• Spatial Information Research
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• v.19 no.1
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• pp.107-116
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• 2011

Due to development of environment of wireless Internet, location based services on the basis of spatial data have been increased such as real time traffic information as well as CNS(Car Navigation System) to provide mobile user with route guidance to the destination. However, the current application adopting the file-based system has limitation of managing and storing the huge amount of spatial data. In order to supplement this challenge, research which is capable of managing large amounts of spatial data based on embedded database system is surely demanded. For this reason, this study aims to suggest the lossless compression technique by using the hybrid approach of BytePacking and Lempel-Ziv which can be applicable in DBMS so as to save a mass spatial data efficiently. We apply the proposed compression technique to actual the Seoul and Inchcon metropolitan area and compared the existing method with suggested one using the same data through analyzing the query processing duration until the reconstruction. As a result of comparison, we have come to the conclusion that suggested technique is far more performance on spatial data demanding high location accuracy than the previous techniques.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.6
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• pp.718-731
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• 2003

SAN(Storage Area Network) was developed in response to the requirements of high availability of data, scalable growth, and system performance. In order to use the SAN more efficiently, most of the SAN operating software supports storage virtualization concepts that allow users to view physical storage devices of the SAN as a large volume. A logical volume manager plays a key role in storage virtualization. It realizes the storage virtualization by mapping logical addresses to physical addresses. In this paper, we design and implement an efficient and flexible mapping method for the logical volume manager. Additionally we also design and implement a free space management method for flexible mapping. Our mapping method supports a snapshot that preserves a volume image at certain time and on-line reorganization to allow users to add or remove storage devices to and from the SAN even while the system is running. To justify our mapping method, we compare it with the mapping method of the GFS (Global File System) through various experiments.

• KIISE Transactions on Computing Practices
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• v.22 no.1
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• pp.20-25
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• 2016

With the advent of the era of digital big data, the Hadoop platform has become widely used in various fields. However, the Hadoop MapReduce framework suffers from problems related to the increase of the name node's main memory and map tasks for the processing of large number of small files. In addition, a method for running C++-based tasks in the MapReduce framework is required in order to conjugate GPUs supporting hardware-based data parallelism in the MapReduce framework. Therefore, in this paper, we present a face detection system that generates a sequence file for images to process big data for images in the Hadoop platform. The system also deals with tasks for GPU-based face detection in the MapReduce framework using Hadoop Pipes. We demonstrate a performance increase of around 6.8-fold as compared to a single CPU process.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.2
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• pp.1-10
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• 2022

Deception technology is an extended concept of honeypot, which detects, prevents or delays attacks by deceiving adversaries. It has been applied to various system components such as network ports, services, processes, system calls and database management systems. We can apply the same concept to attacks on files. A representative example of a file attack is ransomware. Ransomware is a type of malware that encrypts user files and ask for ransom to recover those files. Another example is the wiper attack, which erases all or target files of a system. In this paper we propose a defense mechanism against these kinds of attacks by hiding files. Compared to backup or virtualization techniques, the proposed method incurs less space and performance overheads.

• The Journal of the Acoustical Society of Korea
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• v.39 no.4
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• pp.286-291
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• 2020

In this paper, we propose a system that recommends music through tempo-oriented music classification and sensor-based human activity recognition. The proposed method indexes music files using tempo-oriented music classification and recommends suitable music according to the recognized user's activity. For accurate music classification, a dynamic classification based on a modulation spectrum and a sequence classification based on a Mel-spectrogram are used in combination. In addition, simple accelerometer and gyroscope sensor data of the smartphone are applied to deep spiking neural networks to improve activity recognition performance. Finally, music recommendation is performed through a mapping table considering the relationship between the recognized activity and the indexed music file. The experimental results show that the proposed system is suitable for use in any practical mobile device with a music player.

