An accurate and practical buffer allocation model for the buffer cache based on marginal gains

A new dynamic buffer allocation strategy based on the notion of marginal gains is presented for the buffer cache that is used by the operating system to store frequently accessed disk blocks in main memory, and the performance of the proposed strategy is compared with those of previous allocation strategies. In the proposed strategy, marginal gain values are predicted by exploiting functions that approximate the expected number of buffer hits per unit time. Experimental results from both trace-driven simulation and an actual implementation in the FreeBSD operating system show that the proposed strategy accurately predicts the marginal gain values for various workloads resulting in significantly improved buffer hit ratios.     

An Area Optimization Method for Digital Filter Design

In this paper, we propose an efficient design method for area optimization in a digital filter. The conventional methods to reduce the number of adders in a filter have the problem of a long critical path delay caused by the deep logic depth of the filter due to adder sharing. Furthermore, there is such a disadvantage that they use the transposed direct form (TDF) filter which needs more registers than those of the direct form (DF) filter. In this paper, we present a hybrid structure of a TDF and DF based on the flattened coefficients method so that it can reduce the number of flip‐flops and full‐adders without additional critical path delay. We also propose a resource sharing method and sharing‐pattern searching algorithm to reduce the number of adders without deepening the logic depth. Simulation results show that the proposed structure can save the number of adders and registers by 22 and 26%, respectively, compared to the best one used in the past.     

半导体晶圆制造车间层控制的内容及方法

半导体晶圆制造企业是资本密集、技术密集型产业,晶圆制造厂也是公认生产最为复杂的工厂之一。产品更新换代快、市场竞争激烈等特点使得投资者对设备产能和设备利用率高度重视。这已不仅仅是技术问题,而是生产制造过程管理的问题。本文介绍了半导体晶圆制造车间层控制的内容及方法。     

高入纤功率光纤通信系统的可靠性研究

掺铒光纤放大器(EDFA)和拉曼放大器(FRA)的使用,使得光纤通信系统中的入纤功率有了很大的提高.较高的入纤功率不仅会在光纤中引起各种非线性效应,对光脉冲的传输产生影响,也会对光纤本身的可靠性产生影响,为此介绍了高入纤功率对光纤系统的影响,分析了其产生的机理,并提出了应对措施.     

Robust Space Time Receiver for CDMA-based Antenna Arrays

In this paper, we propose a new robust code division multiple access (CDMA) receiver of which weight vector is obtained by projecting the effective spatio-temporal signature waveform onto the signal subspace of the data covariance matrix. We verified our proposed algorithm by the field measured data obtained with a custom-built wideband CDMA test-bed. It will be shown that the proposed algorithm is robust to the signal mismatch.     

氧化酶复合乳化剂在面条中的应用研究

利用正交试验研究了葡萄糖氧化酶、抗坏血酸和SSL-CSL对面团粉质特性和面条品质的影响。结果表明,葡萄糖氧化酶对面团稳定时间影响最大,SSL-CSL对面条的烹调性影响最大,其适宜的用量为葡萄糖氧化酶0.004%、SSL-CSL 0.5%、抗坏血酸0.008%。     

Considerations for polarization insensitive optical switching and modulation using strained InGaAs/InAlAs quantum well structure

It is shown that In/sub 1-x/Ga/sub x/As/In/sub 0.52/Al/sub 0.48/As MQW structures with the wells under tensile strain obtained by the appropriate selection of the Ga mole fraction and well size can achieve polarization-insensitive optical switching and modulation for a wide range of wavelengths between 1.0 and 1.6 mu m. For example, a change in refractive index of -0.5% at about 1.55 mu m will facilitate an intersectional angle of more than 10 degrees in a total internal reflection switch which can be readily fabricated. Hence, this material system is promising for long-wavelength polarization-insensitive semiconductor optoelectronic devices.<>     

纳米β-Ni(OH)2与球型Ni(OH)2的热性能比较研究

用配位沉淀法合成出纳米级Ni（OH）2，并对其进行XRD，TEM，DSC分析，分析结果表明，所得纳米β-Ni（OH）2为可用作电极材料的β-Ni（OH）2，粒径为30－40nm，且热分解温度比普通球镍低10℃左右，摩尔分解热比普通球镍低4－7kJ，从理论上分析了产生此现象的原因。     

采用活性非均匀分布催化剂中变反应器的模拟计算

模拟计算表明:采用活性趋于表层的分布,可以较明显地提高国产中温变换催化剂的内表面利用率,有效地节省催化剂用量,而对“热点”温度没有多大影响。     

Theoretical foundation of the 80/20 rule

A rigorous analysis of the 80/20 rule is made using an index for the observed values of the variables. Three important findings are identified. First, a sufficient condition is provided for Burrell's inverse relationship between minimum holdings and average circulation rate. Second, an indexed version of Lotka's law is used to derive a sufficient condition for Egghe's finding on the 80/20 rule. Third, through the computer simulations of the Simon-Yule model of Lotka's law, we identify the entry rate of new holdings as well as the number of circulations when the entry rate is a decreasing function to be crucial factors for the pattern of the 80/20-type curve.