Keizan, South Korea

Kyungil University

www.kiu.ac.kr
Keizan, South Korea

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Choi D.H.,Kyungil University | Kang D.H.,University of Seoul
Aerosol and Air Quality Research | Year: 2017

Air pollution due to PM2.5 is of public concern in Korea. Ambient PM2.5 can penetrate indoors through the building envelope, affecting the indoor PM2.5 concentrations. Most people stay indoors for approximately 80% of every day, implying that their primary exposure to PM2.5 could be determined by the indoor air. This study aims to investigate the infiltration of ambient PM2.5 through the building envelop in apartment housing units in Korea. The on-site infiltration test method, by using a blower-door depressurization procedure, was suggested in order to maintain an identical indooroutdoor pressure difference among the tests. On-site experiments were conducted in 11 apartment housing units to estimate the PM2.5 infiltration factors. The results showed that the average infiltration factor of all the test housing units was 0.65 ± 0.13 (average ± standard deviation), with a minimum of 0.38 and a maximum of 0.88. Furthermore, the results from the relation of the building airtightness data to the infiltration factors suggests that a leaky housing unit with high ACH50, or a high specific effective leakage area (ELA), would be more significantly influenced by the ambient PM2.5. The study demonstrated that the suggested infiltration test procedure was useful to assess the infiltration factors in conditions of controlled indoor-outdoor pressure differences in real housing units. © Taiwan Association for Aerosol Research.


Kang K.-S.,Kyungil University
Industrial and Engineering Chemistry Research | Year: 2012

The surface of silica spheres was modified using 3-mercaptopropyl trimethoxysilane (MPTMS) with an acid catalyst and a base catalyst. Large aggregation was observed for the spheres modified with an acid catalyst. The spheres modified with an acid catalyst (ACS) show aggregated spheres. However, no aggregation was observed for the spheres modified with a base catalyst (BCS). Aqueous lead solutions with 625 and 1663 ppm were used to test the removal of lead ions. Various amounts of modified spheres were treated to the lead solutions. The lead concentration drastically decreased with the increase of the amount of the spheres. The lead removal efficiency for the BCS is much more effective than that of ACS. For more-quantitative analysis of the residual lead concentration, inductive coupled plasma-mass spectrometry (ICP-MS) was employed. As the amount of spheres increased, the lead concentration drastically decreased. The lowest concentration of 1.2 ppb was obtained, which indicates that the lead ion can be completely removed from the aqueous system. © 2012 American Chemical Society.


Kim H.,Kyungil University
Communications in Computer and Information Science | Year: 2012

Radio frequency identification (RFID) system is a promising automatic identification technology that uses communication via radio waves to identify and track moving objects. Privacy and security concerns inhibit the fast adaption of RFID technology for many applications. A number of authentication protocols that address these concerns have been proposed but real-world solutions that are secure and maintain low communication cost are still needed and being investigated. Recently, Cho et al. proposed a hash-based RFID mutual authentication protocol and the protocol is secure. However, this paper proposes an enhanced hash-based RFID mutual authentication protocol to remedy the desynchronization problem in the previous protocol. This protocol requires little computation and achieves both privacy and authentication, making it sufficient enough for use in supply chain management. © 2012 Springer-Verlag.


Kim H.,Kyungil University
Communications in Computer and Information Science | Year: 2012

Wireless sensor networks (WSNs) have found their way into a wide variety of applications and systems with vastly varying requirements and characteristics. Key agreement in WSNs is a critical security issue due to their unattended and hostile deployment. Recently, Guo et al. proposed an efficient and non-interactive hierarchical key agreement protocol applicable to mobile ad-hoc networks. However, their protocol could not be applied to the WSNs as it is due to the WSN's uniqueness. Thereby, we propose a non-interactive hierarchical key agreement protocol over the hierarchical WSNs. Our revision could support security and robustness over the hierarchical WSNs. © 2012 Springer-Verlag.


The formation of N2O in NH3-SCR deNOx reaction over an on-site-used commercial V2O5-WO 3/TiO2 catalyst has been measured using an on-line IR system with a modified gas cell. The N2O could be formed by the SCR and NH3 oxidation reactions. These two reactions were particularly enhanced with the on-site-used sample. © 2010 Springer Science+Business Media, LLC.


