• Journal of Environmental Science International
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• v.23 no.10
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• pp.1755-1762
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• 2014

Water quality of the Koejong-reservoir was estimated by using the ecological model to evaluate the effects of industrial sewage discharge. State variables consist of POC, DOC, phytoplankton, DIP, DIN, DO and COD. Initial conditions for the compartment are applied to the model based on the observed results. The reproducibility was found to be satisfactory with the relative error ranging between the calculated value and the observed value. Water quality simulation was conducted by applying additional industrial sewage discharge into the Koejong-reservoir. The concentrations of COD, Chl.a, DIP and COD showed fluctuations of a narrow range. The increment percentages of Chl.a, COD and DIP were 26.6%, 20.2% and 18.2%, respectively. In the case of DO, the concentration decreased 4.8%.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.232-238
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• 2011

In the present study, Taguchi method is used to determine the rough region first, followed by RSM technique to determine the exact optimum value during milling on a machining center. A region reducing algorithm is applied to narrow down the region of the Taguchi method for RSM. The result from the Taguchi method is fed to train the artificial neural network (ANN), whose optimum value is used to drive the region reducing algorithm. The proposed algorithm is tested under different cutting condition and results show that the introduced algorithm works well during milling process. It is also shown that theoretically obtained optimal cutting condition is very close to experimentally obtained result.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.655-657
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• 2003

This study is on the characteristics of discriminating of image using unique electric wave intensity value from satellite images data. Namely this study is on studying specific image characteristics by image spectrum and is on developing procedures discriminating of water, forest. narrow-leaved(coniferous) trees, broad-leaved(deciduous) trees, terrain, farmland, grassland, etc. using unique spectrum value in material. Finally applying this procedures, we design and implement discriminating system, IDEA(Information Discriminating Extracting Agent).

• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.73-80
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• 2019

In this paper, we propose an effective dynamic range compression (DRC) method of infrared images. A histogram of infrared images has narrow dynamic range compared to visible images. Hence, it is important to apply the effective DRC algorithm for high performance of an infrared image analysis. The proposed algorithm for high dynamic range divides an infrared image into the overlapped blocks and calculates Shannon's entropy of overlapped blocks. After that, we classify each block according to the value of entropy and apply adaptive histogram modification method each overlapped block. We make an intensity mapping function through result of the adaptive histogram modification method which is using standard-deviation and maximum value of histogram of classified blocks. Lastly, in order to reduce block artifact, we apply hanning window to the overlapped blocks. In experimental result, the proposed method showed better performance of dynamic range compression compared to previous algorithms.

• Progress in Medical Physics
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• v.7 no.1
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• pp.53-64
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• 1996

Purpose: The purposes of this paper are to develop a theoretical basis that the beam directions should be considered when the mechanical accuracy of teletherapy machine is evaluated by the star pattern test, to develop methods using asymmetric field in length to simulate beam direction for the case that beam direction does not appear on film. Method: In evaluating mechanical rotational accuracy of the gantry of teletherapy unit by the star pattern test, the direction of radiation beams was considered. A star pattern using some narrow beams was made. Density profiles at 10cm far from estimated gantry axis on the star pattern were measured using an optical densitometer. On each profile, one coordimate of a beam axis was determined. A pair of coordinates on a beam axis form an equation of the axis. Assume that a unit vector equation omitted is with same direction as radiation beam and a vector equation omitted is a vector directing to the beam axis from the estimated gantry axis. Then, a vector product equation omitted ${\times}$ equation omitted is an area vector of which the absolute value is equal to the distance from the estimated gantry axis to the beam axis. The coordinate of gantry axis was obtained by using least-square method for the area vectors relative to the average of whole area vectors. For the axis, the maximum of absolute value of area vectors would be an accuracy of the gantry rotation axis. For the evaluation of mechanical accuracies of collimator and couch axes for which beam direction could not be depicted on a star pattern test film, narrow beams asymmetric in field length was used to simulate beam direction. Result: For a star test pattern to evaluate the mechanical accuracy of rotational axes of a telectherapy machine, the result considering beam direction was different from that ignoring beam direction. For the evaluation of mechanical accuracies of collimator and couch axes by means of a star pattern test, narrow asymmetric beams could simulate beam direction. Conclusion: When a star pattern test is used to evaluate the mechanical accuracy of a teletherapy unit, beam direction must be considered or simulated, and quantitatively evaluated.

