Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 84
Filtrar
1.
BMC Public Health ; 24(1): 2820, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39402467

RESUMO

BACKGROUND: Antimicrobial resistance is a global patient safety priority and inappropriate antimicrobial use is a key contributing factor. Evidence have shown that delayed (back-up) antibiotic prescriptions (DP) are an effective and safe strategy for reducing unnecessary antibiotic consumption but its use is controversial. METHODS: We conducted a realist review to ask why, how, and in what contexts general practitioners (GPs) use DP. We searched five electronic databases for relevant articles and included DP-related data from interviews with healthcare professionals in a related study. Data were analysed using a realist theory-driven approach - theorising which context(s) influenced (mechanisms) resultant outcome(s) (context-mechanism-outcome-configurations: CMOCs). RESULTS: Data were included from 76 articles and 41 interviews to develop a program theory comprising nine key and 56 related CMOCs. These explain the reasons for GPs' tolerance of risk to different uncertainties and how these may interact with GPs' work environment, self-efficacy and perceived patient concordance to make using DP as a safety-net or social tool more or less likely, at a given time-point. For example, when a GP uses clinical scores or diagnostic tests: a clearly high or low score/test result may mitigate scientific uncertainty and lead to an immediate or no antibiotic decision; an intermediary result may provoke hermeneutic (interpretation-related) uncertainty and lead to DP becoming preferred and used as a safety net. Our program theory explains how DP can be used to mitigate some uncertainties but also provoke or exacerbate others. CONCLUSION: This review explains how, why and in what contexts GPs are more or less likely to use DP, as well as various uncertainties GPs face which DP may mitigate or provoke. We recommend that efforts to plan and implement interventions to optimise antibiotic prescribing in primary care consider these uncertainties and the contexts when DP may be (dis)preferred over other interventions to reduce antibiotic prescribing. We also recommend the following and have included example activities for: (i) reducing demand for immediate antibiotics; (ii) framing DP as an 'active' prescribing option; (iii) documenting the decision-making process around DP; and (iv) facilitating social and system support.


Assuntos
Antibacterianos , Padrões de Prática Médica , Atenção Primária à Saúde , Humanos , Antibacterianos/uso terapêutico , Incerteza , Padrões de Prática Médica/estatística & dados numéricos , Clínicos Gerais/psicologia , Prescrições de Medicamentos/estatística & dados numéricos , Prescrição Inadequada/prevenção & controle
2.
Entropy (Basel) ; 26(8)2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39202137

RESUMO

Remote data backup technology avoids the risk of data loss and tampering, and has higher security compared to local data backup solutions. However, the data transmission channel for remote data backup is not secure, and the backup server cannot be fully trusted, so users usually encrypt the data before uploading it to the remote server. As a result, how to protect this encryption key is crucial. We design a User-Centric Design (UCD) data backup scheme based on multi-factor authentication to protect this encryption key. Our scheme utilizes a secret sharing scheme to divide the encryption key into three parts, which are stored in the laptop, the smart card, and the server. The encryption key can be easily reconstructed from any two parts with user's private information password, identity and biometrics. As long as the biometrics has enough entropy, our scheme can resist replay attacks, impersonation user attacks, impersonation server attacks, malicious servers and offline password guessing attacks.

3.
Disabil Health J ; : 101677, 2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39095293

RESUMO

BACKGROUND: The COVID-19 pandemic was an emergency event during which backup plans became widely relevant. Although backup plans are required for Medicaid-funded Home and Community Based Services (HCBS) as a key risk management strategy, we know little about their effectiveness. OBJECTIVE: The purpose of this study was to explore whether backup plans and care coordination met the needs of HCBS consumers during the COVID-19 pandemic in Kansas. METHODS: An interactive, convergent mixed-methods design within a community-based participatory research framework was used. Data came from 70 in-depth interviews with HCBS consumers, caregivers, workers, and providers, as well as 100 surveys from consumers, asking about experiences receiving or providing care during the COVID-19 pandemic in Kansas. Inductive coding was used to identify major themes for the qualitative data. Descriptive and bivariate analysis were used for quantitative data. RESULTS: One-third of survey respondents reported not having a backup plan and 39% went without formal homecare services for at least 2 consecutive weeks. The pandemic exacerbated and exposed deficiencies in care coordination and backup plans in a managed care environment. Interview participants expressed great need for backup workers during the pandemic but struggled to find these supports. Although family, friends, and providers stepped in to help fill gaps, there remained many unmet care needs. CONCLUSIONS: Findings indicate that improvements are needed in care coordination to support the development and maintenance of backup plans that can be successfully drawn on to avoid interruptions to care.

