• Journal of Korea Multimedia Society
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• v.10 no.2
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• pp.246-259
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• 2007

The animation industry, which accelerates the overall development of the Digital contents industry, is a high value-added industry that produces synergy effects in cooperation with key industries such as IT. Effectively serving as a vital energy source for the Korean economy through its positive effects, such as employment creation. In particular, there is the real prospect that the Korean animation industry will gain ground in overseas markets and thus occupy them ahead of others, by advancing overseas in uni son with the hypersonic network industry. In this regard, this study aims to suggest some concrete ways in which to Korean animation companies can enhance their competitiveness. This is accomplished by positively verifying that some major representative methods of competitiveness enhancement, whose effectiveness has been proved in existing manufacturing and production systems. a re also excellently effective for the animation enterprise. In effect, the study has positively applied and carried out such research on Korean animation enterprises.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1037-1047
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• 2017

The Differential Power Processing (DPP) converter is a promising multi-module photovoltaic inverter architecture recently proposed for photovoltaic systems. In this paper, a DPP converter architecture, in which each PV-panel has its own DPP converter in shunt, performs distributed maximum power point tracking (DMPPT) control. It maintains a high energy conversion efficiency, even under partial shading conditions. The system architecture only deals with the power differences among the PV panels, which reduces the power capacity of the converters. Therefore, the DPP systems can easily overcome the conventional disadvantages of PCS such as centralized, string, and module integrated converter (MIC) topologies. Among the various types of the DPP systems, the feed-forward method has been selected for both its voltage balancing and power transfer to a modified H-bridge inverter that needs charge balancing of the input capacitors. The modified H-bridge multi-level inverter had some advantages such as a low part count and cost competitiveness when compared to conventional multi-level inverters. Therefore, it is frequently used in photovoltaic (PV) power conditioning system (PCS). However, its simplified switching network draws input current asymmetrically. Therefore, input capacitors in series suffer from a problem due to a charge imbalance. This paper validates the operating principle and feasibility of the proposed topology through the simulation and experimental results. They show that the input-capacitor voltages maintain the voltage balance with the PV MPPT control operating with a 140-W hardware prototype.

• Journal of KIISE:Information Networking
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• v.36 no.4
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• pp.322-329
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• 2009

Many researches in wireless sensor networks have used a geographic routing to effectively disseminate data between sinks and sources. To know the location information, the geographic routing has proposed two manners. A sink-initiated and a source-initiated are flooding to disseminate its location information in WSN. However, these two manners have two problems. Firstly, whenever they move, they flood their location information. Secondly, their location information is disseminated unnecessary nodes besides nodes which send and receive data in actually. Therefore, this paper proposes a protocol that can solve the two problems and disseminate effectively data between few sinks and few sources. The proposed protocol exploits a location information manager that manages location information of the sinks and the sources. We also compare the performance of the proposed protocol with the existing protocols through a simulation.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.813-819
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• 2008

Many shipping companies have suffered about high oil cost and environment regulation as people are concerned about the environment, therefore concentrating on energy using efficiency of the ship. The Skysails Company of Germany developed Skysails System for 4 years, making Shipping Company take interest under such situation. Skysails System uses a large kite in the ship, decreasing fuel expenses. So examination and utility analysis on Skysails System application are a necessity by using weather condition in the Coastal Waters of Korea where feeder network was well-developed. As a result, we could find out the system's efficacy on fuel saving and environment cost saving.

• Journal of KIISE:Databases
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• v.28 no.4
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• pp.715-722
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• 2001

Mobile computing has become a reality thank to the convergence of two technologies :powerful portable computers and the wireless networks. The restrictions of wireless network such as bandwidth and energy limitations make data broadcasting an attractive data communication method. This paper addresses the clustering of wireless broadcast data for multipoint queries. By effective clustering of broadcast data the mobile client can access the data on the air in short latency In the paper we define the data affinity and segment affinity measures. The data affinity is the degree that two data objects are accessed by queries, and the segment affinity is the degree that two sets of data (i.e segments) are accessed by queries Our method clusters data objects based on data and segment affinity measures we show that the performance of our method is scarcely infuenced by the growth of the number of queries.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.36-44
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• 2016

