• 제어로봇시스템학회논문지
• /
• 제18권3호
• /
• pp.285-294
• /
• 2012

Using bearing measurement only, target motion state is not directly obtained so that TMA (Target Motion Analysis) is needed for this situation. TMA is a nonlinear estimation technique used in passive SONAR systems. Also it is the one of important techniques for underwater combat management systems. TMA can be divided to two parts: batch estimation and sequential estimation. It is preferable to use sequential estimation for reducing computational load as well as adaptively to target maneuvers, batch estimation is still required to attain target initial state vector for convergence of sequential estimation. Selection of batch time interval which depends on observability is critical in TMA performance. Batch estimation in general utilizes predetermined batch time interval. In this paper, we propose a new method called the BTIS (Batch Time Interval and Initial State Estimation). The proposed BTIS estimates target initial status and determines the batch time interval sequentially by using a bank of GMM-TS (Gaussian Mixture Measurement-Track Splitting) filters. The performance of the proposal method is verified by a Monte Carlo simulation study.

• Journal of the Korean Statistical Society
• /
• 제29권3호
• /
• pp.319-336
• /
• 2000

A mixed model with a white noise process and an IMA(0,1,1) process is considered as a process model. It is assumed that the process is a white noise in the absence of a special cause and the process changes to an IMA(0,1,1) due to a special cause. One useful scheme in measuring the process level is to use the variable measurement interval (VMI) between measurement times according to the value of the previous chart statistic. The advantage of the VMI scheme is to measure the process level infrequently when in control to save the measurement cost and to measure frequently when out of control to save the off-target cost. This paper considers the VMI scheme in order to detect changes in the process model from a white noise to an IMA(0,1,1). The VMI scheme is shown to be effective compared to the standard fixed measurement interval (FMI) scheme in both statistical and economic contexts.

• 대한의용생체공학회:의공학회지
• /
• 제31권1호
• /
• pp.14-19
• /
• 2010

Baroreflex sensitivity (BRS) is a parameter of the cardiovascular system that is reflected in changes in pulse interval (PD and systolic blood pressure (SBP). BRS contains information about how the autonomic nervous system regulates hemodynamic homeostasis. Normally the beat-to-beat SBP measurement and the pulse interval measured from the electrocardiogram (ECG) are required to estimate the BRS. We investigated the possibility of measuring BRS in the absence of a beat-to-beat SBP measurement device. Pulse arrival time (PAT), defined as the time between the R-peak of the ECG and a single characteristic point on the pulse wave recorded from any arterial location was measured by photoplethysmography. By comparing the BRS obtained from conventional measurements with our method during controlled breathing, we confirmed again that PAT and SBP are closely correlated, with a correlation coefficient of -0.82 to -0.95. The coherence between SBP and PI at a respiration frequency of 0.07-0.12 Hz was similar to the coherence between PAT and PI. Although the ranges and units of measurement are different (ms/mmHg vs. ms/ms) for BRS measured conventionally and by our method, the correlation is very strong. Following further investigation under various conditions, BRS can be reliably estimated without the inconvenient and expensive beat-to-beat SBP measurement.

• IEIE Transactions on Smart Processing and Computing
• /
• 제5권2호
• /
• pp.117-122
• /
• 2016

Optimizing the number of ad clicks is a large-scale learning problem that is central to the multi-billion dollar mobile advertising industry. There are currently several optimization methods used, including ad mediation and ad positioning. This paper proposes a new method to optimize mobile advertising by using the ad refresh interval. A new metric, which can measure and compare mobile advertising performance, takes into account time limitations. The results achieved from this optimization study could maximize revenue for mobile advertisers and publishers. This research has high applicability. It also lays out a solid background for future research in this promising area.

• Journal of Biosystems Engineering
• /
• 제24권3호
• /
• pp.259-266
• /
• 1999

This research was carried out to investigate the possibility of real time rice milling ratio measurement using the spectral reflection characteristics. In this study, various methods were compared such as \circled1 using the whiteness meter, \circled2 using the colorimeter, \circled3 using the Visible and the NIR reflection spectrum. The samples were milled in the domain of 84~96% by 0.5% interval classified by milling ratio. The NMG treatment method required about 20 minutes to determine the milled ratio and r2 was 0.0028 to 0.7959 that was very low. In case of whiteness meter, r2 was high but speed of measurement was 5 minutes that was very low. Measurement with the colorimeter required about 5 minutes and r2 was 0.60 to 0.85 that was low. The reflection spectrum were measured in the range of 400~2,500nm with 2nm interval and the MLR model with six-wavelength obtained from first derivative of spectra gave the best results(r2 = 0.967, SEP = 0.729%)

