Automatic Classification of Spirometric Data

Pattern recognition principles have been applied to 200 sets of spirometric data obtained from pulmonary function laboratory patients. Each patient was classified by a pulmonary specialist as normal, restricted, or mildly, moderately, severely, or very severely obstructed. Each patient was represented by a five-element pattern vector consisting of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), midmaximum flow rate (MMFR), and flow rates with 50 and 25 percent of the vital capacity remaining (V?50 and V?25) normalized by predicted values. By Karhunen-Loeve expansion techniques, this vector was reduced to a two-feature pattern vector with only a 6 percent residual mean square representation error. The more important feature essentially represented the average of the three flow rates, while the second feature depended on FVC and FEV1. Data were divided into training and testing sets, and using the former, a parametric Bayes classifier and one-and two-layer pair-wise Fisher linear classifiers, were designed to assign patterns described by the two derived features to one of the six categories. With the testing set, overall recognition rates were 81 to 82 percent, with most errors representing misclassifications within the four obstructive categories. If the four obstructive classes were considered as a single class, the recognition rate increased to about 94 percent.     

A Statistical Evaluation of the Advantages of LANDSAT Thematic Mapper Data in Comparison to Multispectral Scanner Data

A study designed on the basis of a fixed-effects, three factor, two-level analysis or variance (ANOVA) was conducted to quantify the effect of Thematic Mapper (TM) sensor improvements on classification accuracy using TM data acquired over the Washinton, DC, area on November 2, 1982. The TM data were systematically degraded spatially, spectrally, and radiometrically to simulate the effect of changing each individual sensor parameter separately, and in conjunction with other sensor characteristics, to ultimately simulate Multispectral Scanner (MSS) data characteristics. The greatest level of variance was accounted for by the spectral waveband variable, providing an average increase in classification accuracy of 5.85 percent. This increase constituted a 21-percent relative improvement from TM data with respect to Landsat MSS data [i. e., percent relative improvement = (high accuracy value-low accuracy value)/low accuracy value X 100]. The second greatest amount of variance was accounted for by the ?radiometric? variable (i. e., bit quantization level). This provided a 5.25-percent increase in percent correctly classified pixels, which constitutes a 19-percent relative improvement of TM over MSS data due to quantization level. Spatial resolution accounted for the lowest source of variability in the observed classification accuracies, with an overall average decrease of 0.7 percent. This constituted a 2-percent relative degradation from TM data with respect to MSS data. Only the differences found for the spectral waveband combinations and the quantization level were statistically significant at ? levels of 0.01 to 0.001.     

Forced Oscillatory Parameters of the Canine Respiratory System with Altered Vagal Tone

Total respiratory impedance was obtained by forced oscillations ranging from 0.9 to 16 Hz in six anesthetized intubated dogs during a control period, after bilateral vagotomy, and during bilateral vagal stimulation. Values for forced oscillatory resistance, compliance, and inertance were calculated using regression analysis with a linear model. Mean values ±SD for the control period were 2.49 ±0.18 cmH2O ·L?1 ·s, 0.0254 ±0.0039 L ·cmH2O?1, and 0.0849 ±0.0055 cmH2O ·L?1·s2, respectively. These were similar to previously reported values. Vagotomy produced only small changes in these parameters. Vagal stimulation produced a 33 percent increase in resistance, a 20 percent decrease in compliance, and an 8 percent increase in inertance. Changes in resistance and compliance were consistent with reported effects in the literature. Thus, the transient mechanical changes induced by vagal stimulation can be characterized by this technique.     

The EE Gender Gap Is Widening

Walk into a classroom of environmental engineering students and, odds are, nearly half of them will be women. Now head next door to an electrical engineering class: you?ll likely find eight men for every woman. The failure to recruit and retain more women in electrical and computer engineering?large fields with lots of students?is a major reason the representation of women in U.S. engineering as a whole has remained so low for so long. Last year, only 18.1 percent of all bachelor?s degrees in engineering awarded by U.S. schools went to women. And things are getting worse: that?s the lowest level in more than a decade.     

