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1.

Virtual organisations are non-conventional structures aiming at sharing the same goals, developing common practices or creating wealth in a collaborative manner. Accordingly, competence issues are important topics to be addressed in order to ensure coherence between the different objectives of entities taking part in a virtual organisation to guarantee an efficient use of available resources. This paper introduces the principles for modelling competence-based virtual organisations by using a uni?ed enterprise competence modelling language (UECML). Our proposed modelling approach is inspired from previous related works mainly in competence-based enterprise modelling. The language provides a neutral interface to virtual organisation modelling based on competences, taking into account the several roles and entities participating in a virtual organisation. Therefore, providing constructs covering processes, resources, competences, and virtual organisation (VO) entities. A case study of the Swiss virtual network Virtuelle Fabrik with regards to the project Abfallhai is presented and discussed, showing how the developed modelling language is adapted to model virtual organisations.  相似文献   

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This paper summarizes past efforts to use market-based approaches to reallocate resources during the design of space systems, and it proposes an extension to these previous efforts that would include the risk of system failure as a tradable resource. The proposed approach builds from the Cassini Resource Exchange, a method used to allow instrument developers for the Cassini space mission to trade resources among themselves over the life of the project. Market-based design methods offer potential for increased efficiency in engineering design, and small-scale field trials would be a logical step in further testing and improving these approaches.  相似文献   

4.
ABSTRACT

Reliability test plans are important for producing precise and accurate assessment of reliability characteristics. This article explores different strategies for choosing between possible inspection plans for interval-censored data given a fixed testing timeframe and budget. A new general cost structure is proposed for guiding precise quantification of total cost in inspection test plan. Multiple summaries of reliability are considered and compared as the criteria for choosing the best plans using an easily adaptable method. Different cost structures and representative true underlying reliability curves demonstrate how to assess different strategies given the logistical constraints and nature of the problem. Results show several general patterns exist across a wide variety of scenarios. Given the fixed total cost, plans that inspect more units with less frequency based on equally spaced time points are favored due to the ease of implementation and consistent good performance across a large number of case study scenarios. Plans with inspection times chosen based on equally spaced probabilities offer improved reliability estimates for the shape of the distribution, mean lifetime, and failure time for a small fraction of population only for applications with high infant mortality rates. This article uses a Monte Carlo simulation-based approach in addition to the commonly used approach based on the asymptotic variance and offers comparison and recommendation for different applications with different objectives. In addition, the article outlines a variety of different reliability metrics to use as criteria for optimization, presents a general method for evaluating different alternatives, as well as provides case study results for different common scenarios.  相似文献   

5.
BACKGROUND: A pilot study was conducted to learn whether an academic medical center's database of patient complaints would reveal particular service units (or clinics) with disproportionate shares of patient complaints, the types of complaints patients have about those units, and the types of personnel about whom the complaints were made. RESULTS: During the seven-year (December 1991-November 1998) study period, Office of Patient Affairs staff recorded 6,419 reports containing 15,631 individual complaints. More than 40% of the reports contained a single complaint. One-third of the reports contained three or more complaints. Complaints were associated with negative perceptions of care and treatment (29%), communication (22%), billing and payment (20%), humaneness of staff (13%), access to staff (9%), and cleanliness or safety of the environment (7%). Complaints were not evenly distributed across the medical center's various units, even when the data were corrected for numbers of patient visits to clinics or bed days in the hospital. The greatest proportion of complaints were associated with physicians. DISCUSSION: Complaint-based report cards may be used in interventions in which peers share the data with unit managers and seek to learn the nature of the problems, if any, that underlie the complaints. Such interventions should influence behavioral and systems changes in some units. SUMMARY AND CONCLUSIONS: Further experience should indicate how different types of complaints lead to different kinds of interventions and improvements in care. Tests of the system are also currently under way in several nonacademic community medical centers.  相似文献   

