• The Journal of the Korea Contents Association
• /
• v.14 no.11
• /
• pp.558-574
• /
• 2014

The number of fatty liver patients is sharply growing due to the rapid increase in the incidence of metabolic syndrome, which can lead to diseases such as abdominal obesity, hypertension, diabetes, and hyperlipidemia. Early diagnosis requires examinations using magnetic resonance imaging (MRI), wherein quantitative analyses are implemented through a professional water-fat separation method in many cases, as the intensity values of the areas of interest and non-interest are considerably similar or the same. However, such separation method generates inaccurate results in high magnetic fields, where the inhomogeneity of the fields increases. To overcome the limits of such conventional fat quantification methods, this paper proposes a field map estimation method that is effective in high magnetic fields. This method generates field maps through echo images that are obtained using the existing IDEAL sequences, and considers the wrapping degree of the field maps. Then clustering is performed to separate calibration areas, the least square fits based on the region growing method schema of the separated calibration areas, and the histograms are adjusted to separate the water from the fats. In experiment results, our proposed method had a superior fat detection rate of an average of 86.4%, compared to the ideal method with an average of 61.5% and Yu's method with an average of 62.6%. In addition, it was confirmed that the proposed method had a more accurate water detection rate of 98.4% on the average than the 88.6% average of the fat saturation method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.1
• /
• pp.52-59
• /
• 2007

A field mill capable of measuring the magnitude and polarity of electric fields at the ground level was studied to apply to a lightning warning system as a sensor. We designed and fabricated a planar-shutter type field mill with a rotating-vanes. A calibration of the field mill was performed in a vertically symmetrical arrangement which consists of two equal size parallel round plates to form a homogeneous electrical fields. The sensitivity of the field mill was adjusted at 0.5[V/kV/m], and this covers a ranges from 200[V/m] to 20[kV/m]. After the calibration experiment, the field mill was installed on the roof of a building to measure the changes of electric field intensity caused by thunderclouds. During the period from July 1. 2006 to July 15. 2006, the electric field intensity was recorded a ranges of $+2[kV/m]{\sim}-6[kV/m]$ depending on generation, extinction and movement of thunderclouds. From the actual test on the ground it is confirmed that the field mill has a good performance necessary for the measurement of DC electric fields.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.43 no.1
• /
• pp.96-107
• /
• 2015

Brownfield sites are beginning to be considered as potentially useful areas for landscape design and planning, with post-industrial areas such as water treatment facilities and military training bases being converted into useful landscapes such as parks and recreation areas. These redevelopments bring broad benefits through revitalizing communities and increasing property values, thus, increasing the demand for comprehensive management and planning policies. This study examines changes in U.S. brownfield policies and programs and, identifies their periodic characteristics over the thirty years since the Superfund program was introduced in 1980. A descriptive and interpretive approach was utilized, focusing specifically on a time sequential analysis of the data gathered from the overview of the Environmental Protection Agency's web-based documents and related literature. The primary changes in and characteristics of programs and policies were analyzed and divided into three periods : environmental protection, remediation and reuse, and comprehensive planning. Four major features were identified: relaxation and readjustment of regulation, diversification of support programs, a mix of top-down and bottom-up approaches, and database system building. The study examines how common brownfield problems such as site identification difficulties and assessment and remediation cost have been dealt with in the regulatory context and has implications for future policies and programs for effective brownfield planning and management in Korea.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.1
• /
• pp.1-8
• /
• 2004

We developed a new PDP gray scale implementation method on the basis of the quantized memory addressing(QMA) principle. We defined three wall charge states; 'fully-on', 'off', and 'half-on', by controlling the width of address pulses. With these three wall charge state, we were able to express 255 level gray scale with only 7 sub-fields. Furthermore, in contrast to the conventional driving methods, the sub-field combinations for any two adjacent gray levels differ by only 1 sub-field, at worst, and therefore, eliminate the dynamic false contours. Since this method use 7 sub-field, the sustain discharge Period is increased by more than $70\%$ compared to the 12 sub-field method which reduces the dynamic false contours.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.2
• /
• pp.227-233
• /
• 2001

