• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.1
• /
• pp.157-164
• /
• 2012

This paper introduces an implementation of SVC player which runs on Android platform and can play SVC video stream on line from SVC video server. SVC(Scalable Video Coding) is a scalable video encoding technique which supports three scalability such as temporal scalability, spatial scalability, and quality scalability. To implement the SVC player on Android, we implemented a SVC decoder using JSVM open source written in C/C++ as a native part on Android and developed Android UI in Java. Also we built an SVC encoding system off line and an SVC streaming server to conduct on-line SVC streaming experiments. Finally, after we installed the SVC player developed in this paper on Motoroi mobile phone, we evaluated and analyzed on-line streaming performance of the SVC player. The result showed that the player worked well and it had no jitter in streaming with the size of QCIF and 10fps from a fully encoded SVC video source.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.4
• /
• pp.31-40
• /
• 2016

In vehicular ad-hoc networks (VANETs), vehicles sense information on emergency incidents (e.g., accidents, unexpected road conditions, etc.) and propagate this information to following vehicles and a server to share the information. However, this process of emergency message propagation is based on multiple broadcast messages and can lead to broadcast storms. To address this issue, in this work, we use a novel approach to detect the vehicles that are farthest away but within communication range of the transmitting vehicle. Specifically, we discuss a signal-to-noise ratio (SNR)-based linear back-off (SLB) scheme where vehicles implicitly detect their relative locations to the transmitter with respect to the SNR of the received packets. Once the relative locations are detected, nodes that are farther away will set a relatively shorter back-off to prioritize its forwarding process so that other vehicles can suppress their transmissions based on packet overhearing. We evaluate SLB using a realistic simulation environment which consists of a NS-3 VANET simulation environment, a software-based WiFi-IP gateway, and an ITS server operating on a separate machine. Comparisons with other broadcasting-based schemes indicate that SLB successfully propagates emergency messages with latencies and hop counts that is close to the experimental optimal while reducing the number of transmissions by as much as 1/20.

• Journal of Digital Convergence
• /
• v.20 no.3
• /
• pp.343-348
• /
• 2022

Recently, With the recent rapid development of technology, the amount of data generated by various systems is increasing, and enterprise servers and data centers that have to handle large amounts of big data need to apply high-stability and high-performance storage devices even if costs increase. In such systems, SSD(solid state disk) that provide high performance of read/write are often used as storage devices. However, due to the characteristics of reading and writing on a page-by-page basis, erasing operations on a block basis, and erassing-before-writing, there is a problem that performance is degraded when duplicate writes occur. Therefore, in order to delay this performance degradation problem, over-provision technology of SSD has been applied internally. However, since over-provided technologies have the disadvantage of consuming a lot of storage space instead of performance, the application of inefficient technologies above the right performance has a problem of over-costing. In this paper, we proposed a method of measuring the performance and cost incurred when various over-provisions are applied in an SSD and predicting the system-optimized over-provided ratio based on this. Through this research, we expect to find a trade-off with costs to meet the performance requirements in systems that process big data.

• Journal of Digital Convergence
• /
• v.18 no.5
• /
• pp.249-256
• /
• 2020

The session initiation protocol (SIP) is a signaling protocol, which is used to controlling communication session creation, manage and finish over Internet protocol. Based on it, we can implement various services like voice based electronic commerce or instant messaging. Recently, Qiu et al. proposed an enhanced password authentication scheme for SIP. However, this paper withdraws that Qiu et al.'s scheme is weak against the off-line password guessing attack and has denial of service problem. Addition to this, we propose an improved password authentication scheme as a remedy scheme of Qiu et al.'s scheme. For this, the proposed scheme does not use server's verifier and is based on elliptic curve cryptography. Security validation is provided based on a formal validation tool ProVerif. Security analysis shows that the improved authentication scheme is strong against various attacks over SIP.

• Journal of Korea Multimedia Society
• /
• v.9 no.10
• /
• pp.1322-1331
• /
• 2006

Concurrency control is one of the important factors to maintain consistent conditions of a game because most participants of the game should be shared information to play the game through a distributed network system. replay delay times should establish in every event and the received event should be saved and performed simultaneously for Concurrency Control. However, it is not easy to practice the event with same speed in environment having various moving speed. Therefore, expansion have to be provided. In other words, one of the most important factors of a game's efficiency is the process of bandwidth and delay. the process of concurrency control method based on scalable prediction for Multi-platform games would minimize the loss rate of a event and then would improve the interaction capacity of a game. It also might get reliability between clients. This paper analyzes some problems in terms of a layout of a game that integrates a cable and a wireless system. In addition, this paper provides methods to expand bandwidth and delay that might be an obstacle of a On-line game and to ensure reliability between a server and a client.

