• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.2
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• pp.157-168
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• 1993

In this paper, it is shown that neural networks trained with back propagation algorithm and dictionary can be applied to recognize handwritten English characters. To eliminate the useless data part and to minimize the variety of characters from the scanned image file, various preprocessings : that is, segmentation, centering, noise filtering, sealing and thinning are performed. After these, characteristic features are derived from thinned character pattern. The neural network is trained by using the extracted features for sample data, and all test data are classified into English alphabets according to their features through the neural network. Finally, the ways of reducing learning time and improving recognition rate, and the relationship between learning time and hidden layer nodes are considered. As a result of this study, after successful training, a high recognition rate has been obtained with this system for the trained patterns and about 93% for test patterns. Using dictionary, the recognition rate was about 97% for test pattern.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.377-385
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• 2010

In this paper, we propose a SInk-initiated geographic Multicast (SIM) protocol to reduce frequent location updates from mobile sinks to a source and to achieve fast multicast tree construction and data delivery. The proposed protocol allows sinks to construct their own data delivery paths to a source node and a multicast tree to be atomically constructed by merging the paths. Then, the source forwards data to the destinations down the multicast tree. This paper also propose a round-based virtual infrastructure with a radial shape for increasing the merging probability of data delivery paths and reducing reconstruction ratio of the multicast tree due to mobility of sinks. Simulation results show that the proposed protocol is superior to previous SOurce-initiated geographic Multicast (SOM) protocols in term of average data delivery delay and average energy consumption.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.9
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• pp.247-260
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• 2016

Sensor networks have been used in many applications such as smart home, smart factory, etc. based on sensor data. Sensor networks can change system requirements and architectures depending on their application areas. Currently, sensor network application cases in ocean environments are very rare because the ocean environments have much difficult accessibility more poor conditions, higher wave heights, more frogs, much heavier salinity, etc., compared with ground environments. In this paper, we propose the requirements, architecture and design of a sensor network system for the littoral sea cage culture monitoring and we also introduce its operation results through the development. The developed system based on our research provides users with functionalities to extract, monitor, and manage underwater environmental conditions suitable to littoral sea cage culturing of fishes.

• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.329-339
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• 2005

In the mobile phone map service there are some restrictions of resolutions and process in terminals. So providing a sketch map is very efficient. This simplifies the map data and increases the understanding of the user. This sketched map marks the starting point and ending point. Then simplifies the surroundings like important roads or building so the user can find his/her way easily. First of all this sketch map service needs a method to simplify the route between starting point and ending point and the surroundings. After that it needs to make the simplified data into a sketch map and suitable to the terminal's resolution. To solve these problems this paper proposes a new method to manifest a sketch map efficiently through a mobile phone. The method, introduced in this paper, is surveyed to have a higher efficiency in data usage compared to the current services available in the market. And also it is examined to have a clear vision in process and easily understandable.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1121-1132
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• 2021

Nowadays, it is more difficult to find people who do not use mobile devices such as smartphones and tablets. Contents that can be accessed at the touch of a finger is overflowing. However, the existing network has a structure in which it is difficult to efficiently respond to the problems caused by overflowing contents. In particular, the bottleneck problem that occurs when multiple users intensively request content from the server at the same time is a representative problem. To solve this problem, the CCN has emerged as an alternative to future networks. CCN uses the network bandwidth efficiently through the In-Network Cache function of the intermediate node to improve the traffic required for user to request to reach the server, to reduce response time, and to distribute traffic concentration within the network. I propose a cache policy that can improve efficiency in such a CCN environment.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.599-607
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• 2021

Street-view images, which are omnidirectional scenes centered on a specific location on the road, can provide various obstacle information for the pedestrians. Pedestrian network data for the navigation services should reflect the up-to-date obstacle information to ensure the mobility of pedestrians, including people with disabilities. In this study, the object detection model was trained for the bollard as a major obstacle in Seoul using street-view images and a deep learning algorithm. Also, a process for updating information about the presence and number of bollards as obstacle properties for the crosswalk node through spatial matching between the detected bollards and the pedestrian nodes was proposed. The missing crosswalk information can also be updated concurrently by the proposed process. The proposed approach is appropriate for crowdsourcing data as the model trained using the street-view images can be applied to photos taken with a smartphone while walking. Through additional training with various obstacles captured in the street-view images, it is expected to enable efficient information update about obstacles on the road.

