• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.10
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• pp.3275-3298
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• 2022

Cloud-based architectures for precision agriculture are domain-specific controlled and require remote access to process and analyze the collected data over third-party cloud computing platforms. Due to the dynamic changes in agricultural parameters and restrictions in terms of accessing cloud platforms, developing a locally controlled and real-time configured architecture is crucial for efficient water irrigation and farmers management in agricultural fields. Thus, we present a new implementation of an independent sensor-enabled architecture using variety of wireless-based sensors to capture soil moisture level, amount of supplied water, and compute the reference evapotranspiration (ETo). Both parameters of soil moisture content and ETo values was then used to manage the amount of irrigated water in a small-scale agriculture field for 356 days. We collected around 34,200 experimental data samples to evaluate the performance of the architecture under different agriculture parameters and conditions, which have significant influence on realizing real-time monitoring of agricultural fields. In a proof of concept, we provide empirical results that show that our architecture performs favorably against the cloud-based architecture, as evaluated on collected experimental data through different statistical performance models. Experimental results demonstrate that the architecture has potential practical application in a many of farming activities, including water irrigation management and agricultural condition control.

• Journal of applied mathematics & informatics
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• v.30 no.3_4
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• pp.381-393
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• 2012

In this paper, we show two ways of the time reparametrization of piecewise Pythagorean-hodograph $C^1$ Hermite interpolants. One is the time reparametrization with no shape change, and the other is that with shape change. We show that the first reparametrization does not depend on the boundary data and that it is uniquely determined by the size of parameter domain, up to the general cases. We empirically show that the second parametrization can cause the change of the shape of interpolant.

• 한국전산유체공학회:학술대회논문집
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• 2000.05a
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• pp.78-83
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• 2000

An iterative time marching procedure for solving incompressible internal flow has been applied to the flow around a rotor-stator. This procedure solves three-dimensional incompressible Reynolds-averaged Navier-Stokes equation on a moving, time-deforming, non-orthogonal body-fitted grid using second-order accurate schemes for the time derivatives and third/second-order accurate schemes for the spatial derivatives. To handle rotationg geometry, the multiblock technique is applied and the overall flow domain is subdivided into two blocks. In each block, a grid is generated and flowfield is solved independently of the other blocks. The boundary data for each block is provided by the neighboring blocks using bilinear interpolation technique.

• Speech Sciences
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• v.12 no.2
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• pp.153-170
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• 2005

The sub-Nyquist nonuniform sampling (SNNS) and the perfect reconstruction (PR) formula are proposed for the development of a systematic method to obtain minimal representation of a speech signal. In the proposed method, the instantaneous sampling frequency (ISF) varies, depending on the least upper boundary of spectral support of a speech signal in time-frequency domain (TFD). The definition of the instantaneous bandwidth (IB), which determines the ISF and is used for generating the set of samples that represent continuous-time signals perfectly, is given. Also, the spectral characteristics of the sampled data generated by the sub-Nyquist nonuniform sampling method is analyzed. The proposed method doesn't generate the redundant samples due to the time-varying property of the instantaneous bandwidth of a speech signal.

• Journal of Families and Better Life
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• v.16 no.1
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• pp.125-139
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• 1998

This study investigates work loads and coping strategies of the married female production workers(MFPW). The data of 370 MFPW in manufacturing sector in Taegu are collected by using a questionare in August 1995 The findings of this study are as follow: 1) The results of objective work loads assessed time dairy show that the average working hours is 14.25 hours during weekdays. The respondents spend 11.5 hours and 2.75 hours on doing paid and household work respectively,. The shortage of phisiological and leisure time due to spending excessively long time on work. 2) MFPW perceive the severe subjective work loads in the areas of personal family and social life. The perceived burden from paid work itself is relatively low due to the nature of their job. 3) The coping strategies MFPW actually adopted are limited mostly to those from an individual domain such as shortening the time for sleep leisure or household labor.

• Journal of Ocean Engineering and Technology
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• v.27 no.1
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• pp.102-108
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• 2013

In this paper time series wave data, which were measured at the Draupner platform in the North Sea on 1995, are used to investigate statistical characteristics of nonlinear wave. Various statistical properties based on time and frequency domain are examined. The Gram-Chalier distribution fits the probability of wave elevation better than the Gaussian distribution. The skewness of wave profile is 0.393 and the kurtosis is 4.037 when the freak wave is occurred. The nonlinearity of D1520 data is higher than two adjacent wave data. AI index of the New Year Wave is 2.11 and the wave height is 25.6m. The zero crossing wave period of the New Year Wave is 12.5s which is compared to the average zero up-crossing period 11.3s. The significant steepness of wave data is 0.077 when the freak wave was occurred. H1/3/${\eta}_s$ does not increases as the kurtosis increases and the values is close to 4. The New Year Wave belongs to highly nonlinear wave data packet but the AI index is within linear focusing range.

• Journal of KIBIM
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• v.13 no.3
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• pp.12-20
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• 2023

Deep learning-based anomaly detection technology is used in various fields such as computer vision, speech recognition, and natural language processing. In particular, this technology is applied in various fields such as monitoring manufacturing equipment abnormalities, detecting financial fraud, detecting network hacking, and detecting anomalies in medical images. However, in the field of construction and architecture, research on deep learning-based data anomaly detection technology is difficult due to the lack of digitization of domain knowledge due to late digital conversion, lack of learning data, and difficulties in collecting and processing field data in real time. This study acquires necessary data through IoT (Internet of Things) from the viewpoint of monitoring for environmental management of architectural spaces, converts them into a database, learns deep learning, and then supports anomaly patterns using AI (Artificial Infelligence) deep learning-based anomaly detection. We propose an implementation process. The results of this study suggest an effective environmental anomaly pattern detection solution architecture for environmental management of architectural spaces, proving its feasibility. The proposed method enables quick response through real-time data processing and analysis collected from IoT. In order to confirm the effectiveness of the proposed method, performance analysis is performed through prototype implementation to derive the results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.6
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• pp.102-109
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• 1998

As the fundamental study of an active suspension system, computer simulation is performed using a quarter model. Design data for the development of active suspension system are presented through performance estimation of active control laws in the time and frequency domain. The verification of compromise between ride quality and handling characteristics is carried out.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.146-149
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• 2008

Simulation and signal conditioning on the time domain surface elevation records are conducted to verify the proposed Welch's method in non-directional ocean wave spectrum analysis. These spectrum data are further conditioned to provide wave characteristic that better describe the sea states. Comparison of significant wave height and zero crossing period between the proposed method and a reference toolkit are presented.

• Journal of Communications and Networks
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• v.1 no.2
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• pp.81-85
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• 1999

The regrowth of OQPSK power spectral sidelobes from AM/AM and AM/PM amplifier nonlinearity is analyzed. The time-domain expression for amplifier output shows how spectral re-growth will depend on the cubic coefficient of the Taylor's series of the amplifier nonlinearity as well as input amplitude ripple. Closed form spectrum calculations show that the spectral sidelobes produced by AM/PM take the same form as those produced by AM/AM. The rate of growth of AM/PM sidelobes is, however, not as great as for AM/AM.