Cold-lamination-bending of glass: Sinusoidal is better than circular

Cold-lamination-bending (CLB) of glass consists, first, in constraining the unbonded glass-interlayer package in the desired curved shape and, second, in performing the lamination process in autoclave. Releasing the laminate, the curvature is only partially maintained through the interlayer bond, due to an initial spring-back followed by the relaxation of the polymeric interlayer. Here, the whole process of single-curvature CLB, including the phase of release and the consequent contact problem with the constraining mould, is analyzed using sandwich beam theory. Comparisons are made between “stiff” interlayers (like Ionoplastic Polymers) and “soft” interlayers (like PVB). The time-dependent redistribution of stresses due to the interlayer viscosity is found for any assigned initial shape of the mould. Remarkably, the constant-curvature shape, indeed the most used, provokes shear stress concentrations in the interlayer with consequent risks of delamination. The sinusoidal shape, which for typical values of the deformation inappreciably differs from the circular one, provides a much smoother distribution of the shear stresses. A properly-designed gradual release of the laminated glass from the mould can substantially contribute to mitigate the peak stresses.     

面向事务处理的容错计算机系统结构设计与实现

提出了一种面向事务处理的容错计算机体系结构,设计了基于三模冗余的仲裁器和仲裁算法。在集群中,利用中心结点故障检测机制,采用仲裁器得到了一个逻辑上高可靠的管理态结点,通过该结点可以实现系统快速故障诊断和故障恢复。实验结果表明：节点间故障检测时间小于2s,故障节点切换时间小于5s,该系统的故障检测、故障节点切换可以满足事务处理系统对可靠性的要求。     

采用阈值法的自动血压计

提出收缩压和舒张压的判定采用阀值法,能使自动血压计不仅测量准确度高,而且量值传递性能均优于水银血压计。克服了目前无创自动血压计的主导产品,多为利用示波原理,采用系数法判定收缩压和舒张压,不仅测量准确度低,而且不能实现量值传递的问题。     

主动召回比被动召回好

《汽车产品召回监督管理条例(征求意见稿)》(以下简称条例),是对现行《缺陷汽车产品召回管理规定》(2004年)进行的全面整理和升级。相比于原规定,新《条例》中涉及法律责任的部份,占到了相当大的篇幅,而处罚力度也相当大,如对于生产者隐瞒缺陷,不启动或实施召回的,最高可对相关产品生产者处以总货值50%以下的罚款和没收非法所得;生产者不配合相关调查或提交相关报告的,也可能     

Reliability analysis of fault tolerant memory arrays

A model is developed to represent computer memory module reliability as a function of memory array reliability under a fault tolerant design. The fault tolerance feature of the array actually results from a revision in the use of the array so that with respect to some failure modes, the array becomes a K out of N rather than a series system. The model is used to determine array reliability under fault tolerance. The ratio of module reliability under fault tolerance to that without this feature is used as a measure of the benefits of revising array use. A key feature of the analysis is the fact that not all faults can be tolerated. The elemental memory devices examined conform to a decreasing Weibull hazard model. Consequently, evaluation of the general model for the K out of N system realized must be done numerically. However, for the special case in which K=N-1, a closed form expression for the performance measure is obtained. This special case occurs for the application of interest and it is shown that the performance measure always exceeds one and depends directly upon the proportion of faults that can be tolerated. Thus the value of fault tolerance is shown to depend upon the extent to which the array will tolerate faults. This provides a basis for deciding whether or not fault tolerance should be implemented.     

