• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1223-1231
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• 2010

The design is presented for a SATCOM antenna capable of simultaneous multi-band (X/Ku/Ka-Band) communications without replacement of feed horns or change of other parts in the application as a ground satellite terminal for large data transfer. The antenna is the offset configuration and consists of a dual-band(X/Ka-band) feed horn, a single-band(Ku-band) feed horn, a frequency selective surface(FSS) sub-reflector and a parabolic main-reflector. The antenna has a main reflector defining a prime focus and a frequency selective surface sub-reflector defining an image focus. A dual-band feed and a single-band feed are provided at each of the prime focus and image focus. The antenna is designed using 3D EM simulator and the gains measured in X/Ku/Ka-band of the complete antenna assembly is more than 31.6dBi, 36.8dBi, 40.8dBi, and the cross polarization is 21.7dB, 26.6dB, 25.2dB, respectively.

• Biomedical Science Letters
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• v.8 no.4
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• pp.217-221
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• 2002

Age-related osteopenia and osteoporosis are common in postmenopausal women due to decrease in bone mass and ovarian function. A therapy for osteoporosis would depend on only drugs to inhibit bone loss, hormonal replacement therapy, exercise and dietary supplementation and it is very hard to fad an ideal therapy for osteoporosis as yet. Chlorella which is rich in minerals such as calcium magnesium fatty acids, vitamins and sterol, could be applicable for prevention and co-treatment of osteoporosis, but it has yet to be studied. The purpose of this study was to assess the relationship between the effect of dietary chlorella on bone mineral density (BMD) and nutritional improvement. BMD was measured in the femural neck and lumber spine portion. Nutritional and bone turnover markers from blood samples were assessed serum lkaline phosphatase, hemoglobin, number of erythrocytes and total protein. Studies for the femur neck measurement showed that normal BMD increased 2.1% for the group fed chlorella supplemented diet for four month and increased 6.6% fur group treated for one year when compared to the control group, and for the lumber spine measurements the few month group showed an increase of 9.1% over the control group, the one year group showed an increase of 64.2% over the control group. Hemoglobin content, number of erythrocytes and total protein showed similar increased patterns with BMD measurement, meanwhile, serum alkaline phosphatase increased 3% for the four month group and decrease 16% for the one year group compare to the control group. In conclusion, the postmenopausal women fed chlorella supplemented diet results in an increase in BMD. This is a marked increment in lumber spine, enhancement of nutritional state and stable bone turnover. This data showed a positive relationship between BMD and nutritional change with chlorella treatment, and suggested that chlorella dietary may lead to improving and preventing rapid loss of BMD in postmenopausal women.

• Journal of KIISE:Databases
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• v.34 no.2
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• pp.109-118
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• 2007

Recently, flash memory is used to store data in mobile computing devices such as PDAs, SmartCards, mobile phones and MP3 players. These devices need index structures like the B-tree to efficiently support some operations like insertion, deletion and search. The BFTL(B-tree Flash Translation Layer) technique was first introduced which is for implementing the B-tree on flash memory. Flash memory has characteristics that a write operation is more costly than a read operation and an overwrite operation is impossible. Therefore, the BFTL method focuses on minimizing the number of write operations resulting from building the B-tree. However, we indicate in this paper that there are many rooms of improving the performance of the I/O cost in building the B-tree using this method and it is not practical since it increases highly the usage of the SRAM memory storage. In this paper, we propose a BOF(the B-tree On Flash memory) approach for implementing the B-tree on flash memory efficiently. The core of this approach is to store index units belonging to the same B-tree node to the same sector on flash memory in case of the replacement of the buffer used to build the B-tree. In this paper, we show that our BOF technique outperforms the BFTL or other techniques.

• The KIPS Transactions:PartA
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• v.15A no.1
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• pp.53-60
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• 2008

Streaming media has contributed to a significant amount of today's Internet Traffic. Like traditional web objects, rich media objects can benefit from proxy caching, but caching streaming media is more of challenging than caching simple web objects, because the streaming media have features such as huge size and high bandwidth. And to support various bandwidth requirements for the heterogeneous ubiquitous devices, a transcoding proxy is usually necessary to provide not only adapting multimedia streams to the client by transcoding, but also caching them for later use. The traditional proxy considers only a single version of the objects, whether they are to be cached or not. However the transcoding proxy has to evaluate the aggregate effect from caching multiple versions of the same object to determine an optimal set of cache objects. And recent researches about multimedia caching frequently store initial parts of videos on the proxy to reduce playback latency and archive better performance. Also lots of researches manage the contents with segments for efficient storage management. In this paper, we define the 9-events of transcoding proxy using 4-atomic events. According to these events, the transcoding proxy can define the next actions. Then, we also propose the segment-based caching policy for the transcoding proxy system. The performance results show that the proposing policy have a low delayed start time, high byte-hit ratio and less transcoding data.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.15-20
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• 2002

