928 resultados para Priority Queueing Disciplines
Resumo:
Optical networks provide a new dimension to meet the demands of exponentially growing traffic. Optical packet switching requires a good switch architecture, which eliminates the O/E/O conversion as much as possible. Wavelength Division Multiplexing (WDM) provides a breakthrough to exploit the huge bandwidth of the optical fiber. Different applications have different requirements, which necessitate employing differentiated services. This paper presents the idea of a priority-based λ-scheduler, where the packets are differentiated into different classes and services are provided accordingly. For example, class 0 can correspond to non real time applications like email and ftp, while class 1 can correspond to real-time audio and video communications. The architecture is based on that of the λ-scheduler and hence it has the added advantage of reduced component cost by using WDM internally.
Resumo:
Current studies indicate a need to integrate environmental management with manufacturing strategy, including topics like cross-functional integration, environmental impact, and waste reduction. Nevertheless, such studies are relatively rare, existing still a need for research in specific regional contexts. At the same time, the results found are not unanimous. Due to these gaps, the objective of this article is to analyze if environmental management can be considered a new competitive priority for manufacturing enterprises located in Brazil. A cross-sectional survey was conducted with Brazilian companies certified by ISO 14001. Sixty-five valid questionnaires were analyzed through Structural Equation Modelling (SEM). The first conclusion is that environmental management presents a preventive approach in the sample analyzed, focused on eco-efficiency, what potentially do not to create a competitive advantage. This preventive approach inhibits environmental management from being regarded as a new competitive manufacturing priority, in the full sense as defined by the literature. Another important result is that environmental management, although following a preventive focus, may influence positively the four manufacturing priorities: cost, quality, flexibility and delivery. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
[EN] The presence of emerging contaminants has been previously described in reclaimed water and groundwater of Gran Canaria (Spain). Despite of the environmental risk associated to irrigation with reclaimed water (R), this practice is necessary considering sustainability of the hydrological cycle in semiarid zones, especially regarding agricultural activity. The aim of this study was: i) to analyse the evolution during two years of contaminants of emerging concern, priority substances (2008/105/EC) and heavy metals in reclaimed water (R) and in a volcanic aquifer in the NE of Gran Canaria where a golf course has been irrigated with R since 1976 and ii) to relate this presence with physicochemical water properties and hydrogeological media. Reclaimed water and groundwater (GW) were monitoring quarterly from July 2009 to September 2011. Sorption and degradation processes in soil account for more compounds being detected in R. Diazinon and chlorfenvinphos were detected always in R and terbuthylazine, terbutryn and diuron at 90% of frequency. Considering all the samples, the most frequent compounds were chlorpyrifos ethyl, fluorene, phenanthrene and pyrene. Although their concentrations were frequently below 50 ngL-1, some contaminants, were occasionally detected at higher concentrations. Chlorpyrifos ethyl and diuron are priority substances detected frequently and at high concentrations so they must be included in monitoring studies. Geology and location seem to be related to the emerging compounds presence due to occasional contamination events (not related to R irrigation) and therefore not to an existence of a dangerous diffuse contamination level. Thus, it is preferable to select wells with less stable chemical water quality, in order to monitor the risk of emerging compounds presence. Considering the relationship between contaminant presence, chemical water quality, seasonal variation, hydrogeological characteristics and wells location we can conclude that chlorpyrifos ethyl and diuron were the most dangerous priority substances in terms of GW quality so they must be included in all of the monitoring studies, at least in Canary Islands.
Resumo:
The importance of organizational issues to assess the success of international development project has not been fully considered yet. After a brief overview, in 1st chapter, on main actors involved on international cooperation, in the 2nd chapter an analysis of the literature on the project success definition, focused on the success criteria and success factors, was carried out by surveying the contribution of different authors and approaches. Traditionally projects were perceived as successful when they met time, budget and performance goals, assuming a basic similarity among projects (universalistic approach). However, starting from a non-universalistic approach, the importance of organization’s effectiveness, in terms of Relations Sustainability, emerged as a dimension able to define and assess a project success. The identification of the factors influencing the relationship between and inside the organizations becomes consequently a priority. In 3th chapter, starting from a literature survey, the different analytical approaches related to the inter and intra-organization relationships are analysed. They involve two different groups: the first includes studies focused on the type of organizations relationship structure (Supply Chains, Networks, Clusters and Industrial Districts); the second group includes approaches related to the general theories on firms relationship interpretation (Transaction Costs Economics, Resource Based View, Organization Theory). The variables and logical frameworks provided by these different theoretical contributions are compared and classified in order to find out possible connections and/or juxtapositions. Being an exhaustive collection of the literature on the subject is impossible, the main goal is to underline the existence of potentially overlapping and/or integrating approaches examining the contribution provided by different representative authors. The survey showed first of all many variables in common between approaches coming from different disciplines; furthermore the non overlapping variables can be integrated contributing to a broader picture of the variables influencing the organization relations; in particular a theoretical design for the identification of connections between the inter and the intra-organizations relations was made possible. The results obtained in 3th chapter help to defining a general theoretical framework linking the different interpretative variables. Based on extensive research contributions on the factors influencing the relations between organizations, the 4th chapter expands the analysis of the influence of variables like Human Resource Management, Organizational Climate, Psychological Contract and KSA (Knowledge, Skills, Abilities) on the relation sustainability. A detailed analysis of these relations is provided and a research hypothesis are built. According to this new framework in 5th chapter a statistical analysis was performed to qualify and quantify the influence of Organizational Climate on the Relations Sustainability. To this end the Structural Equation Modeling (SEMs) has adopted as method for the definition of the latent variables and the measure of their relations. The results obtained are satisfactory. An effective strategy to motivate the respondents to participate in the survey seems to be at the moment one of the major obstacles to the analysis implementation since the organizational performances are not specifically required by the projects’ evaluation guidelines and they represent an increase in the project related transaction costs. Their explicit introduction in the project presentation guidelines should be explored as an opportunity to increase the chances of success of these projects.