4.
Indian J Anaesth ; 68(6): 547-552, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38903261

RESUMO

Background and Aims: The head-elevated laryngoscopy position (HELP) and a 25° backup have been proposed to enhance glottic visualisation, yet concerns about ergonomic discomfort hinder their widespread adoption. This study compares the comfort and posture adopted by anaesthesiologists while performing laryngoscopy and tracheal intubation with patients in HELP while in a supine position or with 25° backup. Methods: The study included 48 patients aged 18-60 years with normal airways and 12 experienced anaesthesiologists. Patients were randomised into two groups using permuted block randomisation. Anaesthesiologists performed laryngoscopy and intubation in supine HELP and 25° backup HELP positions. Anaesthesiologist's posture was determined by measuring the angles of neck, wrist, elbow, back and knee joints, which were compared using Student's t-test, and subjective comfort assessed on a Likert scale was compared using the Chi-square test. As mentioned by the anaesthesiologist, Cormack- Lehane grading was also noted and compared using a Chi-square test between groups, taking a P value <0.05 as significant. Results: Both positions demonstrated comparable anaesthesiologist posture (P = 0.919) and comfort (P = 0.644). However, the 25° backup HELP positions significantly improved Cormack-Lehane grades, with 68% achieving grade 1 compared to 31% in the supine HELP group (P = 0.012). Haemodynamic stability and tracheal intubation time showed no significant differences between the groups (P = 0.475 and 0.117, respectively), and no complications were reported in either group. Conclusion: Anaesthesiologists' posture and comfort during laryngoscopy and tracheal intubation are similar between supine and 25° backup in patients with easy airways.

5.
Europace ; 26(7)2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38874449

RESUMO

Ventricular backup leads may be considered in selected patients with His bundle pacing (HBP), but it remains unknown to what extent this is useful. A total of 184 HBP patients were studied. At last follow-up, 147 (79.9%) patients retained His bundle capture at programmed output. His bundle pacing lead revision was performed in 5/36 (13.9%) patients without a backup lead and in 3/148 (2.0%) patients with a backup lead (P = 0.008). One patient without a backup lead had syncope due to atrial oversensing. Thus, implantation of ventricular backup leads may avoid lead revision and adverse events in selected HBP patients.


Assuntos
Fascículo Atrioventricular , Estimulação Cardíaca Artificial , Marca-Passo Artificial , Humanos , Fascículo Atrioventricular/fisiopatologia , Masculino , Feminino , Estimulação Cardíaca Artificial/métodos , Idoso , Resultado do Tratamento , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais , Estudos Retrospectivos , Fatores de Tempo , Eletrodos Implantados
6.
Sensors (Basel) ; 24(8)2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38676245

RESUMO

Fingerprint recognition systems have achieved widespread integration into various technological devices, including cell phones, computers, door locks, and time attendance machines. Nevertheless, individuals with worn fingerprints encounter challenges when attempting to unlock original fingerprint systems, which results in disruptions to their daily activities. This study explores two distinct methods for fingerprint backup: traditional fingerprint impression and 3D printing technologies. Unlocking tests were conducted on commonly available optical fingerprint lock-equipped cell phones to assess the efficacy of these methods, particularly in unlocking with worn fingerprints. The research findings indicated that the traditional fingerprint impression method exhibited high fidelity in reproducing fingerprint patterns, achieving an impressive unlocking success rate of 97.8% for imprinting unworn fingerprints. However, when dealing with worn fingerprints, the traditional fingerprint impression technique showed a reduced unlocking success rate, progressively decreasing with increasing degrees of finger wear. In contrast, 3D-printed backup fingerprints, with image processing and optimization of ridge height, mitigated the impact of fingerprint wear on the unlocking capability, resulting in an unlocking success rate of 84.4% or higher. Thus, the utilization of 3D printing technology proves advantageous for individuals with severely worn or incomplete fingerprints, providing a viable solution for unforeseen circumstances.


