Measuring program execution time is a much-used technique for performance evaluation in computer science. Without proper care, however, timed results may vary a lot, thus making it hard to trust their validity. We propose a novel timing protocol to significantly reduce such variability by eliminating executions involving infrequent, long-running daemons.

Silicon Physical Unclonable Functions (PUFs) have been proposed to exploit inherent characteristics caused by process variations, such as transistor size, threshold voltage and so on, and to produce an inexpensive and tamper-resistant device such as IC identification, authentication and key generation. We have focused on the arbiter-PUF utilizing the relative delay-time difference between the equivalent paths. The conventional arbiter-PUF has a technical issue, which is low uniqueness caused by the ununiformity on response-generation. To enhance the uniqueness, a novel arbiter-based PUF utilizing the Response Generation according to the Delay Time Measurement (RG-DTM) scheme, has been proposed. In the conventional arbiter-PUF, the response 0 or 1 is assigned according to the single threshold of relative delay-time difference. On the contrary, the response 0 or 1 is assigned according to the multiple threshold of relative delay-time difference in the RG-DTM PUF. The conventional and RG-DTM PUF were designed and fabricated with 0.18 µm CMOS technology. The Hamming distances (HDs) between different chips, which indicate the uniqueness, were calculated by 256-bit responses from the identical challenges on each chip. The ideal distribution of HDs, which indicates high uniqueness, is achieved in the RG-DTM PUF using 16 thresholds of relative delay-time differences. The generative stability, which is the fluctuation of responses in the same environment, and the environmental stability, which is the changes of responses in the different environment were also evaluated. There is a trade-off between high uniqueness and high stability, however, the experimental data shows that the RG-DTM PUF has extremely smaller false matching probability in the identification compared to the conventional PUF.

We propose a real-time measurement method, DPDC (Detection of Packet-Delay Correlation), which models both available bandwidth and the averaging time scale. In this method, measurement periods are short and constant, while the theoretical measurement error is reduced. DPDC is established based on the discussion of the systematic error of the packet pair/train measurement. We evaluate through simulations its accuracy and robustness against the multihop effect. We also verify the feasibility of real-time measurements through testbed experiments using a tool called Linear that implements DPDC. Efficiency is demonstrated through simulations and testbed experiments by analyzing accidental and systematic errors. Finally, we discuss the available bandwidth variation in an Internet path using real-time data produced by Linear measurements and passive monitoring.

A method to monitor the GaInP/GaAs HBT device structure including emitter ledge thickness is demonstrated in this paper. The base thickness and base doping density are obtained through base transit time and base sheet resistance measurements while the base transit time is measured through the cut-off frequency measurements at various bias points. A large size two-emitter HBT device is used to measure the ledge thickness. Emitter doping profile and collector doping profile are obtained by the large size HBT device through C-V measurements. An FATFET device formed by two emitters as drain and source terminals and the interconnect metal as the on-ledge Schottky gate between two emitters is used to measure the ledge thickness.

A management of WWW server is still relying on the expertise and heuristic of administrators, because the comprehensive understandings of server behavior are missing. The administrators should maintain the WWW server with good states that they should investigate the WWW server in real time. Therefore, it is exactly desirable to provide a measurement application that enables the WWW server administrators to monitor WWW servers in the actual operational environment. We developed a measurement application called ENMA (Enhanced Network Measurement Agent) which is specially designed for WWW server state analysis. Furthermore, we applied this application to the large scale WWW server operation to show its implementation and advantages. In this paper, we analyze the WWW server states based on precise monitoring of performance indices of WWW system to help the server management.

While Electro-Optic (E-O) sampling has achived the electric signal measurement with advantages of noninvasive, noncontact and ultrafast time resolution, it is unsuitable for measuring long logic patterns in fast ICs under the functional test conditions. To overcome this problem, a real time E-O probing using a continuous wave (CW) diode laser and a fast photodetector has been developed. By adopting a ZnTe E-O probe having a half-wave voltage of 3.6 kV, shot noise limited measurement with a frequency bandwidth of 480 MHz has been achieved using a low noise diode laser (wavelength of 780 nm, output power of 30 mW), a pin photodiode, a wideband low noise amplifier, and a digital oscilloscope having 500 MHz bandwidth as a waveform analyzer. The minimum detectable voltage was 23 mV under 700 times integration. In this paper, discussion of the voltage sensitivity of real time E-O probing is included. Key parameters for attaining the highly sensitive real time E-O probing are the sensitivity of the E-O probe and noises of the probing light and detection system.

The development of highly accurate and durable control system is becoming a must for todays high performance automobiles. For example, it is necessary to up-grade todays materials and methods creating more sensitive sensors, higher speed processors and more accurate actuators, while also being more durable. Thus, the development of a CMOS time-to-digital converter LSI with half-nanosecond resolution, which controls only pulse signals was achieved by employing 1.5 µm CMOS technology. The new signal detecting circuit, 1.1 mm2 in size, converts time to numerical values over a wide measurement range (13 bits). The compact digital circuit employs a newly developed "ring gate delay system". Within the LSI the fully digital circuit is highly durable. This allows it to be utilized even under severe conditions (for example an operating ambient temperature of 130). In order to measure time accurately, a method of correcting the variation of measurement time data employing a real-time conversion fully digital circuit is described. This method allows for fully automatic correction with a microcomputer, so no manual adjustment is required. In addition to sensor circuit applications, the LSI has great potential for Application Specific Integrated Circuit, (ASIC) such as a function cell with is a completely new method of measuring time.

Most of actual environmental systems show a complicated fluctuation pattern of non-Gaussian type, owing to various kinds of factors. In the actual measurement, the fluctuation of random signal is usually contaminated by an external noise. Furthermore, it is very often that the reliable observation value can be obtained only within a definite fluctuating amplitude domain, because many of measuring equipments have their proper dynamic range and original random wave form is unreliable at the end of amplitude fluctuation. It becomes very important to establish a new signal detection method applicable to such an actual situation. This paper newly describes a dynamical state estimation algorithm for a successive observation contaminated by the external noise of an arbitrary distribution type, when the observation value is measured through a finite dynamic range of measurement. On the basis of the Bayes' theorem, this method is derived in the form of a wide sense digital filter, which is applicable to the non-Gaussian properties of the fluctuations, the actual observation in a finite amplitude domain and the existence of external noise. Differing from the well-known Kalman's filter and its improvement, the proposed state estimation method is newly derived especially by paying our attention to the statistical information on the observation value behind the saturation function instead of that on the resultant noisy observation. Finally, the proposed method is experimentally confirmed too by applying it to the actual problem for a reverberation time measurement from saturated noisy observations in room acoustics.