• Journal of Korea Multimedia Society
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• v.10 no.6
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• pp.707-715
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• 2007

The need for content-based retrieval from visual media, such as image and video data, is ever increasing rapidly in many applications, such as electronic art museums, internet shopping malls, internet search engines, and medical information systems. In our previous research, we proposed an architecture, called the HERMES, which is a Web Service-enabled visual media retrieval framework. In this paper, we propose the Web Service workflows that are employed in the HERMES. We describe how we designed the workflows for service registration and query processing in the framework. We especially explain how metadata and ontology can be utilized to realize more intelligent content-based retrieval on visual media data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.468-479
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• 2012

Recent advances in wireless communications and electronics has enabled the development of machine-to-machine (M2M) communications. This communication paradigm has been expected as an automated control and report solution for smart grid. The smart grid enables customers and operators to utilize the collected usage information from a large number of meters with transceivers for efficiency and safety. In this paper, we introduce architecture, requirements and challenges of M2M communications for smart grid. We extract technical issues that should be resolved in M2M communications to support the smart grid via third-generation partnership project (3GPP) cellular networks. We then present the current state of the art of research results to deal with such issues. Finally, we outline the open research issues.

• International Journal of Internet, Broadcasting and Communication
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• v.8 no.1
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• pp.27-32
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• 2016

The global positioning system (GPS)-enabled mobile phones provide location-based applications such as car and pedestrian navigation services. The pedestrian navigation services provide safe and comfortable route and path guidance for pedestrians and handicapped or elderly people. One of the essential components for a navigation system is a spatial database used to perform navigation and routing functions. In this paper, we develop modeling and categorization of pedestrian path components for smart tour guide services using the mobile pedestrian navigation application. We create pedestrian networks using 2D base map and sky view map in urban area. We also construct pedestrian networks and attributes of node, link, and POI using on-site GPS data and photos for smart pedestrian tour guide in the major walking tourist spots in Jeju.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.273-277
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• 2021

As society gradually enters a virtual, non-face-to-face society, the use of online content is increasing as well. In particular, as smartphones are thoroughly established in our daily life, the platforms of webtoons, mobile broadcasting, and education are shifting from personal computers to smartphones. Recently, the development of the Over-The-Top media service (OTT service) enabled streaming services of various media contents through the internet and activation of IPTV. Therefore, the rapid increase of popularity of short-form content is a natural phenomenon with smartphone platforms with fast, improvised, and endless communication. Lately, TikTok became the favored platform with prosumers, defined as people who are both producers and consumers. In this study, I studied the experiential response of YouTube and TikTok users as representative examples of a short-form content platform developed after the 2000s, the flourishing years of digital content with a length of 30 seconds.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.1-7
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• 2023

TCP is considered a major candidate transport protocol even for constrained IoT networks due to its ability to integrate into the existing network infrastructures. Since TCP implementations such as uIP TCP often allow only a single TCP segment per connection to be unacknowledged at any given time due to resource constraints, the congestion control relies only on RTO management. In our previous work, to address the problem that uIP TCP performs poorly particularly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe, we proposed a RTO scheme for uIP TCP and validated the performance through Cooja simulation. In this study, we investigate the effect of other factors that were not considered in our previous work. More specifically, the effect of traffic intensity, the degree of the hidden terminal problem, and RDC is investigated by varying the offered load and the transmission range, and the RDC channel check rate. Simulation results imply that we need to further investigate how to improve TCP performance when the radio duty cycling mechanism is used.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.29-35
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• 2024

TCP is considered as one of the major candidate transport protocols even for constrained IoT networks..In our previous work, we investigated the congestion control mechanism of the uIP TCP. Since the uIP TCP sets the window size to one segment by default, managing the retransmission timer is the primary approach to congestion control. However, the original uIP TCP sets the retransmission timer based on the fixed RTO, it performs poorly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe. In our previous work, we proposed a TCP retransmission timer adjustment scheme for uIP TCP which adopts the notion of weak RTT estimation of CoCoA, exponential backoffs with variable limits, and dithering. Although our previous work showed that the proposed retransmission timer adjustment scheme can improve performance, we observe that the scheme often causes a node to set the retransmission timer for an excessively too long time period. In this work, we show that slightly modifying the dithering mechanism of the previous scheme is effective for improving TCP fairness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.3904-3917
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• 2017

IP multimedia subsystem (IMS) is an open standardized architecture for delivering multimedia service over IP network in a route-agnostic manner. With the increasing popularity of conversational class service, the delivery of a traffic flow with a certain bandwidth demand over a single network path is either not possible or not cost-effective. Multipath transmission is considered to be a promising solution to provide high-quality delivery service. This paper proposes a software defined service overlay network (SDSON) based multipath transmission framework for IMS, which is complementary to existing network architecture. The framework transforms original two-party session negotiation into three-party session negotiation that supports participants to negotiate multipath transmission capacity and path information by signaling message. Based on existing IETF standards, SIP and SDP are scalable to support these functions. Finally, the proposed framework is fully implemented on open source platform and examined by experiments. Experimental results show that multipath-enabled IMS is an effective way to improve the delivery performance of conversational class service.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.6
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• pp.83-99
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• 2011

OTP (One Time Password) is widely used for protecting accounts on Internet banking, portal services and online game services in Korea. OTP is very strong method for enforcing account security but there are several ways for exploiting vulnerabilities caused by implementation errors. These attacks can work because of the weakness from OTP enabled system's vulnerabilities, not for OTP's algorithm itself. In this paper, we present the known attack scenarios such as MITM (Man-in-the-Middle) attack and various reverse engineering techniques; also, we show the test result of the attacks and countermeasures for these attacks.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.1
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• pp.65-71
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• 2012

This paper introduces computer based practice for engineering education through using NI-ELVIS and virtual instruments of LabVIEW as application software. Different laboratory experiments "Labs" will be presented as convenient paradigms of adopting computer based practice for the efficacy of engineering education. Remote labs as web/internet or network-enabled controlled by remote server computer have been extensively used by a number of universities, national laboratories and companies for different kind of application around the globe. Overtime, as technology proceed in its progress, more developed techniques are being used particularly in the field of engineering education.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2793-2803
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• 2013

In H.264, three different data partition types are used, which have unequal importance to the reconstructed video quality. To improve the performance of H.264 video streaming transmission over IEEE 802.11e Wireless Local Area Networks, a prioritization mechanism that categorizes different partition types to different priority classes according to the calculated distortion within one Group of Pictures. In the proposed scheme, video streams have been encoded based on the H.264 codec with its data partition enabled. The dynamic scheduling scheme based on Enhanced Distributed Channel Access has been configured to differentiate the data partitions according to their distortion impact and the queue utilization ratio. Simulation results show that the proposed scheme improves the received video quality by 1dB in PSNR compared with the existing Enhanced Distributed Channel Access static mapping scheme.