• The Journal of the Acoustical Society of Korea
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• v.18 no.8
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• pp.32-41
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• 1999

In this paper, an inversion method using chirp signals and two near field receivers is proposed. Inversion problems can be formulated into the probabilistic models composed of signals, a forward model and noise. Forward model to simulate chirp signals is chosen to be the source-wavelet-convolution planewave modeling method. The solution of the inversion problem is defined by a posteriori pdf. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the ranges for a priori uniform distribution is based. The genetic algorithm can be applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L₂norm of the difference between measured and modeled signals. The observed signals can be separated into a set of two signals reflected from the upper and lower boundaries of a sediment. The separation of signals and successive applications of the genetic algorithm optimization process reduce the search space, therefore improving the inversion results. Not only the marginal pdf but also the statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. The examples applied here show that, for synthetic data with noise, it is possible to carry out an inversion for sedimentary layers using the proposed inversion method.

• The Research Journal of the Costume Culture
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• v.26 no.5
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• pp.727-743
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• 2018

In this study, we used the 3D simulation program to create bodice patterns for adolescents boy students and analyze the fitting and air gap through 3D simulation. The purpose of this study was to select the bodice pattern method that best suited the body shapes of the adolescents male students. The subjects of this study were the French E pattern, Japanese N pattern, and Korean industrial L and J patterns. The applied size was the sixth Korean human body size survey data of 2010 Korea. The age range of the subjects was 13-18 years. DC Suite Program Ver. 5.1 was used, and SPSS 23.0 program was used for data analysis. As a result of comparing the shapes of the bodice patterns in the 3D simulation program, the E pattern had two waist darts on the front and one shoulder dart and one waist dart on the back, and the J and L patterns only had one dart on the back. The N pattern had no darts on either the front or back. As a result of examining the appearance evaluation of the pattern, air gap, color distribution, and clothing cross-section, the E pattern was evaluated as the closest to the body, and the N pattern was evaluated as the pattern with the largest allowance. The J pattern was evaluated as the best fit for body shape of the male adolescents. However, it is necessary to develop a pattern system by adding extra ease in setting the center front length.

• Journal of IKEEE
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• v.13 no.3
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• pp.62-71
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• 2009

In this study, we developed a wireless CROS(contralateral routing of signal) hearing aid for unilateral impaired people. CROS hearing aid takes sound from an ear with poorer hearing and transmit to another ear with better hearing. Generally, the self-voice delivered through the receiver of CROS hearing aid can be very loud. It is hard to perceive target speech because of loud self-voice. To compensate it, a self-voice suppression algorithm has been developed. we performed SDT(speech discrimination test) for evaluation of the self-voice suppression algorithm. One-syllable words was used as test speech and recorded with self-voice at a 1m distance. As the results, SDT score was improved about 11% when the self-voice suppression algorithm was processed. It is verified that the self-voice suppression algorithm helps speech perception at a time to communicate with others.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.3
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• pp.395-407
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• 2008

As global interest in clothing spreads over the smart clothing which arouses high added-value in the apparel industry, this study is to develop a smart jacket with an electrically-vibrating device maintaining excellent appearance and comfort. The vibrating device has a massage function that could relieve muscle pain near shoulders and neck. The purposes of this research are to develop jacket pattern for men in their thirties considering body shapes and fashion trend, to develop a wearable device that is composed of motor and controller and integrate it into a jacket, and to assess the external appearance and functional satisfaction of the smart jacket through the wearing test. The results are as follows: 1. In order to develope an appropriate jacket pattern for men in their thirties, several patterns were assessed for their fitting comfort. The final pattern was completed after making alterations some parts, and showed high satisfaction as 3.6(on a five-point scale) in all categories. 2. A vibrating device was developed by connecting motor, controller, battery and switch. Developing this device, focus was maximizing the strength of motor and minimizing the heat generated from motor and controller. Snaps were placed between inner and outer cloth of jacket so that the vibrating device could be easily attachable and detachable. The motor was located around Trapezius where muscles often get stiff. A switch was designed to be used in selecting the modes of Strong, Weak, and Cross Tapping. 3. The wearing test was conducted to examine outer appearance, comfort for motion, and functionality of the smart jacket. The results of assessing outer appearance showed that the location for attaching the vibrating device was not noticeable but looked natural, and there is almost no change in outer appearance when the vibrating device operates. The result of assessing comfort of action revealed that wearer's satisfaction was high in all categories about activity, wearer's comfort, etc. The result also showed that wear's satisfaction for effects of vibrating massage, easiness in using the device, heat generation was not less than 3.5 in all categories except a category about noise.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.158-164
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• 2015

Lane detection is one of the key parts among autonomous vehicle technologies because lane keeping and path planning are based on lane detection. Camera is used for lane detection but there are severe limitations such as narrow field of view and effect of illumination. On the other hands, Lidar sensor has the merits of having large field of view and being little influenced by illumination because it uses intensity information. Existing researches that use methods such as Hough transform, histogram hardly handle multiple lanes in the co-occuring situation of lanes and road marking. In this paper, we propose a method based on RANSAC and regularization which provides a stable and precise detection result in the co-occuring situation of lanes and road marking in highway scenarios. This is performed by precise lane point extraction using circular model RANSAC and regularization aided least square fitting. Through quantitative evaluation, we verify that the proposed algorithm is capable of multi lane detection with high accuracy in real-time on our own acquired road data.

