• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1032-1039
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• 2012

The present paper deals with precise relative positioning of formation satellites with long baseline in low Earth orbit making use of L1/L2 dual frequency GPS carrier phase measurements. Kinematic approach means to describe the motion of objects without taking its mass/dynamics model into consideration. The advantage of the kinematic approach is that information about dynamics of the system is not applied, which gives more flexibility and could improve the scientific interest of the observations made by the mission. The ionosphere terms, which are not canceled by double differenced measurement equation in the case of the long baseline, are explicitly estimated as unknown parameters by extended Kalman filter. The estimated float ambiguities by EKF are solved by existing efficient integer vector search strategy under integer least square condition. For the integer vector search, we employ well known MLAMBDA. Finally, The feasibility and accuracy of processing scheme are demonstrated using the GPS measurements for two satellites in low Earth orbit separated by baselines of 100 km.

• Journal of Korea Technology Innovation Society
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• v.15 no.1
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• pp.203-223
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• 2012

This study aimed to identify the factors of failure in cases where there was feasibility but was not successful in commercializing technology. For the study, 92 feasibility reports for new technologies were collected, and among these 4 studies that showed definite failure in commercialization of technology were analyzed in depth. Further analysis was based the factors pointed out by previous frameworks such as 1) discussion on success or failure in commercialization of technology, 2) that of venture company, and 3) valuation of technology studies. Previous studies pointed out success and failure factors as lack of funding, uncontrollable accidents, managing ability, inability for mass production and so forth, which had little difference to the pre-feasible evaluation of four cases. However, real reason was the lack of understanding technologies such as composition of technologies, production technologies required by stages, and lack of understanding of floor technologies. The misunderstandings were occurred regardless of CEO's experience and expertise. We did not touch the evaluation model of pre-feasibility studies, although we dealt with the failure of the pre-studies. The reason we do not generalize the results of this study is the fact that we dealt with only small cases.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.22-30
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• 2004

It is an attempt to suggest the standard valuation method of the environmental illumination for the bridges across the Han-river from an aesthetic point of view, deviating from the technical and traditional viewpoint. In Korea the current evaluation criterion to verify the value of bridge design has a partiality for the technical and structural safety rather than the sentient beauty on the whole. However, the recently cultural reform of Korean mass society with the elevation of the standard of living forces the engineering designers for bridges to focus not only on competing physical structures but also on enhancing the formative beauty including the illumination effects for night view. Additionally, the new policy, which transforms the environments around the Han-river into the major tourist attractions has been executing strongly by the city authorities to revitalize the symbolic, historic, and cultural identity of the capital city with the introduction of the high-quality environmental illumination for the bridges. As a result, It becomes necessary to establish the manual and standardization of the environmental illumination planning for the city in terms of the formative beauty, and this study is to suggest the valuation model method of the environmental illumination for the bridges as the initial step of the standardization. In the study, the valuation items of the standard questionnaire are selected by the documentary records and the consultation of various experts in architecture, design, fine art, urban planning and even administration to verify the essential elements of the aesthetic beauty with the local amenity and the environmental harmony for the chosen bridges across the Han-river.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.459-468
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• 2000

Objectives : To investigate the association between BMI and Mortality. Methods : This study was based on the analysis and assembly of the 'Kangwha Cohort Study', previously conducted by the Department of Preventive Medicine, Yonsei University. A total of 2,696 males and 3,595 females were followed for almost ten years and ten months from March 1985 to January 1996, a total of whom 2,420 died during this period. The Cox's proportional hazards regression model was used to analyze this data. Results : We found a U-shaped relationship between BMI and mortality among the aged men in the Kangwha cohort. The hazard ratio of dying was adjusted for age, marital status, occupation, self cognitive health level, chronic disease, smoking, and alcohol frequency, then sorted by body mass index into the following groups; less than 10.5, 18.5 to less than 21.0, 21.0 to less than 23.5, 23.5 to less than 26.0 and greater than or equal to 26. The corresponding ratios for men were 1.81(1.50-2.19, 95%CI), 1.31(1.14-1.51, 95%CI), 1.0(referent), 1.05(0.87-1.26, 95%CI) and 1.39(1.09-1.76, 95%CI), respectively. And for women, 1.46(1.19-1.78), 1.12(0.95-1.31, 95%CI), 1.0(referent), 1.00(0.84-1.20, 95%CI) and 1.09(0.89-1.34, 95%CI), respectively. Conclusions : The risk of death among aged men in Kangwha increased in the under and overweight groups. The relationship between BMl and mortality has been well studied in Western populations, but little is known about the association between BMI and mortality in our country. So, on the basis of this study, it is apparent that more studies of the relationship between BMI and mortality will be needed for future work.

