Using neural networks to predict software faults during testing

This paper investigates the application of principal components analysis to neural-network modeling. The goal is to predict the number of faults. Ten software product measures were gathered from a large commercial software system. Principal components were then extracted from these measures. We trained two neural networks, one with the observed (raw) data, and one with principal components. We compare the predictive quality of the two competing models using data collected from two similar systems. These systems were developed by the same organization, and used the same development process. For the environment we studied, applying principal-components analysis to the raw data yields a neural-network model whose predictive quality is statistically better than a neural-network model developed using the raw data alone. The improvement in model predictive quality is appreciable from a practitioner's point of view. We concur with published literature regarding the number of hidden layers needed in a neural-network model. A single hidden layer of neurons yielded a network of sufficient generality to be useful when predicting faults. This is important, because networks with more hidden layers take correspondingly more time to train. The application of alternative network architectures and training algorithms in software engineering should continue to be investigated     

Using personal bibliographic databases to keep up with theengineering literature

Retrieval of bibliographic information from literature searches is now moving from the use of comprehensive centralized databases into specialized PC-mounted databases. To be effective, a personal database must take account of the structure of the literature it contains, as well as provide easy access for record entry and searching. The author describes how to design and compile a database for bibliographic engineering records. Emphasis is given to keyword selection, data record form design, and report format. Database versatility is demonstrated by an analysis of railway engineering literature, which examines the structure, sources, and locations of pertinent bibliographic material     

Attributional communication, situational involvement, self-esteem and interpersonal attraction

Two experiments were conducted which assumed that persons with extremely high or low self-esteem would be more defensive than moderate self-esteem persons when receiving ego-threatening communication. In Study I, students imagined themselves in situations in which a professor told them they had succeeded or failed on a test. For some students, success was attributed to excessive test ease, while, for others, success was attributed to high ability. For still other students, failure was either attributed to lack of ability or to excessive test difficulty. Within the Success-Environment and Failure-Environment conditions, significant curvilinear self-esteem-attraction relations were found. Study II replicated Study I. It was also found that the use of second person versus third person wordings of the simulated communication situations produced differential self-esteem-attraction relationships. Generally, the results were consistent with the ego-defense hypothesis.     

Using a modeling approach to predict soil hydraulic properties frompassive microwave measurements

A soil water and energy budget model coupled with a microwave emission model (MICRO-SWEAT) was used to predict the diurnal courses of soil surface water content and microwave brightness temperatures during a number of drying cycles on soils of contrasting texture that were either cropped or bare. The parameters describing the soil water retention and conductivity characteristics [saturated hydraulic conductivity, air entry potential, bulk density, and the exponent (b) describing the slope of the water release curve] had a strong influence on the modeled bare-soil microwave brightness temperatures. These parameters were varied until the error between the remotely sensed and modeled brightness temperatures was minimized, leading to their predicted values. These predictions agreed with the measured values to within the experimental error. The modeled brightness temperature for a soybean-covered soil was sensitive to some of the vegetation parameters (particularly to the optical depth), in addition to the soil hydraulic properties. Preliminary findings suggest that, given an independent estimate of the vegetation parameters, it may still be possible to estimate the soil hydraulic properties under a moderate vegetation canopy     

Using computational auditory models to predict simultaneous masking data: model comparison

In order to develop improved remediation techniques for hearing impairment, auditory researchers must gain a greater understanding of the relation between the psychophysics of hearing and the underlying physiology. One approach to studying the auditory system has been to design computational auditory models that predict neurophysiological data such as neural firing rates [15], [1]. To link these physiologically-based models to psychophysics, theoretical bounds on detection performance have been derived using signal detection theory to analyze the simulated data for various psychophysical tasks [20]. Previous efforts, including our own recent work using the Auditory Image Model, have demonstrated the validity of this type of analysis; however, theoretical predictions often continue to exceed experimentally-measured performance [9], [21]. In this paper, we compare predictions of detection performance across several computational auditory models. We also reconcile some of the previously observed discrepancies by incorporating appropriate signal uncertainty into the optimal detector.     

