι όσο το δυνατόν πιο αντικειμενικός. Προτείνονται τρεις μέθοδοι σύγκρισης, στην πρώτη μέθοδο συγκρίνονται οι επιφάνειες που σχηματίζονται μεταξύ των δύο οριογραμμών, στη δεύτερη μέθοδο συγκρίνονται οι κάθετες αποστάσεις που περιέχονται μεταξύ των δύο οριογραμμών και στην τρίτη μέθοδο συγκρίνονται οι κάθετες αποστάσεις πού περιέχονται μεταξύ των κριτηρίων χάραξης της ΠΟΑ και της καθορισμένης οριογραμμής του αιγιαλού. Τα αποτελέσματα που προκύπτουν δίνουν μια πρώτη εικόνα, εάν μπορεί η ΠΟΑ να χρησιμοποιηθεί σε μεταγενέστερο στάδιο από τις αρμόδιες Υπηρεσίες και Επιτροπές του Υπουργείου Οικονομίας και Οικονομικών για την επίσπευση των διαδικασιών καθορισμού και θεσμοθέτησης του αιγιαλού, του παλαιού αιγιαλού, της παραλίας, της όχθης και της παρόχθιας ζώνης. Λέξεις Κλειδιά : Καθορισμένη Οριογραμμή Αιγιαλού, Προκαταρκτική Οριογραμμή Αιγιαλού, Μέθοδοι Σύγκρισης των δύο Οριογραμμών.The delineation of the Greek coastal zone is necessary for the integrated development of the coastal areas and for the completion of the Hellenic Cadastre. Ktimatologio SA (which is the management service of Hellenic Cadastre) completed the work of delineating the Preliminary Coastal Zone throught photointerpretation methods and techniques. This Thesis Aimes to compare the institutional method to delineating the coastal zone on the spot survey, with the Ktimatologio SA method of delineating the Preliminary Coastal Zone with photointerpretation methods and techniques. To compare the two borderlines 22 coastal areas were selected based on benchmarks, for the objective determination of results. Three comparison methods were applied: the first method compares the surfaces between the two borderlines, the second method compares the vertical distances between the two borderlines and the third method compares the vertical distances between the two borderlines based on the data selection of Preliminary Coastal Zone. The results of the comparison methods give a first impression of whether this data can be used, at a later stage, by the Services and Committees of the Ministry of Economy and Finance for speeding up the official coastal zones delineation proccess. Key words : Preliminary Coastal Zone, Institutional Coastal Zone delineation method, Comparison Methods of the two coastlines.Γεράσιμος Χ. Καρούσο

CoPe_it! - Supporting collaboration, enhancing learning

CoPe_it! is an innovative web-based tool that complies with collaborative practices to provide members of communities with the appropriate means to manage individual and collective knowledge, and collaborate towards the solution of diverse issues. In this article, we demonstrate its applicability in tackling data-intensive collaboration settings, which are characterized by big volumes of complex and interrelated data obtained from diverse sources, and knowledge expressed by diverse participants. We focus on issues related to the representation of such settings and the proposed approach towards making it easier for participants to follow the evolution of a collaboration, comprehend it in its entirety, and meaningfully aggregate data in order to resolve the issue under consideration

Assessing customs performance in the Mediterranean ports. KPI selection and Best practices identification as part of the MEDNET project

[EN] The seamless flow of goods, people and investments across the Mediterranean necessitates a well-functioning port and transport system. More efficient port operations enhance seamless logistics and promote safety, efficiency, interoperability and interconnectivity of transport networks in the Mediterranean area.To promote the exchange of knowledge and expertise relevant to port and customs procedures and simplification of clearance for vessels and cargoes in the Mediterranean, the MEDNET project was launched. As part of the project a common evaluation framework for the performance of ports in the form of a set of Key Performance Indicators (KPIs) together with a list of the best practices in terms of operations and customs procedures was developed.In total, 50 ports were analyzed and given a KPI regarding traffic, financial, operational and human resources, sustainability and customs procedures. The values were latter crossed with the current good practices on operation in terms of customs procedures. And a small correlation between KPIs performance and implantation degree of good practices in customs procedures was found. This presentation exposes the methodology to assess the ports’ performance and the best practices identification.Morales Fusco, P.; Saurí Marchán, S.; Lekka, AM.; Karousos, I. (2016). Assessing customs performance in the Mediterranean ports. KPI selection and Best practices identification as part of the MEDNET project. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1482-1500. https://doi.org/10.4995/CIT2016.2015.4221OCS1482150

Establishing usability heuristics for heuristics evaluation in a specific domain: is there a consensus?

Heuristics evaluation is frequently employed to evaluate usability. While general heuristics are suitable to evaluate most user interfaces, there is still a need to establish heuristics for specific domains to ensure that their specific usability issues are identified. This paper presents a comprehensive review of 70 studies related to usability heuristics for specific domains. The aim of this paper is to review the processes that were applied to establish heuristics in specific domains and identify gaps in order to provide recommendations for future research and area of improvements. The most urgent issue found is the deficiency of validation effort following heuristics proposition and the lack of robustness and rigour of validation method adopted. Whether domain specific heuristics perform better or worse than general ones is inconclusive due to lack of validation quality and clarity on how to assess the effectiveness of heuristics for specific domains. The lack of validation quality also affects effort in improving existing heuristics for specific domain as their weaknesses are not addressed

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

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