6.
This article attempts to show how computer graphics can assist in computerized development of project-type schedules as exemplified by preventive maintenance scheduling in the electric power industry. The method is equally applicable to the scheduling of maintenance activities in general or, with modification, to devising shift schedules for personnel such as police, nurses, and toll collectors who must provide 24-hour service with changing demand levels. A hand procedure currently used by electric utilities for creating preventive maintenance shutdown schedules for generator units is first described. A mixed integer programming model of the problem is given which is computationally intractable for any realistic-size problems. The same problem using man-machine interaction via a graphics terminal to overcome the computational limitations of the mathematical formulation is then described and illustrated. A proposed extension to improve the speed of solution is also described.  相似文献   

7.
Traditionally, international humanitarian organisations have used on-demand dispatch of disaster relief goods from regional logistics units (RLUs) for sudden onset disaster response. This paper investigates the improvements in efficiency and resilience of disaster relief operations by combining the existing method of onshore prepositioning of relief items in RLUs with offshore prepositioning of relief items on-board vessels and at seaport terminals. The problem is formulated as a linear programming model that incorporates different logistical costs, including inventory cost, replenishment cost, and transportation cost, to find the best combination of disaster relief methods. At the tactical level, the model determines how much and where disaster relief items need to be prepositioned. At the operational level, the model addresses how much and by which mode of transport the disaster relief items need to be transported to disaster points. The model is tested on 16 major disasters in Southeast Asia. The main finding is that offshore prepositioning can contribute to cost reduction and resilience without compromising on the speed or the scale of the response. The results also suggest that the benefits depend on the duration of the disaster emergency period and the ratio of offshore storage cost to onshore storage cost.  相似文献   

8.
We propose an interactive method for decision making under uncertainty, where uncertainty is related to the lack of understanding about consequences of actions. Such situations are typical, for example, in design problems, where a decision maker has to make a decision about a design at a certain moment of time even though the actual consequences of this decision can be possibly seen only many years later. To overcome the difficulty of predicting future events when no probabilities of events are available, our method utilizes groupings of objectives or scenarios to capture different types of future events. Each scenario is modeled as a multiobjective optimization problem to represent different and conflicting objectives associated with the scenarios. We utilize the interactive classification-based multiobjective optimization method NIMBUS for assessing the relative optimality of the current solution in different scenarios. This information can be utilized when considering the next step of the overall solution process. Decision making is performed by giving special attention to individual scenarios. We demonstrate our method with an example in portfolio optimization.  相似文献   

9.
Using annualised hours (i.e., distributing working hours irregularly over a year) grants a company the flexibility needed to meet the seasonal nature of demand. Since annualised hours can lead to a worsening of the staff's working conditions, many laws and collective bargaining agreements contain constraints that affect the distribution of working time. In the past few years, efforts have been made to develop methods for optimally solving planning problems involving annualised working hours. However, to our knowledge, the problem of replanning work time with annualised working hours has not been addressed in the literature. Herein, we explore different ways of achieving said replanning, using mixed-integer linear programming models. Two main objectives are considered: the cost of the new plan and the stability of the scheduling of workers’ working time. Solving the models for various scenarios yields the quantitative information that is needed to replan an annualised hours system.  相似文献   

10.
In India, approximately 58,000 radiation workers are monitored using locally made CaSO4:Dy teflon embedded thermoluminescence dosemeter (TLD) badge system. The automatic hot gas readers developed locally are also used in TL measurements. The hot gas reader system has many advantages over the manual readers used previously and has completely replaced the manual reader system in all TLD personnel monitoring units in India. In the present study, the new reader system is studied and a theoretical attempt has been made to interpret the experimentally obtained results. The glow curves are generated theoretically and are also plotted experimentally. It has been found that the heat capacity of the heating gas, which is responsible for the transfer of heat, has a role in deciding the position of peak and is verified experimentally using different gas flow rates of nitrogen and argon as heating gases in the reader. The theoretical study may also be helpful in fitting the experimentally obtained glow curves and, therefore, the elimination of unwanted non-radiation-induced contributions, such as dark current, electronic spikes, light leakage and triboluminescence that generally distort the glow curve shape, can be achieved.  相似文献   