Assuntos
Dermatoglifia , Impressão Tridimensional , Humanos , Dedos/fisiologia , Processamento de Imagem Assistida por Computador/métodos
8.
New Phytol ; 240(4): 1381-1389, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37724752

RESUMO

Gene duplication is a powerful source of biological innovation giving rise to paralogous genes that undergo diverse fates. Redundancy between paralogous genes is an intriguing outcome of duplicate gene evolution, and its maintenance over evolutionary time has long been considered a paradox. Redundancy can also be dubbed 'a geneticist's nightmare': It hinders the predictability of genome editing outcomes and limits our ability to link genotypes to phenotypes. Genetic studies in yeast and plants have suggested that the ability of ancient redundant duplicates to compensate for dosage perturbations resulting from a loss of function depends on the reprogramming of gene expression, a phenomenon known as active compensation. Starting from considerations on the stoichiometric constraints that drive the evolutionary stability of redundancy, this review aims to provide insights into the mechanisms of active compensation between duplicates that could be targeted for breaking paralog dependencies - the next frontier in plant functional studies.


Assuntos
Duplicação Gênica , Saccharomyces cerevisiae , Genótipo , Fenótipo , Saccharomyces cerevisiae/genética , Evolução Molecular , Genes Duplicados , Modelos Genéticos
9.
Artigo em Inglês | MEDLINE | ID: mdl-37192962

RESUMO

Disruptions to key lifelines, especially electrical power, can cause outsized impacts on human functioning. The state of the art on developed countries has focused on enhancing resilience to electrical grid infrastructure but has neglected to track changes regarding how the private market has developed electricity continuity measures over time. Backup generators are among the most accessible tools to maintain electricity continuity in case of power failure, but their role as a buffer remains understudied outside the technical domain, along with the humanitarian and emergency response sectors. This paper analyzes generator sales across the U.S. to understand some underlying trends that may have influenced changes in consumer preference for electricity resilience. Reports from major backup generator sellers and import data of backup generators reveal an increase in backup generators across the U.S. and find that private demand for energy resilience is likely increasing due to consumers' perceived risk and rising levels of intolerance to power disruptions. The discussion finds that an increase in private demand and use of backup generators may be impacting electricity resilience at a communal and societal level, which seems to be underexamined by studies focusing on private generator usage in the U.S..

10.
Cardiovasc Interv Ther ; 38(4): 395-405, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37184629

RESUMO

We developed the smallest diameter guide-extension catheter (GUIDE PLUS® 5Fr) to enable a new technique, the guide-extension proximal locking method (GP-Lock), and assessed its efficacy in the present experimental and clinical study. Sufficient guide catheter backup is sometimes crucial for PCI. We developed the KIWAMI-Lock direct anchoring method to obtain the strongest backup force by locking a Kiwami® 4Fr child catheter (Terumo Corp. Tokyo, Japan) directly to the coronary artery by ballooning from outside the child catheter. However, this method is complicated due to the requirement for a child catheter. We compared the backup power of the GP-Lock method and other conventional methods in an experimental study and compared the procedural outcomes of 17 cases treated using the initial GP-Lock method with 17 cases using the recent KIWAMI-Lock method before GP-Lock. The GP-Lock method had the highest backup force among the methods examined (GP-Lock: 293.7 ± 10.2 g force (gf), KIWAMI-Lock: 270.4 ± 12.9 gf, side branch balloon anchoring technique: 182.7 ± 8.1 gf, respectively, P < 0.0001). The preparation time was significantly shorter for the GP-Lock group than the KIWAMI-Lock group (5.0 [4.0, 5.0] min vs. 11.0 [8.0, 13.0] min, respectively, P < 0.001). The GP-Lock method makes it possible to easily obtain the strongest backup force, which can overcome situations where devices cannot pass through, especially in complex PCI procedures.


