新型集成电路简化嵌入式POL DC/DC转换器设计

1、背景大多数嵌入式系统都是由48V背板供电的。这个电压通常要降至较低的12V或5V中间电压,以向系统内的电路板支架供电。然而,这些电路板上的大多数分支电路或集成电路所要求的供电电压范围为0.8V至3.3V,供电电流范围为数十毫安至数十安培。结果,需要负载点(POL)DC/DC转换器将12V或5V电压降低至这些分支电路或集成电路所需的电压和电流值。     

An analytic simplification for the reconstruction problem of electrical impedance tomography

This paper introduces a new reconstruction algorithm for electrical impedance tomography. The algorithm assumes that there are two separate regions of conductivity. These regions are represented as eccentric circles. This new algorithm then solves for the location of the eccentric circles. Due to the simple geometry of the forward problem, an analytic technique using conformal mapping and separation of variables has been employed. © 2002 John Wiley & Sons, Inc. Int J Imaging Syst Technol 12, 9–15, 2002     

A directional coupler acoustooptic filter with reduced sidelobelevels

A two-waveguide directional coupler filter with an acoustically induced grating structure is proposed. The directional coupler filter has the advantage that it does not require input and output polarizers and does not require specific birefringent material properties. Since multiple acoustic waves could be applied simultaneously, this property could be used to couple both TE and TM polarizations from one waveguide to the other. This allows for filtering the required optical wavelength from both polarizations simultaneously. A notable weakness of acoustooptical filters and all mode-coupling filters is the high sidelobe levels in their optical transmission spectrum. A technique to suppress these high sidelobe levels in the proposed acoustooptic filter is presented. It is based on simultaneous application of several acoustic waves on the optical waveguide. This technique could be applied to any existing configuration of acoustooptic filters     

Improving the dispersion of surplus labor in personnel scheduling solutions

Linear programming-based heuristics for personnel tour scheduling have focused primarily upon the minimization of the workforce size (or cost) necessary to satisfy forecast demand. There are often a myriad of alternative optimal LP solutions and these solutions may differ substantially in terms of secondary criteria. An even dispersion of surplus labor, which is associated with consistent customer service and employee workload, is one of the most important of these secondary criteria.

This paper presents a two-stage preemptive goal programming (PGP) approach that enables service operations managers to provide a more even dispersion of surplus labor while maintaining low-cost solutions. The cost incurred for improved surplus dispersion is the time required to run a second mathematical programming model (in this study 1–4 min on a 386 PC). If management has already invested the resources to use LP-based scheduling methods, implementing this alternative model would result in greater consistency of employee workload and customer service.     

THE EFFECT OF OSMOTIC PRESSURE ON THE INTRACELLULAR ACCUMULATION OF ETHANOL IN SACCHAROMYCES CEREVISIAE DURING FERMENTATION IN WORT

An intracellular accumulation of ethanol was observed in Saccharomyces cerevisiae during the early stages of fermentation (3 h) in wort. However, after 12 h fermentation, the intracellular and extracellular ethanol concentrations were similar. Increasing the osmotic pressure in wort by adjusting the carbohydrate concentration, from 10° to 20° plato, was observed to cause an increase in intracellular ethanol concentration and glycerol production. Although intracellular ethanol concentration increased, no adverse effect was observed on cell growth and fermentation rates. Thus, increasing the carbohydrate concentration in wort to at least 20° plato did not affect cell growth and fermentation rates, but did result in the production of more ethanol.     

Redundancies and don't cares in sequential logic synthesis

The relationships between redundant logic and don't care conditions in combinational circuits are well known. Redundancies in a combinational circuit can be explicitly identified using test generation algorithms or implicitly eliminated by specifying don't cares for each gate in the combinational network and minimizing the gates, subject to the don't care conditions.In this article, we explore the relationships between redundant logic and don't care conditions in sequential circuits. Stuck-at faults in a sequential circuit may be testable in the combinational sense, but may be redundant because they do not alter the terminal behavior of a nonscan sequential machine. These sequential redundancies result in a faulty State Transition Graph (STG) that is equivalent to the STG of the true machine.We present a classification of redundant faults in sequential circuits composed of single or interacting finite state machines. For each of the different classes of redundancies, we define don't care sets which if optimally exploited will result in the implicit elimination of any such redundancies in a given circuit. We present systematic methods for the exploitation of sequential don't cares that correspond to sequences of vectors that never appear in cascaded or interacting sequential circuits. Using these don't care sets in an optimal sequential synthesis procedure of state minimization, state assignment, and combinational logic optimization results in fully testable lumped or interacting finite state machines. We present experimental results which indicate that medium-sized irredundant sequential circuits can be synthesized with no area overhead and within reasonable CPU times by exploiting these don't cares.     

Peace in the woods: sustainability and the democratization of land use planning and resource management on Crown lands in British Columbia

During the 1990s, the provincial government of British Columbia made the introduction of participatory processes into the land use planning and resource management of its Crown lands the central element of its attempt to defuse conflictual relationships over choices affecting the sustainability of the province's development strategies. The processes used to this end are examined, and evidence of the resulting outcomes is evaluated. As well as the planning gains associated with the switch from techno‐corporatist to consensual decision‐making for the province's publicly owned resource base, studies indicate that there will be substantial ecological benefits from zoning an additional 30% of Crown lands for enhanced protection, at little economic cost to rural industries. The new rural planning regime also offers a consensual management system capable of assimilating the tribal holdings created by the settlement of First Nation claims on Crown lands. Overall, the evidence indicates that substantial benefits have emerged from the application of procedural environmental justice to formerly highly technocratic management processes, not least of which is delivery of “peace in the woods”.     

使用PowerShell管理组（二）——通过脚本化Exchange组管理任务节省时间

使用Windows PowerShell和Exchange Management Shell扩展维护组成员关系并管理动态的Exchange和Windows组。您可以在本刊网站本期目录下下载文中列表。