• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.27-37
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• 2008

Applications of 3D data increase with advancement of multimedia technique and contents, and it is necessary to manage and to retrieve for 3D data efficiently. In this paper, we propose a new method using the sliced shape which extracts efficiently a feature description for shape-based retrieval of 3D models. Since the feature descriptor of 3D model should be invariant to translation, rotation and scale for its model, normalization of models requires for 3D model retrieval system. This paper uses principal component analysis(PCA) method in order to normalize all the models. The proposed algorithm finds a direction of each axis by the PCA and creates orthogonal n planes in each axis. These planes are orthogonalized with each axis, and are used to extract sliced shape image. Sliced shape image is the 2D plane created by intersecting at between 3D model and these planes. The proposed feature descriptor is a distribution of Euclidean distances from center point of sliced shape image to its outline. A performed evaluation is used for average of the normalize modified retrieval rank(ANMRR) with a standard evaluation from MPEG-7. In our experimental results, we demonstrate that the proposed method is an efficient 3D model retrieval.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.148-154
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• 2008

In a ubiquitous computing environment, a ubiquitous smart space is required to help devices provide intelligent services. The smart space embedded with mobile devices should have the capabilities of collecting data and refining the data to contact. Unfortunately, the context information in a ubiquitous smart space has many ambiguous characteristics. Therefore, it is necessary to adapt a standard taxonomy for contact information in the smart space and to implement an inference technique of the context information based on taxonomy. Rule-based inference engine, such as CLIPS, Jess, was employed for providing situation-aware services. However, it is difficult for these engines to be used in resource limited mobile devices. In this paper, we propose a light-weight inference engine providing autonomous situation aware services in mobile environment. It can be utilized for personal mobile devices tuck as mobile phone, PMP and navigation. It can also support both generalized rules and specialized rules as using hierarchical taxonomy information.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.123-129
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• 2017

This paper proposes a new nonnegative matrix factorization (NMF) based direction-of-arrival (DOA) estimation method for multiple sound sources using a dual microphone array. First of all, sound signals coming from the dual microphone array are segmented into consecutive analysis frames, and a steered-response power phase transform (SRP-PHAT) beamformer is applied to each frame so that stereo signals of each frame are represented in a time-direction domain. The time-direction outputs of SRP-PHAT are stored for a pre-defined number of frames, which is referred to as a time-direction block. Next, In order to estimate DOAs robust to noise, each time-direction block is normalized along the time by using a block subtraction technique. After that, an unsupervised NMF method is applied to the normalized time-direction block in order to cluster the directions of each sound source in a multiple sound source environments. In particular, the activation and basis matrices are used to estimate the number of sound sources and their DOAs, respectively. The DOA estimation performance of the proposed method is evaluated by measuring a mean absolute error (MAE) and the standard deviation of errors between the oracle and estimated DOAs under a three source condition, where the sources are located in [$-35{\circ}$, 5m], [$12{\circ}$, 4m], and [$38{\circ}$, 4.m] from the dual microphone array. It is shown from the experiment that the proposed method could relatively reduce MAE by 56.83%, compared to a conventional SRP-PHAT based DOA estimation method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.2
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• pp.30-38
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• 2002

In this paper, we propose a new method for image coding which efficiently use the relationship between the properties of spatial image and its wavelet transform. Firstly, an original image is decomposed into several layers by the wavelet transform, and simultaneously decomposed into 2$^n$$\times$2$^n$blocks. Each block is classified into two regions according to their standard deviation, i.e., low activity region(LAR) and high activity region(HAR). The region with low frequency in spatial domain does not only appears as zero regions in wavelet frequency domain like HL, LH, and HH but also gives little influence to the quality of reconstructed image. The other side, the high frequency regions are related to significant coefficients which gives much influence to image reconstruction. In this paper, we propose a image coding method to obtain high compression rate at low bit rate by these properties. The LAR region is encoded by LAR coding method which is proposed in this paper, the HAR by a technique similar to bitplane coding in hierarchical tree. Simulation results show that th,$\boxUl$ proposed coding method has better performance than EZW and SPIHT schemes in terms of image quality and transmitted bit rates, can be successfully applied to the application areas that require of progressive transmission.

