• Journal of The Geomorphological Association of Korea
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• v.18 no.2
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• pp.65-80
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• 2011

This is to find out geomorphological environment of optimum location for the object of dwelling site of Bronze Age (hereinafter called dwelling site) of total 177 unit confirmed in Yongducheon basin and Onyangcheon basin (hereinafter called investigation-object basin) in Asan-si Chungnam. To do this, hill of investigation-object basin where dwelling sites were confirmed was divided into 11 units of hillslope geomorphological and this was combined with the grade of 5 units of gradient and again subdivided into total 55 units of micro-landforms of Hillslope. Based on this, in the viewpoint of 'gradient of each of micro-landforms' analyzed 'number of dwelling sites' and 'dwelling site distribution density (unit: number of dwelling sites/1000m2)'. As the result, the optimum geomorphological environment where dwelling sites were located was largely confirmed be 5 units(① semi-gentle slope land of crest slope ②gentle slope land of crest slope ③ slope of upper sideslope ④ flat land of crest slope ⑤ flat land of crest flat). It is thought that this analysis data will be used in the future as basic data for the study of predicting distribution of dwelling sites in Bronze Age which might have been buried in the investigation-object basin.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.5
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• pp.1-15
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• 2020

This study was designed to come up with a way of managing a cultural landscape forest by conducting research on the vegetation structure and growth characteristics. This study's target site, which was 45,201㎡ in size, was Pinus densiflora forest for Sugumagi placed at the entrance of Unmun Temple, Sinwon-ri, Unmun-myeon, and Cheongdo-gun in the southernmost part of Gyeongsangbuk-do, Korea. Sugumagi means the water of the valley flows far away, and where no downstream is visible according to feng shui. The historical sources of the Sugumagi Pinus densiflora forest at the entrance of Unmun Temple isn't clear. It waw only found at that location. The Pinus densiflora forest at the entrance of Unmun Temple is located in the waterway in terms of Feng Shui. The present condition of growth was investigated through a grid surveys of 98 trees and Pinus densiflora growth. As a result of the analysis of growth status, Pinus densiflora, Larix leptolepis, Zelkova serrata, Celtis sinensis, and Rhus javanica were distributed in the conopy layer, and 28 species including Ailanthus altissima were grown in the understroy layer, and 92 species, including Ampelopsis brevipedunculata, in the shrub layer. The plant community structure was divided into low, medium and high-density Pinus densiflora forests in the study area, based on the number in the conopy layer and the grade of and the trees analyzed. As a result of the analysis, the Pinus densiflora dominated the low, medium and high-density Pinus densiflora forests, and there were no competitive species. The relative dominance of the low-density Pinus densiflora forests was 46.9% on average, medium-density was 62.6% and 50.2% was found in high-density. The mean species diversity of Shannon in the low-density study was 0.7055, medium-density study was 0.8966 and the average species diversity of Shannon in the high-density study was 0.8317. The analysis of the age and growth of 25 sample trees in the Sugumagi Pinus densiflora forest shows that the distribution of the chest diameter (DBH) of the sample Pinus densiflora is 38 to 77cm with the average chest diameter being 61.1cm. The age was 84-161 years and the average was 114 years. In the Pinus densiflora forest, most(670,659, or 98.3%) of the tree trunk wound was collected for rosins during the Japanese colonia Era, Of the total 670, 659 were Pinus densiflora, 98.3% of the total. 394 were surgically repaired in 2005. For the preservation of the Sugumagi Pinus densiflora forest, dead trees should be replaced with substitute trees appropriate to the middle and south topography. It is demanded that foreign species such as Larix leptolepis in the research area should be removed and Pinus densiflora that underwent surgical operations should be regularly sterilized. It is also emphasized that the management of insecticide is important.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.1
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• pp.1-28
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• 2019

