Analog to Digital Converter-Patent

Analog to digital converter for converting pulses to frequencie

Sensitive electrometer features digital output

Four-stage transistorized electrometer eliminates the need for a logarithmic compression network. It measures very low currents and produces a digital output directly indicative of the input current magnitude

A quick response four decade logarithmic high-voltage stepping supply

An improved high-voltage stepping supply, for space instrumentation is described where low power consumption and fast settling time between steps are required. The high-voltage stepping supply, utilizing an average power of 750 milliwatts, delivers a pair of mirror images with 64 level logarithmic outputs. It covers a four decade range of + or - 2500 to + or - 0.29 volts having an output stability of + or - 0.5 percent or + or - 20 millivolts for all line load and temperature variations. The supply provides a typical step setting time of 1 millisecond with 100 microseconds for the lower two decades. The versatile design features of the high-voltage stepping supply provides a quick response staircase generator as described or a fixed voltage with the option to change levels as required over large dynamic ranges without circuit modifications. The concept can be implemented up to + or - 5000 volts. With these design features, the high-voltage stepping supply should find numerous applications where charged particle detection, electro-optical systems, and high voltage scientific instruments are used

Controllable high voltage source having fast settling time

A high voltage dc stepping power supply for sampling a utilization device such as an electrostatic analyzer has a relatively fast settling time for voltage steps. The supply includes a waveform generator for deriving a low voltage staircase waveform that feeds a relatively long response time power supply, deriving a high output voltage generally equal to a predetermined multiple of the input voltage. In the power supply, an ac voltage modulated by the staircase waveform is applied to a step-up transformer and then to a voltage multiplier stack to form a high voltage, relatively poor replica of the input waveform at an intermediate output terminal. A constant dc source, applied to the input of the power supply, biases the voltage at the intermediate output terminal to be in excess of the predetermined multiple of the input voltage

High-voltage stepping supply with fast settling time

Waveform generator is used to derive low-voltage staircase waveform that feeds relatively long response time power supply. Power supply has high output voltage that is predetermined multiple of the input voltage

The electronics brain on board the X-ray telescope spectrometer experiment

System operation of electronics brain onboard X-ray telescope spectrometer experimen

Research Notes : United States : Cultivar identification by isozyme analysis

The purpose of this survey is to build a multiple enzyme system which may provide many biochemical characters to fingerprint cultivars. A total of 751 lines and cultivars of Glycine max have been screened for their enzyme zymogram types by using the technique of slab-gel electrophoresis (see Chiang, 1985; Doong, 1986; Gorman, 1983; Gorman and Kiang, 1977, 1978; Kiang and Gorman, 1983, for method). For 367 named cultivars, the zymogram types of eight enzymes and one seed protein (Ti) are listed in Table 1. Except for several cultivars, two of the eight enzymes, ADH and LAP, listed in Table 1 were mainly classified by Gorman (1983)

Virtual Machines Performance Modeling with Support Vector Regressions

Virtualization is a key technology in cloudcomputing to render on-demand provisioning of virtual services.Xen, an open source paravirtualized virtual machine monitor(hypervisor), has been adopted by many leading data centersof the world today. A scheduler in Xen handles CPU resourcessharing among virtual machines hosted on the same physicalsystem. This study is focused on a scheduler in the currentXen release - the Credit scheduler. Credit uses two parameters(weight and cap) to fine tune CPU resources sharing. Previousstudies have shown that these two parameters can impact variousperformance measures of virtual machines hosted on Xen. In thisstudy, we present a holistic procedure to establish performancemodels of virtual machines. Empirical data of two commonly usedmeasures, namely calculation power and network throughput,were collected by simulations under various settings of weightand cap. We then employed a powerful machine learning tool(multi-kernel support vector regression) to learn performancemodels from the empirical data. These models were evaluatedsatisfactorily by using established procedures in machinelearning

Monstrous ocean waves during typhoon Krosa

This paper presents a set of ocean wave time series data recorded from a discus buoy deployed near northeast Taiwan in western Pacific that was operating during the passage of Typhoon Krosa on 6 October 2007. The maximum trough-to-crest wave height was measured to be 32.3 m, which could be the largest <I>H</I><sub>max</sub> ever recorded

JWalk: a tool for lazy, systematic testing of java classes by design introspection and user interaction

Popular software testing tools, such as JUnit, allow frequent retesting of modified code; yet the manually created test scripts are often seriously incomplete. A unit-testing tool called JWalk has therefore been developed to address the need for systematic unit testing within the context of agile methods. The tool operates directly on the compiled code for Java classes and uses a new lazy method for inducing the changing design of a class on the fly. This is achieved partly through introspection, using Java’s reflection capability, and partly through interaction with the user, constructing and saving test oracles on the fly. Predictive rules reduce the number of oracle values that must be confirmed by the tester. Without human intervention, JWalk performs bounded exhaustive exploration of the class’s method protocols and may be directed to explore the space of algebraic constructions, or the intended design state-space of the tested class. With some human interaction, JWalk performs up to the equivalent of fully automated state-based testing, from a specification that was acquired incrementally