11.
How will people respond to the discovery of extra-terrestrial life? Potentially useful resources for addressing this question include historical prototypes, disaster studies and survey research. Reactions will depend on the interplay of the characteristics of the newly found life, the unfolding of the discovery, the context and content of the message and human information processing as shaped by biology, culture and psychology. Pre-existing images of extra-terrestrials as god-like, demonic, or artificial will influence first impressions that may prove highly resistant to change. Most probably people will develop comprehensive images based on minimal information and assess extra-terrestrials in the same ways that they assess one another. Although it is easy to develop frightening scenarios, finding microbial life in our Solar System or intercepting a microwave transmission from many light years away are less likely to be met with adverse reactions such as fear and pandemonium than with positive reactions such as equanimity and delight.  相似文献   

12.
The effective utilization of limited resources within a large police department represents a major organizational goal. This paper describes a project executed and implemented within the Indianapolis Police Department to plan communications support effectively. By properly identifying the appropriate staff levels and scheduling personnel when needed, the communications department's performance improved.  相似文献   

13.
This paper shows the algorithm implementation for a field-programmable gate array (FPGA)-based design for people counting using a low-level head-detection method. The hardware (HW) implementation on an FPGA allows the capture and online processing in real time on the same chip. Different annular patterns are used to process in parallel the image and detect heads of different sizes. Preprocessing and edge extraction are also made using reconfigurable HW. The developed system exploits HW processing, as the vision algorithm has been modified and tuned for HW implementation. It uses minimal area resources of a Spartan3 (1.5 Mgates), and its real-time performance is comparable with more sophisticated algorithms while utilizing very low cost circuits.   相似文献   

14.
In consulting services, call centres serve several types of customers. The demand of different customers who ask for specific skills hinders the ability to balance the workload among servers; thus, task reallocation may be needed. In this paper, we model a call centre with multi-type customers as a multi-class tandem queue and examine how to reallocate the workload among servers. To evaluate the performance of the system, we propose an approximate analytical method based on the aggregation of Markov chain models. To optimally reallocate the workload, we propose a search algorithm based on the optimal computing budget allocation method. A simulation is employed to validate the analytical method and identify regions in which it can be successfully applied. A case study shows the applicability of the approach and quantifies its benefits in a realistic situation.  相似文献   

15.
INTRODUCTION: Non-fatal road casualties are under-reported, with official figures coming from the police. In the French Rh?ne county, a road trauma registry constitutes a second source of reporting but its completeness needs to be assessed. We also wish to estimate an incidence rate of non-fatal road casualties that is corrected for under-count. METHODS: Having two sources of reporting available, we can apply the capture-recapture method under certain conditions. To take into account different reporting probabilities among casualties, the capture-recapture analysis is stratified according to injury severity (New Injury Severity Score=NISS), road user type and human third party. To evaluate the sensitivity of the capture-recapture estimate on the number of matched casualties between the police file and the registry, three scenarios of record-linkage are considered. RESULTS: For serious (NISS 9+) non-fatal road casualties, the police ascertainment rate is at most 57%, the registry ascertainment rate is at most 87%, and the aggregate ascertainment rate is at most 95%. The ascertainment-corrected incidence rate for serious (NISS 9+) non-fatal road casualties is at least 65 per 100,000. CONCLUSION: The degree of completeness of the registry for serious casualties is rather high, though not satisfactory.  相似文献   