Assuntos
Intervenção Coronária Percutânea , Criança , Humanos , Intervenção Coronária Percutânea/métodos , Desenho de Equipamento , Catéteres , Cateterismo , Padrões de Referência , Resultado do Tratamento , Angiografia Coronária
12.
J Maxillofac Oral Surg ; 22(Suppl 1): 98-104, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37041957

RESUMO

Introduction: Up to the second half of the twentieth century, pedicled flaps marked the gold standard in reconstructive surgery. Followed by the introduction of microsurgical techniques, these flaps were increasingly abandoned. We conducted a retrospective study to determine the value of two-stage pedicle flaps in modern maxillofacial reconstruction. Material & Methods: A chart review from October 2017 to November 2020 was performed to identify patients who were treated by a two-stage pedicle flap in our Department of Oral and Maxillofacial Surgery. Results: A total of 31 patients, 17 female and 14 males received 36 two-stage pedicle flaps. All patients were in noticeably impaired health condition with a majority of ASA-score 3. The defect location mainly contained extraoral resections (58.3%). A variety of flaps were harvested consisting of buccal flaps, Abbe flaps, forehead flaps, deltopectoral flaps, nasolabial flaps, and a tubed flap. Discussion: The study outlines two indications for the use of two-stage pedicle flaps. Firstly, as a back-up strategy in heavily pre-treated wound beds and secondly in an almost contrarily indication as a first-choice reconstructive option of the facial skin in esthetic demanding cases. Conclusion: The timesaving and straight forward surgical approach as well as their low postsurgical complications and strong long-time success rates secure the two-stage pedicle flap a justified niche role in times of microsurgical maxillofacial reconstruction. Supplementary Information: The online version contains supplementary material available at 10.1007/s12663-021-01635-9.

13.
Disabil Rehabil ; : 1-7, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36843538

RESUMO

PURPOSE: Prostheses designed for daily use are often inappropriate for high-level activities and/or are susceptible to water damage and mechanical failure. Secondary prostheses, such as activity-specific or back-up prostheses, are typically required to facilitate uninterrupted participation in desired life pursuits. This study estimated the prevalence of secondary prosthesis use in a large, national sample of lower limb prosthesis users (LLPUs). METHODS: We conducted a secondary analysis of survey data from three cross-sectional studies that assessed mobility in LLPUs. Descriptive statistics were used to determine the percentage of secondary prosthesis users and percentages of LLPUs that used different type(s) of secondary prosthesis(es). Secondary prosthesis users and non-users were compared to identify differences in participant characteristics between groups. RESULTS: Of participants in the analysis (n = 1566), most (65.8%) did not use a secondary prosthesis. The most common secondary prosthesis types were back-up (19.2%) and activity-specific prostheses (13.5%). Secondary prosthesis users differed significantly from non-users with respect to gender, race, and other characteristics. CONCLUSIONS: Results suggest that secondary prosthesis use for most LLPUs is limited and may differ based on users' demographic and clinical characteristics. Future research should determine how LLPUs' health-related quality-of-life outcomes are affected by access to and use of secondary prostheses.Implications for RehabilitationSecondary prostheses, including activity-specific, back-up, and shower prostheses, have the potential to improve function, mobility, and participation for people who use lower limb prostheses.Most lower limb prosthesis users do not use secondary prostheses, and access to these devices may be related to users' demographic and clinical characteristics.Rehabilitation professionals play a key role in facilitating prosthesis users' access to secondary prostheses and should advocate for those who need them.

14.
Eur J Med Res ; 28(1): 101, 2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36841827

RESUMO

BACKGROUND: Guide extension catheters (GEC) are widely applied to cope with insufficient backup support in complex percutaneous coronary intervention (PCI). In the study, we aim to evaluate the feasibility and safety with a novel 5-4F tapered GEC used in complex lesion. METHODS: The single-center retrospective study enrolled a total of 615 patients, in whom the 5F or 5-4F Expressman GEC was used to facilitate PCI procedure. Demographic and procedural data were collected. RESULTS: 5F GEC was used in 295 patients and 5-4F tapered GEC in 320 patients. The average age was 63.6 ± 11.0 years and 81.6% of the patients were male. Severe calcification and chronic total occlusion (CTO) were the commonest indication for the GEC use. The 5-4F tapered GEC was frequently used in active greeting technique (AGT) during CTO intervention procedure than 5F GEC (6.1% vs. 13.1%, p < 0.001). The average depth of intubation was 41.5 ± 19.6 mm for the 5-4F tapered GEC and 24.4 ± 15.1 mm for 5F GEC (p < 0.001). The rate of successful device delivery with 5-4F GEC was higher than 5F GEC (95.6% vs. 98.4%, p = 0.037). Pressure damping with 5F GEC occurred frequently than 5-4F GEC (7.4% vs. 2.5%, p < 0.05). Similarly, the incidence of intraoperative hypotension was higher in 5F GEC than 5-4F GEC (4.7% vs.1.9%, p < 0.05). CONCLUSIONS: The novel 5-4F tapered GEC was superior to the 5F GEC in facilitating successful completion of PCI in the majority of patients with complex lesions via transradial approach.