• Korean Journal of Digital Imaging in Medicine
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• v.11 no.1
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• pp.35-41
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• 2009

This study was conducted to improve performance flow of PACS registration and output of external medical images by developing or adding File Transfer Protocol(FTP) Module on Order Communication System(OCS) and to upgrade efficiency of performance. The numbers of requests for examination of external medical images from January 2004 to December 2007 were investigated and the numbers of cases of examinations and losses were done respectively from January to June, 2007 as a period before the improvement and from July to December, 2007 as a period after it. Satisfaction of persons inputting external medical images of CD was asked directly before and after the improvement. When the numbers of requests for examination of external medical images from 2004 to 2007 2004 were investigated, they were 12,783, 16,774, 21,613 and 27,487 cases in 2004, 2005, 2005 and 2007 respectively. For the numbers of the requests from January to December, 2007 it was the lowest in February by recording 1846 and it was 2800 in October. While the number of loss of external medical images was averagely 3.6 before using FTP Module on OCS, it reduced to 0 and satisfaction increased to 98% after it. By utilizing FTP Module on OSC for PACS registration of external medical images, the images were delivered simultaneously with occurrence of order, PACS registration of many patients was conducted together and CDs were returned to patients immediately after sending images from outpatient clinics or wards to remove possibility of losing them. In addition, because the module was established on OCS and data were sent associated with order, problems related with order were decreased. By eliminating movement distance it was turned out to be very effective in terms of time and space.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.127-132
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• 2014

In this paper, we propose a digital signage method that can control the contents of the screen and download the desired files to individual smart terminal with no touch of digital signage screen by using Kinect. The main features and contributions of the proposed method are as follows. First, can solve the problems such as the risk of bacterial infection, not cleanliness on the screen as well as maximize advertising effectiveness. Second, can support bi-directional communications with computer while we touch only wanted advertisements. The performance evaluation shows the effectiveness of the proposed method. Especially, we can see that the proposed system operates through the recognition of user's actions when the cursor is within the scope of a certain coordinate and the file transfer time to download information is different depending on the PC performance and the version of personal smart device.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.175-178
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• 2008

While read operation on flash memory is fast and doesn't have any constraints, flash memory can not be overwritten on updating data, new data are updated in new area. If data are frequently updated, garbage collection, which is achieved by erasing blocks, should be performed to reclaim new area. Hence, because the number of erase operations is limited due to characteristics of flash memory, every block should be evenly written and erased. However, if data with access locality are processed by cost benefit algorithm with separation of hot block and cold block, though the performance of processing is high, wear-leveling is not even. In this paper, we propose CB-MG (Cost Benefit between Multi Group) algorithm in which hot data are allocated in one group and cold data in another group, and in which role of hot group and cold group is exchanged every period. Experimental results show that performance and wear-leveling of CB-MG provide better results than those of CB-S.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.4
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• pp.300-306
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• 2021

Due to the development of IT technology, hardware technologies applied to IoT equipment have recently been developed, so smart systems using low-cost, high-performance RF and computing devices are being developed. However, in the infrastructure environment where a large amount of IoT devices are installed, big data collection causes a load on the collection server due to a bottleneck between the transmitted data. As a result, data transmitted to the data collection server causes packet loss and reduced data throughput. Therefore, there is a need for an efficient big data collection technique in an infrastructure environment where a large amount of IoT devices are installed. Therefore, in this paper, we propose an efficient big data collection technique in an infrastructure environment where a vast amount of IoT devices are installed. As a result of the performance evaluation, the packet loss and data throughput of the proposed technique are completed without loss of the transmitted file. In the future, the system needs to be implemented based on this design.

• The KIPS Transactions:PartB
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• v.9B no.5
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• pp.533-540
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• 2002

We can buy products everywhere from Web-based shopping mall using desktop, cellular phone or PDA. To guarantee the various services for different equipment, shopping mail systems should allow a lot of different size or quality of images to provide a good service to their customers. Despite of same product image, each shopping mall saves the image in its storage space individually. Furthermore, all the product images in each shopping mall are stored as images of different quality. It may waste resources of shopping mail server and bring us developmental overhead. It is difficult to update all the images for product that is used by distributed e-catalog in everywhere. In this paper, we extended the proposed Web Image Server (WIS) for sharing one image with all clients and processing Image dynamically, so that we strengthened the function of managing shopping mall as a client of WIS and added the function of recording clients'log file and image catalog for shopping mall. We measured the response time from WIS and conventional e-Commerce site using by WAS which is one of the stress test tools for Web application. Furthermore, we measured WIS responses image requests in reasonable time when the current user is increased.