Yoon E.-J.,Kyungil University
Information Technology and Control | Year: 2011

A strong designated verifier signature scheme makes it possible for a signer to convince a designated verifier that she has signed a message in such a way that the designated verifier cannot transfer the signature to a third party, and no third party can even verify the validity of a designated verifier signature. In 2008, Zhang and Mao proposed a novel ID- based strong designated verifier signature scheme based on bilinear pairings by combining ID-based cryptosystem with the designated verifier signature. However, Kang et al. pointed out that Zhang-Mao scheme did not satisfy the strong designated verifier signature property and then proposed an efficient ID-based designated verifier signature scheme that is strong and unforgeable. Nevertheless, this paper demonstrates that Kang et al.'s scheme is still vulnerable to universal forgery attacks and then proposes an improved scheme that not only can overcome such forgery attacks but also can provide more efficiency.


Kim H.,Kyungil University
International Journal of Security and its Applications | Year: 2014

Recent Federal Communications Commission rules promise a whole new set of possible applications, which allow unlicensed use on a secondary basis of the Television White Spaces (TVWS), called as cognitive radio technology. ECMA-International launched the first step towards realizing these applications by creating and adopting industry standards. This paper reviews the first industrial standards for personal/portable devices in the TVWS from ECMA-International focused on the security aspects. After that, we point out the lack of security facilities in the standard, which does support the link-to-link security but not for the end-to-end security, and then propose two location-based authentication protocols to cope up with the deficiencies over cognitive radio networks. We use location information as thesecurecredentialfor the authentications. The protocols can be support privacy issues of consumer premise equipments and integrated into the extensible authentication protocol. © 2014 SERSC.


Kim H.S.,Kyungil University
Journal of Network and Computer Applications | Year: 2011

The developing IEEE 802.22 standard will allow broadband access to be provided in sparsely populated areas by using cognitive radio techniques with operations on a non-interfering basis over television broadcast bands. Such non-interfering basis operation will increase the efficiency of utilisation of that spectrum, and provide large economic and societal benefits. However, the security mechanisms supported by IEEE 802.22 security sub-layer are insufficient to ensure robust security due to the fact that the designers of the standard attempted to reuse the security sub-layer designed for IEEE 802.16 networks, which does not consider the unique security features from IEEE 802.22 networks. This paper proposes a location-based authentication protocol for IEEE 802.22, which can be integrated with the extensible authentication protocol. The proposed protocol uses location information as a key factor to be authenticated each other. Furthermore, it could provide the privacy and confidentiality. © 2010 Elsevier Ltd. All rights reserved.


Park S.,Kyungil University
International Journal of Climatology | Year: 2011

Cokriging, a multivariate geostatistical interpolation method, uses elevation information as a secondary variable to improve the prediction accuracy of air temperature in mountainous areas. Although the secondary variable plays an important role in cokriging, the performance of interpolation largely depends on the amount of input data. The purpose of this study was to improve air temperature estimation by merging hypertemporal Moderate Resolution Imaging Spectroradiometer land surface temperature (LST) data and ground observations as interpolation data. Two significantly different island environments, tropical Hawaii Island (USA) and temperate Jeju Island (Korea), were selected for interpolation experiments. Spatiotemporal characteristics of air temperature prediction were compared between three cokriging methods and the conventional inverse-distance weighted interpolation. Due to the year-round trade winds, there was significant difference in prediction errors between windward and leeward slopes of Hawaii Island. LST-derived temperature was not regularly sampled from cloud-prone, windward slopes. As a result, prediction reliability was lower on windward slopes than leeward slopes, and overall prediction accuracy decreased in the wet season. Jeju Island is a mid-latitude volcanic island heavily influenced by the Asian monsoons. This climatic setting creates the seasonal variations of air temperature that is far greater than its spatial variations. The environmental lapse rate (ELR) of Jeju Island became much steeper in winter, and prediction accuracy and reliability were reduced due to an increase in the spatial variations of air temperature. With the addition of satellite-derived air temperature data, the root mean square errors of cokriging decreased by 27.3-52.9% for Hawaii Island and 34.6-37.6% for Jeju Island depending on cokriging models. © 2010 Royal Meteorological Society.


Yoon E.-J.,Kyungil University
Expert Systems with Applications | Year: 2012

Radio frequency identification (RFID) technology is taking the place of barcodes to become electronic tags of the new generation. EPC Class 1 Generation 2 has served as the most popular standard for passive RFID tags. In 2010, Yeh et al. proposed a new RFID authentication protocol conforming to EPC Class 1 Generation 2 standard. However, this paper demonstrates that Yeh et al.'s protocol has two serious security problems such as DATA integrity problem and forward secrecy problem unlike their claims. An improved protocol is also proposed which can prevent the security problems and be applied in low-cost RFID environments requiring a high level of security. © 2011 Elsevier Ltd. All rights reserved.

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