• Journal of Intelligence and Information Systems
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• v.25 no.3
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• pp.239-251
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• 2019

Statistical methods such as moving averages, Kalman filtering, exponential smoothing, regression analysis, and ARIMA (autoregressive integrated moving average) have been used for stock market predictions. However, these statistical methods have not produced superior performances. In recent years, machine learning techniques have been widely used in stock market predictions, including artificial neural network, SVM, and genetic algorithm. In particular, a case-based reasoning method, known as k-nearest neighbor is also widely used for stock price prediction. Case based reasoning retrieves several similar cases from previous cases when a new problem occurs, and combines the class labels of similar cases to create a classification for the new problem. However, case based reasoning has some problems. First, case based reasoning has a tendency to search for a fixed number of neighbors in the observation space and always selects the same number of neighbors rather than the best similar neighbors for the target case. So, case based reasoning may have to take into account more cases even when there are fewer cases applicable depending on the subject. Second, case based reasoning may select neighbors that are far away from the target case. Thus, case based reasoning does not guarantee an optimal pseudo-neighborhood for various target cases, and the predictability can be degraded due to a deviation from the desired similar neighbor. This paper examines how the size of learning data affects stock price predictability through k-nearest neighbor and compares the predictability of k-nearest neighbor with the random walk model according to the size of the learning data and the number of neighbors. In this study, Samsung electronics stock prices were predicted by dividing the learning dataset into two types. For the prediction of next day's closing price, we used four variables: opening value, daily high, daily low, and daily close. In the first experiment, data from January 1, 2000 to December 31, 2017 were used for the learning process. In the second experiment, data from January 1, 2015 to December 31, 2017 were used for the learning process. The test data is from January 1, 2018 to August 31, 2018 for both experiments. We compared the performance of k-NN with the random walk model using the two learning dataset. The mean absolute percentage error (MAPE) was 1.3497 for the random walk model and 1.3570 for the k-NN for the first experiment when the learning data was small. However, the mean absolute percentage error (MAPE) for the random walk model was 1.3497 and the k-NN was 1.2928 for the second experiment when the learning data was large. These results show that the prediction power when more learning data are used is higher than when less learning data are used. Also, this paper shows that k-NN generally produces a better predictive power than random walk model for larger learning datasets and does not when the learning dataset is relatively small. Future studies need to consider macroeconomic variables related to stock price forecasting including opening price, low price, high price, and closing price. Also, to produce better results, it is recommended that the k-nearest neighbor needs to find nearest neighbors using the second step filtering method considering fundamental economic variables as well as a sufficient amount of learning data.

• The Korean Journal of Archival Studies
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• no.35
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• pp.161-206
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• 2013

'Maeul' is a concept connoting a community. As a place where ordinary people's lives are planned and realized, Maeul is the foundation of their daily lives as well as a place where they work, rest and enjoy pastime activities. In Korea, however, most Maeul communities are dismantled while going though the modern period representing colonization and developmental dictatorship. Growth-oriented industrialization and urbanization turned into such adverse effects as individualization, a sense of loss and a sense of alienation. Recently, through innovations from below, Maeuls are restored, and through Maeul communities restored this way, every Maeul and many researchers carry out activities to build a healthy civil society. This study was conducted on such a background. For a healthy restoration of Maeul communities and a sustainable operation of those communities, it is necessary to establish archives where record the trace of Maeul members' daily lives and relations between those members. The archive of Maeul communities is a place that contains each Maeul's local characteristics as well as human relations as well. It is because this place can be space where Maeul members can record their history, communicate with each other and make a better future. The archive of Maeul communities can be made into various different models, which can be operated by reflecting the identity of a community such as main agents and characteristics, objectives and orientation of objects recorded. Rather than when Maeul communities exist as individuals, they can display more important functions and better effect when they form a network. Therefore, it is needed to provide various and creative methodologies different from the existing government-led record management. Not only on the form of archives, but also all over their functions, such as collection, arrangement, classification, evaluation, management and utilization, Maeul and Maeul residents' norms, orientation and realistic conditions should be thoroughly reflected. Starting from a chance to look back at individuals' lives, the archive of Maeul communities will be a new chapter to restore and build a healthy community in our society and overcome social contradictions from below. Moreover, the archive of Maeul communities has a great significance that it will broaden its prospect creatively with a new paradigm, not only mechanically turning the existing public sector-centered record management into a non-governmental sector.