• Journal of Korean Society of Archives and Records Management
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• v.22 no.4
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• pp.87-107
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• 2022

This study aims to examine the meaning and category of archival information services and analyze its research results. To this end, the research scope of the archival information service was set by reviewing the definition, types, and subjects. A total of 183 journal articles were gathered, and content analysis was conducted in two stages. In addition to the overall research trend analysis based on quantitative indicators, an expanded content analysis and language network analysis were attempted using Node Excel. This study revealed that the archival information service research began in earnest after 2006 and that the user-centered paradigm is gradually being applied. However, limitations confirmed that the subject of discussion, research methods, and journals were biased, and expanding the horizon of future discussion was suggested.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.12
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• pp.533-540
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• 2016

Information Visualization is an information technology to visually represent the data and information by utilizing various tools. Visual information can increase the user's intuitiveness and it can be an effective way that can observe and comprehend the specific information in a short time. Information Visualization, as a research method on Humanities, in the high interest of researchers of Humanities and Area studies, is recently used for collecting base data and analyzing information. As an way to use Information Visualization, various forms of Information Visualization like Electronic Cultural Atlas, Network and Multimedia are actively discussed and studied today. In this paper, Information Visualization will be discussed by utilizing D3, a web-based technology for dynamic visualization. In detail, relationship between the Abbasids of Islam can be visualized by using nodes and connection lines and, this relationship between objects will be analyzed efficiently. Researchers related in this field can use this analyzed information for basis data in their researches.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.413-413
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• 2020

Godunov형 모형을 이용한 홍수모델링에서는 일반적으로 구조적 사각격자나 비구조적 삼각격자가 주로 적용된다. 2차원 수치모형을 이용한 홍수모델링에서 연구유역의 정보가 격자의 노드나 중심에 입력되므로 적용격자의 유형과 생성방법에 따라 모형의 입력자료 오차에 영항을 줄 수 있다. 따라서, 연구유역이 지형 변동성이 심한 지역이거나 흐름형상이나 흐름변동이 심한 구간이라면, 고해상도 격자를 통해 모형의 입력자료 오차를 최소화할 할 수 있다. 본 연구에서는 2가지 유형에 대한 연구를 수행하였다, 첫 번째는 홍수해석을 위한 2차원 모형의 격자형상과 해상도에 따른 홍수위 및 홍수범람범위를 비교·분석하는 연구를 수행하였다. 연구유역은 2000년 10월 29일부터 11월 19일까지 홍수가 발생한 영국의 Severn 강 유역이다. 연구유역의 홍수 모델링을 위한 지형자료는 3m 해상도의 LiDAR(Light Detection And Ranging)를 이용하여 구축하였으며, 격자유형 및 해상도에 따른 2차원 홍수위 및 홍수범람범위를 비교·분석하기 위해서 홍수 발생기간 동안 촬영된 4개(2000년 8월 11, 14, 15, 17일)의 ASAR(Advanced Synthetic Aperture Radar) 영상자료를 활용하였다. 즉, ASAR 영상으로 촬용된 최대범람시기 및 홍수류의 배수기를 활용하여 최대범람범위뿐만 아니라 홍수가 증가하는 시기와 하류단 배수로 인해 홍수가 감소하는 시기를 모두 포함하는 홍수범람범위에 대한 격자유형별 2차원 홍수범람모형의 계산 결과에 대해 비교하였다. 두 번째는 아마존 강 중류유역의 2,500K㎡ 면적에 해당하는 대규모 유역에 대해 SRTM(Shuttle Radar Topography Mission) 지형자료를 이용하여 홍수기와 갈수기에 대해 2차원 모델링을 수행하고 그 결과를 위성자료와 비교하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1095-1102
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• 2023

Content Centric Network (CCN) is a network that emerged to improve the existing network structure and communicates based on content names instead of addresses. It utilises caches to distribute traffic and reduce response time by delivering content from intermediate nodes. In this paper, we propose a popularity-based caching policy to efficiently utilise the limited CS space in CCN environment. The performance of CCNs can vary significantly depending on which content is prioritised to be stored and released. To achieve the most efficient cache replacement, we propose a real-time content popularity-based efficient cache replacement policy that calculates and prioritises content popularity based on constructor popularity, constructor distance, and content hits, and demonstrate the effectiveness of the new policy through experiments.