• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.4
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• pp.54-63
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• 2022

A 3-tonf class liquid rocket engine that powers the upper stage of a small launcher and lifts 500 kg payload to 500 km SSO is designed. The small launcher is to utilize the flight-proven technology of the 75-tonf class engine for the first stage. A combination of liquid oxygen and liquid methane has been selected as their cryogenic states can provide an extra boost in specific impulse as well as enable a weight saving via the common dome arrangement. An expander cycle is chosen among others as the low-pressure operation makes it robust and reliable while a specific impulse of over 360 seconds is achievable with the nozzle extension ratio of 120. Key components such as combustion chamber and turbopump are designed for additive manufacturing to a target cost. The engine system provides an evaporated methane for the autogenous pressurization system and the reaction control of the stage. This upper stage propulsion system can be extended to various missions including deep space exploration.

• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.293-301
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• 2019

Soft tissue masses of the extremities and torso are a common problem encountered by orthopaedic surgeons. Although these soft tissue masses are often benign, orthopaedic surgeons need to recognize the key features differentiating benign and malignant masses. An understanding of the epidemiology and clinical presentation of soft tissue masses is needed to develop a practical approach for evaluation and surgical management. Size and depth are the two most important factors on which triage decisions should be based. In a differential diagnosis of a tumor, it is important to know the characteristics of the soft tissue mass through detailed history taking and physical examinations before the diagnostic procedures. A variety of imaging studies, such as simple radiography, ultrasound, magnetic resonance imaging, positron emission tomography, computed tomography, bone scan, and angiography can be used to diagnose tumors. Know the ledge of advantages and disadvantages of each imaging study is essential for confirming the characteristics of the tumor that can be observed in the image. In particular, ultrasonography is convenient because it can be performed easily in an outpatient clinic and its cost is lower than other image studies. On the other hand, the accuracy of the test is affected by the skill of the examiner. A biopsy should be performed to confirm the tumor and be performed after all imaging studies have been done but before the final treatment of soft tissue tumors. When a biopsy is to be performed, careful attention to detail with respect to multidisciplinary coordination beforehand, cautious execution of the procedure to minimize complications, and expedient follow-up and referral to a musculoskeletal oncologist when appropriate, are essential.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.1
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• pp.219-227
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• 2017

Current military command information system uses electronic equipment a lot on which semiconductor chip is attached. It seems its' importance will increase more with latest information communication technology developing. Electronic equipment which uses electricity contains regular tolerance to high output electric signal. And EMC specification is the standardized of this electronic equipment's tolerance. On the other hand, the Institute of Atomic Energy Research has ever declared that high output electromagnetic pulse(EMP) will be broken out within the radius of 170Km when 10kt nuclear explosion occurs at an altitude of 40Km above Seoul. Then, the region suffer from the damage of most electronic equipments. Therefore, the norm to protect the influences in that case is defined by EMP protection specification. Most common electronic equipments meet the EMC norm, but there is no way to check whether they meet the EMP norm or not. That is because it is difficult to check whether they meet EMP protection norm and is on the matter of cost. Except inevitable cases, there is no review of checking whether they meet the norm or not. Considering the above, in this research, we speculate about the measures to improve military EMP protection ability by analyzing the EMC-EMP correlation and checking the EMP protection ability of general electronic equipment through the analysis.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.3
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• pp.88-103
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• 2023

With the recent advancement of 4th Industrial Revolution technology, transportation systems are generating large amounts of mobility data related to the individual movement trajectories of vehicles and people. There are many constraints on utilizing mobility data containing personal information. Thus, in South Korea, the processing and generation of pseudonymized information and the analysis and utilization of this information have been managed in a dual manner by applying separate agencies and technologies through the revision of the Data 3 Act and the enactment of the Data Basic Act. However, this dual approach fails to securely support the entire data lifecycle and suffers from inefficiencies in terms of processing time and cost. Therefore, to compensate for the problems of the existing Expert Data Combination System and Data Safety Zone, this study proposes an Integrated Data Safety Zone Framework that integrates and unifies the process of generating, processing, analyzing, and utilizing mobility data. The integrated process for data processing was redesigned, and common requirements and core technologies were derived. The result is an architecture for a next-generation Integrated Data Safety Zone system that can manage and utilize the entire life cycle of mobility data at one stop.

