• Geophysics and Geophysical Exploration
• /
• v.20 no.4
• /
• pp.199-206
• /
• 2017

Field data obtained from marine exploration are influenced by various environmental factors such as wind, waves, tidal current and flow velocity of a background medium. Most environmental factors except for the flow velocity are properly corrected in the data processing stage. In this study, the wave equation modeling considering flow velocity is used to generate observation data, and numerical experiments using the observation data were conducted to analyze the effect of flow velocity on waveform inversion. The numerical examples include the results with unrealistic flow velocities. In addition, an algorithm is suggested to numerically extract flow velocity for waveform inversion. The proposed algorithm was applied to the modified Marmousi2 model to obtain the results depending on the flow velocity. The effect of flow velocity on updated physical properties was verified by comparing the inversion results without considering flow velocity and those obtained from the proposed algorithm.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.3
• /
• pp.147-152
• /
• 2008

Ant System(AS) is new meta heuristic for hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem. In this paper, AS is applied to the Multicast Routing Problem. Multicast Routing is modeled as the NP-complete Steiner tree problem. This is the shortest path from source node to all destination nodes. We proposed new AS to resolve this problem. The proposed method selects the neighborhood node to consider all costs of the edge and the next node in state transition rule. Also, The edges which are selected elite agents are updated to additional pheromone. Simulation results of our proposed method show fast convergence and give lower total cost than original AS and $AS_{elite}$.

• Journal of KIISE:Software and Applications
• /
• v.33 no.8
• /
• pp.692-702
• /
• 2006

In this study, a weighted fuzzy min-max (WFMM) neural network model for pattern classification is proposed. The model has a modified structure of FMM neural network in which the weight concept is added to represent the frequency factor of feature values in a learning data set. First we present in this paper a new activation function of the network which is defined as a hyperbox membership function. Then we introduce a new learning algorithm for the model that consists of three kinds of processes: hyperbox creation/expansion, hyperbox overlap test, and hyperbox contraction. A weight adaptation rule considering the frequency factors is defined for the learning process. Finally we describe a feature analysis technique using the proposed model. Four kinds of relevance factors among feature values, feature types, hyperboxes and patterns classes are proposed to analyze relative importance of each feature in a given problem. Two types of practical applications, Fisher's Iris data and Cleveland medical data, have been used for the experiments. Through the experimental results, the effectiveness of the proposed method is discussed.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.7 no.4
• /
• pp.15-23
• /
• 2004

In order to utilize remote sensed images effectively, it is necessary to correct geometric distortion. Geometric correction is a critical step to remove geometric distortions in satellite images. For geometric correction, Ground Control Points (GCPs) have to be chosen carefully to guarantee the quality of geocoded satellite images, digital maps, GPS surveying or other data. Traditional approach to geometric correction used GCPs requires substantial human operations. Also that is necessary much time and manpower. In this paper, we presented an on-line automatic geometric correction by constructing GCP Chip database. The Proposed on-line automatic geometric correction system is consists of four part. Input image, control the GCP Chip, revision of selected GCP, and output setting part. In conclusion, developed system reduced the processing time and energy for tedious manual geometric correction and promoted usage of Landsat imagery.

• Spatial Information Research
• /
• v.9 no.2
• /
• pp.263-275
• /
• 2001

With increasing of utilization of 1/1,000 Digital-Map being constructed with NGIS project, it is entering upon the stage that problem as the inspection of position accuracy of Digital-Map before its use. This paper evaluated position accuracy of Digital-Map being based on the construction of college facility management system into small area and presented modification/renovation of Digital-Map on area being occurred position error. With a view to evaluation of position error to building using RTK survey, position error was shown more than 0.5mm that is prescribed in survey-law. In order to acquire good position accuracy, first we carried out Static survey to college and selected control point. And, we evaluated coordinate value to important building from control point and compared these results with RTK survey results. Second, we carried out Affine transform based on the control point of building being surveyed with RTK, transformed pre-constructed Digital-Map and compared these results with RTK Survey results. We analyzed first and second method and presented improvement method of position accuracy of Digital-Map suited on small area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.20 no.1
• /
• pp.59-67
• /
• 2002

Recently, much demand of vector data have increased rapidly such as a digital map instead of traditional a paper map and the raster data such as a high-resolution orthoimage have been used for many GIS application with the advent of industrial high-resolution satellites and development of aerial optical sensor technologies. Aerial photogrammetric technologies using an airship can offer cost-effective and high-resolution color images as well as real time images, different from conventional remote sensing measurements. Also, it can acquire images easily and its processing procedure is short and simple relatively. On the other hand, it has often been used for the production of a small-scale land use map not required high accuracy, monitoring of linear infrastructure features through mosaicking strip images and construction of GIS data. Through this study, the developed aerial photogrammetric system using the airship expects to be applied to not only producing of scale 1:5, 000 digital map but also verifying, editing, and updating the digital map which was need to be reproduced. Further more, providing the various type of video-images, it expects to use many other GIS applications such as facilities management, scenery management and construction of GIS data for Urban area.