• Journal of Internet of Things and Convergence
• /
• v.2 no.2
• /
• pp.21-26
• /
• 2016

In this paper, it is possible to update the tourist information in real time, on/off-line tour proposes a solution(BBTS) based on a bluetooth beacon can provide tourist information without the need for wireless data network. BBTS consists of a bluetooth based data of the low-power supply system and the beacons and interoperable smart applications. Data supply system consists of the BLE & Beacon Pairing-based / non-pairing data transmission module with integral hardware. Smart application modules that provide indoor location of users information, internal server module and tourist information collection and information guide around comprised of applications. The proposed BBTS is possible that indoor service tourism tourist demand due to utilizing the beacon technology. Outdoor tourist information is designed to be downloaded to the smartphone receives the information received from the beacon APK file to provide services. BBTS system is expected to make a big impact on the smart tourism services industry.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.7B
• /
• pp.1211-1219
• /
• 1999

High quality real-time interactive multimedia services like VOD gained huge momentum by information technology industries during the middle of 1990, but failed successful commercial service deployment despite of the expectations. Among the number of reasons, lack of high bandwidth and QoS support from the network infrastructure have become main cause of the failure. On the other hand, the advance of computer industry-driven storage technologies has been reducing the price of in-home storage dramatically. This fact and the delivery of audio-visual material in a digital form to the home storage make very interesting multimedia service applications possible. It enables anytime content delivery (e.g., during off-peak time) without user interaction and anytime content play and, also, enhances utilization by reducing the loads applied to servers and networks using multicast network infrastructure. In this paper, we propose design and implementation of our anytime multimedia service system based on in-home storage, called IMPRESS-AMS.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.12
• /
• pp.1141-1153
• /
• 2010

This paper introduces ONLIS(Overlay Multicast Network for Live IPTV Service), a novel overlay multicast network optimized to deliver live broadcast IPTV stream. We analyzed IPTV reference model of ITU-T IPTV standardization group in terms of network and stream delivery from the source networks to the customer networks. Based on the analysis, we divide IPTV reference model into 3 networks; source network, core network and access network, ION(Infrastructure-based Overlay Multicast Network) is employed for the source and core networks and PON(P2P-based Overlay Multicast Network) is applied to the access networks. ION provides an efficient, reliable and stable stream distribution with very negligible delay while PON provides bandwidth efficient and cost effective streaming with a little tolerable delay. The most important challenge in live P2P streaming is to reduce end-to-end delay without sacrificing stream quality. Actually, there is always a trade-off between delay & stream quality in conventional live P2P streaming system. To solve this problem, we propose two approaches. Firstly, we propose DSPT(Distributed Streaming P2P Tree) which takes advantage of combinational overlay multicasting. In DSPT, a peer doesn't fully rely on SP(Supplying Peer) to get the live stream, but it cooperates with its local ANR(Access Network Relay) to reduce delay and improve stream quality. When RP detects bandwidth drop in SP, it immediately switches the connection from SP to ANR and continues to receive stream without any packet loss. DSPT uses distributed P2P streaming technique to let the peer share the stream to the extent of its available bandwidth. This means, if RP can't receive the whole stream from SP due to lack of SP's uploading bandwidth, then it receives only partial stream from SP and the rest from the ANR. The proposed distributed P2P streaming improves P2P networking efficiency.

• Journal of Korea Multimedia Society
• /
• v.14 no.2
• /
• pp.238-248
• /
• 2011

Various services through mobile have been expanding since the development of the Smartphones. People freely communicate, remake and redistribute the information through Wi-Fi. People's freedom can cause lots of problems. There are application licenses of various types in the Android platform. However, problems about redistribution are indiscriminately distributed what can't be disentangled commercial and noncommercial use. To solve these problems, an application program has to go through procedures of license check in the Android platform. This method has two problems. One, an exact license authentication is impossible in the place where Wi-Fi does not work. The other thing, this license information is stored directly into the Smartphone. Therefore, attacks are possible about the stored license information, To solve these problems, we designed and implemented the file structure for storing the license information into USIM. We can store and authenticate them. Thus, we propose above the authentication method that can be authenticated the license authentication safely in on or off-line.

• Journal of Digital Contents Society
• /
• v.16 no.2
• /
• pp.189-196
• /
• 2015

The proposed cooperative 3D modelling system enables more efficient modeling works by improving current cooperation systems. Current 3D modeling tasks work on off-line and most of works are cooperation systems which communicate by files. These cooperation system cannot be interactive, occurs time delay while feedback and must have some programs which can read the files. This paper solves these problems using web that has the characteristics of network and proposes new cooperation system form. Using WebGL(Web Graphics Library) which is proposing technology in technical realization of Web 3D modeling, we make 3D objects in web browser and these objects can be manipulated by server-client communication. Therefore, if people use this system, they can use real time interaction and feedback. Also this system lowers a software installation necessity and can access everytime if web browser is installed.