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排序方式: 共有204条查询结果,搜索用时 15 毫秒
1.
J.H. Trienekens P.M. WognumA.J.M. Beulens J.G.A.J. van der Vorst 《Advanced Engineering Informatics》2012,26(1):55-65
Food supply chains are increasingly complex and dynamic due to (i) increasing product proliferation to serve ever diversifying and globalising markets as a form of mass customisation with resulting global flows of raw materials, ingredients and products, and (ii) the need to satisfy changing and variable consumer and governmental demands with respect to food safety, animal welfare, and environmental impact. Transparency in the food supply chain is essential to guarantee food quality and provenance to all users of food and food products. Intensified information exchange and integrated information systems involving all chain actors are needed to achieve transparency with respect to a multitude of food properties.In this paper, specific challenges of food supply chains are highlighted. Major elements are addressed that support transparency to consumers, the government and food companies, which are considered the claimants of transparency. Elements considered to be enablers of transparency are governance mechanisms, quality and safety standards and information exchange. The paper specifies these transparency claimants and enablers for food supply chains and identifies major information system functions and information technology applications needed to comply with transparency demands. It thereby provides a framework for transparency analysis in food supply chains. 相似文献
2.
3D geological models commonly built to manage natural resources are much affected by uncertainty because most of the subsurface is inaccessible to direct observation. Appropriate ways to intuitively visualize uncertainties are therefore critical to draw appropriate decisions. However, empirical assessments of uncertainty visualization for decision making are currently limited to 2D map data, while most geological entities are either surfaces embedded in a 3D space or volumes.This paper first reviews a typical example of decision making under uncertainty, where uncertainty visualization methods can actually make a difference. This issue is illustrated on a real Middle East oil and gas reservoir, looking for the optimal location of a new appraisal well. In a second step, we propose a user study that goes beyond traditional 2D map data, using 2.5D pressure data for the purposes of well design. Our experiments study the quality of adjacent versus coincident representations of spatial uncertainty as compared to the presentation of data without uncertainty; the representations' quality is assessed in terms of decision accuracy. Our study was conducted within a group of 123 graduate students specialized in geology. 相似文献
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A chitosan-based carbon dioxide (CO2) indicator was developed to monitor freshness or quality of packaged foods during their storage, as elevated CO2 levels inside a package is one of the prime indicators of microbial spoilage of food. The objective of this proof-of-concept study, therefore, was to develop a chitosan-based CO2 indicator and to investigate its performance in different operating environments. For the enhancement of signal strength of indicator, 2-amino-2-methyl-1-propanol (AMP) was used as an additive to the chitosan solution. Aqueous chitosan–AMP suspensions were prepared by addition of chitosan (0.1%, 0.2% and 0.4%) and AMP (0%, 5%, 10% and 20%) to distilled water at pH 7.0. Thereafter, the aqueous chitosan suspensions were incubated under 100% and 20% CO2 test atmospheres. The aqueous solubility of chitosan, which in turn impacts the degree of transparency of the suspension, was tested at different pHs and time intervals, spectrometrically. The transparency of 0.2% chitosan aqueous suspension increased dramatically below pH 6.5 under 20% or 100% CO2 incubation. The addition of a 5% AMP concentration to the chitosan suspension was found optimal for maximum CO2 absorption and this, therefore, increased transparency by more than 90%. 相似文献
5.
提出了一个含多个脱线TTP的公平的不可否认协议。与以前的不可否认协议相比,其特点是把一个TTP的任务分散到t个TTP,减少了对一个TTP的依赖,还可以检测出不诚实的TTP,并且实现了TTP的透明性。 相似文献
6.
We conduct both simulation and experiment studies of impacts of simultaneously varying the thicknesses of transparent bottom electrodes and semi-transparent top thin metal electrodes on optical characteristics (e.g., transmission, reflection) and efficiencies of transparent organic light-emitting devices (OLEDs). For the thickness range of both electrodes studied, the total electroluminescent (EL) efficiencies (including both bottom and top emission), EL spectra, and emission patterns remain similar; yet the ratio of top to bottom emission would be modulated by the semi-transparent top metal electrode thickness. The thickness of the transparent bottom electrode has weak effects on the efficiencies of top/bottom/total emission, but it does have definite effects on optical transmission/reflection spectra (e.g. peak/valley wavelengths). Meanwhile, the thickness of semi-transparent top metal electrodes mainly affect magnitudes of the optical transmission/reflection. Transmissive/reflective hues and appearances of the transparent OLEDs can thus be tuned by the thicknesses of bottom/top electrodes. Overall, we demonstrated efficient transparent green phosphorescent OLEDs exhibiting a high peak transmittance of up to 81% and rather high total external quantum efficiencies of up to 21–21.5% (corresponding to a total current efficiency of 80–82 cd/A and total power efficiency of 95–99 l m/W), among the highest (if not the highest) for planar transparent OLEDs using no other optical out-coupling structures. By varying the thicknesses of transparent bottom electrodes and semi-transparent top metal electrodes, the ratio of top to bottom emission, and the transmissive or reflective hues/appearances of transparent OLEDs in the off state can be tuned, yet without sacrificing total EL efficiencies or changing their EL colors/patterns. Such tunable optical characteristics of transparent OLEDs may find some interesting applications. 相似文献
7.