• 한국정보통신학회논문지
• /
• 제24권7호
• /
• pp.885-890
• /
• 2020

거리측정 시스템에서 사용되는 시간-디지털 변환회로는 시작신호와 멈춤신호 사이의 시간 간격을 이용하여 거리를 측정한다. 응답속도를 고려한 시간 간격은 일반적으로 카운터 회로를 이용하여 디지털 정보로 변환한다. 그러므로 정밀도 향상을 위해서는 높은 주파수의 클록 신호가 요구되며, 미세 거리의 측정을 위해서도 높은 주파수의 클록 신호가 필요하다. 본 논문에서는 동일한 주파수를 사용하면서도 거리 측정의 정밀도를 높이기 위한 카운터 회로를 설계하였다. 회로의 설계는 0.18㎛ CMOS 공정을 이용하였으며, 설계된 회로의 동작은 HSPICE 시뮬레이션을 통하여 확인하였다. 시뮬레이션 결과 일반적인 카운터 회로를 사용한 경우에 비해 4배의 향상된 정밀도를 얻을 수 있었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1992년도 하계학술대회 논문집 B
• /
• pp.976-979
• /
• 1992

There are lots of problem which are delaminations and partial discharge of insulation materials in high-voltage rotating machines caused by mechanical, electrical and thermal aging. Several experiments have been aiming at finding the useful diagnostic parameters from the partial discharge characteristics by applying a new measurement techniques. This paper deals with the partial discharge characteristics (pulse height, pulse angle, pulse frequency spectrum and time interval), which may be a useful diagnostic concept in predicting insulation condition of mica/epoxy composite insulation materials, by using several measurement equipments (frequency spectrum analyzer. multichannel analyzer and time interval analyzer).

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.2532-2537
• /
• 2005

FIR(Finite Impulse Response) filter is well known to be ideal for the finite time state-space model, but it requires much computation due to its inherent non-recursive structure especially when the measurement interval grows to a large extent. And often a fixed-lag smoother based on the finite time interval is needed to monitor the soundness of the system model and the measurement model, but the computation burden of FIR-type smoother imposes much restriction of its usage for real-time application. Conventional recursive forms of FIR estimator[1]-[4] could not be used for real time applications, since they are numerically unstable in their recursive equations. To cope with this problem, we suggest a stable recursive form FIR estimator(SRFIR) and its usefulness is demonstrated for designing the real-time fixed-lag smoother on the finite time window through an example of detection of rate bias in the anti-aircraft gun fire control system.

• Journal of Magnetics
• /
• 제17권3호
• /
• pp.206-209
• /
• 2012

Peak interval for reversible permeability is presented for nondestructively evaluating the remanent life of 1Cr-0.5Mo steel. The method to measure the peak interval of reversible permeability is based on the value of reversible permeability is the same as the differential value of the hysteresis loop. The measurement principle is based on the first harmonics voltage induced in a sensing coil using a lock-in amplifier tuned to a frequency of the exciting voltage. Results obtained for the peak interval of reversible permeability and Rockwell hardness on the aged samples decrease as aging time and the Larson-Miller parameter increase. We could estimate the remanent life of 1Cr-0.5Mo steel by using the relationship between the peak interval of reversible permeability and the Larson-Miller parameter, nondestructively.

• 센서학회지
• /
• 제20권6호
• /
• pp.382-387
• /
• 2011

Whether a person is feeling sleepy or reasonably awake is important safety information in many areas, such as humans operating in traffic or in heavy industry. The changes of body signals have been mostly researched by looking at electroencephalogram(EEG) signals but more and more other medical signals are being examined. In our study, an electrocardiogram(ECG) signal is measured at a sampling rate of 100 Hz and used to try to distinguish the possible differences in signal between the two states: awake and drowsy. Practical tests are conducted using a wireless sensor node connected to a wearable ECG sensor, and an ECG signal is transmitted wirelessly to a base station connected to a server PC. Through the QRS complex in the ECG analysis it is possible to obtain much information that is helpful for diagnosing different types of cardiovascular disease. A program is made with MATLAB for digital signal filtering and graphing as well as recognizing the parts of the QRS complex within the signal. Drowsiness detection is performed by evaluating the R peaks, R-R interval, interval between R and S peaks and the duration of the QRS complex..