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Compared to the three-dimensional (3D) perovskite materials, the Ruddlesden−Popper (R-P) type two-dimensional (2D) organic-inorganic metal halide perovskites have indicated specific unique physical properties that include moisture-stable behaviours, exciton effects, and quantum confinements, making it a solid and potential candidate for optoelectronic applications. Nonetheless, while specific candidates have exhibited visible-blind ultraviolet (UV) photoelectric response, most R-P type 2D materials have been known to be photosensitive to visible light. In this study, an R-P type 2D lead bromide hybrid perovskite (C8H11FN)2PbBr4, (1, where C8H10FN is 4-Fluorophenethylamine) has been analyzed, which contained both inorganic frameworks and organic cations. Moreover, 1 exhibits a relatively wide optical bandgap of 3.30 eV, corresponding to that of the Br-based 2D R-P perovskites expected to exhibit selective photoresponse for the UV light. It is pertinent to note that the photodetectors based on the crystal of 1 exhibit spectral selective photoresponse for UV light with high detectivity up to ∼ 1.6×1011 Jones. Moreover, the trap density of 1 is estimated to be 1.34×1011 cm-3; the trap density of 1 was almost equal to that obtained in the high-quality 3D CH3NH3PbBr3 single crystals. Besides, under external environment, 1 illustrated excellent stability. The figures of merit for its photoconductivity make 1 a potential candidate for the visible-blind UV photodetection. This discovery opens up new vistas for the further development of optoelectric devices based on 2D R-P organic-inorganic hybrid perovskites.

The elevated intraocular pressure (IOP) is one of the important risk factors of glaucomatous optic nerve damage. The deformations of glaucomatous optic nerve head (ONH) due to the elevated IOP might lead to further damage to the optic nerve. The ONH deformations due to the elevated IOP depend on their geometry. Therefore, it is meaningful to investigate the relationship between geometrical parameters and the deformation of ONH. Firstly, the geometrical parameters of ONH were obtained by in vivo using spectral domain optical coherence tomography. Then, individual-specific three-dimensional (3D) models of ONH for glaucoma and normal subjects were established and the deformations of ONH were acquired by using finite element method. Furthermore, the thickness changes of retina and lamina cribrosa were calculated under different IOPs. Finally, correlations between geometrical parameters and the relative deformations of the human ONH were researched by using Spearman correlation. It was found that the relative thickness change of patient’s retina was larger than that of normal subjects under the same condition. The correlation of several parameters, including cup area, and lamina cribrosa depth, with relative deformations of ONH had statistical significance.

The metadata IO plays a critical role in achieving the high IO scalability and throughput to file systems. Due to the resource contention, the performance of the metadata IO is low. Adding the SSD into the storage system is a effective way to improve the performance of file systems, but the current methods mainly focus on the performance of the data server, rarely aim to the performance of the metadata IO. In this paper, we proposed a novel cooperative caching management algorithm based on DRAM and SSD named ACSH. By exploiting the temporal locality widely exhibited in most of the metadata workloads, ACSH can improve the performance of the metadata IO with reducing the write traffic to the SSD, and it includes a adaptive adjustment model, which can adjust the number of the cached metadata according to the locality strength of the metadata workload for improving the perforamcne and reducing the write traffic to the SSD cache layer further. ACSH has been evaluated based on the real-world workloads. Our experiments show that ACSH can reduce the latency by upi¾źto 1.5---3X in contrast with the original cache consisting of DRAM which has the same cost with ACSH. Compared with the recent study LARC, it can reduce the write traffic to the SSD by upi¾źto 23---30i¾ź%.

