• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1379-1382
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• 2003

Recently, mobile embedded systems used widly in various applications. Managing power consumption is becoming a matter of primary concern because those systems use limited power supply. As an approach reduce power consumption, voltage can be scaled down. according to the execution time and deadline. By reducing the supplying voltage to 1/N power consumption can be reduced to 1/N. DPM-S is a well known method for dynamic voltage scaling. In this paper, we enhanced DPM-S by using average execution time aggressively. The frequency of processor is calculated based in average execution time instead of worst case execution time. Simulation results show that our method achieve up to 5％ energy savings than DPM-S.

• Food Science and Preservation
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• v.8 no.2
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• pp.157-163
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• 2001

Optimal conditions for hot water extraction of Liriope spicata tuber were investigated with changes in solvent ratio(2∼6 fold) and heating time(1∼5 hr) by response surface methodology. The content of extractable solids increased with an increased in solvent ratio, and the highest content showed at heating time of 3 hr. The content of total steroid saponin increased with a decrease in solvent ratio, and increased with an increase in heating time at increasing the solvent ratio. The content of non-reducing sugar containing oligosaccharides at a lower solvent ratio didn’t show changes depending on heating time, while that at a higher ration decreased with an increase in heating time. Optimal extraction conditions using hot water as the limited conditions of 15∼18% extractable solids, 1.5∼2.0% total steroid saponin, 6∼8% reducing sugar, 6∼7% non-reducing sugar and 13∼15 brix were 3 hrs of heating time and 4 fold of solvent ratio.

• Journal of the Korea Computer Graphics Society
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• v.11 no.1
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• pp.40-49
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• 2005

Several optimization techniques have been proposed for volume ray casting, but these cannot achieve real-time frame rates. In addition, it is difficult to apply them to some applications that require perspective projection. Recently, hardware-based methods using 3D texture mapping are being used for real-time volume rendering. Although rendering speed approaches real time, the larger volumes require more swapping of volume bricks for the limited texture memory. Also, image quality deteriorates compared with that of conventional volume ray casting. In this paper, we propose a data structure for real-time volume ray casting named PERM (Precomputed dEnsity and gRadient Map). The PERM stores interpolated density and gradient vector for quantized cells. Since the information requiring time-consuming computations is stored in the PERM, our method can ensure interactive frame rates on a consumer PC platform. Our method normally produces high-quality images because it is based on conventional volume ray casting.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.3
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• pp.164-175
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• 2010

In this study, we developed a genetic algorithm to find a near optimal solution of concurrent spare parts selection for the operational time period with limited information of weapon systems purchased from overseas. Through the analysis of time profiles related with system operations, we first define the optimization goal which maintains the expected system operating rate under the budget restrictions, and the number of failures and the lead time for each spare part are used to calculate the estimated total down time of the system. The genetic algorithm for CSP selection shows that the objective function minimizes the estimated total down time of systems with satisfying the restrictions. The method provided by this study can be applied to the generalized model of CSP selection for the systems purchased from overseas without provision of their full structure and adequate information.

• Journal of the Korean Society of Systems Engineering
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• v.19 no.2
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• pp.145-156
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• 2023

Trajectory of ballistic missile is defined by inherent flight dynamics, which decided range and maneuvering characteristics. It is crucial to predict range and maneuvering characteristics of ballistic missile in KAMD (Korea Air and Missile Defense) to minimize damage due to ballistic missile attacks, Nowadays, needs for applying AI(Artificial Intelligence) technologies are increasing due to rapid developments of DNN(Deep Neural Networks) technologies. To apply these DNN technologies amount of data are required for superviesed learning, but trajectory data of ballistic missiles is limited because of security issues. Trajectory data could be considered as multivariate time series including many variables. And augmentation in time series data is a developing area of research. In this paper, we tried to augment trajectory data of ballistic missiles using recently developed methods. We used TimeVAE(Time Variational AutoEncoder) method and TimeGAN(Time Generative Adversarial Networks) to synthesize missile trajectory data. We also compare the results of two methods and analyse for future works.

• Journal of Ecology and Environment
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• v.41 no.11
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• pp.310-317
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• 2017

Background: Many studies about climate-related range shift of plants have focused on understanding the relationship between climatic factors and plant distributions. However, consideration of adaptation factors, such as dispersal and plant physiological processes, is necessary for a more accurate prediction. This study predicted the future distribution of marlberry (Ardisia japonica), a warm-adapted evergreen broadleaved shrub, under climate change in relation to the dispersal ability that is determined by elapsed time for the first seed production. Results: We introduced climate change data under four representative concentration pathway (RCP 2.6, 4.5, 6.0, and 8.5) scenarios from five different global circulation models (GCMs) to simulate the future distributions (2041~2060) of marlberry. Using these 20 different climate data, ensemble forecasts were produced by averaging the future distributions of marlberry in order to minimize the model uncertainties. Then, a dispersal-limited function was applied to the ensemble forecast in order to exam the impact of dispersal capacity on future marlberry distributions. In the dispersal-limited function, elapsed time for the first seed production and possible dispersal distances define the dispersal capacity. The results showed that the current suitable habitats of marlberry expanded toward central coast and southern inland area from the current southern and mid-eastern coast area in Korea. However, given the dispersal-limited function, this experiment showed lower expansions to the central coast area and southern inland area. Conclusions: This study well explains the importance of dispersal capacity in the prediction of future marlberry distribution and can be used as basic information in understanding the climate change effects on the future distributions of Ardisia japonica.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.6
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• pp.472-477
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• 2000

Oxides of the form Mn$_{4}$/O$_{4}$-CuO-Co$_{3}$/O$_{4}$-NiO-ZnO present properties that make them useful as power NTC thermistor for current limited. Electrical properties of Mn$_{3}$/O$_{4}$-CuO-Co$_{3}$/O$_{4}$-CuO-Co$_{3}$/O$_{4}$-NiO-ZnO power NTC thermistor such as I-V characteristics tim constant activation energy and heat dissipation coefficient measured as a function of temperature and composition. In Mn$_{4}$/O$_{4}$-CuO-Co$_{3}$/O$_{4}$-NiO-ZnO system with the 5wt% addition of Co$_{3}$/O$_{4}$ it can be seen that resistivity and B-constant were increased as the ratio of ZnO/Mn$_{3}$/O$_{4}$ was increased. Heat dissipation constant, I-V characteristics and time constant showed similar behaviour compared with those of conventional thermistors. In particular resistance change ratio ($\Delta$R) the important factor for reliability varied within $\pm$5% indicating the compositions of these products could be available for power thermistor.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.389-394
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• 2008

The purpose of this research was to develop a methodology to determine whether conjunctive surface water and groundwater management could significantly reduce deficits in a river basin with a relatively limited alluvial aquifer. The Geum River basin is one of major river basins in South Korea. The upper region of the Geum River basin is typical of many river basins in Korea where the shape of river basin is narrow with small alluvial aquifer depths from 10m to 20m and where most of the groundwater pumped comes quickly from the steamflow. The basin has two surface reservoirs, Daecheong and Yongdam. The most recent reservoir, Yongdam, provides water to a trans-basin diversion, and therefore reduces the water resources available in the Geum River basin. After the completion of Yongdam reservoir, the reduced water supply in the Geum basin resulted in increasing conflicts between downstream water needs and required instream flows, particularly during the low flow season. Historically, the operation of groundwater pumping has had limited control and is administered separately from surface water diversions. Given the limited size of the alluvial aquifer, it is apparent that groundwater pumping is essentially taking its water from the stream. Therefore, the operation of the surface water withdrawals and groundwater pumping must be considered together. The major component of the conjunction water management in this study is a goal-programmin g based optimization model that simultaneously considers surface water withdrawals, groundwater pumping and instream flow requirements. A 10-day time step is used in the model. The interactions between groundwater pumping and the stream are handled through the use of response and lag coefficients. The impacts of pumping on streamflow are considered for multiple time periods. The model is formulated as a linear goal-programming problem that is solved with the commercial LINGO optimization software package.

• Journal of Korean Academy of Nursing
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• v.43 no.2
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• pp.145-153
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• 2013

Purpose: The purpose of this manuscript is to discuss the need for use of evidence based practice (EBP) in LTC, the current use of evidence in long term care facilities and what we know about adoption of the use of EBP in LTC. Methods: Literature review and reporting of findings from the M-TRAIN study that was a quasi-experimental design to test the effectiveness of an intervention to increase the use of EBPs for urinary incontinence and pain in 48 LTC facilities. Results: Barriers to adopting EBPs include lack of available time, lack of access to current research literature, limited critical appraisal skills, excessive literature to review, non-receptive organizational culture, limited resources, and limited decision-making authority of staff to implement change. Strategies to promote adoption of EBP include the commitment of management; the culture of the home; leadership; staff knowledge, time, and reward; and facility size, complexity, the extent that members are involved outside the facility, NH chain membership, and high level of private pay residents. Findings from the M-TRAIN add, stability of nurse leader and congruency between the leaders perception of their leadership and the staff's perception of the leadership. Conclusion: There is clear evidence of the need and the benefits to residents of LTC and to the health care system yet adoption of EBP continues to be slow and sporadic. There is also evidence for the process of establishing best evidence and many resources to find the available EBPs. The urgent need now is finding ways to best get the EBPs implemented in LTC. There is growing evidence about best methods to do this but continued research is needed. Clearly, residents in LTC deserve the best care possible and EBPs represent an important vehicle by which to do this.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.369-373
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• 1998

The bullectomy through the limited transaxillary thoracotomy and video-assisted thoracic surgery(VATS) had been used in operative management of spontaneous pneumothorax from Jan. 1994 to July 1997. The study comprised a retrospective review of 42 cases which were treated by limited thoracotomy, and 61 cases treated by video-assisted thoracoscopic sugery. We retrospectively reviewed annual incidnce of bullectomy. Analysis of video-assised thoracoscopic surgery and open bullectomy including age, sex, operative sites, surgical indications, associated diseases, operative time, posoperatve complications and hospital courses. There was no significant difference for operation time in two groups, 98.3${\pm}$38.4 minutes in thoracotomy and 95.7${\pm}$31.5 minutes in VATS. Prolonged air leakage over 7 days was observed in 8 cases from thoracotomy group, 4 cases from VATS group. 3 cases of recurrent pneumothorax were found from VATS group, but no recurrence was occurred from open bullectomy group. There were significant differences in postoperative hospital stay (8.0${\pm}$3.9 day in thoracotomy vs 5.9${\pm}$2.4day in VATS(P=0.001)), and indwelling period of chest tube after operation( 5.8${\pm}$3.0day in thoracotomy vs 4.0${\pm}$2.0day in VATS(P=0.0006)).