• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2283-2291
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• 1999

Most of collaborative applications use the Server-Client paradigm where all requests of clients will be delivered first to server and that server distributes again the requests to the rest of clients. This server-oriented operation and data transmission mechanism always presents end-to-end communications between the server and clients that can notably decrease the overall performance of applications. In this paper, we propose a new design approach to inhibit the inefficiency of applications using active networking concepts. We propose the ASM service that offers an application-specific in-network multicast functions, the AMTC service and its tree algorithm that builds anon-core based shared tree for multicast. These proposed services locate in active nodes performing its services as part of the overall system to improve the performance of collaborative applications.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.255-266
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• 2022

Messenger applications applied end-to-end encryption on their own to prevent message exposure to servers. Standardization of a group messaging protocol called Message Layer Security (MLS) with end-to-end encryption is being discussed for secure and efficient message communication. This paper performs safety checks based on the operation process and security requirements of MLS. Confidentiality to a middleman server, which is an essential security requirement in messenger communication, can be easily violated by a server administrator. We define a server administrator who is curious about the group's communication content as a curious admin and present an attack in which the admin obtains a group key from MLS. Reminds messenger application users that the server can view your communication content at any time. We discuss ways to authenticate between users without going through the server to prevent curious admin attacks.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.4
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• pp.159-164
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• 2023

Solar energy harvesting IoT devices prioritize maximizing the utilization of collected energy due to the periodic recharging nature of solar energy, rather than minimizing energy consumption. Meanwhile, research on edge AI, which performs machine learning near the data source instead of the cloud, is actively conducted for reasons such as data confidentiality and privacy, response time, and cost. One such research area involves performing various audio AI applications using audio data collected from multiple IoT devices in an IoT edge computing environment. However, in most studies, IoT devices only perform sensing data transmission to the edge server, and all processes, including data preprocessing, are performed on the edge server. In this case, it not only leads to overload issues on the edge server but also causes network congestion by transmitting unnecessary data for learning. On the other way, if data preprocessing is delegated to each IoT device to address this issue, it leads to another problem of increased blackout time due to energy shortages in the devices. In this paper, we aim to alleviate the problem of increased blackout time in devices while mitigating issues in server-centric edge AI environments by determining where the data preprocessed based on the energy state of each IoT device. In the proposed method, IoT devices only perform the preprocessing process, which includes sound discrimination and noise removal, and transmit to the server if there is more energy available than the energy threshold required for the basic operation of the device.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.327-333
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• 2013

In this paper, we propose a QoS information collection method at the information server in maritime networks with multi-network interfaces, and a route selection scheme based of the measured predictive QoS information comparing with parameters requested from a mobile node in a ship entering into a harbor from near-shore area. By changing network conditions and applying various application bandwidths, we check the operation of our proposed scheme and measure its performance of the original and proposed schemes in the viewpoints of the received packet traffic and end-to-end delays.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.429-432
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• 2002

The existing recovery technique using the logging technique in the client/sewer database system only administers the log as a whole in a server. This contains the logging record transmission cost on the transaction that is executed in each client potentially and increases network traffic. In this paper, the logging technique for redo-only log is suggested, which removes the redundant before-image and supports the client-based logging to eliminate the transmission cost of the logging record. Also, in case of a client crash, redo recovery through a backward client analysis log is performed in a self-recovering way. In case of a server crash, the after-image of the pages which needs recovery through simultaneous backward analysis log is only transmitted and redo recovery is done through the received after-image and backward analysis log. Also, we select the comparing model to estimate the performance about the proposed recovery technique. And we analyzed the redo and recovery time about the change of the number of client and the rate of updating operation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.452-458
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• 2002

Although the reuse of the cached data for scrolling the map reduces the amount of passed data between client and server, it needs the conversions of data coordinates, selertive deletion of objects and cache compaction at client. The conversion is time intensive operation due to limited resources of mobile phones such as low computing power, small memory. Therefore, for the efficient map control in the vector map service based mobile phone, it is necessary to study the method for reducing wireless network bandwidth and for overwhelming the limited resources of mobile phone as well. This paper proposes the methods for racking pre-received spatial objects in client-server systems for mobile CIS. We also analyze the strengths and drawbacks between the reuse of cached data and transmission of raw data respectively.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.2
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• pp.75-86
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• 2017

Docker, which is one of the various virtualization technology in server systems, is getting popular as it provides more lightweight environment for service operation than existing virtualization technology. It supports easy way of establishment, update, and migration of server environment with the help of image and container concept. As the adoption of docker technology increases, the attack motive for the server for the distribution of docker images and the incident case of attacking docker-based hosts would also increase. Therefore, the method and procedure of digital forensic investigation of docker-based host including the way to extract the filesystem of containers when docker daemon is inactive are presented in this paper.

• Journal of the Korea Computer Industry Society
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• v.3 no.2
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• pp.227-234
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• 2002

An cluster web server system, one has the problem that does the low availability occured by the high chance of the server failures and it is not easy to provide high performance and availability occuring software aging. In this paper, running cluster web sewers consists of n primary servers and k backup servers, propose software rejuvenation model on performance and switchover time. Based on the various system operational parameters, we calculate to evaluate the rejuvenation policy such steady-state probabilities, availability, and downtime cost. And we validate the solutions of mathematical model by experiments based on various operation parameters and fud that the software rejuvenation method can be adopted as prventive fault tolerant technique for stability of system.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.419-425
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• 2012

In these days, the trends of home networking system is implementation of easily configured system with home security of emergency alarm and visitor verification services. In this paper, we implemented push server system based on Arduino of open source physical computation platform to verify visitors for the homes without home networking services. In the suggested system, visitor verification is performed in and out of home, and home access security of the system could be constructed with low-cost price by use of windows push server system and smart devices with alarm operation in corresponding to not allowed access trying.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.201-204
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• 2002

Although the reuse of the cached data for scrolling the map reduces the amount of passed data between client and server, it needs the conversions of data coordinates, selective deletion of objects and cache compaction at client. The conversion is time intensive operation due to limited resources of mobile phones such as low computing power, small memory. Therefore, for the efficient map control in the vector map service based mobile phone, it is necessary to study the method for reducing wireless network bandwidth and for overwhelming the limited resources of mobile phone as well. This paper proposes the methods for caching pre-received spatial objects in client-server systems for mobile GIS. We also analyze the strengths and drawbacks between the reuse of cached data and transmission of raw data respectively.