• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2005.03a
• /
• pp.68-73
• /
• 2005

In succession of the previous works, seismo-acoustic analysis was conducted to collect ground truth events and to discriminate surface explosions from natural earthquakes in the Korean Peninsula for 2004. In this period, total 510 seismo-acoustic events corresponding to 10.8 percent of total seismic events occurred in and near the Korean Peninsula were analyzed and discriminated as artificial surface explosions. Events distribution of the seismo-acoustic events in 2004 is similar to the previous results of 1999-2003. And newly determined seismo-acoustic events were added to the surface explosions database. To extend infrasound detection capability, Korea Institute of Geoscience and Mineral Resources (KIGAM) and Southern Methodist University (SMU) installed new seismo-acoustic array (BRDAR) in Baekryoung Island last November, 2004. The array configuration and design is nearly same to previous seismo-acoustic arrays CHNAR, KSGAR, a triangular 1 km aperture. BRDAR consists of 5 short period vertical seismometers (GS-13) in seismic vaults and 13 microbarometers (Chaparral Model 2). Preliminary analysis using data collected from BRDAR shows an extension of infrasound detection capability to western part of the Korean Peninsula. Also, multiple observations of infrasound at BRDAR and other arrays gave an opportunity to localize sound source regions.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.29 no.6
• /
• pp.62-71
• /
• 2002

How parks are to be made in the twenty-first century should certainly be different. This is the inevitable conclusion of the recent significant international design competition for Downsview Park in Toronto, 2000. The purpose of this critical study is to investigate new strategies for urban park design manifested in the proposals of that competition and to explore alternative ways of landscape design that could solve the recent crisis of urban parks. Tree City, the winning entry, and other final entries proclaim that city is park and park is city. In this sense, Downsview Park marks the end of traditional Olmstedian parks and the dichotomy between city(culture) and park(nature). Rem Koolhaas and Bruce Mau's Tree City will become the model for urban park design in the near future. There are three reasons for this. First, its design is a strategy rather than a form. We can interpret that Tree City is to be developed over time as directed by six strategies: grow the park, manufacture nature, 1000 pathways, sacrifice and save, curate culture, destination and dispersal. Second, it places faith in landscape as a revenue generator instead of a fiscal liability. Third, its implementation is possible with crude installation, requiring virtually no craft. Koolhaas and Mau intend for Downsview to be an environment that is never actually designed but is formed through natural succession, cultural action, and programmatical insertions. Rather than designed objects and formal solutions, their strategy is to allow the landscape to evolve with changing uses.

• Journal of Information Processing Systems
• /
• v.16 no.3
• /
• pp.588-598
• /
• 2020

An alternative state estimation filtering algorithm is designed for continuous time systems with noises as well as control input. Two kinds of estimation filters, which have different measurement memory structures, are operated selectively in order to use both filters effectively as needed. Firstly, the estimation filter with infinite memory structure is operated for a certain continuous time system. Secondly, the estimation filter with finite memory structure is operated for temporarily uncertain continuous time system. That is, depending on the presence of uncertainty, one of infinite memory structure and finite memory structure filtered estimates is operated selectively to obtain the valid estimate. A couple of test variables and declaration rule are developed to detect uncertainty presence or uncertainty absence, to operate the suitable one from two kinds of filtered estimates, and to obtain ultimately the valid filtered estimate. Through computer simulations for a continuous time aircraft engine system with different measurement memory lengths and temporary model uncertainties, the proposed state estimation filtering algorithm can work well in temporarily uncertain as well as certain continuous time systems. Moreover, the proposed state estimation filtering algorithm shows remarkable superiority to the infinite memory structure filtering when temporary uncertainties occur in succession.

• Journal of the Korean earth science society
• /
• v.30 no.7
• /
• pp.883-896
• /
• 2009

This study is to develop teaching materials for geological fieldwork around Bonghwabong area in the national park of the Byeonsan Peninsula, Buangun, Jeonbuk. The developed materials are applied in the geological fieldwork of science high school students to maximize the effects of use. The sedimentary succession of the Bonghwabong area in the Cretaceous age, Mesozoic, represents large-scale and distinctive sedimentary structures on the sea cliffs, which are utilized as teaching materials for earth science fieldwork. The area of Bonghwabong also comprises various geological structures related to advanced learning programs as well as those within the curriculum of high school earth science. A five-step fieldwork model was applied to 15 students in clubs related to earth science in a science high school. This study used a qualitative methodology to analyze students' responses that were gathered about the process of fieldwork. During the activity, a qualitative analysis was carried out by using discussions and interviews both with the students and the teacher. Results indicated that the fieldwork activity using teaching materials was effective in helping the students improve their self-directed learning and practical understanding of earth science.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.21 no.6
• /
• pp.95-113
• /
• 2018

We studied the change of wetland vegetation structure to understand ecological restoration process of wetlands through the field survey of ecological restoration projects in Incheon, Iksan and Busan. We compared the vegetation plan at the time of planted with the results of the vegetation monitoring in 2018, and analyzed the changes in wetland vegetation structure. Based on results, we attempted to understand the restoration process of those wetlands and discuss the management measures for sustainable wetland restoration. As a result, in the Incheon Yeonhee restoration wetland, the number of plant species was increased, from 18 species in 2016 to 29 in 2018. The dominant species, Myriophyllum verticillatum, covered the wetland most and its occupied area was increased. On the other hand, the distribution area of the planted emergent hydrophytes was reduced. The area of open water decreased from 71.7% in 2016 to 48.8% in 2018. In Busan Igidae restoration wetland, the number of plant species was increased, from 6 species in 2014 to 31 in 2018. The dominant species was Myriophyllum verticillatum and its occupied area was increased. The area of floating plant communities that planned has decreased. The open water area decreased from 83.9% in 2014 to 31.8% in 2018. In Iksan Sorasan restoration wetland, the number of plant species was increased, from 13 species in 2016 to 36 in 2018. The dominant species was Phragmites communis Trin. and its occupied area was increased. The other planted species showed a tendency to be decreased by Phragmites communis Trin. and its terrestrialization. The open water area decreased from 86.6% in 2016 to 6.7% in 2018. These results suggest that wetlands should be managed by considering the change of vegetation structure and open water areas based on the following succession process, because it affects the habitat suitability of wetland organisms and biodiversity as well. Thus, the continuous monitoring for the ecological structure of restored wetland is important, and it could be possible step to develop sustainable wetland ecological restoration model.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.19 no.6
• /
• pp.111-121
• /
• 2016

This study was carried out to assess the riparian vegetation health in the fluctuation area and vicinity of reservoirs. The results of this study could be a basic data to improve the ecological function and establish green-network of waterside ecosystem. The study site is Daecheong lake reservoirs which the representative landscape of Geum river and with great number of visitors near metropolitan city. The 6 survey plots of 2 survey area were selected, survey area 1 had 4 survey plots and survey area 2 had 2 survey plots, and to compare the study results 4 control plots were selected in Gyeongcheon reservoir. The main dominant specie of survey sites was Salix koreensis in tree and subtree layer, were Salix koreensis and Salix glandulosa. in shrub layer. 2 survey plots of Samjeongdong and Kyeongcheon reservoir were assessed as 'Good', 2 survey plots of chudong were assessed as 'Fair' in vegetation health assessment. In the fluctuation area from flood water level to low water level, 58 populations of Salix koreensis were found in survey sites and Salix koreensis, Salix glandulosa and Acer tataricum subsp. ginale were found in control sites. The most adequate species at the condition affected by inundation impacts would be Salix koreensis and Salix glandulosa was more healthy at the area less affected by inundation. This study was carried out the vegetation health assessment on Daecheong reservoir which has been advanced natural succession for more than 30 years after the construction. Further, it should carry continuously out the research on the planting model of the waterside ecosystem for ecological restoration.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.3
• /
• pp.327-338
• /
• 1993

This paper proposes a novel method for deriving the Fourier transform pairs of high order pulses given in a generalized form. Primarily, modifying the PRS system model, we establish a new model which simplifies the process of Fourier analysis of the n-th order pulse signal, resulting in a representative relationship. In succession, we present the Frame Formula which plays a role of substituent for the parameters in table look-up procedures. Each look-up table contains all the parameters needed to obtain the Fourier transform of the corresponding pulse of any order. Regarding the amount of calculations and the complexity of procedures required to derive the transforms of pulse signals, analytically or numerically, this method is more compact and timesaving than conventional methods. When pulse has a much narrow width of equivalently higher the order of several pulses, the method presented here acts to the best of its true merit.

• Journal of Korean Society of Forest Science
• /
• v.94 no.6
• /
• pp.387-396
• /
• 2005

Having employed the transitional probability model based on Markov chain, the study was carried out to examine successional trends for community types in the natural deciduous forest of Mt. Jumbong. The species composition of oncoming generation in overstory was estimated from that of mid-story, and the species composition in mid-story was based upon that of understory. Successional trend for each community was predicted from the reorganized probability matrix of tree replacement by the square of climax index, which was evaluated by the factors of light absorption, reproduction, and wood quality. As the result of analysis, following table shows the oncoming generation of steady state and dominant species in overstory and mid-story by community types. Even though Acer pseudo-sieboldianum and Carpinus cordata could hardly reach the canopy layer due to the intrinsic growth form, these species were predicted to maintain high compositional ratio so as to play an important ecological role in the study forest ecosystem.

• Journal of Korean Society of Forest Science
• /
• v.81 no.4
• /
• pp.325-336
• /
• 1992

The successional status and potential natural vegetation were examined in a mixed broadleaved-Abies forest located at Mt, Odae National Park. The examination was based on the subsequent process of generation replacement by understory saplings for the dominant canopy trees within 88 $5m{\times}50m$ belt transects. The transition matrix model, which was modified from mathematical theory of Markov chain, was employed to analyze the successional status of the study forest. The model suggests that the study forest is still seral, and it is considered to be more than 700 years away from the steady state or climax in terms of species composition. The simulations predict a remarkable decrease in the proportion of species composition of the present dominant Quercus mongolica and Tilia amurensi.s from current 28% and 13% to less than 3% and 5%, respectively, at the steady state. On the contrary, the proportions of Abies holophylla, Acer pseudo-sieboldianum, Carpinus cordata, and Pinus koraiensis will increase at the steady state. The ratio of mixture between deciduous and coniferous trees will be gradually changed from current 6.5 : 3.5 to 5.0 : 5.0 at equilibrium. Discussion for the problems of Quercus mongolica in successional status noted that the species behaved as a mid-successional dominant, not a climax species in the study forest. The hypothesis and sensitivity of the transition matrix model were also discussed to evaluate the applicability to the real situation. The overall results indicated that the present dynamics of the forest must reflect the seral state due to previous disturbance mainly by hyman related interference.

• Geophysics and Geophysical Exploration
• /
• v.16 no.1
• /
• pp.27-35
• /
• 2013

In this study, we developed the trial product on 3D magnetic inversion tentatively named 'KMag3D'. Also, we briefly introduced its own function and graphic user interface on which especially focused through the development in the form of user manual. KMag3D is consisted of two fundamental frame for the 3D magnetic inversion. First, algebraic reconstruction technique was selected as a 3D inversion algorithm instead of least square method conventionally used in various magnetic inversion. By comparison, it was turned out that algebraic reconstruction algorithm was more effective and economic than that of least squares in aspect of both computation time and memory. Second, for the effective determination of the 3D initial and a-priori information model required in the execution of our algorithm, we proposed the practical technique based on the assemblage of 2D forward modeling and inversion results for individual user-selected 2D profiles. And in succession, initial and a-priori information model were constructed by appropriate interpolation along the strke direction. From this, we concluded that our technique is both suitable and very practical for the application of 3D magentic inversion problem.