Assuntos
Calcinose , Intervenção Coronária Percutânea , Humanos , Masculino , Pessoa de Meia-Idade , Idoso , Feminino , Intervenção Coronária Percutânea/métodos , Estudos Retrospectivos , Angiografia Coronária/métodos , Resultado do Tratamento , Catéteres , Doença Crônica , Fatores de Risco
15.
Comput Ind Eng ; 176: 108914, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36569422

RESUMO

What comes along with the repeating and wide-range COVID-19 outbreak is the increasingly latent supply disruption risk encountered by global supply chains. Among many instruments to enhance supply chain resilience, backup production may be an appropriate choice, whereas how to induce the supplier backup becomes an obstacle. In this study, we investigate a supply chain in the context of the crisis-like new normal with supply disruption risk, wherein a manufacturer uses private demand information as a strategic lever, according to which a supplier decides whether to adopt backup production. Our findings reveal that the supplier's equilibrium decision on the adoption of backup production exhibits a cutoff structure when the manufacturer shares demand information. Moreover, we uncover the effect of information sharing on backup decision. In specific, information sharing impedes the adoption of backup production under low demand potential while promoting it under high demand potential. Interestingly, the manufacturer may have the incentive to share the demand information with the upstream supplier if the demand variability is low and the backup cost is moderate, and such information sharing stimulates the supplier to adopt the backup production. Counterintuitively, the manufacturer and the whole supply chain may display nonmonotonic relations to the backup cost as a result.

16.
Oral Maxillofac Surg ; 27(1): 117-124, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35072841

RESUMO

BACKGROUND: Intraoral soft tissue deficiency and impaired wound beds are common problems after cleft and tumour surgery or after dental trauma. Frequently, limited defects are overtreated with extensive microvascular reconstruction procedures, but pedicled flaps remain useful, as they are simple to harvest, and they provide a reliable outcome. The buccal flap, first described in the 1970s, has been used for palatine lengthening in cleft patients over decades. In the following, we present an expanded indication in cases of palatal fistula, complex vestibulum, exposed bone in orthognathic surgery, and osteoradionecrosis. METHODS: We conducted a retrospective chart review and report on all buccal flaps harvested in our department within the last 3 years with a follow-up period of at least half a year after flap surgery. Patients of all age groups and treatment indications in which a buccal flap was used were implicated in the evaluation. RESULTS: Sixteen buccal flaps were performed in 10 patients. The median age at the time of surgery was 42 years, reaching from 12 up to 66 years. Fourteen buccal flaps were used for upper jaw or palatal coverage; two buccal flaps were used in the mandible. In terms of complications (four flaps; 25%), there were two partial flap failures, one wound dehiscence and one wound dehiscence. There were no failures of the remaining mucosal flap islands after pedicle dissection. CONCLUSION: The buccal flap is a reliable and straightforward approach to challenging intraoral wound beds with soft tissue deficiency. We thoroughly discuss the additional indications for buccal flap surgery, describe the harvest technique, and provide strategies to prevent intra- and postoperative complications.