• Journal of the Korean Society of Food Culture
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• v.25 no.3
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• pp.251-261
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• 2010

This paper examines the dining tendencies of Koreans toward meat dishes and their related factors, with 301 people residing in Korea as subjects. We questioned this population on their restaurant choices, eating habits, preferences and a dislike with respect to method of cooking. All age groups, with the exception of 50~60 year-olds, were found to consume meat dishes in specialized restaurants. The selection factor for restaurants varied, depending on the age group: affordable cost was the most important factor for whom under 20 year-old. Whereas 20-40 year-old people considered taste and ambience the most for choosing restaurant. The 50-60 year-old people found to seek for convenient restaurant. In terms of the most preferred parts of beef, 20-30 year-old people preferred tenderloin (42.3%) while 40-60 year-old people preferred sirloin (45.6% and 41.2% each). All the other age groups preferred ribs the most (It was also found that) men preferred the rib parts and women preferred tenderloin. With respect to pork, all age groups preferred pork belly, with the highest response rate in the under 20 age group. When consuming meat dishes, 91.0% of respondents pointed to roasting as the most frequent preparation method, the reason being good taste was deemed the highest number of responses. In a survey on preference for stewed meats, 74.8% of the sample pool was found to prefer stew dishes but 24.9% of respondents provided negative answers, the reason for dislike was found to be poor taste for women, and both a long preparation time and poor taste for men. In fact, regardless of marital status, a high number of responses were given for poor taste as the reason for disliking stew dishes. Based on the examined factors for inconveniences in preparing meat dishes, the most common inconvenience factor was the odor of meat left on clothes after the dining experience, followed by the smoke generated in roasting meat, and the safety risk involved with changing the grill. In terms of stir fry preparation, the negative thoughts were due to the splashing of food and spices while cooking, followed by the meat odor left on clothes after dining experience, and the sanitation level of the cooking containers. For deep frying the sanitation level of cooking containers was the biggest reason for dislike, followed by splashing of food when preparing. Lastly, it was indicated that the problem of steaming method was a difficulty of judging the portion, on the top of this, people found that the sanitation level of cooking container and a long preparation time were also the problem of this cooking method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.249-258
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• 2008

Korean engineering firms need to improve their performance in order to stay competitive in the globalize environments which has been led by some international movements including World Trade Organization (WTO) and Free Trade Agreements (FTA). There have been various activities and researches focusing on how to improve competitiveness of Korean engineering firms and the out-of-fashion Engineering Project Delivery System (EPDS) has repetitively identified as one of main barriers to deter advancements of Korean engineering industry. Therefore, this research attempted to investigate global standards of EPDS such as International Federation of Consulting Engineers (FIDIC), American Federal Acquisition Regulations (FAR), Brooks Act, and so on. The procedures of international EPDSs along with a few case studies were comprehensively analyzed and compared with Korean EPDS in order to propose recommendations of improving Korean EPDS. Some major differences between international and Korean EPDS were identified and they includes emphasis on qualifications of engineers and/or firms rather than their proposed cost, extensive use of long and short-list, common use of negotiation process, etc. Research findings are envisioned to guide the Korean public engineering sector to innovate Korean EPDS.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.32-38
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• 2024