In this paper, an Impulse Radio-Ultra Wide band RF Transceiver for WBAN applications is implemented in $0.18{\mu}m$ CMOS technology. The designed RF transceiver support 3-5GHz UWB low band and employs OOK(On-Off Keying) modulation. The receiver employs non-coherent energy detection architecture to reduce complexity and power consumption. For the rejection of the undesired interferers and improvement of the receiver sensitivity, RF active notch filter is integrated. The VCO based transmitter employs the switch mechanism. As adapt the switch mechanism, power consumption and VCO leakage can be reduced. Also, the spectrum mask is always same at each center frequency. The measured sensitivity of the receiver is -84.1 dBm at 3.5 GHz with 1.579 Mbps. The power consumption of the transmitter and receiver are 0.3nJ/bit and 41 mW respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.840-845
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• 2007

In a wireless sensor network, a middleware used to support efficient processing and fast delivering of sensing data should handle the data loss problem at an intermediate sensor node caused by unexpected sudden data burst. In his paper, it proposes a Delta-Average method for enhancing the efficiency of data aggregation and correctness where the sensed data should be delivered only with the limited computing power and energy resource. With the proposed method, unnecessary data transfer of the duplicate data is eliminated and data correctness is enhanced by using the proposed averaging and data differentiating scheme when an instantaneous data burst is occurred. Finally, with the TOSSTM simulation results on TinyDB, we verify that the correctness of the transferred data is enhanced.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.439-459
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• 2010

Structural health monitoring (SHM) of civil infrastructure using wireless smart sensor networks (WSSNs) has received significant public attention in recent years. The benefits of WSSNs are that they are low-cost, easy to install, and provide effective data management via on-board computation. This paper reports on the deployment and evaluation of a state-of-the-art WSSN on the new Jindo Bridge, a cable-stayed bridge in South Korea with a 344-m main span and two 70-m side spans. The central components of the WSSN deployment are the Imote2 smart sensor platforms, a custom-designed multimetric sensor boards, base stations, and software provided by the Illinois Structural Health Monitoring Project (ISHMP) Services Toolsuite. In total, 70 sensor nodes and two base stations have been deployed to monitor the bridge using an autonomous SHM application with excessive wind and vibration triggering the system to initiate monitoring. Additionally, the performance of the system is evaluated in terms of hardware durability, software stability, power consumption and energy harvesting capabilities. The Jindo Bridge SHM system constitutes the largest deployment of wireless smart sensors for civil infrastructure monitoring to date. This deployment demonstrates the strong potential of WSSNs for monitoring of large scale civil infrastructure.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.5
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• pp.355-363
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• 2007

The Korean traditional 'Ondol' system has been a target for innovation to meet the requirements of sustainable domestic building and low carbon emission energy utilization. Simulation techniques provide designers and researchers with powerful tools to predict heating load and thermal behaviour of Ondol systems installed in various contexts. However, there are few studies on Ondol models, especially associated with multi-stories buildings of which type covers about 50% of Korean housing stock. In this study, we analyzed the double floor Ondol system on the multi-stories buildings using the ESP-r program. On the basis of the double floor Ondol system, we suggested the new modelling method that is composed of the Vent zone and Ondol zone. Using the this model, sensitivity analysis was carried out to refine the applicability of the model taking account of control conditions, constructions, air change and air flow network method and CFD analysis using the FLUENT. The air layer has enough temperature to use in heating zone. It is suggested that the simplicity of the model will allow building designers and mechanical engineers easily to implement scenario-based assessments of design options as well as control strategies. Later, we will simulate the real buildings and analyze the air distributions using the Fluent according to the various conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.25-32
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• 2019

The core of the block chain technology is solving the problem of agreement on double payment, and the PoW, PoS and DPoS algorithms used for this have been studied. PoW in-process proofs are consensus systems that require feasible efforts to prevent minor or malicious use of computing capabilities, such as sending spam e-mail or initiating denial of service (DoS) attacks. The proof of the PoS is made to solve the Nothing at stake problem as well as the energy waste of the proof of work (PoW) algorithm, and the decision of the sum of each node is decided according to the amount of money, not the calculation ability. DPoS is that a small number of authorized users maintain a trade consensus through a distributed network, whereas DPS provides consent authority to a small number of representatives, whereas PoS has consent authority to all users. If PoS is direct democracy, DPoS is indirect democracy. This study aims to contribute to the continuous development of the related field through the study of the algorithm of the block chain agreement.