With the expansion of the Internet, Trust has attracted the attention of more and more researchers. This paper focuses on the trust transitivity problem and proposes a trust transitivity model based on Dempster-Shafer Theory. In our model, we show two types of trust relationship: Identity Trust and Behavior Trust based on Directness Trust and Recommendation Trust. Then we build the trust transitivity network and propose the trustworthiness propagation and combination rules. Finally, we propose a method for transforming the triple of evidence theory to a simple result in order to select the trust entity easily. W e also use the nearness degree to analyze the transitivity rationality and show how to use the trust transitivity model by a shopping scenario in TaoBao and illustrate its legitimacy

Both criterion values and user’s preference of criterion should be taken into account when selecting web services with same functionalities. Usually, user describes his/her preference of criterion using qualitative concept. But the quantitative value corresponding to qualitative concept is uncertain. Thus, the subjective weight acquired based on user's preference is uncertain. This paper provides a method to select web service using uncertain subjective weight. Firstly, we present two ways of calculating subjective weight; Normalization and Least square method. The subjective weight is described using cloud model. Secondly, the criterion values of each web service are synthesized using marginal substitution method with indifference curve of Cobb-Douglas preferences. Thirdly, an algorithm for service selection is presented. Using this scheme, an experiment is conducted on selecting weather forecast web service. The result of the experiment is validated by the sensibility analysis of weight.

In Service-Oriented Computing (SOC), personalized requirements from diverse user present challenges to develop software with lower cost and high degree of satisfaction. Due to the popularity and fundamentality of Web services (WS), WS-based software is born through SOC by dynamically linking and customizing Web Services resources in the Internet to meet users’ goals. This paper proposes a goal-driven approach for customizing WS-based software to satisfy diversity of users’ requirements. More specifically, a unified and service-oriented framework for requirements metamodeling is adopted to construct well-organized and interrelated domain assets as the basis for customization; and a goal-driven customization method for WS-based software is designed to support implementation of this approach. This is followed by a case study in the urban transportation domain that demonstrates in detail the feasibility of our approach.

For E-commerce, such as online trade and interactions on the Internet are on the rise, a key issue is how to use simple and effective evaluation methods to accomplish trust decision-making for customers. It is well known subjective trust holds uncertainty like randomness and fuzziness. However, existing approaches commonly based on probability or fuzzy set theory cannot attach enough importance to uncertainty. To remedy this problem, a new quantificational subjective trust evaluation approach is proposed based on the cloud model. The subjective trust may be modeled with cloud model, and expected value and hyper-entropy of subjective cloud is used to evaluate the reputation of trust objects. Our experimental data shows that the method can effectively support subjective trust decision, which provides a helpful exploitation for the subjective trust evaluation.

The increasing size and complexity combined with short development cycles for web-based applications has led to the term web crisis whereby undisciplined development techniques work to keep up with user needs. Therefore, defining and measuring the quality of web-based applications has emerged as a compelling area of exploration. By first examining the difference between conventional software applications and web-based software applications, this paper examines why methods used for measuring the quality of conventional software applications now have less applicability and provides a rationale for new factors to define quality for web-based software applications. Further research is proposed for measurement of these factors.

As online trade and interactions on the internet are on the rise, a key issue is how to use simple and effective evaluation methods to accomplish trust decision-making for customers. It is well known that subjective trust holds uncertainty like randomness and fuzziness. However, existing approaches which are commonly based on probability or fuzzy set theory can not attach enough importance to uncertainty. To remedy this problem, a new quantifiable subjective trust evaluation approach is proposed based on the cloud model. Subjective trust is modeled with cloud model in the evaluation approach, and expected value and hyper-entropy of the subjective cloud is used to evaluate the reputation of trust objects. Our experimental data shows that the method can effectively support subjective trust decisions and provide a helpful exploitation for subjective trust evaluation.

Quality of Web service, especially the reputation, has become a benchmark to differentiate the services and providers. Unfortunately, the current reputation research in the field of Web services don't reasonably and correctly think about the randomicity and fuzziness which has been the basic issue in the relative research area about trust. We proposed two novel metrics to qualify the reputation of Web services and providers. We designed two kinds of trust model based on cloud model theory to describe the randomicity and fuzziness of the two metrics. Furthermore, a formalized calculation was provided to obtain the trust degree of services requestors to Web services and providers.