• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12B
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• pp.818-830
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• 2005

Recently, Peer-to-Peer (P2P) overlay networks like CAN, Chord, Pastry and Tapestry offer a novel platform for scalable and decentralized distributed applications. These systems provide efficient and fault-tolerant routing, object location, and load balancing within a self-organizing overlay network. Content Delivery Network (CDN) is an intermediate layer of infrastructure that helps to efficiently deliver the multimedia content from content providers to clients. In this paper, We propose a topology-aware P2P overlay network for CDN, Rosary, in which CDN servers perform Intra-Pastry and Inter-Pastry routing based on a two-level structured overlay network. This proposed system extends pastry by adapting itself to CDN environments, where a semi-hashing based scheme for Intra-Pastry routing is introduced, and dynamic landmark technology is used to construct the topology-aware overlay network. Through simulations on NS-2, it is shown that Rosary is scalable, efficient, and flexible.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.5
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• pp.435-444
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• 2012

Although the multi-scale map database should be constructed for the web map services and location-based services, much part of generation process is based on the manual editing. In this study, the map generalization methodology for automatic construction of multi-scale database from the primary data is proposed. Moreover, the generalization methodology is applied to the real map data and the prototype of multi-scale map dataset is generated. Among the generalization operators, selection/elimination, simplification and amalgamation/aggregation is applied in organized manner. The algorithm and parameters for generalization is determined experimentally considering T$\ddot{o}$pfer's radical law, minimum drawable object of map and visual aspect. The target scale level is five(1:1,000, 1:5,000, 1:25,000, 1:100,000, 1:500,000) and for the target data, new address data and digital topographic map is used.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.65-76
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• 2004

This paper suggests design and implementation of moving objects management system using GML which is the XML encoding standard of geographic data. The proposed system integrates spatial data and moving objects data, utilizing the concept of Web Feature Services. While integrating data, standard data model and interfaces, proposed by OGC, are used. Since GML is standard for storing and transferring spatial/non-spatial data, interoperability and extendibility can be obtained. In addition, we propose efficient developing environment for the moving object management system by providing components having Web/Mobile interface. If the proposed component be development methods are used, it is easy to add or modifyservices in the mobile system and pla

• Korean Journal of Bronchoesophagology
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• v.10 no.1 s.19
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• pp.46-50
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• 2004

The majority of esophageal Foreign body ingestions occur in the pediatric population. In adults, true foreign object ingestion occurs more commonly among those with psychiatric disorders, mental impairment. The management of esophageal foreign bodies is influenced by the age, clinical condition of ingested material, anatomic location and technical abilities of the endoscopist. Recently the therapeutic endoscopy is becoming wider and more rational in application. We evaluated the role of endoscopy for removal of esophageal foreign bodies during the period of 4 years from January 2000 to December 2003 at the Department of Otolaryngology and Gastroenterology, Seonam University Hospital. The results were as follow, 1) The age ranged from 21 to 74 years old (mean 50.5), most frequent age group was between 61-70 years old and male to female ratio was 1:1.4. 2) Fish bone was the most frequent foreign body in the esophagus ($47.1\%$), food material ($23.5\%$) and meats ($17.6\%$) were next frequent foreign bodies. The most frequent site of lodgement was the first ($78.4\%$), second ($17.6\%$) and third narrowing ($3.9\%$) in order. 3) The most common symptom was foreign body sensation (28.6%). the next common symptoms were chest discomfort($23.8\%$) and dysphagia($19\%$). 4) In duration of lodgement, 49cases ($96.1\%$) were lodged for less than one day. 5) The foreign bodies of esophagus were removed successfully by flexible endoscope with basket, snare, forceps, overtube and endoscopic variceal ligation cap. There were only 3 cases of minimal complications, esophageal mucosal tearing. In conclusion, endoscopic esophageal foreign body removal is useful and safe with minimal or no complications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.603-607
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• 2004

The vision-based driver fatigue detection is one of the most prospective commercial applications of facial expression recognition technology. The facial feature tracking is the primary technique issue in it. Current facial tracking technology faces three challenges: (1) detection failure of some or all of features due to a variety of lighting conditions and head motions; (2) multiple and non-rigid object tracking and (3) features occlusion when the head is in oblique angles. In this paper, we propose a new active approach. First, the active IR sensor is used to robustly detect pupils under variable lighting conditions. The detected pupils are then used to predict the head motion. Furthermore, face movement is assumed to be locally smooth so that a facial feature can be tracked with a Kalman filter. The simultaneous use of the pupil constraint and the Kalman filtering greatly increases the prediction accuracy for each feature position. Feature detection is accomplished in the Gabor space with respect to the vicinity of predicted location. Local graphs consisting of identified features are extracted and used to capture the spatial relationship among detected features. Finally, a graph-based reliability propagation is proposed to tackle the occlusion problem and verify the tracking results. The experimental results show validity of our active approach to real-life facial tracking under variable lighting conditions, head orientations, and facial expressions.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.6
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• pp.25-35
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• 2006