• Tunnel and Underground Space
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• v.31 no.4
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• pp.289-308
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• 2021

This study conducts coupled thermo-hydro-mechanical numerical modeling to investigate the maximum temperature and conditions for securing mechanical stability of the high-level radioactive waste repository when temperature criteria of bentonite buffer are 100℃ and 125℃, respectively. In case of temperature criterion of buffer as 100℃, the maximum temperatures at the interface between canister and buffer are calculated to be 99.4℃ and 99.8℃, respectively for a case with disposal tunnel spacing of 40 m and deposition hole spacing of 5.5 m and for the other case with disposal tunnel spacing of 30 m and deposition hole spacing of 6.5 m. In case of temperature criterion of buffer as 125℃, spacings of disposal tunnel and deposition hole could be decreased to 30 m and 4.5 m, respectively, which reduces the disposal area up to 55% compared to the disposal area of KRS⁺. According to analysis of mechanical stability for various disposal spacings, RMR of rock mass for KRS⁺ should be larger than 72.4 which belongs to good rock in RMR classification to prevent failure of rock mass. As disposal spacing is decreased, required RMR of rock mass is increased. In order to prevent failure of rock mass for a case with disposal tunnel spacing of 30 m and deposition hole spacing of 4.5 m, RMR larger than 87.3 is needed. However, mechanical stability of the repository is secured for all cases with RMR over 75 considering the enhancement of rock strength due to confining stress induced by swelling of the bentonite buffer and backfill.

• Journal of the Korean earth science society
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• v.43 no.5
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• pp.591-603
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• 2022

The color and optical properties of seawater are determined by the interaction between dissolved organic and inorganic substances and plankton contained in it. The Ieodo - Ocean Research Institute (I-ORS), located in the East China Sea, is affected by the low salinity of the Yangtze River in the west and the Tsushima Warm Current in the south. Thus, it is a suitable site for analyzing the fluctuations in circulation and optical properties around the Korean Peninsula. In this study, seawater surrounding the I-ORS was classified according to its optical characteristics using the satellite remote reflectance observed with Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua and National Aeronautics and Space Administration (NASA) bio-Optical Marine Algorithm Dataset (NOMAD) from January 2016 to December 2020. Additionally, the variation characteristics of optical water types (OWTs) from different seasons were presented. A total of 59,532 satellite match-up data (d ≤ 10 km) collected from seawater surrounding the I-ORS were classified into 23 types using the spectral angle mapper. The OWTs appearing in relatively clear waters surrounding the I-ORS were observed to be greater than 50% of the total. The maximum OWTs frequency in summer and winter was opposite according to season. In particular, the OWTs corresponding to optically clear seawater were primarily present in the summer. However, the same OWTs were lower than overall 1% rate in winter. Considering the OWTs fluctuations in the East China Sea, the I-ORS is inferred to be located in the transition zone of seawater. This study contributes in understanding the optical characteristics of seawater and improving the accuracy of satellite ocean color variables.

• Journal of the Korean Chemical Society
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• v.67 no.5
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• pp.378-392
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• 2023

The purpose of this study is to analyze the pre-service chemistry teachers' cognition of the nature of model in process of designing and developing models using technology. For this purpose, 19 pre-service chemistry teachers' in the 3rd grade of a education college located in the central region observe experimental phenomena related to Boyle's law presented in the 7th grade science textbook and researchers required the design and development of a model related to the observed experimental results using technology. Based on previous studies, the nature of model were classified into two aspect: 'Representational aspect' and 'Explanatory aspect'. The 'Representational aspect' was classified into 'Representation', 'Abstraction', and 'Simplification', and the 'Explanatory aspect' was classified into 'Analysis', 'Interpretation', 'Reasoning', 'Explanation', and 'Quantification'. The pre-service chemistry teachers' cognition were analyzed by the classification. As a result of the study, the 'Representation' of the 'expressive aspect' was uniformized in the form of space that changes in volume, and the pressure was expressed as the Brightness inside the cylinder or frequency of color change of particles for 'Abstraction'. In the case of 'Simplification', the particle collision was expressed as a perfectly elastic collision, but there was a group that could not simply indicate the type of particle. In the 'Explanatory aspect', in the case of 'Analysis', volume was classified as a manipulated variable, and in the case of 'Interpretation', most groups analyzed the change in pressure through the collision of gas particles. However, the cognition involved in 'Reasoning' was not observed much. In the case of 'Explanation', there were groups that did not succeed in explanation because the area where the particles collided was not set or incorrectly set, and in the case of 'Quantification', there was a group that formulated the number of collisions per unit time, and on the contrary, there was a group that could not quantify the number of collisions because they could not be expressed in numbers.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.4
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• pp.40-48
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• 2023

