• East Asian Economic Review
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• v.28 no.2
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• pp.245-273
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• 2024

This paper sets up a small open new Keynesian economy model with constrained households and incomplete markets to address the driving forces of business cycles in Korea. It shows that there exists a substantial fraction of constrained households who cannot have access to financial market. Furthermore, the estimated model reveals that a TANK model is better than a RANK model in explaining business cycles in Korea. The effect of domestic productivity shock on Korean economy has dominated in the variations of output, while the contribution of the foreign productivity shock to the variations of output and inflation has increased after the Asian financial crisis. The monetary policy shock has dominated the variation of inflation at short and medium horizons.

• The Journal of Korean Obstetrics and Gynecology
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• v.26 no.3
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• pp.73-84
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• 2013

Objectives: This study aims to identify associated factors in female infertility treatment using herbal medicine, acupuncture and moxibustion. Methods: Acupuncture and moxibustion treatments were performed with intake of herbal medicines (Jokyungjongoktanggagam-bang, Sutaehwangagam-bang) for six menstrual cycles in 32 subfertile women. The variables selected for initial analysis were age, duration and type of infertility, frequency of previous In Vitro Fertilization (IVF) and live births, weekly frequency of sexual intercourse, number of treatment cycles, endometrial thickness on MCD15 and hormonal parameter (anti-mullerian hormone, follicle-stimulating hormone, luteinizing hormone, estrone). Results: Six patients became pregnant (18.75%) and seven patients withdrew. Factors influenced pregnancy were age (${\leq}35$ years), a shorter duration of infertility (<6 years), frequency of IVF (${\leq}3$), anti-mullerian hormone level (>1 ng/ml), and number of treatment cycles(${\leq}3$ cycles). Conclusions: Korean medicine is a useful and optimized treatment option for women with younger age, fewer previous IVF cycles, shorter infertile duration and normal anti-mullerian hormone level at first 3 cycles of treatment.

• Korean Journal of Materials Research
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• v.24 no.11
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• pp.585-590
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• 2014

Microstructural evolution in the thickness direction of an oxygen free copper processed by accumulative rollbonding (ARB) is investigated by electron back scatter diffraction (EBSD) measurement. For the ARB, two copper alloy sheets 1 mm thick, 30 mm wide and 300 mm long are first degreased and wire-brushed for sound bonding. The sheets are then stacked and roll-bonded by about 50% reduction rolling without lubrication at an ambient temperature. The bonded sheet is then cut to the two pieces of the same dimensions and the same procedure was repeated on the sheets up to eight cycles. The specimen after 1 cycle showed inhomogeneous microstructure in the thickness direction so that the grains near the surface were finer than those near the center. This inhomogeneity decreased with an increasing number of ARB cycles, and the grain sizes of the specimens after 3 cycles were almost identical. In addition, the aspect ratio of the grains decreased with an increasing number of ARB cycles due to the subdivision of the grains by shear deformation. The fraction of grains with high angle grain boundaries also increased with continuing process of the ARB so that it was higher than that of the low angle grain boundaries in specimens after 3 cycles. A discontinuous dynamic recrystallization occurred partially in specimens after 5 cycles.

• Geomechanics and Engineering
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• v.12 no.4
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• pp.611-626
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• 2017

The research reported herein is concerned with the model testing of piles socketed in soft rock which was simulated by cement, plaster, sand, water and concrete hardening accelerator. Model tests on a single pile socketed in simulated soft rock under axial cyclic loading were conducted and the bearing capacity and accumulated deformation characteristics under different static, and cyclic loads were studied by using a device which combined oneself-designed test apparatus with a dynamic triaxial system. The accumulated deformation of the pile head, and the axial force, were measured by LVDT and strain gauges, respectively. Test results show that the static load ratio (SLR), cyclic load ratio (CLR), and the number of cycles affect the accumulated deformation, cyclic secant modulus of pile head, and ultimate bearing capacity. The accumulated deformation increases with increasing numbers of cycles, however, its rate of growth decreases and is asymptotic to zero. The cyclic secant modulus of pile head increases and then decreases with the growth in the number of cycles, and finally remains stable after 50 cycles. The ultimate bearing capacity of the pile is increased by about 30% because of the cyclic loading thereon, and the axial force is changed due to the applied cyclic shear stress. According to the test results, the development of accumulated settlement is analysed. Finally, an empirical formula for accumulated settlement, considering the effects of the number of cycles, the static load ratio, the cyclic load ratio and the uniaxial compressive strength, is proposed which can be used for feasibility studies or preliminary design of pile foundations on soft rock subjected to cyclic loading.