The RF Pulse Susceptibility of UHF Transistors

The electromagnetic susceptibility of UHF transistors is investigated. The 2N5179 RF amplifier type transistor was selected as a representative UHF transistor because of its chip structure. It is a silicon n-p-n epitaxial planar transistor with an interdigitated baseemitter metallization pattern. Several manufacturer's versions were tested. A single RF pulse at 240 MHz was applied directly to the base terminal with the emitter terminal grounded. The incident RF pulse power required to cause a 50 percent failure rate is in the 35-70 W range for a 3 ?s pulse duration and in the 150-450 W range for a 0.3 , ?s pulse duration. The primary variable is the percentage of the incident power absorbed by the transistor. The absorbed pulse energy required to cause a 50 percent failure rate is in the 20-35 ?Joule range for 0.3-3.0, ?s pulse durations. The gs pulse and CW RF burnout powers for 2N5179 transistors are similar to those for 1N23 mixer diodes. The data suggest that UHF receivers with an RF transistor amplifier front end may be as susceptible to intense EMR at UHF frequencies as are UHF receivers with a mixer diode front end.     

Dielectric Properties of Fluid-Saturated Bone

The dielectric relaxation of bovine femoral compact bone specimens in vitro, saturated with 0.9 percent NaCI solution is determined by applying a constant current pulse and measuring the change in voltage with time. For specimens in which the current is in the plane perpendicular to the length of the whole bone and along the radial direction (radial specimens), the relaxation is confined to the time domain, t50 ?s; for longitudinal specimens, the relaxation, if any, would be for t1 ?s. The long-time resistivity of the latter is ?45 to 48 ?m; for the radial specimens, it is ?3 to 4 times greater. The resistivity of the fluid is 0.72 ?m. The results indicate that the dielectric behavior of fluid-saturated compact bone in vitro, and, hence, possibly also of in vivo bone, is determined mostly by the fluid-fllled pores. This has implications that contradict some of the commonly accepted views on the electromechanical effect in bone.     

New LSI Digital Service Units and Office Channel Units Used for NTT Digital Data Networks

Digital data services have been offered by NTT since 1978. The largest part of the entire digital data network cost is attributable to subscriber loop transmission that includes digital service units (DSU's) and office channel units (OCU's). Therefore, it is important to reduce DSU and OCU costs for economizing on digital data services. In order to achieve this purpose, new LSI DSU and OCU have been developed. The LSI is used for a digital signal processing unit, which occupies most of the equipment cost and size. The LSI can be applied to all bearer rates from 3.2 to 64 kbits/s, for NTT digital data services (leased circuit service, circuit switched service and packet switched service). It is highly significant that adoption of the LSI in DSU and OCU makes the following estimations feasible: 1) About 30 to 40 percent Cost reduction 2) About 25 percent size reduction 3) About 30 to 50 percent failure rate reduction 4) About 50 to 70 percent power consumption reduction. Summary The most expensive part of the network that carries NTT Digital Data Services is the subscriber loop transmission system, which includes DSU and OCU. This paper describes the design philosophy for introducing LSI technology in the DSU and OCU for cost reduction. Then the function, construction and evaluation are presented for the newly developed LSI DSU and OCU, based on the above design concept.     

陶瓷材料应用于激光聚光腔的实验研制

文章从陶瓷的成分配制和成形烧结等方面进行了实验研究,获得了漫反射率达99%、 功率转换率平均达4%的陶瓷激光聚光腔。     

Application of the Electrical Sizing Principle of Coulter to a New Multiparameter System

A new technique is described for simultaneously measuring, within 100 ?s, cell volume, membrane breakdown voltage, and internal conductivity on individual cells of microscopic dimensions. The system is a modification of the hydrodynamically focusing Coulter Counter?. Tumor cells established from rat fetal brain cells of average volume 2100 ?m3 were measured. A breakdown voltage of 0.86 V was found with an apparent volume underestimation after breakdown of 40 percent.     

