• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.71-78
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• 2004

Dedicated Short Range Communications(DSRC) as a prominent communications candidate for Intelligent Transportation Systems(ITS) have been developed to support ITS applications such as value-added information service, e-commerce, electronic toll payment, etc. These various applications associated with electronic payment through unsecure communication channel of DSRC suffer from security threats. To ensure secure payment, we have adopted appropriate cryptographic mechanisms including encipherment, authentication exchange and digital signature. The cryptographic mechanisms require to use cryptographic keys established between two communication entities. In this paper, we propose a secure electronic payment system which is designed to have some functions for strong authentication, encryption, key agreement, etc. Especially, we adopt domestic developed cryptographic algorithms such as EC-KCDSA and SEED for digital signature and block cipher, respectively. We can show those mechanisms are appropriate for the secure electronic payment system for ITS services under the DSRC wireless environment in aspects of constrained computational resource use and processing speed.

• Journal of Korea Multimedia Society
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• v.17 no.1
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• pp.94-103
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• 2014

Asthma is a chronical disease which could be controled by constant management and the patients may lead their daily lives if they are properly supervised. South Korea is one of the most wired nations, and its penetration rate of smart phones will exceed 80% of entire population this year, so managing asthma and communicating with medical staffs with mobile applications, will be very reasonable solution. In this study, medical staffs, developers and UI/UX experts co-worked developed an Android-based application for asthma management. To tell the effectiveness and availability, we made asthma sufferers use this mobile application for more than six months. After six months we surveyed and interviewed the patients. We could find merits and demerits of the applications and we finally suggested new guidelines for version 2.0.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.641-650
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• 2001

In recent years, e-Commerce is very active on the Internet, especially the World Wide Web along with the popularization of Internet using high-speed networks. Especially, Electronic Software Distribution(ESD) is widely being focused as one of the popular researches. However, the existing models of ESD lack substantial illegal copy protection or copyright protection as they have the shortcomings of guaranteeing anonymity of users. This study suggests an ESD protocol that guarantees substantial copyright protection and anonymity based on the Public Key Infrastrncture(PKl). The suggested method does not give the information of a buyer who doesn't want to reveal to a seller, and protects illegal copy and distribution as well. When it happens that illegal copies are in circulation, this method provides a device to trace back its original distributor so that it helps protect the copyright. In addition, it provides more convenient environment to the user by not using the methods of serial number input and extra installation to use.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.182-190
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• 2007

Virtual world is the 3D graphical interactive environment that networked by electronic communications. Virtual Worlds offered flow experience for a long time to their users. They blur the boundaries of work and play, so bring out the concept of Fun Labor. If we can accept the principle of equivalence between Fun Labor and Real Labor, the Fun Labor may be one of the solutions of the large unemployment problem in the information society. And the Fun Labor is the new type of labor that corresponds the subjectivity of users who want interesting experience as much as they spend money and times. This situation means that the users of Virtual worlds are structuring the identities as the Residents who act the Fun Labor. It'll be very important to examine the social effects of this situation.

• Environmental Analysis Health and Toxicology
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• v.24 no.2
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• pp.169-178
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• 2009

To investigate the inhibitory effects of Peonia japonica water extract(PJWE) on skin wrinkle formation, skin wrinkles were induced by both the irradiation of UVB and the application of squalene monohydroperoxide to the backs of hairless mice for 4 weeks. And at the same time experimental materials were applied topically. Wrinkles for the control (C) group were formed as a pattern of deep furrows and thick crests. Whereas wrinkles for the positive control (PC, 0.01% retinoic acid) and experimental(E, PJWE) groups were formed as a pattern of shallow furrows and thin crests, which were similar to that of the normal(N) group. Collagen and elastic fibers in dermis of the PC and E groups were almost intact with a regular arrangement, which were similar to those of the N group. The activity of xanthine oxidase, the free radical generating enzyme, was significantly lower in the E group than the C and PC groups. The activities of superoxide dismutase and catalase, the free radical scavenging enzymes, were much higher in the E group than the C and PC groups and similar to the N group. As for the amount of matrix metalloproteinase-3(MMP-3) expression, PC and E groups were significantly lower than the C group. Therefore, PJWE could be very effective natural herbal material for the inhibition or improvement of wrinkle formation in hairless mice skin.