The Hydroxyethyl methacrylate(HEMA) was developped in 1960's and later the use of contact lenses increased. At present more and more people use RGP contact lenses. Due to the wide range of optical corrections available and due to their high oxygen transmission Japanese and Korean people like them. Nevertheless one of nine CL users(beginners) stopped wearing the CL within the first year. We conducted a survey to evaluate the level of patient compliance in lens care and maintenance and to assess practitioner knowledge of contact lens information. Generally 6% of contact lens wearers drop out per year. The aim of this research was to find out what opticians can do to reduce the drop-out rate by getting information on handling, on general data of the patient and on optical prescription. Lens wearer were asked to complete a 10 question survey that focused on lens care-wear modality, lens replacement, storage, symptoms and case disinfection. There were total 180 participants in the study. Most of contact lens wearers have an inadequate understanding of contact lens care system. Therefore, it is important that contact lens specialists place more emphasis on practitioner education about general contact lens fields and reinforce patient education during the dispensing visit.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.727-736
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• 2010

This paper describes results of an preliminary study to produce strain hardening cement-based composites (SHCCs)with consideration of sustainability for infrastructure applications. The aims of this study are to evaluate the influence of recycled materials on the mechanical characteristics of SHCCs, such as compressive, four-point bending, and direct tensile behaviors, and to give basic data for constitutive model for analyzing and designing infra structures with SHCCs. In this study, silica sand, cement, and PVA fibers, were partially replaced with recycled sand, fly-ash, and FET fibers in the mixture of SHCCs, respectively. Test results indicated that fly-ash could improve both bending and direct tensile performance of SHCCs due to increasing chemical bond strength at the interface between PVA fibers and cement matrices. However, SHCCs replaced with PET fibers showed much lower performance in bending and direct tensile tests due to originally low mechanical properties of own fibers, although compressive behavior is similar to PVA2.0 specimen. Also, it was noted that the recycled sand would increase elastic modulus of SHCCs due to larger grain size compared to silica sand. Based on pre-set target value to maintain the performance of SHCCs, it was concluded that the replacement ratio below 20% of fly-ash or below 50% of recycled sands would be desirable for creating sustainable SHCCs.

• Journal of the Korean Society of Radiology
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• v.11 no.3
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• pp.153-159
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• 2017

Chronic kidney disease can be treated if it is detected early, but as the disease progresses, it becomes impossible to recover. Finally, renal replacement therapy such as transplantation or dialysis should be used. Ultrasonography is used to diagnose kidney cancer, inflammatory disease, nodular disease, and chronic kidney disease. It is used to identify information about degree of inflammation using information such as kidney size, internal echo characteristics. Currently, the degree of disease in the clinic uses the value of glomerular filtration rate. However, even in ultrasound, changes in the degree of inflammation and disease can be observed. In this study, we used ultrasound images to quantify the changes in brightness, size, cortex, and subclinical changes of the kidney with progression of the disease, and compared them with the glomerular filtration rate used in clinical practice. In 105 cases, we performed 35 cases of normal kidney, 35 cases of early kidney disease, and 35 cases of terminal kidney. The brightness of the cortex of the image was obtained and the difference in brightness between the cortex and the proximal portion was obtained by the slope. The graph of the portion which was not smooth due to the ultrasonic characteristics was used as the function regrass. The size reduction was obtained from the original data. The results were as follows: It was proportional to the glomerular filtration rate. It is considered that the algorithm can be applied to the disease if the algorithm study continues.

• Journal of Preventive Medicine and Public Health
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• v.38 no.1
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• pp.82-92
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• 2005

Objective : To evaluate the relationships among sociodemographic characteristics, health behaviors, levels of pros and cons and stages of change in Pap testing for uterine cervical cancer. Methods : A questionnaire survey was performed on 560 randomly sampled people who were assigned to participate in a Pap testing program by the National Cancer Screening Project in 2003' between 25 September and 10 October in Gyeonggi, Korea. Data about the behaviors and intentions of Pap testing, sociodemographic characteristics, health behaviors, and levels of acknowledged benefit (pros) and barrier (cons) for Pap testing was collected. The stages of change were grouped according to behaviors and intentions of Pap testing as passive, active, and relapse. Results : Logistic analysis between the passive and active groups showed that city dwellers, 'high' and 'middle' groups in terms of the individual s health belief, those who had undergone a health examination within the past 2 years, and those who had undergone hormone replacement therapy had a higher odds ratios to be in the active group. As the 'benefit' scores increased and the 'Unnecessity' scores decreased, the probabilities to be in the active group increased. According to the logistic analysis results between the active and relapse groups, those who were 60 years or older, members of the National Heath Insurance, and those who had not undergone a health examination within the past 2 years had a higher odds ratio to be in the relapse group. The 'Benefit' scores were not significant in this relationship. The probabilities of being in the relapse group increased as the Unnecessity and 'Shamefulness' scores increased. Conclusions : In conclusion, health planners should inform women in the passive group of the benefits and necessity of Pap testing. It would be better to reduce the barriers to the active group of undergoing Pap smear. This study might be a useful guide for future planning of Pap testing program.

