• Journal of Power Electronics
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• v.16 no.6
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• pp.2212-2220
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• 2016

Based on the conventional PID algorithm and the adaptive PID (AD-PID) algorithm, a separate sampling adaptive PID (SSA-PID) algorithm is proposed to improve the transient response of digitally controlled DC-DC converters. The SSA-PID algorithm, which can be divided into an oversampled adaptive P (AD-P) control and an adaptive ID (AD-ID) control, adopts a higher sampling frequency for AD-P control and a conventional sampling frequency for AD-ID control. In addition, it can also adaptively adjust the PID parameters (i.e. $K_p$, $K_i$ and $K_d$) based on the system state. Simulation results show that the proposed algorithm has better line transient and load transient responses than the conventional PID and AD-PID algorithms. Compared with the conventional PID and AD-PID algorithms, the experimental results based on a FPGA indicate that the recovery time of the SSA-PID algorithm is reduced by 80% and 67% separately, and that overshoot is decreased by 33% and 12% for a 700mA load step. Moreover, the SSA-PID algorithm can achieve zero overshoot during startup.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.681-688
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• 2016

Several VHF bands for the use in analog communications has been changed to those for the use in new maritime digital communications by WRC-12. ITU-R M. 1842-1 has been also standardized, recommending the characteristics of maritime digital communication systems. In addition, a Shipborne Ad-hoc Network (SANET) has been introduced by IMO in order to provide ships, which cannot be connected to a shore directly, with maritime digital data exchange services with the help of ad-hoc communication. In this paper, several functionalities of the SANET, including channel access, route determination to a shore, and data exchange, are verified via sea trials. It is expected that the SANET can be applicable to collecting and analyzing maritime information, facilitating the entry and departure of vessels, and the communication infrastructure of e-navigation.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.491-506
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• 2014

The purpose of this study is to examine the effect of expected perspective on the role of genre and attitude toward utilizing genre in broadcast ad on the liking of broadcast ad genre as appeal types of creativity. The results show that there is a significant correlation between macro-environmental expected perspective(MEEP) on the role of genre and a negative attitude toward utilizing genre in broadcast ad. A significant correlation between micro-practical expected perspective(MPEP) and a positive attitude was also found. Consumers with an integrated-situational expected perspective(ISEP) show a more significant relationship with the dual attitude. Consumes with a MPEP have a stronger liking on comparative ad and sex appeal ad, and consumers with an ISEP show a median liking. Consumers with positive attitude have a stronger liking on comparative ad and sex appeal ad, and consumers with a dual attitude show a median liking that is between the positive attitude-based consumers' and negative attitude-based consumers'.

• Journal of Digital Contents Society
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• v.19 no.1
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• pp.1-10
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• 2018

This study is to seek to find the importance of next digital marketing factors by using AHP method and analyze comparison between an advertising expert and a non-advertising expert. In results, the relative importance ranking is as follows; combination (0.26), transformation (0.259), optimization (0.243), and technology (0.238). The relative importance ranking of sub-factors is as follows: artificial intelligence and maching learning (0.086), big data (0.085), and contents curation (0.060). While the relative importance of combination and optimization for an advertising expert is higher than for non-advertising expert, the relative importance of transformation and technology for non-advertising is higher than for an advertising expert. This study provides managerial implication to build digital strategy based on these result.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2C
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• pp.167-172
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• 2008

Since a 2-dimensional (2D) bar code can retrieve data and information quickly, it is widely used and recognized as a useful tool for many industrial applications. However, the information capacity of the 2D bar code is still limited. Recently the analog-digital code (AD code), which has the largest storage capacity yet contained in a code, has been developed, thereby expanding the bar code's application range because it overcomes the limitation of data capacity. In this paper, we present the AD code and implement an effective embedded system which can transform text information into voice using the 2D AD code and Text To Speech (TTS). This voice information can also be transmitted to blind people as well as the old by capturing the AD code on paper or in books.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.2
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• pp.9-16
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• 2022

The nodes constituting the vehicle ad hoc network (VANET) are vehicles moving along the road and road side units (RSUs) installed around the road. The vehicle ad hoc network is used to collect the status, speed, and location information of vehicles driving on the road, and to communicate with vehicles, vehicles, and RSUs. Today, as the number of vehicles continues to increase, urban roads are suffering from traffic jams, which cause various problems such as time, fuel, and the environment. In this paper, we propose a method to solve traffic congestion problems on urban roads and demonstrate that the method can be applied to solve traffic congestion problems through performance evaluation using two typical protocols of vehicle ad hoc networks, AODV and GPSR. The performance evaluation used ns-2 simulator, and the average number of traffic jams and the waiting time due to the average traffic congestion were measured. Through this, we demonstrate that the vehicle ad hoc-based traffic congestion management technique proposed in this paper can be applied to urban roads in smart cities.

• Journal of Digital Contents Society
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• v.4 no.2
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• pp.203-210
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• 2003

In this paper we proposed a new MAC protocol to improve QoS(Quality of Service) for real-time traffic in wireless Ad Hoc networks. NMAC protocol have a contention period reservation scheme and a priority control scheme to provide fairness of nodes and QoS. Through simulation, the NMAC protocol compared with existing CSMA MAC protocols shows improvement in performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.22-28
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• 2008

This paper designed a efficient 8-bit CMOS analog-to-digital converter(ADC) for an SOC(System On Chip) application. The architecture consists of two modified 4-bit full-flash ADCs, it has been designed using a more efficient architecture. This is to predict roughly the range in which input signal residers and can be placed in the proximity of input signal based on initial prediction. The prediction of input signal is made available by introducing a voltage estimator. For 4-bit resolution, the modified full-flash ADC need only 6 comparators. So a 8-bit ADC require only 12 comparators and 32 resistors. The speed of this ADC is almost similar to conventional full-flash ADC, but the die area consumption is much less due to reduce numbers of comparators and registors. This architecture uses even fewer comparator than half-flash ADC. The circuits which are implemented in this paper is simulated with LT SPICE tool of computer.

• Journal of Digital Contents Society
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• v.19 no.7
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• pp.1303-1312
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• 2018

The study analyzed the evaluation of the advertisement effect by the score and the method of the advertisement comments in ad evaluation in online site, 'TVCF'. The results are as follows. First, Internet viral advertisement showed higher number of ad comments and higher evaluation of advertisement effect than cable broadcasting advertisement. Second, the results of analysis of the difference of advertisement evaluation according to ad types and digital user characteristics showed that women are more positive than men toward both cable broadcasting and internet viral advertisement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.1
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• pp.52-83
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• 2009

In this technical report, we have examined the basic building blocks of mobile ad-hoc networks. The paper discusses various security requirements of ad-hoc networks, attacks in ad-hoc networks, Security Implementation and Routing Protocols. The primary purpose of the paper is to address the Optimized Link State Routing (OLSR) protocol in detail, along with the various possible attacks. Finally, algorithms for securing OLSR are proposed, via the addition of digital signatures, as well as more advanced techniques such as cross checking of advertised routing control data with the node's geographical position. The main aim of this research work is the addition of security features to the existing OLSR protocol. In order to effectively design a secure routing protocol, we present a detailed literature survey of existing protocols, along with the various attacks. Based on the information gathered from the literature survey, a secure routing protocol for OLSR is proposed. The proposed secure routing protocol involves the addition of a digital signature as well as more advanced techniques such as the reuse of previous topology information to validate the actual link state. Thus, the main objective of this work is to provide secure routing and secure data transmission.