• Journal of Communications and Networks
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• v.13 no.5
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• pp.494-498
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• 2011

Satellite digital multimedia broadcasting (S-DMB) systems use gap fillers (GFs) to provide wireless multimedia services to non-line-of-sight locations. GFs act as repeaters, and S-DMB systems require GF networks in order to guarantee mobile reception. Each GF covers a cell or sector. In order to provide contiguous coverage of an area comprising two or more cells or sectors, multiple GFs are needed. However, when multiple GFs are situated close to each other, interference is likely to occur. As a result, in this study, we have investigated system-level environments for planning the design of interference-free GF networks in S-DMB systems. Our investigations revealed that S-DMB services are unavailable because of quality deterioration caused by interference when the delay attributable to a GF and the satellite signals exceeds ${\pm}$256 chips and the distance between the GF and its reception terminal is greater than 4.6 km. On the basis of this analysis, we conducted a field test that confirmed that the above-mentioned time delay can be controlled in such a way as to ensure high quality S-DMB services.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.37-43
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• 2023

Compressed still image or video bitstreams require protection from channel errors in a wireless channel. Embedded Zerotree Coding(EZW), SPIHT could have provided unprecedented high performance in image compression with low complexity. If bit error is generated by dint of wireless channel transmission problem, the loss of synchronization on between encoder and decoder causes serious performance degradation. But wavelet zerotree coding algorithms are producing variable-length codewords, extremely sensitive to bit errors. The idea is to partition the lifting coefficients. A many partition of lifting transform coefficients distributes channel error from wireless channel to each partition. Therefore synchronization problem that caused quality deterioration in still image and video stream was improved.

• International journal of advanced smart convergence
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• v.4 no.2
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• pp.1-5
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• 2015

The necessity to distribute energy wirelessly has been spurred by the tremendous growth in the use of portable devices. Mobile devices have become ubiquitous and the circuits within them have been optimized to consume extremely low amounts of power. Such portable electronic sets are in constant use and the frequent need to recharge them; using conventional wired mechanisms have hindered the mobility of users. Wireless transmission of energy to power-up devices has been proposed since the days of Tesla and since then many theories and methods have been invented. This paper discusses some of those techniques briefly.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.173-181
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• 2023

Data collection is an essential element in the construction and operation of a smart factory. The quality of data collection is greatly influenced by network conditions, and existing wireless network systems for IoT inevitably lose data due to wireless signal strength. This data loss has contributed to increased system instability due to misinformation based on incorrect data. In this study, I designed a distributed MQTT IoT smart sensor and gateway structure that supports wireless multicasting for smooth sensor data collection. Through this, it was possible to derive significant results in the service latency and data loss rate of packets even in a wireless environment, unlike the MQTT QoS-based system. Therefore, through this study, it will be possible to implement a data collection management system optimized for the domestic smart factory manufacturing environment that can prevent data loss and delay due to abnormal data generation and minimize the input of management personnel.

• International journal of advanced smart convergence
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• v.13 no.1
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• pp.12-22
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• 2024

Software applications have a huge and inseparable impact on our lives. The complexity of the applications increases rapidly to support high performance and multifunction. Accordingly, the cost model for applications is increasingly important. Line of Code (LOC) and Man-Month (M/M) as the cost model measure the quantitative sides of the applications. Unlike them, Function Point (FP) measures the functionalities of the application. FP is efficient for estimating qualitative characteristics, but it is restricted to measuring the cost of an application using the wireless data broadcast which can support any number of clients. In this paper, we propose, a Function Point model for Information services using wireles data Broadcast (FPIB) to measure the development cost of an application that serves using the wireless data broadcast environment. FPIB adopts critical parameters of the wireless broadcast environment and the complexity of them to measure effectively the cost developing the application. Through the evaluation comparing the proposed FPIB with FP, we reveal the effectiveness of the proposed FPIB.

• Journal of Korea Spatial Information System Society
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• v.5 no.1 s.9
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• pp.75-81
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• 2003

In spite of widely deploying information broadcasting services based on Internet, there are some limitations to use them due to the bound of Internet protocol. In this paper, a new Internet broadcasting technology for access network and Location Based Services are proposed by employing IP address translation function in base station. There are some advantages such as, no need to allocate IP address to receiver no need to know web site address, and reduction of traffic for server and network.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.397-398
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• 2007

Currently, most of Passenger Service System is supported to VOD in Korea. This current PSS has not internet access, real time broadcasting system and entertainment. The system did not come up to the expectation of consumer. This paper presents an application of new Passenger Service System for developing multimedia as well as wireless communication technology on internet, satellite broadcasting.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.65-71
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• 2009

As a core area of the new computing paradigm, the Ubiquitous Sensor Network Technology utilizes a wireless sensor networking which can be applied to the Context Information Monitoring System. When the technology is used in a poor user-environment for monitoring purposes, it can cost-effectively gather the context data on real-time basis, analyze the information gathered, effectively response to the user situation, and execute orders to create environmental factors desired by the user. This study structures a system able to monitor information in regards to a user-environment based on wireless-node sensor technology coupled with the Ubiquitous Sensor Network Technology. In this paper, the protocol in which it manages the wireless sensor network as the zone based by using the management protocol standardized at the smart home with a profile is proposed. The proposed system requires a minimal collection of data without continuous monitoring. Monitoring periodically, it can sense the user-environment more efficiently than the existing monitoring technologies based on the wire-communication technology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.73-78
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• 2009

We researched economic efficiency and possibility of game portal service based PDA/Smart phone by popularize of next generation portable internet WiBro. PDA/Smart phone are difficult to equal level content service with PC, because of it has low CPU and memory than PC. This paper are implemented paper of integrated server of Cable or Wireless for WiBro contents. In this research, we implemented and show test result of CP killer contents in PDA. It can apply to WiBro portable internet and has required many functions in integrated server for cable or wireless. CP Killer contents for WiBro portable internet is developed by PC server base on Window XP. It can accept next generation wireless LAN, portable internet and ubiquitous issues. We expect activation of commercial use that WiBro contents and server trading.

• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.343-350
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• 2010

Wireless Sensor Network is an event-driven system that a large number of micro sensor nodes are collected, giving and Wing information. Congestion can take place easily since a great number of sensor nodes are sensing data and transferring them to sink nodes when an event occurs, comparing to the existing wired network. Current internet transport protocol is TCP/UDP, however, this is not proper for wireless sensor network event-driven ESRT, STCP and CODA are being studied for reliable data transport in the wireless sensor network. Congestion are being detected local buffer and channel loading with these techniques. Broadcasting is mainly used and can avoid congestion when one happens. The way that combining local buffer and channel loading information and detecting congestion is being studied in this paper. When congestion occurs, buffering state is divided into three in order to lessen the broadcasting sending the message on congestion control to the node having frequent channel loading. Thus they have advantage of decreasing network's loading.