16.
Yield is one of the most important measures of manufacturing performance in the semiconductor industry, and equipment condition plays a critical role in determining yield. Researchers and practitioners alike have traditionally treated the problems of equipment maintenance scheduling and production dispatching independently, ignoring how equipment condition may affect different product types or families in different ways. This paper addresses the problem of how to schedule maintenance and production for a multiple-product, multiple-stage production system. The problem is based on the situation found in semiconductor wafer fabrication where the equipment condition deteriorates over time, and this condition affects the yield of the production process. We extend a recently developed Markov decision process model of a single-stage system to account for the fact that semiconductor wafers have multiple layers and thus make repeated visits to each workstation. We then propose a methodology by which the single-stage results can be applied in a multi-stage system. Using a simulation model of a four-station wafer fab, we test the policies generated by the model against a variety of other maintenance and dispatching policy combinations. The results indicate that our method provides substantial improvements over traditional methods and performs better as the diversity of the product set increases. In the scenarios examined, the reward earned using the policies from the combined production and maintenance scheduling method was an average of more than 70° higher than the reward earned using other policy combinations such as a fixed-state maintenance policy and a first-come, first-serve dispatching policy.  相似文献   

17.
Significant progress has been made in reducing the risk from exposure to radon and its progeny all over the world as a result of efforts made by different organisations which are working together to educate public about the harmful effects of radon. During the past several surveys, it was found that uneducated people were totally ignorant of radon in Pakistan. Even a large number of science graduates knew very little about radon and its hazards. Therefore, a nationwide survey was conducted to measure general awareness and factual knowledge about radon and its health hazards. In this regard, a questionnaire was prepared and distributed among different classes of the society including students, government employees and general public throughout the country. A total of 7000 people with different educational backgrounds participated in this survey, which includes uneducated people (1000), science and humanities graduates (2000 each) and under graduate (2000). Statistical analysis, excluding uneducated people, revealed that 30.4% of the total respondents were aware of radon and 69.6% had even not heard of radon. Only approximately 8.4% of the total respondents were knowledgeably aware of radon.  相似文献   

18.
Data envelopment analysis (DEA) is a non-parametric method for measuring the relative efficiency of a set of decision making units using multiple precise inputs to produce multiple precise outputs. Several extensions to DEA have been made for the case of imprecise data, as well as to improve the robustness of the assessment for these cases. Prevailing robust DEA (RDEA) models are based on mirrored interval DEA models, including two distinct production possibility sets (PPS). However, this approach renders the distance measures incommensurate and violates the standard assumptions for the interpretation of distance measures as efficiency scores. We propose a modified RDEA (MRDEA) model with a unified PPS to overcome the present problem in RDEA. Based on a flexible formulation for the number of variables perturbed, MRDEA calculates the empirical distribution for the interval efficiency for the case of a random number of variables affected. The MRDEA approach also decreases the computational complexity of the RDEA model, as well as significantly increases the discriminatory power of the model without additional information requirements. The properties of the method are demonstrated for four different numerical instances.  相似文献   

19.
Numerous space missions are planned by government agencies and private companies, with objectives including scientific research, prospecting for and mining resources, and establishing human settlements. These projects have potential to affect the extraterrestrial environment. Environmental impact assessment (EIA) is an important tool for assessing the potential impact of projects on Earth’s environment. However, the legal requirements to undertake EIA for extraterrestrial projects are limited and most EIAs that have been conducted have not considered impacts beyond Earth’s atmosphere. Technical barriers to extraterrestrial EIA also need to be overcome, including a lack of guidelines and methodologies. This paper addresses the latter issue by identifying the extraterrestrial impacts that may arise from space projects and relating them to the environmental topic areas in the European EIA Directive. An example is then provided of how EIA screening and scoping can be undertaken for the extraterrestrial elements of space projects, using six scenarios. Effective EIA screening and scoping is key to deciding whether EIA is required and if so which topic areas should be included.  相似文献   

20.
In designing a structure for a given purpose, the designer should aim at the most economical design from many points of view. Minimum weight designs may not be the most economical ones. Nevertheless, such designs provide insights into other types of design and may pave ways for improvements in design procedures. Minimum weight designs of continuum structures may be formulated as numerical optimization problems using either the finite difference method or the finite element method, and the resulting minimization problem may be solved using techniques of numerical optimization. This paper, on the other hand, considers the formulation of the minimum weight design of a spherical cap as a dynamic programming problem and its solution. The paper also discusses the advantages and limitations of the approach.  相似文献   

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