• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.726-729
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• 2004

Spatiotemporal phenomena are ubiquitous aspects of real world. In the spatial and temporal databases, integrity constraints maintain the semantics of specific application domain and relationship between domains when proceed update in the database. Efficient maintenance of data integrity has become a critical problem, since testing the validity of a large number of constraints in a large database and after each transaction is an expensive task. Especially, in spatiotemporal domain, data is more complex than traditional domains and very active. Additionally, it is not considered that unified frameworks deal with both spatial and temporal properties to handle integrity constraints. Therefore, there need a model to maintain integrity constraints in the unified frameworks and enforcement and management techniques in order to preserve consistence.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.136-145
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• 1997

To analyzed ride quality and to predict durability in vehicle dynamics, it is essential to describe a road surface profile precisely. This paper presents a technique to generate road surface profiles in a spatial domain by using a power spectral density function. A single track power spectral density function is proposed to describe a road surface profile, which is also applicable for multi-track vehicle response analysis, The derived road surfaces are compared to ISO(International Organization for Standardization) standards and classifications, proposed by the MIRA(Motor Industry Research Association). The methodology in this paper is also proposed to generate road roughness description with a limited external data. A small amount of external curve data is combined with an internal PSD function to generate road surface roughness in a spatial domain.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1997.11a
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• pp.91-101
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• 1997

The demand for handling images in digital form has increased dramatically in recent years. Digital image compression is required to store and transmit mass information in different from general information. JPEG(Joint Photographic Experts Group) committee founded by CCITT and ISO is define the still-image standard compression/restoration algorithm. JPEG is proposed the standard of grayscale and color still-image compression/restoration. In the image quality, JPEG is applicable to the various applications in which compression is able to from 1/10 to 1/50 without the visible obstacle. In this paper, we proposed that the proposed method enhance the compression ratio which is reducing the higher frequency in order to increasing the spatial redundancy in the image. The proposed method is using the low pass filter in order to reducing the higher frequency. The low-pass filters are using the median filter and convolution filter in the spatial domain, FFT filter in the frequency domain. We acquired the additive compression ratio reducing the higher frequency using the low-pass filter.

• Journal of The Korean Astronomical Society
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• v.27 no.2
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• pp.191-201
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• 1994

We propose to use the entropy of power spectra defined in the frequency domain for the deconvolution of extended images. Spatial correlations requisite for extended sources may be insured by increasing the role of power entropy because the power is just a representation of spatial correlations in the frequency domain. We have derived a semi-analytical solution which is found to severely reduce computing time compared with other iteration schemes. Even though the solution is very similar to the well-known Wiener filter, the regularizingng term in the new expression is so insensitive to the noise characteristics as to assure a stable solution. Applications have been made to the IRAS $60{\mu}m\;and\;100{\mu}m$ images of the dark cloud B34 and the optical CCD image of a solar active region containing a circular sunspot and a small pore.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.9-12
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• 2002

In this Paper, we propose an efficient de-interlacing algorithm using temporal and spatial domain information. In the proposed scheme, motion estimation is performed same parity fields, i.e., if current field is even field, reference fields are previous even field and forward even field. And then motion vector refinement is performed to improve the accuracy of motion vectors. In the interpolating step, we use median filter to reduce the interpolation error caused by incorrect motion vector. Simulations conducted for various video sequences have shown the efficiency of the proposed interpolator with significant improvement over previous methods in terms of both PSNR and perceived image quality.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2427-2429
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• 1998

Digital watermarking is the techinque which embeds the invisible signal into multimedia data such as audio, video, images, for copyright protection, including owner identification and copy control information. This paper proposes a new watermark embedding and extraction technique by extending the direct sequence spread spectrum technique. The proposed technique approximates the frequency component of pixels in spatial domain by using Laplacian mask and adaptively embeds the watermark considering the HVS to reduce the degradation of Image. In watermark extraction process, the proposed technique strengthens the high frequency components of image and extracts the watermark by demodulation. All this processes are performed in spatial domain to reduce the processing time.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.1
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• pp.22-28
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• 2008

In this paper, we propose a DCT coefficient domain watermarking scheme, which makes use of the sinusoidal patterns created by the watermark embedding. The embedded watermark can be detected in the spatial domain by computing the correlation. Also, the proposed algorithm can detect the spatial synchronization without additional sync bit embedding. Experimental results show that the proposed algorithm is robust to various StirMark attacks.

• Journal of the Optical Society of Korea
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• v.9 no.4
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• pp.151-156
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• 2005

A spatial-domain Fourier Transform (FT) infrared (IR) spectrometer coupled with a PtSi Schottky­barrier IR detector plane was developed in the spectral range of $2.0-2.5{\mu}m$ for noninvasive measurement of analyte concentrations in cell culture media during cell culture processing. A key optical component of the spectrometer is a Savart plate which is a birefringent polarizer generating coherent two rays for interfering. The spectral resolution of the spectrometer was determined as $71cm^{-1}$ (${\~}0.05{\mu}m$ at $2.5{\mu}m$). Clear IR fringe patterns were imaged on the IR detector plane. The feasibility of the spectrometer for our application was investigated by measuring absorbance spectra of glucose and fetal bovine serum (FBS) which are important compounds in cell culture media. Experiment results show that the spectral quality of glucose and FBS was comparable with the standard spectra acquired with a commercial FT-IR spectrometer, presenting the feasibility of the spectrometer to perform analyte measurement in cell culture media.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1040-1043
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• 2001

This paper describes the principle behind Crank Angle Analysis, as implemented by Bruel ＆ Kjaer in the Non-Stationary Spatial Transformation of Sound Fields (NS-STSF) system. The NS-STSF system combines a Time Domain Holography measurement on for example an engine with two simultaneously recorded Tacho signals. The Tacho signals provide the crankshaft angle and the RPM at the instant of each instantaneous output (snap-shot) from Time Domain Holography. As a result, the system allows precise analysis of the temporal and spatial relation between the acoustical emission (or the vibration pattern) and the mechanical events during an engine cycle. Some results from a measurement on a DaimlerChrysler engine are presented.

• Journal of the Korean Mathematical Society
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• v.58 no.5
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• pp.1227-1237
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• 2021

This paper is concerned with a reaction-diffusion logistic model. In [17], Lou observed that a heterogeneous environment with diffusion makes the total biomass greater than the total carrying capacity. Regarding the ratio of biomass to carrying capacity, Ni [10] raised a conjecture that the ratio has a upper bound depending only on the spatial dimension. For the one-dimensional case, Bai, He, and Li [1] proved that the optimal upper bound is 3. Recently, Inoue and Kuto [13] showed that the supremum of the ratio is infinity when the domain is a multi-dimensional ball. In this paper, we generalized the result of [13] to an arbitrary smooth bounded domain in ℝⁿ, n ≥ 2. We use the sub-solution and super-solution method. The idea of the proof is essentially the same as the proof of [13] but we have improved the construction of sub-solutions. This is the complete answer to the conjecture of Ni.