时钟抖动和相位噪声对采样系统的影响

随着直接中频采样的更高分辨力数据转换器的上市，系统设计师必须对低抖动时钟电路做出有助于性能与成本折衷的抉择。制造商用来规定时钟抖动的很多传统方法并不适用于数据转换器，或者说，充其量也只能反映问题的一部分。如果对时钟电路的规范和设计没有恰当的了解，你就不能实现这些数据转换器的最佳性能。     

Who wins when price information is more ubiquitous? An experiment to assess how infomediaries influence price

Internet retailers often make use of price search services (infomediaries) that have the effect of reducing consumer search and expanding seller market presence. Research on price and advertising suggests that this may not be a profitable strategy. We develop an experimental posted-offer market to estimate the impact of infomediaries on price of homogenous goods. We analyze panel data from a range of market conditions that address how infomediaries services affect both seller-level offered price as well as market-level transacted price. We find that, while sellers attempt to extract higher prices through a higher initial offer price when using an infomediary, they fail to successfully collect it; transacted prices remain largely unchanged. As a consequence the benefits of infomediaries fall primarily to the buyer who faces largely unchanged transacted prices, and substantially reduced search costs. Search costs are, in essence shifted to the seller. Sellers who participate in this sort of price comparison should be aware that they are following a high-volume/low profit per unit strategy.     

Modeling expert problem solving in a game of chance: a Yahtzee© case study

Although developments on software agents have led to useful applications in automation of routine tasks such as electronic mail filtering, there is a scarcity of research that empirically evaluates the performance of a software agent versus that of a human reasoner, whose problem-solving capabilities the agent embodies. In the context of a game of a chance, namely Yahtzee©, we identified strategies deployed by expert human reasoners and developed a decision tree for agent development. This paper describes the computer implementation of the Yahtzee game as well as the software agent. It also presents a comparison of the performance of humans versus an automated agent. Results indicate that, in this context, the software agent embodies human expertise at a high level of fidelity.     

Crossing the divide: Infants discriminate small from large numerosities.

Although young infants have repeatedly demonstrated successful numerosity discrimination across large sets when the number of items in the sets changes twofold (E. M. Brannon, S. Abbott, & D. J. Lutz, 2004; J. N. Wood & E. S. Spelke, 2005; F. Xu & E. S. Spelke, 2000), they consistently fail to discriminate a twofold change in number when one set is large and the other is small (     

九项您非懂不可,又老是忽视的ADC规格

现在虽然有那么多颗模拟数字转换器（ADC）可供挑选,但是在应用设计时,想了解哪一颗ADC合用,就绝对没有那么简单。技术手册往往让这个问题变得更加复杂,更何况有好多项规格根本是以料想不到的方式在影响性能。     

Hypervariate constitutive modeling illustrated via aleatory uncertainty in a foundation model

Even if a ceramic's homogenized properties (such as anisotropically evolving stiffness) truly can be predicted from complete knowledge of sub-continuum morphology (e.g., locations, sizes, shapes, orientations, and roughness of trillions of crystals, dislocations, impurities, pores, inclusions, and/or cracks), the necessary calculations are untenably hypervariate. Non-productive (almost derailing) debates over shortcomings of various first-principles ceramics theories are avoided in this work by discussing numerical coarsening in the context of a pedagogically appealing buckling foundation model that requires only sophomore-level understanding of springs, buckling hinges, dashpots, etc. Bypassing pre-requisites in constitutive modeling, this work aims to help students to understand the difference between damage and plasticity while also gaining experience in Monte-Carlo numerical optimization via scale-bridging that reduces memory and processor burden by orders of magnitude while accurately preserving aleatory (finite-sampling) perturbations that are crucial to accurately predict bifurcations, such as ceramic fragmentation.     

Excimer-laser ablation and etching

The characteristics of excimer lasers and the nature of ablation and etching processes are described. The two kinds of laser ablation mechanisms, thermal and electronic, are discussed. Thermal processes all rely on an intense laser pulse to heat a surface very rapidly. Electronic mechanisms do not rely on heating. Two of these quantum-type processes have been discussed widely. In the first, laser photons directly excite and break the bonds of the solid, causing ejection of material. In the second, photoexcitation creates electron-hole pairs, the potential energy of which can be coupled directly into kinetic energy of the atoms via a radiationless process. The energized atoms are able to overcome the surface binding energy, and again material is ejected. Pulsed laser etching has many of the same physical-interaction mechanisms as laser ablation but requires an active chemical medium to be in contact with the solid because laser-induced chemical reactions serve as the driving force for material removal. Issues that must be addressed prior to the successful implementation of an excimer-laser fabrication tool are discussed. The use of patterned beams for direct patterning of surfaces is considered. Microelectronic applications suitable for excimer-laser ablation and etching are examined