• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2660-2679
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• 2017

Crypton is a SP-network block cipher that attracts much attention because of its excellent performance on hardware. Based on Crypton, mCrypton is designed as a lightweight block cipher suitable for Internet of Things (IoT) and Radio Frequency Identification (RFID). The security of Crypton and mCrypton under meet-in-the-middle attack is analyzed in this paper. By analyzing the differential properties of cell permutation, several differential characteristics are introduced to construct generalized ${\delta}-sets$. With the usage of a generalized ${\delta}-set$ and differential enumeration technique, a 6-round meet-in-the-middle distinguisher is proposed to give the first meet-in-the-middle attack on 9-round Crypton-192 and some improvements on the cryptanalysis of 10-round Crypton-256 are given. Combined with the properties of nibble permutation and substitution, an improved meet-in-the-middle attack on 8-round mCrypton is proposed and the first complete attack on 9-round mCrypton-96 is proposed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4205-4227
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• 2018

Network Coding (NC) is an approach recently investigated for increasing the network throughput and thus enhancing the performance of wireless mesh networks. The benefits of NC can further be improved when routing decisions are made with the awareness of coding capabilities and opportunities. Typically, the goal of such routing is to find and exploit routes with new coding opportunities and thus further increase the network throughput. As shown in this paper, in case of proactive routing the coding awareness along with the information of the measured traffic coding success can also be efficiently used to support the congestion avoidance and enable more encoded packets, thus indirectly further increasing the network throughput. To this end, a new proactive routing procedure called Congestion-Avoidance Network Coding-Aware Routing (CANCAR) is proposed. It detects the currently most highly-loaded node and prevents it from saturation by diverting some of the least coded traffic flows to alternative routes, thus achieving even higher coding gain by the remaining well-coded traffic flows on the node. The simulation results confirm that the proposed proactive routing procedure combined with the well-known COPE NC avoids network congestion and provides higher coding gains, thus achieving significantly higher throughput and enabling higher traffic loads both in a representative regular network topology as well as in two synthetically generated random network topologies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4336-4354
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• 2018

Fuzzy C-means (FCM) algorithm is a most usually technique for medical image segmentation. But conventional FCM fails to perform well enough on magnetic resonance imaging (MRI) data with the noise and intensity inhomogeneity (IIH). In the paper, we propose a Gamma correction conditional FCM algorithm with spatial information (GcsFCM) to solve this problem. Firstly, the pre-processing, Gamma correction, is introduced to enhance the details of images. Secondly, the spatial information is introduced to reduce the effect of noise. Then we introduce the effective neighborhood mechanism into the local space information to improve the robustness for the noise and inhomogeneity. And the mechanism describes the degree of participation in generating local membership values and building clusters. Finally, the adjustment mechanism and the spatial information are combined into the weighted membership function. Experimental results on four image volumes with noise and IIH indicate that the proposed GcsFCM algorithm is more effective and robust to noise and IIH than the FCM, sFCM and csFCM algorithms.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.2
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• pp.81-92
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• 2013

Purpose : This research was carried out to find how neck exercise program combined with self stretching and muscle strengthening program influences on smart phone addicts with forward head posture. Methods : The subjects of this study were 20 smart phone-addicts with forward head posture and we divided them into 2 groups. The experimental group(10 people) participated in neck exercise program as a intervention for 3 months and the control group(the other 10 people) didn't participate in neck exercise program. Neck exercise program were composed of self stretching and muscle strengthening program. Then we measured cervical alignment with GPS(Global Posture System) and evaluated balance ability with Balance Master ver 7.0 systems. Results : The result were as follows. 1. After the intervention, experimental group were significantly more closed to normal cervical alignment than control group. 2. After the intervention, experimental group increased in dynamic balance ability a little more than control group. Conclusion : Neck exercise program seems to get cervical alignment better and improve balance ability.

• International Journal of Automotive Technology
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• v.7 no.6
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• pp.653-658
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• 2006

The enormous increase in the use of fossil energy sources throughout the world has caused severe air pollution and a depletion of energy. Besides, it seems very difficult to comply with the upcoming stringent emission standards in vehicles. In order to develop low emission engines, research on better qualified fuels as alternative fuels to secure high engine performance becomes a more important issue than ever. Since sulfur contained in diesel fuel is transformed in sulfate-laden particulate matters when a catalyst is applied, it is necessary to provide low sulfur fuels before any Pt-based oxidation catalysts are applied. But the excessive reduction of sulfur levels may cause the lubricity of fuel and engine performance to degrade. In this aspect, biodiesel fuel derived from rice bran is applied to compensate viscosity lost in the desulfurization treatment. This research is focused on the performance of an 11,000cc diesel engine and the emission characteristics by the introduction of ULSD(Ultra Low Sulfur Diesel), BD20(Diesel 80%+Biodiesel 20%) and a diesel oxidation catalyst, where BD20 is used to improve the lubricity of fuel in fuel injection systems as fuel additives or alternative fuels.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.4-11
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• 2005