• Journal of Environmental Science International
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• v.21 no.2
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• pp.189-202
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• 2012

Power spectral analysis for $PM_{10}$ observed at 10 cities in the Korean Peninsula from 2004 to 2010 was carried out to examine the spatial and temporal features of $PM_{10}$ evolution cycle. The power spectrum analysis proposed 9 typical cycles (0.5 day, 1day, 5.4day, 8~10day, 19~21day, 26day, 56day, 180day and 365day) for $PM_{10}$ evolution and the cycles are strongly associated with dilution and transportation due to the meterological influence. The spectrum intensity of 5.4day and 26day $PM_{10}$ evolution cycles mainly depend on the advection cycles of synoptic pressures system and long-term variation of climatological forcing, respectively. The intensity of $PM_{10}$ evolution with longer temporal cycles than one day tends to be stronger in La ni$\tilde{n}$a period in comparison with that in El ni$\tilde{n}$o period. Mean of typical intensity of $PM_{10}$ evolution in La ni$\tilde{n}$a period estimated to be 30% larger than El ni$\tilde{n}$o period. Thus the global scale meteorological phenomena such as El ni$\tilde{n}$o and La ni$\tilde{n}$a also can influence the variation of wind system in the Korean Peninsula and $PM_{10}$ evolution. but global scale forcing tends to influence different manner for $PM_{10}$ evolution in accordance with its temporal cycles.

• Clinical and Experimental Reproductive Medicine
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• v.39 no.3
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• pp.114-117
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• 2012

Objective: It is well known that fresh blastocyst transfer results in better pregnancy outcomes with a smaller number of transferred embryos compared with cleavage stage embryo transfer. However, in terms of frozen-thawed blastocyst transfer, only a few studies are available. We aimed to evaluate clinical outcomes of frozen-thawed embryo transfer (FET) with blastocysts. Methods: Retrospective analysis of FET cycles with blastocysts (B-FET) between Jan 2007 and June 2009 was performed. Age-matched FET cycles with cleavage stage embryos (C-FET) during the same period were collected as controls. A total of 58 B-FET cycles were compared with 172 C-FET cycles and also compared with those of post-thaw extended culture blastocysts from frozen pronuclear stage embryos (22 cycles). Results: There was no difference in the patient characteristics of each group. The embryos' survival rates after thawing were comparable (>90%) and there was no difference in the implantation rate or clinical and ongoing pregnancy rate among the three groups. Conclusion: In FET, blastocyst transfers may not present better pregnancy outcomes than cleavage stage embryo transfers. A further large-scale prospective study is needed.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.1
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• pp.47-51
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• 2017

Objective: This study was designed to report the status of assisted reproductive technology (ART) therapy in South Korea between January 1, 2012 and December 31, 2012. Methods: A localized online survey, originally developed by the International Committee Monitoring Assisted Reproductive Technologies, was first launched and provided to all available ART centers via email in 2015. Fresh embryo transfer (FET) cases were categorized as standard in vitro fertilization, intracytoplasmic sperm injection (ICSI), or half-ICSI. Thawed embryo transfer (TET) and other related procedures, including surgical sperm retrieval, were surveyed. Results: Data from 33,956 ovum pick-up procedures were provided by 75 clinics in 2012. Of the 33,088 cycles in which ovums were retrieved, a complete transfer was performed in 90.5% (29,932 cycles). In addition, 10,079 FET cycles were confirmed to have resulted in clinical pregnancy, representing a pregnancy rate of 30.5% per ovum pick-up and 33.7% per ET. The most common number of embryos transferred in FET was 2 (41.6%), followed by 3 (34.0%), and non-elective single ETs (10.0%). Of the 10,404 TET cycles in which transfer was completed, 3,760 clinical pregnancies (36.1%) were confirmed by ultrasonography. Conclusion: The overall clinical pregnancy rate for FET and TET cycles in 2012 was higher than in 2011 (33.7% vs. 33.2% and 36.1% vs. 31.1%, respectively). The most common number of embryos transferred in FET cycles was 2, unlike in 2011.