• Journal of Radiation Industry
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• v.10 no.1
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• pp.29-35
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• 2016

Radiation generating devices must be properly shielded for their safe application. Although institutes such as US National Bureau of Standards and National Council on Radiation Protection and Measurements (NCRP) have provided guidelines for shielding X-ray tube of various purposes, industry people tend to rely on 'Half Value Layer (HVL) method' which requires relatively simple calculation compared to the case of those guidelines. The method is based on the fact that the intensity, dose, and air kerma of narrow beam incident on shielding wall decreases by about half as the beam penetrates the HVL thickness of the wall. One can adjust shielding wall thickness to satisfy outside wall dose or air kerma requirements with this calculation. However, this may not always be the case because 1) The strict definition of HVL deals with only Intensity, 2) The situation is different when the beam is not 'narrow'; the beam quality inside the wall is distorted and related changes on outside wall dose or air kerma such as buildup effect occurs. Therefore, sometimes more careful research should be done in order to verify the effect of shielding specific radiation generating device. High energy X-ray tubes which is operated at the voltage above 400 kV that are used for 'heavy' nondestructive inspection is an example. People have less experience in running and shielding such device than in the case of widely-used low energy X-ray tubes operated at the voltage below 300 kV. In this study, Air Kerma value per week, outside concrete shielding wall of various thickness surrounding 450 kVp X-ray tube were calculated using MCNP simulation with the aid of Geometry Splitting method which is a famous Variance Reduction technique. The comparison between simulated result, HVL method result, and NCRP Report 147 safety goal $0.02mGy\;wk^{-1}$ on Air Kerma for the place where the public are free to pass showed that concrete wall of thickness 80 cm is needed to achieve the safety goal. Essentially same result was obtained from the application of HVL method except that it suggest the need of additional 5 cm concrete wall thickness. Therefore, employing the result from HVL method calculation as an conservative upper limit of concrete shielding wall thickness was found to be useful; It would be easy, economic, and reasonable way to set shielding wall thickness.

• The Journal of Industrial Distribution & Business
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• v.11 no.10
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• pp.17-25
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• 2020

Purpose: The purpose of this study is to narrow the target down to college students representing single-person households to identify the main attributes of their choice of Home Meal Replacement(HMR) and to look at the impact on satisfaction and repurchase intentions. Research design, data and methodology: An online survey was conducted for consumers who purchased HMR products at least once and a total of 264 questionnaires were used for demonstration analysis. The collected data have verified for validity and reliability between measurement variables through exploratory factor analysis and reliability analysis. Results: As a result, curiosity, economy, safety, and brand, which are HMR selection attributes that university students' value, have a significant impact on satisfaction, and satisfaction has a significant impact on the intention of repurchase, a variable of behavior. In addition, the adjustment effect of health value pursuit was significant only in safety attributes. Conclusions: This study divided the target group to examine what the HMR selection attributes of single-person college students are, the main consumer of HMR, and how selective attributes affect satisfaction and willingness to repurchase. In the process, we wanted to find out if there was a moderating effect on the health-oriented values in the dietary lifestyle.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.5
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• pp.56-67
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• 2005

Rapid and reckless economical development is causing nationwide deforestation; more and more forest is being developed to be used as a base for economic advancement. While benefiting the national economy, this destruction of forest is creating a serious problem in the National Land Plan. To solve this problem, it is imperative to understand the current condition of damaged forest and make an environment-friendly plan. This paper explains the principles of spatial plan and sets the criteria for the plan, such as patch size, connectivity, and edge of the Landscape Ecology. The paper assesses the conservational value of area that are currently being developed or planned to be developed to figure out the current environmental situation. This conservational value was verified by the field survey. The result of assessment appears that the patch size of the major mountains in site is over 1,000ha and edge is located widely beside roads. The area of the high connectivity is located agriculture area in valley or narrow roads. The research shows that the patch size is related to biodiversity the larger the patch size, the more populated the species are. The research also reveals the conservational value indicated by degree of connection to forest, difference in the structure of vegetation between core area and edge area, and effects of surrounding environment. In further study, we will assess other criteria of conservation value, such as patch shape and fragmentation to the Landscape Ecology, and apply those criteria in biological aspects of the spatial plan.

