• Journal of Korean Port Research
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• v.9 no.2
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• pp.39-49
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• 1995

Recently, the traffic volume has been greatly increased partly because of high growth rate of domestic and world economy, and partly because of increased transhipment demand resulting from the destruction of Kobe port by earthqwake early this year. So, container facilities in Pusan Port are under serious congestion. The congestion costs in connection with container traffic in Pusan Port is estimated to be 29.3 billion won in 1994. In 1995 the situation is still worsening. PECT has continued to grow annually by 35% in cargo handling exceeding more than 31% of the total container volumes handled in Korea. The BOR of container berths in PECT in 1994 is 75% reflecting extreme congestion in container traffic. The reason for such serious congestion in PECT is the shortage of container handling facilities in comparison with ever-increasing cargo traffic. In order to solve the provisional problem, the shortage of handling capacity, a model developed to optimize the operation of PECT is described and demonstrated. The model minimizes total port costs, including the costs of dock labour, facilities and equipment, ship, containers, and cargo. The object of this study is, through the model results, mainly to determine the optimal combination of berths and cranes under various circumstances and to show that total costs per ship or unit of cargo served can be reduced by increasing the number of cranes per berth and berth utilization above present levels. Eventually, the results obtained with this model in PECT suggest that increase to 3 in the number of cranes per existing berth could reduce the need for major investments in berths and even reduce operating costs.

• Journal of Hydrogen and New Energy
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• v.34 no.2
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• pp.187-195
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• 2023

Data centers not only consume significant electricity to operate IT equipment, but also use a lot of electricity to cool the heat generated by IT equipment. The waste heat of a high-temperature polymer electrolyte fuel cell (HT-PEFC) is capable of producing cooling , so it can be effectively applied to data centers that require cooling throughout the year. The energy-saving effects of the proposed combined cooling, heat and power (CCHP) system using HT-PEFC. That was analyzed based on the annual energy consumption data of a specific data center. When the system was running at 100% of the year, It was shown that the installation of 1 MW of the proposed system can save 3,407 MWh of electrical energy per year. In addition, compared to the existing system, the annual power usage effectiveness can be improved from 2.0 to 1.57 and 6,293 MWh of extra heat energy per year can be produced to sell. Furthermore, sensitivity analysis was performed on the fuel cell operating temperature and current density to guide the appropriate installation capacity of the proposed system.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.287-292
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• 2023

The U.S. National Aeronautics and Space Administration proposed a new concept of urban air mobility in the city's short-range air transport ecosystem in order to build a new low-altitude air, and the term uam is currently used worldwide. This paradigm is also being promoted by the Korean government with the goal of commercializing urban air transport services by 2025, and furthermore, the need to secure air maneuvers and transportation capacity is emerging due to the rapidly changing future operating environment and battlefield space. In other words, this study started to present the military necessity and military operation plan by introducing the 'Agility Prime' program of the US Air Force. 'Agility Prime' program was organized in order of background and concept of urban air mobility, development trend of Korean urban air mobility and analysis of the US Air Force's 'Agility Prime' program, and it is expected that this study will be followed by a follow-up study.

• Journal of Korea Entertainment Industry Association
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• v.5 no.1
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• pp.149-153
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• 2011

In this study, a configuration method for a cloud technology based VoD system through two different scenarios is proposed. The first scenario virtualizes DMC, content storages for each SO, and stream servers in the conventional VoD system in order to efficiently use the additionally required storage capacity and stream server. In the second scenario, it is proposed that cable broadcasting systems including VoD systems are to be changed as cloud in which the subscriber STB should have minimum programs and storage regions to connect networks, and the operating system and middle ware presented in the existing subscriber STB is moved to the cloud data center. In addition, the comparison of the application of the cloud technology for the cost of changing the existing system to STB and the cost of establishing a cloud VoD system is performed in order to analyze the cost reduction in broadcasting businesses based on the establishment of VoD systems.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.4 no.4
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• pp.159-176
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• 2023