• Asian Journal of Turfgrass Science
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• v.11 no.1
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• pp.1-7
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• 1997

This study was performed to find out the mineral cycles of manganese and zinc in dynamic grassland ecosystems in a steady state condition at the northwest side on Mt. Kwanak. The experimental results may be summarized on the communities of a Zoysia japonica and a Miscanthus sincnsis as follows. As compared with some properties of the surface soils among two semi-natural grasslands, manganese and zinc was greater quantity in a Miscanthus sincnsis than in a Zoysia japonica on Mt. Kwana For the case of steady procluction and release, the ratio of annual mineral production to the amount accumulated on the top of mineral soil in a steady state provides the estimates of release constant k. The release constants of Mn and Zn of the litter were 0.19 and 0. 14 in the Zoysia japon- ica grassland, and were 0.44 and 0.41 in a Miscanthus sincnsis grassland, respectively. The halftimes of Mn and Zn required for the release or accumulation of the litter on the grassland were 3. 65 and 4.95 years in the Zoysia japonica, and were 1.57 and 1.69 years in the Miscanthus sincnsis, respectively. The amounts of annual cycles for Mn and Zn in the grassland ecosystem under the steady-state conditions were 58.60 and 21.46 mg /$m^2$ in a Zoysia japonica, and were 372.12 and 321.49 ing /m$^2$ in a Miscanthus sincnsis grassland. Key words: Zoysia japonica. Miscanthus sincnsis, Mt. Kwanak, Manganese, Zinc, Mineral cycles.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.890-894
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• 2015

Recently, research on high-efficiency refrigeration cycles that apply an ejector to basic cycles has progressed actively. The role of the ejector and the performance of refrigeration cycles are subordinate to ejector locations. In this study, the performance of three refrigeration cycles with different ejector locations is compared and analyzed. The results showed an increased COP in all cycles due to the application of the ejector, with the highest increase of 44% compared to a basic refrigeration cycle. The ejector refrigeration cycle proposed in this study presents the highest COP, 3.47. Moreover, the decrease in condensation capacity in Bergander's cycle, Xing's cycle, and our proposed ejector refrigeration cycle went up to 21%. In refrigeration cycles applying the ejector, the pressure ratio of the ejector, the vapor fraction of discharge, and compression ratio are important factors for COP enhancement. For this reason, detailed and accurate control of these is significant.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5697-5699
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• 2014

Objective: To investigate the optimal timing of radiotherapy with alternating/sequential radio-chemotherapy for limited-stage small cell lung cancer (LS-SCLC). Methods: 91 patients with LS-SCLC were retrospectively analyzed and divided into two groups according to the number of chemotherapy cycles before radiotherapy. If the patient received radiotherapy after 3 cycles or fewer cycles of chemotherapy, classification was into the early group, if not, into the late group. All patients received 6 cycles of standard chemotherapy (EP/EC) and conventional radiotherapy (56 gy~ 60 gy/28 f ~30 f). Results: The response rate (RR) of the early and late groups were 85.7% and 81.6%, respectively, with no significant difference (p>0.05). In contrast, the progression-free survival (PFS) in the early group was better than that in the late group (11.8 months vs 9.86 months), and the difference was significant (p<0.05). There was no significant difference between two groups in adverse reactions, which gastrointestinal irritation and bone marrow suppression being the most common (p>0.05). Conclusions: Radiotherapy after 3 cycles or fewer cycles of chemotherapy does not bring significant benefits for RR of patients with LS-SCLC, but it could significantly prolong their PFS without increase in adverse reactions.