• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.179-184
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• 2012

A conventional wireless rf communication has relatively high ratio of power dissipation to transmit power for short-range links, susceptibility to interference, interception and jamming of electromagnetic wave. The study on alternative using ultraviolet signal to remedy the shortcomings of conventional rf communication has recently received attention. In this paper, the simulation results about the data rate performance of ultraviolet non-line-of-sight communication are provided. It is found that the direction of transmitting beam, receiving field of view width and the transmitting signal power have a seriously effect on the data rate of on-off-keying non-line-of-sight ultraviolet communication.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.595-600
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• 2007

Greater expansion and more frequent operation of the railroad transportation system anticipated due to its characteristics including low cost, safety and mass transportation. Recently, effects on the railway structures due to expansion of newly constructed road, construction of subway, city gas pipeline, communication network, electric power network and construction of other railway underground crossing in accordance with urban planning and organization has influenced safe operation of trains. Accordingly, standard for selection of construction method that will enable construction of more economical and rational subway underground crossing structures by preventing problems occurring at the time of above construction works and accidents in safe operation of trains due to construction in advance is definitively necessary. Although there are numerous construction methods that can be applied at the time of construction of railway underground crossing, there are much difficulties in selection of appropriate construction method that considers characteristics of each construction method on non-excavation type construction method, train operation plan of number of operational routes and on-site circumstances. Therefore, this research aims to present rational standard for selection of construction method for such, and standard for slowdown speed and interception of train when passing the areas of slowdown in sectors under construction.

• Journal of Korean Institute of Fire Investigation
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• v.11 no.1
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• pp.66-73
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• 2008

In this research, the electric power consumptions of the electrical machinery and appliances selected in the Seoul division of Korea Electrical Safety Corporation were measured. The power-saving efficiency was investigated by comparing the amounts of the reserved electric power when the Saver was on or off through measuring that of the reserved electric power before and after equipping the selected appliances with the Saver, a cutoff of the reserved electric power. As a result, the power-saving efficiency was around 18% when the Saver was installed. It can be ascribed to the removal of the source wasting electrical energy. Furthermore, by blocking the reserved electric power, the electric fire can be originally prevented and also the life time of the electrical machinery and appliances can be postponed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.231-233
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• 2013

A lot of information is exchanged using data communications in today's modern society. Nowadays many important communications are susceptible to interception and theft for malicious purposes, and is under threat from hackers. Crackers are able to hack into data flows even if the data is encrypted. To ensure strong encryption properties, these cryptographic algorithms are often a burden on devices used for authentication such as a PC or smart phone. This paper proposes an authentication system using the Arduino module. Implementation and application of the communication scheme is designed to minimize the burden of delivering data communication between devices especially where password and encryption is concerned.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.1-5
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• 2000

Leaf area is critical for crop light interception, and thereby has a substantial influence on crop yield. This experiment was conducted to characterize the development of soybean [Glycine max (L.) Merr.] leaf area. Plastochron index and leaf relative growth rate of Jackson was contrasted with the PI416937, which also has demonstrated tolerance to drought. First, plastochron ratio (PR) and plastochron index (PI) were evaluated in greenhouse to compare the leaf growth rate between two genotypes under well-watered condition. There was reasonable constancy of PR between two genotypes. The PR means of Jackson and PI416937 were 0.41 and 0.44, respectively. A fairly smooth increase of PI during vegetative stage was observed. Second, the relative growth rates were graphed against leaf area, normalized with respect to final leaf area, under well-watered and water-deficit conditions. Leaf growth was sustained longer in well-watered condition than water-deficit condition and there was a sizable proportion of leaves which was ceased earlier their growth in water-deficit condition compared to well-watered condition. The leaf relative growth rate of Jackson until leaves had completed at 45% of their growth during water deficit period was higher than that of PI416937.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.1
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• pp.31-39
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• 2011

VoIP service uses packet network of ip-based because that has eavesdropping, interception, illegal user as vulnerable elements. In addition, PSTN of existing telephone network is subordinate line but VoIP service using the ip packet provide mobility. so The user authentication and VoIP user's account service using VoIP has emerged as a problem. To solve the vulnerability of SIP, when you use VoIP services with SIP, this paper has made it possible to authenticate user's terminal by using proxy server and proxy server by using authentication server. In conclusion, sender and receiver are mutually authenticated. In the mutual authentication process, the new session key is distributed after exchanging for the key between sender and receiver. It is proposed to minimize of service delay while the additional authentication. The new session key is able to authenticate about abnormal messages on the phone. This paper has made it possible to solve the vulnerability of existing SIP authentication by using mutual authentication between user and proxy server and suggest efficient VoIP service which simplify authentication procedures through key distribution after authentication.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.1
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• pp.8-17
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• 1987