The conservation of the raccoon dog (Nyctereutes procyonoides) in South Korea requires the protection and preservation of natural habitats while additionally ensuring coexistence with human activities. Applying habitat map modeling techniques provides information regarding the distributional patterns of raccoon dogs and assists in the development of future conservation strategies. The purpose of this study is to generate potential habitat distribution maps for the raccoon dog in South Korea using geospatial technology-based models. These models include the frequency ratio (FR) as a bivariate statistical approach, the group method of data handling (GMDH) as a machine learning algorithm, and convolutional neural network (CNN) and long short-term memory (LSTM) as deep learning algorithms. Moreover, the imperialist competitive algorithm (ICA) is used to fine-tune the hyperparameters of the machine learning and deep learning models. Moreover, there are 14 habitat characteristics used for developing the models: elevation, slope, valley depth, topographic wetness index, terrain roughness index, slope height, surface area, slope length and steepness factor (LS factor), normalized difference vegetation index, normalized difference water index, distance to drainage, distance to roads, drainage density, and morphometric features. The accuracy of prediction is evaluated using the area under the receiver operating characteristic curve. The results indicate comparable performances of all models. However, the CNN demonstrates superior capacity for prediction, achieving accuracies of 76.3% and 75.7% for the training and validation processes, respectively. The maps of potential habitat distribution are generated for five different levels of potentiality: very low, low, moderate, high, and very high.

• Journal of Korean Society of Rural Planning
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• v.30 no.1
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• pp.67-79
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• 2024

The Comprehensive Rural Village Development Project, a resident-led bottom-up regional development project, began in 2004. This study investigated difficulties and problems in the operation process after the completion of the project, and future improvement plans, through in-depth interviews with the former and current chairman of the steering committee, steering committee members, and office managers, targeting three regions in Jeollanam-do, 15 years after the completion of the project. As a result of the survey and analysis, it was effective in improving the living environment and characteristics of each village and revitalizing the area. And while there were well-run facilities depending on the type of project, there were also many idle facilities. In the case of communal facilities, there was a high possibility of problems in operation and management when the scale of the new building was large. Conflicts occurred between villages in the process of independently operating the area after the completion of the project. Therefore, it is necessary to provide an S/W project program to prepare for after completion. Local governments need to utilize City and County Capacity Enhancement Projects to support regional leaders to participate in educational programs after completion and provide guidance and supervision for village operations.

• Imaging Science in Dentistry
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• v.54 no.2
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• pp.171-180
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• 2024

Purpose: This study was conducted to identify the typical sites and patterns of peri-implant bone defects on cone-beam computed tomography (CBCT) images, as well as to evaluate the detectability of the identified bone defects on panoramic images. Materials and Methods: The study population included 114 patients with a total of 367 implant fixtures. CBCT images were used to assess the presence or absence of bone defects around each implant fixture at the mesial, distal, buccal, and lingual sites. Based on the number of defect sites, the presentations of the peri-implant bone defects were categorized into 3 patterns: 1 site, 2 or 3 sites, and circumferential bone defects. Two observers independently evaluated the presence or absence of bone defects on panoramic images. The bone defect detection rate on these images was evaluated using receiver operating characteristic analysis. Results: Of the 367 implants studied, 167 (45.5%) had at least 1 site with a confirmed bone defect. The most common type of defect was circumferential, affecting 107 of the 167 implants(64.1%). Implants were most frequently placed in the mandibular molar region. The prevalence of bone defects was greatest in the maxillary premolar and mandibular molar regions. The highest kappa value was associated with the mandibular premolar region. Conclusion: The typical bone defect pattern observed was a circumferential defect surrounding the implant. The detection rate was generally higher in the molar region than in the anterior region. However, the capacity to detect partial bone defects using panoramic imaging was determined to be poor.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.7-24
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• 1977

