• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.100-109
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• 2001

The backscattered sound energy by fish depends on size and physical structure and, most important, on the presence or absence of a swimbladder. Target strength experiments of red seabream (Pagrus major) were conducted by using 38 (split-beam), 120 (split-beam) and 200 kHz (dual-beam) frequencies with live fishes confined in a net-cage and free swimming in tank without the cage, respectively. For 38, 120, and 200 kHz frequencies, target strength equations are expressed as a function of fish length：TS/sub 38kHz/=20 log/sub 1o(l)/-66.41, TS/sub 120kHz/＝20 log/sub 1o(1)/-71.80, and TS/sub 200kHz/＝20 log/sub 1o(1)/-73.94. To test the acoustic models by using Helmholtz-Kirchhoff ray approximation, predictions of target strength based on swimbladder morphometries are compared with target strength measurements. The target strength of whole fish depends on variations in swimbladder morphology than fish body morphology. In the mean time, when the fish is confined in the net cage, scattering length by the backscattered signal matched with the Gaussian PDF, while under the free-swimming condition, scattering length is close to the Rayleigh PDF.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.89-94
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• 2006

Purpose : To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. Materials and Methods : One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed; 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7 mm slice thickness. Conclusion : The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.

• The Journal of the Acoustical Society of Korea
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• v.32 no.2
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• pp.104-115
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• 2013

In a shallow water waveguide, reverberation signals and their Doppler effects form the primary limitation on sonar system performance. Therefore, in the reverberation-limited environment, it is necessary to estimate the reverberation level to be encountered under the conditions in which the sonar system is operated. In this paper, high-frequency reverberation model capable of simulating the reverberation signals received by a high-speed moving source in a range independent waveguide is suggested. In this model, eigenray information from the source to each boundary is calculated using the ray-based approach and the optimizing method for the launch angles. And the source receiving position changed by the moving source is found by a scattering path-finding algorithm, which considers the speed and direction of source and sound speed to find the path of source movement. The scattering effects from sea surface and bottom boundaries are considered by APL-UW scattering models. The model suggested in this paper is verified by a comparison to the measurements made in August 2010. Lastly, this model reflects well statistical properties of the reverberation signals.

• Journal of Haehwa Medicine
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• v.12 no.1
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• pp.79-102
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• 2003

It has been believed that the human body can be effected by color, sound, smell, and taste - each of them is based on the original character. Out of these elements, the color can be a mediation that absorbs energy into human body and adapts it to the creatures whose life are definitely based on the solar energy. This thesis makes a study of the possibility of applying the color to the oriental medical science by researching the color psychology and therapy which are studied in the west medical science, the recognition and application of color developed from orientalism, and the opinion of color in the oriental medical science. Color therapy is one of the psychological treatment techniques that are able to recover and maintain the health with the rays of the sun rays and the color. The light and the color have its energy that may relax, harmonize, encourage, or excite a human being. This is because the wavelength and the vibration of each color will take effects to human body. The core energy of absorbing and distributing the color vibration is made in the 7 "chakras" in the body, which are the pith and marrow of bio-energy directly connected with the center of the nervous system. There are several methods in the color therapy - the treatment of solar ray, the color-bath, the water-therapy using color energy, the inducement of the solar energy into the body, the acupuncture, the therapy of crystal and jewel, and the self-suggestion dependent upon the color. The color therapy can help us to keep our balance by changing the emotion into the positive energy that will cure the disease with color. As a result, this method not only must be useful to cure physical disease, or develop into good health but also will be used in conforming itself to the mental disease. The color therapy mainly uses the eight colors, which are made by mixing Red, Yellow and Blue basic colors in the field. They are never used in the treatment, but they will go along with complementary colors. This rule is closely connected with the theory of yin and yang which lies at the root of oriental philosophy, and with the treatment principle of oriental medical science whose field is focused on the balancing the body mentally as well as physically. In the East, it is the Obangsaek - the color of blue, red, yellow, white, and black in the theory of yin and yang and the five elements that have been used in helping people having trouble with their health for a long time. In the view of the oriental medical science, these five colors attached the theory of five-elements have been very useful to the physiology, the pathology, or the diagnosis, and been applied to the medical treatment, combining themselves with a five-taste in medicinal herbs. Since the study of color and human physiology has been made in some different interest and fields these days, it goes to prove that the different function of color we couldn't have got before becomes very useful to the medical science. The color must be worth researching the diversity for applying itself to the oriental medical science.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.13.3-14
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• 1983

A clinical study was done on 24 cases with foreign body in the air passage, who were treated at the department of otolaryngology of Kyung Hee university hospital during the period from Apr. 1973 to Feb. 1983. The obtained results were as follows : 1) The incidence of sex was much higher in male than female and children under 4 years old were predominant. 2) Almost of all patients came in the hospital within 3 days after onset. However one patient came in hospital 5 months later. 3) The variety of foreign body was numerous, among which vegetables and plastic materials were most frequently found. 4) The most common sites of lodgement were trachea and right main bronchus. 5) The common clinical manifestations were dyspnea, decreasing breathing sound and cough. Negative X-ray findings did not exclude a foreign body in the air passage. 6) The important pulmonary complications due to foreign body were atelectasis, emphysema and pneumonia. 7) Foreign body was successfully removed by use of peroral or inferior endoscopy in all cases except one case, on whom thorachotomy was done. 8) The important complications due to the surgical procedure were decannulation difficulty and pneumothorax.