• Journal of Korean Society of Forest Science
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• v.106 no.2
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• pp.213-218
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• 2017

The purpose of this study was to develop age-biomass model in Chungnam region containing random effect. To develop the biomass model by species and tree component, data for Pinus densiflora in central region is collected to 30 plots (150 trees). The mixed model were used to fixed effect in the age-biomass relation for Pinus densiflora, with random effect representing correlation of survey area were obtained. To verify the evaluation of the model for random effect, the akaike information criterion (abbreviated as, AIC) was used to calculate the variance-covariance matrix, and residual of repeated data. The estimated variance-covariance matrix, and residual were -1.0022, 0.6240, respectively. The model with random effect (AIC=377.2) has low AIC value, comparison with other study relating to random effects. It is for this reason that random effect associated with categorical data were used in the data fitting process, the model can be calibrated to fit the Chungnam region by obtaining measurements. Therefore, the results of this study could be useful method for developing biomass model using random effects by region.

• Journal of Korea Water Resources Association
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• v.48 no.3
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• pp.233-243
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• 2015

The bimodal flocculation of cohesive sediments in water environments describes the aggregation and breakage process developing a bimodal floc size distribution with dense flocculi and floppy flocs. A two class population balance equation (TCPBE) was tested for simulating the bimodal flocculation by a model-data fitting analysis with two sets of experimental data (low and high turbulent flows) from 1-D flocculation-settling column tests. In contrast to the Single-Class PBE (SCPBE), the TCPBE could simulate interactions between flocculi and flocs and the flocculation mechanism by differential settling in a low turbulent flow. Also, the TCPBE could perform the same quality of simulation as the elaborate Multi-Class PBE (MCPBE), with a small number of floc size classes and differential equations. Thus, the TCPBE was proven to be the simplest model that is capable of simulating the bimodal flocculation of cohesive sediments in water environments and water, wastewater treatment systems.

• Journal of Fashion Business
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• v.12 no.6
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• pp.46-60
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• 2008

Lyocell is a regenerated cellulosic fiber manufactured by an environmentally friendly process. The major advantages of lyocell are the excellent drape forming property, the genuine bulkiness, smooth surface, and high dry/wet tenacities. However, one drawback of lyocell is its fibrillation property, which would degrade its aesthetic quality and lower the consumer satisfaction. In our previous studies, lyocell was treated with epichlorohydrin, a non-formalin based crosslinker, to reduce its fibrillation tendency. To investigate the changes of physical properties upon ECH-treatment, the hand characteristics of ECH-treated fabric were observed using KES-FB system and the 3D-virtual sewing image of the fabrics were obtained using 3D CAD simulation system in this study. Since epichlorohydrin(ECH) treatment was conducted in the alkaline medium, the weight reduction was observed in all treated lyocell. The treated lyocell became light, smooth and flexible in spite of ECH crosslinker application. LT and RT in tensile property upon the ECH treatment did not change significantly, however, EMT and WT in the tensile property increased. The significant decrease in bending rigidity was resulted in all ECH-treated lyocell, which is the result of the weight loss upon the alkali condition of ECH treatment. The bending rigidity increased again in the ECH 30% treated lyocell, however, the B value is still lower than the original. Therefore, the ECH-treated lyocell would be more stretchable and softer than the original. Shear rigidity was also decreased in all ECH-treated lyocell, which would result in more drape and body fitting when it is made as a garment. The ECH-treated fabric showed the softer smoother surface according to SMD value from KES evaluation. The virtual 3D sewing image of the ECH-treated lyocell did not show a significant change from that of the original except ECH 30% treated lyocell. ECH 30% treated lyocell showed a stiffer and more puckered image than the original.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.115-121
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• 2010

To evaluate the engineering characteristics of aggregate base materials, cyclic triaxial, CBR and permeability tests were performed for 15 samples. The CBR values of aggregate base materials have wide range from 32 to 110(average 81) and the amount of swelling in submerged conditions has below 0.04mm. The Modulus of aggregate base materials were significantly affected by volumetric stress, linear volumetric model was best for fitting. The modulus of aggregate base materials were determined within range of 100MPa~600MPa, 80~270 and 0.1~0.6 for model coefficient $k_1$ and $k_2$ respectively. The empirical correlation model was suggested that prediction the modulus from the basic properties obtained from particle size distribution test and compaction test. The coefficient of determination of the proposed correlation model was 0.423 for model coefficient $k_1$, 0.920 for model coefficient $k_2$ and 0.872 for modulus with stress level.

• Economic and Environmental Geology
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• v.26 no.2
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• pp.207-215
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• 1993

In modem petroleum reservoir engineering, the characterization of reservoir heterogeneities is very important to accurately understand and predict reservoir production performance. Formation evaluation for the description of reservoir is generally conducted by performing the analysis of well logging, core testing, and well testing. However, the measured data points by well logging or core testing are in general very sparse and hence reservoir properties should be interpolated and extrapolated from measured points to uncharacterized areas. In assigning the data for the unknown points, simple averaging technique is not feasible as optimum estimation method since this method does not account the spatial relationship between the data points. The main goal of this work is to develop PC-version of multi-purpose geostatistical model in which several stages are systematically proceeded. In the development of model, the simulator employs a automatic selection of semivariogram function such as exponential or spherical model with the best values of $R^2$. The simulator also implements a special algorithm for the fitting of semivariogram function to experimental sernivariogram. The special algorithm such as trial and error scheme is devised since this method is much more reliable and stable than Gauss-Newton method. The simulator has been tested under stringent conditions and found to be stable. Finally, the validity and the applicability of the developed model have been studied against some existing actual field data.