In this paper, we propose novel optics design for media inside near-field recording (NFR) using hemispherical solid immersion lens (HMS). To obtain strong advantage of data protection and high data capacity simultaneously, HMS based near field optics using aplanatic position of super hemisphere is designed. In this design, to improve small optical tolerance of this aplanatic position, additional aspheric lens surface is added on top of the HMS and it is combined with zoom optics which composed of two single lenses having low numerical aperture (NA). Also, to compensate chromatic aberration which happens seriously in optics using blue laser diode, diffractive optical element is used. Using zoom optics, additional aspheric lens surface, and diffractive optical element together, wavefront aberration and chromatic aberration are effectively reduced in broad range of cover layer thickness and wavelength variation. In addition, In this paper, effect of gap induced aberration is investigated by analyzing different behavior of each TM and TE wave for designed media inside dual-layer NFR optics.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.8
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• pp.486-494
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• 2006

In this paper, we introduce a new solution for the load balancing problem, an important issue in parallel processing. Our heuristic load balancing technique called MGA effectively combines the benefit of both mean-field annealing (MFA) and genetic algorithms (GA). We compare the proposed MGA algorithm with other mapping algorithms (MFA, GA-l, and GA-2). A multiprocessor mapping algorithm simulation has been developed to measure performance improvement ratio of these algorithms. Our experimental results show that our new technique, the composition of heuristic mapping methods improves performance over the conventional ones, in terms of solution quality with a longer run time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1650-1658
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• 1998

This paper describes how to remove echoes effectively using speech parameter information provided form speech coder. More specially, the proposed adaptive echo canceller utilizes the excitation signal or linearly predicted error signal instead of output speech signal of vocoder as the input signal for adaptation algorithm. The normalized least mean ssquare(NLMS) algorithm is used for the adaptive echo canceller. The proposed algorithm showed a fast convergece charactersitcis in the sinulatio compared to the conventional method. Specially, the proposed echo canceller utilizing the excitation signal of speech coder showed about four times fast convergence speed over the echo canceller utilizing the output speech signal of the speech coder for the adaptation input.

• Electrical & Electronic Materials
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• v.8 no.2
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• pp.229-236
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• 1995

Multimedia has created a system environment that needs a combination of diverse peripherals, faster I/O, and easier configuration. The sheer volume of data one can expect with multimedia hardware and applications storage systems of higher capacity and faster data transfer rate. Unlike the magneto-optical(MO)disk technology which uses bias magnetic field in writing, both the reading and the writing in the phase change (PC) technology are performed only by laser light. In PC optical media, an active layer is reversibly converted between amorphous state and crystalline state by changing irradiation conditions of focused laser beam. Thus, as compared with MO disk, the PC disk has such great advantages that signals can be reproduced by change of reflectance of laser beams in the same manner as the compact disc. The reflectivity of a phase-change spot can be altered in a single pass under the head only through modulation of laser power. The principles and the current status of phase-change optical recording media combined with possible applications are discussed in the present article.

• Journal of ILASS-Korea
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• v.18 no.1
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• pp.21-26
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• 2013

Diesel low temperature combustion (LTC) is the concept where fuel is burned at a low temperature oxidation regime so that $NO_x$ and particulate matters (PM) can simultaneously be reduced. There are two ways to realize low temperature combustion in compression ignition engines. One is to supply a large amount of EGR gas combined with advanced fuel injection timing. The other is to use a moderate level of EGR with fuel injection at near TDC which is generally called Modulated kinetics (MK) method. In this study, the effects of fuel injection pressure on performance and emissions of a single cylinder engine were evaluated using the latter approach. The engine test results show that MK operations were successfully achieved over a range of with 950 to 1050 bar in injection pressure with 16% $O_2$ concentration, and $NO_x$ and PM were significantly suppressed at the same time. In addition, with an increase in fuel injection pressure, the levels of smoke, THC and CO were decreased while $NO_x$ emissions were increased. Moreover, as fuel injection timing retarded to TDC, more THC and CO emissions were generated, but smoke and $NO_x$ were decreased.