• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.196-198
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• 2003

검사점(checkpoint) 오버헤드를 최소화하는 검사점 주기(interval)를 결정하는 것은 결함 허용 시스템(fault tolerant system)에서 검사점 알고리즘과 관련된 많은 연구들의 중요한 목표 중의 하나이다. 검사점을 드물게 하게 되면 실패 후에 재수행 하는데 너무 많은 시간이 필요하게 된다. 반면에, 너무 자주하게 되면 검사점 오버헤드가 커지고 프로그램의 총 실행시간에 영향을 주게 된다. 이 논문에서는 적응성 있는(adaptive) 시계열 (time series) 분석을 사용하여 검사점 간격을 동적으로 조절할 수 있는 메모리 프로파일 검사점 간격 알고리즘을 제안한다. 트레이스에 기반한 시뮬레이션 실험 결과에서. 제안한 동적인 검사점 주기 알고리즘이 고정적인 검사점 주기 알고리즘보다 전체 검사점 오버헤드가 더 작고, 최적의 검사점 간격에 훨씬 근접했음을 알 수 있었다.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.123-135
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• 2012

Purpose: It is essential to minimize the movement of tumor due to respiratory movement at the time of respiration controlled radiotherapy of non-small cell lung cancer patient. Accordingly, this Study aims to evaluate the usefulness of restricted respiratory period by comparing and analyzing the treatment plans that apply free and restricted respiration period respectively. Materials and Methods: After having conducted training on 9 non-small cell lung cancer patients (tumor n=10) from April to December 2011 by using 'signal monitored-breathing (guided- breathing)' method for the 'free respiratory period' measured on the basis of the regular respiratory period of the patents and 'restricted respiratory period' that was intentionally reduced, total of 10 CT images for each of the respiration phases were acquired by carrying out 4D CT for treatment planning purpose by using RPM and 4-dimensional computed tomography simulator. Visual gross tumor volume (GTV) and internal target volume (ITV) that each of the observer 1 and observer 2 has set were measured and compared on the CT image of each respiratory interval. Moreover, the amplitude of movement of tumor was measured by measuring the center of mass (COM) at the phase of 0% which is the end-inspiration (EI) and at the phase of 50% which is the end-exhalation (EE). In addition, both observers established treatment plan that applied the 2 respiratory periods, and mean dose to normal lung (MDTNL) was compared and analyzed through dose-volume histogram (DVH). Moreover, normal tissue complication probability (NTCP) of the normal lung volume was compared by using dose-volume histogram analysis program (DVH analyzer v.1) and statistical analysis was performed in order to carry out quantitative evaluation of the measured data. Results: As the result of the analysis of the treatment plan that applied the 'restricted respiratory period' of the observer 1 and observer 2, there was reduction rate of 38.75% in the 3-dimensional direction movement of the tumor in comparison to the 'free respiratory period' in the case of the observer 1, while there reduction rate was 41.10% in the case of the observer 2. The results of measurement and comparison of the volumes, GTV and ITV, there was reduction rate of $14.96{\pm}9.44%$ for observer 1 and $19.86{\pm}10.62%$ for observer 2 in the case of GTV, while there was reduction rate of $8.91{\pm}5.91%$ for observer 1 and $15.52{\pm}9.01%$ for observer 2 in the case of ITV. The results of analysis and comparison of MDTNL and NTCP illustrated the reduction rate of MDTNL $3.98{\pm}5.62%$ for observer 1 and $7.62{\pm}10.29%$ for observer 2 in the case of MDTNL, while there was reduction rate of $21.70{\pm}28.27%$ for observer 1 and $37.83{\pm}49.93%$ for observer 2 in the case of NTCP. In addition, the results of analysis of correlation between the resultant values of the 2 observers, while there was significant difference between the observers for the 'free respiratory period', there was no significantly different reduction rates between the observers for 'restricted respiratory period. Conclusion: It was possible to verify the usefulness and appropriateness of 'restricted respiratory period' at the time of respiration controlled radiotherapy on non-small cell lung cancer patient as the treatment plan that applied 'restricted respiratory period' illustrated relative reduction in the evaluation factors in comparison to the 'free respiratory period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.713-720
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• 1998