• Journal of the Korea Society for Simulation
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• v.30 no.1
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• pp.11-20
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• 2021

As unmanned underwater systems have recently emerged, a high-speed underwater channel modeling technique, which is one of the most important techniques in the system, has received a lot of attention. In this paper, we proposed a high-speed sound propagation model and verified the applicability through quantitative performance analyses. We used a high-order finite difference method (FDM) for wave propagation modeling in the water, and a domain decomposition method was adopted using multiple general-purpose graphics processing units (GPUs) to increase the calculation efficiency. We compared the results of the model we proposed with the analytic solution in the half-infinite media and results of the Virtual Timeseries Experiment (VirTEX) model, which is based on the ray method. Finally, we analyzed the performance of the model quantitatively using numerical examples. Through quantitative analyses of the improvement in computational performance, we confirmed that the computational speed increases linearly as the number of GPUs increases. The computation times are increased by 2 times and 8 times, respectively, when the domain size of computation and the maximum frequency are doubled. We expect that the proposed high-speed underwater channel modeling technique is able to contribute to the enhancement of national defense as an underwater communication channel model and analysis tool to develop the underwater communication technique for the unmanned underwater system.

• Tuberculosis and Respiratory Diseases
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• v.49 no.6
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• pp.774-779
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• 2000

Pseudomembranous colitis, although uncommon, is an important complication of antibiotics that is related to a variety of deleterious effects on the gastrointestinal tract. Rifampicin is one of the 1st line agents in the treatment of tuberculosis and a large number of patients are exposed to its potential adverse effects. We report upon a patient that had diarrhea due to pseudomembranous colitis after receiving antitubeculous medication, and which was probably caused by rifampicin. A 77-year-old man was admitted with diarrhea of three weeks duration. One month previously, he suffered from left pleuritic chest pain and left pleural effusion was noticed at chest X-ray. One week prior to the onset of diarrhea, he was started on empirically isoniazid, rifampicin, ethambutol and pyrazynamide as antituberculous medication. On admission, he complained of diarrhea, left pleuritic chest pain, dyspnea and sputum. On physical examination, breathing sound was decreased in the left lower lung field and bowel sound increased. Pleural biopsy revealed chronic granulomatous inflammation, which was compatible with tuberculosis, Sigmoidoscopy showed whitish to yellowish pseudomembrane with intervening normal mucosa, and his stool was positive for C.difficle toxin. He was diagnosed as pseudomembranous colitis and treated with oral metronidazole and vancomycin. The diarrhea did not recur after reinstitution of the anti-tuberculous medication without rifampicin inpatients with severe diarrhea receiving anti-tuberculous medication, rifampicin induced pseudomembranous colitis should be excluded.

• Clinical and Experimental Pediatrics
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• v.48 no.8
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• pp.832-838
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• 2005

Purpose : Mycoplasma pneumoniae infection is relatively common in childhood. Its extrapulmonary manifestations have been reported so much, but hepatitis associated with it has been reported rarely in Korea. Methods : A clinical study was performed on 556 patients of M. pneumoniae pneumonia diagnosed serologically at Gil hospital from January 2001 to December 2004. We reviewed 65 cases among these patients, who had elevated level of serum AST and ALT greater than 50 IU/L respectively without evidence of hepatitis A, B, C, Cytomegalovirus and Ebstein-Barr virus infections. Results : Hepatitis occurred in 11.7% of Mycoplasma pneumoniae pneumonia, especially in fall and winter times. Male to female ratio was 1.2 : 1 and the mean age was 4 years and 3 months. Besides hepatitis, cough(95.4%), sputum(52.3%) and dyspnea(12.3%) were common as pulmonary manifestations. And among gastrointestinal manifestations, nausea/vomiting(26.2%) was the most common symptom, followed by poor oral intake(12.3%), diarrhea(12.3%) and abdominal pain(6.2%). In addition to hepatomegaly(4.6%) and splenomegaly(4.6%), coarse breathing sound was the most common physical manifestation, followed by rale(63.1%), pharyngeal injection(26.2%), and rash(10.8%). Anemia was noted in 20.0%, neutrophilia in 10.8%, eosinphilia in 38.5% and thrombocytosis in 6.2%, respectively. Mean level of ESR and CRP was 32.02 mm/hr and 6.69 mg/dL, respectively. Mean level of AST and ALT was 293.80 IU/L and 181.48 IU/L, respectively. Hyperbilirubinemia was noted in 7.7% and hypoalbuminemia was noted in 58.5%. Lobar or lobular pneumonia(78.5%) was the most common finding in chest X-ray and left lower lobe(39.2%) was most commonly affected. Pleural effusion was noted in 26.2%. Mean duration of hospitalization was 9.91 days. Serum AST/ALT level was normalized within 9.94 days and pulmonary consolidation resolved within 14.29 days. Conclusion : The prognosis of M. pneumoniae hepatitis is good. However, liver function should be considerately checked in M. pneumoniae infection because its incidence is not so low.