Highly Sensitive Speech Detector and High-Speed Voiceband Data Discriminator in DSI-ADPCM Systems

This paper describes a highly sensitive speech detector and a high-speed voiceband data classifier capable of discriminating between speech and voiceband data of a 4.8 kbit/s 8-phase PSK and 4.8 kbit/s 8-point QAM, and a 9.6 kbit/s 16-point QAM as described in a CCITT recommendation. The presence of a speech signal is detected by analyzing short-time energies, zero-crossing rates, and sign bit sequences of the input signal. The proposed speech detector, with a short hangover time of 32 ms, is able to reduce the average talk spurt activity in an international satellite link to 36 percent. This detector can also classify the detected speech into narrow-band or wide-band spectrum sounds or a low power sound for a variable rate ADPCM encoding. Discrimination between speech and high-speed voiceband data is based on short-time energies, a zeros-crossing rate and linear prediction coefficients of an adaptive predictor. Classification among a 4.8 kbit/s 8-phase PSK and 8-point QAM, and a 9.6 kbit/s 16-point QAM can also be performed by an average prediction gain and a coefficient of variation of the short-term amplitude distribution of the input signal. Discrimination of voiceband data was performed successfully, and erroneous discrimination of talk spurt of telephone speech as voiceband data were, respectively, four times for two two-party conversations lasting 5 minutes in an international satellite link. This is equivalent to less than 0.09 percent of the conversation time.     

Analog Data Recording with a Video Cassette Recorder

A multichannel, analog data storage system is presented which utilizes a compact video cassette recorder. Typical video cassette recorders operate at 3?ips and consequently allow up to one hour of continuous recording. The rotary two-head, helical-scan system employed yields a relative head-to-tape speed of 404.3 ips and a bandwidth of 3 to 4 MHz. The analog recording system described herein consists of an encoder which multiplexes and digitizes eight analog signals, a video recorder for storage of the digital data, and a decoder which demultiplexes and recovers the analog information. One unique feature of this system is that digital words which are generated consist of the channel number as well as the analog information present on that channel at the time of sampling. All information is combined serially and recorded with each word uniquely separated by a special "sync pulse." Another system feature is the ability to individually select the data bandwidth of each analog channel from values between approximately 25 kHz to 3 Hz. Design, fabrication, and evaluation is given. Interfacing to computing systems and microprocessors is discussed. An eight channel system with eight bit data words is described yielding approximately one-half percent resolution. However, the system is readily expandable to any number of channels and up to 16 bit data words yielding more resolution or higher signal-to-noise ratio.     

The Application of Spectrum Signature Data to Interference Analysis

Equipment characteristics for compatibility analysis can be obtained from statistical reduction of spectrum signature data. However, practical measurement limitations such as dynamic range, receiver sensitivity, and signal generator power impose limitations on the resultant data. As a result of these limitations, certain transmitter outputs, receiver responses, or regions of an antenna pattern may be beyond the range of the measurement instrumentation. If such data are reduced without regard to the bias thus introduced, the statistical representations derived from the data samples will be in error. This paper discusses the significance of data samples obtained from a population that is ?truncated? as a result of measurement limitations, and discusses the consequences of overlooking the fact that some of the data samples are missing.     

Facial Recognition From Volume-Rendered Magnetic Resonance Imaging Data

Three-dimensional (3-D) reconstructions of computed tomography (CT) and magnetic resonance (MR) brain imaging studies are a routine component of both clinical practice and clinical and translational research. A side effect of such reconstructions is the creation of a potentially recognizable face. The Health Insurance Portability and Accountability Act of 1996 (HIPAA) Privacy Rule requires that individually identifiable health information may not be used for research unless identifiers that may be associated with the health information including ldquoFull face photographic images and other comparable imagesrdquo are removed (de-identification). Thus, a key question is: Are reconstructed facial images comparable to full-face photographs for the purpose of identification? To address this question, MR images were selected from existing research repositories and subjects were asked to pair an MR reconstruction with one of 40 photographs. The chance probability that an observer could match a photograph with its 3-D MR image was 1 in 40 (0.025), and we considered 4 successes out of 40 (4/40, 0.1) to indicate that a subject could identify persons' faces from their 3-D MR images. Forty percent of the subjects were able to successfully match photographs with MR images with success rates higher than the null hypothesis success rate. The Blyth-Still-Casella 95% confidence interval for the 40% success rate was 29%-52%, and the 40% success rate was significantly higher (P< 0.001) than our null hypothesis success rate of 1 in 10 (0.10).     

