• IE interfaces
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• v.24 no.4
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• pp.304-313
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• 2011

An Unmanned Aerial Vehicle(UAV) is a powered pilotless aircraft, which is controlled remotely or autonomously. UAVs are currently employed in many military missions(surveillance, reconnaissance, communication relay, targeting, strike etc.) and a number of civilian applications(communication service, broadcast service, traffic control support, monitoring, measurement etc.). For accomplishing the UAV's missions, guarantee of survivability should be preceded. The main objective of this study is the path planning to maximize survivability for UAV based on 3-dimensional environment. A mathematical programming model is suggested by using MRPP(Most Reliable Path Problem) and solved by transforming MRPP into SPP(Shortest Path Problem). This study also suggests a $A^*PS$ algorithm based on 3-dimensional environment to UAV's path planning. According to comparison result of the suggested algorithm and SPP algorithms (Dijkstra, $A^*$ algorithm), the suggested algorithm gives better solution than SPP algorithms.

• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.103-113
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• 2011

This research is to select a path planning algorithm to maximize survivability for Unmanned Aerial Vehicle(UAV). An UAV is a powered pilotless aircraft, which is controlled remotely or autonomously. UAVs are currently employed in many military missions(surveillance, reconnaissance, communication relay, targeting, strike etc.) and a number of civilian applications(communication service, broadcast service, traffic control support, monitoring, measurement etc.). In this research, a mathematical programming model is suggested by using MRPP(Most Reliable Path Problem) and verified by using ILOG CPLEX. A path planning algorithm for UAV is selected by comparing of SPP(Shortest Path Problem) algorithms which transfer MRPP into SPP.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.240-245
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• 2011

Vegetation changes were studied for 16 yr in clearcut logged Pinus densiflora forests in the southern Gangwon-do province in Korea by applying chronosequence approach. Ambient temperature and relative humidity, Detrended Correspondence Analysis (DCA), Multiple Responses Permutation Procedure (MRPP), Indicator Species Analysis (ISPAN) were used to examine successional trajectory and compositional changes. After clearcutting, canopy openness was increased abruptly at three folds (1yr 68.3% and R1 23.0%) and then decreased, but relative moisture was slightly decreased (6%) compare to control site. In the result of DCA, right after clear cutting, vegetation composition was developed heterogeneously compared to control sites, and then approached to control sites within 16 years. Based on MRPP, species composition of each developmental stages (1yr, 3yr, 10yr and 16yr) revealed signigicant differences to that of control vegetation (R1, R3, R10 and R16). Indicator species in 1yr and 3yr samples included various woody species rather than herbaceous species, but in 10yr and 16yr, herbaceous were more abundant. Earlier succession of pine forests likely can explain to Initial Floristic Composition (IFC) Model.

• IE interfaces
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• v.25 no.3
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• pp.365-375
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• 2012

An Unmanned Aerial Vehicle (UAV) is a powered pilotless aircraft, which is controlled remotely or autonomously. UAVs are an attractive alternative for many scientific and military organizations. UAVs can perform operations that are considered to be risky or uninhabitable for humans. UAVs are currently employed in many military missions and a number of civilian applications. For accomplishing the UAV's missions, guarantee of survivability should be preceded. The main objective of this study is to suggest a mathematical programming model and a $A^*PS$_PGA (A-star with Post Smoothing_Parallel Genetic Algorithm) for Multiple UAVs's path planning to maximize survivability. A mathematical programming model is composed by using MRPP (Most Reliable Path Problem) and MTSP (Multiple Traveling Salesman Problem). After transforming MRPP into Shortest Path Problem (SPP),$A^*PS$_PGA applies a path planning for multiple UAVs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.3
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• pp.24-34
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• 2011

An Unmanned Aerial Vehicle (UAV) is a powered pilotless aircraft, which is controlled remotely or autonomously. UAVs are an attractive alternative for many scientific and military organizations. UAVs can perform operations that are considered to be risky or uninhabitable for human. UA V s are currently employed in many military missions such as reconnaissance, surveillance, enemy radar jamming, decoying, suppression of enemy air defense (SEAD), fixed and moving target attack, and air-to-air combat. UAVs also are employed in a number of civilian applications such as monitoring ozone depletion, inclement weather, traffic congestion, and taking images of dangerous territory. For accomplishing the UAV's missions, guarantee of survivability should be preceded. The main objective of this study is to suggest a mathematical programming model and a $A^*PS$-PGA (A-star with Post Smoothing-Parallel Genetic Algorithm) for an UAV's path planning to maximize survivability. A mathematical programming model is composed by using MRPP (Most Reliable Path Problem) and TSP (Traveling Salesman Problem). A path planning algorithm for UAV is applied by transforming MRPP into SPP (Shortest Path Problem).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.5
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• pp.59-76
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• 2022

This study was conducted to investigated woody species community classification and understory vegetation characteristics of Abies nephrolepis forest in Mt. Gyebang and Mt. Odae designated as Protected Area for Forest Genetic Resource Conservation and National Park. Vascular plants were surveyed as following; 55 family, 148 species, 3 sub species, 14 variety, 2 form 167 taxa. As an analysis of the species estimator of Jackknife 1, 29 survey plots could be representative of vegetation in study site. Results of the woody species, 3 communities were divided by cluster analysis(A=Abies nephrolepis-Tilia amurensis, B=Betula ermanii-Abies nephrolepis, C=Quercus mongolica-Abies nephrolepis). Using MRPP-test, there were significant differences between the communities indicating analysis of the appropriate group classification(p<0.01). The basal area and altitude were analyzed by negative relationship for NMS ordination. By analyzing plexus diagram of woody species, Acer pseudosieboldianum is strong associated with Quercus mongolica and Rhododendron schlippenbachii. Magnolia sieboldii is strong associated with Acer pictum subsp. mono etc.

• Journal of Korean Society of Forest Science
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• v.103 no.2
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• pp.165-174
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• 2014

This study was conducted to investigate composition of understory vegetation and indicator species by altitude and slope azimuth in Mt. Gyebang designated as Protected Area for Forest Genetic Resource Conservation and National Park. Tracheophytes were 350 taxa; 80 families, 203 genera, 303 species, 38 varieties, 5 forma and 4 sub-species in research area. The species of greatest importance value were Tripterygium regelii (9.143%), Acer pseudosieboldianum (7.594%), Symplocos chinensis for. pilosa (6.347%) in the shrub layer and were Sasa borealis (8.653%), Isodon excisus (2.936%) and Carex siderosticta (2.897%). In the herb layer as a result of NMS analysis, the distribution range of the major species were found to be affected by the altitude (shrub layer: $R^2$ > 0.3, herb layer: $R^2$ > 0.6). The result of plexus diagram analysis showed that Acer pseudosieboldianum was associated with Magnolia sieboldii, Acer barbinerve, Euonymus oxyphyllus etc. in the shrub layer; Meehania urticifolia was associated with Aconitum jaluense, Veratrum oxysepalum, Prunus padus etc. in the herb layer. The significant indicator species were analyzed for 60 species by the altitude and investigated for 30 species in accordance with the slope azimuth. As a consequence of MRPP, interspecies composition along the altitude group was heterogeneous and the species composition according to the azimuth slope was extremely different between the NE and SW.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.1-11
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• 2014

This study was conducted to investigate the changes understory vegetation composition (shrub and herb layers) in Mt. Gyebang as a northern-temperate deciduous broadleaf forest. Tracheophytes were 146 taxa, consisting 56 families, 93 genera, 124 species, 17 varieties, 3 forma, 2 sub-species and 1 unknown taxa in research subject area. As species area curve analysis, herbaceous layer and shrub species have been decreased over time. As a result of Mantel-test, basal area of upper layer affects to understory vegetation change (p<0.0001). Mean importance value was dominated Lindera obtusiloba (21.585%), Rhododendron schlippenbachii (19.774%) in the shrub layer, identified Sasa borealis (14.082%) and Lindera obtusiloba (7.921%) in the herb layer. According to NMS analysis of shrub layer, Species characterized by strong correlation have been reduced as time goes by. And it reports different species as an increasing in basal area of the upper layer. Herb layer plots of the NMS analysis, Rhododendron schlippenbachii and Rhododendron mucronulatum consistently were affected in shrub layer. In consequence of MRPP-test for changes in vegetation composition, It was analyzed that there are no significant differences for vegetation composition changes on shrub layer in 5-10 years. As a changes of vegetation composition on herb layer were analyzed significantly, composition change of herb layer species was larger than shrub layer species in understory vegetation.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.405-416
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• 2023

In this study, the sustainability of Abies nephrolepis in the presence of Tripterygium regelii was analyzed. To accomplish this, a field survey of140 stands was conducted. Based on the presence or absence of T. regelii, as well as the layer in which it was present (where appropriate), the type of T. regelii presence wasclassified as follows: TP type, indicating the presence of T. regelii in the tree and sub-tree layers; SP type, indicating its presence in the shrub layer; and A type, indicatingits absence from all layers. The indicator species analysis revealed T. regelii to be an indicator species of the TP type and SP type. The MRPP test was used to examine the differences among the types. Moreover, the seedling and DBH class analysis indicated there to be a difficulty in terms of the status competition, as the number of young trees generated by A. nephrolepis was the lowest in the TP type. The findings of this study enhanced our understanding of the vegetation structure of A. nephrolepis, thereby contributing to efforts concerningits conservation and management.

• Journal of Environmental Impact Assessment
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• v.31 no.6
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• pp.388-408
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• 2022

This study was conducted to select the indicator species (plant) according to the topographical characteristics in the Picea jezoensis forests, endangered subalpine coniferous trees. In South Korea and China (close to Baekdusan), the southern tree line limit of Picea jezoensis has meaningful geographical and latitudinal values for analyzing the ecological characteristics of P. jezoensis forests. Latitude greatly affects the geographical values of plant ecology, and the difference in latitude and habitat affects the change in species composition in forests. With prolonged environmental change, the habitat of subalpine plants will become smaller, and the plants may become extinct. As the P. jezoensis forests of South Korea and China, in particular, are in danger of disappearing without protection, it is important to monitor the population and develop a conservation strategy. Eighty-seven circular plots were established in P. jezoensis forests in South Korea and China. Through processes such as MRPP-test and NMS ordination, indicator species were selected based on this, and basic data for biodiversity assessment were presented. As a result of the Indicator Species Analysis (ISA), 5 taxa were selected from the upperstory vegetation and 18 taxa from the understory vegetation at the altitude(p<0.05). Indicator species by aspect were analyzed as 3 taxa for upperstory vegetation and 16 taxa for understory vegetation (p<0.05). In the case of indicator species according to the slope, 6 taxa for upper vegetation and 24 taxa for understory vegetation were selected(p<0.05). As for the indicator species according to their habitat, 8 taxa in upper vegetation and 65 taxa on understory vegetation were selected. As a result of MRPP-test, it was analyzed that the species composition was heterogeneous in the group of understory vegetation than that of upperstory vegetation. As a result of NMS ordination, the correlation with environmental factors of indicator species was analyzed by rock exposure for upperstory vegetation and latitude for understory vegetation (cut off level=0.3).