This study is part of a foundational research effort aimed at developing a suitability index for breeding grounds related to avian activities along the domestic South and West coasts, including islands. Focus Group Interviews (FGI) and Analytic Hierarchy Process (AHP) analyses were conducted. The results are as follows. First, as a result of determining the value of the suitability of coastal bird breeding sites, the 'Natural Value(0.763)' was higher than the 'Artificial Value(0.237)'. Other artificial values were identified as sub-ranked except for 'Protected Areas' to ensure continuous integrity of breeding spaces. Second, as a result of re-establishing the 25 evaluation items classified in the two-time FGI as higher concepts, nine natural values and five artificial values were finally selected as a total of 14. Third, the results of the mid-classification evaluation of the importance of the suitability of coastal bird breeding sites were identified in the order of 'Ecological Value(0.392)', 'Topographic Value(0.251)', 'Passive Interference(0.124)', 'Geological Value(0.120)', and 'Active Interference(0.113)'. Fourth, the results of the priority of evaluation items of coastal bird breeding sites were in the order of 'Vegetation Distribution (0.187)', 'Area of Mudflats(0.118)', 'Presence or Absence of Mudflats(0.092)', 'Appearance of Natural Enemies(0.087)', 'Protected Areas(0.08)', 'Island Area (0.069)', 'Over-Breeding devastation(0.064)', 'Soil Composition Ratio(0.056)', 'Distance from Land(0.054)', 'Ocean farm area (0.045)', 'Cultivated land area(0.041)', 'Cultivation behavior(0.038)', 'Angle of the Surface(0.036)', and 'Land Use(0.033)'. It is judged that the weighting result value of the evaluation items derived in this study can be used for priority evaluation focusing on the coastal bird breeding area space. However, it seems that the correlation with the unique habitat suitability of bird individuals needs to be supplemented, and spatial analysis research incorporating species-specific characteristics will be left as a future task.

• The Korean Journal of Air & Space Law and Policy
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• v.28 no.2
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• pp.3-35
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• 2013