Silicon integrated circuit technology from past to future

Tremendous progress of the silicon integrated circuits (ICs) has been driven by the downsizing of their components such as MOS field effect transistors (MOSFETs) over 30 years. In order to maintain the progress for future, every dimension of the MOSFETs has to be shrunk continuously with almost the same ratio. However, the dimensions are now close to their limit of downscaling, and further reduction becomes very difficult. In order to solve the problem, the introduction of new materials and structures are seriously considered. High-k gate insulator technology is one of the examples being developed seriously to overcome the problems. In this paper, progress of silicon IC technologies for the past 30 years is described at first. Then, the difficulties of the further downsizing for future are explained in detail. Finally, the efforts to solve difficulties and the possible solutions are described.     

Looking back and to the future - leadership from a Swedish perspective

This paper describes the current situation and trends related to leadership from a Swedish perspective and from the author's personal viewpoint. The paper also identifies several key elements in creating a positive working environment and discusses the current and future challenges facing research leaders     

Charge transport model to predict dielectric breakdown as a function of voltage,temperature, and thickness

As the minimum pitch in interconnects continues to shrink, dielectric breakdown is becoming increasingly more difficult to qualify for each new technology node. Standard voltage-acceleration models provide quick, but general, assessments of the dielectric quality. Instead, a one-dimensional charge transport model has been developed as a tool to investigate the process of the dielectric breakdown and why it occurs. The model couples Poisson's equation with constitutive equations for mobile electrons, trapped electrons, and defects in the dielectric. Bonds in the dielectric matrix are weakened by the electric field, and broken by energetic electrons, creating defects. Failure occurs when a critical defect density is reached, causing trap-to-trap tunneling and an abrupt increase in the current.The model successfully replicates electrical data for leakage current and dielectric failure as a function of voltage, temperature, and thickness. The activation energy for dielectric failure is shown to increase as the electric field decreases, resulting in much higher activation energies at operating conditions compared to testing conditions. The dielectric strength also increases for decreasing thickness based on a previous theory for planar dielectrics, and is shown to cause the failure vs. field slope to increase for thinner dielectrics.     

应用CPLD实现ASI-SPI接口转换的方法

遵照国家的DVB标准及SPI接口标准,提出一种不需要使用FIFO,就能恢复出SPI接口的PSYNC、DAVLID信号的方案.经硬件实现,仅使用CPLD芯片就能完成该功能,实时稳定地产生出PSYNC、DAVLID信号,避免了使用FPGA芯片及FIFO带来的高成本问题.对SPI时钟的恢复提出一种新的解决方法,简化了ASI-SPI转换卡的硬件设计.     

Commentary: reliability-past, present, and future

The paper reviews the nature of reliability in relation to the causes of failures of engineering products, explains how most of the methods that have been developed and applied by reliability and quality specialists have been misleading and ineffective, and makes suggestions for the way ahead     

Blockage and directivity in 60 GHz wireless personal area networks: from cross-layer model to multihop MAC design

We present a cross-layer modeling and design approach for multigigabit indoor wireless personal area networks (WPANs) utilizing the unlicensed millimeter (mm) wave spectrum in the 60 GHz band. Our approach accounts for the following two characteristics that sharply distinguish mm wave networking from that at lower carrier frequencies. First, mm wave links are inherently directional: directivity is required to overcome the higher path loss at smaller wavelengths, and it is feasible with compact, low-cost circuit board antenna arrays. Second, indoor mm wave links are highly susceptible to blockage because of the limited ability to diffract around obstacles such as the human body and furniture. We develop a diffraction-based model to determine network link connectivity as a function of the locations of stationary and moving obstacles. For a centralized WPAN controlled by an access point, it is shown that multihop communication, with the introduction of a small number of relay nodes, is effective in maintaining network connectivity in scenarios where single-hop communication would suffer unacceptable outages. The proposed multihop MAC protocol accounts for the fact that every link in the WPAN is highly directional, and is shown, using packet level simulations, to maintain high network utilization with low overhead.     

Tropospheric scatter communications Past, present, and future

In the 11 years since the first practicable operational tropo systems were developed, there has been a tremendous growth in their number and complexity. This article describes the principles and applications of tropospheric scatter communications and discusses current development trends. Included is a table listing practically all of the tropo systems installed around the world, with pertinent technical data, together with maps showing the geographic location of most systems. The maps are keyed to the table for easy reference.     

Engineering management: past, present, and future

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