• The Journal of Engineering Geology
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• v.14 no.1
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• pp.29-46
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• 2004

It is important to identify geometries of fracture that act as a conduit of fluid flow for characterization of ground water flow in fractured rock. Fracture geometries control hydraulic conductivity and stream lines in a rock mass. However, we have difficulties to acquire whole geometric data of fractures in a field scale because of discontinuous distribution of outcrops and impossibility of continuous collecting of subsurface data. Therefore, it is needed to develop a method to describe whole feature of a target fracture geometry. This study suggests a new approach to develop a method to characterize on the whole feature of a target fracture geometry based on the Fourier transform. After sampling of specimens along a target fracture from borehole cores, effective frequencies among roughness components were selected by the Fourier transform on each specimen. Then, the selected effective frequencies were averaged on each frequency. Because the averaged spectrum includes all the frequency profiles of each specimen, it shows the representative components of the fracture roughness of the target fracture. The inverse Fourier transform is conducted to reconstruct an averaged whole roughness feature after low pass filtering. The reconstructed roughness feature also shows the representative roughness of the target subsurface fracture including the geometrical characteristics of each specimen. It also means that overall roughness feature by scaling up of a fracture. In order to identify the characteristics of permeability coefficients along the target fracture, fracture models were constructed based on the reconstructed roughness feature. The computation of permeability coefficient was performed by the homogenization analysis that can calculate accurate permeability coefficients with full consideration of fracture geometry. The results show a range between $10^{-4}{\;}and{\;}10^{-3}{\;}cm/sec$, indicating reasonable values of permeability coefficient along a large fracture. This approach will be effectively applied to the analysis of permeability characteristics along a large fracture as well as identification of the whole feature of a fracture in a field scale.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.2
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• pp.135-145
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• 2020

Wave observation is widely used to direct observation method for observing the water surface elevation using wave buoy or pressure gauge and remote-sensing wave observation method. The wave buoy and pressure gauge can produce high-quality wave data but have disadvantages of the high risk of damage and loss of the instrument, and high maintenance cost in the offshore area. On the other hand, remote observation method such as radar is easy to maintain by installing the equipment on the land, but the accuracy is somewhat lower than the direct observation method. This study investigates the data quality of MIROS Wave and Current Radar (MWR) installed at Dokdo and improve the data quality of remote wave observation data using the wave buoy (CWB) observation data operated by the Korea Meteorological Administration. We applied and developed the three types of wave data quality control; 1) the combined use (Optimal Filter) of the filter designed by MIROS (Reduce Noise Frequency, Phillips Check, Energy Level Check), 2) Spike Test Algorithm (Spike Test) developed by OOI (Ocean Observatories Initiative) and 3) a new filter (H-Ts QC) using the significant wave height-period relationship. As a result, the wave observation data of MWR using three quality control have some reliability about the significant wave height. On the other hand, there are still some errors in the significant wave period, so improvements are required. Also, since the wave observation data of MWR is different somewhat from the CWB data in high waves of over 3 m, further research such as collection and analysis of long-term remote wave observation data and filter development is necessary.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.4
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• pp.218-234
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• 2004

