• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.1
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• pp.63-69
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• 2000

The high-$T_c$ Superconducting (HTS) antenna which consists of "H" type resonator has the benefits for the miniaturization of antenna in comparison with the microstrip antenna of the similar dimension. To fabricate the "H" type antenna, HTS $YBa_2Cu_3O_{7-x}$ (YBCO) thin films were deposited on MgO substrates using rf-magnetron sputtering. Standard etching processes were performed for the patterning of the "H" type antenna. For comparison between normal conducting antennas and superconducting antennas, the gold antennas with the same dimension were also fabricated. An aperture coupling was used for impedance matching between $50{\Omega}$ feed line and HTS radiating patch. The diverse experimental results were reported in terms of the resonant frequency, the return loss and the characteristics impedance. The "H" type superconducting antenna showed the performance of 1.36 in SWR, 24% in efficiency, and 14.6 dB in the return loss superior of the normal conducting counterpart.

• Journal of Chest Surgery
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• v.28 no.9
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• pp.811-816
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• 1995

Repairs of atrial septal defect utilizing cardiopulmonary bypass were performed in 50 adults, ranging age from 16 to 53 years, since April 1986 up to October 1994. They occupied 38.8% of all adult congenital heart disease operated in the same period. Preoperatively, 16 patients were functional class II, 12 patients class III and 4 patients class IV[New York Heart Association Classification , respectively. Five patients combined with atrial fibrillation and the remainders revealed regular sinus rhythm. Cardiac catheterizations were performed in 43 out of 50 patients, and revealed a systolic pulmonary arterial pressure in excess of 51 mmHg in 4 patients but none had reversed shunt. 40 patients[80% were repaired with patch closure and remainings were repaired with direct closure. 49 patients were followed up for 2 months up to 102 months[average 55 months . A comparison of the preoperative and postoperative functional class demonstrated a mean decrease of one NYHA functional level[2.5$\pm$0.63 to 1.4$\pm$0.56 . There was no operative mortality. One patient died during the follow-up period and the death was unrelated to heart disease. Operative treatment is indicated for repair of atrial septal defect with left to right shunt in the adult patient and a considerable clinical improvement can be anticipitated with low mortality.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.71-80
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• 1987

Twenty six patients were operated a total correction of tetralogy of Fallot between Jan., 1984 and July, 1985 at the Dept. of thoracic and cardiovascular surgery, Chonnam University Medical School, and a comparison between the survived group [n = 18] and the dead group [n = B was performed to detect factors influencing laboratory data, cineangiographic findings, operative findings and methods, and pump time. Following results were obtained, 1. There was no significant difference between two groups in the preoperative P.O2 and hematocrit level. 2. The size of the interventricular defect was not related to the operative mortality. 3. There was a significant difference in mortality rate between combined type of stenosis of pulmonary artery, valve and infundibulum and other types of right ventricular outflow tract stenosis. 4. There was a significant difference in mortality rate between the transannular patch reconstruction and other types of operative procedure. 5. There was no significant difference between two groups in total bypass time and aortic time. 6. There was no significant difference between two groups in left ventricular end diastolic volume and right ventricular end diastolic volume. 7. The operative mortality was related to the ratio of the diameter of the pulmonary valve annulus or each pulmonary artery to the ascending or descending aorta in cineangiographic findings, but there was no statistical significance of which probably is due to the lack of the total number of patients.

• Journal of Chest Surgery
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• v.24 no.8
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• pp.802-806
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• 1991

Primary neoplasms of the ribs and sternum are rare. Most primary bony chest wall neoplasms are malignant, and chondrosarcoma is the most common malignancy in this location The etiology of chondrosarcoma is unknown. Definitive diagnosis of chondrosarcoma can only be made pathologically. The natural history of chest wall chondrosarcoma is one of slow growth and local recurrence. Most tumors of the sternum require wide resection and reconstruction procedures, with potentially serious postoperative problems. Advances in chest wall reconstruction primarily through refinement in muscle transposition and clarification of the functional anatomy and blood supply of trunk muscles, has resulted in a more aggressive resection of the these tumors . Recently we experienced a case with chondrosarcoma of the sternum. A 56 year-old man was admitted to our hospital due to painless, slowly enlarging mass at the left sternoclavicular junctional area. The chest radiograph strongly suggested an underlying cartilaginous neoplasm owing to the appearance of typical flocculent and curvilinear calcifications within the lesion. On CT of the chest, the tumor exhibited a scalloped or lobulated contour, hypodensity of the nonmineralized component in comparison to adjacent muscle, and characteristic stippled cartilaginous matrix mineralization, also typical for cartilaginous neoplasm. The patient underwent wide resection of the chest wall tumor include with a 2-3cm margin of normal tissue on all sides and the thoracic skeletal defect was reconstructed with polytetrafluoroethylene [Gore-Tex] soft-tissue patch. Soft tissue reconstructive procedure was done with the pectoralis major muscle transposition. The patient had an uneventful postoperative course and discharged without adjuvant treatment such as radiation and chemotherapy.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.35-39
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• 2006

With a growing concern about the state of infrastructure worldwide, the demand for the development of reliable nondestructive testing techniques (NDT) is ever increasing. Among possible NDT techniques. microwave method is proven to be effective in fast and non-contact inspection of concrete structures and inclusions inside concrete. It is also found that the microwave method has a potential in detecting the delamination between fiber reinforced polymer (FRP) plate and concrete. On the other hand, ultrasonic method can be another way to find the delamination. In this paper, the research work needed for the development of a reliable microwave method and ultrasonic method is studied in actual measurements of concrete specimens reinforced with FRP. Concrete specimens are made with FRP and artificial delamination inside. A microwave measurement system with horn antennas with high center frequency and broad frequency bandwidth are used to image inside concrete specimens for the detection of debonding. between concrete and FRP. Also, the equipment of ultrasonic method which is commercialized are used at the same condition. Both of the results are analyzed in comparison of each other. Microwave and ultrasonic methods have been used for the detection of debonding between concrete and fiber-reinforced plastic (FRP).