Radio Frequency identification (RFID) will become an important technology in remotely object identification systems. However, the use of RFID tags may create new threats to the sniな and Privacy of individuals holding RFID tags. These threats bring several problems which are information leakage of a tag, location trace of individuals and impersonation of a tag. Low-cost RFID systems have much restrictions such as the limited computing power, passive power mechanism and low storage space. Therefore, the cost of tag's computation should be considered as an important factor in low-cost RFID systems. We propose an authentication protocol, OHLCAP which requires only one one-way hash function operation and hence is very efficient. Furthermore, our protocol is suitable to distribution database environment. Hence our scheme can be applied to ubiquitous computing environment.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.699-706
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• 2021

Existing license plate recognition system is used as an optical character recognition method, but a method of using deep learning has been proposed in recent studies because it has problems with image quality and Korean misrecognition. This requires a lot of data collection, but the collection of license plates is not easy to collect due to the problem of the Personal Information Protection Act, and labeling work to designate the location of individual license plates is required, but it also requires a lot of time. Therefore, in this paper, to solve this problem, five types of license plates were created using a virtual Korean license plate generation program according to the notice of the Ministry of Land, Infrastructure and Transport. And the generated license plate is synthesized in the license plate part of collectable vehicle images to construct 10,147 learning data to be used in deep learning. The learning data classifies license plates, Korean, and numbers into individual classes and learn using YOLOv5. Since the proposed method recognizes letters and numbers individually, if the font does not change, it can be recognized even if the license plate standard changes or the number of characters increases. As a result of the experiment, an accuracy of 96.82% was obtained, and it can be applied not only to the learned license plate but also to new types of license plates such as new license plates and eco-friendly license plates.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.133-140
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• 2006

This paper suggests to reclassify railroad accident types and to standardize them as the standardized code for the railroad safety management system. The existing railroad accident types in both domestic and foreign cases have been carefully analyzed in the beginning. Based on the case studies, the new railroad accident types are classified into 9 classes which are not overlapped one another and 9 classes have been subdivided into 40 different accident patterns. All these patterns are linked with 9 different accident objects and 6 accident locations. Therefore, this study suggested the combination of 4 distinct code factors: accident class, accident pattern, accident object, and accident location to standardize them. In addition, inter-operation between the proposed codes and the existing accident types is suggested. This code will play a major role in the railroad safety management system composed of accident prevention, accident preparedness, accident response, and accident recovery.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.10-20
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• 2024

In recent automated manufacturing systems, compressed air-based pneumatic cylinders have been widely used for basic perpetration including picking up and moving a target object. They are relatively categorized as small machines, but many linear or rotary cylinders play an important role in discrete manufacturing systems. Therefore, sudden operation stop or interruption due to a fault occurrence in pneumatic cylinders leads to a decrease in repair costs and production and even threatens the safety of workers. In this regard, this study proposed a fault detection technique by developing a time-variant deep learning model from multivariate sensor data analysis for estimating a current health state as four levels. In addition, it aims to establish a real-time fault detection system that allows workers to immediately identify and manage the cylinder's status in either an actual shop floor or a remote management situation. To validate and verify the performance of the proposed system, we collected multivariate sensor signals from a rotary cylinder and it was successful in detecting the health state of the pneumatic cylinder with four severity levels. Furthermore, the optimal sensor location and signal type were analyzed through statistical inferences.

• Journal of Digital Convergence
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• v.12 no.8
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• pp.467-474
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• 2014

Augmented reality in the smart environments is the interaction between the user and the media through the expansion of a variety of experiences is provided. How to use the location information, how to use markers, utilizing real-time marker-less interaction with the real world and the virtual world, such as the mapping method intermediary situated in real-time. Expansion of the elements of experience, and augmented reality as a tool of information being utilized. Educational Edutainment AR card to take advantage in terms of content was a real-time marker-less approach to create an image map image map was constructed urbanization. Stereoscopic 3D environment, taking advantage of the object produced by combining augmented reality and way of interaction, educational content. Help in terms of active and passive involvement pra realistic interest leads to a way of giving tangible.