• Molecules and Cells
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• v.38 no.8
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• pp.685-696
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• 2015

Rice is a model plant widely used for basic and applied research programs. Plant cell wall proteins play key roles in a broad range of biological processes. However, presently, knowledge on the rice cell wall proteome is rudimentary in nature. In the present study, the tightly-bound cell wall proteome of rice callus cultured cells using sequential extraction protocols was developed using mass spectrometry and bioinformatics methods, leading to the identification of 1568 candidate proteins. Based on bioinformatics analyses, 389 classical rice cell wall proteins, possessing a signal peptide, and 334 putative non-classical cell wall proteins, lacking a signal peptide, were identified. By combining previously established rice cell wall protein databases with current data for the classical rice cell wall proteins, a comprehensive rice cell wall proteome, comprised of 496 proteins, was constructed. A comparative analysis of the rice and Arabidopsis cell wall proteomes revealed a high level of homology, suggesting a predominant conservation between monocot and eudicot cell wall proteins. This study importantly increased information on cell wall proteins, which serves for future functional analyses of these identified rice cell wall proteins.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.742-748
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• 1998

Experiments have been conducted to investigate synergistic effects and mechanisms of the Alaskan subbituminous coal/polypropylene (PP). Coliquefaction of coal/PP gave the synergistic effect in yields by 17% compared to independent liquefactions of coal or PP at $430^{\circ}C$. To analyse coliquefaction mechanisms, the second and zeroth order kinetic models were developed for coal and PP conversions respectively. When the models were simulated to fit coliquefaction results, those represented results successfully with the correlation coefficient of 0.99. The amount of tetralin needed to liquefy unit mass of coa 1(${\beta}$) was also calculated using the developed model. According to the calculated results, $\beta$ increased from 0.4 to 1.0 as the coliquefaction temperature increased from $410^{\circ}C$ to $470^{\circ}C$. This indicated that tetralin lowered the molecular weight of oil produced, and this phenomenon was recognized by the GPC analyses. Furthermore, it was found that tetralin prohibited the liquefaction of PP when coal was not added. On the other hand, tetralin was believed to act as a hydrogen-donor solvent to coal rather than prohibit PP liquefaction during coliquefaction. Therefore, the liquefaction rate of PP increases and synergistic effects in oil yields are mainly due to the increase in PP liquefaction during coal/PP coliquefaction.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.221-227
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• 2001

Objective : The therapeutic impact of tumor resection in glioblastomas is poorly defined and still questionable. Therefore, we conducted the current study to verify the role of tumor resection in the treatment of these highly malignant tumors. Methods : A retrospective study was performed(1990-1999) to compare the treatment results of surgical resection plus radiotherapy(130 patients) with those of stereotactic biopsy plus radiotherapy(19 patients) in glioblastomas. Only adult patients with supratentorial, de novo glioblastoma located in one lobe were included. Survival time/rate was analysed with Kaplan-Meier method, and prognostic variables were obtained from the univariate log-rank test and the multivariate Cox's proportional hazards model. Results : The resection group and the biopsy group did not differ in terms of age, gender, duration of symptoms, presenting symptoms, tumor location, tumor side, tumor size, and the frequency of midline shift. Patients in the biopsy group more often were found to have worse preoperative Karnofsky performance status(KPS)(p=0.001). On univariate analysis, age, KPS, and tumor side were associated with survival(p=0.0053, 0.0001, and 0.0331 respectively). Median survival time and 1-year survival rate were also statistically improved by tumor resection ; resection group - 13 months and 61.2%, and biopsy group - 8 months and 19.7%, respectively(p=0.0001). In patients with midline shift of the tumor, resection was highly effective comparing to biopsy(p=0.0001), but in patients without midline shift, external beam radiation alone was as effective as tumor resection(p=0.0605). Other prognostic variables did not affect survival. On multivariate analysis after variable selection, survival was independently associated with KPS(p=0.001), but not the surgical resection(p=0.2837). Even in biopsy group with midline shift of the tumor, survival rate was not different from that seen after tumor resection(p=0.3505). Conclusions : Radiotherapy alone was as effective as tumor resection plus radiotherapy in patients without midline shift of the tumor. Although there was not statistically significant, tumor resection looked like effective in patients with midline shift. For supratentorial, lobar glioblastoma patients without mass effect of the tumor, biopsy with radiotherapy is one of rational treatment strategies. We consider that tumor resection should be performed in patients with pretreatment midline shift.