Recent warm winters were evaluated for a possible shifting of the northern limit for winter barley cultivation in Korea. Therefore, safe zones for winter barley cultivation were reclassified based on the average and minimum January air temperature in recent years. The results are as follows: By analysis of mean values of January average air temperatures for 30 years (1971-2000), the northern limits for safe cultivation of hulled, naked, and malting barley were Ganghwa - Icheon - Chungju - Chunyang - Goseong, Cheonan - Geumsan - Mungyeong - Andong - Sokcho, and Gwangju - Jangheung - Sancheong - Pohang - Uljin lines, respectively. Meanwhile, based on the January average air temperature of 14 years (1987-2000) with warmer winters, the safe cultivation zone of winter barley shifted northward of the normal (1971-2000). So, the northern limits for hulled, naked, and malting barley were Pocheon - Chuncheon - Wonju - Yangpyeong - Chunyang, Ganghwa - Icheon - Chungju - Uiseong - Goseong, and Gunsan - Suncheon - Jinju - Miryang - Yeongdeok - Uljin lines, respectively. Winter barley cultivars with the strongest tolerance to low temperature can be grown up to the adjacent areas of Taebaek Mountains (that is, Inje, Hongcheon, Jecheon, and Taebaek areas). Based on January mean air temperatures of 10-year return period for 30 years (1971-2000), the northern limits for hulled and naked barley were Boryeong - Namwon - Geochang - Gumi - Goseong and Seocheon - Jeongeup - Hapcheon - Yeongdeok - Sokcho lines, respectively. It ~ppears that malting barley can be cultivated only at southern coastal areas (that is, Busan, Tongyeong, Yeosu, and Wando areas). On the other hand, based on the weather conditions of 14 years (1987-2000) with warmer winters, the northern limits for hulled, naked, and malting barley were Ganghwa - Icheon - Yeongju - Goseong, Seosan - Namwon - Mungyeong - Andong - Sokcho, and Gwangju - Jangheung - Sacheon - Ulsan - Uljin lines, respectively. The northern limit for winter barley cultivars including Olbori with the strongest tolerance to low temperature was the Ganghwa - Wonju - Chungju - Chunyang - Goseong line.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6099-6111
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• 2015

This study was a systematic review and meta-analysis comparing the effects of aquatic exercise and land-based exercise in the treatment of knee osteoarthritis. 7 studies (n=449) met selection and exclusion criteria out of 287 potential studies obtained from the literature search via Ovid-Medline, Cochrane Library CENTRAL, CINAHL, RISS and KISS. The overall risk of bias of selected studies using SIGN (Scottish Intercollegiate Guidelines Network) checklist for randomized controlled trials (RCT) was regarded as low. As a result of meta analysis, Standardized Mean Difference (SMD) for pain was -0.26(95% CI -0.49, -0.03, p=0.03, $I^2=14%$), which implies that aquatic exercise groups had significant less pain than land-based exercise groups. On the other hand, there was no significant difference between aquatic exercise groups and land based exercise groups for flexion Range of Motion (ROM) (-0.12, 95% CI -0.51, 0.27, p=0.53, $I^2=0%$), extension ROM (-0.04, 95% CI -0.55, 0.48, p=0.89, $I^2=43%$), physical function (-0.12, 95% CI -0.44, 0.19, p=0.44, $I^2=0%$), Quality of Life (QOL) (-0.15, 95% CI -0.54, 0.24, p=0.46, $I^2=0%$). This study has some limitations due to few RCTs comparing aquatic exercise groups and land-based exercise groups in the treatment of knee osteoarthritis. Therefore, further RCTs should be conducted along with long-term outcomes.

• Journal of Chest Surgery
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• v.34 no.10
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• pp.787-791
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• 2001

Coronary artery aneurysm is a rare disorder. It is defined as abnormal dilatation of coronary artery with diameter exceeding 1.5 times the adjacent normal segments. The incidence of coronary aneurysm is 2.6% in Caucasians and 0.25% in Asians. Over half of the former were associated with atherosclerotic coronary artery disease. However, 70 percents of the latter were nonobstructive coronary artery aneurysms. Coronary artery fistula is a rare disorder. It has been identified in only 0.2% of routine cardiac angiographic studies conducted over a 10-year period. The clinical spectrums are various, asymtomatic, asymptomatic murmur, dyspnea on exertion, fatigue, and congestive heart failure. The right coronary artery (56%) and left coronary artery(36%) are mainly involved in the origin site of congenital coronary artery fistula. The draining site of fistula are right ventricle(39%), right atrium(33%), and pulmonary artery(20%) and so on. This 54 years-old woman had intermittent chest tightness and an abnormal mediastinal shadow on chest roentgenogram and chest C-T examination, which was diagnosed as a mediastinal mass such as teratoma. We performed the operation under left anterolateral thoracotomy for mass excision. However, we knew the mass had the pulsating arterial blood flow through a fine needle puncture of the mass and that it was attached to the left ventricle. We believed the excision of mass on beating heart would be very dangerous. Therefore, we closed the wound without excising the mass. After several days, we performed an echocardiography and coronary angiography, We knew it was cardiac tumor. Incidentally, the patient had a tortuous coronary fistula from the right coronary artery to pulmonary trunk. Using cardiopulmonary bypass with moderate systemic hypothermia, the mass was resected and the fistula was clipped with surgical clips. Pathology of the specimen was a giant coronary arterial aneurysm.