Resumo:
This project was stimulated by the unprecedented speed and scope of changes in Bulgarian higher education since 1989. The rapid growth of the student population and the emergence of a new private sector in higher education led to tightening governmental control and a growing criticism of autonomy and academic freedom. This raised questions about the need for diversification in the field, about the importance of recent innovations in terms of strategic choices for future development and so of how higher education governance could maintain diversity without the system deteriorating. The group first traced the extent of spontaneous processes of innovation at the level of content, of institutions, and the organisation of teaching and learning processes. They then identified the different parties in the struggle for institutionalisation and against diversification, and promising mechanisms for maintaining diversity in higher education. On this basis they outlined a basis for a wide-ranging public discussion of the issue which may serve as a corrective to the mechanisms of state control. Their work included analysis of the legislative framework laid down in the Higher Education Act, which effectively dispenses with the autonomy of universities. They then surveyed the views of both high-level executives in the field and the academics actually involved in the process, as well as of the "consumers" of the educational product, i.e. the students. In considering diversification, they focused on four different types of programmes, including those where diversification is largely limited to content level (e.g. Law), those where it operates mainly on structural levels (e.g. Industrial Management), those where it is often feigned (e.g. Social Work), and those where it is at best formal and sporadic (e.g. Mechanical Engineering). They conclude that the educational system in Bulgaria has considerable internal resources for development. The greatest need is for adequate statutory regulation of academic life which will provide incentives for responsible academic development of higher education institutions and create conditions for the institutionalisation of academic self-organisation and self-control, which will in turn limit the pathological trends in the diversification processes.
Resumo:
OBJECTIVES: To compare the clinical outcomes of standard, cylindrical, screw-shaped to novel tapered, transmucosal (Straumann Dental implants immediately placed into extraction sockets. Material and methods: In this randomized-controlled clinical trial, outcomes were evaluated over a 3-year observation period. This report deals with the need for bone augmentation, healing events, implant stability and patient-centred outcomes up to 3 months only. Nine centres contributed a total of 208 immediate implant placements. All surgical and post-surgical procedures and the evaluation parameters were discussed with representatives of all centres during a calibration meeting. Following careful luxation of the designated tooth, allocation of the devices was randomly performed by a central study registrar. The allocated SLA titanium implant was installed at the bottom or in the palatal wall of the extraction socket until primary stability was reached. If the extraction socket was >or=1 mm larger than the implant, guided bone regeneration was performed simultaneously (Bio Oss and BioGide. The flaps were then sutured. During non-submerged transmucosal healing, everything was done to prevent infection. At surgery, the need for augmentation and the degree of wound closure was verified. Implant stability was assessed clinically and by means of resonance frequency analysis (RFA) at surgery and after 3 months. Wound healing was evaluated after 1, 2, 6 and 12 weeks post-operatively. RESULTS: The demographic data did not show any differences between the patients receiving either standard cylindrical or tapered implants. All implants yielded uneventful healing with 15% wound dehiscences after 1 week. After 2 weeks, 93%, after 6 weeks 96%, and after 12 weeks 100% of the flaps were closed. Ninety percent of both implant designs required bone augmentation. Immediately after implantation, RFA values were 55.8 and 56.7 and at 3 months 59.4 and 61.1 for cylindrical and tapered implants, respectively. Patient-centred outcomes did not differ between the two implant designs. However, a clear preference of the surgeon's perception for the appropriateness of the novel-tapered implant was evident. CONCLUSIONS: This RCT has demonstrated that tapered or standard cylindrical implants yielded clinically equivalent short-term outcomes after immediate implant placement into the extraction socket.
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To what extent is “software engineering” really “engineering” as this term is commonly understood? A hallmark of the products of the traditional engineering disciplines is trustworthiness based on dependability. But in his keynote presentation at ICSE 2006 Barry Boehm pointed out that individuals’, systems’, and peoples’ dependency on software is becoming increasingly critical, yet that dependability is generally not the top priority for software intensive system producers. Continuing in an uncharacteristic pessimistic vein, Professor Boehm said that this situation will likely continue until a major software-induced system catastrophe similar in impact to the 9/11 World Trade Center catastrophe stimulates action toward establishing accountability for software dependability. He predicts that it is highly likely that such a software-induced catastrophe will occur between now and 2025. It is widely understood that software, i.e., computer programs, are intrinsically different from traditionally engineered products, but in one aspect they are identical: the extent to which the well-being of individuals, organizations, and society in general increasingly depend on software. As wardens of the future through our mentoring of the next generation of software developers, we believe that it is our responsibility to at least address Professor Boehm’s predicted catastrophe. Traditional engineering has, and continually addresses its social responsibility through the evolution of the education, practice, and professional certification/licensing of professional engineers. To be included in the fraternity of professional engineers, software engineering must do the same. To get a rough idea of where software engineering currently stands on some of these issues we conducted two surveys. Our main survey was sent to software engineering academics in the U.S., Canada, and Australia. Among other items it sought detail information on their software engineering programs. Our auxiliary survey was sent to U.S. engineering institutions to get some idea about how software engineering programs compared with those in established engineering disciplines of Civil, Electrical, and Mechanical Engineering. Summaries of our findings can be found in the last two sections of our paper.