Any publicity is better than none: newspaper coverage increases citations, in the UK more than in Italy

A citation advantage for research covered by the mass media is a plausible, but poorly studied phenomenon. Two previous studies, both conducted in the United States, found a positive correlation between media reporting and citations. Only one of these studies was able to conclude that the correlation was caused by a real “publicity effect” rather than by the media highlighting papers that are intrinsically destined to have greater scientific impact (called the ‘earmark’ hypothesis). This study assessed the relative importance of the publicity effect outside the US, by comparing studies published in 2008 and 2009 in the Proceedings of the National Academy of Sciences that had been featured in newspapers in Italy and the United Kingdom. Newspapers in the two countries covered a similar range of topics, and tended to over-represent local (national) research. Compared to studies not appearing in any of the newspapers considered, those featured in British newspapers had around 63 % more citations, whilst in Italian newspapers 16 %. The proportion of citations from Italian authors, however, was significantly increased by newspapers, particularly by those in Italian. The equivalent effect on citations from the UK was smaller and only marginally significant. Studies accompanied by a press release did not receive, overall, significantly more citations. In sum, results suggest that the publicity effect is strongest for English-speaking media, whilst non-English reporting has mostly a local influence. These effects might represent a confounding factor in citation-based research assessment and might contribute to the many biases known to affect the scientific literature.     

Modeling and analysis of fault tolerant multistage interconnection networks

Performance and reliability are two of the most crucial issues in today's high-performance instrumentation and measurement systems. High speed and compact density multistage interconnection networks (MINs) are widely-used subsystems in different applications. New performance models are proposed to evaluate a novel fault tolerant MIN arrangement, thereby assuring performance and reliability with high confidence level. A concurrent fault detection and recovery scheme for MINs is considered by rerouting over redundant interconnection links under stringent real-time constraints for digital instrumentation such as sensor networks. A switch architecture for concurrent testing and diagnosis is proposed. New performance models are developed and used to evaluate the compound effect of fault tolerant operation (inclusive of testing, diagnosis, and recovery) on the overall throughput and delay. Results are shown for single transient and permanent stuck-at faults on links and storage units in the switching elements. It is shown that performance degradation due to fault tolerance is graceful while performance degradation without fault recovery is unacceptable.     

Cryptochrome magnetoreception: four tryptophans could be better than three

The biophysical mechanism of the magnetic compass sensor in migratory songbirds is thought to involve photo-induced radical pairs formed in cryptochrome (Cry) flavoproteins located in photoreceptor cells in the eyes. In Cry4a—the most likely of the six known avian Crys to have a magnetic sensing function—four radical pair states are formed sequentially by the stepwise transfer of an electron along a chain of four tryptophan residues to the photo-excited flavin. In purified Cry4a from the migratory European robin, the third of these flavin–tryptophan radical pairs is more magnetically sensitive than the fourth, consistent with the smaller separation of the radicals in the former. Here, we explore the idea that these two radical pair states of Cry4a could exist in rapid dynamic equilibrium such that the key magnetic and kinetic properties are weighted averages. Spin dynamics simulations suggest that the third radical pair is largely responsible for magnetic sensing while the fourth may be better placed to initiate magnetic signalling particularly if the terminal tryptophan radical can be reduced by a nearby tyrosine. Such an arrangement could have allowed independent optimization of the essential sensing and signalling functions of the protein. It might also rationalize why avian Cry4a has four tryptophans while Crys from plants have only three.     

整车电磁混合主动悬架故障诊断与容错控制研究

针对整车电磁混合悬架某一作动器发生故障,提出了一种故障诊断与容错控制方法.建立了整车7自由度模型和故障悬架模型,采用LQG控制器作为电磁混合主动悬架的常规控制器,采用未知输入观测器获取悬架的状态观测值.基于获取的悬架动挠度残差,设计了逻辑模块和稳定模块对悬架进行故障诊断.仿真分析了容错控制策略下悬架在时域和频域范围内的...     