This paper is the forth and fifth one of the study on balanced type oscillating mole drainer. In the light of the results from previous reports about the model tests, some design criteria were established and a prototype machine was set up for experimental purpose. Motion characteristics and functionof the each parts of the machine were checked and analyzed. After that, performance tests of the prototype machine were carried out in thefield. Obtained results are summarized as follows ; 1. Ten centimeter of the bullet diameter was determined so as to be able to attach it to the tractors with capacity of 30 PS to 40 PS. 2. To maintain the balance between the moments of the front shank and rear shank, the oscillating amplitude of the rear bullet was determined to be larger than that of the front bullet. At the same time , the oscillating direction of the rear bullet was designed with the inclines of ten to thirty degrees. 3. An octagonal dynamo transduced was developed for measuring the compressive force of the upper link is measuring the draft force of the machine. Acceptable linear relationship between forces and strain responses from O.D.T. was obtained. 4. Analysing the balancing mechanism of the acting part of the machine , it was found that the total draft force of the machine was equal to the difference between the sum of the draft force produced from the right and left side bending moments of the lower drawber and the compressive force on the upper link. 5. There are acceptable linear relationship between the strain and twisting moment by driving shaft, and between strain and shank moment. Above results enable us to carry out the field experiment with prototype machine. 6. When the test machine was used in the field, it was possible to reduce the oscillating acceleration by forty percent in average as compared it with the single bullet mole drainer. 7. When the test machine was used under the oscillating condition, the dratt torce was reduced by 27 percent to 59 percent as compared it with the test machine under non-oscillating condition, while the draft force was increased by 7 percent to 20 percent as compared it with the mole drainer having oscillating single bullet. The reasoning behind this fact was considered as the resistance force due to the rear shank and bullet. 8. As the amplitude and frequency of the bullet were increased, the torque was increased accordingly. This tendency could be varied with the various characteristics of the given soils. And the larger frequency and amplitute, the more increasing oscil\ulcornerlating power but decreasing draft brce were needed, and draft force was increased as the velocity was increased.9. When the amplitude of the rear bullet was designed to be larger than that of the front bullet, the minimum value of the moment was lowered and oscillating acceleration was reduced. And when the oscillating direction of the rear bullet was declined back\ulcornerwards, oscillating acceleration was increased along with the increasing angle of decli\ulcornernation. When the test machine was operated in high speed, the difference between maximum moments and minimum ones became narrow. This varying magnitude of moments appeared on the moment oscillogram seems to be correlated to the oscillating acceleration and draft force. 10. From the analysis of variance, it was found that those factors such as frequency, amplitude, and operating velocity significantly affected in the oscillating acceleration, the draft resistance, the torque, the moment, and the total power required. And interaction between frequency and amplitude affected in the oscillating acceleration. 11. Within the given situation of this study, the most preferable operating conditions of the test machine were 7 Hz in oscillating frequency, 0.54 m/sec in operating velocity, and 39.1 mm in oscillating amplitude of front and rear bullets. However, it is necessary to select the proper frequency and magnitude of oscillation depending on the soil properties of the field in which the mole drainer is practiced by use of a bal1nced type oscillating mole drainer. 12. It is recommended that a comparative study of the mole drainers would be performed in the near future using two separate balanced oscillating bullet with the one which is operated by oscillating the movable bullet in a single cylinder or other balanced type which may be single oscillating bullet with spring, damper or balancing weight, and that of thing. To expand the applicability of the balanced type oscillating mole drainer in practical use, it is suggested to develop a new mechanism which perform mole drain with vinyl pipe or filling material such as rice hull.

• Journal of Intelligence and Information Systems
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• v.24 no.3
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• pp.157-176
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• 2018