Four foreign pasture cultivars such as Lotus corniculatus cv. Maitland, Trifolium pratense cv. Deben, Lolium perenne cv. $S_{23}$ and .Dactylis glomerata cv. $S_{26}$ were tested with "Kwisan" series, a common upland soil in Southern part of Korea. The cultivars in single or mixture were grown in pot with two levels of light intensity, i.e. a full sun light condition and 50% interception. Dry matter yield of top and root and their seasonal changes, the number of tillers or branches per plant and finally competative effects of mixtures were evaluated by estimating the expected yield, relative yield totals and compensation index. The results are summarized as follows: 1. Maitland showed a significant decrease in dry matter yield in shade condition, but the number of branches of Maitland was higher than those of Deben. 2. Maitland showed higher dry matter yield than Deben during the mid-summer period, while $S_{23}$, showed higher dry matter yield than $S_{26}$ during early season. 3. Mixtures of $S_{23}$ and Maitland, and $S_{26}$ and Deben gave better response to grasses by increasing the number of tillers in shade condition. 4. Combinations of Lotus corniculatus cv. Maitland and Dactylis glomerata cv. $S_{26}$ and Trifolium pratense cv. Deben and Dactylis glomerata cv. $S_{26}$ gave higher relative yield totals and higher compensation index, which envisages that the pasture establishment rates can be enhanced when those mixtures were sown by the oversowing method in the upland soil where phosphate level is very low and infertile in general.n general.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.924-944
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• 2017

Telecare Medical Information System (TMIS) helps the patients to gain the health monitoring information at home and access medical services over the mobile Internet. In 2015, Das et al proposed a secure and robust user AKA scheme for hierarchical multi-medical server environment in TMIS, referred to as DAKA protocol, and claimed that their protocol is against all possible attacks. In this paper, we first analyze and show DAKA protocol is vulnerable to internal attacks, impersonation attacks and stolen smart card attack. Furthermore, DAKA protocol also cannot provide confidentiality. We then propose a lightweight pseudonym AKA protocol for multi-medical server architecture in TMIS (short for PAKA). Our PAKA protocol not only keeps good security features declared by DAKA protocol, but also truly provides patient's anonymity by using pseudonym to protect sensitive information from illegal interception. Besides, our PAKA protocol can realize authentication and key agreement with energy-saving, extremely low computation cost, communication cost and fewer storage resources in smart card, medical servers and physical servers. What's more, the PAKA protocol is proved secure against known possible attacks by using Burrows-Abadi-Needham (BAN) logic. As a result, these features make PAKA protocol is very suitable for computation-limited mobile device.

• Applied Chemistry for Engineering
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• v.17 no.1
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• pp.62-66
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• 2006

In this work, the properties of environmentally friendly functional panel made from waste aluminum were investigated. Product quality enhancement was pursued through an improved viscosity process, a mixing process by agitating, a foaming process, a cooling process, and a color addition process. An acoustic transmission attenuation test, a sound adsorption rate measurement test, and a foaming condition and scrap mixing test were implemented. As a result, the functional panel made from waste aluminum was ultra lightweight and had excellent properties such as soundproof, sound interception, and shielding harmful electromagnetic waves. Also, the functional panel showed low thermal conductivity (about 2.2 kcal/mh) and excellent heat-insulating property.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5610-5624
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• 2017

A novel scheme based on polarization modulation and the weighted fractional Fourier transform (PM-WFRFT) is proposed in this paper to enhance the physical layer security of dual-polarized satellite systems. This scheme utilizes the amplitude and phase of the carrier as information-bearing parameters to transmit the normal signal and conceals the confidential information in the carrier's polarization state (PS). After being processed by WFRFT, the characteristics of the transmit signal (including amplitude, phase and polarization state) vary randomly and in nearly Gaussian distribution. This makes the signal very difficult for an eavesdropper to recognize or capture. The WFRFT parameter is also encrypted by a pseudo-random sequence and updated in real time, which enhances its anti-interception performance. Furthermore, to prevent the polarization-based impairment to PM-WFRFT caused by depolarization in the wireless channel, two components of the polarized signal are transmitted respectively in two symbol periods; this prevents any mutual interference between the two orthogonally polarized components. Demodulation performance in the system was also assessed, then the proposed scheme was validated with a simulated dual-polarized satellite system.