• Journal of KIISE:Computing Practices and Letters
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• v.6 no.1
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• pp.21-35
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• 2000

MIDAS-II is the storage system for BADA DBMS developed at ETRI. This paper describes the extension of MIDAS-II for incorporating the tertiary storage device such as an optical disk jukebox or a tape library, enabling MIDAS-II to function as a storage system of the data server that stores a massive amount of multimedia data. The MIDAS-II disk volume structure is extended to efficiently function as a volume for the tertiary storage device with multiple platters, which canstore huge amount of data of the order of tera bytes. The storage structure of the LOB is changed to efficiently manage the LOB data in the tertiary storage device. The data structures of the shared memory, the process structure, and the utilities in MIDAS-II are also extended to efficiently incorporating the tertiary storage device. The functionalities of each MIDAS-II API function are expanded to handle the tertiary storage device, while the prototypes of those functions are intact in order not to affect the existing application programs. The performance evaluation shows that the extended MIDAS-II works effectively with the tertiary storage device. All these extensions and the performance evaluation are conducted in the SunOS 5.4 environment.

• Journal of Korea Multimedia Society
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• v.5 no.1
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• pp.1-9
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• 2002

Video server which stores video streams should serve more users with the requested streams rapidly, satisfying their time constraints. In this paper, we propose the storage system that does not only maintain fast responses but also increase the number of users supported, with satisfying the time constraints characteristics of the video streams. When the video streams are retrieved in storage system under multiple disks environments, it can not only maintain the rapid responses but also can save the disk bandwidth owing to the retrieval based on priority. Also, it utilizes the given buffer capacity efficiently owing to determining the stream segment size heuristically, which is adapted to the buffer capacity Consequentially, these policies can increase the number of users supported. The correctness of the proposed policies is not only analyzed theoretically but also evaluated through simulations.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.22 no.6
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• pp.518-526
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• 2019

Purpose: Limited means exist to assess gastrointestinal activity in pediatric patients postoperatively. Recently, myoelectric gastrointestinal activity recorded by cutaneous patches has been shown in adult patients to be predictive of clinical return of gastrointestinal function postoperatively. The aim of this case series is to demonstrate the feasibility of this system in pediatric patients and to correlate myoelectric signals with return of bowel function clinically. Methods: Pediatric patients undergoing abdominal surgery were recruited to have wireless patches placed on the abdomen within two hours postoperatively. Myoelectric data were transmitted wirelessly to a mobile device with a user-interface and forwarded to a cloud server where processing algorithms identified episodes of motor activity, quantified their parameters and nominally assigned them to specific gastrointestinal organs based on their frequencies. Results: Three patients (ages 5 months, 4 year, 16 year) were recruited for this study. Multiple patches were placed on the older subjects, while the youngest had a single patch due to space limitations. Rhythmic signals of the stomach, small intestine, and colon could be identified in all three subjects. Patients showed gradual increase in myoelectric intestinal and colonic activity leading up to the first recorded bowel movement. Conclusion: Measuring myoelectric intestinal activity continuously using a wireless patch system is feasible in a wide age range of pediatric patients. The increase in activity over time correlated well with the patients' return of bowel function. More studies are planned to determine if this technology can predict return of bowel function or differentiate between physiologic ileus and pathologic conditions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.302-305
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• 2009

The Multiple vital signs management system using Mobil phone is designed with Wireless sensor network and CDMA which are integrated to create a wide coverage to support various environments like inside and outside of hospital. Health signals from medical sensor node are analysed in cell phone first for real time signal analyses and then the abnormal vital signs are sent and save to hospital server for detail signal processing and doctor's diagnosis. We developed integrated vital access processor of sensor node to use selective medical interface(ECG, Blood pressure and sugar module) and control the self-organizing network of sensor nodes in a wireless sensor network. chronic disease such as heart disease and diabetes is able to check using graph view in mobile phone.

• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.147-154
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• 2006

Effective and efficient representation of color features of multiple video frames is an important vet challenging task for visual information management systems. This paper Proposes a Video Browsing Service(VBS) that provides both the video content retrieval and the video browsing by the real-time user interface on Web. For the scene segmentation and key frame extraction of video sequence, we proposes an efficient scene change detection method that combine the RGB color histogram with the X2 (Chi Square) histogram. Resulting key frames are linked by both physical and logical indexing. This system involves the video editing and retrieval function of a VCR's. Three elements that are the date, the need and the subject are used for video browsing. A Video Browsing Service is implemented with MySQL, PHP and JMF under Apache Web Server.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.74-84
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• 2001

In the current Internet, InteServ model based on Resource reSerVation Protocol (RSVP), DiffServ Model based on service differentiation according to per hope behavior(PHB) and traffic engineering policy, and two-tire model of above mentioned two models which are adapted differently as the target network status for providing the end-to-end QoS Path are suggested. But, when we integrated this internet QoS into the ATM based network, differences of the connection setup procedure, name/address translation methods, and QoS provisioning mechanisms for end-to-end path setup procedures are introduced. In this paper, we propose the method of shortcut based QoS path setup procedure to solve these problems, and to guarantee the integration and scalability of Next Generation Internet(NGI) names/address in Integrated IP network into ATM based network. This network should support the engineering differentiated into the multiple service classes, which depend on established by this path is designed suitably into the target router and host step by step. In the near future, this function which provide the QoS guaranteed path based on end-to-end shortcut between the configuration devices are extended into the NGI target network.

• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.35-43
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• 2013

This paper suggests a way to implement a system that broadcasts compressed JPEG images obtained from a webcam to multiple users on their smartphones. The system was implemented to maintain a suitable image quality so that things are identifiable while using the minimal amount of data, in order to deliver as many frames as possible to as many users as possible. Also, the suggested way was applied and various tests were done, including on: the performance of the server that provides image information; the performance of the client that receives the image information and displays it on the smartphone; and the max. number of simultaneous users supported by the system. When a broadcasting system is implemented using webcams and smartphones, the results of this paper can be used in estimating the suitable system parameters depending on network performance, including the max. number of simultaneous clients supported, the client smartphone performance required, and the number of frames that can be transmitted per second.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.987-999
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• 2021

Recently, Federated learning has become an issue due to privacy invasion caused by data. Federated learning is safe from privacy violations because it does not need to be collected into a server and does not require learning data. As a result, studies on application methods for utilizing distributed devices and data are underway. However, Federated learning is no longer safe as research on the reconstruction attack to restore learning data from gradients transmitted in the Federated learning process progresses. This paper is to verify numerically and visually how well data reconstruction attacks work in various data situations. Considering that the attacker does not know how the data is constructed, divide the data with the class from when only one data exists to when multiple data are distributed within the class, and use MNIST data as an evaluation index that is MSE, LOSS, PSNR, and SSIM. The fact is that the more classes and data, the higher MSE, LOSS, and PSNR and SSIM are, the lower the reconstruction performance, but sufficient privacy invasion is possible with several reconstructed images.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.99-104
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• 2021

Blockchain technology is a distributed ledger technology that shares the ledger between multiple nodes connected to a distributed network. The data managed through the existing central server is managed through the blockchain, and the transparency, accuracy, and integrity of the transaction data is increased, and the need for data management through the blockchain is increasing. In this paper, recognizing the need for trust-based data sharing between trust-based institutions in the financial industry, this paper describes the process of selecting leader nodes in Raft, a private blockchain consensus algorithm, as a way to increase data management efficiency through blockchain. A modified consensus algorithm is presented. The performance of the modified consensus algorithm and the general Raft consensus algorithm presented in this paper was compared and analyzed based on the transaction processing time, and it was confirmed that the efficiency of the consensus process was increased by applying the proposed consensus algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.91-97
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• 2021

A microserver is a type of a computing server, in which two or more CPU nodes are implemented on a separate computing board, and a plurality of computing boards are integrated on a main board. In building a cluster system, the microserver has advantages in several points such as energy efficiency, area occupied, and ease of management compared to the existing method of mounting legacy servers in multiple racks. In addition, since the microserver uses a fast interconnection network between CPU nodes, performance improvement for data transfers is expected. The proposed microserver can mount a total of 16 computing boards with 4 CPU nodes on the main board, and uses Serial-RapidIO (SRIO) as an interconnection network. In order to analyze the performance of the proposed microserver in terms of the interconnection network which is a core performance issue of the microserver, we compare and quantify the performance of commercial microservers. As a result of the test, it showed up to about 7 times higher bandwidth improvement when transmitting data using the interconnection network. In addition, with CloudSuite benchmark programs used in actual cloud computing, maximum 60% reduction in execution time was obtained compared to commercial microservers with similar CPU performance specification.