• Experimental and Molecular Medicine
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• v.50 no.12
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• pp.12.1-12.14
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• 2018

Osteoporosis develops with high prevalence in both postmenopausal women and hypogonadal men. Osteoporosis results in significant morbidity, but no cure has been established. Mesenchymal stem cells (MSCs) critically contribute to bone homeostasis and possess potent immunomodulatory/anti-inflammatory capability. Here, we investigated the therapeutic efficacy of using an infusion of MSCs to treat sex hormone-deficient bone loss and its underlying mechanisms. In particular, we compared the impacts of MSC cytotherapy in the two genders with the aim of examining potential gender differences. Using the gonadectomy (GNX) model, we confirmed that the osteoporotic phenotypes were substantially consistent between female and male mice. Importantly, systemic MSC transplantation (MSCT) not only rescued trabecular bone loss in GNX mice but also restored cortical bone mass and bone quality. Unexpectedly, no differences were detected between the genders. Furthermore, MSCT demonstrated an equal efficiency in rectifying the bone remodeling balance in both genders of GNX animals, as proven by the comparable recovery of bone formation and parallel normalization of bone resorption. Mechanistically, using green fluorescent protein (GFP)-based cell-tracing, we demonstrated rapid engraftment but poor inhabitation of donor MSCs in the GNX recipient bone marrow of each gender. Alternatively, MSCT uniformly reduced the $CD3^+T$-cell population and suppressed the serum levels of inflammatory cytokines in reversing female and male GNX osteoporosis, which was attributed to the ability of the MSC to induce T-cell apoptosis. Immunosuppression in the microenvironment eventually led to functional recovery of endogenous MSCs, which resulted in restored osteogenesis and normalized behavior to modulate osteoclastogenesis. Collectively, these data revealed recipient sexually monomorphic responses to MSC therapy in gonadal steroid deficiency-induced osteoporosis via immunosuppression/anti-inflammation and resident stem cell recovery.

• Journal of Korean Medical Science
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• v.33 no.51
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• pp.325.1-325.10
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• 2018

Background: To evaluate survival outcomes and prognostic factors for overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC) who received sunitinib (SU) and pazopanib (PZ) as first-line therapy in real-world Korean clinical practice. Methods: Data of 554 patients with mRCC who received SU or PZ at eight institutions between 2012 and 2016 were retrospectively reviewed. Based on the targeted therapy, the patients were divided into SU (n = 293) or PZ (n = 261) groups, and the clinicopathological variables and survival rates of the two groups were compared. A multivariable Cox proportional hazard model was used to determine the prognostic factors for OS. Results: The median follow-up was 16.4 months (interquartile range, 8.3-31.3). Patients in the PZ group were older, and no significant difference was observed in the performance status (PS) between the two groups. In the SU group, the dose reduction rate was higher and the incidence of grade 3 toxicity was more frequent. The objective response rates were comparable between the two groups (SU, 32.1% vs. PZ, 36.4%). OS did not differ significantly between the two groups (SU, 36.5 months vs. PZ, 40.2 months; log-rank, P = 0.955). Body mass index, Eastern Cooperative Oncology Group PS > 2, synchronous metastasis, poor Heng risk criteria, and liver and bone metastases were associated with a shorter OS. Conclusion: Our real-world data of Korean patients with mRCC suggested that SU and PZ had similar efficacies as first-line therapy for mRCC. However, PZ was better tolerated than SU in Korean patients.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.232-232
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• 2019

The persistence of drought periods and water scarcity is a growing public concern, as climate change projections indicate a more critical scenario in the future. The sustainability of water resources for the increasing population, and to ensuring crop production will unarguably be a daunting task for the water resources managers, with a projected 9.8 billion people by 2050 as well as the need to increase food production by 70 to 100%. Consequently, there is a need for significant irrigation water use for more crop production in the face of stiff competition among water users. However, the available natural resources are already over-constrained, and the allocation of more resources for food production is not feasible. Currently, about two-thirds of global water withdrawer is used by the agricultural sector while 48% of water resources in Korea is used for agricultural production. Despite the apparent ecological deficit and unfavorable conditions of resources utilization, a staggering amount of food waste occurs in the country. Moreover, wastage of food translates to waste of all the resources involved in the food production including water resources. Food waste can also be considered a serious potential for economic and environmental problems. Hence, exploring an alternative approach to efficient resources utilization in a more sustainable way can ensure considerable resources conservation. We hypothesized that reducing food waste will decline the demand for food production and consequently reduce the pressure on water resources. We investigated the food wastage across the food supply chain using the top-down datasets based on the FAO mass balance model. Furthermore, the water footprint of the estimated food wastage was assessed using the representative of selected food crops. The study revealed that the average annual food wastage across the food supply chain is 9.05 million tonnes, signifying 0.51 kg/capita/day and 48% of domestic food production. Similarly, an average of 6.29 Gm3 per annum of water resources was lost to food wastage, which translates to 40% of the total allotted water resources for agriculture in the country. These considerable resources could have been conserved or efficiently used for other purposes. This study demonstrated that zero food waste generation would significantly reduce the impact on freshwater resources and ensure its conservation. There is a need for further investigation on the food waste study using the bottom-up approach, specifically at the consumer food waste, since the top-down approach is based on estimations and many assumptions were made.