This study analyzed the density and mortality rate of Korean fir at 9 sites where individuals of Korean firs were marked into the live and dead trees with coordinates on orthorectified aerial images by digital photogrammetric system. As a result of the analysis, Korean fir in each site showed considerable heterogeneity in density and mortality rate depending on the location within site. This make it possible to assume that death of Korean fir can occur by specific factors that vary depending on the location. Based on the analyzed densities and mortality rates of Korea fir, we investigated the correlation between topographic factors such as altitude, terrain slope, drainage network, solar radiation, aspect and the death of Korean fir. The density of Korean fir increases with altitude, and the mortality rate also increases. A negative correlation is found between the terrain slope and the mortality rate, and the mortality rate is higher in the gentle slope where the drainage network is less developed. In addition, it is recognized that depending on the aspect, the mortality rate varies greatly, and the mean solar radiation is higher in live Korean fir-dominant area than in dead Korean fir-dominant area. Overall, the mortality rate of Korean fir in Mt. Halla area is relatively higher in areas with relatively low terrain slope and low solar radiation. Considering the results of previous studies that the terrain slope has a strong negative correlation with soil moisture and the relationship between solar radiation and evaporation, these results lead us to infer that excess soil moisture is the cause of Korean fir mortality. These inferences are supported by a series of climate change phenomena such as precipitation increase, evaporation decrease, and reduced sunshine duration in the Korean peninsula including Jeju Island, increase in mortality rate along with increased precipitation according to the elevation of Mt. Halla and the vegetation change in the mountain. It is expected that the spatial patterns in the density and mortality rate of Korean fir, which are controlled by topography such as altitude, slope, aspect, solar radiation, drainage network, can be used as spatial variables in future numerical modeling studies on the death or decline of Korean fir. In addition, the method of forest distribution survey using the orthorectified aerial images can be widely used as a numerical monitoring technique in long - term vegetation change research.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.287-292
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• 2012

In this study, Multi-Channel Magnetic Flux Leakage(MFL) sensor - based inspection system was applied to monitor the condition of cables. This inspection system measures magnetic flux to detect the local faults(LF) of steel cable. To verify the feasibility of the proposed damage detection technique, an 8-channel MFL sensor head prototype was designed and fabricated. A steel cable bunch specimen with several types of damage was fabricated and scanned by the MFL sensor head to measure the magnetic flux density of the specimen. To interpret the condition of the steel cable, magnetic flux signals were used to determine the locations of the flaws and the level of damage. Measured signals from the damaged specimen were compared with thresholds set for objective decision making. In addition, the magnetic flux density values measured from every channel were summed to focus on the detection of axial location. And, sum of flux density were displayed with threshold. Finally, the results were compared with information on actual inflicted damages to confirm the accuracy and effectiveness of the proposed cable monitoring method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1638-1654
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• 2018

The heterogeneous network (HetNet) has been one of the key technologies in Long Term Evolution-Advanced (LTE-A) with growing capacity and coverage demands. However, the introduction of femtocells has brought serious co-layer interference and cross-layer interference, which has been a major factor affecting system throughput. It is generally acknowledged that the resource allocation has significant impact on suppressing interference and improving the system performance. In this paper, we propose a hybrid-clustering algorithm based on the $Mat{\acute{e}}rn$ hard-core process (MHP) to restrain two kinds of co-channel interference in the HetNet. As the impracticality of the hexagonal grid model and the homogeneous Poisson point process model whose points distribute completely randomly to establish the system model. The HetNet model based on the MHP is adopted to satisfy the negative correlation distribution of base stations in this paper. Base on the system model, the spectrum sharing problem with restricted spectrum resources is further analyzed. On the basis of location information and the interference relation of base stations, a hybrid clustering method, which takes into accounts the fairness of two types of base stations is firstly proposed. Then, auction mechanism is discussed to achieve the spectrum sharing inside each cluster, avoiding the spectrum resource waste. Through combining the clustering theory and auction mechanism, the proposed novel algorithm can be applied to restrain the cross-layer interference and co-layer interference of HetNet, which has a high density of base stations. Simulation results show that spectral efficiency and system throughput increase to a certain degree.

• Journal of Mechanical Science and Technology
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• v.14 no.3
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• pp.320-330
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• 2000

It is desirable to perform nondestructive evaluation (NDE) to assess material properties and part homogeneity because the manufacturing of carbon/carbon brake disks requires complicated and costly processes. In this work several ultrasonic techniques were applied to carbon/carbon brake disks (322mm ad, 135mm id) for the evaluation of spatial variations in material properties that are attributable to the manufacturing process. In a large carbon/carbon disk manufactured by chemical vapor infiltration (CYI) method, the spatial variation of ultrasonic velocity was measured and found to be consistent with the densification behavior in CYI process. Low frequency (e.g., 1-5MHz) through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity. Images based on both the amplitude and the time-of-flight of the transmitted ultrasonic pulse showed significant variation in the radial direction. The radial variations in ultrasonic velocity and attenuation were attributed to a density variation caused by the more efficient densification of pitch impregnation near the id and od and by the less efficient densification away from the exposed edged of the disk. Ultrasonic velocities in the edges of the disk. Ultrasonic velocities in the thickness direction were also measured as a function of location using dry-coupling transducers ; the results were consistent with the densification behavior. However, velocities in the in-plane directions (circumferential and radial) seemed to be affected more by the relative contents of fabric and chopped fiber, and less by the void content.

• Journal of environmental and Sanitary engineering
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• v.13 no.3
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• pp.79-84
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• 1998

The study result on the domestic waste occurrence and admistration condition of Iksan City as follows ; 1. The year of 1995 has observed a radically decreasing ratio of per capita waste generation compared to the previous year by 26.2%, owing to the publication of the new amendment of volume based charge as well as to the rural population included through the merger of Iksan City and Iksan Country ; the daily quantity of domestic waste for Iksan residents in 1997 was calculated to be $0.66kg/capita{\cdot}day$. 2. Waste generation in nonresidential areas were $8.04kg/capita{\cdot}day$ in average ; the quantity per capita in market places was observed to generate the largest, $36.76kg/capita{\cdot}day$, while that of services was the smallest $0.25kg/capita{\cdot}day$. 3. The average generation per capita of household waste was $0.23kg/capita{\cdot}day$ in the area which has no volume based charge system. This area showed no difference from those of other areas ; the apparent density of the waste recorded the lowest $0.llkg/{\ell}$ for District Offices, while the highest among the classified fields was $0.40kg/{\ell}$ of the Fire Station. 4. Iksan City showed great contribution by decreasing the absolute quantity of waste for landfill by waste classfication, according to the days of the week and reutilizing recyclable waste since August, 1997. 5. Location of a landfill site for disposal of nonrecyclable waste will cause a serious problem to the community and it will be highly recommendable to have governmental support and professtional consultation as well as open discussions, such as hearings, for the settlement of the problem.

• Journal of Intelligence and Information Systems
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• v.13 no.4
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• pp.45-63
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• 2007

Recently as ubiquitous environment comes to the fore, information density is raised and enterprise is being able to capture and utilize customer-related information at the same time when the customer purchases a product. In this environment, a need for the recommender systems which can deliver proper information to the customer at the right time and right situation is highly increased. Therefore, the research on recommender systems continued actively in a variety of fields. Until now, most of recommender systems deal with item recommendation. However, in the market in ubiquitous environment where the same item can be purchased at several stores, it is highly desirable to recommend store to the customer based on his/her contextual situation and preference such as store location, store atmosphere, product quality and price, etc. In this line of research, we proposed the store recommender system using customer's contextual situation and preference in the market in ubiquitous environment. This system is based on collaborative filtering and Apriori algorithms. It will be able to provide customer-centric service to the customer, enhance shopping experiences and contribute in revitalizing market in the long term.

• Journal of Industrial Convergence
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• v.21 no.1
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• pp.175-185
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• 2023

Recently, novel viral infections such as COVID-19 have spread and pose a serious public health problem. In particular, these diseases have a fatal effect on the elderly, threatening life and causing serious social and economic losses. Accordingly, applications such as telemedicine, healthcare, and disease prevention using the Internet of Things (IoT) and artificial intelligence (AI) have been introduced in many industries to improve disease detection, monitoring, and quarantine performance. However, since existing technologies are not applied quickly and comprehensively to the sudden emergence of infectious diseases, they have not been able to prevent large-scale infection and the nationwide spread of infectious diseases in society. Therefore, in this paper, we try to predict the spread of infection by collecting various infection information with regional limitations through a virus disease information collector and performing AI analysis and severity matching through an AI broker. Finally, through the Korea Centers for Disease Control and Prevention, danger alerts are issued to the elderly, messages are sent to block the spread, and information on evacuation from infected areas is quickly provided. A realistic elderly support system compares the location information of the elderly with the information of the infected area and provides an intuitive danger area (infected area) avoidance function with an augmented reality-based smartphone application. When the elderly visit an infected area is confirmed, quarantine management services are provided automatically. In the future, the proposed system can be used as a method of preventing a crushing accident due to sudden crowd concentration in advance by identifying the location-based user density.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.723-734
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• 2008

In this paper, the problems and betterment plan in operating district units plan are studied by selecting typal case locations based on the types of district units plan of the city of Busan. According to the types, 4 locations of 'type of maintaining preexisting district' and 3 of 'type of managing preexisting district' are selected as case locations, based on a scale and characteristics of each location.In systematical aspects of the case locations, indiscreet upward adjustment of the locations, insignificant participation of the citizens and patternization were recognized as problems. And setting accurate standards for target and range of alteration in line with usage plan of the locations would be necessarily urgent. So through the analysing process of the problems arisen from the case locations I would suggests necessary solutions to improve the effectiveness of the district units plan. And In planning aspects, the similarity between the basic directions and the object, batch-application of the density plan, inadequacy of the usage plan, allocations and patterns of structures, and color planning were recognized to have problematic points. Consequently distinguished specific operating-guidelines would be necessary to achieve the basic directions and the object of district units plan. Furthermore, the building-to-land ratio and floor space index are needed to be exactly calculated through providing accurate and logical standards for appropriate development density of structures.