Air transport today is a means of transport that is optimized for exchanges between nations. Around the world, has experienced an increase in operating and the number of airline route expansion that has entered into the international aviation agreements in order to take advantage of the air transport efficient, but the possibility of the occurrence of air transport accidents increased. When compared to the accident of other means of transport, development of air transport accidents, not high, but it leads to catastrophe aviation accident occurs. Air Transport accident many international transportation accident than domestic transportation accident, in the event of an accident, the analysis of the legal responsibility of the shipper or the like is necessary or passenger air carrier. Judgment of the legal order of discipline of air transport accident is a classification of the type of air transport agreement. Depending on the object, air transport agreements are classified into the contract of carriage of aviation of the air passenger transportation contract. For casualties occurs, air passenger transportation accident is a need more discussion of legal discipline for this particular. Korean Commercial Code, it is possible to reflect in accordance with the actual situation of South Korea the contents of the treaty, which is utilized worldwide in international air transport, even on the system, to control land, sea, air transport and welcoming to international standards. However, Korean Commercial Code, the problem of the Montreal Convention has occurred as it is primarily reflecting the Montreal Convention. As a cause of liability for damages, under the Commercial Code of Korea and the contents of the treaty precedent is reflected, the concept of accident is necessary definition of the exact concept for damages of passengers in particular. Cause of personal injury or death of passengers, in the event of an accident to the "working for the elevation" or "aircraft" on, the Montreal Convention is the mother method of Korea Commercial Code, liability for damages of air carrier defines. The Montreal Convention such, continue to be a matter of debate so far in connection with the scope of "working for the lifting of" the concepts defined in the same way from Warsaw Convention "accident". In addition, it is discussed and put to see if you can be included mental damage passenger suffered in air transport in the "personal injury" in the damage of the passenger is in the range of damages. If the operation of aircraft, injury accident, in certain circumstances, compensation for mental damage is possible, in the same way as serious injury, mental damage caused by aviation accidents not be able to live a normal life for the victim it is damage to make. So it is necessary to interpret and what is included in the injury to the body in Korea Commercial Code and related conventions, non-economic damage of passengers, clearly demonstrated from the point of view of prevention of abuse of litigation and reasonable protection of air carrier it must compensate only psychological damage that can be. Since the compensation of delay damages, Warsaw Convention, the Montreal Convention, Korea Commercial Code, there are provisions of the liability of the air carrier due to the delayed arrival of passenger and baggage, but you do not have a reference to delayed arrival, the concept of delay arrangement is necessary. The strict interpretation of the concept of delayed arrival, because it may interfere with safe operation of the air carrier, within the time agreed to the airport of arrival that is described in the aviation contract of carriage of passenger baggage, or, these agreements I think the absence is to be defined as when it is possible to consider this situation, requests the carrier in good faith is not Indian or arrive within a reasonable time is correct. The loss of passenger, according to the international passenger Conditions of Carriage of Korean Air, in addition to the cases prescribed by law and other treaties, loss of airline contracts, resulting in passengers from a service that Korean Air and air transport in question do damage was is, that the fact that Korean Air does not bear the responsibility as a general rule, that was caused by the negligence or intentional negligence of Korean Air is proof, negligence of passengers of the damage has not been interposed bear responsibility only when it is found. It is a clause in the case of damage that is not mandated by law or treaty, and responsible only if the negligence of the airline side has been demonstrated, but of the term negligence "for" intentional or negligent "Korean Air's Terms" I considered judgment of compatibility is required, and that gross negligence is appropriate. The "Korean Air international passenger Conditions of Carriage", airlines about the damage such as electronic equipment that is included in the checked baggage of passengers does not bear the responsibility, but the loss of baggage, international to arrive or depart the U.S. it is not the case of transportation. Therefore, it is intended to discriminate unfairly passengers of international flights arriving or departure to another country passengers of international flights arriving or departure, the United States, airlines will bear the responsibility for the goods in the same way as the contents of the treaty it should be revised in the direction.

• Tuberculosis and Respiratory Diseases
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• v.43 no.6
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• pp.945-953
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• 1996

Background : Many acute and chronic lung diseases including pneumoconiosis are characterized by the presence of increased numbers of activated macrophages. These macrophages generate several inflammatory cell chemoattractants, by which neutrophil migrate from vascular compartment to the alveolar space. Recruited neutrophils secrete toxic oxygen radicals or proteolytic enzymes and induce inflammatory response. Continuing inflammatory response results in alteration of the pulmonary structure and irreversible fibrosis. Recently, a polypeptide with specific neutrophil chemotactic activity, interleukin-8(IL-8), has been cloned and isolated from a number of cells including : monocytes, macrophages and fibroblasts. IL-1 and/or TNF-${\alpha}$ preceded for the synthesis of IL-8, and we already observed high level of IL-1 and TNF-${\alpha}$ in the pneumoconioses. So we hypothesized that IL-8 may be a central role in the pathogenesis of pneumoconiosis. In order to evaluate the clinical utility of IL-8 as a biomarker in the early diagnosis of pneumoconiosis, we investigated the increase of IL-8 in the pneumoconiotic patient and the correlation between IL-8 level and progression of pneumoconiosis. Method : We measured IL-8 in the serum of 48 patients with pneumoconiosis and 16 persons without dust exposure history as a control group. Pneumoconiotic cases were divided into 3 groups according to ILO Classification : suspicious group(n=16), small opacity group(n=16) and large opacity group(n=16). IL-8 was measured by a sandwich enzytne immunoassay technique. All data were expressed as the $mean{\pm}standard$ deviation. Results: 1) The mean value of age was higher in the small opacity and large opacity group than comparison group, but smoking history was even. Duration of dust exposure was not different among 3 pneumoconiosis groups. 2) IL-8 level was $70.50{\pm}53.63pg/m{\ell}$ in the suspicious group, $107.50{\pm}45.88pg/m{\ell}$ in the small opacity group, $132.50{\pm}73.47pg/m{\ell}$ in the large opacity group and $17.85{\pm}33.85pg/m{\ell}$ in the comparison group. IL-8 concentration in all pneumoconiosis group was significant higher than that in the comparison group(p<0.001). 3) IL-8 level tended to increase with the progression of pneumoconiosis. Multiple comparison test using Anova/Scheffe analysis showed a significant difference between suspicious group and large opacity group(p<0.05). 4) The level of IL-8 was correlated with the progression of pneumoconiosis(r=0.4199, p<0.05). Conclusion : IL-8 is thought to be a good biomarker for the early diagnosis of pneumoconiosis.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.3
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• pp.25-34
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• 2020