Data communications

When ``digital computer' was an institutional rather than a household word, the machine required some very special personnel to cajole anything from its limited facilities. The operators came to the computer and spoon-fed it. And the computer's limited ``brainpower' permitted only one operator at a time to tinker. Today, computers can be programmed so that almost anyone can be trained to access them?at least, in a limited way. Moreover, these electronic machines now have such massive central and peripheral memories that many people can use them simultaneously. Since it is impractical to have all of the computer users make a pilgrimage to the computer, the computer is made to come to the people that it serves. This is done via communication channels?predominantly in the telephone network. The various factors involved provide the substance for this primer article.     

An Iteratively Decodable Tensor Product Code with Application to Data Storage

The error pattern correcting code (EPCC) can be constructed to provide a syndrome decoding table targeting the dominant error events of an inter-symbol interference channel at the output of the Viterbi detector. For the size of the syndrome table to be manageable and the list of possible error events to be reasonable in size, the codeword length of EPCC needs to be short enough. However, the rate of such a short length code will be too low for hard drive applications. To accommodate the required large redundancy, it is possible to record only a highly compressed function of the parity bits of EPCC?s tensor product with a symbol correcting code. In this paper, we show that the proposed tensor error-pattern correcting code (T-EPCC) is linear time encodable and also devise a low-complexity soft iterative decoding algorithm for EPCC?s tensor product with q-ary LDPC (T-EPCC-qLDPC). Simulation results show that T-EPCC-qLDPC achieves almost similar performance to single-level qLDPC with a 1/2 KB sector at 50% reduction in decoding complexity. Moreover, 1 KB T-EPCC-qLDPC surpasses the performance of 1/2 KB single-level qLDPC at the same decoder complexity.     

多雷达数据配准的工程实现

基于雷达网系统误差分析 ,提出了一种简单、实用的数据配准算法 ,称为最小二乘相对系统误差配准法(LSRSEM ) ,并给出了一种基于相对系统误差的多雷达数据配准工程实现方法。仿真和实际数据证明 ,该方法可以使同一目标观测航迹的分裂程度减小一个数量级 ,有效保证了多雷达观测结果的一致性和连续性     

Software-Defined Data Center

Defining a software-defined data center is a vision of the future.An SDDC brings together software-defined compute,software-de fined network,software-defined storage,software-defined hypervisor,software-defined availability,and software-defined security.It also unifies the control planes of each individual software-defined component.A unified control plane enables rich resource abstrac tions for purpose-fit orchestration systems and/or programmable infrastructures.This enables dynamic optimization according to busi ness requirements.     

The present status of engineering employment

A benchmark survey of engineering employment shows the picture to be brighter than supposed?but still sobering. Results confirm many past conclusions concerning the geographic nature of the problem and highlight the degree of severity existing in mid-1971. Overall unemployment for U.S. engineering professionals who are members of engineering societies is 3.0 percent. One significant fact to emerge is that electronics engineers have an unemployment rate equivalent to that of engineers in the aerospace field; both are the highest among all engineering disciplines ?more than 5 percent.     

Spectral lines: It's Not Easy Being Lean

In seven months, a chip-fabrication plant reduced wafer-manufacturing costs by 12 percent and cycle time by 67 percent. How'd they do it?     

What to Pack for Mars

You can?t take much into space. When a rocket is on the launchpad, 99.9 percent of the mass is the fuel and the vehicle itself. That leaves 0.1 percent for everything else?the crew and all their supplies. When considering what to bring, how do we trade off between consumables (needed for survival), spare parts (for safety), and research equipment (which gives the mission value)?