• Proceedings of the Technology Innovation Conference
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• 1999.06a
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• pp.85-97
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• 1999

Being the new paradigm of "knowledge based economy", knowledge asset get to be the key to evaluate the firm's value. For a instance, Scandia firstly informed the intellectual capital report with its own financial statements in 1994. Some financial institutions have emphasized the roles of knowledge assets in the evaluating firm's value, too. But the concept of knowledge asset is so extensively defined that the result of evaluation is not as much reliable as financial statements. As previous studies examined the firm-specific cases, the sectoral pattern of knowledge asset has been ignored and it cause the difficulty in the empirical study. Moreover, the objectivity of study is ambiguous. Therefore, we regards knowledge asset as a technological knowledge asset. Which is related to R&D(research & development) and technology. Because this definition is more measurable than others and can play a frontier role in evaluating the knowledge asset. We extract the criteria related to the technological knowledge asset through the survey of 'Scandia' and other previous studies and add other criteria, which explain the Korean-specific environments. We gather data from "Technological Innovation"(STEPI, 1997, 1999) and "The bibliography of Korean R&D institutes"(KITA,1998) and "the survey of listed company"(Daewoo Securities, 1998. 1999). As the results of empirical study, the variables which explain the financial value of firms do not reflect the 'technological knowledge asset' well. It results from the factors as followings. Firstly, instead of stock price the proxy measurement related to 'knowledge asset' is needed. Secondly, the sample is biased to the large scale firms so we'll collect samples more broadly. Finally, the concept of 'technological knowledge asset' is too narrow to explain the value of firm. We expect the result of this empirical study gives contribution to the evaluation of firms' value more exactly.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.2
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• pp.82-91
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• 1989

This study was carried out to get the basic information of irrigation plans for the red pepper, such as optimum irrigation level and irrigation requirement in Taegu and Kyungpook province. In this study, red peppers were cultivated in 6 PVC pot lysimeters filled with 60cm deep clay loam soil. Four tensiometers were installed in each plot to measure the soil water pressure head. Field measurements were made during the period June 6 to October 31, 1988 at the experimental farm of Kvungpook National University. Six levels of irrigation were used. They were PF 1.8-2.0, PF 2.2-2.4, PF 2.8-3.0, FC-PF.1.7, FC-PF 2.2, and FC-PF 2.7. The results obtained from this study are summarized as follows : 1. In case of irrigation levels of narrow ranges of water contents, the higher the soil water content was, the larger the ET was. Hut in case of the irrigation levels returning to the field capacity, the lager the PF value of irrigation point was, the larger the ET was. Considering ET, yield and weight per fruit, the latter is much better than the former irrigation method. 2. The mean daily ET and mean ET ratio for each 10-day period showed that the maximum value occured in the last of August. The ranges of those were 3.74-14.64 mm/day and 0.87-3.40, respectively. These values showed that small during the early stage of growth, large during the middle stage and getting smaller in the last stage. 3. In case of irrigation levels of narrow ranges of water contents, the increase of irrigation water supplied increased the ET. The relationship between the two showed nearly straight line. Most of irrigated water was consumed as ET and the rest as percolation. But, in case of irrigation levels returning to the field capacity, the higher the PF value of irrigation point was, the larger the ET ratio was. However, their relationship didn't show straight line. 4. The irrigation level of PC - PP 2.7 was found to be the optimum irrigation level with respect to the yield, the weight per fruit, stem length, irrigation requirement and percolation quantity. In this case, mean daily ET and mean ET ratio were 6.79 mm/day (total 10052 mm) and 1.67, respectively. The maximum mean daily ET and mean ET ratio for 10-day period were 14.64 mm/day and 3.40, respectively, in the last of August, and the maximum daily ET was 2126 mm/day on August 24. 5. In case of PC - PP 2.7 which is found the optimum irrigation level, mean irrigation water required, mean ET and mean percolation water quantity were 7.44 mm/day, 6.79 mm/day(91.3% of irrigation water), and 0.38 mm/day (5.5% of it), respectively.