In the case of apartment building, it is difficult to conduct non-destructive testing due to the actual presence of people and the dust and noise generated during the core test, so inspections are performed each time in the common area and underground parking lot, and the tests are conducted on the finishing material rather than on the concrete surface due to low-cost orders. As the process progresses, poor inspection is inevitable. In addition, the proposed formulas for strength estimation have large fluctuations depending on the differences in test conditions and environments, and even if they show the same measured value, the deviation between each proposed formula is large, making it difficult to accurately estimate strength, making it difficult to use. Accordingly, we would like to select finishing materials mainly used in apartment complexes and compare and evaluate the compressive strength of concrete according to the type of finishing material by using non-destructive testing methods directly on the finishing materials without removing the finishing materials. The reliability evaluation results of the estimated compressive strength of concrete using the ultrasonic velocity method according to the type of finishing material are as follows. The error rate between the estimated compressive strength and compressive strength derived through the ultrasonic velocity method shows a wide range of variation, ranging from 21.83% to 58.89%. The effect of the presence or absence of finishing materials on the estimated compressive strength was found to be insignificant. Accordingly, it is necessary to select more types of finishing materials and study ultrasonic velocity methods according to the presence or absence of finishing materials, and to study estimation techniques that can increase reliability.

• Journal of Society of Preventive Korean Medicine
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• v.19 no.1
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• pp.95-107
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• 2015

Objective : To use and its affecting factors of patients' outpatient treatment that have single and multiple chronic illnesses Method : We used the 2011 study by the Ministry of Health and Welfare, "Report on Usage and Consumption of Korean Medicine." This report was conducted on outpatients and inpatients that visited Korean traditional medicine, from August 25th, 2011, to September 30th, 2011. Our research was based on 1729 patients with chronic diseases aged 30 and over who received outpatient treatment during the last three months. Results : There were 1365 patients with non-complex chronic diseases, while there were 364 patients with complex chronis diseases. Patients had 1 - 8 chronic diseases, and the average number (standard deviation) was 1.26 (0.59). There were statistically significant differences by sex(P<0.0001), age(p=0.0045), marriage (p=0.0060), education level(p<0.0001), income level(P=0.0063), and types of health insurance(p=0.0023). The diseases most common among patients with non-complex chronic diseases were: low back pain, arthritis, gastrointestinal disorder, frozen shoulder, side effects from motor accidents, high blood pressure, fracture, stroke, diabetes, cancer, atopic dermatitis, and asthma. The diseases most common among patients with non-complex chronic diseases were: arthritis+low back pain, low back pain+gastrointestinal disorder, low back pain+side effects from motor accidents, low back pain+frozen shoulder, arthritis+gastrointestinal disease, gastrointestinal disease+frozen shoulder, arthritis+low back pain+gastrointestinal disease, high blood pressure+arthritis, arthritis+low back pain+frozen shoulder, arthritis+fracture, and arthritis+side effects from motor accidents. There were statistically significant differences among the usage of medical clinics by: frequently used clinic (p<0.0001), number of treatment (p<0.0001), the cost of outpatient treatment (p=0.0073), the satisfaction rate (p=0.0171), whether the clinic is the preferred clinic (p=0.0040). In model 1, men than women, people who had local benefits instead of type 1 medical aid, and patients with complex chronic diseases were more likely to use Korean medical clinics. In model 2, men than women, people who had local benefits than people with types 1 and 2 medical aids, people who went to pharmacies and Korean medicine pharmacies than people who went to hospitals, people who went to get treatment 1-10 times than people who visited 11-20 times and more than 41 times, and people who spent less than ten thousand Korean won than people who spent 1 to 2 million Korean won, and people without complex chronic diseases were more likely to use Korean medical treatment. Conclusion : There were differences in sociodemographic characteristics and the usage of medical clinics between patients with non-complex chronic diseases and patients with complex chronic diseases. Among patients with complex chronic diseases, women, patients with types 1 and 2 medical aid, patients who used Korean medical clinics, patients who were treated 11-20 times and more than 41 times, and patients who spent 1 million to 2 million Korean won on outpatient treatment used less treatment than patients with non-complex chronic diseases. However, patients with complex chronic diseases used pharmacies and Korean medicine pharmacies more.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.681-686
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• 2010