This study examined the definition and major values, the designated procedures and types, and the designation trend in Korean scenic sites and national parks in the United States. Based on this, the analysis of the characteristics of the designation of the two natural heritages. The results are as follows; First, Scenic Sites has characteristics of complex heritage that includes academic, historical, and humanities values on the basis of landscape. As a natural heritage based on public nature, the U.S. National Park aims to contribute to the people's natural heritage and satisfy both ecological and historical values through the protection of the landscape. Second, the designation of a scenic sites are decided through deliberation by the Cultural Heritage Committee after the request of the owner, manager, or local government or by the authority of the head of the Cultural Heritage Administration. The designated survey is divided into basic resource surveys and resource surveys by type. Since the initial designation of the Sogeumgang Mountain in Cheonghakdong, Myeongju in 1970, the number of designated scenic sites was low until the 2000s, but the number of designated scenic sites has increased rapidly since 2006 due to the policy to promote the scenic site, and the proportion of natural and historical and cultural scenic sites has been balanced. The designation of the U.S. national park is decided by the Congress or the president, and the National Park Service makes a series of decisions on whether to conduct a special resource study of provisional resources through a preliminary inspection survey, whether to satisfy the criteria for designation of national parks based on the results of special resource research, and to prioritize them. The U.S. National Parks have been expanded not only by Congress but also by the president's empowerment to designate them as national monuments. With the integrated operation of the National Park Service, the number of designated cases increased as the national park included the heritage sites under the control of various ministries. In addition, a number of historical areas were designated by the enactment of the Historical Site Act, and recreational areas were designated to provide leisure space and classified and managed in a total of 18 units. Third, the comparison of the designation characteristics of the two heritage properties confirmed that the designation of natural heritage with complex value, the classification of types according to complementary designation system and resource characteristics, the establishment of the competent ministry and the balancing of the heritage according to the designation policy. The two heritages had the characteristics of complex natural heritages that met ecological, historical and academic values at the same time based on landscape and public nature. In addition, both countries have identified a system for deliberating the designation of heritage through a basic resource survey and an in-depth designation survey, and classified each type according to the characteristics of the resource. In addition, the policies for promoting scenic sites in Korea and the integrated operation of the National Park Service in the U.S. influenced the designated aspects of the two heritage sites, balancing natural heritage with historical and cultural heritage. Fourth, the resource types and conservation management methods of Scenic site and National Park were largely related. The natural areas of the U.S. National Park include types of natural monuments in Korea as major resources, and have characteristics similar to natural scenic sites. In addition, historical resources were similar to the criteria for designation of historical and cultural scenic sites in terms of landscape, and the aspects of war and celebrity-related relics were related to the types of historic sites. In terms of conservation management, the natural area of the U.S. national park has a way of keeping the original ecosystem intact, but the Korean natural heritage protection system is likely to be useful for focusing on the resource of viscosity. Meanwhile, historical resources include historical sites and historical and cultural scenic sites in the traditional era, but historical relics in the U.S. National Parks have set a time limit to modern times for war history and celebrity-related relics, and the active provision of entertainment programs based on existing resources was derived as a difference.