• Journal of Chest Surgery
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• v.45 no.4
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• pp.236-241
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• 2012

Background: Prolonged usage of extracorporeal membrane oxygenation (ECMO) may induce multi-organ failure. This study is aimed to evaluate prognostic factors in the patients with ECMO. Also, the prognosis of ECMO with Kidney Injury Network Scoring system is studied. Materials and Methods: From May 2005 to July 2011, 172 cases of ECMO were performed. The cases of perioperative use of ECMO were excluded. Renal failure patient and younger than 15 years old one were also excluded. As a result, 26 cases were enrolled in this study. Male patients were 15 (57.7%), and mean age was $56.57{\pm}17.03$ years old. Demographic data, ECMO parameters, weaning from ECMO, and application of continuous renal replacement therapy are collected and Acute Kidney Injury Network (AKIN) scores were evaluated just before ECMO and day 1, day 2 during application of ECMO. Results: Venoarterial ECMO was applied in 22 cases (84.6%). The reasons for applications of ECMO were cardiac origin in 21 (80.8%), acute respiratory distress syndrome in 4, and septic shock in 1 case. Successful weaning from ECMO was achieved in 15 cases (57.7%), and survival discharge rate was 9 cases (34.6%). Mean duration of application of ECMO was $111.39{\pm}54.06$ hours. In univariate analysis, myocarditis was independent risk factors on weaning failure. Using the receiver operating characteristic curve, level of hemoglobin on 24 hours after ECMO, and base excess on 48 hours after ECMO were showed more than 0.7. AKIN score was not matched the prognosis of the patients with ECMO. Conclusion: In our study, the prognosis of the patients with myocarditis was poor. Hemoglobin level at first 24 hours, and degree of acidosis at 48 hours were useful methods in relating with prognosis of ECMO. AKIN scoring system was not related with the prognosis of the patients. Further study for prognosis and organ injury during application ECMO may be needed.

• Korean Journal of Community Nutrition
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• v.21 no.4
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• pp.378-385
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• 2016

Objectives: This study was conducted to investigate the association between sarcopenia and sarcopenic obesity and cardiovascular disease risk in Korean postmenopausal women. Methods: We analyzed data of 2,019 postmenopausal women aged 50-64 years who participated in the Korea National Health and Nutrition Examination Survey in 2008-2011 and were free of cardiovascular disease history. Blood pressure, height, and weight were measured. We analyzed the serum concentrations of glucose, total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglyceride levels. Waist circumference was used to measure obesity. Appendicular skeletal muscle mass was measured by dual-energy X-ray absorptiometry. Sarcopenia was defined as the appendicular skeletal muscle mass/body weight<1 standard deviation below the gender-specific means for healthy young adults. The estimated 10-year risk of cardiovascular disease risk was calculated by Pooled Cohort Equation. Subjects were classified as non-sarcopenia, sarcopenia, or sarcopenic obesity based on status of waist circumference and appendicular skeletal muscle mass. Results: The prevalence of sarcopenia and sarcopenic obesity was 16.3% (n=317) and 18.3% (n=369), respectively. The 10-year risk of cardiovascular disease risk in the sarcopenic obesity group was higher ($3.82{\pm}0.22%$) than the normal group ($2.73{\pm}0.09%$) and sarcopenia group ($3.17{\pm}0.22%$) (p < 0.000). The odd ratios (ORs) for the ${\geq}7.5%$ 10-year risk of cardiovascular disease risk were significantly higher in the sarcopenic obesity group (OR 3.609, 95% CI: 2.030-6.417) compared to the sarcopenia group (OR 2.799, 95% CI: 1.463-5.352) (p for trend < 0.000) after adjusting for independent variables (i.e., exercise, period of menopausal, alcohol use disorders identification test (AUDIT) score, income, education level, calorie intake, %fat intake and hormonal replacement therapy). Conclusions: Sarcopenia and sarcopenic obesity appear to be associated with higher risk factors predicting the 10-year risks of cardiovascular disease risk in postmenopausal women. These findings imply that maintaining normal weight and muscle mass may be important for cardiovascular disease risk prevention in postmenopausal women.