Electromagnetic field characteristics of Reverberation chamber, which could be applicable for an alternative test facility of electromagnetic interference and radiated electromagnetic susceptibility have been investigated. To obtain the required field uniformity of reverberation chamber, Schroeder method Quadratic Residue Diffuser was designed to be applied to chamber. In this paper, 3 different types of diffusers depending on diffuser's periodic direction have been used to investigate field characteristics of each type by using FDTD numerical method. The results show all 3 types of reverberation chambers have below $\pm$3 dB tolerance of field uniformity characteristics, and the symmetrical, type 3, structure show better results among them.

• Journal of Broadcast Engineering
• /
• v.5 no.2
• /
• pp.140-158
• /
• 2000

Testing of terrestrial Digital TV(DTV) broadcasting in Seoul and Kyung-gi region was started in May 1999. Tasks of the committee for DTV technical evaluation were to implement test procedures for DTV transmitting systems, to analyze various technical aspects of DTV and to complete a field test. This paper summarizes the field test results. The field test vehicle was designed and constructed to measure field data. We chose over 200 test points to verify the receiving status of DTV signals and compared them with the analog TV signals at the same site. The results showed stable and satisfactory reception of DTV signals over 70%. The system performance index was over 80%.

• Journal of Biomedical Engineering Research
• /
• v.16 no.3
• /
• pp.337-344
• /
• 1995

Because of the high energy of the treatment beam, contrast of portal films is very poor. Many image processing techniques have been applied to the portal images but a significant drawback is the loss of definition on the edges of the treatment field. Analysis of this problem shows that it may be remedied by separating the treatment field from the background prior to enhancement and uslng only the pixels within the field boundary in the enhancement procedure. A new edge extraction algorithm for accurate extraction of the radiation field boundary from portal Images has been developed for contrast enhancement of portal images. In this paper, portal image segmentation algorithm based on Sobel filtration, labelling processes and morphological thinning has been presented. This algorithm could automatically search the optimal threshold value which is sensitive to the variation of the type and quality of portal images.

• The Journal of Information Technology
• /
• v.7 no.2
• /
• pp.43-54
• /
• 2004

Since Dr. John J. Hopfield has proposed the HOpfield network, it has been widely applied to the pattern recognition and the routing optimization. The method of Jian-Hua Li improved efficiency of Hopfield network which input pattern's weights are regenerated by SVD(singluar value decomposition). This paper deals with Li's Hopfield Network by linear pre-processing. Linear pre-processing is used for increasing orthogonality of input pattern set. Two methods of pre-processing are used, Hadamard method and random method. In manner of success rate, radom method improves maximum 30 percent than the original and hadamard method improves maximum 15 percent. In manner of success time, random method decreases maximum 5 iterations and hadamard method decreases maximum 2.5 iterations.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.2
• /
• pp.81-87
• /
• 1999

In this research, we propose a field mismatch compensation method for interlaced scan image and a image restoration technique for removing motion blur. In order to compensate field mismatch, the edge classification-based linear interpolation technique and the method using the object-based motion compensation are described. We also propose an edge estimation method and an motion-based image segmentation algorithm. For removing motion blur, we adopt an adaptive iterative image restoration method using the motion-based segmentation result to improve the quality of restored image.

• Communications for Statistical Applications and Methods
• /
• v.16 no.6
• /
• pp.925-936
• /
• 2009

There very many approaches to impute missing values in the iid. case. However, it is hardly found the imputation techniques in the Markov random field(MRF) case. In this paper, we show that the imputation under MRF is just to impute by fitting the normal mixture model(NMM) under several practical assumptions. Our multivariate normal mixture model based approaches under MRF is applied to impute the missing pixel values of 3-variate (R, G, B) color image, providing a technique to smooth the imputed values.