基于COTS处理器的微小卫星软件容错策略研究

为解决基于COTS处理器的现代微小卫星系统的软件容错问题,提出了基于虚拟寄存器的软件加固技术(SHVR),它把运行在COTS处理器上的软件故障分为数据流错误和控制流错误,设计了一套虚拟寄存器分配方法来突破现有的只能采用高级语言源程序作为输入的限制,提出了基于虚拟寄存器的数据流和控制流错误检测算法,并在实际应用背景下对这一方案进行了优化.模拟实验和实际应用表明,这套完全基于软件技术的方案在平均付出82.6%性能代价的前提下,对随机注入故障检测率达到91.4%.该方法现已成功应用于哈工大某重大航天课题中.     

Scene illuminant classification: brighter is better

Knowledge of the scene illuminant spectral power distribution is useful for many imaging applications, such as color image reproduction and automatic algorithms for image database applications. In many applications accurate spectral characterization of the illuminant is impossible because the input device acquires only three spectral samples. In such applications it is sensible to set a more limited objective of classifying the illuminant as belonging to one of several likely types. We describe a data set of natural images with measured illuminants for testing illuminant classification algorithms. One simple type of algorithm is described and evaluated by using the new data set. The empirical measurements show that illuminant information is more reliable in bright regions than in dark regions. Theoretical predictions of the algorithm's classification performance with respect to scene illuminant blackbody color temperature are tested and confirmed by using the natural-image data set.     

TSAT is a better predictor than ferritin of hemoglobin response to Epoetin alfa in US dialysis patients

Clinical guidelines recommend concurrent treatment of anemia in end‐stage renal disease with erythropoiesis‐stimulating agents (ESAs) and iron. However, there are mixed data about optimal iron supplementation. To help address this gap, the relationship between iron markers and hemoglobin (Hb) response to ESA (Epoetin alfa) dose was examined. Electronic medical records of 1902 US chronic hemodialysis patients were analyzed over a 12‐month period between June 2009 and June 2010. The analysis included patients who had at least one Hb value during each 4‐week interval for four consecutive intervals (k ? 2, k ? 1, k, and k + 1; k is the index interval), received at least one ESA dose during intervals k ? 1 or k, had at least one transferrin saturation (TSAT) value at interval k, and at least one ferritin value during intervals k ? 2, k ? 1, or k. Effect modification by TSAT and ferritin on Hb response was evaluated using the generalized estimating equations approach. Patients had a mean (standard deviation) age of 62 (15) years; 41% were Caucasian, 34% African American, 65% had hypertension, and 39% diabetes. Transferrin saturation, but not ferritin, had a statistically significant (P < 0.05) modifying effect on Hb response. Maximum Hb response was achieved when TSAT was 34%, with minimal incremental effect beyond these levels. Of the two standard clinical iron markers, TSAT should be used as the primary marker of the modifying effect of iron on Hb response to ESA. Long‐term safety of iron use to improve Hb response to ESA warrants further study.     

船舶发电机组容错的StateFlow模糊PID控制研究

为了提高单个传感器故障情况下船舶柴油发电机组转速的稳定性,运用基于State Flow的模糊PID容错控制策略研究了船舶柴油发电机组传感器故障后的转速控制。研究中建立了基于Matlab的传感器故障模拟模型,基于StateFlow的故障判别方法,通过对故障传感器的估算和模糊PID控制,实现了对传感器故障后船舶柴油发电机组的转速控制。仿真结果验证了故障模型的正确性和基于StateFlow的模糊PID控制方法对传感器故障后船舶柴油发电机组转速控制的有效性。上述建模与控制的研究为进行多个传感器故障的容错控制研究奠定了基础。     

混凝土结构裂缝及防治

混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，通过对混凝土工程中常见的一些裂缝问题进行探讨分析，并针对具体情况提出了一些预防、处理措施。     

The optimal design of flexible manufacturing systems

The optimal design and control of flexible manufacturing systems is essential to minimize operating costs and enhance productivity. We present a hybrid mathematical model of a flexible manufacturing system as a closed network of queues for which the optimal cost effective system configuration is determined by a. partial implicit enumeration algorithm. The optimal configuration of both reliable and unreliable flexible manufacturing systems are considered.