• Korean Journal of Social Welfare
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• v.68 no.3
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• pp.73-103
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• 2016

In this study, it investigates the life of normal adolescents who have parents with intellectual disability and their difficulties which suggested social welfare meanings of this study. In order to conduct wide and in-depth analysis on cases by utilizing the characteristics of qualitative case studies, it describes and analyzes the intellectual disability parents' normal children in detail from the viewpoint of an insider through in-depth interviews, various sources and diverse data collecting methods. As for the subject of this study, both parents should be persons with intellectual disability and their child shall be non-disabled and at least a high school student or older. Through the intentional sampling, five late adolescents who were in high school, all males participated in the study. The data collection process had been conducted from January 2014 to May, which is commonly utilized for qualitative case studies, and comparative analysis between cases were practiced for analysis. For credibility of the research results, it obtained severity at each stage by meeting the standard. The analysis results were largely divided into "growth story of non-disabled adolescents" and "life of non-disabled adolescents". Nine upper categories analyzed the common features in each case. The nine categories were "no one tells me to study", "advance while learning the sense of academic achievement", "hide into my own space", "having to grown up early", "different parents but same love", "relatives raised me", "have a friend who accepts me as I am", "being pressed by poverty", and "standing on a knife edge of being hurt and taking heart". Based on the in-depth research on normal teens that have intellectually disabled parents, theoretically speaking, this study expanded the prospect of study on intellectually disabled to their normal, intellectual teenage children. As for practical significance, understanding their parents' intellectual disability, parenting technique training, case management from the community level is suggested. Rregular real condition research of the families, allowance system for economic support et al. is suggested in policy aspect.

• Journal of the Korea Institute of Building Construction
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• v.18 no.1
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• pp.17-24
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• 2018

The pullout test, a nondestructive testing(NDT), for pre-installed inserts is perhaps the most widely used technique to estimate the in-situ compressive strength of concrete. It measures the force needed to pullout a standardized metal insert embedded into concrete members. The pullout test was certified by the American Society for Testing and Materials(ASTM) and Canadian Standards Association(CSA) as a reliable method for determining the strength of concrete in concrete structures under construction. To easily estimate the strength of ultra-high-strength concrete, a simplified pullout tester, primarily composed of a standard 12mm bolt with a groove on the shaft as a break-off bolt, an insert nut, and a hydraulic oil pump without a load cell, was proposed. Four wall and two slab specimens were tested for two levels of concrete strength, 80MPa and 100MPa, using a simplified pullout tester with a load cell to verify the advantages of the pullout test and simplified pullout test. The compressive strength of concrete, pullout load, and the rupture of the break-off bolt were measured 11 times, day 1 to 7, 14, 21, 28, and 90. The correlation of the pullout load and the compressive strength of each specimen show a higher degree of reliability. Therefore, a simplified pullout test can be used to evaluate the in-place strength of ultra-high-strength concrete in structures. The prediction equation for the groove diameter of the break-off bolt(y) with the concrete strength(x) was proposed as y=0.0184x+5.4. The results described in this research confirm the simplified pullout's utility and potential for low cost, simplicity, and convenience.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.385-390
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• 2006

This paper examines the sampling and jitter specifications and considerations for Global Navigation Satellite Systems (GNSS) software receivers. Software radio (SWR) technologies are being used in the implementation of communication receivers in general and GNSS receivers in particular. With the advent of new GPS signals, and a range of new Galileo and GLONASS signals soon becoming available, GNSS is an application where SWR and software-defined radio (SDR) are likely to have an impact. The sampling process is critical for SWR receivers, where it occurs as close to the antenna as possible. One way to achieve this is by BandPass Sampling (BPS), which is an undersampling technique that exploits aliasing to perform downconversion. BPS enables removal of the IF stage in the radio receiver. The sampling frequency is a very important factor since it influences both receiver performance and implementation efficiency. However, the design of BPS can result in degradation of Signal-to-Noise Ratio (SNR) due to the out-of-band noise being aliased. Important to the specification of both the ADC and its clocking Phase- Locked Loop (PLL) is jitter. Contributing to the system jitter are the aperture jitter of the sample-and-hold switch at the input of ADC and the sampling-clock jitter. Aperture jitter effects have usually been modeled as additive noise, based on a sinusoidal input signal, and limits the achievable Signal-to-Noise Ratio (SNR). Jitter in the sampled signal has several sources: phase noise in the Voltage-Controlled Oscillator (VCO) within the sampling PLL, jitter introduced by variations in the period of the frequency divider used in the sampling PLL and cross-talk from the lock line running parallel to signal lines. Jitter in the sampling process directly acts to degrade the noise floor and selectivity of receiver. Choosing an appropriate VCO for a SWR system is not as simple as finding one with right oscillator frequency. Similarly, it is important to specify the right jitter performance for the ADC. In this paper, the allowable sampling frequencies are calculated and analyzed for the multiple frequency BPS software radio GNSS receivers. The SNR degradation due to jitter in a BPSK system is calculated and required jitter standard deviation allowable for each GNSS band of interest is evaluated. Furthermore, in this paper we have investigated the sources of jitter and a basic jitter budget is calculated that could assist in the design of multiple frequency SWR GNSS receivers. We examine different ADCs and PLLs available in the market and compare known performance with the calculated budget. The results obtained are therefore directly applicable to SWR GNSS receiver design.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.802-808
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• 2010

