Yong-Tae Lee

The physicochemical properties of polyindole / thiol composites

We synthesized the polyindole (PI) and poly(2,5-dimercapto-1,3,4-thiadiazole) (pDMcT) by chemical oxidation method. The polymerization of PI and pDMcT was confirmed by FT-IR. We have measured the electrochemical properties of the unit cell both before and after charge/discharge experiment. It showed the plateau region around 3.0V in discharge curves behavior. The specific discharge capacity value of these compositions was saturated after 10th cycle as ∼75mAh/g. We have tried to explain the reaction in PI/thiol composites with various methods. The intensity of the ESR signal increases after charging and the σ dc of these composites increases by charging. From the results, it could be found that the formation of unpaired electrons at nitrogen site in PI is confirmed in this system.

Development of T-DMB emergency broadcasting system and trial service with the legacy receivers

The emergency broadcasting system based on T-DMB network have been developed and installed in tunnel environment. This paper describes implementation and field test results of the T-DMB emergency broadcasting system in practical tunnel environment. The developed emergency broadcasting system can execute the on-channel repeating function in common environment. And the system provides emergency broadcasting service in accident or disaster environment to legacy T-DMB receivers. According to the field test results, the smooth operation is evaluated for both emergency broadcasting function and on-channel repeating function with legacy T-DMB receivers.

Modulation and Pre-Equalization Method to Minimize Time Delay in Equalization Digital On-Channel Repeater

This paper presents novel modulation and pre-equalization methods to minimize a signal processing time delay in the equalization digital on-channel repeater (EDOCR) for the ATSC terrestrial digital TV system. The proposed modulation method uses equi-ripple (ER) filter for vestigial side bands (VSB) pulse shaping instead of conventional square root raised cosine (SRRC) filter. And the proposed pre-equalization method calculates pre-equalizer filter coefficients by comparing a baseband signal as a reference signal and a demodulated repeater output signal, and then creates new VSB pulse shaping filter coefficients by the convolution of the ER filter and the pre-equalizer filter coefficients. The new VSB pulse shaping filter minimizes the time delay of EDOCR by adjusting the number of its pre-taps and also compensates the linear distortions due to the use of the ER filter and mask filter.

An efficient emergency broadcasting signal multiplexing method for supporting the legacy T-DMB receivers in break-in system

In this paper, design and implementation of T-DMB emergency broadcasting system (EBS) are introduced. Especially, to reduce the T-DMB EBS implementation cost, efficient encoding and multiplexing schemes are proposed and adopted to the system. Since proposed encoding and multiplexing technologies can reduce the number of encoders and multiplexers, the T-DMB EBS with proposed techniques are efficiently built. The performance of the T-DMB EBS has been evaluated by laboratory and field tests with various commercial receivers, satisfactory results have been drew1.

An implementation of energy-saving set-top box

This paper introduces an implementation example of a digital TV set-top box which has energy-saving capability. This energy-saving set-top box supports four types of power states: active on, active standby, deep-sleep passive standby, and off. Particularly, in the deep-sleep passive standby state, the level of power consumption of the set-top box goes down to less than 1 watt. And the set-top box can wake up from the deep-sleep passive standby state to go back to the active on state in less than 10 seconds.

Standby mode control based on network assistance for power saving of a set-top box

In this paper, standby mode control for set-top boxes based on network assistance is proposed. A set-top box with the standby mode control uses network-assisted passive standby mode that allows a set-top box to access network access during standby state where a set-top box does not receive broadcast services. The standby mode control helps a set-top box to update its software and firmware in standby state and save power consumption in standby state compared to a previous mechanism.

Activation pattern based standby mode scheduling for power-efficient set-top box

In this paper, activation pattern based standby mode scheduling is proposed for reducing power consumption of a set-top box during standby state where a set-top box does not receive broadcast services. The set-top box with the standby mode scheduling finds mainly used time (i.e., when users mainly uses the set-top box) and seldom used time by analyzing record of its activation pattern. The set-top box saves power consumption by scheduling passive standby mode (i.e., the lowest power mode) during seldom used time, and reduces time for activating by scheduling active standby mode during mainly used time.

A signaling emergency alert system multiplexed with T-DMB channel for emergency alert service

Mobile broadcasting services are considered effective methods for emergency alert delivery. Terrestrial digital multimedia broadcasting (T-DMB) offers an emergency alert service called automatic emergency alert service (AEAS). However, the conventional AEAS is inefficient in the aspects of alert service channel, disabled T-DMB receiver, and location-based service. Therefore, this paper proposes a novel signaling method in order to overcome the drawbacks of the AEAS. The presented alert system exploits an additional alert channel, which is multiplexed with the conventional T-DMB channel. This paper also addresses the multiplexing approach, which effectively eliminates the interference between the additional alert channel and the TDMB channel. The simulation results confirm that the proposed signaling method effectively offers the emergency alert services in T-DMB1.

Compatibility analysis of in-band digital radio systems in interference channel environment

Many countries today face converting their analog radio broadcasting to digital service. Since the in-band digital radio systems are used in the existing analog FM frequency band, compatibility and robustness is very important characteristics of the digital radio systems. In this paper, we evaluate the performances of HD-Radio and DRM+ which are in-band digital radio broadcasting techniques in the various interference channel environment. These results are able to give basic information for the decision of digital radio standard in many countries.

An implementation of PC state management in IP networks

In this paper, an implementation of remote waking-up Personal Computers (PCs) through UDP and Wake On LAN (WOL) is presented. With the implementation, PCs can be sus pende d w hile it is in idle time. Also, PCs can be waked up interactively from remote site when users want to perform required tasks. There is a few barriers to wake a PC up from remote site using WOL. By providing a solution for the barriers, PCs can be in low power states while required tasks can be performed as necessary after the wakeup. Proposed implementation can be applied to IT devices that have similar architecture and communication interface to PCs.