Experiments on the control of rockfish, Sebastes inermis reproduction were performed by artificially changed water temperature (WT) and photoperiod (PP). The experiments were divided into three conditions; artificial changes of both WT and PP delayed two months against their natural variations (Exp.I), natural WT and PP replaced with artificial light (Exp.II) and natural WT and PP (Exp.III) from September to April (220 days). Initial gonadosomatic index (GSI) in female groups of experiments was 0.2. Female GSI of responded group in Exp.I began to increase from December and reached the highest value in February with 15.0, while the un-responded group kept the lower value during the experimental period. Female GSI of Exp.II and Exp.III reached the highest values in January with 13.0 and 14.7, respectively. Male GSI of Exp,I reached the maximum in October, and that of Exp.II and III reached the maximum in November and then rapidly decreased. Among the experimental groups, male GSI did not show the different tendency. Monthly changes of hepatosomatic index in both sexes showed the reciprocal tendency with those of GSI. The control of WT and PP did not affect on the changes of HSI and condition factor of rockfish. From the histological observations, maturation of ovary was delayed by the changes of WT and PP, but that of testis was not influenced. Judging from the above results, the maturation and parturition of female rockfish could be delayed one or two months by artificial changes of WT and PP.

• Radiation Oncology Journal
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• v.21 no.4
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• pp.306-314
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• 2003

Purpose : In our Previous study, we have shown the main cel1 death pattern Induced by irradiation or protein tyrosine kinase (PTK) inhibitors in K562 human myeiogenous leukemic cell line. Death of the cells treated with irradiation alone was characterized by mitotic catastrophe and typical radiation-induced apoptosis was accelerated by herblmycin A (HMA). Both types of cell death were inhibited by genistein. In this study, we investigated the effects of HMA and genistein on cell cycle regulation and its correlation with the alterations of radiation-induced cell death. Materials and Methods: K562 cells In exponential growth phase were used for this study. The cells were Irradiated with 10 Gy using 6 MeV Linac (200-300 cGy/min). Immediately after irradiation, cells were treated with 250 nM of HMA or 25 $\mu$N of genistein. The distributions of cell cycle, the expressions of cell cycle-related protein, the activities of cyclin-dependent kinase, and the yield of senescence and differentiation were analyzed. Results: X-irradiated cells were arrested In the G2 phase of the cell cycle but unlike the p53-positive cells, they were not able to sustain the cell cycle arrest. An accumulation of cells in G2 phase of first ceil-cycle post-treatment and an increase of cyclin Bl were correlated with spontaneous, premature, chromosome condensation and mitotic catastrophe. HMA induced rapid G2 checkpoint abrogation and concomitant p53-independent Gl accumulation. HMA-induced cell cycle modifications correlated with the increase of CDK2 kinase activity, the decrease of the expressions of cyclins I and A and of CDK2 kinase activity, and the enhancement of radiation-induced apoptosis. Genistein maintained cells that were arrested in the G2-phase, decreased the expressions of cyclin Bl and cdc25c and cdc25C kinase activity, increased the expression of pl6, and sustained senescence and megakaryocytic differentiation. Conclusion: The effects of HMA and genistein on the radiation-induced cell death of KS62 cells were closely related to the cell cycle regulatory activities. In this study, we present a unique and reproducible model in which for investigating the mechanisms of various, radiation-induced, cancer cell death patterns. Further evaluation by using this model will provide a potent target for a new strategy of radiotherapy.

• 순환기질환의공학회:학술대회논문집
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• 2006.10a
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• pp.1-2
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• 2006

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.417-425
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• 2017