• Journal of Chest Surgery
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• v.37 no.5
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• pp.410-415
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• 2004

Background: In the operation for coronary artery stenosis, the procedures for mitral regurgitation are restricted to cases of more than moderate mitral regurgitation or for the lesions in leaflets. This is based on the belief that the less than mild regurgitation are a form of reversible change results from ischemia with coronary artery stenosis. We studied the changes and prognostic factors of mitral regurgitation in patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone. Material and Method: We reviewed the medical records of 90 patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone by a single surgeon from Jan. 1995 to Dec. 2002, We grouped the patients according to the postoperative changes of mitral regurgitation, and then we statistically compared the findings of echocardiogram between preoperative and last follow up. Result: There were 24 cases with progression of mitral regurgitation, 12 cases without changes, 54 cases with improvements of mitral regurgitation in total 90 patients. The bypass to LAD was proven as the significant prognostic factor of mitral regurgitation. The preoperative end diastolic left ventricular volume index were higher in aggravated group with 105.38$\pm$38.89 $m\ell$ compared to 71.75$\pm$28,45 $m\ell$ in improvement group, and 84.00$\pm$11.66 $m\ell$ in no change group. The grade of preoperative mitral regurgitation did not show significant differences among the groups. Conclusion: The mitral regurgitation in patient with coronary artery stenosis can be improved after the coronary artery bypass surgery alone. However, the expectation of improvements based on the degree of preparative mitral regurgitation can not be justified, therefore, the procedures for mitral regurgitation should be aggressively considered even in the cases of mild mitral regurgitation. Also, further study should be performed to identify the exact prognostic factors of mitral regurgitation including the left ventricular volume index, and whether the left anterior descending artery has been bypassed.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.414-419
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• 2007

Background: Replacing the ascending aorta is a standard surgical option for treating acute type A aortic dissection. But replacing the aortic arch has recently been reported as an acceptable procedure for this disease. We compared the effects of aortic arch replacement for treating acute type A aortic dissection with the effects of ascending aortic replacement. Material and Method: From 2002 to 2006, 25 patients undewent surgical treatment for acute type A aortic dissection, 12 patients undewent ascending aortic replacement and 13 patients underwent aortic arch replacement. Among the aortic arch group, an additional distal stent-graft was inserted during the operation in 5 patients. 19 patients (11 arch replaced patients and 8 ascending aortic replaced patients) were followed up at the out patient clinic for an average of $756{\pm}373$ days. All the patients undewent CT scanning and we analyzed their distal aortic segments. Result: 4 patients who underwent ascending aortic replacement died, so the overall mortality rate was 16%. Among the 11 long term followed-up arch replacement patients, 2 patients (18.1 %) developed distal aortic dilatation and one of them underwent thoracoabdominal aortic replacement later on. However, among the 8 the ascending aortic replaced patients, 5 patients (62.5%) developed distal aortic dilatation. Conclusion: Aortic arch replacement is one of the safe options for treating acute type A aortic dissection. Aortic arch replacement for treating acute type A aortic dissection could contribute to a reduced distal aortic dilatation rate and fewer secondary aortic procedures.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.420-427
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• 2007