This study was carried out to apply the method of priority order selection for water quality improvement of watershed. The monitoring of flow and water quality, grouping branch streams and discharge load density were estimated on 18 branch streams located in middle and lower area of Geum River, Chungcheongnam-do. Based on average BOD concentration of stream at low flow, the results of the water quality analysis of stream which excess river living standard class 2 (less than BOD 3 mg/L) are Jeongancheon, Bangchukcheon, Gilsancheon, Jocheon, Seokseongcheon and Ganggyeongcheon. As a result of grouping stream, stream that have more than $10\;m^3/min$ of flow and more than 3.0 mg/L of average BOD concentration such as Group A are Jocheon, Seokseongcheon, Ganggyeongcheon and Jeongancheon. In Group A, stream corresponds to over than discharge load density as of 10 BOD kg/$day{\cdot}km^2$ is Jocheon, Seokseongcheon and Ganggyeongcheon. In view of the selected results to improve water quality basin through monitoring of flow and water quality, grouping stream, and estimation of discharge load density, Jocheon in Yeongi, Seokseongcheon located on the border of Buyeo and Nonsan, Ganggyeongcheon on Nonsan such as stream basin were urgent to improve water quality.

• Analytical Science and Technology
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• v.25 no.2
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• pp.146-151
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• 2012

An analytical method was developed for the measurement of uranium isotope in ground water using the liquid scintillation counting technique. A LKB Wallac Quantulus 1220 liquid scintillation counter (LSC) equipped with pulse shape analyzer (PSA) and a solvent extraction method were used for the measurement of uranium isotope in ground water samples. The effect of solution volume on the extraction efficiency was evaluated for 100 to 1000 mL solutions using a NIST standard reference material (NIST SRM 4321C). The effect of groundwater pH on the extraction efficiency was also investigated for pH ranging from 0.5 to 10. It was found that the extraction efficiency had a strong dependence on pH showing a maximum at pH 2. In contrast, the effect of groundwater volume on the extraction efficiency was negligible in the range investigated. According to the method, the extraction efficiency of uranium isotopes was near 96% and the lower detection limit for uranium was 0.018 Bq/L with the counting time of 300 min. The result of this study was also verified by the conventional ICP-MS measurement. It is demonstrated that the suggested method is valuable to the determination of the optimum extraction and measurement conditions for uranium in ground water. The method was successfully applied to the ground water at four locations near the Daejeon province. It was found that the uranium content and the isotopic ratio of $^{234}U/^{238}U$ at the locations ranged 0.59~6.69 Bq/L and 0.72~1.40, respectively.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.1035-1052
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• 2019

Recently, as the demand for immersive videos increases, efficient video processing techniques for omnidirectional immersive video is actively developed by MPEG-I. While the omnidirectional video provides a larger degree of freedom for a free viewpoint, the size of the video increases significantly. Furthermore, in order to compress 6 degree-of-freedom (6 DoF) videos that support motion parallax, it is required to develop a codec to yield better coding efficiency. In this paper, we develop a 6 DoF codec using Versatile Video Coding (VVC) as the next generation video coding standard. To the authors' best knowledge, this is the first VVC-based 6 DoF video codec toward the future ISO/IEC 23090 Part 7 (Metadata for Immersive Media (Video)) MPEG-I standardization. The experiments were conducted on the seven test video sequences specified in Common Test Condition (CTC) in two operation modes of TMIV (Test Model for Immersive Media) software. It is demonstrated that the proposed codec improves coding performance around 33.8% BD-rate reduction in the MIV (Metadata for Immersive Video) mode and 30.2% BD-rate reduction in the MIV view mode as compared to the state-of-the-art TMIV reference software. We also show the performance comparisons using Immersive Video PSNR (IV-PSNR) and Mean Structural Similarity (MSSIM).