Background: A chest computed-tomography has become more prevalent so that it is more common to detect small sized pulmonary nodules that have not been found in previous simple chest x-ray. If those detected nodules are undersized or located in pulmonary parenchyma, it is difficult to accomplish a biopsy since it is vulnerable to explore them either grossly or digitally. Thus, in our hospital, a thoracoscopic pulmonary wedge resection was performed after locating a lesion by means of hook wire with CT-guided. Material and Method: 31 patients (17 males and 14 female patients) from December in 2006 to June in 2010 became our subjects; their 34 pulmonary nodules were subjected to the thoracoscopic pulmonary wedge resection after locating a lesion by means of hook wire with CT-guided. Also we analyzed a possibility of hook wire dislocation, a frequency of conversion to open thoracotomy, time consumed to operation after location of a lesion, operation time, post operation complication, and histological diagnosis of the lesion. Result: 12 of 34 cases were ground glass lesion, whereas 22 cases of them were solitary pulmonary lesion. The median value of the lesion was 8mm in size (range: 3 to 23 mm), while the median value was 12.5 mm in depth (range: 1 to 34 mm). The median value of time consumed from location of the lesion to anesthetic induction was 86.5 minutes (41~473 minutes); furthermore the mean value of operation time was 103 minutes (25~345 minutes). Intrathoracic wire dislocation was found in one case, but a target lesion was successfully excised. Open thoracotomy was performed in four cases due to pleural adhesion. However, there was no case of conversion to open thoracotomy due to failure to detect a target lesion. In histological diagnosis, metastatic cancer were found in 15 cases, which were the most common, primary lung cancer were in 9 cases, non-specific inflammation were in 3 cases, tuberculosis inflammation were in 2 cases, lymph nodes were in 2 cases, active tuberculosis were in 1 case, atypical adenomatous hyperplasia was in 1 case and normal lung parenchymal finding was in 1 case, respectively. Conclusion: In our hospital, in order to accomplish a precise histological diagnosis of ground-glass lesion and pulmonary nodules in lung parenchyma, location of pulmonary nodules were exactly located with hook wire under chest computed-tomography, which was followed by lung biopsy. We concluded that this was an accurate, minimally invasive and valuable method to minimize the complications and increase of cost of medical service provided.

• Journal of Chest Surgery
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• v.42 no.1
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• pp.14-21
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• 2009

Background: Postoperative atrial fibrillation (AF) is a common complication after coronary artery bypass graft (CABG) surgery. Although postoperative AF is regarded as benign, transient and self-limited, it has been associated with increased morbidity, thromboembolic events and an increased duration and cost of hospitalization. Material and Method: From January 1994 to December 2007, 190 patients that had isolated CABG surgery were divided into two groups. Group 1 (n=139) involved those who had postoperative atrial fibrillation, and group 2 (n=51) did not have any such events. We reviewed the medical records retrospectively including the incidence of postoperative AF, patient characteristics, surgery related factors and the outcome of the patients with postoperative AF. Result: The frequency of postoperative AF was 26.8%, the conversion rate to regular sinus rhythm before discharge was 82.4%; 82.4% of the AF developed within the first three postoperative days. Although the postoperative AF group was significantly older and had a prolonged postoperative Intensive care unit (ICU) stay, there was no difference in the aortic crossclamp time or duration of hospitalization. No spontaneous defibrillation at declamping, and longer duration of cardiopulmonary bypass were significantly related to the development of postoperative AF. However, postoperative treatment with a beta blocker was associated with a decreased incidence of postoperative AF. The multivariate analysis showed that age and ICU stay were significantly associated with the development of POAF. Spontaneous defibrillation and postoperative beta blocker treatment were significantly associated with a decreased frequency of POAF. Conclusion: AF after CABG surgery is a common complication associated with increased morbidity and a longer ICU stay. Therefore, various strategies aimed at reducing AF, and its complications, such as postoperative treatment with a beta blocker should be considered.