Background: Postpneumonectomy empyema (PPE) due to bronchopleural fistula (BPF) can be a surgical challenge for surgeons. We analyzed the follow-up outcomes after performing omentopexy and thoracoplasty for the treatment of PPE with BPF after pneumonectomy. Material and Mehod: Between December 1991 and January 2006, 9 patients underwent BPF closure using an omental pedicled flap for the treatment of PPE with BPF after pneumonectomy. There were 7 males and 2 females (mean age: $45.9{\pm}9$ years). The patients were followed up for a mean of 58 months (median: 28 months, range: $6{\sim}169$). When we performed omentopexy, the surgical procedures for empyema were thoracoplasy for 8 patients and the Clagett procedure for 1 patient. Thoracoplasty was performed for the latter patient due to recurrence of empyema, Result: For the 8 patients who were treated by omentopexy and thoracoplasty, there was 1 operation-related death due to sepsis. During follow up, 1 patient, who was treated by omentopexy and a Clagett procedure, died of acute hepatitis 40 months postoperatively. The early mortality was 11.1% (8/9). Of the 8 patients, including the 1 late death patient, successful closure of the BPF were achieved in all patients (8/9) and the empyema was cured in 7 patients (7/8). Conclusion: The BPF closure using an omental pedicled flap was an effective method for treating PPE with BPF due to 75-destroyed lung, and thoracoplasty with simultaneous omentopexy was effective and safe for removing dead space if the patient was young and in a good general condition.

• The Korean Society of Law and Medicine
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• v.16 no.2
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• pp.159-193
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• 2015

Owing to causes such as population aging, increased use of various medical devices, long-term hospitalization of various patients with reduced immune function such as cancer, diabetes, and organ transplant patients, and the growing size of hospitals, hospital infections are continuing to increase. As seen in the MERS crisis of 2015, hospital infections have become a social and national problem. In order to prevent damage due to such hospital infections, it is necessary to first strictly implement measures to prevent hospital infections, while, on the other hand, providing proper relief of damage suffered due to hospital infections. However, the mainstream attitude of judicial precedents relating to hospital infection cases has been judged to in fact shift responsibility over damages due to hospital infections on the patient. In light of the philosophy of the damage compensation system, whose guiding principle if the fair and proper apportionment of damages, there is a need to seek means of drastically relaxing the burden of proof on the patient's side relative to conventional legal principles for relaxing the burden of proof, or the theory of de facto estimation. In relation to such need, the German civil code (Burgerliches Gesetzbuch), which defines contracts of medical treatment as typical contracts under the civil code, and has presumption of negligence provisions stipulating that, in cases such as hospital infections which were completely under the control of the medical care providers, if risks in general medical treatment have been realized which cause violations of the life, body, or health of patients, error on the part of the person providing medical care is presumed, was examined. Contracts of medical treatment are entered into very frequently and broadly in the everyday lives of the general public, with various disputes owing thereto arising. Therefore, it is necessary to, by defining contracts of medical treatment as typical contracts under the civil code, regulate the content of said contracts, as well as the proof of burden when disputes arise. If stipulations in the civil code are premature as of yet, an option may be to regulate through a special act, as is the case with France. In the case of hospital infection cases, it is thought that 'legal presumption of negligence' relating to 'negligence in the occurrence of hospital infections,' which will create a state close to equality of arms, will aid the resolution of the realistic issue of the de facto impossibility of remedying damages occurring due to negligence in the process of occurrence of hospital infections. Also, even if negligence is presumed by law, as the patient side is burdened with proving the causal relationships, such drastic confusion as would occur if the medical care provider side is found fully liable if a hospital infection occurs may be avoided. It is thought that, alongside such efforts, social insurance policy must be improved so as to cover the expenses of medical institutions having strictly implemented efforts to prevent hospital infections in the event that they have suffered damages due to a hospital infection accident, and that close future research and examination into this matter will be required.

• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.276-284
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• 2000

Purpose: We investigated the operative outcome after bypass surgery in patients selected using viability criteria on F-18 FDG PET. Materials and Methods: Rest-24hr delay redistribution imaging of Tl-201 SPECT and F-18 FDG PET were performed in 11 patients. Seven of these 11 patients (6 men, 1 woman) were evaluated to have viable myocardium by F-18 FDG PET. Changes in symptoms and left ventricular ejection fraction (LVEF) after operation were evaluated. Results: In seven of 11 patients, a significant amount of viable myocardium was found on F-18 FDG PET and Tl-201 SPECT. Severity of both chest pain and dyspnea improved markedly in all patients. Mean LVEF improved from 22% to 32%. Conclusion: F-18 FDG PET could be used to select the patients who will benefit from coronary artery bypass surgery.