Cnidium monnieri (L.) Cusson is distributed in China and Korea, and the fruit of C. monnieri is used as traditional Chinese medicine to treat carbuncle and pain in female genitalia. In this study, we examined the anti-proliferation and cell cycle arrest effects of ethanol extracts from C. monnieri (CME) in AGS gastric cancer cells. Our results show that CME suppressed cell proliferation and induced release of lactate dehydrogenase (LDH) in AGS cells by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay and LDH assay. Cell morphology was altered by CME in a dose-dependent manner. In order to identify the cell cycle arrest effects of CME, we investigated cell cycle analysis after CME treatment. In our results, CME induced cell cycle arrest at G1 phase. Protein kinase B (Akt) plays a major role in cell survival mechanisms such as growth, division, and metastasis. Akt protein regulates various downstream proteins such as glycogen synthase kinase-$3{\beta}$ (GSK-$3{\beta}$) and tumor protein p53 (p53). Expression levels of p-Akt, p-GSK-$3{\beta}$, p53, p21, cyclin E, and cyclin-dependent kinase 2 (CDK2) were determined by Western blot analysis. Protein levels of p-Akt, p-GSK-$3{\beta}$, and cyclin E were reduced while those of p53, p21, and p-CDK2 (T14/Y15) were elevated by CME. Moreover, treatment with CME, LY294002 (phosphoinositide 3-kinase/Akt inhibitor), BIO (GSK-$3{\beta}$ inhibitor), and Pifithrin-${\alpha}$ (p53 inhibitor) showed that cell cycle arrest effects were mediated through regulation of the Akt/GSK-$3{\beta}$/p53 signaling pathway. These results suggest that CME induces cell cycle arrest at G1 phase via the Akt/GSK-$3{\beta}$/p53 signaling pathway in AGS gastric cancer cells.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.143-149
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• 2019

This study was conducted to investigate the graft-taking and growth of grafted cucumber seedlings as affected by light quality and blink cycle of LED modules. Four light quality treatments, namely blue, red, blue+red, white LED and four blink cycle levels of 5s/5s, 7s/3s, 9s/1s and control were provided to investigate the effect of lighting quality and blink cycle on the graft-taking and growth of grafted cucumber seedlings. Photoperiod for the control was 12/12 h. Photosynthetic photon flux, air temperature, and relative humidity for healing were maintained at $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $25^{\circ}C$, and 90%, respectively. There was no significant difference in graft-taking of grafted cucumber seedlings according to light quality except the blue LED with the blink cycle of 5s/5s. Regardless of the blink cycle, there was no significant difference in graft-taking of cucumber seedlings healed under red, blue+red, and white LED modules. These results implied that the effects of light quality and blink cycle on the graft-taking were not significant. Differences in the leaf length, leaf area, and fresh weight of cucumber seedlings healed blue or red LED with the blink cycle of 9s/1s were found to be significant. There was no significant effect of the blink cycle on the growth of cucumber seedlings healed under white LED modules. The prices of white LED are gradually falling due to increased demand. Considering the manufacturing unit price of white LED modules, the cost savings of 10-15% are expected as compared to the conventional blue/red LED modules. Therefore, it was concluded that the use of white LED modules will be economical as an artificial lighting sources for healing of grafted seedlings.

• The KIPS Transactions:PartD
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• v.17D no.3
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• pp.185-192
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• 2010

In sensor network environments, each sensor measures the physical environments according to the sampling period, and transmits a sensor reading to the base station. Thus, the sample period influences against importance resources such as a network bandwidth, and a battery power. In this paper, we propose new adaptive sampling technique that adjusts the sampling period of a sensor with respect to the features of sensor readings. The proposed technique predicts a future readings based on KF (Kalman Filter). By using the differences of actual readings and estimated reading, we identify the importance of sensor readings, and then, we adjust the sampling period according to the importance. In our experiments, we demonstrate the effectiveness of our technique.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.1
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• pp.42-48
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• 2003

To get a periodic trim solution from Level II helicopter flight dynamic equations, DAE based PPT A (partial Periodic Trimming Algorithm) has been proposed. Iterative update of state variables from PPT A can cause a numerical instability in DAE solver which needs compatible initial conditions. By simply adjusting the order of DAE solver a periodic trim can be obtained with good accuracy. Application for CBM (Common Baseline Model) helicopter showed the same trim result as harmonic balance method and the effective elimination of unrealistic initial responses at the start of flight simulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.137-140
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• 2004

Oscillating heat release associated with periodic vortex-flame interaction was investigated experimentally. Turbulent jet flames were stabilized with recirculating hot products in a dump combustor, and large-scale periodic vortices were imposed into the jet flame by acoustic forcing. Forcing frequencies and operating parameters were adjusted to simulate unstable combustor operation in practical combustors. The objectives were to characterize vortex-heat release interaction that leads to unwanted heat release fluctuations and to identify the proper fuel injection pattern that could be used for actively suppressing such fluctuations. Phase-resolved CH* chemiluminescence and schlieren images were used as diagnostic tools. The results were compared at corresponding phases of vortex shedding cycle.