• Environmental Analysis Health and Toxicology
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• v.24 no.2
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• pp.159-167
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• 2009

To investigate the alleviative effects of Peonia japonica water extract(PJWE) on inflammation and skin barrier damage, both the irradiation of UVB and the application of squalene monohydroperoxide (Sq-OOH) to the backs of hairless mice were performed for 4 weeks. And at the same time experimental materials were applied topically. The skin erythema indices for the positive control (PC, 0.01% retinoic acid) and experimental (E, PJWE) groups were lower than that of the control (C) group. Whereas both the lipid and water capacities for the PC and E groups were higher than those of the C group. Epidermis and dermis of the C group were remarkably thickened in comparison with the PC and E groups. Relatively much less number of inflammatory cells, including lymphocytes, neutrophils and macrophages were found in dermis of the PC and E groups compared with the C group. Lipid lamellae of the C group were broken severely showing an irregular arrangement and lipid content was much reduced. Whereas those of the PC and E groups were almost intact with a regular arrangement, which were similar to that of the N group. Taken the results all together, it was confirmed that PJWE could be effective natural herbal material for the alleviation of inflammation and skin barrier damage in hairless mice skin which were induced by UVB and Sq-OOH.

• Environmental Analysis Health and Toxicology
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• v.24 no.2
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• pp.137-148
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• 2009

This study quantitatively investigated the emissions of indoor air pollutants associated with the utilization of air fresheners indoors, and evaluated individual exposure to five specified indoor air pollutants, which were chosen on the basis of selection criteria. An electrically-polished stainless steel chamber (50L) was employed to achieve this purpose. Test air fresheners were selected through three steps: first, on the basis of market sales; second, on the basis on a preliminary head-space study; and lastly, on the basis of emissions of toxic compounds (benzene, ethyl benzene, limonene, toluene, and xylene). The empirical mathematical model fitted well with the time-series concentrations in the environmental chamber (in most cases, determination coefficient, $R^2{\gtrsim}$0.9), thereby suggesting that the empirical model was suitable for testing emissions. The concentration equilibrium appeared 180 min after the introduction of sample air fresheners into the chamber. Both the chamber concentrations of emission rates or factors varied greatly according to air freshener type. It is noteworthy that although benzene, ethyl benzene, toluene, and xylene were emitted from all test air fresheners, their exposure levels were not significant enough to result in any significant health risk. However, certain type of air fresheners were observed to emit significant amount of limonene, which is potentially reactive with ozone to generate secondary pollutants with oxidants such as ozone, hydroxyl radicals, and nitrogen oxides. The exposure levels to limonene associated with the utilization of three air fresheners were estimated to be 13 to 175 times higher than that of other air fresheners. This information can help consumers to select low-pollutant-emitting air fresheners.

• Journal of the Korean Professional Engineers Association
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• v.28 no.3
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• pp.121-134
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• 1995

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the unit con-trol devices located In common manufacturing zone and operated by connecting them. The network management system, which controls and supervises the network resources in the communication network, is the function that is necessarily required in this net-work. For the stability in this network, this paper measures the variation of data packet length and node number and analyzes the variated value of the token rotation time and waiting time for the network operation. On the evalution of the performance, the data packet length varies from 10 bytes to 100 bytes in the operation of the group manage-ment network, the variation of the token rotation time and waiting time is less than 10 msec. When the variation of the data packet lenhth is less than 50 bytes, differences in token rotation time or waiting time is unnoticable. Since the waiting time in this case is less than 10 msec, response time Is fast enough.

• Journal of Internet of Things and Convergence
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• v.5 no.2
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• pp.73-79
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• 2019

Research is underway on services and systems that provide real-time alerts for suffocating gases and potentially explosive materials, but currently smart bend type services are lacking. This study supports real-time identification of explosion hazards due to static electricity in the workplace and immediate elimination of accident occurrence factors, real-time monitoring of worker status and workplace hazards (oxygen, hazardous chemical concentration), and immediate warning and data in case of danger. We propose a method of establishing an accident prevention system through analysis. In this way, various accidents that may occur in industrial sites are monitored using IoT-based intelligent sensor nodes, wireless network technology, data processing middleware, and integrated control system, and real-time risk information at the industrial sites is prevented and accidents are prevented. By supporting a safe working environment, the company can significantly reduce costs compared to post-procurement costs.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.433-440
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• 2007

Recently, the reduction of standby power consumption is significantly issued in electronic and electrical industry for the conservation of environment. In the case of a switched mode power supply (SMPS), it is demanded high efficiency at extremely low output power conditions by consumers. However, it is very different from high efficiency techniques at full load conditions. In addition, many SMPSs are designed as a multi-output circuit for various loads because of cost down. This circuit is difficult to implement both high efficiency and good cross regulation performance, simultaneously. In this paper, secondary side post regulator (SSPR), current mode control method, and power sequence control technique are proposed to reduce standby power consumption and to improve cross regulation performance of the multi-output SMPSs which consist of single or multiple converter. The proposed methods are analyzed by their operational principles and optimal designs verified by experimental results with 110[W] and 270[W] SMPSs.