• Journal of Welding and Joining
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• v.23 no.2
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• pp.81-89
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• 2005

A numerical model for multiple reflection effects of a polarized beam on laser grooving has been developed. The surface of the treated material is assumed to reflect laser irradiation in a fully specular fashion. Combining electromagnetic wave theory with Fresnel's relation, the reflective behavior of a groove surface can be obtained as well as the change of the polarization status in the reflected wave field. The material surface is divided into a number of rectangular patches using a bicubic surface representation method. The net radiative flux far these patch elements is obtained by standard ray tracing methods. The changing state of polarization of the electric field after reflection was included in the ray tracing method. The resulting radiative flux is combined with a set of three-dimensional conduction equations governing conduction losses into the medium, and the resulting groove shape and depth are found through iterative procedures. It is observed that reflections of a polarized beam play an important role not only in increasing the material removal rate but also in forming different final groove shapes. Comparison with available experimental results for silicon nitride shows good agreement for the qualitative trends of the dependence of groove shapes on the electric field vector orientation.

• Journal of Chest Surgery
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• v.27 no.3
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• pp.202-208
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• 1994

We reviewed 30 patients with tetralogy of Fallot who had underwent transannular patch reconstruction of the right ventricular outflow tract from January 1990 to May 1993. The patients were divided into two groups according to the approaching pattern for the corrective surgery: 12 patients[aged 11 months to 4 years; mean age, 2.3 years] in transatrial group who were repaired by transatrial-transpulmonary approach; 18 patients[aged 13 months to 6 years; mean age, 3.2 years] in transventricular group who were repaired by transventricular approach. The incidence of postoperative right bundle branch block was not statistically different between two groups. With follow up from 3 months to 32 months after operation, none in transatrial group revealed a remnant RVOT stenosis over 50mmHg or tricuspid regurgitation more than grade II with 2D-echocardiography, but two cases[7.7%] in transventricular group revealed these complications. Early postoperative death was 4 cases[13.3%] which all belonged to transventricular group. In conclusion successful repair of tetralogy of Fallot can be accomplished in most patients by transatrial-transpulmonary approach and we can anticipate better results by this approach in terms of postoperative right ventricular function and arrhythmia than conventional transventricular approach.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4429-4447
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• 2018

Local binary descriptors are well-suited for many real-time and/or large-scale computer vision applications, while their low computational complexity is usually accompanied by the limitation of performance. In this paper, we propose a new optimization framework, RLDB (Robust-LDB), to improve a typical region-based binary descriptor LDB (local difference binary) and maintain its computational simplicity. RLDB extends the multi-feature strategy of LDB and applies a more complete region-comparing configuration. A cascade bit selection method is utilized to select the more representative patterns from massive comparison pairs and an online learning strategy further optimizes descriptor for each specific patch separately. They both incorporate LDP (linear discriminant projections) principle to jointly guarantee the robustness and distinctiveness of the features from various scales. Experimental results demonstrate that this integrated learning framework significantly enhances LDB. The improved descriptor achieves a performance comparable to floating-point descriptors on many benchmarks and retains a high computing speed similar to most binary descriptors, which better satisfies the demands of applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1355-1362
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• 2000

Microstrip antennas are attractive for many applications because of their compact size, low profile, and light weight. Recently, the demand for the miniaturization of the personal communication equipment has been increasing along with the proliferation of personal communication systems. Thus, the development of small antenna has been highly demanded. In this paper, a new technique to reduce the overall dimension of a microstrip antenna with a locally non-homogeneous substrate configuration is proposed. The miniaturized microstrip antenna for a repeater system in a mobile communication cellular band(824~894 MHz) is designed with the proposed technique, and commercialized with low cost, light weight, and small size. Comparison between simulations, based on Agilent Technologies HFSS software, and measurements are provided. The proposed method will be more attractive for a light-weight, small-size, and low-cost microstrip array design. This paper also presents the bandwidth improvement technique for under-coupled microstrip patch antenna with a tuning stub.

• Smart Structures and Systems
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• v.20 no.6
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• pp.657-668
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• 2017

In this research, an active vibration suppression of a smart beam having piezoelectric sensor and actuators is investigated by designing separate controllers comprising a linear quadratic regulator and a neural network. Firstly, design of a smart beam which consists of a cantilever aluminum beam with surface bonded piezoelectric patches and a designed mechanism having a micro servomotor with a mass attached arm for obtaining variations in the frequency response function are presented. Secondly, the frequency response functions of the smart beam are investigated experimentally by using different piezoelectric patch combinations and the analytical models of the smart beam around its first resonance frequency region for various servomotor arm angle configurations are obtained. Then, a linear quadratic regulator controller is designed and used to simulate the suppression of free and forced vibrations which are performed both in time and frequency domain. In parallel to simulations, experiments are conducted to observe the closed loop behavior of the smart beam and the results are compared as well. Finally, active vibration suppression of the smart beam is investigated by using a linear controller with a neural network based adaptive element which is designed for the purpose of overcoming the undesired consequences due to variations in the real system.