• Journal of the Institute of Convergence Signal Processing
• /
• v.5 no.3
• /
• pp.190-197
• /
• 2004

This paper presents automated prediction of transient ischemic episodes using neural networks(NN) based pattern matching method. The learning algorithm used to train the multilayer networks is a modified backpropagation algorithm. The algorithm updates parameters of nonlinear function in a neuron as well as connecting weights between neurons to improve learning speed. The performance of the method was evaluated using ECG signals of the MIT/BIH long-term database. Experimental results for 15 records(237 ischemic episodes) show that the average sensitivity and specificity of ischemic episode prediction are 85.71% and 71.11%, respectively. It is also found that the proposed method predicts an average of 45.53［sec］ ahead real ischemia. These results indicate that the NN approach as the pattern matching classifier can be a useful tool for the prediction of transient ischemic episodes.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.07a
• /
• pp.652-654
• /
• 2005

WebDAV는 웹통신 프로토콜인 HTTP/1.1의 확장으로서 인터넷을 통하여 다양한 자원의 비동기적인 협업을 지원하는 표준 프로토콜이다. CoSlide 시스템은 협업을 효과적으로 지원하기 위하여 WebDAV 프로토콜을 확장하여 개발된 협업시스템이다. CoSlide 협업시스템은 협업을 위한 가상공간을 제공하며 가상공간에 다양한 자원을 등록 및 관리할 수 있다. CoSlide 협업시스템을 활용하여 효과적인 협업을 수행하기 위한 사용자 중심의 클라이언트가 필요하다. 본 논문에서는 WebDAV 프로토콜을 이용한 협업시스템인 Coslide를 효과적으로 활용하기 위한 클라이언트 개발에 대하여 기술한다. 개발된 클라이언트는 사용자가 서버에 등록한 자원을 관리하는 기능과 팀원들 간의 상호 작용을 원활하게 지원하는 사용자 인터페이스를 제공한다. 또한 CoSlide 협업시스템을 사용하는 사용자는 새로운 작업장을 생성하고 다른 사용자를 초대할 수 있으며, 작업장에 파일을 등륵, 이동 그리고 삭제할 수 있다. 기존의 협업시스템에서 분산저작을 하는 경우 클라이언트에서 제공하는 특정 프로그램을 이용하거나, 파일을 서버로부터 내려받아 이를 수정하여 다시 등록하는 과정을 거친다. 본 클라이언트는 이러한 단점을 개선하여 CoSlide 협업시스템의 자원에 대하여 다양한 저작프로그램을 자동적으로 연결하여주며, 실시간으로 협업시스템의 자원을 갱신하여 준다. 또한 자원에 대한 일관성을 보장하기 위하여 자동 잠금기능을 제공한다. 추가적으로 사용자는 드래그앤드랍 기능을 이용하여 작업장간의 자원을 이동할 수 있다.

• Journal of KIISE:Databases
• /
• v.36 no.1
• /
• pp.1-7
• /
• 2009

Flash memory has its unique characteristics: i.e., (1) the write operation is much more costly than the read operation. (2) In-place updating is not allowed. In this paper, we first analyze how these characteristics affect the performance of record management in flash memory, and discuss the problems with previous methods for record management when they are applied to flash memory environment. Next, we propose a new record management method to be suitable for flash memory environment. The proposed method employs a new concept of a container that makes it possible to overwrite data on flash memory several times when performing insertions, deletions, and modifications of records. As a result, this method reduces the number of overwrite operations, and consequently does the number of erase operations. The results of experiments show that our method improves the performance by up to 34%, compared with the previous one.

• The Journal of the Korea Contents Association
• /
• v.9 no.6
• /
• pp.436-443
• /
• 2009

There have been rapid increases to the demands for modeling diverse and complex spatial phenomena and utilizing spatial data through the computer across all the aspects of society. As a result, the importance and utilization of remote sensing and GIS's(geographic information systems) have also increased. It can produce digital data of enormous accuracy and value by incorporating remote sensing images into GIS analysis technology and make various thematic maps by classifying and analyzing land cover. Once such a map is made for the target area, it can easily do modeling and constant monitoring based on the map, revise the database with ease, and thus efficiently update geo-spatial information. Under the goal of analyzing changes to land cover along the road by combining the remote sensing and GIS technology, this study classified land cover from the images of two periods, detected changes to the six classes over ten years, and obtained statistics about the study area's quantitative area changes in order to provide basic decision making data for urban planning and development. By analyzing land use along the road, one can set up plans for the area along the road and the downtown to supplement each other.