The purpose of this research is to develop a detection model for companies designated as administrative issue in KOSDAQ market using financial data. Administration issue designates the companies with high potential for delisting, which gives them time to overcome the reasons for the delisting under certain restrictions of the Korean stock market. It acts as an alarm to inform investors and market participants of which companies are likely to be delisted and warns them to make safe investments. Despite this importance, there are relatively few studies on administration issues prediction model in comparison with the lots of studies on bankruptcy prediction model. Therefore, this study develops and verifies the detection model of the companies designated as administrative issue using financial data of KOSDAQ companies. In this study, logistic regression and decision tree are proposed as the data mining models for detecting administrative issues. According to the results of the analysis, the logistic regression model predicted the companies designated as administrative issue using three variables - ROE(Earnings before tax), Cash flows/Shareholder's equity, and Asset turnover ratio, and its overall accuracy was 86% for the validation dataset. The decision tree (Classification and Regression Trees, CART) model applied the classification rules using Cash flows/Total assets and ROA(Net income), and the overall accuracy reached 87%. Implications of the financial indictors selected in our logistic regression and decision tree models are as follows. First, ROE(Earnings before tax) in the logistic detection model shows the profit and loss of the business segment that will continue without including the revenue and expenses of the discontinued business. Therefore, the weakening of the variable means that the competitiveness of the core business is weakened. If a large part of the profits is generated from one-off profit, it is very likely that the deterioration of business management is further intensified. As the ROE of a KOSDAQ company decreases significantly, it is highly likely that the company can be delisted. Second, cash flows to shareholder's equity represents that the firm's ability to generate cash flow under the condition that the financial condition of the subsidiary company is excluded. In other words, the weakening of the management capacity of the parent company, excluding the subsidiary's competence, can be a main reason for the increase of the possibility of administrative issue designation. Third, low asset turnover ratio means that current assets and non-current assets are ineffectively used by corporation, or that asset investment by corporation is excessive. If the asset turnover ratio of a KOSDAQ-listed company decreases, it is necessary to examine in detail corporate activities from various perspectives such as weakening sales or increasing or decreasing inventories of company. Cash flow / total assets, a variable selected by the decision tree detection model, is a key indicator of the company's cash condition and its ability to generate cash from operating activities. Cash flow indicates whether a firm can perform its main activities(maintaining its operating ability, repaying debts, paying dividends and making new investments) without relying on external financial resources. Therefore, if the index of the variable is negative(-), it indicates the possibility that a company has serious problems in business activities. If the cash flow from operating activities of a specific company is smaller than the net profit, it means that the net profit has not been cashed, indicating that there is a serious problem in managing the trade receivables and inventory assets of the company. Therefore, it can be understood that as the cash flows / total assets decrease, the probability of administrative issue designation and the probability of delisting are increased. In summary, the logistic regression-based detection model in this study was found to be affected by the company's financial activities including ROE(Earnings before tax). However, decision tree-based detection model predicts the designation based on the cash flows of the company.

• Journal of Mushroom
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• v.2 no.2
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• pp.76-87
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• 2004

This experiments were conducted to study on the economic analysis of Phellinus spp.(Comercial name: Sanghwang mushroom). These results were as follows: Phellinus spp. can be cultivated about 4 years by one time inoculation. This mushroom has been cultivated by the method of burying log into the soil(BM) at the first time. Recently, however, the method of hanging log on the shelves in the house(HM) is used, because HM has more advantage than BM that HM can be cultivated more pieces of logs than BM. On the other hand, HM is required to invest more 5,678,230Won for the equipments than the BM. And also, HM is required 14,400 pieces(2.8 times) more log numbers than BM 5,000 pieces. Also, HM is required more 3,680,000Won to purchase log, 1,104,000Won to purchase spawn. The cost of production is required to 20,180,971Won for BM, and 37,953,825Won for HM. Accordingly, product cost of HM is 1.9 times higher than BM. The operating cost is required to 1,207,712Won for BM, and 24,075,432Won for HM. Accordingly, operating cost of HM is 2.0 times higher than BM. The net income is 580,940,000Won for BM, and 1,683,300,000Won for HM. Accordingly, net income of HM is 2.9 times higher than BM. The income is 589,040,000Won for BM, and 169,718,000Won for HM. Accordingly, income of HM is 2.9 times higher than BM. In conclusion, HM is required 2.8 times more logs. HM has 1.03 times more products per a piece of log. HM has 1.9 times more production cost, and 2.0 times more operating cost. As you read above, HM and BM have two different aspects. BM is required less investment cost than HM, but BM has lower income because of the different capacity of production. By the comparing those two methods, HM is resulted more efficient method for the producing mushroom. Only in the side of cash flowing, the cash expenditure of BM is required less money at first year. But it has no production at first year. BM would get the income after 2 years buring the logs. The cash expenditure of HM is required much money for the equipments and the logs at first year, but HM would get the income at first year.