• Journal of Ecology and Environment
• /
• v.34 no.2
• /
• pp.237-249
• /
• 2011

Land-use changes due to the socio-economic environment influence landscape patterns and processes, which affect habitats and biodiversity. This study considers the effects of such land-use changes, particularly on the traditional rural "Maeul" forested landscape, by analyzing landscape structure and vegetation changes. Three study areas were examined that have seen their populations decrease and age over the last few decades. Five types of plant life-forms (Raunkier life-forms) were distinguished to investigate ecosystem function. Principle component analysis was used to understand vegetation dynamics and community characteristics based on a vegetation similarity index. Ordination analysis transformed species-coverage data was introduced to clarify vegetation dynamics. Landscape indices, such as area metrics, edge metrics, and shape metrics, showed that spatial heterogeneity has increased over time in all areas. Pinus densiflora was the main land-use plant type in all study areas but decreased over time, whereas Quercus spp. increased. Over a decade, P. densiflora communities shifted to deciduous oak and plantation. These findings indicate that the impact of human activities on the Maeul landscape is twofold. While forestry activities caused heavy disturbances, the abandonment of traditional human activities has led to natural succession. Furthermore, it can be concluded that the type and intensity of these human impacts on landscape heterogeneity relate differently to vegetation succession. This reflects the cause and consequence of patch dynamics. We discuss an approach for sustainable landscape planning and management of the Maeul landscape based on traditional management.

• Journal of the Korean Geographical Society
• /
• v.36 no.2
• /
• pp.126-140
• /
• 2001

The influence of small urban parks(green ratio is 100%) on the temperature pattern over the urban and its surrounding area was examined by analyzing the case of in and around Changkyeong palace, Changdeok plalace and Jongmyo, Jongro-gu, Seoul. The pattern of temperature over urban parks and their surrounding built-up area was analyzed from September to November 2000, measuring maximum and minimum temperatures with fixed sensors(maximum and minimum thermometer)and real-time temperature depends largely on both the land-use type and the distance from the park border. In the case of maximum temperature, the lowest value appeared on the green area within parks and the highest value on the built-up area far from the green area. The maximum temperature difference between parks and built-up areas was up to $7.3^{\circ}C$. In the built-up area, the maximum temperature of commercial areas was higher than residential areas. In the night time, not only land-use type but also topography is important for the spatial distributlon of temperature because of the cold airflow from adjacet hills. The horizontal temperature profile by mobile measurement is also related to land-use type and to the distance from the park borders. There is a magnitude of $1^{\circ}C$ temperture difference over a distance of 200m and $3~4^{\circ}C$ over a distance of 400m from the park borders.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.10 no.1
• /
• pp.113-123
• /
• 2007

This study analyzed the appropriateness of the spatial distribution of fire stations and emergency medical facilities, the main providers of emergency medical care, in Busan. The area over which the 119 emergency medical services were situated in relation to the dispatch and transport of urgent rescue services was examined. Addresses of patients requiring 119 emergency services were obtained and stored as individual units so that they could be analyzed in a Geographic Information System(GIS). The time taken by emergency services to reach patients and transport them to a hospital or other facility was measured in seconds. By inputting additional information such as the location of the 119 dispatch centers, jurisdictions, and emergency medical facilities, the GIS allowed for analyses not only of the temporal but also the spatial aspects of emergency medical services. The results showed that of 16 Gu/Gun and 226 Eup/Myen/Dong in the Busan area, only 41% of Busan's emergency medical services could respond to and transport patients within five minutes. In all districts, most emergency medical services were provided within five to ten minutes. However, the pattern of hospital use to transfer patients to hospitals was inefficient. Based on the temporal and spatial distributions of fire stations and emergency medical agencies, and on their dispatch and transport times, this study sets out and compares ideal dispatch and transportation patterns for the efficient use of Busan's emergency medical services and resources.

• Journal of Korean Society for Geospatial Information Science
• /
• v.1 no.2 s.2
• /
• pp.159-166
• /
• 1993

Decrease of forest is seriously caused by urbanization. Photographic interpretation is the act of examining photographic images for the purpose of identifying objects and judging their significance. A systematic study of aerial photographs usually involves a consideration of the basic characteristics of photographic images. Seven of these characteristics are shape, size, pattern, shadow, tone, texture, and site. Aerial photographs contain a detailed record of the ground at the time of exposure. Authors blow the changes of natural environment by database for interpretation of aerial photo. In this paper, authors choose the Pusan National University located at the Kum-Joung Koo, Pusan as model area. Ten year of interval in 1980 and 1990, authors know the rate of forest decreasing is approximately 41 percents and the necessity of the protection of foreast. Authors suggest the combination of construction and protection of environment.

• The Journal of the Acoustical Society of Korea
• /
• v.25 no.6
• /
• pp.305-311
• /
• 2006

In this paper the performance of a array invariant method is evaluated for source-range estimation in horizontally stratified shallow water ocean waveguide. The method has advantage of little computationally effort over existing source-localization methods. such as matched field processing or the waveguide invariant and array gain is fully exploited. And. no knowledge of the environment is required except that the received field should not be dominated by purely interference This simple and instantaneous method is applied to simulated acoustic propagation filed for testing range estimation performance. The result of range estimation according to the SNR for the underwater impulsive source with broadband spectrum is demonstrated. The spatial smoothing method is applied to suppress the effect of mutipath propagation by high frequency signal. The result of performance test for range estimation shows that the error rate is within 20% at the SNR above 10dB.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.5
• /
• pp.132-141
• /
• 1996

The pixelated phase grating has been studied as a kind of diffraction gratings splitting and input beam into multiple spots. It consists of regular size cells which produce phase delays, and each cell provokes the phase delay up to sixteen levels. We have compared and analyzed the characteristics of multi-level phase gratings, laying streess on efficiency and resulted pattern. Experimental resutls obtained form fabricated grating have been presented, and the real-time method using a liquid-crystal spatial light modulator has been demonstrated through experiments. Gratings making meams with specific intensities have been designed and optical images have been generated by them. In order to specific intensities have been designed and optical images have been genrated by them. In order to decide the phase delay of each cell, optimization conditon consists of diffraction efficiency and target values. One period of phase gratings fabricated with surface relief was less than 256${\mu}m{\times}256{\mu}m$ and size of each cell was 1${\mu}m{\times}1{\mu}m$ surface relief grating has been made by coating photoresist on the glass plate, writing information pattern by Ar laser and developing it. in the experiment for real-tiem processing liquid-crystal display of epson video projector has been used.

• The KIPS Transactions:PartC
• /
• v.15C no.6
• /
• pp.513-522
• /
• 2008

Efficient data dissemination is one of the important subjects for sensor networks. High accessibility of the sensed data can be kept by deploying the data centric storage approach in which data is stored over the nodes in the sensor network itself rather than external storages or systems. The advantage of this approach is its direct accessibility in a real-time without the severe burden on delay and power dissipation on the data path to the external storages or systems. However, if the queries from many users are concentrated to the few nodes with data, then the response time could be increased and it could lead to the reduction of network life time by rapid energy dissipation caused by concentrated network load. In this paper, we propose a adaptive data centric storage scheme based on proxy trajectory (APT) mechanism. We highlight the data centric storage mechanism by taking account of supporting large number of users, and make it feasible to provide high-performance accessibility when a non-uniform traffic pattern is offered. Storing data around the localized users by considering spatial data-access locality, the proxy trajectory of APT provides fast response for the users. The trajectory, furthermore, may help the mobile users to roams freely within the area they dwell.

• Journal of the Korean Geographical Society
• /
• v.40 no.3 s.108
• /
• pp.310-320
• /
• 2005

This study attempts at prototyping and evaluating a geovisualization tool that summarizes and explores human activity patterns using spatio-temporal trajectory data collected from GPS receiver. A set of core conceptualization developed in 'time geography' is successfully represented by our prototype based on the notion of 'space-time cube.' The notions of 'temporal dispersion cylinder' and 'parallel plane plot' are also implemented to allow funker analyses of human activity pattern on the space-time trajectory. The capabilities of the geovisualization environment we proposed include the interactive and dynamic functions that support a variety of explorations on the three components of spatio-temporal data : space(where), time(when), and object(what).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.510-512
• /
• 2018

The proposed method enhances the resolution of images by removing noise using wavelet transform to remove noise from images generated by ultrasound diagnosis. We propose an algorithm to reduce the speckle noise and enhance the edge of the ultrasound image. The proposed algorithm can enhance edges of various sizes by using wavelet transform which can use both frequency and spatial information. Experimental results show that the performance of the algorithm for noise reduction of ultrasound images is about 0.45ms for $520{\times}440$ images.

• Korean Journal of Cognitive Science
• /
• v.21 no.2
• /
• pp.309-338
• /
• 2010

In this paper, we studied the brain-computer interface (BCI). BCIs help severely disabled people to control external devices by analyzing their brain signals evoked from motor imageries. The findings in the field of neurophysiology revealed that the power of $\beta$(14-26 Hz) and $\mu$(8-12 Hz) rhythms decreases or increases in synchrony of the underlying neuronal populations in the sensorymotor cortex when people imagine the movement of their body parts. These are called Event-Related Desynchronization / Synchronization (ERD/ERS), respectively. We implemented a BCI-based mouse interface system which enabled subjects to control a computer mouse cursor into four different directions (e.g., up, down, left, and right) by analyzing brain signal patterns online. Tongue, foot, left-hand, and right-hand motor imageries were utilized to stimulate a human brain. We used a non-invasive EEG which records brain's spontaneous electrical activity over a short period of time by placing electrodes on the scalp. Because of the nature of the EEG signals, i.e., low amplitude and vulnerability to artifacts and noise, it is hard to analyze and classify brain signals measured by EEG directly. In order to overcome these obstacles, we applied statistical machine-learning techniques. We could achieve high performance in the classification of four motor imageries by employing Common Spatial Pattern (CSP) and Linear Discriminant Analysis (LDA) which transformed input EEG signals into a new coordinate system making the variances among different motor imagery signals maximized for easy classification. From the inspection of the topographies of the results, we could also confirm ERD/ERS appeared at different brain areas for different motor imageries showing the correspondence with the anatomical and neurophysiological knowledge.