Assuntos
Procedimentos de Cirurgia Plástica , Humanos , Adulto , Estudos Retrospectivos , Retalhos Cirúrgicos/cirurgia , Retalhos Cirúrgicos/irrigação sanguínea , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Mandíbula/cirurgia
17.
Environ Sci Pollut Res Int ; 30(6): 15082-15101, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36168010

RESUMO

In this study, the effect of employing ZnO/Acalypha Indica leaf extract (ZAE) on the energy absorption of a coated portable solar cooker has been examined using an experimental setup. A prototypical model has been developed to corroborate in associating an investigative outcome per constituents of the experiments. The studied heat transfer process in ZAE is stable for harsh conditions. The design analysis and an estimation of the system performance were done given various parameters including the pressure of the vacuum envelope, bar plate coating digestion, emissivity, and solar rays. The fabricated solar was tested with and without ZAE to investigate the impact of this coating material on the solar cooker's thermal performance. To observe the performance of the new design, two figures of merit (F1 and F2) have been introduced. The factual food cooking assessments were for a family of four people, which operated in ZAE coating (0.8, 1.0, 1.2 µm) of the solar cooker. The values of F1 and F2 for the proposed cooker were obtained as 0.1520 and 0.4235, respectively, which is intact with the BIS values. The results revealed that employing ZAE instead of a thermal NHC-PV solar cooker reduced the time required to boil 2 L of water for about 47 min. The overall thermal energy productivity of the solar cooker with electrical backup was obtained as 42.65%, indicating that the ZAE coating can improve the thermal efficiency by 10.35%.


Assuntos
Acalypha , Energia Solar , Óxido de Zinco , Humanos , Culinária , Eletricidade , Extratos Vegetais
18.
Indian Dermatol Online J ; 13(3): 321-325, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36225997

RESUMO

Dermatology is a specialty that relies a lot on the visual aspect of clinical diagnosis. Taking photographs of skin lesions is a routine part of clinical practice. They are used to document skin changes during the course of treatment. It is useful for publishing articles in academic journals and textbooks, and serves as a teaching aid. Images are an important form of patient data. Like all patient data, the need for ensuring confidentiality and security is of paramount importance. Keeping all this in mind, it is important to know how to store, backup and archive your images in a safe and efficient manner.

19.
Am Nat ; 200(4): 486-505, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36150199

RESUMO

AbstractThe sexual ornamentation of animals typically consists of multiple distinct traits. The classical research approach focuses on differences among these traits, but this approach may often be misleading because of correlations among distinct sexual traits of similar origins. There are many published studies on the correlation structures of sexual traits, but the way receivers take into account the components of an integrated, multicomponent trait system remains mostly unknown. Here, we propose a general analytical framework to assess the possible sexual selection consequences of within-individual coherence in the expression of multiple correlated sexual traits. We then apply this framework to a long-term mutual plumage coloration data set from a wild bird population. The results suggest that the coherence of component plumage color traits is not sexually selected. However, component trait coherence affects sexual selection on integrated plumage color. When assessing across-spectrum plumage reflectance, receivers choosing mates apparently disregard a component trait if it is inconsistent with the overall expression of other components. This indicates that separately examining and manipulating distinct sexual traits may often be misleading. Theoretical and empirical studies should further explore the effects of coherence on the ornament-preference coevolution.


Assuntos
Plumas , Seleção Sexual , Animais , Pigmentação , Reprodução , Caracteres Sexuais , Comportamento Sexual Animal
20.
Entropy (Basel) ; 24(7)2022 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-35885114

RESUMO

The article discusses an online problem of routing and spectrum allocation with dedicated path protection in elastic optical networks. We propose three novel algorithms to solve this problem. The first of them is the minimum-cost-maximum-flow heuristic algorithm, which calculates the solution assuming that the spectrum units on the working and dedicated backup path are the same. Such an assumption, on the one hand, increases the bandwidth blocking probability; however, on the other hand, it enables a simple, cheap and fast way to connect customers to the network during the implementation phase of elastic optical networks. The next two algorithms, which determine the exact solutions, are based on the branch and bound method. The first calculates the working and dedicated backup paths with the minimum total occupied bandwidth, called the total cost, while the second calculates the paths with the minimum total length. These algorithms enable the performance evaluation of the proposed heuristic algorithm and provide the answer as to what should be optimized, the total cost or the total length of paths, in order to minimize the bandwidth blocking probability. Extensive simulation research has shown that the proposed heuristic algorithm can be used in elastic optical networks, but with a small network load. Moreover, it is shown that the optimization of the total cost of paths provides a slightly lower blocking probability than the optimization of the total length of paths.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA