• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.177-184
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• 2009

For the purpose of reducing the cost for greenhouse operation by acquiring the electric power necessary for it, this study installed a solar photovoltaic system on the roof of the building adjacent to green-houses and experimentally examined the quantity of power generation based on weather conditions. The results of the study are as per the below: The maximum, average and minimum temperature while the experiment was conducted was $0.4{\sim}34.1,\;-6.1{\sim}22.2$, and $-14.1{\sim}16.7^{\circ}C$ respectively, and the solar radiation was $28.8MJ{\cdot}m^{-2}$ (maximum), $14.9MJ{\cdot}m^{-2}$ (average), and $0.6MJ{\cdot}m^{-2}$ (minimum). The quantity of electric power didn't increase in proportion to the quantity of solar radiation and instead, it was almost consistent around 750W. Daily maximum, average and minimum consumption of electric power was 5.2kWh, 2.5kWh and 0kWh respectively. Based on the average electric power consumption of the system used for this experiment, it was sufficient in case the capacity and the working time of a hot blast heater are small, but it was short in case they are big. In case the capacity of the hot blast heater is big, the average electric power quantity will be sufficient for array area $21m^2$, about three times of the present area. In summer when the temperature of the array becomes high, the generation of electric power didn't increase in proportion to the quantity of solar radiation, but this experiment result shows a high correlation between two factors (coefficient of correlation 0.84).

• Journal of radiological science and technology
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• v.32 no.4
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• pp.361-370
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• 2009

The image quality management of bone mineral density is the responsibility and duty of radiologists who carry out examinations. However, inaccurate conclusions due to lack of understanding and ignorance regarding the methodology of image quality management can be a fatal error to the patient. Therefore, objective of this paper is to understand proper image quality management and enumerate methods for examiners and patients, thereby ensuring the reliability of bone mineral density exams. The accuracy and precision of bone mineral density measurements must be at the highest level so that actual biological changes can be detected with even slight changes in bone mineral density. Accuracy and precision should be continuously preserved for image quality of machines. Those factors will contribute to ensure the reliability in bone mineral density exams. Proper equipment management or control methods are set with correcting equipment each morning and after image quality management, a phantom, recommended from the manufacturer, is used for ten to twenty-five measurements in search of a mean value with a permissible range of ${\pm}1.5%$ set as standard. There needs to be daily measurement inspections on the phantom or at least inspections three times a week in order to confirm the existence or nonexistence of changes in values in actual bone mineral density. in addition, bone mineral density measurements were evaluated and recorded following the rules of Shewhart control chart. This type of management has to be conducted for the installation and movement of equipment. For the management methods of inspectors, evaluation of the measurement precision was conducted by testing the reproducibility of the exact same figures without any real biological changes occurring during reinspection. Bone mineral density inspection was applied as the measurement method for patients either taking two measurements thirty times or three measurements fifteen times. An important point when taking measurements was after a measurement whether it was the second or third examination, it was required to descend from the table and then reascend. With a 95% confidence level, the precision error produced from the measurement bone mineral figures came to 2.77 times the minimum of the biological bone mineral density change. The value produced can be stated as the least significant change (LSC) and in the case the value is greater, it can be stated as a section of genuine biological change. From the initial inspection to equipment moving and shifter, management must be carried out and continued in order to achieve the effects. The enforcement of proper quality control of radiologists performing bone mineral density inspections which brings about the durability extensions of equipment and accurate results of calculations will help the assurance of reliable inspections.

• Membrane Journal
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• v.30 no.3
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• pp.181-189
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• 2020

In the present study, a biomimetic alumina membrane was fabricated by using selenic acid as an electrolyte to overcome the asymmetry limit of the square pulse anodization process. The prepared membrane has conical channels with a minimum diameter of 10 nm, a maximum diameter of 50 nm, and a length of 5 ㎛. The rectification property was higher than membranes fabricated by sulfuric acid. It showed 2.9 times larger current at +1 V than -1 V. Also, the membrane, which sulfonic acid group was introduced by surface modification, showed 4.2 times larger rectification property at -1 V than +1 V. Theoretical verifications were supported by the numerical analyses of 2D models. The results of the present study present a convenient method to fabricate two type membranes with different rectification properties and are expected to be used to control ion transport.

• Nuclear Engineering and Technology
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• v.14 no.4
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• pp.186-195
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• 1982

The steam line break accident for Kori Unit 1 is analyzed by a code SYSRAN which calculates nuclear power and heat flux using the point kinetics equation and the lumped-parameter model and calculates system transient using the mass and energy balance equation with the assumption of uniform reactor coolant system pressure. The 1.4 f $t^2$ steam line break accident is analyzed at EOL (End of Life), hot shutdown condition in which case the accident would be most severe. The steam discharge rate is assumed to follow the Moody critical flow model. The results reveal the peak heat flux of 38% of nominal full power value at 60 second after the accident initiates, which is higher than the FSAR result of 26%. Trends for the transient are in good agreement with FSAR results. A sensitivity study shows that this accident is most sensitive to the moderator density coefficient and the lower plenum mixing factor. The DNBR calculation under the assumption of $F_{{\Delta}H}$=3.66, which is used in the FSAR with all the control and the shutdown assemblies inserted except one B bank assembly and of Fz=1.55 shows that minimum DNBR reaches 1.62 at 60 second, indicating that the fuel failure is not anticipated to occur. The point kinetics equation, the lumped-parameter model and the system transient model which uses the mass and energy balance equation are verified to be effective to follow the system transient phenomena of the nuclear power plants.lear power plants.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.786-791
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• 2007

Korean high speed train(HSR-350x) has adopted a combined electrical and mechanical(friction) braking system. Brake blending control unit(BBCU) controls each brake system to fulfill the required brake performances such as braking distance, deceleration and jerk. Also the braking system should be designed considering the economical management, such as effective use of generated braking energy and the minimum wear of friction materials(a pad and a brake shoe). In this paper, we establish the disc braking force pattern that reduces the wear of pad in the disc braking system by minimizing the variance of the instantaneous disk baking energy during braking time, and compare the wear mass of pad between the conventional disc braking force pattern and the established results.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.2
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• pp.47-56
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• 2015

In an energy saving server cluster environment, the power modes of servers are controlled according to load situation, that is, by making ON only minimum number of servers needed to handle current load while making the other servers OFF. This algorithm works well under normal circumstances, but does not guarantee QoS under abnormal circumstances such as sharply rising or falling loads. This is because the number of ON servers cannot be increased immediately due to the time delay for servers to turn ON from OFF. In this paper, we propose a new prediction algorithm of the power consumption for improving QoS under not only normal but also abnormal circumstances. The proposed prediction algorithm consists of two parts: prediction based on the conventional time series analysis and prediction adjustment based on trend analysis. We performed experiments using 15 PCs and compared performance for 4 types of conventional time series based prediction methods and their modified methods with our prediction algorithm. Experimental results show that Exponential Smoothing with Trend Adjusted (ESTA) and its modified ESTA (MESTA) proposed in this paper are outperforming among 4 types of prediction methods in terms of normalized QoS and number of good reponses per power consumed, and QoS of MESTA proposed in this paper is 7.5% and 3.3% better than that of conventional ESTA for artificial load pattern and real load pattern, respectively.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.605-611
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• 2019

The purpose of this study is to manufacture a multi-function device (MFD) which can be applied to various types of weight-bearing view of the lower leg, and to compare the results with the images from the existing weight-bearing platforms (WBPs), thereby suggesting a clinical utilization. The MFD was manufactured, by considering the minimum adjustable heights of the platform for weight-bearing foot/ankle, platform for hindfoot alignment view, and X-ray tube of the X-ray device. A foot/ankle phantom was used to take the images of weight-bearing lateral foot in MFD and WBPs to compare the resolutions of the X-ray images using a quick modulation transfer function (MTF) program. Between both the images taken from the MFD and WBPs, there was no statistically significant difference found in the mean cycles per pixel (C/P) and the lines per image height (LPH) of the 50%-Contrast Spatial Frequency (MTF50), and 10-90% of Maximum Energy Rise Distance (10-90%), where p>0.05. The MFD is suggested for its clinical trial as a useful positioning device that can secure the patient's safety and manifoldly perform various inspections. Also, the recommendation of the positioning device as a policy can activate dedicated manufacturers, while also improving the quality of medical services.

• Animal Bioscience
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• v.35 no.10
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• pp.1545-1555
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• 2022

Objective: Our study aimed to investigate the effects of a 2% increase in dietary total digestible nutrients (TDN) value during the growing (7 to 12 mo of age) and fattening (13 to 30 mo of age) period of Hanwoo steers. Methods: Two hundred and twenty Hanwoo steers were assigned to one of two treatments: i) a control group (basal TDN, BTDN, n = 111 steers, growing = 70.5%, early fattening = 71.0%, late fattening = 74.0%) or high TDN (HTDN, n = 109 steers, growing = 72.6%, early = 73.1%, late = 76.2%). Growth performance, carcass traits, blood parameters, and gene expression of longissimus dorsi (LD) (7, 18, and 30 mo) were quantified. Results: Steers on the BTDN diets had increased (p≤0.02) DMI throughout the feeding trial compared to HTDN, but gain did not differ appreciably. A greater proportion of cattle in HTDN received Korean quality grade 1 (82%) or greater compared to BTDN (77%), while HTDN had a greater yield grade (29%) than BTDN (20%). Redness (a^*) of LD muscle was improved (p = 0.021) in steers fed HTDN. Feeding the HTDN diet did not alter blood parameters. Steers fed HTDN diet increased (p = 0.015) the proportion of stearic acid and tended to alter linoleic acid. Overall, saturated, unsaturated, monounsaturated, and polyunsaturated fatty acids of LD muscle were not impacted by the HTDN treatment. A treatment by age interaction was noted for mRNA expression of myosin heavy chain (MHC) IIA, IIX, and stearoyl CoA desaturase (SCD) (p≤0.026). No treatment effect was detected on gene expression from LD muscle biopsies at 7, 18, and 30 mo of age; however, an age effect was detected for all variables measured (p≤0.001). Conclusion: Our results indicated that feeding HTDN diet could improve overall quality grade while minimum effects were noted in gene expression, blood parameters, and growing performance. Cattle performance prediction in the feedlot is a critical decision-making tool for optimal planning of cattle fattening and these data provide both benchmark physiological parameters and growth performance measures for Hanwoo cattle feeding enterprises.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.251-258
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• 1998

Purpose : This study was performed to analyze the factors affecting local control in malignant tumors of the parotid gland treated with surgery and postoperative radiation. Materials and methods : Twenty-six patients were treated for malignant tumors of the parotid gland from 1986 to 1995 at Department of Therapeutic Radiology, Chonnam University Hospital. Age of the patients ranged from 14 to 72 years (median : 55 years). Histologically 10 patients of mucoepidermoid carcinoma, 7 of squamous cell carcinoma, 4 of acinic cell carcinoma, 4 of adenoid cystic carcinoma and 1 of adenocarcinoma were treated. Total parotidectomy was performd in 15 of 26 patients, superficial in 7, subtotal in 4. Facial nerve was sacrificed in 5 patients. Postoperatively 4 patients had residual disease, 4 had positive resection margin. Radiation was delivered through an ipsilateral wedged pair of photon in 11 patients. High energy electron beam was mixed with photon in 15 patients. Electron beam dose ranged from 900 cGy to 3800 cGy (median 1700 cGy). Total radiation dose ranged from 5000 cGy to 7560 cGy (median : 6020 cGy). Minimum follow-up period was 2 years. Local control and survival rate were calculated using Kaplan-Meier method. Generalized Wilcoxon test and Cox proportional hazard model were used to test factors affecting local control. Results : Five (19$\%$) of 26 patients had local recurrence. Five year local control rate was 77$\%$. Overall five year survival rate was 70$\%$. Sex, age, tumor size, surgical involvement of cervical lymph node, involvement of resection margin, surgical invasion of nerve, and total dose were analyzed as suggested factors affecting local control rate. Among them patients with tumor size less than 4 cm (p=0.002) and negative resection margin (p=0.011) were associated with better local control rates in univariate analysis. Multivariate analysis showed only tumor size factor is associated with local control rate (p=0.022). Conclusion : This study suggested that tumor size is important in local control of malignant tumors of parotid gland.

• Journal of Bio-Environment Control
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• v.7 no.1
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• pp.25-33
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• 1998

Root zone temperature have influenced on protected cultivation in winter season. Especially root zone temperature is acted on limiting factor in crop cultivation. This study was conducted to obtain optimum temperature of root zone in Protected cultivation Root zone was warmed by heated water($28^{\circ}C$) flowing through the PPC pipe(${\phi}15$) buried depth 40 cm. And the flowing water was heated by solar system. Minimum air temperature during night time was set at $14^{\circ}C$ and maximum air temperature during day time was set at $28~30^{\circ}C$ the growing period of cucumber was from Nov. 6, 1996 to Jan. 30, 1997. The results are summarized as follows. 1. Average soil temperature at 15~20 cm depth was $22^{\circ}C$ at warming plots, $17~18^{\circ}C$ at non-warming plots 2. Early growth in leaf length, stem diameter, number of leaves and leaf area for 30 days after planting were accelerated by root zone warming. Especially, the grawing rate of soil warming plots was higher 27% in leaf length, 51% in leaf number, 150% in leaf area than non-warming Plots. Above-ground and underground part of warming plots was higher 117%, 56% than non-warming plots. 3. In total yield analysis, number of fruits were 614 in soil warming and 313 in non-warming plots. In the result, total yield of soil warming plots was increased with 196% than non-warming plots. 3. In total yield analysis. number of fruits were 614 in soil warming and 313 in non-warming plots. In the result. total yield of soil warming plots was increased with 196% than non-warming plots.