半导体光放大器以其良好的非线性在全光网络中具有广泛应用,但较长的载流子恢复时间一直是制约其用于超快全光信号处理的速率瓶颈,基于包含自发辐射噪声的半导体光放大器模型,探讨了提高半导体光放大器增益恢复时间的有效途径,通过对制约透明波长移动,增益饱和与有效载流子寿命的相关因素进行数值分析,得出以下结论:与单辅助光相比,采用双辅助光可以在不牺牲信号增益的前提下进一步缩短载流子寿命,因而是提高半导体光放大器增益恢复时间的有效途径,这一点对工程设计和应用具有一定的指导意义. 相似文献
8.
Olivera Marjanovic Dubravka Cecez-Kecmanovic 《The Journal of Strategic Information Systems》2017,26(3):210-232
Government agencies worldwide continue their commitment to providing open data in order to increase transparency of education, healthcare and other public services. Focusing on open government information systems (IS) that provide performance-related data, this paper explores the ongoing tension between government’s goal of transparency and the resulting largely opaque datification effects. Our research insights are derived from an empirical longitudinal study of a controversial open government IS called My School, currently providing performance data on almost 10,000 schools in Australia. We investigate the tension between transparency intended with schools’ open performance data and datification effects they create within the education system and a broader society, through the theoretical lens of Complex Adaptive Systems (CAS). Our study reveals how the tension emerges due to unpredictable use, propagation and reinterpretation of open data by more and more users. Consequently, the original meaning of data gets distorted, as these users continue to reconstruct and reinterpret ‘data’ in their own contexts and adapt their behavior in pursuit of their strategic goals. We also identify and theorize seven datification patterns underlying the tension and the ways they produce various social consequences. Based on these research contributions we discuss important strategic implications for government decision makers and identify new opportunities for future research on open government IS. 相似文献
9.
The novel technique of plasma chemical vapor deposition without using vacuum chamber was investigated to deposit SiOx films on polymeric substrates through tetraethoxysilane (TEOS)/Air atmospheric-pressure plasma (APP) glow discharge. Depending on the proper deposition parameters, thin and smooth SiOx films on polycarbonate substrates were prepared. The atmospheric-pressure plasma deposited SiOx films obtained the desirable transparency in the visible and increased absorption in UV region. The surface characteristics of APP deposited SiOx films were examined by various surface analysis methods including FTIR, XPS, and SEM. It is shown that SiOx films exhibited low porosity and admirable hardness for optical applications. 相似文献
10.
Tony Carr Author Vitae Andrew Morrison Author Vitae Author Vitae Andrew Deacon Author Vitae 《Computers and Composition》2007,24(3):266-284
Wikis represent flexible tools functioning as open-ended environments for collaboration while also offering process and group writing support. Here we focus on a project to innovate the use of wikis for collaborative writing within student groups in a final-year undergraduate political science course. The primary questions guiding our research were in what ways could wikis assist collaborative learning in an undergraduate course in political science and how we could support educators’ in the effective use of wikis? Curiously, wikis may serve as a mediating artifact for collaborative writing even among students who are reluctant to post online drafts. The paper raises questions concerning the nature and limits of lecturer and tutor power to deliver transformative educational innovations in relation to the capacity of students to embrace, comply with, or resist such innovation. In analysing the negotiation of the use of wikis in the course by and among the lecturer, tutors, and students, we draw on two principles in activity theory, which Yrjö Engeström argued are central to his model of expansive learning: multi-voicedness and contradictions [Engeström, Yrjö. (1987). Learning by expanding: An activity-theoretical approach to developmental research. Helsinki: Orienta-Konsultit; Engeström, Yrjö. (2001). Expansive learning at work: Toward an activity theoretical reconceptualization. Journal of Education and Work14(1), 133-156.]. We add a third principle, transparency, to more fully capture what we observed. 相似文献